Abstract:
An illumination module comprises a ring-shaped mounting member having an axially extending viewing passage and an L-shaped radiation guide including a radiation entry end for communication with an external radiation source and a radiation exit end provided with a fused glass window for insertion within a process vessel or pipeline. The radiation guide extends through a radial guide hole in the mounting member and bends to run axially along the passage of the mounting member in close proximity to the wall of the passage so as to minimize blockage of available viewing area through the passage. The illumination module can be clamped between a sight glass or camera viewing unit and the flange of a nozzle port, or between segments of a pipeline near a viewing window of the pipeline, to form an illumination and viewing assembly. A coarse flow duct system in the mounting member, and a fine flow duct system in the mounting member and radiation guide, enable delivery of cleaning fluid to a sight glass or camera unit, and to the fused glass window of the radiation guide, respectively.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to devices for observing the interior contents of a vessel or process pipeline, and more particularly to a module for introducing illuminating radiation into the vessel or pipeline in an efficient manner without substantially interfering with the opportunity to view the illuminated contents.  
           [0003]    2. Description of the Related Art  
           [0004]    It is known to use various devices for direct or remote viewing of the interior of a pressure vessel, reaction vessel, process pipeline, or the like. A simple device for this purpose is a transparent viewing window provided in a wall of the vessel or pipeline. By looking through this window, an operator can observe liquid levels, color changes, and other visually determinable factors taking place within the vessel or pipe. Several of these viewing windows are disclosed, for example, in U.S. Pat. Nos. 2,744,487; 3,299,851; 3,837,226; and 4,245,566. One problem associated with these viewing windows is that a lack of illumination hinders observation of the contents.  
           [0005]    To overcome the problem of illumination, Thomas Canty invented a light pipeline device as described in U.S. Pat. No. 4,746,178 for illuminating the interior of a pressure vessel. The device comprises a housing containing a fiber optic rod running straight from an external light source to a fused glass, laminated barrier disc. The unit is securely mounted on the vessel apart from a separate viewing window, with the barrier disc being arranged adjacent the interior of the vessel, whereby source light is transmitted to illuminate the vessel contents. Although this advancement significantly helps with viewing, it requires another separate aperture through the vessel wall for illumination in addition to the aperture provided for viewing. Also, illuminating through the fused glass barrier disc creates unwanted reflections that hinder viewed image quality.  
           [0006]    It is also known, as a matter of common practice, to simply position a light source near a viewing window such that both illumination and viewing take place through the same window in the vessel. This approach is less than ideal because the light source blocks a significant portion of the viewing window, leaving only a small portion of the window for viewing, and illumination light is reflected by the viewing window such that it interferes with viewing instead of illuminating the contents of the vessel as intended.  
           [0007]    Combination illumination and camera viewing units are known in the prior art, for example from U.S. Pat. No. 5,230,556 to Canty et al. Units of this type include a centrally located camera for automatic viewing through a sight glass and a light guide delivering light through the sight glass adjacent the camera lens for illumination along an axis substantially parallel to the camera lens axis. This arrangement does not allow an on-site operator to look through the sight glass to view interior contents because the sight glass is blocked by the camera and light guide. Moreover, in the apparatus described in the &#39;556 patent, the light guide cannot be inserted beyond the sight glass into the vessel, and illumination energy per unit volume dissipates quickly with distance into the vessel. Consequently, the effectiveness of external illumination units of the prior art is particularly diminished in those situations where the sight glass is positioned on a nozzle entry which extends out from the interior wall surface of the vessel by several inches.  
           [0008]    Another problem associated with viewing windows of the prior art is that an internal surface of the viewing window can become clouded or blocked by process constituents coming into contact therewith. This problem is exacerbated where heat from an illumination source causes the internal contents to bake onto the viewing window.  
         BRIEF SUMMARY OF THE INVENTION  
         [0009]    It is therefore an object of the present invention to enable introduction of cool illumination into the process and allow for maximum transmission of illuminating radiation into the interior of the vessel for viewing purposes.  
           [0010]    It is another object of the present invention to provide a modular means of cool illumination that can be mounted in combination with a sealed transparent or translucent sight glass without blocking a substantial portion of the sight glass.  
           [0011]    It is a further object of the present invention to provide a modular means of cool illumination that can be mounted in combination with a sealed camera unit or other radiation detector unit without blocking a substantial portion of the field of view of the camera.  
           [0012]    It is a further object of the present invention to provide a modular illumination device that can be combined with either a sight glass or an automatic viewing unit as desired.  
