Open lever gate valve and dark lever gate valve

Open stem gate valve and dark stem gate valve difference

1. The screw can not be seen in the dark rod valve, but the screw can be seen in the open rod. This is an easy place to identify;

2 dark rod valve in the switch when the steering wheel and the valve stem is connected together, so in fact, relatively stationary, what is relatively stationary, I want to learn physics friends should know it. Dark rod valve is through the stem rotation at the fixed point to drive the disc up and down the gate to complete the start and close action; Open stem valves lift and lower the disc by threaded rotation of the stem and steering wheel. This can also easily distinguish the difference between dark rod and open rod gate valve;

3. The prompt screw of the dark rod gate valve is only rotating, and it does not move up and down. What is exposed is only a rod, whose nut is also fixed on the gate, and the gate is lifted by rotating the screw. And open rod gate valve is different, open rod gate valve lifting screw is exposed, nut allowance hand wheel, and is fixed, by rotating the screw to lift the gate, screw and gate only relative rotation motion, there is no relative axial rotation, and the appearance of a door bracket.