CA1223473A - Profiling air/steam system for paper-making machines - Google Patents
Profiling air/steam system for paper-making machinesInfo
- Publication number
- CA1223473A CA1223473A CA000436842A CA436842A CA1223473A CA 1223473 A CA1223473 A CA 1223473A CA 000436842 A CA000436842 A CA 000436842A CA 436842 A CA436842 A CA 436842A CA 1223473 A CA1223473 A CA 1223473A
- Authority
- CA
- Canada
- Prior art keywords
- steam
- paper
- air
- machine
- paper web
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F7/00—Other details of machines for making continuous webs of paper
- D21F7/003—Indicating or regulating the moisture content of the layer
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F3/00—Press section of machines for making continuous webs of paper
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Abstract
ABSTRACT OF THE DISCLOSURE
Method and apparatus are provided for effectively controlling cross-machine moisture profile in a paper web undergoing processing, such as water-removal via a press nip.
A compartmentalized system is provided in close proximity across a section of a traveling web undergoing dewatering whereby select size cross-machine compartments, for example, about 6"
in width, are selectively provided with steam and/or air so as to control wet and/or dry streaks along the traveling web so that web areas opposite each compartment can be selectively heated for accentuated moisture removal or cooled for retarded water removal. In preferred embodiments, control of this profiling system occurs with the aid of moisture sensors and a computer.
Method and apparatus are provided for effectively controlling cross-machine moisture profile in a paper web undergoing processing, such as water-removal via a press nip.
A compartmentalized system is provided in close proximity across a section of a traveling web undergoing dewatering whereby select size cross-machine compartments, for example, about 6"
in width, are selectively provided with steam and/or air so as to control wet and/or dry streaks along the traveling web so that web areas opposite each compartment can be selectively heated for accentuated moisture removal or cooled for retarded water removal. In preferred embodiments, control of this profiling system occurs with the aid of moisture sensors and a computer.
Description
1,~'234~73 _S P_E_G_I_~F_I_C A_T I O_N_ _T_I_T_L_E_ "PROFILING AIRISTEAM SYSTEM FOR PAPER-MAKING MACHI~ES"
BACKGROUND OF THE INVENTION
The invention relates to improved paper-making machines and somewhat more particularly to improved means for effective control of cross-machine moisture profile in a traveling paper web undergoing dewatering, as in a press section.
Prior Art Methods and mechanisms for applying steam to aid in dewatering a paper web are known, for example, see U. S. Patent No. 4,272,316 or U. S. Patent No. 4,163,688.
A presently accepted theory for this technique is that as a paper web or sheet is heated by applied steam, the viscos-ity of water insuch web is reduced, making water removal easier.
Recent developments in this area include compartmentalized steam boxes having separate cross-machine compar~ments allowing steam to be selectively applied in the cross-machine direction to a traveling web. Typically, such steam boxes are positioned about the outer surface of a suction roll so that steam can be drawn into th~ suction box and through the web supported by such roll.
The ability to correct or control the cross-machine moisture profile in a web has met with various degrees of success and problems still remain. One of such problems is that each com-partment cannot ~e readily sealed against the surface of the ~raveling web. One reason for this is that a minimum clea~nce of about 1" between the surface of the steam box and the suction ~ 223473 roll must be malntained in order to avoid damages from wads, wrap-ups, etc. With such large clearances, much of the applied steam in one compartment is frlee to migrate to adjacent compzrt-ments, with a resultant indiscriminate application of steam.
SUMMARY OF THE IN~ENTION
The invention provides a method and means which overcomes the prior art drawbacks and provides a more effective control of cross-machine moisture profile in a traveling paper web undergoing moisture removal in a paper-making machine.
In preferred embodiments of the invention, a compartmentalized system, such as in a chamber, is provided in working relation with a tra~eling paper web undergoing dewater-ing, as in a paper-making machine press section. This system includes a plurality of cross-machine profiling areas of compartments, each having valve-controlled means selectively supplying relatively dry air and/or steam to the web area associated with each profiling area.
In an exemplary embodiment of the inven~ion, a steam box having a plurality of cross-machine compartments is posi-tioned in close-running relation to a fluid-permeable means supporting a traveling web, typically a press nip defined by two press members, such as press rolls, one of which can be a grooved roll or a suction roll. The steam box is provided with a first cross-machine header, connected to a steam supply in the paper-making machine. Exiting from such header is a plur-ality of supply pipes and control valves, each associated with an individual compartment of the steam box. In addition, the steam bo~ is provided with a second cross-machine header~ con-nected to a compressed air source in a paper-making machine, ~ 2;~3473 with supply pipes and control valves associated therewith and with each individual compartment.
