Can you tell me where can I find those articles about the pump piping
layout?
Thanks lot!
Robert Liu
-----Original Message-----
From: SARE, RALPH H. [mailto:SARERH@YANPET.SABIC.com]
Sent: Thursday, October 04, 2001 2:17 AM
To: 'PipingDesign@yahoogroups.com'
Subject: RE: [PipingDesign] High temperature Piping in Refineries
> From: Macharla, Hari[SMTP:HMacharla@mcdermott.com]
> Subject: RE: [PipingDesign] High temperature Piping in Refineries
>
>
> 1.For Rotating Machinery fundamental requirement for smooth running is
> alignment of Driven Equipment and Driver. This has to be ensured in all
> running conditions.
>
my comment. alignment of the driver and driven equipment is necessary but
has very little to do with the alignment of the equipment nozzle and piping.
You do reverse alignment (or laser) with the former and just check for
offset using dial indicator with the later. the method of correction and the
acceptance criteria is aslo different.
> 2.Any Additional loads on Machine Nozzles lead to disturb the alignment,
> and
> adversely affect the performance of Machine and its life.
>
my comment. if its below the API load (forces and moments) allowable then
its OK.
> 3.Sequence in Installation and Commissioning of a Rotating Machine, after
> fixing to foundation is as follows...
>
> * Align Driver and Driven Equipment, without connecting the Piping
>
my comment. this is confusing. if im going to pullout the motor to change the bearings or do re winding, it is not necessary to disconnect the pump to align the motor . after installing the motor (without disconnecting the pump piping suction/disch), then install the flex coupling. locate the magnetic center then do the alignment. as much as possible minimize disturbing other connection
Ensure the Connecting Piping Flanges are parallel and close to
> Equipment Nozzles, so that fixing of Piping should not disturb Machine
> Alignment.
>
my comment. Igor Karrasik, LC Peng and Heinz Bloch has written numerous
article related to good practice for the suction and disch piping layout.
Most has recoomneded of maintaing a five straight dia to reduce pipe strain
on the suction and disch nozzle.
> * Check the alignment Once again, after connecting the piping, whether
> any major disturbance is there (at ambient temperature). Now the Machine
> is
> ready for running. If cold pull is provided, it is next to impossible to
> get
> the alignment of equipment, after joining the piping to equipment.
> * Once the Equipment is run with Process fluid, after reaching to the
> operating temperature, again alignment may have to be checked and ensured
> based on the criticality of the machine.
>
my comment. how does one check the alignment on a running equipment?
normally we check the vibration, temp, flow rate. Vibration trending is what
we currently practice.
> In view of above, I am of the opinion that Cold pull can not be used for
> Piping around Rotating Machinery. However if nothing else can be done,
> issue
> may have to be resolved with Machinery vendors, so that they may plan for
> alternatives, if possible. But atleast I never had an experience of Cold
> Pull on Machinery.
>
my expereince. vendor is of little help with it comes to piping
layout.they're totally useless. but they may be help in improving pump
performance or MTBF.
>
> Hope it clarifies the issue.
>
> Hari Prasad Macharla
>
>
>
Your use of Yahoo! Groups is subject to <a href="http://docs.yahoo.com/info/terms/">http://docs.yahoo.com/info/terms/</a> Received on Thu Oct 04 13:56:00 2001
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