US3384156A

US3384156A - Rotary regenerator

Info

Publication number: US3384156A
Application number: US644860A
Authority: US
Inventors: Albert N Addie
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1967-06-09
Filing date: 1967-06-09
Publication date: 1968-05-21
Anticipated expiration: 1985-05-21
Also published as: GB1183167A; FR1571578A

Description

y 1968 A. N. ADDIE 3,384,156

ROTARY REG ENERATOR Filed June 9, 1967 4 Sheets$heet 1 ATTORNEY May 21, 1968 A. N. ADDlE ROTARY REGENERATOR 4 Sheets-Sheet 5 Filed June 9, 1967 y 1968 A. N. ADDIE ROTARY REGENERATOR 4 Sheets-Sheet 4 Filed June 9. 1967 INVEN'TOR. fl/bm 77. M18

Yaw M ATTORNEY United States Patent 3,384,156 ROTARY REGENERATOR Albert N. Addie, La Grange Park, IlL, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed June 9, 1967, Ser. No. 644,860 11 Claims. (Cl. 165-8) ABSTRACT OF THE DISCLOSURE A rotary regenerator of the drum matrix type particularly adapted for use with gas turbines and also suited for a locomotive installation. The regenerator matrix is located and supported by two parallel rollers engaging the matrix rims at the inner or hot face of the matrix adjacent the bulkhead. The main seals are pivoted adjacent the drive rollers so that they can rotate to align with the matrix notwithstanding expansion and distortion. The angular position of the main seals is determined by aligning rollers engaging the outer or cold face of the matrix and mounted on the main seal frame. These are biased into engagement with the matrix by springs. These springs, and also the gas pressures on the matrix when the engine is operating, press the matrix against the hot side rollers, one of which drives the matrix by friction against the rims. A pressure-responsive device reduces the spring loading on the aligning rollers as the pressure rises on the engine. Bumpers o-r dampers prevent sudden loosening movement of the aligning rollers in response to shock loads. The support rollers and the main seal assemblies are supported on the case and bulkhead of the regenerator and the matrix is located radially and axially at these points and is additionally located axially by rollers engaging the rims of the matrix at a circumferential point remote from the main seals.

Introduction My invention relates to regenerators, by which I mean heat exchange devices of the sort in which a heat retaining mass is rotated so as to move alternately through the flow paths of two fluids so as to absorb heat from the hotter fluid and release it to the cooler. In some respects, it is particularly concerned with a regenerator having a drum matrix in which flow takes place radially through an annular drum, and with one suited to a gas turbine type of installation. The installation in a gas turbine involves substantial pressure differences between the two fluids, with attendant problems in supporting the matrix :and sealing against leakage from high to low pressure. It also involves high temperatures. One field for which my regenerator is particularly intended is in a locomotive and, therefore, it involves adaptations to the substantial shock loads that may occur in such service.

The advantages in terms of efliciency of providing a regenerator in a gas turbine engine are well known, and various regenerative engines have been built. The regenerator structure which is the subject of this application is intended for the large regenerative gas turbine engine described and claimed in the copending application Ser. No. 641,385 filed May 25, 1967, of the late John K. Dixon, Charles J. McDowall, Wilfred C. Oestrike, and myself for Gas Turbine Engine.

The principal objects of my invention are to improve the reliability and durability of regenerators; to provide a regenerator structure particularly adapted for gas turbine service; to provide a regenerator having improved mea s for supporting and driving the matrix particularly adapted to horizontal axis matrices of large size; to provide reli- "ice able friction drive means for a matrix; to provide a main seal between high and low pressure chambers in the matrix which maintains correct alignment with the matrix notwithstanding dimensional changes of the matrix and the cooperating stationary structures; to provide means for establishing a loading of the matrix against the supporting rollers which remains generally constant notwithstanding changes in pressure between various operating conditions of the engine; to provide a matrix support which is yieldable in response to gradual thermal changes but resists movement due to shocks encountered in service; and to provide improved lubricating, sealing, and cooling structure for regenerator driving and locating arrangements.

Various ones or all of these objects may be realized, depending upon the articular installation and the characteristics of a particular design according to my invention, but the regenerator as a whole is particularly suited to realize the various objects in the locomotive environment for which it is primarily intended.

The nature of my invention and the advantages thereof will be apparent to those skilled in the art from the succeeding detailed description of the preferred embodiment of the invention and the accompanying drawings thereof.

FIGURE 1 is a somewhat schematic side view, with parts cut away, of a regenerator and gas turbine arrangement.

FIGURE 2 is a sectional side view of the upper main support, main seal, and adjacent structures.

FIGURE 3 is a sectional view taken on a plane substantially coinciding with a plane containing the axis of the matrix, as indicated by the line 33 in FIGURE 5.

FIGURE 4 is .a detail sectional view taken on the plane indicated by the line 4-4 in FIGURE 5.

