US2738958A

US2738958A - Regenerative heat exchanger

Info

Publication number: US2738958A
Application number: US282247A
Authority: US
Inventors: Hodge James
Original assignee: Power Jets Research and Development Ltd
Current assignee: Power Jets Research and Development Ltd
Priority date: 1951-04-24
Filing date: 1952-04-14
Publication date: 1956-03-20
Anticipated expiration: 1973-03-20

Description

March 20, 1956 J. HODGE 2,738,958

REGENERATIVE HEAT EXCHANGER Filed April 14. 1952 2 Sheets-Sheet 1 (men far A J. HODGE REGENERATIVE HEAT EXCHANGER March 20, 1956 2 Sheets-Sheet 2 Filed April 14, 1952 REGENERATIVE HEAT EXCHANGER James Hodge, Farnborough, England, assignor to Power Jets (Research & Development) Limited, London, England, a British company Application April 14, 1952, Serial No. 282,247

Claims priority, application Great Britain April 24, 1951 11 Claims. (Cl. 257-6) This invention relates to regenerative heat exchangers having a body known as a matrix incorporating heatstoring material through which flow in separate streams fluids between which heat is to be exchanged, ducting to lead fluid to and from the matrix, and means for effecting relative rotational movement between matrix and ducting so that difierent parts of the matrix are successively traversed by each fluid. The relative rotational movement may be effected by employing a rotary matrix or alternatively by using ducting or the like which rotates in relation to a non-rotary matrix.

There are two main types of such regenerators namely that of which the matrix is in effect a disc through which the fluids pass in a generally axial direction, and that of which the matrix is a hollow drum through which the fluid passage is generally radial.

It is a problem in such devices to provide seals defining the area of matrix through which each of the fluids is to pass and preventing excessive fluid leakage at the junction between matrix and ducting. It has been proposed for such seals to be in effect frames, in frictional rubbing contact with the matrix, enclosing the flow of.

one fluid by acting as the complementary ends of two ducts, one leading that fluid to and the other from the matrix. The relative rotational movement between seals and matrix causes Wear of the seals and/ or of the matrix, and it is desirable that such Wear should not impair satisfactory mating between the sealing surfaces; in other words it is desirable that the sealing surfaces be properly lapped. It is to that object that the present invention is primarily directed.

The present invention accordingly provides a regenerative heat exchanger having a heat-storing matrix through which flow in separated streams fluids between which heat is to be exchanged, seals, non-rotatable about their own axes, which bear frictionally against the matrix and en close the area of matrix through which one of the fluids is to pass, means for eifecting relative rotational movement between matrix and seals so that the seals sweep a circular locus over the matrix surface whereby different parts of the matrix are successively traversed by each fluid, characterized by means whereby during operation of the heat exchanger such relative motion is established between seals and matrix, in a direction transverse to the direction of said rotational movement, as will promote satisfactory mating between the sealing surfaces.

The relative motion in the transverse direction is preferably provided by means'which ensure that, in the course of the relative rotational movement between matrix and seals, any point on the rubbing surface of a seal does not contact the same point on the matrix except after completion of more than one revolution about the circular locus. Thus, in a case where the relative rotational movement is provided by using a rotary matrix, the seals may be moved transversely across the path of the matrix in a cyclic manner which has a fractional difference from the cycle of rotation of the matrix. So that, for example,

nited States Patent in revolutions of the matrix the seals may only perform 99 cycles of their own motion.

The relative motion in the transverse direction may be oscillatory in character, for example a linear oscillation. If it is the seals which oscillate, they may be pivoted so that the oscillation is arcuate about the axis of pivot.

In a case where a non-rotary matrix is used in combination with seals, acting as duct ends, which move in a circular locus over the matrix, the relative motion in a transverse direction (for lapping the seal) may be imparted to the matrix, for example by giving it a linear oscillation.

By way of example various embodiments of the invention will now be described in more detail and with reference to the accompanying drawings in which:

Figure l is a transverse section on the line II in Figure 2, through a regenerator according to the invention.

Figure 2 is an axial section on the line II-II in Figure 1.

Figure 3 is a transverse section showing diagrammatically a different embodiment of the invention.

Figure 4 is a similar transverse section showing a further embodiment.

Figure 5 is an axial section of still another embodiment of the invention.

Figure 6 is a transverse section of the embodiment shown in Figure 5.

