Biopowered - vegetable oil and biodiesel forum
Biodiesel => Biodiesel equipment => Topic started by: Julian on May 22, 2013, 11:19:37 PM
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After only a couple of uses my little Mono started leaking again. Took it apart and found this ... quite probably a lot to do with tardy workmanship the last time I took it apart ...
(http://www.biopowered.co.uk/w/images/4/43/Mono_ms10_damaged_ceramic.jpg)
Note the little lump of brass embedded in the ceramic face. The brass static half of the seal was quite badly scored too.
Scared of Mono's spares prices and knowing I'd got nothing to loose I decided to have a go at refacing the seal.
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The static half of the seal simply sits in a rubber bush in the pump housing and is quite easy to push out.
(http://www.biopowered.co.uk/w/images/3/34/Mono_ms11_seal_fixed_half_location.jpg)
(photo shows static half after sanding)
This was done by gently sanding the face of both seal halves on 800 grit wet and dry paper backed by plate glass. I used a little water and washing up liquid to lubricate things. Both halves were then lapped for quite a time direct on the plate glass using T Cut. This seemed to work quite well ...
(http://www.biopowered.co.uk/w/images/c/cd/Mono_ms12_lapped_seal.jpg)
The parts were cleaned thoroughly, lubricated with a little bio and reassembled. Reassembly was made much easer by turning a small chamfer on the spigot of the static half, to help it enter its rubber housing (in the absence of a lathe the chamfer could easly be filed with a little care).
(http://www.biopowered.co.uk/w/images/f/f3/Mono_ms13_seal_fixed_half_chamfer.jpg)
I've only run the pump for about 5 minutes tonight but it would appear that against all odds the seal is holding ... yet to see if this will last! I might run a book.
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nicey - fingers crossed - she lives again 8)
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Julian, it's been a long time since I last saw some one grinding on glass to achieve a flat surface.
Maybe it's knowledge that only us old farts poses.
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If you are into performance PC's you will be familiar with "lapping" which is done on glass. This is done to achieve a more thermally efficient contact between processor and its heat sink.
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If you are into performance PC's you will be familiar with "lapping" which is done on glass. This is done to achieve a more thermally efficient contact between processor and its heat sink.
You know when you're getting fussy with y'lapping, it's when you get the Jeweler's Rouge out.
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If you are into performance PC's you will be familiar with "lapping" which is done on glass. This is done to achieve a more thermally efficient contact between processor and its heat sink.
You know when you're getting fussy with y'lapping, it's when you get the Jeweler's Rouge out.
That's an arrestable offence, y'know ;)
Good luck with the pump Julian. Maybe some grit or muck got between the sealing faces?
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If you are into performance PC's you will be familiar with "lapping" which is done on glass. This is done to achieve a more thermally efficient contact between processor and its heat sink.
You know when you're getting fussy with y'lapping, it's when you get the Jeweler's Rouge out.
I had the engineer's blue out last week. But I was scraping, not lapping. Tedious, but we've now got a mill that actually slides rather than binding.
What are the dimensions on that seal?
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Well, gob smacked!
It's been running for about three hours dewatering and not a drop. Wonder if running on bio will show up any issues, bio being less vicious?
I'll add the details to the wiki page, although as far as I'm aware I appear to be the only member running an MS (select club! Hope others will join). I'll write the page as if it was all one repair ... I won't feel so stupid then (providing no one grasses me up.)
One good thing to come out of this is that I plumbed in a small dedicated vane pump to fill cubies which get carried to the car, while the Mono was out of action. The down side is it runs at about 6.5 ltrs/min and takes forever to fill the cubie! Really need to get Pipe Line Under the Garden operational.
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I used to lap Hillman imp heads on half inch plate glass !
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Added this to the MS page if people wouldn't mind having a read through to make sure that I've not made any howlers!
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May have to undo all the recent additions ... he go bugger up again this afternoon.
Me and this pump are headding for a big falling out soon!
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May have to undo all the recent additions ... he go bugger up again this afternoon.
Me and this pump are headding for a big falling out soon!
Julian, your pumpaphile status in now in question.
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May have to undo all the recent additions ... he go bugger up again this afternoon.
Me and this pump are headding for a big falling out soon!
Julian, your pumpaphile status in now in question.
Reserving comment until I've pulled the dammed thing apart again.
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What are the dimensions on the seal?
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What are the dimensions on the seal?
It may be a couple of days until I can pull the pump apart, I'll post after I have. Already having thoughts of making new parts ... how dare this thing keep leaking like this!
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So, the saga continues ....
Pulled the MS appart again today to reveal exactly the same problem as last time, a lump of brass embedded in the graphite rotating half.
After cleaning up, this is what was removed, note the score marks in the brass, static half.
(http://www.biopowered.co.uk/w/images/7/79/MS_3rd_rebuild_1.jpg)
On inspection the brass washer which sits between the spring and the 'O' ring in the graphite seal half was slightly chewed up and rough with sharp edges. Similarly the ends of the spring were quite sharp. Given the state of the washer I could only assume that the brass fragment lodged in the graphite came from here. That said there's no reason for the washer to get chewed up ... everything on the rotor rotates with it!
Anyhow, I decided to replace the brass washer (which was quite soft) with a steel item, so one was turned on the lathe. The edges of the new washer were broken using a wire wheel on a bench grinder. The ends of the spring were gently re-flattened on a grindstone and the external edges slightly champhered. The edges were then given the same treatment as the washer. Again the two halves of the seal were sanded and linished.
These are the components which went back in the pump.
(http://www.biopowered.co.uk/w/images/3/3d/MS_3rd_rebuild_2.JPG)
I tested it for a couple of hours this afternoon and not a leak in sight ... Ooo, that strange feeling of deja vous.
If this lasts I'll update the wiki page. I think it's tempting fate to do it straight away!
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Good news ... the seal has held up for quite a bit of oil transferring, a couple of hours dewatering reaching over 100°C, a full process and a demeth at 70°C.
So I hope it will be safe to add the comments to the wiki.
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Just added a 1:1 drawing of the gasket to the MS page.
Could someone confirm the pdf works ok please ... I don't have much luck with pdfs on here?
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It opens for me, but i dont know if it would print to the right size.
I think it would be good to have the OD listed, as then a user could print it, and check - at the moment, the only way of checking would be to physically measure the pump parts.
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OD is 140 if you wouldn't mind checking it, and good idea, I'll add it to the page.
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Added the dimension ... await your confirmation, thanks!
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Will check it tomorrow - just about to go to bed (and its only 20 past 9 - ughh!)