High temperature control damper with sealing flange

Abstract: Two damper blades (26,28) are mounted between high temperature bearings (34,36,44,46) and rotate in an insulated housing (20). The inner ends of the damper engage in a ship-lap joint (120), and the outer ends (26a,28a) of the damper engage against sealing flanges (104,106). The damper (10) is intended to be used in an Air Flotation Dryer with Built-In Afterburner or any other high temperature environment.

Description: 1. Field of the Invention - The present invention pertains to a control damper, and more particularly, to a high temperature control damper with a sealing flange such as for use in an Air Flotation Dryer with Built-In Afterburner. 2. Description of the Prior Art -Prior art damper devices experienced excessive hot air leakage from high temperature chambers due to poor sealing of damper plates, with respect to each other, and also with respect to the surrounding duct casing because of the thermal metal expansion. Difficulties were also encountered where the integrity of the welds holding the damper blades to the corresponding drive shafts would be violated by rapidly changing temperatures occurring within and adjacent to the control damper environment. The present invention overcomes the disadvantages of the prior art by providing a stainless steel control damper with thermal expansion compensation in the sealing devices and also by providing damper blades which are securely pinned to the slotted drive shafts. The general purpose of the present invention is to provide a high temperature control damper such as for an Air Flotation Dryer with Built-In Afterburner. The high temperature control damper of the present invention is as defined in claim 1. Claim 1 is delimited over US-A-4932437 as closest prior art. One significant aspect and feature of the present invention is a control damper for use in high temperature environments exceeding 870°C (1600°F). Having thus described one embodiment of the present invention, it is the principal object hereof to provide a control damper for use in high temperature environments. One object of the present invention is a high temperature damper for use in an Air Flotation Dryer with Built-In Afterburner. Other objects of the present invention and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, in which like reference numerals designate like parts throughout the Figures thereof and wherein: Fig. 1 illustrates a perspective view of a high temperature control damper according to the present invention; Fig. 2 illustrates a front view of the high temperature control damper; Fig. 3 illustrates a cross-sectional view along line 3-3 of Fig. 2; Fig. 4 illustrates a bottom view of the high temperature control damper; Fig. 5 illustrates a part sectional (taken on line 5-5) part elevational view of a high temperature bearing and packing gland; and Fig. 6 illustrates a cross-sectional view of a slotted stub shaft along line 6-6 of Fig. 2. FIG. 1 illustrates a perspective view of a high temperature control damper 10, according to the present invention, for use in a high temperature environment. Reference to FIG. 2, as well as the other FIGS., is useful in understanding the present invention. Stainless steel channel members 12, 14, 16 and 18 form a rectangular housing 20 for mounting of the components therein. The rectangular housing 20 also includes a plurality of holes 22a-22n and 24a-24n in the channel sides to facilitate mounting of the high temperature control damper 10 in a duct work system, such as an Air Flotation Dryer with Built-In Afterburner. A pair of stainless steel damper blades 26 and 28 mount centrally, and are suspended within the interior of the rectangular housing 20 to control the flow of hot air through the interior cavity 30 bounded by the channels 12-18. An upper bracket 32 secures on the channel member 18. High temperature bearings 34 and 36 secure to the upper bracket 32. Stainless steel stub shafts 38 and 40 align in the high temperature bearings 34 and 36, respectively, and extend through the channel member 18. The upper edge of damper blade 26 secures to the lower end of the stub shaft 38, and the upper edge of the damper blade 28 secures to the lower end of the stub shaft 40 as later described in detail. The lower edges of the damper blades 26 and 28 secure in a similar fashion. A lower bracket 42 secures to the channel member 14. High temperature bearings 44 and 46 secure to the lower bracket 42 as illustrated in FIG. 2. A stainless steel stub shaft 48 and a stainless steel stub shaft 50 extend through the channel member 14 to align in the high temperature bearings 44 and 46. The lower edge of the damper blade 26 secures to the upper end of the stainless steel stub shaft 48, and the lower edge of the damper blade 28 secures to the upper end