阅读说明：本技术 用于传送机式烤炉的传感器系统升级套件 (Sensor system upgrade kit for conveyor ovens ) 是由 卡西米尔·瓦尔特·卡兹米洛维奇 菲利普·卡西米尔·卡兹米洛维奇 于 2019-09-30 设计创作，主要内容包括：一种用于改装烤炉处理系统的套件,所述套件可以使用来升级温度监控能力。烤炉处理系统包括烤炉和传送机带。烤炉限定经加热的隧道。传送机带沿横轴行进穿过隧道。该套件至少包括多个传感器模块。传感器模块是细长主体,感测端部安装在烤炉内部。传感器模块单独地包括气体导管和电缆。气体导管联接到加压气体源。电缆联接到数据采集单元,该数据采集单元位于经加热的隧道外侧。(A kit for retrofitting an oven processing system that can be used to upgrade temperature monitoring capabilities. An oven treatment system includes an oven and a conveyor belt. The oven defines a heated tunnel. The conveyor belt travels along a transverse axis through the tunnel. The kit includes at least a plurality of sensor modules. The sensor module is an elongated body with a sensing end mounted inside the oven. The sensor module comprises solely a gas conduit and a cable. The gas conduit is coupled to a source of pressurized gas. The cable is coupled to a data acquisition unit located outside the heated tunnel.)

1. An oven treatment system, comprising:

an oven having a heated tunnel traversing therethrough;

a conveyor belt traveling transversely along a first axis through the heated tunnel;

a measurement system, comprising:

a plurality of sensor modules, the sensor modules individually comprising:

a housing comprising a substrate having a first side and a second side, the first side having a thermopile configured to output a first signal indicative of a surface temperature of an object on the conveyor belt relative to the substrate, the second side having a temperature sensor configured to output a second signal indicative of a temperature of the substrate, and a thermopile lens overlying the thermopile and aligned with an opening in the housing;

a housing enclosing the housing and including an opening aligned with the thermopile lens to allow infrared light from the object to reach the thermopile;

a gas conduit coupled to the housing; and

a cable coupled to the substrate;

a data acquisition unit coupled to the cable, the data acquisition unit receiving the first and second signals from the sensor module and outputting information indicative of a surface temperature of the object; and

a pressurized gas source coupled to the gas conduit whereby a flow of gas passes through the conduit, to the housing, and out of the opening in the enclosure, the flow through the opening preventing a buildup of contaminants on the thermopile lens.

2. The system of claim 1, wherein a distal end of a sensor module is mounted near an edge of the conveyor belt within a tunnel of the oven, the thermopile lens generally facing an upper surface of the conveyor belt.

3. The system of claim 1, wherein the sensor modules individually comprise a support on which the housing is mounted, the support comprising mounting features for mounting an end of the sensor module to a position adjacent to an edge of the conveyor belt, the housing surrounding the support.

4. The system of claim 3, wherein the support has a long axis and is mounted adjacent to an edge of the conveyor belt, the long axis being generally aligned with the first axis.

5. The system of claim 1, wherein the cable passes through at least a portion of the gas conduit.

6. The system of claim 1, wherein the gas conduit has a joint coupling a first conduit portion coupled to the housing, a second conduit portion coupled to the gas source, and the cable passing from the housing through the first conduit portion but not through the second conduit portion.

7. A method of retrofitting an oven treatment system having an oven defining a transverse heated tunnel and having a conveyor belt traveling through the heated tunnel along a first transverse axis, the method comprising:

installing a plurality of sensor modules in the oven treatment system, the sensor modules individually comprising: a housing comprising a substrate having a first side and a second side, the first side having a thermopile configured to output a first signal indicative of a surface temperature of an object on the conveyor belt relative to the substrate, the second side having a temperature sensor configured to output a second signal indicative of a temperature of the substrate, and a thermopile lens overlying the thermopile and aligned with an opening in the housing;

a housing enclosing the housing and including an opening aligned with the thermopile lens to allow infrared light from the object to reach the thermopile;

a gas conduit coupled to the housing; and

a cable coupled to the substrate;

coupling the cable to a data acquisition unit; and is

Coupling the gas conduit to a pressurized gas source, activation of the pressurized gas source causing gas to flow through the gas conduit and out of the opening in the housing to prevent gas-borne contaminants from accumulating on the thermopile lens.

