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Machine Coolant Filter Units Owners Manual

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Machine Coolant Filter Units Owners Manual

Owner’s Manual

CP 2002 (also CP 2002 Wall Mount) & CP 2020 machine coolant Filtering Systems 


In order to fit your new Filter System in the shipping container, it was necessary to disconnect the hoses and move the hose fittings. Before using your system, be sure to return these fittings to the upright (vertical) position, and then re-attach the loose three - way valve in place. 

Filter Housings

When tightening the filter housings, be sure to apply equal torque to both sides to minimize the possibility of  leaking. And please make sure the rubber 0-rings are snug and in the correct position. 

Easy Prime

Your filter system has been equipped with a new easy-to-prime feature. Simply unscrew the small white plug to the left of the pump. Add water, replace and tighten the plug. This procedure will only be necessary on start-up, or if your system should somehow lose it's prime. 

Replacement Filters

There are huge differences in filter life and filter effectiveness even in filters with the same ratings. To be sure of getting the right filters please order genuine Carbide Processors, Inc. replacement filters from your distributor. 

A long period of disuse.

If you turn off your system for an extended period of time (holiday week-end, vacation, etc.) we strongly recommend that you flush your pump and hoses with plain water. Occasionally, particles left in the system can harden and make the pump difficult to operate. 

If you experience any problems whatsoever, don't hesitate to call us your supplier or call us directly. (Carbide Processors, Inc. 800 346-8274). We stand behind our products, and will assist in any way we can. 

Thank you for purchasing our Filter System, we know it will prove to be a valuable addition to your shop.

Although this system was designed and built to be extremely safe, due to varying conditions under which this system might be used the manufacturer or its agents or distributors cannot be held liable personally or as a business for any damage or harm that might result from any use or mis-use of this system in any way. 

It is the responsibility of the user to see that this system is used safely and legally. If you cannot use this system safely and legally then you should not use it at all. 


Pressure gauge

(CP 2002 only, the CP 2000 does not come with a pressure gauge.) 

Find the pressure gauge. It is in separate box to protect it during shipping. It is packed between the tops of the filter housings but may shift during shipping. 



Remove the white plug and screw in the pressure gauge using Teflon tape or something similar to get a good seal. 

Filter Change Procedure

To change cartridge filters first release the pressure in the housing. The big blue units have a pressure valve and drain in the bag unit to relieve pressure. Then use the provided wrench to loosen the filter housing. 

Big Blue filters

1. Open the valve in the bottom of the bag filter housing and allow it to drain. 

2. Use the provided wrench to unscrew the housing.

NOTE: When opening filter housing to change cartridge or bag, it is common for O-ring / Gasket to lift out of housing and stick to cap. Do not lose the gasket (also called an "O" ring) 

3. Remove O-ring/Gasket from sump and wipe groove and O-ring/Gasket clean.

Lubricate O-ring/ Gasket with a coating of clean petroleum jelly (Vaseline). Place O-ring/Gasket back in place and press O-ring down into the groove with two fingers (or place gasket on rim of sump). 

NOTE: This step is important to ensure proper filter seal. Make sure the 0-ring is seated level in the groove (or gasket is on rim of sump). If O-ring / Gasket appears damaged or crimped it should be replaced at this time. See your local dealer for replacement parts. 

4. Take out the used bag filter and insert a new one.

If you are using activated carbon in your bag then add it here. 

Warning: The bag filter needs to be suspended in a mesh basket. Occasionally this basket gets thrown away. Inspect this basket. If it is bent the bag will not seal tightly and it needs to be replaced. 

5. Follow the same procedure to remove and replace the cartridge filter. Insert a new cartridge into the sump making sure that it slips down over the sump standpipe. 

6. Use the wrench provided to tighten the housing and then shut the drain valve. 

7. Screw the sump onto the cap and hand tighten. DO NOT OVER-TIGHTEN. Make sure cartridge slips over the cap standpipe. Make sure the filter housing is back and tight and the "O" ring is in place before restarting the system. 

NOTE: This replacement cartridge has a limited service life. Changes in taste, color and flow of the water being filtered are signals that replacement of the cartridge is or soon may be necessary.

CAUTION: Filter must be protected against freezing. Failure to do so may result in cracking of the filter and water leakage. 

CP 2020

The CP 2020 uses two 10” filter connected with a nylon disk. The nylon disk is reusable. Do not throw it away. 




When to Change Filters

Changing the filter too soon is a problem we run into in really good filing rooms. The guys who are good want to keep everything running well and they get concerned when things slow down. 

