Check valve for compressor: principle of operation, varieties
To ensure the correct operation of compressor equipment, various technical devices are used, among which a check valve for the compressor can be distinguished. Without this node, it is almost impossible to imagine the operation of equipment designed to compress air.
Check valves are used in many areas. Such devices most often work in tandem with any tanks or compressors. The main task of the check valve is to prevent the loss of pressure pumped into the system and limit the access of unwanted elements into the system.
In the absence of such a mechanism, the efficiency of the equipment is noticeably reduced. For example, compressors are forced to work almost non-stop, which affects not only the operational life of the equipment, but also on electricity bills.
Applications check valves:
- systems operating with the distillation of liquid media;
- gas pipelines;
- refrigeration equipment;
- plumbing equipment.
In addition to maintaining pressure in the system, check valves do not allow penetration of liquid media into the compressor. With large volumes of distillation, as well as a serious load on the equipment, it is very important to maintain the tightness of the equipment. This moment is also critical when working with gaseous compositions, especially hot ones.
in air conditioning and similar equipment, these valves perform two important functions:
- Restrict access to reverse condensation.
- Provide unhindered distillation of freon from the hot part of the evaporator to the cold.
Check valves are often used in ventilation technology both in domestic and industrial sectors. Equipment of this kind can be seen in apartments — kitchens and bathrooms, in offices, catering places, as well as on construction sites and other technical facilities.
The check valve performs the following functions:
- improves the quality of traction in complex multi-level sections;
- limits the access of cold streams from the outside;
- protects the room from the penetration of toxic environments, as well as unpleasant odors;
- in case of fires, it prevents the ingress of combustion products.
You may be interested in: check valve ventilation.
Similarly, check valves are used in plumbing and other systemswhere clipping of unwanted elements is required.
Types of equipment
On the market you can find devices of various form factors, as well as destinations. It is customary to distinguish equipment by design features, as well as by the method of installation. The choice of one or another device directly depends on the tasks assigned to it.
Structural varieties check valves:
- classic (straight);
- on flanges;
- for disassembly.
The performance of the device is also affected production material. Check valves made of metal alloys are used in industrial structures where a serious load is expected. Whereas plastic mechanisms can be seen in ordinary kitchens and bathrooms.
Regardless of the design, check valves can be:
The former can often be found in ventilation equipment. Ball valves are used in compressors, and other types in gas and plumbing lines. There are also advanced mechanisms with electromagnetic constipation.
The cost of the latter, of course, is much higher. In this case, blocking occurs not by means of a conventional spring spring, but by means of an electromagnet. But such valves are picky about distillation products and volumes, so industrial equipment manufacturers most often prefer more resistant and reliable spring counterparts.
Check valve on the compressor
This part is installed between the piston compressor cylinder and the receiver, and does not allow air to return from the storage tank back to the compression chamber after the unit has stopped.
Important! In addition, the return valve, keeping the air in the receiver, allows you to smoothly start the equipment. If this part is removed, then the air will press on the piston, and the engine will not be able to crank the crankshaft when starting.
In addition to the opposite, a safety valve must be installed on the compressor. This bypass valve is designed for emergency pressure relief if the pressure switch has not turned off the engine of the unit. The following photo shows an unloader valve, without which, for safety reasons, the compressor cannot be turned on.
Device and principle of operation
The design of the return line includes the following elements (see the figure below):
- metal case (3);
- valve (6), which closes the inlet and is equipped with guide ribs to prevent distortion;
- rubber ring (5) mounted on the top of the valve (6);
- spring (4), which presses the rubber ring to the inlet and puts on the protrusions located on the plug (1) and on the valve (6);
- a plug that has a seal in the form of a cardboard gasket (2) and allows the assembly to be disassembled for cleaning and repair.
The return, in addition to the inlet fitting, has a side outlet through which it is connected to the receiver, and 1 thin outlet for connecting the pressure switch.
check valve works according to the following principle. When the compressor is turned on, the air, passing through the suction valve of the cylinder, enters the compression chamber, after which it exits through the exhaust valve and enters the return inlet fitting (7). When a certain pressure is reached, the valve (6) together with the rubber ring rises and compresses the spring (4). As a result, an air passage is opened. The air moves into the housing cavity (3) and then into the outlet fitting connected to the receiver. After turning off the unit, the valve (6) returns to its place under the influence of a spring and air pressure from the receiver and closes the inlet.
Part Selection Tips
When choosing a check valve for a compressor, you should know the size of the thread cut at the outlet of the cylinder. The thread may differ in different models of units. The easiest way is to take the defective part with you and choose a similar one in the store.
If you want to change the return, for example, to a more reliable model, you should familiarize yourself with the technical characteristics of the new part. Some of them are not designed to work with high pressure compressors. Usually on the packaging to the return it is indicated maximum pressurewhere he can work.
The temperature characteristics of this node should also be taken into account. If the air after compression is heated to high temperatures, then you should not buy a plastic knot. Preference should be given to a metal non-return valve that is installed inside the duct.
Advice! A good option is a collapsible brass return. If it fails, you can always find spare parts for repair.
How to make a check valve with your own hands
There are situations when the air compressor return line is out of order, and for some reason it is not possible to buy a new part. In this case, the part can be made by hand.
On the Internet, you can find quite complex methods for manufacturing this assembly using turning and milling machines and other equipment. But still there is a way to make a simple homemade valve from improvised means. A drawing of this node is shown below.
To make a return, you will need a metal pipe or tee, a spring, a coupling, a metal threaded plug and a ball.
Advice! Ideally, a ball from an old computer mouse will do. It has a rubber coating that will provide a tighter seal to the inlet.
The air check valve is made as follows.
- Take a piece of metal tube of the required size and cut internal threads on both sides of it.
- Drill a hole in the side of the tube and weld an outlet (threaded). The receiver will be connected to it. You can also try to find a suitable tee. In this case, it is not necessary to weld the branch.
- Screw the coupling into one part of the tube (tee), as shown in the drawing.
- Insert the ball into the body and press it with a spring. The spring must press the ball with sufficient force and not be too loose.
- Pressing the spring, tighten the metal plug. At this stage, the production of the return is completed.
Advice! To prevent the ball from flying out through the side outlet during compressor operation, you can also cut a thread in it and screw in a stopper with a hole.
After this unit is ready, its inlet pipe is connected to the cylinder of the unit, and the second to the receiver.
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