HYDRAULICS INC.

Division of OLAER Ind.

OAD
Air Oil Cooler

Mobile hydraulic systems

High performance
Compact size
Rugged construction
 HYDRAULICS INC.

Balanced oil temperatures - the key to efficiency in hydraulics

Maintaining the correct system temperature is important to
ensure optimum performance in a hydraulic system.
140
In many hydraulic systems, up to 50% of the available
horsepower can be lost due to inefficiencies in the system.
These inefficiencies include friction, pressure drops and 130 150
changes/interruption of flow. The end result of these losses is
the production of heat.

When the heat generated is greater than the amount that can be 120 o
F 160
naturally dissipated by the system, the fluid temperature will
rise until the rate of heat production is equal to the amount of
heat dissipated. Unfortunately, in many systems, this point of We recommend that the working temperature is held between 1300 F and
equilibrium is at a temperature that can damage both the fluid 1500 F. (for mobile hydraulic systems). A correctly calculated cooler ensures
and hydraulic components. optimum efficiency.

Harmful side effects of excessive temperature include OAD and OAH cooler specially
reduction in fluid lubricity, destruction of helpful fluid
additives, oxidation of the fluid and “varnishing” of system designed for mobile hydraulic
components. These effects in turn lead to greater energy applications
losses and more heat generation, forming a destructive cycle.
The OilAir OAD cooler (DC-motor driven fan) and OAH
cooler (Hydraulic motor driven fan) are designed primarily for
The cooler provides reliable mobile applications. Typical applications include:
temperature control
The oil cooler dissipates heat from the system providing • Cooling of mobile hydraulics such as cranes, logging
equipment and mining equipment.
reliable temperature control of hydraulic fluids. The correct
size of cooler and type of fluid ensure a properly operating • Re-cooling of compressors on the air side as well as on the
oil side.
system. Inherent advantages include:
• Cooling of Diesel-engine oils.

• Hydraulic system life extended by 3-5 times. • Cooling of mobile hydraulics on drill rigs.

• Long lasting oil durability. • Additional cooling of engine oils and mobile hydraulics
under extreme conditions (such as tropical environments).
• Reduced internal potential for leaks.
• Cooling of engine oils on mobile and stationary generating
• Prolonged lubricating qualities. units.
• Improved hydraulic efficiency.

OilAir offers the best cooler to A typical field application for the OAD
is cooling of mobile cranes. Minimized
meet every requirement. operating costs and fast loading are
two very important benefits with a
At OilAir we specialize in solving complicated overheating correct hydraulic system temperature.
problems in all types of hydraulic systems. Our wide range of Compact size and lightweight
permit easy installation in all
cooler sizes and types enables us to offer the cooler that best kinds of mobile applications.
meet your needs. Our other wide range of standard air oil
coolers are grouped in four main series:

OAI AC motor driven air oil cooler designed for

industrial and stationary equipment.
OAO AC motor driven offline air oil cooler with an
integrated circulation pump.
OAH Hydraulic motor driven air oil cooler designed for
mobile equipment.
OAD DC motor driven air oil cooler designed for mobile
equipment.

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 OAD
Cooling Capacities
2000
See example for obtaining the total
1800 cooling capacity from the graph.
33

1600

1400
23

1200
Btu/hr/ F
0

1000

16
800

11
600

07
400
04
200

0
0 10 20 30 40 50 60 70 80 90
Flow Rate (gpm)

Oil pressure drop curves with correction factors for other viscosities Model BPO
60
Pressure Drop at 150 SSU (psi)

Correction Factor

50 2

1
33
23
0
50 150 250 350 450
40 SSU
1
,1

30 04
07

20

10

0
0 20 40 60 80

Oil Flow Rate (gpm)

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 HYDRAULICS INC.

