US2933208A

US2933208A - Pulp manufacture

Info

Publication number: US2933208A
Application number: US703590A
Authority: US
Inventors: Frank B K Green
Original assignee: Spront Waldron & Co Inc
Current assignee: Spront Waldron & Co Inc; Spront Waldron & Company Inc
Priority date: 1957-12-18
Filing date: 1957-12-18
Publication date: 1960-04-19
Anticipated expiration: 1977-04-19

Description

April 19, 1960 Filed Dec. 18, 1957 F. B. K. GREEN PULP MANUFACTURE 4 Sheets-Sheet 2 INVENTOR Frank B. K. ween,

ATTORNE April 19, 1960 F. B. K. GREEN 2,933,208

PULP MANUFACTURE Filed Dec; 18, 1957 4 Sheets-Sheet 5 E lNvEN-ro Fran/z .B.K. reen ATTORNEY April 19, 1960 F. B. K. GREEN 2,933,208

PULP MANUFACTURE Filed Dec. 18, 1957 4 Sheets-Sheet 4 I 9 I III Z 4 INVENTOR.

Fran/E 5.11: 911211 ATTORNEY United States Patent PULP MANUFACTURE Frank B. K. Green, Massapequa, N.Y., assignor to Sprout, Waldron dz Company, Inc., Muncy, Pin, a corporation of Pennsylvania Application December 18, 1957, Serial No. 703,590

6 Claims. (Cl. 214-17) This invention relates to the manufacture of pulp from wood or other fibrous material for making paper and the like and, more particularly, to rotary valve apparatus for introducing the wood or other fibrous material into cook ing or digesting apparatus where it is subjected to cooking or digesting or softening treatment at elevated temperatures and pressures.

As a result of technological and economic developments and considerations in the manufacture of paper, paper board, and the like, from Wood pulp or pulp of other fibrous materials, most of the operations in a pulp and paper mill other than the pulp cooking and digesting steps are carried on in a continuous fashion instead of in a batch-type manner. It may also be desired, however, that the initial cooking and digesting steps wherein the ligneous and other non-cellulosic encrustants or binding materials in Wood are softened or removed to render the WOOd fibres desirably separable for preparation of a pulp slurry also be carried out in a continuous manner for integration with the other continuous processes in the mill.

With continuous cooking or di esting apparatus through which the wood or other fibrous raw material is being continuously fed to be subjected to the cooking or digesting or softening action at elevated temperature and pressures and/or cooking or digesting chemicals, means are necessary for continuously introducing the chips of wood or other material into the cooking or digesting vessel and against high pressure therein without relief or escape of pressure from the cooking or digesting vessel.

According to this invention, rotary valve means are provided for the foregoing purposes to introduce and meter continuously chips of wood or other fibrous material into the inlet of cooking or digesting apparatus, and means are also provided for minimizing the escape or relief of pressure from such apparatus and for equlizing within the rotary valve itself the substantial pressure differentials upstream and downstream of the valve.

One object of this invention is to provide rotary valve apparatus of the character described adapted for positively introducing and metering chips of wood continuously into a cooking or digesting vessel maintained at a substantial super-atmospheric pressure while minimizing the escape of pressure therefrom.

Another object of this invention is to provide rotary valve apparatus of the character described, including provisions for equalizing pressures across the valve to lessen the loads and stresses imposed-on the bearings thereof by a substantial pressure differential upstream and downstream of the valve.

2,933,208 Patented Apr. 19, 1960 A further object of this invention is to provide rotary valve apparatus of the character described for continuously feeding and metering chips of wood or other fibrous material into a super-atmospheric pressure vessel, and including means adapted to seal the valve for minimizing escape of pressure thereacross.

Still another object of this invention is to provide, in rotary valve apparatus of the character described, means for receiving and positively feeding chips of wood or other fibrous material into a super-atmospheric pressure vessel, and including means for preventing jamming of the valve by oversized or misaligned chips.

