Pump no flow protection.

[fornhamspark]

I have an application where i need to detect no flow or a dead end condition. As the heat builds up in the pumped fluid could give rise to an explosion, so iam told.
The fluid is liquid fertilizer and quite corrosive, pipe size 6inch stainlesss steel flow rate 1000l/min.

Iam looking for instruments to use.
1. Paddle switch probably not last long as imersed in fluid.
2. Thermal dispersion needs to be wet all time
3. Mag flow very expensive.
4. Current, amps only change by 2%

Any suggestions please also what about looking at this from a temperature point of view.

 

[jmw]

Some options might include ultrasonic clamp on systems.
From the temperature approach I would suspect a differential switch that will alarm when the difference between the temperature in the fluid affected by the pump is significantly higher than a reference temperature elsewhere in the fluid.
Another option might be a pressure switch or a differential pressure switch.
By switch, mechanical switch or trip-amp.

JMW

http://www.ViscoAnalyser.com

 

[fornhamspark]

Thanks for the ideas,

1.Ultrasonic is too expensive to the client as they start around £500.00 mark.
2.Temperature difference is hard as only short run from suction to discharge is 8mts.
3.Pressure not sure as pump is mounted on surface then self primes from tank underground into vessel 3mtrs above ground so no delivery pressure to read.

Also no no return valve so pump has to self prime every start.

 

[JimCasey]

If the stuff is going to blow up if you dead-head the pump, £500.00 is a small price to pay.

You can just install a small recirculation (2 inch?) line from the outlet of the pump back to the tank from which the pump draws. Put a manually adjustable throttling (globe) valve in the line. Set the flow for the minimum required and padlock the handle of the valve in that position.

This way it will ensure that there is always enough flow to protect the pump, even if there would be no flow otherwise.

 

[controlnovice]

If the concern is 'dead-ending' the pump, pressure switch is installed on the discharge of the pump.

Another option for flow is external (clamp-on) ultra-sonic meter. No wetted parts with this one.

Is this a mag drive pump or canned pump due to the corrosive nature of the product?

Canned pumps can have temperature elements built into them. These are quite helpful.

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This is normally the space where people post something insightful.

 

[dcasto]

Vote with JimCasey, A 1-1/2" line with a union orifice is what the Dr ordered.

 

[jmw]

I guess the cost of protection always looks greater before an "excursion" than afterwards.
I always thought the only two ways to beat the bean counters were Health and Safety reasons or Environmental reasons.

JMW

http://www.ViscoAnalyser.com

 

[Cat3347]

6" mag meter to expensive for a potentially catastrophic application? Don't you just love bean counters?

 

[itsmoked]

Why would you not just temp sense the restrictions and pump points. Cheap, reliable, and to the point. (temperature!)

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[Skogsgurra]

Motor current may not change much. But motor power usually does since the power factor changes from something like .8 to less than .6 when 'dead-ending' (good expression that I just learned, thanks to controlnovice).

There are little relay-like devices that certainly cost less than GBP 500 that supervise power factor and can be used. You may need to install a current transformer (CT) if you do not have it already.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[JimCasey]

>>I guess the cost of protection always looks greater before an "excursion" than afterwards.
I always thought the only two ways to beat the bean counters were Health and Safety reasons or Environmental reasons. <<

The politicians always say the money is for the "chirruns", which apparently is pol-speak for the youth of our population.

 

[itsmoked]

dead-ending?? I have heard on the term "dead-heading". As in pressure head.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[Skogsgurra]

Dead-heading brings thoughts about the French revolution and madame Guillotine. Dead-ending is clear enough for me - and less bloody.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[ScottyUK]

Operating a pump against a closed valve or with no forward flow is known as 'dead-heading' in the UK.

Aside for Gunnar: What was wrong with the guillotine? A little more care on choosing whose head goes in and it could be a great machine. Crying out for some automation though!


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Sometimes I only open my mouth to swap feet...

 

[Skogsgurra]

Careful now, you limey!

I do not mind frog-eaters.

Gunnar, the rotten-herring-eater.



Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[danw2]

Gunnar, You're just going to have to enjoy your rotten herring on your own.

The US Food & Drug Agency prohibits the import of surströmming, so we in the US are denied that malodorous experience.

Dan

 

[Skogsgurra]

Don't forget! There's one snaps with each herring!
What about durian? Does FDA allow that?

Shouldn't this be red-flagged? It is awfully off-topic now. Isn't it?

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[itsmoked]

Or at least off-feed. Blarwagpt!

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[controlnovice]

"Dead Heading" is how I refer to it as well.

I used "dead ending" as it came from the OP.

______________________________________________________________________________
This is normally the space where people post something insightful.

 

[jmw]

Oh, not "dead herring"?
Sorry, I wasn't paying attention.

JMW

http://www.ViscoAnalyser.com