Inspection of Dished ends
Inspection of dished ends is the major parameter in manufacturing of pressure
vessel, storage tank its, so during inspection of dished end the each type of
dished ends have there certain tolerance and acceptance criteria on the basis
of this inspection done. Sometimes the dimensional tolerance and acceptance criteria
depends on client code or respective standards.
DP test for detecting discontinuities near to the surface is applied on Whole dished end inside and outside at the time of inspection,picture of dished end shown below,
Pic01
Following parameters should
be checked while inspection of Dished ends,
A) First stage of inspection is checking of heat
no. / plate no., job/tag no., material grade etc. punched on dished end is properly
and accurate or not.
B) IDCF : Inside Diameter Circumference
checked with the help of measuring tape of dished ends as per requirement
accurate or not.
C) Thickness checking : Thickness of
Dished end checked at knuckle area and crown area specially and checked whether under tolerance as per respective
code/standard.
The thickness measurement picture shown below,
Pic02
Pic02
D) Inside height : Inside height of
dished end is in under tolerance or not.
The inside height of dished end checked with help of measuring tape, picture of measuring inside height shown below,
Pic03
Pic03
E) Profile : Profile of the dished end
is checked inside and outside with help of template ( Layout of template
required to check as per requirement) so we can find under crowning and over
crowning of dished end.
With help of template checking of crown/knuckle shape shown below by picture,
Pic04
F) S.F. : Straight Face (S.F.) required
to check as per engineering drawing or as per requirements properly punched or
not.
G) Edge preparation : Edge preparation
of dished end properly mention as per requirement or not.
The edge preparation of dished end required as per edge configuration mentioned on engineering drawing, the picture of such edges preparation shown below,
Pic05
so during inspection of formed dished ends lots of parameters checked like visual inspection and defects open to the surface and if the given dished end formed in number of petals the joints should rephotographed before inspection.
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