           [0013]    It is a further object of the present invention to provide an insertable means of illumination that will eliminate reflection into the operator&#39;s eyes or camera lens, thereby maximizing viewing capacity and accuracy.  
           [0014]    It is a further object of the present invention to provide an insertable means of illumination that can be installed at a nozzle port to effectively illuminate process constituents at a location spaced inwardly from the nozzle port.  
           [0015]    It is a further object of the present invention to provide an illumination module having means for enabling periodic cleaning of a viewing window adjacent to the illumination module while the process vessel is operational.  
           [0016]    It is a further object of the present invention to provide an illumination module having means for enabling periodic cleaning of a radiation exit end of an insertable radiation guide of the module for maintaining a high level of illumination.  
           [0017]    It is a further object of the present invention to provide for non-axial illumination of a process for viewing through a separate viewing device.  
           [0018]    In furtherance of these and other objects, an illumination module formed in accordance with a preferred embodiment of the present invention generally comprises a ring-shaped mounting member having an axially extending viewing passage therethrough, and an L-shaped radiation guide having a radiation entry end for communication with an external radiation source and a radiation exit end provided with a fused glass window for insertion within a vessel or pipeline containing process constituents. The radiation guide is arranged such that it extends through a radial guide hole in the mounting member and bends to run axially along the passage of the mounting member in close proximity to the wall of the passage so as to leave a majority of the cross-sectional area of the passage unblocked for viewing therethrough.  
           [0019]    The illumination module can be clamped between a sight glass or camera viewing unit and the flange of a nozzle port, or between segments of a pipeline near a viewing window of the pipeline, to form an illumination and viewing assembly.  
           [0020]    In a preferred embodiment, the mounting member includes a coarse flow duct system for enabling delivery of cleaning fluid to a sight glass or camera unit mounted adjacent thereto, and the mounting member shares a fine flow duct system with an outer housing of the radiation guide for enabling delivery of cleaning fluid to the fused glass window at the radiation exit end of the guide.  
           [0021]    The illumination module of the present invention, and the preferred features thereof, can be used separately or in any combination with other modular accessories beyond a sight glass or camera viewing unit. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]    The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the preferred embodiment taken with the accompanying drawing figures, in which:  
         [0023]    [0023]FIG. 1 is an exploded perspective view showing an illumination and viewing assembly incorporating an illumination module formed in accordance with a preferred embodiment of the present invention aligned with a sight glass;  
         [0024]    [0024]FIG. 2 is an end view of an illumination module similar to that shown in FIG. 1;  
         [0025]    [0025]FIG. 3 is a cross-sectional view of the illumination module shown in FIG. 2;  
         [0026]    [0026]FIG. 4 is an enlarged cross-sectional view of an exit end of a radiation guide of an illumination module formed in accordance with the present invention;  
         [0027]    [0027]FIG. 5 is a side elevational view showing an illumination and viewing assembly incorporating an illumination module of the present invention inserted in a process pipeline for directing illuminating radiation orthogonal to a viewing axis of a viewing window in the pipeline; and  
         [0028]    [0028]FIG. 6 is a side elevational view showing an illumination and viewing assembly incorporating an illumination module of the present invention aligned with a camera viewing unit. The camera can be oriented in an infinite number of ways. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0029]    For purposes of describing and claiming the present invention, the term “radiation guide” is intended to encompass, without limitation, any device used to constrain or guide radiation along a defined path without significant energy loss, including optical wave guides, light pipes, fiber optic bundles, and the like. Also for purposes of describing and claiming the present invention, the term “radiation detector” is intended to encompass, without limitation, any device used to sense radiated energy, including photosensitive elements and arrays responding to infra-red light, visible light, and ultra-violet light; ultrasound imaging devices; radar sensors; and nuclear radiation sensors. The term “illuminate,” as used herein in its various forms, refers to application of radiation in any form, as opposed to just light, to a subject. Similarly, the term “view,” as used herein in its various forms, refers to detection of radiation generally, and is not limited to detection of light.  
