Gas solenoid valves have the longest application history and are still in use around the world, especially for valves with a diameter of DN300mm or less, and still dominate in various types of valves. Its characteristic is that the pressure difference between the front, back, left, and right sides of the valve plate forces the valve plate to press against the high-pressure gate valve on the right side of the outlet, which has good sealing performance. When fully opened, the working pressure damage is small because the valve plate is not left on the flow channel. Used to disconnect substances in the pipeline.
Its drawback is that the actual operating torque is high, and the valve body and stem are most easily damaged during actual operation, especially for large-diameter gas solenoid valves. The size and net weight are also large. The DN1000 specification gas solenoid valve is about 3200mm high and requires four people to operate it. Therefore, gas solenoid valves are generally used in applications with diameters below DN500.
When the gas solenoid valve is fully open to the middle opening, the flow resistance of the valve is relatively small. When it is close to fully closed, the flow resistance increases significantly. Within a large range, the change in flow resistance is relatively small. When approaching full closure, the total flow rate changes greatly, so it is not necessary to apply it when the valve is close to closure. At this time, it is impossible to adjust the total flow rate.
If the valve opening is very small and the water flow at the interface is fast, it will cause cavitation on the lower side of the gate, accompanied by violent vibration and noise. Long term operation of the throttle valve usually causes cavitation in the metal materials of the valve body and gate.
If the load of the gas solenoid valve is in the middle opening, the valve plate will be closely coordinated with each other when fully closed due to the support points of the sliding rails on both sides. However, when in the middle position, the gap between the valve plate and the sliding rail will be large, causing vibration.
Therefore, even in areas with low incidence of cavitation, long-term operation of the throttle valve can cause deformation, friction coefficient, or damage to the slide rail. Moreover, because high-pressure gate valves do not touch in all directions, and the surface working pressure at the touch location is high, it usually causes biting or sticking.
Therefore, it is not suitable for traffic monitoring. It should be noted that when the gas solenoid valve is opened at a small degree, the total flow rate changes greatly. If the valve is opened or closed in an emergency, it will cause a significant increase in working pressure or air pressure, which is especially caused by water hammer when the valve is closed.
