Any serious construction begins with drawing up a project. This allows you to assemble and place in the room in advance, even at the level of diagrams and drawings, all the engineering communications necessary for comfortable stay. The main ones, along with gas supply, heating and garbage disposal, are cold and hot water supply with sewerage and drains.
For the convenience of planning and reading designed documentation during construction, GOST developed, approved and regulated in SNiP the symbols of all systems installed on construction sites, as well as sanitary requirements for each of them. They also include detailed symbolism of the units required to supply water to the house, filter it and remove it from it as part of sewer waste.
This table shows all the design symbols for water supply and sewerage communications used in construction:
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The symbols for water supply and sewerage are uniform throughout the Russian Federation and CIS countries. Changing them at your own discretion is unacceptable. The reason is simple: a drawing for the plumbing arrangement of a facility should be understood by any trained plumber. This will help to avoid mistakes in the work technology and, ultimately, provide the most efficient way to operate the water supply of the facility.
Conventional signs on drawings and diagrams for the installation of plumbing should be indicated during the construction of any construction project, be it a multi-storey building, a cottage or any industrial building. They also apply in computer programs, for example, AutoCAD, used in creating projects for water supply and sewerage facilities.
Features of drawing up diagrams and drawings
Plumbing symbols for various components are used both in diagrams of the object and in its drawings. Both types of graphical display of communications, in general, perform the same task - creating a working draft, which is the main document when carrying out construction work.
A scheme is an idea, the beginning of everything, most often based on a specific technical task. It runs on any medium, including a simple notepad. All elements of the upcoming design can be recorded here quite conditionally, only with the designation of installation nodes and their communication connections at the site. For example, like this:
However, more informative are the diagrams, which indicate the projection of the communications being constructed and the symbols of all proposed nodes. Depending on the need, two types of projections are used in the diagrams - two-dimensional and three-dimensional (isometric).
Two-dimensional ( axonometric) diagrams allow you to represent an object in two planes: length and height or length and width:
Isometric projection more informative. It makes it possible to immediately estimate the working area in terms of length, width and height:
Even more visual for the designer is a three-dimensional image in 3D computer format. With its help it is much easier to maintain the scale and required dimensions.
The presence of all dimensions in all three planes, made to a given scale, turns a detailed and accurately executed diagram into a drawing. All drawings in construction projects are made on paper. This makes them more convenient for use on sites. On large construction sites equipped with computers, information is duplicated on special websites with the ability to view each drawing section in 3D.
The main task of the project is to create a plan that takes into account all the details of supplying cold and hot water to the site and its subsequent sewerage.
The specification of the proposed drawings is also important, in particular data on the wells available at the construction site, as well as the topography of the area. In addition, the project includes all certified materials necessary for the work.
All symbols on the drawings must comply with GOST. Otherwise, it will be impossible to carry out installation work accurately. It is also necessary to take into account the requirements of SPDS (design documentation system for construction) for the development and recording of documentation intended for the installation of plumbing fixtures at construction sites. Only in this way can you gain confidence that your home’s water supply and sewage system will operate efficiently and safely.
Symbols on drawings for water pipelines
Before developing a water supply project for any building and, in particular, country house the entire group of factors that can affect the functioning of the water supply system is identified.
Such factors include, first of all, the presence or absence of a centralized water supply network near the construction site, and whether it can lead to pressure drops. If there is no network, a local water supply system is designed with the installation of a storage tank.
The process of creating a project goes through several stages:
- Based on the total number of water consuming points in the house and on the site, the maximum load on the water supply system is calculated.
- Methods are being developed to compensate for water supply when pressure drops in the central or local network.
- A drawing is being drawn up.
- Equipment is selected according to the selected scheme.
In order to correctly place the water supply symbols on the drawings of the project being designed, the designer needs to imagine what elements the water supply system consists of. The number of plumbing elements and the material from which it is made plumbing fittings, may vary in cost and quality, but this does not fundamentally change anything.
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The symbols of pipeline diagrams and the corresponding equipment of the water supply system in all cases remain approximately as follows:
- well (or other source);
- pump;
- storage tank with tee;
- two outlet pipes: one for home water supply, the other for technical water supply (garden, vegetable garden);
- water filtration system for home with tee;
- two outlet pipes: one for cold water, the other for hot water.
Conditional graphic symbols pipelines are aimed at showing the distribution system of hot and cold water pipes.
Cold water from the tee of the filtration system it enters the collector installed in the house. From there it is distributed through pipes to existing plumbing points.
Hot water is supplied to the heater and then distributed point by point in the same way. This diagram clearly demonstrates this:
Sewerage: design features
The sewage system in any home or industrial premises is divided into internal and external modules. The first covers cleaning inside buildings, the second covers external sewerage around the house.
The internal sewerage module is formed from a network of pipelines combined into one complex. This module has only one outlet from the house, connected to the outdoor module via a check valve, which prevents the system from overflowing with water if the external tanks are overfilled.
into which all internal and external drains from external sewer lines are drained, including storm drains, if there is one on the site.
Storm water drainage system
What types are there, who does the maintenance and installation features
During design, a number of calculations are made. The main ones are:
- determining the location of plumbing units indoors and how to connect them to the sewer system;
- choice of drainage methods (forced or self-drainage). In the case of self-draining water, the slope of the pipes is calculated, as well as their markings.
In addition, the project takes into account:
- requirements for the ecology of the area adjacent to the house: a cesspool with a septic tank cannot be located near wells with drinking water;
- method of drainage of sewage. It can be autonomous with disposal through a cesspool or centralized with waste removal through a community-wide sewerage system located near the house.
Symbols for internal sewerage
Internal sewerage is designed to drain wastewater from all plumbing installations located in the premises. The water formed as a result of the life activity of its inhabitants mainly moves through pipelines installed with a certain slope, naturally. In rare cases, this requires forced promotion.
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The rooms in which the plumbing is located are planned close to each other. This helps drain the drain faster and reduces the likelihood of drain clogging.
To avoid the appearance of unpleasant odors on each plumbing fixture When planning, water-locking siphons are provided. The end of the pipe connecting all the outlets is led outside the building through the wall.
The designation of the sewerage system must take into account both internal and external sewer networks.
Internal sewerage includes signs indicating:
- outlets from all sanitary facilities located in the premises;
- risers that allow pumping wastewater from the upper floors to the lower ones;
- collectors collecting wastewater from various sources;
- exhaust systems;
- treatment plants;
- ventilation pipelines;
- cleaning pipes;
- hydraulic valves that prevent the penetration of unpleasant odors from the sewer system;
- sewer plugs.
The designation of the sewer plug is mandatory. If there are several plugs, the location of each should be indicated on the drawing.
The internal sewerage system in residential premises is designed in the isometry of pipelines with symbols, primarily as a system for household waste. At the same time, drains connected to the storm sewer or special trays around the perimeter of the building. A special siphon is installed at the point where wastewater is discharged from the house.
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The symbol in the sewer axonometry includes elements that are the source of sewer waste:
- sanitary facilities equipment (baths, sinks, toilets, bidets);
- dishwashers and washing machines;
- industrial equipment with waste water systems.
The flushing devices are connected to the water supply. Wastewater is directed into the external sewer through siphons, which are also hydraulic seals - U-shaped pipes with water. Each siphon is connected to a pipe with holes for inspection in case of blockage.
