Patent Publication Number: US-6213118-B1

Title: Oven vent tube

Description:
FIELD OF THE INVENTION 
     This invention relates generally to vent tube assemblies for ovens including commercial cooking ranges. 
     BACKGROUND OF THE INVENTION 
     Currently, oven vent tube assemblies are made in two parts. A flanged tube is inserted through a hole in a wall of the oven chamber from the inside. The flange is secured to the wall with screws. The vent tube with a catalyst therein, is then placed over the flanged tube. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, an integrated design is provided in which the flanged tube is eliminated. The vent tube is fitted over an extruded hole in the wall of the oven chamber. The catalyst is secured in the vent tube preferably by three or more abutments above and below the catalyst. The catalyst may be installed by inserting it into an open end of the vent tube to a position between the two sets of abutments. 
     The abutments may be in the form of flexible tabs lanced from the wall of the vent tube and bent toward the inside of the vent tube. The tabs nearest the open end of the tube may be deformed inwardly before or after insertion of the catalyst, but if deformed inwardly before insertion of the catalyst, the catalyst would have to press against and flex the tabs outwardly during insertion, risking damage to the catalyst. 
     Alternatively, the abutments may be in the form of dimples pressed from the wall of the vent tube toward the inside of the vent tube. The dimples would be flexible. The dimples nearest the open end of the tube maybe formed in the wall of the tube before or after insertion of the catalyst, but, as with the tabs, if formed in the wall of the tube before insertion of the catalyst, the catalyst would have to press against and flex outwardly or flatten the dimples during insertion, risking damage to the catalyst. 
     The present invention is a simple design which eliminates the flanged tube and is easy to manufacture and install. It is also much less expensive than the current design. 
     One object of this invention is to provide an oven vent tube having the foregoing features and capabilities. 
     Another object of the invention is to provide an oven vent tube which is rugged and durable in use, is relatively inexpensive, and can be easily manufactured and installed. 
     These and other objects, features and advantages of the invention will become more apparent as the following description proceeds, especially when considered with the accompanying claims and drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevational view showing an oven and a vent tube extending from the oven chamber, constructed in accordance with the invention. 
     FIG. 2 is an enlarged sectional view of a portion of the vent tube, the catalyst, and a portion of the top wall of the oven. 
     FIG. 3 is an elevational view, with parts in section, of a portion of the vent tube. 
     FIG. 4 is a sectional view taken on the line — 4  in FIG.  3 . 
     FIG. 5 is a view similar to FIG. 3, but shows a modification. 
     FIG. 6 is a sectional view of a prior art construction. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     There is shown in FIGS. 1-4 the drawings an oven  10  which may, for example, be part of a commercial cooking range. The oven  10  has a chamber  12  which is vented by a vent tube assembly  14 . 
     The vent tube assembly  14  includes an elongated open-ended vent tube  16  and a catalyst body  18  within a cylindrical inner end portion  20  of the vent tube. The catalyst body  18  is made of a typical catalyst material, such as a suitable ceramic, and is intended to entrap smoke and generally clear the air before exhausting it to the atmosphere. The catalyst is especially useful during an oven cleaning cycle. 
     The top wall  22  of the oven chamber  12  has a hole  24  defined by an annular, outwardly flared, marginal edge portion  26  providing what is sometimes referred to as an extruded hole. The circular inner end  28  of the vent tube is slipped over the marginal edge portion  26  of the extruded hole preferably with a friction fit. 
     The catalyst body  18  is located within the inner end portion of the vent tube in an operative position by two sets of abutments in the form of flexible tabs  30  and  32  spaced axially from one another. The tabs  30  are arranged in an equal, angularly spaced relationship around the central axis of the inner end portion  20  of the vent tube. The tabs  30 , in their natural, free-state condition, slant radially inwardly in an axially outward direction, that is in a direction away from the oven chamber. 
     The tabs  32  are arranged in equal, angularly spaced relation around the central axis of the inner end portion  20  of the vent tube and are deformed so that, in their natural, free-state condition, slant radially inwardly in an axially inward direction, that is in a direction toward the oven chamber. 
     Preferably there are three or more tabs in each set. The tabs  30  and  32  are lanced from the wall of the vent tube and hence integral with the vent tube. 
     Before the vent tube is fitted over the extruded hole  24 , the catalyst body  18  is installed in the vent tube. The catalyst body is inserted in the inner end  28  of the vent tube. If both sets of tabs are bent inwardly to the positions shown before insertion of the catalyst body, then with some small amount of pressure, the catalyst body will cam past the set of tabs  30  closer to the inner end of the vent tube and into contact with the set of tabs  32 , at which time the tabs  30  snap back so that the catalyst body is captured or trapped between the two sets of tabs in an operative position. After the catalyst body is properly installed, the inner end  28  of the vent tube is placed over the marginal edge portion  26  of the extruded hole as previously described. 
     The catalyst body  18  is typically made of a relatively rigid material and is quite capable of camming past the set of tabs  30  during installation without being damaged. However, if the set of tabs  30  are deformed inwardly to the position shown only after insertion of the catalyst body, the catalyst body would not have to press against and flex the tabs  30  outwardly during insertion, thereby avoiding the possibility of damaging the catalyst body. 
     FIG. 5 shows a modification of the invention in which the abutments for locating the catalyst body in the vent tube are in the form of flexible dimples  40  and  42  spaced axially from one another the same distance as tabs  30  and  32  in the first embodiment. The dimples  40  and  42  are arranged in the same equal, angularly spaced relationship around the central axis of the inner end portion  20  of the vent tube as the flexible tabs  30  and  32  of the first embodiment. The dimples are deformed from the wall of the vent tube so that in their natural, free state condition, they project radially inwardly. 
     Before the vent tube is fitted over the extruded hole  24 , the catalyst body  18  is installed in the vent tube. The catalyst body is inserted in the open end  28  of the vent tube. If both sets of dimples are formed before insertion of the catalyst body, then, with some small amount of pressure, the catalyst will cam past the set of dimples  40  which are closer to inner end of the vent tube and into contact with the set of dimples  42 , at which time the dimples  40  will snap back to their illustrated position such that the catalyst body is captured or trapped between the two sets of dimples in an operative position. 
     However, if the set of dimples  40  are deformed inwardly to the position shown only after insertion of the catalyst body, the catalyst body would not have to press against and flex or flatten the dimples  40  outwardly during insertion, thereby avoiding the possibility of damaging the catalyst body. 
     FIG. 6 shows an example of a prior art construction in which, in addition to the vent tube  16 ′, a flanged tube  50  is required. The flanged tube  50  is inserted through a hole  52  in a wall  54  of the oven chamber  56  from the inside, bringing the radial flange  58  of the tube  50  up against the inner surface of the wall  54 . The flange  58  is secured to the wall  54  with screws  60 . The catalyst body  18  is secured within the vent tube as by adhesive. The inner end of the vent tube is then sleeved over the flanged tube  50 . This is a two-part vent tube assembly consisting of the vent tube and a flanged tube. The flanged tube must be secured to the wall of the oven chamber by screws inserted from inside the oven chamber.