Zenith® PEP-II Series Gear Pumps with Rheoseal

PEP-II Series with Rheoseal
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Application Polymer
LDPE PS PP PVC HDPE PUR PA PET
Sheet X X X X X X   X
Profile X X X X X X   X
Film X X X   X   X X
Coextrusion X X X X X X X X
Tubing X X   X X X   X
Additive Injection X X X X X X X X
Nonwovens X   X       X X

Approximate Pump / Drive Sizing

PEP-II
Capacity
(cc/rev)		 Typical
Flow Rate
(L/hr)		 Typical
Extruder
(in.)		 Typical Drive
(HP)		 PEP-II
Capacity
(cc/rev)		 Typical
Flow Rate
(L/hr)		 Typical
Extruder
(in.)		 Typical Drive
(HP)
0.16 0.2 - 1.25 .25 0.5 10 13 - 80 1.0, 1.25, 1.5 2
0.3 .04 - 2.5 .25, .5 0.5 20 26 - 160 1.25, 1.5, 2.0 3
0.6 .8 - 5 .5 0.5 40 53 - 450 1.5, 2.0, 2.5 5
1.2 1.5 - 9.0 .5 0.5 100 250 - 1200 2.5, 3.5 10
1.8 2.4 - 14 .5 0.5 175 450 - 2100 3.5, 4.5 15
3 4 - 24 .75, 1.0 0.5 300 800 - 3600 4.5, 6.0 20
5 6 - 40 1.0 1 750 2000 - 7000 8.0 30

Design Features

  • Unique gearing
  • Rheoseal standard
  • Tool steel construction
  • Forced lubrication
  • 10,000 psig max. body pressure
  • 950°F max. operating temperature
  • Flanged connections

Process Benefits

  • Improved gauge stabilityZenith Pumps & the Extrusion Process
  • Controlled melt quality
  • Increased production
  • Improved extruder flexibility
  • Polymer material savings

Zenith Pumps can handle all your extrusion process applications including additive injection for on-line compounding of tackifiers, colorants, stabilizers, etc.

Experience

Zenith Pumps has been leading the way in gear pump technology since 1926. The PEP-II line is the result of years of practical, in-process research with Fortune 500 companies in tubing, sheet, film, nonwovens, coextrusion and profile installations. The PEP-II pump incorporates several major pump features that ensure better performance and consistent quality.

Crowned-Root Gears

Crowned Root vs Conventional gearsCrowned-root, low-aspect ratio gears reduce the temperature rise across the pump and improve gauge stability while preserving the mechanical properties of the polymer. The L/D ratio provides a shorter distance for the polymer to travel, therefore reducing shear. The crowned-root system increases the evacuation area of the gear root, reducing pressure pulse per tooth over conventional gears.

Rheoseal Design

The Rheoseal design included reverse flights inside the seal chamber, as well as a water channel to cool the polymer and a backup lip seal. The rotating shafts create a mechanical action on the material, which pumps the polymer back into the pump cavity and seals the shaft from leakage.

Materials of Construction

Material Wear ResistancePEP-II pumps are constructed of through-hardened materials with a minimum of Rc 60. These materials include CPM-M4 (Crucible Particle Metallurgy), M4 and M2 for wearing components. CPM parts have a finer grain size, better toughness and superior grind ability in the heat treated condition.

Positive Lubrication

The PEP-II pump's enhanced lubrication design utilizes the natural flow patterns of the pump so that forced lubrication occurs. When the collapsing teeth displace the metered amount of material, a high-pressure condition forces the material through the bearing areas, ensuring proper lubrication. Once the material flows to the back side of the bearing, it is channeled to the low pressure side of the pump and back into the melt stream.