US3241548A - Submerged combustion apparatus embodying a shallow, closed, rectilinear tank and upstanding liquid separation chamber at one end thereof - Google Patents

Description

March 22, 1966 WALTER 5, SEE ETAL 3,241,548

SUBMERGED COMBUSTION APPARATUS EMBODYING A SHALLOW, CLOSED, RECTILINEAR TANK AND UPSTANDING LIQUID SEPARATION CHAMBER AT ONE END THEREOF Filed May 7, 1962 2 Sheets-Sheet l lllllnunnmlgnyum";

NVENTORBI 3 QWALTER 0. SEE

ARTHUR WILLIE/HS ATT'YS March 22, 1966 TE G 555 ETAL 3,241,548

SUBMERGED COMBUSTION APPARATUS EMBODYING A SHALLOW, CLOSED, RECTILINEAR TANK AND UPSTANDING LIQUID SEPARATION CHAMBER AT ONE END THEREOF 2 Sheets-Sheet 2 Filed May 7, 1962 INVENTORSZ WA LTE R G. S E E ARTHUR WILLIAMS BY W,

ATT YS United States Patent Ofiice 3,241,548 Patented Mar. 22, 1966 3,241,548 SUBMERGED COMBUSTION APPARATUS EM- BODYING A SHALLOW, CLOSED, RECTI- LINEAR TANK AND UPSTANDING LIQUID SEPARATION CHAMBER AT ONE END THEREOF Walter G. See, Crown Point, and Arthur Williams, Munster, Ind., assignors, by mesne assignments, to Selas Corporation of America, a corporation of Pennsylvania Filed May 7, 1962, Ser. No. 192,768 3 Claims. (Cl. 126--360) This application is a continuation-in-part of our application Serial No. 21,310, filed April 11, 1960, now abandoned.

This invention relates to submerged combustion apparatus embodying a shallow, rectilinear, closed tank in which heat is supplied to a body of liquid by direct contact with hot combustion gases and also by indirect heat exchange between the liquid and the walls of hollow members conveying the hot combustion gases to a point or points of discharge into the liquid.

One of the primary objects of this invention is to provide highly efficient apparatus for the heating of liquids by submerged combustion.

Another primary object of this invention is to provide submerged combustion apparatus capable of highly efficient heat transfer of the heat of hot combustion gases into the body of liquid.

Another object of the invention is to provide improvements in water heating vessels.

A further object of the invention is to provide improvements in submerged combustion vessels. These, and other objects and advantages of the invention hereafter described or made apparent to those skilled in the art, may be attained by utilizing the principles of the invention described hereafter with respect to specific embodiments of the invention illustrated in the accompanying drawings wherein:

FIG. 1 is a side elevation of a water or other liquid heating apparatus with a portion thereof broken away to facilitate the illustration of the embodiment;

FIG. 2 is a top plan view of the embodiment of FIG. 1 with a portion thereof broken away to facilitate the illustration of the embodiment;

FIG- 3 is a sectional view taken on section 3-3 of FIG. 2;

FIG. 4 and FIG. 5 are side and rear elevations, respectively, of combustion gas distributing means used in the embodiment of FIGS. 1 and 2;

FIG. 6 is a cross-sectional view taken on section 6--6 of FIG. 5; and

FIG. 7 is a fragmentary view of the side elevation of a modified form of the apparatus of FIGS. 1 and 2.

In FIGS. 1 through 6 there is shown apparatus which is especially adapted for the heating of water or other liquid by means of direct contact between hot gases of combustion and the liquid. This apparatus comprises a tank 1, which is relatively shallow in relation to its length and width. The rectilinear tank 1 is made of an end Wall 2 having in its upper corner an outlet pipe 3 for the heated water or other liquid. The top of the tank 1 is closed by a top wall 4 extending thereacross. The top wall 4 is shorter than the bottom wall 5. The remaining walls of the tank 1 are the side walls 6 and 7. These walls form a water-tight, liquid-holding tank with a riser section or tower section 8 at the end of the tank 1 remote from the outlet pipe 3. The riser section or tower section 8 is of a width coextensive with the width of the tank 1 and is made up of an end wall 9, which also is the end wall for the tank 1, together with end wall 10 and side walls 11 and 12. The top of the rectilinear riser section or tower section 8 is closed by a cover plate 13 through which extends a vapor outlet pipe 14 having a flange 15 for use in connection of the outlet pipe 14 to vapor and gas-conveying piping (not shown).

