US2594976A

US2594976A - Seal for ash hoppers

Info

Publication number: US2594976A
Application number: US158816A
Authority: US
Inventors: Lauritz E Mylting
Original assignee: Allen Sherman Hoff Co
Current assignee: Allen Sherman Hoff Co
Priority date: 1950-04-28
Filing date: 1950-04-28
Publication date: 1952-04-29
Anticipated expiration: 1969-04-29

Description

April 29, 1952 E. MYTLlNG SEAL FORASH HOPPERS Filed April 28, 1950 INVENTOR. ZAl/iE/TZ 5 MY! TING @TOPNEYS Patented Apr. 29, 1952 SEAL FOR ASH HOPPERS Lauritz E. Mylting, Merchantville, N. J., assignor to The Allen-Sherman-Hoff Company, Phila- 1 delphia, Pa., a corporation of Pennsylvania Application April 28, 1950, Serial No. 158,816

5 Claims.

This invention relates generally to the furnace art and is particularly concerned with means for preventing escape of gases between the walls of an ash-receiving hopper and the walls of a fuel burning furnace surrounding an ash discharge opening from such a furnace.

Modern steam generating plants, for example those operated by public utilities, include furnaces having combustion chambers in which solid fuel is burned and having ash discharge openings in their lower portions through which the ash may be delivered, in the solid or liquid state, into a hopper positioned therebeneath. It is desirable that gases should neither flow into nor out f of the combustion chamber through the ash discharge openings and, to prevent such flow, various expedients have been proposed to seal the space between the ash hopper walls and the furnace walls around the ash discharge openings. Such scaling is complicated by the fact that the furnace walls are heated to a much different temperature than the hopper walls and, hence, ex-

pand and contract to a different extent than do the hopper walls, and as a result of this unequal expansion and contraction, the hopper walls may not be rigidly attached to the furnace walls around the ash discharge openings.-

One solution of the problem was described in U. S. Patent No. 2,275,652, granted on March 10,1942, to Harold R. Pursel. The invention there disclosed has gone into extensive commercial use and has proven to be quite satisfactory, but it has the disadvantages that the walls depending transversely and longitudinally from the furnace were not readily protectable, by a refractory facing, against the intense heat from the combustion chamber, and flexible members were required to connect the ends of those depending walls at their ends to permit their relative movements with changing temperatures. Furthermore, it is difficult, if not impossible, to

: cool refractory material on the inner side of these depending walls.

As a result of the first named disadvantage, refractory walls of various types were used to protect these depending metal walls.

Another disadvantage was that the liquid in the trough was directly exposed to the intense heat of the furnace and, being open to the furnace, cooled solids at a rapid rate which necessitated frequent cleaning out of the trough.

The' present invention solves the problem in water-cooled by the water in the trough and in which the water in the trough is not exposed to the direct heat of the furnace and is so far removed from the ash discharge opening that the quantity of solids which can enter the trough is quite limited.

While the present invention is of perhaps greatest value in conjunction with a powdered fuel burning furnace and its hopper, with which parts it has been illustrated herein, the inven-' tion is also quite valuable with furnaces equipped with stokers of any of the various conventional kinds where the ash is in solid form as contrasted with a liquid form when it enters the hopper.

The present invention will be better understood by those skilled in the art by reference to the accompanying drawings which form a part of this specification and the following description thereof.

In the drawings:

Fig. l is a fragmentary, vertical, transverse, sectional view through a powdered fuel burning furnaceand its hopper and showing one form of seal embodying the present invention; and

Fig. 2 is a fragmentary, sectional view showing a modified form of the present invention.

In Fig. 1, l designates the lower part of a powdered fuel burning furnace having a combustion chamber 2 and an ash discharge opening 3. Opposite upstanding walls 4 of an open topped hopper are positioned to receive ashes discharged from chamber 2 through opening 3.

The seal between the furnace l and chamber 2 comprises a metal wall Ill depending from the furnace wall around discharge opening 3 and projecting into the hopper within walls 4 thereof. This endless depending metal wall Hi is provided with a refractory lining II on its inner side. At the lower end of wall I 0 an endless horizontal Wall 12' extends from within wall It] to a point some distance outside thereof and then extends upwardly as at l3. Walls "3,12 and I3 define an open topped endless trough which extends all the way around the outer side of wall H and the ash discharge opening 3. The projection M of horizontal wall l2 inwardly beyond the vertical projection of depending wall IE! affords a support for the refractory material M. It will be seen that by maintaining a quantity of water in the trough 13 the depending wall it and its refractory lining II will be watercooled and, hence, protected against the intense heat from the combustion chamber.

A metal wall i5 is secured to the hopper walls wall [3 of Fig/1.

upwardly extending inner edge 24 to act as a lining 2 4, extends inwardly therefrom and then vertically down into the trough, as at [6, between inner and outer walls It) and I3 thereof. This wall extends continuously around the discharge opening !3 and, together with the parts which are attached to the furnace and have just been described, acts as an effective seal against flow of gases either into or out of the combustion chamber through the upper end of the hopper.

Since the hopper walls never attain a temperature as high as that attained by the walls of the combustion chamber about the ash discharge opening, the hopper does not expand and contract to such an extent as do thefurnace walls. Hence, with a trough having'substantial width between walls I0 and I3, these trough-forming walls may expand and contract with the furnace walls without ever coming into contact with the depending portion IS of wall I 5.

