GB2074301A

GB2074301A - Regenerative Heat Exchangers

Info

Publication number: GB2074301A
Application number: GB8012709A
Authority: GB
Original assignee: Svenska Rotor Maskiner AB
Current assignee: Svenska Rotor Maskiner AB
Priority date: 1980-04-17
Filing date: 1980-04-17
Publication date: 1981-10-28
Also published as: GB2074301B

Abstract

In a regenerative heat exchanger having a heat transfer unit 1a rotatable relative to an enclosing casing 1b providing ducts conveying the fluids to and from the unit 1a, said unit comprises compartments 5 (for the heat transfer material) defined by partitions 4 extending radially between a cylindrical inner shell component 2 and a cylindrical outer shell component 3, at least some of the partitions being in sliding engagement with the outer shell 3 and all the partitions being fixed at one end thereof to one said shell component and slidable at their other end with respect to the other shell component; the partitions being in sliding engagement with a sealing ring 7 positioned between the unit 1a and the casing 1b. In Fig. 2 all the positions 4 are welded at one end to shell component 2 and are slidable at their other end in slots 6 of shell 3. Or, Fig. 7, alternate partitions may be slidable at one end in one shell component and welded at their other ends to the other shell component. <IMAGE>

Description

SPECIFICATION Rotary Regenerative Heat Exchanger Having Floating Sealing Rings This invention relates to rotary regenerative heat exchangers of the type comprising two main parts relatively rotatable with respect to each other about a common central axis: the first of said main parts constituting a regenerator body comprising an inner cylindrical shell interconnected with said inner shell by a plurality of radial partition walls forming a plurality of open-ended sectorial compartments containing a regenerator heat transferring material providing passages for flow of fluid media therethrough from and to the ends of the regenerative material, and the second of said main parts constituting a duct part providing ducts having inlets and outlets for flow of heat emitting and heat absorbing fluid media to and from the opposite ends of said regenerative material, at least one of the ends of said outer shell being provided with a sealing ring positioned in the clearance between said main parts.

In rotary regenerative heat exchangers of the type referred to a cylindrical rotor carrying the compartments of the heat transferring material is first exposed to a flow of heating fluid such as hot exhaust gas, that is directed through a limited portion of the rotor. Upon rotating the rotor about its axis, the heated heat transferring material is positioned in the path of a relatively cool fluid to be heated, such as air, whereby the heat of the heating fluid may be transferred thereto. The rotor is surrounded by a housing including a stationary duct part that simultaneously directs the heating and the cool fluids through the spaced compartments of the rotor.

The rotor is subjected to a substantial temperature gradient whereby the structural components thereof warp and distort to the extent that effective sealing between the rotor and enclosing housing is difficult if not impossible to obtain.

It is therefore a primary object of this invention to provide a rotary regenerative heat exchanger whose sealing surfaces are not subject to the usual excesses of thermal distortion.

Due to a non-uniform temperature distribution, and especially under certain conditions, such as overload, the thermal deformation of the structural components, as the radial partition walls, often results in fracture of any weld joints and other damage involving deformation of the sealing surfaces.

Therefore it is also an object of this invention to provide a rotor or regenerator body in which the weld joints are relieved from dangerous stresses.

A known regenerative heat exchanger having a cylindrical rotor carrying heat transfer material and having rigid sealing rings is disclosed in U.S.

Patent specification 2,981,521 and a similar heat exchanger is disclosed in British patent specification 1,376,122. In both cases the sealing rings are fixedly attached to rigid radial or diametric partition walls or webs the thermal expansion of which in radial direction gives rise to deformation of the sealing rings.

Another rotary regenerative heat exchanger is disclosed in British Patent specification 1,046,106 in which the heat transferring material is supported by rigid radial diaphragms extending radially outward from the inner shell to the concentric outer shell forming a part of the sealing means and subjected to radial deformation forces.

The present invention provides a regenerator body structure that isolates the supporting structure from the sealing structure so that thermal deformation of the support structure does not give rise to any deformation of the rigid sealing ring.

According to the invention, a rotary regenerative heat exchanger comprises two main parts, rotatable with respect to each other about a common central axis, a first of said main parts constituting a regenerator body comprising an inner cylindrical shell and an outer cylindrical shell interconnected with said inner shell by a plurality of radial partition walls forming a plurality of open-ended sectorial compartments containing a regenerative heat transferring mass providing passages for flow of fluid media therethrough from and to the ends of the regenerative mass, and the second of said main parts constituting a duct part providing ducts having inlets and outlets for flow of heat emitting and heat absorbing fluid media to and from the opposite ends of said regenerative mass, at least one of the ends of said outer shell being provided with a sealing ring positioned in the clearance between said main parts and the outer or the inner end of each radial partition wall is slidingly adopted in an axial slot in the outer or inner shell, respectively, the remaining end of each partition wall being fixedly attached to the corresponding outer or inner shell respectively, at least some of the partition walls being slidingly in engagement with the outer shell, in addition to which said partition walls also slidingly engage said sealing ring.

