Patent Grant
9849474
The inventions relate generally to material application devices that are used for spraying powder coating material onto a work piece or object. More particularly, the inventions relate to material application devices, for example powder spray guns, that can be configured to receive powder coating material in dense phase and dilute phase.
A material application device is used to apply powder coating material to an object, part or other work piece or surface. A material application device is also referred to herein as a spray gun. The powder coating material can be delivered from a powder pump to a spray gun in dilute phase or dense phase. Dilute phase refers to a powder flow or stream that is a lean mixture, or in other words has a high ratio of flow air to powder. Dilute phase powder pumps are most commonly used in the form of a Venturi style pump that uses a large volume of air to draw powder from a supply and push the powder to the spray gun. Dense phase refers to a powder stream that is a rich mixture, or in other words has a low ratio of flow air to powder. Dense phase pumps are commonly used in the form of a pump chamber that uses pressure to fill and empty a pump chamber but with a low flow air volume, referred to hereinafter as flow air. Because dense phase systems use less flow air, the powder hoses can be made smaller in diameter compared with powder hoses used with dilute phase systems.
In an embodiment of the disclosure, a spray gun is presented that can be selectively configured to operate with a dilute phase powder delivery or a dense phase powder delivery. For example, the spray gun can be selectively configured to receive powder coating material from a Venturi powder pump or a dense phase powder pump.
In another embodiment presented herein, a configurable spray gun may include a gun body comprising a selectable forward section and a rearward section. The rearward section may be connected with either of two selectable forward sections so as to configure the spray gun to operate either with a dense phase powder supply or a with dilute phase powder supply. In another embodiment, the rearward section may include a selectable powder flow path that is connectable at an inlet end to a source of dense phase powder and at an outlet end to a selectable spray nozzle in the selectable forward section that may optionally include a diffuser. In still a further embodiment, an adapter assembly may be used to connect the rearward section with the selectable spray nozzle having an optional diffuser.
The disclosure also presents the concept of a spray gun that can be selectively configured, converted or re-configured to operate from a dilute phase powder pump or a dense phase powder pump as the case may be, while using many common components in the selectable configurations, for example, the same rearward section. Additional embodiments are disclosed herein.
In another embodiment, an adapter assembly provides an interface or connection between one of the selectable powder flow paths and a selectable spray nozzle. For example, the adapter assembly may provide an interface or connection between a reduced diameter selectable powder tube and a selectable spray nozzle. The reduced diameter selectable powder tube may be inserted through the rearward section by sliding the reduced diameter powder tube through a larger diameter selectable powder tube that is provided with the rearward section when the spray gun is to be assembled with a different selectable configuration. For example, the reduced diameter powder tube may be of a size that is useful with dense phase powder delivery from a dense phase pump, while the larger diameter powder may be of a size that is useful with a dilute phase pump, such as a Venturi pump to name one example. In another embodiment, the adapter assembly may provide continuity for an electrode.
In another embodiment, a spray gun that can be selectively configured to operate with a Venturi pump or a dense phase powder pump includes a gun body comprising a selectable forward section and a rearward section, with the selectable forward section including a selectable spray nozzle, an optional member for adding air to the powder flow, and an optional electrode. The rearward section may be used to support a selectable powder flow path, so that the rearward section is joinable with either of two selectable forward sections so as to form either of two selectable spray gun configurations.
In another embodiment, a first selectable spray gun configuration may include a first selectable spray nozzle and a first selectable powder flow path, with the first selectable powder flow path comprising a first cross-sectional area. A second selectable spray gun configuration may include a second selectable spray nozzle and a second selectable powder flow path, with the second selectable powder flow path comprising a second cross-sectional area, with the first cross-sectional area being different from said second cross-sectional area. In another embodiment, the second cross-sectional area is smaller than the first cross-sectional area.
In another embodiment, a spray gun that can be selectively configured to operate with a Venturi pump or a dense phase powder pump includes a gun body comprising a selectable forward section and a rearward section, with the selectable forward section further including two selectable configurations, for example, a spray nozzle or an air cap. Therefore, the spray gun may have three selectable configurations, for example, a dilute phase delivery spray gun, a dense phase delivery spray with a spray nozzle and a dense phase delivery spray gun with an air cap.
