US2173884A - Fluid control system - Google Patents

Description

Sept. 26, 1939.

w. v. SAUTER Er Al. 2,173,884

FLUID CONTROL SYSTEM Filed May 18, 1935 2 Sheets-Sheet 1 Sept. 26, 1939. w. v. SAUTER Er AL v FLUID CONTROL SYSTEM 2 Sheets-Sheet 2 Filed May 18, 1935 Patented Sept. 26, 1939 UNITED STATES PATENT OFFICE FLUID CONTROL SYSTEM Application May 18, 1935, Serial No. 22,217

15 claims.

This invention relates to uid control systems, and more particularly to systems employed to control the flow of draft air to stoker furnaces.

It is the primary object of the present invention to provide a generally improved fluid control system for stoker furnaces which prevents an excess of air from flowing through the tuyres thereof upon a reduction in the fuel bed resistance.

Another object is to provide a fluid control system for stoker furnaces which improves the distribution of air to the fuel bed whereby the latter is maintained normally uniform under all conditions of operation.

A further object is to provide each stoker tuyre with independent means for controlling the ow of air therethrough.

A further object is to provide each tuyre of a stoker with an independent air control device 20. which occupies a minimum of space and which requires a minimum of work to install.

A still further object is to provide each tuyre with an independent air control device which is self adjusting and which requires no field atten- 25 tion.

A still further object is to provide a simplifiedA Fig. 2 is a side elevational view partly in section and diagrammatic in part, of a series of tuyre blocks showing one form of air regulating device associated therewith.

Fig. 3 is a perspective view of one of the tuyre blocks shown in Fig. 2 with a portion thereof broken away to show the arrangement of the con-- trol device associated therewith.

Fig. 4 is a plan View of a tuyre block in inverted position with the control device separated therefrom.

Fig. 4E is an enlarged elevational view of the damper unit shown in Figs. 2 to 4.

Fig. 5 is a side View partly in section of a plurality of tuyre blocks showing a modified type of air control mechanism therefor.

Fig. 5 is an enlarged sectional view of one of the dampers shown in Fig. 5.

Fig. 6 is a View similar to Fig. 5 but showing 55 the air control devices in operated position,

The present invention, for the purpose of illus- 1Q.

tration, is shown applied to a Stoker of the underfeed type, although it is apparent that the invention is equally applicable to other types of stokers, as well as other apparatus wherein control of a fluid is desired. As illustrated in the 1.5:

drawings, each tuyre is provided with a damper. In some instances ,the damper controlling the air flow to one tuyre overlaps with the damper controlling the air flow to an adjacent tuyre,

and thus these overlapping dampers form comv municating passages to the tuyres. In cases Where the area of each of these communicating passages is substantially the same as the area of the tuyre openings the pressure of theair therein is substantially the same as that fiowing through the tuyres. Air is supplied to each of the tuyres from a common pressure or plenum chamber wherein the pressure remains substantially constant during operating periods of the furnace at any given rating. It therefore Will be observed that should the fuel bed over any of the tuyres develop a blow hole, or 'become abnormally porous, so as to causethe velocity of the air supplied thereto to increase, while the fuel bed over an adjacent tuyre block remains normal, thereby imposing the normal resistance to the air flowing thereto, the damper associated with the first tuyre will be subjected to a greater pressure at one side than at the other, and obviously will tend to move in the direction of the 40 lesser pressure. As the velocity of the air past a damper increases the static pressure decreases, and as a result the damper will be urged to closed position to throttle the air supply to the abnormally thin or porous portion of the fuel bed. Therefore, by this arrangement of overlapping dampers the flow of air through one tuyre is controlled, to acertain extent, by the flow of air through an adjacent tuyre.

The drawings also illustrate various arrange- 60 ments of dampers wherein the flow of air to each tuyre is independently controlled. In these arrangements one surface of each damper communicates with a passage leading to an assoiatd tuyre, while the Vother surface thereof communicates with the plenum or air supply chamber. Inasmuch as the plenum chamber pressure is always greater than the static pressure of the air in the restricted passage of the tuyres the dampers will be subjected to a differential pressure. In -such constructions the dampers may be provided with weights orbe constructed of relatively heavy material so that they will remain open until a predetermined differential pressure isimposed thereon, at which time they will move toward closed position.