Typical characteristics that make the OilAir Technical Specifications for the
OAD type of air oil cooler ideal for mobile Cooler core
applications.
• Dynamic working pressure: 200 psi.
• Maximum static pressure: 300 psi
• Compact size and lightweight.
• Maximum oil inlet temperature in 2500F. Oil temperature
• High physical strength and durability. above this will reduce maximum working pressure rating.
• Extremely quiet compared to conventional air oil coolers.
• Easy to retrofit on all types of machines.
• Unlimited utilization of all accessory units
Fluid compatible with OAD
• Ease of maintenance (held together by 8 bolts only)
aluminum cooler core
OAD Material
• Mineral oils
• Core: Aluminum • Oil/water emulsion
• Fan Blades: Fiber glass reinforced polypropylene • Water glycol
• Fan Housing: Steel • Phosphate ester
• Fan Guard: Steel

Surface treatment Factors affecting heat dissipation

• All steel components are electrostatic blast coated with • Limits of heat dissipation in graph +/- 6%
epoxy plastic powder. • Viscosity’s above 450 SSU (70 cSt) will cause reduction in
heat dissipation. Consult our factory.
• The cooler core has a layer of protective diffused zinc to
withstand corrosion before receiving a final coat of • For aggressive environments ambient air may contain dust
electrostatic epoxy plastic powder. particles that will increase air fin clogging coefficient.
• Consult OilAir Hydraulics Inc. for use in aggressive or • Operating coolers at altitudes above 1300 feet will reduce
corrosive environments. heat dissipation. Consult factory.

Technical Specifications for

OAD-04 OAD-07,11, 16
23** & 33**
Electrical Motors
Weight 4.6 Lbs 5.39 Lbs • Long lasting, high quality motors available
RPM 3350 rpm 3060 rpm in 12V and 24V DC.
Noise Level 70 dB(A) 70 dB(A) • Enclosed for protection

Protection Standard IP 64 IP 64
• Please refer table on page 5 for power consumption

Insulation Class H H
Ambient Temp. -22 F to +176°F -220F to + 1760F
0

Life Expectancy 5,000 Hrs. 8,000 - 10,000 Hrs.

** OAD 23 & 33 is twin-fan motor

Dimensions in Inches

Type A B C D E F G H I

OAD 04 9.84 8.66 - 2.91 10 0.15 8.58 3 0.55

OAD 07 13.38 11.81 - 3.54 13.54 0.15 8.18 3.54 0.98
OAD 11 15.74 14.17 8.93 3.22 15.6 0.15 8.97 3.97 0.8
OAD 16 17.95 16.37 9 3.14 18.14 0.15 8.97 3.97 1.08
OAD 23* 24.2 14 12 4.68 25 0.78 8.97 11.41 5.11
OAD 33* 24.8 14.6 15.98 3.38 26.7 0.78 10.2 11.41 5.11
** OATBD 23 is dual fan

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 OAD
G

OAD 04 J
2.56

D
AIR

E
B

F
I
A Slot o .433x.67 (4x)
.39 H .39

OAD 7, 11&16
External Bypass Option G
J 2.56

D
AIR

C
E
F
B I
A Slot o .35x1.14 (4x) .39 H .39

OAD 23 & 33
G

External Bypass Option J 2.56

K
D
C

AIR
E
F

B o.5(4x) I 1.61
A .59 H .59

Type J K Air Flow Max. cons.of current Fuse Weight Lbs

CFM OAD 24V 12V OAD 24V 12V (Approx)

OAD 04 1.96 1-5/16”-12UN 509 6A 10A 10A 15A 10

OAD 07 1.57 1-5/16”-12UN 806 11A 20A 15A 25A 22
OAD 11 2.36 1-5/16”-12UN 1082 11A 20A 15A 25A 27
OAD 16 2.36 1-5/16”-12UN 1315 11A 20A 15A 25A 33
OAD 23* 2.36 1-5/16”-12UN 2015 2x11A 2x20A 2x15A 2x25A 55
OAD 33* 3.93 1-5/8”-12UN 2892 2x11A 2x20A 2x15A 2x25A 66

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 HYDRAULICS INC.