The drawing also conventionally shows sewerage pipe inlets, as well as their shaped parts, with the help of which wastewater is diverted to cast iron or plastic risers - tees, elbows, crosses. Also indicated in the drawing is an attic outlet for the riser to the roof, which prevents the room from being polluted with unpleasant odors.
Graphic symbols on drawings of external sewerage
External sewerage covers water treatment and drainage outside the home. It can be all-alloy, semi-dividing, dividing. All-alloy sewerage is designed to collect all types of sewage into a collector and then direct it to the treatment network.
Semi-separating sewerage is aimed at removing all rainfall without separating it into polluted and clean.
Symbols for sewerage in the drawings of the separation system include stormwater and domestic service networks.
Storm drains collect rain or industrial wastewater and discharge it into a sewer well or reservoir without preliminary treatment.
The sewer network, intended for domestic needs, passes atmospheric precipitation or wastewater of industrial origin through special system filtration.
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Graphic signs on wiring diagrams necessarily display:- devices for receiving waste water;
- drainage pipes;
- external sewer riser;
- exhaust ventilation pipe;
- hydraulic shutter;
- outlet;
- yard sewerage network;
- sewer well with cover;
- drainage funnel;
- internal sewer riser.
Each of these elements has a specific function in the system of reception, transmission and treatment of sewer and storm drains, and therefore must be installed both in the house and in the area adjacent to it.
Summary of the article
The meaning of symbols in practice construction design difficult to overestimate. In the process of studying the material, a large amount of information is processed, relating not only to the equipment installed at the site. It is important to create a drawing that would be understandable to those directly performing the work: it should be easy to read.
This is what the symbols are for. They can be alphabetic, numeric, but the most visual is the graphic, symbolic version.
The pictograms used by the project executor allow the master reading the drawing to easily determine which element of the system being created should be installed and where. This greatly simplifies the process of installing water supply and sewerage on site.
The great advantage of symbols is that with their help, according to GOST, you can put on the drawing not only plumbing communications, but also the plumbing itself: sink, faucets, bathtub, shower, toilet.
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Each of these elements is displayed in the form of a specific picture. This makes it possible to immediately understand what should be installed in one place or another, and, ultimately, carry out the work more quickly and efficiently.The hydraulic circuit is an element technical documentation, which uses symbols to show information about the elements of the hydraulic system and the relationships between them.
According to the ESKD standards, hydraulic circuits are designated in the main inscription code by the letter “G” ( - by the letter “P”).
As can be seen from the definition, on hydraulic diagram Conventionally, elements are shown that are connected to each other by pipelines - indicated by lines. Therefore, in order to correctly read a hydraulic diagram, you need to know how this or that element is indicated on the diagram. The symbols of the elements are specified in GOST 2.781-96. Study this document and you will be able to find out how the main hydraulic elements are designated.
Designations of hydraulic elements on diagrams
Let's look at the main elements hydraulic circuits.
Pipelines
Pipelines on hydraulic diagrams shown with solid lines connecting the elements. Control lines are usually shown as a dotted line. The directions of fluid movement, if necessary, can be indicated by arrows. Lines are often indicated on hydraulic diagrams by the letter P denotes pressure line, T - drain, X - control, l - drain.
The connection of lines is shown by a dot, and if the lines intersect on the diagram, but are not connected, the intersection is indicated by an arc.
Tank
A hydraulic tank is an important element that stores hydraulic fluid. A tank connected to the atmosphere is shown on the hydraulic diagram as follows.
A closed tank or container, such as a hydraulic accumulator, is shown as a closed loop.
Shown below hydraulic drive diagram, allowing you to move the hydraulic cylinder rod, with the ability to charge the hydraulic accumulator.
Hydraulic and pneumatic diagrams help you understand how hydraulic and pneumatic equipment. Individual elements of hydraulic and pneumatic circuits have their own symbols. Below are the symbols that you will encounter on hydraulic diagrams.
| Work line. | |
| Control line. | |
| Drain line. | |
| Flexible line. | |
| Electrical wire. | |
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Inside the interrupted line, the devices are built into one unit. |
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| Shaft, lever, rod, piston rod. | |
| Connecting lines. | |
| Crossing lines. | |
| Direction of oil flow in the hydraulic circuit. | |
| Direction of air flow in a pneumatic circuit. | |
| Direction. | |
| Direction of rotation. | |
| Direction of flow in the valve. The perpendicular shows the lateral movement of the arrow. | |
| Indication of the possibility of adjustment. | |
| Spring. | |
| Adjustable spring. |
Pumps and compressors.
designation on hydraulic diagrams.
Pressure control.
Pressure controls.
Designation of different types of valves that control hydraulic pressure on hydraulic diagrams. Designation of hydraulic motors.
Valves.
Identification of valves on hydraulic diagrams.
| A valve is indicated by a square or series of squares when each the square indicates one operating position of the valve. |
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| Directional control valves (eg boom control) | |
| The lines are connected to the neutral position square. Marking of holes in valves: P = pressure from pump T – to the tank A, B, C... - working lines X,YZ... - control pressure a,b.c... - electrical control connections |
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One way to flow. |
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| Two paths for flow. | |
| One flow path, two connections closed. | |
| Two flow paths, one connection closed. | |
| In the following examples, the first digit indicates the number of connections. Second the number indicates the number of working positions. |
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| 3/2 control valve; controlled by pressure from both sides. | |
| 4/3 control valve; lever control, return spring. |
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| 6/3 control valve | |
| Stop valve(for example a ball valve). | |
| shut-off valves. | |
| Pressure limiting valve. The valve opens a flow channel into the tank or into the air, when the valve inlet pressure exceeds the closing pressure. (Hydraulic to the left, pneumatic to the right). |
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| Pressure reducing valve, no pressure release. When the inlet pressure changes, the outlet pressure remains the same. But the input pressure through reduction should be above outlet pressure |
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Hydraulic motors - designation on hydraulic diagrams.
Reducing and check valves, flow regulators - designation on hydraulic diagrams.
Filters, tanks, water separators and other elements on hydraulic circuits.
