US2556822A - Carburetor for high-pressure valves - Google Patents

Description

June 12, 1951 J. B. ROGERS 2,556,822

7 CARBURETOR FOR HIGH-PRESSURE VALVES Filed May 10, 1948 zit/1T I Patented June 12, 1951 UNITED CARBURETOB; FOR HIGH-PRES SURE VALVES J ohnBerrien Rogers,.Pasadena, Md. Applicatitjn' May 10, 1948; Sl'iaIND. 26,173

12-Claims.

This invention is a novelcarburetor for hi pressure valves usedin connection withapparatus for feeding granular or finely divided solid material from a feed hopper at atmospheric pressure into a mixing chamber having a: pressure above atmospheric, in acontinuous operation, the present invention being an improvement upon that disclosed in my U. S Letters Patent No. 2,.- 428,995, issued October 14, 1947; also upon my joint application Serial No. 772,034,.filedseptember 4, 1947,-now abandoned. While the. invention is susceptible to many applications, the same is particularly adapted for feeding pulverized coal for thorough mixture with a stream of high pressure air passing throughsaidcarburetor.

The principal object of the present invention is to provide novel means of mixing air: and a finely divided or pulverized coalzin'as nearly per-- fectly constant proportions as possible; The pulverized coal is introduced into carburetor by means of the feed throat valve arrangedto bring the coal into the carburetor in an almost perfectly even fiow, it being the function of the carburetor tomix this even-flow of coal into an even flow of air in as: nearly perfectly constant proportions-aspossi-ble; To do this, the coal-must be first removed from its po'int of entry; i. e, the perimeter of the: valve: seat, immediatelyand completely; and secondly, the coalm'ust be thoro'ughly mixed into the air immediately after its removal from the valveseat.

A further object of the invention is tdprovide a carburetor of the above type inwhich the air is initially brought tangentially into 'a distribution chamber disposedat the inner portion oi the carburetor to impart to the air a rotary motion aroundthe feed throat which distributes theair evenly with respect to an annular series of. louvres separating the distribution chamber and a mixing chamberdisposed at the outer portion of the carburetor. These louvresare pitched at an'acute angle to the flow of the air and their combined area is such that with the proper volume and pressure therotation of the: air isin'creasedagreatly and its velocity is stepped up to a point where it will remove the solid material from the feed throat valve in a positive manner. These .louvres are disposed insuch a manner that the whirling high velocity air in the mixing chamber is directed onto and completely around the perimeter of the feed throat valve seat which accomplishes the first of my objectives. The: second objective is attained by simply allowing. the solid material and high velocity air to whirl around within the mixing chamber. From the distribution side of the louvres' 0n'-and as far as desired to convey it pneumatically,v the velocity of the air is never allowed to fall below 5000 feet per minutethis velocity in the mixing chamber creating an intense turbulence which thoroughly mixes the solid materialwith the air.

Thus it can be seen that I accomplish the first of my objectives by supplying. air at a great enough velocity to insure the removal (of the solidmaterial) as fast as it is fed through the feed valve and with enough pressure to make the operation perfectly positive. The second objective is accomplished by the greatturbulenc'e createdby the high velocitiesused.

I will explain the invention with reference to the accompanying drawing, which illustrates one practical embodiment thereof to enable others familiar with the art to adopt'and use the same; and will summarize in the claims the novel features of construction and novel combinations of parts, for which protection is desired.

In said drawing:

Figure 1 is a longitudinal-section through the carburetor,. showing the feed throat, valve, and adjacent partsof thehopper.

Fig; 2 is an end elevation taken on the line 2--2',.Fig. 1, showing. the lo-uvres for-med between the distribution chamber and mixing chamber to impart whirling motion to the primary air as it enters the mixing. chamber.

Fig. 3 is a section, partly in elevation, on the line 3-'3, Fig. 2'.

The feed hopper i is provided with a bottom la and an opening lb in its'end communicating with the inlet of a cylindrical feed throat casing 2 having an inner wall 2a adapted to be secured, by bolts 3 or the like, to the end of hopper i.

