I still have my Absolute Cent #003 and I think I am having a problem will controling the flow into the machine. Right now I have a tank above the Centrifuge that goes to a ball valve(1/4) this flows thought a 5/8 heater hose to the factory 1/2" ball valve. I change the fitting on the pipe that drips inside the bowl to a 1/8 hose barb. The output is 1/2" PVC if that matters.

The problem is I set it with a nice drip and I leave and come back and it is not dripping any more. If I open up the ball valve more the bowl overflows because I had to much flow. It is very hard to get the right flow. Then I think I get it and the next batch does the same thing. Or opposite do I need a locking ball valve.

I think the main problem is that you are relying on gravity to provide a constant pressure to your valve. As the level in the tank gets lower the pressure decreases. You may need to add a small pressure regulated pump to provide a constant pressure to the valve.

This should also solve a problem which can occurr if you are drawing directly from a tank in which the wvo has been allowed to settle. The viscosity of the wvo can vary significantly (from top to bottom) and so the volume that flows through the valve can vary significantly as well.

To achieve dependable and predicatable filtration and water reduction of wvo from a centrifuge the wvo input must be standardized to a constant flow, viscosity, temperature, and particulate and water content.

The centrifugal processing units that most of my clients use are fed by a pressure regulated pump from a heated tank in which the wvo is constantly circulated. This in turn is fed wvo from settling tanks using a floating "outlet". All of this is to allow the wvo supplied to the centrifuge to be of as consistant as possible so the wvo stream from the centrifuge is consistantly under 300ppm water content.

The output is tested on a regular basis for water content and if a water level of higher than 300ppm is detected the wvo flow to the centrifuge is reduced accordingly. I evey case I have found that if a serious effor ti smade to reduce the water content to 300ppm the particulate content of the resulting fuel is as low (or lower) than average diesel fuel.


I know..more info than you requested..but I hope some of it helps you fix your problem.

Simple valves do not work for regulating flow, except in the case of very clean, consistant oil that is held at a constant temperature. Pumps are the usual means to regulate flow, but pumps for very low flow rates are hard to find. I've made my own, but there are some pretty easy ways to modify a standard pump to flow really slow. If your oil has been filtered to some extent, then a pump from an oil furnace will work, if a motor and pulley system is used that turns it slowly. Even hydraulic pumps can do the same job, driven the same way. I've read of people using windshield wiper motors to move a piston pump, relying on reduced voltage to slow it down. I've had moderate success using an electric automotive fuel pump (Facet, Carter, etc). I've also considered using a mechanical diaphram fuel pump (the kind with an arm that is worked by the camshaft) and a low rpm motor that pumps the lever once per revolution.

I've also read of people using an aquarium air pump to pressurize a drum to force oil out, regulating the oil flow by venting the air through a needle valve. Regulating air pressure this way works better than trying to regulate oil flow.

It's an interesting challenge.
Good luck,
JohnO

quote:

Pumps are the usual means to regulate flow, but pumps for very low flow rates are hard to find.

Pressure regulated pumps...like many electric fuel pumps..with a valve "downstrem" seem to be the simplest option here. The pump provides fairly constant pressure to the valve..which limites the flow rate.

Of course you have to have "fairly" clean wvo to send through the pump or it will will foul.

Gravity feed should be enough, I don't think you need a pump up there. Use large hoses from the top tank outlet right up to the point you wanted controlled flow, as near as possible to the CF input. Maybe put the control valve right on the CF? Keep the top tank full to the brim, for lots of head pressure. Maybe use a bigger top tank. Ensure the top tank outlet is well above the CF input.

What I'm finding as weather cools, viscosity is thickening and slowing the flow. Yes, a pump would also solve this problem. But I'm thinking I'll just heat the top tank for a day with a warmer, before CF'ing the load.

I have a pre-heater on the CF to raise the input temp to 150F. Warm oil cleans faster / better. This is thermostatically controller (with a PID controller actually), so as the flow changes due to head pressure or whatever, I'm not in danger of over-heating. It is easy to supply too much flow to the CF, such that the 1500W heater cannot even reach 150F, so I'm more concerned on slowing flow.

Here's my setup just for the heck of it..

I use a Raw Power CF.
I bought a 1/3hp 1 phase 120VAC motor locally for less than $150, from Baldor.
I bought a PID controller from Auber instruments, and a NPT fitting thermo-probe threaded into a homemade in-line heater using black iron pipe fittings, with a hot water heater element about 8 inches long inside it. I think it’s a 1500Watt element, 120VAC.
The inline heater is up-flow and is strapped to one leg of the CF.
I connect the inline heater to CF with about 18” of farm grade heat capable utility hose that fits on ¾” NPT barb on the CF. This hose allows flexibility to get the lid off CF for cleaning.
I have a plastic 55 gal drum sitting on top of a 275 gal tote and use gravity feed.
Drum has a garden spigot tapped at the bottom.
I use an industrial grade hose with garden host connectors to ¾” NPT barb on my inline heater.
My CF is raised up on a table so the rotor is just below bottom of drum height.
CF is bolted to table. Table is moveable on floor.
The CF output goes into the tote “backward” at the discharge point at the bottom of the tote.
Tote has a shutoff valve down there, and I normally leave it shut to prevent flood disasters when I’m not actively cleaning or filling from that tank.
I am thinking I need to add a heater wrap around my top tank and a blanket for the winter months so I can heat the dirty and get it less viscous, because flows are slowing as temperature drops.
I’m not too worried about wrapping the plastic tank, so long as its full of oil, don’t think there is any melting issues.
This is my first winter for the rig, it sits in my attached but unheated garage.
My setup takes about 4’ x 6’ floor space, and is about 7’ tall and needs a couple more feet of space above that, when I pour in the dirty. I have a ladder then stand on top of the tote, and pour into the drum.
I pour it through a sock filter 100micron just to catch the crumbs. So I cut a 6” hole in the top of the drum to drop the filter sock in. I use the long filter sock, about 30” hangs well into the drum.
I have a 2nd tote for dirty, and a hefty gear pump that I’ll soon be using to pump up to my drum, replacing the ladder and need for me getting up there. All of this gear fits between bay 2 and bay 3 of my garage, so I actually have 3 cars in there… but your space my differ. I am also lucky to have a 12 foot high garage ceiling.
My guy friends envy my garage, and almost always comment on its space when they see it.. it’s more like a shop size.

I think I have an eye on the problem. I think the exit plumbing is clogging the flow out of the machine. I have a three way ball valve that leads to two different drums. I ran new pvc pipe and it drained the whole tank slowly and appears to be working. As gravity feed, I will run the same batch and see if it produces waste.

This message has been edited. Last edited by: maddasher,