Description
Designation on the diagram
Basic lines
Pilot lines
Drain lines
Boundary lines
Electric lines
Direction of fluid movement (hydraulics)
Direction of gas movement (pneumatics)
Direction of rotation
Crossing lines
Connecting lines
Quick Coupling
Flexible line
Variable Component
Components with pressure compensator
Open type tank (atmospheric pressure in the tank) (Reservoir Vented)
Overpressure tank (closed type) (Reservoir Pressurized)
Tank drain line (above liquid level)
Tank drain line (below liquid level)
Electric Motor
Spring Loaded accumulator
Gas Charged accumulator
Heater
Heat exchanger (cooler)
Filter
Pressure gauge
Thermometer
Flow meter
Pressure relief valve ("breather") (Vented Manifold)
Fixed Displacement Pump
Constant volume pump (unregulated) reversible
Variable Displacement Pump
Variable volume pump (adjustable) reversible
Constant volume hydraulic motor (non-adjustable)
Hydraulic motor of constant volume (unregulated) reversible
Variable displacement hydraulic motor (adjustable)
Variable displacement hydraulic motor (adjustable) reversible
Combined pump and motor
Combined pump and motor
Hydrostatic transmission
Hydraulic cylinders
Single acting cylinder
Double Acting Cylinder
Double acting cylinder with double end rock(Synchronous)(Double actin, Double end rock)
Hydraulic cylinder with damper (Cushion)
Hydraulic cylinder with adjustable damper (Adjustable Cushion)
Double-acting differential hydraulic cylinder
Valves
Check valve
Controlled check valve
Shuttle valve
Throttle valve-fixed output
Throttle valve-adjustable output
Adjustable throttle with check valve
Flow dividing valve
Normally closed valve
Normally open valve
Pressure limiting valve, Fixed
Pressure limiting valve, Variable
Pilot operated, External drain line
Pilot operated, internal drain line
Pressure Relief Valve(safety valve)
Pressure Switch
Manual Shut-Off valve
Control type
Spring
Spring return
Manual control
Push Button
Lever (Push-Pull Lever)
Pedal or Treadle
Mechanical control
Detent
Pilot Pressure
Pilot Pressure - Internal Supply
Hydraulic operated
Pneumatic operated
Pneumatic-hydraulic operated
Solenoid
Motor operated
Servo Motor
Pressure Compensated
Directional valves
2 position distributor
3 position distributor
2-position valve without fixing
2-position, with two extreme positions and neutral
2-position, 2-line
2-position, 3-line
3-position, 4-line
Mechanical feed back valve
hydrostat.ru
Graphic symbols of pipeline fittings | Pipeline accessories
Rating: / 0Conventional (graphic) images of pipeline fittings are used when drawing up a detailed network, in which all the nodes and components of the water supply network - pipeline shut-off and control valves and fittings, etc. are depicted schematically (not to scale) with symbols. Designations of pipeline fittings according to the TsKBA system and others are given HERE.
Detailing of a water supply network is used for the installation of sections of pipelines, fittings and fittings, and other equipment. Based on the details, a specification of fittings and fittings required for the network device is drawn up.
Below are the main symbols of pipeline fittings:
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Armature |
Designation |
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Gate valve (gate) through passage Angle shut-off valve |
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Ball valve through passage Angle ball valve |
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Regulating valve (gate) Angle control valve |
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Three-way valve |
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Straight-through safety valve Angle safety valve |
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Pressure regulator "towards you" Pressure regulator "after itself" |
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Non-return valve, straight through Receiving rotary check valve (flap) with mesh |
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Throttle valve |
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Reducing valve |
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Quick opening valve (NO) Quick closing valve (NC) |
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types, device, principle of operation, installation
A check valve allows fluid to flow through a pipeline in one direction and prevents it from flowing in the opposite direction. It is an important component of any water supply, heating, sewerage and industrial systems. technological installations. It is also used in anti-leakage systems in washing machines and dishwashers. Locking devices have a variety of designs, each of which has its own advantages and scope. Their common feature is that the valve opens when a certain pressure is reached and closes when the pressure drops below the set value.
Check valve appearance 
Internal organization check valve What does a water check valve for a pump consist of and how does it work?
The water check valve consists of the following parts:
- housings;
- spool - a movable executive body, which in turn is assembled from a pusher, spool plates and an elastic gasket sandwiched between them;
- sealing gasket;
- springs (except for gravity-type lifting devices).
The design of a water check valve varies depending on its type.
The body is most often made of brass - this material is not susceptible to corrosion and the effects of chemically active substances contained in water in the form of a solution, it is strong and durable.
Sometimes on outside Chrome or nickel coating is applied using the galvanic method. The spool parts are also made of brass or durable plastic. The water check valve gasket is most often rubber or silicone. And finally, the spring is made of stainless steel with a high elasticity coefficient.
How does a check valve work?
The principle of operation of a check valve is that the spool moves along the pusher (rod) and can occupy extreme positions in the spool chamber. The forward pressure of water compresses the spring and presses the plates into the open position. Water passes through the valve. If the pressure drops, the spring presses the plates and the gasket sandwiched between them to the seat and closes it. The principle of operation of a lift-type check valve is almost the same, only the role of the spring is played by the mass of the spool and the force of attraction.
Types of check valves
Depending on the type of locking element, the following types of check valves are distinguished:
- Lifting type. The disc check valve plate moves up and down. After applying pressure in the working direction, the valve opens, and when the pressure drops or the direction of fluid movement changes, it closes under the action of a spring or its own weight.
- Turning. A non-return valve is a flap that rotates and opens under fluid pressure, and closes with spring force when the pressure drops.
- Ball. The flow is blocked by a ball pressed against the valve seat by a return spring. The pressure of the liquid pushes the ball away from the seat, opening a passage for water.
- Wafer. It can be a disk - the design is similar to a lifting one, but the plate moves along the flow axis, and a double-leaf - the damper consists of two flaps that fold towards each other. The double-leaf design has minimal resistance to flow when open.
Based on the material used, check valves can be divided into the following types:
- Brass - reliable and wear-resistant, most often used in everyday life.
- Cast iron - inexpensive, but susceptible to rust, used only on main pipes.
- Stainless steel is the highest quality and most reliable, but also the most expensive. Used in the most critical systems.
Depending on the method of fastening the water return valve, there are:
- Coupled - the water valve is connected to the pipe break using two threaded couplings. Most common in household systems Oh.
- Flanged - the gate valve is connected using flanged connections. Mainly used for cast iron devices on large pipes.
- Wafer type - the shut-off valve is located between two flanges, which are tightened together with through pins. Also used on main pipelines.
Valve installation locations
In domestic water supply and heating systems there are many places where it is necessary to install a check valve:
- At the entrance to the apartment there is a centralized hot water supply.
- After the meter to protect it from water hammer.
- Before pumping station individual water supply systems - to stop water leakage from pipes after a power outage.
- At the end of a water intake hose lowered into a well or borehole, or after a submersible pump - to prevent water from draining when the pump stops.
- At the electrical or gas water heater- to avoid the release of heated and expanded water into the cold main.
- In the leakage protection system of washing machines and dishwashers.
These are the most common installation locations. If necessary, such a water valve is installed in all places where it is necessary to ensure water flow strictly in one direction.
How to make the right choice
To select a check valve that will work long and reliably in harmony with other elements of your water supply or heating system, you need to pay attention to the following points:
- Purpose. The type of device selected must match it. For example, lift-type valves with gravity action can be installed strictly in the position provided for by the design, so that the stroke of the rod is perpendicular to the surface of the earth.
- Connection method. It is selected simultaneously with the design of the connectors to which the valve will be connected, in order to avoid a clutter of unnecessary adapters. For domestic systems, coupling connections are usually used.
- Size. Must exactly match the diameter of the pipeline. The use of a smaller diameter valve connected through adapters will reduce the reliability of the design and create increased flow resistance.
- Material. For hot liquids, it is better to use brass or stainless steel, since polypropylene has high temperatures the resource is noticeably reduced.
It is difficult for a novice home craftsman to take into account all the nuances, so if in doubt, do not hesitate to consult with an experienced engineer.
Design of different types of valves
The selection and installation of a check valve for water depends on its design features. The water valve can be of the following types:
Spring coupling check valve
The device body consists of two cylinders united by a threaded connection. The spool consists of a plastic pusher, a pair of plates and an elastic gasket. The normal position of the valve is closed; when liquid pressure is applied and it reaches the specified value, it presses the spring and the water valve opens. When the pressure drops, the spring returns the spool to its place, closing the valve.
