METHOD AND APPARATUS FOR COATING A SUBSTRATE

Abstract: Apparatus and method for directing a constant velocity laminar flow of a fluid along a surface of a planar substrate. The apparatus comprises a plurality of serially arranged, individual passageways (38, 44, 50, 60, 64, 66, 80, 82) interconnecting an inlet (30) and an outlet (34). The inlet is adapted to be connected to a supply of fluid, while the outlet is positioned adjacent the surface of the substrate for directing the uniform laminar flow of fluid onto the substrate surface. The individual passageways are adapted to vary the velocity of the fluid as it passes through the passageways to ensure that a laminar flow of constant velocity is produced along the surface of the substrate. In the preferred embodiment of the invention, the apparatus is utilized to apply a metal oxide coating to a sheet of moving glass. In these instances, the outlet is an elongate nozzle extending transversely relative to the path of the moving glass to enable a gaseous reactant utilized to form the metal oxide coating to be applied across the entire width of the glass sheet. In one embodiment of the invention, the individual passageways are alternating converging and diverging passageways which function to evenly distribute the fluid within the passageways such that the fluid exits the elongate outlet at a relatively constant velocity to produce a uniform laminar flow of the gaseous reactant across the glass sheet.

Description: Description Method and Apparatus for Coating a Substrate Technical Field The present invention relates generally to an apparatus and method for directing a laminar flow of a fluid along the surface of a planar substrate. In particular, the apparatus of the present invention is utilized to coat a substrate by means of a chemical vapo deposition process by directing a laminar flow of a gaseous reactant mixture toward the surface of the substrate to cause the reactant mixture to deposit the desired coating on the substrate surface. Background Art Chemical deposition processes such as pyrolytic processes and hydrolytic processes are well known in the art of coating substrates. The physical form of the coating reactants employed in such processes may be liquid, vapor, liquids or solids dispersed in gas mixtures, aerosols, or vaporized or vaporous coating reactants dispersed in gas mixtures. One of the problems associated with coating substrates by directing a gaseous reactant mixture along substrate surface to deposit the coating relates to maintaining a uniform thickness of the coating along the substrate. In certain instances, such as the applicatio of a reflective metal oxide coating to a sheet of glass, the requirement that the coating have a uniform thicknes is especially important since small variations in the coating thickness can result in the glass sheet having poor optical quality. For example, variations in thickness of the metal oxide coating of one millionth of an inch can produce an undesirable optical effect or an unaesthetic appearance in the glass. Generally, in orde to produce a coating having a constant thickness, it is necessary that the gaseous reactant mixture be uniformly applied to the entire sheet of glass. Disclosure of Invention The present invention relates to an apparatus and method for directing a laminar flow of constant velocity fluid toward the surface of a substrate. In the preferr embodiment, the apparatus is utilized to apply a metal oxide coating to a sheet of moving glass by directing a laminar flow of a gaseous reactant mixture onto the surface of the glass, thereby causing the reactant mixtu to deposit the desired coating on the glass surface. Th " pparatus produces the laminar flow by supplying the gaseous reactant at a constant velocity throughout the length of an elongate outlet nozzle positioned transversely to the direction of travel of the glass sheet. More specifically, the apparatus comprises a plurality of serially arranged, individual passageways interconnec ing an inlet means and an outlet means. The inlet means is adapted to be connected to a supply of fluid, while the outlet means includes an opening positioned adjacent the surface of the substrate for directing the laminar flow of fluid onto the substrate surface. Each of the individual passageways includes a portion having a cross sectional area different from the OMP cross sectional area of each of the adjacent ones of th passageways for causing the velocity of the fluid flowi through the passageways to vary. It has been found tha causing the velocity of the fluid to change as it flows through' the passageways enables the fluid to be uniform distributed throughout the passageways such that the fl is delivered from the opening of the outlet means at a predetermined constant velocity to produce a laminar fl on the subs rate surface. Several embodiments of the present invention have been proposed for producing the velocity changes