Extending axially through the feed throat 2 is a shaft 4 having a reduced end journaled in the far end wall of an annular mixing chamber 5, hereinafter described, said end wall having a bore 511 receiving the reduced end of the shaft 4' and having an antifriction bearing 6 housed in an enlarged bore 51) of the end wall. The'outer end of bore 512 is covered by a cap or plate T (Fig. 1), and a suitable packing 8 is interposed between shaft 4 and an intermediate bore 50 in the end wall which packing 8 is compressed by a ring 9 threaded into the tapped outer end of the intermediatebor'e 50; as shown.

Around the feed throat 2 is an annular chamher A for primary air distribution, the chamber A being formed between the exterior of the feed throat: 2 and the inner wall 211 of the feed throat casing-andan annular outer wall Zb'and an outer end wall 20, the primary air, under pressure, being introduced thereinto through a pipe i which enters the lower portion of chamber A at an angle to or substantially tangent to chamber A, thus causing the air within said chamber to have a rapid swirling motion around th feed throat 2.

In the end wall 2c of chamber A are a series of louvres 211 preferably, but not necessarily, formed integrally therewith, the louvres 2d discharging into an annular mixing chamber B formed between the end wall 2c of the feed throat casing and the annular mixing chamber casing 5, as shown, whereby the air discharged through the louvres at an acute angle to the rotary motion of air in chamber A, will likewise have a swirling motion, the air emerging from a tangentially arranged outlet M. in the top of the mixing chamber B. As shown, the mixing chamber casing has an inwardly extending hub portion 56 for the bearing for shaft 3, said hub potrion imparting an annular shape to the mixing chamber B, and the hub portion terminating adjacent the outer face of the end wall 2c of the air distribution chamber A.

The outer end of the bore of the feed throat 2 is internally beveled as at 2e (Fig. l) and a disclike valve it, of rubber or other yieldabie material, is keyed on shaft 4 and has a beveled outer ed e l2f corresponding with the beveled portion 2c of the feed throat, as shown in Fig. 1, a roundedged collar i3 around shaft i being interposed between the inner end of the hub 56 of easing i": and the outer face of valve 12. The shaft 5 carries a conveyor night 42) whose periphery makes a close contact with the bore of feed throat 2, the flight terminating adjacent the inner face of valve !2, but extending into the hopper.

The flight lb during rotation of shaft i draws the finely divided coal or other material from hopper l and passes it outwardly of the feed throat 2, past the valve [2 and into the mixing chamber B. The resiliency of the material of valve 42, whether it be rubber, plastic or metal, will cause the beveled periphery 22 of the valve to normally seat against the beveled portion 2a of the feed throat, but as the pulverized material is forced out of the feed throat the resiliency of valve l2 will cause same to accommodate itself to any fluctuations in the flow of the finely divided or granular solid material. Thus in any case whether the feed hopper is empty or material is flowing, the valve l2 forms a seal which will prevent the high pressure in the mixing chamber B from escaping backwardly through the feed throat 2 into hopper i, from whence the same could pass directly into the atmosphere.

A secondary function of valve i2 is to cause the finely divided coal or other material to flow more evenly to the mixing chamber B, said valve being fixedly mounted on the shaft 4 and rotating with the material being fed by the Lia, thus reducing wear on the valve 52. In event the how of material stops, the valve 12 will assume its normal sealing or closed position against the valve seat 26 and prevent loss of pressure from the mixing chamber B back through the feed throat.

The above construction provides novel means of mixing air and a finely divided solid material such as pulverized coal in as nearly perfectly constant proportions as possible. The solid material is introduced into the carburetor mixing chamber B by means of the feed throat valve 52 which valve will bring the solids into the carburetor mixing chamber B in an almost perfectly even flow, it being the prime function of the carburetor to mix this even flow of solid material into an even now of air in as nearly perfectly constant proportions as possible. To do this the solid material must first be removed from its point of entry, i. e., the periphery 2c of the valve seat, immediately and completely; and secondly the coal must be thoroughly mixed into the air at once.