With the CP units we used a counter-intuitive engineering approach to get excellent cleaning with long (one month) filter life. Good filers get concerned when the speed drops off because that is what they would do if the performance of a saw grinder or a saw started slowing down. 

The CP units are different because these filters work better once they are a little dirty. 

The flow drops like a rock at first. Then it really starts working at the lower flow. Think of a Caterpillar tractor. It goes fast to the job but once it is there it puts the blade down and starts shoving dirt. It runs a lot slower once it is shoving dirt but that is what it is supposed to do. 

Both the CP systems and Cat tractors have big motors not to make them go fast but so they can do a lot of hard work at lower speeds. Changing the CP filters when the flow starts to slow down is like a cat skinner that quits pushing when the speed starts to fall off. Changing these filters too soon is like backing up and running at a pile of dirt instead of steady pushing. These are long life filters.

10 to 25 psi. is normal operating range

Pressure about 5 psi (under 10 psi) with new filters

At 25 psi. change filters 


When to change the filters

We recommend changing the filters when; 

1. The machine coolant is dirty using the one bottle test

2. The flow is less than 50 gallons per hour

3. The pressure is at or over 25 pounds on the pressure gauge

10 to 25 psi. is normal operating range. This is a long –life, high-pressure filter system. As the pressure goes up the unit works better. As the pressure goes up, the flow goes down but the machine coolant actually gets cleaner. 

Did the filters need changing?
The bag filter will hold:

  1. 4.5 pounds dry weight of swarf (about 5.5 # wet)

  2. There can be a layer 5 inches deep on the bottom

  3. There can be a coat as much as 3/4 of an inch thick all around the sides from top to bottom

If you changed the filter and it was not this dirty then you changed it sooner than you needed to change it. 



Common concerns

1. As the unit works better and longer the flow gets slower. This is often seen as a problem and most often it is not a problem. See the section below on fluid flow. 

2. Originally the machine coolant comes out clean but then it gets dirty. This is like oil in a car. New oil looks dirty very soon but it still keeps working very well. Filtering takes out the big particles. The very small particles do not do damage but they can color the machine coolant. See the section on particle counts. 

3. Short filter life. See the section on the most common reasons for short filter life.

The filter system is supposed to keep the machine coolant clean. As long as it is keeping the machine coolant clean the filters do not need to be changed. The number one cause of low filter life is changing the filter too soon. 

The CP 2002 uses three-stage filtering. In stage one the flow rate really drops. A good operator will notice this and want to change the filter because the flow looks so slow compared to new filters. Do not change the filters here. Change the filters when they are no longer cleaning the machine coolant. 

The way the machine coolant looks

A new filter will clean the machine coolant so it looks clear and clean. There is a dramatic change. After a couple days the machine coolant will have a dirtier look to it. The filter system pulls out 98% of all particles. It is most likely to miss the very small particles. It only takes a little bit of the very small particles to make the machine coolant look dark. 

This is like oil in a car. Oil that is a couple days old does not look new but it is still good for months because it is filtered. 

The test here is to fill a clear bottle with machine coolant. Let it sit. There is normally a thin layer of fine particles on the bottom. In dirty machine coolant the bottle can be as much as one-third full of particles.

(See "one bottle test information" please.) 

The flow rate

A new filter will have a flow rate of 800 gallons per hour. After a week the flow rate will be about 300 to 400 gallons per hour. The filter system is working as long as it is filtering the whole sump at least twice per hour. In a fifteen-gallon sump it will fill a gallon bottle in 2 minutes and a pint bottle in fifteen seconds. 

This is deceiving. A new filter will look like a garden hose on full. A filter that has been in a while will look more like a drinking fountain. 

Three tests

  1. Fill a clear bottle with machine coolant. Let it sit. There should be a light layer of fine particles on the bottom.

  2. Measure the flow. The flow can be very slow and still be cycling the entire sump twice an hour.

  3. The filter bag should be really dirty. It should have a layer around it that varies from one half inch thick to three-quarters inch thick.

Is the unit cleaning the machine coolant?  

One Bottle Test Information

  • Take a clear glass bottle.

  • Fill it out of the end of the hose

  • Let it sit one hour.

At the worst, the machine coolant should be clear with a light layer of sediment covering the bottom

Note: Change the filter if there is an oil or grease layer 

How to analyze the bottle of machine coolant

You may see some settling in fifteen minutes. If the machine coolant is very clean it may take two hours or more to get anything to settle out. The best length of time would be to let the bottle sit for twenty-four hours. New machine coolant will clean with no sludge layer, no oil layer and no reddish color. 

