Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D19/00—Regenerative heat-exchange apparatus in which the intermediate heat-transfer medium or body is moved successively into contact with each heat-exchange medium
  • F28D19/04—Regenerative heat-exchange apparatus in which the intermediate heat-transfer medium or body is moved successively into contact with each heat-exchange medium using rigid bodies, e.g. mounted on a movable carrier
  • F28D19/047—Sealing means

Definitions

• the present invention in a first aspect relates to a rotary regenerative heat exchanger of the kind specified in the preamble of claim 1 and in a second aspect to a method for operating a rotary regenerative heat exchanger as specified in the preamble of claim 6.
• SE 176 375 discloses a rotary regenerative heat exchanger with a support in the form of rolling bodies, mounted in the outer ends of sector-shaped plates closed to both ends of the rotating part and rolling on a flange along the periphery at the top and bottom end of the rotor.
• graphite has excellent lubrication properties and like carbon has an ability to maintain the flanges of the rotating body clean when adhering a lubricating layer o carbon or graphite on the flanges.
• the abrasion of the sliding shoe also secures a correct contact with parallel contact surfaces so that the contact takes place on the complete sliding shoe surface.
• Carbon and graphite also have a good acceptance of the high temperature and the acid environment that are present. By the abrasion of the sliding shoes they will gradually be consumed and have to be replaced. The degree of abrasion, however, will vary widely, so that one or more sliding shoes might be worn down so much that the clearance reaches zero, whereas other sliding shoes will be almost unaffected.
• Each sliding shoe therefore is adjustable in a direction perpendicular to the contact surface.
• a similar solution is disclosed in WO95/00809, in which there is provided a measuring rod adjacent to the sliding shoe, which measuring rod is directed parallel to the adjustment direction. The measuring rod from a resting position can be momentary brought in contact with the related flange and indicates when the size of the clearance requires advancement of the sliding shoe a distance so that the initial clearance is restored.
• the object of the present invention therefore is to attain a regenerative heat exchanger of the kind in question in which the number of sliding shoes is as small as possible.
• the device according to the invention thus deviates from the traditional concept of using two or more supports for the sector plate, when supports of the non-contacting type are used.
• the problem of avoiding tilting is overcome by the stabilizing projections. Since these projections are arranged to normally be out of contact with the end surface on the flange of the rotor, wear problems will not occur. Should, however, there be a tendency for the plate to tilt, a projection will contact the flange and prevent tilting. The contact force in that case will be relatively small, since the stabilizing projections do not have to take part in keeping the plate raised from the flange, but only to counter-act the tilting force.
• the projections thus function as a kind of stabilizers that occasionally contact the flange, but mostly leave a small clearance in relation thereto.
• the air cushion support is located in the middle of the periphery of the sector plate with the stabilizing projections at both ends of the periphery.
• the stabilizing projections should preferably be somewhat shorter than the distance between the plate and the flange and it can be advantageous to make them resilient.
• fig. 1 is a partial section through a first preferred embodiment of a heat exchanger according t the invention
• fig. 2 is an axial section through the support means along line II-II of fig. 1
• fig. 3 is a schematic top view of a sector plate according to the first embodiment of the invention
• fig. 4 is a schematic section along line IV-IV of fig. 3
• fig. 5 is a view similar to that of fig. 3 and illustrating a second embodiment of the invention.
• the heat exchanger illustrated in fig. 1 is of conventional type having a stationary casing 1 an a cylindrical rotor 2 containing the regenerative mass 3.
• the rotor has a hub 4 and an upper fixed sector shaped centre plate 5 with a movable sector plate 6 pivotally connected thereto and corresponding lower fixed centre plate 7 and movable sector plate 8.
• the two sets of plates 5, 6 and 7, 8 have the function to seal against the upper and lower ends of the rotor 2 a tight as possible and thereby separate the heat exchanging media flowing to and from the roto through axial openings connected to media ducts (not shown).
• each of the movable sector plates 6, 8 are provide a device, which device forms support means 10 for maintaining a certain clearance between th ends of the sector plates 6, 8 and an upper and lower annular edge flange 12 attached to the rotor along its upper and lower peripheries, each flange having an outer circumferentially continuous end surface 61 for co-operation with a front surface 62 connected to each of the devices 10.
• Fig. 2 illustrates a part of the casing and the upper edge flange 12 of the rotor and the upper movable sector plate 6.
• the device 10 is fixed by screws.
• the device includes an outer sleeve 15 with a mounting flange 16, which with an intermediate sealing ring 17 is attached to the sector plate 6 by means of screws 18.
• the outer sleeve 15 has an internal thread 19 and within the outer sleeve 15 there is an inner sleeve 20 having an upper part with an external thread, partly screwed into the thread 19.
• the inner sleeve is provided with a packing 22, which sealingly contacts the inside of the outer sleeve 15.
