US2545886A - Openable closure for chambers under superatmospheric internal pressure and associated fluid pressure means for preventing the escape of fluids therefrom - Google Patents

Description

March 20, 1951 L. KOOISTRA 2,545,886

OPENABLE CLOSURE FOR CHAMBERS UNDER SUPERATMOSPHERIC INTERNAL PRESSURE AND ASSOCIATED FLUID PRESSURE MEANS FOR PREVENTING THE ESCAPE 0F FLUIDS THEREFROM Filed Sept. 21, 1945 2 Sheets-Sheet 1 I INVENTOR lamberzf ffooz'szfira Pig. 2 BY M,

ATTORNEY March 20, 1951 L. KOOISTRA 2,545,886

OPENABLE CLOSURE FOR CHAMBERS UNDER SUPERATMOSPHERIC INTERNAL PRESSURE AND ASSOCIATED FLUID PRESSURE MEANS FOR PREVENTING THE ESCAPE OF FLUIDS THEREFROM Filed Sept. 21, 1945 2 Sheets-Sheet 2 I l i E I i l h' J- g 3 lNVENTOR l amber X00156 ATT'ORNEY Patented Mar. 20; 1951 ere OPENABLE CLOSURE FOR CHAMBERS UNDER SUPERATMOSPHERIC INTERNAL PRESSURE AND ASSOCIATED FLUID PRESSURE MEANS FOR PREVENTING THE ESCAPE OF FLUIDS THEREFROM Lambert Kooistra, Akron, Ohio, assignor to The Babcock & Wilcox Company, Rockleigh, N. J., a corporation of New Jersey Application September 21, 1945, Serial No. 617,719

9 Claims.

The present invention relates in general to the construction and operation of closure members especially adapted for use with furnaces or other similar closed chambered structures operating under high internal gaseous pressures considerably above atmospheric and requiring access at intervals without necessitating a shut-down or causing interference with their prescribed functions. Structures suitable for the practice of my invention include boilers for example having a combustion chamber together with a communiin the gases are maintained at superatmospheric pressures and an opening is provided affording eating gas flow space wherein the gases of combustion are utilized mainly for the generation and heating of vapor. In other suitable structures the high pressure gases may be produced for various other purposes such as for utilization in processes or as ahot motivegaseous fluid for gas turbines.

In such installations the enclosing walls are often fluid cooled to provide protection from high furnace temperatures and further are preferably made gas-tight throughout to avoid the troublesome and dangerous condition resulting from the ejection of high temperature'gases and other products of combustion. When a wall opening is provided through which access may be had to the interior for cleaning or other purposes it is essential that the opening be fitted with closure means suitably constructed and arranged so as to maintain the continuity of the gas-tight wall construction. Further, since it is essential in many instances to gain access to the interior during normal furnace operation, it is highly desirable to arrange in some manner to adequately control or to actually prevent the discharge of hot products of combustion when the closure means is removed or shifted to expose the opening.

There is an indication in the prior art that attempts have been made to restrict the escape of combustion gases through afurnace wall opening, in some instances through the use of air or steam jets directed'either across the opening in the form of a'screen, or' into the opening toward the-interior of the furnace. However,-

the prior-art structures are inadequate for opposing the discharge of high pressure gases and moreover do not provide among other features the required interrelation between operation of the closure means and the initiation of jet action. to assure complete control of gas discharge underall conditions.

An object of my invention therefore is to pre vent the ejection of gases from a chamber where access to the interior of the chamber.

A related object of my invention is the provision of apparatus adapted to open and close a furnace wall port while preventing the ejection of high pressure gas through the port through.- out the opening and closing periods. Another object is the provision of a closure member movable relative to a furnace wall open-1 ing wherebythe escape of high pressure gas is prevented throughout substantially the entire range of closure member movement.

An additional object is to prevent the ejection of high pressure gas from a furnace wall opening by directing fluid toward the opening in a series of high velocity jets converging within a tapering passage of minimum flow area adjacent the opening.

