11 Common Valve Faults and Treatments

The cause of the valve failure is that the valve itself has quality problems, and the second is that the user installs it incorrectly or the fluid does not meet the requirements.

In the production of valves, rigorous technology, perfect equipment, strict factory inspection and the quality of accessories outside the factory are the key factors to determine the quality of the valve itself. even.

In the need to use the correctness of the design and selection of the valve, the unit of the actual operating conditions and the scope of the valve, as well as an operation correct and serious processing, timely maintenance and direct relationship To avoid valve failure and prolong service life.

The following sorts common common faults in different valve types, build quality reasons, user reasons, and specific solutions.es for maintenance.

1. Gasket leak due to valve failure

Build quality reasons: Crate assembly does not meet requirements; the static sealing surface is rough and uneven; the sealing pair is not clean and foreign matter is added.

User\'s reasons: the seal is not selected correctly, which does not meet the requirements of temperature, pressure and corrosion resistance; the operation is not stable and the temperature fluctuation is too large.

Solution: According to the requirements of the working conditions, the material and type of seal should be selected correctly; it should be handled with care.

2. Defective valve sealing ring gasket leak

Manufacturing quality reasons: usually belong to manufacturing quality issues.

3. The Iron PieceDefective valve measurement drops (dangerous leakage due to valve failure)

The reason for the quality of workmanship: The connection between the closing part and the valve stem is not firm.

User Reasons: After the closing part exceeds top dead center or is stuck, it will break if it continues to run; the connecting piece material is not selected correctly.

Solution: Correct operation, after the valve is fully opened, the handwheel must be slightly loosened to leave a gap; the selection must take into account the average resistance to corrosion and wear.

4. Foreign body embedded between the sealing surface of the valve defect

User\'s reasons: The valve closed for a long time has accumulated dirt on the sealing surface of the valve. sealing; the backing is not clean and bonded to the sealing surface; The valve is not selected correctly andthe fluid and its deposit are not taken into account exhaustively.

Solution: Open the valve to allow the high-velocity liquid to wash away the dirt on the sealing surface; for dirty media, a filter and a sewage disposal device should be installed in front of the valve, and the valve cover should be opened for large foreign matter to come out; the medium contains hard particles, so it is not appropriate to use gate valves, but ball valves, ball valves, etc. can be used.

5. Stuck valve stem due to valve failure

Reasons for build quality: low machining accuracy of valve stem and its corresponding parts; Tighten, lock the valve stem; the valve stem nut is loose, the thread slips; the connection of the affected device is loose or damaged.

Reasons for utilizer: the trapezoidal thread is too dirty and the lubrication is extremely poor; it rusts if not used for a long time; the closing force is too great, causing deformation and damage to relevant parts;

Solution: Threading area should be cleaned, lubricated, and the sliding surface should be well lubricated; the valve stem should be checked and moved regularly; the valve must be operated correctly and the closing force must be appropriate; after the valve is properly closed, if the valve is still heated and expanded, regular relief operation should be specified Procedures, in case of upper death.

6. Damage to the handle and handwheel in case of valve failure

User\'s reasons: incorrect use of the handle and damage to the handwheel; loose fasteners; handles, keys, The connection between the handwheel and the valve stem is damaged andt the torque cannot be transmitted.

Solution: It is forbidden to use a pipe wrench, a long lever and an impact tool to operate; it must be repaired at any time; it must be repaired at all times to avoid damage.

7. Drive blockage of gears (including worm gears and worm gears) valve defects

Build quality reasons: incorrect assembly , out-of-specification deviations; Shaft sleeve clearance at bearing part is too small, lubrication is poor; the shaft is bent and the fasteners and connecting parts are loose or damaged.

User\'s reasons: the gear is not clean, embedded in dirt, affecting lubrication; malfunction.

Solution: Gears should be kept clean, refueled regularly and a dust cover should be added in a dusty environmentthem ; if the operation is found to be blocked and the resistance is large, the operation cannot be continued, otherwise the damage will be aggravated.

8. Inflexible action of pneumatic or hydraulic devices due to valve failure

Reasons for build quality: the quality of the cylinder block and valve castings cylinder head is not qualified, which leads to leaks and affects the pressure; Piston rod bent or out of tolerance range; seal and gasket leakage, which affects pressure; the quality of the parts is poor or the assembly is not correct; the return spring in the cylinder is loose; the signal indication system is faulty; the packaging is too tight.

User Reasons: Aging O-rings and other seals cause the piston to crawl; the piston rod stroke is too long and the gate is stuck in the valve body; coforeign rps are mixed in the cylinder; the connection between the piston and the piston rod is worn; the inner wall of the cylinder is worn and the internal leakage increases; the piston is worn and the cylinder is worn; the pressure entering the cylinder fluctuates too much.

Solution: The gasket should be checked and replaced regularly; adjust the piston rod working stroke to make the action normal; remove foreign matter in time and clean it, and a filter mechanism can be installed in front of the cylinder; The cylinder body must be repaired or replaced; the pressure entering the cylinder must meet the requirements of the specification.

9. Electrical appliance failure or valve failure

Build quality reasons: Improper assembly, leading to overtorque damage; abnormal travel switch setting; torque limiting mechanism failure; signal The signal systemistation is out of service; the operating switching mechanism is out of order.

User\'s reasons: poor lubrication, foreign matter in the valve, resulting in overtorque damage; engine failure.

Solution: Oil should be added and kept clean to ensure proper lubrication; packaging should be pressed moderately; foreign objects in the valve must be removed in time; the motor working time should not exceed 15 minutes, the power supply should be normal, and the motor should be protected from moisture.

10. Leaking valve body and valve bonnet. the welded parts have defects such as slag inclusions and incomplete penetration stress cracks.

User Reasons: Compression or impact damage; frost cracking.

Solution: Do not stack and store, do not hit valvese and non-metallic, use brackets to install large diameter valves; when the temperature is below 0°C, insulation measures should be taken; Valves out of service must be removed from the water.

11. Electromagnetic valve failure tic transmission device failure

Build quality reasons: falling wires; parts are loose and improperly installed; It leaks into the coil, causing poor insulation and burning the coil.

Prev: Causes of Vortex Flowmeter Instability in Coke Oven Gas Measurement