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(11) | EP 0 351 247 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Recovery of heat from flue gases |
| (57) Heat exchange apparatus comprising at least two adjacent rows of tubes (an inner
and an outer row) or at least two spaced rings of helical coils (30) (an inner ring
and an outer ring) for the transfer of heat thereinto from gases passing through the
heat exchange apparatus wherein the tubes of the inner row are, or the inner ring
of coils (30B) is staggered with respect to the tubes of the outer row or coils of
the outer ring (30A) and the inner row or ring (30B) is spaced from the outer (30A)
by such amount to block the flow of gases and prevent streaming of the gases to maximize
turbulence of the gases passing thereby, thereby enhancing heat transfer from the
gases to the tubes or coils (30). In another embodiment the spacing between the adjacent
tubes of the outer row and adjacent coils (30) of the outer ring (30A) was a distance
equal to the distance calculated by multiplying a factor of .500/.875 or about .571
(.5714) by the outside diameter (D) of the coil (30) or tube of the adjacent inner
coil (30b) or tube and which adjacent coils (30) or tubes of the inner row or coil
(30B) is centrally placed in the space between tubes or coils (30) of the outer row
or ring (30A) of helical coils (30) wherein the spacing of the inner row of tubes
or inner ring (30B) is spaced from the outer row or outer ring (30A) by a distance
calculated by multiplying a factor of about 1.250/.875 or 1.429 (1.4286) by the outer
diameter (D) of the inner row of coils (30B) or the inner ring respectively. |
FIELD OF INVENTION
[0001] This invention relates to the recovery of heat from gases and particularly relates to improved apparatus for maximizing the recovery of heat from gases (for example waste or flue gases).
BACKGROUND OF THE INVENTION
[0002] Heat recovery systems are known in which exhaust gases from a source of heat (for example a hot air furnace or boiler) are passed through a heat exchanger in which coil(s) or tube(s) are disposed into which the heat may be transferred. Examples of such systems are shown in U.S. Patent Nos. 4,210,201, 4,136,731, 4,037,567, 4,066,210, and 3,896,992.
[0003] It is known to stagger tubes in adjacent rows of tubes or coils within coils in heat exchange systems. In this regard, European Patent Application No. 84307512.8 (Publication No. 0 149 307) discloses apparatus involving heat transfer which includes a plurality of sets of elements such as cylinders arrayed in rows perpendicular to the direction of flow of the fluid and in which the elements of adjacent rows are staggered with respect to each other. The application teaches that the elements of each row are spatially separated from each other so that open flow space would normally completely surround each element. A partition extends from each element generally parallel to the direction of flow of fluid. Each partition bridges between a pair of elements in alternate rows and is positioned so that it is symmetrically spaced from the adjacent elements of the intervening row. The partitions block by-pass flow of the fluid along diagonal paths between the elements.
[0004] Thus the fluid flow is contained and directed, being funnelled and streamed in an orderly unidirectional flow.
[0005] Reference SU 1285264 discloses a staggered cluster of tubes (2) with longitudinal fins. The even rows in the cluster are offset in the direction of the odd ones towards the motion of the gas. The offset is not more than
, where d is the diameter of the tubes (mm.), S₁ is the transverse pitch of the tube cluster (mm.), and S₂ is the longitudinal pitch of the tube cluster (mm.). The diagonally-directed flows inside the tube cluster are forced towards the lower parts of the tubes and the diagonal velocities are increased, blowing the friable ash deposits from the bottoms of the tubes. The tubes are thus self-cleaning.
[0006] Thus the flow has been redirected to gain velocity and in the oil furnace the tubes are cleaned. Once again the flow has been directed in an orderly fashion (for example unidirectional).
[0007] U.S. Patent No. 4,079,754 relates to apparatus for passing fluid on a controlled basis in either of two opposite directions.
[0008] U.S. Patent No. 3,688,800 discloses a fluid flow restrictor comprising a series of rows of baffles placed in the path of fluid flow with the baffles in succeeding rows staggered with respect to those in adjacent rows so that as the fluid flows it is constrained to change its direction repeatedly.
[0009] U.S. Patent No. 4,456,033 teaches a flow restrictor to minimize noise and cavitation, or other adverse effects, in regulating the flow of a high pressure fluid. The restrictor defines a myriad of tortuous, dissimilar, intertwined, and commingled energy dissipating chambered flow paths edgewise through a stack of sheets of perforated stock material. Adjacent sheets have their perforations out of registration with one another, the inlet and outlet to the restrictor being edgewise through the stack through open-sided ones of the perforations of the several sheets of stock.
