Working principle of cylinder throttle valve, characteristics and selection of cylinder throttle valve

How the cylinder throttle valve works


The valve stem clamps the flexible rubber tube to produce a throttling effect. Gas pressure can also be used to compress the rubber tube instead of the valve stem. The flexible throttle valve has a simple structure, small pressure drop and high action reliability. It is not sensitive to pollution, and the usual working pressure range is 0.3-0.63MPa.
It is more difficult to use a pneumatic flow control valve to adjust the speed of a pneumatic actuator than a hydraulic flow control valve because the gas is compressible. Therefore, when using a pneumatic flow control valve to adjust speed, attention should be paid to the following points to prevent crawling:
(1) There should be no air leakage on the pipeline;
(2) The lubrication condition between the cylinder and piston should be good;
(3) The flow control valve should be installed around the cylinder or air motor as much as possible;
(4) Use outlet throttling and speed regulation as much as possible;
(5) The external load should be stable. If the external load changes significantly, hydraulic or mechanical devices (such as gas-hydraulic linkage) should be used to compensate for the speed changes caused by load changes.


The working principle of the cylinder one-way throttle valve is a combined flow control valve composed of a one-way valve and a throttle valve connected in parallel. As shown in the figure below, when the airflow flows along one direction, such as P to A, it passes through The throttle valve throttles;when the airflow flows in the opposite direction from A to P, the one-way valve opens without throttling. One-way throttle valves are often used in cylinder speed regulation and delay circuits.








The working principle of the cylinder exhaust throttle valve is a control valve installed at the exhaust port of an actuator (such as a pneumatic motor) to regulate the flow of gas entering the atmosphere. It can not only adjust the movement speed of the actuator, but also often has muffler devices, so it can also reduce the effect of exhaust noise.
The figure below shows the working principle of the exhaust throttle valve. Its working principle is similar to that of a throttle valve. The exhaust flow is adjusted by adjusting the flow area of ​​the throttle port 1, and the exhaust noise is reduced by the muffler sleeve 2.








Characteristics and selection of cylinder throttle valve


The cylinder throttle is an essential accessory of the cylinder. Most people rarely pay attention to this standard part. When selecting, they only care about choosing ø4 or ø6, or if the bore is too large, choose ø8. Is there anything else I should pay attention to?





The throttle valve is divided into intake throttling and exhaust throttling. As the name implies: one throttles when the air is in and the other throttle when the air is out. If the airflow is from the threaded end to the air pipe end, and the adjustment nut has obvious effect after adjustment, it is an exhaust throttle valve. On the contrary, it is the intake throttle valve (many people go to the site and do not know how to adjust the cylinder speed).





When the air is throttled, the exhaust chamber pressure is small (connected to atmospheric pressure), and the air inlet chamber is filled with restricted gas. The air flow is small, and the initial pressure is small. When the cylinder load is large, there will be crawling and then rushing. When the air is throttled, the pressure in the exhaust chamber will not suddenly drop to zero due to the action of the limited flow valve. The pressure in the air inlet chamber is the same as that of the air source, which can form a more stable pressure difference and achieve better speed regulation effects. When common single-acting cylinders or air blowers use exhaust throttling, the throttle valve will not work at all (this is very common, not to mention assembly, but not engineering), because the flow is limited by the return stroke of the cylinder. The return stroke of the cylinder is generally unloaded.





Pressure regulating cap locking function
You may be familiar with this. As shown in the picture at the beginning, some brands have a pressure regulating cap locking function. After the cylinder speed is adjusted, in some places with high speed requirements, in order to prevent the vibration from changing over time or other personnel accidentally touching it, this type of speed regulating valve is of course more expensive. In general, ordinary ones can be used.

Selection of throttle valve diameter
The thread specification of the throttle valve is selected according to the cylinder, and the speed control valve connection diameter is selected according to the corresponding cylinder bore. Generally, the recommended diameter is listed at the beginning of the brand manual, you can refer to the selection. Avoid choosing a trachea diameter that is too small, which may cause the cylinder to fail to move or crawl.



The above is the working principle of the cylinder throttle valve, the characteristics and selection content of the cylinder throttle valve. If you want to know more relevant information, please log in to Sunway Pneumatic www.diancifa.cc.