Standard Piping Fittings.

Basic Details of STANDARD PIPE FITTINGS

INDEX :

1. Elbows

2.180° Returns:

3. Tees

4. Cross

5. Caps

6. Reducer

7. Stub ends

8. Couplings

9. Swage Nipple

10. Union

11. Special Fittings

What is Elbow in Piping .

 

•  An elbow is a pipe fitting installed between two lengths of pipe or tubing to allow a change of direction, usually a 90° or 45° angle, though 22.5° elbows are also made.

•  The ends may be machined for butt welding, threaded (usually female), or socketed, etc.

• Used to change the angle or direction of the pipe run. Most commonly in 90 degrees and 45 degree turns. 

• A pressure pipe fitting designed to provide an exact change in direction of a pipe run.  
• Steel pipe elbow is a key part in a pressure piping system used to change the fluid flow direction. 

Types of Elbow.

 45° Elbows.

 90° Elbows.

 LR Elbows (Long Radius).

 SR Elbows (Short Radius).

Elbows: - 

• Elbows are used to make 90 deg. or 45 deg. changes in the direction of run pipe.
•  There are two types of 90 deg. butt-welding elbows available for use. 
• These are the long radius and short radius elbows. 
• The long radius elbows have a bend radius of 1.5D, where D is the nominal size, whereas the short radius elbows have a bend radius of 1D.
• The 45 deg. elbows are of 1.5D. Radius.

2.180° Returns:- 

• Returns change the direction through 180 deg. This is mainly used to heating coils, heat exchangers, etc. Returns with 1.5D radius and 1D radius are available.
• 180 degree elbow is like 45 or 90 degree elbow,but the flow direction change is 180 degree.
• It looks like the flow fluid get back to the same direction from the joint. The shape is like two 90 degree elbows welded together.It is also called U bend or return bend.

3. Tees:- 

• Tees are used for branching off. For low pressure services, branching off is done by direct welding of branch pipe to run pipe instead of using a standard tee. In certain cases, reinforcing pads are used for structural stability of such connections. 
• The branching schedule specified along with piping specifications explains what sort of a branch connection is to use for that particular piping class.
• Pipe tee fitting is a fitting that has a T shape. It has two outlets at an angle of 90° each and one main connection line. It is a pipe that has adjacent outlets and used to connect pipes at 90° angle. 
• Pipe tee fittings are used for commercial as well as industrial applications.
• Tee is one kind of pipe fitting which is used for dividing main flow to two streams or combining flow from two streams.The shape of a pipe tee is like the English letter “T”,so we call it Tee.

Cross: - 

• This is a fitting very rarely used in piping system. There are two types of crosses, the straight and reducing. 

• To reduce the inventory, it is preferred to use tees except where space is restricted as in marine piping.
• Cross type fittings contains 4 opening in 4 directions. These are connected when there are 4 pipes are meeting at a point. These fittings generate more amount of stress on pipe as the temperature changes, because they are located at the center of four connection points. 

Caps:- 

• A type of pipe fitting, often liquid or gas tight, which covers the end of a pipe. A
• cap has a similar function to a plug. In plumbing systems that use threads the cap has female threads.
• It is a type of pipe fitting which is liquid or gas tight, and is used to cover the end of a pipe. A cap has a similar function to a plug.

Pipe caps act as protective device and are designed to protect pipe ends of various shapes. 

Reducer:- 

• A reducer is a kind of pipe fitting used in process piping that reduces the pipe size from a larger bore to a smaller bore (inner diameter). 
• A reducer allows for a change in pipe size to meet hydraulic flow requirements of the system, or to adapt to existing piping of a different size.
• There are two types of reducers available, the concentric reducers and the eccentric reducers.
• When the center lines of the larger pipe and smaller pipe are to be maintained same, then concentric reducer is used. Pump discharge and vertical pipelines are also used.
• When one of the outside surfaces of the pipelines are to be maintained same, then eccentric reducers is used. Pump suction to avoid cavitations and to maintain elevation (bottom of pipe) in rack are also used.   

Stub Ends: - 

• To reduce the cost of piping, stub ends are used with backing flanges for flange joints when exotic materials are used in piping. There are two types of stub ends available,  the long stub ends and short stub ends. 

• Stub ends are specifies two classes, class A with radius and class B with out radius at the corner. Class B can be used with slip-on flanges.
•  Class A stub ends are used, the inner diameter of backing flange is chamfered for better seating.

Couplings:- 

• Full couplings are used to connect to small bore pipes as projection of welding inside the pipe bore, when butt welding is used, reduce the flow area. Half couplings are used for branch connections and reducing couplings for size reduction. 
• Reducing couplings maintain the pipe centerlines same and eccentric swage nipples are used to maintain the outside surface same for such systems.

Swage Nipple:- 

• Swage nipples are like reducers but are used to connect butt welded pipe to smaller screw or socket welded pipe. There are two types of swage nipples, the concentric and eccentric.
• A swage nipple is something similar to that of a reducer but it is used to join the butt welded pipe with a socket welded or screwed pipe. 

Like the reducer,swage nipple is also available with two variations:concentric swage nipple and eccentric swage nipple. 

Union:- 

• Unions are used in low pressure piping where dismantling of the pipe is required more often, as an alternative to flanges. Unions can be with threaded end or with socket weld ends. 

• There are three pieces in a union, two end pieces to attach to the run pipe and the third threaded piece to connect these two. The ball type metal seating ensures sealing.

Special Fittings: - 

• Weldolet
• Sockolet
• Threadolet
• Elbolet
• Sweepolet
• Latrolet

Weldolet: - 

• Weldolet is used for butt-weld branch connection where standard tee is not available due to size restriction and the piping if of critical/high pressure service.

Sockolet: -

•  Sockolet is used for socket welding branch connections, which require reinforcing pad.

Threadolet: - 

• Threadolet is used for threaded branch connections.

Elbolet: - 

• Elbolet is used for branch connections on elbows and have the profiles made to suit the elbow.

Sweepolet: - 

• Sweepolet is integrally reinforced butt weld branch connections.

Latrolet: -

•  Latrolet is used for branch connections at an angle.

It helps in changing the direction of water supply from main pipes to subsidiary pipes. Proper fitting also helps in checking leakage in the piping lines. Pipe fittings are an important component of the Piping system.

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