Hydraulic Fluids: Coolant and Power Source

Hydraulic mechanisms provide large amounts of power due to hydraulic fluids, which are pumped at extremely high pressure through motors and hydraulic cylinders. Hydraulic fluid is transported through a mechanism by tubes and hoses.
 

Hydraulic Fluid Use

Used in multiple systems, hydraulic fluids are common in vehicles' brakes and transmission systems. Backhoes rely on hydraulic fluids for power, and the crusher on the back of a garbage truck is usually hydraulically powered.
 
Hydraulic fluid fulfills a number of roles in addition to providing power to hydraulic engines. Hydrolytic fluid:
  • acts as a coolant
  • filters debris and impurities.
  • provides lubrication to hydraulic engine parts.

In general, hydraulic power is used when large amounts of power are required. Hydraulic fluids in roller coasters eliminate the need for the old gear and chain pulley that pulls the roller coaster cart up to the first drop. Instead, hydraulics in roller coasters provide enough power to launch passenger cars at high speeds right from the start of the ride.

Hydraulic Fluid and Transportation
Brake fluid is a common hydraulic fluid used by millions of drivers every day. Hydraulic fluid is also used in aircraft landing gear.

Types of Hydraulic Fluid

Hydraulic fluids don't fall neatly into one category.Even simple tap water can be a hydraulic fluid in the right circumstances.
 
The bulk of hydraulic fluid is either water- or mineral oil-based. Hydraulic fluids may also be made from any of the following bases:
  • castor oil
  • esters
  • ethers
  • glycol
  • organophosphate
  • propylene glycol
  • silicone.
For environmentally sensitive situations, canola oil also works as a good base for hydraulic fluid. Tractors and other hydraulic farm equipment often use canola oil-based hydraulic fluid to prevent environmental contamination.

Hydraulic Fluid Additives: Coolant and Antioxidizers

Like other forms of liquid lubrication, hydraulic fluid often contains additives. Coolant may be added to hydraulic fluid to keep machine parts from overheating. Other additives help filter out impurities and debris that would otherwise cause damage and wear.
 
Hydraulic fluid degrades over time when exposed to oxygen, a process that speeds up dramatically when traces of water, iron, copper, zinc or other metals contaminate the hydraulic fluid. To slow this process, many hydraulic fluids contain antioxidants.
 
Safety and Hydraulic Fluids
 
As with any type of lubricant, hydraulic fluids require that you practice a particular handling methods. Not following the suggested handling guidelines for hydraulic fluids can endanger you and/or those around you. Here are some handling guidelines associated with hydraulic fluid:
  • Never ingest hydraulic fluids, as it can result in fatality.
  • Wear gloves when handling hydraulic fluid, as contact with this lubricant can cause serious skin irritation.
It's also important to note that regular contact with hydraulic fluid over long periods of time is associated with hand weakness. Currently, the effect of breathing in hydraulic fluid on humans is unknown, but clinical tests have shown that inhaled hydraulic fluid causes nerve damage in animals.
 
In addition to it's potentially toxic properties, the high temperatures at which this lubricant often operates can also cause you harm. Consequently, you should be careful when working with hydraulic fluids.
 
Resources
 
Agency for Toxic Substances and Disease Registry. (updated September 2007). ToxFAQs for Hydraulic Fluids. Retrieved January 29, 2008, from the Agency for Toxic Substances and Disease Registry Web site: www.atsdr.cdc.gov/tfacts99.html.

Hydraulic Equipment and Tools Marketplace. (n.d.). Hydraulic Oil. Retrieved January 29, 2008, from the Hydraulic Equipment and Tools Marketplace Web site: www.hydraulic-equipment-manufacturers.com/hydraulic-oil.html.

Hydraulics and Pneumatics. (10 August 2007). Technology Zones. Retrieved January 29, 2008, from the Hydraulics and Pneumatics Web site: hydraulicspneumatics.com/200/FPE/Hydraulics/Article/
True/6449/Hydraulics.

Levine, A. (11 October 2007). Kingda Huh? Retrieved January 29, 2008, from the About.com Web site: themeparks.about.com/od/rollercoasterarticles/a/
KingdaHydraulic.htm.