Re: surge question

From: <Erik>
Date: Wed Dec 24 2003 - 08:17:00 EST

Hi Omid,

What is the diameter of the pipe, pipematerial and pipe profile (are there high points in the pipe line?)?
What is the Friction Torque:To restart the pump or pumps you need to write a VBA script in a Torque Controller where you need to know the Torque v Speed.

Best Regards,

Erik
-------Original Message-------

From: PipingDesign@yahoogroups.com
Date: dinsdag 23 december 2003 19:18:26
To: PipingDesign@yahoogroups.com
Subject: Re: [PipingDesign] surge question

Dear Erik

This is pump characteristics:
PUMP:RADIAL FLOW :
   Rated Flow = 0.62 <m3/s>
   Rated Head = 41 <m>
   Rated Speed = 990.005 <r.p.m.>
   Rated Power = 400 <kW>
   Pump Inertia = 1.1 <kg m2>
   Motor Inertia = 17 <kg m2>
   Speed Ratio = 1 <>
   Friction Torque = 0 <N m>
   Sub-form : Thermal Capacity :-
   Initial Speed = 990.005 <r.p.m.>

and accumulators:

ACCUMULATOR : : 012001 : 17/12/03 : 11:27:06    Group : AIR VESSEL
   Outflow Loss = 1 <>
   Inflow Loss = 1 <>
   Diameter of Inlet = 0.6 <m>
   Horizontal X-Sectional Area = 4 <m2>
   Accumulator Height = 7 <m>
   Base Level Above Reference = 2.88 <m>    Polytropic Index = 1.4 <>
   Vapour Pressure = 0.02062 <bar>
   Liquid Type = 2
   Sub-form : Thermal Capacity :-
   Liquid Level = 5.5 <m>

normally we use compressor to balance the pressure of the tank.

if you need additional info please let me know.

Best regards

Omid

• Erik <erik.scheir@pandora.be> wrote:
  > Hi Omid,
  >
  > What kind of tank are you talking about?
  > Is it an accumulator or a bladder or a vented air
  > vessel?
  > What are the pump characteristics? (Curve, Moment of
  > Inertia,...)
  >
  > Erik
  >
  > -------Original Message-------
  >
  > From: PipingDesign@yahoogroups.com
  > Date: zondag 21 december 2003 15:31:59
  > To: pipingdesign@yahoogroups.com
  > Subject: [PipingDesign] surge question
  >
  > Hi
  >
  > I am working as Design engineer in a consultant
  > engineers, I am modeling a waste water pump station
  > the flow rate is about 1.86 cu meter per sec. for
  > surge analysis I assumed that all 3 pumps will
  > tripped
  > and from the down and up surge analysis , I find out
  > that a 55 cubic meter tank is enough to surge
  > shaving,
  > from the software I got that around 5 to 6 min
  > needed
  > to eliminated all the surge effects but my colleague
  > who has 18 years experiences says that just 5 sec
  > needed can any body help me ?(the whole net is
  > around
  > 2.5 km). also for restarting I got from the software
  > that 1 pump restarting is most critical from 3 pumps
  > restarting (although I know that it is impossible to
  > restart all 3 pumps together). Does it make sense?
  >
  > Best regards
  >
  > Omid
  >
  >
  >
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[Non-text portions of this message have been removed] Received on Wed Dec 24 08:17:00 2003