US2310392A - Reversing means for regenerative furnaces - Google Patents

Description

Feb. 9, 1943. v. D. CAMPBELL ETAL REVERSING MEANS FOR REGENERATIVE FURNACES Filed Jan. 9, 1941l 4 Sheets-Sheet l Filed Jan. 9, 1941 4 Sheets-Sheet 2 HIIIIIIJH H hUHlllhPlhllJllllllhJll H U Wil-LW e 55 Feb. 9, 1943. v. D. CAMPBELL ETAL 2,310,392

REVERSING MEANS FOR REGENERATIVE FURNACES Filed Jan. 9, 1941 4 Sheets-Sheet 3 Eig 6.'

Feb. 9, 1943. v, D. CAMPBELL Erm. 2,310,392

REVERSING MEANS FOR REGENERATIVE FURNACES Filed Jan. 9, 1941 4 Sheets-Sheet 4 [W @ew Z afs en awp 'eZZ A 7e aesf Wis e WZ'Z ess 5g r-f Patented Feb. 9, 1943 REVERSING MEANS FOR REGENERATIVE FURNACES Vincent D. Campbell, Rocky Hill, and Charles H.

Wise, Hartford, Conn., assignors to Hartford- Empire Company, Hartford', Conn., a

tion of Delaware Application January 9, 1941, Serial No. 373,736 3 (ilams.` (Cl. 277-5) 'I'he present invention relates to reversing mechanism for regenerative furnaces and more particularly to such mechanism usable with a furnace of this type wherein it is desired accurately to control the furnace operations, such for example as in the case of furnaces used for the making of glass.

Various types of reversing mechanism have been used in the past for controlling the operation of regenerative furnaces, particularly to control the inflow of air thereto and the exit of exhaust gases. Chief among these types is the well-known buttery valve. This type of construction was fairly satisfactory in furnaces where accurate control was not particularly desired or necessary, for example those furnaces where the air for combustion was taken in directly from the atmosphere without any control of the volume thereof, except by dampers which might or might not be adjustable. Also, in such types of furnaces the-only force effective upon the atmospheric air to draw it th'roughvthe passages provided and through the furnace was the stack draft, or some draft-impelling means effective upon the exhaust gases. Under those circumstances, if some of the atmospheric air leaked past the reversing valve means provided and directly to the stack, no seriously harmful results ensued. The stack draft was slightly reduced,

but it usually was more than adequate to provide the desired draft, so that this leakage was not considered important.

However, when a furnace of the regenerative type is to be operated to provide accurately controlled conditions, including for example the supplying of definite amounts of air under pressure, as from a fan to the regenerators of the furnace, it is possible to so operate the fan as to predetermine exactly the amount of air desired. If, under these circumstances, a part of this air is permitted to leak past an ill-fitting reversing valve and into the stack passages, it is of course wholly indeterminate how much air leaks in this manner and hence how much' actually passes through the furnace to support combustion therein. In order, therefore, to provide reversing valve means which will not be subject to this leakage and which will enable accurate furnace operation, the present invention provides certain novelstructural arrangements as hereinafter set forth.

Among the general objects of the present invention, therefore, are to provide a valve means for the incoming air and outgoing exhaust gases, which will be tightly seating, so as to permit of the accurate furnace operation, as hereinabove set forth. 4

With this general object in view, consideration can now be given to the particular conditions met vwith in connection with such reversing valve means and the particular requirements for meeting those conditions. In the first place, if the valve means to be used were always to be at or near room temperature, no great problems would exist, as expansion and contraction with resultant possible warping of the various parts would be almost non-existent. However, in the use of valves of this type at the normal operating temperature of 800 to 1000" F., or higher, the temperature of the exhaust gases leaving the regenerators and passing to the stack, considerable expansion of the parts is inevitably present and difliculties are introduced incident to the provision of tightly seating valves. It h'as been found desirable, therefore, to provide valve means which will include quite heavy castings, so as to reduce the danger of warping to a minimum. It has also been found that in some instances greater pressure of the valve onto its seat should be provided in order to effect the tight closing thereof.