An object is also to provide, in conjunction with a furnace operating under superatmospheric internal pressures and having an access opening in a fluid cooled wall thereof, means for preventing the ejection of hot products of combus tion through the opening comprising a series of high velocity fluid jets converging inwardly toward the opening within a tubular member secured to tubes lining the wall, the tubular member constituting a frame for a door adapted to close the opening. I

A further object is the provision "of apparatus associated with a furnace wall opening whereby at one period a fluid under pressure is utilized to prevent the ejection of furnace gases through the opening and at another period is utilized to look a cover in place over the opening. I Other objects include the provision of a closure member adapted to be moved into open and; closed positions relative to a furnace wall open-'1 ing and while the member is in the open position to prevent the ejection of high pressure gas from the furnace by a'series'ofhigh velocity ularity in the claims'annexed' to" and forming' a' part of this specification. For 'a'better understanding of the invention, its operating advantages and'specific objects attainedby' its use,

reference shouldibehad to the accompanying drawings and'descriptive matter in' which I have illustrated and described a preferred embodiment of my invention.

Of the drawings:-,

Fig. 1 is a side elevation, mainly in section, of the lower portion of a steam generating unit embodying my invention;

Figs. 2 and 3 are enlarged front and side elevations, respectively, of portions of the structure Fig. lwisla plan section taken-along line 4-4 of Fig. 3.

The steam generating unit illustrated in Figs. 1 and 2 is substantially the same as that disclosed in my copending joint application with H. J. Kerr et al., Serial No. 552, l20,' filed August 31, 1944, except for certain features peculiar-to the present invention as will 'appear hereinafter, the unit including a cyclone type of primary furnace 10 from which the products' of'combustion flow into a secondary furnace l2."- Thewalls'of both furnaces are lined with wall cooling tubes suitably arranged and connected so as to form circuits paralleling the circulatory system of the boiler, the walls being of improved construction enabling the unit to be maintained under relatively, high positivei internal piess'ures' throughoutyas iully disclosed in theaforesaid prior application. I- ri' J .t'. :1

The cyclone-- typeprimary furnace ID" is of horizontally elongated substantially circular cross section and preferably fired-*by a pri'm'ary burner lkarrangednoaxially ithereof in :the outer "end wall M, the burner being ofia suitable type for the kindzof iuel to' befired which for present purposes may be assumed .to be a crushed or granular -fue1, such :28 bituminous "or semi-bituminous coal; 1 1A stream "of primary 'air'and granular coalis delivered at aiarelatively'zel'iigh positive pressure through the involute curved primary air-coal'pipe -l which opens tangentially into a'lower side pcr= tion OfEbur-ner- 13, 'thefefieetive flow area of the pipe and thereby ithe' velocity of "the fuel-air stream being: controlled by-a manually operated control damper IS. The burner is constructed to impart a-iradia1.and' forward motionto the entering'coaleair'stream 'and'the whirling stream movestaxially'of the;prima'ry furnace in-a'helical path along and in conta'ct'ivith thecir'cular wall w ,A w

