US2055071A - Sealing means for heat exchangers - Google Patents

Description

Sept. 22, 1936. E.:O. ERl-KSSON SEALING MEANS FOR HEAT EXCHANGERS Filed Nov. 5, 1931 2 Sheets-Sheet l fig. l

y INVENTOR M Q m BY a5- M ATTORNEY p 1936- E. o. ERIKSSON 2,055,071

SEALING MEANS FOR HEAT EXCHANGERS Filed Nov. '5, 1931 2 Sheets-Sheet 2 fig. 4- Tig. 6

M 42 1 v Pl Patented Sept. 22, 1936 PATENT [OFFICE SEALING MEANS FOR HEAT EXCHANGERS Erik Otto Eriksson, Lidingo, Sweden, assignor to 1Clqhe Air-Preheater Corporation, Wellsville,

Application November 5, 1931, Serial No. 573,119

In Sweden Novemberg, 1930 I 13 Claims.

My present invention relates to regenerative heat exchange apparatus, and has particular reference to improved sealing means therefor.

Regenerative heat exchange apparatus has 5, been utilized in which a relative rotation occurs between a cylindrical frame containing a regenerative mass, and inlet and outlet arrangements for the fluids between which the exchange of heat is to occur. Other forms of heat exchange constructions include a frame containing regenerative material and either mounted as a body of revolution for rotation in the fluid to be cooled and the fluid to be heated, or else mounted to bestationary and to be adjacent in fluid channels which move relatively to the frame,

so that similar heat exchange conditions are obtained.

Sealing means between the moving and the stationary parts have been utilized to reduce the go fluid leakagefrom one fluid passage to another. Such sealing means, for example, have utilized projecting parts adapted to frictionally contact the parts that have relative motion, their sealing being comparatively satisfactory for the channels in small heat exchanging apparatus. This type of sealing is not, however, sufliciently effective for larger sizes, because the frame containing the regenerative material is subjected to temperature variations tending to produce varying distances between the relatively moving parts, with the result that the sealing means satisfactory at one temperature is not satisfac tory at other temperatures.

The present invention pertains to a novel sealing construction that functions independently of temperature variations in the heat exchanger, and includes an annular element which'may have sealing means, and which cooperates with the cylindrical frame, the annular element having a relative rotary movement with respect to the frame and being mounted to follow such movements or changes in form of the frame as are produced by expansion due to heat.

Other advantageous features of the invention will be readily apparent from the detailed description following, in conjunction with the accompanying drawings.

In the drawings,

Fig. 1 is a diagrammatic elevation of a rotary type regenerative heat exchange apparatus embodying the novel sealing means;

Fig. 2 is an enlarged sectional detail of half an axial section of Fig. 1;'

Fig. 3 is a section on the line 3-3 of Fig. 2;

Fig. 4 is an enlarged fragmentary sectional detail showing a modified form of sealing means;

Fig. 5 is a fragmentary plan view of a heat exchanger embodying the modified form shown in Fig. 4, on a reduced scale;

Fig. 6 shows a further modified form; and

Fig. 7 is a fragmentary sectional view on the line '|-,I ofFig. 3.

In the heat exchanger diagrammatically shown in Fig. 1, a relative rotary movement occurs between the inlets and outlets for the two fluids between which heat exchange occurs and the regenerative mass I, the latter being mounted in a cylindrical frame a rotatable about the axis 2. The fluid to be cooled, which may for example be flue gases from a furnace, enters through the inlet 8 and exits through the outlet 9 after having transferred heat to the regenerative mass. The fluid to be heated, such as combustion air, enters through the inlet 8a and exits through the outlet-9a after absorption of the transferred heat in the regenerative mass.

I Fig. 2 discloses the left portion of the apparatus of Fig. 1 insection, and illustrates how the frame a is enclosed by a cylindrical jacket 3 within which the regenerative material is mounted, the latter preferably consisting of plane and corrugatedmetal plates. The jacket is connected to a central hub portion 5 of the frame by radially positioned partitions 4; the partitions 4 thus divide the frame into a number of segments which may be further subdivided by cylindrical plates 6 and I, particularly when the frame is of large diameter.

The specific heat exchanging apparatus described is an air preheater utilizing flue gases as the heat yielding medium, the flue gases passing through the air preheater in the direction indicated by the arrow l0. Preferably, fans are mounted in the conduit connecting the outlet 9 with the stack, for expelling the flue gases; the air is also preferably expelled by means of a fan or the like, thus compensating for the air preheater resistance and simultaneously providing forced draft for the furnace.

