US3130879A

US3130879A - Rotary feed valve

Info

Publication number: US3130879A
Application number: US52107A
Authority: US
Inventors: Hjalmar S Messing
Original assignee: Black Clawson Co
Current assignee: Black Clawson Co
Priority date: 1960-08-26
Filing date: 1960-08-26
Publication date: 1964-04-28
Anticipated expiration: 1981-04-28
Also published as: GB989347A; BE607553A

Description

April 28, 1964 H. s. MESSING 3,130,879

ROTARY FEED VALVE Filed Aug. 26, 1960 3 Sheets-Sheet l FIG 1 IO l2 l9 I8 INVEYINTOR.

HJALMAR S.MESSING ATTORNEYS April 28, 1964 H. s. MESSING 3,130,879

' ROTARY FEED VALVE Filed Aug. 26, 1960 s Sheets-Sheet 2 FIG-3 /4 INVENTOR HJALMAR S. MESSING ATTORNEYS April 28, 1964 H. s. MESSING 3,130,879

ROTARY FEED VALVE Filed Aug. 26, 1960 3 Sheets-Sheet 3 IN VEN TOR.

H JALMAR S. MESSING BY WM Mm ATTORNEYS United States Patent 3,130,879 RGTARY FEED VALVE Hjalmar S. Messing, New York, N.Y., assignor to The Black-Clawson Company, Hamilton, Ohio, a corporation of Ghio Filed Aug. 26, 196i Ser. No. 52,107 6 Claims. (Cl. 222-368) This invention relates to rotary valves and more particularly to feed valves for introducing chips or other fibrous material into cooking or digesting apparatus against an elevated pressure head.

Rotary valves which are employed to introduce pulp into a digester or the like customarily operate under high temperatures and superatmospheric pressures. Various arrangements and schemes have been employed in such rotary valves to provide rotor-to-body seals with a minimum of pressure loss under such conditions. These arrangements include porting and valving for partial pressure equalization across the rotor, and the expedient of increasing the cross sectional area of the rotor to resist bending by the differential pressure.

This invention recognizes that some bending or deflection of the rotor occurs under conditions of high pressure differential and provides an arrangement which compensates for deflection of the rotor trunnions due to such pressure as well as due to heat expansion and bearing slackness, thus assuring the maintenance of working clearances and an effective seal throughout the operation. Such adjustment is preferably effected through an angularly positionable rotor bearing housing which supports the rotor in eccentric relation to the body of the valve. The housing is angularly movable in increments into any one of a plurality of fixed positions to provide selection in the relative position of the offset.

The invention further provides a rotor constructed to have a high proportion of the material of the rotor radially outwardly distributed and including an arrangement of alternate deep and shallow buckets, with increased strength and carrying capacity. The body cavity includes a wear sleeve or liner which is reversible in the body to present new wearing and shearing surfaces to the outer edges of the rotor.

It is therefore an object of this invention to provide a rotary valve as outlined above providing compensation for the pressure loading by an angularly adjustable offset of the rotor with respect to the body.

A further object of this invention is to provide a rotary valve as outlined above including an eccentrically mounted rotor in a body and with the eccentricity of the rotor being positionable into a plurality of fixed angular positions for the adjustment of the position of the eccentricity relative to the valve inlet and outlet.

Another object of this invention is the provision of a rotary valve as outlined above having a bearing housing for receiving the rotor bearings in offset relation to the rotor cavity in the body, with this housing preferably being rotatably positionable within the body.

Another object of this invention is to provide a valve having a rotor with alternate shallow and deep buckets with a maximum utilization of the rotor material radially outwardly of the rotor center line, characterized by a high moment of inertia and carrying capacity.

A further object of this invention is to provide a rotary valve as outlined above characterized by versatility, long service life, and having a minimum of Wearing parts.

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

In the drawings:

FIG. 1 is a side elevation of a rotary valve constructed in accordance with this invention;

FIG. 2 is a transverse section through the valve taken generally along the line 2-2 of FIG. 1;

FIG. 3 is an enlarged section showing the details of the arrangement of one of the rotor trunnions within one of the end covers taken generally along the line 33 of FIG. 4;

FIG. 4 is an end view of the drive side of the valve; and

FIG. 5 is a side elevation of the rotor with a portion of one of the rotor buckets being broken away to the center line to show the internal details thereof.

Referring to the drawings, which illustrate a preferred embodiment of this invention, a valve 10 constructed according to this invention includes a casing or body 12 within which is formed a generally cylindrical cavity 13 (FIG. 2). The body 12 forms a flanged tubular intake opening or inlet 14 and a similarly flanged discharge opening or outlet 15 arranged diametrically opposite from the inlet 14. The inlet 14 and outlet 15 each are opened into the cavity 13.