         [0030]    Reference is made initially to FIG. 1 of the drawings, wherein a vessel  2  is shown as including a nozzle port  4  extending outward from a wall of the vessel. An illumination module  20  formed in accordance with the present invention is mounted between a distal flange  6  of nozzle port  4  and a sight glass  8  such that the nozzle port, illumination module and sight glass are in axial alignment with each other. Illumination module  20  delivers illuminating radiation from one or more radiation sources  3  to the internal contents of vessel  2 , thereby enabling observation of a process, such as a chemical reaction, taking place within vessel  2 . In a preferred mounting arrangement, a first sealing gasket  10  is located between opposed surfaces of flange  6  and illumination module  20 , and a second sealing gasket  12  is located between opposed surfaces of the illumination module and sight glass  8 . Illumination module  20  and sight glass  8  are clamped in place by a retainer flange  14  and a series of angularly spaced bolts  16  extending through aligned bolt holes in the retainer flange and nozzle port flange to mate with corresponding nuts  18 .  
         [0031]    It is also possible to mount illumination module  20  in combination with a “Quickport Closure Device” as shown and described in commonly-owned U.S. Pat. No. 5,141,125 issued Aug. 25, 1992, which patent is hereby incorporated in the present specification by reference. In such an arrangement, illumination module  20  can be located between a sliding door of the Quickport Closure Device and the nozzle port flange.  
         [0032]    Referring also now to FIGS. 2 and 3, it will be seen that illumination module  20  generally comprises a mounting member  22  that is preferably ring-shaped, and one or more radiation guides  24 . Mounting member  22 , which can be any suitable shape, includes a leading end  26  intended to be mounted proximate to nozzle port flange  6  and a trailing end  28  in sealed adjacency to sight glass  8 . Leading end  26  and trailing end  28  are connected by an outer surface  30 . A passage  32  extends through mounting member  22  from leading end  26  to trailing end  28 , and one or more guide holes  34  extend radially through mounting member  22  from outer surface  30  to passage  32  for communication with the passage. In a preferred embodiment, mounting member  22  is cylindrical in shape, and leading end  26  and trailing end  28  are parallel planar surfaces normal to an axial direction of the mounting member so that the illumination module can be installed easily between segments of a pipeline, as will be described below.  
         [0033]    As will be appreciated from examining FIG. 2, the cross-sectional area of passage  32  that is unblocked by radiation guide  24  is greater than the cross-sectional area of passage  32  that is blocked by radiation guide  24  to facilitate viewing through the passage. This is also a preferred condition where more than one radiation guide  24  is provided, as shown for example in FIG. 1. The radiation guide can be at any angle including the 90 degrees as shown.  
         [0034]    Radiation guides  24  each comprise a tubular housing  36  defining a radiation entry end  38  for communication with a radiation source  3  and terminating at a radiation exit end  40 . Within housing is a light pipe  41  or other suitable means for guiding source radiation. Housing  36 , which is preferably stainless steel to withstand the effects of process chemicals, can be made of selected parts welded end-to-end to form a ninety-degree bend in the radiation guide path. Other materials resistant to corrosion can be used, including but not limited to HASTELLOY®, glass, TEFLON®, and the like. In the preferred embodiment described presently, housing  36  includes a light pipe fitting  42 , a first extension tube  44  welded onto the light pipe fitting  42 , a short radius ninety-degree elbow  46  welded to first extension tube  44 , a second extension tube  48  welded to elbow  46 , and a terminal fitting  50  welded to second extension  48 . A centering guide  52  is welded into terminal fitting  50 . A procedure for assembling radiation guide  24  and installing it in mounting member  22  includes spot welding centering guide  52  into terminal fitting  50 , welding second extension tube  48  to terminal fitting  50 , welding second extension tube  48  to elbow  46 , welding elbow  46  to first extension tube  44 , moving the resulting subassembly into passage  32  and inserting first extension tube  44  into guide hole  34  until the subassembly is as close as allowed to the inner wall of mounting member  22 , welding the subassembly in place using a fillet weld between the subassembly and inner wall, and then pressing and welding light pipe fitting  42  onto first extension tube  44 .  
         [0035]    Beginning at radiation entry end  38 , radiation guide  24  is arranged to extends through guide hole  34  of mounting member  22  into passage  32  and along the passage in the direction of leading end  26  until the radiation guide terminates at radiation exit end. As best seen in the enlarged view of FIG. 4, radiation exit end  40  includes a glass window  54  fused to housing  36 , and more specifically to terminal fitting  50  of housing  36 . Window  54  is formed of a material that transmits the particular source radiation and preferably exhibits strength and corrosion resistance. By way of example, fused glass window  54  can be made of borosilicate glass, quartz glass, acrylics, optical grade polymers, and similar transparent or translucent materials. Each fused glass window  54  is individually fused at high temperature and pressure in terminal fitting  50  to maintain a hermetic seal between the interior of vessel  2  and the interior of housing  36 . The fusing process followed in the present invention is similar to that process described in  Glass Engineering Handbook, Third Edition , Chapter 5, (1984) Library of Congress ISBN 0-07-044823-X by G. W. McLellan and E. B. Shand. Fused glass window  54  is depicted as a plano-plano lens in FIG. 4, however other lens configurations can be used depending upon the application. For example, if divergence of an illumination beam of source radiation is desired, fused glass window  54  can be a biconcave, plano-concave, or negative meniscus lens. Conversely, if convergence of an illumination beam of source radiation is desired, fused glass window  54  can be a biconvex, plano-convex, or positive meniscus lens.  
