METHOD OF RECORDING IMAGES WITHIN A FURNACE USING A THERMAL IMAGING CAMERA COMPRISING A BORESCOPE

Abstract

A method of recording images within a furnace using a thermal imaging camera comprising a bore scope connected to a digital camera unit is described, comprising the steps of: (a) inserting the borescope into the interior of the furnace, (b) collecting one of more images of the interior of the furnace using the thermal imaging camera with the borescope at a first position, and (c) moving the borescope from the first position to a second position and collecting one or more images of the interior of the furnace as the borescope is moved from the first position to the second position, wherein the borescope movement is guided by means of a guide device comprising a movable borescope mounting, mounted externally on the furnace.

Claims

1-23. (canceled)

24. A method of recording images within a furnace using a thermal imaging camera comprising a borescope connected to a digital camera unit, comprising the steps of: (a) inserting the borescope into the interior of the furnace, (b) collecting one of more images of the interior of the furnace using the thermal imaging camera with the borescope at a first position, and (c) moving the borescope from the first position to a second position and collecting one or more images of the interior of the furnace as the borescope is moved from the first position to the second position, wherein the borescope movement is guided by means of a guide device comprising a movable borescope mounting, mounted externally on the furnace.

25. The method according to claim 24 further comprising a step of (d) combining the images collected in steps (b) and (c) to create a composite image of the interior of the furnace.

26. The method according to claim 24 wherein the movement of the thermal imaging camera from the first position to the second position is manual or driven by a motor.

27. The method according to claim 24 wherein the movable borescope mounting is configured to constrain the movement of the borescope to a single degree of freedom such that the tip of the borescope moves from the first position to the second position along a continuous path.

28. The method according to claim 24 wherein the movable borescope mounting holds the borescope at an angle of between 20 and 90 degrees, to a surface of the furnace on which the guide device is mounted.

29. The method according to claim 24 wherein the borescope is inserted through the movable borescope mounting and into the furnace, the movable borescope mounting holds the borescope at an angle of between 25 and 75 degrees to a surface of the furnace on which the guide device is mounted and provides a circular movement from the first position to the second position, thereby causing the borescope to describe a cone within the furnace as the borescope is moved from the first position to the second position.

30. The method according to claim 24 wherein the furnace is a steam reformer comprising a plurality of tubes containing a steam reforming catalyst.

31. An apparatus for recording images within a furnace, comprising (i) a thermal imaging camera comprising a digital camera unit connected to a borescope and capable of recording a plurality of images, and (ii) a guide device comprising a movable borescope mounting for guiding the borescope, wherein the guide device is configured to be mounted externally on the furnace and to guide the movement of the borescope from a first position to a second position within the furnace.

32. The apparatus according to claim 31 wherein the thermal imaging camera comprises a camera comprising an optical sensor and a rigid borescope comprising an elongated housing having a viewing end and a sensor end, a multi-element relay lens assembly within the elongated housing having at least two optical pieces for directing a real image viewed by the rigid borescope to the camera, the viewing end comprising a lens, wherein the sensor end of the rigid borescope is operatively connected to the camera.

33. The apparatus according to claim 32 wherein the thermal imaging camera comprises an outer housing containing at least a portion of the rigid borescope extending from the viewing end of the borescope and extending towards the sensor end, the outer housing having an outlet at the viewing end of the rigid borescope and an inlet adjacent the sensor end to permit a cooling gas to be passed through the housing.

34. The apparatus according to claim 31 wherein the movable borescope mounting is configured to constrain the movement of the borescope to a single degree of freedom such that the tip of the borescope moves from the first position to the second position along a continuous path.

35. The apparatus according to claim 31 wherein the movable borescope mounting is configured to be rotated.

36. The apparatus according to claim 35 wherein the movable borescope mounting is located within a frame and comprises wheels or bearings that engage with a circular track disposed within the frame.

37. The apparatus according to claim 35 wherein the movable borescope mounting is configured to hold the borescope at an angle of between 20 and 90 degrees to a to a surface of the furnace on which the guide device is to be mounted.

