Zenith PEP-II User Manual
Zenith®Pumps
Installation,
Care and
Maintenance
Zenith
Polymer
Extrusion
Gear Pumps
PEP-II Series
Gear Pumps
Zenith®Pumps
2
Thoroughly read and understand this entire manual
before installation and operation of pump.
Benefits
Specifications
Capacities: 0.16 to 750 cc/rev.
Operating Speed: 10 - 90 rpm on most extrusion processes depending upon
process parameters
Differential Pressure: Up to 5,000 psi (345 bar)
Body Pressure: 10,000 psi (690 bar).
Temperature: To 645° F (340° C),
(950° F maximum with special fasteners and seals).
In 1926, Zenith Pumps was approached
by the synthetic fiber industry to design a
pump to provide a precise, pulseless, and
repeatable flow and assure better quality
control.
Since then, Zenith has provided
pumps for virtually every polymer utilized
in the plastics extrusion industry. Over the
years, Zenith has continually developed
and improved its pump designs to meet
the stringent demands made by new
polymers and new processes.
Zenith Pumps' line of PEP-II polymer
extrusion pumps has a unique positive
displacement design, which provides consistent, accurate polymer delivery under
varying extruder output conditions of
pressure, temperature and viscosity.
These virtually pulseless gear pumps are
the ideal interface between the extruder
and the die of extrusion systems, and provide a homogeneous melt at increased
throughputs and tighter gauge tolerances.
For years, polymer processors have utilized
gear-pump-assisted extrusion to solve
critical issues in the diverse plastics
industry.
The Zenith gear pump optimizes the
extrusion process by allowing the screw
to melt and homogenize the polymer. As
the pump generates the needed pressure,
it relieves the extruder of work; therefore,
reducing heat from the shear, lowering the
torque required, and eliminating surging.
All this optimizes the performance of the
extruder and offers the following benefits:
• Improved Dimensional Stability—
Effectively isolates the die from
upstream fluctuations.
• Controlled Melt Quality—Regulates
the extruder back pressure while it
reduces residence time, stabilizes the
plasticating action, and lowers melt
temperature.
• Increased Production—Provides very
high efficiency regardless of its pres-
sure building requirement.
• Reduced Raw Material Usage—
Provides a narrower finished product
gauge variation.
• Eliminates Surging and Screw Beat—
Effectively handles problems caused
by melt density or extruder parameters.
• Increased Extruder Flexibility—
Allows varying process conditions
such as higher regrind levels, temperatures, pressures, etc.
• Crowned Root Gear Design—
Reduces shear internal to the pump,
lowering the temperature and increasing
the production rate per power required.
• Streamlined Operation and Start-up—
Closed-loop controls provide easy
operator interface.
• Extended Extruder Life—Reduces
work required by the extruder such as
pressure and torque.
• Lower Operational Costs—Provides
a more efficient method of conveying,
eliminating material giveaway, and
increasing production per pound of
extrudate, etc.
Zenith®Pumps and The Extrusion Process
Design
Zenith Pumps can handle all your extrusion pumping applications including
additive injection for on-line compounding of tackifiers, colorants, stabilizers, etc.
3
ZENITH
ADDITIVE
INJECTION
SYSTEM
ELECTRIC
HEAT PLATE
PUMP
TEMPERATURE
INLET
PRESSURE
DISCHARGE
PRESSURE
ZENITH
PEP-II
PUMP
CHANGER
P
P
T
EXTRUDER
The PEP-II pump is constructed of two
gears rotating in mesh within a closely fitted housing that is comprised of three
plates. The center, or gear plate, fits
closely around the outside diameter of the
metering gears and bearings. The front
and rear, or cover plates, sandwich the
center plate and restrict axial movement
of the gears and bearings. In capacities
of 5 cc/rev and larger, the driving gear is
manufactured integral with the drive shaft,
and the driven gear is machined integral
with its shaft. In capacities of 3.0 cc/rev
and below, the gears are keyed to their
respective shafts. In all capacities the
shafts are supported by “D” shaped
bearings which fit into the center plate. In
capacities of 40 cc/rev and above, these
bearings are located by two screws which
pass through the cover plates. In capacities
of 20 cc/rev and below, the bearings are
keyed to each other for accurate location.
