The Role of RPM and G-Force

RPM is a measurement of how many times the centrifuge bowl spins in one minute. The centrifugal force (g-force) generated by the spinning bowl is directly related to the size of the bowl and RPM. In the case of the Ultimate Force Centrifuge with a bowl diameter of 9.5 inches and operating at 3,450 RPM , which is 57.5 revolutions per second, the resulting g-force is 1,650 times the force of gravity. This force drives contaminants out of the oil and towards the walls of the centrifuge bowl, where they can be trapped and separated.

However, a common misconception is that higher RPMs always lead to cleaner oil. This is not necessarily true. While increasing RPM does enhance the centrifugal force, which can improve the separation of smaller particles, the design of the bowl and the flow rate of the oil are equally, if not more, important.

The Impact of Flow Rate on Oil Cleanliness

Flow rate significantly influences the time oil spends in the centrifuge bowl—known as the residence time. The longer the oil remains in the bowl, the more time the centrifugal force has to act on the particles, improving the separation efficiency, and leading to cleaner oil.

The Ultimate Force Centrifuge is capable of handling up to 30 gph. However, the cleanliness of the oil is inversely proportional to the flow rate. Running the centrifuge at the maximum flow rate will not provide the cleanest oil. For the best results, reducing the flow rate to 15 gph, 10 gph, or even 5 gph allows the oil to spend more time in the centrifuge, enhancing the removal of contaminants.

How the Oil Flows Through the Centrifuge

To understand the relationship between RPM, flow rate, and oil cleanliness, let’s look at the process of oil purification in the centrifuge bowl.

1. Oil Entry and Acceleration: Oil enters the bowl at the center and is directed to the bottom by an accelerator cone which is built into the bowl lid. This accelerator or booster cone distributes the oil by forcing it to the very bottom of the bowl subjecting it to the maximum centrifugal force.

2. Centrifugal Separation: As new oil enters, it pushes the existing oil upwards along the bowl’s walls. The centrifugal force causes heavier particles, contaminants, and water to travel toward the bowl walls, where they get trapped.

3. Oil Exit: The cleaned oil moves across the top of the bowl, reaching the 3 lid breeches. It escapes through the grooves in the lid, spraying upward and out towards the edge of the centrifuge housing. The cleaned oil then escapes through the clean oil drain and into a container.

4. Contaminant Collection: When the unit is turned off, the residual oil (approximately half a gallon) drains through holes at the bottom of the bowl, exiting through the dirty oil port. The debris and matter inside the bowl can then be cleaned out and it’s ready for another run. Depending on the type of oil and level of contamination, the centrifuge bowl only needs to be cleaned every 300 to 500 gallons of oil.

The Importance of Bowl Design

Bowl design is a key component that overshadows the benefits of high RPM. Like the Ultimate Force Centrifuge, a centrifuge with an enclosed bowl design promises contaminants are efficiently trapped and forces the oil to travel along the bowl lid before escaping. In addition, an accelerator or booster cone should be mandatory when selecting a centrifuge. This cone directs the oil to the very bottom of the bowl ensuring it completely travels under the infliction of G-force. When an accelerator cone is not present the oil enters the bowl and splashes entering the oil curve midstream, resulting in sub-par cleanliness results. The bowl design should also allow for effective draining and cleaning of the bowl, for convenience and ease of use.

Practical Recommendations for Optimal Oil Cleanliness

To maximize the efficiency of oil purification using a centrifuge, the following practices are recommended:

1. Optimize Flow Rate: While the centrifuge may handle up to 30 gph, running it at lower flow rates between 5 and 10 gph—significantly impacts oil cleanliness. The extended residence time allows the centrifugal force to more effectively separate contaminants.

2. Regular Maintenance: Periodically inspecting and cleaning the bowl is crucial. After turning off the unit, allow a few minutes for the oil to drain before opening the bowl. This prevents the reintroduction of contaminants into the oil supply and maintains the efficiency of the centrifuge.

3. Monitor Performance: Regularly check the quality of the output oil. Adjust the flow rate as needed to ensure optimal cleanliness. If the oil is not meeting cleanliness standards, consider reducing the flow rate further.

4. Consider Bowl Design: Choose centrifuges with well-designed, enclosed bowls. The design will efficiently trap contaminants and is easy to maintain.

In Summary

In summary, while RPM and g-force are impactful factors for the operation of a centrifuge, they do not solely determine the cleanliness of the oil. The flow rate of the oil and the design of the centrifuge bowl are equally important. It is advised to operate your centrifuge with a flow rate between 5 and 10 gph. The Ultimate Force Centrifuge with its enclosed bowl design and following our flow rate recommendations, will give you high-quality clean oil which can then be used for fuel in diesel engines.

