Detailed explanation of gas safety valve:
The lever safety valve mainly relies on the force of the lever weight to work, but the large size of the lever safety valve often limits the selection range. When the temperature is high, a safety valve with a radiator is selected. The main parameter of the gas safety valve is the displacement, which depends on the diameter of the valve seat and the opening height of the valve disc. According to the difference in opening height, it can be divided into two types: micro-opening type and full-opening type. The micro-opening type means that the opening height of the disc is 1/40-1/20 of the throat diameter of the valve seat. The full opening type means that the opening height of the disc is 1/4 of the throat diameter of the valve seat.
Working principle of gas safety valve:
The safety valve plays a role of safety protection in the system. When the system pressure exceeds the specified value, the safety valve opens to discharge part of the gas in the system into the atmosphere, so that the system pressure does not exceed the allowable value, so as to ensure that the system will not cause accidents due to excessive pressure. Safety valve is also called relief valve.
1. Piston safety valve
The spool is a flat plate. The air source pressure acts on the piston A. When the pressure exceeds the safety value determined by the spring force, the piston A is pushed open, and a part of the compressed air is discharged into the atmosphere from the valve port; when the air source pressure is lower than the safety value, the spring drives The piston moves down, closing the valve port.
2. Ball valve type and diaphragm type safety valve
The working principle is exactly the same as the piston type. These three kinds of safety valves all use springs to provide control force, and the safety value can be changed by adjusting the spring preload, so they are called direct-acting safety valves.
3. Pilot-operated safety valve
A small direct-acting valve provides control pressure to act on the diaphragm, and the hard core on the diaphragm is the valve core, which is pressed on the valve seat. When the air source pressure A is greater than the safety pressure, the valve core opens, and the compressed air is discharged into the atmosphere from the left output hole. Diaphragm safety valves and pilot safety valves have better pressure characteristics and sensitive action; but the maximum opening force is relatively small, that is, the flow characteristics are poor. In actual application, the type of safety valve should be selected according to actual needs, and its diameter should be selected according to the larger displacement.