8. The method of claim 7, wherein individually installing the plurality of sensor modules comprises: mounting a distal end of the sensor module including the housing and the enclosure to a position adjacent an edge of the conveyor belt within the transverse tunnel, the thermopile lens facing generally toward an upper surface of the conveyor belt.

9. The method of claim 7, wherein the sensor module individually comprises a support on which the housing is mounted, the support comprising a mounting feature, the method comprising attaching the mounting feature to a mounting component.

10. A kit for retrofitting an oven treatment system, the oven treatment system comprising: an oven defining a heated tunnel traversing therethrough; and a conveyor belt traveling laterally along a first axis through the heated tunnel, the kit comprising:

a plurality of sensor modules individually comprising a housing having a substrate with a first side and a second side, the first side having a thermopile configured to output a first signal indicative of a surface temperature of an object on the conveyor belt relative to the substrate, the second side having a temperature sensor configured to output a second signal indicative of a temperature of the substrate, and a thermopile lens overlying the thermopile and aligned with an opening in the housing;

a housing enclosing the housing and defining an opening aligned with the thermopile lens to allow infrared light from the object to reach the thermopile;

a gas conduit coupled to the housing; and

a cable coupled to the substrate.

11. The kit of claim 10, wherein the sensor modules individually comprise a support on which the housing is mounted, the support being housed within the housing.

12. The kit of claim 11, wherein first and second sides of the support correspond to the first and second sides of the substrate, the second side defining a recess for receiving the first side of the housing, the support defining an opening passing from the recess to the first side aligned with the thermopile lens.

13. The kit of claim 12, wherein a plurality of wires couple the substrate to the cable and are routed along the notch along the long axis of the support.

14. The kit of claim 12, wherein the support includes at least one mounting hole, the housing defining a corresponding mounting hole aligned with the mounting hole of the support.

15. The kit of claim 10, wherein the gas conduit includes a first portion extending between the housing and the fitting, the cable passing through the first portion of the gas conduit.

16. The kit of claim 15, wherein the gas conduit has a second portion extending from the fitting to be connected to a source of pressurized gas, the cable not passing through the second portion.

17. The kit of claim 15, wherein the fitting is a T-fitting.

18. The kit of claim 17, wherein the second portion of the gas conduit extends from the T-joint at approximately 90 degrees from the first portion of the gas conduit.

19. The kit of claim 17, wherein the cable extends from the tee joint in a direction generally along the direction of the first conduit.

Technical Field

The present disclosure relates to a belt oven for processing substrates such as printed circuit boards. More particularly, the present disclosure relates to a sensor system upgrade kit for installing sensors in tunnel ovens that are self-calibrating and insensitive to contamination from substrates being processed.

Background

High temperature belt ovens are widely used. A typical belt oven has a heated tunnel with a conveyor belt that passes through the tunnel at a controlled speed. Most belt ovens have a temperature monitoring function for the oven, but not necessarily for the object being processed by the oven. It is desirable to provide continuous monitoring of the parts being processed by the oven. This can sometimes be done by passing the temperature probe through an oven on the conveyor belt, but this is not feasible for continuous monitoring.

One challenge of sensor systems is the high temperatures and contamination inside the oven. This is particularly true for ovens used to reflow solder. The temperature may damage the electronics of a typical non-contact sensor. The oven temperature may exceed 200 degrees celsius. Some oven temperatures may exceed 250 degrees celsius or even 300 degrees celsius. Also, flux may deposit on the sensor components, which may reduce accuracy. It would be desirable to provide a monitoring system that can be used to upgrade older ovens, operate at these temperatures, and is not sensitive to contamination.

