WTF! Way Too Frigid. Another acronym using these same letters would also describe our recent weather, but this is a family blog. This winter is one the entire continent has been touched by, and even normally mild southern states have not been spared the wrath of arctic vortices, a word I hadn’t heard until it became appropriate to describe this year's weather in a unique way … and I’m Canadian!
Hydraulics and pneumatics don’t like ridiculously cold weather. Mobile machines using both hydraulic and pneumatic actuators are especially susceptible to the side effects of tundra temperatures. The reasons hydraulics don’t work well in the cold are different from the reasons for pneumatics, but as long as some foresight is applied, you should be okay.
Hydraulic fluid is the most critical aspect to consider, ensuring your machine will operate – and just as importantly; start working – when it drops to twenty below. A high quality multi-grade fluid with high viscosity index is important even in temperate climes, but unless the components and plumbing on your machine are significantly oversized, it won’t be enough.
Crazy cold requires a crazy hydraulic fluid, and the market has recognized this. Most hydraulic oil manufacturers offer some sort of “arctic blue” type fluid which starts out with a low weight (think like, 12 cSt), and also has impressive viscosity index (the index to reflect an oil’s ability to maintain its test viscosity over extreme cold and heat). This type of oil will prevent the need to start and run machines while they heat up, which wastes both time and money. It should be considered, however, arctic oil may not be the best oil when things get hot, so a summer change-out may be required.
Although air doesn’t freeze, one of the properties of air requires us to think twice. Air contains some water in the form of humidity. Just like humid air can freeze on your windshield, requiring you to risk frostbite to scrap it off, so too the humidity can freeze inside of a pneumatic circuit. It can also pool up as water during operation, and then freeze when the machine is shut down. Frozen water can damage seals or other soft parts of a pneumatic system, but at best, it will block the air line, often requiring cycling to heat the blockage or push it out.
Freezing can be prevented, of course, with air dryers. Dryers can reduce the humidity of the compressed air, and are common in industrial applications, but less so in mobile applications. Sophisticated electric dryers aren’t required, but an inline desiccant dryer will do the trick. Additionally, air filters are often available with water separators, a great last line of defence to liquid water.
If all else fails, and your mobile machine is simply frozen, just take the day off and curl up with an old issue of Hydraulics & Pneumatics.