Metal working fluid decontamination apparatus

A method of decontaminating a metal working fluid comprising the steps of:

• providing a metal working fluid decontamination apparatus including:
• an intake arrangement for the metal working fluid;
• a pump for providing, in use, flow pressure to the metal working fluid;
• a decontaminator for reducing contamination in the metal working fluid;
• an outlet arrangement for the metal working fluid;
• the decontaminator comprises a filter arrangement, to reduce particulate contamination in the metal working fluid, wherein the filter arrangement comprises a microbial filter for filtering microbial particulates such as bacteria, and, wherein, the microbial filter is at least a 1.0 micron filter,
• the decontaminator comprises an ultraviolet (UV) light treatment arrangement which comprises a UV light source, the UV light treatment arrangement defines a treatment passage;
• wherein, the metal working fluid is a fully synthetic metal working fluid comprising water and a water soluble synthetic concentrate which does not contain oil, and wherein the metal working fluid is substantially transparent and in a fresh unused condition,
• operating the pump to draw the metal working fluid into the apparatus and provide flow pressure to move the metal working fluid through the apparatus to the outlet arrangement via the decontaminator;
• and
• reducing contamination in the metal working fluid in the decontaminator including in flow sequence (i) filtering the metal working fluid in the filter arrangement to restore the transparency of the metal working fluid so that after filtration, the metal working fluid is substantially transparent, and (ii) treating the substantially transparent metal working fluid with UV light as it flows along the treatment passage of the UV light arrangement.