GB2129711A - Airless spray coating - Google Patents

Airless spray coating Download PDF

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Publication number
GB2129711A
GB2129711A GB08323543A GB8323543A GB2129711A GB 2129711 A GB2129711 A GB 2129711A GB 08323543 A GB08323543 A GB 08323543A GB 8323543 A GB8323543 A GB 8323543A GB 2129711 A GB2129711 A GB 2129711A
Authority
GB
United Kingdom
Prior art keywords
coating material
air
coating
stream
spout
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Withdrawn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
GB08323543A
Other versions
GB8323543D0 (en
Inventor
Hara Masumi
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.)
Asahi Okuma Industrial Co Ltd
Original Assignee
Asahi Okuma Industrial Co Ltd
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 Asahi Okuma Industrial Co Ltd filed Critical Asahi Okuma Industrial Co Ltd
Publication of GB8323543D0 publication Critical patent/GB8323543D0/en
Publication of GB2129711A publication Critical patent/GB2129711A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D1/00—Processes for applying liquids or other fluent materials
    • B05D1/02—Processes for applying liquids or other fluent materials performed by spraying
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B1/00—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means
    • B05B1/02—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to produce a jet, spray, or other discharge of particular shape or nature, e.g. in single drops, or having an outlet of particular shape
    • B05B1/04—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to produce a jet, spray, or other discharge of particular shape or nature, e.g. in single drops, or having an outlet of particular shape in flat form, e.g. fan-like, sheet-like
    • B05B1/042—Outlets having two planes of symmetry perpendicular to each other, one of them defining the plane of the jet
    • 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
    • B05B7/08—Spray pistols; Apparatus for discharge with separate outlet orifices, e.g. to form parallel jets, i.e. the axis of the jets being parallel, to form intersecting jets, i.e. the axis of the jets converging but not necessarily intersecting at a point
    • B05B7/0807—Spray pistols; Apparatus for discharge with separate outlet orifices, e.g. to form parallel jets, i.e. the axis of the jets being parallel, to form intersecting jets, i.e. the axis of the jets converging but not necessarily intersecting at a point to form intersecting jets
    • B05B7/0815—Spray pistols; Apparatus for discharge with separate outlet orifices, e.g. to form parallel jets, i.e. the axis of the jets being parallel, to form intersecting jets, i.e. the axis of the jets converging but not necessarily intersecting at a point to form intersecting jets with at least one gas jet intersecting a jet constituted by a liquid or a mixture containing a liquid for controlling the shape of the latter
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B9/00—Spraying apparatus for discharge of liquids or other fluent material, without essentially mixing with gas or vapour

Abstract

In a method of airless spray coating, air streams blow against both side edges of a stream of coating material in the form of flat segment, so that the air streams lie in the same plane as that defined by the coating material. A spray-gun has air outlets 20 on both longitudinal sides of a slit-like spout 9 of coating material so that compressed air jetted through these air outlets 20 is directed the edges of a stream of the coating material. <IMAGE>