In preferred embodiments, a single valve means controls both the steam and air flow to an individual compartment. Each valve means can be interconnected to a computer and moisture sensors can be associated with select transverse areas of a traveling web and be interconnected to the computer so that the valves are appropriately activated by the computer for steam and/or air flow in accordance with the signal generated by the sensors.
In accordance with the principles of the invention, the air supply can be used to "flood" a compartment so as to prevent cross-machine migration of steam into that area.
Selectively supplying dry air to a select compartment of a steam box is further advantageous in that it can be utilized to con-trol dry areas of a sheet. As air is drawn into a sheet, evaporation cooling occurs, reducing the sheet temperature. At lower sheet temperatures, pressing is less effective. Hence, steam is supplied to control wet streaks in a sheet and air supply to control dry streaks in a sheet.
Other ob;ects, advantages and features as well as equivalent structures and methods which are intended to be covered herein will become more apparent with the teachings of the principles of the present invention in connection with the disclosure of the preferred embodiments thereof in the specification, claims and drawings, in which:
~1223473 BRIEF DESCR]:PTION OF THE DRAWINGS
FIG. 1 is a schemat:ic elevational p~rtial view illustrating a section of a paper-making machine constructed and operating in accordance ~ith the principles of the invention;
FIG. 2 is another somewhat similar schematic elevational view showing another form of the invention;
FIG. 3 is a partial somewhat schematic elevational view illustrating a steam/air box of the invention in association with a grooved press roll;
FIG. 4 is a partially broken-away top view illustra~ing one form of header arrangements utilized to supply air/steam to the airlsteam box of the invention;
FIG. 5 is an elevated detailed view cf a valve arrangement utilized to control steam/air in the air/steam box of the invention;
FIG. 6 is an elevated detailed view of an alternative valve arrangement utilized in the practice of the invention; and FIG. 7 is a schematic di.agram illustrating a working relation between a computer, moisture sensors and respective valve means of an air/steam box constructed and operable in accordance with the principles of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As illustrated in FIG. 1, a newly formed web W is carried on the upper surface of a traveling first endless felt, Fl, for example, from a Fourdrinier machine or from a first press section (not shown), into a psess nip Nl defined between ~.Z23473 a lower grooved roll 11 and an upper suction roll 12. A travel-ing second endless felt F2 is guided by guide rolls (not shown), so as to sandwich the web W between the felts Fl and F2 as they pass through the press nip Nl. At the press nip Nl, water is removed downwardly into the grooved roll G and from there to a saveall in a conventional manner. On the off-running side of the nip Nl, the web W adheres to the second felt F2 as this felt travels around the suction roll 12 in the manner shown. The first felt Fl is guided away fro~ the press nip Nl by a suitable guide roll and back through its endless loop in a conventional manner. The second ~elt F2, carrying the web W on its outer surface, travels around the suction roll 12 and past the suction gland 13 as illustrated. A profiling steam/air box 15 is posi-tioned in close working relation with the o~ter surface of the suction roll 12 so as to feed air or steam to select areas of the web via a controlled valve 15a connected to a steam source S
and to an air source A. The supplied steam and/or air streams penetrate through the felt F2 and into the web W and thence into the suction gland 13 of the suction roll 12 to effect tempera-ture control of the associated areas of the web. A plain-surfaced press roll 14 is positioned above suction roll 12 so as to define a second nip ~2. A third endless traveling felt F3 is guided over the surface of the plain press roll and against the web W so as to sandwich the web between the felts F2 and F3.
The so-sandwiched we.b is then carried away for further process-ing, for example, to another press section or to a dryer seetion of a paper-making machine.
FIG. 2 shows another press section wherein the profiling air/steam box of the invention is advan~ageously employed. In the embodiment here illustrated, a newly fo-rmed i223~73 web W is carried on a top surface of a first endless felt Fl into a first press nip Nl defirLed by an upper plain roll 23 and a lower grooved roll 22. Just prior to the press nip Nl, a compartmentalized profiling airlsteam box 21 is positioned in close running relation with the felt Fl so as to selectively feed steam and/or air upwardly through the felt Fl and into the web W via control valve 21a. At this location, steam aids water re~oval while dry air retards water removal so that steam can be supplied to control wet streaks in the newly formed web or sheet and air can be supplied to control the dry areas thereof.
