Butterfly valve is also known as the flap valve, is a simple structure of the control valve, can be used for the low pressure pipeline medium switch control of butterfly valve is to close pieces (disc or disc) for the disc, rotating around the valve shaft to open and close a valve.
Valves can be used to control the flow of various types of fluids such as air, water, steam, corrosive media, mud, oil, liquid metal and radioactive media.It is mainly used for cutting and throttling in pipelines.Butterfly valve opening and closing parts is a disc shaped disc, in the valve body around its own axis rotation, so as to achieve the purpose of opening and closing or regulation.
Butterfly valve structure
It is mainly composed of valve body, stem, butterfly plate and sealing ring.The valve body is cylindrical, short axial length, built-in butterfly plate.
Butterfly valve characteristics
1. Butterfly valve features simple structure, small volume, light weight, low material consumption, small installation size, quick switch, 90° reciprocating rotation, small driving torque, etc. It is used to block, turn on and adjust the medium in pipeline, with good fluid control characteristics and sealing performance.
2, butterfly valve can transport mud, at the mouth of the pipe liquid minimum.Good sealing can be achieved under low pressure.Good adjustment performance.
3, the streamlined design of butterfly plate, so that the fluid resistance loss is small, may be said to be an energy-saving product.
4, the valve stem for the through rod structure, after conditioning treatment, has a good comprehensive mechanical properties and corrosion resistance, abrasion resistance.Butterfly valve open and close when the stem only rotary motion and not for lifting operation, stem packing is not easy to destroy, sealing reliable.It is fixed with the disc tapered pin, and the overhanging end is designed to prevent the disc stem from crashing when it breaks unexpectedly at the connection between the disc stem and the disc.
5. Connection methods include flange connection, clamping connection, welding connection and lug clamping connection.
The driving forms include manual, worm drive, electric, pneumatic, hydraulic, electro-hydraulic linkage and other actuators, which can realize remote control and automatic operation.
1. Easy and quick opening and closing, labor-saving, small fluid resistance, can be often operated.
2. Simple structure, small external size, short structure length, small volume, light weight, suitable for large diameter valves.
3, can transport mud, at the pipe mouth of the liquid storage minimum.
4. Good sealing can be achieved under low pressure.
5. Good adjustment performance.
6. When the valve seat channel is fully open, the effective flow area is large and the fluid resistance is small.
7, the opening and closing moment is small, because the rotary shaft on both sides of the butterfly plate by the medium action is basically equal, and the direction of the torque is opposite, so the opening and closing is less effort.
8, sealing surface materials are generally rubber, plastic, so the low-pressure sealing performance is good.
9. Easy installation.
10. Flexible and labor-saving operation, manual, electric, pneumatic and hydraulic modes can be selected.
Now, due to the development of science and technology and the progress of material science, the material of manufacturing butterfly valve is more and more diverse.And the user in the choice of butterfly valve, often material is a very important consideration of the index.So, in the case of not relying on the manufacturer's instructions, how should the user identify the material of the butterfly valve?
Material identification method of butterfly valve
1. Chemical and spectral analysis
Chemical analysis has long been used to determine the content of various elements in butterfly valve materials, and this method can be said to be very reliable according to the long use.Spectral analysis refers to the material of butterfly valve under the excitation of high temperature and high energy emission spectrum, so the use of spectral analysis can also determine the material of butterfly valve.
2. Spark identification
When a metal material is polished, it often sparks from intense friction.The identification of butterfly valve material is based on this method, to its grinding, by identifying its spark characteristics to identify the composition of the material.
3. The cross section
By cutting the butterfly valve sample, the content of various elements in the valve material can be distinguished from the color, grain and other characteristics of its section, but this method often needs to have a certain metal material manufacturing experience to achieve.
1. Small range of operating pressure and operating temperature.
2. Poor sealing.
Butterfly valve according to the structure can be divided into offset plate, vertical plate, inclined plate and lever.
According to seal form can be soft seal type and hard seal type two kinds.The soft sealing type generally USES the rubber ring seal, the hard sealing type usually USES the metal ring seal.
According to the type of connection can be divided into flange connection and sandwiching connection;According to the transmission mode can be divided into manual, gear drive, pneumatic, hydraulic and electric.