Among the more specic objects of the invention, therefore, are to provide valve means of the character described wherein the clearances are such as to permit of such expansion and contraction which will probably be present.

A further object of the invention is to' provide means by which the valves may be urged to their seating positions with suiiicient force so as to insure a tight seat, and more particularly to provide an arrangement by which this seating force may be adjusted to the desired extent and preferably also wherein this seating force is resiliently applied.

Furthermore, in constructions of this type it sometimes happens that a fanvor other means used for supplying air in a positive and controllable manner will fail, due to a power failure or otherwise.

A further object of the invention, therefore, is to provide means by which the furnace may be continuously operated using air from the atmosphere drawn through the furnace by stack draft or other draft-producing means effective upon exhaust gases for use in the event the positive supply means for the air should fail.

In a furnace of the character set forth, it has been found desirable to interpose springs between the valves and the operating cable system therefor. In view of the relatively great weight of the valves and the fact that in the preferred construction-shown they are moved substantially vertically, these spring means might have to be of very large size if they were to be heavy 'enough to carry the entire weight of the valve. Furthermore, any adjustment in the force exerted by the spring means in urging the valve onto an upper seat and in controlling the effective proportion of the weight of the valve urging it toward a lower seat might have less sensitivity if the springs had to carry the, entire weight of the valve.

A further object of th'e invention, therefore, is to provide counterbalance means for sustaining a desired proportion of the weight of the valves and associated parts, thus relieving the spring means of the necessity of carrying this proportion of the weight, permitting the use of relatively lighter springs and rendering the adjustment effective through the use of the springs more sensitive.

Further objects and advantages of the present invention will become apparent from the following specification and appended claims, when taken in connection with the accompanying drawings, in which:

Figures 1 and 2 jointly illustrate the upper and lower portions respectively of a furnace reversing means in accordance with the present invention, the views being partly in vertical section and partly in elevation;

Fig. 3 is a View taken as seen from the left in Figs. 1 and 2 showing the operation of the doors for admitting air to the system if the positive air supplying means should fail;

Fig. 4 is a fragmentary view partly in vertical section and partly in elevation illustrating the means for actuating the valves and for holding them in their terminal positions, the view being taken as seen from the left in Fig. 3;

Fig. 5 is a view principally in vertical section on the line 5-5 of Fig. 4; and

Fig. 6 is a fragmentary view principally in vertical section illustrating the spring means above referred to.

As shown in the accompanying drawings, the device of the present invention is supported upon a support, preferably of masonry, including a base portion I which is provided with a pair of passages 2 leading to a stack (not shown). Supported upon the base I is a housing 3, shown as formed of sheet and structural metal parts and forming a pair of separate valve bodies or chambers 4 and 5. The passages 2 communicate with the chambers 4 and 5 at their lower portions as shown. Also, communicating with the chambers 4 and 5 are large ducts 6 and 1 respectively leading to the regenerators on the opposite sides of the furnace. The regenerators and furnace are not shown in the accompanying drawings, but may be assumed to be conventional or of any desired type. There is open communication between the ducts 6 and 1 and the interior of the valve chambers 4 and 5.

superimposed upon the housing 3 is a pair of box-like structures 8 and 9 comprising air chests which communicate with the upper portions of chambers 4 and 5 respectively. Communicating with the air chests 8 and 9 are pipes I0 and II which may be joined together by a Y-connection l2, as shown in Fig. 1. The siem of the Yconnection is indicated as a pipe I3, which is intended to lead to a source of controlled air under pressure, such as a fan (not shown) having desired accurate controls associated therewith so that the volume and pressure of air supplied through the pipe I3 may be accurately regulated.

The construction of the valve seats for each of the valve chambers 4 and 5 is identical as are also the valves and their supporting means. A description of only one of'these therefore will be given.