The heat exchanger shown in Figures 1 and 2 comprises a casing 1 within which is mounted for rotation a disc-like matrix consisting of a hub portion 2 and a rim portion 3 containing between them the effective heat storing portion 4 which is pervious to fluid flow and in the present instance may be considered as comprising a pack of tubes 5 which constitute individual passages for fluid flow. The matrix is mounted on a shaft 6 by which it is rotated.

In the present case the heat exchanger is one suitable for exchange of heat between two streams of gas at substantially different temperatures and pressures. The ducting for leading these gases to and from the matrix comprises in the first place ducts 7 on each side of the matrix registering with each other and being of sectorlike cross section adjacent the matrix but for convenience merging to cylindrical section further away from the matrix. The sector shape may be modified by substituting involute curves for the straight radial walls since in some cases they may have practical advantages in operation. The complementary ends of the ducts 7 are defined by frame-like seals 8 of sector like shape one on each side of the matrix. These sealing elements are urged against the matrix surface by spring means (not shown) and/ or by the effect of gas pressure in the duct 7. The cooler gas, in this case assumed to be at a high pressure, for example several atmospheres, is conveyed to and from the matrix by way of the ducts '7 to prevent leakage of such gas into the other gas stream is the purpose of the seals 8 which are accordingly urged against the matrix with suflicient pressure to substantially prevent such leakage. The seals 3 are made of any suitable material for example self-lubricating material or" a graphitic nature, and are subject to wear by their rubbing contact with the rotary matrix.

Thus it will be seen that the seals 8 define the area of matrix through which the cold high pressure gas is to pass. The hotter gas which is at lower pressure than the other, flows in the space 9 defined by the casing 1 and thus has access to that area of the matrix which is complementary to the area defined by the seals 8. These latter for a reason which will appear later are connected to the ducts '7 by bellows 10 permiting lateral movement of the seals relative to the ducts 7. To prevent the hot 3 gasfrom by-pas'sing the matrix altogether a circular labyrinth seal is provided at 11.

As the matrix rotates the seals 8 sweep a circular locus over the matrix surface so that different parts of the matrix are successively traversed by the hot gas and the' cold gas alternatively andheat abstracted by the matrix from the" hot gas is-transferred to the cold gas.

To ensure good sealing it is importantthat the'sealing surfaces be properly lapped and that the wear of the seals 8g and. any wear of the matrix, should be as far as possible uniform. To this end the seals 8 are given a linear oscillation radially across the rotating matrix. The shaft Ghas fixed to it two pinions' 12 each of which engages with and drives an internally toothed annulus 13 whiehrests on and is supported by the 'pinion. The annulus 13 is provided with an outer rim which is eccentric to the axis about which the annulus rotates and as shown in" the: drawing each seal 8has an internal extension 14 which rests upon the outer rim'oftheadjacent annulus, the extension 14 being arcuately shaped for this purpose. Thus as the annulus 13 rotates the seals 8 will oscillate up and down by the cam effect of the annulus. A cover plate'lfi is fixed to each seal structure to enclose the gearing and is provided with a slot 16 through which passes the shaft 6 and which slot may be' provided with some form of sealing toprevent entry of hot gas;

Each seal element 8 is furnished with radially extending

rods

17, 18 having plungers such as 19 at their ends which are free to slide in cylindrical sockets 21 provided in the heat exchanger casing 1. The upper rods 17 bear against compression springs 20 in the sockets 21. The

rods

17, 13 act as guides for the seals so that their oscillation is in a radial direction the spring 20 serving to return the seal positively after the upward movement. The relatively small amount of seal oscillation provided is sufficient for the purpose in view.

As the

gearing

12, 13 provides a speed reduction the cyclic oscillation of the matrix has a difference from the cycle of rotation of the matrix so that a particular point on the rubbing surface of a seal does not contact the same point on the matrix except after a number of revolutions of the latter.

Figure 3' represents an alternative embodiment of the invention in which the basic structure is the same as Figure 1 in that there is a rotatable matrix with a heat storing portion 4 operating within the casing 1 and that frame like seals 8 define the ends of the high pressure gas ducts. In this case, however, each sealis pivoted at 22 and by means of an external crank or eccentric 23 connected by rods 24 to the seal the latter receives a small arcuate oscillation about the pivot 22. This arouate movement involves a component of motion across the path of the matrix which is sufficient for lapping purposes. It will be appreciated that there may be instantaneous conditions in which the seal will be locally stationary relative to the matrix and others when it will move in the same direction. There are two eccentrics 23 each connected to one of the seals so that both these latter are moved simultaneously and exactly similarly. The shaft carrying the eccentrics or cranks 23 rotates at a slight speed difference from the shaft 6.