Piping diagram for the OAD air oil cooler

No Bypass No Bypass With Bypass

M M M

Type OAD 04 Type OAD 07 - OAD 33 Type OAD 07 - OAD 33

Oil inlet connection may be Oil inlet connection may be Oil inlet connection is located on
located either on the right or on the located either on the right or on the the left side of the matrix (on the
left side of the matrix. The oil left side of the matrix. The oil by-pass valve side). The oil outlet
outlet connection is always located outlet connection is always located connection is always located on
on the opposite side of the matrix. on the opposite side. There are two the opposite side. There are two
connections on the left side, one connections on the left side, one
of these has be plugged. of these has to be plugged.

With Thermo Switch Model C & CB

Model Code
OAD 11 - x - x - x
M
Thermo-contacts available:
Temp TV 100/120/160/175 °F
Cooler
Size
C100 = With thermo-contact set at 100°F
CB120 = With relay, fuse, switch box,
thermo-contact TV 120°F

Built in External By-Pass Valve

Model BP1
DC-motor Type of by-pass valve
Voltage 12V or 24V BP1.2 = With built-in-by-pass valve 20 psi
M BP1.5 = With built-in by-pass valve 65 psi

Ordering Example: OAD 11 - 12V - BP1.2 - CB120

6
 OAD

Service instructions
Location
Noise level
Place the cooler so that
there is an unrestricted The noise level of the oil cooler may vary within +/-3 dB
air flow to and from the AIR (A) depending on reflections from surrounding objects,
cooler. The distance natural frequency and other interference sources etc.
from the nearest wall 1/2 core 1/2 core
should not be less than height height Suspension
half the height of the The very rigid cooler construction permits both vertical and
core. horizontal mounting. Mounting is facilitated by four
mounting holes in each support leg of the cooler. There is a
Cleaning of air fins mounting flange in the front of the air oil cooler for wall
The easiest way to clean the air fins is by using compressed mounting next to a ventilator shaft or similar structure.
air or rinsing with water. Fouling can be dealt with using a
degreasing agent and a high pressure washing system. Connection to the system
When using a high pressure washing system, point the jet The air oil cooler is intended to cool the system’s return oil.
carefully parallel to the air fins. Use hydraulic hoses both to and from the cooler. Avoid
hydraulic tubes, unless stress-free joints can be guaranteed.
Cleaning the inside of If there is a risk of pressure spikes or flow peaks the cooler
oil cooling tubes should be installed with a bypass valve. If the viscosity of
the oil is 450 ssu at cold start, use a full flow pressure or
Connect the cooler to a closed circuit and flush the inside
temperature bypass valve external to the cooler.
with perchlorethylene. After cleaning, the radiator should
be flushed with oil before reconnecting to the hydraulic
system.

Useful Technical Information Examples

Recommended Maximum Oil Temperature:
Industrial Hydraulic Systems: 110°F - 130°F Given: Fluid Type SAE 10
Mobile Hydraulic Systems: 130°F - 150°F Flow Rate 25 GPM
Mobile Hydrostatic Transmission: 160°F - 170°F Desired Oil Temperature 130°F
(Inlet to Cooler)
Formulas Ambient Air Temperature 80°F
1 HP = 746 Watts = 2545 Btu/hr Altitude <3,000 feet
1 kW = 1.34 HP = 3412 Btu/hr Heat Dissipation Required 30,000 Btu/hr
Temperature conversion °F = °C x 1.8 +32
Required: Type of air oil cooler
Heat Equivalent of Fluid Power
HP heat = (PSI x GPM)/1714 Temperature Difference (∆T)
BTU/hr heat generation = 1.5 x PSI x GPM (∆T) = 130°F - 80°F = 50°F
Heat dissipation per °F (P) = 30,000/50
Heat Radiation from Steel Reservoirs P = 600 Btu/hr/°F
HP Radiation = .001 x T.D. x A Refer to the cooler capacity chart.
Where A = Surface area in Sq. Ft. Plot the 600 Btu/hr/°F against the flow
TD = Temperature difference in °F
Between reservoir surface and of 25 GPM
surrounding air We recommend Cooler model #OAD 11

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 HYDRAULICS INC.

HYDRAULICS INC.

OILAIR HYDRAULICS, INC.