As shown in Fig. 2, an annular casting I4 is provided mounted upon the base I and serves as the valve seat for the exhaust passage from the chamber 4 to the stack passage 2 commiicating therewith. A suitable sand seal indicated generally at I5 is provided between the housing 3 and the base I surrounding the valve seat I4. The upper annular surface of the valve seat I4 is in a substantially horizontal plane as shown and is arranged to cooperate with a substantiallv horizontal annular surface of a valve disc I6. A somewhat similar valve seat member I1 is provided secured to the top wall of the housing 3 and arranged to control the flow of air into the chamber 4 by cooperation between the bottom annular surface thereof and a substantially horizontal annular surface I8 on the upper face of the valve v disc I6. It will be noted that the seal between the valve disc and both seats I4 and I1 is between substantially horizontal surfaces, so that even though there may be differential expansion of some of these parts, no binding or sticking will ensue.

Suitably secured to the central portion of the valve disc I6 is a pair of cooperating members I9 and 20 forming therebetween a cavity or socket in which is loosely received a similarly shaped but somewhat smaller member 2| secured to the lower end of a non-circular and substantially vertical valve stem 22. Thus, when the valve stem 22 moves the valve disc I6 to its seating positions in respect to either of the valve seats I4 or I1, the loose t between the member 2| on the one hand and the members I9 and 20 on the other will permit the valve disc I6 to adjustl itself to slight irregularities which may exist so as to seat tightly upon either of the valve seats I4 or I1. Rotation of the valve disc I6 about the longitudinal axis of the valve stem 22 is prevented by forming a recess in the member 20 into which the non-circular end of the valve stem 27 loosely projects.

The valve stem 22 may be square, as shown and may be guided for substantially vertical movement between two pairs of rolls 23 and 24, these rolls preferably being cylindrical and having flanged ends extending over the sides of the valve stem 22 so as to center it. The rolls 23 are supported in suitable brackets 25 which are carried by a transverse structural member 26 suitably secured in the box or housing forming the air chest. The rolls 24 are similarly carried by brackets 21 suitably secured to the upper wall of the air chest 8. Provision is preferably made for the adjustment of the brackets 25 and 21 in respect to their supports, preferably in two directions at right angles to one another as by pro viding slots as shown at 28 in the bracket members in directions extending from right to left in the plane of the drawings, Fig. 2, and by providing similar elongate slots extending at right angles to the plane of the drawings in the supporting means, as in the member 26. In this way, the brackets 25 and 21 may be suitably adjusted to adjust the position of the valve stem 22, this adjustment being secured by the bolts which hold the brackets 25 and 21 to their respective supports.

The stem 22 passes through a suitable stuing box or equivalent means, shown at 29, to prevent leakage of air at this point during the normal operation of the furnace.

Each of the valve bodies or chambers 4 and 5 may be provided with a suitable manhole, as shown at 30, having a cover 3| thereon which may in turn be provided with an observation aperture 32 suitably provided with a closure, as indicated in dotted lines, this providing both for observation and for access into the interior of the valve chamber.

A connecting or cable means extends from one of the valve stems 22 upwardly, around an actuating mechanism and thence down to the other of the valve stems. This cable means includes an intermediate portion comprising a sprocket chain 33, which is trained over a pair of sprockets 34 and 35. Intermediate each end of ,the sprocket chain 33 and the adjacent end of each valve stem is a turn buckle 36 and a spring means 31, as best shown in Fig. 1. As shown, each end of the sprocket chain 33 is connected to one end of a turn buckle 33 and the other end of the turn buckle is connected to the piston of the spring means 31. The lower end of the cylinder portion of the spring means 31 is pivotally connected to the upper end of the valve stem 22.

In view of the relatively large size of the parts and for accessibility, it may be found expedient to place the actuating means for the valves upon a floor above that where the valves and their chambers previously described are located. As shown in theaccompanying drawings, this upper floor is generally indicated at 38 and is provided With suitable apertures through which the chain 33 and parts rigid therewith may pass, as illustrated in dotted lines at the right in Fig. 1 and also in Figs. 4 and 5. Supported upon the iloor 38 and preferably concentric with the apertures therethrough are a pair of hollow supporting members 39 which may be secured together and spaced apart by a compression member 46, as shown. The sprockets 34 and 35 are suitably mounted in, brackets secured to the upper end portions of the hollow supporting members 33.

