In pipeline systems, globe valves and gate valves are two common types of valves. They have some differences in structure, flow direction, sealing surface, opening and closing components, and flow direction. This article will provide a detailed introduction to the differences and advantages and disadvantages of globe valves and gate valves, helping you better understand the differences and application scenarios of these two types of valves.
1、 Different structures
The structure of the globe valve is relatively simple, with a small volume, light weight, less material consumption, and convenient installation and maintenance. However, the tightness of the globe valve is poor. If its working principle relies on the pressure of the valve stem to tightly press the valve disc, its sealing performance is not very ideal.
The structure of gate valves is more complex than that of globe valves, with a larger volume and greater resistance to water flow. There are many types of gate valves, which can be divided into two types according to the length of the valve stem: open stem and concealed stem. The handwheel is not exposed outside, and to open and close as usual, the support must be opened, which is not lightweight enough.
2、 Different flow directions
Globe valves can only perform unidirectional flow in pipelines, hence they are also known as one-way valves. Globe valves have low flow resistance, making opening effortless and closing without adding support force. However, globe type control valves composed of globe valves may experience oscillation when using flow regulation.
Gate valves can perform bidirectional flow in pipelines, so they are also called bidirectional valves. Gate valves have low flow resistance, making opening effortless and closing without adding support. However, gate type regulating valves composed of gate valves may experience oscillation when using flow regulation.
3、 Different sealing surfaces
The sealing surface of a globe valve refers to the static (linear) seal between the valve disc and the valve seat, as well as the dynamic (linear) seal between the valve disc and the packing box (sleeve). The shape, material, and processing quality of the sealing surface directly affect the sealing performance and service life of the globe valve.
The sealing surface of a gate valve generally adopts a metal to metal sealing structure. In some cases, non-metallic to metal and metal to non-metallic sealing structures can also be used. The sealing pair of the gate valve (gate plate and valve seat) is in a periodic opening and closing process in the closed state. Due to periodic friction and impact, the metal to metal sealing method is prone to causing scratches on the sealing surface and surface fatigue failure, leading to a decrease in sealing performance.
4、 Different opening and closing components
The opening and closing components of a globe valve are a plug shaped valve disc and a disc shaped valve seat, whose main function is to cut off or connect the medium flow. When in the fully open position, the weight of the medium flows again, causing a downward trend, which can automatically prevent lively compression and ensure reopening.
The opening and closing components of a gate valve are the gate plate (collectively referred to as the individual opening and closing components). The movement direction of the gate plate is perpendicular to the direction of the fluid, and can only be fully open and fully closed. It cannot be adjusted or throttled. The gate plate has two sealing surfaces that can act simultaneously (processed) or independently (formed in one processing). If the processing materials of the two sealing surfaces are the same (processed with the same material at the same time), good sealing effects can also be achieved.
5、 Different flow directions
The structure of the shut-off valve determines that it is a clockwise shut-off valve (to facilitate user operation, the pneumatic actuator drives the valve to rotate 90 degrees in a clockwise direction to close the valve). Its flow direction is that the pressure of the medium increases (to the left) and decreases. Its flow direction is perpendicular to the direction of the medium change.
The structure of a gate valve determines that the pressure of the medium increases as it moves upwards (to the right). Its flow direction is that the pressure of the medium decreases as it moves downwards (to the left) (to the left). Its flow direction is parallel to the direction of the medium change.
I hope that through the introduction in this article, you have a deeper understanding of the difference between globe valves and gate valves. In practical applications, you can choose the appropriate valve type according to different needs and occasions to achieve better usage results. If you have any other questions or need further assistance, please feel free to contact us at any time.
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