US 4,712,472 A · Method of and apparatus for altering the moisture content of running webs

Abstract

A running web which contains moisture is caused to travel through the nip of two squeezing rollers one of which is deformable in that it comprises a stationary carrier and a cylindrical shell which surrounds the carrier and also surrounds a first set of inflatable cushions adjacent the nip and a second set of inflatable cushions opposite the first set. Sensors monitor the moisture content of selected longitudinally extending portions of the web, and the signals which are generated by such sensors are processed by an evaluating circuit and are transmitted to valves which regulate the pressure of pneumatic fluid in the cushions. Each cushion of the second set registers with a cushion of the first set, and the registering cushions can receive fluid from associated sets of valves including a pressure regulating valve which can increase or reduce the pressure of fluid in the respective cushions and a second valve which can shift the admission of fluid from one into the other of the registering valves. If the moisture content of a marginal portion of the web is to be increased, the pressure in the corresponding cushion of the first set is reduced gradually to zero, and if this does not suffice to increase the moisture content to a desired value, the pressure in the corresponding cushion of the second set is increased so that the respective end portion of the shell of the deformable squeezing roller is actually pulled away from the nip.

Claims20

Dependent claims

A method of altering the moisture content of a running web of textile or like material in the elongated nip of two squeezing rollers at least one of which is deformable so as to allow for changes in the width of the nip, comprising the steps of monitoring the moisture content of a plurality of web portions which are spaced apart from each other in the longitudinal direction of the nip and each of which is in line with a different portion of the one roller;

individually biasing said portions of the one roller toward the other of the rollers so as to exert pressure upon the corresponding portions of the web;
comparing the monitored moisture content with predetermined reference values and generating signals denoting deviations of monitored moisture content from the respective reference values;
reducing the bias upon a selected portion of the one roller, with attendant increase in the moisture content of the corresponding portion of the web, when the respective signal denotes insufficient moisture content;
and biasing the selected portion of the one roller away from the other roller by increasing the pressure upon a further selected portion of said roller substantially on the opposite side of said selected portion when the bias upon the selected portion is reduced to zero but the moisture content of the corresponding portion of the web is still below that which is denoted by the respective reference signal.

1 more element

Apparatus for altering the moisture content of a running web of textile or like material, comprising first and second squeezing rollers defining an elongated nip for the web, at least one of said rollers having a stationary carrier, a deformable rotary shell surrounding said carrier, a first set of inflatable cushions between said carrier and said shell adjacent said nip, and a second set of inflatable cushions between said carrier and said shell opposite the cushions of said first set;

monitoring means including sensors arranged to determine the moisture content of a plurality of web portions which are spaced apart from each other in the longitudinal direction of the nip and are in line with the cushions of said first set, and to generate signals denoting the monitored moisture content;
a source of pressurized pneumatic fluid;
means for connecting said source with said cushions;
and means for regulating the pressure of fluid in said cushions as a function of said signals, including means for controlling the flow of fluid between said source on the one hand and at least one cushion of said first set and the corresponding cushion of said second set on the other hand in response to signals from the sesnsor in line with said one cushion, said controlling means including means for reducing the pressure in the one cushion of said first set when the respective signal denotes that the moisture content of the corresponding portion of the web is below a predetermined value and for increasing the pressure in the corresponding cushion of the second set when the pressure in the one cushion of the first set is reduced to zero but the moisture content of the corresponding portion of the web is still below the predetermined value.

1 more element

Dependencies are inferred from the claim text.

Method of and apparatus for altering the moisture content of running webs

Life of this patent

Method of and apparatus for altering the moisture content of running webs

Life of this patent

Abstract

Claims20