IIhe internal construction of both spring means 31 are similar to the other, this construction being shown particularly in Fig. 6. As seen in that figure, the spring means comprises a cylinder portion 4I secured at its lower end by a pivotal connection at 42 to the upper end of the square valve stem 22. A suitable head 43 may be threaded upon the upper end of the cylinder 4I and has an aperture centrally thereof through which passes a piston rod 44, the upper end of which is secured to the lower end of the turnbuckle 36, as shown in Figs. 1 and 5. The lower end of the piston rod 44 carries a piston 45, which as shown is separated from the head 43 by a plurality of concentrically arranged compression springs, generally indicated at 46. As shown, three springs are used, although the numbermay be greater or less, depending upon the strength of springs which it is desired to employ. In the construction shown, therefore, the springs 46 will support a part or all the weight of the disc I6 and associated parts, depending upon whether or not a counterbalancing means is used, as hereinafter to be described. It will be understood that in the event a counterbalancing means is not used, the springs 46 will have to be somewhat stronger than when counterbalancing is employed.

Means are provided for moving the valve discs I6 in reciprocal directions by driving one of the sprockets 34 or 35, the former being shown as arranged to be driven. While it is contemplated that suitable automatic or mechanically driven means may be used for this purpose, there is specifically disclosed a manual means. For this purpose, the sprocket 34 is mounted on a shaft 41, Fig. 5, which is suitably journaled in brackets supported upon the upper end of the hollow support 39. There is secured to one end of the shaft 41 alarge hand wheel 48 for rotating the shaft and moving the valves. Also secured to the shaft 41 adjacent to the hand wheel is a two-way ratchet wheel 49, having for this purpose substantially square teeth. Pivoted upon an upper bracket extension 50 carried by the l support 39 is a double or two-way pawl member 5I arranged to engage a wheel 49 to prevent its movement in one direction or the other in accordance with the position of the member 5I. The member 5I has secured thereto a pair of laterally extending handle members 52, Figs. i and 4, and also has an upwardly extending arm 53 carrying a weight 54.

The operation of the parts thus far described is as follows: With the parts in the position shown in Figs. 1 and 2, air will flow from the pipe I3 through the left-hand branch of the member I2, thence through the pipe I0 and the air chest 3 to the valve chamber 4 and thence through the duct 6 to the regenerators on one side of the furnace and into the furnace to support combustion therein with the iiame traveling from left to right. Products of combustion flow from the furnace through `the other regenerator, thence through the duct 1 to the chamber 5, and thence through the right hand passage 2 to the stack. Air is prevented fro-m leaking from the air chest 9 past the right hand valve, Fig. 2, and thus is prevented from passing directly to the stack. Air is also prevented from passing from the interior of the valve chest 4 past the valve plate I6, shown at the left in Fig. 2 to the left hand stack passage. Thus, all the air supplied through the pipe I3 is required to pass through the furnace, so that this amount of air will be the same as that supplied to the furnace for supporting combustion therein. Thus it is possible accurately to control the furnace operation.

The valve plate I6 at the left in Fig. 2 is tightly seated upon the valve seat I4, this seating being under the pressure due to the weight of the valve plate and associated parts and less the Weight of the counterbalance associated with this valve, if provided as hereinafter to be described. However, the parts will function without such counterbalance, assuming sufficiently strong springs 46. inasmuch as the chain 33 is rigidly supported from the sprocket 34, which is locked at this time by the ratchet meansv 49-5I in the position as shown in the accompanying drawings, all the parts rigid therewith will be suoported from above; that is, the turnbuckle 3S, at the left in Fig. l, and the piston rod 44 and piston 45 of the spring means 31 at the left in Fig. 1. Therefore, the pressure effective upon the valve plate I6 causing it to seat upon the valve seat I4 will be determined jointly by the characteristics of the springs 46 and the adjustment of the turnbuckle 36 at the left in Fig. l.

