Page 4 of 20
SD20X-XXX-XXX-BXXX (en)
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Loctite® is a registered trademark of Henkel Loctite Corporation
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Santoprene® is a registered trademark of Monsanto Company, licensed to Advanced Elastomer Systems, L.P.
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ARO® is a registered trademark of Ingersoll Rand Company
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Lubriplate® is a registered trademark of Lubriplate Division (Fiske Brothers Refining Company)
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262™, 271™ and 572™ are trademarks of Henkel Loctite Corporation
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GENERAL DESCRIPTION
The ARO diaphragm pump offers high volume delivery even at low
air pressure and a broad range of material compatibility options are
available. Refer to the model and option chart. ARO pumps feature
stall resistant design, modular air motor / fluid sections.
Air operated double diaphragm pumps utilize a pressure differen-
tial in the air chambers to alternately create suction and a positive
fluid pressure in the fluid chambers, valve checks ensure a positive
flow of fluid.
Pump cycling will begin as air pressure is applied and will continue
to pump and keep up with the demand. It will build and maintain
line pressure and will stop cycling once maximum line pressure is
reached (dispensing device closed) and will resume pumping as
needed.
AIR AND LUBE REQUIREMENTS
WARNING
EXCESSIVE AIR PRESSURE. Can cause pump dam-
age, personal injury or property damage.
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A filter capable of filtering out particles larger than 50 microns
should be used on the air supply. There is no lubrication re-
quired other than the “O” ring lubricant which is applied during
assembly or repair.
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If lubricated air is present, make sure that it is compatible with
the “O” rings and seals in the air motor section of the pump.
INSTALLATION
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Verify correct model / configuration prior to installation.
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Re-torque all external fasteners per specifications prior to start
up.
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Pumps are tested in water at assembly. Flush pump with com-
patible fluid prior to installation.
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When the diaphragm pump is used in a forced-feed (flooded
inlet) situation, it is recommended that a “Check Valve” be in-
stalled at the air inlet.
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Material supply tubing should be at least the same diameter as
the pump inlet manifold connection.
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Material supply hose must be reinforced, non-collapsible type
compatible with the material being pumped.
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Piping must be adequately supported. Do not use the pump to
support the piping.
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Use flexible connections (such as hose) at the suction and dis-
charge. These connections should not be rigid piped and must
be compatible with the material being pumped.
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Secure the diaphragm pump legs to a suitable surface (level
and flat) to ensure against damage by vibration.
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Pumps that need to be submersed must have both wet and
non-wet components compatible with the material being
pumped.
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Submersed pumps must have exhaust pipe above liquid level.
Exhaust hose must be conductive and grounded.
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Flooded suction inlet pressure must not exceed 10 psig (0.69
bar).
OPERATING INSTRUCTIONS
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Always flush the pump with a solvent compatible with the ma-
terial being pumped if the material being pumped is subject to
“setting up” when not in use for a period of time.
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Disconnect the air supply from the pump if it is to be inactive
for a few hours.
PARTS AND SERVICE KITS
Refer to the part views and descriptions as provided on pages 5
through 10 for parts identification and service kit information.
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Certain ARO “Smart Parts” are indicated which should be avail-
able for fast repair and reduction of down time.
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Service kits are divided to service two separate diaphragm
pump functions: 1. AIR SECTION, 2. FLUID SECTION. The Fluid
Section is divided further to match typical part MATERIAL OP-
TIONS.
MAINTENANCE
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Provide a clean work surface to protect sensitive internal mov-
ing parts from contamination from dirt and foreign matter dur-
ing service disassembly and reassembly.
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Keep good records of service activity and include the pump in
preventive maintenance program.
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Before disassembling, empty captured material in the outlet
manifold by turning the pump upside down to drain material
from the pump.
FLUID SECTION DISASSEMBLY
1. Remove (61) outlet manifold and (60) inlet manifold.
2. Remove (22) balls, (19 and 33) “O” rings (if applicable) and (21)
seats.
3. Remove (15) fluid caps.
NOTE:
Only PTFE diaphragm models use a primary (7) diaphragm
and a backup (8) diaphragm.
NOTE:
Do not stretch or bend the clamp during disassembly. Loos-
en the fastener to free the clamp and move the clamp to the air
cap side of the pump to remove the fluid cap.
4. Remove the (14) screw and (6) diaphragm washer (if applicable)
(7) or (7 / 8) diaphragms, and (5) backup washer.
NOTE:
Do not scratch or mar the surface of (1) diaphragm rod.
FLUID SECTION REASSEMBLY
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Reassemble in reverse order. Refer to the torque requirements
on page 5.
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Clean and inspect all parts. Replace worn or damaged parts
with new parts as required.
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Lubricate (1) diaphragm rod and (144) “U” cups with Lubriplate®
FML-2 grease (94276 grease packet is included in service kit).
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For models with PTFE diaphragms: Item (8) Santoprene dia-
phragm is installed with the side marked “AIR SIDE” towards the
pump center body. Install the (7) PTFE diaphragm with the side
marked “FLUID SIDE” towards the (15) fluid cap.
NOTE:
For PTFE one-piece composite diaphragm SPECIAL IN-
STRUCTIONS. Refer page 15-20 for more detailed INSTALLA-
TION SEQUENCES: Apply 5-8 psig of air pressure to ensure the
first air connecting side of the air cap. Tighten PTFE one-piece
composite diaphragm on connecting rod, ensuring back side
of diaphragm is flush with backup washer and connecting rod,
then insert rod into pump center body. Push diaphragm to first
side then clamp on fluid cap. Install and tighten diaphragm on
other side, in similar fashion to other side. Apply 5-8 psig of air
pressure to slowly draw diaphragm down, taking care not to ac-
tivate trip pin (and thus shifting the diaphragm). Install second
fluid cap.
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Examine torque settings after the pump has been re-started
and run a while.
