A butterfly valve could be as tall as a small building: an extended stem can create a lot

Oct 19, 2023 | News

Butterfly valve, also known as flap valve, is a simple structure of the regulating valve, can be used for low-pressure pipeline media switching control of the butterfly valve is the closing member (valve flap or butterfly plate) for the disc, rotating around the valve axis to achieve the opening and closing of a kind of valve.

Butterfly valve is a kind of valve with disc-type opening and closing parts reciprocating about 90 ° to open, close or regulate the flow of media. Butterfly valve is not only simple structure, small size, light weight, material consumption, small installation size, driving torque is small, easy to operate, rapid, and can also have a good flow control function and close the sealing characteristics of the fastest-growing valve varieties in recent years.

Butterfly valve is mainly composed of valve body, valve stem, butterfly plate and sealing ring. The valve body is cylindrical, short axial length, built-in butterfly plate.

All of these components come in a wide selection of sizes and materials to suit different scenarios and different needs. For example, the length of the valve stem can be varied. We call butterfly valves with longer stem lengths than normal butterfly valves extension stem butterfly valves.

So what does the extension stem do? What kind of scenarios require an extension stem butterfly valve? Here we TWT,China will introduce it for customers.

extension stem butterfly valve manufacturer

Production aims of extension stem butterfly valves

Extending stem lengths are primarily intended for certain extreme environments, such as extremely high or low temperatures, or very deep underground missions. Let’s take the low temperature scenario as an example here.

(1) The long stem of the cryogenic valve has the function of protecting the stuffing box of the cryogenic valve, because the sealing of the stuffing box is one of the keys of the cryogenic valve. Leakage at the stuffing box will reduce the cooling effect and lead to liquefied gas gasification. In the low-temperature state as the temperature decreases, the packing elasticity gradually disappears, the leakage performance decreases, due to media leakage caused by packing and stem icing, affecting the normal operation of the valve stem at the same time also due to the stem up and down movement of the slurry filler scratches, resulting in serious leakage. Therefore, to ensure that the temperature of the packing environment part of 8 ℃ or more.

(2) low-temperature valve long stem cover structure to facilitate the winding of cold materials to prevent the loss of cold energy low-temperature valve.

(3) The long stem of the low-temperature valve facilitates quick replacement of the main part of the valve by removing the valve cover. Since the process piping and valves in the cold section of the equipment are often installed in the ‘cold box’, the long-necked valve cover can be extended through the ‘cold box’ wall. When replacing the main part of the valve, it is only necessary to dismantle it through the bonnet without dismantling the valve body. The valve body is welded to the pipework as an integral part, minimising leakage from the cold box and ensuring that the valve is airtight.

Advantages of extension stem butterfly valves

  1. Extended rod butterfly valve has a simple structure, small size, light weight, material consumption, small installation size, rapid switching, 90 ° reciprocating back and forth, driving torque is small, etc., used to cut off, connect, adjust the pipeline medium, with good fluid control characteristics and closing sealing performance.
  2. Extended rod butterfly valve can transport slurry, the least accumulation of liquid in the pipeline mouth. Under low pressure, it can achieve good sealing. Regulating performance is good.
  3. The streamline design of the butterfly plate makes the fluid resistance loss small, which can be regarded as an energy-saving product.
  4. Stem for the through-stem structure, after tempering treatment, has good overall mechanical properties and corrosion resistance, resistance to abrasion. Extended stem butterfly valve opening and closing the valve stem only for rotary movement without lifting operation, the packing of the valve stem is not easy to destroy, reliable sealing. Fixed with the butterfly plate taper pin, the outstretched end of the anti-punching type design, so as to avoid accidental breakage in the stem and butterfly plate connection when the stem collapsed out of the command.
  5. Connection methods include flange connection, butt-clamp connection, butt-welding connection and lug butt-clamp connection.

Application of extension stem butterfly valve

Extension stem butterfly valve is widely used in metallurgy, electric power, petrochemical, and water supply and drainage and municipal construction and other industrial pipelines, for regulating the flow rate and carry off the fluid use.As long as the medium temperature is suitable, the extension stem butterfly valve can work well in various scenarios.

Find your ideal extension stem butterfly valve from China

The sterm length of the extension sterm butterfly valve depends on the needs of the user and must be made of high quality and qualified raw materials, no matter how long the bar length is.

In TWT,China’s many years of experience we have always used high quality raw materials and offer a customised service.There is no need to hesitate to ask us what you need or to worry about the quality of our products.TWT is a leading manufacturer of valves in China.