WO1991013205A1 - Steam shower and vacuum apparatus and method of using same - Google Patents
Steam shower and vacuum apparatus and method of using same Download PDFInfo
- Publication number
- WO1991013205A1 WO1991013205A1 PCT/US1991/001167 US9101167W WO9113205A1 WO 1991013205 A1 WO1991013205 A1 WO 1991013205A1 US 9101167 W US9101167 W US 9101167W WO 9113205 A1 WO9113205 A1 WO 9113205A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- steam
- web
- vacuum
- sheet
- shower
- Prior art date
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B13/00—Machines and apparatus for drying fabrics, fibres, yarns, or other materials in long lengths, with progressive movement
- F26B13/10—Arrangements for feeding, heating or supporting materials; Controlling movement, tension or position of materials
-
- 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
- D21F7/00—Other details of machines for making continuous webs of paper
- D21F7/008—Steam showers
Definitions
- This invention relates to papermaking and more particularly to an apparatus and a method for controlling the temperature of a web or sheet of paper as it enters the press section through the utilization of a stepping motor to open and close valve pipes in order to control the application of steam against the sheet surface and the corresponding withdrawal of the steam by a suction device through the opposite side of the sheet that contacts the forming fabric (wire) .
- the vacuum source can also serve to draw the steam into the web and increase steam penetration. This increased steam penetration serves to increase the operating efficiency of the steam shower and the heat transfer to the web.
- This vacuum source is typically run at a constant uniform vacuum level in the transverse or cross direction (CD) without any -regulation of volume once the machine has stabilized.
- the press section of a paper making machine is located before the dryer section. Therefore, increasing the water removal rate through the press section serves to decrease the moisture content of a sheet entering the dryer section, thereby either reducing the energy consumption required to further dry the sheet or increasing production (speed) at constant dryer section energy consumption.
- consumed steam should be maximized for its effective use.
- the percentage of consumed steam that condenses on and in the sheet for the purpose of raising the sheet temperature should be maximized, and the percentage of consumed steam that does not condense but instead exhausts to the atmosphere as wasted energy should be minimized.
- a steam shower apparatus for use in controlling the temperature of a sheet by applying steam against the upper surface of the sheet.
- a corresponding vacuum zone Directly beneath this steam application zone is a corresponding vacuum zone.
- the vacuum zone's purpose is to enhance profilability and increase the response of the steam shower itself.
- the vacuum zone acts as the bottom half of a steam-web-vacuum sandwich.
- the controlled application of steam across the machine at equally spaced increments can be employed to control the initial and hence final moisture profile of the sheet.
- the controlled removal of moisture/steam at such equally spaced increments is accomplished by the use of a measurement computer system which controls a stepping motor.
- the stepping motor in turn controls the appropriate valves in both the vacuum and steam zones in order to send a certain amount of both vacuum and steam to the web.
- This process varies the amount of steam application and vacuum volume directly beneath the steam application zone. This can be accomplished because directly beneath the steam application zone is a vacuum steam removal zone of similar dimensions. When the output of steam is increased through the steam box the vacuum beneath this individual zone is increased.
- This combination of steam application and steam removal serves to enhance the effectiveness of the process as well as enable the operator's to have better control of the web's profile.
- the marrying of the steam application to the vacuum source insures that the steam goes where it is intended.
- the vacuum could be increased without changing the steam rate to increase water removal.
- the principal object of the apparatus is to make maximum usage of generated steam and efficiently utilize the energy required for generating steam when applying steam to a paper web.
- a further object of the present invention is to provide a steam shower apparatus for a paper making machine which applies steam in such a way that the entrainment of non-condensable air into the condensation space, which severely hampers condensation heat transfer, is limited or eliminated.
- Another object of the present invention is to provide a steam shower apparatus for a paper making machine that allows for improved accuracy and repeatability of steam flow control, vacuum flow and level control.
- Still another object of the present invention is to provide a steam shower apparatus for a paper making machine that applies steam to a sheet in such a way that uniformity of heat-transfer is provided in the cross-machine direction (non-uniformity is necessary for profile correction) .
