Why is butterfly valve butterfly plate stainless steel magnetic?

It is normal for stainless steel to be magnetic.

There are several types of stainless steel. Other types except austenitic stainless steel are similar to steel in terms of magnetic philophilic properties;

Ferritic stainless steel is almost the same as magnetophilic steel;

Austenitic stainless steels are weakly magnetophilic, usually non-magnetic, and exhibit weak magnetism after machining.

If the valve is made of ferritic or duplex stainless steel, the mechanical and machinability properties of steel can be obtained. For applications such as butterfly valve discs that require high mechanical strength, ferritic or duplex stainless steels and non-austenitic stainless steels are more suitable.

Here are some of the 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, Su Yan, 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 structure of the valve plate resembles a butterfly, hence the name.

Because the opening and closing method of the butterfly valve wants butterfly wings.

Butterfly valve is used abroad, which translates to butterfly valve, referred to as butterfly valve.

The structure resembles a butterfly.

Due to the way the butterfly valve is driven, it moves like a butterfly. Tianjin Jinnan District Liangtai Valve Factory.

The sealing of the butterfly valve is mainly based on the combination of the butterfly plate of the butterfly valve and the sealing ring on the butterfly valve body. Generally speaking: butterfly valves are divided into soft seals and hard seals, soft seals are mainly made of EPDM, PTFE, NBR and other materials, and hard seals are metal.

The butterfly valve is switched at 90 degrees. After the full closing, the butterfly plate and the sealing ring are all combined. When opened, the butterfly plate is in a 90-degree direction with the valve seal.

Material issues. There is a problem with the structure of the butterfly valve itself. The temperature in the pipe, or the chemistry of the fiber medium, deforms the butterfly valve. The imitation butterfly plate could not be opened and closed normally, and the staff thought that the valve stem could not be rotated, and the handwheel was hard turned, resulting in the butterfly plate being broken.

The rubber-lined butterfly valve is lined with PTFE with a spherical sealing surface.

Rubber-lined butterfly valves. Butterfly plate, the valve is light to operate, tight sealing performance, long service life; It can be used for quick cut-off or flow adjustment. Ideal for applications that require reliable sealing and good regulation characteristics. The valve body adopts a split type, and the sealing at both ends of the valve shaft is controlled by the rotating base surface fluororubber between the butterfly plate and the valve seat; Ensure that the valve shaft is not in contact with the fluid medium in the cavity.

It is widely used in the transportation of liquids and gases (including steam) in various types of industrial pipelines, and the use of seriously corrosive media, such as: sulfuric acid, hydrofluoric acid, phosphoric acid, chlorine, strong alkali, aqua regia and other highly corrosive media.

The butterfly valve is a type of valve, but the so-called valve disc, which I understand, may refer to the spool inside the butterfly valve, that is, the disc plate.

Disc valve (also known as butterfly valve) English name: butterfly valve, and valve butterfly one meaning.

It's not the same, although the position is changed, one is the valve and the other is the small fittings inside.

28, the owner of Furong Mountain in the snow Liu Changqing is far away in the twilight, and the white house is poor in the cold weather.

Removing the plate is a painful thing.

Method 1: Take out the pin, and drill the pin out if you can't get it out (tragedy) Method 2: The pin is too big, drill a screw hole in the pin, then put on the screw, and pull out the pin (can't afford to hurt) Summary: If it is repaired, it is recommended that the buyer replace it with a new one.

Of course, if the pin is easy to remove, that's a different story.

1. Midline butterfly valve (concentric butterfly valve).

The structural characteristics of the centerline butterfly valve are that the stem axis, the center of the butterfly plate, and the center of the body are in the same position. The structure is simple and easy to manufacture. The common rubber-lined butterfly valve falls into this category.

The disadvantage is that the butterfly plate and the valve seat are always in a state of extrusion and scraping, the blocking distance is large, and the wear is fast. In order to overcome extrusion, scratching, and ensure sealing performance, the valve seat is basically made of elastic materials such as rubber or PTFE, but because the sealing material is limited by temperature in use, this is why it is traditionally believed that butterfly valves are not resistant to cavity bright high temperatures.

2. Single eccentric butterfly valve.

The structural characteristics of the single eccentric butterfly valve are that the stem axis deviates from the center of the butterfly plate, so that the upper and lower ends of the butterfly plate no longer become the rotary axis, disperses, reduces the excessive extrusion of the upper and lower ends of the butterfly plate and the valve seat, and solves the extrusion problem of the butterfly plate and the valve seat of the concentric butterfly valve. However, due to the single eccentric structure, the scratching phenomenon between the butterfly plate and the valve seat has not disappeared during the whole opening and closing process of the valve, and it is similar to the concentric butterfly valve in the application range, so it is not used much.

3. Double eccentric butterfly valve.

The double eccentric butterfly valve is further improved on the basis of the single eccentric butterfly valve, and it is also the most widely used. Its structure is characterized by a deviation from both the center of the butterfly plate and the center of the body at the stem axis. The effect of double eccentricity makes the butterfly plate quickly detach from the valve seat after the valve is opened, which greatly eliminates the unnecessary excessive extrusion and scratching phenomenon between the butterfly plate and the valve seat, reduces the opening resistance, reduces wear and tear, and improves the life of the valve seat.

The significant reduction of scratching also makes the double eccentric butterfly valve also use metal seats, which improves the application of butterfly valves in high-temperature fields. However, because its sealing principle is a positional sealing structure, that is, the sealing surface of the butterfly plate and the valve seat is in line contact, and the elastic deformation caused by the extrusion of the valve seat by the butterfly plate produces a sealing effect, so the closing position is very high (especially the metal valve seat) and the pressure bearing capacity is low, which is why people traditionally believe that the butterfly valve is not resistant to high pressure and has a large leakage.

Fourth, three eccentric butterfly valves.

To withstand high temperatures, hard seals must be used, but the leakage is large; To achieve zero leakage, it is necessary to use a soft seal that is not resistant to high temperatures. In order to overcome the contradiction of double eccentric butterfly trace valve removal, the butterfly valve was partially dismantled for the third time. Its structural characteristics are that at the same time as the axial position of the valve stem of the double eccentricity is eccentric, the conical axis of the sealing surface of the butterfly plate is deviated from the cylindrical axis of the body, that is to say, after the third eccentricity, the sealing section of the butterfly plate is no longer a true circle, but an ellipse, and the shape of the sealing surface is also asymmetrical, one side is inclined to the center line of the body, and the other side is parallel to the center line of the body.

The biggest feature of this third eccentricity is that it fundamentally changes the sealing structure, no longer a position seal, but a torsion seal, that is, it does not rely on the elastic deformation of the valve seat, but completely relies on the contact surface pressure of the valve seat to achieve the sealing effect, so it solves the problem of zero leakage of the metal valve seat in one fell swoop, and because the contact surface pressure is proportional to the medium pressure, the high pressure and high temperature resistance is also easily solved.

Dismantling the plate is a more painful thing Method 1: Take out the pin, and drill the pin off if you can't get it out (tragedy) Method 2: The pin is too big, just drill a screw hole in the pin, and then put on the screw, pull out the pin (can't hurt) Summary:

If it is repaired, it is recommended that the buyer replace it with a new one, of course, if the pin is easy to take out, it is another matter.