Zenith® PEP-II
Series Gear Pumps -
Precise, Pulseless, Repeatable Performance in Polymer Applications Applications
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In 1926, Zenith Pumps developed the first precision metering
gear pump for the extrusion of acetate rayon. This basic design became the foundation for
the entire synthetic fiber industry.
During the '40s and '50s, Zenith Pumps developed the original
PEP (Polymer Extrusion Pump) design for the extrusion of film, sheet and profile, which
consisted primarily of polyester and nylon polymers.
Since then, Zenith has provided pumps for virtually every
polymer utilized in the plastics industry. This diverse experience has resulted in the
development of many design features and modifications for the PEP-II pumps.
The PEP-II's unique positive displacement design provides
consistent, accurate polymer delivery under varying extruder output conditions of
pressure, temperature and viscosity. With the PEP-II providing the pressure between the
extruder and the die, extruder parameters can be configured to provide a homogeneous melt
at increased throughputs and tighter gauge tolerances.
Today, the Zenith PEP-II pump has become the pump of choice
for a wide range of polymer applications in the plastics industry. Zenith can be found
wherever precise, pulseless, repeatable metering of fluids is required.
Benefits
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 of 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 pressure 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 Startup - 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.
Applications
| Film |
Profile |
Wire & Cable |
Tubing |
Fiber |
| Sheet |
Coextrusion |
Nonwoven |
Coating |
Boosting |
| Pelletizing |
|
|
|
|
Examples of materials processed include:
| Acrylic |
Hot Melt Adhesive |
PC |
PUR |
PEEK |
HIPS |
ABS |
| Cellulosics |
Fluoropolymers |
PE |
PP |
PVC |
PMMA |
SMA |
| Polysulfone |
LLDPE |
PS |
PA |
PCA |
PVB |
TPEs |
| Polyester |
HDPE |
PB |
PET |
SAN |
PIB |
Many others |
Pump Capacity
Capacity
cc/rev |
Flow Rate
lbs/hr |
Extruder Size
in. |
Typical Drive
HP |
Capacity
cc/rev |
Flow Rate
lbs/hr |
Extruder Size
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 |
Specifications
-
Capacities: From less than 1 to more than 7,000 lbs/hr standard.
- Operating Speed: See below: Depending upon process
parameters
- Pressures: Body to 10,000 psi (690 BAR); differentials
up to 4,000 psi (276 BAR).
- Temperature: To 950°F (510°C).
Capacity
cc/rev |
K1 |
K2 |
Max.
Torque
in./lbs. |
| 0.16 |
0.0016 |
0.00332 |
80 |
| 0.3 |
0.0029 |
0.00332 |
80 |
| 0.6 |
0.0058 |
0.00355 |
195 |
| 1.2 |
0.0117 |
0.00459 |
410 |
| 1.8 |
0.0175 |
0.00507 |
410 |
| 3.0 |
0.0291 |
0.00597 |
600 |
| 5.0 |
0.0484 |
0.00342 |
1,225 |
| 10.0 |
0.0971 |
0.00706 |
2,085 |
| 20.0 |
0.1942 |
0.01172 |
3,250 |
| 40.0 |
0.3883 |
0.01919 |
6,750 |
| 100.0 |
0.9708 |
0.04328 |
12,100 |
| 175.0 |
1.6990 |
0.08113 |
22,400 |
| 300.0 |
2.9126 |
0.15357 |
50,600 |
| 750.0 |
7.2816 |
0.37911 |
116,600 |
|
Technical
Data
Required Torque: (IN-LB)
Torque= (K1 Delta-P) + (K2 N µ)
K1 = Constant from chart
N = Rev. per minute
Delta-P = Differential pressure (psi)
K2 = Constant from chart
µ = Viscosity in Poise at application's maximum shear rate
|
 Maximum Pump
Speed
PEP-II Pump
0.16-3 cc/rev
 |
Dimensional Diagram
 |
Dimensional Data Chart
Pump
Capacity |
Pump Dimensions |
Max
Torque |
Approx.
