US1978191A - Regenerative furnace - Google Patents

Description

5. A. FORTER Oct. 23, 1934.

REGENERATIVE FURNACE 1934 4 Sheets-Sheet l NN NN QN @Nl NN WN NN Filed Feb. 26

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Oct. 23, 1934. s. A..FORTER 1,978,191

)l REGENERATIVE FURNACE Filed Feb. ze, 1934 4 snetS-sheet 4 o YH INVENTOR f/f//l /f//f/,//f//fl//f//f/f//z//////////////////// Patented Oct. 23, 1934 UNITED STATES PATENT GFFICE REGENERATIVE FURNACE Pennsylvania Application February 26, 1934, Serial No. 712,988

Claims.

This invention relates to a regenerative furnace suchas an end-fired regenerative furnace for melting glass. More particularly, this invention relates to the regenerative chamber of a 5 furnace arranged for the reversal of ow of gases through the regenerative chamber, so that during one period the waste gases pass through the chamber to give up heat to checkerwork disposed therein, and during another period the incoming air is heated up by passing through the highly heated checkerwork in the chamber.

In the conventional type of regenerative chamber the checkerwork is built up in a single unit without provision for uniform distribution of gases through the checkerwork. Moreover, the capacity of a regenerative chamber is usually computed on the basis of a certain content or mass of checkerbrick; andthe checkerbrick is distributed in uniform fashion in the regenerative chamber.

I have discovered that the efficiency of a regenerative chamber can be considerably increased by a novel arrangement of checkerwork, whose purpose is to provide for uniform distribution of the gases passing through the checkerwork. It is of advantage to arrange the checkerbrick in banks, with equalizing spaces provided between the banks for redistributing the gases on leaving one bank of checkerbrick and entering the next successive bank. 'I'hese redistribution spaces rectify a tendency toward acceleration of flow through certain passages between checkerbrick at the expense of other slightly obstructed passages. In other words if, due to some fault in the disposition of brick in the first bank, there is a decrease in the flow through a certain portion of the bank, the redistribution space permits these inequalities to be eliminated as the gases pass from the first bank to the second, and so on.

A further feature of the invention, which has markedly improved the efficiency of the regenerative chamber, has as its basis the principle that the gases change in temperature in moving from the intake end of the regenerative chamber to the outlet end, and with this change in temperature there is, of course, a change in volume. This means that if, for instance, the gases increase in volume by a third in moving from the intake end to the discharge end of the regenerative chamber, the greater volume' requires that in order to avoid a corresponding increase in velocity there be a compensating increase of a third in the eective ow opening through the last bank of checkerwork as compared with the rst bank of checkerwork in the series. In the conventional type of checkerwork, in which no account is taken of this decrease or increase in volume of the gases, there is an acceleration or deceleration of 'the gases. From the principles of operation of a regenerative furnace, it will be apparent that the highest velocity in the conventional regenerative chamber is attained in the hottest portion of the checkerwork.

My invention contemplates progressively restricting the effective flow opening through the cooler portions of the regenerative chamber. By building up the checkerwork with more closely arranged checkerbrick, the greatest capacity (i. e. greatest mass) of checkerwork is provided where the largest temperature differential between the two periods (heat storing and heat yielding) occurs. Moreover, instead of accelerating the gas flow in the hottest portion of the regenerative chamber, I obtain a more even velocity of gas iiow from the intake end to the outlet end of the regenerative chamber.

It is to be presumed that from a theoretical point of view the effective ow opening through the checkerwork should continuously change from one end of the regenerative chamber to the other if a perfectly` even rate of flow is to be obe tained. However, the practical obstacles to be surmounted in doing this would render the cost of such a construction prohibitive; and, moreover, as above pointed out, the redistribution passages are of advantage in equalizing gaseous flow through diiferent portions of a bank of checkerbrick. Accordingly, banks of checkerbrick are the most practical embodiment of my invention at present known to me.

In the accompanying drawings in which are shown several illustrative embodiments which my invention may assume,

Fig. 1 is a longitudinal vertical section on line I-I of Fig. 2 through an end-red glass tank furnace of the regenerative type, parts being broken away to shorten the length of the figure;

Fig. 2 is a horizontal sectional view taken on line II-II of Fig. 1 of the regenerative furnace shown in Fig. 1;

Fig. 3 is a transverse vertical section in two planes through the regenerative chamber, the left half of the ligure being in the plane of the downcomer and showing the first bank of checkerbrick, and the right half of the figure showing in elevation the second bank of checkerbrick;

Fig. 4 is a transverse vertical section through the regenerative chamber and taken similarly to Fig. 3 in two planes, the left half of the ligure showing in elevation the third bank of checkerbrick and the right half of the 'gure showing in elevation the fourth bank of checkerbrick;

Fig. 5 is a longitudinal vertical section through a regenerative furnace similar to the furnace shown in Fig. 1 but having the regenerative chamber in two superposed tiers;

Fig- 6 is a. vertical cross-section in two different planes through the regenerative chamber, the plane of the left half of the figure being indicated by the line VIA-VIA, and the plane of the left half of the figure being indicated by the line VIB-VIB of Fig. 5; and

Fig. 7 is a longitudinal vertical section through a regenerative furnace similar to the furnace shown in Fig. 1 but having the regenerative chambers arranged in parallel vertical tiers.

