How to Close Gate Valve

Date: Apr 22, 2024 15 views Source: VALTEC China Valve Manufacture CO.,LTD

Understand the gate valve closing method

1.Close the manual gate valve

Manual gate valve closing is the more common method. When it is necessary to close the gate valve, the handle needs to be rotated to press the gate downward and rely on the surface sealing of the sealing pair to cut off the flow of the medium in the pipeline.

2.Close the electric gate valve

Large gate valves are usually closed electrically. When the electric gate valve is closed, the motor drives the gate plate to move downward, thereby cutting off the flow of the medium in the pipeline. The electric mode can be controlled by remote control or automation system to improve production efficiency and safety.

Gate valve switch diagram — **Gate valve closed and opened**

Under normal circumstances, gate valves are closed clockwise and open counterclockwise. There will be special markings under special circumstances.

When the gate lift height is equal to 1:1 times the valve diameter, the fluid channel is completely unobstructed, but this position cannot be monitored during operation. In actual use, the top of the valve stem is used as a mark, that is, the position that does not open, as its fully open position.

Precautions for closing gate valve

1. Correct operation

Before closing the gate valve, please confirm that the medium has been introduced into the storage chamber or buffer zone. The correct operation of the gate valve is to rotate the handle to the closed position and ensure that the sealing surface is in close contact before closing the gate.

2. Prevent excessive shutdown

When closing the gate valve, avoid over-closing the gate. If it is closed excessively, it may cause the friction between the sealing surfaces to increase, leading to seal failure.

3. Prevent media accumulation

After long-term operation, the medium in the pipeline may be deposited between the gate plate and the valve seat, causing the gate valve to not be completely sealed when closed. Therefore, regular inspection of the pipeline and cleaning of accumulated debris and media around the valve can ensure the normal closing and service life of the valve.

Gate valve FAQ

How to tell whether a gate valve is open or closed?

Unlike some other flow valve types, it is not always easy to tell whether a gate valve is open or not.
Because the gate valve’s handwheel is located above or to the side of the pipe and rotates 360 degrees to open and close the valve, you can’t tell which position they are based on a glance.
Normally, turning the gate valve counterclockwise will open it, while turning the gate valve clockwise will close it. These directions are usually marked on the handwheel or elsewhere on the valve housing.

Why does the gate valve need to return half a turn?

The closing and opening of the gate valve require the movement of the gate, and the opening or closing of the gate requires a certain angle of rotation. The half turn is to ensure the sealing and stability of the valve.
At the same time, the steel material has a certain degree of elasticity, and the half turn is to prevent exceeding its elastic deformation range and causing damage to the screw rod.

Why can't the gate valve close?

1. The sealing surface of the gate valve is damaged: If the sealing surface of the gate valve is damaged or contains impurities, it will cause the seal to be loose and the gate valve cannot be completely closed.
2. The gate valve stem or nut is loose: If the gate valve stem or nut is loose, the gate cannot be completely closed.
3. Internal structural failure of the gate valve: If the internal parts of the gate valve, such as sealing rings, springs, etc., are damaged or loose, it will also affect the closing of the gate valve.

For the specific operation of the gate valve’s opening and closing, it is recommended to refer to the gate valve’s instruction manual or consult VALTECCN VALVE’s relevant professionals.

VALTECCN is a China gate valve manufacturer. If you need to purchase China gate valves, please contact us for a quote and we will respond within 24 hours.

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