US3889636A - Coating of substrates with particle materials - Google Patents

Abstract

Apparatus for electrostatically applying a coating of a particle material to a substrate surface to which a settable adhesive has been applied, including a container for the particle material which can pass gravitationally to a power-driven agitating and metering device and through an electrostatically chargeable electrode from which the charged particle material can then pass downwardly through a main discharge opening to the substrate surface, or said main discharge opening can be closed and the charged particle material can then be fed by the agitating and metering device to an air operated injector device from which the particle material can be delivered through a flexible pipe to a portable handle device to which different subsidiary discharge heads can be applied and electrostatically charged electrodes are positioned at or adjacent subsidiary discharge head openings to again charge or boost the charge applied to the particle material prior to discharge towards the substrate surface.

Description

United States Patent 1191 Smith 1 1 COATING OF SUBSTRATES WITH PARTICLE MATERIALS Willoughby Arthur Smith, The Mead, Sidcot, Winscombe, England [22] Filed: Dec. 29, 1972 [21] Appl. No; 319,381

[76] Inventor:

3,327,948 6/1967 Gignouxmu 239/15 3,339,840 9/1967 Point i i i 239/3 3,342,415 9/1967 Point i 239/15 3,347,469 10/1967 ROSS 6t 21., 118/627 X 3,496,911 2/1970 Chmelar 118/621 3,498,540 3/1970 Adams... 239/15 3,551,178 12/1970 Chmelar 118/629 1 June 17, 1975 Angelico 239/3 Luderer ct a1. 239/3 Primary ExaminerMervin Stein Assistant E.ram1'ner-Leo Millstein Attorney, Agent, or Firm-Holman & Stern [57] ABSTRACT Apparatus for electrostatically applying a coating of a particle material to a substrate surface to which a settable adhesive has been applied, including a container for the particle material which can pass gravitationally to a power-driven agitating and metering device and through an electrostatically chargeable electrode from which the charged particle material can then pass downwardly through a main discharge opening to the substrate surface, or said main discharge opening can be closed and the charged particle material can then be fed by the agitating and metering device to an air operated injector device from which the particle material can be delivered through a flexible pipe to a portable handle device to which different subsidiary discharge heads can be applied and electrostatically charged electrodes are positioned at or adjacent subsidiary discharge head openings to again charge or boost the charge applied to the particle material prior to discharge towards the substrate surface.

6 Claims, 6 Drawing Figures 1 COATING OF SUBSTRATES WITH PARTICLE MATERIALS BRIEF SUMMARY OF THE INVENTION According to the present invention apparatus for electrostatically applying a coating of a particle material to a substrate surface to which a settable adhesive has been applied, is of the kind comprising a container for a stock of particle material, a main discharge head affording a main discharge head opening, an electrostatic generator, an electrode connected to the electrostatic generator so as to be charged thereby and disposed between the container and the discharge head opening to charge the particle material prior to discharge thereof through said opening wherein are the improvements comprising a metering device disposed between the container and the discharge head opening and connected to power operated driving means whereby the metering device is driven to accurately regulate the flow of particle material to the main discharge head opening in a uniform stream.

The metering device may comprise a rotatably mounted paddle having blades between which are formed measuring chambers for the particle material.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be more particularly described by way of example with reference to the accompanying drawings in which:

FIG. 1 is a part-sectional side view of a floor supported part of the apparatus including a main discharge head,

FIG. 2 is a sectional plan view of FIG. 1 on the lines 2-2 thereof,

FIG. 3 is a sectional side view on an enlarged scale of an injector device for propelling the particle material,

FIG. 4 is a sectional side view on an enlarged scale of a handle device for attachment thereto of a subsidiary discharge head,

FIG. 5 is a sectional side view of one subsidiary discharge head, and

FIG, 6 is a side view of a further subsidiary discharge head.

The floor supported part of the apparatus is indicated at 10 in FIG. 1 and comprises aframe 11 supported on floor engaging wheels or castors l2 and supported by the frame at one end thereof is acylindrical container 14 of which the longitudinal axis A-A is vertically disposed and at the top of the container is a removable perforate orimperforate lid 16 which can be removed to enable particle material such as fibres or granules such as of cork, wood chips, sand or other particle materials to be placed in the container after which the lid is replaced. At the lower end of thecontainer 14 is ahorizontal metal electrode 18 which is of openwork mesh formation of such dimensions as to resist the easy passage therethrough whilst, however, permitting the passage therethrough. of the selected particle material. Theelectrode 18 is connected by an electricallyconductive lead 20 to anelectrostatic generator unit 22 supported at the other end of the frame and suitably adapted to be connected to a mains electric supply source.

