FR2868708A3 - SPRAY GUN - Google Patents

Abstract

A paint gun has a spray port cap (4) disposed in front of a nozzle (23) of a gun body (2), and formed with a central spray port (42), a set of forming holes. mist (43), a set of mist regulation holes (47), and a pair of horn protrusions (44). Each horn projection (44) is formed with an air passage (446), which terminates in first and second outlet openings (45, 46) which are oriented in different directions relative to the central orifice spray (42). Pressurized air flowing through the nozzle (23) exits the spray port cap (4) at the mist forming holes (43), mist control holes (47), and of the first and second outlet openings (45, 46) in the horn projections (44).

Description

SPRAY GUN

  The present invention relates to a spray gun, more particularly a spray gun that can improve the efficiency of a spray painting operation.

  A conventional spray gun includes a gun body, an operating unit, and a spray port cap.

  The gun body includes a handle portion, a head portion connected to the handle portion, and a nozzle mounted on one end of the head portion. The nozzle is formed with a nozzle orifice. The head portion is formed with a material passageway that is in fluid communication with the nozzle orifice and provides a path for the flow of paint from a paint reservoir to the nozzle orifice. The nozzle is further formed with a first air passage which is fluidly isolated from the nozzle orifice. The gun body is further formed with a second air passage extending from the handle portion and along the head portion, which is in fluid communication with the first air passage, and provides a path for the flow of pressurized air from a source of compressed air to the first air passage.

  The operating unit is mounted on the gun body, and includes a material flow control valve for controlling the flow of paint through the nozzle orifice, a flow control valve, and a flow control valve. air for regulating the flow of pressurized air through the second air passage, a trigger operably coupled to and controlling the opening and closing actions of the material flow control valve and the airflow regulating valve, and an airflow regulator for regulating the flow of air through the second air passage.

  The spray orifice cap includes a cap body. The cap body is disposed in front of the nozzle, and has a central spray port, two pairs of mist-forming holes, and a pair of horn protrusions. The central spray orifice has an orifice axis extending in a longitudinal direction, and is in fluid communication with the nozzle orifice. The mist forming holes in each pair are opposed to each other in a direction diametrical with respect to the orifice axis, and are disposed on opposite sides of the central spray orifice. The horn projections extend from the cap body in the longitudinal direction away from the nozzle, and are disposed adjacent to the mist forming holes. Each horn projection has a third air passage. The third air passage terminates in an outlet opening which is formed in a lateral side, which is oriented towards the central spray orifice, of the corresponding horn protrusion. The mist forming holes and the third air passages are in fluid communication with the first air passage.

  When the expansion of the operating unit is actuated to open the air flow control valve, pressurized air from the compressed air source flows through the second flow passage. air, the first air passage, and exit through the mist forming holes and the outlet openings, which creates a negative air pressure around the central spray orifice. Since actuation of the trigger also causes the material flow control valve to open, the paint is drawn from the paint tank through the material passageway and out through the orifice. central atomizer, where it will be sprayed by the flow of pressurized air coming out through the mist forming holes and the outlet openings so that the paint can be sprayed on a target surface.

  However, because of the high speed of the pressurized air flow, some of the spray paint may bounce off the target surface, polluting the work environment and causing paint loss.

  On the basis of actual tests using a conventional spray gun, when the airflow pressure in the vicinity of the central spray orifice is 1.86 to 2.76 bar (27 to 40 psi), only 35 40% of the spray paint adheres to the target surface to form an effectively painted area. The remainder of the spray paint is either dispersed in the ambient air or spread on the target surface within a dispersion distance from the actually painted area to form a painted painted area. ineffective.

  On the other hand, when the pressure of the air flow in the vicinity of the central spray orifice is reduced to a level below 0.7 bar (10 psi), for example by operating the air flow regulator or using a high-volume, low-pressure spray gun, up to 60 of the spray paint adheres to the target surface to form the effectively painted area, and the amount of spray paint that disperses into ambient air or forms the inefficiently painted area is reduced accordingly. However, due to the reduction of the airflow pressure, the efficiency of the spray is reduced so that the painted area has a coarse surface and lacks luster.

  Therefore, the object of the present invention is to provide a spray gun that can avoid the aforementioned drawbacks that are associated with the prior art.

  Therefore, a spray gun according to the present invention comprises a gun body, an operating unit, and a spray port cap.

  The gun body includes a handle portion, a head portion connected to the handle portion, and a nozzle mounted on the head portion. The nozzle is formed with a nozzle orifice. The gun body is formed with a material passageway that is in fluid communication with the nozzle orifice and provides a path for the flow of paint to the nozzle orifice. The nozzle is further formed with a first air passage which is fluidly isolated from the nozzle orifice. The gun body is further formed with a second air passage that is in fluid communication with the first air passage and provides a path for the flow of pressurized air from an air source. compressed until the first air passage.

