US2797498A - Heat exchangers - Google Patents

Description

July 2, 1957 I R. JlPP I 2,797,498

' HEAT EXCHANGERS I Filed March 31, 1954 s Sheets-Sheet 1 Filed March 51. 1954 R. JIPP HEAT EXCHANGERS I 5 Shets-Shaet? Inventor? 5 Sheets-Sheet 3 o f. 0 o, v

R. JIPP H E AT EXCHANGERS July 2, 1957 Filed March 31, 1954 July 2, 1957 JIPP 2,797,498

I HEAT EXCHANGERS Filed March 31, 1954 5 Sheets-Sheet 4 Inventor: I E? J/ PP R. JlPP HEAT EXCHANGERS July 2, 1957 5 Sheets-Sheet 5 Filed March 31, 1954 A 2,797,498 Patented July 2, 1957 HEAT EXCHANGERS.

Rolf Jipp, Lubeclr-Travemunde, Germany, assignor to Maschinenfabrik Beth Aktiengesellschaft, Lubeck, Germany Application March 31, 1954, Serial No. 420,168

. Claims priority, application Germany May 7, 1953 11 Claims. (Cl. 34-164) The present invention relates to a heat exchanger, and particularly to a heat exchanger forexchanging heat between a solid granular material and a fluid.

It'is an object of the present invention to provide a I device of the 'kind described which allows the heat exchange to be carried out under vacuum.

it is another object of the present invention to provide and dry solid granular materials having :a range of grain 7 sizes between and 150 millimeters.

In a preferred embodiment of the present invention several vertical tubes are arranged in a circle and several helical screw-shaped members are arranged, respectively, in the vertical tubes, the material to be treated being consecutively fed by a revolving distributing device or the like to the vertical tubes.

Other objects and advantages of the present invention will become apparent from the following detailed description thereof when read in connection with the accompanying drawings showing, by way of example, some embodiments of the present invention. In the drawings Fig.1 is a vertical section of a first embodiment of the present invention;

Fig. 2 is a cross section taken along the line AB shown in Fig. 1; i

Fig. 3' is a longitudinal section, partly in elevation, of

shaped pipe 8 is continued by a pipe 10 secured to a ringshaped member 9 rotatable about the middle axis thereof and provided on the lower side thereof with a toothed rim 11 engaging a pinion 13 driven by an electric motor 12 carried by a projecting part 12 of the upper part 1'. of the casing 1 connected therewith by flange-like parts in.

Within each of the vertical tubes 4 is arranged a vertical helical screw-shaped member 16 consisting of a plunality of sections such as 16, 16", 16", etc. forming a series and being separated from one another by gaps such as 16a and 16b. The upper edge 160 of the uppermost section 16 is horizontal as will be seen from Fig. 1. The helical screw-shaped members 16 are secured to carrying rods which are suspended by one-armed levers 1'7 swingable about stationary members such as 17 and having free ends carrying rollers 18 being in contact with the upper surface of the ring-shaped member 9 which is provided with one or more cams 19 for imparting to the rods 15 impact-like lifting and lowering movements. a

A connecting pipe 20 is provided in the upper part of the casing 1 whereas another connecting pipe 22 is provided in the lower part of the casing 1 and connected by I21 bend or elbow 2.3 to a connecting pipe 24 connected to the pipe 7.

The chamber 2 enclosed by the casing 1 is provided with a plurality of horizontally arranged bafiies nor the like having edge portions such as 21a and 2112 which are parallel to one another and turned downwards so as to impart a zigzag flow to the fluid flowing downwardsin the casing l. The upper part of the casing 1 is separated from the upper part i by a conical wall 1d. The upper part 1' of the casing 1 communicating with the interiors of the tubes 4 is provided with an elbow piece 25 serving as an outflow for the gaseous components of the reactions.

a second embodiment of the present invention;

Fig. 4 is a cross section on an enlarged scale of a third embodiment of the present invention;

Fig. 5 is a side elevation, partly in section, of a slightly modified embodiment such as that shown in Fig. 3, in connection with some additional devices;

Fig. 6 is a section of :a modified detail;

Fig 7 is a longitudinal section, partly. in elevation, of a further embodiment of the present invention; and

Fig. 8 is a plan view of the device shown in Fig. 7.