An imperforate blanking panel or closure means 24 can be removably secured to the lower end of thecontainer 14 which is provided with a turn-button 26 and asocket 27 to be engaged by atongue 29 of the panel which can be engaged by said turn-button so as to close the lower end of the container below theelectrode 18 and saidblanking panel 24 can be removed after manual release of the turn-button so that the lower end of thecontainer 14 can form a main discharge head indicated generally at 28 and having a main discharge head opening 31.

Ahorizontal platform 30 of the frame extends partially into thecontainer 14 and supports anelectric motor 32 which is arranged to drive, at variable speeds, avertical spindle 34 of which the axis is co-axial with the vertical axis AA of thecontainer 14 and supported at the lower end of thespindle 34 is a combined agitating and metering device in the form of arotatable paddle 35 and composed of four radially disposed paddles orblades 36 which are equiangularly spaced apart and each blade comprises arigid mounting strip 38 to which is secured a rubber or otherflexible wiper blade 40 of which the lower portion extends below the mounting strip and the lower horizontal edge of the lower portion wipes over in contact with or closely adjacent themesh electrode 18. Thus four equal substantially sector-shaped measuring chambers 42 are provided between the blades of the paddle to receive the particle material fed into thecontainer 14.

Theelectric motor 32 and the upper part of thespindle 34 are separated from thecontainer 14 by an imperforateprotective cover 43.

An opening orport 44 is formed in a side wall of thecontainer 14 adjacent the lower end thereof and, at least in main, is below the upper horizontal edges of thepaddles 36 so that said opening or port is disposed horizontally opposite themeasuring chambers 42 as thepaddles 36 sweep across said opening or port in fairly close proximity thereto. The opening orport 44 can be closed by a control means in the form of a verticallymovable slide 46 when said slide is manually moved downwardly and said port can be opened by manually moving theslide 46 upwardly in which upper position the opening or port is placed in communication with the interior of thechamber 14.

In order to apply a coating of particle material to a substrate surface such as thefloor surface 48 or a sheet of any suitable material resting thereon, said surface has applied thereto a suitable settable adhesive and, after thecontainer 14 has been at least partially filled with the particle material and theblanking panel 24 has been removed and the opening orport 44 has been closed, theelectric motor 32 is started whereby the agitating andmetering device 35 is rotated at a speed adjusted to suit the particular particle material and theelectrode 18 is electrostatically charged and the particle material passes downwardly under gravitational compulsion through theelectrode 18 so that a stream of electrostatically charged particles pass vertically downwardly and are attracted to thesubstrate surface 48 so as to coat said surface and form a part thereof after the adhesive has set. The entire substrate surface can easily be coated with the particle material by manually propelling the ground supportedapparatus 10 over said surface by handle means 49.

In order to apply a coating of a particle material to a substrate surface, after a settable adhesive has been applied thereto, such as for example a vertical wall surface or a ceiling surface, the portable subsidiary discharge head illustrated in FIG. 6 may be employed.

For this purpose there is mounted in the floor supportedpart 10 an air operatedinjector device 50, see FIGS. 1 and 3, which comprises atubular nozzle 51 which is screwed at one end into thecontainer 14 and the bore of the nozzle affords the opening orport 44. The other end of thenozzle 51 is externally convergent, as indicated at 52, in an arcuate manner and an internally screw-threadedsleeve 53 is engaged with an ex ternally screw-threaded part of thenozzle 51 so that anannular suction chamber 54 is provided within the sleeve and surrounding theconvergent part 52 of the nozzle. Asoutlet pipe 55 is screwed into thebush 53 and is adjusted longitudinally thereof and locked in po sition by a lock-nut 56 so as to leave agap 57 between thenozzle 51 and theoutlet pipe 55 and the width of saidgap 57 can be adjusted to suit various circumstances including the nature of the particle material being used.

An inlet nipple S9 is screwed into thesleeve 53 so that the bore of the nipple communicates with theannular suction chamber 54 and said nipple is connected by aflexible hose 58 to a power operated air compressor indicated at 159 mounted on theplatform 30 of the frame ll so that a current of air under pressure can be fed into theair injector device 50 and the air passes around thechamber 54 and is directed by theconvergent part 52 of the nozzle through thegap 57 and into the bore of theoutlet pipe 55 whereby suction is cre ated in the bore of thenozzle 51 and thus at the opening orport 44 so that particle material can be drawn into the injector device from thecontainer 14 when theslide 46 has been manually moved upwardly into a position opening saidport 44 and theblanking panel 24 has been secured to the lower end of saidcontainer 14 to close the main discharge head opening 31. During the suction effect exerted by theinjector device 50 on the particle material in thecontainer 14, the combined agitator andmetering device 35 is rotated at a suitable speed for the material so that said material is agitated and delivered to the opening orport 44 in a metered or controlled manner at a constant rate and before enter ing the opening orport 44, the particle material is electrostatically charged by reason of its proximity to theelectrode 18.

