What Is the Flow Direction of Globe Valves?

Many people think that instrument valves are that the place of flowing out is high than that of flowing in, but this is not true. In general, the flow in globe valve is from the lower part to the higher part, but there are some special cases where the globe valve is from the higher part to the lower part.

Common Globe Valves

Welded globe valve is designed to flow from low place to high place, and the purpose is to make the flow resistance small and save effort when opening the valve. At the same time, when the valve is closed, the gasket between the valve housing and the bonnet and the packing around the valve stem are not stressed, and will not be exposed to the effects of medium pressure and temperature for a long time, which can prolong the service life and reduce the probability of leakage. In addition, the packing can be replaced or added while the valve is closed for easy maintenance.

Special Globe Valves that Flow from Low Places to High Places

1.High Pressure Globe Valve with A Diameter Greater than 100mm

Due to the poor sealing performance of large-diameter valves, in the closed state of this valve, the medium pressure acts on the valve flap to increase the valve's tightness.

2.With Two Globe Valves Connected in Series on the Bypass Pipeline, the Second Globe Valve Requires Flowing from Low Places to High.

In order to ensure the tightness of the valve in a maintenance cycle, the valve that is often opened and closed requires two series of globe valves. For the bypass system, the installation of this bypass has three functions. Firstly, balance the front and rear pressure of the main pipeline valve, making it easy to open and save labor, reducing wear and tear of the main pipeline valve. Secondly, warm pipe during startup with small flow. Thirdly, on the main feed water pipeline, control the feed water flow to control the boiler boost speed for boiler water pressure test.

According to the medium flow direction, the bypass stop valves include a primary valve and a secondary valve. The primary valve and the secondary valve are closed during normal operation of the unit, and both are in direct contact with the medium. In order to prevent the gasket between the secondary valve housing and valve cover and the packing around the valve stem from being affected by medium and temperature for a long time, and the valve packing can be replaced during operation, the required installation direction of the secondary valve is flowing from low places to high ones.

3.Boiler Exhaust and Vent Stop Valve

Boiler exhaust and vent stop valves are only used in the process of starting and feeding water to the boiler. The frequency of opening and closing is small, but the working fluid is often lost due to inadequate sealing. Some power plants have installed globe valves that flows from low places to high ones in order to improve the tightness.

4.Electromagnetic Quick-release Valve

The function of the electromagnetic quick-off valve is to close quickly and cut off the fuel supply quickly. The structure of the electromagnetic quick-disconnect valve is similar to that of the globe valve. If the electromagnetic quick-disconnect valve also flows from the lower part to the upper part, the force of the fuel acting on the lower part of the valve of the electromagnetic quick-disconnect valve is large. Therefore, it is better to choose the method of flowing from low places to high places.

If valve that flows from low places to high ones is used in high-pressure and large-caliber conditions, the valve stem is easily deformed and bent under long-term water pressure, which affects the safety of the valve. While in other special conditions, the valve that flows from low places to high places is safer and saves more money. It all depend on your needs for which one to choose.