Electric eccentric hemispherical valve is widely used in industrial production. Due to its unique structure, good adjustment performance and rapid opening and closing, it has become a key equipment in fluid control systems. However, some common faults may occur in the electric eccentric hemispherical valve during long-term use. These faults not only affect its normal operation, but may also cause damage to the equipment or even failure of the entire system. Therefore, understanding the causes of these faults and the corresponding preventive measures is of great significance for extending the service life of the valve and ensuring the stable operation of production

1. Internal leakage
Internal leakage is one of the most common faults in electric eccentric hemispherical valves, especially in the case of frequent opening and closing. It is mainly manifested as leakage on the valve sealing surface, causing medium loss. The occurrence of internal leakage is often related to the following factors:

01. Damage to the sealing surface coating
The sealing surface of the valve is easily eroded or corroded during long-term use, causing the coating to gradually fall off and the sealing performance to decrease.

02. Improper selection of sealing pair
If the material or design of the sealing pair is not suitable, it may cause the sealing surface to stick during the opening and closing process, which in turn causes the sealing surface to be strained or worn.

03. Solid particle scouring of the medium
Under certain working conditions, the medium contains a large amount of solid particles or impurities, which will cause strong scouring of the sealing surface when the valve is opened. As the use time increases, the sealing pair gradually fails, and eventually causes internal leakage.

For the internal leakage problem, we should choose suitable sealing materials and regularly check the condition of the sealing surface, especially in working conditions with more complex media, pay special attention to the cleanliness of the medium to avoid damage to the sealing surface by solid particles.

2. Stuck and inadequate switch
The jamming failure is manifested as the valve is not flexible when opening or closing, or even unable to open and close normally. The causes of jamming are relatively complex, and common causes include:

01. Sealing surface damage
During the use of the valve, the sealing surface may be damaged due to excessive friction or scouring of particles, making it difficult to open or close the valve.

02. Solid particle blockage
Under certain working conditions, the medium may contain a large amount of solid particles, which accumulate in the valve cavity, hindering the normal movement of the valve and causing jamming.

03. Structural design problems
If the bearing or sleeve of the valve is not hardened, or the design structure is unreasonable, it will cause excessive friction, increase the difficulty of opening, and even cause the valve to jam under high temperature and high pressure.
In addition, due to the large opening pressure difference and high temperature in some sections, the friction of the valve sealing surface will also increase. At this time, if the valve opening frequency is too high, the heat generated by the friction of the sealing surface will cause the temperature to rise, accelerate the wear of the sealing surface, and then cause jamming.

3. Three Inaccurate zero position setting of the actuator
The actuator of the electric eccentric hemispherical valve is responsible for controlling the opening and closing of the valve, but if the zero position setting of the actuator is inaccurate, it may cause the valve to not be completely closed, resulting in internal leakage. Inaccurate zero position setting is usually caused by the following reasons:

Improper actuator calibration: If the actuator is not accurately calibrated during installation, or the calibration process is not precise, it may cause the actuator to fail to reach the expected closed position when controlling the valve, resulting in internal leakage.

Problems with the actuator itself: Sometimes, the zero position sensor or electronic control system of the actuator may fail, resulting in zero position error, so that the valve cannot be completely closed.

For this situation, the user should regularly check the working status of the actuator to ensure that its zero position setting is accurate to avoid internal leakage of the valve.

4. Actuator failure
The actuator of the electric eccentric hemispherical valve is one of its key components, responsible for converting electrical signals into mechanical actions to control the opening and closing of the valve. Actuator failure may cause the valve to fail to open or close normally, or even fail to accurately adjust the opening of the valve. The main reasons for actuator failure are as follows:

01. Power failure
The actuator requires a stable power supply to work properly. Once the power supply fails, it may cause the actuator to lose control, thereby affecting the operation of the valve.

02. Motor overload
Long-term overload operation of the actuator motor will cause damage to the motor and affect the normal operation of the valve.

03. Position sensor failure
The position signal sensor of the actuator fails, which will cause the valve to fail to accurately adjust the opening or fail to accurately stop at the specified position.

04. Control signal problem
If the control signal of the actuator is disturbed or fails, the valve will also fail to operate according to the predetermined switching state.

Therefore, regular inspection of various parts of the actuator, especially the power supply, sensor and control signal system, is the key to ensure reliable operation of the valve.

5. Valve blockage
Valve blockage is mainly caused by the accumulation of impurities or solid particles in the medium inside the valve, which makes the valve unable to open and close normally. Especially when dealing with media containing impurities or solid particles, the valve blockage phenomenon is more serious. Blockage will not only affect the normal operation of the valve, but also may cause equipment damage or system failure.

To avoid the occurrence of blockage problems, users should pay attention to the following points:

01. Clean the valve
Regularly clean the valve, especially the impurities in the valve cavity, and keep the inside and outside of the valve clean.

02. Choose a suitable filter device
In the case of a large amount of impurities in the medium, it is recommended to install a suitable filter device in front of the valve to reduce the impact of solid particles on the valve.

6. Flange leakage
Leakage at the flange connection is usually caused by uneven tightening of bolts, aging of gaskets or improper selection. Leakage at the flange connection will not only cause the medium to leak, but also may cause system pressure drop, equipment damage, and even cause safety accidents.

The key to solving this problem is:

Bolts are tightened evenly: When installing the valve, ensure that the bolts at the flange connection are tightened evenly to avoid leakage due to improper tightening.

Replace the appropriate gasket: The selection of gaskets should be determined according to the characteristics of the medium and factors such as working temperature and pressure. Check the status of the gaskets regularly and replace aging or damaged gaskets in time.

7. Worm gear transmission jamming
For large-caliber electric eccentric hemispherical valves, the worm gear transmission mechanism is an important part of its drive system. If the worm gear transmission is affected by dirt or wear, it may cause jamming, causing the valve to move slowly or fail to open and close normally. Common reasons are:

01. Dirt embedding
If the valve is used in a dirty environment, dirt enters the worm gear transmission mechanism, which may affect the lubrication effect and cause jamming.

02. Improper operation
During use, improper operation may cause damage or jamming of the transmission parts.

Therefore, in the use of large-caliber electric eccentric hemispherical valves, it is very important to keep the transmission mechanism clean and well lubricated. Regular inspection and cleaning of the worm gear transmission system is an effective way to extend its service life.