US2343034A

US2343034A - Apparatus for the recovery of byproducts of coking ovens

Info

Publication number: US2343034A
Application number: US371972A
Authority: US
Inventors: Fred A Weber
Original assignee: Individual
Current assignee: Individual
Priority date: 1940-12-27
Filing date: 1940-12-27
Publication date: 1944-02-29
Anticipated expiration: 1961-02-28

Description

Feb. 29,-1944. F. A, WEBER 2,343,034

APPARATUS FOR THE RECOVERY oF Bar-PRODUCTS oF coKING ovENs Filed Dec. 27. 1940 g M lgagwww 'y l?) lmefdo; WEBER,

Patented Feb. 29, 1944.

UNITED STATES PATENT. OFFICE- APPARATUS FOR THE RECOVERY F BY- PRODUCTS 0F COKING OVENS This invention relates generally to improved apparatus and method employed in the recovery of by-product gases in the operation of coke ovens.

It relates more particularly to a new and improved type of injector nozzle adaptedvfor use in the recovery of ley-product gases which are likely to form gummy tar-like or carbonaceous deposits on surfaces exposed to contact with such gases. More specifically it relates to an improved steam injector and method of using the same having means so arranged and constructed as to be capable of use and adjustment in such a manner as to render impossible the formation of gummy or carbonaceous deposition upon any surfaces nor--` mally forming a portion of the outlet passage or channel for the steam injector, even when such injector is left in position with the nomle in the path andvexposed to the byproduct gases, and even though the nozzle is not in active use.

Byreference to a condition referred to as not in active use. it is intended to mean the conditions -and time period under and during which no steam is passing through the outlet passage or duct of the injector nozzle even though the nozzle is still retained in its position in the wall of the standpipe or other conduit through which the lay-product gases pass. l On the other hand, if through accident or over sight or improper handling. there should be formed a -layer or deposit of gummy or carbonaceous deposit on the surfaces forming a part of the outlet passage or duct of the nozzle. and' thus tend to clog or obstruct -`such outlet passage in part or whole, the improved injector is. provided with self-cleaning means which may be employed for clearing any such obstructing deposits from the outlet passage without the necessity of delay or loss of time in the charging' 'of the coking ovens which would otherwise occur, if it were necessary to' remove the steam injector nozzle for purposes of clearing any objec` tionable deposits above referred to.

Reference has been made to the two conditions when the steam injector is in use, and when it is not in use. The importance and pertinency of these distinctions will` beapparent because in the use of the steam injector nozzle of the prior coking art and in the recovery of by-product gases, no particular problem was presented during the period ofactive use, that is; during-the period when steam was passing through the nozzle outlet passage, because by reason of the force and temperature of the steam during passagethrough the nozzle, it tended to keep the nozzle passage clear and prevent the formation of any gummy or carbonaceous obstructing deposits. either in part or whole, in such outlet passage.

The period in the coking cycle during which '5 the greater amount of volatile gases` are given of! and during which it is desirable to induce a draft by the steam injector nozzle t to carry of! the smoke and gases to the gas collecting main, isv

during the period of charging the coke ovens or immediately after, charging of the ovens.'l It is during this initial period that the steam injector nozzle finds its greatestv use. The use at this period to carry' oil.' raw, more volatlleby-product gases to the collecting main, avoids thedischarge 1,, of such gases and coal dust to the atmosphere and thus avoids atmospheric pollution. Further,

I during this initial period, the formation of the gummy--orv carbonaceous deposits is not so likely to occur as at a later period in the coking cycle,

when the less vvolatile and heavier gummy and more stable products, which are more likely Ato form the objectionable obstructing' deposits 'in the nozzle, require higher temperatures fand longer periods of heating to carry them over from u the coke ovens through the standpipe and into the gas collecting main. Such heavier and less volatile products are. however. likely to condense or congeal as gummy or tar-like deposits on the nozzle upon reduction of temperature, during re- '30 moval of the coke from the ovens.

There may be conditions under which gummy,

tar-like and carbonaceous deposits may accumulate upon the nozzle exposed to the gas and tend *u to obstruct the outlet opening in whole or in part,

even while the nozzle is in use and whilev steam is being ejected therefrom. There may be other periods when it is not necessary to use the nozzie, these latter conditions being'generally near the end of the coking cycle when there are gen- 4|, rally. nov large volumes of smoky or more volatile gaseous products, and at thel completion of the v coking period when the coke is removed from the ovens. The latter period is accompanied with reduction of temperature. In either event, it is desirable to be able to clear and clean the nozzle outlet of any obstructing substance.