[0010] U.S Patent No. 4,019,573 teaches a heat exchanger for exchanging heat between fluids comprising a conduit for flow of a first fluid therethrough comprising a manifold with a single port in one area and a pair of ports in another area and a plurality of spaced fluid tubes attached to the pair of ports with the combination of the plurality of tubes having outer peripheral surfaces describing a cylinder and the inner confronting peripheral surfaces spaced apart to provide an open area therebetween for flow of a second fluid therethrough and means for directing the second fluid over and around both the inner and outer peripheral surfaces and through the open area between the tubes for achieving maximum surface area heat transfer with minimum cross sectional area of conduits.
[0011] U.S. Patent No. 4,512,288 (corresponding to Canadian patent No. 1,235,615) discloses a heat recovery system which recovers heat from flue gases from a furnace or the like and a hot water cylinder. Flue gases are passed through series of chambers in which coils are located. Water is passed through the coils in a direction opposite to flue gas flow to maximize heat transfer and the heated water is passed to either a heat radiating system or into preheater tank for the hot water supply. The coils for the heat radiation and water heating are in separate circuits and the flue gases from the hot water is passed only over the coil used for water heating. Pumps are used for water recirculation in both the heat radiating circuit and the water heating circuit. The system has application to domestic and industrial furnaces which provide gaseous combustion products with recoverable thermal energy and permits the use of a small diameter exhaust vent without adversely affecting the ignition and combustion system of conventional furnaces.
[0012] Applicant is aware that a number of installations by Michaud (the inventor of the above-mentioned U.S. Patent, No. 4,512,288) incorporates at least two vertically oriented coils (one within the other), staggered to some extent with respect to one another with the disposition of the vertical sets of coils being disposed parallel to the flow of hot gases. Reference is made to a brochure entitled "Combustion: Fuel & System Efficiencies", published by the Ministry of Energy (Government of Ontario, Canada), Municipal and Commercial Programs, 56 Wellesley Street West, 10th Floor, Toronto, Ontario, M7A 2B7, which provided under the heading "Big Savings From Waste Heat" that: "Sometimes it is possible to improve the overall energy efficiency of a heating plant without changing the boiler or the fuel supply. The Empire Hotel in Timmins found that its natural gas bills for heating dropped by over 26 per cent in the first 11 months when certain changes were made to the system (see Figure 2).
In December 1985, new water heaters along with new kitchen equipment were installed. At the same time, a heat recuperator was installed on the exhaust from the hot water boiler. This device, a Thermal Energy Saving System or TESS, allows the flue gases to make three passes through a heat exchanger. The unit also condenses the water vapour in the flue products. The heat of the exhaust gas is transferred by the heat exchanger to the domestic hot water system, in effect, preheating it. The Tess unit was developed by the installing contractor, Roger Michaud Services of Timmins.
As a result, the overall efficiency of the heating plant has increased from 60 to 90 per cent. The total cost of the complete renovations to the hotel's energy systems was approximately $30,000. For the first 11 months of 1986, the energy savings totaled $11,073.50. This gives a payback time of approximately 2.5 years.
Jack Laferriere, owner of the Empire Hotel feels the results have been excellent, 'It's cut my heating bill almost in half, and there's been no maintenance required. It took out a loan to finance the cost of the capital equipment. Now I pay the bank instead of the gas company, so my cash flows in unchanged. But once the unit pays for itself, in two to three years, all the savings come back to the Hotel."
[0013] Applicant is also aware of a brochure entitled "T.E.S.S. Thermal Energy Savings System" produced by T.E.S.S. Canada Limited, 8 King Street East, Suite 300, Toronto, Ontario, M5C 1B5, identifying in the brochure places where units have been installed. In the system described: "Hot spent gases from the furnace in excess of 300°F are ducted via a flexible pipe (4) to unit 1. The gases are drawn through the stainless steel duct work (5, 6, 7) by an electric (9) induction fan (8) and exhausted through pipe (10) to atmosphere (11). The original chimney with its high maintenance costs is eliminated. Cold make-up or return water is pumped (12) into the water inlet (13) of unit 3 into the copper coil (14) and progressively through the double coils (14, 15, 16) exiting at hot water outlet (17). Hot water from any separate set of coils provides an infinite temperature range from 130°F to 210°F. This hot water can be utilized for domestic hot water, hanging heaters, preheated boiler water or preheated air for furnace combustion. As the hot gases pass over the coils carrying cooler water; there is condensing effect. The distilled water is collected and drained from each module in the condensate line (18). An exhaust temperature of 140°F will provide only a few drops of water per minute with the balance expelled with the exhaust while an exhaust temperature of 80°F will produce hundreds of gallons of distilled water per day."