Other objects and advantages of this invention will be apparent from the following description, the accompanying drawing, and the appended claims.

In the drawings- Fig. l is a side view of apparatus embodying and for practicing this invention;

Fig. 2 is an end view from the left end of the view of Fig. 1;

Fig. 3 is a vertical axial section on the line 3-3 of Fig. 2;

Fig. 4 is a vertical transverse section on the line 4-4 of Fig. 3; d

Fig. 5 is a partial vertical transverse section on the line 5--5 of Fig. 3; V

Fig. 6 is a veiw similar to Fig. 2 with some parts broken away; and

Figs. 7 and 8 are partial sections on an enlarged scale along the lines 7'/' and 8-8, respectively, of Fig. 5.

Although rotary valve apparatus embodying and for practicing this invention may be satisfactorily utilized in a variety of different systems or processes or apparatus for cooking or digesting wood or other fibrous material in the production of pulp for the manufacture of paper, paper board and the like, the preferred embodiment here illustrated is particularly adapted for use in a continuous pulping system as disclosed in my copending application Serial No. 703,622, executed and filed on even dates herewith, and/or in connection with continuous cooking or digesting apparatus as disclosed in my copending application Serial No. 703,5 88, executed and filed on even dates herewith.

Referring to the drawings, in which like reference numerals designate like parts throughout the several views thereof, a preferred rotary valve construction embodying and for practicing this invention is illustrated as comprising a generally cylindrical outer casing in which is a rotor 91 having a plurality of radially extending blades 92 mounted for rotation on a shaft 93 rotatably driven by drive means comprising a motor (not shown) and reduction gear drive 96. At the top of casing 90 is a chip inlet in flow communication with a supply of wood chips or other fibrous material (not shown), which may be from a conventional pulp mill chip storage bin or other apparatus or equipment pro-positioned to the rotary valve in the line of flow for preliminarily processing the chips or other material prior to reaching the rotary valve, and at the bottom of casing 90 is a chip outlet 101 in flow communication with the chip inlet of apparatus, such as a cooking or digesting vessel, into which chips or other material are to be fed and metered by the rotary valve.

Eachpair of adjacent blades 92 defines therebetween ae aae 3 a pocket for receiving chips entering through chip inlet 100 and for carrying the chips arouiid to di'op them out of chip outlet 101 as rotor 92 is rotated clockwise in the direction indicated by the arrows in Figs. 4 and by drive means, 96.

The radially outer edges of blades 92 are preferably provided with removable wear plates 98 affixed thereto as by bolts 99 and just clear the inner cylindrical surface lining 97 of casing 90 so that, during rotating of the bladed rotor 91, as each pocket between two adjacent blades 92 comes into flow communication with chip inlet chips drop thereinto and cooperate with wear 9. an t e inn ur ace l ni o easi 9t a s a ai e pe 9 p essu ee es the al e i em b el v ted Pre ure n the eee in .er isessi e essel flew et in nie tien t the .e i p ou e .10 as each Pocketful of ehipS is eerriet a ound-and d essed th h h Out 0 n h isa e er ethe app fit9 g a r e bla ed Me .1, i ie nales in s le bearin s 14 w h Pres ure resis an eekia in ,or afiixed to end closures 111 of casing 90. These closures .111 are provided with substantially fiat trans- 7 Valve and to lessen the bearing load on shaft 93 produced by the substantial pressure difierence above and below the rotary valve, a system of pressure bypasses, vents, and equalizers is preferably provided as indicated in Figs. 6-8- Th ss e ui n e enneet a poi inside casing 90 at approximately the 8 oclock position in Fig. 6 with another point at substantially the 4 oclock position. A further bypass conduit 10.5 connects a Pa n 99 t e nt e f asin 0 a t e 9 el position with a substantially diametrically opposite point at the 3 oclock position.