in the fluid as the fluid flows through the individual passageways. In one embodiment, the individual passageways are formed as alternating converging and diverging passageways which function to alternately accelerate and decelerate the fluid as it passes throug the passageways. In an alternate embodiment of the invention, the series of individual passageways alternat between a passageway having a uniform first prede ermine cross sectional area and a passageway having a second uniform predetermined cross sectional area smaller than the first predetermined area, thereby alternately decreasing and increasing the velocity of the fluid as i flows through the passageways. In a further embodiment the invention, the individual passageways comprise a series of passageways each having a uniform cross sectional area, wherein the area of each passageway is smaller than the area the preceding adjacent passageway. In this embodiment, the velocity of fluid is continually increased as it passes from one passageway to another passagewa . Brief Description of the Drawings The above, as well as other advantages of the prese invention, will become readily apparent to one skilled i the art from reading the following detailed desc-ription conjunction with the attached drawings, in which: CMP ' ■ ,. IP Fig. 1 is a cross-sectional schematic view illustrating one embodiment of the apparatus of the present invention utilized to apply and withdraw a lamin flow of constant velocity fluid along the surface of a subs trate; Fig. 2 is a top plan view of the apparatus shown in Fig. 1 taken along the line 2-2 of Fig. 1; Fig. 3 is a cross-sectional schematic view of an alternate embodiment of the apparatus of the present inven ion; Fig. 4 is a cross-sec ional schematic view of a further alternate embodiment of the apparatus of the present invention; and Fig. 5 is an alternate embodiment of the present invention wherein two of the apparatuses shown in Fig. 1 are positioned adjacent one another for directing two individual gaseous reactants toward the surface of a subs trate. Modes for Carrying Out the Invention Referring to Fig. 1, there is shown a schematic diagram of an apparatus 10 adapted to direct a laminar flow of a fluid onto an upper surface 12a of a planar substrate 12. The substrate 12 is supported by rollers and is conveyed along a generally linear path (as represented by direction arrow P) by suitable conveyor means (not shown). In the preferred embodiment of the invention, the apparatus 10 is utilized to apply a coati to the surface 12a by means of a chemical vapor depositi process. Thus, the fluid is typically a gaseous reacta mixture which reacts to deposit a coating on the surface 12a. For example, the substrate 12 can be a sheet of glass and the gaseous reactant mixture can react to for reflective metal oxide coating on the surface 12a. While it will be appreciated that the apparatus 10 can be formed in a variety of shapes, the preferred embodiment of the apparatus 10 is in the form of a generally rectangular, elongate box having spaced apart generally parallel sidewalls 16 and 18, an upper wall 20 a lower wall 22, and spaced apart end walls 24 and 26 (shown in Fig. 2), all of which cooperate to define a 5 generally enclosed chamber 28. The apparatus includes at least one inlet 30 centrally located along one longitudinal edge of the upp wall 20. The inlet 30 is connected to receive a supply fluid from a fluid source 32. It will be appreciated .10 that, in some instances, it may be desirable to provide plurality of inlets for introducing the fluid into the apparatus 10. Also, it is not necessary that the inlet be located along the edge of the upper wall 20. For example, the inlet can be located in the sidewall 16. 15 As will be discussed, the apparatus 10 is provided with a plurality of wall members mounted within the chamber 28 which cooperate to direct the fluid through a series of alternating converging and diverging passageways. The alternating converging and diverging 20 passageways function to evenly distribute the fluid with the passageways throughout the entire longitudinal lengt of the passageways . such that the fluid exits an elongate outlet nozzle 34 at a relatively constant velocity to produce a uniform laminar flow of the fluid along the 25 surface 12a. The outlet nozzle 34 is in the form of an elongate slot having a predetermined width W (shown in Fig. 1) and extending a distance L (shown in Fig. 2) alo one longitudinal edge of the lower wall 22. As shown in Fig. 2, the outlet nozzle 34 is located generally 30 transversely to the direction of travel of the substrate 12. A wall member 36 is generally parallel with the sidewalls 16 and 18 and extends longitudinally within th chamber 28. The upper edge of the wall member 36 is .35 attached to the lower surface of the upper wall 20, whil ; the side edges of the wall member 36 are connected to th I inner surfaces of the end walls 24 and 