Referring now to the drawings and first to Figs. 1 and 2, the heat exchanger includes a casing 1. having a vertical axis 3 (Fig. 2) about which are concentrically arranged a plurality, for instance eight substantially vertical tubes 4 secured to an upper plate 5 and a lower plate 6. The

plates 5 and 6 delimit a chamber. 2, forming the interior of the casing 1 and containing the tubes 4. A pipe 7 is connected to the lower plate 6 by a frusto-conical part 7 In the upper part 1 of the casing 1 above the upper plate 5 an elbow-shaped pipe 8 is arranged which revolves so as to come into operative connection consecutively with the upper ends of the vertical tubes' i. The elbow- The operation of this device is as-follows:

The solid granular material is conveyed through the pipe 14' provided with a conveying screw 14 to the en? trance of the pipe It). At the same time the electric motor 12 is put into operation so that the ring-shaped member 9 is rotated and imparts a rotation to the pipe 10 and the elbow-shaped pipe 8 connected thereto so that the latter delivers the granular material to the upper ends of the tubes 4 one after the other. Furthermore the cam 19 lifts the rollers 18 of the one-armed levers 17 one after the other, so that the rods 15 carrying thescrews 16 are imparted vertical oscillatory movements in substantially vertical I directions. Thus the granular solid material conveyed by the screw 14 and dropping down through the pipe 10 is supplied consecutively to the tubes 4'containing the screw-shaped members 16 undergoing a vertical oscillatory movement in the manner described hereinabove so that the granular material will be conveyed downwards by the sections such as 16, 16",16", etc. of the helical screweshaped members 16.

At the same time, a fluid such as preheated gas intended to dry the solid granular materialis admitted by the connecting pipe 20 and is imparted a zigzag flow in the chamber 2 by the bafiies 21. .After flowing through the chamber Zthe gas flows through the connecting pipe 22, the elbow 23, and the connecting pipe 24 into the pipe. 7 and upwards through thefrusto-conical part-7' closed at its upper end by the lower plate 6 into the tubes 4 which it traverses in upward direction so as to enter the upper part 1' of the casing 1 from which the gas is discharged by the elbow piece 25. e

The solid granular material leavingthe screw-shaped members 16 and the tubes 4 enclosing the same are transported by the frusto-conical part 7', and the pipe 7 in the direction of the arrow shown in full lines in Fig. 1,

are supplied, if desired, to a sluice (not shown) or the like, and are finally discharged. The path of the gas is indicated in Fig. 1 by the arrows shown in broken lines. It should be noted that the gas passes through the tubes 4 along screw-shaped paths imparted to the same by the screw-shaped members 16. If desired, a fan (not shown) may be connected to the elbow piece 25.

The screw-shaped paths through the tubes 4 cause the heat carrier (gas) to come into effective contact on a large surface and at a favorably retarded rate with the granular solid material sliding downwards along the sections such as 16', 16", 16", etc. of the screw-shaped members 16. In consequence thereof, the gas yields the heat contained therein to the solid material so as to evaporate or to volatilize the moisture contained in the solid material and to preheat the same.

The quantity of the solid material may be controlled, if desired, by controlling the speed of the revolving movement of the ring-shaped member 9 driving the pipe 10 by adjusting the speed of the electric motor 12.

Furthermore the height of the projection or projections 19 of the ring-shaped member 9 can be made adjustable by adjusting means (not shown) so as to adjust the amplitude of the movements of the helical screw'shaped members 16 with respect to the tubes 4.

