US2720177A - Water seal for high pressure furnaces - Google Patents

Description

f 28 BaaBz EE Oct. 11, 1955 G. R BARBER 2,720,177

WATER SEAL FOR HIGH PRESSURE FURNACES 1/- FMEA/ACE WALL mwmmm,

WATER INLET INVENTOR. GEOPGE 7E. .BA EBEE BY )FICHE Y, WA T75, EBGEPO/V MNEA/NY A Troie/Veys United States Patent ice WATER SEAL FOR HIGH PRESSURE FURNACES George R. Barber, Drexel Hill, Pa., assignor to The Allen- Sherman-Holf Company, Wynnewood, Pa., a corporation of Pennsylvania Application August 5, 1954, Serial No. 448,049

6 Claims. (Cl. 11G-165) This invention relates generally to the art of handling gases under pressure and is particularly concerned with means for preventing the flow of gases through thespace between a powdered fuel burning furnace and its ash hopper.

Fuel burning furnaces have heretofore been provided with seals to prevent the flow of gases through spaces between the ash hopper andthe ash discharging part of the furnace. Seals of this type are disclosed in U. S. Patents Nos. 2,275,652 and 2,594,976. The seals of these patents include a trough containing water and a gas impervious curtain depending into the water with the trough being connected to the furnace or to the hopper and with the curtain being connected to the other one of those two devices.

While water seals of the types disclosed in the aforesaid patents have been found to be satisfactory in extensive commercial use, they possess certain inherent limitations. Those seals werefrst used on furnaces in which the gas pressure was low, amounting to only a few inches A of water pressure, and the depth of the water in the seal was correspondingly short. As the furnace pressures were increased from time to time, the depth of the trough in these seals was correspondingly increased by increasing the vertical dimensions of the troughs and curtains. As

the sizes of these parts increased, the seal apparatus became larger and more cumbersome untilia practical limit to the size of those parts has been reached which, however, will not accommodate the present high pressure or the higher pressures which are in prospect. So far as I know, no one has proposed a seal 'which could be used i with the present high pressures or even higher pressures and which would be compact and free from the objections of excessive size and the other disadvantages of the seals of the types disclosed in the aforesaid patents.

The present invention aims to provide a new seal for such high pressure and attains that object by a new cornbination of elements which give a new result not attainable by the elements acting separately.

Briefly stated, the present invention provides a plurality of seals each including a liquid-containing trough and a gas impervious curtain and means for creating a gas pressure in those seals which balances or offsets part of the pressure to be sealed.

The present invention will be better understood by those skilled in the art from the following specification taken in connection with theappended drawings in which:

The figure is a fragmentary, vertical sectional view showing one embodiment of the present invention applied to a furnace and its hopper.

In the figure, 10 designates a part of the wall dening the ash discharge passage from a fuel burning furnace. The wall 10 projects downwardly into the ash hopper 11 through an opening in its top.

The means for sealing the space between the wall 10 and hopper 11 includes the trough member 12, the curtain member 13 and a gas pressure producer and regulator 14.

y 2,726,177 Patented Oct. 11, 1955 The trough member 12 is positioned in the ash receiving opening of hopper 11, is connected to the hopper, ex-

tends entirely around the furnace wall and consists of a bottom wall 15 and outer, middle and inner vertical walls 16, 17 and 18, respectively, these several walls form- ,.ing outer and inner troughs 19 and 20, respectively, to

may be drawn off from the overflow trough. Water or other liquid may be brought into the inner trough 20 through pipe 23 which extends from a source of supply through a wall of hopper 11 and through the bottom wall 15 of the inner trough. Like liquid may be supplied to the outer trough 19 in a similar manner or may be piped into the upper open end of that trough.

The curtain member 13 of the illustrated seal comprises vertical, outer and inner, gas impervious walls 25 and 26 which are disposed in the outer and inner troughs 19 and ,Zll, respectively, and which are connected by a horizontal top wall 27. This member 13 is attached to the furnace wall 10 iniany suitable manner, as, for example, by a gas-tight connection of wall 28 to member 13 and to the metal shell of furnace wall 10. This wall 28 serves `to position and maintain walls 25 and 26 in vertical position between and spaced from the side walls of troughs 19 and 20.

Means are provided to create and maintain a gas pressure between walls or curtains 25 and 26 above liquid `in troughs 19 and 2l). As shown, this means comprises p comprising a vessel 33 and pipe 32 is called a bubbler for the sake of brevity.

