The Study On A New-type On-line Porosity Measuring System

Tipping paper with micro perforation is an important material for the cigarette manufacturing industry, it can reduce the nicotine and condensate levels for filter cigarettes. Porosity measuring of porous and/or perforated (with laser or electrostatic perforation systems ) web material which are produced in speed ranges up to 600 m/min and web widths up to 2000 mm are difficult with pneumatic systems because these methods includes disadvantages such as web tangency, web toughing, material flaking, dust and dirt flowing in the system. These difficulties are ideally overcome with stationary, optical porosity measurement systems. In recent years, with the emphasis on human health and environment protection, optical on-line porosity measuring technology is increasingly important.This dissertation is mainly devoted to the design, experimental and theoretical study of a new-type optical on-line porosity measuring system, this system includes light unit, optical multisensors array, driving units, computer, etc. It can effectively attain high-precision porosity value.This dissertation consists of following four parts:The dissertation starts with a brief description of typical tipping paper porosity measuring system, the recent progresses of the porosity measuring technology are reviewed, and a brief introduction concerning the dissertation work is given.In part two, the design idea and mechanism of optical on-line porosity measuring system is put forward and the system construction for Yu-xi Tipping Paper Factory is described in detail. The characteristics of various components used in the system, such as photosensor, optical source, stepper motor, compressing air unit, etc, are discussed, the types of these components are selected. To eliminate temperature effect on measuring precision, a new idea about temperature-compensated technique is put forward in this dissertation, and used in the system. The software used in the porosity measuring system is designed.In part three, the tests that some factors effects the system measuring precision are carried out, these factors include environment temperature and moisture, paper speed, sensor sensitivity, etc. The problems appearing during the experiment procedures are analyzed and discussed, some improvement ways are presented.Finally, the achievement and conclusions of this dissertation are summarized, and some suggestions for the forward work are presented.