of the stainless steel stub shaft 50 as later described in detail. Fiber insulation blanket material 52a-52n lines the interior walls of the rectangular housing 20 as later described in detail. Horizontally aligned upper and lower ceramic fiber insulation boards 54 and 56 and vertically aligned left and right ceramic insulation boards 58 and 60, respectively, align inwardly from the fiber insulation blanket material 52a-52n. The fiber insulation blanket material 52a-52n and the ceramic fiber insulation boards 54-60 extend from the front side to the back side. FIG. 2 illustrates a front view of the high temperature control damper 10 where all numerals correspond to those elements previously described. High temperature bearings 34, 36, 44 and 46 secure to the upper bracket 32 and lower bracket 42, respectively, with nut and bolt hardware 62a-62n. Stub shafts 38 and 40 secure within the high temperature bearings 34 and 36 by collar clamps 64, 66, 68 and 70. The stub shaft 48 secures within the high temperature bearing 44 by a collar clamp 72 and a link arm assembly 74. The stub shaft 50 secures within the high temperature bearing 46 by a collar clamp 76 and a link arm assembly 78. The stub shafts 38, 40, 48 and 50 each pass through respective packing glands 80, 82, 84 and 86, respective channel members 18 and 14, respective fiber insulation blankets 52b and 52k, and respective ceramic fiber insulation boards 54 and 56. The stub shafts 38, 40, 48 and 50 are slotted at their inboard ends to accommodate their respective damper blades 26 and 28. Pins 88 and 90 pass through both sides of the slotted inboard ends of the shafts 48 and 50, and through the lower ends of the damper blades 26 and 28 to secure the respective members to each other in a stationary fashion. The upper ends of the damper blades 26 and 28 are secured in a similar manner. Stub shafts 38 and 40 feature slotted holes 92a, 92b and 94a and 94b common to the shafts 92 and 94. Pin 96 passes through the slotted hole 92a and 92b of the stub shaft 38 and also through a hole 100 in the upper end of the damper blade 26. Pin 98 passes through the slotted hole 94a and 94b of the stub shaft 40 and also through a hole 102 in the upper end of the damper blade 28. The damper blades 26 and 28 heat and expand during damper operation. The upper end portions of the damper blades 26 and 28 move within and are slidingly engaged by the slotted ends of the stub shafts 38 and 40. The pins 96 and 98 are allowed to ride in a nonbinding manner in the slotted holes 92a-92b and 94a-94b, respectively, as the lengths of the damper blades 26 and 28 vary according to the temperature of the air passing through the high temperature control damper 10. Support for the upper ends of the damper blades 26 and 28 is maintained by the slotted end, and the pin arrangement securing the damper blades 26 and 28 to their respective stub shafts 38 and 40. A cross-sectional view of the stub shaft 38 is provided in FIG. 6. A U-shaped high temperature stainless steel sealing flange 104 with right angled ends secures between the ceramic fiber insulation boards 54 and 56 and adjacent to the ceramic fiber insulation board 58. A corresponding and opposing U-shaped high temperature stainless steel sealing flange 106 with right angled ends secures between the ceramic fiber insulation board 54 and 56 and adjacent to the ceramic fiber insulation board 60. Another high temperature stainless steel sealing flange 108 secures to the ceramic fiber insulation board 54, and a high temperature stainless steel sealing flange 110 secures to the ceramic fiber insulation board 56. The damper blades 26 and 28 are rotationally positioned against the sealing flanges 104-110. Stub shaft 50 is rotatable to position the damper blade 28. Link arm assemblies 74 and 78 cause the stub shaft 48 to be counter rotated to position the damper blade 26. The damper blades 26 and 28 are moved in unison by predetermined proportional amounts to provide air to flow between the inner edges of the damper blades 26 and 28 and around the outer edges of the damper plates 26 and 28, and the area between the outboard outer edges 26a, 28a of the damper plates 26 and 28 and the ceramic fiber insulation board 58 and 60. The damper blades 26 and 28 seal against the sealing flanges 104-110 when desired by rotation of the stub shaft 50. The inboard edges of damper blades 26 and 28 have a ship-lap sealing joint 120 for thermal expansion compensation. This ship-lap seal is illustrated and described in FIG. 3. Bolts 112a-112b and 114a-114b secure the ceramic fiber insulation board 58 and 60, respectively, to channel members 12 and 16. FIG. 3 illustrates a cross-sectional view along line 3-3 of FIG. 2 where all numerals correspond to those elements previously described. Particularly illustrated are the damper blades 26 