The rotor is enclosed by a casing II which may, if desired, be formed of plates which are joined together by welding and are of sufiicient thickness to obtain the necessary strength and tioned between the rotating frame and the stajacket 3' elevated; this eifect results from the differential expansion and the tensions of the rotor parts due to the diflerences'in temperature at the hot and cold ends. Although this elevation is counteracted by the weight of the rotor. it has been found that the elevation in an air preheater rotor having a diameter of five meters will amount to from to millimeters. The tendency towards becoming saucer shaped is greater if the gases are introduced to make the rotor hottest at its upper portion, or if the preheater is formed with a horizontal axis of revolution, as the alteration of shape'is not then compensated for by the weight of the rotor. The

sealing means and engaging edges that have been found most suitable for air preheaters of the type described must be adjusted to ilt between the rotor and the walls of the casing when the preheater is cold; when the air preheater is subjected to the heating effect of the gases and the rotor becomes saucer shaped, for example by 12 millimeters, the contacting edges will either be ground oil or become permanently offset away from the rotor edge for the distance the rotor edge is distorted. A play of 12 millimeters would therefore be produced between the rotating and the stationary parts between the preheater channels, the play being smaller if the temperature difierence is smaller, but being suflicient to cause a large detrimental leakage.

In order to ensure an approximately uniform distance between the rotating and the stationary parts, a ring or a ring segment I5 is utilized,

h vin a mounting which is changed in correspondence with changes in the shape of the frame produced by expansion due to heat. In this embodiment, the ring I5 is positioned about the rotor in proximity to the upper edge of the jacket 3 and a sealing edge It is mounted on the jacket 3 and extends towards the ring when the jacket is elevated; the ring l5 also moves so as to maintain the same distance from the jacket and therefore from the sealing edge l6, this movement being produced through the medium of an arm connected to the ring l5 and having a wheelor roller l8 on. the free end resting on a projecting part I! of the rotor jacket, which is preferably formed with an integral toothed rack cooperating with a pinion (not shown) for rotating the rotor. The roller I8 is journalled on the arm l! by means of one or more bearings, such as ball bearings, and rests on a plane portion of the part l9 that is perpendicular to the axis of rotation 2 of the rotor.

The ring I5 is rigidly connected to an arm or spoke "2| which in turn is pivotally connected with the casing II at a point adjacent the axis of rotation 2. In the construction illustrated the arm 2| is connected. to the casing II by a hinged joint, such as a bolt mounted in eyes. In previous constructions of air preheaters of the type described, disks formed of sheet metal and of the 7 2,055,071 vtionary casing H, in order to prevent peripheral from one channel to the othefthrough' a rotor segment. A I

In the present embodiment, the arm or spoke 2| may be formed as a segmentshaped plate of the same type, the radially disposed partitions l being provided with the usual sealing edges adjacent the segment plate and bearing on or being directed against the segment plate 2|. As the ring I 5 is" always mounted at approximately the same distance from the jacket 3, the segment plate 2| will also be positioned at approximately the same distance from the radially disposed plates 4, thus ensuring the same sealing effect for the contacting edge and preventing leakage from one channel to the other. 1

In certain constructions, the radial sealing de-, vice l8 may be arranged so that a complete movable ring I5 is not required. In such constructions, it is sufiicient to use the segment .plate 2| as the sealing means and'to keep it at a uniform distance from the radially disposed partitions 4 in the above described manner, the plate 2| thus acting as the ring portion which follows the \movement or altered shape of the frame produced by temperature variations.

Since changes in the sealing eflectare' not only produced in the hottest portion of the rotor, but.

also at the other end of the rotor, it is preferable to mount a ring 22 at the other end, which ring is connected through an arm Fla with the roller l8. The ring 22 is also movably connected to the rotor casing H as at 24 by means of spokes or the like or by an element 23 formed as a disk. Thus the sealing between the rotor and the parts l5, 2| and 22 and 23, which are relatively movable to a limited extent, is maintained constant or sub-' stantially constant.

This construction necessitates further sealing between the last named parts 22 and 23, which arrow 26, between the sealing edge 25 and the ring IS. The sealing edge may therefore be mounted so as to enter the U shaped portion of the ring and have its end surrounded with sand or some other heat resistant mass, this construction thus providing complete sealing while permitting relative vertical movement between the ring and the casing without appreciable wear. ,The wall 21 which separates the flow channels in the casing is also formed as a sealing edge and is adapted to enter a sand seal 28 (see Fig. 3). in a groove formed by angle irons 29 in the disk 2|.