The regenerative furnace shown in Figs. 1, 2, 3 and 4 is an end-fired glass melting furnace. As the invention has broad application to regenerative chambers in general and is not limited to an end-fired regenerative furnace, the details of the glass melting furnace indicated in general by the numeral 10 need not be Agiven in the present specification. As is true of the conventional type of continuous regenerative furnace, the flow of gases through the parallel regenerative chambers is periodically reversed, the hot waste gases being delivered to the regenerative chambers alternately to heat up the checkerwork therein, and the incoming air being heated up by the highly heated checkerwork contained in the other regenerative chamber. Thus, referring to Fig. 2, the products of combustion circulated over the surface of the glassin the tank 10 may sweep out through the port 12 and enter the regenerative chamber 13 by way of the downcomer 14. 'I'he air admitted to the regenerative chamber 16 becomes highly heated in passing through the checkerwork and is delivered through the downcomer 1'7 to the port 18 so as to pass over the fuel inlet ports 19 and mix with the fuel for combustion in the glass furnace 10. After a period of operation in which flow takes place in the one direction, the valve 21 controlling the connection to the stack is operated to connect the regenerative chamber 16 to the stack, and the direction of circulation of the gases is reversed.

This method of operation and construction of a regenerative furnace is conventional except for the arrangement of the regenerative chambers themselves. In the first place, the checkerbrick are arranged in banks, four such banks being shown in elevation in Figs. 3 and 4. Between the banks I provide equalizing spaces 22 which per mit redistribution of the gases passing from one bank to the next. Thus, if the bank of checkerworknearest the downcomer deteriorates due to disintegration of some of the checkerbrick by the corrosive action of the hot gases, the flow in a portion or portions of the bank may be augmented at the expense of other portions of the bank. This lack of uniformity of flow is not carried clear through the entire regenerative chamber, as the redistribution space 22 between this bank and the next permits of an equalizing action.

In the second place, it will be noted from Figs. 3 and 4 of the drawings that the checkerbrick' 24 in the rst bank is more widely spaced than the checkerbrick 25 in the second bank (shown on the right side of this figure). Moreover, the greater spacing of the brick means a decreased mass of the checkerbrick in the bank nearest the downcomer as compared with the masses in succeeding banks, the mass of checkerbrick increasing and the effective ow opening through the bank decreasing 'progressively from bank to bank toward the stack end of the regenerative chamber. Thus, it is apparent from an inspection of Figs. 3 and 4 that the checkers 24 are more widely spaced than the checkers 25; and similarly that both of these are more widely spaced than the checkers 26; while the checkers 2'7, which are the closest to the stack, are 'thev most closely spaced of all.

An important advantage of this disposition of the checkerbrick is that the largest capacity (i. e. mass per unit volume) of the checkerbrick is concentrated where there is the greatest temperature differential between the two periods of operation of the chamber. The waste gases passing through the chamber toward the stack gradually heat up the checkerwork, `until just prior to the operation of the valve 21 to reverse the furnace, the gases issuing to the stack may have a temperature from 700 to 800 F. Upon reversal, the incoming air contacts with the ,checkers 27 which are but slightly below the temperature above mentioned as applying to the issuing stack gases. Remembering that the largest capacity or mass per unit volume of checkers is concentrated at this point where there is this large temperature differential, it will be apparent that the arrangement which my invention provides works for a considerable improvement in efficiency. Moreover, the part of the regenerative chamber WhereA the checkers 24 are disposed is the hottest; and by arranging the checkerwork in accordance with my invention, the velocity of the gases flowing to or from the furnace through this part of the chamber is modified from the high velocity inherent in the conventional arrangement of checkerwork so as to be substantially the same as in other parts of the regenerative chamber.

The disposition of the regenerative chamber in a single tier as embodied in the construction shown in Figs. 1, 2, 3 and 4 affords advantages peculiar to this construction. It eliminates considerable excavation; and moreover it makes the peep holes and clean-out doors considerably more accessible. This means that the men charged with the inspection and repair of the regenerative chamber are more apt to do a thorough job; as it is easier to get at the openings leading to the checkerwork to inspect or to clean the chamber, or even to replace some of the checkerwork.

