US5853543A — Method for monitoring and controlling water conte…

Claim 1

Independent Claim 331 words

A method of predicting the dry stock weight of a sheet of material that is on a moving water permeable fabric of a de-watering machine that includes a dryer section located downstream from the water permeable fabric said method comprising the steps of: a) placing three or more water weight sensors adjacent to the fabric wherein the sensors are positioned at different locations in the direction of movement of the fabric and placing a sensor to measure the dry weight of the sheet material after exiting the dryer section; b) operating the machine at predetermined operating parameters aid measuring the water weights of the sheet of material at the three or more locations on the fabrics with the water weight sensors and simultaneously measuring the dry weight of a part of the sheet of material exiting the dryer section; c) performing bump tests to measure changes in water weight in response to perturbations in three or more operating parameters wherein each bump test is performed by alternately varying one of the operating parameters while keeping the others constant, and calculating the changes in the measurements of the three or more water weight sensors and wherein the number of bump tests correspond to the number of water weight sensors employed; d) using said calculated changes in the measurements from stop c to obtain a N×M matrix that expresses changes in the three or more water weight sensors as a function of changes in the three or more operating parameters about the predetermined operating parameters wherein N is equal to the number of water weight sensors employed and M is equal to the number of bump tests performed and N is equal to or greater than M; and e) developing an inverted N×M matrix that provides the predicted dry weight for a segment after being dried in the dryer section based on measurements from the three or more water weight sensors for said segment of the sheet of material on the moving fabric.

Claim 2

Independent Claim 331 words

A method of predicting the dry stock weight of a sheet of material that is on a moving water permeable fabric of a de-watering machine that includes a dryer section located downstream from the water permeable fabric said method comprising the steps of: a) placing three or more water weight sensors adjacent to the fabric wherein the sensors are positioned at different locations in the direction of movement of the fabric and placing a sensor to measure the dry weight of the sheet material after exiting the dryer section; b) operating the machine at predetermined operating parameters aid measuring the water weights of the sheet of material at the three or more locations on the fabrics with the water weight sensors and simultaneously measuring the dry weight of a part of the sheet of material exiting the dryer section; c) performing bump tests to measure changes in water weight in response to perturbations in three or more operating parameters wherein each bump test is performed by alternately varying one of the operating parameters while keeping the others constant, and calculating the changes in the measurements of the three or more water weight sensors and wherein the number of bump tests correspond to the number of water weight sensors employed; d) using said calculated changes in the measurements from stop c to obtain a N×M matrix that expresses changes in the three or more water weight sensors as a function of changes in the three or more operating parameters about the predetermined operating parameters wherein N is equal to the number of water weight sensors employed and M is equal to the number of bump tests performed and N is equal to or greater than M; and e) developing an inverted N×M matrix that provides the predicted dry weight for a segment after being dried in the dryer section based on measurements from the three or more water weight sensors for said segment of the sheet of material on the moving fabric.

Claim 3

Dependent Claim 73 words

The method of claim 1 further comprising the step of measuring the water weight of the moving sheet with the three or more water weight sensors and simultaneously measuring the dry weight of a part of the sheet of material that has been dried in the dryer section and calculating the dry stock weight that the sheet of material that is on the fabric will be after being dried in the dryer section.

Claim 4

Dependent Claim 22 words

The method of claim 2 wherein each of the three or more water weight sensors is positioned underneath the water permeable fabric.

Claim 5

Dependent Claim 92 words

The method of claim 1 wherein the de-watering machine is a papermaking machine that comprises a forming section that includes the moving fabric and means for depositing an aqueous fiber stock comprising said material on a surface of the fabric, a plurality of de-watering mechanisms disposed sequentially underneath the fabric for removing water from said aqueous stock, wherein the step of performing the bump tests comprise varying the flow rate of the aqueous fiber stock onto the fabric, freeness of the fiber stock, or concentration of fiber in the aqueous fiber stock.

Claim 6

Dependent Claim 30 words

The method of claim 4 further comprising the step of changing one or more operating conditions of the papermaking machine in response to fluctuations in the calculated dry stock weight.

Claim 7

Dependent Claim 19 words

The method of claim 1 wherein the three or more water weight sensors that are positioned substantially in tandem.

Claim 8

Dependent Claim 80 words

The method of claim 1 wherein the step of placing three or more water weight sensors comprise (i) placing a water weight sensor adjacent to the fabric at a designated location on the fabric wherein substantially no solid stock material permeates through the fabric subsequent to the designated location and (ii) placing at least two water weight sensors on different locations on the fabric before said designated location as measured with respect to the direction of movement of the fabric.

Claim 9

Dependent Claim 22 words

The method of claim 1 wherein each of the three or more water weight sensors is positioned underneath the water permeable fabric.

Claim 10

Dependent Claim 24 words

The method of claim 1 wherein each of the three or more water weight sensors measures the water weight of the sheet of material.