Fig. 3 illustrates the preferred construction for the last described sealing device, and shows the sealing edge 21 extending radially through an opening, not shown, in the U shaped ring l5 as far as the sealing edge 25. 'A sealing edge 30 is arranged in the same manner, in the lower part of the rotor, see Fig. 2, within the ring 22, the edge entering into a sand seal 3| provided in a groove 32. Similarly, a sealing edge 33 is positioned on the disk 23,' and extends into a sand pocket 34 provided in a groove 35 in the casing H, see Fig. 3; in this case, also, the sealing edge 33'extends radially outward to the sealing edge 30.

The above described constructions admittedly provide double seals, but are preferred because there is no rotary movement between the seals that must correspond to the altered plane resulting from the rotor becoming saucer shaped,

namely, the seals between the movable plates 2 I, 23, and the frame II. On the other hand, the seals which prevent leakage between the rotating and non-rotating parts namely, the seals between i the rotor and plates 2|, 23, extend over a play or an intermediate space that is substantially constant. Consequently, the first type of seals may be formed with no consideration for wear becan be obtained than has been possible hereto-' fore.

Fig. 4" illustrates a modified arrangement, the upper part of the rotor and such parts as are. positioned adjacent the upper edge of the rotor \jacket 3 being shown. In this modification, the

rotor contains regenerative material having radially disposed partitions 4. The radial partitions are provided with sealing edges 4| directed against the segment-shaped disk 2| which either has an integral'annular portion or else is carried by the ring i 5, as preferred. Either the ring [5 or the plate 2i may extend beyond the upper edge of the jacket 3, or the ring l5may be positioned in the vicinity of the upper edge of the jacket 3.

The ring is attached to a shaft 42, on which a roller i8 is mounted by means of a ball bearing 43. The roller I8 contacts with and runs on the upper edge of the jacket 3. Consequently, the ring i5 and the segment-shaped plate 2! will al ways have the same position relatively to the upper edge of the jacket and the sealing edges of the plate 4i, whereby a very small play of uniform magnitude can always be maintained between said parts. A sealing edge 44 is positioned between the jacket 3 and the ring [5, and prevents the gas from flowing to the space radially outside the jacket.

The ring I5 is thus stationary relative to the rotor, but follows the rotor movements produced by variations in temperature, and is therefore movable with respect to the casing II in the manner described with reference to Fig. 1. For this reason, sealing means must also be provided between the casing II and the ring i5, said sealing means preferably consisting'of annular elements 46 pressed by springs 41 partly against the ring i5 and partly against the casing, these elements 46 thus preventing leakage from the upper part of the casing to parts thereof which are positioned radially outside the jacket.

The partition 48 which divides the casing into two channels is sealed against the segment disk 2| in the manner more fully disclosed in Fig. 5, in which reference numerals from Fig. 4 are used to designate correspondingparts. The sealing means consist of strips 52 suspended in hingelike attachments 50 and 5|, said strips bearing on the disk 2|. The strips 52 may be suspended directly in the upper part of the casing i I, if the available space does not allow room for a special partition 48; in certain cases, the hinged member 7 52 per se may constitute the partition in the casing on that side of the rotor. Upon movement of the disk 2i, which is of segment shape as indicated in Fig. 5, the movably suspended member 52 will assume different angular positions relatively to said casing. Fig. 5 also .discloses that the ring i5 is mounted on a plurality of rollers l8a, i8b, etc., the rollers being distributed along the periphery of the entire ring- When the rotor becomes dished, the ring l5 will not remain in one plane but will by reason of its resiliency take a form corresponding to the upper edge of the jacket 3.

On the other side of the rotor, corresponding ar- 5 rangements are resorted to for the necessary sealing.

In Fig. 6 the roller i8 is shown engaged with the upper edge of the jacket -3, and the ring I5 is suspended on the same shaft on which the roller 10 i8 is mounted by means of a ball bearing which does not permitspherical rolling. The sealing 'means' between the walls 4 of the roller and the partition 48 are similar to those described with reference to Figs. 4 and 5, this alsobeing the casewith the sealing edges 44 for preventing leakage between the ring l5 and the jacket 3. In contradistinction to the embodiment shown in Fig. 4, however, the sealing means between the ring i5 and the casing I i is shown ascomprising a flexible or resilient part 55, which is rigidly connected with the casing II and with the ring I 5. This part 55 may be made from flexible or slitted sheet metal, or may consist of other heat resistive insulating material, such as for example asbestos fabric.

