Atomization system having a sensor air shield

Abstract

The sensor air shield assembly (42) includes a housing having a sensor mounting portion. A sensor (32) is supported at the sensor mounting portion. The sensor has a lens (34). An air inlet is provided in the housing (44). An air passage is provided in the housing (44) and communicates with the air inlet. A discharge orifice is provided in the housing and communicates with the air passage. The discharge orifice is disposed in the housing adjacent the sensor lens and is directed such that air exiting the discharge orifice passes across the sensor lens (34).

Description

[Background technology]

[0001] Spray systems are used in a variety of applications to emit fluids onto target objects. For example, in food processing applications, the spray system may include one or more spray devices that emit ingredients or other coatings onto food objects. In such applications, the continuous emission of process fluids from the spray devices can result in a significant amount of overspray that does not land on any target objects. Such overspray can be costly and wasteful. To help reduce or substantially eliminate this overspray, it is desirable to trigger the emission of process fluids from the spray device only when an object is present within the target area of ​​the spray device. One way this can be accomplished is by an optical sensor. The optical sensor detects the presence of an object within the target area and then generates a signal that is used to activate the spray device. When the object leaves the target area, the optical sensor can send a further signal to deactivate the spray device.

[0002]

[0002] While the use of sensors can help reduce overspray, sensors can be difficult to implement in applications where they are mounted in close proximity to their respective spray devices. Particularly with such placements, the discharge of the spray devices can generate a certain amount of blowback, which creates a fine mist or cloud of process fluid around the sensor. Over time, the blowback of process fluid can build up on the lens of one or more of the optical sensors. This buildup can disrupt the sensor's ability to function properly. Summary of the Invention

[0003] [Objective of the Invention] SUMMARY OF THE DISCLOSURE

[0003] In view of the above, it is a general object of the present invention to provide a spray system that includes a sensing system that reliably detects the presence of an object to be sprayed within a target area.

[0004] A related object of the present invention is to provide a spray system of the type described above in which the sensing system is capable of operating in applications in which the spray system produces significant process fluid blowback spray.

[0005] It is a further object of the present invention to provide a spray system of the type described above which includes a sensing system which can be easily adapted to a wide variety of sensor types and mounting arrangements.

[0006] It is a further object of the present invention to provide a spray system including a sensing system which is relatively simple in design and inexpensive to manufacture.

[0007] Other objects and advantages of the present invention will become apparent from the following detailed description when considered in conjunction with the drawings, in which: The objects identified are not intended to be limitations on the present invention. [Brief explanation of some figures in the drawing] [Brief description of the drawings]

[0008] [Figure 1] 1 is a perspective view of a spray system including a plurality of spray nozzle assemblies each having an associated actuation sensor air shield assembly in accordance with the teachings of the present invention; [Diagram 2] FIG. 2 is a side view of the spray system of FIG. 1. [Diagram 3] FIG. 2 is a side view of one spray nozzle assembly and associated actuation sensor air shield assembly of FIG. 1. [Figure 4] FIG. 4 is a side perspective view of the differential sensor air shield assembly of FIG. [Diagram 5]FIG. 4 is a partially exploded perspective view of the spray nozzle assembly and associated active sensor air shield assembly of FIG. 3 with the attachment mechanism removed from the sensor air shield assembly for ease of reference. [Figure 6] FIG. 6 is a side cross-sectional view of the differential sensor air shield assembly of FIG. [Figure 7] 1 is a partial cutaway side view of an alternative embodiment of an actuated sensor air shield assembly and sensor in accordance with the teachings of the present invention. [Figure 8] FIG. 8 is a bottom view of the operational sensor air shield assembly and sensor of FIG. 7 showing a portion of the housing. [Figure 9] FIG. 8 is a side perspective view of the active sensor air shield assembly of FIG. 7 with the sensor removed for ease of reference. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Detailed Description of the Invention]

[0017] 1 and 2 of the drawings, there is shown an exemplary embodiment of a spray system 10 constructed in accordance with the present invention. The illustrated spray system 10 includes a plurality of spray nozzle assemblies 12. The plurality of spray nozzle assemblies 12 are supported in a laterally spaced relationship along a header 14 that extends above a conveyor 16. The conveyor 16 can be used to transport a plurality of objects 18 to be sprayed. More specifically, the conveyor 16 transports the objects 18 through an area where the spray nozzle assemblies 12 discharge process fluids toward the objects 18. In one example, the object 18 can be a food product and the process fluid can be a coating to be applied to the food product. However, the present invention is not limited to spraying such liquids or use in such environments. Rather, the spray system 10 of the present invention can be used with a wide variety of spray targets and process fluids.

