A safety valve is an overpressure protection device. When the pressure inside the equipment, container, or pipeline exceeds the allowable value, the valve will automatically open and then discharge completely, preventing the pressure inside the equipment, container, or pipeline from continuing to rise; When the pressure drops to the specified value, the valve will automatically close in a timely manner to protect the safe operation of equipment, containers, or pipelines.
At present, safety valves are mainly used in boilers, pressure vessels, and pipelines, playing an important protective role in personal safety and equipment operation, and are widely used in industries such as pharmaceuticals. It is reported that since 2013, the market size of China's safety valve industry has gradually expanded, and the number of qualified enterprises producing safety valves has also increased. In addition, the market share of imported valves in the domestic market has gradually declined, and domestic valves have gradually risen. Overall, the development space for domestic safety valves in the future is very broad.
For users, choosing a safety valve produced by a legitimate manufacturer, installing it correctly, and operating it reasonably is a prerequisite for ensuring its stable operation. However, during the use of safety valves, problems such as jumping and internal leakage often occur. So, how should we identify the cause and solve it? The industry has provided three directions for reference.
Firstly, there is a leakage in the safety valve. Industry insiders say that when a small leak occurs in a safety valve, it is generally not easy to find, but even a small leak point can expand and erode in the middle. In the face of the situation, users need to inspect the safety valve.
The test method is to cover the sealing surface with water and observe whether there is foam after the pressure is tested. The industry points out that "the safety valve program stipulates that soft seals must be bubble free, and hard seals may be available, but the rate of bubble generation must be within a certain range. This should be done after calibration is completed, as the safety valve may damage the sealing surface during the calibration process
Secondly, the spring may experience fatigue. It is understood that springs are greatly affected by temperature, environment (if the safety valve is closed, the influence of the medium should also be considered), etc. If this is the reason, the selection or quality of the safety valve needs to be considered. This also requires users to consider whether the selection of safety valves is reasonable and whether the quality is up to standard when choosing safety valves.
Thirdly, pipeline factors. For example, vibration and impact can cause excessive pressure in the safety valve setting, causing the valve core to detach from the sealing surface of the valve seat, resulting in damage, slag inclusion, etc.
Industry insiders have stated that in fact, the manufacturing requirements for safety valves are quite high. Due to the sealing force of safety valves being equal to spring force - moderate pressure, which is similar to that of general places such as power plant main steam, feedwater pressure, and working pressure safety valves, the actual sealing force of the sealing surface is not too large. Under low pressure, good sealing is desired, and the sealing surface needs to be processed with high precision and material requirements.
Fourthly, the performance of the spring is unstable. The industry believes that the spring performance of safety valves must be very stable, as high medium temperatures can cause a decrease in the output of the spring, which can lead to poor sealing. Especially for steam safety valves with recoil plates, leakage may cause the safety valve to trip, thereby affecting power supply.
In addition, it is recommended not to perform self maintenance in the industry. Safety valves are important components for ensuring the safe operation of equipment, and only qualified inspection units can inspect and maintain safety valves. Suggest disassembling and assembling once a year, and submitting for inspection.
