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Motorized Valve’s Common Problem And Cause

Motorized Valve is an important part of nuclear power system. Because of the complicated environment in which the motorized valve is used, the causes of the valve itself and the external influencing factors are very easy to cause a series of problems which lead to the failure of the motorized Valve to operate normally The normal operation of nuclear power enterprises and the safety of nuclear power system are seriously affected. This paper enumerates the common problems in the operation of motorized Valve, and analyzes the causes of these problems.


1.1 Damage To The Valve Itself

motorized Valve in the operation process often appears its own damage, especially the multi-turn motorized valve and the Rotary motorized Valve.

Among them, the unscientific choice of dynamic parameters is the main factor affecting the normal operation of the motorized valve. The electric device of the valve needs to set different dynamic parameters, once the set dynamic parameters do not match with the actual operation, its operation will be a problem.

Improper selection of Torque is the main performance of improper selection of power parameters of motorized valve, too small output torque will affect the normal opening and closing of motorized valve, resulting in motorized valve motor burn. At the same time it will cause the motorized valve motor running temperature too high and damage. But once the excessive torque choice control error, will cause the valve control failure, damage the motorized valve local structure.

1.2 Improper Valve Installation

The actual position of the motorized valve and the system feedback signal error, resulting in the valve sealing deviation from the center, self-locking effect can not meet the requirements of the valve closed loosely. It is found that the first-stage motorized device, reducer and independent gear of the motorized valve are prone to unstable coincidence, which seriously affects the sealing of the valve. In the process of operation, the motorized valve requires high precision control, and its control contacts, which requires the corresponding position of the motorized valve accurate. Thereby improving the self-locking sealing performance of the valve.

1.3 Debugging Problems Of Motorized Valves

Motorized Switch is through the power valve limit switch to control. The main problem with motorized regulation is that the electric control can not be opened after the valve is manually closed, and excessive adjustment of the electric regulation stroke will cause the speed reducer and the valve to crash The motor that burned the valve shut down the whole system. The internal control medium of the motorized valve in operation constantly wears the valve, which makes the parts of the valve aging seriously and affects the sealing of the valve seriously.


2.1 Improper Choice Of Motorized Valve Parameters

The choice of output Torque is the key to the normal operation of motorized valve.

In comparison, too much torque is more harmful. The main harm of low output torque is to damage the electric motor, and the output Torque will destroy the internal structure of the valve, resulting in the valve can not work properly. The maintenance of the former is simple, the maintenance of the latter is more complex. Therefore, in the nuclear power system, the valve power parameter choice is the key. Design and installation must strictly control the scope of dynamic parameters, a reasonable choice of maximum and minimum value. The output speed of the electric device will have an effect on the opening and closing time of the motorized valve. The opening and closing of the valve need a large driving force The electric drive force of the valve will be insufficient to affect the normal operation of the electric device. It is easy to overload the electric device when the parameters are too large.

2.2 The Feedback Signal Does Not Match The Actual Valve Position

Mainly in the first-stage multi-turn electric device and two-stage reducer combination, the valve position feedback signal and the actual valve position does not match. Valve position signal is mainly reflected in the first electric device, and the second gear reducer is mainly nonlinear operation. The valve position only has the individual information and the feedback information matching, other information all has the error. Therefore, it is necessary to avoid the combination mode of the first-stage multi-turn electric device and the second-stage reducer. The normal operation of the valve opening and closing determines the sealing of the valve. Once the feedback signal can not match the actual position, it will affect the sealing of the valve and threaten the safety of the whole system.

2.3 Greater Than Standard Test Run Of Motorized Valve

Motorized Control Valve position, once its travel is larger than the standard range, will produce a strong impact damage valve. And motorized Valve limit switch position fixed, long-term operation will wear out its control medium. Valve Control Accuracy and feedback signal accuracy is the primary factor in the selection of Valves, which is related to the valve’s self-locking performance. The selection of high precision and accurate signal feedback valve can reduce the frequency of motorized valve problems, improve its operation stability.

2.4 The Valve Design Does Not Match The Finished Product

Motorized Valve design and production by different units, so to strengthen the effective communication between the various units. Avoid Valve design and actual application inconsistent, resulting in valve idle, waste of resources. In particular, the electric device, its complex structure, high production costs, production through more links, once the design and production is not reasonable, will greatly increase the cost of valve production. Because of the complex structure of the electric device, it is easy to be out of order. Therefore, the production process must be strictly controlled and the finished product must be tested before being put into use.


During the operation of motorized valve, there are many problems, such as the damage of the motorized valve, the improper position of the valve, the problem of adjusting the valve, the waste of the valve resources, the sealing performance of the valve, etc.  At the same time, it also brings a lot of trouble to the valve trouble-shooting. Therefore, in the selection and use of motorized valves, to strictly control the quality of the valve, strengthen communication between various departments, to ensure the stability of the operation of motorized valves. At the same time to ensure the quality of motorized valves, can reduce the production and maintenance costs of nuclear power enterprises, improve the economic benefits of enterprises.

COVNA, as a motorized valve manufacturer. We focus on manufacture high quality products and provider automation solution. We have various kinds of product for every applications. All our products have a one-year warranty. If the valve fails during use, please contact us immediately and we will help you to deal with the problem.

Post time: Jul-28-2021
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