The end wall 10 has a manhole tube 16 thereon. This manhole tube is closed by removable cover plate 17. The purpose of the manhole tube is to allow operating or maintenance personnel to enter the tank 1 for purposes of cleaning, repair or the like.

There is mounted in the top wall 4 a burner unit 18 of the submerged combustion variety. The burner shown in FIGS. 1 and 2 is a dual combustion burner which will be described in detail hereinafter. The burner plate 19 of the burner unit 18 discharges a fuel gas and air or oxygen gas into the combustion chamber 20. The hot combustion gases are discharged through an opening 21 in the end wall of the combustion chamber 20 into a cylindrical leg 22 of the burner unit. Thereafter, the hot gases flow from the cylindrical leg 22 into a gas outlet tube 23 extending across the lower portion of tank 1. This gas outlet tube 23 is positioned near the end of the tank 1 remote from the tower section 8. The gas outlet tube 23 is supported on the bottom wall 5 of the tank 1 by support plates 24 attached to the bottom wall 5.

The gas outlet tube 23 is illustrated in detail in FIGS. 5 and 6. It comprises an outer tube 25 rotatably supported about an inner tube 26. The tubes 25 and 26, respectively, have gas outlet ports 27, 28 in their lower sides. These ports can be brought into any desired degree of alignment by rotation of the tube 25 about tube 26 by means of pressure against the post 29 fixedly mounted on the tube 25. This adjustable positioning of the ports 27, 28 permits the adjustment of the effective area of the gas outlet ports for a purpose later described.

Water or other liquid to be heated is admitted to the heating unit through the inlet pipe 30 located in the upper portion of the side wall 12 of the tower section 8. Heated water, on the other hand, is discharged through the outlet pipe 3 located in the corner of the end wall 2. The corner of the tank 1 from which the heated water is discharged is divided from the rest of the tank by a diagonal corner plate 31. The corner plate 31 contains near its lower end a series of ports 32 which communicate the triangular corner compartment and the main body of the tank 1. The corner compartment has a temperature sensing probe 33 therein, which probe is connected by cable 34 to an automatic temperature controller 35. The temperature controller 35, in turn, controls the quantity of fuel gas and air or oxygen gas supplied to the burner so that a substantially level temperature is maintained in the heated liquid discharged from the heating apparatus.

The water supply unit in the tower 8 comprises a coupling 36 attached to the inlet pipe 30. A series of three branch, distributing pipes 37, 38, 39 are mounted in the coupling 36. Each of these branch pipes has a right elbow 40 at its outer end with short vertical pipes 41 depending downwardly from the elbows 40. Water admitted to the heating vessel is discharged from the three pipes 41, which are located near the gas and vapor outlet pipe 14. The water falls through the warm gases rising in the tower section 8. If desired, the outlet pipes 41 may be provided with coarse spray nozzles to increase the contact between the water and the rising gases so that there is a greater transfer of the residual heat in the rising gases to the descending Water. Fine sprays are ordinarily to be avoided because of the tendency of the entrainment of mist in the gases emitted through the outlet pipe 14.

Fuel gas is supplied to the burner through the fuel gas main supply pipe 42, which has a shut-off valve 43 and a gas pressure regulator 44. The main supply pipe 42 is branched into an inner burner gas supply pipe and an outer burner gas supply pipe 46, each of which is connected to a distributing head in the gas burner. The details of the gas burner will be described hereinafter.

Each of the gas supply pipes 45 and 46 have manually operable shut-off valves 48 by which gas flow can be shut off to either or both of the inner burner distributor head 49 or outer burner distributor head 50. The inner burner gas supply pipe 45 has a small branch pipe 52 by which gas is supplied to the pilot tube distributing head 51 of the combustion burner.

For economical reasons, it is usually preferable to use air as the combustion supporting gas. Accordingly, the heating vessel of the invention has an air blower-compressor 53 mounted on the top wall 4 of the tank 1. The blower-compressor is driven by an electric motor 54. The air is discharged from the blower-compressor 53 through the main air supply pipe 55 to the distributing head of the outer burner. A portion of the air in pipe 55 flows through branch pipe 56 to the distributing head of the inner burner and a small portion of the air flowing through branch pipe 56 flows through branch pipe 57 to the distributing head of the pilot burner.