Air is brought tangentially into distribution chamber A by inlet 10 in such manner that the air has imparted thereto a rotary or swirling motion around the feed throat 2 thereby distributing the air evenly to the series of louvres 26. disposed between the distribution chamber A and the mixing chamber B. These louvres are pitched at an acute angle to the how of the air and their combined area is such that, with the proper volume and pressure, the rotation of the air is increased greatly and the velocity is stepped up to a point where it will remove the solid material from the feed throat valve in a positive manner. The louvres 2d are disposed in such a manner that the whirling high velocity air is directed on and completely around the perimeter of the feed throat valve seat 22, which accomplishes the first of my objectives. The second objective is attained by simply allowing the solid material and high velocity air to whirl around in the mixing chamber B. From the distribution side of the louvres, as far as desired to convey the mixture pneumatically, the velocity of the air is never allowed to fall below 5000 feet per minute, the velocity in the mixing chamber B creating an intense turbulence which thoroughly mixes the solid material with the air.

Thus it can be seen that I accomplish the first of my objectives by supplying air at a great enough velocity to insure that the removal of the solid material is as fast as it is fed and with enough pressure to make the operation perfectly positive. The second objective is accomplished by the great turbulence created by the high vclocities which I used. The flexible feed throat valve l2 eliminates any back pressure and causes the pulverized coal to enter the mixing chamber B in a perfectly even flow. The primary air is brought into the mixing chamber B through the louvres 201 which are disposed at a very acute angle to the flow of the air imparting a rotary motion to the air entering the mixing chamber. The areas of the louvres 2d and throughout the mixing chamber B are such that in combination with the pressure of the primary air a velocity of more than 5000 feet per minute is maintained at all times. The primary air is brought into the carburetor at 0, tangentially, which causes it to flow around the feed throat 2 and through the distribution chamber A in a swirling manner which distributes it evenly to the louvres 2d, the air rotating in the desired direction. The primary air and coal mixture leave the carburetor through pipe M which is disposed tangentially on the far side of the mixing chamber B.

I claim:

1. In combination with a hopper for finely divided solid material, a carburetor for mixing said material at atmospheric pressure with air above atmospheric pressure, comprising a feed throat extending from the hopper; a shaft extending through said throat; a conveyor flight on the shaft terminating adjacent the discharge end of said throat, the periphery thereof slidably en-. gaging the walls of said bore; a wall enveloping the feed throat and forming therewith an annue;

5 lar air distribution chamber closed at both ends; an annular casing contiguous to the outer end of the distribution chamber beyond the throat and forming an annular mixing chamber; a resilient valve within the mixing chamber and normally closing the outer end of the throat; the outer end of the distribution chamber having an annular series of louvres therein inclined in the same direction and discharging into the mixing chamber; a tangentially disposed inlet for air under pressure into the distribution chamber; and a tangentially disposed outlet from the mixing chamber.

2. In combination as set forth in claim 1, said louvres being disposed at an acute angle to the swirling movement of the air in the distribution chamber, and being of such combined area that the air volume and pressure of the swirling air chamber will immediately remove the material as it is discharged past the said valve, the air and material swirling within the mixing chamber before passing through the said outlet.

3. In a combination as set forth in claim 1, the combined area of louvres being such that the minimum air velocity within the mixing chamber will be substantially 5000 feet per minute, thereby setting up an intense turbulence therein to thoroughly mix the solid material with the air.

4. In combination with a hopper for finely divided solid material, a carburetor for mixing said material at atmospheric pressure with air above atmospheric pressure, comprising a cylindrical feed throat having a bore communicating with the hopper; a shaft extending through said bore; a conveyor flight on the shaft terminating adjacent the discharge end of said bore, the periphery of said flight slidably engaging the walls of said bore; the outer end of said bore being internally beveled to form a valve seat; an annular wall around and spaced from the feed throat and forming an annular air distribution chamber closed at both ends; an annular casing contiguous to the outer end of the distribution chamber beyond the throat and forming an annular mixing chamber; a resilient valve mounted on and rotating with the shaft within the mixing chamber and having a beveled periphery normally seating upon and closing the valve seat; the outer end of the distribution chamber having an annular series of louvres therein inclined in the same direction and discharging into the mixing chamber; a tangentially disposed inlet into the distribution chamber for air under pressure; and a tangentially disposed outlet from the mixing chamber.