  The operating unit is mounted on the gun body, and includes a material flow control valve for controlling the flow of paint through the nozzle orifice, a flow control valve, and a flow control valve. air for regulating the flow of pressurized air through the second air passage, and an expansion operatively coupled to and controlling the opening and closing actions of the flow control valve of the material and the regulating valve of the air flow.

  The spray orifice cap includes a cap body. The cap body is disposed in front of the nozzle, and is formed with a central spray orifice, at least one pair of mist forming holes, and a pair of horn protrusions, and at least one pair of mist control holes. . The central spray orifice has an orifice axis extending in a longitudinal direction, and is in fluid communication with the nozzle orifice. The mist forming holes are opposed to each other in a first direction diametrical with respect to the orifice axis, and are disposed on opposite sides of the central spray orifice. The horn projections extend from the cap body in the longitudinal direction away from the nozzle, and are disposed adjacent to the mist forming holes.

  Each of the horn protrusions has a root end which is connected to the cap body, a tip end which is opposed to the root end in the longitudinal direction, and a lateral side which extends between the root ends and the root end. end and which is oriented towards the central spray orifice. Each of the horn projections is formed with a third air passage. The third air passage terminates in at least a first outlet opening that is formed in the lateral side, and a second outlet opening that is formed in the end end. The mist control holes are opposed to each other in a second direction diametrical with respect to the orifice axis, and are disposed on opposite sides of the central spray orifice. The second diametrical direction forms an angle with the first diametrical direction. The mist forming holes, the third air passages in the horn projections, and the mist regulating holes are in fluid communication with the first air passage.

  Other features and advantages of the present invention will become more apparent upon reading the following detailed description of the preferred embodiment with reference to the accompanying drawings, in which: Figure 1 is a schematic sectional view of the embodiment preferred a spray gun according to the present invention; Figure 2 is a perspective view of a spray port cap of the preferred embodiment; and Figures 3 and 4 show the result of a spraying operation performed using the spray gun of the preferred embodiment.

  Referring to Figs. 1 and 2, the preferred embodiment of a spray gun according to the present invention is shown and comprises a gun body 2, an operating unit 3, and a spray port cap 4.

  The gun body 2 comprises a handle portion 21, a head portion 22 connected to the handle portion 21, and a nozzle 23 mounted on the head portion 22. The nozzle 23 is formed with a nozzle orifice 24. The The head portion 22 is formed with a material passage 25 which is in fluid communication with the nozzle orifice 24 and which provides a path for the flow of paint from a paint reservoir (not shown) to the nozzle orifice 24. The nozzle 23 is furthermore formed with a first air passage 26 which is fluidly isolated from the nozzle orifice 24. The gun body 2 is furthermore formed with a second passage of FIG. air 27 extending from the handle portion 21 and along the head portion 22, which is in fluid communication with the first air passage 26, and which provides a path for the air flow under pressure from a source of compressed air (no shown) to the first air passage 26.

  The operating unit 3 is mounted on the gun body 2, and comprises a material flow control valve 31 for regulating the flow of paint through the nozzle orifice 24, a control valve of the air flow 33 for regulating the flow of pressurized air through the second air passage 27, a trigger 32 operably coupled to and controlling the opening and closing actions of the material flow control 31 and air flow control valve 33, and an air flow regulator 34 for regulating air flow through the second air passage 27.

  Since the feature of the present invention does not lie in the specific configurations of the gun body 2 and the operating unit 3, which are similar to those of the conventional spray gun, they will not be described in more detail. in this document for the sake of brevity.

  The spray orifice cap 4 comprises a cap body 41. The cap body 41 is disposed in front of the nozzle 23, and is formed with a central spray orifice 42, at least one pair of mist forming holes 43, a pair of horn protrusions 44, and at least one pair of mist control holes 47. The central spray port 42 has an orifice axis (z) extending in a longitudinal direction, and is matched and in fluidic communication with the nozzle orifice 24. In this embodiment, there are two pairs of mist forming holes 43. The mist forming holes 43 in each pair are opposed to each other in a first diametrical direction (ri) with respect to the orifice axis (z), and are disposed on opposite sides of the central spray orifice 42. The horn projections 44 extend from the cap body 41 into the longitudinal direction away from the nozzle 23, and are disposed adjacent to the mist forming holes 43. Each of the horn projections 44 has a root end 440 which is connected to the cap body 41, an end end 442 which is opposite the root end 440 in the longitudinal direction, and a lateral side 444 which extends between the root and tip ends 440, 442 and is oriented towards the central spray port 42. Each of the horn projections 44 is formed with a third passage of The third air passage 446 terminates in a first exit opening 45 which is formed in the lateral side 444, and a second exit opening 46 which is formed in the end end 442. In this mode In one embodiment, the lateral side 444 is formed with a pair of first outlet openings 45. The mist control holes 47 are opposed to each other in a second diametrical direction (r2) with respect to the center line. ' orifice (z), and are arranged on the opposite sides of the central spray orifice 42. The second diametrical direction (r2) forms an angle with the first diametrical direction (ri). In this embodiment, the second diametrical direction (r2) is transverse to the first diametrical direction (ri). The mist forming holes 43, the third air passages 446 in the horn protrusions 44, and the mist regulating holes 47 are in fluid communication with the first air passage 26. The spray port cap 4 further comprises a locking ring 48 which removably surrounds and locks the cap body 41 on the head portion 22 of the gun body 2.

