US3389692A - Flash boiler - Google Patents

Description

June 25, 1968 JOHNSON ET AL 3,389,692

FLASH BOILER 2 Sheets-Sheet 1 DON E. JOHNSON 5L MO .4. PORTQ? mvsw'rons.

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June 25, 1968 D. E. JOHNSON ET AL 3,389,692

FLASH BOILER Filed Dec. 15. 1966 2 Sheets-Sheet 2 oo/v JOHNSON 61440 A. FORTE? INVENTORS.

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United States Patent 3,389,692 FLASH BOILER Don E. Johnson, 524 W. 6th Drive, and Elmo A. Porter, 1025 E. Jarvis Ave., both of Mesa, Ariz. 85201 Filed Dec. 13, 1966, Ser. No. 601,455 11 Claims. (Cl. 122-41) ABSTRACT OF THE DISCLOSURE A flash boiler including a series of concentric tubular members alternately interconnected to provide two flow paths, one path receiving feedwater from the radial outer portion, which is discharged as steam from a central tube, the other path receiving hot gases which pass a chamber where the water is flashed into steam and enter the other flew path around the central tube, each of the paths having a helical baflie therein, the baflles being oppositely wound in the two flow paths.

This invention pertains to a boiler for converting water into superheated steam.

This invention provides an extremely fast acting flash boiler in which the rate of heat transfer is accelerated considerably over that of designs of the prior art. With this boiler, water is converted to steam in an extremely short period of time, even when the boiler is started up from a cold condition. The boiler also is very compact, light and simple to construct.

These results are accomplished through an arrangement of concentric cylinders that define a series of adjacent annular passageways through which the water and the hot burner gases are conducted. The water and heated gases are in alternate layers, circulating in opposite axial directions. Helical baflles are included in the concentric passageways, lengthening the flow paths and providing a swirling effect to increase the heat transfer. The water enters from the outside and is discharged as steam from an axial passageway, while the hot gas enters near the center of the unit and is discharged adjacent its periphery. The water is vaporized at a flash plate positioned at the inlet for the burner gases.

An object of this invention is to provide an improved flash boiler.

Another object of this invention is to provide a flash boiler that will convert water to steam in a very short period of time.

A further object of this invention is to provide a boiler that is compact and light in weight.

An additional object of this invention is to provide a boiler that can be manufactured easily and at a low cost.

Yet another object of this invention is to provide a boiler that can be assembled from desired numbers of modular sections to provide different steam-generating capacities.

These and other objects will become apparent from the following detailed description taken in connection with the accompanying drawing in which:

FIGURE 1 is a longitudinal sectional view of the boiler of this invention;

FIGURE 2 is a transverse sectional view taken along line 2-2 of FIGURE 1;

FIGURE 3 is a transverse sectional view taken along line 33 of FIGURE 1;

FIGURE 4 is an enlarged fragmentary longitudinal sectional view of the concentric cylinders forming a portion of the boiler of the invention; and

FIGURE 5 is a fragmentary perspective view of the members connecting to the separating plate adjacent the gas inlet, removed from the other components of the boiler.

3,389,692 Patented June 25, 1968 ice concentric tubes or cylinders. This includes a centraltubular member 11 at the axis of the unit, spaced outwardly from which is a cylinder 12. An additional cylinder 13 circumscribes and is spaced from the cylinder 12. Beyond the cylinder 13 is the next cylinder 14, followed by the outer cylinder 15. This defines a series of passageways, one of which is provided by the bore of the inner cylindrical member 11 and the others of which are annular in cross section and formed by the spaced concentric cylinders. Thus, there is a passageway 17 between the members 11 and 12, while the latter member and the next cylinder 13 provide an annular passageway 13. Passageway 19 is located between the cylinders 13 and 14, and an outer passageway 20 is formed by the cylinders 14 and 15.

Helical bafiles are provided in the annular passageways, serving both to direct the flow of fluid in the passageways and to hold the cylindrical members in their spaced concentric relationship. The baffles are flat strips of metal wound to a spiral form and closely fitted at the peripheries of the cylindrical members. The innermost baflle 22 is in the passageway 17, while outwardly of it is the baflle 23 in the passageway 18. Baflles 24 and 25 are disposed in the passageways 19 and 20, respectively. The helices in the passageways 17 and 19 are wound in the opposite direction. Similarly, the baffles 23 and 25 in the passageways 18 and 20 provide helices wound in two different directions.

A connection is provided between the passages 17 and 19 through an end member 26 located at the left-hand of the unit as illustrated in FIGURE 1. The connecting member 26 is generally in the shape of half of a toms, providing a smooth bend between the two passageways. The member 26 also closes the end of the passageway 18.