In Fig. 2, the embodiment of the invention shownis somewhat different from that shown in Fig. '1. In'Fig. 2, the furnace I has a similar combustion chamber and discharge opening 3, a depending endless metal wall 20, quite similar to wall "l0 of Fig. '1, a refractory lining 21 on the inner side of wall similar to lining H of Fig. 1, a horizontal wall 22 similar to wall l2 of Fig. 1, and'an upwardly extending wall 23 similar to Wall'22, unlike wall l2, has an bettersupport and retainer for the refractory The hopper wall consists of an outside metai'wan 38 and a refractory liner 3! therefor. Wall3il extends horizontally, as at 32, on top of the liner SI and affords support for a channelshaped upright wall 33 which extends upwardly in telescoping relation with wall 23. The latter wall has a depending ledge 34 which telescopes with an upstanding flange 35 of wall 33 to afford a restricted passage from the interior of the hopper to the space between

walls

23 and 33, this restricted passage acting to retard the movement of fine 'solids'i'nto the liquid in the trough between wallsiil and; 23. At the upper end of wall 23, a metal wall'36 is secured and extends inwardly and then-downwardly, as at 31, to project into the'trou'gh between walls 2% and 23 and to dip into water therein. The apparatus of Fig. 2

issubstantially the same as that described above in 'connection with Fig.1.

iFrom theforegoing description, it will be understood that the apparatus of the present invention has a number of'advantages. It makes it possible to provide a refractory lining for the depending'wall M or 20 and thereby permits the use of relatively'inexpensive materials for those wallswhich would not be resistant to the -,prevailingconditions in the absence of the refractory lining. 'Thepresence of the water against the outer side of these depending walls serves not only to cool" these walls and their refractory linings, but also thereby to make it possible to use thinner linings. Furthermore, since the water seal'is on the outside of the depending walls, the sealing walls [5 can be readily attached to the hopper walls and readily removed when necessary.

Since the trough is outside of the depending wall and the top surface of the Water therein is removedsome distance from the discharge opening 3, the quantity of fine solids which find their way into thehopper is considerably reduced.

Another and quite important advantage is that for a given header spacing the sealin elements can be kept a' maxirrium distance from the dis- 4 charge opening of the combustion chamber, the hopper can be made considerably wider than otherwise and the depending walls I0 may be extended far enough down into the hopper to afford space for access and inspection doors in walls l5 and 35 above the troughs.

If the depending walls- [0 or 20 are extended down far enough into the hopper, they can maintain in their shadow the troublesome water line in submerged hoppers. It will be understood that in these so-called submerged hoppers water is retained in the hopper to quench the ash and that it is somewhat difficult to maintain the lin- -ing ill-gOOd condition at the surface level of the -water due to the intense heating of the lining above the line and its much lowe temperature below thesurface of the water. By extending the present seal down far enough into the hopper to cast a shadow on the water line, the troubles with that portion of the hopper may be greatly minirnized.

Having thus described the present invention'so that others skilled-in the art maybe 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:

i. In apparatus of the class described including a fuel burning'furnace having an ash discharge opening and a hopper'pcsitioned to receive ashes from said opening, the combination of awall extending down from said furnace around said opening, a wall extending outward from the lower portion of said depending wall and then extending upwardly to form therewith-an endless open-top trough for liquid, and a wall extending inwar'dly from the hopper walls ancl downwardly into said trough to seal'the space between the'trough and hopper wall against the escape of gas .therebetween.

2. In apparatus of the classdescribe'd including a fuel burning furnace having an ash discharge opening and a hopper positioned to receiveashes from said opening, the combination of a'wall-extending down from said furnace around said opening, a refractory liningon the inner side of wall, a wall extending outward from the lower portion of said depending wall'arid 'then extending upwardly to form therewith-an endless open-top trough for liquid, and a wall extending inwardly from the hopper walls and downwardly into said trough to seal the's'pace between 'the trough and hopper wall against the escape of gas therebetween.

3. In apparatus of the class described-including a fuel burning'furnace having an'ash discha'rge opening and a hopper positioned to receive ashes from said opening, the combination of a metal wall extending down from said furnace'around said opening andinto said hopper, a'refra'ctory lining on the inner side of-said metal wall awall extending approximately horizontally outward from the lower -portion of said depending wall and then extending upwardly approximately parallel thereto to form therewith an endless opentop trough for liquid, and-a wall extending -inwardly from the'hopper walls and downwardly into said trough to seal the s'pace between the trough and hopper wall against the escapeof gas therebetween.

4. In apparatus of-the class described including a'fuel burning furnace having an-ash discharge opening and "a hopper positioned to' rec'eive ashes from said opening-the combination of a metal wall extending 'down 'fromsaid furnace around 5 said opening and into said hopper, a refractory lining on the inner side of said metal wall, a wall extending approximately horizontally out-warfrom the lower portion of said depending wall ana then extending upwardly approximately parallel thereto to form therewith an endless open-top trough for liquid, said horizontal wall extending inwardly beyond the depending wall and aifording support for said lining, and a wall extending inwardly from the hopper wall and downwardly 10 into said trough to seal the space between the trough and hopper wall against the escape of gas thereloetween.

5. In apparatus of the class described including a fuel burning furnace having an ash discharge 1;

opening and a hopper positioned to receive ashes from said opening, the combination of an endless metal wall extending down from said furnace around said opening toward the interior of said hopper, a refractory lining on the inner side of 20 said metal wall, an endless wall extending a reugl and hopper wall against Z MYLTING.

CETEZ) The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Van llckeren l Sept. 26, 1933 2,275,652 Pursel Mar. 16, 1942 2,337,634 Berry Dec. 28, 1943 2,339,235 Allardioe Jan. 11, 1944 2,339,217 lllardiee 11, 1944