AS w l e se n f om the f ese ns a po k b een two adjacent rotor blades 92 at the 6 ocloclg position of Fig. 6 drops its load of chips through chip outlet 191 and, accordingly, the steam pressure in that pocket is then the high pressure of the digester or other apparatus into which'the rotary valve is feeding chips. With 'con tinued rotation of rotor 91, that same now empty pocket passes and comes into how communication with the 8 eeleels end f bypass Simultane usly enett e neeket h s ebe e e d esser! r ust ehip' e t 10. s i flew e gt tt ni at t w th h 4. e le k posi n o b ass 0,5 nd the h h eam p ess r n. the 8 eele k Peeke 1 ut me ee lv led ef an ua ized hrou h bypass 105 with the lower pressure in the 4 oclock neelse s ha h e ur d f er nt ween p outlet 101 and the 4 ocloclg pocket is reduced before the 4 oclock pocket reaches the 6 oclock position and the opposite pressure differential between the 8 oclock pocket and chip inlet 100 is simultaneously reduced. In the same manner as the 8 oclock pocket reaches the 9 oclock position in Fig. 6, still a different pocket loaded with chips is then in communication with the 3} oclock end of bypass 106, and a further pressure equalization is obtained through bypass 106. with a further reduction in pressure differential between the 9 oclock pocket and chip inlet 100.

A vent conduit 107 is preferably provided at the 10 o'clocl; position in Fig. 6, and a further vent or pressure equalizing conduit 108 is provided at the 2 oclock position. With these two conduits communicating directly with the atmosphere or with the interior of whatever 7 equipment or apparatus immediately precedes the rotary valve in the system or with a controllable source of steam or pressure, further pressure equalization or ad- J sttsen 18 a h e ed be en n emp y peeketressing 4 the 0 peleek pes en en i y to ride p a d of chips from inlet or in a just filled pocket passing the 2 oclock position on its way down to drop its chips through chip outlet 191.

Suitable connections for the aforementioned bypass and pressure equalizing conduits are indicated generally in Figs. 7 and 8 as comprising conventional pipe connections penetrating the closures 111 of casing 9i) and in flow communication with passages 112 leading to the interior casing 96 where they communicate sequentially with pockets between adjacent rotor blades 92 as such pockets coincide with the inner open ends of passages 112.

The axial extremities of rotor 91 preferably have a transverse configuration as indicated in Fig. 5 with an annular flange 116 having radiglly outwardly extending lips 117 at each end of each blade 92. Lips 117 preferbi e e s a n ca d n F s- 5 h he idth or circumferential" extent being slightly in excess of the diameter of passages 112 so that, during rotation of rotor 91, each of the passages 1-12 is momentarily closed by'lips 117 as the blades 92 pass across the open ends of passages 112 to prevent the passages 112 from being a in flow communication with two adjacent pockets at the same time. Furthermore, the axially outer radially outer portions of lips 117 are preferably formed with a cutout portion 118 providing a channel for initial pressure flow from the rotor pocket toor from an adjacent passage 1 12 around the edge of lip 117 to minimize any tendency for a sudden pressure surge from one'of the pockets out through one of the passages 112 to entrain or carry 7 along any of the chips or fibrous material in that pocket to plug or otherwise interfere with free pressure flow from the pocket into passages 112.

The inside of chip inlet 10% is preferably provided, as indicated in Fig. 4, with means for facilitating the gravity feed of chips into a pocket to be tilled without jamming the rotary valve should one or more of the chips dropping thereinto in random orientation remain protruding radially outwardly of the circle defined between outer edges of blades 92 and the inner surface lining 9 7 of casing 90. Such means includes a slanting partitiou 270 on the upwardly moving side of the valve to direct chips dropping through inlet 1% properly for falling into a pocket in rotor 91 approaching coincidence with inlet 100. At the other side of inlet 10%) a slanting plate 271 is provided, also for directing the flow of chips, but the inner edge of plate 271 is disposed radially outwardly of the circle defined by the inner surface of lining 9.7 and is circumferentially spaced from the point where inner lining 97 of'casing' 9t) begins. A

