Propylene Glycol hydraulic fluids

[George Bynum]

I'm doing in-house qualification testing on a system for which my customer will be using a propylene glycol fluid. He has a corporate mandate for the fluid, but no brands or products are mentioned. He has required us to use a propylene glycol fluid at a 40% concentration.

On the web, I find that Dow has UCON and LubeCorp has Lubritherm All-Temp. Neither are stocked locally (upstate SC). While this is a positive displacement hydraulic system, the pressure is low (under 250 psi for sure) and I'd consider Prestone LowTox or Peak Sierra; I suspect there to be sufficient lubricity for our tests. The RV products have no lubricity additives at all from what I have been told, and won't work with a positive displacement pump.

Do any of you have other products you would recommend? The test setup won't need but about 10 gallons of 100% fluid.

Thanks!

 

[Ken42]

I would ask Tom in NJ

 

[Steve S]

What is the hydraulic system on?

 

[MolaKule]

Yes, what type of system?

Quote:
I'm doing in-house qualification testing on a system for which my customer will be using a propylene glycol fluid. He has a corporate mandate for the fluid, but no brands or products are mentioned. He has required us to use a propylene glycol fluid at a 40% concentration.



40% PG, or PEG or 40% PAG and 60% water?

Is this for a Food Grade lubrication application?

Dow has a whole bunch of glycols; I would call Dow and ask for an application engineer/chemist.

 

[George Bynum]

For Steve and Mola ...

What type of system and what the system is on really doesn't apply to the question ... we were mandated by our customer to use a propylene glycol fluid at 40% concentration. I see 2 "home type" antifreeze solutions, Prestone LowTox and Peak Sierra which should do at these pressures. As these have little in the lubricity and antiwear additives, I would RATHER use a PG based hydraulic fluid. I found 2 in a web search, Dow UCON and LubeCorp Lubritherm AllTemp. I turned that information over to purchasing.

My test only needs about 20 gallons of 40% solution, and they had some trouble finding the hydraulic fluids in small quantities anywhere, and at all locally. I posted here looking for other options from the experts.

This customer is protective of their intellectual property, even to us with company officer signed NDAs, but I can answer in the abstract.

We are evaluating flowmeters for use on a future system addition. The flowmeters monitor a process fluid which we were initially told was a water-glycol with 40% glycol. I regularly work with "less flammable fluids", the most common of which are ethylene glycol based, and for which we have numerous sources. Steel mills and die casting almost universally use water-(ethylene)glycol. Until the notice that PG was required vs EG, we were in good shape.

I'm using a positive displacement pump (gear type) with a VFD on an electric motor to cover the 2.2:1 flow range over which they want data collected. I've a fairly complete test procedure which will run for an estimated (by me) 25 to 50 hours. I predict my maximum pressure will be under 100 psi. The components, conductors, and meters used are all rated at least 1450 psi (100 bar). The meters are more sophisticated than what I would normally use in industrial hydraulics, Coriolis and vortex shedding styles.

Our test is certainly not a food grade situation. I'd rather not answer specifically, but will quote them ... "disposal is less of an issue".

As for "Dow has a whole bunch...", purchasing asked us for help after talking to Dow ... whether price (our time is valuable too and they know that) or availability, I'm unsure, but feel it is availability.

Asking Dow for non-Dow alternatives ... if you asked me for an alternative to what I represent, I'd suggest you find it yourself ... ... and have been given that answer by others.

 

[MolaKule]

Ok, it sounds as if for your test(s) the Prestone LowTox or Peak Sierra PG fluids should work as long as your viscosity requirements are for a 2.5 to say 3.5 cSt fluid.

I would have reservations about the wear on the gear pump.

I would take a sample of the PG mix before and after to see how much wear metals I am getting from the pump.

 

[George Bynum]

Originally Posted By: MolaKule
Ok, it sounds as if for your test(s) the Prestone LowTox or Peak Sierra PG fluids should work as long as your viscosity requirements are for a 2.5 to say 3.5 cSt fluid.
That's lower than I WANT, but with a total of less than 100 hours at 5% of the pump's rated pressure, I'm willing to take the volumetric efficiency loss.
Originally Posted By: MolaKule

I would have reservations about the wear on the gear pump.
I do to, but I suspect it will be inconsequential in the time involved. I've run these for thousands of hours at 1000 psi with less than 5% soluble oil in water ... which I predicted failure in minutes ... sometimes I'm glad to be wrong.
Originally Posted By: MolaKule
I would take a sample of the PG mix before and after to see how much wear metals I am getting from the pump.
We'll do a simple patch test. There's not even (GASP) a filter of any type in the system.

We'll hear the scream of galling if it occurs. The electric motor is only 1.5HP for 12 GPM, so we don't exactly have to worry about wringing a shaft at the torques we might see. .

Back to the original question ... beyond the PG antifreeze products, the UCON and the AllTemp hydraulic fluids, are you aware of other PG products? I'd REALLY like to get into a fluid with more "hydraulic type" viscosities ... ISO 15 at least, ISO 32 would be better. Shoot me a PM with an email address and I'll send you a company proprietary purged pdf of the circuit.

 

[ac_tc]

Both PG and EG´s are used in aircondition systems for buildings.
(brine) we buy em in 20 l cans up to 1m3 cans.
They differ from automotive af in that they have less corrision protection due to the fact that these systems arent a metalurgical nighmare like the average engine is.
These system are also quite big carrying 100éds of liters or more of af.
get em att your local hvac dealer.
But id suspect that the viscosity isnt different between brands
at all since we´re taliking the same molecule whatever...
The only option you have is the mixing factor.
danfoss have built waterbased hydraulics.