Theoutlet pipe 55 of theinjector device 50 has connected thereto one end of acircular pipe 60, see more particularly FIG, 1, of which oneend 61 extends beyond theframe 11 and which end forms a spigot coupling end to detachably receive asocket coupling end 62 of aflexible hose 63, see also FIG. 4, which at its other end has mounted thereon atubular socket handle 64 of a handle device and through which atubular extension 65 or connection part of thehose 63 extends and saidpipe 60 andhose 63 form a connecting passage. At one end of theextension 65, which extends beyond thehandle 64, there is mounted externally thereon an electrostatic connecting ring orelectrode 66 which is connected to alead 67 which is mounted on the exterior of theextension 65 and of thehose 63 and at its other end can be detachably connected by a connection diagrammatically indicated at 68 to alead 69 which is mounted on the exterior of thetube 60 and is connected to theelectrostatic generator 22. Thus theleads 67 and 69 are supported by thehose 63 andtube 60 respectively and can be electrically connected together and disconnected by simple acts of connecting thehose 63 to thepipe 60 and disconnecting said hose and pipe respectively.

Secured to thesocket handle 64 is ahousing 70 to which the socket handle is earthed at 71 and supported by thehousing 70 is a manuallyrotatable clamping screw 72 of which theinner end 73 enters thesocket handle 64 to clamp onto a feed tube orconnection part 74, see FIG. 5, of asubsidiary discharge head 75 of the manually supported apparatus part previously referred to, after saidtube 74 has been inserted over thering 66 andextension tube 65 into thesocket handle 64 until the outer end of thetube 74 abuts astop shoulder 76 in the socket handle and in which position the electrostatic connectingring 66 contacts a connecting end of alead 78 at the inner end of thetube 74.

The inner end of thefeed tube 74 is secured in acylindrical wall 79 of thesubsidiary discharge head 75 which is closed at one end by anend plate 82 and at its other end provides a subsidiary discharge head opening 83 across which extends ametal electrode 84 of openwork mesh formation and connected to thelead 78. Spaced a small distance inwardly from theelectrode 84 is abrush 86 which is in the form of a circular disc and of which the bristles extend from a backing pad towards theelectrode 84 and said brush constitutes a discharge agitating means for the particle material and is secured to one end of aspindle 88 adapted to be rotated by an air-operated motor-90 supported by theend plate 82. Theair motor 90 is connected by anair feed pipe 92 to a pipe union 93, see FIG. 4, mounted on thehousing 70 which also supports a manually operableair control tap 94 communicating with the union 93 and with a pressureair feed pipe 96 connected to theair compressor 159 as indicated.

Mounted on thehousing 70 is anelectric switch 97 by which theelectrostatic generator 22 can be readily connected to and disconnected from the mains supply and also a furtherelectric switch 99 by which theelec tric motor 32 can be switched on and off and it will be appreciated that thecontrol tap 94 andelectric switches 97 and 99 are all conveniently placed for manual operation by a person holding thesocket handle 64 which is shown for convenience only as resting on the top of theframe 11. If theair compressor 159 is electrically driven a further switch, not shown, may be mounted on the housing to start and stop the compressor.

Thefeed tube 74 of thesubsidiary discharge head 75, see FIG. 5, enters thecylindrical wall 79 at an end portion thereof remote from theelectrode 84 and disposed between said feed tube and electrode is atransverse baffle plate 98, which is of substantially semi-circular formation and extends between thewall 79 and the exterior of theair motor 90 which, in addition to having an air inlet in communication with theair feed pipe 92, preferably also has an air exhaust, not shown, externally of thehead 75.