26. The wall me ber 36 cooperates with the sidewall 16 to define a downwardly extending inlet passageway 38. While the inl passageway 38 is shown in the drawings as having a generally uniform cross-section, it will be appreciated that the wall member 36 can be positioned relative to th sidewall 16 in such a manner that the passageway 38 can either converging or diverging. Typically, the spacing between the lower edge of the wall member 36 and the upp surface of the lower wall 22 (distance A in Fig. 1) is less than the spacing between the sidewall 16 and the wa member 36 (distance B) to define a converging passageway 40. Thus, the fluid, as it exits the inlet passageway 3 converges and accelerates as it enters the passageway 40 A wall member 42 extends longitudinally within the chamber 28 and has its lower edge connected to the upper surface of the lower wall 22 and its side edges connecte to the inner surfaces of the end walls 24 and 26. The wall member 42 is positioned within the chamber 28 such that it forms an angle S relative to a reference line generally perpendicular to the lower wall 22. The lower portion of the wall member 42 is spaced from the wall member 36 by a distance C, which is typically equal to t distance A, while the upper portion of the wall member 4 is spaced from the wall member 36 by a distance D, which is greater than the distance C. The wall member 42 cooperates with the wall member 36 to define an upwardly extending diverging passageway 44 with a generally increasing cross-sec ional area. Thus, once the fluid h converged and accelerated in the passageway 40, the flui will be caused to diverge and thus decelerate in the passageway 44. The upper end of the wall member 42 is spaced from the lower surface of the upper wall 20 by th distance A to define a converging passageway 46 which causes the fluid to accelerate as it enters the passagew 46. A wall member 48 extends longitudinally within the chamber 28 and has its upper edge connected to the lower OMPI surface of the top wall 20 and its side edges connected the inner surfaces of the end walls 24 and 26. The wal member 48 is positioned within the chamber 28 such that forms an angle T relative to a reference line generally perpendicular to the upper wall 20. Typically, the upp wall 20 is substantially parallel to the lower wall 22. The upper portion of the wall member 48 is spaced from upper edge of the wall member 42 by the distance C, whi the lower portion of the wall member 48 is spaced from lower portion of the wall member 42 by a distance E. T lower edge of the wall member 48 is spaced from the upp surface of the lower wall 22 by the distance A. The wa member 48 cooperates with the wall member 42 to define downwardly extending diverging passageway 50, and cooperates with the lower wall 22 to define a convergin passageway 52. It has been found that selecting angles and T such that the ratio between the dimensions C and is approximately one to four produces a diverging passageway with the desired decleration effects. In th embodiment of Fig. 1, the angles S and T are each approximately 5°. A pair of wall members 54 and 56 are mounted withi the chamber 28 in a manner similar to the wall member 42 while a wall member 58 is mounted in a manner similar to the wall member 48. The wall members 48 , 54, 56, and 58 cooperate to form additional diverging passageways 60,. 6 64, 66, and additional converging passageways 68, 70, an 72, all of which cooperate to alternately decelerate and accelerate the fluid stream. A pair of spaced-apart wall members 76 and 78 are positioned in generally parallel relationship with the sidewall 18 to define an upwardly extending outlet passageway 80 having a relatiely constant cross-section and a downwardly extending outlet passageway 82 having a relatively constant cross section similar in area to the cross-sectional ' area of the passageway 80. The lower en of the passageway 82 terminates at the outlet nozzle 34. OMPI Typically, the wall members 76 and 78 are spaced apart b the distance W, which represents the spacing between the wall member 78 and the sidewall 18. As the fluid exits the diverging passageway 64 (formed by wall members 56 a 76), the fluid converges in an area 83 and enters the outlet passageway 80. The constant cross sections of th passageways 80 and 82 function to stabilize the velocity of the fluid stream such that, when the fluid exits the outlet nozzle 34, the velocity of the fluid will be at a relatively constant level the entire length of the nozzl 34. Typically, the width W of the outlet nozzle 34 is substantially equal to the distances A and C. In some instances, when the overall length L (shown in Fig. 2) of the apparatus is relatively large, it may desirable to provide a plurality of spaced-apart support rods 84 which extend through suitable apertures formed i the wall members to maintain the predetermined spacing between the wall members. Also, in order to control