It therefore is seen that should thin or extremely porous spots develop in the fuel bed the damper or dampers controlling the air thereto will close. The fuel feeding velements will then have the opportunity of build up such thin portions of the fuel bed before damage can occur to the underlying grates. As the fuel bed builds up, and therefore offers a greaterresistance to the flow of air through the associated tuyres, the differential pressure acting upon the damper or dampers controlling the air thereto will be reduced, and as a result they will move toward open position and again permit a normal quantity of air to flow to those portions of the fuel bed. The dampers, therefore, tend to maintain the fuel bed normally uniform throughout and thus prevent blowing of the fuel, as well as damage to the grates, in the event abnormally thin spots occur therein.

Referring to the drawings, the numeral I designates a stoker of the underfeed type having alternately disposed retorts 2 and tuyre rows 3. Fuel is supplied to retorts 2 from a hopper 4, and any suitable feeding device driven by a power mechanism indicated at 5 feeds the fuel gravitatng in hopper 4 to the retorts 2. A series of pushers 6 mounted in the bottom of each retort 2 is also operated by the power mechanism 5 through the connections 1. These pushers underfeed the fuel along the retorts and tuyres to an extension grate 8, which in turn overfeeds the fuel to an ash pocket 9 disposed at the rear of the stoker. It is to be understood that the invention hereinafter described is not to be limited to its application to underfeed stokers, since it is equally adaptable for use in connection with other types of stokers, as well as other apparatus wherein flow control is desired.

When the terms front and rear are hereinafter used in connection Ywith the description of the elements of the Stoker II and the associated fluid control, it will be understood that the portions of such parts extending toward the rear or ash pocket 9 of the stoker will be designated as rear, and those portions thereof extending toward the front or the driving mechanism 5' of the stoker will be designated as front,

Referring more particularly to Figs. l to 4 inclusive, which constitute the preferred embodiment of the present invention, each tuyre row 3 comprises a series of superimposed tuyre blocks III each having a rounded nose or rear portion I i, and a substantially rectangular front portion I2. The upper surface I3 of each tuyre block is substantially fiat and has a slightly beveled portion I4 extending around the noseportion thereof. The under side of each tuyre block isprovided with a series of relatively long and relatively short ribs I5 and I6 respectively, which diverge from front to rear of the tuyre block, as shown in Fig. 4, on either side of a longitudinally extending dividing rib I'I. A pair of spaced rear- War-dly diverging ribs I8 are also provided on the under side of each tuyre block which in the present instance define an inlet passage I9 for draft air. Ribs I8 terminate at the rear ends thereof in extended flat supporting portions 20. Each tuyre block has also provided on the under side thereof a pair of inclined supporting surfaces 2I which in assembly' seat upon the side plates. 22 of adjacent retorts 2. The under side of each tuyre block is also provided with a pair of widely spacedlocking lugs 253 which in assembly engage in the substantially rectangular openings or apertures 23 of the next lower tuyre block of the series. Ribs I8 extend forwardly of the front edge 25 of each tuyre block and are provided with a pair of aligned apertures 26 disposed near the lowerforward ends thereof. Draft air enters the tuyres from a common pressure or plenum chamber E? disposed beneath the stoker which in turn is supplied with air from any suitable fan mechanism (not shown) in a well known manner.

Upon reference to Figs. 2 and 3 it will be noted that an air control unit, designated generally at 30, is provided for each of the tuyre blocks I0. Control device 3!) comprises a pair of pivotally mounted damper elements 3l and 32 respectively which extend between ribs I8, and which are connected for simultaneous movement by a link 33 of any suitable construction. Damper element 3| comprises a relatively flat portion 34 terminating at its rearwardly -disposed end in an arcuate portion 35. The arcuate portion 35 makes an angle of substantially 90 degrees with the flat portion 34 and the rear surface of the former engages or is slightly spaced from the front edge 25 of its associated tuyre block I3. The front end of each damper element 3l is provided with a pair of depending apertured ears 33 the apertures of which in assembly align ywith the apertures 25 provided at the forward ends of ribs I8 and a pair of pins 37 pivotally secure damper elements 3| to the ribs I8. Damper elements 32 are also pivotally supported in any suitable manner to ribs I8 of their respective tuyre blocks, such as by a pair of pins 38. It therefore is seen that the upper surface of a damper element 3I, mounted on one tuyre block il), forms with the damper element 32 of the next higher tuyre block and ribs I8 a passage 0 which communicates with the inlet passage I8 between those tuyre blocks. By this construction all of the air entering the tuyre blocks must pass through an associated pair of damper elements 3| and 32 and thence to inlet passage I9 before it may enter the fuel bed.

