Relationship between pump discharge piping length and pump flow

[NovaStark]

Good day all,

I am trying to find any information I can on how the length of piping of a pump's discharge affects its performance/operation.

Consider a single stage OH type pump which takes atmospheric hydraulic oil and pumps it to a compressor at 180 psi. Suction enters the pump horizontally and discharges vertically.

If the distance between the discharge nozzle and outlet piping valve is 2 feet, how would this affect the performance/operation of the pump if the distance is reduced to 1 ft or even 6 inches ?

The main reasoning would be to remove as much air pockets as possible in the piping which is currently affecting the pump's performance.

 

[LittleInch]

Artisi,

Your pump knowledge is greater than mine, but a single stage OH pump is typically what I show as a section. That's why they often have a vent plug on the top of the casing.
The cutaway shown by the OP is a scrape from the flowserve site and it's not clear if this is the actual pump or not.

It's clear from a bit of a search around that some top centre line pumps achieve this by bending the discharge across.

Some top discharge pumps do truly have the discharge pipe able to vent the entire casing and some don't.

The actual point where the "lip" is might be a bit higher, but there is a void at the top of the pump shown by the OP.

So maybe my theory is junk - needs some more definitive information (actual photo or pump cutaway drawing would help...) not a default picture from the web.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Artisi]

40 posts and still floundering around in the dark without any real data.
Seems it's about time to employ an experienced pump engineering on site to sort out the problem.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[NovaStark]

@LI/Artsi:

In this scenario, wouldn't the hole in the piping create a pathway for air to get into the discharge piping?

I'll take a photo once I get usb access to upload a photo.

With Pump A online and Pump B off, I did open the local PI on Pump B's discharge and no oil came out (and the pressure read 0 psig if I remember correctly).

While we don't have an actual flow measurement, I suspect the actual flow (whatever it is as the curve is probably incorrect) is a non-issue or probably I am not understanding the issue as we did see that the shutoff pressure can be achieved in a way.