the reaction time of the reactant substituents being applied to the substrate, an elongate vacuum device 86 may be disposed adjacent one side of the apparatus. The vacuum device 86 has an outl 87 suitably coupled to a vacuum source 88. An -elongate inlet slot 90 is provided in the vacuum device 86 to enable the controlled withdrawal of the substituents fro the zone between the outlet nozzle 34 and the device 86 enable more complete control over the process. As shown in Fig. 1, the vacuum device 86 can be constructed in a manner similar to the apparatus 10. It has been found that such a construction produces a uniform vacuum pull across the entire length of inlet slot 90. It should be noted that the present invention, in i broadest sense, encompasses an apparatus which directs a flow of a fluid through a series of individual passagewa which are adapted to cause a series of velocity changes the fluid as the fluid flows through the passageways. I has been discovered that causing the fluid to flow in su OMP a manner evenly distributes the fluid to an elongate outlet nozzle and enables a uniform laminar flow of constant velocity fluid to be applied to the surface of substrate. It is believed that treating the flow of fl in a manner as described above causes the molecules of t fluid to be evenly distributed throughout the length of the elongated outlet nozzle and causes the molecules to travel from the outlet nozzle in a generally parallel pa to one another and at a constant velocity. Consequentl a laminar flow of constant velocity fluid is produced. Generally, the velocity at which the fluid is delivered from the elongate nozzle is a function of the pressure at which the fluid is delivered into the inlet, and the overall dimensions at which the apparatus is constructed. The velocity at which the fluid is deliver from the outlet can be regulated by controlling the pressure at which the fluid is intro-duced into the apparatus or, alternatively, controlling the dimensions the apparatus . While the embodiment shown in Fig. 1 includes a series of alternating converging and diverging passagewa which causes the fluid to alternately accelerate and decelerate as it flows through the series of passageways it will be appreciated that the apparatus can be constructed in a different manner to achieve the desired velocity changes in the fluid as it travels through the passageways. For example, in Fig. 3, there is shown an alternate embodiment of an apparatus 100 which utilizes parallel, spaced apart relationship between the internal wall members to achieve the desired velocity changes in the fluid. In Fig. 3, the apparatus 100 is similar in external shape to the apparatus 10 of Fig. 1, and includes spaced apart generally parallel sidwalls 102 and 104, an upper wall 106 and a lower wall 108. The apparatus 100 includ an inlet 110 for introducing fluid into a downwardly extending inlet passageway 112 defined by a wall member -gTJlE OMPI 114 and the sidewall 102. The wall member 114 is generally parallel to the sidewall 102 and is spaced a distance X from the sidewall 102. The lower edge of the wall member 114 is spaced a distance Y from the upper surface of the lower wall 108. A wall member 116 extends upwardly from the bottom wall 108 and is generally parallel to the wall member 11 for defining an upwardly extending passageway 118. The wall member 116 is spaced a distance Y from the wall member 114 and has an upper edge which is spaced a distance Y from the lower surface of the top wall 106. Thus, the fluid as it exits the inlet passageway 112, mu converge and increase in velocity as it enters the passageway 118. It has been found that a ratio of four one between the distances X and Y provide the desired velocity changes in the fluid. A pair of wall members 114a and 114b extend downwardly from the top wall 106, while a pair of wall members 116a and 116b extend upwardly from the lower wal 108. Together, these wall members cooperate to form downwardly extending low velocity passageways and upward extending high velocity passageways similar to the passageways 112 and 118. A pair of wall members 120a an 120b .are positioned in a manner similar to the wall members 76 and 78 of the apparatus 10 in Fig. 1 to form outlet passageway of width Wl which distributes the flui from an outlet 122. Typically, the width Wl is substantially equal to the distance Y. Referring to Fig. 4, there is shown a further alternate embodiment of an apparatus 130 which can be us to provide the desired changes in velocity of the fluid it passes through a series of internal passageways. The apparatus 130 includes spaced apart parallel sidewalls 1 and 134, a top wall 136, and a lower wall 138. An inlet 140 is adapted to introduce a supply of fluid into a downwardly extending passageway 141 formed by a wall member 142 and the sidewall 132. The wall member 142 is generally parallel to the sidewall 132 and is spaced a distance Al from the