Rotary paddle
The spool in this version is made not axial, but rotary, and the axis is located above the clearance of the valve. When fluid pressure is applied, it presses the valve and the valve opens. When the pressure drops, the damper, under the influence of gravity or a return spring, lowers and closes the gap. When installing such a device, it is important to observe the “top” marking and the maximum possible slope specified in the documentation. In large devices, when the damper is returned, a powerful impact occurs on the saddle, which can lead to water hammer and even failure of the device. To prevent this, the design has to be complicated and shock-damping elements added. The design makes it possible to create valves of large diameters that are little sensitive to the presence of suspensions and other inclusions in the liquid.
Ball model
The mode of operation and device are very similar to a poppet spring valve. The role of the locking part is played by a ball pressed against the seat by a spring. It is mainly used for small diameter pipes in household plumbing systems. Such a check valve with an equal cross-section has larger external dimensions than a poppet valve.
Lifting type product
In this case, the spool rod is placed vertically; under water pressure, the spool rises, opening the valve. When the pressure decreases, the rod lowers and the valve closes. There is a limitation on the installation of such devices - it can only be designed on horizontally located pipes. An important advantage of such designs is the ability to repair the spool without removing the entire body. The downside is the increased requirements for liquid purity.
Check valves for submersible pumps
To organize uninterrupted water supply in private homes using a submersible pump, it is especially important to install a check valve immediately behind the pump. This will prevent water from flowing back into the well when the pump is turned off and will eliminate the need to refill the system with water each time.
With a well of great depth, a sufficient diameter of the pipeline and the distance of the well from the house, we can talk about tens of liters of water. In many models of submersible pumps, such a valve is installed at the factory. If it is not there, then, as a rule, they choose a device made of brass with axial movement of the spool and a return spring. The clearance of the valve must be no less than the internal diameter of the pipeline so as not to create additional resistance to flow.
Check valve installation rules
It is not enough to select the optimal device model; you also need to install it correctly.
Incorrect installation of the valve may result in the need for repair or replacement, which can be quite time-consuming, especially if it is installed in a well.
- If an arrow is drawn or stamped on the body, then it must be installed strictly with the arrow pointing upward, even despite the presence of a return spring.
- If the depth of the well or well (more precisely, the distance to the water surface) is small, then a check valve is placed directly at the entrance to the pressure apparatus.
- In cases where the well depth is more than 8 m, it is better to install the device at the water intake, supplementing it with a mechanical coarse filter.
- When using a submersible pump, a valve must be installed at its outlet.
- At long distance It is better to install two valves up to the well - at the outlet of the pressure device and at the entrance to the house.
It is impossible to provide for all options, so before starting installation you should show the diagram of your water supply or heating system to a qualified and experienced plumbing engineer.
How to install check valves for pumping stations
A check valve for joint operation with a pumping station should be selected at the design stage. In some pump models, such valves are included in the design; for others, there are several rules:
- For vacuum type (suction) pumps, the valve is mounted at the pump outlet, before the hydraulic accumulator.
- If the well is deep and at a large distance from the well on the surface, an additional device should be installed at the water intake.
- For pressure pumps lowered into the well, the valve is mounted on the outlet pipe.
In addition, during installation, the flow direction indicated on the housing must be strictly observed and all connections must be carefully sealed.
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stankiexpert.ru
what is it for, principle of operation, types
A mandatory element of equipping autonomous water supply systems in dachas and country houses is a check valve. That's exactly what technical device, which may have different design, ensures the movement of liquid through the pipeline in the required direction. Check valves installed in the system autonomous water supply, reliably protect it from the consequences of emergency situations. Referring to direct-acting valves, check valves operate automatically using the energy of the working medium transported through the pipeline system.
Purpose and principle of operation
The main function that a water check valve performs is that it protects the water supply system from critical flow parameters of the liquid transported through the pipeline. The most common cause critical situations is a stop pumping unit, which can lead to a number of negative phenomena - draining water from the pipeline back into the well, spinning the pump impeller in the opposite direction and, accordingly, breakdown.
The installation of a check valve on the water allows you to protect the water supply system from the listed negative phenomena. In addition, the water check valve prevents the consequences caused by water hammer. The use of check valves in pipeline systems makes their operation more efficient and also ensures correct functioning pumping equipment with which such systems are equipped.
The principle of operation of the check valve is quite simple and is as follows.
- The flow of water entering such a device under a certain pressure acts on the locking element and presses the spring, with the help of which this element is kept closed.
- After the spring is compressed and the shut-off element is opened, water begins to move freely through the check valve in the required direction.
- If the pressure level of the working fluid flow in the pipeline drops or water begins to move in the wrong direction, the spring mechanism of the valve returns the shut-off element to the closed state.
By acting in this way, the check valve prevents the formation of unwanted backflow in the piping system.
When choosing a valve model installed on a water supply system, it is important to know regulatory requirements, which manufacturers of pumping equipment require for such devices. The technical parameters by which a check valve for water is selected in accordance with these requirements are:
- working, test and nominal closing pressure;
- diameter of the landing part;
- conditional capacity;
- tightness class.
Information on what technical requirements a water check valve must meet is usually contained in the documentation for the pumping equipment.
To equip domestic water supply systems, spring-type check valves are used, diameter conditional passage falls within the range of 15–50 mm. Despite their compact size, such devices demonstrate high throughput, ensure reliable operation of the pipeline, low noise and vibration levels in the pipeline system on which they are installed.
Another positive factor of using check valves in a water supply system is that they help reduce the pressure created by the water pump by 0.25–0.5 Atm. In this regard, a check valve for water allows you to reduce the load both on individual elements of pipeline equipment and on the entire water supply system as a whole.
Design features
One of the most common materials used to make the body of water return valves is brass. Choice of this material is not accidental: this alloy demonstrates exceptionally high resistance to chemically aggressive substances that may be present in water transported through a pipeline in a dissolved or suspended state. Such substances, in particular, include mineral salts, sulfur, oxygen, manganese, iron compounds, etc. The outer surface of the valves, which during their operation is also exposed to negative factors, is often protected with a special coating applied by the galvanic method.
The check valve device requires the presence of a spool, for the manufacture of which brass or durable plastic can also be used. The sealing gasket present in the check valve design can be rubber or silicone. To manufacture an important element of the locking mechanism - the spring - stainless steel is usually used.
So, if we talk about structural elements spring check valve, then this device comprises:
- composite type housings, the elements of which are connected to each other by means of threads;
- a locking mechanism, the design of which includes two movable spool plates mounted on a special rod and a sealing gasket;
- a spring installed between the spool plates and the seat at the outlet of the through hole.
The principle of operation of a spring check valve is also quite simple.
- The flow of water entering the check valve under the required pressure acts on the spool and depresses the spring.
- When the spring is compressed, the spool moves along the rod, opening the passage hole and allowing the fluid flow to move freely through the device.
- When the pressure of the water flow in the pipeline on which the check valve is installed drops, or in cases when such a flow begins to move in the wrong direction, the spring returns the spool to its seat, closing the throughput hole of the device.
Thus, the operation scheme of the check valve is quite simple, but nevertheless ensures high reliability of such devices and the efficiency of their use in pipeline systems.
