US2289494A - Vaporizer - Google Patents

Description

July 14, 1942. F. v. HADLEY ErAL VAPORIZER Filed April 16. 1940 Af/ All S T. aVu M mm 3 mm. nvc IKV .mO .w n m FU .W

Patented July 14, 1942 VAPORIZER Frederick V. Hadley, Boston, and John 0. Clarke, Jamaica Plain, Mass.

Application April 16, 1940, Serial No. 329,900

Claims.

This invention relates to improvements in vaporizing apparatus of the type in which liquid under pressure is delivered into the path of a gaseous fluid under pressure by means of which the liquid is atomized or vaporized and mixed with the gaseous fluid under pressure.

The object of the invention is broadly to provide mechanism which will more thoroughly atomize the liquid and intermingle it with the gaseous fluid under pressure to produce a homogeneous mixture which will be discharged in a wholly invisible form or in the form of a fog.

More particularly the invention relates to improvements in oil burning apparatus employing steam for vaporizing the oil and is designed to overcome the inherent faults in such burners due to the high velocity of the steam ordinarily employed which results in hardness of flame, and the high percentage of steam required for atomization which causes improper atomization and the production of sparks (oil particles burning in suspension) which causes rapid deterioration of the boiler walls.

The present invention is designed to deliver the gaseous fluid mixture into the combustion chamber of the furnace at a low velocity which will produce a full clear flame having no sparks and which is such that at high boiler ratings there will be no cutting or spalling action upon the refractory linings of the boilers and no danger of injury to the tubes or crown sheets of the boiler.

One of the principal objects of the invention is to provide an oil burner of this character comprising a distributor for the gaseous fluid under pressure and liquid so constructed that a change in pressure of the gaseous fluid will automatically vary the rate of flow of liquid into the jets of gaseous fluid, while the liquid is maintained at constant pressure, in inverse proportion to the change in pressure of the gaseous fluid, that is, to say that increase in the pressure of the gaseous fluid will cause the delivery of liquid into the jets of gaseous fluid at a reduced rate proportionately to the increase in pressure of the gaseous fluid and vice versa.

The present invention also comprises a construction in which increased pressure of the liquid, while the gaseous fluid is maintained at a constant pressure, will increase the delivery of liquid to the jets of gaseous fluid under pressure in a direct proportion to the increase in the pressure of the liquid.

In liquid vaporizing apparatus of the type described the jets of liquid-bearing gaseous fluid usually projects the fuel mixture into a mixing chamber or a succession of mixing chambers having baiiles -.to reverse the direction of movement of the liquid-carrying gas more thoroughly to disintegrate the globules of liquid and to cause an eddying of the liquid-carrying gas which will facilitate vaporization or atomization of the liquid.

The present invention comprises certain improvements operable in conjunction with the jetproducing means to produce a far more homogeneous vaporization or atomization. When the invention is embodied in oil burning apparatus this resulting homogeneous mixture of oil and steam when supplied at relatively low pressures produces a soft flame containing substantially no sparks so that a maximum heating efflciency is attained and injury to the furnace or boilers in which the burner is employed is effectively avoided.

The particular embodiment of the invention illustrated herein comprises certain improvements upon the prior patent granted to Frederick V. Hadley, Stanley Barnaby and John 0. Clarke, No. 1,462,504, July 24, 1923.

In that construction a cylindrical conduit for gaseous fluid under pressure, which concentrically surrounds a conduit for liquid, is connected to the inlet end of a casing having a plurality of mixing chambers provided with suitable baflies, and a cylindrical distributor which is connected to the end of the liquid conduit is provided with passages for delivering the liquid into the path of jets of gaseous fluid under pressure which are produced by longitudinal grooves in the periphery of the distributor' The cylindrical distributoris of slightly less diameter than the internal diameter of the conduit for the gaseous fluid under pressure thereby leaving a cylindrical annular passage around the distributor through which a portion of the gaseous fluid under pressure passes, thus providing a substantially cylindrical or co-noidal envelope which encloses the liquid-carrying jets which merge from the longitudinal channels of the distributor.