:circulan tertiaryair ch'amber I 8 'is arranged at the outer end of the burner 13 and a regulable supplyztiofrpreheated air is delivered thereto the entering secondary air stream at all times along th'e-primaryriurnace chamber wall.'-* Y1 =5 "In accordance .with th'e'previous disclosure, the primary air-fuel stream enters thefiurnace chamber inla;high velocityzstreamwhirling"in a clock- WiSEQdiIGClZiOIliWKh' anvinner cor e' of tertiary' 'air' whirling the. same direction? 1 -The s r fuel-ail mixture rapidly-ignites andthe burni'ng stream flows longitudinally of the furnace chamber "at "a high angular velocity in a film or layer following a-helical path along and inrclose contact with the furnace circumferential wall; The secondary air -4 enters at substantially the same velocity and direction and gradually merges with the burning stream of primary air and fuel, without disrupting the helical flow path of the latter or separat- 5 ing the primary air-fuel stream from the circumferential chamber Wall by a layer or" second- --ary -air. Combustion is: substantially completed in-the primaryf'urnacechamber and the resulting hot gases are discharged through the coaxially arranged rearwardly flaring outlet throat 25 which is formed with an angle of flare of approximately'ltiito its axis to provide minimnm pressure drop'the rethrough. -----According to one method of operation all of the cembu'stionair may be supplied at a high positive pressure, e. g. 40 in. 1-120, to the primary furnace chamber and a decreasing positive pressure maintained throughout the remainder of the unit Open-i-i-1gs are provided in the Walls of the unit, at various positions, through which operation of the'furnace may be observed and, if desired, a lance or other implement insertecl to dislodge 'sl-ag on 'o'thfer accum tio'r isj orf an oilburner or other device "ii isert ed to "initiate the combustion or fuel introduce oughpipe l5. if n e me ansforoneb'f su'cho'pen- 53. a d 1%. Wh re f sim ati'o a v se t efipnandi anc ne w ee t as .opemneizij be. I. e ..a iete with a side' wall 29 of secondaryifurnace 1 2, The" wan 2 s iricmdfsifa etal as m 2 gaff welded tb' t-h outer side :of wall-tubes" 2}) to pi vide with other walls of -similar 'constructio n 'a completely sealed furnace chamber permitting operatic 'li'ighpositive fu'i' ljooifs of the same 'ge'r'ieraf'type and f u' r'rmy be nstalled s aw i qvirc ed locations 3'66, 3w; etc, in walls of"the 1s e oondary furnace l2 and as indicated at 321g, t zban d 2p in a-wallofthe'primaryjfurnace I D.

"The complete door assembly' 25 1 comprises a tubular ir'a'r'ne' '3'4 terminating in a conical inner end portion-"ssfadiacnt -th op"ening 21 where it is secured as by -w'eld'i'iig to adjacent wall tubes 28; The-frame is-ofbircularinternal cross'section" throughout providing "a central passage '36 having its wall portion 'l adjacent the opening 21 or gradually reducing taper *tow ardthe o1oening";a1id its wall portion 38 remote from-the'open ing of cylindricalformation; the tapering portion 31 extendmgm substantially tangential relation to-" tu'bes adjoining the opening Z'I fand being joined'to the'cylindricalportion 38 by an intermediate conical shoulder portion 39 facing the 'The door frame fi l'is' surrounded by a manifold extending axially from the outer end of the frainato'aloation inwardly of tl'i'eshoulder 3 9." Holes 42 are drilled through the inner wall of the i'nainfold'a't the sli ou lde'iflfl for directing high velocity *5 et's of 'air' or other gaseous fluid "into'Qthe central passage 36 fthe air or ample being de-'- livered under ressuie'oreo' sfi'; to the'mani fold' dl' through-1a pipeline 53f havingfa plug valve=45 therein? ZIl' e' 'jet holes or ports 42 "are:

arranged' in" afcircul'ar' rowfpie'ferably ij at sub-1 outer hole 46 for each inner hole 42, one or more of the holes 42 could if necessary be cleaned from inside the passage 36.

The frame 34 is symmetrically extended along its horizontal diameter to provide two substantially semi-circular extension portions 48 and 49, as shown in Fig. 3, each portion being formed with a cavity 5| as shown in Fig. 4 providing a continuation of the manifold space 4 I. The open side of each cavity 5| is closed by a. plug 52 screwed into the front wall of the frame and its extension 48 or 49, the slot 52a facilitating assembly and removal. The plug 52- in extension 48 supports an axially movable hinge pin 53 about which the door plate 26a is pivoted, while the corresponding plug in extension 49 supports an axially movable catch pin 54.

Since the hinge pin 53 and catch pin 54 have similar mountings and are similarly actuated, a description limited substantially to the illustrated catch pin assembly will cover the essential features of both. Accordingly, and referring particularly to Fig. 4, the catch pin 54 extends outwardly from a manifold space 5| through a central hole 56 in plug 52, the pin having a slot 51 formed in one side thereof adjacent its outer end, the axial width of the slot being greater than the thickness of the door plate 26a at its circumferential edge 58. A disc 59 on the inner end of the catch pin 54 serves as a seat for a spring 6| having one end bearing against the disc and its opposite end against the inner face of the plug 52.