Main types
Having understood how a check valve installed in a water supply system works, you should also understand how to choose it correctly. The modern market offers various types of check valve devices, the design, material of manufacture and operation scheme of which can vary significantly.
Sleeve type spring check valve
The body of this type of valve consists of two cylindrical elements connected to each other using threads. The locking mechanism includes a plastic rod, upper and lower spool plates. The position of the elements of the locking mechanism in the closed state, as well as their opening at the moment when the pressure of the water flow reaches the required level, is ensured by a spring. The component elements of the housing are connected to each other using a sealing gasket.
Spring loaded check valve with brass spool and spherical spool chamber
The distinctive features of this type of shutter are easy to see even in the photo. The brass body of such a valve in its middle part, where the spool chamber is located, has a spherical shape. This design feature allows you to increase the volume of the spool chamber and, accordingly, the throughput of the check valve. The locking mechanism of this type of water valve, which is based on a brass spool, works on the same principle as in any other type of valve device.
Combined spring type check valve with drain and air vent
Many of those who decide to independently install a pipeline system often have a question about why they need a check valve equipped with drainage and air vent systems. The use of check valves of this type (especially for equipping pipelines through which hot working fluids are transported) makes it possible to simplify the process of installation and maintenance of such systems, increase their reliability, and reduce the total hydraulic pressure, reduce the number of installation connections.
On the body of this type of valve, which can be seen even in the photo, there are two pipes, one of which is used for mounting the air vent, and the second performs the function drainage element. The branch pipe for the air vent, on the inner surface of which is threaded, is located on the device body above the spool chamber (its receiving part). Such a pipe is needed to bleed air from the pipeline system, for which a Mayevsky valve is additionally used. The purpose of the pipe, which is located on the opposite side of the body - at the outlet of the valve, is to drain the liquid accumulated after the valve device from the system.
If you install a horizontal check valve, its air outlet pipe can be used to mount a pressure gauge. If you place a combined check valve on a pipeline vertically, then its drainage pipe can be used to drain water accumulated after such a device, and the air vent pipe can be used to remove it from the part of the pipeline that is located before the check valve. air jams. That is why, when deciding how to install a combined type check valve, you should clearly understand what functions such a valve should perform.
Spring valves with polypropylene body
Check valves, the body of which is made of polypropylene, even if you look at the photos of such devices, look very similar to oblique bends. These types of check valves, for installation of which the polyfusion welding method is used, are installed on pipelines also made of polypropylene. An additional oblique outlet in the design of valves of this type is necessary to accommodate the elements of the locking mechanism, which makes it easier Maintenance such a device. Thereby constructive solution It is not difficult to carry out maintenance and repair of a check valve of this type - it is enough to remove the elements of the locking mechanism from its additional outlet without violating the integrity of the device body and the tightness of its installation in the pipeline system.
Other types of check valves
In pipeline systems designed to transport water, other types of check valves can be installed.
- The check valve is equipped with a special shut-off element - a spring-loaded petal. The big disadvantage of valves of this type is that when they operate, significant shock loads are created. This has a negative impact on technical condition the valve itself, and can also cause water hammer in the pipeline system.
- Double-leaf check valve devices are compact in size and light in weight.
- The lift coupling check valve includes a spool as a shut-off element that moves freely along the vertical axis. The operation of the locking mechanism can be based on the gravitational principle, when the spool returns to the closed state under the influence of its own weight. A spring can also be used for this purpose. If you decide to install a gravity check valve on the pipeline, keep in mind that such a device can only be installed on vertical sections of the system. Meanwhile, the gravity valve is characterized by a simple design, while demonstrating high reliability during operation.
- There are check valves whose closing element is a spring-loaded metal ball. The surface of such a ball can be additionally covered with a layer of rubber.
When deciding which check valve is better and whether an expensive valve of a more complex design is needed in the pipeline system, you should first get acquainted with the technical characteristics of such a device and compare them with the operating parameters of the pipeline system. The main purpose of a check valve, as mentioned above, is to pass water through the pipeline in the desired direction and prevent the flow of liquid from moving in the opposite direction. In this regard, you should choose a check valve for water based on the pressure under which the water flow moves in the pipeline. Naturally, it is necessary to take into account the diameter of the pipes on which such a valve should be installed.
When installing a pipeline, you should also keep in mind that you can install a check valve in various ways. On large-diameter pipes, flange and wafer-type check valves are installed, and on small-diameter pipes, coupling valve devices are installed. The welded method of installing check valves is used mainly for installation on polypropylene and metal-plastic pipes.
If you choose the right check valve and the method of its installation, such a device will not only last for a long time, but will also ensure the correct operation of the entire pipeline system.
How to install correctly
Having understood the question of why a check valve is needed and its role in the pipeline system, you should also study the rules for installing it on an already operating or newly created pipeline. Such devices are mounted on various elements of pipeline systems:
- on pipelines of autonomous and centralized water supply;
- on suction lines served by deep and surface pumps;
- in front of boilers, cylinders and water flow meters.
If you are interested in check valves that can be installed in both vertical and horizontal positions, choose spring models rather than gravity ones. You can find out in which direction the water flow should move through the valve by looking at the special arrow marked on the body of the device. When installing coupling-type check valves, be sure to use FUM tape for good sealing. In addition, we should not forget that check valves need regular maintenance, therefore they must be installed in accessible places in the pipeline.
When installing a check valve on the suction line of a submersible pump, care should be taken to install a coarse filter in front of such a device, which will prevent it from getting into inner part devices for mechanical impurities contained in underground water. A perforated or mesh cage can also be used as such a filter, into which a check valve installed at the inlet end of the suction line of a submersible pump is placed.
When installing a check valve on an already operating pipeline, you must first disconnect the system from the water supply and only then install the shutter device.
How to make your own check valve
The simple design of the check valve allows you to make it yourself if necessary.
To solve this problem you will need following materials and tools:
- tee with internal thread, which will serve as a housing;
- coupling with thread on outer surface– homemade check valve seat;
- rigid spring made of steel wire;
- a steel ball, the diameter of which should be slightly smaller than the diameter of the hole in the tee;
- a steel threaded plug that will serve as a stop for the spring;
- a standard set of plumbing tools and FUM sealing tape.