Disclosure of Invention

In a first aspect of the present disclosure, an oven treatment system includes an oven, a conveyor belt, and a measurement system. The oven has a heated tunnel passing therethrough. The conveyor belt traverses the tunnel along a first X axis. The measurement system includes a plurality of sensor modules, a data acquisition unit, and a source of pressurized gas. The sensor module individually includes a housing, a casing, a gas conduit, and a cable. The housing includes a substrate and a thermopile lens. The substrate has a first side and a second side. The first side of the substrate has a thermopile configured to output a first signal indicative of a surface temperature of an object on the conveyor belt relative to a temperature of the substrate. The second side of the substrate has a temperature sensor configured to output a second signal indicative of the temperature of the substrate. The thermopile lens covers the thermopile. The housing defines an opening located above the thermopile lens to allow infrared light to enter the opening and reach the thermopile. The housing encloses the housing and includes an opening that is aligned with the thermopile lens to allow infrared light from an object to reach the thermopile. The gas conduit is fluidly coupled to the housing. The cable is electrically coupled to the substrate. The data acquisition unit is electrically coupled to the cable to receive the first and second signals from the sensor module and output information indicative of a surface temperature of the object. A source of pressurized gas is coupled to the gas conduit such that the gas flows through the conduit, to the housing and out the opening in the housing. Flow through the opening in the housing prevents contaminants from accumulating on the thermopile lens.

The sensor modules individually have an elongated body including a proximal end and a distal end. The distal end includes a temperature insensitive housing and an outer shell. The distal end is mounted in a heated tunnel. The proximal end is located outside the heated tunnel where it is coupled to sensor electronics (data acquisition unit) and a source of pressurized gas. The sensor electronics are sensitive to temperature. Thus, the elongated structure of the sensor module allows for physical and spatial isolation between the temperature insensitive distal end and the temperature sensitive sensor electronics.

In one embodiment, the oven treatment system has been upgraded using a kit. The kit includes at least a plurality of sensor modules. The kit may also include sensor electronics (data acquisition unit) and a gas source.

In another embodiment, the distal end of the sensor module includes a housing. The distal end is mounted within the tunnel of the oven adjacent the conveyor belt edge. The thermopile lens is typically facing the upper surface of the object on the conveyor belt or the position of the upper surface of the conveyor belt. The thermopile lens has an optical axis that is aligned downward and along a second transverse axis that is transverse to the first axis. The optical axis defines an oblique angle with respect to the second transverse axis and the third vertical axis.

In a second aspect of the present disclosure, a method of retrofitting an oven treatment system provides an enhanced way to monitor the surface temperature of an object being treated. An oven treatment system includes an oven and a conveyor belt. The oven defines a heated transverse tunnel. The conveyor belt travels through the heated tunnel along a first transverse axis. The method includes installing a plurality of sensor modules in an oven processing system. The plurality of sensor modules individually include a housing, a casing, a gas conduit, and a cable. The housing includes a substrate and a thermopile lens. The substrate has a first side and a second side. The first side of the substrate has a thermopile configured to output a first signal indicative of a surface temperature of an object on the conveyor belt relative to a temperature of the substrate. The second side of the substrate has a temperature sensor configured to output a second signal indicative of the temperature of the substrate. The thermopile lens covers the thermopile. The housing defines an opening above the thermopile lens to allow infrared light to enter the opening and reach the thermopile. A gas conduit is coupled to the housing. The cable is coupled to the substrate.

The sensor modules individually have an elongated body that includes a distal end and a proximal end. The distal end includes a housing and an outer shell. The distal end is mounted in a heated tunnel. The proximal end is coupled to a source of pressurized gas and a data acquisition unit outside the heated tunnel. The sensor module and the data acquisition unit together are a measurement system. This design of the sensor module separates the temperature insensitive part (the distal end) from the temperature insensitive part (the electronics of the data acquisition unit). The temperature insensitive end is placed in the heated tunnel and the temperature sensitive end is protected from thermal damage by being placed outside the heated tunnel.