- Yet another object of the present invention is to eliminate the moisture condensation on the outermost surfaces of the apparatus to prevent dripping on the sheet traveling through the apparatus.
- FIG. 1 is a schematic view of a portion of a paper making machine including the steam shower/vacuum apparatus of the present invention.
- Fig. 2 is a sectional view of a steam shower/vacuum apparatus of the present invention, positioned adjacent to the sheet, employing positional steam flow control and positional vacuum flow control.
- FIG. 3 is a sectional view of a further alternate embodiment of the steam shower/vacuum apparatus shown in FIG 1 in which the bottom surface of the apparatus is heated by a resistance electrical heater.
- FIG. 4 is a sectional view of a further alternate embodiment of the steam shower/vacuum shown in FIG. 1 in which the steam supply manifold forms the bottom portion of the apparatus.
- FIG. 5 is a sectional view of an additional embodiment of the steam shower/vacuum apparatus shown in FIG. 5.
- FIG. 6 is a simplified plan view of another embodiment of the steam shower/vacuum apparatus shown in FIG. 6 with only the steam supply manifold of the apparatus being shown.
- FIG. 7 is a sectional view of a stepper motor with valve body positioned within both the steam and vacuum zones.
- FIG. 8 is a schematic view of the computer control system which controls the amount of both steam and vacuum applied to the web.
- FIG 9 is a schematic view of the logic control panel shown in FIG 8.
- the present invention is a steam profiling apparatus which includes steam showers 10, positioned at strategic locations on the paper making machine, with a device for creating a vacuum 21, positioned directly beneath the steam shower.
- a steam shower vacuum combination is positioned on the forming section of a paper making machine with one or more additional steam shower vacuum couples positioned so that the web flows between them after it leaves the forming section of the paper making machine and before it enters the press section.
- the steam shower extends across the entire width of the paper making machine producing a line of steam in the cross machine direction.
- the vacuum positioned directly beneath the steam shower also has a vacuum chamber which extends beneath the steam shower so as to produce a zone of lower pressure directly beneath the zone where the steam is being applied to the web.
- the steam apparatus 10 includes a steam supply manifold 12 which applies steam through a feed pipe 14 to a chamber 16 leading to a combination Coanda nozzle 18 and impingement nozzle 20.
- the vacuum apparatus 21 includes a vacuum supply manifold 22 which through a feed-pipe 24 reduces the pressure in a chamber 26 that is positioned parallel to and directly beneath the steam zone discussed above.
- the Coanda nozzle 18 is arranged in the apparatus so that the steam flowing through the Coanda nozzle 18 is directed along a surface of the apparatus 10 which is positioned adjacent and parallel to the sheet 28 which is to be heated.
- the steam flows in a direction opposite to the direction of travel of the sheet.
- the direction of travel of the sheet is shown by arrow 30.
- This Coanda nozzle 18 The main purpose of this Coanda nozzle 18 is to remove the boundary layer of entrained air traveling with the sheet 28. This layer of air normally acts as an insulator preventing the steam from penetrating the sheet 28. Additionally, a corresponding vacuum chamber 26 is located opposite the steam nozzle 18 and 20 to maximize the amount of steam drawn into the web and subsequently increase profilability.
- a preferred embodiment of the present invention includes means for heating the outside bottom surface of the apparatus to prevent discharge steam condensing thereupon and dripping moisture on the sheet.
- the outside bottom surface could be heated electrically, for example with an electrical resistance heater.
- the steam supply manifold is located in the lower portion of the apparatus so that the bottom wall of the apparatus is also the bottom wall of the steam supply manifold.
- the apparatus is mounted above the traveling sheet so that a downstream corner of the apparatus contacts the web so that steam is back pressured between the sheet and the apparatus.
- the key to this invention is the marriage of the two devices (steam shower and vacuum chamber) with both the steam and coordinate control system.
- the control system will adjust the vacuum section beneath the steam section as appropriate. Quite simply this system will recognize when it is necessary for it to increase or decrease steam and/or vacuum flow and react accordingly.