38. The apparatus according to claim 31 wherein the movable borescope mounting has an orifice through which the borescope is inserted, the movable borescope mounting is configured to hold the borescope at an angle of between 25 and 75 degrees to a surface of the furnace on which the guide device is mounted and provide a circular movement from the first position to the second position, thereby causing the borescope to describe a cone within the furnace as the borescope is moved from the first position to the second position.

39. A furnace comprising the apparatus according to claim 31, said furnace having one or more inspection holes or other orifices through which the borescope is inserted.

40. The furnace according to claim 39 wherein the furnace is a steam reformer containing a plurality of catalyst-filled tubes.

41. A device suitable for guiding a borescope of a thermal imaging camera within a furnace, said device comprising a borescope guide device comprising a movable borescope mounting and configured to be mounted on the exterior of the furnace.

42. The device according to claim 41 wherein the movable borescope mounting is configured to constrain the movement of the borescope to a single degree of freedom such that the tip of the borescope moves from the first position to the second position along a continuous path.

43. The device according to claim 41 wherein the movable borescope mounting is configured to be rotated.

44. The guide device according to claim 43 wherein the movable borescope mounting is located within a frame and comprises wheels or bearings that engage with a circular track disposed within the frame.

45. The device according to claim 41 wherein the movable borescope mounting is configured to hold the borescope at an angle of between 20 and 90 degrees to a surface of the furnace on which the device is to be mounted.

46. The device according to claim 42 wherein the movable borescope mounting has an orifice configured to hold the borescope, the movable mounting is configured to hold the borescope at an angle of between 25 and 75 degrees to a surface of the furnace on which the guide device is to be mounted and provide a circular movement from the first position to the second position, thereby causing the borescope to describe a cone within the furnace as the borescope is moved from the first position to the second position.

Description

[0035] The invention will further be described by reference to the following drawings in which:

[0036] FIG. 1 is a side-view depiction of a guided thermal imaging camera in use in a tubular furnace;

[0037] FIG. 2 is a plan drawing of one embodiment of a guide device;

[0038] FIG. 3 is a side drawing of the thermal imaging guide device of FIG. 3;

[0039] FIG. 4 is an oblique depiction of a further embodiment of a of a guide device;

[0040] FIG. 5 is an oblique depiction of a further embodiment of a guide device similar to that in FIGS. 2 and 3 with a thermal imaging camera attached;

[0041] FIG. 6 is a front view of a further embodiment of a guide device with a thermal imaging camera attached; and

[0042] FIG. 7 is a back view of the embodiment of FIG. 6;

[0043] In FIG. 1, a thermal imaging camera, comprising a rigid borescope 10 attached to a digital camera unit 12, is inserted through an inspection port 14 into the interior of a furnace. The inspection port 14 is bounded by the furnace wall 16, which is protected by an internal refractory layer 18. The furnace may be a steam reformer furnace comprising multiple rows of tubes 20 containing steam reforming catalyst. The rows of tubes are heated by a plurality of burners mounted on the interior of the furnace wall (not shown). The thermal imaging camera is mounted in a guide device comprising a frame 22 supporting a movable mounting 24. The frame is mounted on the exterior of the wall 16 by meant of spacing pins 26. The movable mounting 24 is configured to be rotated in the frame 22 about an axis of rotation 28 thereby moving the borescope in a circular path from a first position to a second position adjacent to or overlapping with the first position. The borescope 10 is attached to the movable mounting 24 at an angle of about 45 degrees to the wall 16 of the furnace. The circular movement of the mounting 24 from the first position to the second position therefore causes the borescope 10 to describe a cone 30 as it is moved from the first position to the second position. Arrows are included to depict the rotation of the borescope 10 and camera unit 12. As a result of using the guide device, the field of view 32 of the borescope 10 moves in a controlled manner within the steam reformer furnace, that enhances the capture of thermal image data.