Description

SPECIFICATION Method of airless spray coating and spray-gun for airless coating Background of invention: The present invention relates to a method of airless spray coating by which an amount of liquid coating material is highly pressurized, jetted through a slit-like spout of coating material in a pattern of flat segment, atomized by collision with the ambient air and finally deposited on an object to be coated, and also to a spray-gun used to carry out this method.
Generally in the airless spray coating, an amount of coating material is sprayed in elongate crosssection and an object to be coated is moved transversely of a length of said cross-section relative to said cross-section so as to obtain desired coating along a band of constant width. To achieve this, a nozzle having a laterally elongate spout of coating material in the form of a lip or like has usually been incorporated into the spray-gun. With such nozzle, however, portions of the stream of coating material sprayed through the spout of coating material at the areas adjacent the longitudinally opposite ends must be sprayed at a velocity lower than the velocity at which the central portion is sprayed and poorly atomizeti even when come into collision with the ambient air.As a result, sub-streams b, b conventionally referred to as "tails" comprising relatively coarse particles are formed along both sides of the central main stream a properly atomized and, if these sub-streams b, bare deposited on the object to be coated, rough coating lines might be formed along both sides of a smooth band of coating formed by deposition of the main stream a. This is the reason for which the airless coating excellent in the efficiencies of deposition as well as operation has not necessarily been evaluated as a preferable method for the final coating.
A principal object of the present invention is to eliminate these drawbacks inherent in the airless spray coating of prior art and thereby to obtain a uniformly coated surface.
Summary of invention: The method of airless spray coating according to the present invention substantially comprising provision of air streams blowing against both side edges of a stream of coating material sprayed through a slit-like spout of coating material in a pattern of flat segment so that the air streams lie in the same plane as the plane defined by said stream of coating material.Blowing of the air streams serves to urge both side edges of the stream of coating material into the internal zone thereof and to stabilize a width of the spray pattern so as to provide uniform coating the spray-gun for airless coating according to the present invention substantially comprises provision of air outlets on both longitudinal sides of a slit-like spout of coating material so that compressed air jetted through these air outlets is directed to a stream of coating material sprayed through said slit-like spout of coating material. Said method according to the present invention is reliably executed by this spray-gun.
Brief description of drawing: Figure 1 is a sectional view illustrating a stream of coating material formed by the airless spray of prior art; and Figures 2 through 6show embodiments of a spray-gun according to the present invention, of which Figure 2 is a longitudinal section of a first embodiment; Figure 3 is an enlarged cross-section thereof; Figure 4 is a frontal view illustrating an important part thereof; Figure 5 is a longitudinal section of a second embodiment and Figure 6 is an enlarged frontal view illustrating an important part thereof.
Detailed description of embodiments: Now preferred embodiments of the airless coating spray-gun according to the present invention will be described in reference with Figures 2 through 6 with respect to construction as well as to manner of function and thereby the method of airless spray coating according to the present invention will be made comprehensible.
The first embodiment as shown by Figures 2 through 4 is the airless spray-gun for electrostatic coating comprising a gunbarrel 1 having an outlet channel 3 of small diameter extending through a front portion of the gunbarrel and a passage 2 of coating material communicating with said outlet channel 3. A valve rod 6 is inserted into the passage 2 of coating material and integrally provided at its front end with a spheric valve body 5 adapted to be engaged with and disengaged from a valve seat 4 so that the outlet channel is closed and opened. A nozzle holder 10 including a cylindrical spacer 7 and a nozzle tip 8 fitted thereinto is secured by a cap 12 to the front end of the gunbarrel 1 with interposition of a retainer 11 fitted around said nozzle holder 10.A ring 14 formed in its inner periphery with a groove 18 is mounted around said cap 12 and clamped buy a nut 15. An elbow 16 is threaded into said ring 14 until a channel longitudinally extending through said elbow opens into said groove 18. An air supplying pipe 17 communicating with a compressed air source not shown is connected to said elbow 16. The cap 12 is formed with a plurality of air vents 13 to establish a communication between an interior of the cap 12 and the groove 18 formed in the inner periphery of the ring 14.The retainer 11 is formed with a diametrically opposed pair of air passages 19 which are so inwardly inclined that their front ends as air outlets 20 open at opposite sides of a laterally elongated lip-shaped spout 9 of coating material, formed in a front end of a nozzle tip 8 and streams of compressed air supplied from the air supply pipe 17 are directed to a stream of coating material injected from said spout 9 of coating material along the opposite edges adjacent points of atomization.
A corona pin 21 extends through the nozzle holder 10 to electrostatically charge the stream of coating material injected from the spout 9 of coating material and connected via an electrically conductive packing 22, a conductor 23 and a high resistance 24 to a high voltage generator not shown.
A manner in which this embodiment functions will be now described. When the valve body 5 is disengaged from the valve seat 4 and thereby opens the outlet channel 3 as the valve rod 6 is retracted, an amount of coating liquid pressurized by a pump not shown at a pressure of 10 to 210 kg/cm2 flows through the passage 2 of coating material, the outlet channel 3 and the cavity within the spacer 7 into the nozzle tip 8, then injected through the spout 9 of coating material in form of segmental film as seen in the plan view as shown by Figure 3 and is finally atomized as a result of collision with the ambient air while properly oriented under effect of the electrostatic field generated by the corona pin 21.According to this embodiment of the present invention, the pressurized air is jetted through the pair of air outlets 20 and blow against the stream of coating material along the both side edges thereof immediately after this stream or coating material has been discharged through the spout 9 of coating material. Such air streams serves to urge sub-streams b comprising relatively coarse particles and produced along opposite sides of a main stream a properly atomized into the latter a and to agitate the stream of coating material as a whole so that the coarse particles may be spread among the fine particles. With this embodiment, thus, an amount of coating material is sprayed with a uniform particle size distribution and a width-constant pattern without a tail onto the object to be coated and thereby uniform coating film is obtained.
The air streams jetted the respective air outlets 20 at an excessively low pressure could not adequately urge the sub-streams b into the main stream a and the air streams at an excessively high pressure, on the contrary, would disturb the proper pattern of the main stream a. It has been experimentally found that a preferable pressure lies in a range of apporximately 0.2 to 0.5 kg/cm2. Moreover, these air streams are to be jetted in the same plane as the plane defined by the flat pattern of the stream of coating material, so that an order of 0.5 to 1.0 mm is sufficient for the diameter of each air outlet 20. In consequence, consumption of air is normally as small as aproximately 0.5 m3/h and a possible mixture of air into coating material is substantially negligible.
Figures 5 and 6 show a second embodiment of the spray-gun constructed in accordance with the present invention. In this embodiment, there are provided, with respect to a nozzle tip 30 having a vertically elongate spout 31 of coating material, a vertically and diametically opposed pair of air outlets 32 together with laterally opposed five pairs of air outlets 32. A stream of coating material sprayed through the spout 31 of coating material in form of segmental film which is flat in the vertical direction is enclosed by the air streams jetted through the respective air outlets 32 substantially in parallel to one another so that particles of coating material contained in the stream of coating material may be effectively prevented from scattering. Furthermore, there are provided a vertically and diametically opposed pair of air outlets 33 through which air streams blow against the stream of coating material perpendicularly to the axis thereof. Each of air supply pipes 34 serving to supply compressed air to the respective air outlets 33 is provided with a valve 35 to be adjustably opened so that an amount of air jetted through the associated air outlet 33 is adjustable and a degree to which the associated side edge of the stream of coating material is to be urged towards the axis of said stream is also adjustable to control a pattern width.

