Emergency shut-off valve is a new product developed in recent years. There are more and more applications in the application field. In addition, during the installation and commissioning process, we also found some problems, some of which were construction problems, and some were design problems.
A good product must not only have the good quality of the product itself, but more importantly, let people understand it, be familiar with it, use it reasonably, and make it play the best role.
The emergency shut-off valve is a type of hydraulic control valve. It mainly includes main valve, throttle valve, pilot valve, pressure gauge and other connecting parts. When the inlet pressure of the main valve of the wastewater solenoid valve is lower than the set pressure of the main valve, the main valve is open at this time, the pressure in the upper cover cavity of the main valve is equal to the outlet pressure of the main valve, and there is pressure in the inlet and outlet of the main valve. Poor, the water flows out from the outlet through the valve port.
When the fire pump starts, or the pressure of the variable frequency pump rises and exceeds the set pressure of the pilot valve, the drain solenoid valve is controlled by the main valve inlet to the pilot valve to control the pipeline pressure to rise, the pressure on the spring increases, and it is pressed downward to drive the valve. The core moves down to close the pilot valve. At this time, the inlet pressure of the main valve is continuously replenished into the upper cavity of the main valve cover through the throttle valve. Since the downward pressure of the disc is greater than the upward thrust, the main valve is closed.
The main point to note is that the valve whose inlet pressure is less than the set pressure is always in the open state, and the valve whose inlet pressure is greater than the set pressure is always in the closed state. Nowadays, many designers mistakenly believe that as long as the emergency shut-off valve is installed, it can be closed without any conditions. This is wrong.