Est. 1998 — 27 years of woodworking knowledge
Tuesday Trivia
Bill Earl
At the 'wet end' of a paper mill, the watery pulp is sprayed out into a continuous sheet. At this point in the process, the paper is about 90% water.
There are several steps in the process were water is removed. What is the first step? Wood used to play an essential role here - although it has been largely replaced by more high-tech solutions.
I'll start
Gary Smyth
If I understand the wet pulp is loose. I'm thinking that the first step is it has to be squeeged so the pulp drys. In Japan they use a sieve and slow rolling with a wood cylinder for custom paper. On big presses today they use screens and hot air.
Re: Tuesday Trivia
Thomas Skaggs, Foothills of Mount Level
They have monkeys perched above the pulp aiming wooden hair dryers. Now the old wooden hair dryers have been replaced with plastic ones. It was a Union issue with the monkeys.
T.
Hint
Bill Earl
As both Gary and Tom have suggested, air is involved - although not heated air (and not administered by monkeys).
The wooden devices used in this process have been largely replaced by ceramics and plastics.
Re: Hint
Gary Smyth
If I have to get rid of moisture and the sprayed pulp is on a table/screen/mat, and not heated air let me guess a suction box as the screen passes above to pull the water out.
Re: Hint
Thomas Skaggs, Foothills of Mount Level
Big ol' wooden fans?
Correct Tuesday Answer
Bill Earl
As Gary correctly answered, the first de-watering step is a suction box. The pulp is sprayed out on a screen which is pulled across a series of chambers with a perforated surface where centrifugal blowers create a vacuum.
The action of the screen and paper fibers moving across the surface of the suction-box is quite abrasive. So the perforated plates (called "Suction Box Covers") were made from wood so that they could be easily and economically replaced.
Modern suction box covers are made from ceramics (expensive, but very resistant to abrasion) or low-friction plastics (less expensive and less durable, but energy efficient too).
After the suction boxes, the water is further squeezed out with rollers before moving on to warm air dryers.