Figure: POM pilot installation at the Albbruck PM 7 paper machine
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POM Technology
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The POM Concept is a system for reducing the volume of the thin stock loop of a paper machine. The original intention of the system was to make grade changes more quickly, but the technique has proved to have benefits beyond this. Because of the smaller volume of white water, and the consequent shorter time to turn it over, upsets (for instance to wet end chemistry) can be dealt with faster; equilibrium is attained quickly. Also, because of the high velocity and low air content of stock in the system, cleanliness is improved. The smaller amount of white water handled reduces the load in the saveall.
The key component of the system is the "POMp", a thin stock pump that includes a centrifugal dewatering section. The "POMp" picks up water from the machine trays and vacuum box sumps, and delivers it back to the cleaner fan pump. Because the "POMp" does a thorough job of removing air, it is not necessary to have a white water pit or silo with large volume and low flow rate to allow entrained air to escape. This part of the system has been demonstrated at MD-Albbruck Papier (see below).
A second step, which has not been demonstrated yet, is the elimination of the mix tank and machine chest, and the installation of a "POMix" processor. This is a tall mixing tube with an agitator in the funnel shaped upper end. The thick stock furnish components (including broke) are fed into the top of the "POMix" at up to 5% consistency, and are completely blended at the bottom where they are fed to the suction of the cleaner fan pump. Time delay from mixing to the headbox is about 30 seconds.
For handling wet broke, another untried device, the "POMit" homogenizer, handles the broke at high consistency. This avoids the need for a broke thickener and reduces water use during breaks. The "POMit" is essentially two kneading rolls.
The contact is:
Paul Olof Meinander
POM Technologies
Tel: 358-9-751-75210
Fax: 358-9-751-75250
| Process Volumes | Old System | Pilot | POM Concept |
|---|---|---|---|
| Wire-water pit | 50 | 5 | 1 |
| Suction-water pit | 20 | 20 | 0 |
| Second screen feeding tank | 10 | 10 | 2 |
| Third stage cleaner feeding tank | 18 | 18 | 0 |
| POMps, including feeding | 0 | 1 | 2 |
| Deculator plant | 10 | 0 | 0 |
| Pipes | 15 | 13 | 4 |
| Pressure screens | 3 | 3 | 3 |
| Cleaners | 4 | 4 | 3 |
| Headbox, including feeding | 7 | 7 | 5 |
| Total | 137 | 81 | 20 |