Another benefit of the selectively configurable spray gun concept is that for the second spray gun configuration, it will be noted that the second selectable flow path includes a second powder tube and an adapter tube which is part of an adapter assembly. This allows the adapter tube material to be selected based on the type of powder coating material being delivered through the second powder tube and sprayed through a spray nozzle, be it organic powder or porcelain enamel powder or other powder material. The powder flow does not impact surfaces as would occur when a spider is used, so the adapter support housing 106 will not exhibit wear.
In another embodiment, a spray gun includes a gun housing having a forward section and a rearward section, the forward section comprising a spray nozzle; the spray nozzle comprising an air diffuser for adding air to powder coating material when powder coating material is flowing through the spray nozzle, and a powder flow path extending through the spray gun from the rearward section to the forward section. The powder flow path comprises a first powder tube that extends through the rearward section and that is adapted to receive powder from a dense phase pump, and the rearward section includes a second powder tube of larger cross-sectional area than the first powder tube, the first powder tube extending through said second powder tube.
In all the embodiments, the spray guns may optionally have a bar mount configuration or a tube mount configuration. The spray guns also optionally may have a manual configuration or an automatic configuration. The spray guns may also optionally provide a charging electrode that is connectable to a high voltage source for applying electrostatic charge to the powder coating material during a coating operation.
These and other aspects and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description of the exemplary embodiments in view of the accompanying drawings.
Although the inventions are described in terms of exemplary embodiments of spray guns with specific configurations, those skilled in the art will readily appreciate that the inventions will find application and use with many different types of spray gun designs. For example, automatic sprays guns may have mounting configurations other than bar mount or tube mount, and manual guns can have many different configurations. An automatic spray gun is one that is typically mounted on a support structure that can move the spray gun into position for a coating operation, with the spray gun actuation (for example, trigger on and off times for controlling spraying) being controlled electronically. A manual spray gun has a handle and is usually manually gripped by the operator and triggered manually to start and stop a coating operation. The exemplary embodiments also use an electrode that is connectable to a high voltage supply, for example a multiplier, so as to apply electrostatic charge to the powder coating material, but the inventions also may be used with spray guns that are not corona discharge type electrostatic spray guns. For example, the inventions may be used with tribo-charging electrostatic spray guns or non-electrostatic spray guns. Specific embodiments of various components used with the spray gun are exemplary and may be changed depending on the particular spray gun design.
A powder coating operation or coating operation for short as used herein refers to the common method of using a powder spray gun to produce a cloud of powder coating material that is directed at an object being coated. Powder coating operations may be electrostatic or non-electrostatic as is well known.
Those skilled in the art will appreciate that powder flow passages, such as provided by powder tubes, are typically cylindrical in shape, but that non-cylindrical conduits may alternatively be used. Such powder tubes have an internal cross-sectional area but not necessarily an inside diameter. For the cylinder shaped powder tubes, the diameter is an adequate reference for comparing powder tubes of different size or different cross-sectional areas. Therefore, although in the disclosure herein we generally refer to diameter of exemplary powder tubes, we do not exclude from the scope of the inventions the alternative use of non-tubular powder conduits.
Although the exemplary embodiments are described in terms of use with dilute phase delivery system, such as for example, using a Venturi pump that produces a dilute phase powder flow input to a spray gun, and a dense phase delivery system, such as for example, using a dense phase pump that produces a dense phase powder flow input to a spray gun, such terminology should not be construed as limiting the use and scope of the inventions. Precise definitions of dilute phase and dense phase are not critical to the present inventions because the inventions allow for spray guns that can operate with dilute phase powder flow, dense phase powder flow or powder flow densities across a continuum of air/powder ratios in between dense phase and dilute phase. But for description purposes, a dilute phase powder flow is the type of powder flow that is produced by a dilute phase delivery system, for example a Venturi style powder pump, in which the powder flow has a leaner mixture of powder to air due to the high volume or amount of flow air (when compared with a dense phase powder pump) that is generated by the Venturi pump. A dense phase powder flow is the type of powder flow that is produced by a dense phase delivery system, for example a dense phase pump in which the powder flow has a richer mixture of powder to air due to the low volume or amount of flow air (when compared with a Venturi pump) that is generated by the dense phase pump. Dense phase pumps have smaller diameter powder hoses that provide dense phase powder flow to the spray gun as compared to the powder hoses that provide dilute phase powder flow from Venturi pumps due to the use of less flow air. For the basic concepts and embodiments herein, a dense phase powder flow is a powder flow produced by a dense phase pump that has a richer mixture of powder to air as compared to a dilute phase powder flow produced by a Venturi pump. The term “delivery system” is used interchangeably with the terms powder supply and powder pump.
