High Performance Comes From Improvement: Double Offset High Performance Butterfly Valves

Oct 13, 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 refers to the closing member (valve flap or butterfly plate) for the disk, rotating around the valve axis to achieve the opening and closing of a valve.

Offset butterfly valve means that the valve is installed in a vertical position in the pipeline. Its structure is simple, small size, light weight, good sealing,therefore, the offset butterfly valve is light and flexible in operation, easy to realize rapid opening, closing and shutting, and easy to maintain.

Double offset butterfly valve is a kind of improved offset butterfly valve, its structural characteristics are that the axis of the valve stem deviates from the center of the butterfly plate as well as the center of the body. The effect of double offset makes the valve to be opened after the butterfly plate can be quickly detached from the valve seat, greatly eliminating the butterfly plate and the seat of the unnecessary excessive extrusion, scraping phenomenon, which guarantees them higher performance. Therefore, it is called double offset high performance butterfly valve in the industry.

Today we will talk about this improved high performance butterfly valve in detail.

Structure Of Double Offset Butterfly Valves

The so-called double offset, the first offset refers to the valve stem shaft off the center of the sealing surface, that is, the valve stem shaft behind the butterfly plate surface. This offset makes the contact surface of butterfly plate and valve seat are sealing surface, which fundamentally overcomes the inherent shortcomings of centerline butterfly valve, thus eliminating the possibility of internal leakage at the upper and lower intersections between the stem shaft and sealing valve seat.

Another offset refers to the center of the valve body overwater hole and stem axis left and right offset, that is, the stem axis will be separated into two parts of the butterfly plate on one side and one side less. This offset can make the butterfly plate in the opening and closing process can be quickly detached from or close to the valve seat, reduce the friction between the butterfly plate and the sealing seat travel, reduce wear and tear, reduce the opening and closing torque, prolong the service life of the valve seat.

Structural Features Of Double Offset Butterfly Valve

1 Reasonable design, compact structure, easy to install and disassemble, easy to maintain.

2 offset structure reduces the friction of sealing ring and prolongs the service life of the valve.

3 Completely sealed, zero leakage. Can be used in ultra-high vacuum conditions

4 Replacement of the valve plate sealing ring, butterfly plate, shaft and other materials, can be applied to a variety of media and different temperatures.

Application of Double Offset Butterfly Valve

Double offset Butterfly Valve is also called high performance butterfly valve, which is mainly used in water plant, power plant, steel smelting, chemical industry, water source engineering, environmental facilities construction and other systems for drainage, especially for waterway pipeline, as a regulating and intercepting equipment. Compared with the center line butterfly valve, double offset butterfly valve is more resistant to high pressure, longer life, good stability. Compared with other valves, the larger the caliber, the lighter the material, the lower the cost. However, due to the butterfly plate in the center, the flow resistance is large, so less than DN200 butterfly valve is not very meaningful.

Selection of Double Offset Butterfly Valve

The application field of double offset butterfly valve is  related to the sealing materials used in different butterfly valves. Double offset butterfly valve usually adopts tetrafluoroethylene material to do its sealing seat, and metal sealing seat can also be used to expand its application in the field of high temperature.

However, the sealing of double offset butterfly valve with metal sealing seat still belongs to the positional sealing structure, i.e., the sealing surface of the butterfly plate and the valve seat is in line contact, so it is not able to withstand high pressure, which will inevitably lead to a larger amount of leakage when it is applied in the high pressure system.

Therefore, in the high-pressure or the system that requires the cut-off to be tight, the selection of double offset butterfly valve with metal sealing seat should be avoided as much as possible.

Where to Find Double Offset High Performance Butterfly Valve

It can be said that the manufacture of double offset high performance  butterfly valves is a highly specialized job, and the selection of double offset high performance butterfly valves also requires the addition of specialized knowledge. So we more suggest buyers to look for a professional, experienced and enthusiastic manufacturer as we TWT Valve Co., Ltd from Tianjin,China.

With professional staff, qualified quality control and good service, TWT Valve Co., Ltd from Tianjin,China is the leading manufacturer in China. Choose us, give us a chance and give you a satisfactory order.