[0010]

[0018] In this case, the header 14 is disposed transversely to the direction of travel of the conveyor 16 and is supported by upright members 20 disposed on either side of the conveyor 16. The illustrated upright members 20 are configured to allow the height of the header 14 to be adjusted relative to the conveyor 16. In this manner, the position of the spray nozzle assembly 12 relative to the object 18 to be sprayed can be adjusted as desired. The illustrated arrangement further includes four spray nozzle assemblies 12 on the header 14, although any number may be used. The spray system 10 of the present invention is not limited to use with a header and conveyor arrangement as shown in Figures 1 and 2. On the contrary, the spray system 10 of the present invention may be used with any suitable arrangement for supporting the spray nozzle assembly 12 relative to the object 18 to be sprayed and for delivering the object 18 to a target area.

[0011]

[0019] Each illustrated spray nozzle assembly 12 is connected to a process fluid storage and delivery unit 24 via a fluid supply line 22, as shown in Figure 1. The process fluid storage and delivery unit 24 may be configured to store pressurized process fluid and deliver it to the individual spray nozzle assemblies 12 in a known manner. Any suitable device for delivering process fluid to the spray nozzle assemblies 12 may be used.

[0012]

[0020] Each spray nozzle assembly 12 is generally configured to emit a process fluid provided from a fluid exhaust delivery unit 24 when actuated. In the illustrated embodiment, as shown in Figures 3 and 5, each spray nozzle assembly 12 includes a nozzle body 26. The nozzle body 26 has a fluid inlet 28 at one end in communication with the process fluid supply line 22 and a nozzle tip 30 at an opposite end. The nozzle tip 30 is configured to define a nozzle opening through which the process fluid is emitted. Each spray nozzle assembly 12 and associated nozzle tip 30 may define a respective spray target area into or onto which the process fluid is emitted (the emitted process fluid is generally referenced as 35 in Figure 5). The size and shape of this spray target area will vary based on the configuration of the spray nozzle assembly 12 and nozzle tip 30. The spray nozzle assembly 12 and nozzle tip 30 may be configured to provide any desired spray pattern, and as will become apparent below, the present invention is not limited to any particular spray nozzle assembly 12 or nozzle tip 30 configuration.

[0013]

[0021] As best shown in FIG. 2, each spray nozzle assembly 12 may have an associated actuation sensor 32 to determine whether one or more objects 18 to be sprayed are within the target area of ​​the spray nozzle assembly 12. The actuation sensor 32 may be an optical sensor positioned, oriented, and configured to rapidly detect when an object 18 to be sprayed is within the target area of ​​the associated spray nozzle assembly 12. To this end, the actuation sensor 32 may have at least one lens 34 or window for either emitting or detecting light (see FIGS. 5 and 6). The light emitter may be, for example, a light emitting diode or a solid state laser, and the light detector may be a phototransistor. However, any type of optical sensor may be used, including, for example, a laser sensor, a photoelectric sensor, or a color (e.g., RGB) detecting sensor.

[0014]

[0022] To reduce wasteful overspray, each spray nozzle assembly 12 and associated actuation sensor 32 may be configured to actuate the spray nozzle assembly 12 to emit process fluid only when an object to be sprayed 18 is detected within a target area associated with the spray nozzle assembly. More specifically, the actuation sensor 32 may be configured to generate a detection signal when an object to be sprayed 18 is within the target area, and the associated spray nozzle assembly 12 may be configured to actuate when the detection signal is generated. In one embodiment, as shown in FIG. 1, the actuation sensor 32 communicates with a sensor controller 36. The sensor controller 36 further communicates with a spray controller 38 which directs various operational aspects of the spray nozzle assemblies 12. In this arrangement, when the spray controller 38 receives a detection signal via the sensor controller 36, the spray controller 38 directs actuation of the appropriate spray nozzle assembly 12. Although the illustrated embodiment includes separate spray and sensor controllers, a single controller incorporating both sensing and spraying functions may be used. Additionally, the sensor controller 36 and spray controller 38 may be configured to activate an associated spray nozzle assembly to cause a single process fluid discharge or multiple process fluid discharges for each detection signal. Additionally, deactivation of the appropriate spray nozzle assembly 12 may be based on a further signal from the activation sensor 32, such as a signal indicating that the object 18 is no longer in the target area, or alternatively, deactivation may be based on a timer.