  When the trigger 32 of the operating unit 3 is actuated to open the air flow control valve 33, pressurized air from the source of compressed air (not shown) flows through the second air passage 27, the first air passage 26, and exits through the mist forming holes 43, the first and the second outlet openings 45, 46, and the mist control holes. 47. Since a negative air pressure is created around the central spray port 42, and since the operation of the trigger 32 also causes the material flow control valve to open 31, the paint is extracted from the paint tank (not shown) through the material passage 25, and out through the central spray port 42, where it will be sprayed by the pressurized air stream which exits through the nozzle 23 of such that the paint can be sprayed on a target surface.

  Referring to Figures 3 and 4, the pressurized air flowing through the second outlet openings 46 and the mist control holes 47 serves primarily to form an air barrier (H) around the spray paint . As a result, the dispersion of the spray paint in the ambient air can be reduced, thereby enlarging the effectively painted area (A). The pressurized air flowing through the second outlet openings 46 and the mist control holes 47 controls the width and length of the effectively painted area (A). As such, the inefficiently painted area (B) within a dispersion distance (D) from the effectively painted area (A) is reduced accordingly. In consideration of the configuration mentioned above, when the pressure of the air flow in the vicinity of the central spray orifice 42 is increased to improve the spray efficiency, due to the corresponding increase in air pressure through the second exit openings 46 and the mist control holes 47, a reinforced air barrier (H) will be formed to minimize dispersion of the spray paint. As a result, pollution of the work environment and paint losses can be reduced when the paint spray gun of the present invention is used.

Claims (3)

  A spray gun characterized by comprising: a gun body (2) having a handle portion (21), a head portion (22) connected to the handle portion (21), and a nozzle ( 23) mounted on the head portion (21) and having a nozzle orifice (24), the gun body (2) being formed with a material passage (25) which is in fluid communication with the nozzle orifice ( 24) and which provides a path for the flow of paint to the nozzle orifice (24), the nozzle (23) further comprising a first air passage (26) which is fluidly isolated from the orifice nozzle (24), the gun body (2) being further formed with a second air passage (27) which is in fluid communication with the first air passage (26) and which provides a path for the flow of pressurized air from a source of compressed air to the first air passage (26), an operating unit (3) mounted on the the gun body (2) and comprising a material flow control valve (31) for regulating the flow of paint through the nozzle orifice (24), a flow control valve air (33) for regulating the flow of pressurized air through the second air passage (27), and a trigger (32) operably coupled to and controlling the opening and closing actions of the material flow control valve (31) and the air flow control valve (33), and a spray port cap (4) comprising a cap body (41) disposed in front of the nozzle (23) and formed with a central spray orifice (42) which has an orifice axis (z) extending in a longitudinal direction and which matches and is in fluid communication with the nozzle orifice ( 24), at least one pair of mist forming holes (43) which are opposed to each other in a diametral direction (ri) relative to the orifice axis (z) and which are disposed on opposite sides of the central spray orifice (42), and a pair of horn protrusions (44) which extend from the cap body (41) in the longitudinal direction away from the nozzle (23) and which are disposed adjacent to the mist forming holes (43), each of the horn projections (44) having one end a root end (440) which is connected to the cap body (41), a tip end (442) opposite to the root end (440) in the longitudinal direction, and a lateral side (444) which extends between the root and tip ends (440, 442) and which is directed toward the central spray orifice (42), each of the horn projections (44) having a third air passage (446), the third an air passage (446) terminating in at least a first exit opening (45) which is formed in the lateral side (444), the mist forming holes (43) and the third air passages (446) in the horn projections (44) being in fluid communication with the first air passage (26), characterized in that: the third air passage (446) is further terminated by a second outlet opening (46) which is formed in the tip end (442), the cap body (41) having at least a pair of mist regulating holes (47) which are opposed to each other in a second diametrical direction (r2) with respect to the orifice axis (z) and which are disposed on opposite sides of the central spray orifice (42), the second diametrical direction (r2) forming an angle with the first diametral direction (rl), the mist regulating holes (47) being in fluid communication with the first air passage ( 26).   2. Spray gun according to claim 1, further characterized in that the second diametral direction (r2) is transverse to the first diametric direction (ri).   A spray gun according to claim 1, characterized in that the spray orifice cap (4) further comprises a locking ring (48) which removably surrounds and locks the cap body (41) on the head portion (22) of the gun body (2).