sidewall. The lower edge of the w member 142 is spaced a distance Bl from the upper surfac of the lower wall 138. A wall member 146 is attached t the lower wall 138 and is spaced a distance Bl from the wall member 142 to define an upwardly extending passage 148. The upper edge of the wall member 146 is spaced a distance Cl from the lower surface of the top wall 136. A pair of wall members 142a and 142b extend downwardly from the top wall 136 ' and cooperate with wall members 146a and 146b which extend upwardly from the bottom wall 138 to define a series of upwardly extending and downwardly extending passageways which are spaced apart in such a manner to define individual passageways which decrease in cross sectional area as the passageway move from the inlet to the outlet. Thus, in Fig. 4, the dimensions Al through Gl represent decreasing distances. Such a construction causes the velocity of the fluid to continually increase as the fluid flows from one passageway to another. It has been found that satisfactory results are obtained by reducing the dimensions Al through Gl such that the ratio between the distances Al and Gl is approxima ely four to one. The apparatus 130 includes wall members 149a and 149b which form an outlet passageway of " width W2 similar to the outlet passageway of the apparatus of Fig. 1 for distributing the fluid from an outlet nozzle 150. In instances wherein more than one fluid or gaseous reactant is desired to be supplied to the surface of the substrate, the arrangement shown in Fig. 5 can be utilized. In this case, two apparatus 152 and 154, similar to the apparatus 10, are connected to receive a supply of fluid from first and second fluid sources 156 and 158, respectively. The apparatus 152 and 154 are positioned with their respective outlet nozzles 152a and 154a in adjacent relationship to one another. The outle nozzles 152a and 154a can be formed to direct the individual gaseous reactants in a path which intersect a the surfa.ce 12a of the substrate. Also, a pair of vacuu devices 160 and 162, similar in construction to the vacu device 86 of Fig. 1, are coupled to first and second vacuum sources 164 and 166 respectively, and can be positioned to control the withdrawal of the fluids from the surface of the substrate 12. The principles and mode of operation of the present invention have been illustrated and described in what is considered to represent its preferred embodiments. It should, however, be understood that the invention may be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.

Claims: AMENDED CLAIMS [received by the International Bureau on 10 January 1985 (10.01.85); original claims 1,12,18 and 21 amended; new claims 24-27 added; remaining claims unchanged (8 pages follow)] 1. (Amended) An apparatus for directing a laminar flow of constant velocity fluid toward a surface of a substrate comprising: inlet means adapted to communicate with a sourc of fluid ; outlet means spaced from said inlet means and having an outlet nozzle adapted to be positioned adjacent the surface of the substrate, said outlet nozzle defining an elongate opening extending a predetermined distance along the substrate; and a plurality of serially arranged individual passageways interconnecting said inlet means and sai outlet means, each of said individual passageways including a portion having a cross-sectional area different from the cross-sec iona1 area of a portion of each of the adjacent ones of said passageways causing the velocity of the fluid to vary as the fluid flows through said passageways and causing the fluid to be delivered from said outlet nozzle of sai outlet means in a uniform laminar flow of relatively constant velocity across the entire length of said elongate opening. 2. The apparatus defined in claim 1 wherein said serially arranged individual passageways include a first predetermined number of individual converging passageways and a second prede ermined number of individual diverging passageways, a separate one of said diverging passageways connected between adjacent ones of said converging passageways whereby the fluid is caused to accelerate in said converging passageways and to decelerate in said diverging passageways . OMPI A , WPO The apparatus defined in claim 2 wherein the ratio between the portion of said diverging passageways having the largest cross-sectional area to the portion of said converging passageways having the smallest cross-sectional area is approximately four to one. The apparatus defined in either claim 2 or 3 including at least five converging passageways and a least five diverging passageways. The apparatus defined in claim 1 wherein said individual passageways include a first group of passageways each having a portion of relatively uniform first predetermined cross-sectional area and a second group of passageways each having a portion of relatively uniform second predetermined- cross-sectional area different from the first predetermined