Furthermore to the helical screw-shaped members 16 can be imparted instead of an oscillatory movement a rotatory knocking movement. Furthermore the electric motor 12 may be provided with means such as resistors (not shown) for changing in stages the number of revolutions thereof so that the number of movements, for instance vertical oscillatory movements of the helical screwshaped members 16 per unit time can be arbitrarily controlled.

Referring now to Fig. 3 of the drawings a dust chamber 31' is provided with a ceiling 31 forming the bottom wall of a chamber 32" having a cylindrical side wall portion 32 provided on its inner side with a structure 32' consisting of refractory stones. The ceiling 33 of the chamber 32' carries a plurality of vertical tubes 34 consisting preferably of a ceramic material. The tubes 34 are provided with helically screw-shaped members 35 carried by rods 36, respectively. The screw-shaped members 35 may be subdivided into sections, such as 16', 16", etc. shown in Fig. l, and may be alternately lifted and lowered, and/ or rotated, the lifting and lowering movement being caused by rods such as 36 driven by the gearing 36', 36", the gear wheel 36" being rigid with the pipe 37 connected to the elbow-shaped pipe 37 corresponding to the pipe 10 and the elbow-shaped pipe 8 shown in Fig. l. The pipe 37' is connected to a screw conveyor 60 driven by an electric motor 61 and conveying the solid granular material to the pipe 37'. The gear wheel 36" is driven by a bevel gear 38' driven by the electric motor 38. Below the lower ends of the tubes 34 and within the chamber 32' a funnel 39 is arranged which is preferably suspended by members such as 39" from the ceiling 33. The funnel 39 has an upper diameter so that it catches any material subjected to a treatment within the tubes 34, and it discharges the same through a vertical tubeshaped part 39 extending through an opening 42 in the bottom wall 31. The material is conveyed by the part 39' to a chute 40 which supplies the same to a rotating cylindrical kiln or the like.

The gas enters through an inlet (not shown) the dust chamber 31' from which it escapes through the opening 42 in the ceiling 31 through which the part 39 extends without filling it. After. leaving the wide opening .42 the hot gases pass around the. funnel 39 and enter the pipes 34 in which they act upon the solid granular material such as raw powdered cement flowing downwards in counterflow. The gases leave the device through the upper part 48 designed as a hollow ring-chamber and arranged above the pipes 34.

In the embodiment shown in Fig. 4 a metal part or casing 401 is provided on its inner wall with a heat insulation 402 which encloses sectorlike structures 403 provided with internal hollows 404 forming vertical tubes. The hollows are the analogs of the tubes 34 shown in Fig. 3.

The structures shownin Figs. 3 and 4 allow an essential simplification of the heat exchanger and a better supervision and inspection thereof due to the insulation of the tubes against the casing, or, if the tubes are manufactured from ceramic material, or are built up separately from fire-proof stones as shown in Fig. 4, due to the arrangement below the bottom of the heat exchanger of a collecting funnel as shown in Fig. 3, for passing on the treated material, and the provision adjacent to the funnel of openings through which the treating fluids enter.

If such a heat exchanger is intended for the treatment of raw pulverized cement in cement factories, the heat exchanger may be arranged, as shown in Fig. 5 of the drawings, immediately on the ceiling wall of a dust chamber thus decreasing essentially the overall height of the plant. In Fig. 5 the heat exchanger is essentially de signed as in Fig. 3 and includes the cylindrical lower portion 32, the tubes 34, the upper part 43, and the pipe 37 which is connected in this case to a conical intermediate part or separator 37" and a cyclone 47 more fully to be described hereinafter. The heatexchanger stands on the floor 31 which forms the ceiling of the dust chamber 31 and is provided with an opening 42 through which the vertical tube-shaped part 39' of the funnel (not shown) extends. The part 39' leads the solid material over the chute 40 to the rotating cylindrical kiln 41 or the like. The lower part of the heat exchanger including the lower portion 32 in which the funnel (not shown) is arranged consists preferably of ceramic material or is lined with fire-proof bricks or stones.

