Valve repair and installation-3

Release time:

2024-03-23

What are the components of the valve?

Answer: the valve, which is an open and close valve, is mainly composed of valve body, open and close components and valve cover. The valve seat is on the valve body, the valve stem drives the valve opening and closing parts (valve disc) to do lifting movement, and the clutch between the valve disc and the valve seat makes the valve open and close.

The opening and closing mechanism is composed of valve disc (also known as valve disc and valve core), valve rod and driving device (hand wheel). The valve stem is screwed on the valve cover with trapezoidal thread, and the handwheel and disc are fixed on the upper and lower ends of the valve stem. Rotate the handwheel, the valve stem can be raised or lowered, so as to drive the disc close or leave the valve seat to close and open. The disc and the valve seat are closely matched, and the valve disc is tightly pressed on the valve seat by the pressure of the valve stem. At this time, the valve is completely closed, and the valve is tight.

The function of the valve cover part is to ensure that the combination part of the valve stem and the valve body is tight without leakage. There is packing (also known as packing) in the combination part of the valve cover and the valve stem, which is pressed by the packing gland to ensure that the medium does not leak when the valve stem is rotating.

How to install the valve?

Answer: the installation requirements of the valve are as follows.

1) During the loading, unloading and handling of the valve, it is not allowed to throw it at will to avoid damage.

2) When stacking valves, they shall be classified and stacked separately according to different specifications and models; it is forbidden to stack carbon steel valves together with stainless steel valves and non-ferrous metal valves.

3) When hoisting the valve, the rope shall be tied at the flange connection between the valve body and the valve cover. Do not tie on the handwheel or stem to avoid damaging the stem and handwheel.

4) When installing the valve on the horizontal pipeline, the valve stem shall be vertical upward, and it is not allowed to install the valve stem downward.

5) When installing the valve, it is not allowed to use the forced butt joint method of pulling hard to avoid damage due to uneven stress.

6) Open stem gate valve should not be installed in the underground wet place to avoid stem corrosion.

7) When installing the valve, pay attention to its direction and installation position. Some valves are installed in a directional way, such as stop valve, plunger valve, throttle valve and check valve. Generally, there are arrows on the valve body of these valves, and the arrow direction represents the flow direction of the medium. If there is no mark on the valve body, the installation shall be carried out according to the principle of "low in and high out". Some valves have requirements on the installation position, such as the gravity lift check valve can be installed on the horizontal pipeline with the valve cover upward; the bottom valve can only be installed on the vertical pipe section of the water pump suction pipe, etc.

8) The valve shall be installed in a place convenient for operation and maintenance.