By way of introduction, the present disclosure illustrates and describes a number of inventions and inventive concepts as embodied in the examples illustrated in the drawings and explained in the specification. One such inventive concept contemplates a first selectable spray gun configuration for powder delivered to the spray gun in dilute phase, and a second selectable spray gun configuration for powder delivered to the spray gun in dense phase.
In another embodiment, a spray gun can be selectively configured, converted or re-configured to operate from a dilute phase powder pump or a dense phase powder pump as the case may be, while using many common components in the two configurations, for example, the same rearward section. Additional embodiments are disclosed herein.
In a further embodiment of this concept, a spray gun with a first selectable configuration has a first selectable forward section that may be used to spray a lean mixture powder flow that is delivered from a dilute phase pump, for example a Venturi style pump. The dilute phase powder is input or supplied to a rearward section of the spray gun. The spray gun may then optionally be configured with a second selectable spray gun configuration in which a second selectable forward section may be used to spray a lean mixture powder flow, with the spray gun being supplied with powder coating material as a dense or rich mixture powder flow from a dense phase pump to the rearward section of the spray gun. Additional embodiments of this concept are presented herein.
The spray gun in the dense phase pump configuration or second selectable configuration provides a second selectable forward section that can be joined to the rearward section. The selectable forward section may include a second selectable spray nozzle and an adapter assembly that facilitates connecting or interfacing the second selectable spray nozzle to a forward portion or end of the rearward section. A second selectable powder flow path may be used that is connectable at an inlet end to a dense phase powder supply, and at an outlet end with the adapter assembly to be in fluid communication with the second selectable spray nozzle. Because the powder coating material in this second configuration is being supplied in dense phase, the second selectable forward section may include a member for adding air to the powder coating material when the powder coating material flows through the second selectable spray nozzle. The member for adding air may be disposed, for example, in the second selectable spray nozzle. An example of the member is a diffuser that comprises air porous material.
Another inventive concept of the present disclosure contemplates a configurable spray gun that uses many common components for two or more configurations, wherein one or more selectable configurations is for powder from a dense phase supply and the other configuration is for powder from a dilute phase supply. In an embodiment of this concept, it is to be noted that the configurable spray gun concept takes advantage of the simplicity of the selectable configurations so that the same rearward section may be used with a selectable forward section and selectable powder tube to provide either a dilute phase supply powder spray gun or a dense phase supplied powder spray gun. Additional embodiments of this concept are presented herein, including embodiments for a manual spray gun and automatic spray guns that may be selectively configured to use either a slot type spray nozzle or an air cap, all of which may use dense phase delivery to the spray gun.
In another embodiment of the configurable spray gun, in order to change over or select one of the selectable configurations with dense phase delivery, the assembler easily slides a smaller dense phase powder tube (the second selectable powder tube) through the larger dilute phase powder tube (the first selectable powder tube) that extends through the rearward section. The second selectable spray nozzle and adapter, or alternatively an air cap, are then installed on the forward end of the rearward section to complete a second selectable spray gun configuration. The second selectable spray nozzle or the air cap may alternatively be used to select the location of an electrode tip. For the second selectable spray gun configuration (spray nozzle or air cap), the electrode tip may optionally be disposed outside the second selectable spray nozzle, while for the first selectable spray gun configuration the electrode tip may optionally be disposed inside the first selectable spray nozzle.
Another inventive concept contemplates a spray gun for a dense phase powder supply that has a selectable forward section that is adapted to spray dilute phase powder. In an embodiment of this concept, a first powder tube having a first cross-sectional area extends through a second powder tube having a second cross-sectional area that is larger than the first cross-sectional area. The smaller cross-sectional area powder tube is connectable to a dense phase powder supply, and a first selectable forward section may include a spray nozzle or an air cap that dilutes the dense phase powder. When the smaller cross-sectional powder tube is removed, the larger cross-sectional powder tube is connectable to a dilute phase powder supply, and a second selectable forward section may be used that is adapted to operate with a dilute phase powder supply. Additional embodiments of this concept are disclosed herein.