and 28 against the sealing flanges 104, 106 and 108. Damper blades 26 and 28 have dados 116 and 118 which form a ship-lap joint 120. As the temperature of the damper blades 26 and 28 changes upwardly or downwardly, the widths of the damper blades 26 and 28 increase or decrease accordingly. A slip seal at the ship-lap joint 120 is maintained due to the fact that the dado surfaces 116 and 118 slide horizontally and still maintain contact throughout thermal expansion. The outboard ends 26a and 28a of the damper blades 26 and 28 are of proper length and spacing with respect to the vertical portions 104a and 106a to maintain a good seal with the horizontal portions 104b and 106b of the sealing flanges 104 and 106 during thermal activity. Direction of rotation of the damper blades 26 and 28 are indicated by arrows 122 and 124. FIG. 4 illustrates a bottom view of the high temperature control damper 10 where all numerals correspond to those elements previously described. Illustrated in particular is the linkage between the stub shafts 48 and 50. A linkage bar 126 secures to link arm assemblies 74 and 78 of stub shafts 48 and 50, respectively, with fasteners 128 and 130. When the stub shaft 50 is rotated, stub shaft 48 is counter rotated via the link arm assembly 78, linkage bar 126 and link arm assembly 74 to position the damper blades as previously described. A support 132 for the lower bracket 42 is illustrated beneath the lower bracket 42. A corresponding support 134 is also illustrated in FIG. 2. FIG. 5 illustrates a view of a high temperature bearing 34 and high temperature packing gland 80 along line 5-5 of FIG. 2 where all numerals correspond to those elements previously described. High temperature fiber wicking 136 is held in place by a follower plate assembly 138. Studs 140 and 142 secure the follower plate assembly 138 to the channel member 18. FIG. 6 illustrates a cross-sectional view of the slotted stub shaft 38 along line 6-6 of FIG. 2 where all numerals correspond to those elements previously described. Slot 39 aligns with a diameter of the stub shaft 38, and is a clearance fit in the stub shaft so as to slide relative thereto, (a) to compensate for heat expansion of the damper blade 26 and the stub shaft 38, and (b) to preclude binding between the damper blade 26 and the stub shaft 38. The pin 96 extends through slotted hole 92a, hole 41 in the damper blade 26, and hole 92b and is secured thereto by a fastener 43 in the end of the pin 96. The slotted holes 92a, 92b and 41 are also dimensioned to compensate for heat expansion of the damper blade 26, the stub shaft 38 and the pin 96. The clearances between the members of FIG. 6 are illustrated exaggerated for purposes of clarity. Pin 98 affixes the damper blade 28 to the stub shaft 40 in a like and similar manner. The damper blades 26 and 28 rotate in high temperature bearings 34, 36, 44 and 46 as illustrated in FIG. 1 about their respective axes until their inboard edges engage the inner ends in a ship-lap joint 120 configuration as illustrated in FIG. 3. The damper blades are pinned to their respective shafts to provide mechanical integrity. Sealing flanges 104 and 106 engage the outer edges of the dampers. The damper blades are particularly suited for use in an Air Flotation Dryer with Built-In Afterburner.

Claims: A high temperature control damper (10) comprising: a housing (20) including insulation means (52a-52n) about said housing; spaced opposing high temperature bearings (34, 44) secured to opposite sides (18,19) of said housing; first and second shafts (38,48) extending between said bearings; a damper (26) secured to each of said shafts for rotation therewith; sealing means (104, 106, 108, 110) between edges of said damper and said housing; and linkage means (74, 126) connected to one (48) of said first and second shafts for rotation of said dampers; characterised in that said first and second shafts (38, 48) are slotted at their inboard ends (at 39); and in that said damper is secured with a clearance fit in that slot (39) of said second shaft (48) to slide relative thereto. A high temperature control damper according to claim 1, wherein said damper is fixedly secured in the slot of said first shaft (38). A high temperature control damper according to claim 1 or 2, wherein said sealing means at one of said edges of the damper include a second said damper (28) mounted on third (40) and fourth (50) shafts for rotation relative to said housing (20) into and out of edge engagement (at 120) with the first mentioned damper. A high temperature control damper according to claim 3, wherein said edge engagement (at 120) comprises a ship-lap joint.

Inventors: ROGNE ALLAN W, ROGNE, ALLAN W.
Applicants: GRACE W R & CO, W.R. GRACE & CO.-CONN.
Application year: 1992
Main classification: F26B21
IPC codes: F26B21, F26B23