[0015]

[0023] To help ensure accurate detection, in the illustrated embodiment, the actuation sensor 32 is positioned in close proximity to the associated spray nozzle assembly 12, as shown in Figures 2 and 3. However, such positioning may result in blowback spray 40 (see Figures 5 and 6) building up on the lens 34 of the actuation sensor 32 or otherwise obscuring the sensor's line of sight 43 to the target area of ​​the spray nozzle assembly 12 (see Figures 5 and 6). To help avoid this problem, a sensor air shield assembly 42 (shown in Figures 3-6) is provided. The sensor air shield assembly 42 is configured to support the actuation sensor 32 and direct a flow of pressurized air around the lens 34 of the actuation sensor 32 to shield against blowback process fluid spray 40 or other environmental substances that may interfere with the ability of the actuation sensor to function properly. Although the present invention has particular applicability for applications in which it is desirable to locate the actuation sensor 32 in close proximity to the spray nozzle assembly 12, it may also be used in applications in which the actuation sensor 32 is located away from the spray nozzle assembly 12 and yet is still sensitive to process sprays or other environmental contaminants that may deposit on or otherwise obscure the lens 34 of the actuation sensor 32.

[0016]

[0024] To support the actuation sensor 32 in an operative position relative to the spray nozzle assembly 12 and its associated target area, the sensor air shield assembly 42 includes a housing 44 that defines a sensor mounting portion, in this case a sensor receptacle 46, on which the actuation sensor 32 may be supported. The sensor receptacle 46 is configured so that the actuation sensor 32 may be oriented in a desired orientation relative to the target area. In this case, as shown in Figures 3 and 5, the sensor receptacle 46 is configured so that the actuation sensor 32 remains centered in a vertical relationship to the target object. In the illustrated embodiment, the housing 44 has an elongated form and the sensor receptacle 46 is defined by a channel in a side of the housing 44 extending longitudinally therethrough, with the actuation sensor 32 disposed in a lower portion of the channel with the lens 34 (see Figure 5) of the actuation sensor facing downward. The sensor receptacle 46 is open at its lower end, as best shown in FIG. 5, so that the sensor lens 34 can have a line of sight 43 to the corresponding target area. The actuation sensor 32 may be secured to the sensor receptacle 46 by any suitable fastener, such as, for example, a set screw 48 (see FIG. 4). The configuration of the sensor receptacle 46 may vary depending on the configuration of the actuation sensor 32 used. In the illustrated embodiment, the housing 44 of the sensor air shield assembly 42 further includes an electrical connection 50 at its upper end, as shown in FIGS. 3 and 4. The electrical connection 50 provides power to the actuation sensor 32 and connects the actuation sensor 32 to the sensor controller 36.

[0017]

[0025] To secure the sensor air shield assembly 42 to the header 14, the sensor air shield assembly 42 may include an adjustable mounting mechanism 52. As shown in FIG. 4, the illustrated mounting mechanism 52 includes an L-shaped bracket 54 secured to the rear surface of the sensor air shield housing 44. The L-shaped bracket 54 defines a slot in which the header 14, in this case configured as a flat bar, may be captured. The illustrated mounting mechanism 52 has the advantage of allowing the lateral position of the sensor air shield assembly 42 on the header 14 to be adjusted as desired. A thumb screw 56 is provided to secure the sensor air shield assembly 42 in a desired position. Of course, other adjustable mounting mechanisms may be used depending on the particular configuration of the header 14 or other support device for the sensor air shield assembly 42. It should be noted that for ease of reference, the mounting mechanism is not shown in FIGS. 5 and 6 as part of the sensor air shield assembly.