Referring more particularly torFig. 2, it will be observed that the lower surfaces of damper elements 3l and the upper surfaces of elements 32 are subjected to the pressure in plenum chamber 2'I. However, since the areas of these surfaces are substantially the same, it is apparent that no movement will be imparted to said elements by this pressure. It will also be observed that the upper surface of each damper element 3I extends forwardly from the upper surface of an associated tuyre block which constitutes the bottom wall of an inlet chamber I9,while the lower surface of the damper element 32 extends forwardly of the lower surface of the tuyre block, which constitutes the upper wall of the next lower inlet chamber I9. It is also seen that inasmuch as the elements 3| and 32 of each unit are interconnected by an element 33, any movement imparted to one of said elements is also imparted to the other. Therefore, should the velocity of the air in one chamber I9 increase,

thereby reducing the static pressure operating against the upper surface of the associated damper element 3|, while the velocity of the air in the next lower chamber I9 remains substantially the same, thereby imposing the normal pressure against the lower surface of damper element 32 for that unit, it will be readily seen that since the pressure acting against the lower surface of element 32 is greater than the pressure acting against the upper surface of the upper element 3|, both of said elements of the unit will tend to move upwardly. These damper elements may be so designed that the dead weight thereof will be sumcient to hold them open for a predetermined diiferential pressure or have weights or springs associated therewith for that purpose. When this differential pressure increases due to a decrease in fuel bed resistance, the damper element 3| will move upwardly into engagement with damper element 32 of the next higher tuyre block of the series thereby throttling the flow of air therethrough. When the damper elements have thus been actuated to closed position a slight leakage of air occurs past the contacting surfaces thereof. As a result the damper elements are subjected to a differential pressure of suflicient intensity to maintain them in closed position. If no leakage occurred under these conditions damper elements 3l would drop slightly from their fully closed positions and would then be instantly actuated to closed position again. This action would be repeated until the fuel bed overlying the associated tuyre blocks imposed a greater resistance to the flow of air, and the weight of the dampers would be suincient to overcome the resulting change in differential pressure. In either case the air flow to the thin or porous portions of the fuel bed is throttled sufficiently to prevent blow holes or damage to the tuyre blocks. Thus when the air is so throttled the combustion rate will decrease, thereby enabling the fuel feeding elements to build up that portion of the fuel bed until it becomes normally uniform again. This change in fuel bed density creates a greater resistance to the flow of air which causes the pressure of the air in the associated passage I9 to' increase, thereby decreasing the differential in pressure acting on the associated damper elements, and as a result the damper elements will move downwardly toward open position to permit more air to flow through the associated tuyre. Referring to Fig. 2, the damper elements shown at A, B and C are in operated position, thereby shutting off the flow of air to the associated tuyre blocks. The arcuate portions 35 act as seals to prevent leakage of fluid past the dempers when the latter are in closed position. It therefore is apparent that the damper elements 3l and 32 associated with the tuyre blocks beneath the lighter portions of the fuel bed are operated automatically to close or partially close the passages IS thereof, while those associated with tuyre blocks beneath the heavier portions of the fuel bed will remain open to permit a greater quantity of air to flow therethrough, and as a result proper distribution of air to all portions of the fuel bed is assured for all conditions of operation.

