Working Principles and Characteristics of Triple Offset Butterfly Valve

Butterfly valves have been used in many industries today. Initially, the butterfly valve was only used to cut off and connect the water medium. The triple offset design enhances the function of the butterfly valve, and has become one of the valves with excellent performance in the industrial pipeline equipment. The triple offset butterfly valve, as the name suggests, is three independent offsets that are designed into the valve. In reality, many people can't tell which is the triple offset butterfly valve. So what are the working principles and characteristics of the triple offset butterfly valve?

Ⅰ. Working principles of the triple offset butterfly valve

In terms of the structure, the butterfly valve has a transverse valve port connected to the pipeline, the valve port has a valve plate, and the shaft is perpendicular to the valve port and passes through the valve body and the valve plate. The edge of the valve plate is provided with an outer spherical surface, and the valve port is provided with a sealing surface that can cooperate with the outer spherical surface. There is an eccentric distance b between the centerline, that is, the centerline of the valve port and the centerline of the rotating shaft, and there is an angle β between the connection line of the outer spherical surface and the centerline of the valve port, which is the principle of the triple eccentric butterfly valve.

This kind of water control valve cleverly places the triple eccentricity on the valve plate, and adopts a partial outer spherical structure on the outer edge of the valve plate. This structure needs to be completed on a CNC machine using a self-designed simple fixture. The outer eccentric spherical surface is polished to a roughness of Ra0.4, and the spherical surface is chrome-plated or surfacing with Stellite alloy, and the hardness reaches HRC45~60.

The eccentric angle is placed on the valve plate, and the valve seat is pressed on the valve body with a pressure ring, which solves the difficulties encountered in the processing of ordinary triple eccentric butterfly valves. A series of problems such as high cost, and all parts are modularized, warehouse management is simple, the processing is simple, maintenance is convenient, and spare parts costs are reduced.

Ⅱ. Characteristics of the triple offset butterfly valve

1. The triple offset butterfly valve is simple in structure and light in weight, and only consists of a few parts, which is easy to use.

2. After the valve plate is fully opened, the thickness of the butterfly plate is the only resistance for the medium to pass through the valve body, and the pressure is small, which can better control the flow.

3. When the valve plate is closed, the specific pressure between the outer spherical surface of the valve plate and the sealing surface of the valve seat is generated by the driving torque applied to the shaft. Coupled with the elastic compensation of the M-type elastic valve seat, the sealing performance of the valve can be enhanced, and the service life can be greatly improved.

The triple offset butterfly valve is suitable for making large-diameter valves. The triple offset butterfly valve can be widely used in the cutting of oil transportation pipelines, metallurgical steel plants, gas main pipeline regulation and cutting, chemical smelting equipment medium regulation and cutting, water treatment equipment inlet and outlet water regulation and cutting, thermoelectricity station cooling water system, natural gas, lye, seawater, acid and other industries.

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