EP2757193A1 - Buse de pulvérisation et procédé de pulvérisation de fluides dans des gouttelettes pour traiter des bandes fibreuses - Google Patents

Buse de pulvérisation et procédé de pulvérisation de fluides dans des gouttelettes pour traiter des bandes fibreuses Download PDF

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Publication number
EP2757193A1
EP2757193A1 EP13152188.2A EP13152188A EP2757193A1 EP 2757193 A1 EP2757193 A1 EP 2757193A1 EP 13152188 A EP13152188 A EP 13152188A EP 2757193 A1 EP2757193 A1 EP 2757193A1
Authority
EP
European Patent Office
Prior art keywords
channel
nozzle
fluid
spray nozzle
range
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.)
Withdrawn
Application number
EP13152188.2A
Other languages
German (de)
English (en)
Inventor
Topi Tynkkynen
Tapio Pitkäniemi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Valmet Technologies Oy
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Valmet Technologies Oy
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Valmet Technologies Oy filed Critical Valmet Technologies Oy
Priority to EP13152188.2A priority Critical patent/EP2757193A1/fr
Publication of EP2757193A1 publication Critical patent/EP2757193A1/fr
Withdrawn legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
    • B05B7/02—Spray pistols; Apparatus for discharge
    • B05B7/06—Spray pistols; Apparatus for discharge with at least one outlet orifice surrounding another approximately in the same plane
    • B05B7/062—Spray pistols; Apparatus for discharge with at least one outlet orifice surrounding another approximately in the same plane with only one liquid outlet and at least one gas outlet
    • B05B7/066—Spray pistols; Apparatus for discharge with at least one outlet orifice surrounding another approximately in the same plane with only one liquid outlet and at least one gas outlet with an inner liquid outlet surrounded by at least one annular gas outlet
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
    • B05B7/02—Spray pistols; Apparatus for discharge
    • B05B7/10—Spray pistols; Apparatus for discharge producing a swirling discharge
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
    • D21G7/00—Damping devices
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
    • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
    • D21H23/22—Addition to the formed paper
    • D21H23/50—Spraying or projecting