[0044] In FIGS. 2, 3 and 4 a guide device is depicted comprising a frame 22 in the form of a shaped metal plate supporting a movable mounting 24. The frame comprises upper left and right horns 42, 44, each supporting a spacing pin 26 extending from the back of the frame. Beneath the horns, the frame comprises a circular track 44, fixed centrally within the frame, that provides a circular space in which the movable mounting 24 is located. The diameter of the circular track 44 is about 30 cm. Beneath the track 44, the frame further comprises a clamp portion 46 extending vertically downwards that comprises a screw clamping device 48 for clamping the guide device to an exterior wall of a furnace. The movable mounting is a four-lobed structure comprising freely rotating wheels (FIG. 4, 54) mounted in each of the lobes that run on the track 44 and enable the movable mounting to rotate within the frame. The movable mounting further comprises a tubular borescope mounting 50 that passes through the movable mounting. The borescope mounting 50 is positioned on a line between two of the wheels, and equidistant between the wheels. The longitudinal axis of the borescope mounting 50 is at an angle of about 45 degrees to the frame. The borescope mounting 50 has a diameter large enough to enable insertion of a borescope therethrough. A fixing collar 52 is present on the borescope mounting 50 to lock the borescope in place. In FIG. 4, a handle 60 is mounted between the horns 40, 42, to assist with positioning of the guide device on the furnace wall before and during its use.

[0045] FIG. 5 depicts apparatus comprising a thermal imaging camera comprising a borescope 10 and a camera unit 12 attached to a guide device similar to that in FIGS. 2 and 3 in which the borescope 10 is inserted through the borescope mounting 50.

[0046] In FIGS. 6 and 7 a guide device is depicted comprising a frame 22 in the form of a shaped metal plate supporting a movable mounting 24. The frame has upper left and right horns 42, 44, each supporting magnet blocks (FIG. 7, 80) extending from the back of the frame. Beneath the horns, the frame comprises a circular track 44, fixed centrally within the frame, that provides a circular space in which the movable mounting 24 is located. Beneath the track 44, the frame further comprises a support member (FIG. 7, 84) extending perpendicular to the frame 22 for supporting the apparatus on the edge of an opening in the furnace wall. The movable mounting is a lobed structure comprising freely rotating wheels mounted in each of the lobes that run on the track 44 and enable the movable mounting to rotate within the circular track 44 within the frame 22. The movable mounting further comprises a tubular borescope mounting (FIG. 6, 50) that passes through the movable mounting 24. The borescope mounting 50 is positioned on a line between two of the wheels, and equidistant between the wheels. The longitudinal axis of the borescope mounting 50 is at an angle of about 45 degrees to the frame. The borescope mounting 50 has a diameter large enough to enable insertion of a borescope 10 therethrough. A fixing collar (FIG. 6, 52) is present on the borescope mounting 50 to lock the borescope in place. The entire device is supported on two legs 70 that extend downwardly from the sides of the frame 22. The track 44 further comprises a scale 72 that indicates by means of a pointer 74 attached to the movable guide 24, the degree of rotation of the borescope 10. The viewing end of the borescope comprises a lens 90 through which the images may be captures during use.

[0047] In use, the guide device is mounted onto the exterior wall of the furnace over a suitable orifice such as an inspection port. The clamp 48 or magnets 80 are used to attach the guide device to the wall and help to hold it in the desired position. A thermal imaging camera comprising a borescope 10 and a digital camera unit 12 is attached to the guide device by inserting the borescope 10 through the borescope mounting 50 into the interior of the furnace and fixing it in place using the collar 52. One or more images are recorded using the thermal imaging camera at a first position. The movable mounting 24 is then rotated manually within the frame 22 causing the camera 12 and borescope 10 to rotate from the first position to a second position, which may be adjacent to or overlap with the first position. The angle at which the borescope is mounted results in the borescope describing a cone as the mounting 24 is rotated from the first position to the second position. During the rotation, the thermal imaging camera records multiple additional images of the interior of the furnace.

[0048] The image recorded at the first position is combined with the multiple images recorded as the borescope and attached camera are rotated to create a composite image of the interior of the furnace, from which temperature data for the tube surfaces may be obtained.

[0049] For the embodiments of the guide devices shown in FIGS. 1-7, all the images share a common fixed point, and each image is an approximate rotation of the previous image about this point.