The difference between single electric control and double electric control solenoid valve

1. 2-bit 3-on only single electric control

a. For air source, only fo and FC are in two states, and there is no FL state, which is used for single action (spring reset) cylinder

b. For power supply, it is also on or off when power is off, without hovering (FL)

2. 2-position 5-way single and double electric control, used for double acting cylinder.

a. Single electric control

(a) For the gas source, FL is lost when the air source is lost, and there is no FC or fo.

(b) For power supply, FC and fo are divided when power is off

b. Double electric control

(a) For the air source, FL is lost when the air source is lost, without the theory of FC and fo

(b) For power supply, FL is lost when power is lost, no FC, fo

3. The 3 position 5-way must be double electric control, and the solenoid valve has 3 positions

(a) For the air source, FL is lost when the air source is lost, without the theory of FC and fo

(b) For power supply, when power is lost, it is the middle position, left position is required on the left and right power is powered on right

1、 The power is maintained by double electric control only, for the following reasons:

(1) The solenoid valve with single electric control and single electric control is spring. When the valve is lost, the spring will make the valve core of solenoid valve return to its original state. If there is air source, it will be strong and strong, and the cylinder will be set in a certain position.

(2) When the two / fifth way, double electric control and both sides are powered off, the valve core is set at the final position and will not move again

2、 When the air pressure is low, the material will push the butterfly valve open. This situation is usually only seen in butterfly valve, but ball valve will not. Because the area of butterfly valve is large, when the opening is small, if the support of cylinder is lost, the material will push the butterfly valve open.

Solution: load the lock valve (holding valve) before the solenoid valve

Pneumatic retaining valve (lock valve, air lock valve) is one of the auxiliary units of pneumatic unit combination instrument. When the instrument air source system fails, the holding valve can automatically cut off the channel between the regulator and the valve, so that the valve position is in the original position, so as to ensure the normal process until the air source accident is eliminated. After the normal gas supply, the holding valve will automatically open the channel between the regulator and the valve, and resume normal operation. Therefore, pneumatic valve is suitable for important automatic control circuit as a safety protection device.