When sourcing a piece of hydraulic equipment, there are 5 things about the environment the machine will operate in, that you should always disclose to the equipment supplier or designer–even if they don’t ask. Especially if they don’t ask:
1. Minimum and maximum ambient temperature. This information is necessary to determine the correct hydraulic fluid type, viscosity grade and viscosity index. Together with hydraulic fluid selection, it also determines whether tank heating is necessary at minimum ambient temperature (cold start). At the other end of the scale, maximum ambient temperature influences required cooling capacity.
2. Average humidity conditions. Locations where average humidity is high, for example tropical and marine environments, mandate the use of desiccant (moisture adsorbing) tank breathers and possibly, polymeric filters to limit water content to no more than the oil’s saturation level.
3. Airborne contamination/dust level. High dirt environments warrant extra consideration with respect to contamination exclusion and control. This could mean the deployment of a sealed and pressurized reservoir, or a vented reservoir with a bladder which acts as an impregnable barrier between the air in the tank and the oil. Cylinder-rod wiper seal arrangement is another area for scrutiny, along with the possible installation of cylinder-rod shrouds. And given that if you can’t exclude it, you’ve gotta remove it, permanently installed offline filtration may be mandatory rather than optional.
4. Altitude. Height above sea level and resulting reduction in atmospheric pressure affects pump inlet conditions-especially if the pump is mounted on top of the tank and therefore has to ‘lift’ fluid into its inlet (which is NEVER a good idea-even at sea level). If the pump has a flooded inlet (‘head’ of oil above the pump), the amount of head is easily adjusted to compensate for altitude at the design stage. Altitude also reduces the mass of air passing through an air-oil heat exchanger, all other things equal. Again, something which is easily compensated for at the design stage, if known.
5. Special conditions. For example, compliance with international, federal, state, local/municipal standards or codes; hazardous location; presence of ignition source (fire risk); environmentally sensitive (high pollution spill risk); etc.
No, they’re not rocket science. But if these 5 variables aren’t clarified at the outset, maintenance and reliability headaches are highly likely after the machine gets delivered. And to discover six other costly mistakes you want to be sure to avoid with your hydraulic equipment, get “Six Costly Mistakes Most Hydraulics Users Make… And How You Can Avoid Them!” available for FREE download here.