The present invention diflers therefrom in that means are provided for causing all of the gaseous fluid under pressure to pass through a plurality, preferably a circular series of ports having converging inlet sections communicating with devfirging outlet sections which produce a Venturi-like construction,

A further object of the invention is to provide the distributor with means for increasing the efficiency of vaporization of the liquid. This is accomplished by providing recesses, preferably in the diverging outlets of the Venturi-like jetproducing passages, which are believed to cause an eddying of the liquid and gaseous fluid within the outlet sections of the distributor and which effect a more thorough distribution of the liquid in the liquid-carrying jets which are discharged from the distributor.

The distributor is provided with a central conduit having passages leading therefrom to the ports for the fluid under pressure, the ports and passages being so proportioned, constructed and arranged that a change in pressure of the gaseous fluid or a change in the pressure of the liquid will automatically vary the rate of delivery of liquid to the atomizing jets in the manner above described.

A further object of the invention is to provide novel forms of mixing chambers and bailies through which the liquid-carrying gas is forced which will eifect a more thorough atomization of the liquid and the delivery of a more homogeneous vaporized or atomized mixture than in usual types of vaporizing apparatus heretofore constructed.

These and other objects and features of the invention will more fully appear from the following description and the accompanying drawing and will be particularly pointed out in the claims.

A preferred embodiment of the invention as applied to oil burners is illustrated in the accompanying drawing, in which,

Fig. 1 is a vertical central longitudinal section of the vaporizing apparatus and a conventional oil-burning head, the pipe leading from the vaporizing apparatus to the head being broken away; and,

Fig. 2 is an enlarged end view of the distributor viewed from the left toward the right.

The particular embodiment of the invention disclosed herein is, as above stated, an improvement upon the vaporizing apparatus for oil burners disclosed in the prior Patent No. 1,462,504 above identified and the means for supplying liquid and gaseous fluid under pressure, such as oil under pressure, and steam under pressure may be and preferably is similar to that disclosed in the aforesaid patent and need not therefore be described herein.

The specific form of oil burner illustrated comprises a preferably cylindrical metal casing I, which may be of bronze or other suitable material, having a primary mixing chamber 2 of general cylindrical form provided with a cylindrical inlet 3 with concavedly curved Walls 4 leading therefrom to the cylindrical portion 2. The chamber is also provided with curved converging walls 5 which lead to a suitable outlet 6 for delivering liquid into a secondary chamber 1 desirably also of substantially the same form as the primary mixing chamber 2. A baffle 8, which preferably is located intermediate of the length of the primary mixing chamber, presents a spherically concave surface 9 against which the liquid-carrying gases are projected by the jets issuing from a distributor hereinafter to be described The liquid-carrying gas is thus reversed in its direction of flow and caused to eddy within the anterior portion of the mixing chamber and passes therefrom through suitable apertures l0 into the posterior part of the chamber where it is contracted by the converging walls of the posterior chamber and caused to pass with higher velocity through the outlet 6 into the anterior portion of the secondary mixing chamber 1. The secondary mixing chamber likewise desirably has intermediate of its length a baflle II having a conical portion I2 in axial alinement with the outlet 6. The wall of the cone I2 is reversely curved at its base to provide the annular channel [3 which acts further to reverse the direction of flow of the liquid-carrying gas and to permit it again to expand in the secondary chamber. The periphery of the annular channel presents a sharp edge M which will cut and disintegrate any particles of unmixed oil which impinge against it. The liquid-carrying gas passes from the anterior portion of the secondary mixing chamber through peripheral passages l5 into the anterior chamber. The converging walls of the chamber again increase the velocity of the liquid as it is delivered into a pipe I6 leading to the burner head I l.