In another embodiment, a spray gun for use with a dense phase powder supply is configurable using a selectable forward section that is adapted to spray dilute phase powder. In an embodiment of this concept, a first powder tube having a first cross-sectional area extends through a second powder tube having a second cross-sectional area that is larger than the first cross-sectional area. Additional embodiments of this concept are disclosed herein.
In another embodiment, the selectable forward section may have at least two selectable configurations, for example a spray nozzle or an air cap. And in a further embodiment, the selectable forward section includes structure for adding atomizing or dilution air to the dense phase powder flow delivered to the spray gun from a dense phase delivery system. In another embodiment, the selectable forward section is used with a rearward section that may be though need not be the same rearward section for all the selectable configurations of the spray gun, but using a selectable powder tube depending on whether the spray gun is configured for dense phase delivery or dilute phase delivery.
While various aspects and features and concepts of the inventions are described and illustrated herein as embodied in various combinations in the exemplary embodiments, these various aspects, features and concepts may be realized in many alternative embodiments, either individually or in various combinations and sub-combinations thereof. Unless expressly excluded herein all such combinations and sub-combinations are intended to be within the scope of the present invention. Still further, while various alternative embodiments as to the various aspects and features of the invention, such as alternative materials, structures, configurations, methods, devices and so on may be described herein, such descriptions are not intended to be a complete or exhaustive list of available alternative embodiments, whether presently known or later developed. Those skilled in the art may readily adopt one or more of the aspects, concepts or features of the various inventions into additional embodiments within the scope of the present inventions, even if such embodiments are not expressly disclosed herein. Additionally, even though some features, concepts or aspects of the inventions may be described herein as being a preferred arrangement or method, such description is not intended to suggest that such feature is required or necessary unless expressly so stated. Still further, exemplary or representative values and ranges may be included to assist in understanding the present inventions however, such values and ranges are not to be construed in a limiting sense and are intended to be critical values or ranges only if so expressly stated. Additionally, even though some features and aspects and combinations thereof may be described or illustrated herein as having a specific form, fit, function, arrangement or method, such description is not intended to suggest that such descriptions or illustrated arrangements are required or necessary unless so expressly stated. Those skilled in the art will readily appreciate additional and alternative form, function, arrangement or methods that are either known or later developed as substitute or alternatives for the embodiments and inventions described herein.
With reference to
The selectable spray gun configurations disclosed herein are noted as being a first selectable spray gun configuration and a second selectable spray gun configuration (there also is a third selectable configuration as described below). Each selectable spray gun configuration includes a selectable spray nozzle or air cap, a selectable powder flow path or selectable powder tube, and a selectable forward section. For ease of reading we oftentimes will use a shorthand reference to the “first” and “second” parts, without repeating the word “selectable” every time, it being understood that reference to first and second parts refer to the parts as used in the first and second selectable spray gun configurations respectively.
Although
An exemplary embodiment of a first selectable spray gun configuration as represented in
A spray gun may be designed to function as a dilute phase delivery spray gun using dilute phase powder flow from a dilute phase pump, for example, a Venturi pump. Alternatively, a spray gun may be separately and distinctly designed as a dense phase delivery spray gun that receives a dense phase powder flow from a dense phase pump. There are significant differences between the two spray gun designs due to the characteristics of the powder flow received from the delivery system, and therefore the spray gun designs, and especially the spray nozzles and the powder tubes and hoses, are different for dense phase and dilute phase delivery, spraying and coating operations. This has resulted in the need for having spray gun parts inventory for both style spray guns. In the exemplary embodiment of
The first spray gun 10 can be thought of as having a first selectable forward section 26 and a rearward section 28. The first selectable forward section 26 includes the first spray nozzle 20, and may also include an optional charging electrode 30 that receives electrical energy from a high voltage multiplier 32 that is electrically connected with the electrode 30. In typical spray guns, the multiplier 32 may be located in the rearward section 28. In
We present herein the concept of a configurable spray gun that can have two or more selectable spray gun configurations. More configurations may be used as desired, but for purposes of this disclosure we present three exemplary selectable spray gun configurations. An important benefit of the configurable spray gun is to realize significant savings and use of common parts which can reduce having different parts inventories for different spray guns. Not only can there be selectable configurations when putting a spray gun together, but the spray guns can be easily and conveniently configured, re-configured or converted between the selectable configurations. In the exemplary embodiments, we start with a known design for a dilute phase spray gun 10 that operates with a dilute phase powder flow that is input to the rearward section from a dilute phase pump as a first selectable spray gun configuration. We further provide the ability to easily and conveniently convert or configure the dilute phase spray gun 10 into a second selectable spray gun configuration 40, or second spray gun 40 for short (
It is important to note that although the exemplary embodiments herein illustrate a prior art spray gun 10 as one of the selectable spray gun configurations, such is for convenience and is not required. The configurable spray gun concept of the present disclosure may be realized by providing a first selectable spray gun configuration that is operable with a dilute phase powder flow input, even if it is a wholly new design, and also providing a second selectable spray gun configuration with structure to convert or alternatively configure or re-configure the first spray gun configuration to operate with a dense phase powder flow input, in accordance with the teachings herein. Also, the reference as to which selectable configuration is “first” or “second” or “third” is arbitrary and is used simply as a convenient reference to distinguish the selectable spray gun configurations.