The passageways 18 and 20 also are joined by means of four straight tubes 27 which connect to the passageway 20 adjacent its end wall 28. As best seen in FIGURE 2, the tubes 27 extend through the passageway 19, but are sealed relative to it. They enter the inner passageway 18 in a substantially tangential relationship. An inlet is provided at the opposite end of the passageway 20 by a tube 29 that connects to the cylinder 15.

The periphery of the outer cylinder 15 is wrapped with a high-tensile wire 30. The wire 30 is wound in a continuous length around the circumference of the cylinder 15 with its adjacent turns in contact, thereby providing the outer cylinder and the entire boiler unit with a resistance to bursting forces. This allows the cylinder 20 and the other tubular elements as well to be made of relatively lightweight material, because the wrapped exterior of the outer cylinder provides the unit with adequate strength and renders it perfectly safe. There is an additional wrapping 31 over the wire 30, this being made up of fibers of insulating material. The first portion immediately over the wire 30 is of asbestos fibers, while toward the outer part of the wrapping 31 glass fibers are utilized. The fibers in the wrapping31 also have high tensile strength properties and assist the wire 31} in resisting bursting forces in the boiler. The exterior of the boiler unit is encased in a lightweight metal shell 32.

' The right-hand ends of the cylinders 12 and 13, as the device is shown in FIGURE 1, project outwardly beyond the corresponding ends of the cylinders 14 and 15. An annular plate 34 extends over the ends of the cylinders 12 and 13 to close the passageway 18. The inner edge of the plate 34 is coterminous with the inner periphery of the cylindrical member 12, while the outer edge projects radially beyond the cylinder 13. A tubular element 35 connects to the outer edge of the plate 34, and spaced exteriorly of this is an additional tubular member 37.

3 Opposite theplate 34, the right-hand end of the outer passageway 20 is closed by an annular plate 38 that extends beyond the cylinder to the outer tubular member 37. Consequently, the passageway 19 between the cylinders 13 and 14 connects to a passageway 39 defined by the plates 34 and 38 and the tubular members 35 and 37; A tubular outlet stack 40 connects to the right-hand end of the passageway 39. Extending through the plate 34 adjacent its inner edge are four straight tubes 42. Their diameters are substantially equal to the width of the passageway 18 to which they connect. The tubes 42 enter a housing 43 opposite an end wall 44 that acts as a flash plate when the boiler is in operation. The flash plate is dome-shaped and has a central protuberance 45. The central tube 11 of the boiler extends to the'right beyond the cylinders 12 and 13 through the axis of the Walt 46 of the housing 43 inwardly of the tubes 42. Thus, there is a connection between the passageway 18 and the bore of the tube 11. This is effected by the tubes 42 that extend through the wall 46 into the housing 43 adjacent the outer edges of the dome-shaped wall 44. The curved configuration of the wall 44 of the housing, together with the central protuberance 45, provides a smooth bend in forming the connection to the tube 11.

A wall 48 is provided outwardly of the assembly of the housing 43 and the tubes 11 and 42, curving to the inner edge of the end plate 34. Insulation 49 is provided between the wall 48 and the tubular member 35. The right-hand end of the wall 48 connects to a burner 50 for generating heated gases. These gases, therefore, flow from the burner into the chamber defined by the wall 48. The gases travel past the flash plate 44 and around the four tubes 42 into the inlet of the passageway 17. They are conducted to the left as the device is illustrated through the passageway 17, being given a helical flow pattern by the baffle 22. When the end of the passageway 17 is reached, the member 26 directs the hot gases smoothly back into the passageway 19 so that the axial direction of travel is reversed. Again, the baffle 24 causes the gases to swirl in a helical fashion as the passageway 19 is traversed. Because the bafile 24 is wound oppositely from the baffle 22, the rotational direction of the gas remains the same even though its axial direction has been reversed. At the end of the passageway 19, the gases then flow into the passageway 39 and out through the stack 40. By discharging the gases around the inlet from the burner, the heat losses at this area are minimized because there is a lower temperature differential across the wall around the inlet than would be the case if the wall were exposed to atmosphere.