The valve at the right in Figs. 1 and 2 within the chamber 5 will be urged onto its seat by a force depending upon the weight of the valve and associated parts and the amount of compression on the spring means 31 at the right in Fig. 1,

which is determined by the adjustment of the turnbuckle 3B at the right. Assuming therefore that there are no counterbalances for the valves, as hereinafter to be described, and assuming that the distance between the valve seats I 4 and l1 for the two chambers 4 and 5 to be the same, it will be seen that the seating pressure of the two valves in their upper and lower positions may be adJusted within relatively wide limits. It has been found in practice that this construction is adequate and very efcient in effecting reversals of a regenerative glass furnace wherein the combustion was accurately'controlled by the use of determined amounts of air under pressure supplied to the furnace.

When it is desired to reverse the furnace, the supply of fuel is cut ofl, the two-way ratchet means 5| moved from one side to the other and the wheel 48 rotated to reverse the position of the valves, thus bringing the left-hand valve disc I5 into position upon the upper valve seat I1 and bringing the right-hand valve disc into seating position on the lower valve seat I4. Fuel is then started in the opposite direction, as will be understood by those skilled in the art. Once the valves have been seated with desired pressures, the ratchet member 5I is moved to the appropriate position to maintain the valves in the positions to which they have been moved, the spring means 31 serving to retain the valves seated with the desired amount of force.

In the event that anything should occur causing a failure of the means for supplying air through the pipe I3, such for example as a power failure, means are provided for permitting the continued and substantially uninterrupted operation of the furnace (but without the accuracy of control) using air from the atmosphere, as is usually done in operating regenerative furnaces. For this purpose, air chests 8 and 9 are provided with lateral openings closed by doors shown at 55 and 56 respectively, these doors being preferably hinged at the top as shown in Fig. 3 at 51. In order to retain these doors tightlyclosed, they are each provided with arms 58 carrying at their outer ends structural members 59 arranged to support a plurality of weights 60. 'Ihe weights B0 will normally operate by gravity to keep the doors 55 and 56 tightly closed against a suitable seal to prevent the iiow of air in either direction through the openings closed by these doors. In the event the positive supply of air should be cut oir, it ls desired to open these doors simultaneously. For this purpose, the members 59 have connected thereto ropes or cables BI including length-adjusting turnbuckles as shown, these cables being trained over sheaves 62 and under sheaves 63, and both being connected to the lower end of a substantially vertically disposed threaded member 64, Fig. 1. The ropes or cables 6| pass through an aperture in the floor 38 for this purpose. The member 64 passes through the horizontal portion of a bracket 65 supported upon the door 38 and has threaded thereon above this portion a nut 66 which is provided with a pair of operating handles 61. Thus by rotating the handles 51 to rotate the nut 56, the member B4 may be raised to raise the doors 55 and 56 simultaneously. Upon reverse motion of the nut 56, the doors 55 and 56 will be closed by the weights 60 and the weights of the parts.

In some cases, it may be desired that a part of the weight load of the valve discs I6 and associated parts be taken ofi the associated springs 46. For this reason, counterbalance for a selected part of this weight load may be provided for each of the valves. Another desirable effect oi' the provision of this counterbalance is that it permits the use of lighter springs and hence permits a more delicateadjustment of the force exerted by those springs upon the valve discs in controlling the force tending to retain the valve discs onto their seats, as previously described. A further desirable result of the use of a counterbalance is that by enabling the .use of lighter springs, it also permits the use of smaller springs and hence of smaller parts throughout, including the spring housings, shown in Fig. 6, the apertures through the floor 3B shown in detail in Figs. 4 and 5, and the hollow supports 39 shown in those figures.

