Waste paper, stock preparation I

Waste paper and pulpers

The waste paper bales or pulp bales are fed in via a conveyor to the pulper and repulped by adding process water. The pulper rotator (agitator) ensures the disintegration of waste paper fibres. Some systems process only one batch at a time, while others operate continuously, such as repulping drums used for waste paper.

Conveyor detection with VEGASON 62

The VEGASON 62 ultrasonic sensor detects if the paper loading height on the conveyor belt is exceeded, as well as any possible blockages thus ensuring reliable automation of the process.

Level measurement with VEGABAR 64

Accurate level measurement inside a pulper ensures the correct proportion of waste paper, i.e. pulp, to process water. The pressure transmitter VEGABAR 64 with rugged CERTEC measuring cell is used for this measurement. The instrument is always mounted on a socket inclined in rotation direction and equipped with a rinsing facility.

Level measurement with VEGABAR 65

VEGABAR 65 with metallic METEC measuring cell is implemented for level measurement in pulpers for filter and teabag paper with low pH value.

Efficient fibre separation in the pressurised screen

Any impurities bigger than the fibres must be separated out. For this purpose, the fibre suspension is pumped through a pressurised screen at a pressure of approx. 2 bar (29 psig) at approx. 50°C (122°F). The material flows in tangentially along the surface of rotating screen cylinders with holes or slots. The screening machines have an inlet, an outlet for good material (accept) and an overflow for sorted out material (reject). The separating efficiency is defined by the hydraulic pressure of the screen, the dimensions of the holes or slots and the quantity of reject.

Pressure measurement with VEGABAR 54 and VEGABAR 64

For effective screening, the machine must be run with the correct operating parameters. For this purpose, the pressure is measured at the inlet and discharge areas. For this measurement the pressure transmitter VEGABAR 64 with ceramic CERTEC measuring cell and process connection M44x1,25 is used. As an alternative, VEGABAR 54 with the small ceramic CERTEC measuring cell and process connection M30x1,5 is also available.
Further typical applications for VEGABAR 54 or VEGABAR 64 are level and pressure measurement on the cleaners, in the flotation tank and on the disc filters.

VEGASON 62

- non-contact and maintenance free measurement
- quick detection of the actual loading

VEGABAR 64

- high overload resistance against pressure shocks from falling bales
- highly resistant to abrasion by e.g. wire, sand and stones

VEGABAR 65

- flush CERTEC measuring cell
- self-cleaning
- highly vibration resistant
- with manometer adapter

VEGABAR 54

- front flush, selfcleaning
- highly abrasion resistant
- suitable even for narrow pipelines

VEGABAR 64

- front flush, selfcleaning
- highly abrasion resistant
- optional with manometer adapter