Water, which normally comes from a condenser, enters the unit from the tube 29, flowing into the passageway 20. The baflle 25 directs the water in a helical flow pattern as it moves leftward in the passageway as the device is shown. When the end of the passageway 20 is reached, the water moves through the four tubes 28 that connect to the passageway 18. At the latter location, the water reverses its travel and moves to the right, again in a helical pattern. The baffles and 23, being oppositely Wound, maintain the same rotational direction of flow for the water despite its reversal in axial direction. At the end of the pasasgeway 18, the water is conducted through the four straight tubes 42 into the housing 43. At this location, the water flows around the inner surface of the baflle plate 44, where it flashed into steam. There is a pressure drop and a temperature rise as the water moves across the hot flash plate 44 and dry steam is produced. The steam then moves axially to the left through the central tube 11 in which it becomes superheated.

The unit is proportioned so that a constant cross-sectional area is provided throughout the flow path of the water, while there is a larger area at the central tube 11 that conducts the steam. There is a much narrower nadial spacing between the cylinders 14 and 15 than that between the cylinders 12 and 13. The greater circumference of the annular space 20, however, results in the same flow capacity as that of the passageway 18. The tube 11 may be around 25% greater in cross-sectional area than that of the water passageways.

With the water and hot gases flowing in alternate annular passageways through the boiler unit, there is maximum opportunity for heat transfer to the water as it travels from the intake to the flash plate. By the time it reaches the flash plate, the water temperature has been elevated and it is nearly to the point of vaporization. The water is flashed into steam at the hottest portion of the unit where the gases coming directly from the burner play on the exterior of the flash plate to cause the vaporization. The unit also provides for heat transfer to the steam to accomplish the superheating as the gases immediately following the contact with the flash plate flow around the steam outlet at the axis of the unit.

This construction provides an exceptionally high rate of heat transfer from the hot gases to the water to effect the conversion of the water into steam. Heat is conducted rapidly through the relatively thin walls of the tubular members 11, 12, 13 and 14 for heating the water throughout its travel through the boiler. The fact that the water and the gases both are traveling in helical flow patterns means that the effective area for heat transfer is large even though the boiler unit is compact in size. The hot gas is made to lose a maximum amount of heat during its flow through the boiler by virtue of the spiral flow and the double pass that the gases make. The helical baffles 22, 23, 24 and 25 not only spacethe tubular members apart but also provide an additional means to transmit heat from the gas passageways to the water passageways.

While described above as a boiler for generating steam, the unit of this invention has general applicability as a heating device. It is particularly well suited to serve as a water heater, in which event there is the same general arrangement of parts, but the burner will not impart suflicient heat to the water to effect vaporization.

Despite the high efiiciency of the unit, it is readily manufactured at a low cost and can be made of lightweight materials. Moreover, it can be made in modules that can be assembled in different numbers to vary the steam-generating capacity. By eliminating the end members 26 and 28 from the unit shown, additional numbers of concentric cylinders may be added to lengthen the boiler. The outermost set of concentric cylinders will be closed by the members 26 and 28. The flow through the unit will be the same as before but the length of travel of the gases and water will be greater, and a larger, amount of water can be converted to steam.

The foregoing detailed description is to be clearly understood as given by way of illustration and example only, the spirit and scope of this invention being limited solely by the appended claims.

We claim:

1. A boiler device comprising means defining a plurality of concentric passageways,

said means including an inner central passageway and successive annular passageways outwardly of said inner central passageway,

means interconnecting alternate one of said passageways so as to define a duality of paths,

baflle means in said annular passageways for providing a helical contour to said passageways,

said baflie means being oppositely wound in adjacent annular passageways,

a first inlet means connected to one of said paths for introducing hot gases therein,

outlet means for said one path for discharging said gases,

a second inlet means connected to the other of said paths for introducing water therein,

and outlet means for said other path for discharging steam therefrom upon heating of said water in said other path by said hot gases. 2. A boiler device comprising a central tubularmember,

a plurality. of tubular members concentric with said -.central tubular member and spaced outwardly therefrom defining a series of annular spaces outwardly of said central tubular member,

means interconnecting alternate ones of said spaces so as to define a duality of paths,

one of said paths being connected to said central tubular member,

a first inlet for said one path at the radial outer portion thereof,

said central tubular member providing an outlet for said one path,

said one path being adapted to receive water at said inlet and to discharge steam at said outlet,

a second inlet for the second of said paths adjacent said central tubular member,

said second inlet being adapted to receive gases,

said second of said paths having a portion connected to said second inlet and circumscribing said central tubular member for conducting such hot gases directly from said second inlet over said central tubular member,

an outlet for said second path at the radial outer portion thereof for discharging said gases, and bafile means in said spaces in said one path and in said second of said paths for cooperating with said tubular members to provide helical passageways through said paths.

3. A device as recited in claim 2 in which for each of said paths the connections between alternate spaces between said tubular members are alternately at opposite ends thereof, whereby flow through said paths reverses axially of said tubular members at said ends.