The spring 5| being under compression forces the catch pin 54 inwardly so as to cause the outer edge 62 of slot 51 to push against the outer face of the door adjacent one end of its diameter, while a similar spring 6| in extension 48 forces the hinge pin 53 inwardly so as to cause the cotter pin 63 through washer 64 to exert a corresponding force against the door adjacent the opposite end of its diameter. Thus with the door 26 in its closed position, as shown, and with a relatively low or zero fluid pressure within the manifold spaces 5|, the springs 6| serve to lock the 'door firmly against its seat at the outer end of frame 34.

When the odor is in its closed position, the window 55 is centered over the outer end of passage 36 enabling operation of the furnace to be observed through the opening21. In this position also, the hole 61 in the door is centered over the plug of valve 45 enabling a valve key or other tool to be inserted through the hole into engagement with the squared end 68 for manual control of valve operation.

When the door 26 is to be opened, the valve key is inserted through hole 61 and the valve turned on to admit high pressure air into the manifold 4|, the air blowing through the jet holes 42 at high velocity toward the furnace wall opening 21 to prevent the ejection or blow-back of furnace gases. At the same time, the air pressure within the manifold forces both the hinge pin 53 and catch pin 54 outward, in opposition to the action of springsfl, whereby the door cover 26a is released from its seat. The valve key is then removed allowing the door to drop open and at the same time block access to air valve 45. The hinge pin 53 and catch pin 54 may each be formed with an enlarged intermediate flange portion 69 acting as a stop against the inner face of plug 52 to limit outward pin movement, in which case the extent of movement represented by space 1| is preferably less than thewidth of slot 51 to prevent the inner edge 12 from binding against passage.

the inner face of the door plate 26a and possibly interfering with opening movement.

In closing the door the operations are reversed, first, the door plate 250. being swung into closed position over the door frame passage 36 bringing hole 51 again into alignment with the plug of air valve 45. The valve is then turned off shutting off the supply of compressed air to manifold 44, except for a small amount of cooling air that may be admitted, if desired, through a hole 13 in the plug of the valve. As a result of the ac companying drop in air pressure within the manifold, the springs 6| again force the hinge pin and latch pin inwardly to lock the door plate 26a in its closed seated position.

When a hole 13 is provided, the air admitted therethrough serves to prevent hot gases from entering the passage 35 behind the door plate 26a, thereby helping to keep the door cool, and supplementing the cooling effect on the entire door assembly resulting from the heat conducting engagement of the frame with the wall cooling conduits 28. Additionally, if any slight outward leakage should occur, the leakage will be of air rather than of hot furnace gases.

During the period that the door is open, the air blown from holes 42 is directed toward the furnace chamber in high velocity jets converging at a point 14 for example along the central axis of passage 36 in a zone of reduced flow area such as at or adjacent the restricted throat passage 21 formed between wall tubes 28, the optimum point of convergence being determined, by test if necessary, with a view to rendering the jets fully eifectivein overcoming, the high static pressure of a given furnace under predetermined operating conditions.

The improved form of closure means herein disclosed is thus not limited in application to a boiler furnace operating at a positive pressure of the order of 40 in. H2O, as indicated for the embodiment herein described, but may also be usefully applied to furnaces of various types operating at positive furnace pressures ranging upwardly to or p. s. i., wherein the problem of preventing the discharge. of high temperature furnace gases becomes increasingly difficult. Furthermore, apparatus in accordance with this invention provides certain safety features which are of particular importance with furnace pressures of the magnitude mentioned, for example, the door cannot be opened until after the air jets are in action and the required air pressure established within the manifold to release the door, and secondly, the air cannot be turned off until the door is fully closed, thereby assuring complete and effective jet action throughout the entire period that the wall opening is uncovered.

