1. Two-seat regulating valve is easy to oscillate when it is in a small opening working state.

    Why the two-seat regulating valve can not be used with a small opening is determined by its seat structure. Double regulating valve has two spool, the upper spool is in flow open, the lower spool is in flow closed, the valve spool of the regulating valve is in flow open, the stability is better, so when the spool of the two-seat regulating valve is in the small opening range close to the flow closed state, the spool will shock. Therefore, in the selection of regulating valves, it is necessary to avoid the use of two-seat regulating valves in the small opening range.

    2, two-seat regulating valve can not be used as a cut-off valve?

    The spool of the two-seat regulating valve has the advantage of force balance structure, allowing the pressure difference of the valve before and after the valve to be large, because the two sealing surfaces can not be in good contact at the same time, so the leakage is large, and can not play a truncated role in the pipeline, even if the sleeve improvement of the two-seat valve is increased now, but it can not change the limitations caused by the structural design.

    3, the direct stroke control valve and Angle stroke valve blockage resistance comparison?

    The spool of the valve is vertical movement, the fluid is horizontal movement, the flow channel structure in the valve chamber is not straight through, generally in the S-shape, so that the formation of many blind areas, a long time, the medium is easy to form precipitate in these blind areas, and then easy to cause blockage. The spool of the angular stroke valve is in a horizontal rotating motion, and the medium is also in a horizontal flow direction, so it is not easy to exist a dead Angle, and the precipitated material is easy to be taken away by the fluid. Therefore, the anti-blocking performance of the straight stroke valve is much better than that of the Angle stroke valve.

    4. Why is the stem of the straight stroke regulating valve thinner?

    Due to the principle of large sliding friction and small rolling friction. The stem of the straight stroke valve is sliding up and down, which produces greater friction. Therefore, the valve stem is designed to be small and the PTFE filler with a small friction coefficient is used to minimize friction. However, the problems such as thin stem, easy to bend and short packing life are generated.

    5, Angle stroke type valve cut off pressure difference is large?

    Because the resultant force generated by the medium acting on the valve core has a very small torque on the valve shaft, it can withstand a large pressure difference, so the cut-off pressure difference of the angular stroke valve is large.