When it comes to cleaning waste oil using a centrifuge, using an inline heater in your setup will make a significant difference. Typically, oil is heated within the range of 170°F to 200°F for optimal performance. However, the specific temperature at which the heater should be set depends on the flow rate of your oil. The quicker your flow rate the higher the temperature on the heater to adequately heat the oil. 

If you do not use a heater when processing waste motor oil it is highly recommended to dilute the viscosity of the oil with diesel. Never mix vegetable oil with diesel fuel, the two oils will separate and cause issues when using the fuel.

Here are the top reasons an inline oil heater should be used:

1. Better separation of contaminants: A heater enables the centrifuge to effectively capture debris in the oil, significantly boosting its efficiency in a single pass.

2. Increased production rate: By incorporating a heater, you can ramp up the rate at which you process oil, leading to improved efficiency overall.

3. Water content reduction: Heating the oil facilitates the evaporation of water content reducing the water content present in the oil.

Our inline heater is designed to bolt seamlessly to the leg of the centrifuge, offering both 120V and 240V options for your convenience. To optimize its performance, ensure that the oil is fed into the bottom port of the heater, with the output directed into the centrifuge at the top. This setup prevents the heater element from burning out as it remains consistently submerged in oil. Never use a hose from the heater feeding the centrifuge that is not rated for heat.

Integrating an inline heater into your oil centrifuge setup is a smart move. Not only does it improve debris capture efficiency and processing rates, but it also helps reduce water content, ensuring cleaner oil output for your operations. 

The Ultimate Force Centrifuge ships completely assembled with the exception of leg attachment, threading of fittings, and basic wiring.  If you purchased an inline heater, you will need to install it.  While every precaution has been taken to be sure your equipment arrives in perfect condition by packing with great care, handling and shipping is out of our control.  Upon its arrival, please inspect the package and report any obvious damage to us right away.

*Tools necessary:  4 mm, 5 mm, 8 mm, and 3/16” Allen wrenches 

SAFETY

As with all equipment, there are safety hazards involving oils, centrifuge use, static electricity, and piping of your unit and holding tank.

• Never operate the centrifuge without the cover securely attached.
• Never open a running centrifuge.
• Caution must be taken when centrifuging all flammable liquids.
• Ground all equipment before use to prevent static electricity.

It is the owners’ sole responsibility to decide what types of liquids are safe to centrifuge taking into consideration flammable vapors.

Unpacking 

When unpacking your centrifuge pull the unit out of the box and set aside on carpet or padded area so you do not scratch the lid.  Since the unit weighs approximately 65 lbs, caution should be used when removing it from the box. The packing peanuts are biodegradable and can be recycled or disposed in a sealed bag.

The Ultimate Force comes completely built except for the legs.  The legs are installed on the unit in reverse for ease of shipping.  Hold the top of the leg in place.  While using a 4 mm Allen wrench, remove the two screws on each leg.  Turn the legs around and reinstall.  You should be able to hold the leg in place and hand tighten both bolts.   When both bolts are in, using the Allen wrench, tighten both bolts again.  When the three legs are reversed, they will extend out from the unit as pictured.

120V Wiring

Consult the Wiring Diagram on the motor 

1. Identify the color-coded wires on the motor. The most common colors are black, white, brown, red, and green
2. Remove the black plastic cover on the side of the motor and install the wire clamp. Run your power cord through the connector.
3. Match the black wire on the motor to position 2 as in the photo.
4. On your 120V cord connect the Hot lead (Typically black) to position 1.
5. Match the white wire on the motor to position 4.
6. The white wire on the power cord is neutral, connect it to position 4 as well.
7. Connect the ground wire to the ground screw on the motor.
8. Use wire connectors or wire nuts to secure the connections.
9. Reinstall the motor cover plate.
10. Once all connections are made, turn on the power supply and test the motor.

240V Wiring

1.  The motor arrives with the three motor wires configured for 120V. The Brown, White, and Black wire will need to be disconnected.
2. Install the wire connector onto the motor side and run your power cord through the connector.
3. Match the Black and White wire to position 3.
4. Connect the brown wire to position 5 or “P” which may be plastic.
5. One of each hot wire from your power cord will be connected to a Hot Lead.
6. Connect the ground from the power cord to the motor ground screw.
7. Use wire connectors to install the wires to the proper position.
8. Reinstall the motor plate cover. 
9. Turn on the power supply to test the motor.

