US2387400A - Stoker gas back - Google Patents

Description

Oct.' 23, 1945. FQ G. JULYAN STOKERGAS BACK Filed May 19, 1944 v INVENTR. i fied flgdw umm,

#FFW/ver l' Patented Oct. 23, 1945 STOKER GAS BACK Fred G. Julyan, Euclid, ohio, assignor to Pocahontas lFuel Company Incorporated, New York, N. Y., a corporation of Virginia Application May 19, 1944, Serial No. l536,393

2 Claims. (Cl. 110-44) This invention relates to coal stokers and particularly to such stokers of the underfeed type.

The objectof the invention is to provide a system for feeding, heating and burning of the coal and disposing of the ashes, which will automatically intercept and draw oi any volatiles develvoping in the coal feed adjacent the burner.

Further objects of the invention, particularly in the special construction of portions of the mechanism 'to draw oii the volatiles into the space under the grate will appear from the followingt description taken in connection with the `accompanying drawing, in which Fig. 1 is a vertical sectional view of typical Stoker mechanism embodying the invention, and

Fig;I 2 is a horizontal sectional view taken on line 2--2 of Fig. 1. In the stoker shown the coal tube is continuedlto the leftybeyond the retort Ras the ash tube 5a`and the coal worm 6 in cooperation with the reverse flights 'I feed the coal up into the retort R and the worm shaft carries the disk 8 separating the co'al and ash portions of the tube, the ash flights 9 receiving the ash from above and conveying it outward toward the left preferably to an ash seal substantially secure against the entrance of air.

The retort R has a lower base portion in horizcntal separated sections carrying the upper radiallyformed tuyre blocks with tuyre openings I3 receiving the air supply from the air chamber I2 within the lower sections of the retort.

An ash table I4 is rotatably mounted on the retort and carries a grate I5, the construction being similar to that shown generally in the Julyan and Schweickart Patent No. 2,321,389 of June 8,

1943. A desd ring ls, l1 is Supported by its brack-` et arm 2I from the lugs 22 of the retort base and is recessed at 23 to t the `dead plateD forming the separation between'the combustion chamber F and the space below the dead plate D. Rotation of the ash table I4 carries the ashes around to the discharge I8 passing the ashes down through the opening I 9 in the ash tube ring 2li.

The ashes accumulating `in the dead ring I6, I'I fill the lower portion thereof and act as a substantial seal against the entrance of air from the space below the dead plate D into the area under the grate so that there is comparatively little air leakage, and the combustion chamber due to the chimney draft is at a lower pressure.

'I'he coal passing up into th'e retort is heated so that the coal being fed tends to have some of its volatiles vaporized in a manner causing them to gas back along the coal feed. In the stoker of this invention a by-pass is provided through. the vertical portion I1 of the dead ring I5, I'! by means of an inclined orifice 3l and a U-shaped hood or cover extending downward and outward and terminating in the inclined lip 26 having a vertical edge and sides 21 fitting Within the gas back tube 28 with the base portion 29 fitting the top of the coal tube `5. The bore 32 of the gas back tube 28 is centered over the by-pass ori- `lice of the coal tube 5 to provide a free passage for coal gases through the orifice 38 and bore 32, hood 25 and outlet 3| into the space underneath the grate I5. A downward extending ledge from the dead ring I5, I'I closes the space between the dead ring and the adjacent portion of the gas back tube.

In this way a draft of air and gas is carried up from the top of the coal tube just at the periphery of the dead ring and close to the area of volatilization of the coal vapors, there also being a slight indraft of air from the outer portion of the coal tube so that leakage of the coal gas is eiectiveliT prevented. By virtue of this arrangement, the coal tube 5 is always under a minus pressure and gases are being drawn through the dead ring l1, grates I5 and the fuel bed in the combustion chamber F. l

The outlet 3l through the dead ring and the accumulating ho'odfor this -outlet are preferably formed with the dead ring'during casting but may involve a separate construction. The gas back tube 28 and its base 29 form a separate unit readily inserted in place and removable without disturbing any of the other parts. It is only necesi sary to slide this gas back tube lengthwise on the p coal tube 5 to open up the by-pass for inspection.

The construction tends to be self-cleaning. Any ashes nding their way up and over into the bypass will fall down into the coal supply and be carried on-into the retort with the coal. The bypass is of generous cross section and is kept at a temperature sufficiently high to avoid condensation of the volatiles of the coal gas so that these gases are kept from accumulating within the gas back passage by condensation.

No extra parts beyond the gas back tube itself are required and the construction is inexpensive, rugged and readily positioned and removed.

I claim:

1. In a stoker construction having a retort and a grate around theupper portion of said retort, a dead ring aroundV said retort at a lower level and forming an ash space adapted to receive ashes at the bottom below said grate, an orifice structure carried by said dead ring and opening laterally into said ash space and above the normal level of the ashes therein and below said grate, a coal tube passing beneath said dead ring and having an opening and a gas back tube extending from said opening tocommunicate with said orice structure and form a passage from said coal tube to said ash space.

2. A stoker construction as set forth in claim 1 in which the orifice structure carried by said dead ring comprises a hood formation on the dead ring and the gas back tube is carried by the coal tube in position to be moved horizontally into cooperation with said orifice structure.

FRED G. JULYAN.

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