Definitions

  • the present invention relates to a nozzle for spraying fluids in droplets for processing fibrous webs, wherein the nozzle comprises a housing having a first longitudinal central channel for the fluid to be sprayed and a second coaxially extending outer channel for a dispersing fluid, wherein the velocity vector of the fluid to be sprayed exiting from the opening of the first channel has mainly a linear component, that is the fluid exiting from the nozzle has essentially rectilinear motion, whereas the velocity vector of the dispersing fluid exiting from the opening of the second channel has both rotational and linear components, that is the dispersing fluid exiting from the nozzle has spiral motion.
  • processing fibrous webs covers coating or sizing papers and paper boards with coating or sizing agents, respectively, adding fiber suspensions, e.g. nanocellulose, to the paper or paper board webs, as well as other spraying processes for making paper or paper boards, e.g. for moistening webs with water or water including PVOH, starch or similar.
  • US 7820011 discloses a moistening nozzle for spraying water as mist to moisten a paper web.
  • the moistening nozzle comprises a frame to which air and water are fed, a water nozzle which is arranged inside the frame and wherewith water is conducted to an outlet of the moistening nozzle and an air nozzle wherewith air is conducted to an outlet of the moistening nozzle.
  • the air nozzle has an internal thread that brings the air into swirling motion, the internal threads being formed on the inner surface of the air nozzle.
  • US 6969012 relates to an atomizer comprising a housing having three inlets, three channels each including a nozzle in communication respectively with said inlets.
  • Said three inlets comprise a fluid-receiving first inlet, a fluid-receiving second inlet, a liquid-receiving third inlet, one of said channels being an inner channel.
  • Said inner channel is associated with said third inlet and is uniform in diameter. The one of said nozzles associated with said inner channel extends outwardly of said housing beyond the other two of said nozzles.
  • An angular swirling member is coaxially disposed in said housing with respect to said second nozzle.
  • a problem with these prior art nozzles is that the swirling motion is achieved by using internal threads in a chamber in which the dispersing fluid is fed axially.
  • These solutions have been useful as such, but there is still a need for more efficient dispersing of the fluid to be sprayed. It could be achieved by increasing the velocity of the dispersing fluid. With these prior art devices, this would require a higher fluid feed pressure with effective - and costly - compressors, and the higher velocity would mean higher linear and rotational components of the velocity vector of the dispersing fluid. With a higher linear velocity component the spray cone would be narrower and this is not desirable.
  • An aim of the present invention is to provide an improved spray nozzle which produces an improved rotational to linear component rate of the dispersing fluid by using low pressure blowers.
  • Another aim is to provide an improved method for spraying fluids in droplets for processing fibrous webs.
  • the nozzle comprises a housing having a first longitudinal central channel for the fluid to be sprayed and a second coaxially extending outer channel for a dispersing fluid, wherein the velocity vector of the fluid to be sprayed exiting from the opening of the first channel has mainly a linear component, that is the fluid exiting from the nozzle has essentially rectilinear motion, whereas the velocity vector of the dispersing fluid exiting from the opening of the second channel has both rotational and linear components, that is the dispersing fluid exiting from the nozzle has spiral motion, characterized in that the nozzle is provided with means for feeding the dispersing fluid tangentially at the infeed end of the
  • FIG. 1 shows a prior art moistening nozzle as disclosed in US 7820011 .
  • the nozzle has a frame 1 and a water nozzle 2 connected to the inside of the frame 1 with a threaded joint 17. Inside the frame 1 is also arranged an air nozzle 3 such that the water nozzle 2 and the air nozzle 3 are concentric.
  • the air nozzle 3 is secured to the frame 1 with a securing nut 4 that is connected to the exterior of the frame 1 with a threaded joint 18.
  • the water nozzle 2 includes a water connector 5 to which water is fed through a pipe or a hose or the like. From the water connector 5, the water flows out of the water nozzle through a water duct 6.
  • an air connector 7 to which a pipe or a hose or the like is connected for feeding air to the moistening nozzle.
  • Water is fed into the moistening nozzle, i.e., in the middle of the moistening nozzle, from the rear part thereof, and air is fed into the moistening nozzle from the side of the moistening nozzle.
  • Air is conducted from the air connector 7 to an air chamber 8 arranged around a shaft 14 of the water nozzle. From the air chamber 8, the air flows axially towards the air nozzle 3 through apertures 9 in the frame 1.
  • the air nozzle 3 comprises an internal thread 10 which is provided on the inner surface of the air nozzle 3 and by means of which the air is brought into swirling motion.
  • the air in swirling motion thus flows through an air gap 19 in the moistening nozzle to surround the water supplied from the water nozzle 2, whereby the mixture of water and air forms water mist. Due to the swirling motion, the water mist forms an even cone-shaped spray.
  • the air nozzle 3 is arranged inside the frame 1 in such a way that the air nozzle is positioned in place against a control surface 11 of the air nozzle inside the frame 1.
  • the control surface 11 of the air nozzle is located around the central axis in the circumferential direction.
  • the water nozzle 2, in turn, is positioned in place against a first control surface 12 of the water nozzle provided on the inner surface of the frame 1.