[0015] It is therefore an object of the invention to provide improved apparatus which maximize the amount of heat recovered by the apparatus thereby providing apparatus of increased efficiency.
[0016] It is further object of the invention to provide such apparatus of increased efficiency at minimal additional cost.
[0017] Further and other objects of the invention will be realized by those skilled in the art from the following summary of the invention and detailed description of embodiments thereof.
SUMMARY OF THE INVENTION
[0018] In accordance with one aspect of the invention, heat exchange apparatus is provided comprising at least two adjacent (for example horizontally spaced) rows (columns) of tubes (parallel rows of tubes - an inner row and an outer row -) or at least two spaced (for example horizontally concentrically disposed) rings (for example cylindrical columns) of helical coils (for example an inner and an outer ring) for the transfer of heat thereinto from gases wherein the tubes of the inner row are, or the inner ring of coils is staggered with respect to the tubes of the outer row or ring of coils to block the flow of gases and the inner row or ring is spaced from the outer by such amount to prevent streaming of the gases to maximize turbulence of the gases passing thereby, thereby enhancing heat transfer from the gases to the tubes or coils. The source of the hot gases may be a boiler, exhaust gases, flue gases or the like.
[0019] In one embodiment the hot gases may be introduced normal (at right angles) to the orientation of the at least two adjacent spaced rows of the tubes or spaced rings of coils. Thus, the gases engaging the adjacent rows of tubes or rings of coils are blocked and caused to bounce or deflect off the surfaces of the tubes or rings of coils in a random manner to maximize turbulence - to create as much turbulence as possible in three dimensions. The spacing between the tubes or coils in the same row or ring, respectively can be of generally any usable size provided the space between is less than the diameter of the tube or coil in advance (in front) of the row or ring of coils having regard to the direction of flow of the gas towards the tube or coils and the space between adjacent rows or rings of coils does not permit streaming. The diameters of the adjacent rows of tubes and rings of coils may be the same or different.
[0020] The rows of spaced tubes or spaced rings of coils are preferably parallel or concentric as the case may be and the spacing from one another must be such that streaming of the gases passing the tubes or coils must be prevented. For efficient results, where at least two spaced parallel rows of tubes (the tubes in each row being spaced from one another) - an inner row of tubes and an outer row of tubes - or at least two spaced (concentric) rings of helical coils (the coils in each ring being spaced from one another) - an inner ring of helical coils and an outer concentric ring of helical coils - the spacing between the adjacent tubes of the same row or helical coils of the same ring (for example of the outer ring) was a distance equal to the distance calculated by multiplying a factor of about .500/.875 or about .571 (.5714) by the outside diameter of the coils of the adjacent inner ring of coils or the outside diameter of the tubes of the adjacent inner row - the distance between the coils of the same ring or tubes of the same row is calculated with respect to the outside diameter of the coil of the adjacent inner ring or tube of the inner row - and the coil or tube of the inner row or ring is placed directly center of the space.
[0021] Further, the second (inner) row or ring may be spaced from the first (outer) row or outer ring by a distance equal to the distance calculated by multiplying a factor of 1.250/.875 or about 1.429 (1.4286) by the outside diameter of the tubes of the adjacent inner row or the outer diameter of the coils of the adjacent inner ring of coils measuring in the opposite plane (for example horizontal plane). This mathematical relationship holds through the whole structure (whether 2 or 8 or more rings of coils or rows of tubes are used) so that if a third further inner ring of coils is provided, its spacing from the 2nd ring for calculation purposes is as if third ring is the 2nd ring (inner) and the 2nd ring is the first outer ring.
[0022] Preferably the coils or tubes are carried in an enclosed chamber (preferably a turbulence chamber) having an inlet opening for gas to enter the chamber and an outlet for leaving the chamber, the gas in one embodiment being directed to engage the tubes or coils at right angles and in another embodiment be deflected (for example by a deflector, e.g. a conical deflector, situated proximate the entry) for angular engagement of the coils or tubes (in three dimensions) and further deflection.
[0023] The coils or tubes preferably carry liquid and hot gases (e.g. waste or flue) into the chamber. Thus heat may be transferred from the flue gases by the heat exchange coils or tubes to the liquid (for example water) that have been positioned to maximize turbulence for maximizing recovery of heat.
