Structure and Fault Analysis of Spring-loaded Safety Valve
A spring-loaded safety valve relies on the elastic pressure of a spring to seal the valve's disc or piston. Once the pressure in the pressure vessel exceeds the spring pressure, the locking device is pushed open, creating a pressure relief channel to release the high pressure. There are two types based on the opening height of the valve disc: full lift and micro lift. The full lift type has a larger release capacity and better rebound force, suitable for both liquid and gas media, while the micro lift type is only suitable for liquid media.
Working Principle:
Analysis of the opening characteristics of the spring-loaded safety valve reveals that as an external force (FW) acts on it, the valve goes through the entire process from closing to opening and then back to closing. The change in the external force FW during this process is crucial. When the additional force gradually increases, reaching the sum of the internal pressure (PL × S) equal to the spring preload force, the valve slightly opens. This increases the effective area (S), causing a sharp increase in the internal pressure acting force needed to overcome the spring preload force. This results in the momentary decrease of the external force, creating the first characteristic peak (A). As the external force gradually decreases to reach the closing point, the effective area suddenly decreases, causing a momentary rebound of the external force, forming the second characteristic peak (B). These two characteristic peaks A and B serve as the technical basis for testing the opening pressure and reseating pressure of the safety valve under operating conditions.
Fault Analysis:
1. Leakage: Excessive leakage between the valve disc and the seat due to dirt or damage, which can be resolved by cleaning, grinding, or replacing parts.
2. Valve disc flutter or vibration: Usually caused by excessive spring stiffness or improper adjustment of the adjusting ring, which can be corrected by adjusting the spring stiffness or ring position.
3. Failure to open at specified pressure: Could be due to inaccurate pressure setting or mechanical issues like sticking valve components, which may require readjustment or replacement.
4. Failure to reseat after discharge: Could be caused by bent or misaligned valve components, requiring reassembly.
5. Pressure continues to rise after discharge: Possible causes include undersized valve capacity or mechanical issues like rusted parts, requiring replacement or repair.
Installation Points:
1. Test the sealing performance before installation and replace any damaged components.
2. Install the safety valve vertically with precise angles and assistive tools.
3. Avoid applying pressure at the outlet during installation.
4. Wear gloves to prevent oil contamination, and test the valve before use with at least two operators present.
5. If your spring-loaded safety valve experiences faults, prompt repair is advised to ensure proper functionality.
Working Principle:
Analysis of the opening characteristics of the spring-loaded safety valve reveals that as an external force (FW) acts on it, the valve goes through the entire process from closing to opening and then back to closing. The change in the external force FW during this process is crucial. When the additional force gradually increases, reaching the sum of the internal pressure (PL × S) equal to the spring preload force, the valve slightly opens. This increases the effective area (S), causing a sharp increase in the internal pressure acting force needed to overcome the spring preload force. This results in the momentary decrease of the external force, creating the first characteristic peak (A). As the external force gradually decreases to reach the closing point, the effective area suddenly decreases, causing a momentary rebound of the external force, forming the second characteristic peak (B). These two characteristic peaks A and B serve as the technical basis for testing the opening pressure and reseating pressure of the safety valve under operating conditions.
Fault Analysis:
1. Leakage: Excessive leakage between the valve disc and the seat due to dirt or damage, which can be resolved by cleaning, grinding, or replacing parts.
2. Valve disc flutter or vibration: Usually caused by excessive spring stiffness or improper adjustment of the adjusting ring, which can be corrected by adjusting the spring stiffness or ring position.
3. Failure to open at specified pressure: Could be due to inaccurate pressure setting or mechanical issues like sticking valve components, which may require readjustment or replacement.
4. Failure to reseat after discharge: Could be caused by bent or misaligned valve components, requiring reassembly.
5. Pressure continues to rise after discharge: Possible causes include undersized valve capacity or mechanical issues like rusted parts, requiring replacement or repair.
Installation Points:
1. Test the sealing performance before installation and replace any damaged components.
2. Install the safety valve vertically with precise angles and assistive tools.
3. Avoid applying pressure at the outlet during installation.
4. Wear gloves to prevent oil contamination, and test the valve before use with at least two operators present.
5. If your spring-loaded safety valve experiences faults, prompt repair is advised to ensure proper functionality.