FIGURE 5 is an axial view of the primary seal assembly and adjacent mechanisms on the plane indicated by the line 5-5 in FIGURE 3, with parts cut away.

FIGURE 6 is a longitudinal sectional view of a seal biasing mechanism.

FIGURE 7 is a fragmentary sectional view taken on the plane indicated by the line 77 in FIGURE 5.

FIGURE '8 is a fragmentary sectional view taken on the plane indicated by the line 8-8 in FIGURE 7.

FIGURE 9 is a sectional view of the main seal taken in a plane perpendicular to the axis of the regenerator.

Referring first to FIGURE 1, which illustrates in a general way the nature and environment of the regenerator as part of the gas turbine engine described in the copending application referred to above, a gas turbine engine includes a turbine 13 which drives a compressor 14 through a shaft 15 and also drives a power output shaft 17. The compressor supplies air to a regenerator 18 which comprises a regenerator case or housing 19 and at least one drum-shaped regenerator matrix 21; preferably, two matrices rotating about the'sarne horizontal axis 22 perpendicular to the axis of the turbine. The matrices are disposed generally side by side wilh the turbine partially within the matrices and enclosed within the regenerator case. A bulkhead 23 and associated structure divides the interior of the regenerator case between a high pressure chamber 25 into which the compressor discharges and a low pressure chamber 26 into which the turbine discharges. Main support and seal assemblies 27 are mounted in the bulkhead at the places where each drum passes through the bulkhead as it is slowly rotated about the axis 22. Air compressed by the compressor flows radially inwardly through the forward roughly sector of the matrix, through combustion apparatus (not illustrated), and through turbine 13 to chamber 26 at the rear side of the bulkhead, where the turbine exhaust flows radially outward through the rear sector of the 3 matrix to an exhaust stack 29. As will be apparent, the structure as so far generally described is similar to that of prior U.S. Patents No. 3,116,605 to Amann et al. and No. 3,077,074 to Collman et al.

Regenerator In the following discussion of the regenerator, reference will be made to only a single one of the two duplicated regenerators, which are essentially mirror images of each other within a common housing, the housing also being partly divided. Also, the main support and seal assemblies 27 for each matrix are essentially mirror images of each other except that only the upper one provides the drive the rotate the matrix.

For the purpose of further description, We may consider the regenerator case 19 to comprise a radially outer wall 30 broken by the entrance from the compressor 14 and by the exhaust stack 29; a rear wall 31; and a front wall principally defined by a cover 33 which bolts onto the remainder of the case. The matrix 21 is supported by a drive roller 34 (see also FIGURE 3) mounted within the upper main seal and support assembly 27 and by an idler roller 35 mounted within the lower main seal and support assembly 27, the radially inner face of the matrix being in engagement with these rollers to locate, support and rotate the matrix.

The assemblies 27 also include biasing or aligning rollers 37 (FIGURE 3) which bear against the radially outer face of the matrix. The matrix is located along its axis of rotation by structure in the main seals at 27, to be described, and by locating rollers 38 (FIGURE 1) engaging the sides of the matrix, mounted on the front and rear walls of the case. Thus, the means to resist axial displacement of the matrix is disposed at three points approximately equidistant around the circumference. The structure described in this paragraph bears some resemblance to those disclosed in prior US. patents of Miller, No. 3,186,478 and Collman et al., No. 3,267,674.

Main support and matrix drive We may now proceed to consider in some detail the structure of the support, roller, and main seal arrangements as shown particularly in FIGURES 2, 3, 4, 5, 7 and 8. These illustrate the upper assembly 27 associated with the driving roller 34 for the matrix. The main sup port and seal assembly 27 includes a rigid main support frame 40 including front and rear side plates 41 and 42 (FIGURE 3) joined by three parallel struts or spacers (FIGURE 2). These are a case spacer 43, a bulkhead spacer 44, and a third spacer 45. Cap screws and dowels extend from the end plates 41 and 42 into the ends of these three spacers. The case spacer 43 bolts to a rib 47 on the case which extends inwardly from the outer wall 30. The bulkhead spacer 44 bolts to the bulkhead 23. The side plates 41 and 42 have circular bosses 49 projecting from their external faces, these bosses being received in openings in the rear wall 31 and cover 33, thus aligning the frame with the regenerator case. Also, the plates 41 and 42 bolt to

walls

31 and 33 so that the main support frame 40 constitutes a structure extending from the rear wall to the front wall and from the bulkhead effectively to the outer wall 30 of the case.

The drive roller 34 shown principally in FIGURE 3 comprises a shaft 54) and two generally conical wheels 51 pressed onto and keyed to the shaft. The outer ends of the shaft are supported in needle bearings 53 and 54 mounted in inwardly projecting bosses 55 on the plates 41 and 42. Seals 56 are disposed between these bearing and the Wheels. The inner race of bearing 54 and the adjacent seal 56 are retained by a nut 57. At the cover end of the shaft, a needle thrust bearing 58 is disposed between needle bearing 53 and a retaining nut 59. The thrust bearing reacts against a shoulder of a counterbore 62 in the case and against a cap or fitting 63 bolted to the plate 41. Seals 56 are contact type seals of the sort in which a steel ring rotating with the shaft bears against a carbon ring fixed in the boss 55, the purpose of these seals being to keep hot compressed air out of the shaft bearings and to retain lubricating oil.

