The shut-off valve refers to a valve whose closing member moves along the center line of the valve seat. According to this movement form of the valve disc, the change of the valve seat port is proportional to the valve disc stroke. Due to manual
The opening or closing stroke of the valve stem of the shut-off valve is relatively short, and it has a very reliable cut-off function. And because the change of the valve seat port is proportional to the stroke of the valve disc, it is very suitable for
Adjustment of flow. Therefore, this type of shut-off valve is very suitable for use as a shut-off or adjustment and throttling.
Knowledge of Stop Valve selection
1. Stop valves should be used on pipelines or devices for high-temperature and high-pressure media. Such as thermal power plants, nuclear power plants, high-temperature and high-pressure pipelines of petrochemical systems.
2. On pipelines that do not require strict convection resistance. That is, where the pressure loss is not considered.
3. Small valves can choose needle valves, instrument valves, sampling valves, pressure gauge valves, etc.
4. There are flow adjustment or pressure adjustment, but the adjustment accuracy is not high, and the pipe diameter is relatively small.
5. Small fertilizers and large fertilizers in synthetic industrial production should use high-pressure manual angle stop valves with a nominal pressure of PN160 and a nominal pressure of 16MPa or PN320 and a nominal pressure of 32MPa.
6. In the desiliconization workshop of the alumina Bayer process and the pipeline that is prone to coking, it is easy to choose the manual direct-flow stop valve with separate valve body, removable valve seat, and cemented carbide seal pair.
7. In the water supply and heating projects in urban construction, the nominally small pipelines pass through, and manual stop valves, balance valves or plunger valves can be selected.
Stop Valve features
1. The structure is simpler than the gate valve, and it is more convenient to manufacture and maintain.
2. The sealing surface is not easy to wear and scratch, and the sealing performance is good. There is no relative sliding between the valve disc and the sealing surface of the valve body when opening and closing, so the wear and scratches are not serious, the sealing performance is good, and the service life is long.
3. When opening and closing, the disc stroke is small, so the height of the manual shut-off valve is smaller than that of the gate valve, but the structure length is longer than that of the gate valve.
4. The opening and closing moment is large, and the opening and closing is more laborious. The headmaster of the opening and closing time.
5. The fluid resistance is large, because the medium passage in the valve body is tortuous, the fluid resistance is large, and the power consumption is large.
6. When the nominal pressure of the medium flow direction is PN≤16MPa, the downstream flow is generally adopted, and the medium flows upward from below the valve flap; when the nominal pressure PN≥20MPa, the reverse flow is generally adopted, and the medium flows from the valve flap.
The direction is downstream. In order to increase the seal performance. When using the manual shut-off valve, the medium can only flow in one direction, and the flow direction cannot be changed.