The jet-producing distributor desirably is in the form of a cylindrical block l8 of steel or other suitable metal which tightly fits the cylindrical inlet in the casing leading to the mixing chambers. If the distributor and the casing are: of different materials only sufficient tolerance is: provided to permit relative expansion and contraction due to the different coefficients of ex pansion of said materials. If, however, this distributor and casing are of the same material nosuch clearance is necessary as one feature of the invention is to provide means which will compel all of the gaseous fluid under pressure to pass through the jet-producing portion of the distributor.

Where the distributor and casing are of materials having different coefficient of expansion means are employed to prevent any leakage of the gaseous fluid under pressure through the space between the distributor and the casing. In the particular construction illustrated a union is provided for connecting the conduit for the fluid under pressure to the casing having means positively to close any space intermediate of the distributor and the casing. As illustrated herein the union comprises a sleeve I!) which is of smaller internal diameter than the diameter of the distributor and presents a surfaced end 20 which abuts against the complementary surfaced end of the distributor. Desirably the sleeve 19 is provided with a beveled end portion 2| which engages a complementary beveled surface at the end of the casing. The sleeve has adjacent such beveled surface an annular flange or rib 22 which is engaged by a complementary flange 23 upon a nut 24 which engages complementary screw threads upon the reduced end 25 of the casing.

The sleeve l 9 is provided with internal threads which engage complementary threads upon the end of the inlet pipe 25 through which fluid under pressure is supplied, The distributor I 8 has an integral tubular stem 26 which is coupled by a suitable union 2! with a conduit 28 through which oil is supplied to the distributor.

The distributor is provided with a circular series of circular ports having converging inlet sections 29 which communicate with complementary diverging outlet sections 30 forming a Venturi-like construction adapted to increase the velocity of flow of the liquid as it is formed into jets.

The liquid is delivered from the conduit 28 through an axially alined conduit 3| in the stem 26 of the distributor and therefrom through preferably-radial passages 32 tothe respective throats of the Venturi-like distributor ports. The passages 32 preferably communicate with the outlet sections 30 of the ports adjacent the narrowest portions thereof which are the throats of the Venturi-like construction.

In order more effectively to mix the liquid with the rapidly flowing gas as it passes through the ports of the distributor recesses 33 are provided in the diverging tapering walls of the outlet sections of the ports to communicatewith the passages 32. These recesses desirably are formed by drilling partially cylindrical holes in the walls of the outlet sections of the ports into communication with the passages .32, the walls of the cylindrical bores desirably being contiguous to the outer periphery of the tapering walls of the outlet'sections of the ports,.as illustrated in Fig. 2. Desirably the cylindrical'holes are substantially of the same diameter as the diameter .of the throat of the Venturi-like ports and are parallel to the axis of the distributor.

The distributor desirably is provided with a central boss34 in axial .alinement with the conductor 3| and a screw. threaded plug detachably mounted in. said boss is adapted to be removed to permit cleaning of the conduit.

In the operation of the device suitable gaseous fluid under pressure, such as steam, is supplied from .a suitable source at substantial superatmospheric pressure; such as from a steam boiler which is heated by the burner, through a suitable reducingvalve at a desirably low pressure. The liquid, such as .oil, is likewise supplied under substantial super-atmospheric pressure, preferably the same pressure as that of the gaseous fluid, suitable regulation being made of the oil pressure in accordance with its viscosity or other condition. If desired the il may be heated in the .manner disclosed in prior Patent No. 1,462,504 in such manner as to obtain the best results. ;As the gaseous fluid under pressure flows through the ports of the distributor, oil which -is forced through the passage 32 by the oil pressure, is agitated in the recesses 33 and mixed with the gaseous fluid and the mixture is projected forcibly against the concave surfaced of the baffle 8. The direction oi flow of each jet of the liquid-carrying fluid is thereby reflected toward the axis of said spherically concave abutment and across the path of other .jets and caused to eddy and expand in the anterior portion of the mixing chamber 2. Itpasses therefrom through the apertures J into the posterior portion of the mixing chamber in which it is contracted and caused to flow at an increased velocity through the inlet 6 into the secondary mixing chamber. The constricted column of liquid-bearing gas is then projected upon the conical surface of the baffle II which serves by impingement thereupon to disintegrate globules of liquid which may be present in the mixture and the direction of flow is again reversed by the annular concave channel I3 at the base of the cone and any globules which strike the sharp peripheral edge M of the wall of the channel I3 are further split and disintegrated. The liquidcarrying gas is again permitted to expand in the anterior portion of the secondary mixing chamber and to eddy therein and finally to pass out of the posterior section of said chamber Where it is again contracted by the converging wall and caused to flow at an increased velocity through the pipe [6 leading to the burner. The gaseous mixture which passes from the preferably flat outlet slit 35 of the burner is in the form of such homogeneous I, mixture, free from sparking oil particles that it c'ombinesreadily with the oxygen of the air to produce a soft flame which will deliver a maximum amount of heat to the furnace which will have no cutting or spalling action upon the linings of the boiler and which willnot injure the tubes or crown sheets of the boiler.

