Piston Pump Basics

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Piston Pump Basics

• Piston Pumps
• Upsize!
• FRLs are the fries
• Piston Pumps are the burger

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Usage of Piston Pumps
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What is a Piston Pump

• A pump that uses a reciprocating piston to
  produce fluid flow
• Because they produce higher fluid pressures, they
  can pump higher viscosity fluids

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Terminology Viscosity

• Viscosity is resistance to flow
• Piston pumps are used with medium to high
  viscosity fluids
• Medium Viscosity fluids
• 50,000 to 100,000 cP
• High Viscosity fluids
• 100,000 cP

Viscosity of Common ProductsWater 1 Centipoise
(cP) Beer 3 cP SAE 30 Motor Oil 200 cP White
Glue 1000 cP Ketchup 50,000 cP Petroleum
Jelly 64,000 cP Tooth Paste 190,000 cP Peanut
Butter 250,000 cP
Low
Medium
High
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Terminology Ratio

• The difference in effective size between the Air
  Motor Piston and the Lower End Plunger Rod
• Higher ratio pumps produce higher fluid
  pressures

Comparison of relative Air Motor Piston and
Plunger Rod sizes
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Ratio / Pressure Calculation

• Use Pump Ratio and Air Inlet Pressure to
  determine fluid pressure Pump Ratiox Air
  Inlet PSI Fluid Outlet Pressure

Example Pump Ratio 41 Air Inlet
Pressure 100-psi
Calculation 41 Pump Ratio x 100-psi
Air Inlet Pressure 400 Fluid Outlet Pressure
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Pump Components

• The Air Motor creates the motion to drive the
  pumpNote NOT a vane motor
• The Lower End (pump) uses reciprocating motion
  from the motor to create fluid flow

Air Motor
Lower End
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Pump Design Inline Pumps

• Often used with lubricants like motor or cutting
  oils
• The Down Tube is coupled to the Air Motor Casting

Air Motor
Fluid Outlet
Lower End
Inline Pumps have a direct connection between the
Motor and Lower End
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Pump Design Divorced Design

• Motors and Lower Ends are separate from each
  other
• Tie Rods connect the Motor to the Lower End

Air Motor
Fluid Outlet
Lower End
Prevents contamination of Air Motor when Lower
needs repair
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Air Motor Components

• Valving
• Controls air distribution
• Piston
• Creates reciprocating motion
• Piston Rod
• Transfers motion to the Pump Lower End

Motor Valving Mechanism
Piston
Piston Rod
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Lower End (Pump) Components

• Plunger Rod
• Uses reciprocating motion to produce fluid flow
• Packings
• Used to seal fluid flow within pump
• Checks
• Control fluid flow within pump

Plunger Rod
Packing Assembly
Check Assembly
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Pump Types

• Basic Pumps
• Two-Ball Lower End Pumps
• Four-Ball Lower End Pumps
• Chop-Check Lower End Pumps

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Basic Pumps

• For low-volume delivery of light viscosity
  fluids(gt1,000 cP)
• Ratios range from 11 to 21

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Two-Ball Pumps

• Lower End contains two Ball Checks that control
  fluid flow
• Most common type of pump configuration
• Used with light to medium viscosity fluids
  (0-100,000 cP)

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Two-Ball Lower Operation

• Upstroke As the Piston rises, fluid is pulled
  into the pump. Fluid above the ball check is
  lifted out of pump.

Downstroke The lower ball seats to close off the
pump. Fluid is displaced by the plunger, passing
through the upper ball check, to the outlet.
Downstroke
Upstroke
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Four-Ball Pumps

• The Lower End contains four Ball Checks that
  control fluid flow
• Used with low viscosity fluids in high flow
  applications
• Most common application is recirculating paint

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Four-Ball Lower Operation
Upstroke Fluid passes the lower left ball check
into pump. Upper left check is seated. The upper
right check rises as fluid exits the pump. The
lower right check is forced onto its seat.
Downstroke The lower left ball is seated. The
upper left ball rises as fluid exits the pump.
The upper right check is seated, while fluid is
drawn into the pump past the lower right check.
Downstroke
Upstroke
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Chop-Check Pumps

