Machine Coolant Tanks

Ozone can successfully be used to eliminate bacteria and fungus (odor) from metalworking machine coolant tanks. The use of ozone will eliminate odors, reduce maintenance from biofilms (Slime) and prolong the life of machine coolant liquid, saving you money!

The problem:

Metalworking machines use a coolant fluid to cool and lubricate the process. This coolant is kept in a coolant tank and circulated through the machine and metalworking process as required. Over time, bacteria from the air, and machined products builds up in the coolant tank and causes foul odors along with biofilm build-up that may plug filters, screens, and pumps.

Coolant is commonly replaced due only to the build-up of bacteria in the coolant tank rather than the inability of the coolant to perform as a proper coolant and lubricant. There are costs associated with replacing the coolant for disposal, labor and replacement coolant.

The ozone solution:

Ozone is generated as a gas from oxygen found within the air via corona discharge. Ozone gas, in an air-stream can be bubbled into the coolant tank via a fine pore bubble diffuser. Larger coolant tanks may use multiple diffusers. Ozone will dissolve into the coolant and eliminate bacteria within the coolant. Due to the inherent inefficiencies of ozone generated from air and bubbled into water there is limited concern with ozone degrading the coolant itself over time.

The use of ozone will prolong the life of your coolant, while reducing odor and bio-films from the coolant.

Ozone equipment necessary:

The drawing below shows the equipment used and the method of installation into a machining coolant tank.

- Compressed Air – Typically provided from on-site compressed air supply.
- Solenoid Valve – or manual ball valve to start/stop airflow to the ozone generator.
- Air Filter/Dryer – May be needed if supplied compressed air is not sufficiently dry, or is not clean. Air should be dried with an upstream air-dryer and filtered after the air compressor.
- Pressure Regulator – will regulate both air pressure and flow to the ozone generator. Air pressures below 5 PSI will be used. Adjust the pressure regulator flow by visually indicating air bubbles from the diffuser in the coolant tank.
- Ozone Generator – will produce ozone from the oxygen within the compressed air stream. Options for ozone generators are listed below.
- Ozone Tubing – Ozone is highly reactive therefore either FEP or Stainless Steel tubing should be used for plumbing ozone gas to the tank.
- Check Valve – to ensure liquid cannot flow backward toward the ozone generator. If the ozone generator is sufficiently above the coolant tank this many not be necessary
- Diffusers – Break up air and ozone gas into tiny bubbles to better dissolve ozone gas into the liquid.

Ozone equipment suggestions/sizing:

Larger coolant tanks require more ozone and larger ozone generators. However, any ozone generator can be turned “down” to a lower ozone output and be used on a smaller tank. Below are a few general guidelines to use to select the right ozone generator along with ozone generator sizes.

- 500 gallon and smaller
  - HTU-500 Ozone Generator
  - SS2 Diffuser
  - FEP-250x375 tubing
  - CHK-4B check valve (if required)

- 500 - 2,000 gallon tanks
  - VMUS-4 Ozone Generator
  - SS2 Diffuser
  - FEP-250x375 tubing
  - CHK-4B check valve (if required)

- 2,000 - 5,000 gallon tanks
  - VMUS-10 Ozone Generator
  - SS2 Diffuser
  - FEP-250x375 tubing
  - CHK-4B check valve (if required)

Use one diffuser for every 12 square feet of tank surface area. If more diffusers are required, use a Tee fitting to connect the tubing to each. These are available HERE.

Suitable Air Filter if required