Paper forming consists essentially of removing water from a dilute suspension of fiber and other materials by filtration, leaving the solids in form of a coherent sheet on forming fabric. Clearly, the rate and separation effectiveness of this water removal from paper fiber webs through forming fabric is significant to the economy of the process of papermaking.
Water removal from fiber webs on the paper machine is a hydro-mechanical process and which is accomplished by a sequence of mechanisms, like the forming fabric, felt or screen for drainage and so forth. At the same time, during the papermaking the properties of the stock slurry and added chemicals also play a significant role in the water removal from paper fiber webs through forming fabric.
For productivity in addition to the paper quality control in the paper mill, consideration of stock drainage resistance is important. The “freeness” of a stock is an extremely sensitive determine of the refining status of both chemical and mechanical pulps. Being strongly relevant to the actual thickness of the wet and consequently the dried paper web, the freeness is often a widespread used method for the guess of paper characteristics. The paper industry thus has for a long period of time strongly felt the need for rapid drainage measurement methods.
Quite a few tries happen to be made to layout model systems or stock drainage behavior on the paper machine. The original research laboratory tests regarding predicting the and still most widely used drainage testers are the SR (Schopper Riegler) slowness (or wetness) tester, and also the fairly more younger CFS (Canadian Standard Freeness) freeness tester. Over the years, quite a few various other drainage tests have been devised to further improve prophecy of water removal from paper fiber webs. It’s unlikely that any happen to be universally received. Even the traditional ones have doubtful reputation between quite a few scientists. They may nonetheless end up being very useful instrument if applied just for the purpose for which they were designed.