In accordance with this inventive concept of the present disclosure, and in reference to
It is a significant feature and benefit of the present inventions, although not necessarily required, that the selectable spray gun configurations 10, 40 of
The second selectable forward section 44 of the second spray gun 40 may include the second selectable spray nozzle 42 having a spray orifice 42a and an electrode 46. Because the powder flow must dilute over a shorter distance as compared with the first spray gun 10, it may be desirable to dispose the electrode tip 46a outside the spray nozzle 42. In the first spray gun 10 of
Powder coating material P will be supplied to the second selectable forward section 44, including the second selectable spray nozzle 42, through a second selectable powder tube 48. The second powder tube 48 includes an inlet end 48a connectable to a dense phase pump 50, for example, using a dense phase powder supply hose 52. The powder flow at the outlet end 48b of the second powder tube 48 will be dense phase. In order to spray the dense phase powder, air may be added to the powder flow. The second spray nozzle 42 may include a diffuser 54. The diffuser 54 may be, for example, a frusto-conical body that is made of a material that is porous to air. The diffuser 54 therefore acts as both an expansion chamber and a member for adding air to the powder flow. The diffuser 54 may be disposed within the second spray nozzle 42. Alternative structure as needed may be used for adding air into the dense phase powder other than a diffuser 54.
The second powder tube 48 for the second spray gun 40 may have a smaller diameter D2 as compared to the first powder tube 14 of the first selectable spray gun configuration. As part of the configuration of the second spray gun 40, the second powder tube 48 may be inserted into the second spray gun 40 through the back end of the rearward section 28′. The second powder tube 48 can be pushed forward through the inside space of the larger diameter first powder tube 14 in a telescoping manner as illustrated in
It should be noted that when we refer herein to a dense phase pump, we refer to a pump that produces a powder flow that has a higher ratio of powder to flow air as compared with a dilute phase pump, for example a common Venturi style powder pump. As it pertains to the present disclosure, a dense phase powder flow will use a powder hose from an outlet of a dense phase pump to an inlet end of the spray gun, as well as a powder flow passage within the spray gun, that have a smaller diameter or cross-sectional area than the powder hose and the powder flow passage in the spray gun used with a Venturi or other dilute phase pump.
With reference to
The first spray gun 10 may be but need not be realized in the form of the ENCORE® model spray gun which is commercially available from Nordson Corporation, Westlake, Ohio, and is well known to those in the art. Therefore, a detailed description of that spray gun is not required to understand and practice the inventions of the present disclosure. We provide the description of the spray gun 10 as it pertains to the parts that are associated with the selectable configurations.
The first spray gun 10 may include the first selectable forward section 26 and the rearward section 28 which includes a bar mount assembly 60. The bar mount assembly includes a mount bracket 62. A rear gun body 64 (which may correspond to the rear gun body 13 in
With reference to
We note here that although the exemplary embodiments disclose various designs for the spray nozzles and air caps used for spraying the powder coating material, whether received as dense phase or dilute phase powder flow, these are but a few examples of many known or later developed spray nozzle and air cap designs that may be used to carry out the present inventions.