Formed in thecylindrical wall 79 at a diametrically opposite position to thefeed tube 74 is a relief or bleedopening 100 across the entire area of which extends aperforated support grid 102 lined with aporous liner 104 which may be made of expanded polystyrene,

In order to apply a coating of particle material to a substrate wall or ceiling, after thefeed tube 74 has been inserted into thesocket handle 64 and theclamping screw 72 has been tightened onto the feed tube and the substrate surface has had a suitable adhesive applied thereto, the operator grips thesocket handle 64 and suitably orientates the portablesubsidiary discharge head 75 so that the subsidiary discharge head opening 83 thereof, across which theelectrode 84 extends, is directed to said adhesively coated substrate surface and the two manuallyoperable switches 97 and 99 are operated to charge theelectrodes 18 and 84 and to start theelectric motor 32. Theair compressor 159 is also started in a manner dependent upon whether this is an electrically or, for example, an internal combustion engine driven air compressor and thecontrol tap 94 is manually opened whereby theair motor 90 is caused to rotate theagitating brush 86.

The opening orport 44 is manually opened by operation of theslide 46 and particle material in thecontainer 14 is supplied in a constant regulated manner to said opening or port by themeasuring chambers 42 of the agitating andmetering device 35 which is rotated at a constant selected speed by theelectric motor 32 and which speed is found to be suitable for the particular particle material being used. Resulting from the action of theinjector device 50, a stream of particle material which has been electrostatically charged by theelectrode 18 is fed through thepipe 60,hose 63 andextension 65 into the portablesubsidiary discharge head 75 and the material passes past theagitating brush 86 and through theelectrode 84 and subsidiary discharge opening 83 and thence onto the adhesively coated substrate surface. Surplus air passes through theopening 100 and is filtered by theliner 104 so that particle material does not pass through said opening.

Whilst thesubsidiary discharge head 75 is satisfactory for coating the major parts of a wall or ceiling surface, it is not ideally suitable for coating the surfaces forming an inside corner and for this purpose a portablesubsidiary discharge head 106, illustrated in FIG. 6, is employed. Thissubsidiary discharge head 106 comprises a circular feed pipe orconnection part 108 which is adapted to be inserted into thesocket handle 64 against thestop shoulder 76 and is secured by theclamping screw 72. Thesubsidiary discharge head 106 is provided at its end opposite thefeed tube 108 with a flattened fishtail formation 107 (illustrated in end elevation in FIG. 9) affording an elongatedrectangular discharge opening 109. It follows, therefore, that the length of the opening is considerably greater than the width of the opening which is slightly smaller than the upright external width of the fishtail formation shown in FIG. 6. Theflattened fishtail formation 107 is capable of being inserted into inside corner formations to apply a particle material coating to the substrate surface or surfaces to completely cover said surface or surfaces.

The subsidiary head discharge opening 109 is not provided with an electrode and it is found that as the particle material is initially charged by theelectrode 18, it is sufficiently recharged or boosted by the electrostatically charged connecting ring orelectrode 66 through which the particle material passes before being discharged through theopening 109.

The strength or intensity of the suction effect developed by theinjector device 50 can be varied by altering the width of thegap 50 by adjustment of theoutlet pipe 55 relative to thenozzle 51 so that the rate of flow of the stream of air and particle material through theoutlet pipe 55 can be adjusted to suit requirements. Furthermore, the supply of particle material to theport 44 and thus to theinjector device 50 is controlled by the power driven agitating andmetering device 35 so that an accurately regulated supply of particle material is provided for theinjector device 50 and thus to the portable subsidiary discharge heads or 106. Alternatively, when thedischarge head 28 is being used and the opening orport 44 has been closed by theslide 46, the particle material is fed from thechambers 42 downwardly through theelectrode 18 and main discharge head opening 31 at an accurately regulated uniform rate dependent partially upon the selected speed of rotation of the agitating andmetering device 35.

Thus, the agitating andmetering device 35 is employed when any one of the threedischarge heads 28, 75 and 106 is used and ensures that an accurately controlled uniform rate of discharge of the particle material issues from the particular discharge head whereby a uniform coating of particle materials is applied to the substrate surface.

The distance of the adjusting ormetering device 35 from theelectrode 18 and of thebrush 86 from theelectrode 84 can be adjusted in any convenient manner to exercise a measure of control of discharge of the particle material from theheads 28 and 75 respectively and for this purpose the speed of rotation of saiddevice 35 andbrush 86 can also be adjusted.

Whilst the apparatus illustrated in the drawings is specifically intended for use with particle material in the form of fibres of such a length as to enable a pile carpet coating to be applied to a substrate surface and which fibres may be made of nylon or other suitable plastics or other material, it should be appreciated that the apparatus is also suitable for particle materials of other than fibrous formation. When fibres are employed, however, the effect of electrostatically charging the fibres is that during their movement from theappropriate discharge head 28, 75 or 106 they are caused to assume a parallel orientation and are aligned in the direction between the discharge head and the substrate surface and their velocity is such that their ends adjacent said surface penetrate the settable adhesive coating to a sufficient depth that the fibres are embedded in the adhesive coating and afford mutual support for each other and provide an upstanding pile on said substrate surface.