  • the control surface 11 of the air nozzle and the first control surface 12 of the water nozzle can be provided with one attachment of a machining piece on the frame 1, whereby they can be made concentric with close tolerance and the air nozzle 3 and the water nozzle 2 can be mutually centered with very good accuracy.
  • the frame 1 of the moistening nozzle are provided second and third control surfaces 15, 16 of the water nozzle to fit the water nozzle accurately into place.
  • Fig. 2 shows schematically a cross-sectional view of an embodiment of the nozzle of the invention.
  • the nozzle 20 comprises a housing having a first longitudinal central channel 24 for the fluid to be sprayed and a second coaxially extending outer channel 21 for a dispersing fluid.
  • the velocity vector of the fluid to be sprayed exiting from the opening of the first channel mainly has an axial component, whereas the velocity vector of the dispersing fluid exiting from the opening of the second channel has both rotational and axial components.
  • the nozzle 20 is provided with means 25 for feeding the dispersing fluid tangentially at the infeed end of the second channel 21.
  • the infeed end may have a feed chamber 26 into which the dispersing fluid is first fed tangentially to cause the dispersing fluid rotate therein and to enter therefrom to the second channel 21 in rotational motion. It is also possible to arrange the tangential feed of the dispersing fluid directly to the second channel at its infeed end without the separate feed chamber.
  • the second channel has inner 22 and outer 23 walls defining an annular space therebetween, the space tapering towards the exit of the channel such that the rate between the rotational and axial components of the velocity of the dispersing fluid increases before it leaves the channel and contacts the fluid to be sprayed.
  • R1 and R2 show the radius of the second channel at different locations showing that the radius decreases towards the exit end of the channel.
  • Fig. 3 shows a variation of the embodiment of fig. 2 .
  • the nozzle 30 differs from the nozzle 20 of fig. 2 in that the second channel 31 has a constant cross-sectional area. This is achieved by having the inner surface 32 taper more steeply towards the exit of the second channel than the outer surface 33.
  • D refers to the diameter of the inner surface 32 and D' to the diameter of the outer surface on a plane normal to the longitudinal central axis of the nozzle 30.
  • the area of the channel 31 is thus ⁇ (D 2 - D' 2 )/4.
  • the nozzle 30 is provided with means 35 for feeding the dispersing fluid tangentially at the infeed end of the second channel 31.
  • the infeed end may have a feed chamber 36 into which the dispersing fluid is first fed tangentially to cause the dispersing fluid rotate therein and to enter therefrom to the second channel 31 in rotational motion. It is also possible to arrange the tangential feed of the dispersing fluid directly to the second channel at its infeed end without the separate feed chamber.
  • the cross-sectional area may also be something between the embodiments of Figs. 2 and 3 , or even increasing, depending on the desired manner of selecting the said ratio of rotational velocity and axial velocity.
  • Fig. 4 shows exemplary dimensioning of the second channel in the nozzle of the present invention.
  • D2 is defined by the dimensions of the first channel for the fluid to be sprayed.
  • the diameter of the inner channel is usually in the order of about 4 mm.
  • the diameter of the inner channel is preferably in the range of 2 to 8 mm and the diameter D2 of the second channel in the range of 4 to 12 mm, preferably in the range of 6 to 9 mm.
  • D1 is preferably about (1,3 - 4)*D2. More preferably D1 is about (1,5 - 2,5)*D2 and H1 is preferably 0,5 - 3 mm (0,8 - 1,5 mm).
  • H2 is preferably about (1 - 4)*H1, more preferably about (1,5 - 2,5)*H1).
  • L is preferably 5 - 50 mm (more preferably 10 - 30 mm).
  • the conicity ⁇ is preferably in the range of 30° - 85°, more preferably in the range of 45° - 75°, still more preferably in the range of 55° - 65°.
  • the opening angle ⁇ is preferably in the range of 0° - 15° (more preferably in the range of 1°-5°).
  • Table 1 shows the results of the calculations.
  • Table 1 Prior art Nozzle according to the invention Nozzle according to the invention Nozzle according to the invention Nozzle according to the invention Tapering channel Constant cross-sectional area Tapering channel Constant cross-sectional area Constant cross-sectional area Air feed pressure 0.300 bar 0.300 bar 0.300 bar 0.015 bar 0.015 bar 0.075 bar Amount of air from nozzle 8 kg/h 11 kg/h 16 kg/h 8 kg/h 11 kg/h 8 kg/h Rotational velocity of air 50 m/s 100 m/s 165 m/s 70 m/s 115 m/s 80 m/s Axial velocity of air 155 m/s 145 m/s 100 m/s 100 m/s 70 m/s 50 m/s Rotational velocity/axial velocity 0.3 0.7 1.6 0.7 1.6 1.6
  • the axial velocity of air means the velocity of air in the direction of the liquid jet. All the velocities in the table have been measured at the point where the air exits from the nozzle, that is, immediately before the air and the liquid come into contact.
  • the rotational velocity of the air at the same feed pressure is about twice or three times higher with the nozzles of the invention than with the prior art nozzle.
  • the last line in the table 1 shows the ratio of rotational velocity and axial velocity which is clearly increased from that of the prior art, that is, with the nozzle according to the invention, the velocity of air is "transferred" from axial velocity to rotational velocity compared with the prior art. This ratio can be adjusted/selected as desired through the tapering/opening of the cross-sectional area of the tapered channel.
  • the velocity vectors of air are shown schematically by the arrows V, V1 and V2, the ratio of rotational velocity and axial velocity being 0.3, 0.7 and 1.6, respectively. These vectors depict the angle of ascent of the air which is moving spirally.