Figs. 5 to '7 show a somewhat simplified embodiment of the present invention, wherein each tuyre block 42 has attached thereto a single damper element 43. In this construction each tuyre block 42 has provided at the front end thereof a substantially rectangular recess 44 in which is mounted the damper 43. As will be seen upon reference to Fig. 7, damper 43 occupies substantially the entire recess 44, and is of box-like construction having substantially flat top and bottom surfaces 45 and 46 respectively terminating at the rear ends thereof in a vertically disposed arcuate portion 47 which abuts or is slightly spaced from the rear wall 49 of recess 44. 'Ihe forward ends of top and bottom surfaces 45 and 46 terminate in a rounded portion 55 having projecting rearwardly from the opposite sides thereof a pair of apertured ears 5l and 52. A pair of forwardly extending projections 53 and 54 which form a portion of the side walls of recess 44 are each provided with a transverse aperture 55 which, when the damper 43.

is assembled on the tuyre block 42, align with the apertures provided in ears 5I and 52 respectively, and pin 55 insertedthrough these apertures pivotally supports the damper on said tuyre block. As shown more particularly in Figs. 5 and 6, the under side of each tuyre block 42 is provided with a depending projection 48 which partially closes the inlet opening between adjacent tuyre blocks. This projection is provided simply for the purpose of reducing the travel of damper elements 43 and may be eliminated if desired. Fig. 5 shows the parts in normal position wherein it will be noted that each of the dampers 44 rests upon a pin 5l to limit the downward movement thereof. In this oonstruction each damper 43 forms with the under side of the next upper tuyre block of the series a passage 58 which communicates with the inlet passage i9 defined by adjacent tuyre blocks and ribs I8', and'accordingly the upper side thereof is exposed to the pressure of the air in said passage. The lower surface of damper 43 is at all times exposed to the pressure in the plenum chamber, and consequently when any flow exists through the tuyre block each damper will be subjected to a differential pressure. In this case also the dampers 43 may be so constructed that their dead weight is sufficient to maintain the same in open position for a predetermined differential pressure or each may have a weight W provided at the rear end thereof.

Thus, in the event the resistance to the flow of air` through the tuyre blocks sh-ould'decrease, thereby increasing the velocity cf the flow therethrough, the static pressure operating against the upper surface of the damper elements will be reduced. Inasmuch as the lo-wer surface of each of these dampers is subjected to plenum chamber pressure which remains constant for any given fuel burning rate and which is always greater than the static pressure acting against the upper surface of the damper, each of the dampers is subjected to a differential pressure. When this differential pressure is suicient to overcome the weight of the dempers, the latter will move upwardly into engagement with the projections 48, as shown in Fig. 6, thereby cutting off the ow of air through the associated tuyre blocks, and as a result the air supply to the portions of the fuel bed above such tuyre blocks will be reduced. The fuel feeding mechanism may then build up such thin spots before any' damage occurs to the underlying Stoker parts. In this construction also a slight leakage occurs past the dampers when in closed position, and consequently they are subjected to a differential pressure of sufficient intensity to retain them in closed position.

A still further modification of the present invention is shown in Figs. 8 and 9. In this construction a pair of damper elements 'I6 and 11 are provided for each tuyre block 18. By this arrangement a somewhat better distribution of the air may be obtained inasmuch as it sometimes occurs that the density of the fuel bed over one side of a tuyre block is greater than that over the other, and when such a condition occurs damper element l5 or 'll may move to closed position, while the other remains open. Damper elements 'IS and 'El operate in the substantially rectangular recesses "I9 and 8i] respectively, provided at the front end of the tuyre block. These dampers each comprises a substantially fiat portion 8l which terminates in a vertically disposed arcuate portion 82 which engages or is slightly spaced from the rear wall 83 of the recess 19 or 80. Each of these dampers also has provided at the front end thereof a pair of apertured ears 815, the apertures therein in assembly align with apertures S5 provided in the forwardly extending projections 86, 81 and 8B respectively, of tuyre block "i8, and a pin 89 extending through these apertures pivotally supports the dampers in position. The operation of dampers 15 and ll is similar to that o-f dampers 43 and $2 previously described.

In all of the embodiments of the invention herein described, it will be observed that the dampers are disposed substantially longitudinally in respect to the direction of air flow to the tuyre blocks. Thus, the impact head of the air flowing past the dampers has little or no effect on the operation thereof.