Pipeline elements designations on diagrams
Symbols for hardware and technological diagrams
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Name |
Designation |
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I. Pipeline elements |
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1. Pipeline ( general purpose) 2. Pipeline connection 3. Crossing of pipelines (without connection) (GOST 2.784-70) 4. Flexible pipeline, hose (GOST 2.784–70) |
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5. Detachable connection of pipeline elements: 5.1. General designation 5.2. Flanged 5.3. Threaded fitting 5.4. Coupling threaded 6. End of the pipeline for detachable connection: 6.1. General designation 6.2. Flanged 6.3. Threaded fitting 6.4. Coupling threaded Designations on technological diagrams. |
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Designations on technological diagrams: 7. End of the pipeline with a plug (plug): 7.1. General designation 7.2. Flanged 7.3. Threaded |
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II. Fittings - Symbols on technological diagrams. |
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8. Shut-off valve (valve) (GOST 2.785-70) 8.1. Passage 8.2. Angular 9. Three-way valve (valve) (GOST 2.785–70) |
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10. Check valve (non-return). Movement of working fluid from a white triangle to a black one (GOST 2.785-70) 11. Safety valve (GOST 2.785–70) |
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| Symbol on the diagram. 12. Throttle valve (GOST 2.785-70) 13. Reducing valve (movement from left to right) (GOST 2.785-70) 14. Automatic air valve (plunger) (GOST 2.785–70) |
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15. Air intake from the atmosphere (GOST 2.780-68) 16. Spill neck, filling fitting (GOST 2.780–68) |
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17. Connection device to other systems (testing, flushing, transport, etc.) (GOST 2.780-68) 18. Gate valve (GOST 2.785–70) Symbol on the diagram. |
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19. Rotary valve (GOST 2.785-70) 20. Crane (GOST 2.785–70) |
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21. Angle valve (GOST 2.785-70) 22. Three-way valve (GOST 2.785-70) 23. Four-way valve (GOST 2.785–70) |
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Designation on the diagram. 24. End valve (GOST 2.785-70) 25. Laboratory tap (GOST 2.785–70) |
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26. Fire valve (GOST 2.785-70) 27. Nozzle (GOST 2.780–68) |
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28.Aspiration device (local exhaust) (GOST 2.786–70) |
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29. Ventilation damper (GOST 2.786-70) 30. Gate (GOST 2.786–70) Designation on the diagram. |
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31. Automatic check valve in explosive design (ventilation) (GOST 2.786-70) 32. Fire retardant valve (ventilation) (GOST 2.786-70) 33. Discharge into sewer |
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34. Condensate drain |
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Designation of elements of hydraulic and pneumatic circuits
Hydraulic and pneumatic diagrams help you understand how hydraulic and pneumatic equipment functions. Individual elements of hydraulic and pneumatic circuits have their own symbols. Below are the symbols that you will encounter on hydraulic diagrams.
Pumps and compressors.
designation on hydraulic diagrams.
Pressure control.
Pressure controls.
Designation of different types of valves that control hydraulic pressure on hydraulic diagrams. Designation of hydraulic motors.
Valves.
Identification of valves on hydraulic diagrams.
Hydraulic motors - designation on hydraulic diagrams.
Reducing and check valves, flow regulators - designation on hydraulic diagrams.
Filters, tanks, water separators and other elements on hydraulic circuits.
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Check valve - purpose, design and principle of operation
Purpose of the check valve
Purpose of the check valve
The check valve is designed to freely pass the flow of working fluid in one direction and block it in the opposite direction. These valves use a ball or cone valve as a closing element, interacting with the seat so that there is no leakage of fluid.
The design of check valves is shown in (Fig. 1).
A linear check valve (Fig. 1 a) has a hexagonal body 1 containing a shutter 2, a spring 3, a support washer 4 and a locking ring 5. When liquid is supplied to the connecting hole “A”, it presses the shutter http://www. promarmatura.ua/zatvory-diskovye from the seat and through the slot formed by the bolt and the edge of the bore in the body, and the radial drillings “B” and the central bore in the body of the bolt goes to the outlet hole “B”. When liquid is supplied to hole “B”, the flow becomes blocked.
The design of the check valve is butt-type (Fig. 1 b) the diverter valve is made at an angle of 90 degrees to the axis of the valve, and both connecting holes are located on the lower mounting plane.
The built-in valve (Fig. 1c) contains a sleeve 1, a valve 2, a spring 3, an adapter sleeve 4 and a flange 5. The sleeve and sleeve are placed in a socket, which is made in the body part where the valve is to be built. Sealing on the outer surface of the sleeve and bushing is carried out using rubber O-rings and protective washers made of plastic.
Check valve operation
The operation of the check valve is as follows: when liquid is supplied to hole “A”, the valve shutter rises above the seat, overcoming the force of the return spring. The fluid pressure drop across the valve depends on the fluid flow through it, and the pressure at which the valve opens, allowing minimum consumption, depends only on the spring force and ranges from 0.05 to 0.3 MPa (from 0.5 to 3 kgf/cm2).
This article shows the most commonly used symbols of elements on hydraulic diagrams of metal-cutting machines. Images of elements of various hydraulic circuits and their descriptions are provided.
In the drawings of hydraulic diagrams, normalized equipment and working bodies are depicted by symbols, and lines are represented by lines. Special devices are depicted semi-constructively.
1. Introduction. Hydraulic drive composition
Semi-constructive (a) and schematic (b) representation of the hydraulic drive
In its most general form, a hydraulic drive consists of a source of hydraulic energy - a pump, a hydraulic motor and a connecting line (pipeline).
On the hydraulic diagram Fig. 1.4 semi-structurally (a) and schematically (b) shows the simplest hydraulic drive, in which pump 2, driven by electric motor 11, sucks up working fluid from tank 1 and through filter 4 supplies it to the hydraulic system, and the maximum pressure is limited by the adjustable force of the spring of safety valve 3 (controlled pressure gauge 10). To avoid accelerated wear or failure, the relief valve setting pressure should not be higher than the pump's rated pressure.
Depending on the position of the distributor handle 5, the working fluid through pipelines (hydraulic lines) 6 enters one of the chambers (piston or rod) of the cylinder 7, forcing its piston to move along with the rod and working body 8 at a speed v, and the liquid from the opposite chamber through the distributor 5 and adjustable resistance (throttle) 9 is forced into the tank.
When the throttle is fully open and there is a slight load on the working body, all the working fluid supplied by the pump enters the cylinder, the movement speed is maximum, and the value of the working pressure depends on the losses in the filter 4, devices 5 and 9, cylinder 7 and hydraulic lines 6. Closing the throttle 9, You can reduce the speed until the working body stops completely. In this case (as well as when the piston stops against the cylinder cover or the load on the working element increases excessively), the pressure in the hydraulic system increases, the safety valve ball 3, compressing the spring, moves away from the seat and the working fluid supplied by the pump (pump supply) is partially or completely bypassed through safety valve into the tank at maximum operating pressure.
During prolonged operation in bypass mode, due to large power losses, the working fluid in the tank quickly heats up.
The following symbols are presented on the hydraulic diagram:
- source of hydraulic energy -- pump 2;
- hydraulic motor- cylinder 7;
- guide hydraulic equipment- distributor 5;
- regulating hydraulic equipment- valve 3 and throttle 9;
- control devices - pressure gauge 10;
- working fluid reservoir- tank 1;
- working environment conditioner- filter 4;
- pipelines - 6.
Hydraulic drives of stationary machines are classified according to pressure, method of regulation, type of circulation, control and monitoring methods.
2. Composition of a hydraulic drive using the example of the power head of a machine tool
Hydraulic system power head of the aggregate machine
Depending on the method of depicting mechanisms and equipment on circuit diagrams, they can be semi-constructive, complete or transitional.
The hydraulic system of any option has at least two main lines - pressure and drain. Purpose routes are connected to them, which connect hydraulic motors of one or another action to the mains. There are routes: initial, free movement, precise movement, unregulated movements, control and blocking.
In Fig. 244 shows the semi-constructive, complete and transitional diagrams of the power head of an aggregate machine tool, which performs three transitions during an operating cycle: fast approach, working stroke and fast retraction. In the semi-constructive diagram (Fig. 244, a) during the “Fast approach” transition, both spools are shifted by pushing electromagnets: the main spool 1 to the right, and the spool 2 rapid strokes to the left. In this position, oil from the pump through the first left neck of spool 1 enters the extra-rod cavity of cylinder 5, and from the opposite cavity of the same cylinder through the neck of spool 2 and the second neck of spool 1 is sent to the tank.