[0018]

[0026] To provide the necessary shielding air, the sensor air shield assembly 42 includes an air inlet 58, in this case located near the lower end of the housing 44, connectable to an air supply line 60, as shown in FIG. 4. The air supply line 60 is further connected to a conditioned air source 62 configured to deliver pressurized air to the sensor air shield assembly 42. In the illustrated embodiment, as shown in FIGS. 1 and 2, the air source 62 is located away from the sensor air shield assembly 42 on one of the upright members 20 supporting the header 14 and is configured to supply air to the multiple sensor air shield assemblies 42 located on the header 14. In other embodiments, each sensor air shield assembly 42 may have its own air source located adjacent to or integral with the sensor air shield assembly.

[0019]

[0027] To direct the shield air toward the lens 34 of the actuation sensor 32, the sensor air shield assembly 42 includes a shield air discharge passage 64 in communication with the air inlet 58. As best shown in FIG. 6, the shield air discharge passage 64 extends in a direction generally perpendicular to the line of sight 43 of the actuation sensor 32. Additionally, the shield air discharge passage 64 terminates in an air discharge orifice 66. The air discharge orifice 66 is positioned proximate to the lens 34 of the actuation sensor 32, in this case proximate to a side of the lens, and is positioned a distance in the direction of the line of sight of the lens such that air exiting the discharge orifice 66 passes across the lens of the sensor 32. The shield air discharge passage 64 has a cylindrical configuration to generate a consistent laminar airflow across the surface of the lens 34 of the actuation sensor 32 and the area near the surface of the lens 34 of the actuation sensor 32. In this context, laminar airflow refers to a constant airflow that does not mix with other nearby layers. This laminar shielding air flow helps keep the lens 34 clear and dry from process fluid blowback 40 from the discharge spray nozzle assembly 12 as well as other contaminants. In the illustrated embodiment, the shielding air discharge passage 64 has an upstream section with a relatively larger diameter and a downstream section with a relatively smaller diameter. This gradual reduction in diameter of the shielding air discharge passage 64 serves to increase the pressure of the shielding air as it moves from the air inlet 58 to the air discharge orifice 66. The air pressure required to adequately shield the lens 34 of the actuation sensor 32 depends on the droplet size of the blowback spray 40 or other contaminants present in a particular application. Thus, the pressure provided by the air source 62 and / or the configuration of the shielding air discharge passage 64 and air discharge orifice 66 may be adjusted as needed to accommodate the particular droplet size found in an application.

[0020]

[0028] To help shape the emitted shielding air, the sensor air shield assembly 42 includes an air deflector surface 68 downstream of the air discharge orifice 66. The configuration of the air deflector surface 68 in the illustrated embodiment is best shown in Figures 3 and 5. The illustrated air deflector surface 68 includes an upper portion 70 adjacent the discharge orifice and a lower portion 72 below or downstream of the upper portion. The upper portion 70 includes a sidewall disposed near the outer lateral edge of the lens 34, while the lower portion 72 has a sidewall that typically tapers outwardly as the lower portion 72 extends downwardly and away from the upper portion 70 and the air discharge orifice 66. Depending on the particular application, the configuration of the deflector surface 68 may vary depending on the desired shielding airflow characteristics. Additionally, the air deflector surface 68 is configured to ensure that it does not obstruct the line of sight 43 of the actuation sensor 32. In the illustrated embodiment, the air deflector surface 68 provides a relatively large opening around the lens 32 for operation of the actuation sensor 32. As will be appreciated, different actuation sensors 32 may have lines of sight 43 that extend at different angles relative to the housing 44 and sensor receptacle 46, and thus the configuration of the air deflector surface 68 may be adjusted to accommodate the line of sight of the desired actuation sensor.

