Pump sizing 2

[Remisero]

Hello,
I'm currently sizing a centrifugal pump to pump
demineralized water from a 300,000 gallon tank to trucks for electrical utility overhead line cleaning. The pump i'm currently considering indicates Maximum Working Pressure of 150psi, but existing piping system to which I intend attaching pump is class 150.

Can someone tell me what codes to look at for this
application in relation to safety factors.

Thanks

 

[BigInch]

Typically an ANSI#150 would give you about 250 psig at normal ambient temperatures, but you also need to check the piping. There is no guarantee that pipe pressure allowable must or will equal the flange pressure allowables.

Find out what design code was used for the existing system and you'll have your answer about how the allowable pressures are determined for that system.

Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[Artisi]

If you are transfering water from a storage tank to trucks, why do you need 150psi to do this.

Naresuan University
Phitsanulok
Thailand

 

[BigInch]

Maybe he's attaching the pump discharge to the 150# line.

Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[Artisi]

Ok ok- lets be a little more specific - what is the pump duty that you are selection for?


Naresuan University
Phitsanulok
Thailand

 

[Remisero]

Thanks for your responses,

I have a 40ft high demineralized water storage tank
and to fill a 2500 gallon tanker truck (by gravity) it takes approx. 1hrs. I need to install a pump to fill up the tanker trucks faster. The only point were I can tap into the demineralized water is a recirculation system in which piping is 150# class, the pump discharge line would be connected to the tanker truck via flexible fire hoses.

At this point I have looked at two candidate pumps:
1.- 78gpm @ TDH:65ft
2.- 400gpm @ Max. head of 194ft (100psi)

The 2nd pump would fill up the tanker trucks faster but want to make sure I am within safety factors of the system.

Thanks

 

[BigInch]

The first pump might be the best bet. The second could blow the trucks if pressure is not controlled. You'd have to put in a control valve to control discharge pressure to a level below the truck allowable pressure, which is not going to be much if anything. Alternate soulution might be a variable speed drive (vsd) for the 400 gpm pump. When you control the 400 gpm pump to limit output pressures to a truck allowable, I doubt you will get much more flow than the 78 gpm pump. Without the vsd you'll be discharging into a control valve at very close to maximum pressure output of the 400 gpm pump. The control valve would waste a lot of energy cutting down the pressure, hence VSD might be beneficial. Have somebody take a look at the output curve of each candidate pump and advise you which of the options you should use.

Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[Artisi]

To "blow the truck" assumes you are pumping into an unvented container. If you are pumping into an unvented container, how do you remove the air so you can actually pump into the container?
It follows then, that you must have a vented tank otherwise pumping cannot take place and therefore there is no problem of pressurising the tank unless you are able close the venting system (not a wise design for a simple water tanker)

The intial question was about pipe ratings which doesn't appear to be a great problem unless you intend shutting off the delivery line at the discharge point and operating the pump against a shut-head.

I don't have figures for the pressure rating of class 150 pipe but should be available from any pipe merchant.

Naresuan University
Phitsanulok
Thailand