What is the three-break protection function of the pneumatic actuator?

The thrust and stroke of the pneumatic actuator are large, easy to install and fix, and have the following characteristics: easy to achieve positive/reaction setting, long stroke, bypass valve can be manually operated in the short term, positioner is not subject to air source pressure changes, shockproof, fast response, three-break protection function. So, what is the three-break protection function of the pneumatic actuator?

1, gas self-locking protection

It is mainly realized by exhaust valve and locking valve. Adjust the operating pressure of the exhaust valve to a certain value, and when the air pressure is higher than the value, the normal output air pressure. Open the lock valve, so that the slide valve to both ends of the cylinder gas path connected, so that it is in the normal working state. If the air pressure is lower than the set value, the exhaust valve is blocked, and then it is switched to the air path, and the air pressure is drained through the exhaust valve. At this time, the blocking valve will block the air path, and the pneumatic actuator will maintain the original position to achieve self-locking protection.

2, off power protection

This is done through a solenoid valve. If the power supply voltage is normal, it works normally, if the power supply disappears, the solenoid valve switches the gas path, the exhaust valve will empty the air pressure, and then switch the gas path. The exhaust lock valve will make the lock valve in a locked state, maintain the load in the original position, to achieve power off protection.

3, break signal protection

This is done by an electronic switch. When the signal current is greater than the lower limit current, it works normally. When the signal current is suddenly interrupted, the electronic switch is blocked, and the electromagnetic valve is lost to realize the protection of the broken signal.