INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

High Suction Lift Pumps for sampling

High Suction Lift Pumps for sampling

(OP)
Dear All,

I am looking for a type of sampling pump (about 100 L/hr) that has a high suction lift of about 9m (Already considered all the loses).

As far as i know that some peristaltic pumps can achieve such a high suction lift. Is there any special types/alternatives of pumps capable of handling high suction lifts? besides having a vacuum pump.


Thanks

RE: High Suction Lift Pumps for sampling

Perhaps some details on what you are doing would be helpful, application, type of fluid, etc.

RE: High Suction Lift Pumps for sampling

What does this lift equate to in terms of either absolute pressure or m head of your liquid.

What is the vapour pressure and density of your product at sampling temperature?

What is your elevation above sea level?
Is the liquid exposed to atmospheric pressure or some other pressure

Anything close to or greater than an SG of 1 will be very difficult to source if you have to prime this. Without this information it's very difficult to advise.

Can you assume flooded suction at all times?

Or can you assume a vacuum pipe for initial fill?

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

RE: High Suction Lift Pumps for sampling

(OP)
What does this lift equate to in terms of either absolute pressure or m head of your liquid. (m head of liquid)

What is the vapour pressure and density of your product at sampling temperature? (Density 1030kg/m3, 2.4kPa, Seawater)

What is your elevation above sea level?
Is the liquid exposed to atmospheric pressure or some other pressure (about 7m elevation difference, atmospheric)

Anything close to or greater than an SG of 1 will be very difficult to source if you have to prime this. Without this information it's very difficult to advise.

Can you assume flooded suction at all times? (no)

Or can you assume a vacuum pipe for initial fill? (yes)

the installation will be something like that. The elevation as written above

_____Pump Ground Level__+1.7m(elevation)_
|
|
|
|Lowest Seawater level -5.3m(elevation)
|


Bottom of sump

RE: High Suction Lift Pumps for sampling

Not sure where you're getting 9m from - from those levels your true lift above liquid level is actually 7 to 7.5m.

for an ambient temp seawater solution that would give you an NPSH of around 2 - 2.5m
That's quite low but there are a number of pumps which can achieve that, though you might need to fit an inducer to the front end.

So long as you can prime the system with your vacuum line then you have a wide choice of pumps.

Can't quite see why you don't use a submersible pump or a vertical pump.

You probably want to avoid any sort of pulsating pump so if PD type then screw or gear would be best as opposed to piston or AODD.

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

RE: High Suction Lift Pumps for sampling

Come on guys,flow rate required is 100l/hr - forget standard pumps like piston, AAOD, PD unless into metering pumps and then you have 9m suction lift - pie in the sky stuff.
Look at airlift of some type for the eye-dropper amount requirements of 0.0277l/min.

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.)

RE: High Suction Lift Pumps for sampling

It does not make sense to have a sampling pump of this size. At the 1.7 l/min (100 l/hr) rate the lag time to move this sample from the source to the sampling point will probably be an awfully long time.

I think they may be better off installing a EASTERN CENTRICHEM centrifigal sampling pump at some intermediate level so that it is flooded at all times. With the larger pump, the sample can be pumped at a greater rate in a larger diameter pipe loop and discharged back to the source. Tap off that discharge pipe with a needle valve to get the desired sample. This will really improve the lag time. I think it may be more practical also

http://www.pulsa.com/products/pumps/eastern-series

You can even get a sumbersible sampling pump with a VFD on it

http://www.geotechenv.com/pdf/ground_water_samplin...

RE: High Suction Lift Pumps for sampling

Screw pumps have also a good lift capacity and low NPSHr however your flow is very low so that reduces the options (although some manufacturers have small screw pumps for dosing applications)

Small laboratory/pharma hose pumps are also a possibility.

And some small magnetic coupling gear pumps have small NPSHr (but I would recommend a foot valve with strainer as these pumps do not have any solids passage...