One of the important features of the apparatus of this invention is in the burner turn down control system by which the amount of gas supplied to the outer burner and the amount of air supplied to the outer burner is accomplished at predetermined, variable ratios. This aspect of the invention is provided by a butterfly valve 58 in the main air supply pipe 55 and a butterfly valve 59 in the main gas supply pipe 46, both of which pipes are connected to the distributor head for the outer burner. The butterfly plates of each of the butterfly valves are rotated by link arms 60 and 61 for the valves 58 and 59', respectively. Link arms 60 and 61 are connected by a connecting link arm 62 pivotally connected to the ends of each of the arms 60 and 61. These interlinked arms are, in turn, connected by a pivot link 63 to a rotatable arm 64 of a reversible motor 65. The motor 65 is controlled by known means by the temperature regulator 35. The electrical connection between the temperature controller 35 and the reversible motor 65 is shown symbolically by the arrows on these members in FIG. 1.

It will be noted from FIG. 2 that the link arm 60 for the butterfly valve 58 in the main air supply pipe 55 is longer than the link arm 61 to the butterfly valve 59 in the main gas supply pipe 46. The purpose of these link arms of greater length is to provide a different degree of rotation of the butterfly plates in the valves 58 and 59 when the arm 64 is rotated by the motor 65. It has ben found that the outer burner cannot be turned down from its maximum gas and air flow by equally proportionate decreases of the air and gas flow through the outer burner without encountering a rough or banging operation. For example, it has been found in the operation of the dual combustion burner that when the fuel gas flow is turned down to a fiow of 40% of the maximum flow of gas through the outer burner, the air flow cannot be decreased to 40% of the maximum air flow without encountering a rough or banging operation. In order to have a smooth outer burner operation, the air must be decreased in the order of only about of the maximum air flow of the outer burner when the gas flow is turned down to a value of 40% of the maximum gas flow, in order to maintain sulficient velocity at the orifices of the burner plate to prevent the encountering of the rough or hanging operations.

Therefore, the link arm 60 is proportionately longer than the link arm 61 so that a given amount of movement of the link arm 63 by the motor arm 64 causes the butterfiy plate of the valve 58 to rotate a lesser degree of angular rotation than the rotation of the butterfly plate of the valve 59. Thus, the turn down or turn up of the outer burner by adjustment of the butterfly valves via the mechanical linkage is done under conditions wherein there is a lesser amount of turn down in the air supply than in the gas supply during burner turn down and a greater amount of turn up in the outer burner gas supply than in the outer burner air supply during burner turn up.

The foregoing burner turn up and turn down mechanism is especially useful in burners which operate under discharge of gases into the body of liquid through orifices having a constant size opening, e.g., the tube 26 Without the rotatable outer tube 25 thereon. Where, however, means is provided to partly close the gas discharge holes or orifices when the burner is turned down and to open the holes or orifices when the burner is turned up in direct proportion to the change in combustion gas supply resulting from the turn down or turn up,

i.e., the tube structure illustrated in FIGS. 5 and 6, the" outer burner can be turned down or turnedup under conditions of equally proportionate changes" in the airgas supply rate. With a burner operating under automatic temperature control, it is usually more feasible to use a structure having the mechanical linkage illustrated in FIGS. 1 and 2 for turning down or turning up the outer burner along with a gas discharge tube 26 having constant size orifice openings.

The gas supply pipes 45 and 46 have a pressure regulator 66 therein for maintaining the desired gas pressure. The control panel 67 is mounted on the tank 1. It contains the control buttons for activating and deactivating motor 54, pressure gauges, and other instrumentation and controls for operating the combustion burner.

