Inches of mercury conversion to suction of oil

[PutnamVictor]

ISO 32 hydro works in most tractors in most weather. 15w-40 works fine in my T5C when it's too cold to dig, warms up just fine as expected.

View attachment 682967

Neighbor is a supervisor for GDL, says they use ISO ("light hydraulic") in all their garbage trucks. They don't get many days off for cold weather.

The conversion table is very helpful, thanks.

 

[SPYDERLK]

I'm looking at a Hydro-Gear pump that states a continuous inlet vacuum of 4 inches of mercury. That converts to 54 inches of water. So since oil is lighter than water, can I place the pump 54" above the tank?

My uncertainty is that I'm not taking into account the viscosity difference, the diameter of the suction line, or even something else?

Isnt that 4"Hg figure an absolute pressure number? ... That would mean the vacuum the pump will draw is actually 30 - 4 = ~26" Hg (~ 26' H2O) at sea level.

:confused3:​

 

[RalphVa]

I'd be worried about sucking that heavy oil up that far in other than a huge suction pipe. Otherwise, the friction loss would be very large.

That ISO 32 stuff would be much more acceptable.

Ralph

 

[RalphVa]

If you used the much lighter ISO 32 stuff and raised the pump up and put in a check footer valve and primed it first, you should be able to get it pumping. If you had no way of priming it, it might take forever to get liquid suction.

Ralph

 

[RalphVa]

Might be a tad lighter than xxw60, more like xxw40 based on the chart PutnamVistor posted, e.g. 14 cSt @ 212 F and 135 cSt @ 104 F. Still plenty heavy.

I'd find some of that ISO 32 stuff.

Ralph

 

[the old grind]

The meaningful suction lift is the difference between the level of hydro in the tank and the height of the pump above or below it.

Fluids seek their own level. 'Cold' oil that flows at temp will do just that. Nobody runs for long with the oil still 'cold' so I don't get how hydro is much different than motor oils during warm-up..

btw, many of our grinding shop machines used oil to move the tables under the wheels. (ISO 32) We run them empty (table back & forth) to warm the oil in the system prior to setting up a job. When I'm warming up to move snow I cycle the FEL & bucket as part of the routine. (40w oil at temp runs about as 'thick' as whole milk.) Multi-weight oils just thin less as they come up to temp. 40w, 10w-40, 15w-40 would have the sane viscosity at 180 deg F. The 'x'w part is their viscosity at STP.