Butterfly valves and gate valves in different conditions of application

Butterfly valves and gate valves in different conditions of application.

Butterfly valves and gate valves are used in pipelines to switch and regulate the flow. Of course, in the butterfly valve and gate valve selection process or method.

To reduce the depth of pipeline overburden in the water supply network, larger pipelines generally use butterfly valves as they are less affected by overburden depth. However, gate valves are preferred but come at a higher price. The selection of valve type should be based on specific circumstances. Over the past decade, butterfly valves have shown higher failure rates compared to gate valves, so expanding the use of gate valves is worth considering.

In recent years, many domestic valve manufacturers have developed and imitated soft-seal gate valves on the gate valve. This gate valve has the following characteristics compared to traditional wedge-type or parallel double gate type gate valves:

Soft sealing gate valve body, valve cover are cast using precision casting method, achieving one-time molding, with no basic mechanical processing, without the use of sealing copper ring, saving non-ferrous metals.

Soft seal gate valve bottom without pits, no accumulation of slag, gate valve opening and closing of the failure rate is low.

Soft seal rubber lined valve plate size unity, interchangeability.

Therefore, the soft seal gate valve is widely used in the water supply industry. Currently, domestic manufacturers can produce soft seal gate valves with a diameter of up to 1500mm, but most manufacturers focus on sizes between 80-300mm. There are still many manufacturing process challenges in the domestic industry. The key component of the soft sealing gate valve is the rubber-lined valve plate, which has high technical requirements. Not all overseas manufacturers can meet these requirements, so they are often sourced from reliable factories for assembly.

The domestic soft seal gate valve has a copper nut block embedded in the rubber lining valve plate above, similar to the structure of the gate valve. However, due to friction, the activities of the nut block can easily cause the lining of the valve plate to peel off. In contrast, a foreign company's soft seal gate valve has the copper nut block embedded in the rubber-lined gate, forming a whole to overcome the above shortcomings. However, the valve cover and valve body combination have higher concentricity requirements.

However, when opening and closing the soft seal gate valve, it should not be closed too tightly. As long as the water flow can be achieved, otherwise it may be difficult to open or cause the rubber lining to peel off. In the pressure test of the valve, a torque plate hand is used to control the degree of closure. Valve operators in the water company should follow this method of opening and closing.

Butterfly valve is different from gate valves in its usage.

The gate valve has low flow resistance and good sealing performance. However, if the valve plate switch is not in place, the media can cause damage to the gate valve seal.

Butterfly valve, also known as the flap valve, is a simple structure of the regulating valve, can be used for low-pressure pipeline media switching control of the butterfly valve refers to 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, the valve can be used to control the flow of various types of fluids, such as air, water, steam, a variety of corrosive mediums, slurries, oils, liquid metals and radioactive media. Mainly in the pipeline to cut off and throttling effect. Butterfly valve opening and closing parts is a disc-shaped butterfly plate, in the valve body around its own axis rotation, so as to achieve the purpose of opening and closing or regulation.

Butterfly driven by the valve stem, if turned 90°, will be able to complete an opening and closing. Change the deflection angle of the butterfly plate, you can control the flow of the medium.

Butterfly valve is suitable for transporting a variety of corrosive and non-corrosive fluid media pipelines in furnace, gas, natural gas, liquefied petroleum gas, city gas, hot and cold air, chemical smelting, power generation, environmental protection, building water supply and drainage, and other engineering systems to regulate and cut off the flow of media.

Gate valve (gate valve) is an opening and closing member of the gate, the movement direction of the gate is perpendicular to the direction of the fluid, the gate valve can only be used for the full open and full closed, does not apply to the parameters of the gate, usually 5 °, the media temperature is not high for the 2 ° 52'. Improve its craftsmanship, make up for the angle of the sealing surface in the processing of the deviation, this gate is called resilient gate.

Gate valve closed, the sealing surface can only rely on media pressure to seal, that is, only rely on media pressure to the sealing surface of the gate to the other side of the valve seat to ensure that the sealing surface sealing, this is the self-sealing. Most of the gate valve is used to force sealing, that is, when the valve is closed, to rely on external forces to force the gate to the valve seat to ensure that the sealing surface of the sealing.

Motion: The gate of the gate valve with the valve stem for linear motion, also known as open stem gate valve. Usually there are trapezoidal threads on the lifting rod, through the nut at the top of the valve and the guide groove on the valve body, the rotary motion into a straight line motion, that is, the operating torque into the operating thrust. When the valve is opened, the passage of the fluid is completely free when the height of the gate lift is equal to 1:1 times the diameter of the valve, but this position cannot be monitored during operation. In actual use, it is the apex of the valve stem as a mark, i.e., the position of opening motionless, as its fully open position. In order to take into account the temperature changes in the phenomenon of locking, usually open to the apex of the position, and then back 1/2-1 turn, as the fully open position of the valve. Therefore, the valve's fully open position, according to the position of the gate (i.e., trip〉 to determine. Some gate valve stem nut is located in the gate, the handwheel rotation drives the valve stem rotation, so that the gate lift, this valve is called a rotating rod gate valve or called the dark rod gate valve.