Thus, it will be seen that the apparatus of FIGS. 1 through 6 is especially suitable for the heating of water to a predetermined temperature by direct heat exchange between hot combustion gases and the water, or other liquid, if desired. The burner control system is one in which the quantity of combustion gas output can be controlled automatically in relation to the temperature of the water or other liquid being heated. The function of the tower section 8 is one of containing substantially any entrained water rising with the hot combustion gases out of the liquid being heated. The height to which the entrained drops rise in a given heating apparatus under maximum combustion gas output can be determined under operating conditions. It is considered the best practice to make the height of the tower 8 18 to 24 inches greater than the highest rise of entrained liquid. The release of hot combustion gases is done in the portion of the tank under the plate 4 so that these gases will rise in the part of the tank 1 under the plate 4. They then pass along the bottom of the plate 4 into the tower section 8. Under these conditions, excellent utilization of the total heat of the combustion gases is attained, i.e., a transfer of about or more of the usable heat from the gases to the liquid being heated.

The burner 18 shown in FIGS. 1 and 2, with its dual burner structure, is shown in our US. Patent No. 3,192,- 920, issued July 6, 1965.

The inner and outer burners are concentric, independently operable burner units having a large range capacity of B.t.u. output. The inner burner has a lesser B.t.u. output capacity than the larger, outer burner. With this type of concentric burner relationship, the smaller inner burner can be ignited relatively smoothly by the ignited gases of the pilot tube. The inner burner, once ignited, can then serve as the pilot burner for ignition of the higher B.t.u. capacity outer burner which is in surrounding relationship therewith. Each burner can be turned down, turned up or shut down independently of the other burner to give a readily variable range of B.t.u. output of the burner as a whole. The orifices for the air passages of the inner and outer burners are preferably large ports, while the orifices for the fuel gas passages in the burner plate are preferably relatively small orifices spaced closely together.

Various types of burner plates may be employed to provide varying amounts of air and combustible gas to be burned by the burner. For example, the size and/or number of the openings in the burner plates may be varied to provide the desired amount of gas supplied at the burner plate. Also, the size of the ports may be varied to conform the amount of combustion-supporting gas, such as air, with the amount of gas being supplied to thereby provide maximum etficiency of the burner. It is, thus, possible to vary the B.t.u. output of the main burner or the pilot burner by merely changing the burner plate.

By way of illustration, the pilot burner may be one having a capacity of approximately 5 10 B.t.u. and the outer or main burner may have a maximum output of about x10 B.t.u. The outer'or main burner may be used to add from 1 10 to 10 l0 B.t.u. to the 5x10 B.t.u. pilot burner. Thus, in one unit there is a maximum capacity of x 10 B.t.u. and a minimum capacity of 5x10 B.t.u. Further, it is possible to cut the pilot burner back to a lesser B.t.u. output value, as for example, 2.5 X10 B.t.u.giving a range in the capacity of heat supplied from this single burner from about 2.5)(10 to 15 10 B.t.u. By providing an additional burner in surrounding relationship with the main burner it is possible to achieve even much larger values in maximum B.t.u. output while still retaining the desirable features of smooth ignition and operation of the burner as a whole.

The foregoing values of B.t.u. output are not to be construed as anything but illustrative of the invention herein described. The pilot burner may have a smaller or greater maximum B.t.u. output, and the outer or main burner may also have a smaller or larger B.t.u. output than the values given above by way of illustration. In the preferred practice of the invention, however, the maximum B.t.u. output of the outer burner will be substantially greater than the maximum B.t.u. output of the inwardly adjacent burner.

The embodiment of FIG. 7 is one especially adapted for use in the evaporation or condensation of a liquid by vaporization thereof. Since temperature control is not a significant factor in most evaporation processes, the temperature control mechanism and automatically responsive mechanical linkage for turning down or turning up the outer burner air and fuel gas flow can be omitted in most evaporating vessels. structurally, the evaporating vessel of FIG. 7 is very similar to the heating vessel of FIGS. 1 and 2 with the temperature control regulator 35 and the butterfly valves 58, 59 and their associated parts omitted. In this embodiment, the burners are turned down and turned up by the manual control valves. Because the main structural change in the embodiment of FIG. 7 with respect to the embodiment of FIGS. 1 and 2 lies in the liquid supply and discharge arrangement for the tank 1, only the lower portion of the tank has been illustrated. The remaining portions are similar to the parts illustrated in FIGS. 1 and 2 and, hence, need not be repeated.

In the evaporating vessel of FIG. 7, the liquid, such as water containing dissolved salts or the like, is admitted to the tank 1 through the inlet pipe 84 connected by an union 85 to a manual valve 86. The solution is heated by gases discharged from the tube 23 beneath the level of the liquid. The concentrated solution is withdrawn through the outlet pipe 87, to which it is connected by an union 88 to the manual valve 89. The submerged combustion burner 18 may be a dual combustion burner or it may be a combustion burner having only a single burner.