[0024] Baffles or deflectors in one embodiment containing holes and in another embodiment without holes, may be strategically located in the chamber to encourage deflection to reduce streaming of the gases and keep the gas streams splitting and "bouncing". In this regard when the baffles or deflectors are inserted angularly through rows of tubes or coils of the rings which have been spaced in accordance with the factors of .571 and 1.429, the angle of insertion or entry of the baffles or deflectors inserted angularly downwardly through the rows or coils, is in the order of 25o (for example to the horizontal).
[0025] A plate may be provided across the lower portion of the chamber between the tubes and/or coils and the gas outlet with restricted openings provided therethrough. The plate acts as a pressure plate to prevent dead spaces at the corners of the chamber (for example meeting of side wall and bottom). The gases passing through the restricted openings is turbulent and draws any stagnant air from the "dead space". Applicant believes the use of the plate evens out the vacuum across the diameter of the chamber preventing dead air space and gas streaming. With the bouncing and deflection of the gases, the temperature in the chamber at all places in the chamber is the same - homogeneous.
[0026] A number of chambers may be joined and the coils in adjacent chambers may be connected to one another with the flow of fluid (for example water) opposite the flow of the gases from chamber to chamber.
[0027] In a vapour stream created by a positive pressure of atmospheric or blower action coupled with the negative pressure created by an induction fan; a stream of hot flue gas is initiated. In one embodiment the 90° angle change of direction of the flow from one (vertical) plane to another (horizontal) plane creates the initial-turbulence (i.e. the molecules on the outside of an elbow (right angle) must travel faster than the inner molecules of the stream as the stream is pushed from the boiler by the boiler fan and pulled by the induction fan into the molecular turbulence chamber). There are two methods of entry to accomplish this. The molecules are spinning within the stream. Upon contact with the coils two things happen. Firstly the main stream is split several times by the circular surface of the coils. The directional flow of the individual streams is around the surface of the coil exposing the once centre (a) molecules to the thermal conducting (copper) tube. As the stream (b) continues, it is split again into a smaller stream (c) exposing the centre molecules of the (B) stream to the thermal conducting (copper) tube (2) of the inner coil. Simultaneously as this stream breakup occurs upon impact of the copper coils, individual molecules bounce from the coil surface in an infinite number of directions as determined by a molecule or particle impacting a curved coil surface. The molecule upon impact with each coil will transfer its thermal energy to the cooler (copper) surface. Each molecule will strike the coils on several occasions or rebound from the container wall. As the molecules being to fall back into a streaming pattern along the side of the container, the stream is redirected by a directional baffle plate (a metal projection of 90° or greater) for example affixed to the container wall or passing between tubes of adjacent rows or rings of adjacent coils. The stream created by the vacuum will again demonstrated the same action of split streaming and molecular bouncing as the stream impacts the coils. Further thermal energy is then continually given up to the copper coil carrying a colder fluid.
[0028] The application of the invention may be any vapourized element or compound or mixture of elements and compounds requiring a maximum molecular surface exposure to the atoms or molecules of another solid, liquid or vapourized element, or compound or mixture of same, for example:
i) a mixture -
CH₄ methane gas,
SO₂ sulfur dioxide gas,
CO₂ carbon dioxide gas,
N₂ nitrogen gas,
H₂ hydrogen gas,
molecularly exposed or mixed with copper; or
ii) gases - hydrogen gas molecules exposed to oxygen molecules; or
iii) liquids - water molecules exposed to methyl hydrate molecules; or
iv) liquid with solids - water molecules exposed to copper atoms.
[0029] Each and every element, alloy and compound has the capacity to conduct thermal energy to a more or lesser extent. This phenomenon is known as the thermal conductivity of the element, alloy or compound. The ability of the element, alloy or compound to absorb or relinquish this thermal energy is dependent upon two things:
1) the ability of one molecule to transfer its thermal energy to another molecule of the same substance, or
2) the rapid mixing of that substance in order that each molecule is exposed to another molecule.
[0030] For purposes of engineering in any stream of vapour(s) or liquid(s) in a static or dynamic motion is considered as layers of molecules stacked atop each other with molecules holding their relative positions when the fluid or vapour briefly is at rest or in a flow pattern. Consequently when thermal energy (i.e. heat is applied to the surface of the stream), the time for that energy to penetrate to the centre of the stream is dependent on the thermal conductivity of each molecule. The rate of penetration of heat into all molecules of the stream is a result of each molecule being heated and transferring that heat energy to the cooler molecule next to it. Conversely in a hot thermal stream in order to give up its energy molecules in the centre of the stream must transfer that energy from the center of the stream to the cooler surface.
