HEAT EXCHANGER
A heat exchanger including (a) a fluid conductor including a heat exchange tubing including a first end and a lumen; and (b) a first connecting tubing including an outer surface, a lumen and a first sealing ring disposed about the outer surface of the first connecting tubing, wherein the first connecting tubing is configured for insertion into the lumen of the heat exchange tubing at the first end such that the first sealing ring comes in sealing engagement with the first connecting tubing and the heat exchange tubing while allowing relative movement between the heat exchange tubing and the first connecting tubing and a fluid flow is confined within a lumen formed of the lumen of the first connecting tubing and the lumen of the heat exchange tubing.
This continuation-in-part application claims the benefit of priority from non-provisional application U.S. Ser. No. 15/903,544 filed on Feb. 23, 2018 which in turn claims the benefit of priority from provisional application U.S. Ser. No. 62/463,584 filed Feb. 24, 2017. Each of said applications is incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION 1. The Field of the InventionThe present invention relates to a heat exchanger. More specifically, the present invention is directed to a heat exchanger having a weld-free connection of a heat exchange tubing to its connecting tubings one on each end of the heat exchange tubing.
2. Background ArtIn a tankless fluid heating system, it is critical to have a responsive heat exchanger as the fluid supplied to its end user is not previously heated and stored to anticipate a future demand. In a fluid heater that functions by transferring heat from a heated gas to a fluid flow that is heated before being supplied to its user, the responsiveness of the fluid heater is directly tied to the amount of delay a user experiences between the time a fluid demand is requested to the time the fluid demand is actually delivered to the user. When a new demand arises after a lull in demand, heat is again transferred from a heat source to a fluid flow via a heat exchange tubing in which the fluid flow is contained. As heat obtained via such means must be transferred via conduction via the heat exchange tubing to the fluid flow, it is imperative to select a heat exchange tubing with high thermal conductivity. Various strategies have been devised to increase the responsiveness of a fluid heating system. In cases where the number of heat exchange tubings have been increased to enlarge the surface area for heat transfer, such increase requires that many more tubings be added to supply the same amount of fluid per unit time. Often times, these heat exchange tubings are welded to their connecting tubings by conventional welding techniques, e.g., arc welding, etc., making them susceptible to stress corrosion cracking even when the heat exchange and their corresponding connecting tubings have been made of stainless steel. A heat exchange tubing that is held rigidly in place lacks the ability to thermally expand and contract freely, causing stresses to be built up and relieved repeatedly over time. Eventually each weld joint or another type of rigid joint becomes a leak risk which in turn increases the required maintenance frequency and cost.
There exists a need for a fluid heating system that is long lasting and one which does not require frequent maintenance or one which does not require maintenance of the heat exchange tubing or replacement of the heat exchange tubing/s throughout the useful life of the fluid heating system.
SUMMARY OF THE INVENTIONIn accordance with the present invention, there is provided a heat exchanger including:
(a) a fluid conductor including a heat exchange tubing including a first end and a lumen; and
(b) a first connecting tubing including an outer surface, a lumen and a first sealing ring disposed about the outer surface of the first connecting tubing, wherein the first connecting tubing is configured for insertion into the lumen of the heat exchange tubing at the first end such that the first sealing ring comes in sealing engagement with the first connecting tubing and the heat exchange tubing while allowing relative movement between the heat exchange tubing and the first connecting tubing and a fluid flow is confined within a lumen formed of the lumen of the first connecting tubing and the lumen of the heat exchange tubing.
In one embodiment, the fluid conductor further includes a second end and the heat exchanger further includes a second connecting tubing including an outer surface and a second sealing ring disposed about the outer surface of the second connecting tubing, wherein the second connecting tubing is configured for insertion into the lumen of the heat exchange tubing at the second end such that the second sealing ring comes in sealing engagement with the second connecting tubing and the heat exchange tubing while allowing relative movement between the heat exchange tubing and the second connecting tubing and the fluid flow is confined within said second connecting tubing and the heat exchange tubing.
In accordance with the present invention, there is provided a heat exchanger including:
(a) a fluid conductor including a heat exchange tubing including a lumen, a first end, an outer surface and a first sealing ring disposed about the outer surface at the first end; and
(b) a first connecting tubing including a lumen,
wherein the first end of the heat exchange tubing is configured for insertion into the lumen of the first connecting tubing such that the first sealing ring comes in sealing engagement with the first connecting tubing and the heat exchange tubing while allowing relative movement between the heat exchange tubing and the first connecting tubing and a fluid flow is confined within a lumen formed of the lumen of the first connecting tubing and the lumen of the heat exchange tubing.