At this point, some of the differences between a dilute phase spray nozzle and a dense phase spray nozzle are useful to understand. In a spray gun for powder that is supplied with dilute phase delivery, for example from a Venturi or other dilute phase powder pump, for example the ENCORE® model spray guns discussed herein, the spray nozzle may be designed to provide a desired spray pattern through a slot or other spray outlet 22 in the spray nozzle 20. The powder flow into the spray nozzle tends to have a high velocity and a large volume of flow air, thus providing a lower powder/flow air ratio or in other words a lean mix. The spray nozzle typically then does not have atomizing air or dilution air added because the powder flow is already dilute. The spray nozzle will tend to dissipate some of the energy of the powder flow as it exits the powder tube, and then form a desired spray pattern, often like a cloud of powder coating material. Typically the electrode tip will be disposed within the spray nozzle.
For a dense phase spray gun used with a dense phase delivery, the powder tube can serve as the spray outlet because the dense phase powder flow may appear as a liquid-like or stream-like flow. In this case, and air cap may be used to apply pressurized air to atomize or dilute the powder flow and to shape the spray pattern just forward of the powder tube outlet end, with the electrode tip typically being disposed exterior the front end of the spray gun. In other cases, a dense phase spray nozzle may include a source of atomizing or dilution air in the nozzle for diluting the spray powder flow before it exits the spray nozzle and is exposed to the electrode.
Again referencing
The first powder tube 14 may be positioned and held adjacent to the spider 70 by a retaining seal member 102. The spider 70 is captured between the spray nozzle 20 and a front end of the front gun body 68 when the spray nozzle nut 72 is tightened onto the front gun body 68. This also applies an axial load against the first powder tube 14 to help seat the spider 70 in the retaining seal 102.
It should be noted at this time that the exemplary embodiments herein illustrate components that are of a selected shape and size as needed for particular spray gun designs. However, in terms of providing a spray gun design that can selectively be configured to operate with a dilute phase or dense phase spray gun, the choice of which parts may be the same and which parts are swapped may be determined based on the overall spray gun functionality desired.
A basic embodiment then for the configurable spray gun concept presented herein is the use of a selectable powder tube, a selectable spray nozzle and an adapter member that facilitates a configuration change when needed. The configuration change between a dilute phase powder tube and a dense phase powder tube allows the dense phase powder tube to be slid through the larger diameter dilute phase powder tube, thus allowing for minimal change in the rearward section 28, which is the common section of the two selectable spray gun configurations.
This also emphasizes that a spray gun that is connectable to a dense phase supply into a spray gun that is otherwise configured to spray powder from a dilute phase supply, is embodied in a basic form by providing a powder tube of a smaller diameter being inserted through a powder tube of a larger diameter up to the spray nozzle.
With reference next to
The second forward section 44 is best illustrated in
The adapter tube holder 106 may be shaped similar to the spider 70 and is held in place between the second spray nozzle 42 and the front end portion 109 of the front gun body 68. The retaining seal 102 may join the back end of the adapter tube holder 106 with the first powder tube 14 in a manner similar to the spider 70 in the first spray gun 10. Note that the front gun body 68 may be the same as is used for the first spray gun 10 as part of the rearward section 28, 28′ that is common to both selectable spray gun configurations. An adapter tube 108 is supported inside the adapter tube holder 106. The second powder tube 48 includes a forward portion 110 with an open end. A back end 108a of the adapter tube 108 may be snugly seated in the forward portion 110 of the second powder tube 48. For example, the second powder tube 48 may comprise an elastic material that allows a barbed end 112 to be inserted into the open end of the forward portion 110 of the second powder tube 48. The elastic material may assist the second powder tube 48 to conform to the shape of the barbed end 112. The adapter tube 108 and the adapter tube holder 106 comprise a selectable adapter assembly 107 that interfaces the second powder tube 48 and the second spray nozzle 42.
