A thread - ended safety valve is a safety device that is fixed to pipelines or containers through a threaded connection and is used to control the pressure in fluid systems. The following is a detailed introduction:
Working Principle
It usually consists of components such as a valve seat, a valve disc, and a spring. When the pressure in the system is lower than the set pressure of the safety valve, the force of the spring presses the valve disc against the valve seat, keeping the valve in a closed state. When the pressure in the system reaches or exceeds the set pressure, the force exerted by the medium on the valve disc overcomes the force of the spring, causing the valve disc to open and the medium to be discharged rapidly, thereby reducing the system pressure. As the system pressure decreases, the force of the spring presses the valve disc against the valve seat again, closing the valve.
Structural Features
Simple Structure: For example, a direct - spring - loaded threaded safety valve is mainly composed of basic components such as a valve body, a valve seat, a valve core, and a spring, without complex auxiliary devices.
Convenient Connection: Using a threaded connection, it is relatively convenient to install and disassemble from pipelines or equipment. It can be quickly installed and replaced, and can adapt to the requirements of different spatial layouts and installation positions.
Compact Size: The overall structure is compact, taking up little space. When installed on pipeline systems or equipment with limited space, it will not occupy excessive space resources.
Performance Advantages
High Precision and Reliability: It can accurately open and close at the set pressure value, respond quickly and accurately to changes in system pressure, and reliably protect the safety of equipment and pipelines.
Small Set Pressure Deviation: Generally, it can reach ±3%, enabling accurate setting of the pressure value and providing stable and reliable pressure protection for the system.
Small Opening and Closing Pressure Difference: It can respond quickly to pressure changes, opening for pressure relief and closing to maintain pressure in a timely manner, improving the safety of the system.
Material Selection
Valve Body Material: Commonly used materials include stainless steel 304, 316, carbon steel, and cast iron. Stainless steel is corrosion - resistant and suitable for environments with corrosive media; carbon steel has high strength and low cost and can be used in general working conditions; cast iron has good wear - resistance and compression - resistance and is suitable for some occasions where the requirement for corrosion resistance is not high.
Sealing Material: The sealing surfaces of the valve seat and the valve disc often use metal materials or soft materials. Metal seals are resistant to high temperatures and high pressures and are suitable for high - temperature and high - pressure working conditions; soft seals such as polytetrafluoroethylene have good sealing performance and can achieve a good sealing effect, being suitable for some occasions with high sealing requirements and mild media.
Application Scope
It is widely used in various industrial fields:
Oil and Gas Industry: It is used to control the pressure of pipelines and storage tanks, ensuring the safe operation of oil and gas transportation and storage processes.
Chemical and Pharmaceutical Industries: It protects the pressure stability of reaction kettles, storage tanks, etc., preventing chemical reaction runaway or equipment damage caused by abnormal pressure.
Manufacturing Industry: It can protect the pressure systems of machines and equipment, preventing malfunctions and damage caused by over - pressure and ensuring the normal operation of production equipment.
Food Processing Industry: It is used to control the pressure of food processing equipment, ensuring food safety and hygiene and avoiding the impact of pressure problems on food quality.
Aerospace Field: In the fuel systems of aircraft and rockets, it ensures pressure stability and safety, which is crucial for the safe operation of aircraft.
Common Types
Direct - Spring - Loaded Threaded Safety Valve: It has a simple structure, sensitive and rapid action, small size, light weight, and is easy to maintain. It is suitable for pressure vessels in the petroleum, chemical, and metallurgical industries with a working temperature ≤ 200°C.
Pilot - Operated Threaded Safety Valve: It has the functions of automatic opening and closing, certain adjustment accuracy, and can achieve remote automatic control or manual operation. It also has self - diagnosis and signal feedback devices. It is suitable for pressure vessels in industries such as petroleum and chemical with a working temperature ≤ 200°C and a nominal diameter of DN65 - DN300.
Imported Threaded Duplex Safety Valve: Two safety valves of the same specification are installed on one valve body, improving the reliability and safety of the system. If one safety valve fails, the other can still function. It is widely used in industries such as petroleum, chemical, electric power, and pharmaceuticals.
