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Project Engineer
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Pressure Drop

08/17/2015 4:40 AM

If the pipe is open to atmosphere, Is there any pressure shown by the Pressure Guage from the pump discharge in service?
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Codemaster
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#1

Re: Pressure Drop

08/17/2015 4:49 AM

If you're a project engineer, why don't you think it through? And it's gauge.

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lyn
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#2

Re: Pressure Drop

08/17/2015 5:52 AM

Why not model it and see what you get.
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Tornado
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#3

Re: Pressure Drop

08/17/2015 6:15 AM

It depends on where the opening is the discharge pipe is, and the configuration of the pipe.

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texasron
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#4

Re: Pressure Drop

08/17/2015 7:41 AM

Yea, whatever the air pressure is at that location. Dia. of pipe, gradient of the pipe, What the fluid is ect.ect.

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Kulas
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#5

Re: Pressure Drop

08/17/2015 7:45 AM

would it made difference if we call it, drop of pressure

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SHOCKHISCAN
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#6

Re: Pressure Drop

08/17/2015 8:44 AM

Yes.

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Original_Macgyver
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#7

Re: Pressure Drop

08/17/2015 9:19 AM

Yes!

No!

Choose one then go hand in your resignation!

You are no project engineer if you cannot answer this benign question yourself!

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Kilowatt0
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#8

Re: Pressure Drop

08/17/2015 11:18 AM

42

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Original_Macgyver
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#10
In reply to #8

Re: Pressure Drop

08/17/2015 12:22 PM

I see 44 psi but there is a margin for error!

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Kilowatt0
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#11
In reply to #10

Re: Pressure Drop

08/17/2015 1:30 PM

Didn't you know? 42 is the answer to "Life, the Universe, and Everything"!

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#12
In reply to #11

Re: Pressure Drop

08/17/2015 1:39 PM

CRAP!!!! And I screwed it up by adding 2 PSI....... UGH!!!!

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Kilowatt0
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#13
In reply to #12

Re: Pressure Drop

08/17/2015 2:43 PM

Well, to be honest, I just got through with having cataract surgery on my second eye; so I might have had a parallax error, and just guessed at 42!

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#14
In reply to #13

Re: Pressure Drop

08/17/2015 3:52 PM

Hope you're feeling better... Take care.

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#9

Re: Pressure Drop

08/17/2015 12:13 PM

What's the airspeed velocity of the African swallow? But seriously, if there is no fluid velocity, there is no pressure drop, except . . . . . . Is the pipe open to the atmosphere 100 meters above the pump? The assumption here is that the pipe opening is horizontal with respect to the pump. Are there any inverted-siphons between the pump and the opening? What's the viscosity of the fluid? Is the fluid compressible? So many questions, so little time.
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SolarEagle
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#15

Re: Pressure Drop

08/17/2015 4:20 PM

Is there any pressure in a fire hose?

https://en.wikipedia.org/wiki/Fire_hose

....at a steady pump discharge pressure ,as the line size decreases and the length of the line increases, the pressure in the discharge line increases and the flow rate decreases...with the line fully open....

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#16

Re: Pressure Drop

08/17/2015 4:23 PM

So, if the discharge from the pump is open to atmosphere, why does it need a pressure gauge on it? Why not use the local weather forecast instead?

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#17

Re: Pressure Drop

08/18/2015 3:44 AM

So pump in service means its running? Just trying to comprehend the question.

The pipe is horizontal? Why not? Its pretty small isn't it? I mean the ID is smaller than the outside right? Or do you pump "it" along side the OD? Really just asking!

If the gauge shows 0 pressure what can you deduct from this? The gauge still shows something? Zero is something right! How about some 14 something psi. Or is the gauge reading in bar?

So many questions!

Look, I think you need to be more specific with your question. As a process engineer you should have learned that.

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Circuit Breaker
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#22
In reply to #17

Re: Pressure Drop

08/18/2015 5:20 PM

What if his gauge is in Roman numerals? -- JHF

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horace40
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#18

Re: Pressure Drop

08/18/2015 10:29 AM

Probably No! If the pipe was 1/4" long and 100 feet diameter, I would guess the gauge would show zero.

Probably yess! If the pipe was 1/4" diameter and 100 ft long, I guess the gauge will show full pump output pressure - if the gauge was at the pump end.

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#20
In reply to #18

Re: Pressure Drop

08/18/2015 11:04 AM

It's pointless to consider it, as we don't at what point the gauge is measuring, or the system layout, never mind the flow rate and pipe length/diameter. And of course the OP hasn't been back to clarify.

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horace40
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#21
In reply to #20

Re: Pressure Drop

08/18/2015 11:41 AM

...come to that, the gauge might on the oil pump for all we know...!

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#19

Re: Pressure Drop

08/18/2015 10:43 AM

Isn't that why they call it "gauge pressure", so you can define the "absolute" pressure?

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Users who posted comments:

agua_doc (1); Brave Sir Robin (1); Circuit Breaker (1); Codemaster (2); horace40 (2); IdeaSmith (1); Kilowatt0 (3); Kulas (1); lyn (1); Original_Macgyver (4); PWSlack (1); SHOCKHISCAN (1); SolarEagle (1); texasron (1); Tornado (1)

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