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PD20X-X
GENERAL DESCRIPTION
The ARO diaphragm pump offers high volume delivery even at low air
pressure and a broad range of material compatibility options 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 differential in
the air chambers to alternately create suction and 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 it will continue to
pump and keep up with the demand. It will build and maintain line pres-
sure and will stop cycling once maximum line pressure is reached (dis-
pensing device closed) and will resume pumping as needed.
AIR AND LUBE REQUIREMENTS
WARNING
EXCESSIVE AIR PRESSURE. Can cause pump
damage, 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 required 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
Nitrile “O” rings in the air motor section of the pump.
OPERATING INSTRUCTIONS
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Always flush the pump with a solvent compatible with the material
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.
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The outlet material volume is governed not only by the air supply but
also by the material supply available at the inlet. The material supply
tubing should not be too small or restrictive. Be sure not to use hose
which might collapse.
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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 installed at the
air inlet.
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Secure the diaphragm pump legs to a suitable surface to ensure
against damage by vibration.
PARTS AND SERVICE KITS
Refer to the part views and descriptions as provided on page 4 through 7
for parts identification and Service Kit information.
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Certain ARO “Smart Parts” are indicated which should be available
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 SEC-
TION is divided further to match typical part MATERIAL OPTIONS.
MAINTENANCE
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Provide a clean work surface to protect sensitive internal moving
parts from contamination from dirt and foreign matter during service
disassembly and reassembly.
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Keep good records of service activity and include pump in preven-
tive maintenance program.
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Before disassembling, empty captured material in the outlet man-
ifold by turning the pump upside down to drain material from the
pump.
FLUID SECTION DISASSEMBLY
1. Remove (61) outlet manifold, (60) inlet manifold.
2. Remove (22) balls, (19) “O” rings (if applicable) and (21) seats.
3. Remove (15) fluid caps.
NOTE: Only PTFE diaphragm models use a primary diaphragm (7) and
a backup diaphragm (8). Refer to the auxiliary view in the Fluid Section
illustration.
4. Remove the (6) diaphragm washer, (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” cup with Lubriplate
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FML-2 grease (94276 grease packet is included in service kit).
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For models with PTFE diaphragms: Item (8) Santoprene diaphragm
is installed with the side marked “AIR SIDE” towards the pump cen-
ter body. Install the PTFE diaphragm (7) with the side marked
“FLUID SIDE” towards the (15) fluid cap.
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Re-check torque settings after pump has been re-started and run a
while.
Viton
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and Hytrel
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are trademarks of the DuPont Company,
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Kynar
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is a registered trademark of Penwalt Corp.
Santoprene
R
is a registered trademark of Monsanto Company, licensed to Advanced Elastomer Systems, L.P.,
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Lubriplate
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is a registered trademark of Lubriplate Division (Fiske Brothers)
