Lubricants for Hard and Soft water

Lubrication and cooling fluids for industrial processes need to function in a variety of different settings. As we’ve covered, a great deal of effort goes into developing fluids to perform at very high temperatures for example. What’s also required of such fluids is that they can fulfil their function in both hard and soft water, so here’s what’s going on with the different water types and a look at some of the problems they can cause.

Whilst some industries have centred themselves around areas with hard or soft water, such as the brewing industry or the wool industry in the 18th and 19th century, the dispersion of different industrial settings in which fluids are used means that a concentration of manufacturing or processing plants around areas with favourable water conditions hasn’t been possible. Nor is it a realistic solution to use water imported from ‘alien’ sites with preferable water, because the volume of water needed in a constant flow means that mains connection need to be used, rather than water from storage tanks.


What are the Issues with Hard Water?

The hardness (or indeed softness) of water, is measured in parts per million or ppm. Ideally for lubrication purposes, these will be around the 90 ppm mark. If the level of water hardness is significantly higher than this then the performance of the fluids with which they’re mixed will dip noticeably. Between 200 and 300 ppm these fluids will stop functioning effectively within the process for which they’re developed, unless of course they’re specially designed to be able to cope with these conditions. This drop in the performance of lubricating fluids is largely down to the minerals which are present in hard water to a higher degree, reacting with the emulsifying agents in the lubricating fluid, and causing instability.

These emulsifiers are used to incorporate lubricants, oil or synthetic into the flow of water. If this process doesn’t occur stably then the movement of the fluid through the machining process can’t occur successfully and the fluid doesn’t fulfil its function properly, be it lubrication or coolant.
Hard water also develops a ‘scum’ in the same way that domestic chemical products do. The levels of magnesium and calcium in hard water causes this waxy substance to form.


Soft Water Lubricants

Inversely however, because of the absence of these minerals in soft water, excess lathering and foaming can also reduce the impact of lubrication and coolant fluids. Because these different water conditions cause contrasting issues, different grades of fluid for hard water and soft water have needed to be developed by the industry, so ensure that the fluid that you source is suitable for the type of water that will be flowing through your system.