After the press nip Nl, the felt Fl carries the web W into a second press nip N2 defined by a lower plain roll 24 and an upper suction roll 25 having a suction gland 25a. On the off-running side of the nip N2, the felt Fl is guided awa-; from the web W
back through its endless run via a plurality of guide rolls (not shown). The web W continues to adhere to the outer surface of the suction roll 25 because of the suction gland 25a. A
second profiling air/steam box 26 is positioned in close running relation with the outer surface of the suction roll in close conformity with the suction gland 25a and selectively feeds air or steam against the web surface via control valve 26a. Heated water is more readily withdrawn from the web via the suction gland whereas cooled water (cooled by supplied air) is somewhat more difficult to withdraw so that control of wet and/or dry streaks in the web W can be readily accomplished. A second endless traveling felt F2 is guided around a further plain press roll 27 positioned to define a further press nip N3 with the suction roll 25. On the off-running side of the nip N3, the felt F2 carries the web W on its undersurface away for further processing as desir~d, ~L2234~73 The profiling steamjair boxes of the invention, such as boxes 21 ~nd 26, correct cross-machine moisture profiles in webs undergoing dewatering. Each steam box is relatively fluid impermeable except for an open front face and is divided into a number of compartments in the cross-machine direction. Cross-machine headers are provided to supply compressed steam and air, respectively, to each compartment, which also includes an individual control valve. As is ~own, paper-making machines typically include a source of pressurized steam and may include a source of pressurized air. In any event, relatively dry air can be supplied from an external source by a fan or other suit-able means. A select air stream can be used to flood a compart-ment to prevent cross-machine migration of steam into the flooded compartment. Further, such dry air stream provides a means of controlling dry areas of a sheet since as air is drawn into a sheet, evaporation cooling occurs reducin~ the sheet temperature, making water removal less efficient. In this manner, dry areas can be controlled and by selectively applying steam to other areas, wet streaks can be controlled.
Referrin8 to FIG. 3, a grooved roll 35 having a plurality of grooves 35a is shown positioned in working relation wlth a profiling and/or steam box 30. The box 30 is provided with a back wall 31, an upper wall 32, a lower wall 33 and a forward open face 34, along with appropriate end walls (not shown), all joined to~ether in a relatively fluid-tight manner so as to be able to direct the steam and/or air flow toward the front face 34 of the bo~ 30. The walls are preferably formed from sheet mPtal and a plurality of individual compartments, for examp?e, a~out 6'l in width, are provided along the cross-machine di~ection of the box. For this purpose, a plurality of :iL223473 compartment walls 31a, 31b, 31c, etc. are suitably secured between the upper and lower wal:Ls 32 and 33 of the box, as s~own at FIG. 4. Each compartment is provided with a control valve 40 suitably interconnected with an air supply A and a steam supply S. The air supply is connected with an air feed line 43 and the steam supply is connected with a steam feed line 45. The valve means 40 include a hollow body 42 and a valve stem 41 which carries a double-truncated conical valve body 44 mating with respective valve seats 44a and 44b. Valve seat 44a is formed at the upper portion of valve body 42 while valve seat 44b is formed within the steam pipe 45. By selectively moving the valve stem 41 either the valve seat 44a can be shut while valve seat 44b can be opened, as shown in FIG. 5 or the steam may be moved upwardly to shut the steam supply pipe by blocking valve seat 44b while opening the air supply valve seat 44a. As best seen at FIG. 4, the compressed air source and steam sources are respectively connected to headers which interconnect with the respective valve means associated with each compartment. The valves are so positioned away from the front face 34 that a pressurized stream of air/steam cannot directly impinge on a surface adjacent the open face.
FIG. 6 shows an alternate embodi~ent of a control valve useful in the practice of the invertion. As shown, a ball valve 40a is provided for connecting the steam feed pipe 45 with the box 30 and with the air feed line 43. Movement of the valve stem 41a allows either steam or air to flow through the valve housing into the steam box 30.
Referring now to FIG. 7, a portion of a web W is shown travelinr, in the machine direction M and extending in a cross-machil direction CM of a paper-making machine~ A
~.223473 plurality of moisture sensors Sl, S2, S3, S4, e~c. are positioned in working relationship with the web W and the steam/air box 30, with each sensor associated with a select cross-machine area of the we~. ~ach sensor senses the moisture level in its given area of the web and generates a signal which is fed to an oper-ational computer. The computer is electrically connected to a plurality of solenoid-operated valves 40b, each associated with a given compartment of profiling box 30. In this manner, in accordance with the signal received from the sensors, the computer opens or closes valves 40b to admit steam or relatively dry air to the particular compartment.