In accordance with the present invention the self-cleaning feature of the invention is obtained by providing a construction operable from outside of the standpipe and also of the injector, to entirely close or seal the steam outlet passage at its tip end which is the portion which extends furthest within the standpipe passage. The sealing and closing of the tip end of the outlet pasn sage would of course be during a period of nonuse of the nozzle, but the nozzle itself would not be removed but would remain in its position usually, in the standpipes or valve-body connecting with the gas collecting main, so'that the portion of the nozzle exposed to the passage of the byproduct gases would still be subjected to the objectionable deposits from the gases passing to the gas collecting main. There is also provided in the device a closure or sealing member which moves axially within the outlet passage in contact with the walls thereof to produce a. plunger or wiping effect to cleanse the walls of the outlet passage and the aperture of` any adhering gummy carbonaceous or other sustances obstructing the same in part or in whole.

In locating prior art injector nozzles of the,

constantly open end type, such nozzles were usually disposed downwardly in a downwardly directed dow of gases. Such an arrangement was desirable, if not essential, in order to avoid the gravity effect in an upwardly disposed nozzle, of any congealed, condensed or gummy deposits,

from being carried backward and downwardA within the inner aperture or chamber of the nozzle, particularly at such times when not in active use and steam was not issuing from the nozzle.

Such periods of non-use would include periods in which a reduction of temperature would take place such, for example, as at the end of the coking cycle, when the coke is being removed from the ovens. yAny deposits congealed or condensed within the exposed outlet passage and aperture of the nozzle, or any liquid products which 'might have found their way within the inner chamber or passage of the nozzle, particularly if the noz' zle were in a position in which the open end pointed upward, would tend to clog and obstruct the nozzle outlet aperture and passage, in whole or part. It frequently has occurred when using nozzles of the prior art, that it was necessary to delay the charging of the ovens in the continuous coking process, until the clogged nozzle had been removed and cleansed and again replaced. Such delays and loss of time are avoided by the employment of my improved nozzle with the self-cleaning device, together with the means for forming a complete seal and closure for the outlet passage. An additional advantage made possible by the employment of my improved nozzle, is that it enables the nozzle to be disposed in an upward directed flow or. path of gases, with the open ended tip of the nozzle disposed in an upwardly inclined direction when in use, without the hazard or danger of gummy or liquid deposits flowing backward or downward by gravity effect, into the nozzle passages to clog the same during periods of non-use, because lof the facility with which the tip end of the nozzle may be sealed and closed against the entry of any such objectionable obstructing deposits. This self-cleaning and self-sealing feature of the steam injector nozzle as aifecting'its disposition and arangement. has a very close relation in its cooperation and functioning with other elements of the coking system conducting the by-product gases, particularly in the respect of enabling an induced draft to be effected by a more direct, convenient and eilicient arrangement and 'disposition of the standpipe, gas collecting main. and intermediate connecting valve-body member. The valve-body structures of the prior art, in which the steam injector has been mounted in a substantially vertical position Y with the open end of the nozzle directed downwardly and in a downwardly directed flow of gases, have been of a rather complicated` and involved structure and have included a reve sel! curved neck or elbow, so that the gases were required to follow a rather tortuous path including substantially three right-angle bends or turns, in the path from the vertical standpipe connected with the coke oven to the gas collecting main disposed horizontally and to one side of the standpipe. By providing an improved nozzle such as that with the self-cleaning' and tip-sealing features disclosed herein, in which the nozzle may be mounted with the open tip end directed upwardly and laterally, a direct connection may be made between the standpipe and the gas collecting main, by the employment of a valve-body of relativeV simple construction and which employs only one substantially right-angle turn.

- The nozzle may be mounted in the outer wall of the standpipe and may be mounted at such an angle at a point approximating one end of a horizontal radial line of the right-angle bend in the connecting valve-body member, so that a substantially direct line of flow is effected from the nozzle tip across the right-angle elbow, and into the gas collector main, without the necessity of having to traverse a reverse bend at the elbow as has been done in the prior art.

