Pump woes.

[nigelb]

I had the pleasure of taking my pump apart last week and making some important mods as part of the plants annual maintenance. The maintenance was sort of forced on me due to my last batch requiring 3 stages in order to pass a satisfactory 5/45. It also used an extra litre of ASM in order to acheive the result.

So what did I do and why?

I figured that there may be some sort of blockage or restriction somewhere as there was no cavitation at the venturi. Something that I've always suffered from. This made me a tad suspicious of the flow rate. I decided to strip everything back and have a good look.

This is my pump. A Lowara 80lt/min.




I removed the 8 cap screws from the front housing..releasing the mounting bracket and stand at the same time.


After carefully removing the outer cover and inverting it, the internals, including the large outer O ring, can be seen


On the pump side of things the inlet to the impellors can be seen with what appears to be some aluminium tape stuck inside!!!


I gently prised it out.


On closer inspection there appeared to be a second piece and something else as well!!!


I reverse flushed the impellors with a high powered jet of water to dislodge anything else.


...and found this!!


Dispite the back of the motor having a slot for a screwdriver or similar to hold the shaft in place I could not undo the nut holding the impellors in place. Hence using the reverse flush technique.


I then used a screwdriver to prise out the inner cover and expose the small O ring.


With both O rings out, they were cleaned and inspected. They are both in excellent condition and OK to be re-used.


Both O rings were refitted during reassembly...(sorry about the blurred image)




..and finally the cover is bolted back on with the bracket and stand.


This is the sum total of what I removed. Two pices of aluminium tape, a small stone and two pieces of PTFE tape with some sort of new life form growing on it!!


The modification I made was the construction of a new venturi. With all the pipe work removed it showed that it wasn't one of my best. I also wanted to increase the throat size (re jamesrl) to 9.5mm. Something I couldn't do without breaking apart all the soldered pipework. A new venturi seemed the right thing to do.

The plant is now running again with no leaks. I am, as I write, drying 150lts of oil for a batch tomorrow.

[Tony]

I clean mine out by poking a bit of wire backwards through it... those closed impellers are a swine for blocking and my pumps have three sets back to back on the same driveshaft (in all fairness it's the front one that blocks and the rest are always fine).

Nicely built pump you have there sir!

[Jamesrl]

Are you sure you haven't got a hole in your oil pre filter sieve Nige.

In all the years I've been brewing I ain't not never had anything jammed in me impeller.

[nigelb]

The tape and the PTFE comes from my own construction carelessness. The stone...not a scooby doo!

The pump is fantastic...huge thanks to you Tony for linking me to it. £67 well spent and a nice trip out to deepest darkest Lincs to collect

[Head Womble]

I pulled my pump apart three time in my last batch, this was due to my immersion heater burning out in the gly wash stage.
It was a copper 18" one (all I could get at the time), the copper melted depositing small copper balls and fragments of the inner part into the impellor.
It's amassing how much I pulled out.

I didn't get all of it out as you can hear one or two balls circulating through the pump and pipework, so another strip down is on the cards.

[nigelb]

What sort of pump are you running Mark?

[nigelb]

Is anybody out there using an inline "Y" strainer? Makes me wonder if something like this could help prevent debris getting into the pump...or would it get in the way and interfere with flow?

[Head Womble]

What sort of pump are you running Mark?

I have one of JGS's 110plm pumps, with closed impellor.

[nigelb]

I've got one of those too.....still in the box. One day I'm gonna need it.

[Head Womble]

Is anybody out there using an inline "Y" strainer? Makes me wonder if something like this could help prevent debris getting into the pump...or would it get in the way and interfere with flow?

I suspect it would kill the flow rate, unless you used something massively oversized.

[Head Womble]

I've got one of those too.....still in the box. One day I'm gonna need it.

Good pumps, I got mine when he was selling the last ones off, £75 delivered was a steal.
The timing couldn't have been better as my old pump (still 110lpm) was leaking from the seal.

[Tony]

A Y strainer would be a problem for flow for sure.  Better to filter the oil - don't have to go crazy with filtration just enough to remove the big bits.

Regarding separating the impeller from the driveshaft, that slot in the back is totally inadequate for such a thing, you need one of those chain oil filter removers around the outside of the impeller to grip it, then you can undo the shaft nut no problem at all.

[nigelb]

Is anybody out there using an inline "Y" strainer? Makes me wonder if something like this could help prevent debris getting into the pump...or would it get in the way and interfere with flow?

I suspect it would kill the flow rate, unless you used something massively oversized.

Jim...have you got any data on "Y" strainer flow issues?

I wonder if it may be worth putting one in the pipework before the pump but on a by-pass.

[Jamesrl]

Is anybody out there using an inline "Y" strainer? Makes me wonder if something like this could help prevent debris getting into the pump...or would it get in the way and interfere with flow?

I have a 1" Y filter on the bench, the flow restriction is quite severe because of the perforated nature of the filter.

Might work if you have a 6" one in line, until it starts to block.

[nigelb]

Bit of a crap idea really...ah well!

I suppose Lorretta was right all along Tell her I take it all back