- those methods available are limited to profilable steam boxes and non-profilable vacuum boxes.
- the present invention is a new device (i.e. profilable vacuum system coupled to a profilable steam system) that requires the sophistication of a combined control system to operate effectively. This is shown in FIGS 8 and 9. This is done by the use of a measurement computer system 40.
- the measurement computer system 40 measures the quality of the paper which is affected by the steam shower and vacuum apparatus.
- the measurement computer system 40 then electrically sends a signal to the operators console 42.
- the operators console 42 interprets the signal and sends a signal to the logic control panel 44.
- the logic control panel 44 receives the computer's signal and outputs instructions 52 for the stepper motor chamber to control the appropriate valves in both the vacuum zone and the steam zone 54 which will adjust the inlet orifices in both the vacuum and steam zone, and ultimately send a certain amount of both vacuum and steam to the web.
- the logic control panel' 44 controls aspects of the steam by analyzing the pressure 46 and temperature 50 of such steam and sending a signal 48 to the steam supply before the steam enters the apparatus.
- the vacuum section serves to enhance the effectiveness of the steam shower by increasing the percentage of steam brought into the sheet at the appropriate location and limiting the migration of steam to adjacent locations.
- a conventional profiling steam shower is to correct moisture inconsistencies in the web.
- the steam shower does this by applying steam to those sections that have more moisture than desired, effectively preheating those particular sections of the web. As the web is passed through the dryer the excess moisture which has been preheated will evaporate sooner, thus actually reducing the moisture level in that section.
- the steam shower apparatus for supplying steam to a web or sheet includes an air-foil type nozzle, utilizing the Coanda effect, to impart steam in a direction roughly parallel but opposite in direction to the direction of travel of the sheet.
- This Coanda effect steam foil* blocks the boundary layer of entrained air traveling with the sheet and subsequently serves to increase efficiency.
- the counter parallel-flow nature of the system insures that the exhausting steam creates a positive pressure "wall" at the incoming or downstream edge of the apparatus, thereby decreasing the volume of air which can be entrained by the moving sheet.
- the velocity of the sheet serves to limit the volume of air entering the condensing space, close to the surface of the exiting sheet.
- An additional feature of the invention is that the high velocity counter-flow running parallel to the sheet insures that even after exhausting at the upstream edge, a significant percentage of the non-condensed steam continues to flow roughly parallel to the sheet for a considerable distance, effectively preheating the sheet before it actually enters the apparatus. This non-condensed steam thereby serves to effectively utilize some of the exhaust steam which would otherwise be wasted.
- the steam shower utilizes a unique hole pattern to impart steam into the web via impingement, thereby insuring uniformity of steam flow and heat transfer in the cross-machine direction at the desired positional location.
- the Coanda nozzle blocks the boundary layer of entrained air and preheats the web while the impingement nozzle applies pressurized steam into the web. This combination of the two application techniques maximize the efficiency of the steam shower itself.
- Both steam and vacuum are supplied to the apparatus and conveyed across the machine width by an oversized distribution header (typically having a ten inch diameter) to insure uniform supply distribution across the machine, feed-pipes (typically having a two inch diameter) located normal to the axis of the supply manifold traverse the diameter of the supply manifold.
- an oversized distribution header typically having a ten inch diameter
- feed-pipes typically having a two inch diameter
- the impingement chamber 16, shown in Fig. 1, and corresponding nozzle are divided into several chambers and associated nozzles by positioning baffles around several feed pipes.
- Each of the these feed pipes is connected to a direct-current stepper motor.
- a direct-current stepping motor 110 is mounted on the outboard end of the feed-pipe 112.
- a valve pipe 124 is located within the feed-pipe 112.
- a lead-screw type coupling 114 connects the stepping motor shaft 116 to a valve stem 118 which connects to the translating valve-poppet 120 located in the body of the feed-pipe in the region of the inlet orifice 122.
- stepper motor shaft 116 changes its position, it turns the coupling 114, which causes the valve stem 118 to move longitudinally toward the valve poppet 120.