In the drawing, one selected embodiment is shown for purposes of illustration of the improved type of nozzle and of the method in which it may be employed in its relation with other elements used in the coking process. It is understood that various changes in detail features and arrangement of elements may be made without departing in essential respects from this invention.

Figure 1 is a vertical section showing the general arrangement of parts including the upper portion of the coking oven, a standpipe, a gas collecting main, and a connecting valve-body with a steam injector nozzle therein for inducing a draft to carry off the by-product gases from the coke oven to the gas collecting main.

Figure 2 is an enlarged section of the improved steam injector nozzle showing the self-cleaning and tip-sealing features.

Figure 3 is a transverse section taken on the line and looking in the direction of the arrow III-III of Figure `2.

Figure 4 is a fragment in section showing a lmodified form of the nozzle in which the stem is threaded in the nozzle.

In the drawing, a top fragment of a coke oven I is shown in section, such oven having the usual outlet passage 2 therefrom for carrying off the by-product gases and other products through a standpipe shown as including a refractory lining 3 and surrounding metallic pipe I, the lower portion of said standpipe being connected to the oven in a manner well-known in the art by a usual collar 5 and seal 0. The gases are conducted from the standpipe through a substantially right-angle passage formed by a valvebody Il and into a gas collecting main 1 which is shown supported in a horizontal position to one side of the standpipe upon suitable beam structure I and bracket or cradle l above the oven I.

The valve-body III which serves as a connecting conduit for conveying the gases from the standpipe 4 to the gas collecting main 1, is provided with a number of valves. One of said valves is shown as a flap type of valve Il which is hinged at one side and opens directly to the atmosphere and is disposed in the valve body in a substantially direct line above the standpipe 4 it in position.

a,s4s,oa4

guided for movement axiallyof the nozzle in a f so that if'there is any excess of pressure developed within the gas passages for any reason,

'such pressure might be' released by exhaust of the gases directly to the atmosphere. A second 1 butterfly type of valve I2 is shown in the valvebody, such valve being disposed at 'a point between the valve |I opening,to'the atmosphere, and the gas collecting main 1. The detailconstruction of these valves will not be elaborated upon at this point, because they are types of valves well known in the art.

In order to linduce a draft within the passag conducting the gases from the coke oven to the gas collecting main, a steam injector nozzle I3 is shown mounted in the outer wall of the valvebody I0. 'I'he tip end I1 of the nozzle I3 having the outlet aperture therein, is disposed in a dibearing bushing 28 shown threaded in one end of the nozzle.y A shoulder 21 on thefbushing serves as a stop Yto limit the movement` of the bushing 26 in thenozzle. Atthe outer-fend of the bushing, a` packing 28 is provide'dfandis retained in position by the cap 29 threaded on the bushing 26 `in a manner wellknown Ithe art. A handlek 30 is provided at the cute of the stem 22 for moving the stemZZaiciallyy of the nozzle. As'shown in Figure 2, this atifal movement would be oi.' a sliding character.` As

' shown in Figure 4, a` modified form is disclosed rection upwardly and laterally of the passage` from the standpipe, across the passage in the valve-body In m a substantially direct diametric or chordal path to the gas' collecting main 1. Such an arrangement and disposition of the nozzle enables the laterally directed jet of gas or steam to be directed across the diameter of the in which the stem 22 is provided with a threaded portion 35 which engages *a lcorrespondingly threaded portion in the bushing 26.

A means is provided vfor effectively forming a sealst the tip end I1 of thevnozzle in order to 'prevent the formation of any gummy, tar-like tion of a sealing film across the nozzle outlet standpipe so as to form a blanket-like barrier protecting the elbow from the scouring and other deleterious eil'ects of the coking gases.

The location of the steam injector nozzle I3 at the position indicated at the end of a substantially horizontal radius line of the valve-body which conducts the by-product gases from the standpipe 4 to the gas collecting-main 1 by a single right-angle turn or deflection, contributes tol an effective and efficient transmission of the gases. The location of the steam injector nozzle I 3 at such a point enables an effective suction or draft to be formed by substantially direct discharge of the by-product gases from the standpipe of the gas collecting main through a minimum distance. The reverse turn usually emor carbonaceous depositsE upon the walls 2| of the outlet passage of the nozzle I3, or the formaaperture 20, even though such lm may not actually nd its way as a deposit upon the inner walls 2| defining the outlet passage. For this purpose, there is provided a forward plunger portion 3| of the stem 22 which snugly fits within the `outlet passage and forms a wiping contact with the walls 2| thereof. The outlet aperture and the end plunger portion 3| of the stem 22 may be formed of varying shapes. The outlet aperture should be sealed only during periods in ployed inA valve-bodies where prior art types of nozzles are employed, is eliminated. In addition to the induced flow due to the velocity effect of the steam issuing from the injector nozzle creat-- ing dinerential pressure areas at the right-angle' turn, the substantially direct dischargel into the vgas collecting main 1 of substantially klarger varea than a section of the standpipe and the valvebody. is an additional factor which contributes to further expansion of the gases and creation of additional draft effect.

