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Which is better, ‘low in, high out’ or ‘high in, low out’ for globe valves?

Release time:

May 20,2025

Which is better, ‘low in, high out’ or ‘high in, low out’ for globe valves?

The globe valve is designed as low inlet and high outlet, the purpose is to make the flow resistance is small, when opening the valve to save energy. At the same time, when the valve is closed, the valve shell and valve cover gasket and packing around the valve stem is not subject to force, not to be subjected to media pressure and temperature for a long time by the role of the service life can be extended to reduce the chance of leakage. In addition, this can also be replaced in the state of the valve closed or add packing, easy maintenance.

Many people think that the globe valve is low into the high out, in fact, not. In general, globe valves are low into the high out, however, there are some special cases of globe valves are high into the low out:

1,Diameter greater than 100mm high pressure globe valve, due to the large diameter valve sealing performance is poor, using this method of globe valve in the closed state, the media pressure acts on the valve flap above to increase the sealing of the valve.

2,Bypass pipeline in series with two shut-off valves, the second shut-off valve requires ‘high in low out’, in order to ensure that a maintenance cycle of the valve tightness, often open and close the valve requires the installation of two series of shut-off valves. For the bypass system, this bypass is equipped with the role of:

①Balance the pressure before and after the main pipeline valve, so that it is easy to open and save energy, and reduce the wear and tear of the main pipeline valve;

②Start-up process of small flow warming pipe;

③On the main water supply pipeline, control the feed water flow to control the boiler boosting speed for boiler water pressure test. According to the direction of media flow bypass shut-off valves are primary and secondary valves, primary and secondary valves are closed during normal operation of the unit, both of which are in direct contact with the media. In order to prevent the secondary valve shell and valve cover between the gasket and the valve stem around the packing for a long time by the media and temperature, as well as in the process of operation can be replaced valve packing, the secondary valve requires the direction of the installation of the ‘high into the low out’.

3,Boiler exhaust, venting globe valve, boiler exhaust, venting globe valve is only used in the boiler start-up water process, opening and closing frequency is small, but often due to sealing is not tight and cause loss of quality, in order to improve the tightness of the power plant will be installed in the direction of such a globe valve, ‘high into the low out’.

4,Electromagnetic quick-break valve, electromagnetic quick-break valve function is to quickly close, quickly cut off the fuel supply. Electromagnetic shut-off valve structure and shut-off valve structure is similar, if the electromagnetic shut-off valve is also from the lower part of the mass into the upper part of the outflow, then the fuel in the electromagnetic shut-off valve valve flap lower force is very large, and the electromagnetic shut-off valve weight is much smaller than it. Therefore, if the workpiece from the lower part of the quick disconnect valve, the moment generated by the weight is less than the moment generated by the fuel pressure, when the quick disconnect valve action can not cut off the fuel, thus failing to achieve the desired purpose. If the workpiece from the upper part of the quick disconnect valve into, due to the quick disconnect valve once the action of the valve, the pressure behind the valve is rapidly reduced, the fuel acting on the lower part of the valve flap of the force is quickly reduced to zero, while the fuel acting on the valve flap of the force and the weight of the hammer, the lever's gravity of the formation of the force.

General large diameter and high pressure state using low into the high out if the valve is more difficult to close, if the state of high pressure and large diameter using low into the high out, the valve stem is subject to long-term water pressure is easy to deformation and bending, affecting the safety of the valve and sealing; selection of the high into the low, if the stem diameter can be small, for manufacturers and users will also save some cost.

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