The roller 34 is driven by a quill shaft 65 which extends the length of the shaft 50 and is spaced from the shaft to provide some tolerance for shifting of the parts. The left end of the shaft 65 as illustrated in FIGURE 3 is coupled to gearing (not illustrated) in the engine which rotates it. The other end of the shaft is splined at 66 to cooperate with mating internal splines on shaft 50. Some of the spline teeth are removed to allow space for passage of oil.

Oil to lubricate the bearings 53, 54, and 58 is supplied by a suitable pump (not illustrated) to an oil fitting 67 on the cap 63 from which it flows through orifices 69 into the interior of shaft 50. Piston ring seals are provided at 70 between the cap and shaft. Part of this oil flows outwardly through radial ports 71 at the front end of the shaft, through bearing 53 and key 58, and into a space 73 in the cap which communicates with a drain line. A further part of the oil flows through shaft 50 and radial ports 74 to lubricate the rear bearing 54, from which it flows into a flexible shaft housing 75 which connects the plate 42 to a fixed frame of the engine (not illustrated), which supports the regenerator case and within which the drive for shaft 65 is located. The nature of the engine frame and drive for shaft 65 are disclosed in application Serial No. 641,385, referred to above, and details are immaterial to the present invention. Oil can drain through the frame into the engine sump. A radially floating ring 77 which is a slip fit on quill shaft 65 bears against the inner surface of nut 57 to provide a seal or dam against undue escape of oily between the quill shaft and shaft 50 into housing 75. The margin of ring 77 has clearance from the nut.

The idler roller 35 mounted in the lower main seal assembly 27 is essentially the same as the drive roller 34 and will not be described. In the case of the idler roller, there is no quill shaft, and a fitting to conduct the scavenge oil to a line to the engine sump is fitted in a location corresponding to that of the shaft housing 75 of FIGURE 3.

The details of the matrix 21 are generally immaterial to the present invention. The matrix must be such as to provide a rim or other equivalent surface on the inner and outer faces of the matrix to bear against

rollers

34, 35, and 37. The preferred form of matrix is similar to that disclosed in abandoned US. patent application Ser. No. 484,219 for Regenerator Matrix, filed Sept. 1, 1965, of common ownership with this application. It is sufiicient presently to note that the matrix 21 comprises two rigid rims or end rings 78 held in spaced coaxial relation by stiffeners 79 (FIGURES 2 and 3) between which is mounted a body 80' of heat transfer and storage material previous to flow radially of the matrix. The wheels 51 bear against the inner diameter of the two rims. The biasing, pressure, or aligning rollers 37 shown in the upper part of FIGURE 3 bear against the outer diameter of the rims.

Main seal Rollers 37 are mounted in a main seal frame 8-1, which is a rigid structure cooperating in providing a seal between the bulkhead and the matrix 21, mounting the rollers 37, and providing an enclosure for the drive and idler roller structure previously described. It should be remembered, however, that the drive and

idler rollers

34 and 35 are supported on the main support frame 40 independently of the main seal frame 81 which can move slightly with respect to the frame 40.

The main seal frame 81 comprises a rigid cold side housing 82 which supports the aligning rollers 37 and two end plates 83 which have openings 85 through which bosses 55 of the side plates 41 and 42 project with clearance. iPiston ring seals 86 disposed in circumferential grooves in bosses 55 bear against the walls of the openings 85 and permit movement of the end plates relative to plates 41 and 42. Cap screws 84 fix plates 83 to housing 82. The main seal frame 8d. also includes a hot side housing '87 enclosing the roller 34. The hot side housing comprises two telescoping roughly cylindrical part-s referred to as the outer hot side housing 88 and the inner hot side housing 89. .The inner hot side housing 89 has a bellshaped end 90 which is secured by cap screws 9'1 to one end plate 83 and the outer hot side housing is similarly configured and attached by cap screws 9'1 to the other end plate. The

housings

87 and 89 are provided with two sets of cooperating splines 93 so that they can slide within each other but not rotate relatively. This structure allows for thermal expansion of the parts of the hot side housing, the spacing of the end plates 83 being determined by the cold side housing '82. The splines resist warping or wracking of the main seal frame 81. A piston ring seal 94 excludes the hot compressed air from entering between the hot side housings. The double-Walled structure of housing 87 reduces heat flow to roller 34 and its bearings. The radially inner ends 95 of the end plates are disposed with slight lateral clearance in slots in blocks 97 bolted to the front and rear plates 41 and 42 to assure that the end plates '83 move with the plates 41 and 42 in the event of any tendency of splines 93 to stick.

