Basic Structure, Working Principle and Precautions of Globe Valve

 

The globe valve is a valve that uses the valve stem to lift and drive the valve head, thereby changing the distance between the valve disc and the valve seat to achieve opening and closing control. The globe valve is the most widely used cut-off valve in chemical production. Globe valves are mainly used for the control of water, steam, compressed air and other pipelines in actual production, but they are not suitable for materials with high viscosity and easy crystallization.

The structure of the globe valve is relatively simple, but the actual operation is simple and labor-saving, and it has a good performance in regulating the flow and cutting off the channel. The opening and closing speed is slow and there is little water hammer. The globe valve is compact in structure and has obvious characteristics in appearance. The top of the valve is equipped with a hand wheel and a valve stem, and the middle is provided with a thread and a stuffing box sealing section.

The main way to judge the opening and closing state of the globe valve when it is in use is to observe the exposed height of the valve stem to control the operation of the valve. There may be a gap between the valve stem and the valve cover, which is prone to medium leakage, which can be solved by packing seal. The stem thread of the small globe valve is set in the valve body, so it is more likely to be in contact with the medium for a long time during use, and it is easy to be corroded by the medium.

Advantage

1. The structure is simple, and the manufacture and maintenance are relatively convenient.

2. The working stroke is small and the opening and closing time is short.

3. Good sealing performance, small friction between sealing surfaces, and long service life.

Precautions

1. The globe valve should be checked for leakage before opening to determine whether the valve has no leakage defects and whether the stuffing box has no leakage defects.

2. If the valve stem operation of the globe valve cannot be completed by hand, do not use an extension wrench to force the opening and closing to avoid damage to the valve or even a safety accident.

3. When the globe valve is applied to the medium-pressure steam pipeline, the condensed water needs to be removed before opening, and then the steam preheats the pipeline, and the preheating pressure is kept between 0.2 and 0.3 MPA. The purpose of this is to avoid damage to the seals caused by sudden changes in temperature and pressure, and the pressure can be adjusted to the required level after confirming that the state is stable.

4. The installation of the globe valve should refer to the direction of the fluid, and pay attention to keep the pipeline fluid consistent with the valve marking arrow. More products from www.dvsvalve.com.