4. A boiler comprising a plurality of concentric cylinders with the walls thereof in spaced relationship thereby to define annular spaces between said cylinders,

means interconnecting alternate ones of said spaces for providing a duality of flow paths through said cylinders,

helical bafile means in said spaces for directing fluid in said spaces in helical patterns,

said bafile means in one of said flow paths being oppositely wound from the baffie means in the other of said fiow paths,

a housing at one end of said cylinders,

the innermost one of said cylinders connecting to the interior of said housing, the second annular space outwardly from said innermost cylinder being connected to said housing for providing a connection between said inner-most cylinder and said second annular space at said housing, said housing having an end wall, and an inlet passage adapted for receiving heated gases from a burner,

said inlet passage being connected to the annular space immediately outwardly of said innermost cylinder and extending around said housing for thereby conducting said gases around said housing and into said space immediately outwardly of said innermost cylinder.

5. A boiler comprising a first elongated tubular member,

a housing having a hollow interior,

one end of said tubular member extending into said housing,

a second tubular member circumscribing said first hot tubular member and defining a first annularv space between said first and second tubular members,

said second tubular member having an open end inwardly of said end of said first tubular member, athird tubular member circumscribing said second tubular member and defining a second annular space between saidsecond and third tubular members,

said third tubular member having an end inwardly of said end of said first tubular member, means closing said end of said third tubular member, conduit means interconnecting said second space and said housing thereby to interconnect said second space and said first tubular member at said housing, a fourth tubular member circumscribing said third tubular member and defining a third annular space between said third and fourth tubular members, a fifth. tubular member circumscribing said fourth tubular member and defining a fourth annular space between said fourth and fifth tubular members, means interconnecting said fourth space and said second space thereby to provide a first passageway defined by said fourth space, said second space, said conduit means and said first tubular member, water inlet means connected to said fourth space for conducting water through said first passageway, a chamber around said housing,

said chamber extending to said end of said second tubular member and communicating with said first space, means interconnecting said first space and said third space thereby to provide a second passageway defined by said chamber, said first space and said third space,

and inlet means for said chamber for receiving heated gases to be conducted through said second passageway for heating water flowing in said first passageway and converting said water to steam at said housing.

6. A device as recited in claim 5 in which said housing includes an end wall opposed to said end of said first tubular member and said conduit means and in the direct path of gases received from said inlet for said chamber,

said end wall having a dome-shaped contour and including curved surface means for directing said water from said conduit means to said first tubular member.

7. A device as recited in claim 5 including in addition filament means circumscribing said fifth tubular member for providing a resistance to outward forces on said tubular membersj 8. A device as recited in claim 5 including in addition passage means connected to said third space and circumscribing said chamber for conducting said heated gases around said chamber, said passage means having an outlet therefrom for discharging said gases.

9. A device as recited in claim 5 including in addition a helical baffie in each of said spaces for providing a rotational flow pattern in said spaces.

10. A device as recited in claim 9 in which said bafiles in said first and third spaces are oppositely wound,

said bafiles in said second and fourth spaces are oppositely wound,

and said interconnecting means for said first and third spaces and said interconnecting means for said second and fourth spaces are at the ends of said spaces, whereby the direction of rotation of flow is the same in said first and third spaces, and the direction of rotation of flow is the same in said second and fourth spaces. 11. A boiler device comprising a central tubular member,

a plurality of tubular members concentric with said central tubular me'mberandspaced outwardly therefrom defining a series of annular spaces outwardly of said central tubular member, means interconnecting alternate ones of said spaces so as to define a duality of paths,

one of said paths being connected to tubular member, a first inlet for said one path at the radial outer portion thereof,

said central tubular member providing an outlet for said one path,

said one path being adapted to receive water at said inlet and to discharge steam at said outlet, a second inlet for the second of said paths adjacent said central tubular member,

said second inlet being adapted to receive hot gases, an outlet for said second path at the radial outer portion thereof for'discharging said gases, bafile means in said spaces for cooperating with said said central 8 tubular members to provide helical passageways through said paths, and a hollow chamber connected to the annular space of said one path adjacent said central tubular memher for receiving the flow 'in' said one path,"

said hollow chamber including" arcuate: surface means for directing said flow into said'central tubular member, said second inlet communicating with said hollow chamber on the exterior thereof for imparting heat to said hollow chamber and causing water in said one path to flash in-to steam,

References Cited UNITED STATES PATENTS 2,832,320 4/1958 Thome et al. 122-161 XR KENNETH W. SPRAGUE, Primary Examiner.

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