The main seal frame 8l1 is located by the engagement of the aligning rollers 37 with the rims 78 and by two trunnions 98 (FIGURES 4 and 5) extending rigidly from end plates 83. These trunnions are mounted in plates 4'1 and 42 by spherical bearings 96 as shown in FIGURE 4. The spherical bearings 96 are retained by bearing caps 99 bolted to the plates 41 and 42, and piston ring air seals 100 are fitted between the trunnions 98 and cap 99. The trunnions 98 also provide for circulation of oil into and out of the main seal frame, an oil inlet fitting 101 being disposed on the outer trunnion and an oil outlet fitting 102 on the inner trunnion. Note that the trunnions are located approximately at the mid-radius of the matrix 21 and are located adjacent the high pressure end of both seals displaced from the plane joining the axes of rollers 34 and B7.

Proeceding now to the aligning rollers '37, each such roller is rotatably mounted on a needle bearing 103 (FIG- URE 3) mounted on a boss '105 extending from the base of a recess in the end of the cold side housing 82. The roller is retained by a disk 106 bolted to the housing 8 2. Disk 106 includes a plug portion 107 bearing a circumferential seal which closes the end of a passage 109 extending from end to end of the cold side frame, which passage is enlarged at 110 intermediate the ends of the frame. The margin of disk 106 is disposed between an inwardly directed flange on roller 37 and a roller cap 111 bolted to the annular end of the roller, providing a thrust bearing. A contact type seal 113 is disposed between housing 82 and roller 37 in the inner end of the counterhore. This seal acts to keep the compressed air in the regenerator from flowing into bearing 103. The bearings 103 are packed with grease and have no oil circulation through them. However, oil is circulated through the cold side housing 82 to cool the housing and prevent unduly high temperatures in bearings 103. This oil circulates from the fitting 101 (FIGURE 3) into the trunnion 98 (FIG-URE 5), through drilled passages 114 in the end plate 83 and drilled passages indicated at 115 and 116 (FIGURE 3) in the cold side housing, into the passage 109. An inner oil tube 117 mounted in the passage 109 is provided with flanges mounting seals at 118. The ends of this tube are slightly spaced from the plugs 107. The oil thus introduced flows from passage 115 over the outer surface of tube 117, through the tube 117 to the interior of boss 105 at the other end of housing 82, then reverses over the outside of the tube and is discharged to the sump through a passage -1 19 indicated partially in FIGURE 3 and subsequent drilled passages in the main seal frame to the oil outlet fitting 102. Thus, a circulation of cooling oil is maintained, and the packed bearings 103 are sealed by the plug 107 from the oil and by the contact seal 113 from the compressed air.

Contact of the aligning rollers 37 with the matrix rim is maintained by biasing the upper main seal frame 81 counterclockwise as viewed in FIGURES 1 and 2, and the lower main seal frame clockwise, about the axes defined by their trunnions 98. The cold side housing 82 has two bosses 121 projecting from it, one near each rim of the matrix. Each of these is engaged by a piston rod *1-22 forming part of a biasing assembly 123 which will be described.

Primary seal Considering now the primary seal 125, which is the portion of the main seal directly cooperating with the matrix, this is an open-ended box or frame, mounted on frame 81, extending across the faces and ends of the matrix. The primary seal 125 involves a hot face seal bar 126 at the hot inner face of the matrix and a cold face seal bar 127 engaging the radially outer face of the matrix. These seal bars, as well as the cold side and the hot side frames, having openings cut in them so that the rims of wheels 51 and rollers 37 can engage the matrix approximately in the surface of the seal bars. These seal bars have a slightly curved surface to conform to the curvature of the matrix. The seal bars 126 and 127 are connected together at each end by roughly rectangular primary seal end plates 137. Seal bar 127 is in two parts meeting midway between plates 137. Bolts extend from end plates 137 into the ends of the seal bars to make a rigid rectangular frame.

The low pressure edge of end plates 137 have grooves 136 (FIGURE 5) cut in their outer surfaces to increase the flexibility and amenability to temperature changes of the end plates. Thus the plates 137 can fiex in response to differential thermal expansion of the seal bars 126 and 127.

Each primary seal end plate has a window 138 within which is mounted a floating end shoe 139 which bears against the end face of the matrix rim. Each end shoe 139 is retained by a cap 141 bolted to the main seal frame end plate 83, which cap provides a socket within which a boss 142 on the end shoe is received. A compression spring 143 lodged between the cap and shoe biases the shoe against the matrix rim. The shoe is self-aligning to conform to the rim.