[0031] A faster method of transferring the inner heat to the outer molecules of the stream or vice versa is to expose the inner molecules directly to that surface. Such a method of accomplishing this is by creating turbulence in the stream. The turbulence causes the molecules to rapidly change their relative positions in the stream allowing every molecule to be exposed to the surface of the molecules of the colder atoms or molecules. This turbulence and the subsequent surface exposure of the molecules of the hotter substance to the surface molecules of another substance, transfers the heat energy very quickly through the stream allowing the homogeneous mixture to obtain an equal temperature throughout the stream.
[0032] For maximizing efficiency and reliability a plurality of chambers are provided between which the gases pass (in one direction from one to another, for example under negative pressure) and the gases are spun to add turbulence. In addition the chamber may be covered by insulation and a cover. The tubes or coils may be supported from hangers suspended from the top of the chambers (which top may be separate from the side wall). Each hanger may comprise holes therein to receive the tubes or coil portions and be secured thereto by for example welded bands. The hanger may be bent at one edge along its length and may be cut through the openings to provide two portions. Therefore the coils may be placed in the openings or recesses of the openings in one portion of the hanger and the second or other portion of the hanger secured to the first portion, thereby securing the coils to the hanger (which is suspended from the top). Each set of coils or tubes in the same plane is preferably secured to the top of the chamber by one hanger.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The invention will now be illustrated with respect to the following drawings illustrating embodiments of the invention in which:
Figure 1 is a schematic side view of a series of chambers incorporating embodiments of the invention.
Figure 2 is a partly sectioned view of chambers also incorporating embodiments of the invention.
Figure 3 is a perspective side view of a series of connected chambers constructed according to embodiments of the invention.
Figure 4 is a perspective partly exploded view of some of the assembly shown in Figure 3.
Figure 5 is a perspective partly sectional view of the assembly shown in Figure 4.
Figure 6 is a cross-sectional view through part of the structure shown in Figure 5.
Figure 7 is a top view of the structure shown in Figure 6.
Figures 8, 9 and 10 are views of the method of mounting the coils of the heat exchange system shown in Figure 6.
Figures 11 and 12 are schematic views illustrating the gases passing the coils (and/or tubes) in the heat exchange assembly according to an embodiment of the invention.
Figure 13 is a perspective view of a series of chambers incorporating embodiments of the invention.
Figures 14 through 18 inclusive illustrate the positioning of the tubes or coils relative to one another according to embodiments of the invention.
Figure 19 is a cross-sectional view through one of the chambers shown in Figure 13.
Figures 20 and 21 illustrate perspective views of components used in the chamber of Figure 19.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
[0034] With reference to Figure 1, there is shown a plurality of turbulence chambers 20 each comprising inlets 22 and outlets 24, the outlet of one being the inlet of the chamber next adjacent to it. A source of hot gases (now shown) is drawn through the chambers by negative pressure created by induction fan 26.
[0035] Where the gases enter the top of the chamber, they exit the bottom and vice versa. Pressure plates 28 may be provided across the end of the chamber between the heat exchange rings of helical coils 30 (shown in Figure 2 for example) and/or tubes and the outlet 24. Plate 28 has restricted openings 32 therethrough (see also Figure 2). The plate acts as a pressure plate to prevent dead spaces at the corners of the chamber. In some chambers the gas is introduced at 90° (normal) to the orientation of the chamber to engage the heat exchange coils "head on" as at 34 in Figure 2. In other chambers triangular deflector 36 is provided at the mouth of inlet 22 to deflect the gases to cause turbulence. Baffles 38 (see Figure 2) are provided to keep the gases bouncing and deflecting.
[0036] Within each chamber 20, three rings 30 of helical coils identified as 30A, 30B, and 30C (see Figure 2) are provided for transferring water or other fluid for being heated by the flue gases. To ensure maximum heat transfer, the outer ring 30A is positioned so that the spacing between the vertical spaced helical coils is such that the coils of rings 30B within ring 30A is staggered to fill the openings between the coils of ring 30A and be close enough to ring 30A to ensure no streaming of the gas but rather encourage continuous turbulence. The same is true with coils 30B and 30C (see Figures 11 and 12). The distances between the coils are as has been previously calculated and with this spacing have provided efficient results. Thus, and with reference to Figure 12, where "D" is the outside diameter of the coils of 100 the inner ring 30B, the spacing between the coils 100′ and 100′ of ring 30A is .571D. The spacing between rings 30A and 30B is 1.429D.