• the upper end of the inner sleeve 20 is provided with a nut 23 welded thereto and its lower end is provided with a bottom plate 24 welded thereto.
• a gas cushion device 25 in the form of a circular sliding shoe 25 of graphite or carbon is exchangeable attached by means of a recessed screw 26 screwed into the bottom plate 24.
• the sliding shoe 25 has a front surface 62 facing and being parallel to the circumferentially continuous end surface 61 of the flange 12.
• the upper end of the outer sleeve 15 is provided with an external annular flange 27 to which the upper end of a sealing bellow 28 of metal is screwed by means of a mounting ring 29, an annular packing 30 and screws 31.
• the lower end of the bellow 28 is provided with a mounting ring 32, which by means of screws 33 and an intermediate packing 34 is attached in a circular hole in the casing 1 so that a pre- determined axial force will be applied downwards on the plate 6 due to the spring effect of the bellow 28.
• a measuring device 13 is provided for measuring the clearance between the plate 6 and the flange 12. It includes a tube 40, attached with its lower end in a hole 41 in the sector plate 6 and with its upper end in a hole 42 in the flange 27, and thus extends within the bellow 28. Inside the tube there is a measuring rod 43, the upper end of which is fixed in the shown position to a sleeve 44 by means of a not ⁇ shown spring and an external flange on the rod, which sleeve 44 is screwed on to the tube 40. In that position a scaled part 45 of the upper end of the rod 43 projects out through the sleeve 44, and the bottom end of the rod 43 is aligned with the underside of the sector plate 6.
• a measuring clock 50 having a measure probe 51 contacting the top end of the scaled part 45 can be provided.
• Support of the movable sector plate 6 for maintaining a clearance between the plate 6 and the flange 12 is attained through contact-free co-operation between a guiding surface 61 being the outer end surface of the rotating flange 12 and a stationary guided surface 62, being the front surface of the sliding shoe 25.
• means are provided for establishing a cushion of gas between these surfaces 61, 62.
• These means includes a pressurized gas source 64, connected through a pipe 63 to the interior 65 of the sleeve 20 in which the sliding shoe 25 is mounted.
• channels 66 communicate the interior 65 of the sleeve 20 with outlets 67 in the end surface 62 of the sliding shoe 25.
• the pressure of the gas is sufficient to force the gas to continuously flow from the outlets 67 and escape between the end surface 62 and the front surface 61, which thereby are pressed away from each other. In that way a cushion of gas is formed between these surfaces 61, 62, having an axial thickness of a fraction of a mm. Since there will be no contact between the surfaces 61, 62 no wear of the sliding shoe will occur.
• the upper movable sector plate 6 connected to the fixed centre plate 5 through pivot connections 71 is seen from above.
• the sector plate 6 is provided with the sole sliding shoe 25 of the support means 10.
• the sliding shoe 25 is located in the region o the symmetry line 69 of the sector plate 6 and faces the end surface 61 of the flange 12 of the rotor 2.
• the sector plate 6 at its radially outer end is supported by only one single sliding shoe 25 the plate is less stable, than when using two or more such shoes, and it therefore is a risk that the outer corners of the sector plate 6 might tilt.
• the sector plate is provided with an axially directed stabilizing projection 68 near each end of its outer periphery. As can be seen in fig. 3 these projections 68 are located so that they face the flange 12.
• Fig. 4 illustrates the function of these projections 68.
• the sector plate 6 is raised solely by the centrally located sliding shoe 25 and the gas cushion established between the shoe 25 and the flange 12. A clearance having a width S thereby is maintained between the sector plate 6 and the flange 12.
• the supports 68 are slightly shorter than the distance S between the sector plate 6 and the flange 12 so that the projections 68 normally do not contact the flange 12.
• the contact force between a projection 68 and the flange 12 will be relatively low since the projection does not contribute to maintain the plate raised, but only to prevent the tilting movement. There is therefore no need to concern about wear of these projections or to use self-lubricating material. These projections therefore can be made very simple.
• the projections 68 preferably are resiliently mounted or made of resilient material in order to attain a smother resistance against tilting and avoid bouncing.
• the sliding shoe 25 can be located on one side of the symmetry line 69 as illustrated in fig. 5. In that case the risk for tilting will be unidirectional and only one supporting projection 68 located at the other side of the symmetry line 69 adjacent to the radial edge 70 of the sector plate 6 is required.

Landscapes

• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
• Treatment Of Fiber Materials (AREA)
• Braking Arrangements (AREA)

Applications Claiming Priority (3)

Publications (2)

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ID=20397153

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• 1995
  • 1995-02-10 SE SE9500477A patent/SE504008C2/sv not_active IP Right Cessation
• 1996
  • 1996-02-09 DK DK96903292T patent/DK0807238T3/da active
  • 1996-02-09 EP EP96903292A patent/EP0807238B1/de not_active Expired - Lifetime
  • 1996-02-09 DE DE69611520T patent/DE69611520T2/de not_active Expired - Fee Related
  • 1996-02-09 WO PCT/SE1996/000157 patent/WO1996024813A1/en active IP Right Grant
  • 1996-02-09 PL PL96321713A patent/PL180424B1/pl unknown

Non-Patent Citations (1)

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