*Wiring may vary depending on the motor your unit has installed. Always consult the wiring diagram on the motor prior to testing.*

Setting up Attachments

Set your unit on a flat surface below the contaminated oil feed and above the container being used to catch the clean oil.  

The centrifuge comes with a vibration damper at the bottom of all three legs.  Each damper has two holes which are to be used to mount your centrifuge to a hard surface.

Recommendation:  Use a piece of plywood larger than your clean oil container.  Mount the plywood to the container ensuring that the equipment and plywood will not move.

The clean oil and contaminated oil drain both come with all fittings included.  The ¾” 90 and the ½ “ 90 will need their respective hose connection fittings installed as pictured below.  You will need to purchase ¾” hose for the clean oil drain and ½” hose for the contaminated oil drain.  The length of these hoses is dependent on the distance to your container. 

Your supply container should have a gate valve to control the oil flow and a ball valve to be used as a shutoff valve.  The flow will be dependent on temperature as well as the amount of oil in the container. As the temperature of the oil decreases, its viscosity increases, resulting in a slower flow. Additionally, as the oil level decreases within the container, the flow rate will also decrease.

The clean oil drain is ¾” and needs to have fittings attached to the bottom of the centrifuge as in the picture above on the left. Clean oil will drain during operation and will cease draining upon shutdown.

The contaminant oil drain is ½”.  Connect the fittings as pictured above on the right. The ½” hose from the contaminant side will only drain when shutting down the unit or when overflowing.

Feed to Centrifuge Attachment

The centrifuge comes with a 1/2” hose barb to introduce oil into it.  Make the connections from your dirty oil container to include a gate valve for adjusting flow, a ball valve as an on/off flow valve, ending with a ½” hose barb.  Connect the two hose barbs with ½” clear braided hose.

The oil entry fitting is a ½” hose barb, 90 and reduced down to a ¼” nipple.  Install the  ¼” nipple into the opening on top of the lid.  (This will be a tight fit due to o-rings in the opening.)  The lid has two breather caps for forced ventilation.

Heater Installation

When attaching the heater to the leg, first hand tighten one bolt through the bottom hole in the leg and into housing.  Then attach the heater using the top hole.  Place bolt through the top hole in the heater and centrifuge leg and into housing, then remove bottom bolt from leg and swing heater into place aligning bottom heater hole with leg hole.  Bolt together and tighten both bolts.

From your dirty oil container, run your ½ “ hose to the bottom hose barb on the heater.  Oil should always be introduced into the bottom of the heater and exit the top ensuring the heating element is always submerged.  Connect the top hose barb with the 400 degree F. hose to the ½” hose barb on the lid of the centrifuge.  NEVER use a hose from the heater feeding the centrifuge that is not rated for heat.  Place a  ¼ “ plug in the bottom of the heater. You are now set up and ready to turn your unit on. 

NOTE:  Always turn the centrifuge on first (you want the centrifuge on before you open the oil flow), and turn the centrifuge off last (you want the centrifuge running until you turn the oil flow off).  

Finishing the Centrifuge Run

After you have turned the centrifuge off, the bowl will quit spinning and will automatically drain  out of the dirty oil drain.  Do not remove the bowl from the unit until all oil has drained out.  This can be verified by checking the dirty oil drain hose.  

Bowl Removal

With an 8 mm allen wrench, hold the bowl steady and loosen the nut.  Turn counterclockwise to loosen the nut. Pull the bowl out of the housing and place it in a container to catch any residual oil left in the bowl.

Bowl Lid Removal

With a 4 mm Allen wrench, hold the bowl steady, loosen and remove six screws.

After removal of screws, lift the lid and turn counterclockwise approximately 1 ½” to release the locking lid.

The bowl does not necessarily need to be removed for each cleaning, as the bowl itself is self draining.  Once the bowl lid is removed, you can simply wipe out the bowl.

When replacing the bowl lid, ensure the seal is properly placed in the groove.  Make sure all bolts are tight.  Set bowl on bowl mount inside housing.  Holding with one hand, tighten the nut.

Once your bowl has been installed, check all bolts on the bowl lid and the bowl mount for tightness.  Make sure the seal for the housing is in the groove and install the housing lid.  Lock down the three latches.  You are now ready to start another run.

Disclaimer:

 Every effort has been made to ensure the accuracy and completeness of the instruction manual. However, PA Biodiesel Supply, a Division of Wheeler Inspirations LLC, makes no warranties, expressed or implied, regarding errors or omissions, nor will it be held liable for the use of this product or any adapted version of this product, and assumes no legal liability nor responsibility for loss or damage resulting from use of the information contained herein.