In one embodiment, the heat exchange tubing further includes a second end and a second sealing ring disposed about the outer surface at the second end and the heat exchanger further includes a second connecting tubing including a lumen, wherein the second end of the heat exchange tubing is configured for insertion into the lumen of the second connecting tubing such that the second sealing ring comes in sealing engagement with the second connecting tubing and the heat exchange tubing while allowing relative movement between the heat exchange tubing and the second connecting tubing and the fluid flow is confined within the second connecting tubing and the heat exchange tubing.
In one embodiment, the first connecting tubing further includes a central axis and a groove disposed about the central axis on the outer surface of the first connecting tubing, the groove configured for receiving the first sealing ring and retaining the first sealing ring in place to prevent relative motion of the first sealing ring relative to the first connecting tubing. In one embodiment, the heat exchange tubing further includes an outer surface and the heat exchange tubing further includes a plurality of fins each extending from the outer surface of the heat exchange tubing. In one embodiment, each of the plurality of fins includes a thickness and a height and the thickness of at least one of the plurality of fins is about 0.5 mm and the height of the at least one of the plurality of fins is no more than about 10 mm. In one embodiment, the heat exchange tubing further includes a wall thickness of no more than 1.2 mm. In one embodiment, the heat exchange tubing further includes an outer surface and the plurality of fins extend from the heat exchange tubing by attaching the plurality of fins to the outer surface of the heat exchange tubing by laser welding. In one embodiment, the heat exchange tubing and the plurality of fins are constructed from the same material. In one embodiment, the same material is stainless steel.
In accordance with the present invention, there is provided a heat exchanger for heating a fluid flow, the heat exchanger including:
(a) a coil including a top section, a bottom section, a top end, a bottom end and a lumen, the coil configured for receiving the fluid flow at one of the top end and bottom end of the coil and channeling the fluid flow to the other one of the top end and bottom end, wherein the lumen at the top section is configured for receiving a heated gas urged to flow in a direction from the top section of the coil to the bottom section of the coil;
(b) a shroud including a side wall, the side wall including an upper section and a lower section, at least one opening disposed on the upper section of the side wall, wherein the top section of the coil is disposed within the upper section of the shroud and the at least one opening is configured to be aligned with a coil loop of the coil and allows a portion of the heated gas to flow around the coil loop and through the at least one opening to enter a space outside of the shroud, wherein the fluid flow is configured to receive heat from the heated gas flowing around the coil loop; and
(c) at least one aperture disposed at the lower section of the side wall, the at least one aperture configured to allow the portion of the heated gas to reenter the shroud at the lower section of the side wall from the space outside of the shroud to continue heating the bottom section of the coil.
In one embodiment, the at least one opening varies in size from the upper section of the side wall to the lower section of the side wall. In one embodiment, the at least one opening decreases in size from the upper section of the side wall to the lower section of the side wall. In one embodiment, the at least one opening is a slit or a hole or any combination thereof. In one embodiment, the upper section of the shroud is substantially isolated from the lower section of the shroud. In one embodiment, the heated gas is provided by a burner. In one embodiment, the shroud further includes a lumen and at least one drain hole disposed at a bottom edge of the lower section of the shroud and the at least one drain hole is configured for allowing draining of condensate from outside of the shroud to the lumen of the shroud. In one embodiment, the heat exchanger further includes an exhaust pointed in a direction, wherein the at least one opening is configured to decrease in size in the direction.
An object of the present invention is to provide a heat exchanger free from one or more heat exchange tubings that are welded to any connecting tubes.
Another object of the present invention is to provide a heat exchanger free from one or more heat exchange tubings that are welded according to conventional welding practices.
Another object of the present invention is to provide a heat exchanger free from one or more heat exchange tubings that are brazed or soldered.
Another object of the present invention is to provide a heat exchanger that is corrosion resistant.
Another object of the present invention is to provide a heat exchanger having a heat exchange tubing that receives heat flux evenly along its length.
Whereas there may be many embodiments of the present invention, each embodiment may meet one or more of the foregoing recited objects in any combination. It is not intended that each embodiment will necessarily meet each objective. Thus, having broadly outlined the more important features of the present invention in order that the detailed description thereof may be better understood, and that the present contribution to the art may be better appreciated, there are, of course, additional features of the present invention that will be described herein and will form a part of the subject matter of this specification.
In order that the manner in which the above-recited and other advantages and objects of the invention are obtained, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:
- 2—fluid conductor
- 4—fin
- 6—end of fluid conductor
- 8—connecting tubing
- 10—wall thickness of fluid conductor
- 12—thickness of fin
- 14—height of fin
- 16—lumen diameter
- 18—distance between fins
- 20—fluid
- 22—sealing ring
- 24—groove
- 26—union
- 28—fluid flow
- 30—blower
- 32—flue flow
- 34—condensate flow
- 36—exhaust
- 38—burner
- 40—drain hole
- 42—weld seam
- 44—central axis of heat exchange tubing
- 46—central axis of connecting tubing
- 48—lip
- 50—lip
- 52—outer shell
- 54—guide system
- 56—shroud
- 58—opening, e.g., slit
- 60—aperture
- 62—shelf
- 64—edge of shelf
- 66—coil loop
- 68—coil loop
- 70—opening
- 72—opening
- 74—opening
- 76—one end of annular plate with opening
- 78—another end of annular plate with opening
The present heat exchanger is free of fluid conductors joined with conventional welding thereby eliminating the possibility of stress corrosion cracking associated with weld joints formed of conventional welding. Each conventional weld joint is a corrosion and leak risk.
