Check valve for compressor

To ensure the correct operation of the compressor equipment, various technical devices are used, among which there is a check valve for the compressor. Without this node it is almost impossible to imagine the operation of equipment designed to compress air.

Purpose of the check valve

The check valve is designed to pass compressed air in one direction only. This part is installed between the cylinder of the piston compressor and the receiver, and does not allow air to return from the accumulation tank back to the compression chamber after the unit is stopped.

Important! In addition, obratnik, keeping the air in the receiver, allows you to make a smooth start equipment.If this part is removed, the air will press on the piston, and the engine will not be able to rotate the crankshaft at start-up.

In addition to the reverse, the compressor must always be installed. safety valve. This bypass valve is intended for emergency pressure relief, if the pressure switch does not shut off the engine of the unit. The following photo shows the unloading valve, without which, for safety reasons, you cannot turn on the compressor.

Device and principle of operation

The design of the reciprocal includes the following elements (see fig. Below):

• metal housing (3);

• valve (6), which closes the inlet and is equipped with guide ribs to prevent distortion;
• a rubber ring (5) installed in the upper part of the valve (6);
• a spring (4) that presses the rubber ring to the inlet and is put on the protrusions located on the plug (1) and on the valve (6);
• a cork that has a seal in the form of a cardboard gasket (2) and allows you to disassemble the assembly for cleaning and repair.

The return device, 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 on the following principle. When the compressor is turned on, the air passes through the cylinder's suction valve, enters the compression chamber, and then exits through the exhaust valve and enters the inlet fitting of the return valve (7). When a certain pressure is reached, the valve (6) together with the rubber ring rises and compresses the spring (4). As a result, the air passage opens. The air moves into the cavity of the housing (3) and then into the outlet fitting connected to the receiver. After the unit is turned off, the valve (6) under the influence of the spring and the air pressure from the receiver returns to its position and closes the inlet.

Types of check valves

There are 3 types of return pipes for air.

1. Aluminum (internal) check valve. This part of the compressor is considered the most durable, because it can withstand the temperature of the air flow up to 200 ° C. The only drawback of this detail is the relatively high price, about 600 rubles.
   

   The part is installed inside the duct, going from the cylinder to the receiver, using a coupling.

   

   

2. Plastic Reverse. Non-return valves made of plastic can be seen, for example, in the C-412 and K-24 units of the Bezhetsk plant.
   

   As can be seen from the photo above, the design of the site is very simple.Accordingly, it is possible to buy it, at a price of about 100 rubles. But this valve cannot operate at high temperatures, because the material from which it is made begins to melt.

3. Brass finder. It is used on most models of compressors from different manufacturers and costs about 250 rubles. Although this node is made mainly of metal, it fails if the air temperature during compression exceeds 140 ° C.
   

Part Tips

Choosing a check valve for the compressor, you should know the size of the thread, cut at the outlet of the cylinder. Threads may vary in different aggregate models. The easiest way is to take the defective part with you and choose the same in the store.

If you want to change the inverse, for example, to a more reliable model, you should be familiar with the technical characteristics of the new part. Some of them are not designed to work with high pressure compressors. Usually on the package to the return box indicated maximum pressureat which he can work.

You should also consider the temperature characteristics of this site. If the air after compression is heated to high temperatures, you should not buy a plastic knot.Preference should be given to a metal check valve that is installed inside the duct.

How to make a check valve do it yourself

There are situations when the air compressor obratnik has failed, and there is no possibility to buy a new part for any reason. In this case, the part can be made by hand.

On the Internet, you can find quite complex methods of manufacturing this unit 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.

For the manufacture of the reciprocator, you will need a metal pipe or a tee, a spring, a coupling, a metal cork with a thread and a ball.

Air check valve is manufactured as follows.

1. Take a piece of metal tube of the required size and cut on both sides of the internal thread.
2. Drill a hole in the side of the tube and weld a branch (with thread). The receiver will be connected to it. You can also try to find a suitable tee. In this case, there will be no need to weld the tap.
3. Screw the coupling into one part of the tube (tee), as shown in the drawing.
4. Insert the ball into the body and press it with a spring. The spring should press the ball with sufficient force and not be too relaxed.
5. Having pressed a spring, twist a metal stopper. At this stage, the manufacture of the reverse ends.

After this node is ready, its inlet branch pipe is connected to the cylinder of the unit, and the second - to the receiver.