The primary seal is mounted in the main seal frame 81 as follows (see FIGS. 2 and 9): The hot side outer housing 88 is provided with a fiat inner surface 148 with a step 149 near the high pressure side and a step 150 near the low pressure side. The hot side seal bar 126 has a rear or non-contact face which lies against this surface of the hot side housing and has shoulders which align it with the housing. Bolts 151 extend through the housing into a retainer strip 153 which overlies a flange on the high pressure edge of the seal. A retainer strip 154 which is bolted to the low pressure edge of the seal bar 126 engages a flange 155 on the outside housing. The seal bar can thus expand and contract axially of the matrix relative to the housing which supports it. A key 157 (FIG. 2) extends from retainer strip 154 into a keyway 158 in the bulkhead spacer 44. A pin 159 locates seal bar 126 on retainer 154 axially of the matrix. This arrangement allows some play radially and circumferentially of the matrix, but locates the seal bar 126 axially of the matrix at a point halfway between the rims of the matrix. The seal bar 126 can slide axially of the matrix relative to its support on the hot side housing 87.

The means for retention of the cold side seal bar 127 are similar to those for the hot side seal bar. A retainer strip 161 bolted to housing 82 retains the high pressure edge of the seal bar and a retainer 162 bolted to the seal bar 127 retains the low pressure edge. The seal bar rests against the inner surface of housing 82 and is located by axially extending shoulders. Seal bar 127 and retainer 162 are divided at the middle, as will be seen.

The two halves of cold side seal bar 127 are located axially of the matrix relative to the cold side housing 82 '2'" by dowels (not illustrated) extending from each half of the seal bar into the housing adjacent the central split line of the seal bar. It will be seen, therefore, that seal bars 126 and 127 are free to expand differentially from the housings on which they are mounted.

The main seal frame 31 is located in the regenerator housing in the direction axially of the matrix by a key 173 (FIGURES 2 and at the midspan of the cold side housing 32. This key is engaged in a vertical slot or keyway 174 out in the case spacer 43 which extends between the front and rear walls of the regenerator case. This key and keyway arrangement provides clearance for movement radially and circumferentially of the matrix between the parts to the extent necessary to allow for expansion of the parts and alignment of the primary seal with the matrix. The main seal frame and thus the primary seal cold side are located axially of the matrix and in turn axially locate the matrix.

Secondary seal Another area which needs to be protected against leakage is around the exterior of the primary seal 125 from high pressure to low pressure; for this purpose a secondary seal 183 is provided. The secondary seal in cludes a rectangular light sheet metal frame or diaphragm 186 which bridges the gap between the primary seat frame 125 consisting of

bars

126 and 127 and end plates 137 and the fixed structure of the engine comprising the front and

rear walls

33 and 31 and the

spacers

43 and 44. As shown most clearly in FIGURE 5, the low pressure ends of plates 137 are in the form of an are centered on the trunnion 98. The thin sheet metal diaphragm seal 18d lies over the end of the primary seal and extends outwardly from the primary seal frame. It is retained on the primary seal frame by two U-shaped retainer strips 188 and 189, which together define a rectangular frame lying on the low pressure side of the diaphragm 186 and are bolted to the low pressure edges of the primary seal bars and primary seal end plates. The outer edge of the rectangular sheet metal diaphragm is mounted against flanges 191 on

spacer

43 and 192 on spacer 44, and similar structure on the front and rear side plates 41 and 42. A two part frame comprising two

U-shaped sections

194 and 195 bolted to the fixed structure retain the diaphragm seal on the fixed structure. The retainers are in two parts so that they can be assembled around the matrix. The diaphragm 136 has edge clearance to provide for relative expansion or swinging movements of the parts and acts as a contact type secondary seal.

The seal diaphragm 186 is made from a .032 inch sheet of Inconel X with an Inconel X wire bead electron-beam Welded to both the inner and outer edges. The clearance gap between the diaphragm 136 and the retainers at the inner and outer edges is preferably five to ten thousandths of an inch to minimize leakage yet permit rotation of the primary seal about its trunnions without excessive friction at the secondary seal.

Radial flow past the matrix; that is, inward or outward flow going past the outside of the rim of the matrix instead of through the heat transfer material 80, is prevented in the main seal structure by arcuate by-pass seal shoes 196 mounted on plates 41 and 42 (FlGURES 3 and 5) which bear against an arcuate rib 127 on the outer surface of plate 83. These by-pass seals are biased against plate 33 by compression springs 198 and the seal strips bear against a radial shoulder on the front and rear side plates 41 and 42. The seals are retained by a retainer strip 199 secured to the inner face of the plate 41 or 42 by cap screws.

A filler strip 2tl2 is bolted to the bulkhead spacer 44 over the corners of diaphragm seal retaining frame portions 195. This part is recessed to clear the heads of the bolts which secure diaphragm retainer 189 to the primary seal frame 125.

By-pass and miscellaneous seals A by-pass seal shoe 204 (FIGURES 7 and 8) is mounted in a slot 205 in the hot side seal bar 126 adjacent each rim and adjacent the low pressure edge of the seal bar. The shoe 204 bears lightly against the radially inner surface of the rim of the matrix and is biased into contact with it by two leaf springs 206 mounted back to back in the space between shoe 294 and the bottom of slot 205. This shoe is provided to prevent bypassing of the matrix by flow going radially through the matrix.