I claim:

1. Closure means for a furnace wall access opening comprising a frame having an interior passage adapted to register with said opening, a cover movable into open and closed positions relative to said passage, means for directing gaseous fluid into said passage toward said opening in a series of high velocity jets converging along the central axis of said passage, and means responsive to a decrease and an increase respec tively in the pressure of fluid forming said jets for locking and releasing said cover relative 'to said frame in the closed position relative to said 2. Ciosure means for a furnace wall access opening comprising a frame having an interior passage adapted to register with said opening;

a cover movable into 9pen and I closed positigns gaseous fluid intos d passage toward said opening' aiser ies of l velocity jets 'c onverging along the central axisof said passage, and means responsive to "a decrease in the pressure of fluid forming 'said jets for locking said" cover relative to i said frame ithe closed position relative to ie i i s a In combination with a wall structure having an opening thereinto a chamber operable under superatmospheric internal pressure, closure means for said opening comprising a door movable into openfandclosed positions relative to said opening; means for establishing a'fluid pressure zone adjacent the outer side of said opening for preventing the ej ection of gases from said chamber when said door is in the open position, and means for controlling the supply of fluid under pressure to said zone, said control through which said "control means is renderedaccessible for operation only when said door is in" the closed position.

4. In combination with a Wall structure having an opening therein to' a chamber operable under superatmospheric internal pressure, closure means for said opening comprising a door movable into open andclosed positions relative to said'opening, means for maintaining a high velocity'gaseous fluid flow through a zone adjacent s'a' idppening for preventing the ejection of gases from said chamber when said door is in the open position, means for controlling said gaseous fluid flow accessible for operation from a predetermined location when the door is closed, and means operable in response to movement of said door for rendering said control means inaccessible for operation from said location when the door is open.

5.Closure means for a furnace Wall opening comprising a frame having an interior passage adapted to register with said opening, a door for said opening at the outer end of said passage, a manifold arranged annularly of said frame and having its innerwall portion in common with an outer wall portion of said frame, means for supplying fluid under pressure to said manifold, said common Wall-portion being provided with ports for directing said fluid into said passage in high velocity streams, a pin at one side of said passage forming a pivot support for said door, a pin at the opposite side of said passage forming a catch for said door, each of said pins extending into said manifold and functioning as a plunger movable in response to variations in fluid pressure within said manifold, means applying an inwardly directed force to eachpin in opposition'to' the outwardly directed force resulting from exposure to said manifold fluid pressure, means associated with an outer end portion of each pin for clamping said door in closed position against said frame upon inward movement of said pins in response to a decrease in said manifold fluid pressure, and control meansfor varying said manifold fluid pressure.

6. Closure means for a furnace wall opening comprising a frame having an interior passage adapted to register with said opening, a door for said opening at the outer end of said passage, a manifold arranged annularly o fsaid frame and having its inner wall portion in common withan outer wallportion.ofsaid frame rneans for supplying fluidfundn'pre sine; to Ysa'idmanifold, said common 'vvall 'portio'ri bing' ports for directing said fluid intosaidpas age. in high velocity streams, .a hinge lsupport for said door at 'one side of said passagaf'a "catch 'f o ..said; door at the oppositesideofsaid passage, said catch being movable from a door-engaging position when the door is closed to a positionreleasing ing comprising a door at the outer end of said opening movable ,into open and closed positions, means for directing gaseous fluid under pressure into said opening toward the inner end thereof, means for controllingthepressure at which said fluid is directed into said opening, means operable in response to a decrease in said fluid pressure for locking said door in the closed position and in response to an increase in said fluid pressure for releasing said door for movement into an open position.

8. In combination with a wall structure having an opening therein to a chamber in which a superatmospheric pressure is maintained, closure means for said opening comprising a door at the outer end of said opening, means for directing gaseous fluid unde pressure into said opening and effecting therein a gaseous fluid flow creating an inward suction at said outer end, means for controlling the pressure under which S d gaseous fluid is directed into said opening, means operable in response to variations in said fluid pressure for locking said door in closed position upon a decrease in said fluid pressure and for releasing said door for movement into an open position upon an increase in said fluid pressure.

9. In combination with a wall structure having an opening therein to a chamber operable under superatmospheric internal pressure, closure means for said opening comprising a door movable into open and closed positions relative to said opening, fluid pressure means for preventing the ejection of gases from said chamber, means including a valve for controlling the operation of said fluid pressure means, and means responsive to movement of saiddoor for preventing operation of said valve except when said door is in the closed position.

LAMBERT KOOISTRA.

nsE-sRENoEs CITED The following references are of record in the file'of'this'patent:

UNITED s'rAT s PATENTS.

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