• The checks literally chop, or cut the fluid
• Checks are mechanically pushed onto seats to
  control fluid flow
• Used in extrusion applications with heavy fluids,
  with medium to high viscosity
• An example is silicone

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Chop-Check Lower Operation
Upstroke The lower check rises and the primer
plate pulls fluid into the pump. Fluid exits the
pump when the upper check seats and rises with
the plunger.
Downstroke The lower check seats and the upper
check opens. Fluid exits the pump through the
upper check. Meanwhile, the primer plate extends
into the fluid. It will pull fluid into the pump
when the plunger rises.
Downstroke
Upstroke
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Pump Components

• Packing Assemblies
• Tube Plunger
• Springs
• Wet Cup

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Packing Assemblies

• Seals movement of the Plunger Rod
• Locations
• Upper Casting (throat) of Pump
• Piston at base of Plunger Rod

Position of packings in the Body Casting and on
the Plunger Rod
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Packing Types

• V packings for medium or high viscosity fluids
  (lt1,000 cP)
• Cup packings for low viscosity fluids (gt1,000
  cP)

Complete Spring/Packing Assembly, with V
packings
Cup Packing Assembly on Plunger/Piston
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Tube and Plunger

• The Plunger moves within the Tube
• The Plunger transfers fluid from the inlet to the
  pumps outlet

Plunger Rod (with Packing Assembly) and Tube
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Springs

• Compensate for normal wear of the packings caused
  by pump usage
• Coil Springs are used to pump lighter viscosity
  fluids
• Wave Springs offer excellent service in hard-duty
  use

Coil Spring Wave Spring
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Wet-Cup

• Helps prolong service life of throat packings
• Keeps Plunger Rod wetted as it reciprocates
• Prevents fluid from drying on Plunger Rod
• Wet-Sol keeps Plunger Rod wetted

Typical Wet-Cup Assembly
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Application 1 Basic Pump

• 650133-1 pulls fluid from 55-gallon drum
• Specifications
• 21 Ratio
• 18-Gallons per Minute
• Stainless Steel lower pump material

Pump mounts directly into bung opening of drum
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Application 2 Two-Ball Pump

• 650453-9 used to transfer oil from bulk tanks
• Specifications
• 91 Ratio
• 2.9-Gallons per Minute
• Carbon Steel lower pump material

Pump transfers oil from elevated tank to assembly
line in manufacturing facility
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Application 3 Chop Check Pump

• 650863-C4D-B in automotive assembly plant
• Specifications
• 451 Ratio
• 5.4-Gallons per Minute
• Carbon Steel lower pump material

Second pumping system is insurance policy in case
of pump failure
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Application 4 Chop-Check Pump

• 650239 Cart-mounted pump used in screen door
  assembly
• Specifications
• 91 Ratio
• 4-Gallons per Minute
• Carbon Steel lower pump material

Pump draws material from 5-gallon drum
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Application 5 Oil Pumps

• LM2305A-31 used in mobile oil-change system
• Specifications
• 51 Ratio
• 6-Gallons per Minute
• Carbon Steel lower pump material

Oil pumps mounted in back of van
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ARO and its Competitors

• Graco
• Broad pump line
• Lincoln
• Complete pump line
• Alemite
• Lubrication pumps

Lincoln extrusion pump
Alemite oil pump
Graco extrusion system
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ARO Crossover Program

• List competitive model number
• ARO provides model for application

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Pump Selection Checklist

• Basic data to make an initial pump selection
• Use this data, the ARO fluid compatibility guide
  and the pressure drop calculations to make an
  initial pump selection

Fluid Parameters Required Flow__________ Fluid
Viscosity__________ Plumbing Data Internal
Diameter_______ Piping Length__________ Inlet
Piping Length______ Air Inlet Pressure at
Pump_______ Application Data Continuous
Duty________ Intermittent Use________
If you feel uncertain about your pump selection,
call Aro for help!
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Refuse to Lose!
Refuse to Lose!
Add the fries