Side Channel Pump - no delivery

[oswald88]

Hi All
Recently we purchased a LPG bobtail with Pompetravaini side channel pump. it is driven by hydraulic motor. The problem is, when i try to deliver LPG through pump, i get high noise, hydraulic pressure is reaching upto 150 bar, but there is no delivery from pump. the pressure gauge in pump discharge is not even moving one bar higher. I tried to check the hydraulic motor, by reversing direction, even then no output. I seriously doubt is the pump is blocked mechanically, or what else might be the reasons for not getting discharge?

 

[lukin1977]

blocked LPG inlet to pump? closed pump inlet valve?

 

[oswald88]

all valve are sequenced properly. Inlet and outlet and other valves are opened.

 

[Artisi]

No LPG.

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.)

 

[LittleInch]

Definitely sounds like a pump or hydraulic motor which isn't going around.

Why?

Absolutely no idea, but I think you need to strip it down and see what is seized or broken. Take the motor off first and see if it goes round. Then see if the pump shaft will turn with the motor off.

I can't find any details on this pump so unless you provide a few more details we're not going to get very far, hence the rather short answers given to date.

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

 

[oswald88]

I disengaged hydraulic motor from pump and checked, its working fine. The pump shaft has no play in it. I tried rotating manually it was not possible. I suspect that, if the manufacturer has packed with a fluid to protect the pump, which is blocking its operation.

On the other hand, supplier claims he tested it successfully. Seriously puzzled.

 

[LittleInch]

Sounds like its time to take the pump apart....

Or just buy another one?

No idea which is cheaper overall

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

 

[Artisi]

Well well well, what a surprise, I couldn't rotate the pump shaft. No problem that's how all pumps operate.

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.)

 

[Artisi]

"Seriously puzzled"
So are we, it would be interesting to know how the unit was checked for correct rotation before it was put into service.

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.)

 

[oswald88]

Well, I suppose the manufacturer has packed with a protective fluid during transportation. If so how to remove that fluid and what is the commercial/chemical name of it?

 

[LittleInch]

It should still flow out of the pump. No one is going to introduce something which turns solid into a pump and you don't normally need to do anything to a pump to transport it, especially one which is attached to a road truck...

Between"testing" it and now something has broken or got jammed in the pump. Stop messing around and dismantle the pump. There is no mysterious "protective fluid".

Why on earth do you think the manufacturer has done this? Did someone tell you or are you just clutching at straws to prevent you taking the pump apart?

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

 

[Artisi]

Depending on how the impeller is attached, might have been started in the wrong rotation and the impeller had unscrewed and jammed the pump.
Agree with LittleInch, dismantle the pump is your only option

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.)

 

[oswald88]

Well, I will dismantle the pump and update you guys. Thanks for your suggestion. Will update with photos soon.

 

[Compositepro]

I once had a pump that did not work when installed. The installers had neglected to remove the plastic protection plug on the inlet. It had been pushed into the inlet port and the pipe was screw-in over it.

 

[oswald88]

Finally, dismantled pump, it was rusted, mechanical seal was broken. It was struggling to rotate which might have resulted in broken mechanical seal. What are your views? Kindly find the pictures attached

 

[Artisi]

New pump just purchased?
Send it back to the supplier with a please explain note attached.
I can see any connection between rust and the mechanical damage to the mech seal.

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.)

 

[LittleInch]

I wouldn't call that rusted, but clearly not well lubricated. Had it been in storage or not used for a few months?

Clearly anything with broken bits of metal wandering around it could get stuck, but fall out when you dismantle it. Those bits looked quite big.

Difficult to know exactly what we're looking at without a diagram, but hope you can fix it and now follow the pump maintenance and startup instructions for a long life...

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

 

[Compositepro]

That style of sump must be primed with liquid in order to function and can easily get vapor-locked. Are you sure that liquid can get to the pump by gravity or by venting the vapor out of the pump. Much of the damage shown in your pictures could be caused by just running the pump dry.

 

[oswald88]

Liquid LPG flow by gravity as the pump is mounted just below the tank. We have many vehicle in such mounting which are working fine. But I agree, this failure is due to dry run. I ensured the flow by checking internal valve of the tank and cleaning strainer, there is no issue with suction.