- the valve poppet 120 is moved to open or close the orifice 122 in the valve pipe 124. This is done to either totally close the orifice 122 to prevent steam in the steam zone, and vacuum in the vacuum zone from entering the valve pipe 124 at the inlet orifice 122, or to partially close the orifice 122 to thereby adjust the volume of steam and vacuum entering the valve-pipe 124.
- Positioning of the stepper motor shaft angle translates the valve poppet 120 so as to increase or decrease the available open-area of the feed-pipe inlet orifice.
- the flow-rate of steam through the feed-pipe inlet orifice may be controlled, thereby enabling the controlled application of steam to the sheet.
- the choice of a stepping- otor 110 as the preferred type of valve actuator is particularly important to the accuracy and repeatability of the control process.
- the small angular increments of shaft position 116 typically 2 degrees per step
- the turn-down ratio of the lead-screw coupling 114 combine to provide approximately 5000 precise and repeatable available valve-poppet 120 positions over a total valve-poppet travel of one inch.
- the specific values cited above may be changed in accordance with specific design requirements, but this example serves to indicate the extraordinary control definition, accuracy and repeatability available with such an actuator.
- an attractive aspect of the stepping-motor actuator is that it may be electrically coupled through actuator lines, directly to a computer control system, as seen in Figures 8 and 9.
- Such coupling eliminates the need for any intermediate signal conversion (i.e. from electric to pneumatic) , with an attendant presumed improvement in both control, accuracy and repeatabi1ity.
- the stepping-motor actuator may be replaced by any type of actuator which will operate a poppet-like device to provide the desired steam flow control.
- the main body of the apparatus is insulated about the supply-manifold with suitable insulation to minimize the likelihood of condensation carry-over and to maximize the usage of the steam latent heat for the purpose intended.
- the apparatus includes two separate structural chambers, the manifold/nozzle chamber 16 (which in the preferred embodiment is of fixed standardized length) and the control chamber 12 (which in the preferred embodiment is of variable length) .
- the variable length may be chosen so as to provide the apparatus length required to aid in the attainment of the necessary steam condensing rate for each specific application.
- both lengths may be chosen as fixed values, so as to provide a fixed apparatus length deemed to be satisfactory for the attainment of successful performance over the full range of expected applications.
- the bottom surface of the apparatus can be heated electrically, by means conventional to the art.
- the bottom surface can be heated with a resistance electrical heater, as shown in FIG. 3.
- modifications can be made in the structure of the apparatus to achieve the requisite goals.
- the embodiment of the steam shower apparatus shown in FIG. 4 also eliminates this condensation.
- the steam supply manifold is-configured so that the steam supply manifold constitutes the entire bottom surface of the apparatus. Steam within the steam supply header is either at a sufficient pressure (approximately 5-15 psig) or at a sufficient superheat temperature to insure that the temperature of the outside bottom surface 146 is above 180 degrees Fahrenheit.
- the "steam shower" apparatus could be constructed of a reduced cross-machine length, in any of the embodiments, to provide an apparatus whose function is to operate over only a reduced percentage of the actual paper-machine width.