[0037] With reference to Figure 2, hot flue gases from a positive pressure source enters chamber 20 and is directed outward by the conical flow diverter 36 into the inner set of spiral coils 30C. The gas stream is split by the coil and while the coil carrying a colder liquid absorbs the thermal energy the stream is further split by coils 30B and still further by 30A. As the molecules in the stream flow around the coils or impact on the coils they transfer their thermal energy to the coil contacted. The molecules bounce in infinite directions as they impact all coils 30A, 30B, and 30C in chamber 20 giving up their thermal energy to the impacted coil. As the stream and molecules are bounced either towards the centre or the outside of the chamber; both bounce back towards the coil from the side of the chamber or the central diverter cylinder 40. The molecules and small streams tend to collect and form larger streams downward along the sides and central diverter cylinder 40. The streams follow these until a directional baffle bar 38 is encountered. The negative pressure created by an induction fan causes the stream to be redirected into the coils 30A, 30B and 30C creating a repeat of the phenomena described previously. The phenomena continues to the bottom of the chamber repeatedly exchanging the molecular thermal energy into the copper coils impacted or contacted.
[0038] Uneven vacuum across the chamber necessitates the balancing of the pressure. This pressure is equalized by the slotted (apertured) pressure plate 28. The flue gas stream is then directed into the next thermal exchange chamber 20 at the injection port 22. The stream impacts the coils therein (in the same way) with repeated thermal loss by the molecules to the coils. Similar to the flue gas action of the first chamber, the flue gas in the next chamber is drawn upward with the flue streaming being deflected into the coils by the direction baffle bars 38 along the sides of the chamber and the central diverter cylinder 40. Again the slotted (apertured) pressure plate 28 evens out the flue gas pressure across the chamber and expels the flue gas out outlet 24 to the next chamber through the injection port 22. The number of interconnected chambers and size of copper coils which create the molecular turbulence determine the thermal energy extraction from the flue gas by the fluid carried in the copper coils in the reverse direction to the flue gas flow.
[0039] By way of example, the following data is offered.
| CONFIGURATION OF HEAT EXCHANGER: | |||
| QUANTITY | UNITS | ||
| Estimated overall heat transfer coefficient (U). | BTU/hr - sq. ft. - deg. F. | 12 | |
| Required surface area of tubes | sq. ft. | 409.55 | |
| Copper tube | |||
| - outside diameter | in. | 1.0000 | |
| - wall thickness | in. | 0.0350 | |
| - internal flow | sq. in. | 0.6793 |
| area | |||
| - inside diameter | in. | 0.9300 | |
| - surface area. | sq. ft./ft. length | 0.2618 | |
| Desired outside diameter of inner (first) coil. | in. | 12.000 | |
| Desired horizontal spacing between tube surfaces. | in. | .571 | X outside diameter (O.D.) of inner tube or inner helical coil |
| Desired vertical spacing between tube surfaces. | in. | 1.429 | X O.D. of inner tube or inner helical coil |
| Total length of tube required. | ft. | 1564.35 |
| NUMBER OF COILS: | 1 | 2 | 3 | 4 | ||
| QUANTITY | UNITS | |||||
| Outside diameter of second ring of helical coils. | in. | NA | 18.000 | 18.000 | 18.000 | 18.000 |
| Outside diameter of third ring of helical coils. | in. | NA | NA | 24 | 24.000 | 24.000 |
| Outside diameter of fourth ring of helical coils. | in. | NA | NA | NA | 30.000 | 30.000 |
| Outside diameter of fifth ring of helical coils. | in. | NA | NA | NA | NA | 36.000 |
| Inside diameter of tank. | in. | 16.000 | 22.000 | 28.000 | 34.000 | 40.000 |
| Number of turns - 1 coil. | 543.22 | 213.41 | 117.16 | 74.69 | 59.96 | |
| Height of unit. | ft. | 90.62 | 35.65 | 19.61 | 12.53 | 8.74 |
| NUMBER OF COILS: | 1 | 2 | 3 | 4 | ||
| QUANTITY | UNITS | |||||
| Required water flow rate through each ring of coils. | ft./hr. | 15764.3 | 7882.2 | 5254.8 | 3941.1 | 3152.9 |
| Means Reynolds number through minimum flow area. | 44744 | 22372 | 14915 | 11186 | 8949 | |
| Friction factor. | 0.02175 | 0.02587 | 0.02863 | 0.03077 | 0.03253 | |
| Head loss due to: | ||||||
| - friction (in each coil) | ft. | 130.7510 | 19.4363 | 6.3733 | 2.8892 | 1.5641 |
| - friction (to/from unit) | ft. | 8.3582 | ||||
| - pipe fittings | ft. | 6.5506 | ||||
| - difference in elevation. | ft. | 10.0000 | ||||
| Total head loss. | ft. | 155.6598 | 44.3451 | 31.2821 | 27.7980 | 26.4729 |
| Horsepower requirement of pump. | HP | 0.5128 | 0.1461 | 0.1031 | 0.0916 | 0.0872 |
| Pump efficiency. | % | 70.00 |
[0040] With reference to Figures 3 to 10 inclusive, chambers 20′ are connected with pipes 50 for carrying liquids connecting coils 30A, 30B and 30C in the chambers 30′. Each of the chambers 30′ is surrounded by insulation 52 (sides, top, etc.) and covered by a cover metal material 54.
