Author Topic: WVO Centrifuge Design - thoughs ?  (Read 5993 times)


  • Keep Calm and Start the Lister !
  • Hero Member
  • *****
  • Posts: 583
    • View Profile
Re: WVO Centrifuge Design - thoughs ?
« Reply #30 on: July 22, 2018, 10:46:46 PM »
** UPDATE **

I decided to go with mechanical flow control since I had most of the bits and pieces in my box of fittings.
The gear pump now has a discharge bypass which can relieve flow back to the suction side of the pump.
The RED valve lever controls flow. The gear pump can run at it's rated speed for the rest of it's life. (which according to Glort may not be for very long  ;) )
The unit is almost ready to fire up.
Next is to mount the centrifuge motor variable frequency drive in a box to hide the 240 volt connections.
I may also add a switch on the front of the box to allow for quick power kill.

Here's the  latest...

- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- Kubota Z482 - 4kw
- JiangDong R165 Air cooled - 2 kw


  • Hero Member
  • *****
  • Posts: 772
    • View Profile
Re: WVO Centrifuge Design - thoughs ?
« Reply #31 on: July 22, 2018, 11:36:45 PM »
Hey Veggie,

A little trick I often pull with pumps is to use a regular water type stopcock type tap/valve in place of your ball valve to prevent overpressuring and stalling the pump....

You mod the stopcock by removing the rubber washer and then placing a fairly strong spring between the spindle and the seal holder... As you screw the tap closed, the spindle pushes the seal holder onto the seat and increases system pressure... this allows you to adjust flow later on in the line without stalling the pump... A full seal is not required in this application, hence the removal of the rubber washer

Just a thought...

12/1 750RPM/9HP Roid 5kVA- WMO Disposal/Electricity & Hot Water Gen
12/1 650RPM/8HP Roid 4.5kVa - Demon Dino
Chinese Yanmar - Silent Runner with AutoStart
Classic Komatsu 1963 Dozer/Fergusson 35 Gold Belly ...
Bikes,Cars,Gunsmithing & Paintball...Oh yes, a 5Ha open air Workshop to play in!


  • Hero Member
  • *****
  • Posts: 2783
    • View Profile
Re: WVO Centrifuge Design - thoughs ?
« Reply #32 on: July 22, 2018, 11:47:22 PM »
Nice tip, Ed.  Veggie, does your gear pump already have an overpressure bypass relief internally built in?  If so, no worries on the ball valve.  Ball valves are great- but not so great for flow regulation near the low end, so Ed's solution solves both blowout and regulation adjust- assuming you have the right force spring.


  • Hero Member
  • *****
  • Posts: 1381
    • View Profile
Re: WVO Centrifuge Design - thoughs ?
« Reply #33 on: July 22, 2018, 11:51:10 PM »
Hi Veggie, been watching your build with great interest. Nice work and great paintwork.
I run a couple of VFD  controllers in my joinery shop. Please be aware that they have internal cooling fans and create a lot of heat under heavy loads or long runs. You will need to cut some ventilation holes in your enclosure or things will go bang. Please don`t ask me how I know or how much it cost.
Here in Australia we have problems with mud wasps and other creepy crawlies that love to get into electrical enclosures so I now cover all ventilation slots/holes with fly screen mesh, have to blow the dust out of them regularly.

Looking forward to seeing it running,


  • Administrator
  • Hero Member
  • *****
  • Posts: 588
    • View Profile
Re: WVO Centrifuge Design - thoughs ?
« Reply #34 on: July 23, 2018, 08:18:47 PM »
If it's anything like my cheap* Chinese gear pump - and it looks identical - it won't need an over-pressure or bypass system: the gears mesh so badly it'll just start spinning the oil if the back pressure's too much for it. Beware it's power consumption, though, which will soar above it's rated value and will cause overheating and damage in next to no time.

It's also hopeless if there's any pressure behind it: The oil/fluid will simply push past the gears and through the outlet pipe. A valve of some kind immediately before the pump would be a wise move, unless it's specifically lifting the working fluid against gravity, in which case you'll be fine (but it'll lose prime every single time you stop it; not a problem if you're not lifting more than about 6ft, as it will self-prime readily enough).

You may be getting the impression I'm a bit unimpressed with my gear pump.  ::)

* Not that cheap either... about 3x the price of a diaphragm pump of slightly lower rating which - in practice - performed better with a lower electrical load.
1x Lister CS Start-o-Matic (complete, runs)
0x Lister JP4 :( - Sold to go in a canal boat.