A by-pass seal mounted on each of the side plates 41 and 42 at the high pressure side of the main seal cooperates With the inner diameter of the rim to prevent by-pass. The purpose of this is the same as the seal shoe 204, but the structure is somewhat different. A retainer 210 fixed on plate 41 or 42 and the spacing block 211 locate a bypass seal shoe 212. Leaf springs 213 bias the shoe against the matrix rim.

Between the two main seal assemblies, by-pass seals mounted on the front and rear walls of the regenerator case are provided. These (not shown) may be of the type disclosed in US. patent application Ser. No. 522,861 of Charles H. McCreai-y for By-Pass Seal, filed Jan. 25, 1966, of common ownership wth this application.

A still further sealing arrangement is shown in FIG- URE 7. This is a seal to minimize flow of high pressure fluid through the openings 128 for the drive and idler rollers of the hot side seal bars 126. There is a slight clearance between the seal bar and the matrix rim, and L-shaped roller cavity seal 21 5 is mounted in an L-shaped slot in the face of the seal extending past the low pressure end of opening 128 and alongside of opening 128 to a point near the retainer 153. Seal 215 floats in the slot 216 and is biased into contact with the matrix by compression springs 217 disposed within the slot under the seal 215. This impedes leakage from high pressure through opening 123 and the clearance between the seal bar and matrix to low pressure.

Main seal recapitulation It may be well to review briefly the main seal structure. The main seal is provided to prevent or minimize leakage from high pressure to low pressure at the openings in the bulkhead. It includes a primary seal which is a frame including seal bars extending over the two faces of the matrix and slightly flexible end plates fixed to the seal bars. This structure is mounted to have a slight clearance from the faces of the matrix including the rims, and clearance from the ends of the matrix. The primary seal is supported in a main seal frame 81 made up of the cold side and hot side housings and the end plates which rigidly connect the two housings. The main seal frame in turn is supported by the main support frame 46), which includes the front and rear side plates and three spacers rigidly connecting these plates. The main support frame is fixed in the regenerator case.

The main seal frame is supported in the main support frame by trunnions 98 which define an axis parallel to the matrix axis about which the main seal frame can rotate slightly. Such rotation is controlled by engagement of the aligning or biasing rollers 37 on the cold side housing with the matrix rim. These rollers engage the matrix substantially opposite to the drive and idler rollers which engage the inner face of the matrix rim. The drive and idler rollers are housed within but supported independently of the hot side housings. The seal bars 126 and 127 are held slightly spaced from the matrix by the engagement of

rollers

34, 35, and 37 with the rim. The axis defined by trunnions 98 is located so that the inclination of the seal bars will follow the inclination of the surface of the matrix as it changes in dimension and contour relative to the regenerator case with changes in temperature, pressure, and air flow.

The cold side housing is located in the direction parallel to the matrix axis by a key engaging the main support frame. The hot side seal bar is similarly located, and both the hot and cold side seal bars are deweled to their 9 supporting housings so that they are located relatively axially of thematrix but may extend relative to the housmgs.

The matrix rim is sealed by end shoes 139 rubbing against the matrix rim, these being mounted on and spring biased away from the end plates of the main seal frame. A secondary seal between the primary seal and the main support frame is provided by a sheet metal diaphragm 186 extending around the primary seal frame. Other bypass and miscellaneous seals are provided, which need not be reviewed.

Labyrinth clearance control It may be well at this point to mention a feature associated with the primary seal relating to means for positively maintaining the desired clearance between the labyrinth seal bars of the matrix and the cold side seal bar, which is the invention of Jack P. Hart and myself. A rubbing shoe 220 (FIG. 9) extends circumferentially of the matrix between the two halves of the cold side seal bar 162. This shoe is a bar of tungsten carbide or other hard metal which is disposed to rub against the mid-point of the cold side labyrnith sealing elements of the matrix as they pass through the primary seal. Shoe 220 overlies two

wedges

221 and 222 by which its spacing from the cold side housing 82 may be adjusted. It is retained by two studs 223 threaded into the shoe and passing to the outer surface of the housing where they are retained by nuts 224. One stud 223 passes through a hole in wedge 221 and this wedge additionally is backed up by a shoulder 226 on hte shoe 220. Wedge 222 includes an extension 227 through which an adjusting bolt 229 is disposed. Bolt 229 threads into a somewhat U-shaped bracket 230 which is fixed to the two halves of the seal bar retainer strip 161 at each side of wedge 222. An elongated hole 231 in the wedge permits it to move with respect to bolt 223. By loosening nuts 224, adjusting the wedges, and then tightening the nuts 224, the position of the shoe 220 radially of the matrix with respect to the rollers 37 which ride on the matrix rim may be precisely adjusted. As stated before, this is not a part of the invention of this application but is a concept of Jack P. Hart and myself to which abandoned US. patent application Ser. No. 484,219, filed Sept. 1, 1965 and a continuation-inpart application Ser. No. 653,288, filed June 12, 1967 are directed.