In one embodiment, the sensor module includes a distal end including a housing and an outer shell. The retrofitting method includes installing the distal end within the transverse tunnel adjacent an edge of the conveyor belt. The distal end is mounted such that the thermopile lens is in a generally facing relationship with the upper surface of the conveyor belt.

In a third aspect of the present disclosure, a kit for retrofitting an oven processing system may be used to upgrade the temperature monitoring of the object being processed. An oven treatment system includes an oven and a conveyor belt. The oven defines a heated, laterally extending tunnel. The conveyor belt travels through the heated tunnel along a first transverse axis. The kit includes at least a plurality of sensor modules. The sensor module individually and integrally includes a housing, a casing, a gas conduit, and a cable. The housing includes a substrate and a thermopile lens. The substrate has a first side and a second side. The first side of the substrate has a thermopile configured to output a first signal indicative of a surface temperature of an object on the conveyor belt relative to a temperature of the substrate. The second side of the substrate has a temperature sensor configured to output a second signal indicative of the temperature of the substrate. The thermopile lens covers the thermopile. The housing defines an opening above the thermopile lens to allow infrared light to enter the opening and reach the thermopile. The housing encloses the housing and defines an opening that is aligned with the thermopile lens to allow infrared light from an object to reach the thermopile. A gas conduit is coupled to the housing. The cable is coupled to the substrate.

In one embodiment, the kit may include a data acquisition unit (sensor electronics). A sensor module coupled to the data acquisition unit provides a measurement system. The data acquisition unit is the electronics part of the measurement system and is sensitive to temperature. The sensor modules individually have an elongated body with a distal end and a proximal end. The distal end is temperature insensitive and includes a housing and an outer shell and is configured to be installed within the heated tunnel. The proximal end is configured to attach to temperature sensitive electronics outside the heated tunnel. Thus, the measurement system has a structure whereby the temperature insensitive part can be placed in the heated tunnel and the temperature sensitive part can be placed outside the heated tunnel.

In another embodiment, the sensor module individually comprises a support on which the housing is mounted. The support is contained within the housing. The support member has a long axis, a central axis, and a short axis that are orthogonal to each other. The support member has a first side and a second side. The second side defines a recess on which the housing is mounted. The housing has a first side and a second side facing in the same direction as the first side and the second side of the support, respectively. Electrical leads emerge from the second side of the housing and are routed along the long axis of the support within the recess and are coupled to the cable. The support defines an opening through the first side to the notch and aligned with the thermopile lens. The optical axis of the thermopile lens is typically aligned with openings in the housing, support, and enclosure so that infrared light can pass through the enclosure, support, and enclosure to reach the thermopile lens and then to the thermopile. The support member includes two threaded openings for mounting within the oven. The housing includes two openings that are aligned with the threaded openings. The kit includes a mounting component that attaches to an oven. When the support is mounted to the oven, the screws pass through openings in the housing that cover the threaded openings to attach the support to the mounting member. The screws are tightened to seal the opening in the housing. The housing and threaded opening are typically arranged along a major axis of the support.

In yet another embodiment, the cable passes through at least a portion of the gas conduit between the housing and the data acquisition unit. At least a portion of the gas conduit has the dual function of routing the cable and delivering pressurized gas to the housing. The sensor module may include a joint. The gas conduit includes a first conduit portion between the housing and the fitting and a second conduit portion between the fitting and the pressurized gas source. The cable is separated from the gas delivery conduit at the joint. The joint may be a T-joint. The cable passes directly through the T-joint. The second conduit portion extends from the fitting at a right angle to the first conduit portion. Thus, the cable passes through the first conduit portion but not the second conduit portion.

In yet another embodiment, the kit includes one or more of a source of pressurized gas and a data acquisition unit. The kit may also include software stored on a non-volatile medium for analyzing information from the data acquisition unit. The kit may include other elements that facilitate retrofitting of the oven treatment system, such as mounting accessories and screws.

Drawings

Fig. 1 is a schematic block diagram of an embodiment of an oven treatment system.