The present heat exchanger is robust against thermal cycles as it allows for expansion and contraction of the heat exchange tubing.
The present heat exchanger includes a low mass heat exchange tubing that allows rapid response to varying flows within the heat exchange tubing.
The present heat exchanger includes a large passage that allows large flows and minimizes pressure drop and calcium carbonate scale deposits.
The present heat exchanger includes a heat exchange tubing that is disposed with a lumen that is disposed upright and a blower that causes a flue flow that urges condensate to drip downwardly and away from the heat exchange tubing, thereby causing the heat exchanger to self-clean during the course of normal operation of the heat exchanger.
In one embodiment, the present heat exchanger includes a heat exchange tubing that is not fixed in its position in either end. Therefore, any thermal expansions and contractions in the tubing are not restricted such that thermal cyclic stresses do not develop in the tubing.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENTThe term “about” is used herein to mean approximately, roughly, around, or in the region of. When the term “about” is used in conjunction with a numerical range, it modifies that range by extending the boundaries above and below the numerical values set forth. In general, the term “about” is used herein to modify a numerical value above and below the stated value by a variance of 20 percent up or down (higher or lower).
As the fluid conductor 2 expands in length and radially as it is heated and contracts in the same directions as it is cooled, a fluid conductor that is not restricted in its length and its radial direction does not develop stresses that would otherwise exist in a fluid conductor that is restricted at least at one of its ends.
A plurality of drain holes 40 (only one drain hole is shown) are disposed about the bottom edge of the shroud 56 to allow condensate that may collect between the outer shell 52 and the shroud 56 to enter the lumen of the shroud 56 and eventually be carried to the exhaust 36 and drained.
In shall be noted that the plurality of slits vary in size from the upper section of the side wall to the lower section of the side wall as slits spiral downwardly from the top of the side wall to the bottom of the side wall. The openings decrease in size from the upper section of the side wall to the lower section of the side wall. By disposing openings of decreasing size from the top end of the coil to the bottom end of the coil to coincide with coil loops, the heated gas flow around coil loops can be balanced in the upper section of the shroud, i.e., the rate of heated gas flow around each coil loop is roughly the same. If the openings had been the same for every coil loop, the heated gas flow would have occurred increasingly more readily through the coil loops closer to the exhaust of the heat exchange tubing 2 due to the lower pressure drop these coil loops would have exerted. The size of the openings 58 is inversely proportional to the pressure drop of the flow through it.
The detailed description refers to the accompanying drawings that show, by way of illustration, specific aspects and embodiments in which the present disclosed embodiments may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice aspects of the present invention. Other embodiments may be utilized, and changes may be made without departing from the scope of the disclosed embodiments. The various embodiments can be combined with one or more other embodiments to form new embodiments. The detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims, with the full scope of equivalents to which they may be entitled. It will be appreciated by those of ordinary skill in the art that any arrangement that is calculated to achieve the same purpose may be substituted for the specific embodiments shown. This application is intended to cover any adaptations or variations of embodiments of the present invention. It is to be understood that the above description is intended to be illustrative, and not restrictive, and that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Combinations of the above embodiments and other embodiments will be apparent to those of skill in the art upon studying the above description. The scope of the present disclosed embodiments includes any other applications in which embodiments of the above structures and fabrication methods are used. The scope of the embodiments should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
Claims
1. A heat exchanger comprising:
- (a) a fluid conductor comprising a heat exchange tubing comprising a first end and a lumen; and
- (b) a first connecting tubing comprising an outer surface, a lumen and a first sealing ring disposed about said outer surface of said first connecting tubing, wherein said first connecting tubing is configured for insertion into said lumen of said heat exchange tubing at said first end such that said first sealing ring comes in sealing engagement with said first connecting tubing and said heat exchange tubing while allowing relative movement between said heat exchange tubing and said first connecting tubing and a fluid flow is confined within a lumen formed of said lumen of said first connecting tubing and said lumen of said heat exchange tubing.
2. The heat exchanger of claim 1, wherein said fluid conductor further comprises a second end and said heat exchanger further comprises a second connecting tubing comprising an outer surface and a second sealing ring disposed about said outer surface of said second connecting tubing, wherein said second connecting tubing is configured for insertion into said lumen of said heat exchange tubing at said second end such that said second sealing ring comes in sealing engagement with said second connecting tubing and said heat exchange tubing while allowing relative movement between said heat exchange tubing and said second connecting tubing and the fluid flow is confined within said second connecting tubing and said heat exchange tubing.
