Mohamed,
I have has to make a few assumptions about the type of exchanger you are talking about. I hope I got it right.
The heat exchanger is generally a long vessel, and the tubes and the shell
will have different temperatures (otherwise it would not be a heat
exchanger) so obviously if you clamp the shell and the tubes together at
both ends they will put each other under strain. The hot component (shell
or tubes) will go into compression and the cold one into tension. That is
particularly bad for the tubes because they are often held in place by
frictional grip alone. There is no sense in putting those joints under
longitudinal stress. There is also no sense in putting the shell or the
tubes under unnecessary stress. That is solved by not connecting the tube
bundle to the shell at both ends. One end of the tube bundle is allowed
to move freely in the longitudinal direction within the shell. They
normally call that end the FLOATING end. The other end is just about
always fixed and I think it is this fixed end you are talking about.. This
arrangement still has to be made to work however in that it must be
possible to connect a pipe to the inlet of the tube side and also to the
outlet of the tube side. This can not be done on the floating end because
it is floating around within the shell. This is solved by dividing the
tube bundle into two distinct sections and making the two pipe connections
on the fixed side of the tube bundle only. The fluid enters one half of
the tubes on the fixed side, flows to the floating end where it is routed
into the second half of the tubes. It then flows back to the fixed end
where there is a second nozzle to discharge it. The fixed end is normally
called the channel because in section it has the shape of a channel. This
channel has the triple purpose of 1) clamping the tubeplate of the tube
bundle to the shell (thus fixing it) 2) dividing the tube bundle into two
so that the fluid can flow to and from the floating ends in separate
sections. That is done by installing a divider plate in the channel. 3)
providing a fixed place to install the inlet and outlet nozzles to the
tube bundle. The inlet to the bundle is located on one side of the divider
plate, the outlet is on the other side.
So you can see the channel end is the end where all the action takes
place. Where the tube side nozzles are located, where the tube bundle is
fixed and obviously where the tube bundle can be removed. That is simply
how the exchanger is designed.
Other contributors have mentioned the fixing of the exchanger to the
foundation. That is also an issue and I would normally expect the
exchanger to be fixed to the foundation at the channel end as well. As
you undoubtedly know, pipes expand when they get hot and one needs to
control the movement of the points where they terminate. Generally it is
better for the end points to be fixed and not moving around stretching and
compressing the connected pipes. The channel has two nozzle attached and
at least one nozzle on the shell side will be close to the channel. It is
generally a good idea to fix that end of the shell to the foundation and
to allow the other end of the shell to slide over the foundation to
accommodate thermal expansion. That arrangement normally places minimum
strain on three of the four pipes attached to the exchanger.
The above is a description of a floating end shell and tube exchanger.
There are a number of other arrangements that are common. If you can lay
hands on a copy of the TEMA standard (of the Tubular Exchanger Manufacturers
Association ) you will find details of just about every arrangement in common
commercial use.
Salaam
Gordon Reddek
I
"Mohamed Bharuk M." <m.mohamedbharuk@saipem-india.com>
20/03/2004 03:33 PM
Please respond to PipingDesign
To: <PipingDesign@yahoogroups.com>
cc:
Subject: RE: [PipingDesign] cyclone separator
Dear all
please tell me why in case of heat exchanger , the side in which tube
bundle is removed is normally fixed
M.Mohamed Bharuk
-----Original Message-----
From: <a href="/group/PipingDesign/post?postID=YdnB_0E6ajJm8oYFpbGLn9OHQmPN_U4MousMUcSyWcmlT7rB9WCcRteUIdA0X_LhUJy8q93MLO4GU6g">ABDUL__WASAY@ril.com</a> [mailto:<a href="/group/PipingDesign/post?postID=YdnB_0E6ajJm8oYFpbGLn9OHQmPN_U4MousMUcSyWcmlT7rB9WCcRteUIdA0X_LhUJy8q93MLO4GU6g">ABDUL__WASAY@ril.com</a>]
Sent: Saturday, March 20, 2004 8:48 AM
To: <a href="/group/PipingDesign/post?postID=MJSAND6VD33biLceaMmLElIgvhVJqrZMiW1Y6flNzRoUom9bmKwKT7_WxMui_tcMnVJ0DAHFwWTpJ0e8TV4yiv6aoA">PipingDesign@yahoogroups.com</a>
Subject: [PipingDesign] cyclone separator
hi!!!
Iam wasay
Can anyone give me detail (function ) of a Cyclone seperator and also its
scope.
regards
Abdul Wasay
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[Non-text portions of this message have been removed] Received on Mon Mar 22 18:07:00 2004
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