Test 1. Fill any clear bottle or jar most of the way to top with grinding machine coolant. This is not a critical measurement. Label it with the time and source.

It might be a good idea to label the samples with the date, the machine, type of machine coolant, time since last machine coolant change and anything else important. 

Test 2. How long does it take for particles to settle out?

See how long it takes for the particles to settle to the bottom. The finer the particles are the longer it will take to settle. Dust will float on top of and in water. Rocks will drop right to the bottom. This will give you some idea of particle size. If you get a thick layer immediately and nothing later then it is probably all particles over ten microns. If you do not get anything on the bottom in the first minute and the sludge layer grows over a day then you probably have particles that are all under two or three microns. 

Typically you will get a pretty good sludge layer starting in a few minutes. That layer will continue to grow for up to an hour. After an hour it should be pretty well all settled out however the really fine particles may take up to day to settle out. 

Test 3. Measure the amount of sludge

Once everything has settled out measure the height of the particle layer on the bottom. A three-inch machine coolant sample can settle out to have as much as an inch or more of sludge on the bottom. The thicker the sludge layer the more sludge there is. 

Test 4. Check the top for an oily layer. Looking will tell you if you have tramp oils in your machine coolant. This is really simple but it is also very important. Oils and greases really clog filters and grinding wheels. Some machine coolants could be disposed of in sewers except for the oils and greases. 

Test 5. Check the color of the machine coolant.

This is a test for metal contamination of the machine coolant

In a lot of machine coolants the dissolved cobalt will cause a color change and a reddish or purplish tint. The amount of color change is related to the amount of dissolved cobalt. 

Test 6. Cobalt levels and conductivity

The amount of color change relates to the change in conductivity of the machine coolant. This is important if it is being sprayed in sensitive areas. The amount of color change relates to the amount of chelated (sort of like dissolved) metals in the machine coolant. Test conductivity with a meter. Other factors effect it besides dissolved or chelated metals. 

Test 7. Look at the machine coolant.

If you see things floating in the middle of the machine coolant you may have fungal or bacteria growth. 

Test 8. Shake the bottle

Once the sludge has settled out, shake the bottle and try to get the sludge back into suspension. A. This will give you an idea of how much sludge there is in relation to the ability of the machine coolant to carry sludge. B. You will also get an idea of the amount of oiliness by how well the sludge sticks to the walls of the bottle. Typically it will be impossible to shake the bottle enough to get all the sludge back into suspension. 

Flow rate

The unit should be circulating enough to filter the whole sump every hour. This can be hard to judge by eye because we use a big pump and a three-stage filter. The unit has a big flow at the start. At the end of one week the flow is only about 1/15 ( 7% ) of the initial flow. This is still about 90 to 150 gallons per hour. This will clean a 30-gallon sump three times and hour and a 10-gallon sump about ten times an hour.



Initial flow rate will be strong like a garden hose.

This is the flow rate after 30 days.

When to change filters - Time to fill bottle 

Sump size

1 gallon bottle

1 pt. (16oz.) bottle

30 gallons

2 minutes

15 seconds


3 minutes

22 seconds


6 minutes

45 seconds


12 minutes

90 seconds

The filters for the CP 2002 are depth filters. They are designed to work in three stages. Stage one is the outer filter. In this case you see a dramatic drop in flow rate in the first week. Then stage two kicks in and you see a very slow drop in flow rate in weeks two and three. About week four the third stage kicks in and the flow rate climbs a little and then stabilizes. Many people see the drop in flow in stage one and change the filters. Stage three actually filters best. 

This is the flow rate by days.

Filter Performance  


Stage One

Stage Two

Stage Three

Flow rate at start

30 gal. / min.

5 gal. / min.

2 gal. / min.

Flow rate at end

5 gal. / min.

2 gal. / min

3 gal. / min.

Typical particle count





Flow rate by days ( 30 days dbl shifts)

The first number is the pump without filters. The flow drops dramatically once the filters are inserted. Phase one is the steep drop in about the first week (these are double shift days shown here so about 4 days here). Stage two is the more gradual drop. Stage three is the steady stage where the flow actually recovers a bit. Stage 3 actually filters best. Many people see the drop in flow in stage 1 and change the filters. (In days 25 and 29 no measurement was taken) 

The CP 2002 filters very well through all three stages. The left diagram shows the comparison with an unfiltered sump. The unfiltered sump has about 75,000,000 to 100,000,000 particles per cubic centimeter of machine coolant. The comparison figures from the filtered sumps are in the range of 45,000 to 500,000 so they do not show up in the left graph. The right graph shows the comparison of the particle counts in the filtered sump. Even the 500,000 at three months is just 1 / 150 of what would be in a dirty sump.