breaker plate 273 is provided at the point where'the inner lining 97 of casing 90 begins, to act, along with the inner edge of plate 272, as breaking or aligning means to remove or re-align or break any chips which may protrude radially outwardly from the chips in the rotor pocket beyond the inner surface lining 97 of casing 90, as well as to cut otf flow of chips into each pocket before blade 92 reaches a point adjacent plate 273. Also, as indicated in Fig. 4, an inspection slot 275 is preferably provided in casing 96 with a removable closure276 for ready access into the interior of casing 90 without disassembly of the rotary valve structure.

While the methods and forms of apparatus herein de scribed constitute a preferred embodiment of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

l. A rotary valve for use in a continuous pulp digester system of the character, described and adapted to receive chips of wood from a source of said chips and deliver them into a digesting vessel at a substantially greater super-atmospheric pressure than said source, which comand radially extending blades on said shaft defining there between a plurality of chip receiving pockets, a substantially cylindrical housing for said shaft and said blades, a chip inlet in said housing through which chips from said source of chips are sequentially received by said pockets between said blades, a chip outlet substantially diametrically opposed to said chip inlet in said housing and through which chips are delivered from said pockets between said blades into said digesting vessel, and said pockets being subjected sequentially to the super-atmospheric pressure of said digesting vessel and said lesser pressure of said source of chips as said pockets rotate in operation, and conduit means interconnecting said pockets other than said pockets in flow communication with either said chip inlet or said chip out-let sequentially in pairs for equalizing the pressure in each of said interconnected pair of pockets, said conduit means communicating with said pockets through end walls of said cylindrical housing and said blades including at the axial ends thereof an annular wall portion annularly wider than said conduit means for interrupting flow between said conduit means and said pockets while said annular portion of said blade passes said conduit means during rotation of said shaft.

2. A rotary valve for use in a continuous pulp dlgester system of the character described and adapted to receive chips of wood from a source of said chips and deliver them into a digesting vessel at a substantially greater super-atmospheric pressure than said source, which comprises in combination a rotating shaft, a plurality of axially and radially extending blades on said shaft detfining therebetween a plurality of chip receiving pockets,

a substantially cylindrical housing for said shaft and said blades, a chip inlet in the upper portion of said housing through which chips from said source of chips are sequentially received by said pockets between said blades, a chip outlet substantially diametrically opposed to said chip inlet in said housing and through which chips are delivered from said pockets between said blades into said digesting vessel, and bleed-off conduit means for withdrawing sequentially from each said pocket at one angular position other than when said pocket is in flow communication with said chip inlet or said chip outlet of said valve super-atmospheric pressure therein, additional conduit means for interjecting sequentially into each said pocket at another angular position of said valve super-atmospheric pressure, both said conduit means communicating with said pockets through end walls of said cylindrical housing and the axial extremities of said blades having an annular dimension greater than said conduit means for interrupting flow between each said pocket and each said conduit means as each said blade passes said communication of said conduit means through said housing.

3. A rotary valve for use in a continuous pulp di gester system of the character described and adapted to receive chips of wood from a source of said chips and deliver them into a digesting vessel at a substantially greater super-atmospheric pressure than said source, which comprises in combination a rotating shaft, a plurality of axially and radially extending blades on said shaft defining therebetween a plurality of chip receiving pockets, a substantially cylindrical housing for said shaft and said blades, transverse walls on said housing limiting the axial extent of said blades, conduit means communicating sequentially with said pockets through said transverse walls forpassage of superatmospheric pressure, arcuate transverse partitions on said shaft at each end of said blades defining rotating end walls for said pockets between said blades, a chip inlet in the upper por tion of said housing through which chips from said source of chips are sequentially received by said pockets between said blades, and a chip outlet substantially diametrically opposed to said chip inlet in said housing and through which chips are delivered from said pockets between said blades into said digesting vessel, radially outer edges of said rotating end walls being relieved axially away from said transverse partitions adjacent each said blade providing a tortuous passage for said super-atmospheric pressure into said conduit means while preventing the passage thereinto of chips contained in said pockets.