Claims (3)

1. A method of airless spray coating characterised by that there are provided air streams blowing against both side edges of a stream of coating material jetted through a slit-like spout of coating material in a pattern of flat segment so that the air streams lie in the same plane as the plane defined by said stream of coating material.
2. A method of airless spray coating according to Claim 1 wherein said air streams are jetted at a pressure of 0.2 to 0.5 kg/cm2.
3. A spray-gun for airless coating characterised by that there are provided air outlets on both longitudinal sides of a slit-like spout of coating material so that compressed air jetted through these air outlets is directed to a stream of coating material jetted through said slit-like spout of coating material.
GB08323543A 1982-09-03 1983-09-02 Airless spray coating Withdrawn GB2129711A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP15437382A JPS5946159A (en) 1982-09-03 1982-09-03 Airless spray painting method and gun therefor

Publications (2)

Publication Number Publication Date
GB8323543D0 GB8323543D0 (en) 1983-10-05
GB2129711A true GB2129711A (en) 1984-05-23

Family

ID=15582735

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08323543A Withdrawn GB2129711A (en) 1982-09-03 1983-09-02 Airless spray coating

Country Status (4)

Country Link
JP (1) JPS5946159A (en)
DE (1) DE3329880A1 (en)
FR (1) FR2532560B1 (en)
GB (1) GB2129711A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3238201A1 (en) * 1982-10-15 1984-06-20 Oskar Frech GmbH + Co, 7060 Schorndorf Spray head, in particular for applying and dispersing parting agent onto diecasting moulds and injection moulds
WO1996039258A1 (en) * 1995-06-05 1996-12-12 Spray-Air Canada Ltd. Agricultural sprayer having spray shaping nozzles connected to low pressure air supply