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FI923890A FI923890A (en) | 1990-03-02 | 1992-08-31 | AONGSTRAOLE- OCH VAKUUMANORDNING SAMT FOERFARANDE FOER ANVAENDNING AV DENSAMMA |
NO92923414A NO923414L (en) | 1990-03-02 | 1992-09-01 | STEAM SHOWER VACUUM DEVICE AND PROCEDURE FOR USING THE SAME |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US48777290A | 1990-03-02 | 1990-03-02 | |
US487,772 | 1990-03-02 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1991013205A1 true WO1991013205A1 (en) | 1991-09-05 |
Family
ID=23937060
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1991/001167 WO1991013205A1 (en) | 1990-03-02 | 1991-02-22 | Steam shower and vacuum apparatus and method of using same |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0517821A4 (en) |
AU (1) | AU7493591A (en) |
CA (1) | CA2075993A1 (en) |
FI (1) | FI923890A (en) |
WO (1) | WO1991013205A1 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4322565A1 (en) * | 1993-07-07 | 1993-12-09 | Voith Gmbh J M | Paper-making blanket maintenance - uses combination of steam blower and suction on the same side of moving blanket |
US5588223A (en) * | 1994-06-14 | 1996-12-31 | Asea Brown Boveri Inc. | Restrained paper dryer |
WO2000079049A1 (en) * | 1999-06-17 | 2000-12-28 | Metso Paper, Inc. | A method for leading a web between calender nips, and a calender |
US20150218755A1 (en) * | 2014-02-04 | 2015-08-06 | Lucjan Edmund Raubic | Method and apparatus for improving efficiency of Uhle Boxes in the process of paper production by applying a homogeneous mixture of superheated humid air |
EP3408445A4 (en) * | 2016-01-28 | 2019-09-25 | Kimberly-Clark Worldwide, Inc. | Fibrous web dewatering apparatus and method |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3945881A (en) * | 1974-09-11 | 1976-03-23 | Lodding Engineering Corporation | Fourdrinier steam shower |
US4580355A (en) * | 1984-05-23 | 1986-04-08 | Measurex Corporation | System for distributing hot gas on a paper web |
US4662398A (en) * | 1986-02-04 | 1987-05-05 | Beloit Corporation | Control valve for a steam box |
GB2189270A (en) * | 1986-04-16 | 1987-10-21 | Nash Engineering Co | Press section of papermaking machine |
US4765067A (en) * | 1986-02-28 | 1988-08-23 | Thermo Electron - Web Systems, Inc. | Steam-shower apparatus and method of using same |
-
1991
- 1991-02-22 WO PCT/US1991/001167 patent/WO1991013205A1/en not_active Application Discontinuation
- 1991-02-22 EP EP19910905986 patent/EP0517821A4/en not_active Withdrawn
- 1991-02-22 AU AU74935/91A patent/AU7493591A/en not_active Abandoned
- 1991-02-22 CA CA 2075993 patent/CA2075993A1/en not_active Abandoned
-
1992
- 1992-08-31 FI FI923890A patent/FI923890A/en not_active Application Discontinuation
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3945881A (en) * | 1974-09-11 | 1976-03-23 | Lodding Engineering Corporation | Fourdrinier steam shower |
US4580355A (en) * | 1984-05-23 | 1986-04-08 | Measurex Corporation | System for distributing hot gas on a paper web |
US4662398A (en) * | 1986-02-04 | 1987-05-05 | Beloit Corporation | Control valve for a steam box |
US4765067A (en) * | 1986-02-28 | 1988-08-23 | Thermo Electron - Web Systems, Inc. | Steam-shower apparatus and method of using same |
GB2189270A (en) * | 1986-04-16 | 1987-10-21 | Nash Engineering Co | Press section of papermaking machine |
Non-Patent Citations (1)
Title |
---|
See also references of EP0517821A4 * |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4322565A1 (en) * | 1993-07-07 | 1993-12-09 | Voith Gmbh J M | Paper-making blanket maintenance - uses combination of steam blower and suction on the same side of moving blanket |
US5588223A (en) * | 1994-06-14 | 1996-12-31 | Asea Brown Boveri Inc. | Restrained paper dryer |
WO2000079049A1 (en) * | 1999-06-17 | 2000-12-28 | Metso Paper, Inc. | A method for leading a web between calender nips, and a calender |
US20150218755A1 (en) * | 2014-02-04 | 2015-08-06 | Lucjan Edmund Raubic | Method and apparatus for improving efficiency of Uhle Boxes in the process of paper production by applying a homogeneous mixture of superheated humid air |
EP3408445A4 (en) * | 2016-01-28 | 2019-09-25 | Kimberly-Clark Worldwide, Inc. | Fibrous web dewatering apparatus and method |
Also Published As
Publication number | Publication date |
---|---|
FI923890A0 (en) | 1992-08-31 |
FI923890A (en) | 1992-08-31 |
EP0517821A4 (en) | 1993-03-17 |
AU7493591A (en) | 1991-09-18 |
CA2075993A1 (en) | 1991-09-03 |
EP0517821A1 (en) | 1992-12-16 |
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