3. The heat exchanger of claim 1, wherein said first connecting tubing further comprises a central axis and a groove disposed about said central axis on said outer surface of said first connecting tubing, said groove configured for receiving and retaining said first sealing ring in place to prevent relative motion of said first sealing ring relative to said first connecting tubing.
4. The heat exchanger of claim 1, wherein said heat exchange tubing further comprises an outer surface and said heat exchange tubing further comprises a plurality of fins each extending from said outer surface of said heat exchange tubing.
5. The heat exchanger of claim 4, wherein each of said plurality of fins comprises a thickness and a height and the thickness of at least one of said plurality of fins is about 0.5 mm and the height of said at least one of said plurality of fins is no more than about 10 mm.
6. The heat exchanger of claim 1, wherein said heat exchange tubing further comprises a wall thickness of no more than about 1.2 mm.
7. The heat exchanger of claim 1, wherein said heat exchange tubing further comprises an outer surface and a plurality of fins extending from said heat exchange tubing by attaching said plurality of fins to said outer surface of said heat exchange tubing by laser welding.
8. The heat exchanger of claim 1, wherein said heat exchange tubing and said plurality of fins are constructed from the same material.
9. The heat exchanger of claim 8, wherein said same material is stainless steel.
10. The heat exchanger of claim 1, wherein said heat exchange tubing is a helical coil.
11. A heat exchanger comprising:
- (a) a fluid conductor comprising a heat exchange tubing comprising a lumen, a first end, an outer surface and a first sealing ring disposed about said outer surface at said first end; and
- (b) a first connecting tubing comprising a lumen,
- wherein said first end of said heat exchange tubing is configured for insertion into said lumen of said first connecting tubing such that said first sealing ring comes in sealing engagement with said first connecting tubing and said heat exchange tubing while allowing relative movement between said heat exchange tubing and said first connecting tubing and a fluid flow is confined within a lumen formed of said lumen of said first connecting tubing and said lumen of said heat exchange tubing.
12. The heat exchanger of claim 11, wherein said heat exchange tubing further comprises a central axis and a groove disposed about said central axis on said outer surface of said heat exchange tubing on said first end, said groove configured for receiving and retaining said first sealing ring in place to prevent relative motion of the first sealing ring relative to said heat exchange tubing.
13. A heat exchanger for heating a fluid flow, said heat exchanger comprising:
- (a) a coil comprising a top section, a bottom section, a top end, a bottom end and a lumen, said coil configured for receiving the fluid flow at one of said top end and bottom end of said coil and channeling the fluid flow to the other one of said top end and bottom end, wherein said lumen at said top section is configured for receiving a heated gas urged to flow in a direction from said top section of said coil to said bottom section of said coil;
- (b) a shroud comprising a side wall, said side wall comprising an upper section and a lower section, at least one opening disposed on said upper section of said side wall, wherein said top section of said coil is disposed within said upper section of said shroud and said at least one opening is configured to be aligned with a coil loop of said coil and allows a portion of the heated gas to flow around said coil loop and through said at least one opening to enter a space outside of said shroud, wherein the fluid flow is configured to receive heat from the portion of the heated gas flowing around said coil loop; and
- (c) at least one aperture disposed at said lower section of said side wall, said at least one aperture configured to allow the portion of the heated gas to reenter said shroud at said lower section of said side wall from the space outside of said shroud to continue heating said bottom section of said coil.
14. The heat exchanger of claim 13, wherein said at least one opening is configured to vary in size from said upper section of said side wall to said lower section of said side wall.
15. The heat exchanger of claim 13, wherein said at least one opening is configured to decrease in size from said upper section of said side wall to said lower section of said side wall.
16. The heat exchanger of claim 13, said at least one opening is selected from the group consisting of a slit and a hole or any combination thereof.
17. The heat exchanger of claim 13, wherein said upper section of said shroud is substantially isolated from said lower section of said shroud.
18. The heat exchanger of claim 13, wherein the heated gas is provided by a burner.
19. The heat exchanger of claim 13, wherein said shroud further comprises a lumen and at least one drain hole disposed at a bottom edge of said lower section of said shroud and said at least one drain hole is configured for allowing draining of condensate from outside of said shroud to said lumen of said shroud.
20. The heat exchanger of claim 13, further comprising an exhaust pointed in a direction, wherein said at least one opening is configured to decrease in size in said direction.
Type: Application
Filed: Dec 7, 2018
Publication Date: Apr 11, 2019
Inventors: Sridhar Deivasigamani (Peoria, IL), Sivaprasad Akasam (Dunlap, IL)
Application Number: 16/213,930