water cyliders 5

[Javier72]

I'm searching hydraulic cylinders to work with water. This last point is the most important one for my customer. They are going to work only in traction movement, and the force is low because they are going to be used to lift a weight of 300 kg. The total movement lenght is 1500mm. Does anyone know who could manufacture this kind of cylinders?

 

[prohammy]

Take a look at the following sites....they might help

http://www.purdue.edu/UNS/html4ever/010919.Krutz.mower.html

http://nessie.danfoss.com/Technology/Challenges.asp

The Danfoss one might help you....talk to their reps and see what they think

Kevin Hammond

Mechanical Design Engineer
Derbyshire, UK

 

[Javier72]

Thank you very much Kevin.

The principal problem is that the use of water is required by my costumer, I know the dificulties but the system is going to work very slow and the pressure is going to be lower while moving so I'm principallly worried because of corrosion and lubrication. Perhaps it could be possible to have treated water because I'm going to have a closed system.

Javier Castillo
Industrial Engineer

 

[prohammy]

Not too sure about treated water, I think that anything you treat the water with will probably cause you more headaches than it is worth (any number of environmental/legal issues) to provide corrosion resistance. It may however be possible to provide lubrication in this manner. Remember that they’re all going to be all sorts of possibility for leakage in your closed loop system.

I would think that with the correct material choice (if pressures and loads are low enough then maybe some sort of polymer may be a possibility) would be your best solution for the issue of corrosion. As I said earlier find a rep that is interested and see what you can get them to do for you.

I think it would be well worth posting this one on the Fluid Power Professionals forum as well, see if any of them have something to add.

Best of luck with the project


Kevin Hammond

Mechanical Design Engineer
Derbyshire, UK

 

[gerhardl]

Having experince in supplying for the Scandinavian market water driven double acting actuators, supplied from freshwater mains, actuators both linear and for 90 degrees - for valves: this is possibel and relatively trouble free, but depending on water quality.

Following points:

Water to be normal drinking/freshwater having passed a normal drinking water treatment plant.

Water must in addition be supplied over a fine (household) water filter (microsize), selfcleaning - handoperated or automated, directly in front or nearest possibel the cylinder.

Cylinder must be operated regularily to change the water. Cooler climate and water at least once a month, for warmer perhaps at least once a week or once each 48 hours?

Cylinder ought perhaps to be inspected after a trial periode to check for chalk or mineral deposits. (You actually will not know possibly negative chemical raections before you actually try, this could occur in some few cases, one per cent or less ?)

The customer must accept a possibel shortened lifetime.

We have had cylinders working trouble free for many years running, a few others from certain areas/locations that unexplained gives trouble -(could be false operating, poor filtering).

Soft sealings for cylinder to be supplied with cylinder, extra cylinder complete if critical.

Cylinder shaft to be equipped with scraper/sealing if available.

Hand operated or special solenoid valve for water to operate the cylinder (special types suitable)

Water is a non-compressibel medium and at low/normal pressure will need time to fill a cylinder through relatively small borings. Beware of necessary operating time! (Can be rougly calculated giving boring size and guessing at a sensible water speed)

Allow cylinder area to compensate for possibly lower water pressure than stated.

Cylinder material: quality grade aluminium could be used, but stainless steel recomended.

And last: why water operation to complicate things, air or electrical would be better?! What's wrong about a standard lifting table electrohydraulic or electric from floor up, or electric hoisting device from ceiling down. Even a oil-hydraulic cylinder with a smaller separate aggregate would probably have lower lifetime cost!

Main use in my area : To operate gate valves, mainly DN300 up to DN500 where water pipes are present, and electric not present, too complicated or costly. Cylinder material: aluminium, allowed for water by the cylinder fabricator.

 

[prohammy]

Good post Gerhardl, loads of good info for the OP

Cheers


Kevin Hammond

Mechanical Design Engineer
Derbyshire, UK

 

[btrueblood]

Prohammy,

I've tried sourcing stainless hydraulic cylinders here in the US, there are a number of manufacturers. Most of the devices I found were over-built for the pressures we intended to run (below 150 psi). In the end, we found it to be cheaper to manufacture our own cylinders, using drawn stainless tubing, epdm seals, and custom-made end caps. An "easy" end cap is to simply punch holes thru the thin-wall shell tube, drive a socket-head screw thru the wall into the end cap, and let the head of the socket-head screw protrude and retain the cap. We had good luck in hydrotests of prototypes using this method.

Then, we ended up going to a diaphragm cylinder, also a custom-made solution, for leakage reasons that have little to do with a typical hydraulic application.

 

[Javier72]

Thanks a lot Gerhardl. As you say, it could be much easier to do it by another way. In fact, my normal job is to design gearboxes. Why don't use them?. It is because that the water use is the principal customer specification. His project idea is to use water to move things. In the case I am working in, it is necesary to use cylinders. In other cases, other systems to be moved by water will be needed.

Thanks all for your opinions and indications. I have found, as recommended by btrueblood, who could manufacture my own cylinders with the indications given by all of you.

 

[EdDanzer]

Some air cylinders are constructed with stainless parts and will work with water.