Fig. 2 is a schematic diagram depicting an embodiment of a field upgrade kit for retrofitting an oven processing system with a non-contact surface temperature measurement and monitoring system. A "field" upgrade kit may be installed at the site of an existing oven.

FIG. 3A is an isometric illustration of the sensing device, particularly illustrating that the first side of the housing defines an opening that is aligned with the thermopile lens.

Fig. 3B is an isometric illustration of the sensing device with particular emphasis on the second side of the casing through which the leads are exposed.

FIG. 4 is an isometric illustration of a sensing device with a housing looking at an internal substrate with thermopile and thermocouple sensors in ghost.

Fig. 5A is an isometric illustration of a first side of a substrate on which a thermopile sensor is formed.

Fig. 5B is an isometric illustration of a second side of a substrate having a thermocouple disposed thereon.

Fig. 6A is an isometric illustration of a second side of a support on which a sensing device is mounted.

Fig. 6B is an isometric illustration of a first side of a support having an opening aligned with a thermopile lens.

Fig. 7A is an isometric illustration of the distal end of a sensor module with a housing surrounding a support holding a sensing device. The view is toward the second side of the support.

Fig. 7B is an isometric illustration of the distal end of the sensor module with the housing surrounding the support having an opening aligned with the thermopile lens. The airflow into the housing and out of the opening in the housing is also shown. The view is toward the first side of the support.

Fig. 8 is an isometric illustration of the proximal end of a sensor module including a joint where the airflow conduit function and the cable function are separated at a T-joint.

Fig. 9 is an isometric illustration of an embodiment of a sensor module.

Fig. 10 is a perspective view of an oven treatment system with nine mounted sensor modules. In this view, the top cover of the oven is open.

FIG. 11 is an isometric illustration showing the end of a sensor module mounted near a conveyor belt, the object surface temperature being monitored.

FIG. 12 is a schematic of two sensors including a thermocouple and a thermopile.

FIG. 13 is a schematic of two sensors including a thermistor and a thermopile.

Fig. 14 is a flow chart depicting a method of manufacture including installing the retrofit kit of fig. 2 and a method of operating the retrofit oven.

Description of The Preferred Embodiment

Fig. 1 is a schematic block diagram of an embodiment of an oven treatment system 2. The oven treatment system 2 includes a belt oven 4, the belt oven 4 defining a heated tunnel extending laterally therethrough. The conveyor belt 6 passes through (within) the tunnel and is configured to travel laterally through the tunnel to carry objects to be processed by the system 2.

In describing the orientation in this system, X, Y, and Z axes that are perpendicular to each other may be used. The X-axis and Y-axis are generally horizontal transverse axes. The Z-axis is a vertical axis that is generally aligned with a gravity reference. By "generally aligned," we mean that these are aligned within typical mechanical tolerances of manufacturing and positioning of the oven processing system 2. The direction X or first direction is the direction of movement of the conveyor 6 through the oven 4. The direction Y or second direction is a transverse direction transverse to the movement of the conveyor belt. The vertical direction Z may be referred to as a "third direction".

The system 2 comprises a plurality of sensor modules 8, said sensor modules 8 being partially arranged in the tunnel of the oven 4. Sensor modules 8 (otherwise labeled as S1-S4 in FIG. 1) are coupled to one or more data acquisition units 10. The data acquisition unit 10 receives signals from the sensor modules 8 and processes the signals to output signals or data indicative of the surface temperature of objects traveling along the conveyor belt 6. The data acquisition unit 10 is coupled to a controller 12, and the controller 12 analyzes information from the data acquisition unit 10 and displays it on a user interface 14. The data acquisition unit 10 may also be referred to as sensor electronics 10.

The data acquisition unit 10 is located outside the oven 4. The data acquisition unit 10 contains components that are sensitive to temperature and can be damaged within the heated tunnel of the oven 4. The portion of sensor module 8 within oven 4 may be resistant to the temperature of the hottest area of oven 4.

