The valve is an important part of the thermal system, operators often have to deal with the valve, so the best familiar with and master the structure and performance of the valve, the correct identification of the valve direction, opening mark, indicating signals, should be able to skillfully and accurately adjust and operate the valve timely and decisively deal with a variety of emergency failures. Pay attention to the following types of operations:
1. Identify the switch direction of the valve. General manual valve, the hand wheel clockwise rotation direction indicates the direction of valve closing, counterclockwise direction indicates the direction of valve opening, some valve direction is opposite to the above opening and closing, should check the opening and closing signs before operation, the plug valve stem top surface of the groove is parallel to the channel, indicating the valve in the fully open position, when the valve stem rotates 90°, the groove is perpendicular to the channel. It indicates that the valve is in the fully closed position, and some plug valves are opened with the wrench and the channel flat, and the vertical is closed. Three-way and four-way valve operation should be carried out according to the mark of opening and closing reversing.
2. Force should be appropriate, when operating the valve, too much force is easy to damage the handle, handwheel, scratch the valve stem and sealing surface, and even crush the sealing surface, do not use a big wrench to open and close the small valve, to prevent excessive force and damage the valve.
3. Before opening the steam valve, ** first preheat the pipe to exclude condensate water, and open it slowly to avoid water hammer phenomenon and damage the valve and equipment.
The larger diameter valve is provided with a bypass valve. When opened, the bypass valve should be opened first, and the large valve should be opened after the pressure difference between the two sides of the valve is reduced. When closing, first close the bypass valve, and then close the large valve.
Gate valve, globe valve type valve to open the end, to turn 1/4-1/2 circle, conducive to operation inspection, so as not to screw too tight, damage the valve.