The nozzle construction, as shown in mure 2,

which the nozzle is not actually being used, this period of non-use being, as` heretofore defined, those periods during which no steam is being ejected from the nozzle, even though the nozzle the shoulder merges into the end plunger portion 3| by a gradual taper or bevel seat which engages a portion of corresponding shape in the end wall of the chamber I8. y In addition to servcomprises an elongated-tapered body portion I3 having a chamber I3 therein extending longitudinally ofthe nozzle portion and havingV an outlet passage or aperture 20 dened by the walls 2| at the tip end I1 of the nozzle. Steam is conducted to the nozzle chamber I8 through thel steam pipe I5 which is shown threaded in a laterally disposed aperture at the opposite end of the nozzle. The body portion of the nozzle-at its opposite end is shown as'an enlarged portion. 34 in order to facilitate handling of the nozzle in placing it in position in the valve-body III, or other conduit, orinremoving it therefrom. As shown, the nozzle I3 is retained in position in the valve-body IIIl and is ntted in an enlarged boss or flanged portion I4 byl a tight driving nt. If desired, the nozzle may be provided with a threaded portion to, engage a correspondingly ling as a cleansing means, such a sealing arrangement also serves as a valve function in cutting oil' the supply of steam or other liquid which is being ejected from the nozzle. Such a valve function may be utilized as one supplementary threaded portion of the vvalve-body for retaining A valve I8 may be provided in the steam pipej'lt for controlling the supply of steam to theinozzl'e.- The nozzle isalso provided wltha stem 'portion 22 which is supported and to the main valve control I6 disposed in the steam supply line I5 outside andindependent of the nozzle I3. One possible advantage in controlling the steam supply by the tip Asealing means is that on occasions it may be ldesirableto maintain the temperature of the body portio of the-nozzle at the temperature of the steam even though steam is not actually being ejected from the nozzle. prevent the formation of deposits upon the nozzle by congeaiing or condensing, which might be the case if the nozzle were of a lower temperature. Such an advantage could not be utilized, where the sole means of controlling the steam is from a separate valve, such as a control valve I6 in the steam line I5 -at some distance from the nozzle I3.

A means is also provided for limiting the axial movement .of the stem 22 in the opposite outward Such a feature may serve to A direction. For this purpose there is provided a second shoulder or stop portion 23 having at one side thereof a face portion which tapers or merges into the stern portion 22 and engages or seats within a correspondingly shaped portion in the end of the bushing 26. Preferably the diameter of the shoulder portion 23 is larger than the shoulder stop 24 adjacent the other end of the stem, oneadvantage of such a difference in the size of the respective shoulders being that the fluid ow or pressure acting against the face 23' of the shoulder 23 would serve as a means of retaining the stem at its outward limit of travel, without the necessity for other locking or holding means, in the event that the frictional engagement of the stem with its bearing bushing 26 or packing 28 were not suillcient for this purpose.

As shown in Figure 2, the laterally disposed steam inlet aperture i9 within the enlarged pori tion 34 of the nozzle body is at a point adjacent the location of the shoulder 23 upon the stem 22, the relative arrangement and positioning of the inlet aperture and the exposed tapering face 23' of the stop 23 being subjected directly to the ilow of steam as it issues from the steam pipe I5 into the enlarged chamber 32 at the outer end of the nozzle chamber I8. By varying the relative sizes of the two stops 24 and 23, the relative diameters of the nozzle chambers I8 and 32, respectively, in which they are positioned, and by also varying the axial extent of the enlarged chamber 32 relative the distance that the end of the plunger 3i is required to travel before entering the outlet aperture 20, so as to permit the enlarged shoulder 23 to move within the restricted chamber I8, a control element or means is utilized for varying the pressure or velocity of steam between the points of either all on" or all off. The nozzle as herein shown and described is employed in the method of coking coal and the recovery of by-product gases and other products. However, a nozzle of this character having a self-cleaning and sealing means and also a capability of varying the pressure and quantity of liquid ejected, may be of use in-the spraying of other liquids, such, for example, as tar, which has a tendency to deposit in the tip of the nozzle and ca rburize if subjected to heat, and to cause a change in the size of the nozzle opening which is generally of a very small diameter. The facility for self-cleaning of the nozzle, without requiring the removal or disassembly of the nozzle, in order to clean the outlet passages, is a feature of considerable advantage.