In some embodiments, the controller 12 and the user interface 14 are an integrated unit, such as an embedded computer, a separate computer, or a mobile device. Although only four sensors 8 are shown, the number may vary and may be any practical number. In an exemplary embodiment, the oven 4 has three zones, and each zone has three sensor modules 8, or a total of nine sensor modules. In another embodiment, the oven includes a heating zone and a cooling zone. In yet another embodiment, there are twelve sensor modules 8. In the exemplary embodiment, there are two data acquisition units 10 shown to reduce the length of the sensor module 8. However, in some embodiments, there may be a single data acquisition unit, with all sensors routed to the single data acquisition unit 10.

The system 2 also includes a source of pressurized gas 16, the source of pressurized gas 16 being coupled to the sensor module 8. The pressurized gas source 16 may output air or an inert gas, such as nitrogen. The delivery of gas to the sensor module 8 prevents the accumulation of contaminants on the sensor module 8 that would otherwise reduce the ability to accurately sense the surface temperature.

Fig. 2 depicts an embodiment of a field upgrade kit 18 for providing enhanced temperature sensing capabilities to oven processing system 2. The field upgrade kit provides the components of the measurement system 19. The field upgrade kit includes a sensor module 8, a mounting member 20, a pressurized gas source 16, and a data acquisition unit 10. The sensor module 8 individually includes a sensing device, a housing, a gas conduit, and a cable, which will be discussed in detail below. Mounting member 20 is used to mount the distal end of sensor module 8 within oven 4.

The sensor module 8 has an elongated body with a distal end and a proximal end. The distal end includes a sensing device and a housing. The proximal end includes the end of the gas conduit and the cable. The gas conduit and the cable extend between the distal end and the proximal end. The structure of the sensor module of the elongated body allows for physical isolation of the data acquisition unit 10 (the electronics of the temperature sensitive measurement system) from the remote end (the temperature insensitive sensing device and housing).

Pressurized gas source 16 may take any number of forms. In one embodiment, pressurized gas source 16 includes a regenerative blower for pressurizing and delivering air. In another embodiment, pressurized gas source 16 comprises a nitrogen generator for providing pressurized nitrogen gas to sensor module 8. In still other embodiments, the pressurized gas source may be an inert gas source, such as a pressurized bottle of inert gas such as argon or nitrogen.

Fig. 3A and 3B depict isometric schematic views of sensing device 22 forming part of sensor module 8. In the illustrated embodiment, the sensing device 22 has a cylindrical housing 24 having a first side 26 and a second side 28. The first side 26 defines an opening 30, the opening 30 being aligned with a thermopile lens 32. Four electrical leads 34 emerge from the second side 28. The four leads 34 output signals to be received by the data acquisition unit 10. The cylindrical housing 24 is typically formed of metal.

Fig. 4 depicts the sensing device 22 with the housing 24 in a "ghost image" so that the internal components are visible. Inside the housing 24 is a base plate 36, which base plate 36 is shown separately in isometric view in fig. 5A-5B. The substrate 36 is typically silicon. The substrate 36 has a first side 38 and a second side 40. The first and second sides of the substrate 36 generally correspond to the first and second sides 26, 28, respectively, of the housing 24 and have the same orientation as the first and second sides 26, 28, respectively. A thermopile 42 coupled to the thermopile lead 34TP is formed on the first side 38 of the substrate 36. In operation, the thermopile 42 receives infrared light from the emitting surface through the thermopile lens 32. The thermopile 42 outputs a first signal to the data acquisition unit 10 indicative of the temperature of the emitting surface relative to the temperature of the substrate 36.

A temperature sensor 44 is attached to the second side 40 of the substrate 36. In one embodiment, the temperature sensor 44 is a thermocouple. Thermocouple 44 outputs a second signal indicative of the temperature of substrate 36 to data acquisition unit 10 via thermocouple lead 34 TC. Based on the combination of the thermopile 42 signal and the thermocouple 44 signal, the data acquisition unit 10 and/or controller 12 may determine the temperature of the emitting surface whose infrared radiation is received by the thermopile 42.