5. In a combination as set forth in claim 4, said louvres being disposed at an acute angle to the swirling movement of the air in the distribution chamber, and being of such combined area that the air volume and pressure of the swirlin air will immediately remove the material as it is discharged past the said valve, the air and material swirling within the mixing chamber before passing through the said outlet.

6. In a combination as set forth in claim 4, the combined area of louvres being such that the minimum air velocity within the mixing chamber will be substantially 5000 feet per minute, thereby setting up an intense turbulence therein to thoroughly mix the solid material with the air.

7. In combination with a hopper for finely divided solid material, a carburetor for mixing said material at atmospheric pressure with air above atmospheric pressure, comprising a cylindrical feed throat having a bore communicating with the hopper; shaft extending through said bore; a conveyor flight on the shaft terminating adjacent the discharge end of said bore, the periphery of said flight slidably engaging the walls of said bore; the outer endof said bore being internally beveled to form a valve seat; an annular wall around and spaced from the feed throat and forming an annular air distribution chamber closed'at both ends; a casing having an internal hubportion forming an annular mixing chamber contiguous to the outer end of the distribution chamber and beyond the said valve seat; a bearing for the shaft in the said hub; a resilient valve on said shaft within the mixing chamber and having a beveled periphery normally seating upon and closing the valve seat; the outer end of the distribution chamber having an annular series of louvres therein inclined in the same direction and discharging into the mixing chamber; a tangentially disposed inlet into the distribution chamber for air under pressure; and a tangentially disposed outlet from the mixing chamber.

8. In a combination as set forth in claim '7, said louvres being disposed at an acute angle to the swirling movement of the air in the distribution chamber, and being of such combined area that the air volume and pressure of the swirlin air will immediately remove the material as it is discharged past the said valve, the and and material swirling within the mixing chamber before passing through the said outlet.

9. In a combination as set forth in claim '7, the combined area of louvres being such that the minimum air velocity within the mixing chamber will be substantially 5000 feet per minute, thereby setting up an intense turbulence therein to thoroughly mix the solid material with the air.

10. In combination with a hopper for finely divided solid material, a, carbuertor for mixing said material at atmospheric pressure with air above atmospheric pressure, comprising a cylindrical feed throat having a bore communicatingwith the hopper; a shaft extending through said throat; a conveyor flight on said shaft terminating adjacent the discharge end of said throat, the periphery of said flight engaging the walls of said bore; the outer end of said throat being internally beveled to form a valve seat; an annular wall around and spaced from the feed throat forming an annular air distribution chamber closed at both ends; a casing having an internal hub portion forming an annular mixing chamber contiguous to the outer end of the distribution chamber and beyond the said valve seat; a bearing for the shaft in the said hub of the mixin chamber casing; a resilient valve mounted on and rotating with the shaft within the mixing chamber and having a beveled periphery normally seating upon and closing the valve seat; a round edged collar on the shaft interposed between the inner end of the hub and the outer face of the said valve; the outer end of the distribution chamber having an annular series of louvres therein inclined in the same direction and discharging into the mixing chamber; tangentially disposed inlet into the distribution chamber for air under pressure; and a tangentially disposed outlet from the mixing chamber.

11. In a combination as set forth in claim 10, said louvres being disposed at an acute angle to the swirling movement of the air in the dis- 1 tribution chamber, and being of such combined to thoroughly mix the solid material with the air.

JOHN BERRIEN ROGERS.

area that the air volume and pressure of the Y swirling air will immediately remove the mate- REFERENCES CITED riEll as it s discharged p the Said Valve, the The following references are of record in the air and material swirling within the mixing chamfile f this patent; ber before passing through the said outlet. 5

12. In a combination as set forth in claim 10, UNITED STATES PATENTS the combined area of louvres being such that the Number Name Date minimum air velocity within the mixing cham- 1,545,230 Bernert July 7, 1925 her will be substantially 5000 feet per minute, 2,127,693 McCanless et a1. Aug. 23, 1938 thereby setting up an intense turbulence therein go 2,355,774 Baker Aug. 15. 194A

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