The various novel forms of air control devices hereinbefore described obviously are not only simple in construction, but are highly eicient in operation. The control dampers may be readily assembled on the tuyre blocks, and when assembled require no field adjustments or periodic attention by the operator of the stokers. Moreover, by employing the present invention the maintenance cost of the stoker is materially reduced inasmuch as an independent damper is ,provided for controlling the draft air passing f through each tuyre block which operates automatically as soon as the fuel bed resistance decreases to a dangerous extent to shut ofi' the air supply thereto, and thus immediately reduce the combustion rate at that point. The fuel feeding elements may then feed additional fuel to that portion of the fuel bed before the incandescent fuel has had the opportunity to cause any serious damage to the tuyre blocks. Blow holes which often occur in furnaces, especially in those employing forced draft, are practically eliminated by the use of the present invention.

Applicants have also provided control units which may be readily applied to stokers now in the field, as well as to new installations, without necessitating any changes to the structure thereof.

While the embodiments herein shown and described are admirably adapted to fulfill the objects primarily stated, it is to be understood that it is not intended to limit the invention to these embodiments since it may be embodied in other forms, all coming within the scope of claims which follow.

What is claimed is:

1. In a device of the class described, the combination of a tuyre block` comprising a substantially flat body portion, a pair of spaced ribs depending from the under side of said body portion defining an inlet passage for draft air, a series of spaced ribs disposed between said iirst mentioned ribs subdividing said passage into a series of smaller passages, and a pair of interconnected damper elements pivotally supported on said first mentioned ribs.

2. In a device of the class described, the combination with a series including tuyre blocks, of means disposed between said tuyre blocks defining passages for draft air, of a source of air supply communicating with said passages, an upper and a lower damper element pivotally mounted on each of said tuyre blocks adjacent the inlet to the associated of said passages, said damper elements being so disposed that when the static pressure in one passage falls below that in the next lower passage, the upper of said damper elements of one tuyre block will move into engagement with the lower damper element of the next adjacent tuyre block, thereby throttling the ow of air through the associated passage.

3. In a device of the class described, the combination of a tuyre block, comprising a substantially flat body portion, said body portion having an open substantially rectangular recess extending rearwardly from the front edge thereof, a damper mounted in said recess, said damper comprising substantially flat spaced upper and lower surfaces and a substantially arcuate end portion, said end portion being in substantial engagement with the rear wall of said recess, and means for pivotally supporting said damper on said tuyre block.

ii. In a device of the class described, the combination of a tuyre block, comprising a substantially iiat body portion, a pair of spaced ribs depending from the under side of said body portion defining an inlet passage for draft air, said body portion having an open substantially rectangular recess provided at the front end thereof and disposed between said ribs, a damper mounted in said recess and adapted to close said passage, and means for pivotally connecting said damper to said ribs.

5. In a device of the class described, the combination of a series of tuyre blocks, a pair of spaced ribs provided on each tuyre block defining with the adjacent tuyre block a passage for draft air, each of said tuyre blocks having an open substantially rectangular recess provided at the front end thereof, a damper mounted in each of said recesses and adapted to close said passages, means for pivotally connecting said dampers to said ribs, each of said dampers comprising a substantially fiat portion extending longitudinally of said tuyre block and an end portion disposed at substantially right angles to said fiat portion and adapted in assembly to lie in substantial engagement with the rear wall of said recess.

6. In a device of the class described, the combination of a tuyre block comprising, a body portion, means provided on said body portion defining passages for draft air, each of said passages being restricted at the inlet end thereof, and diverging toward its discharge end whereby the velocity of the air at the discharge end is relatively low, and automatic damper means mounted adjacent said tuyre block tending to close the inlet to said passages when the velocity of the air passing therethrough exceeds a predetermined value.

7. In a device of the class described, the combination of a tuyre block, means provided on said tuyre block defining one or more passages for draft air, an automatically operable damper mounted adjacent each of said passages, each of said dampers comprising a relatively flat portion extending substantially longitudinally in respect to the direction of air flow to said passages, and an arcuate sealing portion disposed at an angle to said fiat portion, and means for pivotally supporting said dampers.

8. In a device of the class described, the combination of a tuyre block, means provided on said tuyre block defining one or more inlet passages for draft air, a source of air supply, a damper mounted adjacent each of said passages for controlling the flow of air thereto from said source of supply, each of said dampers comprising a relatively at portion, one side of which being subjected to the pressure of the air in its associated passage and the other side thereof being subjected to the pressure at said source of supply, whereby when said differential pressure exceeds a predetermined value said damper is actuated thereby toward closed position, and sealing means provided on said dampers for preventing air leakage from said source of supply to said passages.