[0021]

[0029] 7-9 illustrate an alternative embodiment of a sensor air shield assembly 120 according to the present disclosure that may be used in conjunction with an actuation sensor 122 and one or more associated spray nozzle assemblies. For example, the associated spray nozzle assembly may be configured as shown in FIGS. 3 and 5. Although configured somewhat differently, like the embodiment of FIGS. 3-6, the actuation sensor 122 of FIGS. 7 and 8 is an optical sensor having at least one lens 124 or window for either emitting or detecting light (see FIG. 8). As with the embodiment of FIGS. 3-6, the sensor air shield assembly 120 of FIGS. 7-9 is configured to support the actuation sensor 122 and direct a flow of pressurized air across the sensor's lens 124 to protect against blowback process fluid spray or other environmental substances depositing on or otherwise obscuring the lens 124.

[0022]

[0030] In the illustrated embodiment, the sensor air shield assembly 120 includes a housing 126 having an L-shaped configuration comprised of a first block 128 and a second block 130. More specifically, the housing 126 is configured to support the sensor 122 in a desired orientation such that the sensor has an open line of sight to a corresponding target area. With reference to FIGS. 7 and 9, in this case, the first block 128 of the housing 126 defines a mounting surface 132 to which the sensor 122 may be secured. For example, in the illustrated embodiment, the sensor 122 may be mounted to the mounting surface 132 by a removable fastener, such as a bolt 134, which may be received in a corresponding female threaded opening 136 in the mounting surface 132 of the first block 128. In FIG. 9, two pairs of threaded openings 136 are shown in the mounting surface 132, allowing for variability in the mounting arrangement based on the type of sensor used. Additionally, for securing the sensor air shield assembly 120 to a header as shown in Figures 1 and 2, the sensor housing 126 of Figures 7-9 uses the same adjustable mounting mechanism including an L-shaped mounting bracket as shown in Figure 4. The second block 130 of the housing 126 includes an air inlet 138 connectable to an air supply line 140.

[0023]

[0031] To direct the shield air across the lens 124 of the sensor 122, the housing 126 includes a shield air discharge passage 142. The shield air discharge passage 142 communicates with the air inlet 138 and terminates in an air discharge orifice 150. In this case, as shown in FIG. 8, the air discharge passage 142 includes a first section 144, a second section 146, and a third section 148. The first section 144 of the air discharge passage 142 is furthest upstream (with respect to the direction of air flow), has a generally cylindrical configuration, and communicates directly with the air inlet 138. The second section 146 is immediately downstream of the first section 144 and has a generally sector-shaped configuration that continuously widens outward as it extends in the downstream direction. A third section 148 of the air discharge passage 142 is immediately downstream from the second section 146 and, in the illustrated embodiment, is formed by a notch in the lower edge of the first block 128 and an upper surface of the second block 130 (see FIG. 9) that gives the third section a rectangular cross-sectional configuration (see FIG. 8). Similar to the embodiment of FIGS. 3-6, the discharge passage 142 of the embodiment of FIGS. 7-9 is configured to generate a substantially constant, laminar air flow toward a discharge orifice 150.

[0024]

[0032] The third section 148 of the air discharge passage 142 terminates in a discharge orifice 150 that is oriented and positioned to generate an airflow (referenced as 152 in FIGS. 7 and 8) across the lens of the sensor. To this end, as in the embodiment of FIGS. 3-6, the discharge orifice 150 is positioned proximate to the lens 124 of the sensor 122, as best shown in FIG. 7. More specifically, the discharge orifice 150 is positioned against a side of the lens 124 of the sensor 122 and spaced a distance along the line of sight of the lens 124. The illustrated discharge orifice 150 has a rectangular configuration (see FIG. 9) that, in conjunction with the configuration of the discharge passage 142, generates a knife-like fan-shaped airflow across the lens 124 of the sensor 122, as shown in FIG. 8. However, it should be understood that other discharge orifice configurations may be used, provided that a sufficient airflow across the lens of the sensor is generated to prevent the lens from becoming obscured.

[0025]

[0033] All references cited in this specification, including publications, patent applications, and patents, are herein incorporated by reference to the same extent as if each reference was individually and specifically indicated to be incorporated by reference and was set forth in its entirety herein.

