** 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...

Wow !
I would gladly pay 400 pounds for a genuine Dursley Lister even if it is the 3HP version.
Sadly.... it's 15,000 miles away from me separated by an ocean 

Veggie

Hi Glort,

Ha...Ha. Yes Dr. Who was inquiring. It's a Tardis machine. It actually holds 3000 liters of WVO but it looks very tiny. 

I have one of those pumps that you mentioned (330 gallons per hour). I use it on my BioD processor for circulation, but for this application the feed to the centrifuge is only 10 gallons per hour. Just a trickle.
That's why I was hoping to slow down the gear pump a bit.

I will dig around more to see if I can come up with a better pump running off mains power.
The centrifuge and pump will have to run for 3 hours per batch so I need a small pump that can handle that duty time.

Perhaps for the time being I can run this gear pump at normal speed with a bypass valve in the discharge line which can slip some of the flow back to the tank. I could adjust the bypass valve position until I get the desired flow rate into the Fuge.
The WVO is open circulation from the tank to the Fuge (no pressure) so maybe the pump will last a bit longer without pressure/amperage stresses.

cheers

Hi AdeV

When I tested the gear pump on the PWM controller it was not pumping liquid.
Just free wheeling and probably pulling only 1 amp.
Not sure why it would cook a controller. (Yes, I double checked the polarities    )

Veggie

Inline oil heater made from a pipe with threaded connections welded in place.
1000 watt , 120 volt element.

Here is a Rajkot factory.
Notice the paint booth near the end of the vid.
No repirator. ! 

https://www.youtube.com/watch?v=lcxat-Z1CBI

Veggie

Can I ask you a favour Veggie - how much does your bowl weigh, with lid? That's something else I'm contending with... the weight of the cast iron brake drum + a steel lid, might be a bit excessive...

Hi AdeV, the spinning bowl does not have a lid.
Oil overflows the bowl and is caught in the outer chamber.
https://www.youtube.com/watch?v=PsLGX-RbKuQ
The bow weighs about 5 lbs.
I got it here...
https://www.wvodesigns.com/rpc-poboy-kit.html.html
It comes with a special taper lock hub which anchors it to a 5/8 shaft.

Hi Glort,
Fortunately the oil I get has very little water. (I trained them well  )
However...there is always some water and my experience is that these types of centrifuges do a pretty good job of dewatering if the oil is hot enough.
In this example (not mine) you can see the steam leaving the processed oil ( at the 1:00 minute mark ).
https://www.youtube.com/watch?v=OksXHSWidMs
My unit has vapour ports in the lid and in the discharge line to channel moisture out.
1st generation fuges spin at 3600 rpm motor speed but with the use of 3 phase motors and variable frequency drives newer fuges can now run up to 6000 rpm making over 4000 g's. That really takes advantage of the sight specific gravity differences between water and oil. My thoughts are that multiple passes should eventually leave the oil quite dry, but until I run it ...I won't know for sure.

onward,
Veggie

Hi V,

While it will certainly clean the vast bulk of the debris, I, personally, am going a slightly different route in the bits I am getting together... I will be using a "fill tank" to dribble the oil through the fuge first time round to collect most of the junk... thereafter it will be a single tank system which will recirculate until shut down...

Hi Ed,

In a similar fashion, my raw oil will pass through a fine screen on the way into the single tank.
Everything else should get trapped by the centrifuge when subjected to 3000 G's (5000 rpm).

Based on the input from you fellas, I will proceed with a single tank system and see how it works out.

cheers,
Veggie