Reasons for Short Filter Life 
1.  Changing the filter too soon because:
     A. The way the machine coolant looks
     B. The flow rate
2. Using the Wrong filters
3. Use the system on more than one machine
4. Too much oil and grease
5. Heavy grinding
6. Hose Placement
7. Clogged Intake Screen
8. Only filtering once a week


1. Changing the filter too soon.
We designed this system to give long filter life. We picked a filter that takes a couple days to settle in. As the filter gets loaded a little over the first couple days the flow drops off but the filter actually gets more efficient. The machine coolant is cleaner after 22 days than after one-half hour or eleven days.

A. The way the machine coolant looks
A new filter will clean the machine coolant so it looks clear and clean. There is a dramatic change. After a couple days the machine coolant will have a dirtier look to it. This is like oil in a car. Oil that is a couple days old does not look new but it is still good for months because it is filtered.

B. The flow rate
This can be deceiving. A new filter will look like a garden hose on full. A filter that has been in a while will look more like a drinking fountain but still be working fine.

2. Using the Wrong filters
The heart of the whole system is the filter. Lately we have had complaints about short filter life. It turns out the customer was just buying any filter from whoever was handy. This is like putting just any fuel in a car. If you put diesel or kerosene in a car that needs unleaded gas you will get big problems.

3. Use the system on more than one machine.
Our filter life tests were done on one machine being filtered constantly. Two machines will generate twice as much material so filter life will be half as long.

If you use the filter system one-hour a day on each machine you will remove 98% or better of all the material generated during that day on that machine. Better than not filtering at all but not as good as constant filtering.

4. Too much oil and grease
All grinders leak a little oil, grease and hydraulic fluid. Oil and grease can cause the particles to form clumps and dramatically shorten filter life. The filter systems can handle a normal amount. Too much can dramatically shorten filter life.


This is a roll up filter used in a heavy grease environment. You can see where the outer layer was covered and nothing got through the grease clog.

5. Heavy grinding
We did calculations on an actual bag from a customer's operation that shows it ground the equivalent of 3,623 saws. This is taking 0.005” off each side. If you take off twice as much you can only grind 1,800 saws before you need to empty the filter. More tips means less saws. Smaller tips than half –inch means more saws and soon.

6. Hose Placement
This is a machine coolant-filtering unit. It is designed to filter out the particles suspended in the machine coolant. A lot of crud naturally falls to the bottom of the sump and stays there. If you put your hose on the bottom of the tank you will suck all this up and shorten filter life. If you put the hose near the top of the tank (maybe six inches down from the top) you will be filtering the machine coolant only and you will greatly extend filter life.

7. Clogged Intake Screen
The end of the intake hose has a screen on it to keep large chunks out of the pump. (The pump will handle particles as large as BB's but anything larger will jam it.) This screen can get coated with grease and sludge. The screen can be easily removed with a medium size, blade type screwdriver. The hose clamp is stainless steel so it will not rust. Remove the filter screen, back flush it and replace it.

8. Only filtering once a week
When we say it ran 22 days of double shifts that means it ran all the time on a single machine. It ran 352 hours without a filter change. The key element here is how much it filtered out. If you run the unit one-hour a week it will filter out the same amount as if you had run it for 80 hours week.

US government certified testing

If you send us a sample of your machine coolant we can have it tested for you. We need 16 ounces (about a pint) in a tightly sealed, clean bottle that will not break. The bottle has to be labeled with your name and the contents.

1. Particle size and count $60
2. Turbidity $30
3. Viscosity $30
4. pH $20
5. Conductivity $30
6. Cobalt levels $34



Possible cause

Corrective action

Filter housing leaks

" O" ring not seated

Close valve, Turn motor off, Relieve pressure, Drain housing, Remove and  inspect "O" ring. If good then lubricate and replace. Tighten until you feel the “O” ring compress.

Low machine coolant flow

May be normal

See "when to change the filter" Run "1 bottle test"

No machine coolant flow

1. Loss of prime
2. Clogged intake valve
3. Dirty filter
4. Intake valve removed

Unscrew and clean
Replace filter
Hose can suck shut against a flat surface - replace valve / screen

All rights reserved including all rights to reproduce any amount of this material in any form or for any purpose without specific permission.

For permission contact:
Thomas J. Walz
Northwest Research Institute, Inc. / Carbide Processors, Inc.
3847 S. Union Ave.
Tacoma, WA. 98409
253 476-1283