Electric valve common problems teach you the accurate selection of electric valve and pneumatic valve and the advantages and disadvantages of two kinds of valves

Electric valve common problems teach you the accurate selection of electric valve and pneumatic valve and the advantages and disadvantages of two kinds of valves

Effect of scale

Whether solenoid valve or electric valve, scale will not only cause valve leakage, severe even affect the normal work of the valve, so how to eliminate the impact of scale, has become the common concern of the industry.

Control valve function is poor

Solenoid valve process to involve the scope is too wide, but because the design of the actuator and the use of filling materials caused by the poor function of the control valve can still be summarized its rules.

The presence of dead zones in the process will cause the process variable to deviate from the original set point. So the output of the controller must be increased enough to overcome the dead zone for this corrective action to occur.

Main factors affecting the dead zone:

① Friction, drift, valve shaft torsion, amplifier dead zone. Control valves are sensitive to friction in different ways. Rotary valves, for example, are sensitive to friction caused by high seat load, so be aware of this when using. For some seals, however, a high seat load is necessary to achieve the seal class. As a result, the valve is poorly designed and easily causes a large dead zone, which has an obvious and almost decisive effect on the degree of process deviation.

② Wear and tear. Valve wear is inevitable in normal use, but the wear of the lubrication layer is severe, according to the experimental proof, lubricating rotary valve only through hundreds of reincarnation of action, lubrication layer can barely be used. In addition, pressure-induced load can also lead to seal wear, which is a major factor in increasing friction. The result is a destructive control valve

(3) Packing friction is the main source of control valve friction, the use of different packing, resulting in a great difference in friction.

(4) Different types of actuators also have a fundamental impact on the friction force. Generally speaking, spring film actuators are better than piston actuators.

Teach you the accurate selection of electric valve and pneumatic valve and the advantages and disadvantages of two kinds of valves Electric valve driven by electricity, in the explosion-proof requirements of the occasion is not suitable, like the nearby environment with a large number of easily dyed gas, you can only rely on pneumatic. Pneumatic response time is slower than electric, not as accurate as electric, pneumatic valve is pneumatic power. The electric valve is converted into electromagnetic energy as the power, the agility of the electric valve is higher than that of the pneumatic valve, the safety and reliability is not as strong as the pneumatic valve, the maintenance is not as simple as the pneumatic valve, the power is not as strong as the pneumatic valve.

1. Electric valve uses motor as power, and pneumatic valve uses compressed air as power.

1. Advantages of electric valve: Good effect on liquid medium and large diameter gas, not affected by weather. Not affected by air pressure.

Disadvantages: high cost, not good in humid environment.

2. Advantages of pneumatic valve: Good effect on gas medium and small diameter liquid, low cost and easy maintenance.

Disadvantages: Affected by the fluctuation of air pressure, it is easy to be affected by air pressure and air water in the northern winter, resulting in freezing and no action of the transmission department.

How to choose electric valve and pneumatic valve accurately

Two, the general pneumatic is faster than electric, electric is dual use flashlight. And pneumatic to hand, gas dual-use price is relatively high.

Three, the electric valve is used in some large diameter places, because the pneumatic is difficult to do, but the electric valve is not as chaotic as the pneumatic, the switching speed is slow, the actuator will be stuck for a long time. Pneumatic valve switch fast, high precision, but need not chaos of the air source.

Four, the electric valve action slow electric valve can do explosion-proof brand is not many; Pneumatic valve action is rapid, explosion-proof relative price than electric bottom (hub pneumatic valve with what accessories, with big brand accessories will be more expensive than electric valve).

The valves involved in interlocking are also electric. Why?

1, according to the local weather, if the weather is wet, the pneumatic valve can not be used, because the air source is with water.

2, the electric valve can also realize the interlocking function without additional increase in usage, pneumatic interlocking will increase the retaining valve, increase the cost.

Advantages and disadvantages of electric valve and pneumatic valve:

Under what circumstances need to use electric valve without pneumatic, when the need to use pneumatic without electric valve, between them what advantages and disadvantages, the price. The pneumatic valve action distance is larger than the electric valve, the pneumatic valve switch action speed can be adjusted, simple structure, easy to maintain, in the process of action because of the buffer characteristics of the gas itself, not easy to be damaged by jamming, but must have the air source, and its control system is more complex than the electric valve.

The electric valve is driven by electricity, which is not suitable for the occasion of explosion-proof requirements. When a large number of easily dyed gases are dispersed in the nearby environment, it can only rely on pneumatic. Pneumatic response time is slower than electric, not as accurate as electric, pneumatic valve is pneumatic power. The electric valve is converted into electromagnetic energy as the power, the agility of the electric valve is higher than that of the pneumatic valve, the safety and reliability is not as strong as the pneumatic valve, the maintenance is not as simple as the pneumatic valve, the power is not as strong as the pneumatic valve.

The control of pneumatic valve is more complex than that of electric valve. And the cost is very expensive, if it involves automatic control, it is necessary to add the electromagnetic reversing valve, and the agility of the electromagnetic reversing valve directly affects the pneumatic valve. I prefer the first floor.

Electric valves can be used as long as electricity is available. In some factories, many tools and equipment use compressed air. In this case, pneumatic valves may be used, since they are readily available. The response is quick, safe and reliable, many factories with high control requirements are designed for pneumatic instrument control elements to set up compressed air station. Electric means electric. The pneumatic valve is significantly better than the electric valve, but the air source is so bad that the electric valve is used in the place of the air source.