…although ‘QualityTime’ may be right and it has no point on taking a sample there. What about submersing the analyzer or probe? I assume ‘Nicwong7’ thought about that, but just in case!

RE: High Suction Lift Pumps for sampling

Hang on people,

I thought it was 100l/min - misread.

But its 100 litres per hour = 1.66 l/ min (0.37 gals/min)

That makes it 0.027 litres / SEC

Agree it's quite low speed but if it takes a while to get a sample, that's the OPs problem

We have no idea why they want a sample, how often they want a sample, what the diameter of the suction lift is ( it's only 7m to pump base level remember, not 9m)

LI

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

RE: High Suction Lift Pumps for sampling

Nothing better than a centrifugal pump. Low low maintenance

RE: High Suction Lift Pumps for sampling

23+ feet of lift is a lot for any pump...

Mike Halloran
Pembroke Pines, FL, USA

RE: High Suction Lift Pumps for sampling

There are a number of positive displacement pumps on the market for sampling. If the OP would just say what he is trying to do, it would be helpful. Otherwise, it is just a game of twenty questions.

Here is a bladder pump that will do the task:

http://www.solinst.com/products/groundwater-sample...

RE: High Suction Lift Pumps for sampling

bimr: correct, just another 20 question quiz to keep us awake and alert.

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.)

RE: High Suction Lift Pumps for sampling

(OP)
Hi All, First of all thanks alot for all your inputs. Just to give more information,

The sampling is done continuously feeding into the online instruments, it is an online monitoring to measure certain parameters of the feed water before misc filters downstream etc.

It takes about 2.5 minutes to get the sample. As the flow is very small, it is sized at an inch Pvc.

True that suction lift is only 7 to 7.5m + some pipe losses. Though i was thinking of a safety buffer and rounding up resulted in 9m suction lift as a design data for the pump supplier. Might be too much.. But thanks for the input @LittleInch, will look into that.

For pulsation type, we considered using peristaltic pump. We managed to find a supplier which guarantees 9.5m suction lift and with a dampener at the discharge line. What do you guys think?

Did consider submersible pumps as a solution at first, however, due to the location and the maintenance of this pump. Still preferred it to be on ground level.. Having said that, @QualityTime that GeoPump submersible pump seems quite interesting, might be feasible. Didnt know that there are such kind of submersible pumps available.

I guess i may look into some PD- screw pumps that some have suggested.

RE: High Suction Lift Pumps for sampling

I'd take a look at putting a small laboratory style pump way down in a dry caisson comprising ~7m of 4" or 6" PVC pipe with a cap on the bottom. Make a sealed door in the pipe near the bottom so you can work on the pump after lifting the entire caisson out of the water. The pump draws from a radial port in the pipe through a short piece of hose, and the pump feeds the sample out the top of the caisson through ~10m of hose. No suction lift required, so your pump choices are less limited.

For extra insurance, run a small rigid tube up the inside from near the bottom to a radial port near the top, cap the top, and pressurize the caisson with plant air regulated to a pressure equivalent to ~10m of water. If water spits out of that vent, you've got a leak down there somewhere, and some time to fix it before the pump gets wet.

Mike Halloran
Pembroke Pines, FL, USA

RE: High Suction Lift Pumps for sampling

I would just search "12V plastic bilge pump" and find one with enough head to use and then drop it off the side with a small rope.

I mean this is a very small flowrate and warm aerated seawater eats most steels so you end up needing brass or something which doesn't corrode.

Just go for simple.
Even these are 10 times the flow you need so maybe run a sampling loop and return most of it back to sea after a pressure valves?


http://www.asap-supplies.com/pumps/washdown-pumps

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

RE: High Suction Lift Pumps for sampling

Choose your pump material carefully for the conditions of service. The achilles heel of stainless steel is chloride attack. Sea water has chlorides. That is why they don't make the ship hull out of stainless steel

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close