Byv reason, therefore, of'the present construction an oil burner of maximum efliciency is provided. It is found in actual practice that variation in steam pressure in the boiler from which steam is supplied to the conduit leading to the burner will vary therate of flow of oil into the ports of, the distributor inxinverse proportion to the variation in boiler pressure. In fact it is found that upon suflicient increase in the pressure of the steam supplied to the distributor,

while the oil pressure remains constant, substantially no oil will be delivered through the passages leading from the oil conduit to the jets of steam issuing from the ports of the distributor.

Conversely it is .found in actual practice that by increasing the oil pressure, while :a proper amount of steam pressure is maintained constant, the amount of oil delivered to the jets issuing from the distributor will increase in direct proportion to the increase in pressure .of the oil.

It will be understood that the particular, embodiment of the invention disclosed herein is "of an illustrative character and is not restrictive,

and that various changes in form, construction and arrangement of parts may be made within the spirit and scope of the following claims.

Having thus describedthe invention, what is claimed as new, and desired to be secured .by Letters Patent is:

1. A liquid vaporizer comprising a casing having a mixing chamber of general cylindrical form and a cylindrical inlet of less diameter concentric therewith, a conduit for a gaseous fluid under substantial super-atmospheric pressure communicating with said inlet, a conduit for liquid under substantialsuper-atmospheric pressure coaxial with said inlet provided with a distributor having a cylindrical head tightly fitting said cylindrical inlet and having a concentric series of circular Venturi-like port s spaced from the periphery of said head for delivering a series of jets of gaseous fluid under increased velocity longitudinally of said chamber, said head having radial passages for delivering the liquid from the liquid conduit to the respective throats of the Venturi-like ports and longitudinally extending cylindrical recesses in the diverging walls of said ports communicating with said radial liquid passages acting in conjunction with the outlet sections of said Venturi-like ports to cause such eddying of the liquid and gaseous fluid in said outlet sections as to vary the rate of delivery of the liquid while maintained under constant pressure to said jets in inverse proportion to changes in pressure of the gaseous fluid, and conversely upon change in pressure of the liquid while the pressure of the gaseous fluid remains constant to vary the rate of delivery of the liquid to said jets in direct proportion to changes in liquid pressure.

2. An oil burner comprising a casing provided with a mixing chamber of general cylindrical form and a cylindrical inlet of less diameter, a conduit for an oxidizing gaseous fluid under pressure communicating with said inlet, a conduit for oil under pressure of relatively small diameter coaxial with said inlet having a cylindrical distributor head tightly fitting said cylindrical inlet and having a concentric series of Venturi-like ports spaced from the periphery of said head for delivering a series of jets of said gaseous fluid under pressure in axial parallelism to the axis of said head, means for delivering oil from said oil conduit to the throats of the respective Venturi-like ports, and a transverseabutment in said mixing chamber spaced from said head having a spherically concave surface in axial alinement with that of said distributor head whereby each of the jets of liquid bearing gaseous fluid will impinge against the spherically concave surface of said abutment at a distance from its axis and be initially reflected toward the axis of the concave face of the abutment and intersect the paths of other similarly reflected jets.