A diffuser support 114 is disposed in the second spray nozzle 42. The diffuser support 114 seats in a passage 116 in the second spray nozzle 42. A seal 118, such as an o-ring seal, is provided to form a seal interface between the passage 116 wall and the diffuser support 114. The forward end of the diffuser support 114 provides a first recess or cavity 120. An optional member 122, also referred to herein as a diffuser (also see the discussion regarding a diffuser 54 with respect to
The member or diffuser 122 may be provided as a hollow frusto-conical wall 130 that is made of an air permeable material, such as sintered polyethylene for example. An air tube 132 extends from a back end of the second spray gun 40 and is connectable to a supply of pressurized air (which for the ENCORE® model spray gun is used for electrode wash air). The forward end of the air tube 132 is attached to an air fitting 134. The air fitting 134 opens to a cavity 136 that is provided between the front end of the front gun body 68 and the adapter tube holder 106. In the first spray gun 10, the pressurized air through the air tube 132 may be used as electrode wash air as is known. The adapter tube holder 106 includes one or more air passages 138 that open to an adapter tube holder socket 140 that receives the back end 142 of the diffuser support 114. The diffuser support 114 also includes one or more air passages 144 that open to the first cavity 120 of the diffuser support 114. By this arrangement, pressurized air that is applied to the air tube 132 passes through the air fitting 134 into the air cavity 136, through the air passages 138 into the socket 140, and from the socket 140 through the air passages 144 and into the first cavity 120 of the diffuser support 114. The pressurized air flows through the air pervious material of the diffuser 122 and into the interior volume 146 of the diffuser 122 to mix with the powder flow for dilution or atomizing air. Note that the electrode coiled end 154 sits in a passage 156 which is in fluid communication with the socket 140, so that pressurized air from the air tube 132 still may be used to provide electrode wash air. Therefore, the pressurized air from the air tube 132 may serve both as electrode wash air and also as the atomizing or dilution air for the dense phase powder flow that enters the second spray nozzle 42.
The second spray nozzle 42 will typically be somewhat longer than the first spray nozzle 20 because of the diffuser 122. Because the spider 70 is not used in the second spray gun 40, a modified electrical connection between the multiplier 32 and the electrode 46 is provided. The multiplier output contact pin 98 makes contact with a conductive disk 148. An extension spring 150 is provided in contact with the conductive disk 148 at one end and a conductive ring 152 at the other. The conductive ring 152 also makes electrical contact with a coiled spring end 154 of the electrode 46. The electrode 46 extends through a passage 156 to the front of the second spray nozzle 42 so that the electrode tip 46a is disposed outside of the second spray nozzle 42.
An adapter key 158 arrangement, for example, a pin and slot configuration, may be used to key the adapter tube holder 106 to the front gun body 68. This key arrangement 158 can be used to assure that the conductive disk 148 is aligned with the extension spring 150 during assembly. Also, the key arrangement 158 may be used prevent a torsion or twist from being applied to the second powder tube 48 when the second spray nozzle 42 is assembled onto the second spray gun 40. This twist could occur if the adapter tube holder 106 is not keyed to the front gun body 68 because of the connection between the adapter tube 108 and the second powder tube 48.
A comparison of
It should be noted that the differences between the first selectable spray gun configuration 10 and the second spray gun configuration 40 all relate to easily accessible components on the outside front end of the spray gun, with the exception of inserting the second selectable powder tube 48 up through the first selectable powder tube 14 when the second spray gun configuration is to be used. The selectable forward sections are readily configured by removing the spray nozzle and the associated spider or adapter assembly and installing the alternative selectable parts for the desired configuration.
Another benefit of the selectively configurable spray gun concept is that for the second spray gun 40, it will be noted that the second selectable flow path includes the second powder tube 48 and the adapter tube 108 which is part of the adapter assembly 107. This allows the adapter tube material to be selected based on the type of powder coating material being sprayed, be it organic powder or porcelain enamel powder. The powder flow does not impact surfaces as would occur when a spider is used, so the adapter support housing 106 will not exhibit wear.
With reference to
In order to provide a second selectable forward section that accommodates either an air cap or a slot style spray nozzle, we illustrate additional embodiments and modifications to the second selectable forward section 44 as compared with the embodiments of
The air cap style configurable spray gun 200 of
In order to further realize the benefit of being able to provide multiple selectable spray gun configurations that share many common components, the second selectable forward section 202 has the benefit that the spray gun 200 may have either an air cap configuration or a slot style spray nozzle configuration by simply selecting which front end to use. Moreover, with the modified second selectable forward section 202, the forward section can now accept or support spray nozzles and air caps that were previously designed and are in use with the PRODIGY® model spray guns available from Nordson Corporation, Westlake, Ohio. This further enhances the savings of not needing special parts and inventory for different spray gun configurations because now a spray gun, for example an ENCORE® model spray gun, that is capable of spraying dilute phase powder from a dilute phase powder supply like a Venturi pump, can be selectively configured to spray dense phase powder from a dense phase powder supply and spray the powder through a spray nozzle or air cap that is otherwise usable with dense phase spray guns, for example a PRODIGY® model spray gun.