Each cover plate is secured to the
center plate by 10 screws (6 screws for
below 5 cc/rev). Each side of the center
plate has a circular port in the center of a
bolt circle for the mounting of adapter
flanges that fit the pump to your equiment.
Threaded holes are provided on the top
and bottom of the center plate for the
mounting of heat plates and for the
mounting of the pump to its stand.
Thermocouple wells (1/8-27 NPT) are
located on the body of the pump.
A Zenith Rheoseal assembly secured
to each cover plate (front cover plate only
on 3.0 cc/rev and below) prevents leakage
around the shaft, using both dynamic and
static types of sealing mechanisms. A
Rheoseal consists of a helical groove on
the inner diameter, a cooling jacket and a
static, backup seal counter bore and
gland. These spiral grooves allow the
Rheoseal to act as a screw-type pump.
As the fluid attempts to leave the gear
pump, the shaft's rotary motion forces the
fluid into the grooves. This creates a pressure greater than the pressure forcing
polymer out of the pump, thus returning
the polymer back towards the pump.
Since the rotary motion is required of the
shaft, two other static types of seals are
employed on the Rheoseal—a spring
energized lip-seal or a packing seal
secured by the gland. Also a flushing
cooling jacket surrounds a portion of the
grooved seal. Use of the cooling jacket
may be required for effective sealing if the
viscosity is below 1,000 poise at process
conditions. If used, water passing through
the housing cools the polymer, increasing
the effectiveness of the seal's pumping
action. A thermocouple well is provided
in the seal housing to allow for measuring
the temperature close to the region where
sealing actually occurs.
A complete line of accessories is
available and includes heating plates
(electric, oil and steam), adapter flanges,
mounting blocks and pump drive systems
complete with power package controls
and process controls. Please contact
Zenith or your local Zenith representative
for further information.
PEP-II Pump
0.16-3 cc/rev
ITEM QTY PART MATERIAL
1 1 FRONT PLATE TOOL STEEL
2 1 CENTER PLATE TOOL STEEL
3 1 REAR PLATE TOOL STEEL
4 1 DRIVE SHAFT TOOL STEEL
5 1 ARBOR TOOL STEEL
6 2 METERING GEAR TOOL STEEL
8 2 KEY, GEAR
9 2 BEARING TOOL STEEL
10 2 BEARING TOOL STEEL
11 1 RHEOSEAL STAINLESS
13 1 SEAL PLATE STAINLESS
14 1 LIP SEAL FILLED PTFE
15 6 SOCKET HEAD BOLT ALLOY
16 4 SOCKET HEAD BOLT ALLOY
17 4 SOCKET HEAD BOLT ALLOY
18 2 METAL C-RING, PORTS
19 2 KEY, D-BEARING
20 1 KEY, EXTERNAL
PUMP PUMP DIMENSIONS MAX APPROX
CAPACITY A B C D E F G H I J TORQUE WEIGHT
0.16 3.000 3.000 2.860 1.400 2.400 1.960 0.750 1/4 1.500 0.125 80 9
0.3 3.000 3.000 2.860 1.400 2.400 1.960 0.750 1/4 1.500 0.125 80 9
0.6 3.000 3.000 2.860 1.400 2.400 1.960 0.750 1/4 1.500 0.250 195 9
1.2 3.000 3.000 3.650 1.400 2.400 1.960 0.750 5/16 2.500 0.750 410 9
1.8 3.000 3.000 3.650 1.400 2.400 1.960 0.750 5/16 2.500 0.750 410 9
3.0 3.000 3.000 3.650 1.400 2.400 1.960 0.750 5/16 2.500 1.000 600 9
CC/REV PUMP DIMENSIONS ARE IN INCHES IN-LBS LBS
Materials Of Construction Diagram And Chart
Diagram 2 Chart 2
Chart 1
Dimensional Data Chart
Diagram 1
Dimensional Diagram
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