The above-described apparatus operates substantially as follows: The troughs 19 and 20 are filled with water or other liquid and a sufficient amount of the same liquid is placed in vessel 33 to make the distance D equal to about half the pressure to be sealed, as expressed in inches of between the surfaces of the water in trough 24 on opposite sides of curtain 26 is approximately equal to distance D, i. e., about half the pressure within the furnace is offset or balanced by the column of water in the inner trough 20 above the surface of the water in that trough on the inner side of the curtain 26. The gas delivered by compressor 30 into the curtain member 13 forces liquid down in trough 19 between curtain 25 and middle wall 17 and up between curtain 25 and outer wall 16, and raises the surface of the liquid in trough 19 outside of curtain 25 to a level above the liquid on the other side of curtain 25 to an amount equivalent to about half of the gas pressure within the furnace. The bubbler serves to control the gas pressure delivered into curtain member 13 for if the gas pressure within the furnace exceeds the predetermined amount, gas from the compressor will flow through the bubbler, and if the pressure falls below the predetermined amount, gas from the compressor will ow into member 13 and will not ow through the bubbler.

In this manner, high gas pressures in the furnace may be sealed by compact apparatus of short vertical length.

For example, with a two-stage seal, such as is disclosed herein, a gas pressure equivalent to 40 inches of water can be sealed by columns of water in troughs 19 and 20 each of which columns. seals against a gas pressure of about 20/ inches of water. In other words, apparatus embodying thisv invention may seal against a gas pressure of 40 inches and yet be only a little more than 20 inches in overall vertical length.

It will be understood that more than two troughs may be VemployedV in a seal embodying the present invention and that as the number of troughs increases, the gas pressure which the device can seal may increase or the vertical height of the apparatus may be decreased.

Having thus described the present invention so that others skilled in the art may be able to understand and practice the same, I state that what I desire to secure by Letters Patent is defined in what is claimed.

`What is claimed is:

1. Apparatus for sealing a space between the walls of two members against 'ow therethrough of gas under pressure comprising a member adapted to be attached to one of said walls and deiining a plurality of vertical, open topped troughs to contain a liquid, a member adapted to be attached to the other of said walls and including gas impervious curtains depending into liquid in each of said troughs, and 'means for maintaining in the space between said curtains and above the liquid in said troughs gas under pressure equal approximately to the gas pressure to be sealed divided by the' number of open top troughs.

2. Apparatus for sealing a space between the walls of two members against flow therethrough of gas under pressure comprising a member adaptedv to be attached'to one of said walls and defining a pluralityof vertical, open topped troughs to contain a liquid, a member. adapted to be attached to the other of said walls and including gas impervious curtains depending into liquid in each of said troughs, and means for maintaining in the space between said curtains and above the liquid in said troughs gas under pressure equal approximately to a predetermined part of the pressure of the gas to be sealed, said means including a gas compressor, a bubbler containing a liquid and lines for conducting gas from said compressor into the space between said curtains and into liquid in said bubbler at a predetermined distance below the surface of that liquid.

3. Apparatus for sealing a space between the walls of two members against iiow therethrough of gas under pressure comprising a member adapted to be attached to one of said walls and defining two vertical open topped troughs to contain water, a member adapted to be attached to the )ther of said walls and including gas impervious curtains depending into water in each of said troughs, and means for maintaining in the space between said curtains and above the water in said troughs gas under pressure equal approximately to one half of the pressure of the gas to be sealed. Y

4. Apparatus for sealing a space between the walls of two members against flow therethrough of gas under pressure comprising a member adapted to be attached to one of said walls and having a bottom wall and vertical, horizontally spaced walls extending upwardly therefrom to form vertical, open topped troughs to contain Water, a member adapted to be attached to the other of said walls and having a horizontal wall and horizontally spaced, gas impervious walls depending vertically from said horizontal wall and into water in each of said troughs, said depending walls being spaced horizontally from the walls of said troughs, and means for maintaining in the space between said depending walls and above the water in said troughs gas under pressure equal approximately to a predetermined part of the pressure of the gas to be sealed.

5. Apparatus for sealing against escape of gas under pressure from a fuel burning furnace comprising an ash hopper having an opening in its upper portion, a furnace wall extending through said opening and defining an ash discharge passage, means attached to said hopper, surrounding said furnace wall and having vertical walls defining two lvertical troughs for water, means attached to said furnace wall, surrounding said wall and having two vertical, gas impervious walls depending into water in said troughs, and means for maintaining in the4 space between said depending walls and above the water in said troughs gas under pressure equal approximately to onehalf ofthe pressure ofthe gas to be sealed.

6. Apparatus for sealing against escape of gas under pressure from a fuel burning furnace comprising an ash hopper having an opening in its upper portion, a furnace wall extending through said opening and defining an ash discharge passage, means attached to said hopper, surrounding 'said furnace wall and having vertical walls deiining two vertical troughs for water, means attached to said furnace wall, surrounding said wall and having two vertical, gas impervious walls depending into water in said troughs, and means for maintaining in the space between said depending walls and above the water in said troughs gas under pressure equal approximately to one-half of the pressure lof the gas to be sealed, said pressure maintaining means including an air compressor, a line to conduct air from the compressor into the space between said depending wallsandinto a bubbler, the latter having a depth of water above the outlet of the air thereinto which is approximately equivalent to a predetermined part of the gas pressure to be sealed.

vonr Kerpely Nov. 11, 1913 Keith et al Sept. 27, 1938

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