Fig. 6A and 6B show opposite views of the mounting of the sensing device 22 on the support 46. In an exemplary embodiment, the support 46 is an aluminum block. The support 46 has a first side 48 and a second side 50. Formed in the second side 50 is a notch 52. The sensing device 22 is mounted in the recess 52 with the second side 28 of the housing 24 facing outwardly of the recess 52. The retaining screw 53 holds the housing 24 in place in the recess 52. The recess 52 extends generally along the major axis of the support 46 to an end 54 of the support 46. The electrical wires 34 from the sensing device 22 extend generally along the notch 52.

Extending from the recess 52 to the first side 48 of the support 46 is a through hole opening 56. The housing 24 is mounted within the recess 52 such that the opening 30 is aligned with the through hole opening 56 to allow infrared light to enter the thermopile lens 32.

The support 46 also includes two threaded holes 58, the two threaded holes 58 being used to mount the support to the mounting member 20. The electrical wires 34, openings 56 and threaded openings 58 are arranged generally along the major axis of the support 46.

Fig. 7A and 7B schematically depict opposite views of a distal end 66 of sensor module 8, distal end 66 of sensor module 8 including support 46 surrounded by outer housing 60, outer housing 60 protecting sensing device 22 from contamination. In an exemplary use, the oven processing system 2 is used to reflow solder on a printed circuit board. Flux from the solder evaporates during reflow and deposits on the bare surface. The housing 60 provides protection from flux deposition.

Fig. 7A depicts a view of the second side 50 of the support 46 within the housing 60. Fig. 7B depicts an opposite view of the first side 48 of the support 46 within the housing 60. The housing 60 defines an opening 62, the opening 62 being aligned with the openings 56, 30 and the thermopile lens 32. Thus, infrared light may pass through the aligned openings and reach the thermopile 42.

The housing 60 also defines two openings 64, the two openings 64 being aligned with the threaded openings 58 of the support 46 to allow the distal end 66 of the sensor module 8 to be mounted to the mounting member 20. Attachment to the mounting member 20 has the effect of sealing the two openings 64.

A coupling 68 attaches and seals the housing 60 to a conduit 70. Conduit 70 delivers pressurized gas 72 from pressurized gas source 16 to housing 60. Gas 72 from the pressurized gas source 16 travels through the conduit 70, into the housing and out the opening 62. The steady gas flow 72 out of the opening 62 prevents contaminants, such as solder flux, from depositing on the thermopile lens 32.

Also shown are openings 74 in the coupler 68 for both functions. The opening 74 allows the wire 34 to enter the conduit 70 as a cable. The openings 74 also allow the gas 72 to flow from the conduit 70 to the housing 60.

Fig. 8 is a schematic view of the proximal end 76 of the sensor module 8. The gas conduit 70 includes a fitting 78, the fitting 78 dividing the gas conduit 70 into two gas transport portions including a first conduit portion 80 coupled to the housing 60 and a second conduit portion 80 coupled to the pressurized gas source 16. In the exemplary embodiment, the fitting 78 is a T-fitting 78, whereby incoming gas arriving from the second conduit portion 82 is diverted 90 degrees and enters the first conduit portion 80 before passing into the housing 60. At the T-joint 78, the conduit portions 80 and 82 are attached to a barb fitting 83.

Also shown is a cable 84, which cable 84 attaches lead 34 to data acquisition unit 10. The cable 84 passes through the first gas conduit 80 to the fitting 78, then on to the conduit 86 and finally to the data acquisition unit 10. The cable 84 includes a four-prong electrical plug 88, the four-prong electrical plug 88 being configured to couple to the data acquisition unit 10. Thus, the cable passes through the first gas conduit portion 80, but not through the second gas conduit portion 82.

Fig. 9 is an exemplary embodiment of sensor module 8. It can be seen that the sensor module 8 is an elongated and largely tubular component. The majority of the length of sensor module 8 is first conduit portion 80, and first conduit portion 80 extends from proximal portion 76 to distal portion 66. The length of the first conduit portion 80 allows for a physical and spatial separation (data acquisition unit) 10 between the temperature sensitive sensor electronics and the temperature insensitive distal portion 66. Distal portion 66 may be placed in a heated tunnel of oven 4, while proximal portion 76 coupled to sensor electronics 10 may be placed outside of the heated tunnel. The first conduit portion 80 may be routed along the edge of the conveyor belt 6 between the mounting location of the distal end 66 and the electronics 10 of the sensor.

