Originally Posted By: zeng
Yes, the temperatures were in relation to a baseline of minimum 10 cSt as recommended by some Asian gear pumps , not sure if Rexroth is inclusive.
Optimum viscosity would be in the range of 13-26 or thereabouts.
One of the big boys in the US is the ex Haldex-Barnes, now Concentric; they give 10 cSt as their minimum. Rexroth concurs. If it were my equipment, I'd recommend 16-32 as the "optimum" range, AT OPERATING TEMPERATURE. Eaton says 6 minimum, 10-43 optimum, so there is a big player allowing it thinner than I like. Parker recommends 16-200 ...
Volumetric efficiency is lower with thinner fluids. Friction is higher with heavier fluids. I'd expect greater wear with thinner fluids, but cannot support that with references.
One application with which I have too much experience operates ATF at about 300F with vane pumps at pressures around 1500 psi. Pump life is miserable, but that's the penalty paid to do what is required.
There is no free lunch.
Yes, the temperatures were in relation to a baseline of minimum 10 cSt as recommended by some Asian gear pumps , not sure if Rexroth is inclusive.
Optimum viscosity would be in the range of 13-26 or thereabouts.
One of the big boys in the US is the ex Haldex-Barnes, now Concentric; they give 10 cSt as their minimum. Rexroth concurs. If it were my equipment, I'd recommend 16-32 as the "optimum" range, AT OPERATING TEMPERATURE. Eaton says 6 minimum, 10-43 optimum, so there is a big player allowing it thinner than I like. Parker recommends 16-200 ...
Volumetric efficiency is lower with thinner fluids. Friction is higher with heavier fluids. I'd expect greater wear with thinner fluids, but cannot support that with references.
One application with which I have too much experience operates ATF at about 300F with vane pumps at pressures around 1500 psi. Pump life is miserable, but that's the penalty paid to do what is required.
There is no free lunch.