11505 West Little York
Houston, Texas 77041
Tel: (713) 937-8900
Fax: (713) 937-0438
www.fluidpower.com

A r o u n d Norway
Oiltech AS
t h e W o r l d Dynamitveien 23, PB 133
NO-1401 Ski
Tel: +47 64 87 42 65
Fax: +47 64 87 43 21
Germany
Olaer Industries GmbH Poland
Zum Gunterstal 4 Oiltech AB
DE-66440 Blieskastel UL. Pytlasinskiego 13A
Australia Tel: +49 6842 9204 0 PL-00777 WARSZAWA
Olaer Fawcett Christie Pty Ltd Fax: +49 6842 9204 15 Tel: +48 601 217440
1/13 Sydenham Rd., Brookvale Fax: +48 22417992
P. O. Box 57, Warringah Mall Holland
Sydney, NSW 2100 Olaer Nederland B. V. South Africa
Tel: +61 2 9938 4444 De Lind 10, Postbus 75 Fawcett Christie Hydraulics
Fax: +61 2 9938 6879 NL-4840 AB Prinsenbeek c/o Rolton Products CC
Tel: +31 76-5412453 P.O. Box 43244
Austria Fax: +31 76-5411502 ZA-Industria 2042
Olaer Speicher-Technik GmbH Tel: +27 11 474 3095
Haiderstrasse 38 Hong Kong Fax: +27 11 474 8384
AT-4052 Ansfelden Olaer Asia Pacific Ltd
Tel: +43 7229 80306 Unit 12, 12/F, Block B Spain
Fax: +43-7229 80306-21 Hoi Luen Ind. Building Olaer-Oiltech Iberica, S.A.
55 Hoi Yuen Rd, Kwun Tong Travesia Industrial, no 29
Belgium Kowloon ES-08907 L’Hospitalet de LI.
S.A. Olaer Benelux N.V. Tel: +852 23 31-27 80 (Barcelona)
Doornveld 4 Fax: +852 23 31-29 00 Tel: +34 3 336 14 12
BE-1731 Zellik Fax: +34 3 335 71 86
Tel: +32 2 466.15.15 India
Fax: +32 2 466.16.24 Narsipur Fawcett Christie Sweden
Hydraulics Oiltech AB
Denmark C 30 Shankara Park Forradsvagen 2
Oiltech AB Bangalore 560 004 SE-181 41 Lidingo
Mollebaekvej 14 Tel: +91 806 61 05 08 Tel: +46 8 765 16 00
DK-9632 MOLDRUP Fax: +91 806 61 17 16 Fax: +46 8 767 97 56
Tel: +45 86 69 20 38
Fax: +45 86 69 23 38 Italy Switzerland
Olaer Italiana S.pA. Olaer (Schweiz) AG
Finland Strada Fantasia 83 Bonnstrasse 3
Oiltech Hydraulics OY IT-10040Leini (TO) CH-3186 Dudingen
Vattuniemenkatu 8, Pl 190 Tel: +39 11 998.02.22 Tel: +41 26 492 70 00
FI-00210 Helsinki Fax: +39 11 998.02.02 Fax: +41 26 492 70 70
Tel: +358 9 682 0422
Fax: +358 9 682 2376 Korea United Kingdom
Fawcett Christie Korea Ltd. Fawcett Christie Hydraulics Ltd.
France 2NA-702, 1259-1 Shi-Wha Sandycroft Industrial Estate
Olaer Industries S.A. Industrial Complex Chester Rd, Sandycroft
16, rue de Seine, B.P. 7 Joung Wang-dong Deeside, Flintshire CH5 2QP
FR-92704 Colombes Cedex Shi Hung-Shi, Kyunggi-Do Noth Wales
Tel: +33 1 41 19 17 00 Tel: +82 345 499 07 97 Tel: +44 1244 535515
Fax: +33 1 41 19 17 20 Fax: +82 345 499 22 49 Fax: +44 1244 533002

© copyright 2002 OilAir Hydraulics, Inc. Printed in the USA Bulletin OAD