This is the third piece of papermaking laboratory equipment I have for sale. Per ISO standard 5267-1, this tests the “freeness” of the pulp, which can be thought of as the amount of water which is “free” and will drain quickly from the fibres. As pulp is beaten (for instance in a Hollander beater) its freeness decreases. This instrument is one of two commonly used to test for pulp freeness, the other being a Canadian Standard Freeness (CSF) tester. There are tables to convert between S-R freeness and CSF freeness.
Both testers run on similar principles: A known amount of pulp is released to drain through a screen, and the drain water is directed to a funnel which has one hole at the bottom which allows a known flow rate, and another side hole to catch any water that drains from the pulp in excess of that rate. The volume of water from the side hole is measured to give an indication of how much of the water in the pulp is free to drain quickly.
Unfortunately this tester is in storage and I have no photos of it, but it is essentially the same as the one illustrated here. There is a weight in the larger vertical tube at the back, and a cord leading to the pulley and crank at the top. When a catch is released, the weight drops, lifting the bar and allowing the pulp in the upper chamber to reach the screen. By using a weight like this the test is not affected by the manner in which the operator releases the pulp. To give you an idea of the overall size, the tester is about 1m tall, and the upper cylinder holds 1L of pulp.
The tester for sale is complete and suitable as is to obtain qualitative results but would require calibration for quantitative results that could be sensibly compared with the results from other S-R testers.
We are asking $1000 for this unit.