In order to provide such a counterbalance, one or more cables, such as shown at 68, Fig. 1, are secured to each valve stem or to each spring housing member 4l connected thereto and pass upwardly over sheaves 69, thence over other sheaves 10, and are connected to suitable weightcarrying means 1l, which may have a desired number of weights 12 placed thereon. The weight carrying means and/or the weights themselves may be arranged for suitable movement in guides indicated at 13, these guides as shown being secured to the housing 3 or the casings 8 or 9, or both. Inasmuch as the counterbalancing means for the two valves are identical, only one has been described. The number and weight of the counterweights 'l2 used will govern the proportion of the weight load of each valve disc and its associated parts, which is carried by the counterbalance and consequently the complementary proportion which is effective to compress the springs 46 associated with this valve. This renders the adjustment of the seating pressure of the valve on its upper and lower seats by the turnbuckle 36 more sensitive and results in the various desirable features above set forth.

While but one specic embodiment of the invention has been illustrated and described here in, it will be understood that various changes may be made therein without departing from the spirit of this invention and within the scope of the appended claims, which are to be construed as broadly as the state of the prior art permits.

We claim:

l. A reversing valve for use with a regenerative furnace comprising a valve body having a port adapted to connect with a source oi' air under pressure, a second port adapted to connect with a regenerative furnace and a third port adapted to connect with a stack, said first port and said third port being located opposite one another in vertically spaced portions of the valve body, a valve seat associated with said first named port, a second valve seat associated with said third port opposite the first valve seat, a valve plate in said valve body having a seating portion on one face thereof arranged to cooperate with one oi' said valve seats and a seating portion on its opposite face arranged for cooperation with the other of said valve seats, a substantially vertically disposed, non-circular stem for said valve plate, a loose, self-centering connection between said stem and its associated valve plate, at least two pairs of rollers for guiding said valve stems, means mounting each of said rollers for adjustment in two directions at right angles to one another to provide for the adjustment of said valve stem for centering said valve plate in respect to its seat, cable means for operating said valve stem and including a sprocket chain portion, a

sprocket about which said sprocket chain portion passes, means associated with said sprocket for moving it to move said chain and hence to move said valve plate in opposite directions, spring means interposed in said cable means ntermediate said sprocket chain portion and said valve stem, said spring means including a piston and cylinder and springs therebetween so constructed and arranged that the Weight of said valve plate tends to compress said springs, an adjustable turnbuckle interposed in said cable means intermediate said spring means and said sprocket chain to provide for the adjustment of the length of said cable means for said valve plateI and two-Way ratchet means constructed and arranged to lock said cable means at each end of its movement so as to provide for the seating of said valve against opposite seats in said valve chamber and With predetermined adjustable pressure for said valve on its seat.

2. Apparatus in accordance with claim 1 comprising in addition an air chest connected to said first named port of the valve body and having a port adapted to connect with a means for supplying controlled air under pressure thereto, said air chest having an additional port for connecting the interior of said chest to the atmosphere, a pivoted door closing said last named port, weights associated with said door and tending to hold-said door in closed position to close communication between the interior of said air chest and the atmosphere, a cable connected to said door for opening it against the action of said Weights, sheaves about which said cable is trained, and a lifting means comprising a threaded rod and a nut threaded on said rod and prevented from movementl in a direction longitudinally of said rod, said nut having a handle thereon for turning it to move said rod endwise to open said door to provide free communication between the atmosphere and the interior of said air chest so as to permit the continued operation of the furnace in the event the controlled air supplying means goes out of operation for any reason.

3. Apparatus in accordance with claim 1 comprising in addition cable means secured to said valve stem at a point between said stem and said spring means, sheaves about which the last named cable means is trained, and a counterweight secured to said cable means and constructed and arranged to counterbalance a predetermined proportion only of the Weight load of the movable portions of said valve so as to relieve said spring means of the counterbalanced portion of this Weight load, whereby to permit the use of relatively lighter springs than would be required if the springs had to carry the entire weight load of the valve and associated parts.

VINCENT D. CAMPBELL. CHARLES H. WISE.

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