Applicability of globe valves

Applicability of globe valves

A globe valve is a valve in which the closing member (valve flap) moves along the centerline of the valve seat. According to this form of movement of the valve flap, the change of the valve seat orifice is proportional to the valve flap stroke. Since the stem opening or closing stroke of this type of valve is relatively short and has a very reliable shut-off function, and since the change in the seat orifice is proportional to the travel of the valve flap, it is very suitable for regulating the flow rate. Therefore, this type of valve is very suitable for cutting off or regulating and throttling.

Globe valve flap once removed from the closed position, its seat and flap sealing surface is no longer in contact with each other, so its sealing surface mechanical wear and tear is very small, so its sealing performance is very good, the disadvantage is that the sealing surface may be clamped between the particles in the flow medium. However, if the valve flap into a steel ball or porcelain ball, this problem will be solved. As most of the valve seat and valve flap globe valve is relatively easy to repair or replacement, and in the repair or replacement of the sealing element without the entire valve from the pipeline dismantled, which is very suitable for the valve and pipeline welded into one occasion.

The minimum flow resistance of globe valves is also higher than that of most other types of valves because of the change in the direction of flow of the medium through such valves. However, this situation can be improved depending on the structure of the valve body and the layout of the valve stem relative to the inlet and outlet channels. At the same time. As the globe valve flap open and close between the stroke is small, the sealing surface can withstand multiple opening and closing, so it is very suitable for the need for frequent switching occasions. Globe valve can be used in most media flow system. Has been developed to meet the petrochemical, electric power, metallurgy, urban construction, chemical industry and other sectors of various uses of various forms of globe valve.

The use of globe valves is extremely common, but due to the opening and closing torque is larger, the structure of the length is longer, usually the nominal diameter is limited to 250mm below, there are 400mm, but the selection of the import and export direction requires special attention. Generally 15Omm below the cut-off valve media mostly from the bottom of the valve flap into the 2O0mm above the cut-off valve media mostly from the top of the valve flap into. This is to take into account the closing torque of the valve. In order to reduce the opening or closing torque, generally 2O0mm above the globe valve are set up within the bypass or external bypass valve.