Although it is obvious that the invention is applicable to heat exchangers having a rotating component carrying the regenerative mass and a stationary component comprising fluid ducts, as well as to heat exchangers having a stationary component carrying the regenerative mass and a rotating component comprising fluid ducts, the following specification describes by way of example the first-mentioned kind of heat exchangers for the sake of simplicity.Specific embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a sectional elevation view in diagrammatic form of a rotary regenerative heat exchanger constructed according to this invention; Figure 2 is a plan view of the device as seen from section lI-Il in Fig. 1; Figure 3 is a fragmentary sectional view showing a portion of a sector plate and a sealing ring; Figure 4 is a similar view showing a special sealing ring centering device; Figure 5 is a section on line V-V in Figure 4; Figure 6 is an enlarged fragmentary sectional view of a slip joint between a partition wall and the outer cylindrical shell; and Figure 7 is a fragmentary sectional plan view showing a further embodiment of the slip joint between partition walls and the outer and inner shells.

The rotary regenerative heat exchanger shown in Figs. 1 and 2 comprises a rotor 1 a having an inner cylindrical post shell 2 and an outer cylindrical shell 3 interconnected with said inner shell by a plurality of radial partition walls 4 forming a plurality of open-ended sectorial compartments containing baskets of heat transferring metal plates (not shown).

The partition walls 4 have inner ends welded to the rotor post and outer ends slidingly journalled in axial slots 6 in the outer shell 3 and in radial slots 7 of two rigid sealing rings 8, 9 sealingly connected to the spaced ends of the wall segments of the outer shell 3. The upper sealing ring 8 is welded to said wall segments and the lower sealing ring 9 is suspended by means of links 10 secured to the upper sealing ring 8. The lower sealing ring 9 is provided with a circular groove 11 receiving the bottom ends of the wall segments 3.

Thus, the outer ends of the radial partition walls 4 are displaceable radially in the axial slots 6 of the outer shell 3 and the radial slots 7 of the sealing rings 8, 9. The sealing rings are positioned concentric to the inner shell 2 and outer shell 3 by the partition walls 4 which together with the slots 7 do not permit displacement of the sealing rings 8, 9 perpendicular to the radial partition walls 4 and the lower sealing ring 9 is suspended by means of links 10 secured to the upper sealing ring 8. The lower sealing ring 9 is provided with a circular groove 11 receiving the bottom ends of the wall segments 3.

Thus, the outer ends of the radial partition walls 4 are displaceable radially in the axial slots 6 of the outer shell 3 and the radial slots 7 of the sealing rings 8, 9. The sealing rings are positioned concentric to the inner shell 2 and outer shell 3 by the partition walls 4 which together with the slots 7 do not permit displacement of the sealing rings 8, 9 perpendicular to the radial partition walls 4.

The heat exchanger is provided with the usual sector plates 12 st opposite ends of the rotor 1 and the radial partition walls are provided with flexible radial sealing members 13.

Under certain conditions a "turn-down" of the radial partition walls 4 takes place due to thermal deformation of the rotor structure. The sector plates 12 and radial sealing members 13 are also turned down by an angle as shown in Fig. 3, but the rigid sealing rings 8, 9 and the outer shell segments 3 are not deformed but are only displaced a corresponding distance downwards.

In Figs. 4 and 5 at least the sealing ring 8 is connected to the rotor post by a centering device comprising a series of radially extending flexible wire-spokes 14. The spokes 14 may be used during the construction of the heat exchanger and may be removed after that.

Figs. 6 and 7 show another embodiment of the invention in which an integral outer shell 3 with interior axial channel members 17 are used in substitute for the outer shell segments 3 and slots 6. Every second partition wall 4 is welded to the inner post shell 2, each having its outer end portion slidingly received in one of the channel members 1 7 which is welded to the outer shell 3.

The remaining partition walls 4 are welded to the outer shell 3 each having its inner end portion slidingly received in a corresponding axial slot 18 in the rotor post shell 2. In this case the upper sealing ring 8 is floatingly supported by the outer shell 3 guided only by exterior radial wall portions 4' welded on the outer shell 3 and forming extensions of the partition walls 4. It is a;so possible to arrange the partition walls 4 such that all partition walls 4 are fixedly attached, for instance welded, to the rotor post 2, and all outer ends of the partition walls 4 are slidingly received in channel members 17.

Claims

1. A rotary regenerative heat exchanger comprising two main parts relatively rotatable with respect to each other about a common central axis, a first of said main parts constituting a regenerator body comprising an inner cylindrical shell and an outer cylindrical sheel interconnected with said inner shell by a plurality of radial partition walls forming a plurality of open-ended sectorial compartments containing a regenerative heat transferring mass providing passages for flow of fluid media therethrough from and to the ends of the regenerative mass, and the second of said main parts constituting a duct part providing ducts having inlets and outlets for flow of heat emitting and heat absorbing fluid media to and from the opposite ends of said regenerative means, at least one of the ends of said outer shell being provided with a sealing ring positioned in the clearance between said main parts and the outer or the inner end of each radial partition wall is slidingly adopted in an axial slot in the outer or inner shell, respectively, the remaining end of each partition wall being fixedly attached to the corresponding outer or inner shell respectively at least some of the partition walls being slidingly in engagement with the outer shell, in addition to which said partition walls also slidingly engage said sealing ring.

2. A heat exchanger according to Claim 1 wherein the sealing ring is provided with radial slots or similar guiding means for the radial edges of the partition walls.

3. A heat exchanger substantially as hereinbefore described with reference to, and as illustrated in, the eccompanying drawings.