Thus, it will be seen that we have provided an improved method and apparatus for more effective control of the cross-machine moisture profile of a paper web, particularly in conjunction with a press section of a paper-making machine which meets the objectives and advantages above set forth and accentuates moisture removal in wet areas of a web while retarding water xemoval in dry areas thereof.
BACKGROUND OF THE INVENTION
The invention relates to improved paper-making machines and somewhat more particularly to improved means for effective control of cross-machine moisture profile in a traveling paper web undergoing dewatering, as in a press section.
Prior Art Methods and mechanisms for applying steam to aid in dewatering a paper web are known, for example, see U. S. Patent No. 4,272,316 or U. S. Patent No. 4,163,688.
A presently accepted theory for this technique is that as a paper web or sheet is heated by applied steam, the viscos-ity of water insuch web is reduced, making water removal easier.
Recent developments in this area include compartmentalized steam boxes having separate cross-machine compar~ments allowing steam to be selectively applied in the cross-machine direction to a traveling web. Typically, such steam boxes are positioned about the outer surface of a suction roll so that steam can be drawn into th~ suction box and through the web supported by such roll.
The ability to correct or control the cross-machine moisture profile in a web has met with various degrees of success and problems still remain. One of such problems is that each com-partment cannot ~e readily sealed against the surface of the ~raveling web. One reason for this is that a minimum clea~nce of about 1" between the surface of the steam box and the suction ~ 223473 roll must be malntained in order to avoid damages from wads, wrap-ups, etc. With such large clearances, much of the applied steam in one compartment is frlee to migrate to adjacent compzrt-ments, with a resultant indiscriminate application of steam.
SUMMARY OF THE IN~ENTION
The invention provides a method and means which overcomes the prior art drawbacks and provides a more effective control of cross-machine moisture profile in a traveling paper web undergoing moisture removal in a paper-making machine.
In preferred embodiments of the invention, a compartmentalized system, such as in a chamber, is provided in working relation with a tra~eling paper web undergoing dewater-ing, as in a paper-making machine press section. This system includes a plurality of cross-machine profiling areas of compartments, each having valve-controlled means selectively supplying relatively dry air and/or steam to the web area associated with each profiling area.
In an exemplary embodiment of the inven~ion, a steam box having a plurality of cross-machine compartments is posi-tioned in close-running relation to a fluid-permeable means supporting a traveling web, typically a press nip defined by two press members, such as press rolls, one of which can be a grooved roll or a suction roll. The steam box is provided with a first cross-machine header, connected to a steam supply in the paper-making machine. Exiting from such header is a plur-ality of supply pipes and control valves, each associated with an individual compartment of the steam box. In addition, the steam bo~ is provided with a second cross-machine header~ con-nected to a compressed air source in a paper-making machine, ~ 2;~3473 with supply pipes and control valves associated therewith and with each individual compartment.
In preferred embodiments, a single valve means controls both the steam and air flow to an individual compartment. Each valve means can be interconnected to a computer and moisture sensors can be associated with select transverse areas of a traveling web and be interconnected to the computer so that the valves are appropriately activated by the computer for steam and/or air flow in accordance with the signal generated by the sensors.
In accordance with the principles of the invention, the air supply can be used to "flood" a compartment so as to prevent cross-machine migration of steam into that area.
Selectively supplying dry air to a select compartment of a steam box is further advantageous in that it can be utilized to con-trol dry areas of a sheet. As air is drawn into a sheet, evaporation cooling occurs, reducing the sheet temperature. At lower sheet temperatures, pressing is less effective. Hence, steam is supplied to control wet streaks in a sheet and air supply to control dry streaks in a sheet.