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4967956A (en) * 1987-07-31 1990-11-06 Glas-Craft, Inc. Multi-component spraying system
US4891249A (en) * 1987-05-26 1990-01-02 Acumeter Laboratories, Inc. Method of and apparatus for somewhat-to-highly viscous fluid spraying for fiber or filament generation, controlled droplet generation, and combinations of fiber and droplet generation, intermittent and continuous, and for air-controlling spray deposition
JPH01127079A (en) * 1987-11-11 1989-05-19 Iwata Tosouki Kogyo Kk Finish method for spraying high viscosity coating material
DE10261576B4 (en) 2002-12-23 2013-01-31 Wolfgang Klingel Device for coating a printed circuit board
DE102009013379A1 (en) 2009-03-09 2010-09-16 Wolfgang Klingel Device for coating a substrate
CN112896655A (en) * 2021-02-20 2021-06-04 烟台久和开源健康营养中心 Multilayer capsule dust removal device and using method thereof

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB520367A (en) * 1938-03-31 1940-04-22 Binks Mfg Co Air nozzle for flat spraying appliances
GB577357A (en) * 1942-10-31 1946-05-15 Eccoverken Ab Method of spray-coating surfaces and a spraying device for the purpose
GB636397A (en) * 1946-01-17 1950-04-26 Emil Heijnes Advokatbyra Spray gun
GB1390383A (en) * 1971-03-03 1975-04-09 Electrogasdynamics Pneumatically assisted hydraulic spray coating apparatus
GB1558955A (en) * 1977-03-10 1980-01-09 Skm Sa Hydrostatic print atomization spray-guns

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4829606B1 (en) * 1969-08-07 1973-09-12
NL178487C (en) * 1976-03-26 1986-04-01 Stamicarbon DEVICE AND METHOD FOR SPRAYING A LIQUID.
FR2350887A1 (en) * 1976-05-10 1977-12-09 Air Ind Electrostatic paint spray with fan shaped jet - has shape formed by upwards sloping flat side jets between electrodes
DE2705642A1 (en) * 1977-02-10 1978-08-17 Otto Schiemann Paint spray head jet width control system - has compressed air discharge holes on each side of slot for varying pressure
FR2382947A1 (en) * 1977-03-10 1978-10-06 Skm Sa HYDROSTATIC PAINT SPRAY SPRAY GUN
FR2384551A1 (en) * 1977-03-22 1978-10-20 Skm Sa PNEUMATIC LIQUID SPRAYING PROCESS
US4273293A (en) * 1978-12-20 1981-06-16 Nordson Corporation Nozzle assembly for electrostatic spray guns
DE2922115A1 (en) * 1979-05-31 1980-12-04 Collardin Gmbh Gerhard METHOD FOR PRODUCING CONVERSION LAYERS ON METAL SURFACES BY SPRAYING
DE2924174C2 (en) * 1979-06-15 1984-04-19 Heinrich Bühnen KG Maschinenfabrik, Im- und Export, 2800 Bremen Method and nozzle of a device for applying an adhesive to a substrate
DE2937507A1 (en) * 1979-09-17 1981-04-02 Peter de 2057 Reinbek La Motte Underwater paint application process - has paint ejected from container within jacket of air under pressure

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB520367A (en) * 1938-03-31 1940-04-22 Binks Mfg Co Air nozzle for flat spraying appliances
GB577357A (en) * 1942-10-31 1946-05-15 Eccoverken Ab Method of spray-coating surfaces and a spraying device for the purpose
GB636397A (en) * 1946-01-17 1950-04-26 Emil Heijnes Advokatbyra Spray gun
GB1390383A (en) * 1971-03-03 1975-04-09 Electrogasdynamics Pneumatically assisted hydraulic spray coating apparatus
GB1558955A (en) * 1977-03-10 1980-01-09 Skm Sa Hydrostatic print atomization spray-guns

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3238201A1 (en) * 1982-10-15 1984-06-20 Oskar Frech GmbH + Co, 7060 Schorndorf Spray head, in particular for applying and dispersing parting agent onto diecasting moulds and injection moulds
WO1996039258A1 (en) * 1995-06-05 1996-12-12 Spray-Air Canada Ltd. Agricultural sprayer having spray shaping nozzles connected to low pressure air supply
US5680993A (en) * 1995-06-05 1997-10-28 National Research Council Of Canada Liquid atomizing device with controlled atomization and spray dispersion

Also Published As

Publication number Publication date
JPS5946159A (en) 1984-03-15
FR2532560A1 (en) 1984-03-09
FR2532560B1 (en) 1987-05-15
GB8323543D0 (en) 1983-10-05
DE3329880A1 (en) 1984-03-08

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