A pair of heads or end covers 18 and 19 are mounted at the opposite sides of the body 12 in closing relation to the cavity 13 by means of a plurality of recessed machine screws 20, shown in FIGS. 3 and 4. The end covers 18 and 19 serve to retain a generally cylindrical sleeve-like liner 25 which is proportioned to fit within cavity 13. The liner 25 is formed with an inlet opening 26 and an outlet opening 27 arranged to lie respectively adjacent the body inlet 14 and outlet 15. The liner 25 further in cludes four longitudinally extending slots 28, two each of which are equally spaced in the liner 25 on either side of the body inlet and

outlet openings

14 and 15. The upper two slots 28 are aligned with grooves 30 and blow-off openings 31 formed in the body 12 and cooperate to discharge steam pressure from the valve 10. Only one blow-off opening 31 is used at one time, depending upon the direction of rotation of the valve 10, and the other opening 31 is suitably stopped as by a plug or permanent valving (not shown).

The remaining pair of slots 28 is employed to key the liner 25 against rotation within the cavity 13 by means of holding bolts 34 which are threaded into the body 12 and which have ends 35 proportioned to extend into the adjacent slots 23. The bolts 34 therefore serve to prevent the rotation of the liner 25 within the body 12.

The outer edges of the liner 25 abut the inside surfaces of the end covers 18 and 19, and are thus held against longitudinal movement in the body 12. The end covers 18 and 19 are each formed with an annular shelf or shoulder portion 36 (FIG. 3) which preferably forms an interference or press fit with the adjacent inside surface of the liner 25 providing rigidity to the valve and resistance to deformation due to internal pressures.

A rotor 40 is rotatably mounted in the body 12 at opposite journals or

trunnions

42 and 43 which are integrally formed therewith and which extend respectively through the end covers 18 and 19. The rotor 40 includes a generally centrally disposed bucket portion 45 received within the body 12 between the end covers, and is shown in FIGS. 2 and 5 as preferably integrally formed with the trunnions 41 and 42. The bucket portion 45 defines alternate deep buckets 47 and shallow buckets 48 therein. The bucket portion 45 consists of a spider 50 of material which defines the buckets and forms shearing and sealing edges 51 to the inside surface of the liner 25. The outer extremities of the spider 50 are arranged with relation to the adjacent surface of the liner 25 so as to present the shearing edges 51 regardless of the direction of rotation of the valve. Transverse openings 55 are formed in the bucket portion 45 and extend between each inside surface of the end covers providing passageways for pressure equalization.

The arrangement of the alternate deep and shallow buckets provides a spider 50 having a distribution of a substantial portion of the material of the rotor radially outwardly of its center to provide a high moment of inertia resisting bending by steam pressure at the outlet 15. The

buckets

47 and 48 are characterized by generally

cylindrical bottoms

53 and 54 joining straight sides. The radius of curvature of the bottom 54 of the shallow buckets 48 is preferably greater than the radius of curvature of the cylindrical bottoms 53 of the deeper buckets 47, thus permitting a deeper inward extension of the deeper buckets 47 toward each other and toward the center of the rotor, maintaining high capacity consistent with high rotor strength.

A pair of bucket purging openings 56 are formed in the body 12 adjacent opposite sides of the outlet 15 and cooperate with deflection plates 57 to direct a jet of steam under pressure into the interior of the adjacent bucket as it rotates into discharging position to purge the adjacent bucket of its contents. Only one of the purging openings is used at one time depending upon the direction of rotation of the valve, the other opening 56 being suitably plugged or connected to closed valving.

The escape of steam from the rotor cavity 13 into the end covers is prevented by packing rings 60 which are received within a recess formed between the

adjacent trunnions

42 and 43 and the end covers 18 and 19. A lantern ring 61 is positioned between adjacent packing rings providing lubrication thereto through a drilled opening 62, and the rings are held in sealing compression by a packing gland 65.

It is recognized that the steam pressure at the outlet 15 can cause some bending or deflection of the rotor within the body 12, and some deflection of the trunnions in their bearings. Generally speaking, the smallest possible steam loss with a given capacity is desired, with the additional benefit of good uninterrupted feeding. The peripheral clearance between the rotor and the stationary liner should preferably be as small as possible.

This invention provides a valve including adjustable means for effecting control of the operating clearances to compensate for the effects of deflection at the rotor trunnions due to steam pressure at the outlet, heat expansion, bearing slackness, wear, and other factors effecting the clearance between the shearing edges 51 of the rotor and the inside surface of the liner. Such adjustable means includes the bearing housings 70 within which the trunnion roller bearings 72 are mounted and which are formed with an annularly inwardly extending foot 73. The foot 73 engages a spacer 74 at the trunnion 42 and forms a grease-retaining seal for one side of the bearings 72.