         [0036]    Illumination module  20  preferably includes a coarse flow duct system  60  communicating with at least one spray port  62  directed at said sight glass  8 , whereby fluid from a fluid source (not shown) can be delivered for cleaning the sight glass. In the embodiment shown in FIGS. 2 and 3, coarse flow duct system  60  includes a fluid entry port  64  opening radially through outer surface  30  of mounting member  22  and communicating with an internal, substantially circumferential delivery channel  66  in the mounting member. In turn, the delivery channel  66  communicates with spray ports  62  which are spaced angularly about a central axis of passage  32  and directed obliquely at the internal surface of sight glass  8 .  
         [0037]    Referring now to FIGS. 2 and 4, a fine flow duct system  70  is preferably provided through mounting member  22  and radiation guide housing  36  for flow communication with spray ports  72  directed at fused glass window  54 , whereby fluid from a fluid source (not shown) can be delivered for cleaning the exposed surface of the fused glass window. The fine flow duct system  70  includes a fluid entry port  74  opening radially through outer surface  30  of mounting member  22  and bending to communicate with fine internal delivery channels  76  running within the walls of housing  36  to reach spray ports  72 .  
         [0038]    As illustrated in FIG. 5, illumination module  20  of the present invention can be installed in a process pipeline  80  for directing illuminating radiation in any direction in relation to a viewing axis of an existing viewing window  82  in the pipeline, or in some other direction or angle relative to the viewing axis. The non-axial illumination is particularly useful for observing fluid-fluid and particle-fluid process interfaces. As mentioned above, the leading end  26  and trailing end  28  of mounting member  22  are parallel planar surfaces, such that pipeline segments  80 A and  80 B connected via mounting member  22  can remain in alignment along a straight pipeline axis. In the assembly shown, mounting member  22  is clamped between opposing end flanges  81 A and  81 B of pipeline segments  80 A and  80 B using a plurality of nut and bolt connections  84  between the end flanges, with a pair of sealing gaskets  86  being positioned between the leading end  26  of mounting member  22  and end flange  81 A and between the trailing end  28  of mounting member  22  and end flange  81 B, respectively. It will be realized that a camera unit or other radiation detector can be substituted for viewing window  82 .  
         [0039]    [0039]FIG. 6 shows a further illumination and viewing assembly incorporating illumination module  20  of the present invention. The assembly comprises a radiation detector in the form of a camera unit  90  mounted adjacent to trailing end  28  of mounting member  22  such that a field of view of camera lens  92  is through an unblocked cross-sectional area of passage  32 . In the assembly of FIG. 6, mounting member  22  is clamped between a nozzle flange  6  and an abutment flange  94  of camera unit  90  by a retainer flange  96  arranged about the camera unit housing and a plurality of nut and bolt connections  95  acting between the nozzle flange and the retainer flange. Sealing gaskets  98  are positioned between the leading end  26  of mounting member  22  and nozzle flange  6 , and between the trailing end  28  of mounting member  22  and abutment flange  94  of camera unit  90 . Camera unit  90  can be of a type described in commonly owned U.S. Pat. No. 4,977,418, which patent is hereby incorporated by reference into the present specification. Of course, alternative radiation detection units can be used, depending upon the type of illuminating radiation involved.  
         [0040]    Those familiar with the present art will realize that there exists an infinite number of orientations at which camera unit  90 , or another radiation detector, can be installed with respect to a process pipeline or vessel. Therefore, while the drawings show a substantially ninety-degree bend in radiation guides  24 , other bends and additional directional shifts can be provided in a radiation guide  24  as it extends along passage  32 .  
         [0041]    While clamping means are disclosed for installing or mounting the assemblies of FIGS. 5 and 6 in a pipeline or on a vessel, it will be realized that many alternative means and configurations for installing or mounting exist, including but not limited to other flanged connections, direct threaded connections wherein mating threads are provided, TRI-CLOVER® connections, and the like.