What is claimed is:

1. Apparatus for electrostatically applying a coating of a particle material to a substrate to which a settable adhesive has been applied, the apparatus comprising a container for a stock of particle material; a single metering means comprising a chamber supplied with particle material from the container and comprising a base and an upstanding peripheral wall, and a power rotatable paddle wheel having blades which are adapted to sweep the volume of the chamber on rotation of the paddle wheel and between adjacent blades there being defined compartments, each adapted to contain a pre determined amount of particle material, the paddle wheel having an axis of rotation which is disposed vertically, said chamber having two alternatively openable exits, one exit being disposed in the base and the other exit being disposed in said upstanding peripheral wall, a manually portable discharge head being provided in communication with said other exit, and said one exit constituting a downwardly directed discharge head; said single metering means serving to meter the amount of particle material supplied to the discharge heads; the apparatus further including an electrostatic generator; main electrode means electrically connected to said generator and disposed in said chamber to electrically charge the particle material therein; and subsidiary electrode means electrically connected to said generator and associated with said portable discharge head.

2. Apparatus according toclaim 1 wherein the main electrode means comprises a grid extending across said one exit.

3. Apparatus according toclaim 1 and including a wheeled framework adapted to be movable over a horizontal floor surface, said downwardly directed discharge head being spaced above the level of the floor engaging wheels.

4. Apparatus according toclaim 1 wherein a tubular connecting passage having a flexible part is provided in communication with said other exit and a pressure gas inlet is associated with the passage to provide a flow of gas under pressure to carry the particle material towards the manually portable discharge head when the pressure gas supply is operative.

5. Apparatus according toclaim 1 wherein an agitating means is provided in the portable discharge head adjacent the subsidiary electrode means and power driving means are drivingly connected to the agitating means to operate same.

6. Apparatus according to claim 5 wherein the manually portable discharge head includes a relief opening having a porous covering, and a discharge opening spaced from said relief opening, the porous liner enabling surplus pressure gas to escape therethrough but preventing escape of particle material through the relief opening, and the agitating means and subsidiary electrode means being disposed in the path of the partis Luau-m twat: Qua, r

Claims (6)

1. Apparatus for electrostatically applying a coating of a particle material to a substrate to which a settable adhesive has been applied, the apparatus comprising a container for a stock of particle material; a single metering means comprising a chamber supplied with particle material from the container and comprising a base and an upstanding peripheral wall, and a power rotatable paddle wheel having blades which are adapted to sweep the volume of the chamber on rotation of the paddle wheel and between adjacent blades there being defined compartments, each adapted to contain a predetermined amount of particle material, the paddle wheel having an axis of rotation which is disposed vertically, said chamber having two alternatively openable exits, one exit being disposed in the base and the other exit being disposed in said upstanding peripheral wall, a manually portable discharge head being provided in communication with said other exit, and said one exit constituting a downwardly directed discharge head; said single metering means serving to meter the amount of particle material supplied to the discharge heads; the apparatus further including an electrostatic generator; main electrode means electrically connected to said generator and disposed in said chamber to electrically charge the particle material therein; and subsidiary electrode means electrically connected to said generator and associated with said portable discharge head.

2. Apparatus according to claim 1 wherein the main electrode means comprises a grid extending across said one exit.

3. Apparatus according to claim 1 and including a wheeled framework adapted to be movable over a horizontal floor surface, said downwardly directed discharge head being spaced above the level of the floor engaging wheels.

4. Apparatus according to claim 1 wherein a tubular connecting passage having a flexible part is provided in communication with said other exit and a pressure gas inlet is associated with the passage to provide a flow of gas under pressure to carry the particle material towards the manually portable discharge head when the pressure gas supply is operative.

5. Apparatus according to claim 1 wherein an agitating means is provided in the portable discharge head adjacent the subsidiary electrode means and power driving means are drivingly connected to the agitating means to operate same.

6. Apparatus according to claim 5 wherein the manually portable discharge head includes a relief opening having a porous covering, and a discharge opening spaced from said relief opening, the porous liner enabling surplus pressure gas to escape therethrough but preventing escape of particle material through the relief opening, and the agitating means and subsidiary electrode means being disposed in the path of the particle material as it passes to said discharge opening.

Images