Biasing devices Proceeding now to the structure of biasing devices 123, with reference to FIGURES 2 and 6, each of these devices involves three features; a spring which biases rod 122 into the regenerator case, a piston responsive to pressure inside the case which biases the piston rod out of the case, and a damper which strongly resists any sudden movement of the piston rod from the regenerator case. The biasing device comprises a housing 251 having a flange which abuts a ring 252 which in turn abuts a flange 253 on a cylindrical support 254 extending through the outer wall 30 of the regenerator case. The piston rod 122 passes through the support 254 into the housing 251. Bolts 257 mount the housing 251 and ring 252 on the flange 253. The housing defines a cylinder 258 within which a piston 259 is slidable. Travel of the piston outwardly from the case is limited by a step 261 in the housing to a smaller diameter portion within which is housed a compression spring 262 which biases the piston toward the case. Spring 262 bears against the outer end of housing 251. Piston 259 includes a stem 263 within which is threaded a portion 265 of piston rod 122. The threaded connection provides for adjustment of the position of rod 122 to center the piston in its range of travel determined by the abutment 261 and by an abutment 266 on ring 252. The piston rod 122 terminates in a hexagonal end 267 which may be turned for this adjustment. End 267 normally is covered by a cap 269 on the housing and by a cup-shaped cap 270 bolted to the 1G stem 263. A washer 271 with a hexagonal opening is retained by the cap and bolts 272 so as to positively preserve the adjustment. The piston is held against rotation by a guide pin 274 received in a socket in the piston and slidably received in a socket 275 in the housing.

An oil reservoir 276 is disposed above the chamber 277 on the outer side of piston 259 and is connected to it through a check valve 279 which allows flow from the reservoir into the chamber but not out. A vent plug 280 may be removed to release air from the chamber 277 when the device is filled with oil. The oil filling chamber 276 acts against piston 259 to provide a dashpot effect and resist outward movement. For the piston to move outwardly to any appreciable extent, oil must be expelled through an orifice 281 in the piston.

A seal is provided between the housing and piston by a bellows 283 brazed to ring 252 and fixed to the inner face of the piston by a bolted ring 284. This bellows prevents leakage of compressed air from the regenerator case and leakage of oil into the case. As will be seen, in the normal state of rest of the engine, the piston 259 is disposed between its stops and spring 262 biases rod 122 and thereby biases rollers 37 against the matrix rims. This locates the primary seals and assures a proper frictional loading of the matrix rim against the drive roller and idler roller. When the engine is in operation, there is a substantial force biasing the matrix toward the low pressure side because of the difference between the high and low pressures exerted across the projected cross sectional areas of the matrix where it passes through the main seals and also a force due to the small pressure drop attendant upon flow through the matrix effectively exerted over most of the matrix area. Since it is undesirable to overload the driving rollers, the pressure within the high pressure chamber of the regenerator acts against the area of piston 259 within bellows 283 to oppose the force of spring 262. The total area of the four pistons is suflicient to balance the air pressure forces exerted on the matrix to such extent that the total pressure exerted against the driving and idler rollers does not increase greatly between non-operating and operating conditions.

The buffer or damper is provided because, if a sufficiently severe bump load, as for example due to coupling, is exerted on the locomotive, there is a tendency for the inertia of the matrix to overcome the springs 262 and jolt the matrix away from its supporting rollers. Any substantial movement is strongly opposed because of the very small area of orifice 281 as compared to the area of the piston 259. However, gradual movement of the piston may take place in response to dimensional changes of the matrix.

In this connection, the matrix may expand differently rom the regenerator case during different phases of operation of the engine and during transients and also the effect of pressure on the matrix is to distort it slightly from its normal circular shape to a slightly egg-shaped contour. Movement of the piston rod 122 can accommodate these changes. The movement of the main seal frame about its trunnions 98 permits the primary seal to align itself properly with the matrix notwithstanding the substantial extent of the seal and the very small radial clearance. The small radial clearance is, of course, necessary to minimize leakage through a labyrinth seal of this sort. While such variations in size might not be significant in a very small structure, the present embodiment of my invention is in a regenerator having a drum 74 inches in diameter, 46 /2 inches wide, and with a core thickness of 4 inches. With this structure, it is desirable to maintain a clearance or .010 inch on the cold side and .030 inch on the hot side under normal hot running conditions. The effective width of the primary seal bars is approximately 6 inches, and these cooperate with eleven labyrinth seal strips of the matrix at one time. In this particular regenerator the change in slope of the rims at the point of the hot side roller contact amounts to about one-sixth degree, which calls for a movement of the pistons 259 of about .020 inch.

