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Coolant Filtration

Oil, Water and Synthetic


The Oberlin Filter delivers Ultra Clean Coolant


  • High performance media and depth filtration typically delivers less than 10 ppm solids above 10 microns

  • Lengthens coolant life 5-10 times

  • Filters have flow rates ranging from 15gpm - 2,000gpm

  • Optional, cleanable, semi-permanent belts available for certain applications

  • Better surface finish

  • Less wheel loading/burn

  • Better part size control

  • Less heat build up

  • Less tool wear

  • Dress wheels less

Filtered steel fines from bearing grinding application.

The Filtered solids automatically discharge in an extremely Dry Cake

  • Filter cakes over 90% solids by weight in typical steel grinding.

  • Discharges a dry cake with less coolant loss.

  • Oberlin’s thicker cakes trap far more metal fines then paper alone.  Greatly improving the cleanliness of the coolant.

Before and after filtration: Synthetic coolant in a steel grinding application 

Dry Filtered Solids



How the Oberlin Coolant Filter Works


The idea is to pass liquids contaminated with solids through media, trapping the unwanted solids in, then on, the media. The goal for the most economical filtration cost is to lengthen the filter’s cycle time. This maximizes the quantity of the unwanted solids per area of media to reduce media costs. Long cycles means the filtration process is working with fewer interruptions for media changes. This increases the capacity of a filter. Smaller filters cost less and take up less space than larger filters. As the unwanted solids build up on the media, the flow of the liquid is impeded. Unless the liquid is highly pressurized, the flow of the liquid through the filter will drop quickly and not satisfy the flow capacity required.


Oberlin filters pressurize the liquid by pumping it into a chamber whose only outlet is through the unwanted solids on the media. The pressure is limited only by the size of the pump, not by atmospheric pressure. 30-40 psi is typical of an Oberlin filter. This is about three to four times more pressure than gravity or vacuum filters can develop. The time it takes to reach 10 psi is much less than the time to reach 30-35 psi in many applications. 

Animation of Coolant Filtration Process



We have over 50 years experience filtering coolants: oil, water soluble emulsions, and pure synthetics.  Please call our sales department to discuss the flux rates, filter sizing and expected performance for your particular application.


Our application experience includes:

  • Gear grinding
  • Creep feed grinding
  • Surface grinding
  • Slot grinding
  • Tungsten carbide grinding
  • Honing
  • Machining systems
  • Piston ring grinding
  • Bearings: race, track and ball needle grinding
  • ID, OD, centerless grinding
  • Driveshaft, crankshaft, connecting rod grinding
  • Non-metallic countertops, fiberglass, phenolic resins, ceramics, powdered carbon grinding, sawing, sanding




Here are examples of the cake of filtered solids that builds up on the filter media as the dirty coolant passes through the filter.  As the cake builds, the dirty coolant has to pass through both the filter media and the cake.  This cake greatly increases the filter's ability to capture very small fines, in some cases down to 1 micron in size.  The use of pressure keeps the dirty coolant flowing through the filter for long filtration cycle times on the same section of media.  The Oberlin Filter can use up to 20 times less media than other filters.





Above Video:  Cakes of filtered solids being discharged in a central filtration system for grinding steel bearings.  This is a reusable belt filter.


Left Photos:  Examples of dry cakes of filtered metal fines and solids.

  • Filter
  • Tank with 2 compartments- clean and dirty    
    • Dirty side receives coolant from machine and holds the coolant until it is pumped thru the filter.
    • Clean side receives filtered coolant and holds it until it is pumped  back to grinder.
  • Filter Pump which pumps dirty coolant to filter
  • Clean pump(s) which return clean, chilled coolant to machine at desired flowrates and pressures.
  • Chiller which removes heat from coolant.
  • Optional Ancillary Equipment like automatic coolant addition, sumps to pump coolant to dirty tank from machine, tramp oil removal systems.

A Coolant Filtration System consists of a:

Model OPF-9MLP Coolant Filter

Oberlin Cleanable Belt Filter – “Paperless Filters”

When applicable, the Oberlin Filter can use a cleanable and reusable belt instead of disposable paper/media belt.  Our cleanable belt filters are extremely efficient in saving our customers in consumable costs. 


Process Illustration of Coolant Filter

Central Filtration Systems

If you do production grinding or honing and have multiple small metalworking fluid filters scattered throughout your shop then replacing all of those filters with one Oberlin Central filtration system is the cost effective choice.
Centralized Oberlin Pressure Filtration systems maximize savings, increase available floor space and minimize labor costs by providing a single point for fluid management and solids disposal.

Oberlin Filter Company makes fully automatic coolant filtration systems ranging from 20 gpm to 6,000gpm. These systems are designed to support a single machine like a gear grinder, or an entire shop. The larger, central systems will usually have sumps at each machine to pump back dirty coolant to the dirty tank. The larger systems also tend to have redundant filter pumps and clean pumps to minimize downtime. The Oberlin Filter is simple in design resulting in a reliable uptime availability range of 99%. A large portion of our customer base are repeat customers which speaks for itself in regards to Oberlin's Filter users expecting the performance and reliability of our filtration systems.


We will customize the design to fit your space requirements. We will use your preferred PLC’s and screens. Or you can use our standard designs and controls for more cost effective packages.


Large Central 500-6000 gpm systems
Animation of Central System

Oberlin Tubular Filter

Oberlin Tubular Filter


In some situations the coolant doesn’t filter easily. For example, honing may only filter at a flux rate of 3 gpm/ft2. If many hones are involved, a large filtration area will be needed. In these cases we may recommend a tubular or candle type filter. It is a pressure filter also, but the filtering surface is on the outside of wire mesh tubes hanging vertically in a vessel. Hundreds of tubes can be contained in one vessel resulting in hundreds of square feet of filtering area. These tubes are usually precoated with a filter aid. The tubes are cleaned by backflushing with clean coolant. The system consists of a tubular filter, tanks for both precoat, backwash, dirty coolant and clean coolant, and an Oberlin Pressure Filter to dewater the backwash.


Some plants will not allow the use of silica based filter aids like Diatomaceous Earth (DE) However, recently fresh water based DE is available which does not contain any free silica and is non-hazardous.

Animation of Tubular Filtration Process

Ancillary Equipment


These ancillary system components will be fully integrated into the system controls.


  • Chillers: Air cooled, water cooled, remote condensers, submersible coil

  • Heat Exchangers using existing chilled water

  • Automatic Coolant Makeup- add coolant as required to maintain levels

  • Blend neat water soluble coolants with water to desired concentration

  • Tramp oil removal systems



  • Custom Engineered.

  • Flat bottom, sloped bottom, cone shaped.

  • Circular, rectangular.

  • Electrically controlled.

  • Pneumatic backups available.

  • Interfaces to grinder to: power up/shutoff; alarm; status

  • Overflow alarms standard: high level alert to grinder followed by time delayed coolant shutoff

  • Can include High Pressure supply pumps to reduce length of plumbing runs with pressurized coolant

  • Can integrate with hydraulic cooling using heat exchangers

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