Why is the gate valve not suitable for regulating flow?

As a common pipeline control valve, the gate valve is widely used in water, electricity, gas and other fields for pipeline switch control. Its main function is to fully open or fully close the fluid channel in the pipeline to achieve medium flow control. Due to its unique design, the valve is very suitable for cutting off the flow, but it has significant limitations in flow regulation. So why is the valve not suitable for regulating flow? This article will analyze the shortcomings of the valve in regulating flow from multiple aspects.

1.Working principle and design features of the stainless steel gate valve

The main working principle of the valve is to control the passage of fluid by raising and lowering the valve disc. The valve disc is usually perpendicular to the flow channel, and the valve disc is moved up and down by rotating the valve stem to control the opening degree of the pipeline channel. The design goal of the valve is to achieve a fully open or fully closed state. When the valve is open, the flow channel is completely unobstructed; when it is closed, the valve disc is tightly sealed with the valve seat to prevent the flow of the medium.

This design feature makes the valve very effective between **fully open** and **fully closed**, but there are some problems in the **partially open** state that make it unsuitable for precise flow regulation.

2. Unstable flow when partially open

**Inaccurate flow control**:

The gate valve's disc is in vertical contact with the flow channel, and when the valve is partially open, the flow pattern of the fluid changes dramatically. Due to the large contact area between the disc and the flow channel, the fluid flow is more restricted. Even a slight change in the disc position can cause large fluctuations in flow. In contrast, flow control valves such as ball valves and butterfly valves can smoothly control the flow by adjusting the angle of the valve core, so valves are difficult to achieve precise flow regulation effects.

**Uneven flow distribution**:

When the flange gate valve valve is in a partially open state, the fluid will be unevenly distributed around the disc, and there will be a large difference between areas with higher flow velocity and areas with lower flow velocity. This uneven flow will cause the flow of the medium to be blocked, which will affect the flow stability of the entire pipeline system. In the fully open state, there is no such problem when the fluid passes through the valve.

3. Increased flow resistance during opening and closing

The contact area between the valve disc and the flow channel of the valve is large. When the valve is partially opened, the valve disc will produce greater resistance to the fluid, especially in the case of medium and low flow. The friction between the fluid and the valve disc is large, which can easily cause poor fluid flow and even produce vortex, vibration and other phenomena. In order to maintain a stable flow, the valve needs to withstand a large pressure difference, which will not only cause damage to the valve, but also affect the normal flow of the fluid.

When the valve is opened slightly, the flow rate changes are usually very drastic, and the flow path of the fluid is seriously affected, causing the flow rate regulation to become unstable. Therefore, it is difficult to control the flow of the valve in a partially open state, and it is not easy to adjust accurately.

4. Wear of the valve disc and the sealing surface

Due to the large contact area between the valve disc and the sealing surface of the flat gate valve, the sealing surface will be subjected to greater wear pressure when the valve is partially opened or closed. During the long-term partial opening operation, the friction between the valve disc and the valve seat will intensify, resulting in a decrease in sealing performance. This wear not only reduces the service life of the valve, but also causes valve leakage, which in turn affects the accuracy of flow control.

In contrast, regulating valves such as ball valves and butterfly valves usually do not have such problems because they have less contact between sealing surfaces and less friction, which can provide longer flow regulation stability.

5. Vibration and noise are easy to generate during the regulation process

When the valve is used for partial opening regulation, turbulence and eddy currents are easy to generate when the fluid passes through the valve, which not only increases the energy consumption of the system, but also may cause pipeline vibration and noise. Since the fluid flow is unstable when the valve is partially opened, pressure fluctuations may occur near the valve, causing vibration, further affecting the stability of the pipeline system. Therefore, valves are generally not recommended for fine flow regulation.

6. Applicable occasions for gate valves

Water gate valve are more suitable for occasions that require **full opening** or **full closing**, such as pipeline switch control and isolation control. It is widely used in the flow control of media such as water, gas, and oil, especially in those systems where the flow demand is relatively constant and does not require frequent adjustment.

For occasions where flow regulation is required, it is recommended to use **ball valve**, **butterfly valve**, **regulating valve**, etc. These valves are designed to be more suitable for precise control in a partially open state, and can be smoothly adjusted according to the needs of fluid flow, providing higher flow control accuracy.