[0041] In this embodiment, induction fan 26 draws the flue gases through the chambers as shown by the arrows.
[0042] The helical coils are each secured to the separate tops 30˝ by hanger supports 56 (see Figures 8 and 9) by stainless submerged arc welding for ease of removal of the coils. The top 30˝ is separate from the side wall 31 so the system can be serviced. Metal hanger supports 56 hold the helical coils of the rings 30A, 30B and 30C in place and are silver soldered to the coils. Each hanger support 56 is an elongated piece of metal, one edge being angled at 60 for strengthening purposes (see Figure 10). Each hanger system 56 carries apertures to precisely receive the coils and the elongated hanger is cut for ease of mounting the coils.
[0044] With reference to Figure 13, a plurality of turbulance chambers 120 are shown, each chamber 120 being identical to the others. Each chamber comprises inlet 122 (on top) and outlet 124 (below). Exhaust heat flows from boiler 119 in the direction of the arrows through the chambers 120. Fluid pipes 126 are provided through which fluid to be heated flows in the opposite direction to the direction of flow of the exhaust gases.
[0045] With reference to Figure 19, the internal configuration of each chamber 120 is shown. Three rings 130A, 130B and 130C of helical coils are shown for the transfer of heat thereto from exhaust gases entering inlet 122 of chamber 120 prior to exiting through outlet 124.
[0046] The helical coils of each ring 130A, 130B, and 130C are vertically spaced from one another by a distance "S" = .5714T where "T" is the outer diameter of the helical coils of ring 130B (See Figure 16).
[0047] The rings 130A and 130B are spaced from one another a distance of Y = 1.4286T (See Figure 17). See also Figures 14, 15 and 18.
[0048] For maximizing turbulence deflectors 132 have been provided in vertical alignment below inlet 122. The angles of the sloped side walls 134 to the horizontal are 25o.
[0050] Helical coils of rings 130A, 130B and 130C are positioned for maximum efficiency with respect to one another according to the equations S = .5714T and Y = 1.4286T.
1. Heat exchange apparatus comprising at least two adjacent rows of tubes (an inner
and an outer row) or at least two spaced rings of helical coils (an inner ring and
an outer ring) for the transfer of heat thereinto from gases passing through the heat
exchange apparatus wherein the tubes of the inner row are, or the inner ring of coils
is staggered with respect to the tubes of the outer row or coils of the outer ring
and the inner row or ring is spaced from the outer by such amount to block the flow
of gases and prevent streaming of the gases to maximize turbulence of the gases passing
thereby, thereby enhancing heat transfer from the gases to the tubes or coils.
2. The heat exchange apparatus of Claim 1 wherein hot gases are introduced normal
(at right angles) to the orientation of the at least two adjacent rows of the tubes
or spaced rings of coils thereby causing the gases engaging the adjacent rows of tubes
or rings of coils to be caused to bounce or deflect off the surfaces of the tubes
or coils in a random manner to maximize turbulence.
3. The heat exchange apparatus of Claim 1 or 2 wherein the spacing between the tubes
or coils in the outer row or ring respectively are spaced such that the space therebetween
is less than the diameter of the tube or coil in the inner row or ring respectively
having regard to the direction of flow of the gas towards the outer row or ring.
4. The heat exchange apparatus of Claim 1, 2 or 3 wherein the rows of tubes or rings
of coils are parallel or concentric respectively and the spacing from one another
must be such that streaming of the gases passing the tubes or coils is prevented.
5. The heat exchange apparatus of Claim 1 to 4 inclusive wherein the spacing between
the adjacent tubes of the outer row and adjacent coils of the outer ring was a distance
equal to the distance calculated by multiplying a factor of .500/.875 or about .571
(.5714) by the outside diameter of the coils of the adjacent inner ring of coils or
tubes of the adjacent inner row and which adjacent coils or tubes of the inner row
or ring are centrally placed in the space between tubes or coils of the outer row
or ring of helical coils.
