What is the difference between open stem gate valves and dark stem gate valves?

>1. The stem of the open rod gate valve is exposed and can be seen, while the stem of the dark rod gate valve is in the valve body and can not be seen;

2. The gate valve is driven by the thread between the stem and the steering wheel, so as to drive the gate up and down; The dark stem gate valve is driven up and down by turning the stem at a fixed point. The steering wheel and stem are connected to each other while switching on and off.

3. The drive thread of the dark rod gate valve is located in the body, in the process of opening and closing the valve, the stem is only rotating in situ, the naked eye can not judge the opening and closing state of the valve; But; The drive thread on the stem of the open stem gate valve is exposed to the outside of the valve body, so the opening and closing of the gate plate can be judged directly.

Dark rod gate valve

4. The height of the dark rod gate valve is small and the installation space is relatively small; The height of the gate valve is larger when it is fully opened, which requires a larger installation space;

5. The stem of the gate valve is outside the valve body, which is conducive to maintenance and lubrication; Dark stem gate valve stem thread inside the body, maintenance lubrication is difficult, and the stem is easy to be directly eroded by the medium, the valve is easy to be damaged. In the scope of use, the rod gate valve is more extensive.