Other ob;ects, advantages and features as well as equivalent structures and methods which are intended to be covered herein will become more apparent with the teachings of the principles of the present invention in connection with the disclosure of the preferred embodiments thereof in the specification, claims and drawings, in which:
~1223473 BRIEF DESCR]:PTION OF THE DRAWINGS
FIG. 1 is a schemat:ic elevational p~rtial view illustrating a section of a paper-making machine constructed and operating in accordance ~ith the principles of the invention;
FIG. 2 is another somewhat similar schematic elevational view showing another form of the invention;
FIG. 3 is a partial somewhat schematic elevational view illustrating a steam/air box of the invention in association with a grooved press roll;
FIG. 4 is a partially broken-away top view illustra~ing one form of header arrangements utilized to supply air/steam to the airlsteam box of the invention;
FIG. 5 is an elevated detailed view cf a valve arrangement utilized to control steam/air in the air/steam box of the invention;
FIG. 6 is an elevated detailed view of an alternative valve arrangement utilized in the practice of the invention; and FIG. 7 is a schematic di.agram illustrating a working relation between a computer, moisture sensors and respective valve means of an air/steam box constructed and operable in accordance with the principles of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As illustrated in FIG. 1, a newly formed web W is carried on the upper surface of a traveling first endless felt, Fl, for example, from a Fourdrinier machine or from a first press section (not shown), into a psess nip Nl defined between ~.Z23473 a lower grooved roll 11 and an upper suction roll 12. A travel-ing second endless felt F2 is guided by guide rolls (not shown), so as to sandwich the web W between the felts Fl and F2 as they pass through the press nip Nl. At the press nip Nl, water is removed downwardly into the grooved roll G and from there to a saveall in a conventional manner. On the off-running side of the nip Nl, the web W adheres to the second felt F2 as this felt travels around the suction roll 12 in the manner shown. The first felt Fl is guided away fro~ the press nip Nl by a suitable guide roll and back through its endless loop in a conventional manner. The second ~elt F2, carrying the web W on its outer surface, travels around the suction roll 12 and past the suction gland 13 as illustrated. A profiling steam/air box 15 is posi-tioned in close working relation with the o~ter surface of the suction roll 12 so as to feed air or steam to select areas of the web via a controlled valve 15a connected to a steam source S
and to an air source A. The supplied steam and/or air streams penetrate through the felt F2 and into the web W and thence into the suction gland 13 of the suction roll 12 to effect tempera-ture control of the associated areas of the web. A plain-surfaced press roll 14 is positioned above suction roll 12 so as to define a second nip ~2. A third endless traveling felt F3 is guided over the surface of the plain press roll and against the web W so as to sandwich the web between the felts F2 and F3.
The so-sandwiched we.b is then carried away for further process-ing, for example, to another press section or to a dryer seetion of a paper-making machine.
FIG. 2 shows another press section wherein the profiling air/steam box of the invention is advan~ageously employed. In the embodiment here illustrated, a newly fo-rmed i223~73 web W is carried on a top surface of a first endless felt Fl into a first press nip Nl defirLed by an upper plain roll 23 and a lower grooved roll 22. Just prior to the press nip Nl, a compartmentalized profiling airlsteam box 21 is positioned in close running relation with the felt Fl so as to selectively feed steam and/or air upwardly through the felt Fl and into the web W via control valve 21a. At this location, steam aids water re~oval while dry air retards water removal so that steam can be supplied to control wet streaks in the newly formed web or sheet and air can be supplied to control the dry areas thereof.
After the press nip Nl, the felt Fl carries the web W into a second press nip N2 defined by a lower plain roll 24 and an upper suction roll 25 having a suction gland 25a. On the off-running side of the nip N2, the felt Fl is guided awa-; from the web W
back through its endless run via a plurality of guide rolls (not shown). The web W continues to adhere to the outer surface of the suction roll 25 because of the suction gland 25a. A
second profiling air/steam box 26 is positioned in close running relation with the outer surface of the suction roll in close conformity with the suction gland 25a and selectively feeds air or steam against the web surface via control valve 26a. Heated water is more readily withdrawn from the web via the suction gland whereas cooled water (cooled by supplied air) is somewhat more difficult to withdraw so that control of wet and/or dry streaks in the web W can be readily accomplished. A second endless traveling felt F2 is guided around a further plain press roll 27 positioned to define a further press nip N3 with the suction roll 25. On the off-running side of the nip N3, the felt F2 carries the web W on its undersurface away for further processing as desir~d, ~L2234~73 The profiling steamjair boxes of the invention, such as boxes 21 ~nd 26, correct cross-machine moisture profiles in webs undergoing dewatering. Each steam box is relatively fluid impermeable except for an open front face and is divided into a number of compartments in the cross-machine direction. Cross-machine headers are provided to supply compressed steam and air, respectively, to each compartment, which also includes an individual control valve. As is ~own, paper-making machines typically include a source of pressurized steam and may include a source of pressurized air. In any event, relatively dry air can be supplied from an external source by a fan or other suit-able means. A select air stream can be used to flood a compart-ment to prevent cross-machine migration of steam into the flooded compartment. Further, such dry air stream provides a means of controlling dry areas of a sheet since as air is drawn into a sheet, evaporation cooling occurs reducin~ the sheet temperature, making water removal less efficient. In this manner, dry areas can be controlled and by selectively applying steam to other areas, wet streaks can be controlled.
