Vessel DesignDesign of Openings

(Pipes & Manholes)

A Complete Manhole

Design of Neck:

Design of Gasket:Choose gasket type according to T & P

1. In Case of Vessels Under Internal Pressure:

Gasket type m

(Gasket factor)

y

(Seating

pressure, psi)

Working

temperature

(°C)

Working

pressure (atm.)

Rubber flat 1 200

< 100 < 10 Rubber with

cotton fabric

flat

1.2 400

Steel metal flat 5.5 18000

> 350 > 20 Aluminum

metal flat 4 88000

Ring steel 5.5 18000

Stainless steel 6.5 26000 > 350 > 20

Corrugated

metal

aluminum

2.3 2000

> 350 <20

Corrugated

iron 3 4500

Design of Bolts:

Design of Flange:

"4opis DD if atmP 6

"7opis DD if atmP 256

din (inch.) E (inch.)

1/2 5/8

1 17/16

2 2

Design of Flat Cover: (in case of man hole only):

Design of Reinforcement Ring: (for openings diameters > 2")

Design of Neck:

Take the gasket type the same as the material of construction of the shell.

In the equation of "Dog" previously mentioned, put "Pact" instead of "Pmax".

2. In Case of Vessels Under External Pressure:

Design of Gasket:

Design of Bolts:- The diameter of the bolt (din) will be always 1/2".

- Calculate Q"b only as it will has the largest value.

Design of Flange:

- For calculating "Ds" we will always use the equation:

Design of Flat Cover:- In calculating the thickness of flat cover (tf.c.), put "Pact" instead of

"Pmax" in the equation.

1. An absorption tower uses water to absorb NH3 from NH3 – air mixture at 30 ºC and 1.3 atm.g. Its diameter is 1.5 m and the total height of the shell is 3.75 m.

Water enters the tower from the top through a pipe of 1.75" diameter while the gas enters from the bottom through another pipe of 6" diameter. The absorber has a dished head and is made from C-steel (σall = 15000 psi). Calculate:

a. Thickness of shell at the top and at the bottom.b. Thickness of heads.c. Thickness of pipes.d. Dimensions of flanges and number of bolts in each.

Sheet 3