Claim 11

Dependent Claim 13 words

The method of claim 1 wherein the sheet of material comprises paper stock.

Claim 12

Dependent Claim 11 words

The method of claim 1 wherein N is equal to M.

Claim 13

Independent Claim 270 words

A method of controlling the dry stock weight of a sheet of material that is on a moving water permeable fabric of a de-watering machine that comprises the steps of: a) placing three or more water weight sensors adjacent to the fabric wherein the sensors are positioned on different locations along the direction of movement of the fabric; b) operating the machine at predetermined parameters and measuring the water weights of the sheet of material with the sensors; c) performing bump tests to measure changes in water weights in response to perturbations in three or more operating parameters wherein each bump test is performed by alternately varying one of the operating parameters while keeping the others constant, and calculating the changes the measurements of three or more water weight sensors, wherein the number of bump tests corresponds to the number of sensors employed; d) using said calculated changes in the measurements from step C to obtain an N×M matrix that expresses changes in the three or more water weight sensors in response to changes in the three or more operating parameters about the predetermined operating parameters wherein N is equal to the number of sensors employed and M is equal to the number of bump tests performed and N is equal to or greater than M; e) inverting the matrix to derive a functional relationship which correlates changes in measurements from the three or more operating parameters to changes in the three water weight sensors; and f) employing said inverse function for controlling operation of the dewatering machine to produce a sheet of material having a desired dry stock weight.

Claim 14

Independent Claim 270 words

A method of controlling the dry stock weight of a sheet of material that is on a moving water permeable fabric of a de-watering machine that comprises the steps of: a) placing three or more water weight sensors adjacent to the fabric wherein the sensors are positioned on different locations along the direction of movement of the fabric; b) operating the machine at predetermined parameters and measuring the water weights of the sheet of material with the sensors; c) performing bump tests to measure changes in water weights in response to perturbations in three or more operating parameters wherein each bump test is performed by alternately varying one of the operating parameters while keeping the others constant, and calculating the changes the measurements of three or more water weight sensors, wherein the number of bump tests corresponds to the number of sensors employed; d) using said calculated changes in the measurements from step C to obtain an N×M matrix that expresses changes in the three or more water weight sensors in response to changes in the three or more operating parameters about the predetermined operating parameters wherein N is equal to the number of sensors employed and M is equal to the number of bump tests performed and N is equal to or greater than M; e) inverting the matrix to derive a functional relationship which correlates changes in measurements from the three or more operating parameters to changes in the three water weight sensors; and f) employing said inverse function for controlling operation of the dewatering machine to produce a sheet of material having a desired dry stock weight.

Claim 15

Dependent Claim 89 words

The method of claim 12 wherein the de-watering machine is a papermaking machine that comprises a forming section that includes the moving fabric and means for depositing an aqueous fiber stock on a surface of said fabric, a plurality of de-watering mechanisms disposed sequentially underneath the fabric for removing water from said aqueous stock, wherein the step of performing the bump tests comprise varying the flow rate of the aqueous fiber stock onto the fabric, freeness of the fiber stock, or concentration of fiber in the aqueous fiber stock.

Claim 16

Dependent Claim 22 words

The method of claim 13 wherein each of the three or more water weight sensors is positioned underneath the water permeable fabric.

Claim 17

Dependent Claim 37 words

The method of claim 12 wherein the functional relationship calculates the change in one or more of the operating parameters needed to produce a specified change in water content of the sheet of material on the fabric.

Claim 18

Dependent Claim 41 words

The method of claim 12 wherein the de-watering device comprises a dryer section located downstream from the water permeable fabric and a second sensor to measure dry stock weight of the sheet of material after being dried in the dryer section.

Claim 19

Dependent Claim 19 words

The method of claim 12 wherein the three or more water weight sensors that are positioned substantially in tandem.

Claim 20

Dependent Claim 80 words

The method of claim 12 wherein the step of placing three or more water weight sensors comprise (i) placing a water weight sensor adjacent to the fabric at a designated location on the fabric wherein substantially no solid stock material permeates through the fabric subsequent to the designated location and (ii) placing at least two water weight sensors on different locations on the fabric before said designated location as measured with respect to the direction of movement of the fabric.

Claim 21

Dependent Claim 22 words

The method of claim 12 wherein each of the three or more water weight sensors is positioned underneath the water permeable fabric.

Claim 22

Dependent Claim 24 words

The method of claim 12 wherein each of the three or more water weight sensors measures the water weight of the sheet of material.

Claim 23

Dependent Claim 13 words

The method of claim 12 wherein the sheet of material comprises paper stock.

Claim 24

Dependent Claim 11 words

The method of claim 12 wherein N is equal to M.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2001-12-28	2002-06-29	2002-12-29	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2005-12-28	2006-06-29	2006-12-29	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2009-12-28	2010-06-29	2010-12-29	$7700.00	Window Closed / Lapsed

Method for monitoring and controlling water content in paper stock in a paper making machine

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag