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All,
I want to try a little experiment.
I'm looking to put together an article for the Tips, Tools & Training area of the site, but I want to try a different approach .... I'd like to "crowd source" an article.
The Idea is that I suggest the title, such as "Pump Piping" above.
You then jump in with your thoughts - they can be very broad, or very specific to a part of the pump piping topic.
- Do / Don't lists
- Suction / Discharge
- By Pass
- Reducers
- Valving
- Etc.
The idea being that we use this thread to debate and comment on the various aspects of pump piping, drawing on the combined experiences of pipers using the forum (which must total thousands of years!).
I'd love to see plenty of input, and hopefully, if it works well, we'll do it for other articles.
OK?
Pump Piping .... GO!
Anton,
This is very good idea, So here are my first thoughts:
- Do: Make your Pump Piping fit the specifics of the situation. This means the type of pump, the commodity, the type of plant, type of project (Green Field or Brown Field) the piping Code for the project, the material, and all the other aspects of the installation.
- Don't: Don't assume that one answer fits all pump types.
- Suction: Avoid pockets, high point pockets and low point pockets.
- Discharge: Route piping to allow good access for operation and maintenance.
- By Pass: Not all pumps have a bypass line.
- Reducers: Consider the size, type, location and orientation.
- Valving: Valves in pump suction and discharge lines are there for isolation when the pump needs service. They are NOT for throttling the flow.
New here, but really like it!
I like the comments JOP.
Piping on pumps,
Do:
Suction reducer FOT - if service is liquid.
Suction reducer FOB - if service is slurry
Suction reducer FOB - if service is liquid, and the source is from above (trapped air should entrain back up the feed piping)
If you put an isolating valve on the discharge side, specify LO - locked open
Put a check valve on the discharge line.
Check straight length requirements for the suction.
Support the pipe properly.
Don't:
Run piping over the motor - it needs to be pulled out for service & maintenance, usually by crane.
"IF" the pump suction and discharge are either 125# or 250# the pump is cast iron, and whether it's listed or not, the pump nozzles are "flat faced"! To connect to it with steel spec piping you need to get 150# or 300# flanges with a FLAT FACE (where the raised face is machined off, creating a "flat face flange"). You will also need a full face gasket, spiral wound stainless steel gaskets won't work and WILL create the same problem as using a raised face flange, if one is used!
We are still looking for comments on this article, so if you have something you would like to add on the subject, login and have your say!
Suction strainers.
The proper way to install them, pointing the opposite direction of the flow. This makes sure that any debris is pushed to the outside edges of the flow stream instead of the middle of the flow stream where it could make bubbles/cavitation.
Supports.
Have supports as close to the pump nozzles as possible so that the least amount of pressure is transferred to the pump nozzles
Here's a good article explaining reducer placement / orientation at pump suctions, and why the used to be confusion around it.
Eccentric reducers and straight runs of pipe at pump suction
Supports
It is recommended to provide adjustable type supports in suction and discharge piping for pump alignment purpose.
Y-type strainers
In order to improve access for cleaning, Y-type strainers for horizontal suction pipe should be installed pointing downwards or at an angle of maximum 45 deg (check bolt holes quantity) from vertical. Install Y-type strainer away from the pump if located on vertical suction pipe.
The placement of reducers at pumps - Flat on top / flat on bottom, is dependent on whether the liquid source is above or below the pump.
Can't forget about a pump's vibration and the effect on adjoing piping. I recently completed a project that involved the evaluating the repeated failure of airlines supporting a solenoid for AOV control. The repeated failure caused the AOV to change positions and introduce system transients. Copper air tubing supporting the solenoid seemed to be right in resonance with the system vibration.
Turned out the fluid pulsations from a 3-piston positive displacement pump (75 gpm @ 2100 psi) were shaking the system.
Ended up replacing the copper air tubing with a short Sch 80 threaded stainless nipple. Quick fix mitigated failures the plant had been living with for years. Always amazed how the simplest fixes can have the biggest impact.
Technical Details: https://www.xceed-eng.com/preventing-fatigue-failures/
There is only one reason, safety is number one priority to setup everything and by mistake have any leakage then its not good for your health
Ayyurviva https://www.ayyurviva.com/gyno-comfort
If going out to dimension anything connected to or branching from a pump remember that the pump and or base may not always be square to the surrounding structure. We gather all of our own dimensions. we don't rely on a survey crew or laser scans. So step back and capture everything around that pump. Obstructions, drains, conduit trays you name it.
If you're doing a piping reroute or replacement to a pump and the pump itself is getting replaced, WAIT till the new pump is dialed in and completely installed before taking any dimensions.
Obtain cut sheets of the new pump.
If the spools are tricky/ odd degrees coming off the nozzles then see if tack welding the tie in flanges is acceptable for better field fit up as to not put stress on the pump nozzles.
If I can think of anymore I'll come back and add.
I have to get back to work!