While one preferred form of apparatus and one particular relation and disposition of elements has been shown in the application to the coking process, and the recovery of by-products has been shownl and described herein, it is understood that details of certain parts and modified arrangements may be made within the knowledge Kof those familiar with the art, without departing from the spirit of the invention.

I claim:

1. In mechanism for injecting steam in the byproduct coke oven gases conveyed from the oven through a standpipe during the oven-charging 'period to a gas collecting main disposed to one side of and on substantially the same level as the upper end of said standpipe to induce a flow and formation of any such deposits on the walls' cluding a standpipe and a self-cleaning hand actuated steam injector nozzle mounted at the upper end of said standpipe in the'outer wall of the right angle elbow so as to discharge a jet of steam within said standpipe laterally and slightly upwardly thereof at and across the upper end thereof to form a protective and deilecting blanket, into and at the elbow, at which portion the path of the gases is abruptly deflected by the blanket-like jet laterally across the diameter thereof, and from the standpipe to the gas collecting main whereby differential pressure areas are formed at the elbow within the path of gas travel before the coke oven gases reach the elbow which induces passage of the by-product gases from the standpipe directly by a single right angled turn in to the gas collecting main without requiring or necessitating discharge of gaseous, smoky or ignited products to the atmosphere.

2. In a by-product coke oven manually actuated self-cleansing steam injector nozzle adapted to be employed in by-product gases likely to form hardened gum and carbonaceous deposits on surfaces oi the nozzle outlet passage exposed to the gases, said self-cleaning steam injector nozzle i including a hollow cylindrical body portion having a longitudinally extending chamber, a tapering nozzle portion at one end and a restricted cylinder-like outlet passage therein of uniform cross-section, an inlet passage leading to said chamber and a valve for said inlet, a longitudinally movable stem member mounted to slide longitudinally of said chamber, the extreme outer end of said stem being plunger-like and of uniform cross-section throughout its length extending to the end thereof and adapted to fit snugly within and have a wiping contact throughout the extent of the cylinder-like outlet passage for the full length thereof and for a distance extending to the extreme outer end of the cylinder-like outlet `passage and of the nozzle to clear the same of any accidentally accumulated deposit of gummy or carbonaceous matter and to prevent the entry of the outlet passage when the end of the nozzle is in the path of the by-product gases during suchperiods of coking when no steam is being ejected from the nozzle to exert a cleaning eileot whereby there is eliminated loss of time incident to the necessity of removing a wholly or partially clogged steam injector nozzle for purposes of cleaning or repair.

'3. In a by-product coke oven, in combination, an up standpipe,4 a. self-cleansing steam injector nozzle adapted to be employed in'by-product l gases likely to form hardened gum and carbonaceous deposits on surfaces of the nozzle outlet passage exposed to the gases in said standpipe,

' a hollow cylindrical body portion having a longitudinally extending chamber, a tapering nozzle portion at one end and a restricted cylinder-like outlet passage therein of uniform.crosssection, an inlet passage leading to said chamber at the other end and .extending laterally thereof a bearto said gas collecting main. said mechanism ining bushing removably secured in the chamber at the end adjacent the inlet, a longitudinally movable stem member guided in said bushing and actuatedfrom outside said nozzle, the extreme outer end of said stem being plunger-like and of uniform cross-section throughout its length extending to the end thereof and adapted to flt snugly within and have a wiping contact throughout the extent of the cylinder-like outlet passage for the full length thereof and for a distance extending to the-extreme outer end of the cylinderlike outlet passage and of the nozzle to clear the same of accidentally accumulated deposit of gummy or 'carbonaceous matter and 'whereby there. is eliminated delays in the functioning of the coking oven during a charging period and loss of time incident t the necessity of removing a wholly or partially clogged steam injector nozzle for purposes of cleaning or repair.