area of said first group, a separate one of said first group of passageways connected between adjacent ones of said second group of passageways whereby the velocity of the fluid in sai first group of passageways is different from the velocity of the fluid in said second group of passageways . The apparatus defined in claim 5 wherein the ratio between said second predetermined area and said firs predetermined area is approximately four to one. The apparatus defined in claim 1 wherein each of sai serially arranged individual passageways includes a portion of relatively uniform cross-sectional area, the cross-sectional areas of each of said passageway progressively decreasing from said inlet means to said outlet means, whereby the velocity of the fluid is progressively increased as the fluid travels from -BUREA OMPI said inlet means to said outlet means. 8. The apparatus defined in claim 1 including an outer housing defining a chamber containing said individua passageways, said inlet means located proximate one end of said housing and said outlet means located proximate the opposite end of said housing. 9. The apparatus defined in claim 8 including a plurality of spaced apart wall members mounted withi said housing defining said passageways. 10. The apparatus defined in claim 9 wherein adjacent ones of said wall members are non-parallel to one another . 11. The apparatus defined in claim 1 wherein said outlet means includes an outlet passageway of a prede ermined length, said outlet passageway having subs antially uniform cross-section throughout the length of said outlet passageway causing the velocit of the fluid to stabilize at a constant level before the fluid is delivered from the opening of said outlet. 12. (Amended) A method of producing a uniform laminar flow of a fluid along the surface of a substrate traveling in a linear path comprising the steps of: (a) directing a fluid stream through a series of individual passageways causing the velocity of th fluid stream to vary as the fluid passes through the passageways to produce a uniform laminar flow of fluid; and (b) directing the uniform laminar flow of flui at a relatively constant velocity onto the surface o the substrate through the entire length of an elongate outlet slot positioned adjacent the surface of the substrate and extending along at least a portion of the substrate. 13. The method according to claim 12 including the step of stabilizing the fluid flow prior to being directe onto the surface. 14. The method according to claim 12 wherein step (a) includes causing the fluid stream to be alternately accelerated and decelerated. 15. The method according to claim 12 wherein step (a) includes causing the velocity of the fluid stream to be alternately increased to a first predetermined constant velocity and decreased to a second predetermined constant velocity as the fluid stream flows through the passageways. 16. The method according to claim 12 wherein step (a) includes causing the velocity of the fluid stream to be progressively increased as the fluid stream flows through the passageways. 17. The method according to claim 12 wherein step (a) includes causing the velocity of the fluid stream to stabilize at a constant level, thereby producing a uniform laminar flow of constant velocity fluid. 18. (Amended) An apparatus for withdrawing a fluid strea from a surface of a substrate comprising: outlet means adapted to be connected to a sourc of vacuum; inlet means having an inlet slot adapted to be positioned adjacent the surface of the substrate to receive the fluid stream, said inlet slot defining a elongate opening extending a predetermined distance along the substrate; and -BUREAI OMPI a plurality of serially arranged individual passageways interconnecting said inlet mean's and sai outlet means, each of said individual passageways including a portion having a cross-sectional area different from the cross-sectional area of a portion of each of the adjacent ones of said passageways for causing the velocity of the fluid to vary as the fluid flows through said passageways and causing the fluid to be withdrawn from the surface in a uniform manner throughout the entire length of said elongate opening. 19. The apparatus defined in claim 18 including an outer housing defining a chamber containing said individua passageways, said inlet means located proximate one end of said housing and said outlet means located proximate the opposite end of said housing. 20. The apparatus defined in claim 19 including a plurality of spaced apart wall members mounted withi said housing defining said passageways. 