During the “Power stroke” transition, the electromagnet of spool 2 is turned off, which forces the oil from the rod cavity of cylinder 3 to flow to drain through the speed regulator 4 and then through the third journal of spool 1 into the tank.
During the “Fast withdrawal” transition, the electromagnet of spool 1 is turned off, and the electromagnet of spool 2 is turned on again, and this changes the direction of oil flow: from the pump through the second journal of spool 1 into the rod cavity of the cylinder, and from the opposite cavity through the first journal of spool 1 into the tank. In the “Stop” position, both electromagnets are turned off, the spools move to the position shown in the diagram, and the pressure line from the pump through the second neck of spool 1, the neck of spool 2 and the annular recess around the rightmost drum of spool 1 is connected to the tank.
Full schematic diagram(Fig. 244, b) all elements of the hydraulic system have designations similar to the semi-structural diagram, therefore the above description of the operation of the hydraulic drive can be used in this case. Comparing the diagrams, you can see that the design of the second diagram is simpler, and, in addition, it clearly shows the function of the spools in their different positions.
The transition diagrams (Fig. 244, e) show the same elements, and, in addition, the signs “+” and “-” and arrows of various lengths make it possible to clarify the actions of the electromagnets and the power cylinder. In fact, from consideration of diagram 1 it follows that both electromagnets are connected, and oil from the pressure line NM through one journal of spool 1 enters the extra-rod cavity of cylinder 3, and is stripped from the opposite cavity through the journals of spools 2 and 1. The piston moves in the direction " Rod forward" accelerated (long arrow).
From diagram II it follows that in this transition only spool 1 works, which remains in the same position, and turning off the high-speed spool 2 activates speed controller 4, consisting of a pressure reducing valve and a throttle. The piston at this transition moves in the same direction, but at operating speed (short arrow). From diagram III it can be seen that spool 2 is turned on again, and spool 1 is turned off, but takes part in this transition. With this switching of the spools, oil from the LM line through the journals of both spools enters the rod cavity of the cylinder, and from the opposite cavity is drained through the second journal of spool 1. The piston changes its speed and direction. From diagram IV it follows that both spools are turned off, and the pressure line is connected to the tank through their journals, and therefore, in this position, even when the pump is running, the hydraulic drive is turned off.
3. Symbols of hydraulic drive elements on hydraulic diagrams
Conventional graphic symbols serve to functionally represent hydraulic drive elements and consist of one or more basic and functional symbols. In accordance with DIN ISO 1219-91, GOST 2.781-96 and 2.782-96 standards, the following basic symbols are used:
- continuous line- main hydraulic line (suction, pressure, drain), electrical line;
- dotted line- control line, drainage, indication of intermediate position;
- dash-dotted line- combining several components into a single unit;
- double line- mechanical connection (shaft, rod, lever, rod);
- circle- pump or hydraulic motor, measuring device (pressure gauge, etc.), check valve, swivel joint, hinge, roller (with a point in the center);
- semicircle- rotary hydraulic motor;
- square (with joint perpendicular to sides)- hydraulic apparatus, drive unit (except for the electric motor);
- square (with connection at corners)- working environment conditioner (filter, heat exchanger, lubricator);
- rectangle- hydraulic cylinder, hydraulic device, adjustment element;
- open top rectangle- tank;
- oval- battery, gas cylinder, supercharged tank.
Functional symbols include triangles (black for hydraulics, white for pneumatics), various arrows, lines, springs, arcs (for throttles), and the letter M for electric motors.
Hydraulic distributor symbols
In the designation of hydraulic valves, several squares are located nearby (in accordance with the number of positions, i.e. fixed positions of the spool relative to the body), and hydraulic lines are connected to one of the positions (initial): P - pressure, T - drain, A and B - for connection hydraulic motor. The number of hydraulic lines can be different: P, T, A and B - for four-line devices; P, T and A - for three-line; P, T1 (TA), T2 (TV), A and B - for five-line, etc.
Examples of symbols for hydraulic valves
In Fig. 1.6, a shows the symbol of a four-line three-position device (4/3 hydraulic valve) with electrical control from two pushing electromagnets (Y1 and Y2) and spring return to the original position 0, in which all lines are locked. When the Y1 electromagnet is turned on, the spool moves to the right, and you can determine the option of connecting the lines by mentally moving the square corresponding to position a to the place of the square at position 0. As you can see, lines P-B and A-T are connected. When the electromagnet Y2 is turned on in position b, connection R-A and V-T. If it is necessary to show the connection of lines in intermediate positions at the moment of switching from one position to another, dotted squares are added between the main positions (Fig. 1.6, b). In hydraulic valves controlled, for example from a proportional electromagnet Y3 (Fig. 1.6, c), many different intermediate positions are possible, and two horizontal lines are added to the symbol. Conventional graphic symbols of the main elements of the hydraulic drive are given in table. 1.1.
Example of a hydraulic circuit
Letter position designations of the main elements of the hydraulic circuit:
- A- Device (general designation)
- AK- Hydraulic accumulator (pneumatic accumulator)
- AT- Heat exchanger
- B- Hydraulic tank
- VD- Moisture separator
- VN- Valve
- VT- Hydraulic displacer
- G- Pneumatic silencer
- D- Hydraulic motor (pneumatic motor) rotary
- DP- Flow divider
- DR- Hydro throttle (pneumatic throttle)
- ZM- Hydraulic lock (pneumatic lock)
- TO- Hydrovalve (pneumatic valve)
- HF- Hydraulic valve (pneumatic valve) time delay
- KD- Hydrovalve (pneumatic valve) pressure
- KO- Hydrovalve (pneumatic valve) return
- KP- Hydraulic valve (pneumatic valve) safety
- KR- Hydrovalve (pneumatic valve) reducing
- KM- Compressor
- M- Hydraulic motor (pneumatic motor)
- MN- Pressure gauge
- MP- Hydrodynamic transmission
- MR- Oil sprayer
- MS- Oil can
- MF- Hydrodynamic coupling
- N- Pump
- ON- Axial piston pump
- NM- Pump-motor
- NP- Vane pump
- HP- Radial piston pump
- PG- Pneumatic-hydraulic converter
- ETC- Hydraulic converter
- R- Hydraulic distributor (pneumatic distributor)
- RD- Pressure switch
- RZ- Spool hydraulic device (pneumatic device)
- RK- Hydraulic device (pneumatic device) valve
- RP- Flow regulator
- PC- Receiver
- WITH- Separator
- JV- Flow adder
- T- Thermometer
- TR- Hydrodynamic transformer
- UV- Air venting device
- US- Power steering
- F- Filter
- C- Hydraulic cylinder (pneumatic cylinder)
For illustration on hydraulic diagrams various elements and devices use conventional and graphic symbols - All sizes of conventional graphic symbols specified in the standards can be changed proportionally.
In addition, you can use other graphic symbols - Graphic symbols are made with lines of the same thickness as the communication lines.
