How many kinds of fire valves are there?
Mar 23, 2021
Commonly used fire-fighting valves include gate valves, globe valves, throttle valves, instrument valves, plunger valves, ball valves, butterfly valves, check valves, remote floating ball valves, solenoid valves, pressure reducing valves, filters, wet alarm valves, etc. The working principle of common valves is introduced as follows:
Gate valve is one of the most common opening and closing valves, which use gates (that is, opening and closing parts, in which the opening and closing parts are called gates or gates, and the gate seat is called gate seat) to switch on (fully open) or Cut off (fully closed) the medium in the pipeline. It is not allowed to be used for shut-off, and it should be avoided to open the gate slightly during use, because the erosion of the high-speed flowing medium will accelerate the damage of the sealing surface. The Shuangde gate acts as a lifting motion on the side perpendicular to the center line of the gate seat channel, and cuts off the medium in the pipeline like a gate, so it is called a gate valve.
The types of gate valves can be divided into wedge gate valves and parallel gate valves according to the sealing surface configuration. Wedge gate valves can be further divided into: single gate type, double gate type and elastic gate type; parallel gate type gate valves can be Divided into single gate type and double gate type. Divided according to the thread position of the valve stem, it can be divided into two types: open stem gate valve and dark stem gate valve.
2.Globe valve
The opening and closing parts of the stop valve (GlobeValve) is a plug-shaped valve disc, the sealing surface is flat or conical, and the valve disc moves linearly along the center line of the valve seat. The movement form of the valve stem, (common name: dark rod), also has a lifting and rotating rod type, (common name: rising rod) a stop valve refers to a valve whose closing part (disc) 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. Since the opening or closing stroke of the valve stem of this type of valve is relatively short, and it has a very reliable cut-off function, and because the change of the valve seat port is in direct proportion to the stroke of the valve disc, it is very suitable for flow adjustment. Therefore, this type of shut-off valve is very suitable for shutting off or regulating and throttling.
3.Throttle valve
Throttle valve is a valve that controls fluid flow by changing the throttle section or throttle length. Connect the throttle valve and the one-way valve in parallel to form a one-way throttle valve. The throttle valve and the one-way throttle valve are simple flow control valves. In the hydraulic system of a fixed pump, the throttle valve and the overflow valve can be combined to form three throttle speed control systems, that is, the throttle speed control system of the oil inlet. System, oil return line throttling speed control system and bypass throttling speed control system. The throttle valve has no negative flow feedback function, and cannot compensate for the unstable speed caused by the load change. It is generally only used for occasions where the load change is not large or the speed stability is not high.
4.butterfly valve
Butterfly valve, also called flap valve, is a kind of regulating valve with simple structure. It can also be used for switching control of low-pressure pipeline medium. The butterfly valve in operation means that the closing part (disc or butterfly plate) is a disc and surrounds the valve. A kind of valve that the shaft rotates to achieve opening and closing, which mainly plays a role of cutting off and throttling on the pipeline. The butterfly valve opening and closing part is a disc-shaped butterfly plate, which rotates around its own axis in the valve body to achieve the purpose of opening and closing or adjustment.
5.ball valve
The opening and closing part (sphere) is driven by the valve stem and rotates around the axis of the valve stem. Utilization can also be used for fluid adjustment and control. Among them, the hard-sealed V-shaped ball valve has a strong shear force between its V-shaped core and the metal seat of the hard alloy. It is especially suitable for fibers and small solid particles. Materials and other media.
6.Pressure reducing valve
The pressure reducing valve is a valve that reduces the inlet pressure to a certain required outlet pressure through adjustment, and relies on the energy of the medium itself to automatically maintain a stable outlet pressure.
7.check valve
Check valve is also called one-way valve or check valve, its function is to prevent the medium in the pipeline from flowing back. The bottom valve of the pump to close the water also belongs to the non-return valve category. The valve that opens or closes on its own by the flow and force of the medium to prevent the medium from flowing back is called a check valve. Check valves belong to the category of automatic valves, which are mainly used in pipelines where the medium flows in one direction, and only allow the medium to flow in one direction to prevent accidents.
Check valve is a kind of automatic valve, its main function is to prevent the back flow of the medium, prevent the pump and drive motor from reversing, as well as the release of the container medium. Check valves can also be used to supply pipelines for auxiliary systems where the pressure may rise above the system pressure.