21. (Amended) An apparatus for directing a laminar flow of constant velocity fluid toward a surface of a sheet of glass traveling in a linear path, said apparatus comprising: inlet means adapted to communicate with a sourc of fluid; an outlet means spaced from said inlet means an having an outlet nozzle adapted to be positioned adjacent the surface of the glass, said outlet nozzl defining an elongate opening extending a predetermined distance across the glass generally transversely relative to the linear path of the glass ; and a plurality of serially arranged individual passageways interconnecting said inlet means and sai ' BU EA OMPI AV M PO outlet means, each of said individual passageways including a portion having a cross-sectional area different from the cross-sectional area of a portion of each of the adjacent ones of said passageways causing the velocity of the fluid to vary as the fluid flows through said passageways and causing the fluid to be delivered from said outlet nozzle in a laminar flow of relatively constant velocity across the entire length of said elongate opening. 22. The apparatus defined in claim 21 including vacuum means for withdrawing the flow of fluid from the surface of the glass. 23. The apparatus defined in claim 22 wherein said vacuu means includes outlet means adapted to be connected to a source of vacuum, inlet means adapted to be positioned adjacent the surface of the substrate to receive the flow of fluid, said inlet means includin an opening extending generally transversely relative to the linear path of the glass, and a plurality of serially arranged individual passageways interconnecting said inlet means and said outlet means, each of said individual passageways including a portion having a cross-sectional area different from the cross-sectional area of a portion of each o " he adjacent ones of said passageways for causing th velocity of the fluid to vary as the fluid flows through said passageways, whereby the fluid is withdrawn from the surface of the glass in a uniform manner. 24. (New) An apparatus for directing a laminar flow of constant velocity fluid toward a surface of a substrate comprising: inlet means adapted to communicate with a sourc of fluid ; - U EA OMPI outlet means spaced from said inlet means and having an outlet nozzle adapted to be positioned adjacent the surface of the substrate, said outlet nozzle defining an elongate opening extending a predetermined distance along the substrate; and a plurality of serially arranged individual passageways interconnecting said inlet means and sai outlet means, each of said passageways having an elongate portion extending substantially parallel to and substantially the same distance as said elongate opening causing the fluid to be delivered from said outlet nozzle of said outlet means in a uniform laminar flow of relatively constant velocity across the entire length of said elongate opening. 25. (New) A method of producing a uniform laminar flow o a fluid along the surface of a substrate traveling i a linear path comprising the steps of: (a) directing a fluid stream through a series of individual passageways causing the velocity of th fluid stream to vary as the fluid passes through the passageways to produce a uniform laminar flow of fluid; and (b) directing the uniform laminar flow of fluid of relatively constant velocity onto the surface of the substrate through the entire length of an elongate outlet slot positioned adjacent the surface of the substrate and extending along at least a portion of the substrate transversely relative to the linear path of the substrate. 26. (New) The apparatus as defined in claim 22 wherein said vacuum means is a first vacuum means positioned on one side of said outlet means and including a second vacuum means positioned on the opposite side of said outlet means for assisting said first vacuum means in the withdrawal of the flow of fluid from the "B JREA OMPI surface of the glass 27. (New) The apparatus as defined in claim 23 wherein * said vacuum means is a first vacuum means and said inlet means of said first vacuum means is positioned on one side of said outlet means for delivering the flow of fluid, said apparatus including a second vacuum means having an outlet means adapted to be connected to a source of vacuum, inlet means adapted to be positioned adjacent the surface of the substrate on the opposite side of said outlet means for delivering the flow of fluid to receive the flow of fluid, said inlet means including an opening extending generally transversely relative to the linear path of the glass, and a plurality of seriall arranged individual passageways interconnec ing said inlet means and said outlet means, each of said individual passageways including a portion having a cross-sectional area different from the cross-sectional area of a portion of each of the adjacent ones of said passageways for causing the velocity of the fluid to vary as the fluid flows through said passageways, whereby the fluid is withdrawn from the surface of the glass in a uniform manner.

Inventors: ALBACH EBERHARD R, HOFER PETER H, ALBACH, EBERHARD, R., HOFER, PETER, H.
Applicants: LIBBEY OWENS FORD CO, LIBBEY-OWENS-FORD COMPANY
Application year: 1984
Main classification: C23C11
IPC codes: C03C17, C23C16