Referrin8 to FIG. 3, a grooved roll 35 having a plurality of grooves 35a is shown positioned in working relation wlth a profiling and/or steam box 30. The box 30 is provided with a back wall 31, an upper wall 32, a lower wall 33 and a forward open face 34, along with appropriate end walls (not shown), all joined to~ether in a relatively fluid-tight manner so as to be able to direct the steam and/or air flow toward the front face 34 of the bo~ 30. The walls are preferably formed from sheet mPtal and a plurality of individual compartments, for examp?e, a~out 6'l in width, are provided along the cross-machine di~ection of the box. For this purpose, a plurality of :iL223473 compartment walls 31a, 31b, 31c, etc. are suitably secured between the upper and lower wal:Ls 32 and 33 of the box, as s~own at FIG. 4. Each compartment is provided with a control valve 40 suitably interconnected with an air supply A and a steam supply S. The air supply is connected with an air feed line 43 and the steam supply is connected with a steam feed line 45. The valve means 40 include a hollow body 42 and a valve stem 41 which carries a double-truncated conical valve body 44 mating with respective valve seats 44a and 44b. Valve seat 44a is formed at the upper portion of valve body 42 while valve seat 44b is formed within the steam pipe 45. By selectively moving the valve stem 41 either the valve seat 44a can be shut while valve seat 44b can be opened, as shown in FIG. 5 or the steam may be moved upwardly to shut the steam supply pipe by blocking valve seat 44b while opening the air supply valve seat 44a. As best seen at FIG. 4, the compressed air source and steam sources are respectively connected to headers which interconnect with the respective valve means associated with each compartment. The valves are so positioned away from the front face 34 that a pressurized stream of air/steam cannot directly impinge on a surface adjacent the open face.
FIG. 6 shows an alternate embodi~ent of a control valve useful in the practice of the invertion. As shown, a ball valve 40a is provided for connecting the steam feed pipe 45 with the box 30 and with the air feed line 43. Movement of the valve stem 41a allows either steam or air to flow through the valve housing into the steam box 30.
Referring now to FIG. 7, a portion of a web W is shown travelinr, in the machine direction M and extending in a cross-machil direction CM of a paper-making machine~ A
~.223473 plurality of moisture sensors Sl, S2, S3, S4, e~c. are positioned in working relationship with the web W and the steam/air box 30, with each sensor associated with a select cross-machine area of the we~. ~ach sensor senses the moisture level in its given area of the web and generates a signal which is fed to an oper-ational computer. The computer is electrically connected to a plurality of solenoid-operated valves 40b, each associated with a given compartment of profiling box 30. In this manner, in accordance with the signal received from the sensors, the computer opens or closes valves 40b to admit steam or relatively dry air to the particular compartment.
Thus, it will be seen that we have provided an improved method and apparatus for more effective control of the cross-machine moisture profile of a paper web, particularly in conjunction with a press section of a paper-making machine which meets the objectives and advantages above set forth and accentuates moisture removal in wet areas of a web while retarding water xemoval in dry areas thereof.
Claims (12)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An apparatus for effective control of cross-machine moisture profile of a paper web in a paper-making machine, in combination:
fluid-permeable means supporting a traveling paper web undergoing dewatering;
a compartmentalized steam/air box positioned in working relation with said fluid-permeable means, said box extending in a cross-machine direction substantially across the width of said paper web and having an open front face in fluid communication with said fluid-permeable means and being positioned in relatively close proximity thereto, said box having a plurality of separated compartments each in fluid communication with said front face and each having a controllable steam and air outlet located away from said front face so as to allow a stream of steam or air to flood each respective compartment and permeate a corresponding area of said fluid-permeable means;
a source of compressed steam and a source of compressed air in fluid communication with said controllable steam and air outlets of each compartment; and a water-removal means positioned in working relation with said steam/air box for removing water from said paper web.
fluid-permeable means supporting a traveling paper web undergoing dewatering;
a compartmentalized steam/air box positioned in working relation with said fluid-permeable means, said box extending in a cross-machine direction substantially across the width of said paper web and having an open front face in fluid communication with said fluid-permeable means and being positioned in relatively close proximity thereto, said box having a plurality of separated compartments each in fluid communication with said front face and each having a controllable steam and air outlet located away from said front face so as to allow a stream of steam or air to flood each respective compartment and permeate a corresponding area of said fluid-permeable means;
a source of compressed steam and a source of compressed air in fluid communication with said controllable steam and air outlets of each compartment; and a water-removal means positioned in working relation with said steam/air box for removing water from said paper web.
