The most shocking movie in this summer season is definitely The Bravest. Before the performance of the movie, it was noticed by many people. The film was adapted from real events so that ordinary viewers could get to know more about firefighters. The movie tells us to close a valve that 8000 turns are required. It takes 6 hours to close the valve manually. It;s just a valve. What kind of valve needs to turn so many turns?
Valves are certainly not unfamiliar to everyone. Faucets at home and floating balls controlling toilet outflow are all one kind of valves. Valves are used to open and close pipelines, control flow direction, regulate and control the data of fluid transported, such as temperature, pressure and flow of pipeline accessories, with cut-off, regulation, diversion, countercurrent prevention, stable pressure. Functions such as diversion or overflow pressure relief.
In the data of the valve, the pressure can be withstood is expressed by MPa or PN, and the size of the valve is expressed by DN. The unit is MM. For example, DN20 represents the valve with a standard diameter of 20MM.
The outside diameter of the valve ranges from a very small instrument valve to an industrial pipeline valve with a diameter of several meters. The working pressure of the valve ranges from 0.0013 MPa to 1000 MPa under ultra-high pressure. The working temperature ranges from -270 to 1430 under different conditions and pressures, the valve can control the flow of various types of fluids such as water, oil and gas. Move,
Valves are produced with the emergence of fluid pipelines, and also with the development of fluid pipeline materials.
The earliest valves have a history of thousands of years. In ancient China, when bamboo was used to absorb brine to make salt, wooden plug valves were used. Later, ancient Egyptians and Greeks invented several original wooden valves, mainly for irrigation crops and water conservancy construction. The function of the original valves was to prevent the backflow of water and control the distribution of water flow.
With the development of industry, smelting technology has brought valves into metal products. Various metal valves and alloy valves have been invented, and the types and applications of valves are increasing.
Valves are the control parts of pipeline fluid delivery system, which are used to change the channel section and the direction of medium flow. Valves range from the simplest globe valve to various valves used in extremely complex automatic control systems. They have a wide variety of varieties and specifications. According to their functions, they can be divided into fixed ball valves, globe valves, gate valves and swing check valves. Butterfly valves, etc.
Fixed ball valve, through the sphere in the rotary valve to control the opening and closing of the valve, there is a through hole in the middle of the sphere, which can rotate 90 degrees. The diameter of the through hole is equal to or less than the diameter of the pipeline. When the sphere rotates 90 degrees, the inlet and outlet surfaces of the pipeline are spherical, thus closing the valve and cutting off the fluid. When the spherical valve rotates 90 degrees, The inlet and outlet surfaces of pipelines are spherical orifices, and the fluid can rotate to different angles through valves, thus controlling the size of the fluid. Fixed ball valves are often used in general pipelines, such as water, oil, steam, etc.
Globe valves, also known as shutoff valves, can completely seal off the outlet of the valve seat by applying pressure through the rotating stem, thus preventing the flow of fluid. Globe valves are commonly used in corrosive gases such as natural gas, liquefied gas, sulfuric acid, and liquid pipelines.
Gate valves, like a gate, control the fluid by rotating the stem and controlling the vertical movement of the gate. The sealing rings on both sides of the gate can completely seal the whole section. Gate valves can only be fully opened and closed, and can not be used as valves to regulate flow. Gate valves are mainly used in pipes such as tap water, sewage and ships. Used for closure device.
Swing check valve is a kind of automatic valve, which opens the valve cover by the pressure of the fluid. When the pressure of the fluid in the valve inlet and outlet pipeline is balanced, the valve cover can close by its own gravity to prevent the fluid from passing through. Its main function is to prevent the fluid from backflow, which belongs to the automatic valve class. It is mainly used in petroleum, chemical, pharmaceutical and other pipelines.
Butterfly valve, also known as flip valve, can rotate 90 degrees, drive the disc to rotate through the rotating stem, change the angle of the disc plate can control the flow of fluid, can be used to cut off, connect, regulate the fluid in the pipeline; often used in water supply, gas supply and other pipelines, as a regulating and closing device.
Regulating valve, also known as control valve, is used to control the size of the fluid. When the regulating part of the valve receives the regulating signal, the valve stem will automatically control the switching degree of the valve according to the signal, so as to achieve the regulation of the flow rate and pressure of the fluid. It is often used in heating, gas, petrochemical and other pipelines.
In the movie, the valve that needs to turn 8000 turns to close should be a gate valve. In reality, some of these valves need to turn tens of thousands of turns to close, so they are usually driven by motors. Many people do not understand why they have to turn so many turns.
That;s because the pressure in the pipeline is amazing. There are 100,000 tons of oil in the film. You can imagine the pressure in the pipeline installed under the tank. To close the valve on the pipeline is equivalent to counteracting the pressure in the whole tank. So you need to use the lever principle. The more turns you turn, the more you need. The less powerful it is.
For example, there are 100 buckles on the valve (the professional name is pitch). If the gate is to drop about 1 meter, it needs 80 turns to drop one buckle, so that the force needed for a turn will be much smaller. Of course, the valve is usually driven by a motor, thousands of turns per minute, and closing the valve will take a few minutes. So when a fire breaks out, it must be power off. It;s no exaggeration that it takes several hours to turn manually. Don;t think that 8000 turns in the movie is a lot. In reality, tens of thousands of turns are normal. You can imagine how difficult it is for firefighters in this situation.
With the development of valve technology and application fields, the valve family will continue to grow, safer, reliable and efficient flow control system will continue to appear in all walks of life.