[0026]

[0034] The use of the terms "a" and "an" and "the" and "at least one" and similar referents in the context of describing the present invention (particularly in the context of the claims below) should be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term "at least one" (e.g., "at least one of A and B") with a list of one or more items should be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" should be construed as open-ended terms (i.e., meaning "including, but not limited to"), unless otherwise noted. The recitation of ranges of values ​​herein, unless otherwise indicated herein, is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, and each separate value is incorporated herein as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or clearly contradicted by context. Any and all examples provided herein, or the use of exemplary language (e.g., "etc.") are intended merely to fully clarify the invention, and no limitation of the scope of the invention is asserted unless otherwise claimed in the claims. No language in the specification should be construed as indicating any element not claimed in the claims as essential to the practice of the invention.

[0027]

[0035] Preferred embodiments of the present invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those skilled in the art upon reading the foregoing description. The inventors expect that such variations will be utilized by those skilled in the art, and the inventors intend to carry out the invention in ways other than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or clearly contradicted by context.

Claims

1. A spray nozzle; a sensor air shield assembly, the sensor air shield assembly comprising: a housing having a sensor mounting portion; a sensor supported on the sensor mount and having a lens with a line of sight toward a target area of ​​the spray nozzle; an air inlet in the housing connectable to a source of regulated pressurized air; an air passage in the housing and in communication with the air inlet; a discharge orifice in the housing in communication with the air passage, the discharge orifice being positioned on the housing proximate to a lens of the sensor and directed so that air exiting the discharge orifice passes across the lens of the sensor; an air deflector surface downstream of the discharge orifice for shaping air exiting the discharge orifice toward a lens of the sensor; A spray assembly comprising:

2. The spray assembly of claim 1 , wherein the spray nozzle is actuated based on a signal generated by the sensor.

3. The spray assembly of claim 1 , wherein the sensor is located proximate to the spray nozzle.

4. 10. The spray assembly of claim 1, wherein the air passage extends in a perpendicular relationship to the line of sight of the sensor.

5. 10. The spray assembly of claim 1, wherein the air passage has a cylindrical section.

6. 6. The spray assembly of claim 5, wherein the cylindrical section is a first section, and the air passage further includes a second section downstream of the first section, the second section having a fan-shaped configuration that continuously widens outward as it extends in a downstream direction.

7. 7. The spray assembly of claim 6, wherein the air passage further includes a third section downstream of the second section, the third section having a rectangular cross-sectional configuration.

8. 8. The spray assembly of claim 7, wherein the discharge orifice has a rectangular configuration.

9. 10. The spray assembly of claim 1, wherein the sensor mounting portion is a receptacle that receives the sensor.

10. 10. The spray assembly of claim 1, wherein the sensor mounting portion is a mounting surface to which the sensor is attached by a removable fastener.

11. a housing having a sensor mounting portion; a sensor supported by the sensor mounting portion and having a lens; an air inlet provided in the housing; an air passage in the housing and in communication with the air inlet; a discharge orifice in the housing in communication with the air passage, the discharge orifice being positioned on the housing proximate to a lens of the sensor and directed so that air exiting the discharge orifice passes across the lens of the sensor; Equipped with a sensor air shield assembly, wherein the air passage has a first cylindrical section and a second section downstream of the first section, the second section having a fan-shaped configuration that continuously widens outward as it extends in a downstream direction.

12. A sensor air shield assembly as described in claim 11, wherein the sensor has a line of sight and the air passage extends perpendicular to the line of sight.

13. A sensor air shield assembly as described in claim 11, wherein the air passage further includes a third section downstream of the second section, the third section having a rectangular cross-sectional shape.

14. The sensor air shield assembly of claim 13 , wherein the discharge orifice has a rectangular configuration.

15. a housing having a sensor mounting portion for supporting a sensor; an air inlet provided in the housing; an air passage in the housing and in communication with the air inlet; a discharge orifice in the housing communicating with the air passage, the discharge orifice being positioned adjacent to the sensor mounting portion; Equipped with a sensor air shield assembly, wherein the air passage has a first cylindrical section and a second section downstream of the first section, the second section having a fan-shaped configuration that continuously widens outward as it extends in a downstream direction.

16. The sensor air shield assembly of claim 15 , wherein the air passage has a cylindrical section.

17. A sensor air shield assembly as described in claim 16, wherein the air passage further includes a third section downstream of the second section, the third section having a rectangular cross-sectional shape.

18. The sensor air shield assembly of claim 17 , wherein the discharge orifice has a rectangular configuration.

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