What are the commonly used valves in power plants, and what are the commonly used valves in thermal

Cut off the media in the line.

Check valve, also known as check valve or check valve, check valve is an automatic valve, its function is to prevent the reverse flow of the medium in the pipeline, to prevent the pump and drive motor from reversing, and the leakage of container medium. The foot valve of the suction off of the water pump also belongs to the category of check valves.

Explosion-proof valves, accident valves, etc., the function of safety valves is to prevent the medium pressure in the pipeline or device from exceeding the specified value, so as to achieve the purpose of safety protection.

Regulating valves, throttle valves and pressure reducing valves, their functions are to regulate the pressure, flow and other parameters of the medium.

2) Vacuum: true.

Here are some well-known brands recognized in the valve industry, which are widely recognized and have a high reputation. While rankings may vary depending on time and market conditions, the following brands are generally considered to be among the top brands in the valve industry:

The following influential first-line brands of water system valves and industrial valves can be used as a reference, but for reference only: Suzhou Neway Valve, Shanghai Guanlong Valve, Shanghai Qizhong Valve, Sanhua, Chaoda, Shentong, Su Valve, Nanfang, Jiang.

First, the word Yao. The above manufacturers are only estimates and references, and the specific situation may vary or fluctuate at any time due to changes in a series of factors such as changes in the market, the size of the competition pattern, and the stability of product quality. As an indispensable key device in industrial production and civil facilities, the quality and reputation of the valve brand directly affect the satisfaction and trust of users.

These brands are known in the valve industry for their innovative technology, high-quality products and reliability. It is important to note that the market and industry are evolving rapidly, and different rankings may vary depending on time and region. For the most up-to-date ranking information, it is recommended to refer to industry reports, professional organizations or market research data for more detailed and accurate information.

The unit of the manual valve is the liquid dry song - the defeat grip - the unit.

The troubled unit of worm gear electric pneumatic hydraulic valve is - set.

Hydropower station main valve.

The main valve, which is present in every hydrogenerator, is installed at the junction of the pressure pipe and the volute.

Master valve, a pressure pipe to install multiple generators or special requirements.

The role of the main valve of the water turbine.

The main valve of the turbine is installed between the pressure pipeline and the volute, and the main valve only has two working positions: fully open and fully closed, and does not adjust the inlet flow rate of the turbine, and its functions include the following aspects.

1. Provide safe working conditions for unit maintenance. When the power station adopts a joint or grouped water supply mode in which a pressure pipeline supplies water to two or more units, one of the units can be overhauled and its main valve can be closed, so as to form a safe working condition without affecting the operation of other units.

2. Reduce the water leakage of the unit when it is shut down, and shorten the time required for starting when it is turned on. The water guide mechanism of the turbine is often not closed tightly, and there is a large amount of water leakage after the shutdown. This not only wastes water energy, but also causes cavitation damage in the crevices due to water leakage.

According to statistics, the general guide vane leakage is about 2%-5% of the maximum flow rate of the turbine, and the serious can reach 8%, and the small unit with a high water head can not even stop due to excessive water leakage. When the unit is shut down for an extended period of time, closing its inlet valve can greatly reduce water leakage. When the unit is shut down for a short time, the pressure pipeline inlet gate is generally not closed.

Because this will release the water in the pressure pipe due to the leakage at the end of the pipe, and the pressure pipe needs to be filled with water again before starting again, which not only prolongs the starting time of the unit, but also makes the unit unable to maintain the standby state at any time, and loses the flexibility and quickness of the operation of the hydropower station. Closing the inlet valve reduces both leakage and the time it takes to start the unit again. For medium and high head power stations with long pressure pipes, this role of the main valve of the turbine is more obvious.

3. Prevent the expansion of the crew flight accident. When the unit or speed control system fails, the turbine can not be shut down in time may cause the crew to escape the accident, at this time, the speed signal should automatically issue an instruction to close the main valve of the turbine urgently, quickly cut off the water flow, prevent the unit from flying, and avoid the expansion of the accident. If the main valve of the turbine is not set, the inlet gate of the pressure pipe should be closed quickly, but because it takes time for the pressure pipe to empty, the unit will take a long time to escape.

In thermal power plants, the main types of valves used for operation with valve electric devices are gate valves, globe valves, butterfly valves and ball valves.

The opening and closing parts of the gate valve are gate shaped, and the gate moves in a straight line along the direction perpendicular to the flow of fluid, cutting off or opening the channel of fluid flow, and it is the main valve used in large-diameter pipelines (dg greater than 100mm) in thermal power plants.

The function of the gate valve is to open or close the pipe passage by moving the disc along the vertical line of the center of the passage. The main opening and closing parts of a gate valve are the disc and seat. The structure of a gate valve is mainly composed of valves, bonnets, brackets, stems, seats, rams and other parts.

According to the structure and shape of the disc, gate valves can be divided into two categories: wedge gate valves and parallel gate valves.

According to the different movement of the valve stem when the gate valve is opened and closed, the gate valve can be divided into two categories: open rod type and dark rod type.

The characteristics and uses of the gate valve: the advantages of the gate valve are that the flow resistance is small, the opening and closing is more labor-saving, not limited by the flow direction of the medium, the medium can flow in two directions, the structure size is small, and the sealing surface is less eroded by the medium when it is fully opened. The disadvantages are that the structure is complex, the height size is large, the opening requires a certain space, the opening and closing time is long, and the sealing surface is easy to be eroded and abrased when opening and closing.

The application range of gate valve is determined by its characteristics, and it is generally used for shut-off of pipelines with a nominal diameter greater than 100mm.