Figure 4 relates to a further embodiment in which the seals are again pivoted as at 22. In this case, however, each seal is connected to a tension spring 33 housed within a socket 34. The matrix is rotated in the direction indicated by the arrow and the strength of the spring 33 in relation to the friction between seal and matrix is such that the frictional drag of the matrix moves each seal a short distance about the pivot 22 until the spring 33 overcomes this movement and returns the seals to the original position. Thus a random arcuate oscillation of the seals is provided.

Figures and 6 illustrate the application of the invention to a case where the matrix is non-rotary and the desired relative rotational movement between matrix and ducting is achieved by rotating the ducts 7 so that their ends which are defined by the seals 8 sweep in a circular locus over the surface of the matrix. The ducts 7 each comprise a non-rotary cylindrical portion 27 and a portion 28 bent as shown which at one end is cylindrical in section and forms a joint- 29' which permits rotation of the part 28 the other end of which is sector like and enclosed'by the seals 8. By means, not shown, the parts 28 are rotated,- extreme positions being shown in Figures 5 and 6 infull and broken lines respectively. The means for effecting such rotation may'consist of a gear drive by way of a pinion engaging an externally toothed annulus which is attached by webs to the duct portions 28. To provide the necessary lapping motion transverse to the circular locus of the ducts 28 the matrix itself is mounted for slight oscillatingmovement across the duct 1. Such movement is provided by means of four cams 31 on which the matrix rests, these cams being carried by shafts 30 mounted side by side. Each shaft 30 carries two cams 31. To provide the desirable cyclic difference between the oscillation of tliematn'x and the rotation of the ducts 28 there is a rotational speed difference between the ducts 28 and the shafts 30. Toprevent by-passing of the hot gas past the matrix while at the same time not obstructing the oscillation of the latter bellows or the like 32 are provided between the matrix and the casing 1.

Reverting to more general matters from the above embodiments described in detail, it should be noted as a possible modification that the transverse seal-lapping motion may be imparted to the rotary body, whether matrix or seals. Thus, if the matrix for example rotates relative to non-rotary ducting, the desired lapping. effect may be ensured by giving a transverse oscillation to the matrix, in addition to its rotation.

What I claim is:

l. A rotary regenerative heat exchanger comprising a heat storing matrix, said matrix having two opposed surfaces, means defining flow paths between said surfaces for the separated fiow of the fluids between which heat is to be exchanged, seals, ducting for conducting fluids to and from the matrix through said seals, said seals bearing frictionally against said opposed surfaces of the matrix for isolating the region of thematrix through which one of the fluids is to pass from the remainder of the matrix, means for effecting relative rotational movement between the matrix and the seals so that the seals sweep a circular locus over the said opposed matrix surfaces whereby different parts of the matrix are successively traversed by fluid, and means acting concurrently with the relative rotational movement effecting means for producing relative oscillatory motion between the matrix and the seals, the said motion having a component in a direction radially of the matrix.

2. A rotary regenerative heat exchanger comprising a heat storing matrix, said matrix having two opposed surfaces, means defining flow paths between said surfaces for the separated flow of the fluids between which heat is to be exchanged, seals, ducting for conducting fluids to and from the matrix through said seals, said seals bearing frictionally against said opposed surfaces of the matrix for isolating the region of the matrix through which one of the fluids is to pass from the remainder of the matrix, means for effecting relative rotational movement between the matrix and the seals so that the seals sweep -a circular locus over the said opposed matrix surfaces whereby different parts of the matrix are successively traversed by fluid and means for relatively oscillating said matrix and seals in a path having a component radial of the matrix at a frequency in relation to the speed of said relative rotational movement such that the relative rotation effecting means causes at least one revolution of said seals and opposed surfaces of said matrix around said circular locus before any point on a seal twice contacts the same point on the opposed surface against which it bears.

3. A rotary regenerative heat exchanger comprising a heat storing matrix, said matrix having two opposed surfaces, means defining fiow paths between said surfaces for the separated flow of the fluids between which heat is to be exchanged, seals, ducting for conducting fluids to and from the matrix through said seals, said seals bearing frictionally against said opposed surfaces of the matrix for isolating the region of the matrix through which one of the fluids is to pass from the remainder of the matrix, means for effecting relative rotational movement between the matrix and the seals so that the seals sweep a circular locus over the said oposed matrix surfaces whereby different parts of the matrix are successively traversed by fluid and means acting concurrently with the relative rotational movement eifecting means for relatively oscillating said matrix and seals in a linear path having a component radial of the matrix.