4. A rotary valve adapted to receive chips of wood from a source of said chips and deliver them into a digesting vessel at a substantially greater super-atmospheric pressure than said source, which comprises in combination a substantially cylindrical housing, a rotating valve member in said housing having a plurality of axially and radially extending blades defining therebetween a plurality of chip receiving pockets, a chip inlet at one side of said housing through which chips from said source of chips are received by said pockets between said blades as said pockets pass sequentially by said inlet during rotation of said valve member, a chip outlet in said housing through which chips are delivered from said pocket between said blades into said digesting vessel, said blades extending into close sealing relationship with the inner surface of said cylindrical housing except in the areas thereof defined by said chip inlet and said chip outlet, and baffle means extending partially over said chip inlet for cutting off the flow of chips therethrough into the one of said pockets passing said inlet and before the leading edge of said pocket has established said sealing relationship with said inner surface of said housing adjacent said inlet.

5. A rotary valve for use in a continuous pulp digester system of the character described and adapted to receive chips of wood from a source of said chips and deliver them into a digesting vessel at a substantially greater super-atmospheric pressure than at said source, which comprises in combination a rotating shaft, a plurality of more than 8 axially and radially extending blades on said shaft defining therebetween a plurality of more than 7 chip receiving pockets, a chip inlet in the upper portion of said rotary valve through which chips from said source of chips are sequentially received by said pockets between said blades, a chip outlet substantially diametrically opposed to said chip inlet through which chips are delivered from said pockets into said digesting vessel, and conduit means for equalizing the pressure in a plurality of stages between a pair of said pockets as one pocket of said pair approaches said chip inlet and the other pocket of said pair approaches said chip outlet but at angular positions around said valve other than positions in which either pair of said pockets is in flow communication with said chip inlet or said chip outlet said conduit means communicating with said pockets axially thereof and the axial extremities of said blades including annular bafile means forming a tortuous passage for said communication between said conduit means and said pockets as said baffie means passes said conduit means.

6. In a rotary valve of the character described adapted to receive material in increments from a source thereof and to deliver'said material into a zone of substantially greater super-atmospheric pressure than said source while sealing against loss of said super-atmospheric pressure, the combination which comprises a rotating shaft carrying a plurality of axially and radially extending blades defining therebetween a plurality of material receiving pockets, an inlet in the upper portion of said rotary valve through which material from said source is incrementally and sequentially received into said pockets, an outlet in the lower portion of said rotary valve through which material in said pockets is sequentially delivered into said super-atmospheric pressure zone, a substantially cylindrical housing for said rotary valve, conduit means communicating through end walls of said housing sequentially with each of said pockets at a plurality of angular positions of said pockets during rotation of said shaft for equalizing pressure between pairs of ascending and descending pockets effecting increasing the pressure in a 7. descending pocket'cont'aining; said material while" decreasing the pressure in' an ascending pocket empty of material, and annular end-walls forsaid pockets between said blades having'an' annular dimension greater than that of said conduit meansin said end walls of said housing-for interrupting flow communication between said conduit means and" said pockets as saidannular end'wall passes said conduit means, a portion of said annular'en'dwall of said pockets being relieved away from said end wall of said housing forming a tortuous passage for communication of pressure flow between said'pocket and said conduit means While preventing the entraining' of material from said" passage into said? citinidllit means by" said; msui fiow: r V V 1 References Cited inthe=filei of this patent UNITED STATESPATENTS V 2,260,926 Wright. on; 28', 194-1 2585;472. Kennedy Feb.. 12', 1952 2,7743'491'. Messing" Dec. [8, 1956 2,858,212 Durant 00!.28', 1958 FOREIGN PATENTS;

862,400 Germany Jan. I2, 1953"