The evaporating vessel of the embodiment of FIG. 7 ordinarily will not need temperature control instruments for regulating the heat output of the submerged burner inasmuch as the primary objective of these embodiments is to provide an apparatus for concentrating the liquid with highly efficient heat exchange between the hot gases and the liquid. Where, however, the liquid is being concentrated is susceptible to decomposition or the like, a liquid temperature control of the type shown for the embodiment of FIGS. 1 and 2 may be employed. Hence, the gas flow control to the combustion burners for these embodiments of the invention may be either a manual type control or an automatic type control. An automatic type control for the dual combustion burner of our aforesaid US. patent is shown therein.

The various illustrated embodiments of the invention have a number of structural similarities. In each case, the liquid is heated by indirect heat exchange through the walls of the combustion chamber and combustion gasconveying means located below the surface of the liquid in the vessel and by direct heat exchange with the hot combustion gases discharged into the liquid from a plurality of small orifices in a submerged tube or tubes. The gases and vapors are discharged from a vapor and gas chamber extending above the liquid-holding tank a sufiicient distance to preclude substantial entrainment of liquid particles (to be contrasted with vapors from the liquid). The combustion gases are discharged into the liquid below a top plate so that, when the vessels are operated with the liquid level below the level of the said plate, the structures of the illustrated embodiments have the advantage of improved removal of entrained liquid particles from the gases and vapors because they must travel under the plate before they reach the vapor and gas chamber. By such structure, the release space in which the entrained liquid is released from the gases is extended over a substantial length, i.e., the space in which they flow through the liquid-holding tank plus the space in the vapor and gas chamber. These spaces must be sufiiciently large to provide a low enough gas velocity to allow the entrained liquid to be released from the gases.

A submerged combustion apparatus of the type characterized above has been disclosed previously in our copending application Serial No. 21,310, filed April 11,

1960, the disclosure of which is herein incorporated by 2 reference as if it had been set forth in its entirety. The apparatus of this copending application is a liquid heating apparatus in which the tank and the liquid-separation tower are similar in structure to the apparatus of FIGS. 1 and 2 herein. The hot combustion gases are conducted from a submerged combustion burner via a hollow arm or arms and discharged below the surface of a liquid in the tank, the point of discharge being below the top, cover plate of the tank. Liquid is introduced into the tower as in FIGS. 1 and 2 herein.

The tower in our aforesaid copending application may be a tower containing packing through which the liquid introduced into the tower gravitates. This aids in the removal of entrained liquid in the combustion gases discharged through the tower and also provides a better surface contact between the incoming liquid and the vapors carried with the combustion gases so that these vapors will condense and be returned to the body of liquid along with the liquid gravitating through the packed tower. In liquid heating apparatus, as contrasted with evaporating apparatus, the tower packing has the advantage of minimizing liquid loss through vaporization. vaporization is not a desired characteristic in a liquid heating apparatus, whereas in evaporating apparatus, vaporization is desired.

In the embodiments herein disclosed which are used as liquid heating apparatus, i.e., FIGS. 1 and 2, the towers 8 and 118 may contain, if desired, packing such as Raschig rings, spiral rings, stoneware, Berl saddles, and the like for the purposes above described.

Other features of the invention such as the dual burner and its fuel gas and air flow control devices, the liquidtemperature-responsive system for adjusting the heat output of the burner in response to the liquid temperature, and others heretofore described usually are employed to best advantage in certain types of liquid heating applications.

The illustrated embodiments are those which we now consider to be the best modes for practice of the generic principles and concepts of the invention. The invention includes within its spirit and scope, as defined in the appended claims, still other embodiments thereof.