3. An oil burner comprising a casing provided with a mixing chamber of general cylindrical form having an inlet of less diameter and a converging outlet, a conduit for an oxidizing gaseous fluid under pressure communicating with said inlet, a conduit for oil under pressure of relatively small diameter coaxial with said inlet having a cylindrical distributor head tightly fitting said cylindrical inlet and having a concentric series of circular Venturi-like ports spaced from the periphery of said head for delivering a series of jets of gaseous fluid under pressure in axial parallelism to the axis of said head, radial passages in said head for delivering liquid from the liquid conduit to the respective throats of the Venturi-like ports, and longitudinally extending cylindrical recesses of substantially the same diameter as the liquid delivery passages in the diverging walls of the respective ports communicating with said liquid passages, acting in conjunction with the outlet sections of said Venturilike ports to cause such eddying of the liquid and gaseous fuel in said outlet sections as to vary the rate of delivery of the liquid while maintained under constant pressure to said jets in inverse proportion to changes in pressure of the gaseous fluid, and a transverse abutment in said mixing chamber spaced from said head having a spherically concave face in axial parallelism with said distributor head whereby each of the jets of liquid bearing gaseous fluid will impinge against the spherically concave surface of said abutment at a distance from its axis and be initially reflected toward the axis of the concave face of the abutment and intersect the paths of other similarly reflected jets.

4. An oil burner comprising a casing provided with a mixing chamber of general cylindrical form having a cylindrical inlet of less diameter and a relatively restricted outlet in axial alinement therewith, an abutment intermediate of the length of said chamber having a, spherically concave face and a plurality of peripheral ports, a secondary chamber of substantially cylindrical form communicating with the outlet of said primary chamber and having a restricted outlet, a conical abutment intermediate of the length of said chamber having its apex in axial alinement with the outlet of said primary chamber and located in proximity thereto and having an annular groove at its base of semi-cylindrical form, and peripheral passages leading therefrom to the outlet of said secondary chamber, a conduit for an oxidizing gaseous fluid under pressure communicating with said inlet, a conduit for oil under pressure of relatively small diameter coaxial with said inlet having a cylindrical distributor head tightly fitting said cylindrical inlet and having a concentric series of Venturi-like ports concentric with but spaced from the periphery of said head for projecting a series of jets of gaseous fluid under pressure against the spherical concave face of the abutment in said primary mixing chamber, radial passages in said head for delivering liquid from the liquid conduit to the respective throats of the Venturilike ports, whereby globules of liquid carried by said jets will be projected upon the concave face of said abutment, broken up and caused thoroughly to intermingle with said oxidizing gaseous fluid and any globules remaining in said mixture and deliver from said primary mixing chamber, impinge upon the conical abutment of said secondary mixing chamber, and thereupon be more thoroughly vaporized by said gaseous fluid in the secondary mixing chamber.

5. An oil burner comprising a casing provided with a mixing chamber of general cylindrical form having an inlet of less diameter and a converging outlet and an abutment intermediate of the length of said mixing chamber-presenting a spherically concave face in axial alinement with said inlet, a conduit for oil under pressure of smaller diameter than said inlet having a distributing head tightly fitting said inlet provided with a concentric series of circular Venturi-like ports spaced from the periphery of said head, a conduit for an oxidizing gaseous fluid under pressure concentrically surrounding the oil inlet conduit, a union connecting said gaseous fluid conduit to the inlet end of said casing having a smaller internal diameter than said inlet and tightly abutting against the inlet end of said casing and also against said distributing head acting to prevent the passage of any gaseous fluid under pressure between said head and the wall of said inlet thereby insuring the passage of all of said gaseous fluid under pressure through said Venturi-like ports, and means for conducting oil from said oil conduit to the throats of the respective Venturi-like ports.

FREDERICK V. HADLEY. JOHN O. CLARKE.

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