In order to decrease the overall height of the heat exchanger and the parts connected thereto the supply bin or silo 45 containing the solid granular material to be delivered to the heat exchanger is also arranged on the floor 31 and connected with the heat exchanger by a device 52 for withdrawing predetermined quantities of solid material from the storage bin 45, and a pneumatic conveying pipe 46 which conveys a mixture of air and solid material in the direction of the horizontal arrows M and N to the cyclone 47 connected to the conical part or separator 37". The air is driven through the pipe 46 by a fan (not shown). From the cyclone 47 the mixture of air and solid material enters into the conical part or separator 37 in which the solid material is separated from the air which is discharged at the upper end of the cyclone 47 in direction of the arrow 0. Preferably hot air is used as conveying air so that the solid materials withdrawn from the silo 45 are preheated while they pass through the conveying pipe 46.

If desired, the tubes 4 shown in Figs. 1 and 2, and 34 shown in Figs. 3 and 5, may have a non-circular cross section, for instance a rectangular, square, or polygonal cross section. Furthermore the tubes may be arranged in a plurality of concentric circles, squares, or polygons.

Referring now to Fig. 6 of the drawings the tubes such as 634 containing the helical screw-shaped members (not shown) are provided with one or more short feed pipes or nipples such as 48, 49, 50, and 51, through which a gaseous, liquid, or solid substance, or a combination of the same may be conveyed and added to the solid material traveling through the tubes 634 from the top to the bottom. The materials passing through the feed pipes 48-51 and leaving the same in direction of the curved arrows may be periodically changed, if desired, so that the solid material passing through the tubes such as 634 is periodically subjected to different treatments.

Referring now to Figs. 7 and 8 of the drawings, showing a modification of the device shown in Fig. 1, a continuously variable transmission gearing 100 of a design well known per se in the art, is arranged between an electric motor (not shown) corresponding to the electric motor 12 shown in Fig. 1, and a gear wheel 107 driving a toothed rim 111 formed on the outside of a wheel 112 to be described more in detail hereinafter. The toothed rim 111 is connected to a part 109 which is in rigid connection with the pipe 110 forming the common upper part of the elbow-shaped pipes 108 and 108' arranged diametrically opposite to each other.

The wheel 112 is made in one piece with a rim-like structure 113 carrying on its outer perimeter a plurality of cams 105 engaging, respectively, the ends of levers 101 acted upon, respectively, by pressure springs 104 supported by preferably adjustable members 114 by the adjustment of which the pressures can be changed which are exerted by the springs 104 on the levers 101. The latter are rigidly connected, respectively, with the shafts 102 of the helical screw-shaped members 103 designed as multiple, for instance double screws.

The operation of this device is as follows:

When the toothed wheel 107 is rotated by the transmission gearing 100 driven by the electric motor (not shown), the wheel 112 rotates and, therefore, the rimlike part 113 thereof carrying the cams 105 is rotated in the direction of the arrow R shown in Fig. 8. During the rotation the cams 105, the number of which is somewhat lower than the number of the levers 101, come into engagement with the latter. In the position shown in Fig. 8 the cam 105 is on the point of engaging the ballshaped head 115 of one of the levers 101 Whereas the cam 105" has just passed under the head 115 of the following lever 101. Thus it is seen that the levers one after the other are at first pressed backwards against the force of the springs 104 by the cams such as 105 until the rimlike part 113 has moved further so that the cam 105' comes into a position relative to the head 115 which is shown in Fig. 8 for the cam 105" and the head 115'. In consequence thereof the lever 101 which had first moved in the direction of the arrow S thereby compressing the spring 104 is now moved in the direction of the arrow T until the lever 101 collides with a stop member 105. By this sudden change of direction of the movement of the levers 101 the latter exert impulses on the shafts 102 of the helical screw-shaped members 103, respectively, and the energy transmitted to the same causes the dry granular material to move downwards along the turns of the helices 103 towards the lower end (not shown) of the helices. The latter are wound in a direction corresponding to the direction in which the levers 101 strike the stop members 106. The energy of the strokes may be adjusted by adjusting the pressure exerted by the springs 104 as described hereinabove. In other respects the embodiment shown in Figs. 7 and 8 operates as that shown in Fig. 1.