In all constructions, the bearings of the roller l8 are'shown as accessible fromthe outside to facilitate lubrication. In Fig. 2, that portion of the arm which contains the bearing of the roller may also be mounted to partly extend outside the casing, in which case effective cooling of the bearings can be obtained.

With constructions according to the principle of j the invention, sealing means may thus be provided between rotating and non-rotating parts, so that approximately the same or a comparatively small play can always be secured between the various sealing parts. The seals between parts that will be positioned at different distances from each other may be provided between such parts as'do not rotate in relation to each other and which, therefore, are better adapted for the least possible leakage.

In accordance with the principles of the inven- Heat exchanging apparatus Obviously, the invention is not limited to the embodiments shown, as changes in the constructive details may be made to suit the requirements for. particular installations, within the spirit and scope of the invention as defined in the appended claims.

I claim:

1. Inaregenerative heat exchanger, acylindrical frame containing regenerative material, inlets and outlets for fluids to be cooled and to be heated, said frame and said inlets and outlets being relatively rotatable, and sealing devices between said relatively rotating parts having a relative movement with respect to the frame and including means compensating for distortion of the movable part produced by temperature varia- 7O tions, said means including a member in rolling contact with a frame surface in a plane at right angles to the cylinder axis.

- 2. In a regenerative heat exchanger, a channel for fluid to be cooled and a fluid to be heated, a

rotor having a plurality of segments and movable in said channels, a casing around said rotor, and

- sealing means between said channels including a member mounted adjacent the rotor and movably connected with said for movement axially with respect to said rotor. A

3. In a regenerative heat exchanger, channels for fluid tobe cooled and a fluid to be heated, a rotor having a plurality of segments and movable in said channels, a casing aroimd said rotor, and

sealing means between said channels including a member mounted adjacent the rotor and movably connected with said casing and secured to said casing adjacent the axis of rotation of said rotor.

4. In a regenerative heat exchanger, channels for fluid to be cooled .and a fluid to be heated, a

. rotor having a pluralityjof segments and movable in said channels, a casing around said rotor, and sealing means between said channels'including a member mounted adjacent the rotor and movably connected with said casing and pivotally secured to said casing adjacent the axis of rotation of said rotor.

5. In a regenerative heat exchanger, channels for fluid to be 0001811 and 8. fluid to be'heated, a

. rotor having a plurality of segments and movable in said channels, a casing aroimd said rotor,

sealing means between-said channels including an arcuate member mounted adjacent the rotor and movably connected with said casing, and segment shaped disk means pivotaiiy securing said arcuate member to said casing adjacent the axis x of rotation of said rotor.

6. In a regenerative heat exchanger, a casing having channels'for fluid to be cooled and a fluid to be heated, a rotor-having a plurality of segments and movable in'said channels, said rotor having a frame, and sealing means between said channels including an arcuate member mounted adjacent the rotor and having cooperating sealing elements respectively in sealing e gagement gagement with said casing,'and having rolling engagement with the upper edge of said frame.

8. In a heat exchanger, a rotor containing regenerative material and rotatable about a vertical axis, an annular member on said rotor, and sealing means including a. second annular member having rollers mounted thereon, shid rollers e a ng the upper surface of said first annular member.

9. In combination, a casing, a rotatable frame therein subject to distortion, a movable nonrotatable sealing element in sealing relation to I said casing, and means for maintaining said sealing element at a predetermined distance from said rotatable frame.

10. Incombination, a casing, a rotatable frame therein subject to distortion, a. movable nonrotatable sealing element in sealing relation to said and means secured to said sealing element and engaging said rotatable frame for maintaining said sealing element at a predetermined distance from said rotatable frame.

11. In combination, a casing, a rotatable frame therein subject to distortion, cooperating sealing elements comprising one element secured to the casing and a second element movable with respect to said first element, and sealing means between said rotatable frame and said second element.

12. In combination, a casing, a rotatable frame therein subject to distortion, cooperating sealing elements comprising one element secured to the casing and a second element movable with respect to said first element, sealing means between said rotatable frame and said second element, and means for shifting said second element in the direction of the axis of the rotatable frame.

13. In combination, a casing, a rotatable frame therein subject to distortion, cooperating sealing elements comprising one element secured to the casing and a second element movable with respect to said first element, sealing means between said rotatable frame and said second element, and means forshifting said second element in the direction of the axis of the rotatable frame to maintain a predetermined distance with respect to said frame, said means comprising mechanism secured to'said second sealing element and engaging said rotatable frame.

ERIK O'I'I'O ERIKSSON.

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