2. An apparatus for effective control of cross-machine moisture profile of a paper web in a paper-making machine as defined in claim 1 wherein said fluid-permeable means consists of a traveling endless felt.
3, An apparatus for effective control of cross-machine moisture profile of a paper web in a paper-making machine as defined in claim 1 wherein said fluid-permeable means consists of an outer surface of a suction roll gland.
4. An apparatus for effective control of cross-machine moisture profile of a paper web in a paper-making machine as defined in claim 1 wherein said fluid-permeable means consists of a press nip formed between a first press member and a second press member defining a pressing zone therebetween through which said paper web is carried subject to a dewatering pressure.
5. An apparatus for effective control of cross-machine moisture profile of a paper web in a paper-making machine as defined in claim 4 wherein said first press member is a plain-surfaced press roll and said second press member is a grooved press roll.
6. An apparatus for effective control of cross-machine moisture profile of a paper web in a paper-making machine as defined in claim 4 wherein said first press member is a suction press roll and said second press member is a plain-surfaced roll.
7. An apparatus for effective control of cross-machine moisture profile of a paper web in a paper-making machine as defined in claim 1 wherein said fluid-permeable means consists of a pair of press nips formed between a lower plain-surfaced press roll, an intermediate suction press roll and an upper plain-surfaced roll, each of said plain-surfaced press rolls defining an individual pressing zone with said suction press roll through which said paper web is successively carried subjected to a de-watering pressure, and said compartmentalized steam/air box is positioned in working relation with the suction gland of said suction roll between the respective press nips formed by the respective plain-surfaced press rolls and said suction press roll.
8. An apparatus for effective control of cross-machine moisture profile of a paper web in a paper-making machine as defined in claim 1 wherein said compartmentalized steam/air box compartments each are provided with a single valve means controlling flow of steam and air into each such compartment.
9. An apparatus for effective control of cross-machine moisture profile of a paper web in a paper-making machine as defined in claim 8 wherein said valve means include a hollow valve housing having an upper wall, a lower wall and side walls joined in a relatively fluid-tight manner, said air outlet being in fluid communication with said hollow valve body, a movable valve stem threadingly supported along the bottom wall of said valve housing and carrying a double-truncated conical valve body at an outer end thereof, a first valve seat formed in an upper wall of said valve body and mating with a first end of said valve body, said first valve seat being in fluid communication with the associated compartment, and a second valve seat spaced from said first valve seat and formed in an outer wall of said steam outlet and mating with a second end of said valve body whereby pressur-ized steam from said steam outlet is directed through said second valve seat against said second end of said valve body and pressur-ized air is directed through said first valve seat against said first end of said valve body so as to permeate the compartment associated with such valve means, with steam or air in accordance with the position of said valve body.
10. An apparatus for effective control of cross-machine moisture profile of a paper web in a paper-making machine as defined in claim 8 wherein said valve means comprises a ball valve in selective fluid communication with said steam and air sources and with a given compartment of said steam/air box and includes an actuating means for selective providing communication between said steam or air source and said compartment.
11. An apparatus for effective control of cross-machine moisture profile of a paper web in a paper-making machine as defined in claim 8 wherein said valve means comprises a solenoid valve and a plurality of moisture sensors are provided in working relation with select cross-machine areas of said paper web corre-sponding to a compartment of said steam/air box, a computer being connected with said moisture sensors and with each of said solenoid valves so that during operation, said moisture sensors feed a signal to said computer in accordance with the moisture level in a paper web area being monitored by such sensor and said computer opens or closes the flow of steam or air into each compartment in accordance with said signal.
12. A method of effectively controlling cross-machine moisture profile of a paper web in a paper-making machine, comprising, in combination, the steps of:
selectively feeding a stream of steam or relatively dry air to select cross-machine areas of a paper web undergoing dewatering in a paper-making machine; and removing water from such paper web.