Fig. 10 is an isometric illustration of the oven treatment system 2. In the illustrated embodiment, nine sensor modules 8 are used to monitor the surface of an object passing through oven 4. In the illustrated embodiment, grill 4 has a cover 90, which cover 90 is raised to reveal the distal ends 66 of nine sensor modules 8. When the cover 90 is closed, a heated tunnel 92 is defined through which the conveyor belt 6 (not shown here) passes in the first direction X. When nine sensor modules are illustrated, any practical number may be employed. In some ovens 4, there may be 12 or more sensors. Some ovens 4 will have both heating and cooling zones. Various embodiments of the number of ovens and sensor modules 8 are within the scope of the present disclosure.

Fig. 11 is a diagram depicting the upper surface 94 of the printed circuit board 96 being conveyed by the conveyor belt 6. The distal end 66 of the sensor module 8 is shown mounted adjacent the conveyor belt 6.

Two screws 98 are shown, the screws 98 coupling the mounting member 20 to the threaded opening 58. This mounting method provides the dual function of supporting the support 46 above the conveyor belt 6 while sealing the opening 64 in the housing 60. The long axis of the support 46 is mounted substantially aligned with the first direction X of movement of the conveyor belt 6.

The distal end 66 is mounted such that the optical axis of the thermopile lens 32 is generally downward and aligned along the transverse axis Y to receive infrared light from the upper surface 94 of the printed circuit board 96. During operation, gas 71 flows out of opening 62 to prevent solder flux from circuit board 96 from contaminating and fouling thermopile lens 32.

Fig. 12 and 13 depict two different alternatives for sensors 42 and 44. For both alternatives, the sensor 42 is a thermopile. For the embodiment of fig. 12, the sensor 44 is a thermocouple 44. Fig. 13 is an alternative embodiment in which the sensor 44 is a thermistor. The embodiment of fig. 12 is a preferred embodiment because it limits the number of wires that need to be routed along the sensor module 8 to only four wires per module 8. The thermistor of fig. 13 requires six wires per module 8.

Fig. 14 depicts an embodiment of a method of manufacturing 100. A first set of steps 102-106 is for retrofitting the oven processing system 2 with the kit 18. The second set of steps 108 through 114 are used to manufacture circuit boards when the retrofit provides monitoring of the surface temperature of the object being processed.

According to 102, the data acquisition unit 10 is installed on the system 2. According to 104, a source of pressurized gas 16 is installed. According to 106, the sensor module 8 is installed.

For a single sensor module 8: the distal end 66 of the sensor module 8 is mounted in a position to monitor the surface temperature of the treated object. The first conduit portion 80 of the conduit 30 is then routed generally along and towards one side of the conveyor belt 6. The second conduit portion 82 is wired and coupled to the pressurized gas source 16. A cable 84 is routed from the connector 78 and coupled to the data acquisition unit 10.

According to 108, the oven 4 is started and heated to the operating temperature. According to 110, the pressurized gas source 16 is activated such that the gas 72 flows from the pressurized gas 16 source, along the conduit 70, and out the opening 62. According to 112, an object such as a printed circuit board is input into the conveyor belt 6. According to 114, the data acquisition unit and controller captures and analyzes the signals from the sensor 42 to determine the surface temperature of the object being processed.

Different orders of steps are possible. For example, steps 102 and 104 may be performed after partial installation of the sensor module 8. It may be desirable to activate the pressurized gas source 110 prior to starting up the oven 4. Embodiments of any and all possible methods and sensor modules with different sequences of steps are possible unless limited by the claims.

The particular embodiments and applications described above are for illustrative purposes only and do not preclude modifications and variations that are encompassed by the scope of the appended claims.