Conclusion It should be apparent to those skilled in the art that the principles of my invention, as exemplified by the described embodiment, are particularly favorable to successful employment of regenerators, including those of large size and those in moving vehicles such as locomotives.

The invention is particularly adapted to solve problems of supporting, driving, and sealing such devices while allowing for relative expansion and distortion of parts.

Many modifications may be made within the scope of the invention by the exercise of skill in the art.

What is claimed is:

1. A rotary regenerator comprising, in combination,

a case including a bulkhead dividing the interior of the case into two chambers,

a radial-flow annular matrix disposed partly in each chamber, the bulkhead defining two openings for the matrix,

the matrix having inner and outer faces and having rims at the ends of the matrix, and having heat transfer structure pervious to fluid flow from face to face between the rims,

two matrix support rollers rotatably supported on the case in position to engage the inner face of the matrix rim, each roller being closely adjacent to one of said openings so that the matrix is radially located at the said openings by the support rollers,

means for driving one of said rollers so as to rotate the matrix by friction between the roller and rim,

a main seal mounted on the bulkhead at each said opening encircling the matrix and adapted to minimize leakage between the chambers,

a biasing roller movably mounted adjacent each support roller and adapted to engage the outer face of the matrix rim opposite the support roller, and

biasing means urging the aligning rollers into contact with the matrix and thus biasing the matrix against the support rollers.

2. A regenerator as defined in claim 1 including also 'dashpot means associated with the biasing means resisting rapid movement of the biasing roller away from the support roller resulting from shocks affecting the matrix.

3. A regenerator as defined in claim 1 in which the fluid flow is such that the inner face of the matrix is the hotter face.

4. A regenerator as defined in claim 1 in which the biasing roller is mounted on the main seal, and the main seal is mounted to 'tilt about an axis parallel to the axis of rotation of the matrix.

5. A regenerator as recited in claim 1 including damping means associated with the biasing means adapted to resist movement of the biasing rollers away from the support rollers as a result of shocks affecting the matrix.

6. A regenerator as recited in claim 1 including means responsive to a condition indicative of pressure in the regenerator effective to reduce the biasing effect as gas pressure loads on the matrix increase.

7. A rotary regenerator comprising, in combination,

a rotatably mounted matrix having first and second faces and including heat transfer structure pervious to fluid flow from face to face,

the matrix including at least one rigid rim extending from face to face of the matrix,

a driving roller frictionally engaging the rim at one face,

a biasing roller mounted for movement toward the rim at the other face substantially opposite to the drive roller, and

means for urging the biasing roller against the rim so as to grip the rim between the rollers and provide traction between the driving roller and the matrix.

8. A regenerator as recited in claim 7 in which the matrix has two rims and there are driving and biasing rollers engaging both rims.

9. A regenerator as recited in claim 7 in which the driving roller is at the hotter face of the matrix.

10. A regenerator as recited in claim 7 in which the matrix is of a radial-flow type having two coaxial rims and a driving roller and a biasing roller engage each rim.

11. A rotary regenerator comprising, in combination,

a radial-flow annular matrix disposed partly in each chamber, the bulkhead defining openings for the matrix,

two matrix support rollers rotatably supported on the case in position to engage the same face of the matrix, each roller being closely adjacent to one of said openings so that the matrix is radially located at the said openings by the support rollers,

a main seal support at each opening defining an outer frame extending around the matrix,

means mounting the frame for rotation about a frame axis adjacent the support roller and substantially parallel to the matrix axis,

a pressure roller mounted on the frame engaging the matrix substantially opposite the support roller,

means biasing the frame about its axis so as to grip the rim between the support and pressure rollers,

means connecting the outer frame to the case so as to locate the frame axially of the matrix,

a primary seal mounted in the main seal support and defining an inner frame extending around the matrix and adapted to provide with the matrix a seal between the chambers,

means connecting the inner frame to the case independently of the outer frame operative to locate the inner frame axially of the matrix,

and a secondary seal concentric to the frame axis sealing between the inner frame and the case.

References Cited UNITED STATES PATENTS 2,893,699 7/1959 Bubniak l65-9 X 3,014,703 12/1961 Jones 9 3,043,568 7/1962 Koltholf 1659 X 3,057,604 10/1962 Bubniak et a1 1659 3,162,241 12/1964- Smith 1659 3,216,487 11/1965 Gallagher 165-9 3,267,674 8/1966 Collman et al 165-9 X ROBERT A. OLEARY, Primary Examiner.

A. W. DAVIS, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,384,156 May 21, 1968 Albert N. Addie It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 14, "the" should read to Column 4, line 33, "oily" should read oil line 55, "previous" should read pervious Column 6, line 20, "having" should read have Column 7, line 70, "pm Mons" should read portion Column 9, line 2, "extend" should read expand line 31, "hte" should read the A Signed and sealed this 10th day of March 19 NJ.

(SEAL) Attest:

Edward M. Fletcher, Jr. E.

Attesting Officer Commissioner of Patents