The three-valve group is a control component in the fluid delivery system, with functions such as cut-off, regulation, diversion, prevention of backflow, regulation, shunting or overflow relief. Valves for fluid control systems range from the simplest shut-off valves to the wide variety of valves used in extremely complex self-control systems. Valves can be used to control the activity of various types of fluids such as air, water, steam, various aggressive media, mud, oil, liquid metals, and radioactive media.
The connection between the valve and the pipe is an important parameter. According to this classification:
1. Threaded connection: The valve body has internal or external thread and is threadedly connected to the pipe.
2. Flange connection: The valve body is flanged and connected to the pipe flange.
3. Welding connection: The valve body has a welding groove and is welded to the pipe.
4. Clamp connection: The valve body has a clamping mouth and is connected with the pipe clamp.
5. Card sleeve connection: Connect with the pipe with a ferrule.
6. Clip connection: The connection form in which the valve and the two pipes are directly clamped together by bolts.
Three-valve group change adjustment method
The three-valve group utilizes a conical-conical slit type to change the orifice, and the rotating handwheel is used for adjustment.
2, the valve stem 4 is rotated, the valve needle 6 is displaced relative to the valve seat 7 by the thread, thereby adjusting the gap between the mesh needle and the valve seat, and changing the gas resistance value (that is, the throttling effect) The characteristic of the valve is that the valve needle 6 is not rigidly connected to the valve stem 4. Instead, the valve pin shoulder is always pressed against the seat cushion 10 by the compression spring 8. The diameter of the seat cushion hole is larger than the diameter of the valve needle, and the valve needle can be moved on four sides. When the valve needle is in contact with the valve seat, if the valve stem 4 has excessive displacement, the valve needle 6 compresses the spring 8 due to the force of the spring 8 Smaller, it protects the valve pin from the seat. The adjustment of the tab 3 can limit the valve stem 4 from being excessively displaced. In general, the adjusting piece 3 is adjusted to ensure that the valve needle is just sealed under the action of the compression spring a, and that the hand wheel 2 starts to rotate with a small dead end (rotating the hand wheel so that the valve needle just leaves the valve seat) The distance the valve stem moves is called the dead end).
Three valve group application method:
The first step: check that the three-valve equalization valve is to be opened, and the upper and lower pressure valves are closed;
Step 2: Open the high pressure valve and wait a few seconds;
The third step: closing the equalization valve;
The fourth step: open the low pressure valve;