With reference then to
The conductive ring 210 includes one or more air passages 212 so that pressurized air that is supplied from the air tube 132 passes through the air passages 138 in the adapter tube holder 206, through a space 140 between the air passages 138 and the conductive ring 210, and then through the conductive ring air passages 212 and out the air cap 204. The air cap 214 includes horns 216 with air passages 218 that are in fluid communication with the air passages 212 in the conductive ring 210. This allows the atomizing air to diffuse the dense phase powder as the powder flow exits the outlet end 108b of the adapter tube 108. A seal 214 such as an o-ring for example may be used to force the pressurized air that passes through the adapter holder 206 into the air cap 204. In this way, the pressurized air from the air tube 132 may be used as both electrode wash air and as the dilution or atomizing air for the dense phase powder that exits the adapter tube 108 into the air cap 204.
With this modified adapter tube holder 206 then, a conventional PRODIGY® model air cap may be used with the second selectable forward section 202. Of course, other air caps may be used as needed for particular applications. Note that when the air cap 204 is used, there is no need for the air diffuser support 114. In order to couple electrical energy to the electrode 46, we provide a hollow insert 220 in a cavity 222 of the air cap 204. This insert 220 receives the powder flow that exits the adapter tube end 198b, and may further optionally be used to support the electrode 46 for electrostatic coating operations. The electrode 46 is received in a passage 156 and has a coiled spring end 154 that makes contact with the conductive ring 210. In addition, the insert 220 may be provided with an inwardly tapered, for example frusto-conical, forward opening 223 that helps to shape the powder flow pattern and keep the powder directed toward the centerline P of the powder flow path as the powder exits the air cap 204. This directed flow can improve the ability to electrostatically charge the powder.
With reference to
The selectable second forward section 224 for the third configurable spray gun may include the same adapter tube holder 206, conductive ring 210, air passages 212, and seal 214 as the embodiment of
Therefore, the modified adapter tube holder 206 in
With reference to
The manual spray gun 230 illustrated in
The nozzle assembly 236 may use the same adapter tube holder 206 and related components as the embodiments of
It will be also noted that in a manner similar to the automatic spray gun embodiments herein (
We have referred to a dense phase powder pump 50 in the above disclosure, which is also commonly known as high density powder pumps. There are many different dense phase pumps available commercially, and one such pump is described in U.S. Pat. No. 7,997,878 issued on Aug. 16, 2011, to Terrence M. Fulkerson for DENSE PHASE POWDER PUMP WITH SINGLE ENDED FLOW AND PURGE; and U.S. Pat. No. 7,150,585 issued on Dec. 19, 2006, to Kleineidam et al. for PROCESS AND EQUIPMENT FOR THE CONVEYANCE OF POWDERED MATERIAL, the entire disclosures of which are fully incorporated herein by reference. With reference to
The inventions have been described with reference to the exemplary embodiments. Modifications and alterations will occur to others upon a reading and understanding of this specification and drawings. It is intended to include all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
The present application is a national phase entry under 35 U.S.C. §371 of, and claims priority to, pending International Application No. PCT/US2013/030199 filed Mar. 11, 2013, for DENSE PHASE OR DILUTE PHASE DELIVERY THROUGH A POWDER GUN, which claims the benefit of U.S. Provisional patent application Ser. No. 61/672,037 for DENSE PHASE OR DILUTE PHASE DELIVERY THROUGH A POWDER GUN filed on Jul. 16, 2012, the entire disclosures of which are fully incorporated herein by reference. This application claims the benefit of U.S. Provisional patent application Ser. No. 61/672,037 for DENSE PHASE OR DILUTE PHASE DELIVERY THROUGH A POWDER GUN filed on Jul. 16, 2012, the entire disclosure of which is fully incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2013/030199 | 3/11/2013 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2014/014502 | 1/23/2014 | WO | A |
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| 20150190823 A1 | Jul 2015 | US |
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| 61672037 | Jul 2012 | US |
