Hydraulic valves are widely used in water, steam, sewage, papermaking, petrochemical industry, solution and slurry two phase mixed flow medium, and dust gas, granular fluid, powder solid medium transport equipment.
Using hydraulic operation, more convenient for management automation, remote control, equipped with hydraulic signal device, can be used for automatic operation and centralized control.
Advantages of hydraulic valves:
1) Simple structure, compact and small volume;
2) Stable and reliable transmission;
3) A large output torque can be obtained;
4) The output torque can be accurately adjusted through the constant pressure relief valve, including the adjustment of opening and closing torque, and can even be directly reflected by the hydraulic instrument;
5) Convenient speed adjustment;
6) In case of sudden power failure, the accumulator can still be used for one or several power operations.
This is of special significance to automatic emergency cut-off valve and wellhead blowout valve in long – distance pipeline.
Disadvantages of hydraulic valves:
1) The oil temperature is greatly affected by the ambient temperature, and the change of oil temperature causes the change of oil viscosity, which affects the operation;
2) Troublesome piping, easy leakage;
3) It is not suitable for generating various operations on the signal (such as signal amplification, memory, logical judgment and other operations).
Advantages of hydraulic system:
1. Small size and light weight;
2. High stiffness, high precision and fast response;
3. Large driving force, suitable for heavy load direct driving;
4. Wide speed control range and various speed control modes;
5. Self-lubrication, self-cooling and long life;
6. Easy to realize security protection.
Disadvantages of hydraulic system:
1. Poor resistance to working fluid pollution;
2. Sensitive to temperature changes;
3. Hidden danger of leakage;
4. Difficult manufacturing and high cost;
5. It is not suitable for long-distance transmission and requires hydraulic energy.