The safe operation of pressure equipment and containers is crucial in industrial production. Once the pressure exceeds the limit, it may trigger serious safety accidents, causing huge casualties and property losses. As an efficient and reliable safety device, the duplex spring safety valve provides a solid guarantee for pressure systems. This article will delve into the design principles, advantages, and practical applications of the duplex spring safety valve, helping everyone better understand this important industrial equipment.
The duplex spring safety valve is a special type of spring-loaded safety valve, consisting of two safety valves of the same specification installed on a Y-type joint. Its nominal diameter refers to the inlet diameter of the Y-type joint. The core of this design lies in the parallel architecture of double valve discs and double springs, which is different from the traditional single-spring safety valve. It integrates two independent safety valves sharing the same inlet pipeline within one valve body and shares a common outlet channel, achieving dual pressure monitoring and higher safety.
The duplex spring safety valve mainly consists of three parts: the valve seat, the valve disc (valve core), and the loading mechanism. The valve seat is the part that connects the safety valve to the equipment, which may be integrally formed with the valve body or assembled together. The valve disc is closely fitted with the valve seat through the valve stem, serving to seal and control the flow of the medium. The loading mechanism uses the elastic force of the spring to achieve the clamping and opening control of the valve disc.
During normal operation, the double springs clamp the valve disc tightly against the valve seat through pre-tensioning force to form a seal. When the medium pressure rises to 90% of the set value, the springs begin to compress slightly, and the valve disc is in a critical open state. When the pressure exceeds the set pressure (e.g., 0.8 MPa), the double springs compress synchronously, the valve disc quickly moves upward, and the medium is discharged through the gap between the valve seat and the valve disc. As the medium is discharged, the system pressure drops to 70% - 80% of the set pressure, the spring reset force exceeds the medium thrust, and the valve disc falls back to close.
The duplex spring safety valve is a special safety valve, and its design principles and working methods are crucial for ensuring the safe operation of pressure systems. The structural design of the safety valve, its working principle, and the coordinated operation of its components ensure that pressure can be released in a timely and effective manner when it exceeds the limit, preventing equipment damage and safety accidents. Next, let's take a look at the many advantages of the duplex spring safety valve.
The biggest advantage of the duplex spring safety valve lies in its dual safety assurance mechanism. Each valve disc is equipped with an independent spring, and the spring force is precisely set through the adjusting screw to achieve dual pressure monitoring. Even if one valve disc fails due to spring fatigue, seal face wear, or other reasons, the other valve disc can still work independently, avoiding safety failure caused by a single failure. This design greatly improves the reliability of the system and ensures effective prevention of equipment overpressure under any circumstances.
The parallel arrangement of the two valves doubles the effective discharge area, making it suitable for scenarios that require high-capacity pressure relief. For example, a duplex spring safety valve with a DN100 diameter can have a discharge capacity twice that of a single valve. When the pressure exceeds the set value, the two valve discs can quickly open synchronously, rapidly discharging the medium and reducing system pressure. The linkage mechanism ensures that the two valve discs open to the same height, avoiding uneven opening that could cause uneven loading and wear, further improving the pressure relief efficiency and the service life of the equipment.
The valve disc and valve seat use metal hard sealing (such as hard alloy welding) or flexible sealing (such as PTFE), with a leakage rate of less than 0.01% of the rated discharge capacity. The introduction of a flexible valve disc structure greatly improves the valve's anti-vibration capability and significantly enhances sealing stability. In actual operation, even if there is a certain degree of vibration, the flexible valve disc valve is not prone to leakage. This structure not only improves the operating sealing performance but also increases the operating pressure value that maintains sealing, effectively delaying the valve's pre-leakage point.
The duplex spring safety valve can easily adjust the opening pressure of the safety valve by changing the tightness of the spring through the adjusting screw on the upper part of the valve stem. This adjustment method is simple and quick, meeting the pressure control requirements under different working conditions. At the same time, it is small in size and light in weight, with a large exhaust capacity, suitable for boilers of different parameters and capacities, and has a wide range of applications.
The duplex spring safety valve is widely used in pressure systems such as pressure vessels, boilers, and pressure pipelines, providing reliable safety assurance for industrial production. In these application scenarios, the duplex spring safety valve can effectively prevent equipment overpressure and ensure the normal operation of the system.
In boiler systems, the duplex spring safety valve is an essential safety device. During operation, the internal pressure of the boiler continuously increases with the generation of steam. When the pressure exceeds the set safety value, the duplex spring safety valve can quickly open to discharge excess steam, reducing the pressure inside the boiler and preventing safety accidents such as boiler explosion due to overpressure. At the same time, its efficient pressure relief capability and excellent sealing performance ensure the stable operation of the boiler system and improve production efficiency.
Pressure vessels are widely used in industries such as chemical, pharmaceutical, and food. These containers need to strictly control the internal pressure when storing and transporting high-pressure gases or liquids. The duplex spring safety valve can monitor the pressure changes inside the pressure vessel in real time, and open in time to relieve pressure when the pressure exceeds the set value, protecting the pressure vessel from damage. Its dual safety assurance mechanism and efficient pressure relief capability provide strong security for the safe operation of the pressure vessel.
In industrial production, pressure pipelines are used to transport various high-pressure media. The duplex spring safety valve installed on the pressure pipeline can effectively prevent the pipeline from bursting or exploding due to overpressure. When the pressure inside the pipeline exceeds the set value, the safety valve quickly opens to discharge excess media and reduce the pressure inside the pipeline. At the same time, its excellent sealing performance and anti-vibration capability ensure the safe operation of the pressure pipeline under complex working conditions.
To ensure the normal operation and service life of the duplex spring safety valve, regular maintenance and care are essential. Here are some common maintenance and care measures.
Regularly inspect the duplex spring safety valve, including visual inspection, sealing performance inspection, and spring elasticity inspection. Check for corrosion, cracks, and other phenomena on the valve body surface, and check for wear and deformation on the sealing surfaces of the valve disc and valve seat. At the same time, check whether the spring elasticity is normal and whether there are any fatigue or breakage phenomena. Timely repair or replacement of any problems found to ensure the normal operation of the safety valve.
Regularly clean and lubricate the duplex spring safety valve. Remove dust, oil, and other impurities from the valve body surface to prevent impurities from entering the valve and affecting sealing performance and action sensitivity. At the same time, lubricate components such as the valve stem and screw rod to maintain their good operating condition, reduce wear, and extend service life.
Regularly calibrate and adjust the duplex spring safety valve to ensure that its opening and closing pressures meet the set requirements. During calibration, professional calibration equipment should be used and operations should be carried out in accordance with the prescribed procedures. During adjustment, adjust the tightness of the spring according to the actual working conditions to achieve the best state for the opening and closing pressures of the safety valve. After calibration and adjustment, records should be kept for future reference.
As an efficient and reliable safety device, the duplex spring safety valve plays a vital role in the safe operation of pressure systems. Its unique double valve disc + double spring parallel architecture achieves dual pressure monitoring and efficient pressure relief capability, providing a solid safety guarantee for industrial production. At the same time, its excellent sealing performance and convenient adjustment features make it perform well in various application scenarios. In actual use, we should pay attention to the maintenance and care of the duplex spring safety valve to ensure that it is always in good working condition and safeguard the safe and stable operation of industrial production.
