Assembly of Butterfly Valve Components and applying GDT to Assembly Using NX CAD

Objective -To assemble the different component of Butterfly Valve and applying GDT rules using NX CAD

Assembly Of Butterfly Valve : -

GDT - Assembly

Detailed Report of each component Types and Application of Butterfly Valve

Introduction

A butterfly valve is a quarter-turn valve that initiates throttling and flows control of fluids. Given its name, you can easily visualize a thin metal disc that “flutters” about a fixed axis (stem assembly). The opening and closing mechanism allows and restrict the flow of a medium between an upstream and downstream pipe.. A 90° rotation of the handle provides a complete closure or opening of the valve. Large Butterfly valves are usually equipped with a so-called gearbox, where the handwheel by gears is connected to the stem. This simplifies the operation of the valve, but at the expense of speed.

The assembly of Butterfly Valve consist of Following components : -

1. Body

2. Disc

3. Retainer

4. Lever handle

5. Shaft

6. Nut

7. Bolt

Description of Different Component of Butterfly Valve:

1. Body: - Butterfly Valve has one of the major components that is a body that is fit between two pipe flanges.The following sets of the command used for Body designing in NX CAd

a. Sketching

b. Extrdung

c. Counterboring

2. Disc Plate:- Two methods are used to secure the disk to the stem so that the disk rotates as the stem is turned. In the first method, the disk is bored through and secured to the stem with bolts or pins. The alternate method involves boring the disk as before, then shaping the upper stem bore to fit a squared or hex-shaped stem. This method allows the disk to "float" and seek its center in the seat. Uniform sealing is accomplished and external stem fasteners are eliminated. This method of assembly is advantageous in the case of covered disks and in corrosive applications.

3. Shaft /Stem: -In order for the disk to be held in the proper position, the stem must extend beyond the bottom of the disk and fit into a bushing in the bottom of the valve body. One or two similar bushings are along the upper portion of the stem as well.

4. Retainer: - Butterfly valves comprise a valve seat comprising a generally S-shaped cross-section and a valve seat retainer configured with appropriately shaped cooperating surfaces.

• Soft Seated (PTFE/RTFE) – a synthetic fluoropolymer that is highly resistant to chemicals as compared with other plastics. Plus, PTFE lined seat has a low coefficient of friction which makes it ideal for low torque applications.

• Metal-to-metal (SS316 and Inconel) – Inconel butterfly valves are used for applications requiring heavy-duty seats such as in handling bulkier fluids. On the other hand, Stainless steel butterfly valves can be used in processing corrosive substances as they have a higher resistance to corrosion than Inconel.

5. Lever Handle - Basically lever handle is used to open and close the Butterfly Valve. It provides ease of operation at the expense of speed.It can be adjusted to various positon with the help of the gearbox

6. Nut - It is a fastener used in conjunction to mate multiple parts together

Advantages of Butterfly valves

• Compact design requires considerably less space, compared to other valves
• Light in weight
• Quick operation requires less time to open or close
• Available in very large sizes
• Low-pressure drop and high-pressure recovery

Disadvantages of Butterfly valves

• Throttling service is limited to low differential pressure
• Cavitation and choked flow are two potential concerns
• Disc movement is unguided and affected by flow turbulence