4. A rotary regenerative heat exchanger comprising a heat storing matrix, said matrix having two opposed surfaces, means defining flow paths between said surfaces for the separated flow of the fluids between which heat is to be exchanged, seals, ducting for conducting fluids to and from the matrix through said seals, said seals bearing frictionally against said opposed surfaces of the matrix for isolating the region of the matrix through which one of the fluids is to pass from the remainder of the matrix, means for effecting relative rotational movement between the matrix and the seals so that the seals sweep a circular locus over the said opposed matrix surfaces whereby different parts of the matrix are successively traversed by fluid and means acting concurrently with the relative rotational movement effecting means for relatively oscillating said matrix and seals in an arcuate path having a component radial of the matrix.

5. A rotary regenerative heat exchanger comprising a disc-like heat storing matrix, said matrix having two opposed surfaces, means defining flow paths between said surfaces for the separated flow of the fluid between which heat is to be exchanged, seals, ducting for conducting fluids to and from the matrix through said seals, said seals being of substantially sector shape and bearing frictionally against the said opposed surfaces of the matrix for isolating the region of the matrix through which one of the fluids is to pass from the remainder of the matrix, means for effecting relative rotational movement between the matrix and the seals so that the seals sweep a circular locus over the said matrix surfaces whereby diiferent parts of the matrix are successively traversed by fluid, and means acting concurrently with the relative rotational movement eifecting means for producing relative oscillatory motion between the matrix and the seals, the said motion having a component in a direction radially of the matrix.

6. A rotary regenerative heat exchanger comprising a disc-like heat storing matrix, said matrix having two opposed surfaces, means defining flow paths between said surfaces for the separated flow of the fluids between which heat is to be exchanged, seals, ducting for conducting fluids to and from the matrix through said seals, said seals being of substantially sector shape and bearing frictionally against the said opposed surfaces of the matrix for isolating the region of the matrix through which one of the fluids is to pass from the remainder of the matrix, means including a rotatable shaft for supporting the matrix for effecting relative rotational movement between the matrix and the seals so that the seals sweep a circular locus over the said matrix surfaces whereby different parts of the matrix are successively traversed by fluid, and means acting concurrently with the relative rotational movement efiecting means for producing relative oscillatory motion between the matrix and the seals, the said motion having a component in a direction radially of the matrix.

7. A rotary regenerative heat exchanger as claimed in 7 claim 6 in which the said means to produce the oscillatory motion comprises an internally toothed gear annulus having an eccentric rim upon which the apices of the substantially sector-shaped seals rest and a reduction gear mounted on the matrix shaft for driving the said annulus,

seals are freely pivotable and resilient means for biasing the seals about the pivots in one direction, arcuate oscillatory motion being effected by the matrix which, as

it rotates, moves the seals by frictional drag against the biasing means until the latter overcomes the drag and returns the seals to their initial positions.

9. A rotary regenerative heat exchanger as claimed in claim 6 in which the means to produce oscillatory motion comprise pivots about which the said sector-shaped seals are freely pivotable, eccentrics mounted externally of the heat exchanger and rods connecting the said eccentrics to the said seals.

10. A rotary regenerative heat exchanger comprising a heat storing matrix, said matrix having two, opposed surfaces, means defining flow paths between said surfaces for the separate flow of fluids between which heat is to be exchanged, seals, ducting for conducting fluids to and from the matrix'through said seals, said seals bearing frictionally against the said opposed surfaces of the matrix for isolating the region of the matrix through which one of the fluids is to pass from the remainder of the matrix, means for positively rotating the seals with respect to the matrix so that the seals sweep a circular locus over the matrix surfaces whereby different parts of the matrix are successively traversed by each fluid and means for imparting to the matrix an oscillatory motion, the said motion having a component in a direction radially of the matrix.

11. A rotary regenerative heat exchanger comprising a heat storing matrix, said matrix having two opposed surfaces, means defining flow paths between said surfaces for the separate flow of fluids between which heat is to be exchanged, seals, ducting for conducting fluids to and from the matrix through saidseals, said seals bearing frictionally against the said opposed surfaces of the matrix for isolating the region of the matrix through which one of the fluids is to pass from the remainder of the matrix, means for positively rotating the seals with respect to the matrix so that the seals sweep a circular locus over the matrix surfaces whereby different parts of the matrix are successively traversed by each fluid and means for im-' parting linear oscillatory motion to said matrix, said motion having a component radial of the matrix.

References Cited in the file of this patent UNITED STATES PATENTS