The invention is hereby claimed as follows:

1. Submerged combustion apparatus comprising an extended, horizontal, closed, rectilinear tank having a length which is much greater than its depth and adapted to hold a liquid to be heated therein, the top wall of said tank constituting a substantially horizontal plate having a length which is also much greater than said depth and covering all but one end of said rectilinear tank, wall means on said tank located at said one end of said tank defining a closed, rectilinear, upstanding liquid-separation chamber extending across said end of said tank the full Width of said end, projecting upwardly from said tank and communicating with the upper portion of said tank, means for venting combustion gases and vapor from said liquid-separation chamber, a combustion burner mounted on said tank with the combustion chamber extending into the bottom portion of said tank, hollow arm means extending outwardly from said combustion chamber substantially adjacent the opposite end of said tank along the bottom thereof, and a plurality of gas discharge orifices in said hollow arm means through which hot combustion gases are adapted to be discharged beneath the surface of a liquid in said tank, whereby the upper portion of said tank constitutes an extension of said liquidseparation chamber and forms therewith an extended path for the release of entrained liquid in the gases and vapors before said gases and vapors are discharged through said means for venting the gases and vapors.

2. The apparatus of claim 1 wherein the hollow arm means has means for varying the effective sizes of said orifices.

3. The apparatus of claim 1 including means adapted to admit liquid to said tank and to discharge heated liquid from said tank, said liquid discharge means located at a corner of said tank, said corner located at said opposite end of said tank and divided from the rest of the tank by a diagonal corner plate having a series of ports therein.

References Cited by the Examiner UNITED STATES PATENTS 1,511,246 10/1924 Van Daam 158-99 1,689,551 10/1928 Hammond 158-99 1,940,355 12/1933 Knapp 236-20 2,358,302 9/1944 Brosius 126-360 2,432,942 12/1947 See et al. 126-360 X 2,536,608 1/1951 Kemp 126-360 2,797,746 7/1957 Bourek et al. 158-119 2,823,740 2/1958 Morck 158-119 2,902,029 9/1959 Iill 126-360 3,080,302 3/1963 Rogers et al. 126-360 X FREDERICK L. MATTESON, JR., Primary Examiner.

JOHN J. CAMBY, JAMES W. .WESTHAVER,

Examiners.

Claims (1)

1. SUBMERGED COMBUSTION APPARATUS COMPRISING AN EXTENDED, HORIZONTAL, CLOSED, RECTILINEAR TANK HAVING A LENGTH WHICH IS MUCH GREATER THAN ITS DEPTH AND ADAPTED TO HOLD A LIQUID TO BE HEATED THEREIN, THE TOP WALL OF SAID TANK CONSTITUTING A SUBSTANTIALLY HORIZONTAL PLATE HAVING A LENGTH WHICH IS ALSO MUCH GREATER THAN SAID DEPTH AND COVERING ALL BUT ONE END OF SAID RECTILINEAR TANK, WALL MEANS ON SAID TANK LOCATED AT SAID ONE END OF SAID TANK DEFINING A CLOSED, RECTILINEAR, UPSTANDING LIQUID-SEPARATION CHAMBER EXTENDING ACROSS SAID END OF SAID TANK THE FULL WIDTH OF SAID END, PROJECTING UPWARDLY FROM SAID TANK AND COMMUNICATING WITH THE UPPER PORTION OF SAID TANK, MEANS FOR VENTING COMBUSTION GASES AND VAPOR FROM SAID LIQUID-SEPARATION CHAMBER, A COMBUSTION BURNER MOUNTED ON SAID TANK WITH THE COMBUSTION CHAMBER EXTENDING INTO THE BOTTOM PORTION OF SAID TANK, HOLLOW ARM MEANS EXTENDING OUTWARDLY FROM SAID COMBUSTION CHAMBER SUBSTANTIALLY ADJACENT THE OPPOSITE END OF SAID TANK ALONG THE BOTTOM THEREOF, AND A PLURALITY OF GAS DISCHARGE ORIFICES IN SAID HOLLOW ARM MEANS THROUGH WHICH HOT COMBUSTION GASES ARE ADAPTED TO BE DISCHARGED BENEATH THE SURFACE OF A LIQUID IN SAID TANK, WHEREBY THE UPPER PORTION OF SAID TANK CONSTITUTES AN EXTENSION OF SAID LIQUIDSEPARATION CHAMBER AND FORMS THEREWITH AN EXTENDED PATH FOR THE RELEASE OF ENTRAINED LIQUID IN THE GASES AND VAPORS BEFORE SAID GASES AND VAPORS ARE DISCHARGED THROUGH SAID MEANS FOR VENTING THE GASES AND VAPORS.

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