- my main reason for using GLOBE valve in bypass is cost - don't need
control or other benefits in a bypass. Also in some uses, a gate valve
that is almost always shut might not provide the long term security
(close when needed, minimal leakage, etc. - debris or rust has caused
some minor service problems in the dead leg)
- out of my realm of normal experience, so I'm not going to even try
to answer
- do thermal modeling or detailed heat exchange calcs or even just
talk to a vendor to have thenm use their guidelines on smaller dia pipe.
this is a fairly complex question. You must be familiar with
thermodynamics and heat exchange, teh process and it's needs, and
material interactions and properties. Material issues include cost,
delivery, temperature of process or utility pipe, and others. For
instance, open-cell fiberglass should not be used on some heat transfer
oils becuase of documented issues relating to reaction and heat of
adsorption that have resulted in spontaneous ignition of the oil in the
insulation, wih the resulting fire traveling along the entier pipe,
wrecking all kinds of havoc.
- This too is potentially complex, depending on what you need to know.
Acid brick or tile is made of materials that are by their nature
non-reactive with acid (obvious), but also that vitrify (become glassy)
when fired to preclude any hydration (abosrption) of spilled liquids and
have properties (such as very low thermal expansion coefficients) that
prevent them from cracking, weakening or otherwise changing in service.
If the codes or the engineer specify their use, follow thru. Of
paramount importance with the use of acid brick is installation and
grouting. Grout cannot be fired or vitrified, and will almost always be
the point of failure. Again, very low adsorption and thermal expansion
characterisitcs are required. Allow the proper conditions for
installing and curing the grout. Some of the best grouts contain lead
compounds, so they aren't allowed anymore in many countries.
... Bruce D. Bullough ...
Sebesta Blomberg & Associates
2381 Rosegate
Roseville, MN 55113
651-634-7344 (office)
651-634-7400 (FAX)
www.sebesta.com
-----Original Message-----
From: RAKESH PATIL [mailto:rpa@epc.ltindia.com]
Sent: Wednesday, May 01, 2002 2:21 AM
To: PipingDesign@yahoogroups.com
Subject: [PipingDesign] Piping Queries - II
Hi All,
Following are the things which i want to know from you -
- Why do we provide GLOBE Valve in By-Pass lines? Why don't Gate Valve?
- Why do we provide Rod on the sleeper/rack for simple resting
support?
- How to decide the thickness and type of insulation as well as
insulating material based on service and the temp of line?
- I want to know about the Acid Proof Tiling which is required in Acid
related areas. Can you please throw some light on it?
Waiting for your replies.
regards,
rakesh
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Received on Thu May 02 09:38:00 2002