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EP13152188.2A 2013-01-22 2013-01-22 Buse de pulvérisation et procédé de pulvérisation de fluides dans des gouttelettes pour traiter des bandes fibreuses Withdrawn EP2757193A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP13152188.2A EP2757193A1 (fr) 2013-01-22 2013-01-22 Buse de pulvérisation et procédé de pulvérisation de fluides dans des gouttelettes pour traiter des bandes fibreuses

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP13152188.2A EP2757193A1 (fr) 2013-01-22 2013-01-22 Buse de pulvérisation et procédé de pulvérisation de fluides dans des gouttelettes pour traiter des bandes fibreuses

Publications (1)

Publication Number Publication Date
EP2757193A1 true EP2757193A1 (fr) 2014-07-23

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EP13152188.2A Withdrawn EP2757193A1 (fr) 2013-01-22 2013-01-22 Buse de pulvérisation et procédé de pulvérisation de fluides dans des gouttelettes pour traiter des bandes fibreuses

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EP (1) EP2757193A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105088852A (zh) * 2015-07-08 2015-11-25 华南理工大学 一种防止冷凝水滴落的蒸汽箱及方法

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE952765C (de) * 1954-03-16 1957-04-04 V I B Appbau Ges M B H Vorrichtung zum Zerstaeuben und Auftragen von fluessigen Medien auf trockene Faserstoff-, insbesondere Papierbahnen
FR1510504A (fr) * 1967-02-06 1968-01-19 Sames Mach Electrostat Perfectionnements au recouvrement électrostatique, en particulier à l'humidification du papier
US4946101A (en) * 1988-06-10 1990-08-07 V.I.B. Apparatebau Gmbh Atomizer
WO2003035271A1 (fr) * 2001-10-22 2003-05-01 Abb Ltd. Buse d'atomisation destinee a des rinceurs de rehumidification
US6969012B2 (en) 2002-01-24 2005-11-29 Kangas Martti Y O Low pressure atomizer for difficult to disperse solutions
JP2006247619A (ja) * 2005-03-14 2006-09-21 Sony Corp ２流体ノズル及び洗浄装置
JP2008018400A (ja) * 2006-07-14 2008-01-31 Ikeuchi:Kk 二流体ノズル
US7820011B2 (en) 2004-07-30 2010-10-26 Metso Automation Oy Moistening nozzle of a paper web

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE952765C (de) * 1954-03-16 1957-04-04 V I B Appbau Ges M B H Vorrichtung zum Zerstaeuben und Auftragen von fluessigen Medien auf trockene Faserstoff-, insbesondere Papierbahnen
FR1510504A (fr) * 1967-02-06 1968-01-19 Sames Mach Electrostat Perfectionnements au recouvrement électrostatique, en particulier à l'humidification du papier
US4946101A (en) * 1988-06-10 1990-08-07 V.I.B. Apparatebau Gmbh Atomizer
WO2003035271A1 (fr) * 2001-10-22 2003-05-01 Abb Ltd. Buse d'atomisation destinee a des rinceurs de rehumidification
US6969012B2 (en) 2002-01-24 2005-11-29 Kangas Martti Y O Low pressure atomizer for difficult to disperse solutions
US7820011B2 (en) 2004-07-30 2010-10-26 Metso Automation Oy Moistening nozzle of a paper web
JP2006247619A (ja) * 2005-03-14 2006-09-21 Sony Corp ２流体ノズル及び洗浄装置
JP2008018400A (ja) * 2006-07-14 2008-01-31 Ikeuchi:Kk 二流体ノズル

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105088852A (zh) * 2015-07-08 2015-11-25 华南理工大学 一种防止冷凝水滴落的蒸汽箱及方法

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