It should be understood that numerous changes may be made in the form, construction, and arrangement of the several parts of the illustrated heat exchangers without departing from the spirit and scope of my invention or sacrificing any of its attendant advantages, the heat exchangers herein described being merely for the purpose of illustrating the invention.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is as follows:

1. A heat exchanger for exchanging heat between a solid granular material and a fluid, comprising, in combination, a vertical casing, a plurality of substantially vertical tubes arranged in said casing, a plurality of helical screwshaped members supporting the solid granular material and being arranged, respectively, vertically in said vertical tubes, an upper chamber substantially arranged above said vertical tubes and said screw-shaped members, a distributing device arranged in said upper chamber, said distributing device including at least one automatically revolving part coming into operative connection consecutively with the upper ends of said vertical tubes and supplying the solid granular material successively to said helical screw-shaped members arranged in said vertical tubes and a lower chamber substantially arranged below said vertical tubes and said screw-shaped members, said lower chamber collecting the solid granular material passing through said vertical tubes, an input duct for supplying fluid to the interior of said casing, the fluid entering the upper part of said vertical casing, passing the interior of said vertical casing around said vertical tubes, so as to enter said lower chamber, being distributed therein and passing into said vertical tubes in counterflow to the solid granular material, and an exhaust duct for removing said fluid from said upper chamber, whereby the solid granular material is subjected to an eflective heat exchange with the fluid in said tubes, the fluid exhausts after leaving said vertical tubes via said upper chamber and said exhaust duct.

2. A heat exchanger as claimed in claim 1, and means for imparting movements to said helical screw-shaped members with respect to said tubes.

3. A heat exchanger as claimed in claim 1, said helical screw-shaped members including each a plurality of sections forming a series and being separated from one another by gaps.

4. A heat exchanger as claimed in claim 1, a ringshaped member operatively connected with said revolving part of said distributing device, and driving means for imparting a revolving movement to said ring-shaped member about the axis thereof and to said revolving part of said distributing device operatively connected with said ring-shaped member.

5. A heat exchanger as claimed in claim 4, said ringshaped member having at least one projection imparting revolving movements to said helical screw-shaped members with respect to said tubes.

6. A heat exchanger as claimed in claim 5, said projections being arranged for imparting to said helical screwshaped members reciprocating movements.

7. A heat exchanger as claimed in claim 1, and means arranged in said casing for imparting to the fluid a zigzag flow in said casing before entering said lower chamber.

8. A heat exchanger as claimed in claim 7, and deflecting means arranged in said chamber, said deflecting means deflecting the fluid after flowing in the zigzag flow imparted by said imparting means, into said vertical tubes in counterflow to the solid granular material passing through said vertical tubes.

9. A heat exchanger as claimed in claim 1, said vertical tubes consisting of a ceramic material.

10. A heat exchanger as claimed in claim 1, said helical screw-shaped members being designed as multiple screws.

11. A heat exchanger as defined in claim 4, said driving means being adapted to impart revolving movement at different speeds to said ring-shaped member.

References Cited in the file of this patent UNITED STATES PATENTS 322,257 Chase July 14, 1885 804,876 Noxon Nov. 21, 1905 969,484 Koegler Sept. 6, 1910 1,322,428 Gloess Nov. 18, 1919 1,482,812 Roberts Feb. 5, 1924 1,545,596 Olney July 14, 1925 1,621,651 Bauer Mar. 22, 1927 FOREIGN PATENTS 872,215 France Sept. 21, 1940

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