9. In a device of the class described, the combination of a series of tuyre blocks, means disposed between said tuyre blocks defining passages for draft air, a source of air supply, a damper mounted adjacent each of said passages for controlling the ow of air thereto from said source of supply, each of said dampers comprising a relatively flat portion, one side of which being subjected to the pressure of the air in its associated passage, and the other side thereof being subjected to the pressure at said source of supply, whereby when said dierential pressure exceeds a predetermined value said dampers are actuated thereby toward closed position, and sealing means provided on said dampers for preventing air leakage from said source of supply to said passages.

l0. In a device of the class described, the combination of a series of tuyre blocks, means disposed between said tuyre blocks defining passages for draft air, a source of air supply, a damper pivotally mounted on each of said tuyre blocks adjacent each of said passages for controlling the flow of air thereto from said source of supply, each of said dampers comprising a relatively fiat portion, one side of which being subjected to the pressure of the air in its associated passage, and the other side thereof being subjected to the pressure at said source of supply, whereby when said differential pressure exceeds a predetermined value said dampers are actuated thereby toward closed position, and sealing means provided on said dampers for preventing air leakage from said source of supply to said passages.

1l. In a device of the class described, the cornbination with a series of tuyre blocks, including means disposed between said tuyre blocks defining passages for draft air, of a source of air supply communicating with said passages, and a damper unit mounted on each of said tuyre blocks, each of said damper units comprising a pair of interconnected damper elements, one of the elements of each of said units lying adjacent the inlet passage to one of said tuyre blocks, while the other of said elements lying adjacent the inlet passage of an adjacent tuyre block, whereby each of said damper units is subjected to a differential pressure, and one of the elements of each of said units being adapted to automatically move into engagement with the other of the elements of an adjacent unit when the differential pressure to which said unit is subjected exceeds a predetermined value to thereby throttle the flow of air to the said passage or passages of lesser pressure.

12. In a device of the classdescribed, the combination of a tuyre block, means provided on said tuyre block defining an inlet passage for draft air, a source of air supply, and an automatically operable damper mounted adjacent said passage for controlling the flow of air there-- in, said damper being disposed substantially longitudinally in respect to the direction of air flow in said passage and being so arranged that one side thereof is subjected to the pressure of the air in said passages, and its other side to the pressure of the air at said source of supply, whereby when said differential pressure exceeds a predetermined value said damper moves to closed position.

13. In a device of the class described, the combination of a tuyre block, means provided on said tuyre block dening an inlet passage for draft air, a source of air supply, and an automatically operable damper pivotally mounted on said tuyre block for controlling the flow of air in said passage, said damper being disposed substantially longitudinally in respect tothe direction of air flow in said passage and being so arranged that one side thereof is subjected to the pressure of the air in said passage, and its other side to the pressure of the air at said source of supply, whereby when said differential pressure exceeds a predetermined value said damper moves to closed position.

14. In a device of the class described, the combination of a plurality of tuyre blocks, means provided between said tuyre blocks defining inlet passages for draft air, a source of air supply, and a plurality of automatically operable dampers, one damper being mounted adjacent each of said passages for controlling the flow of air thereto, said dampers being disposed substantially longitudinally in respect to the direction of air flow in said passages, and being so arranged that one side of each is subjected to the pressure of the air in its passage and the other side tothe pressure of the air at said source of supply, whereby when said differential pressures exceed a predetermined value said dampers move to closed position.

15. In a device of the class described, the combination of a plurality of tuyre blocks, means provided between said tuyre blocks defining inlet passages for draft air, a source of air supply, and a plurality of automatically operable dampers, one damper being pivotally mounted on each of said tuyre blocks, for controlling the flow of air in the passage associated therewith, said dampers being disposed substantially longitudinally in respect to the direction of air flow in said passages, and being so arranged that one side of each is subjected to the pressure of the air in its passage and the other side to the pressure of the air at said source of supply, whereby when said differential pressures exceed a predetermined value said dampers move to closed position.

WILLIAM V. SAUTER. HOWARD F. LAWRENCE.

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