Common problems when using electric control valve

Electric control valve is mainly used in industrial automation, the current industrial automation upgrade, also use more common use of electric control valve, electric control valve has a unique advantage, compared to pneumatic control valve, electric control valve at work Only consume electricity, the environmental protection, but also in accordance with the fast, small structure, light weight. Do not need to use the same with the pneumatic control valve tracheal, installation and operation complicated. The following detailed introduction to the electric control valve in the production of the use of the analysis of the problems: 1, the small opening of the double seat valve oscillation: For the double seat valve its main advantage is the open type, the valve stability Good sex, two-seater valve is a two spool, the lower spool in a flow closed, the valve spool is open, so that when the work of a small opening, the flow-closure of the spool is likely to cause valve vibration , Which is why the double seat valve can not be used for small openings. 2, the straight stroke regulator valve anti-blocking performance and angular stroke valve anti-blocking performance is good: straight stroke valve spool is a vertical throttling, and the medium is the level of flow in and out of the valve cavity flow path must turn around the turn, the valve The flow path becomes quite complex (the shape is inverted "S"). In this way, there are many dead zones that provide space for the precipitation of the medium over time, causing clogging. Angle valve stroke direction is the horizontal direction, the media into the level, the level of outflow, easy to clean media away, while the flow path is simple, medium precipitation space is also small, so the anti-blocking performance of the angular stroke valve. 3, the angular stroke valve to cut off a larger pressure difference: angular stroke valve to cut off the larger pressure, because the medium in the valve spool or the resulting force on the rotary shaft torque is very small, so it can To withstand greater pressure. 4, double seal valve can not be used as a shut-off valve: The advantages of two-seater valve spool is force balance structure, allowing large pressure drop, and its prominent drawback is that the two sealing surfaces can not be both good contact, causing a large leak. If it is artificially and purposely used to cut the occasion, apparently ineffective, even for it made many improvements (such as double seal sleeve valve), is not desirable. 5, straight stroke valve stem smaller: straight stroke valve involves a simple mechanical principle: sliding friction, rolling friction small. Straight travel valve stem up and down movement, the packing a little bit tight, it will be very tight stem package, resulting in greater backlash. To this end, the valve stem is designed to be very small, packing and PTFE friction coefficient is often small PTFE packing, in order to reduce backlash, but the problem is sent stem thin, easy to bend, filler life is short. Solve this problem, the best way is to travel with the valve stem, which is the type of angular travel control valve, the valve stem than the straight travel valve stem thick 2 to 3 times, and the choice of long life graphite packing, stem stiffness Good, long filler life, but the friction torque on the contrary, small backlash.