The trunnion support bearings 72 are eccentrically mounted within bearing housings 70, as indicated in somewhat exaggerated manner for the purpose of illustration by the center line 76 for the rotor 40 as being offset toward the outlet 15 as compared to the center line 77 for the cavity 13. This offset is conveniently effected by grinding the bearing opening in the housing 79 eccentric to the center line of the outside of the housing 70. The amount of offset is determined by the loading and size of the valve and is determined as the amount which obviates the effects of the above numerated factors, and may be in the order of several thousandths of an inch.

Means for accurately positioning the eccentricity of the center line 76 of the rotor 40 with respect to the body 12 includes the housing 70 which is angularly movable in the end covers into a plurality of fixed positions. As shown in FIGS. 3 and 4, an end cover plate 8! is secured to the housing '70 by a plurality of recessed machine screws 81 and forms a bearing grease seal at the shaft by annular grooves 82 and a seal 83. The end plate 80 also serves as a means for angularly positioning the housing 70 in the end covers.

The

covers

18 and 19 may be provided with a plurality of screw openings 85 spaced at 15 intervals, as shown in FIG. 4. The end covers may also conveniently be provided with index means consisting of index markings 86 which designate the degree of rotation of the housing 79 from a given position, such as the position of maximum eccentricity toward the outlet opening 15. The index markings 86 therefore define the relative positions of the

center lines

76 and 77.

The housings 70 may therefore be rotated into any one of a plurality of fixed angular positions and secured by screws 88 through the cover 1% to provide adjustment of the point of least clearance between the rotor 44) and the liner 25, as desired. The adjustment provided by the eccentric mounting of the rotor bearings may be changed from time to time to compensate for rotor and/or liner wear to reduce and control steam blow-by at the inlet and provide longer service life. Also, the liner 25 is reversible through 180 to present new wearing and shearing surfaces for the rotor bucket shearing edges 51.

In operation, the valve 16 may be connected in the usual manner for feeding a digester or the like. Material to be fed by the valve is applied at the inlet 14 for delivery to the outlet 15 by either clockwise or counterclockwise rotation of the rotor 40, as desired. One of the purging openings 56 is connected for continuous operation to a source of steam under pressure to direct steam into the adjacent bucket as it rotates past the outlet opening 15 to assist in emptying the contents therefrom. The blow-off opening 31 located generally opposite the active purging opening 56 may be opened or suitably connected to permit the release of pressure trapped within the buckets as they rotate toward the inlet 14. The housings 70 may be positioned by the removal of the end plate screws 88 and by turning the end plate with reference to the index markings 86, as desired, to achieve the least amount of blow-by consistent with the maintenance of running clearances during operation.

The side walls of the rotor 40 preferably form a free space or running clearance with the adjacent surfaces of the end caps 18 and 19 between the liner 25 and the packing 69, as indicated at 90 in FIG. 3. When the valve 10 is used for handling cellulose material, such as wood chips, the space 90 becomes filled with fiber particles which solidify into a carbonaceous packing having the characteristics of a graphite bearing. This provides an effective seal at the ends of the rotor which retards the flow of steam from the outlet through the peripheral clearance at the liner and across the ends of the rotor and again at the periphery to find its way to the outlet and into the raw material.

If desired, the space 90 may initially be packed with resinous sawdust or similar material at assembly. This is particularly helpful in retarding leakage in the reassembly of a used valve where the liner and/or rotor may be Worn, and it is not desired to await the accumulation and hardening of a packing from the material being fed through the valve.

This invention therefore provides a rotary valve characterized by high capacity, long service life, and a minimum of pressure loss. The rotors spider, with the arrangement of alternate deep and shallow buckets, provides a high distribution of material radially outward of the rotor center with increased moments of inertia for a given ca pacity resulting in decreased deflection. The effects of the bending or deflection of the rotor is further controlled by the adjustment of the relative position of the offset of the rotor in relation to the body to provide minimum running clearances under the influence of pressures with minimum pressure loss. This results in continuous feeding which is uninterrupted by the effects of blow-by.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form 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:

1. A rotary valve for operating at high pressures comprising, a body including means defining a cylindrical cavity having a material inlet and outlet opening into said cavity, a rotor including a spider received in said cavity defining alternate deep and shallow buckets with the material of said rotor separating each said shallow bucket from the adjacent said deep buckets being radially outward of the material separating adjacent deep buckets, integrally formed oppositely extending trunnions on said spider, and means on said body rotatably mounting said trunnions in offset relation to said cavity to compensate for the bending of said rotor by pressure at said outlet.

