User Manual

DF
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34
AIR COOLED DF
Performance Curves
Selection Procedure
Performance Curves are based on 50 SSU oil entering the cooler 50°F higher
than the ambient air temperature used for cooling. This is referred to as a
50°F E.T.D.
Step 1 Determine the Heat Load. Heat load may be expressed as either
horsepower or BTU/Hr. To convert horsepower to BTU/Hr.:
BTU/HR = Horsepower x 2545
Step 2 Determine Entering Temperature Difference. The entering oil
temperature is generally the maximum desired oil temperature.
Entering oil temperature – Ambient air temperature = E.T.D.
Step 3 Determine the Corrected Heat Dissipation to use the curves.
Corrected Heat Dissipation = BTU/HR heat load x
50°F x Cv
E.T.D.
50 60 70
80 90 100 200 400
300 500150
OIL VISCOSITY - SSU
OIL P MULTIPLIER
OIL P CORRECTION CURVE
5
4
3
2
1
OIL PRESSURE
DROP
= 5 PSI
= 10 PSI
OIL FLOW - GPM
HEAT DISSIPATION BTU/HR. AT 50˚F E.T.D.
3 4 5 6 7 8 9 10 15 20 25 30 40 50 60 70 80 90 100 150
50,000
40,000
30,000
25,000
20,000
15,000
10,000
9,000
8,000
7,000
6,000
5,000
DF - 11
DF - 12
DF - 22
Step 4 Enter curves at oil flow through cooler and curve heat dissipation.
Any curve above the intersecting point will work.
Step 5 Determine Oil Pressure Drop from Curves:
l = 5 PSI; n = 10 PSI; Multiply pressure drop from curve by
correction factor found in oil
s P correction curve.
Oil Temperature
Typical operating temperature ranges are:
Hydraulic Motor Oil 120°F - 180°F
Hydrostatic Drive Oil 160°F - 180°F
Engine Lube Oil 180°F - 200°F
Automatic Transmission Fluid 200°F - 300°F
C
V
Viscosity Correction
OIL
SAE 5 SAE 10 SAE 20 SAE 30 SAE 40
Average 110 SSU at 100°F 150 SSU at 100°F 275 SSU at 100°F 500 SSU at 100°F 750 SSU at 100°F
Oil Temp °F 40 SSU at 210°F 43 SSU at 210°F 50 SSU at 210°F 65 SSU at 210°F 75 SSU at 210°F
100 1.14 1.22 1.35 1.58 1.77
150 1.01 1.05 1.11 1.21 1.31
200 .99 1.00 1.01 1.08 1.10
250 .95 .98 .99 1.00 1.00
5
4
3
2
1
50 500400300200100
Oil P Correction Curve
Oil P Multiplier
Oil Viscosity SSU