What is a centerline butterfly valve?

What is a centerline butterfly valve?

Introduction of the centerline butterfly valve.

At present, the centerline butterfly valve as a component used to realize the pipeline system on-off and flow control has been extremely widely used in many fields such as petroleum, chemical industry, metallurgy, hydropower, and so on. In the known butterfly valve technology, its sealing form mostly uses a sealing structure, sealing material is rubber, PTFE, etc... Due to the limitations of structural features, it is not suitable for high-temperature resistance, high pressure and corrosion resistance, anti-wear, and other industries. A more advanced butterfly valve is a triple eccentric metal hard seal butterfly valve, the valve body and the valve seat for the conjoined components, seat sealing surface layer overlay welding temperature, and corrosion resistant alloy materials. The multi-layer soft stacked seal is fixed on the valve plate. Compared with the traditional butterfly valve, this butterfly valve has the advantages of high-temperature resistance, light operation, frictionless opening, and closing, and compensation sealing with the increase in torque of the transmission mechanism when closing, which improves the sealing performance and extends the service life of the butterfly valve.

 

Structural characteristics of the centerline butterfly valve.

The structural features of the centerline butterfly valve are the stem axis, butterfly plate center, and body center in the same position. The structure is simple and easy to manufacture. The common rubber-lined butterfly valve belongs to this category. The disadvantage is that the butterfly plate and the valve seat are always in the state of extrusion, scraping, large resistance distance, and fast wear. In order to overcome the extrusion, scraping, to ensure the sealing performance, the valve seat basically uses rubber or PTFE and other elastic materials, but also because the sealing materials in use temperature restrictions, which is why traditionally people think that the butterfly valve is not resistant to high-temperature reasons.

 

Features of the centerline butterfly valve.

1. Drive device flange

Can be used for the handle, gear operator, electric or pneumatic actuator.

2. Bushing

Reduces driving torque, supports the stem, and separates effectively from the valve body to reduce stem wear.

3. Disc shaft hole surface

Precise feet with the seat by polishing treatment.

4. High precision disc outer contour

Achieve airtightness requirements. Small start/stop torque and long seat life.

5. Valve stem seal

The valve stem is not easily deformed, eliminating the possibility of valve stem leakage.

6. Strong precision key

Provide possible attachments for manual lever or actuator.

7. Precision tapered pin

Ensures positive vibration resistance. Stem to disc connection. Easy field replacement.

8. One-piece stem design

High precision, good stability, and easy to start.

9. Side seal

No flange gasket is required.

10. Body-lined rubber seat

Good overall support, solid and firm, anti-stretch and anti-leakage.

11. O-ring

Prevent leakage at the shaft end.

 

Installation instructions for centerline butterfly valve.

Preparation work before installation.

1. Check whether the specification and material of the butterfly valve are in line with the design before installation.

2、And clean up the internal sand, dust, foreign matter, and debris before installation to avoid unpleasant action or leakage.

3、The relevant piping should be properly suspended and fixed according to the regulations before installation to avoid improper stress on the valve after installation.

4、The two flange surfaces of the piping must be aligned parallel and concentric.

5、No need to add a gasket between butterfly valve and flange during installation.

6、Where the butterfly valve is connected to the check valve or pump, use the expansion joint in the middle of the two so that the valve disc will not be obstructed by the twisting of the switch.

The valve disc will not be obstructed by twisting.

Installation steps.

1、Open the valve disc 10 degrees before installation. (The same before disassembly)

2、Set the auxiliary screw at the appropriate position to adjust the distance between the two flange surfaces.

3、Insert the butterfly valve without touching the two flange surfaces and put in the rest of the bolts.

4、After making sure that the center of butterfly valve is concentric with the center of the flange and the opening and closing position of the valve disc is not obstructed by the inner diameter of the flange or the adjacent machine, repeatedly lock the bolts in a diagonal and progressive manner until the flange surface touches the end of the valve body.

5、After the installation is completed, the full opening and full closing degree should be confirmed again.

Operation steps.

1、Before starting the operation, use air spray to clear the foreign matter on the pipeline and clean the inner surface of the pipeline with clean water.

2、Open the valve and check the angle indicator plate to avoid twisting more than the opening width and closing position.

3、The operation of the switch is completely based on the indicator, if other hand tools are used to apply force, the angle indicator plate and the switch will be damaged.

4、To do the piping pressure test, the valve should be opened.

5、After the piping, where it is in the full shutdown state for a long time, the switching action should be done 1~2 times a month to avoid the solidification condition.

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