Gate valve types

Gate valve type
1. The type of gate valve can be divided according to the plan of the gate

A. Parallel gate valve: The sealing surface is parallel to the vertical base line, that is, the gate valves whose two sealing surfaces are parallel to each other. Among the parallel gate valves, the plan with thrust wedges is most common, and there are double-sided thrust wedges at the two gate bases. This gate valve is suitable for low-pressure medium and small diameter (DN40-300mm) gate valves. There is also a spring between the two shutters, and the spring can exert a tightening force to facilitate the sealing of the shutter.

B. Wedge gate valve: The sealing surface is at an angle to the vertical base line, that is, the gate valve with two sealing surfaces forming a wedge shape. The angle of inclination of the sealing surface is usually 2°52′, 3°30′, 5°, 8°, 10°, etc. The size of the angle depends mainly on the unevenness of the medium temperature. Generally, the higher the working temperature, the larger the angle should be taken to reduce the possibility of wedges when temperature changes. In the wedge gate valve, there are also single gate, double gate and elastic gate. The single-gate wedge gate valve has simple planning and reliable operation, but the precision of the cover angle is high, the processing and repair are difficult, and the wedge can be greatly changed when the temperature is changed. Double gate wedge gate valves are used more in water and steam medium lines. Its benefits are: the accuracy of the angle of the sealing surface needs to be low, the temperature change is not easy to cause the wedge to be seen, and when the sealing surface is worn, it can be compensated. However, there are many such planned parts, which are easy to bond in the viscous medium and affect the sealing. More importantly, the upper and lower baffles are prone to rusting for a long time, and the rams are simply dropped. Elastic gate wedge gate valve, which has a simple plan of single gate wedge gate valve, can be used for a small amount of elastic deformation to compensate for the deviation of the sealing surface angle during processing, and improve the technicality.

2, the type of gate valve can be divided into the gate valve according to the valve stem.

A. Open gate valve: The stem nut is on the bonnet or bracket. When opening and closing the gate, use the rotary stem nut to complete the lift of the stem. This kind of planning is beneficial to the lubrication of the valve stem, and the degree of opening and closing is obvious, so it is widely used.

B. Dark rod gate valve: The stem nut is in the valve body and touched directly with the medium. When opening and closing the shutter, use a rotary valve stem to complete. The benefit of this type of planning is that the height of the gate valve is always constant, so the equipment has a small space and is suitable for large-diameter or gate valves that are constrained by equipment space. Such planning should be equipped with an opening and closing indicator to indicate the degree of opening and closing. The disadvantage of this type of planning is that the stem threads are not only lubricated, but also directly subject to media erosion and are simply damaged.

3, gate valve according to the material is also divided into cast iron gate valve, cast steel gate valve, stainless steel gate valve, chrome molybdenum steel gate valve, chrome vanadium steel gate valve, plastic gate valve.