2. A rotary valve for operating at high differential pressures comprising, a body including means defining a cylindrical cavity having a material inlet and outlet opening into said cavity, a rotor including a spider received in said cavity forming alternate deep and shallow pockets with the material of said rotor separating each said shallow bucket from the adjacent said deep bucket being radially outward of the material separating adjacent deep buckets, integrally formed oppositely extending trunnions on said spider, a pair of end covers on said body enclosing said cavity, bearing housings including bearings receiving said trunnions in eccentric relation to said cavity, said bearing housings being rotatively received in said covers for selectively and measurably ofisetting said spider to compensate for the bending of said rotor by pressure at said outlet.

3. A rotary valve designed to operate into a high pressure head with a minimum of blow-by, comprising a valve body, means in said body defining a cylindrical cavity, a rotor including a bucket portion received within said cavity having means defining alternate deep and shallow buckets with said deep buckets being formed with greater radial depths than said shallow buckets, trunnions at opposite ends of said bucket portion, a pair of end covers one each mounted on opposite sides of said body in closing relation to said cavity on either side of said bucket portion with said trunnions extending therein, bearing housings received in said end covers and angularly rotatable in predetermined fixed increments therein, said housings including trunnion supporting bearings eccentrically mounted therein and rotatably receiving said trunnions, and each of said bearings being movable with the rotation of said housing to position the eccentricity of said bearings with respect to the center line of said cavity to compensate for pressure loading of said valve.

4. A rotary valve comprising a valve body, means in said valve body defining a cylindrical cavity axially thereof, said body having an inlet opening into said cavity and a discharge outlet leading therefrom, a rotor rotatably received in said cavity and defining alternate deep and shallow buckets of differing radial depths arranged to receive material at said inlet and to discharge material at said outlet upon the rotation of said rotor, the material of said rotor being distributed between said buckets with a major portion thereof lying in the outer half of the rotor radius separating adjacent deep and shallow buckets to resist bending by pressure at said outlet and with a minor portion of said rotor material being distributed in the inner half of the rotor radius between adjacent deep buckets.

5. A rotary valve comprising a valve body, means in said valve body defining a cylindrical cavity axially thereof, said body having an inlet opening into said cavity and a discharge outlet leading therefrom, a rotor rotatably received in said cavity and including a spider defining alternate deep and shallow buckets of diflering radial depths arranged to receive material at said inlet and to discharge material at said outlet upon the rotation of said rotor, the material of said spider being distributed with a substantial portion thereof lying in the outer half of the rotor radius to resist bending by pressure at said outlet, said buckets having substantially cylindrical bottoms with the bottoms of said deep buckets having a smaller radius than the bottoms of said shallow buckets.

6. A rotor for a rotary valve for the delivery of material from the valve inlet to the valve outlet, comprising a rotor body having means defining alternate deep and shallow buckets of differing radial depths having common peripheral wall portions, said rotor body having three equally spaced deep buckets separated by three equally spaced shallow buckets, said shallow buckets having a radial depth of less than one-half the radius of said rotor, and said deep buckets extending to a depth greater than one-half of said rotor radius providing a distribution of a substantial portion of the material of said rotor between said deep and shallow buckets in said outer half of said rotor radius to resist bending by pressure loading on said rotor.

References Cited in the file of this patent UNITED STATES PATENTS 2,161,553 Westberg et a1. June 6, 1939 2,766,911 Greaves et al Oct. 16, 1956 FOREIGN PATENTS 42,629 Netherlands Feb. 15, 1938 443,134 Great Britain Feb. 21, 1936

Claims

5. A ROTARY VALVE COMPRISING A VALVE BODY, MEANS IN SAID VALVE BODY DEFINING A CYLINDRICAL CAVITY AXIALLY THEREOF, SAID BODY HAVING AN INLET OPENING INTO SAID CAVITY AND A DISCHARGE OUTLET LEADING THEREFROM, A ROTOR ROTATABLY RECEIVED IN SAID CAVITY AND INCLUDING A SPIDER DEFINING ALTERNATE DEEP AND SHALLOW BUCKETS OF DIFFERING RADIAL DEPTHS ARRANGED TO RECEIVE MATERIAL AT SAID INLET AND TO DISCHARGE MATERIAL AT SAID OUTLET UPON THE ROTATION OF SAID ROTOR, THE MATERIAL OF SAID SPIDER BEING DISTRIBUTED WITH A SUBSTANTIAL PORTION THEREOF LYING IN THE OUTER HALF OF THE ROTOR RADIUS TO RESIST BENDING BY PRESSURE AT SAID OUTLET, SAID BUCKETS HAVING SUBSTANTIALLY CYLINDRICAL BOTTOMS WITH THE BOTTOMS OF SAID DEEP BUCKETS HAVING A SMALLER RADIUS THAN THE BOTTOMS OF SAID SHALLOW BUCKETS.