6. The heat exchange apparatus of Claim 5 wherein the spacing of the inner row of
tubes or inner ring is spaced from the outer row or outer ring by a distance calculated
by multiplying a factor of about 1.250/.875 or 1.429 (1.4286) by the outer diameter
of the tubes of the inner row or the outer diameter of the coils of the inner ring
of coils respectively.
7. The heat exchange apparatus of Claim 1 to 4 inclusive wherein the spacing of the
inner row of tubes or inner ring is spaced from the outer row or outer ring by a distance
calculated by multiplying a factor of about 1.250/875 or 1.429 (1.4286) by the outer
diameter of the tubes of the inner row or the outer diameter of the coils of the inner
ring of coils respectively.
8. The heat exchange apparatus of Claim 1, 5, 6 or 7 wherein the coils or tubes are
carried in an enclosed turbulence chamber having an opening for gas to enter the chamber
and an exit for leaving the chamber, the gas being directed to engage the tubes or
coils at right angles or be deflected by at least one deflector carried in the chamber.
9. The heat exchange apparatus of Claim 8 wherein baffles and/or deflectors have been
located in the chamber to encourage deflection to reduce streaming of the gases and
ensure that the gas streams split and "bounce".
10. The heat exchange apparatus of Claim 8 wherein a plate is provided across the
lower portion of the chamber between the tubes and/or coils and the gas exit with
restricted openings provided therethrough to act as a pressure plate to prevent dead
spaces at the corners of the chamber to cause the gases passing through the restricted
openings to draw any stagnant air from any "dead space".
11. The heat exchange apparatus of Claim 8 wherein a number of chambers may be joined
and the tubes or coils in adjacent chambers may be connected to one another with the
flow of fluid opposite the flow of the gases from chamber to chamber.
12. The heat exchange apparatus of Claim 8 wherein the chamber may be covered by insulation
and a cover, the tubes or coils supported from hangers suspended from the top of the
chambers (which top is separate from the side wall).
13. The heat exchange apparatus of Claim 8 wherein the chamber may be covered by insulation
and a cover, the tubes or coils supported from hangers suspended from the top of the
chambers (which top is separate from the side wall) and wherein each hanger may comprise
holes therein to receive the tubes or coils and be secured to the hanger, the hanger
being bent at one edge along its length and in formation cut through the openings
to provide two portions, one portion to receive the coils or tubes placed in the openings
or recesses of the openings in that one portion of the hanger and the second or other
portion of the hanger thereafter secured to the first portion, enclosing the tubes
or coils thereby securing the coils to the hanger.
14. The heat exchange apparatus of Claim 8 wherein the spacing of the inner row of
tubes or inner ring is spaced from the outer row or outer ring a distance calculated
by multiplying a factor of about 1.250/.875 or 1.429 (1.4286) multiplied by the outer
diameter of the inner row of coils of the inner ring respectively, and wherein some
of the baffles or deflectors contain holes.
15. A heat exchange apparatus comprising adjacent rows of tubes or rings helical coils
within a chamber, the tubes or rings of helical coils supported by a hanger, the hanger
comprising holes therein to receive the tubes or coils and be secured to the hanger
proximate the holes, the hanger in formation being cut through the openings to provide
two portions, one portion to receive the coils or tubes placed in the openings of
recesses of the openings in that one portion of the hanger and the second or other
portion of the hanger thereafter secured to the first portion enclosing the tubes
or coils thereby securing the coils to the hanger.
16. Heat exchange apparatus comprising adjacent spaced rows of tubes or spaced rings
of helical coils within a chamber further comprising baffles or deflectors for deflecting
the flow of gases to reduce streaming of the gases and ensure gas streams split or
"bounce", some of which baffles or deflectors pass angularly through rows of the tubes
or coils of the rings.
17. The heat exchange apparatus of Claim 16 wherein the angle of insertion of the
baffles or deflectors is in the order of 25o.
18. The heat exchange apparatus of Claim 5, 6 or 7 wherein baffles or deflectors are
located within the chamber for deflecting the flow of gases to reduce streaming of
the gases and ensure gas streams split or bounce, some of which baffles or deflectors
pass angularly through rows of the tubes or coils of the rings.
19. The heat exchange apparatus of Claim 5, 6 or 7 wherein baffles or deflectors are
located within the chamber for deflecting the flow of gases to reduce streaming of
the gases and ensure gas streams split or bounce, some of which baffles or deflectors
pass angularly through rows of the tubes or coils of the rings at an angle of insertion
in the order of 25o.