design of pipe joints

Design of Pipe Joints

By:Er. Shankar Sehgal

Faculty of Mech. Engg., UIET,Panjab University, Chandigarh

Website: http://shankarsehgal.weebly.com

Pipes Materials

• C.I.– Low resistance to shocks and water hammering– Up to 0.7 Mpa only– Water and sewage systems

• Wrought Iron– Mass transfer of steam, air and oil

• Steel– Petroleum industry– Up to 4 Mpa and 440°C

• Brass– Pressure lubrication systems

Design of pipes

WhenD/t < 20σ/p < 6

WhenD/t > 20σ/p > 6

Design of pipes

• For C.I., Wrought Iron, C = 9 mm

• For steel, brass, C = 3 mm

Design of pipes

Design of pipes

Socket or Coupler Pipe Joint

Nipple Pipe Joint

Union Pipe Joint

Spigot and Socket Pipe Joint

Expansion Pipe Joint

Copper Corrugated Expansion Pipe Joint

Used for short length pipes only

Sleeve and Socket Type Expansion Pipe Joint

Sleeve and socket can have relative movements along the axis

Circular Flanged Pipe Joint

Circular Flanged Pipe Joint

Used for pressures up to 2 MPa

Design of Circular Flanged Pipe Joint

• Considering tensile failure of bolts:

• Circumferential pitch of bolts:

2

21

4

4

cdn

pD

AF

nD

p pc

Design of Circular Flanged Pipe Joint

• Bending failure of flange:

12

4

2

3

21

ff xt

yn

pD

tIM

y

Oval Flanged Pipe Joint

Used for pressures up to 15 MpaNumber of bolts = 2

Design of Oval Flanged Pipe Joint

• Considering tensile failure of bolts:

2

221

2

4

244

2/__

cd

pDDpD

AForcePackingForceFluid

AF

Design of Oval Flanged Pipe Joint

• Bending failure of flange:

12

24

2

3

21

ff xt

epD

tIM

y

Square Flanged Pipe Joint

Number of bolts = 4

Design of Square Flanged Pipe Joint

• Considering tensile failure of bolts:

2

221

2

4

244

2/__

cd

pDDpD

AForcePackingForceFluid

AF

Design of Square Flanged Pipe Joint

• Bending failure of flange across section AA:

Design of Square Flanged Pipe Joint

• Bending failure of flange across section AA:

12

2

____..24

42

2

32

1

21

ff ttDL

pressurewatertodueMBLpD

tIM

y

Seals

• To prevent leakage of fluids due to overpressure in an assembly where mating surfaces have relative motion

• Functions are:– To seal in oil, grease etc.

– To seal out dirt, contaminants etc.

– To maintain applied pressure or vacuum

Gaskets

• To create and maintain a barrier against flow of fluid across mating surfaces placed in an assembly relatively at rest.– Metallic gaskets

• Lead• Copper• Brass• Aluminium• Low Carbon Steel

– Non-metallic gaskets• Paper• Leather

Thank You