The globe valve is designed with low inlet and high outlet to reduce flow resistance and save effort when opening the valve. When the valve is closed at the same time, the gasket between the valve shell and valve cover, as well as the packing around the valve stem, are not subjected to force and will not be affected by medium pressure and temperature for a long time. This can prolong the service life and reduce the probability of leakage. In addition, this can also replace or add packing when the valve is closed, making maintenance easier.

Many people believe that globe valves are low in and high out, but in fact, they are not. In general, globe valves are low in and high out, but there are also some special cases where globe valves are high in and low out:

1. High pressure shut-off valves with a diameter greater than 100mm

Due to the poor sealing performance of large-diameter valves, this method is used to increase the sealing performance of the valve by applying medium pressure above the valve disc when the shut-off valve is in a closed state.

2. Two shut-off valves connected in series on the bypass pipeline, the second shut-off valve requires "high inlet and low outlet"
    To ensure the tightness of the valve within a maintenance cycle, valves that frequently open and close require the installation of two series connected globe valves. For the bypass system, the installation function of this bypass is:

① Balance the pressure before and after the main pipeline valve, making it easy and labor-saving to open, and reducing the wear of the main pipeline valve;

② Heating pipes with small and medium flow during startup;

③ On the main water supply pipeline, control the water flow rate to control the boiler pressure rise speed for boiler water pressure testing. According to the direction of medium flow, the bypass shut-off valves are the primary valve and the secondary valve, respectively. During normal operation of the unit, the primary valve and the secondary valve are closed, both of which come into direct contact with the medium. To prevent the gasket between the secondary valve shell and valve cover, as well as the packing around the valve stem from being exposed to medium and temperature for a long time, and to replace the valve packing during operation, the installation direction required for the secondary valve is "high in, low out".

3. Boiler exhaust and vent shut-off valves

The boiler exhaust and vent shut-off valves are only used during the water supply process during boiler startup, with a small opening and closing frequency. However, they often cause fluid loss due to poor sealing. Therefore, some power plants install such shut-off valves in a "high inlet and low outlet" direction to improve tightness.

4. Electromagnetic quick break valve

The function of the electromagnetic quick stop valve is to quickly close and cut off the fuel supply. The structure of an electromagnetic quick break valve is similar to that of a globe valve. If the working fluid also enters from the bottom and flows out from the top, the force of fuel acting on the lower part of the electromagnetic quick break valve disc is significant, and the weight of the electromagnetic quick break valve is much smaller than it. Therefore, if the working fluid enters the quick cut-off valve from the bottom, the torque generated by the heavy hammer is less than the torque generated by the fuel pressure. When the quick cut-off valve acts, the fuel cannot be cut off, and thus the expected purpose cannot be achieved. If the working fluid enters from the upper part of the quick break valve, due to the rapid decrease in pressure behind the valve once the quick break valve is activated, the force of fuel acting on the lower part of the valve disc quickly decreases to zero, while the force of fuel acting on the valve disc and the force formed by the gravity of the hammer and lever.

It is difficult to close the valve when using low inlet and high outlet in general large-diameter and high-pressure conditions. If using low inlet and high outlet in high-pressure large-diameter conditions, the valve stem is prone to deformation and bending due to long-term water pressure, which affects the safety and sealing of the valve; If high and low positions are selected, the diameter of the valve stem can be reduced, which will also save some costs for manufacturers and users.