hydraulic oil

Water works as a hydraulic fluid, but sealing it at hydraulic pressures is a problem.

To seal water at these pressures usually involves unacceptable friction losses.

Corrosion can also be a problem.

If hydraulic oil is contaminated, damage from corrosion is usually not far away.

Also, if I am not wrong, the water would expand or contract in volume based on ambient temperature. This leads to difference in output of hydraulic system. And ofcourse contamination is one of the major issues as discussed above.

Water it self can be used as a hydraulic fluid. As a replacement for oil depends on the system. As for a hydraulic press the viscosity of water would not allow the pump to produce the proper output pressure. Clearances in the pump are designed to the viscosity of the oil. As the water heats up from any where between 110°F to 180°F you would face cavitation problems. The low pressure on the suction side of the pump may cause the water to boil. So it would not be a good idea to mix the two.

Most parts of a hydraulic system are of steel so there will be corrosion issues. The oil also provides lubrication to the moving parts that water would lack.

Now if you are trying to design a system to use water. The cost to over come these issues would well out weigh the cost of using oil.

Check out these companies that are the major ones in High Pressure Water-Hydraulic systems:

http://www.elwoodcorp.com/fluid.htm#cartridge

http://www.elwoodcorp.com/395_PDF.pdf

http://www.huntvalve.com/index.htm

These companies make quipment capable of using Tap Water but these systems often use some Water Soluble Oil as a Lubricant and to retartd rust on the ferrous metal parts.

If you break down the word HYDRAaulics you will realize the original systems used WATER as the energy transfer medium. I called on one company in my area that was using City Water Pressure to power an 8" cylinder to compress some material for packaging. The water pressure was about 35 PSI so he was getting about 1,750# of thrust from the circuit.

Many aluminum companies use High Water Content Fluid (HWCF) in areas where they need hydraulic systems but are handling metal at 1,200 Deg.F. to avoid a catastrophic Fire Hazard in case of a blown hose or other fluid leaks. I'm sure the Steel producing facilities are also but I have only dealt with Aluminum.

The latest Fire Resistant fluid is Ethylene Glycol and Water at a 50-50 mix. This gives fire retardant Water plus a higher viscosity fluid that works similar to Oil in systems and can use components designed for Oil succesfully. When I say Latest that is not in years just the most recent. Been around for all my 50 years in Fluid Power.

The latest Fire Resistant fluid is Ethylene Glycol and Water at a 50-50 mix. This gives fire retardant Water plus a higher viscosity fluid that works similar to Oil in systems and can use components designed for Oil succesfully.

This sounds exactly like the coolant I use in my vehicles!! Am I correct??

Bill

Hi Sciesis2,

The first hydraulic systems worked with water as the fluid medium, hence the word "Hydraulic", But adding water to oil in hydraulic systems can wreck havoc.

First the water heats up and produces steam due to the pressues in the system during the working phase and this produces a spongyness, this is one of the worst things that can happen in hydraulic braking systems ie. on a road vehicle, you lose the braking power!!!!

Spencer.

Water and Glycerine, Glycerin or Glycerol (same product, words can be interchanged to represent the product). I have used it in large volume hydraulic systems, both low and medium pressure systems, in a 50/50 ratio.

Glycerin possesses a unique combination of chemical and physical properties and can be utilised in over 1 500 applications, in many industries. It is derived from either natural (animal fats, vegetable oils) or petrochemical feedstocks and I stand corrected, but I think that I read somewhere recently, synthetically.

Glycerin is a colourless, odourless, non-toxic, non-allergenic and an environmentally friendly, sweet liquid. It is actually better for you than sugur and it does not cause tooth decay............just a bit of trivia..............and.........MOST IMPORTANTLY it protects your hydraulic system from corrosion............don't have to worry about water contamination either. It was also very cheap.

One OH&s problem is that surfaces become very slippery if it is spilt or leaks onto a floor.

there are a couple of more imediat problems with mixxing water and hyd.oil. Hyd.oil is designed to absorbe a small amount of water to keep corosion under control add more water and it begins to become milky and starts to loose its lobricity. Add more yet it starts to sludge pluging filters and causing cavitation ,destroying pumps

There are only a few high pressure circut pumps designed for water but if you feel creative, a pressure washer pump could be swapped in and the valving changed to stainless steal ect.

I was also wundering if this was for cost or enviromental reasons if its enviromental there are verry good vegy based bio oils most of the mager oil companies have them

In a hydraulic press water works fine although usually mixed with some oil, given the restrictions and comments made by others about corrosion and such.

The one that usually only the experts get experience with is when someone is using a hydraulic motor as a hydraulic brake as well. Under these conditions if there is water in the system, the water boils and the brake fails.

Someone somewhere made a whoops of this sort and a multi-million ?billion? dollar submersible research vessel went to the bottom of the ocean as a result.... whoops....

Mr. Gee

can we use it in servo valve in steel plant we are using hlp 68

Hi...it is theoritically possibly to use water. Water has certain advantages viz indefinate flash point, low cost, enviorment friendly etc. But, the disadvantages outweigh the advantages mainly corrossion and being prone to organic decay (when kept stagnent).

But, there are firms who have developed technology to use water as a lubricating medium. You will find it in a modern hydro power station. Here the water is subjected to extreme certrifuge action inorder to remove all impurities. The water is always in circulation and does not deteriorate. Dissolved oxygen is removed. It's a good way.

AKT