The document discusses different types of end closures used in pressure vessels. It describes flat heads, which are simple plates used for small vessels, and various formed heads including plain formed, torispherical dished, semi-elliptical dished, hemispherical, and conical heads. Each type is suited for different pressure ranges and vessel orientations. Equations are provided for calculating the required thickness of each head type based on design pressure, inner diameter, and material properties.

1. SHRI S'AD VIDYAMANDAL INSTITUTE OF TECHNOLOGY
Branch : Mechanical Engineering
Semester : 5 Sem
Year : 2015-2016
Subject : Design of Machine Elements (2151907)
Presentation Topic : End Closure of Pressure Vessel
Presentation By : Nilrajsinh Vasandia
Enrollment No : 130454119006 (New), 130990119060 (Old)

2. Outline:
• What is Pressure Vessel ?
• End Closure in pressure vessels
• Types of End closure
• Reference’s

3. What is a pressure vessel ?
• A pressure vessel is a closed container designed to hold gases or
liquids at a pressure substantially different from the ambient
pressure.

4. End Closure in Pressure Vessels
• Closing end of the pressure vessel is called as End closure. Also it is
referred as Manhole.
• Types of End closure are:
• Flat Heads
• Formed Head
The heads are either welded or bolted with the main vessel shell

5. Flat heads
• The flat heads or plates are the simplest type of end closure used only
for small diameter vessels.
• They are also used as manhole covers in low pressure vessels and as
covers for small openings.
• The thickness of the flat head is given by,
C
Pi
diht 

7.0• th = thickness of head
• di = inner dia of vessel shell
• pi = design pressure, N/mm2
• σ = allowable tensile stress, N/mm2
• C = corrosion allowance
th
di

6. Formed Head
• The formed heads, which are commonly used in pressure vessel, are
commonly used in pressure vessels, are normally fabricated from a
single circular flat plate by forming.
• Different types of formed head are :
1. Plain formed head
2. Torispherical Dished Head
3. Semi-Elliptical Dished Head
4. Hemispherical Head
5. Conical head

7. Formed Head: Plain
• The plain head formed head are used for
horizontal cylindrical storage vessels at
atmospheric pressure.
• They are also used for the bottom ends
of vertical cylindrical vessels that rest on
concrete slabs and do not have diameter
in excess of 7 meters.
• The thickness of the plain formed head is
given by,
C
Pi
diht 

4.0
• th = thickness of head, mm
• ric = inner corner radius, mm ≥ 𝑜. 1di
• Sf = straight flange length, mm = 3 th or 20 which ever is greater

8. Formed Head: Torsional Dished head
• The torispherical dished heads are used
for vertical or horizontal pressure vessel
or horizontal pressure vessel in the
pressure range from 0.1 N/mm2 or 1.5
N/mm2
• These type of heads are shaped by using
two radii : the dish radius or crown radius
(Rc) & inner corner radius or knuckle
radius (ric)
• The thickness of the torispherical dished
head is given by,
Cht 
pi0.2-all2
cif RpK
 








ic
c
f
r
R
kWhere 3
4
1
,

9. Formed Head: Semi-Elliptical head
• The Semi-elliptical dished heads are used for
pressure vessels above 1.5 N/mm2 pressure.
The ratio of the major axis to the minor axis is
generally taken as 2.
• The thickness of the semi-elliptical dished
head is given by,
Cht 
pi0.2-all2
cif dpk

 2)(2
6
1
, 1KkWhere f 
• S
f = 3 th or 20 mm, Whichever is greater

10. Formed Head: Hemispherical head
• The hemispherical head are strongest of all the
formed heads. They are free from dis-
continuties and hence used in high pressure
vessels.
• The thickness of the semi-elliptical dished
head is given by,
Cht 
pi0.4-all4
ii dp

• S
f = 3 th or 20 mm, Whichever is greater

11. Formed Head: Conical Head
• The Conical heads are widely used as
bottom heads to facilitate the removal
or draining of the material.
• The semicore angle is usually taken as
300.
• The thickness of the semi-elliptical
dished head is given by,
Cht 
 cospi)-all(2
ii dp
• S
f = 3 th or 20 mm, Whichever is greater