Weight |
| A |
B |
C |
D |
E |
F |
G |
H |
I |
J |
| 0.16 |
3.000 |
3.000 |
2.860 |
1.400 |
2.400 |
1.960 |
0.750 |
¼ |
1.500 |
0.125 |
80 |
9 |
| 0.3 |
3.000 |
3.000 |
2.860 |
1.400 |
2.400 |
1.960 |
0.750 |
¼ |
1.500 |
0.125 |
80 |
9 |
| 0.6 |
3.000 |
3.000 |
2.860 |
1.400 |
2.400 |
1.960 |
0.750 |
¼ |
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
 |
| 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, port |
Not
shown |
| 19 |
2 |
Key,
d-bearing |
|
| 20 |
1 |
Key,
external |
|
|
PEP-II
Pump
5-750 cc/rev
 |
Dimensional
Diagram
 |
Dimensional Data Chart
Pump
Capacity |
Pump Dimensions |
Max
Torque |
Approx.
Weight |
| A |
B |
C |
D |
E |
F |
G |
H |
I |
J |
| 5 |
3.250 |
3.250 |
3.250 |
1.125 |
2.875 |
2.125 |
0.500 |
¼ |
1.875 |
0.750 |
1225 |
10 |
| 10 |
4.000 |
4.000 |
4.000 |
1.188 |
3.375 |
2.615 |
0.625 |
5/16 |
2.344 |
1.000 |
2085 |
18 |
| 20 |
4.750 |
5.000 |
5.000 |
1.188 |
3.750 |
3.300 |
0.750 |
3/8 |
2.813 |
1.250 |
3250 |
34 |
| 40 |
5.750 |
6.000 |
6.250 |
1.1888 |
4.438 |
4.000 |
1.000 |
7/16 |
3.531 |
1.500 |
6750 |
61 |
| 100 |
8.000 |
8.250 |
8.250 |
1.750 |
5.438 |
5.458 |
1.250 |
5/8 |
4.688 |
2.188 |
12100 |
150 |
| 175 |
9.500 |
9.750 |
9.880 |
1.813 |
6.375 |
6.475 |
1.500 |
3/4 |
5.750 |
2.625 |
22400 |
260 |
| 300 |
11.250 |
12.000 |
12.500 |
2.375 |
8.063 |
8.000 |
2.000 |
7/8 |
7.063 |
3.000 |
50600 |
480 |
| 750 |
14.750 |
15.750 |
16.500 |
3.000 |
10.000 |
10.542 |
2.500 |
1 1/8 |
9.688 |
4.250 |
116600 |
1100 |
| cc/rev |
Pump Dimensions are in Inches |
In.-lbs. |
lbs. |
Materials of Construction Diagram
and Chart
 |
| Item |
Qty |
Part |
Material |
| 1 |
1 |
Driving gear shaft |
Tool Steel |
| 2 |
1 |
Driven gear shaft |
Tool Steel |
| 3 |
1 |
Center plate |
Tool Steel |
| 4 |
2 |
Cover plate |
4140 |
| 6 |
2 |
Bearing |
Tool Steel |
| 7 |
2 |
Bearing |
Tool Steel |
| 14 |
2 |
Seal plate |
Stainless |
| 16 |
2 |
Lip seal |
Filled PTFE |
| 17 |
20 |
Socket head bolt |
Alloy |
| 18 |
8 |
Socket
head bolt |
Alloy |
| 19 |
8 |
Hex
head bolt |
Alloy |
| 20 |
2 |
Rheoseal |
Stainless |
| 21 |
2 |
Socket
head cap screw |
Alloy |
| 22 |
2 |
Metal
c-ring, seals |
|
| 23 |
2 |
Metal
c-ring, ports |
Not
shown |
|
Zenith Pumps and the Extrusion Process
 Complete
Systems Capability -
Zenith Pumps offers typical drive and control packages, as well as custom systems designed
to meet your particular process specifications. Our extensive experience and full
engineering capabilities ensure you the best possible solution to your precision extrusion
application.
Zenith's typical extrusion control package provides the basic
controls for a PEP-II pump system. The drive consists of a motor and reducer mounted on a
common base plate, with speed controlled by a Zenith ZeTROL digital speed controller. A
pressure control system regulates the extruder speed and maintains a constant pressure to
the pump inlet. A temperature controller regulates the pump's electric heaters.
Other features available include:
- Discharge pressure indicator
- Pump inlet/discharge flanges
- Pump fluid or steam heat plates
- Bronze heat plates for extreme service
- System mounting carts
- Start-up assistance
PEP-II Series Gear Pumps with Rheoseal
|
