Whether the Universal Valve is operated correctly or not directly affects the service life, is related to the smooth production of equipment and devices, and even the safety of the entire system. After the Universal Valve is installed, the operator should be familiar with and master the structure and performance of the Universal Valve transmission device, and correctly identify the direction, opening mark, and indication signal of the Universal Valve.
The
Check Valve is a Universal Valve operated by a handle and a handwheel. It is a Universal Valve commonly used on equipment pipelines. The rotation direction of its handle and handwheel is clockwise to close, and counterclockwise to open. However, there are also some Universal Valve that open in the opposite direction to the above opening. Therefore, you should check the opening and closing signs before operating.
The handwheel and handle on the Universal Valve are designed according to normal manpower. Therefore, the regulations on the use of the Universal Valve do not allow the operator to use levers and long wrenches to open or close the Universal Valve. If the diameter (length) of the handwheel or handle is less than 320mm, only one person is allowed to operate it. For the handwheel with a diameter ≥320mm, two people are allowed to operate it together, or one person is allowed to operate the Universal Valve with the help of an appropriate lever (generally not more than 0.5m long). . However, it is strictly prohibited to use levers or long wrenches to operate diaphragm valves, pinch valves, and non-metallic Universal Valve, nor is it allowed to close the Universal Valve too hard. Universal Valve such as gate valves and Check Valve must rotate 1/4 to 1/2 turns when closed or opened to the end (i.e. bottom dead center or top dead center) to make the threads more tightly sealed, which is convenient for inspection during operation and avoids twisting. If it is too tight, it will damage the
Valve Parts.
When opening the Universal Valve for steam medium, the pipeline must be preheated first to remove condensation water. When opening, it must be done slowly to avoid water hammer and damage to the Universal Valve and equipment.
Some larger-diameter butterfly valves, gate valves and Check Valve are equipped with bypass valves, which function to balance the pressure difference between the inlet and outlet and reduce the opening force. When opening, the bypass valve should be opened first, and then the large Universal Valve should be opened after the pressure difference on both sides of the Universal Valve is reduced. When closing the Universal Valve, first close the bypass valve and then close the large Universal Valve.
When opening a
Ball Valve,
Butterfly Valve, or
Plug Valve, when the groove on the top surface of the
Valve Stem is parallel to the channel, it indicates that the Universal Valve is in the fully open position; when the valve stem rotates 90° to the left or right, the groove is perpendicular to the channel, indicating that The Universal Valve is in the fully closed position. Some ball valves, butterfly valves, and plug valves are opened when the wrench is parallel to the channel, and closed when the wrench is vertical. The operation of three-way and four-way Universal Valve should be carried out according to the opening, closing and reversing marks. After the operation is completed, the movable handle should be removed.
When operating a Universal Valve, Universal Valve such as gate valves and Check Valve cannot be used as throttle valves. This will easily erode the sealing surface and cause premature damage to the Universal Valve.
Newly installed pipelines, equipment, and Universal Valve have a lot of dirt, welding slag and other debris on their internal surfaces. Dirt is also easy to stick to the sealing surface of the normally open Universal Valve. The slightly open method should be used to allow the high-speed medium to wash away these foreign objects. Close again gently. After several times of slightly opening and closing, it can be rinsed clean.
For gate valves and throttle valves with scales, the fully open or fully closed indicating position should be checked and adjusted. Rising stem gate valves and Check Valve should also remember their fully open and fully closed positions, so as to avoid hitting the dead center when fully open. When the Universal Valve is fully open, you can use the ruler and marks to find that the closing part has fallen off or is resisting foreign objects, so as to troubleshoot.
After some Universal Valve are closed, the temperature drops and the valve parts shrink, causing small gaps in the sealing surface and leakage. In this case, the Universal Valve should be closed again at an appropriate time after closing.