selectively feeding a stream of steam or relatively dry air to select cross-machine areas of a paper web undergoing dewatering in a paper-making machine; and removing water from such paper web.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US42856582A | 1982-09-30 | 1982-09-30 | |
| US428,565 | 1982-09-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1223473A true CA1223473A (en) | 1987-06-30 |
Family
ID=23699456
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000436842A Expired CA1223473A (en) | 1982-09-30 | 1983-09-16 | Profiling air/steam system for paper-making machines |
Country Status (10)
| Country | Link |
|---|---|
| JP (1) | JPS6037236B2 (en) |
| KR (1) | KR860001606B1 (en) |
| CA (1) | CA1223473A (en) |
| ES (1) | ES8502502A1 (en) |
| GB (1) | GB2127871B (en) |
| ID (1) | ID1006B (en) |
| IN (1) | IN162681B (en) |
| IT (1) | IT1167389B (en) |
| MX (1) | MX157930A (en) |
| PH (1) | PH25720A (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3675221D1 (en) * | 1986-02-04 | 1990-11-29 | Beloit Corp | CONTROL VALVE FOR STEAM BOX. |
| GB2189270B (en) * | 1986-04-16 | 1989-07-12 | Nash Engineering Co | Method of partially deliquifying moisture-containing paper web. |
| US4928013A (en) * | 1987-02-17 | 1990-05-22 | Measurex Corporation | Temperature insensitive moisture sensor |
| US5240564A (en) * | 1989-06-06 | 1993-08-31 | Valmet Paper Machinery Inc. | Method for the control of the nip-pressure profile in a paper making machine |
| IT1232534B (en) * | 1989-06-30 | 1992-02-19 | Bosso Carte Speciali Spa | HUMIDIFIER DEVICE FOR A TAPE OF SHEET MATERIAL, IN PARTICULAR PAPER |
| US5338361A (en) * | 1991-11-04 | 1994-08-16 | Measurex Corporation | Multiple coat measurement and control apparatus and method |
| US5276327A (en) * | 1991-12-09 | 1994-01-04 | Measurex Corporation | Sensor and method for mesaurement of select components of a material |
| DE19534573C2 (en) * | 1995-09-18 | 2001-08-23 | Voith Sulzer Papiermasch Gmbh | Steam blower box and method for zone-wise tempering of a running paper web |
| DE19829131A1 (en) * | 1998-06-30 | 2000-01-13 | Wilhelm Wanke | Process for smoothing fibrous webs, preferably paper or cardboard webs, including exposure to medium, and devices therefor |
| US6964117B2 (en) * | 2002-12-20 | 2005-11-15 | Metso Paper Usa, Inc. | Method and apparatus for adjusting a moisture profile in a web |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB844386A (en) * | 1956-01-26 | 1960-08-10 | Lippke Paul | Improvements in or relating to the controlling of the moisture content of a travelling web of paper, pulp or board |
| US3097994A (en) * | 1961-02-03 | 1963-07-16 | Kimberly Clark Co | Steaming device for a papermaking machine |
| GB1589072A (en) * | 1977-04-05 | 1981-05-07 | Greenbank Cast Basalt Eng Co | Drying apparatus for paper making machines and other cylinder drying machines |
| SE7910025L (en) * | 1978-12-21 | 1980-06-22 | Midland Ross Corp | KIT AND DEVICE FOR DRYLY DRYING A CONTINUOUS CONTINUOUS MATERIAL MATCH OF CELLULOSA FIBER |
-
1983
- 1983-08-24 PH PH29441A patent/PH25720A/en unknown
- 1983-09-08 ID IDP393183A patent/ID1006B/en unknown
- 1983-09-13 IN IN1121/CAL/83A patent/IN162681B/en unknown
- 1983-09-13 JP JP58167647A patent/JPS6037236B2/en not_active Expired
- 1983-09-16 CA CA000436842A patent/CA1223473A/en not_active Expired
- 1983-09-27 ES ES525986A patent/ES8502502A1/en not_active Expired
- 1983-09-28 GB GB08325915A patent/GB2127871B/en not_active Expired
- 1983-09-29 MX MX198908A patent/MX157930A/en unknown
- 1983-09-30 KR KR1019830004676A patent/KR860001606B1/en not_active IP Right Cessation
- 1983-09-30 IT IT23089/83A patent/IT1167389B/en active
Also Published As
| Publication number | Publication date |
|---|---|
| ES525986A0 (en) | 1985-01-01 |
| KR840005850A (en) | 1984-11-19 |
| KR860001606B1 (en) | 1986-10-13 |
| GB2127871A (en) | 1984-04-18 |
| IT1167389B (en) | 1987-05-13 |
| GB8325915D0 (en) | 1983-11-02 |
| ID1006B (en) | 1996-10-14 |
| JPS6037236B2 (en) | 1985-08-24 |
| IT8323089A1 (en) | 1985-03-30 |
| ES8502502A1 (en) | 1985-01-01 |
| PH25720A (en) | 1991-09-18 |
| JPS5966595A (en) | 1984-04-16 |
| MX157930A (en) | 1988-12-21 |
| IN162681B (en) | 1988-07-02 |
| IT8323089A0 (en) | 1983-09-30 |
| GB2127871B (en) | 1986-06-11 |
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