What Are the Structural Classifications of Gate Valves?

There are many different ways to classify the gate valve structure, the main difference is the different structural forms of the sealing elements used. According to the structure of the sealing element, the gate valve is often divided into several different types, and the most common gate valve types are parallel gate valve and wedge gate valve. According to the structure of the valve stem, it can also be divided into rising stem gate valve and dark stem gate valve.

1. Parallel gate valves

The two sealing surfaces of the parallel gate valve are perpendicular to the axis of the pipeline, that is, the gate valve with the two sealing surfaces parallel to each other. Among the parallel gate valves, the structure with a thrust wedge is the most common, and the parallel gate valve is suitable for low pressure, medium and small diameter valves. The spring can generate the necessary pre-compression force, which is beneficial to the sealing of the gate. In addition, there are parallel gate valves with mechanical devices (such as levers, screw mechanisms, etc.) to push the gate open, and one-way parallel gate valves with only one sealing pair. These structures are currently only used under special working conditions.

2. Wedge gate valves

The two sealing surfaces of the wedge gate valve form a certain angle with the axis of the pipeline, that is, the gate valve in which the two sealing surfaces are wedge-shaped. The size of the inclination angle mainly depends on the temperature of the medium. Generally, the higher the working temperature, the larger the angle should be to reduce the possibility of wedging of the gate when the temperature changes. In the wedge gate valve, it can be divided into double gate, single gate and elastic gate.

3. Rising stem gate valves

The valve stem nut of this kind of gate valve is set on the valve cover or bracket. When opening and closing the valve, the valve stem nut is rotated to realize the lifting and lowering of the valve stem. In this structure, the threaded part of the valve stem is not in contact with the medium, and is not easily corroded by the medium, and at the same time is beneficial to the lubrication of the threaded part of the valve stem, so it is widely used. Contact GEKO, a professional gate valve supplier, for the gate valve price.

4. Dark stem gate valves

The valve stem nut of this kind of gate valve is in direct contact with the medium in the valve body. When opening and closing the valve, it is realized by rotating the valve stem. The only advantage of this structure is that the height of the gate valve does not change when opening and closing, so the gate valve installation space is small. However, this type of valve must be equipped with an opening and closing indicator to display the opening of the valve.

At present, in petroleum and chemical systems, especially in long-distance oil and natural gas pipelines, flat gate valves with floating valve seats are widely used. This kind of flat gate valve has low fluid resistance, reliable sealing performance and long service life. This type of gate valve is divided into guide holes and without guide holes. The flat gate valve with diversion hole is mainly used in oil and natural gas pipelines to clean the pipeline, and the flat gate valve without diversion hole is suitable for opening and closing devices on various pipelines. The manufacturing process of this gate valve is relatively simple, and it is easy to realize automatic production.