STABILIZE THROUGHPUT WITH A PRECISION HARREL MELT PUMP AND SHEETROL(R) III
The final step in ensuring the quality of the sheet is to stabilize the throughput of the extruder by use of a precision Harrel melt pump, with the Harrel SHEETROL III control system.. Harrel was a pioneer in the application of melt pumps to the extrusion process and has been making its own precision melt pumps since 1979.
Harrel now offers a complete line of precision pumps, ranging in size from 0.014 cc/rev, up to 750 cc.rev. Special forms are aavailable for the extrusion of PVC and for fluoropolymers. You can't find a better melt pump than Harrel's!
When the SHEETROL III system is to be used with a Harrel extruder, as it is in a Harrel turnkey sheet extrusion system, , the melt pump can be mounted as an integral part of the extruder structure, thus converting the extruder into a GEARTRUDER(R). If the extruder is not of Harrel manufacture, the floor-mounted stands described below are used. In either case, the SC-873 SHEETROL I or SHEETROL II controller controls the melt pump in addition to its other functions.
- Stabilizes throughput of system to 0.1%, vs. perhaps 5% - 10% for an extruder used alone.
- Increases available output of system -- typically 15-25% or more.
- Less heat stress added to polymer, since melt pump is much more efficient than extruder alone. Melt temperature at die, thus can be lower with melt pump than with extruder alone.
- Can generate much higher melt pressures than extruder used alone.
- Total power consumption of both extruder and melt pump is almost always less than extruder used alone. There are thus savings in power costs.
DESCRIPTION OF COMPONENTS
-
The Melt Pump.The Harrel melt pump is not a unit originally designed for some other application. It was specifically designed for one-on-one service with precision extruders.
Precision helical gears eliminate the "tooth noise" which occurs with spur gear designs. Through-port construction and close fitting flanges eliminate dead spots, where plastic can hang up and degrade. Heating of the polymer is minimized by limiting the maximum speed to about 60 RPM.
- Mounting flanges. Ideally all you'd have to do to install a gear pump is to unscrew the die, move it a foot or so, drop in a gear pump, and bolt it back together again. Harrel furnishes mounting flanges to match your extruder and your die, with split clamps to hold it all together, so that's just about easy it is with a Harrel upgrade system!
- Gear Reducer. Motor and reducer sit right alongside the extruder on a convenient stand.
- Coupling. A double-knuckle coupling accommodates misalignment from the gear pump to the gear reducer. A single screw is all that is required to remove the coupling. A shear pin protects the pump.
- Controllers. The only major source of error in a melt pump is the incidental leakages around the gears. These leakages are proportional, not to the inlet pressure, but rather to the differential pressure across the pump. The Harrel CP-873 DIGIPANEL(R) SHEETROL I or SHEETROL II controller controls this differential pressure and thus increases the overall stability of the pump system by a factor of 5 to 8.
- Motor and Digital Drive. The motor for the gear pump is a rugged DC motor with the all-digital MC-101H DIGISYNCH drive controller, synchronized to a 0.001% crystal reference, and a MD-200 power module.
Even more useful is the capability of the DIGISYNCH controller to synchronize the gear pump speed to the puller speed -- an exact synchronization -- 0.000% steady state error. This in turn stabilizes the cross sectional area of the extrudate.
PRICES
| Model |
For extruder |
Approx extr lbs/hr |
Gear Pump |
cc/rev
| Approx pump lbs/hr |
Pump HP |
Base Price* |
| SG-610A |
1" |
15 |
GP-0005 |
0.5 |
4 |
0.5 |
$15,000 |
| SG-610B |
|
|
GP-001 |
1 |
8 |
0.75 |
$15,000 |
| SG-610C |
|
|
GP-003 |
3 |
15 |
1 |
$15,450 |
| SG-612A |
1 1/4" |
30 |
GP-003 |
3 |
24 |
1 |
$16,000 |
| SG-612B |
|
|
GP-005 |
5 |
30 |
1 |
$16,350 |
| SG-615A |
1 1/2" |
55 |
GP-005 |
5 |
40 |
2 |
$17,000 |
| SG-615B |
|
|
GP-010 |
10 |
55 |
2 |
$20,360 |
| SG-620 |
2 |
110 |
GP-020 |
20 |
110 |
3 |
$21,750 |
| SG-625A |
2 1/2 |
215 |
GP-020 |
20 |
160 |
3 |
$21,750 |
| SG-625B |
|
|
GP-050 |
50 |
215 |
5 |
$24,990 |
| SG-635A |
3 1/2 |
400 |
GP-050 |
50 |
400 |
5 |
$24,990 |
*Includes melt pump with heaters, drive motor and gear reducer on mounting stand,two PS-301 pressure sensors,MD-200 series power module for melt pump motor, and addition of melt pump differential pressure control function and DIGISYNCH digital speed controller function to SC-873 SHEETROL controller.
OPTIONS AND ACCESSORIES FOR ALL SIZES>
1. Inlet and outlet flanges to mate melt pump to extruder and die -- $1720.
2. Added price for 3 zones of temperature control -- inlet flange, outlet flange, and melt pump. Includes PID control loops, temperature sensors, and solid state power modules -- $900
3. Added price for a second DIGISYNCH control function in SC-873 SHEETROL controller for synchronization of melt pump RPM to puller RPM -- 0.000% synchronization error. Stabilizes cross sectional area of extrudate -- $1100.
4. DIGITACH digital tachometer for puller drive motor, if required.
....DT-100 for 1/4 - 3 HP -- $525.
....DT-120 for 5 HP -- $985.
5. Gear pump mounting stand -- where additional support is required to support weight of melt pump and die -- $750.
ORDER SHEETROL III, OPTIONS, AND ACCESSORIES ON LINE
To order a SHEETROL III system, fill in the form below and click on "submit". Harrel will enter your order and send you an Email or Fax acknowledgement stating engineering data and credit information required, if any. Enter accessories and options as separate items 2, 3, 4,etc.
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Prices subject to change without notice