It is not essential that the regenerative chambers be disposed as shown in Figs. 1, 2, 3 and 4, however. For instance, the regenerative chambers may be disposed in tiers as shown in Figs. 5 and 6. In this embodiment the glass tank furnace 10 is connected by downcomers 30 to the regenerative chambers 31 and 32 disposed beneath the melting tank. Each chamber comprises superposed tiers, the checkerwork being arranged in banks as before. Fig. 6 shows the banks 34 and 37 of checkers which are closest to the downcomer and the stack respectively, these banks being disposed in the regenerative chamber 32. The portion of Fig. 6 which is in the plane of the section line VIA- VIA shows banks 35 and 36 of checkerwork which are respectively in the upper and lower tier, and which are intermediate (functionally) the end banks of the regenerative chamber. It is, of course, obvious that the banks 35 and 36 are in the regenerative chamber 31, and that banks corresponding to banks 34 and 3'7 will be in this same chamber.

In this embodiment, as in the first embodiment, the checkerbrick in the bank 34 is more widely spaced than the checkerbrick in the bank '35, and so on through successive banks. Moreover, capacity of the checkerwork, or in other Words the mass per unit volume is greatest in the bank nearest the stack and becomes progressively smaller in successive banks as the downcomer is approached. Accordingly, the mass of checkers per unit volume decreases progressively from the colder end to the hotter end of the regenerative chamber while the effective iiow opening through the checkerwork progressively increases from the colder end to the hotter end of the chamber.

In Fig. 7 is shown an embodiment of my invention in accordance with which the regenerative chambers are arranged in parallel vertical tiers. The glass melting tank 10" is heated by an endfired regenerative furnace connected to the tank through downcomers of which one is shown at 40. But one of the regenerative chambers is shown; and the checkerwork is arranged therein in successivet banks 41, 42, 43 and 44. Each bank of checkerwork is supported on a sprung arch 45 which is provided with openings 46 arranged to coincide with certain of the checker flue openings. The bricks in the bank 41 are more widely spaced than the bricks in the bank 42, and this decrease in spacing is carried progressively through succeeding banks to the end of the chamber. Accordingly, in this embodiment, as in the other embodiments, the spacing of the bricks is progressively increased from the colder end of the regenerative chamber to the hotter end thereof.

In the embodiments of the invention shown in Figs. 5, 6 and '7 the cross-sectional area of the regenerative chamber within which the several banks are disposed is not uniform. Accordingly, while the capacity or mass of checkers per unit volume is greatest in the bank nearest the ue,

-, the effective flow opening through the bank of checkerwork nearest the flue is still more restricted than is accomplished merely by decreasing the spacing ofthe checkers` In some installations where it is desired to have a large capacity of checkerwork adjacent the flue, it may be found more desirable to use a chamber of uniform dimensions throughout as in Fig. l, whereas in other installations where it is desired to increase the rate of iiow of the gases in the bank adjacent the flue without concentrating too great a mass of checkerwork in this bank, the cross-sectional area provided for accommodating the last bank or banks may be smaller as in the embodiments shown in Figs. 5, 6 and 7.

In all three embodiments the arrangement of the checkerwork is favorable to a more even distribution of gaseous flow; and both the provision of the redistribution spaces and the progressive change in the spacing of the checkerbrick promote the increased eciency of the regenerative chamber.

1. In a regenerative furnace, a regenerative chamber and banks of checkerwork arranged therein for unidirectional flow of gases in either of opposite directions through said banks successively, adjacent banks of checkerworkr being separated by equalizing spaces for redistribution of the gases in passing from one bank to the next and the effective flow openings through the banks being progressively increased from the colder end to the hotter end `of the chamber.

2. In a regenerative furnace, a regenerative chamber having a tier with checkerwork arranged in banks therein for unidirectional ow of gases toward either of the opposite ends of said tier through said banks successively, adjacent banks of checkerwork being separated by redistribution spaces and the effective flow openings through the banks being progressively varied from one end of said tier to the other.

3. In a regenerative furnace, a regenerative chamber in a single horizontal tier and banks of checkerwork arranged therein for the horizontal flow of gases in either of opposite directions through said banks successively, adjacent banks of checkerwork being separated by equalizing spaces for redistribution of the gases in passing from one bank to the next and the eiective ilow openings through the banks being progressively increased from the colder end to the hotter end of the chamber.

4. In a regenerative furnace. a regenerative chamber having a vertical tier with checkerwork arranged in banks therein for vertical ow of gases in either of opposite directions through said banks successively, superimposed banks of checkerwork 115 vbeing separated by redistribution spaces, and the SAMUEL A. FORTER.

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