To simplify the diagram drawing (reducing kinks and intersections of communication lines), conventional graphic symbols can be depicted rotated by an angle multiple of 90 or 45 degrees, as well as mirrored - Elements and devices of hydraulic, pneumatic and thermal circuits are shown in their original positions (check valve closed, springs in a state of compression).
On diagrams it is allowed to place various technical data, the nature of which is determined by the purpose of the diagram - They can be located near the graphic (on the right or top) or on the free field of the diagram (preferably above the main inscription).
Near the graphic designations of elements, their alphanumeric designations are indicated, and in the free field of tables, diagrams, text instructions - The alphanumeric designation consists of letter designation(BO) and the serial number placed after the BO - BO circuits are determined by GOST 2.704-76 - For designations, capital letters of the alphabet are used, which are initial or characteristic of the name of the element - Letters and numbers in positional designations on the diagram are written in the same size font - Sequential numbers must be assigned in accordance with the sequence of arrangement of elements or devices on the diagram from top to bottom in the direction from left to right.
Technical data about the elements of the circuits must be recorded in the list of elements - In this case, the connection of the list with the conventional graphic designations of the elements should be carried out through positional designations - For simple circuits, it is allowed to place all information about the elements near the conventional graphic designations on the shelves of leader lines - The list of elements is drawn up in in the form of a table and placed on the first sheet of the diagram above the main inscription, the distance between them must be at least 12 mm - The list can also be made in the form of an independent document in A4 format.
The main inscription indicates the name of the product and the name of the document - The following data is indicated in the columns of the list: in the column - the position designation of an element, device or designation of a functional group on the diagram; in the column - the name of the 26th element in accordance with the document on the basis of which it was applied and the designation of this document - If it is necessary to indicate the technical data of the element, it is recommended to indicate them in the column.
The diagram may indicate the parameters of flows in communication lines: pressure, flow, temperature, etc., as well as parameters to be measured at control taps.
4. Symbols on hydraulic diagrams adopted in the USSR
The method of depicting lines in the hydraulic systems of machine tools is not standardized - The most convenient seems to be the following method, adopted by many organizations and used in the technical literature:
- highways connecting various devices - with thick solid lines;
- highways made inside the devices are thin solid lines;
- drainage lines - with thin dashed lines - Symbols of devices are drawn with contour solid lines of normal thickness - The connection points of the lines are indicated by a line and a dot (pos - 43, Fig - 4); intersections without connections should be marked with a contour sign (pos. 44, fig. 4).
Figure 4 shows the main symbols on hydraulic diagrams adopted in the USSR:
- general designation of an unregulated pump without specifying the type and type;
- general designation of an adjustable pump without indicating the type and type;
- double-acting, unregulated, vane (rotary vane) pump, types G12-2, G14-2;
- twin vane (rotary vane) pumps with different capacities;
- unregulated gear pump type G11-1;
- unregulated radial piston pump;
- adjustable radial piston pump type PPR, NPM, NPChM, NPD and NPS;
- pump and hydraulic motor are axial piston (with swashplate), unregulated;
- pump and hydraulic motor axial piston (with swashplate) adjustable types 11D and 11P;
- general designation of an unregulated hydraulic motor without specifying the type;
- general designation of an adjustable hydraulic motor without indicating the type;
- plunger hydraulic cylinder;
- telescopic hydraulic cylinder;
- single-acting hydraulic cylinder;
- double-acting hydraulic cylinder;
- hydraulic cylinder with double-sided rod;
- hydraulic cylinder with differential rod;
- single-acting hydraulic cylinder with piston return with spring rod;
- servomotor (torque hydraulic cylinder);
- apparatus (main symbol);
- spool types G73-2, BG73-5 controlled by an electromagnet;
- spool with manual control type G74-1;
- spool with controls from a cam type G74-2;
- check valve type G51-2;
- pressure spool type G54-1;
- pressure spool type G66-2 with check valve;
- two-way spool type G74-3 with check valve;
- safety valve type G52-1 with overflow valve;
- pressure reducing valve type G57-1 with regulator;
- four-way valve, type G71-21;
- four-way three-position valve type 2G71-21;
- three-way valve (three-channel);
- two-way valve (through);
- damper (unregulated resistance);
- choke (unregulated resistance) types G77-1, G77-3;
- throttle with regulator types G55-2, G55-3;
- general designation of the filter;
- plate filter;
- mesh filter;
- pressure switch;
- pneumatic hydraulic accumulator;
- pressure gauge;
- pipe connection;
- pipe intersections without connection;
- plug in the pipeline;
- reservoir (tank);
- drain;
- drainage.
Features and benefits of hydraulic drive
Hydraulic drive- a set of devices (which include one or more volumetric hydraulic motors) designed to drive mechanisms and machines using working fluid under pressure. Hydraulic drives are one of the most rapidly developing sub-sectors of modern mechanical engineering. Compared to other known drives (including electromechanical and pneumatic), hydraulic drives have a number of advantages. Let's look at the main ones.
- Possibility of obtaining greater strength and power with limited sizes of hydraulic motors. Thus, a hydraulic cylinder with a piston diameter of 100 mm at a pressure of 70 MPa, which can be created by a hand pump, develops a force of about 55 tons, so using special jacks you can manually lift bridges.
- High performance ensuring the required quality of transient processes. Modern hydraulic drives, for example test benches, are capable of processing a given impact with a frequency of up to several hundred hertz.
- Wide range of stepless speed control subject to good smooth movement. For example, for hydraulic motors the control range reaches 1:7000.
- Possibility of protecting the hydraulic system from overload And precise control acting forces. The force developed by a hydraulic cylinder is determined by the area of its piston and the operating pressure, the value of which is set by adjusting the safety valve and controlled by a pressure gauge. For a hydraulic motor, the amount of torque developed is proportional to the working volume ( overall dimensions hydraulic motor) and the current pressure of the working fluid.
- Obtaining linear motion using a hydraulic cylinder without kinematic transformations (an electromechanical drive usually requires a gearbox, screw or rack and pinion gear, etc.). By selecting the areas of the piston and rod chambers, it is possible to ensure a certain ratio of forward and reverse stroke speeds. An important circumstance is the ideal protection of hydraulic cylinders from external contaminants, which allows the successful operation of hydraulic drives, for example, in mining equipment, excavators and other machines operating in conditions of increased environmental pollution, and in some cases under water.
- Extensive range of control mechanisms, ranging from manual control to direct control from a personal computer, allows the optimal use of hydraulic drives to automate production processes in various fields of technology, successfully combining the exceptional power and dynamic qualities of hydraulics with the ever-expanding capabilities of microelectronics and complex control systems.
- Wide range of energy storage and recovery capabilities provide a good basis for the development of modern energy-efficient hydraulic drive mechanisms.
- Layout of hydraulic drives mainly from standardized products, mass-produced by specialized factories, provides a reduction in manufacturing costs, improved quality and reliability, ease of placement on a machine of a large number of compact hydraulic motors (hydraulic cylinders or hydraulic motors) powered by one or more pumps, and opens up wide opportunities for repair and modernization.
- Biryukov B.N. Hydraulic equipment metal-cutting machines., 1979
- Sveshnikov V.K. Machine hydraulic drives: Handbook - 6th ed. reworked and additional - St. Petersburg: Politekhnika, 2015
- Kucher A.M., Kivatitsky M.M., Pokrovsky A.A., Metal cutting machines(Album), 1972
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