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DecoctionMash
04-16-2014, 10:44 AM
Dear ProBrewer Sages,

I have a few thomson centrifugal pumps in my brewery. Two brewhouse pumps and a CIP pump. I have several issues that seem to be compounding.

First: Lately my pumps haven't been priming correctly unless there is a large volume of liquid in my tanks. They seem to pulse a small amount of water forward. When I shut them off air bubbles out of the intake. Obviously air is the problem, but what is causing it to intake air after priming? I worry I may have seal issues or something. But I have taken apart and inspected all the pump heads.

Second: Any idea how far away my centrifugal blades should be from the back plate? I can't seem to maintain a proper gap since tinkering with my pumps. It is either too close and grinds or is too far away and doesn't spin at all.

Third: What do I need to know about maintaining a centrifugal pump?

Thanks for your time,

Cole Brown
Eagle Creek Brewing Company

Edit: Sorry spelled pump brand wrong.

lhall
04-16-2014, 11:34 AM
Cole,

It sounds like your seal is leaking and drawing in air on the suction side, causing you to lose prime. Try replacing the seals.

The impeller should be about a credit card's width from the backplate. If I remember right, it is set with a set screw on the shaft.

The seal area on the impeller can get scored up too on these pumps. You can usually take the backplate to a local machine shop and have them turn it down smooth again for a case of beer.

Starcat
04-17-2014, 06:29 AM
We do not run this brand, but ALL pump OEMs should have the clearence to backplate published in the manual. IN the case of Waukesha, its .060. With that design, the backplate is what creates the correct tension on the seal along with the relative depth of the drive collar on the shaft. If these parameters are not correct you'll destroy seals quickly.

CPESystems
06-06-2014, 04:14 PM
It sounds like the pump is air locking. The air is probably not coming from a leaky seal but from the hose or pipe after the pump. A couple of things to try.

1) raise the discharge hose so the air trapped inside can get out the end. If it is a long hose coiled around like a snake on the floor make sure there are no high spots.

2) Loosen the clamp on the pump head and turn the casing slightly to that the discharge is at a 45 deg angle pointing left (when viewed from the front) this is the best set up for evacuating the air from the pump.

3) Install an air relief valve (like this one http://www.cpesystems.com/products/60arv-air-relief-valves (http://www.cpesystems.com/products/60arv-air-relief-valves) )on a tee on the outlet of your pump. This will allow the air to escape but will close up when there is product in it.

BrewinLou
06-16-2014, 08:26 AM
There is not a lot of play in the set point for the impeller. There are two set screws on the impeller shaft the let you set the position of the impeller shaft on the electric motor shaft.

Gbbc
07-10-2014, 03:21 AM
Dear ProBrewer Sages,

I have a few thomson centrifugal pumps in my brewery. Two brewhouse pumps and a CIP pump. I have several issues that seem to be compounding.

First: Lately my pumps haven't been priming correctly unless there is a large volume of liquid in my tanks. They seem to pulse a small amount of water forward. When I shut them off air bubbles out of the intake. Obviously air is the problem, but what is causing it to intake air after priming? I worry I may have seal issues or something. But I have taken apart and inspected all the pump heads.

Second: Any idea how far away my centrifugal blades should be from the back plate? I can't seem to maintain a proper gap since tinkering with my pumps. It is either too close and grinds or is too far away and doesn't spin at all.

Third: What do I need to know about maintaining a centrifugal pump?

Thanks for your time,

Cole Brown
Eagle Creek Brewing Company

Edit: Sorry spelled pump brand wrong.

Hi Cole,

Just saw this after posting in another Thread. Have you sorted out your problem? If so, what was the problem? I have EXACTLY the same issue with my centrifugal pump. I seriously need some help as this driving me crazy.

Cheers

CPESystems
07-10-2014, 08:58 AM
Hi Cole,

Which of the three issues mentioned are you have problems with?

Gbbc
07-10-2014, 01:52 PM
Hi Cole,

Which of the three issues mentioned are you have problems with?

Hi,

My problem with our 114 is the same as problem number one with Cole.

CPESystems
07-10-2014, 02:18 PM
Try turning the pump head so the the outlet is pointing at a 45 deg angle to the left (when viewed from the front) this will help the air get out of the pump head. Also try to keep the inlet hose short and both the inlet and outlet hoses flat on the ground to let the air out of the pump.