4. In mechanism for by-product gas recovery from coke oven operation including in combination a standpipe, a gas collecting main, and a single right angle elbow valve body, in the path of the gases conducted by said standpipe to said gas collecting main causing a change in direction of gas movement and a disposition to formation of turbulence and eddy currents at said elbow, including a ilat type of valve, opening directly to the atmosphere, means for inducing a ilowpf by-v product gases from said standpipe directly to said gas collecting main and in minimizing the tendency to form turbulence andeddy currents at the elbow, said means including a Vmanually vactuated self-cleaning steam nozzle, mounted in the outer wall of the standpipe adjacent the elbow to form a steam jet substantially horizontally and laterally of, and within and across the diameter of the vertical standpipe at the elbow, and before said gases reach the ilap type valve in the 4valve body, whereby the gases together with the steam and any condensed moisture are induced to flow directly into the gas collecting main by a single substantially right angle deflection from the upward direction of gas flow in the standpipe, and whereby the -laterally directed jetof steam forms a blanket-like protection of the elbow from the scouring and other deleterious action of the coke oven gases.

5. In mechanism for inducing circulation cf by-product gases from a .vertical standpipe to a gas collecting main in the operation of coking ovens, the combination including a verticalstandpipe, a steam injector nozzle mounted in the outer wall of said standpipe most distant from the gas collecting vmain and having the delivery end of said nozzle extending through said outer wall oi' said standpipe so as to be subjected to the byproduct gases said nozzle including an elongated body-and chamber therein, an outlet passage of uniform cross-section throughout its length' and terminating in the tip end of the nozzle exposed to said gases which are disposed to form gummy or carbonaceous deposits on surfaces exposedthereto and closure means including a plungerlike section of uniform cross-section adapted to t snugly, with a wiping contact within and throughout the extent of the outlet passage and movement therethrough for sealing the outlet passage when steam is not being ejected there` from to prevent the formation of any gummy or carbonaceous deposits within said outlet passage or on the walls thereof which would cause restriction thereof and interfere with the flow of steam therefrom.

6. In mechanism for inducing circulation-of by-product gases from the standpipe to the gas collecting main in the operation of coking ovens.

said mechanism including a standpipe, a steam injector nozzle adapted to be mounted in said standpipe and having the delivery end of said nozzle extending through the walls of said standpipe so as to be subjected to the by-product gases including an elongated body and chamber therein, an outlet passage of uniform. size and section throughout in the tip end. of. the nozzle exposed to said gases in the standpipe which are disposed to form gummy or carbonaceous depositson surfaces exposed thereto, and closure means for sealing the outlet passage, said closure means including a stem mounted for movement axially of stem in each direction, a steam inlet passage iaterally disposed at the outer end of the'lnozzle,

'the larger of said stops being disposed on the stem at a point adjacent said steam inlet whereby the ow of steam at the .inlet point is effective upon said larger disk-stop to hold the stem in an open position, with the disk-like stop in abutting rela- K tion with the stem bearing guide, the second disklike stop being spaced from the other end of the stem and adapted to limit the outward movement of the end of the stem through the outlet passage when clearing the same of any obstructingl material, the movement of the end of the stem outward being such as tomove the larger disk-like stop member through and past the incoming flow of steam in the inlet passage and to cause such steam flow to exert a pressure on the opposite side of the larger disk-like stop and to urge movement of said stem in the opposite direction.

'1. In mechanism for inducing circulation of byproduct gases from the standpipe to the gas collecting main, said mechanism including a standpipe, a steam injector nozzle adapted to be mounted in said standpipe and having the delivery end of said nozzle extending through the walls of said standpipe so as to be subjected to the by-product gases including an elongated body and chamber therein, an outlet passage of uniform cross section in the tip end of the nozzle exposed to said gases in the standpipe which are disposed to form gummy or carbonaceous deposits on surfaces exposed thereto, and closure -means for sealing the outlet passage, said closure means including a plunger-like stem of uniform cross section,corresponding to that of the outlet passage mounted for movement axially of the nozzle and adapted to fit snugly within the outletv the second disk-like stop being spaced from the other end of the stem and adapted to limit the outward movement ofthe end of the stem through the outlet passage when clearing the same of anyy FRED A. WEBER:

obstructing material.