US2755991A - Discharger shoe apparatus for centrifugal separator - Google Patents

Description

July 24, 1956 THOLL ETAL 2,755,991

DISCHARGER SHOE APPARATUS FOR CENTRIFUGAL SEPARATOR Filed Aug. 8. 1952 5 Sheets-Sheet l July 24, 1956 J. F. THOLL ETAL DISCHARGER SHOE APPARATUS FGR CENTRIFUGAL SEPARATOR Filed Aug. 8, 1952 5 Sheets-Sheet 2 July 24, 1956 J. F. THOLL ErAL 2,755,991

DISCHARGER SHOE APPARATUS FOR CENTRIFUGAL SEPARATOR Filed Aug. 8, 1952 5 Sheets-Sheet 3 July 24, 1956 J. F. THOLL ETAL 2,755,991

DISCHARGER SHOE APPARATUS FOR CENTRIFUGAL SEPARATOR Filed Aug. 8, 1952 5 Sheets-Sheet 4 July 24, 1956 J. F. THOLL ETAL DISCHARGER SHOE APPARATUS FOR CENTRIFUGAL SEPARATOR Filed Aug. 8, 1952 5 Sheets-Sheet 5 W m, w a a Q Q m a m Q w 57% I AM 7 i 1 u .u n

g a a l'avea'afoaw flfiowraqy United States Patent DlS CI-IARGER SHOE APPARATUS FUR CENTRIFUGAL SEPARATOR 1 John F. Tholl and David M. Tholl, Needham, Mass, assignors to American Tool 8; Machine Company, Enston, Mass, a corporation of Massachusetts Application August 8, 1952, Serial No. 303,303

6 Claims. (Cl. 23310) This invention relates to an improved discharger shoe apparatus for use with centrifugal separators, and particularly with centrifugal separators of the class having a stationary outer casing or curb formed with an opening at the upper side thereof, which opening furnishes access to a rotatable basket received within the curb.

In devices of this general class heretofore proposed, it has been customary to utilize a manually operated positioning mechanism for swinging a shoe or scraper blade, commonly referred to as a discharger shoe element, inwardly in to a position of register with the curb opening, and then to raise or lower the shoe element in the basket in order to remove material which may be hardened or caked on the inner wall surfaces of the basket. Necessarily the operator, in order to carry out such an operation, is required to stand in close proximity to the separator mechanism, and since there is a very considerable danger of injury from the rapidly rotating basket, it has been the custom to stop the operation of the machine while making the manual adjustments of the control mechanism. This involved a loss of time and a generally less efficient operation. Moreover, as such stopping and starting may occur frequently, a very considerable torque stress problem develops in the rotary driving mechanism, and it is in many cases found to be necessary to provide in the rotary driving mechanism special torque arresting or cushioning devices adding measurably to the cost and bulk of the machine.

It is an object of the present invention to deal with these problems and to devise a discharger shoe apparatus for a centrifugal separator, including a control mechanism which operates automatically, with the result that having once been placed in motion, the discharger shoe may be positioned, as desired, at any time, while the centrifugal separator is running and without stopping this member. It is a further object of the invention to provide a control mechanism which, owing to its automatic operation, makes it possible to avoid or eliminate the use of expensive torque arrestors.

These and other objects and novel features will be more fully understood and appreciated from the following description of a preferred embodiment of the invention selected for purposes of illustration and shown in the accompanying drawings, in which Fig. 1 is a plan view taken on the line 1-1 of Fig. 2;

Fig. 2 is a side elevational view of the discharger shoe apparatus of the invention shown in one position of adjustment in association with a typical centrifugal separator of the class which includes a curb and a rotatable basket mounted within the curb;

Fig. 3 is a fragmentary vertical cross-sectional view of the structure shown in Fig. 2, and further illustrating the discharger shoe mechanism in another position of adjustment in which the discharger shoe element occurs within the basket;

Fig. 4 is a fragmentary plan cross-sectional. view taken on the line 44 of Fig. 3; 1

Fig. 5 is another plan cross-sectional view generally corresponding to Fig. 4 but showing a modified form of discharger shoe blade or element;

Fig. 6 is a detail cross-sectional view of the actuating means for one part of the discharger shoe mechanism;

Fig. 7 is an enlarged fragmentray plan cross-sectional view of portions of the discharger shoe apparatus taken on the line 77 of Fig. 3;

Fig. 8 is an enlarged vertical cross-sectional view of discharger shoe holder means and actuating means therefor, these parts being shown as aunit removed from the supporting structure indicated in Figs. 1 and 2;

Fig. 9 is a vertical cross-sectional view taken on the line 9-9 of Fig. 4; and

Fig. 10 is a perspective view showing the supporting base structure of the discharger shoe apparatus, including bearing portions and guide means from which parts of the shoe holder means shown in Fig. 8 have been removed.

In the structure shown in the drawings we have illustrated a typical centrifugal separator arrangement including vertical frame pieces, as 2 and 4, which are carried on bottom members 3 and 5, as suggested in Figs. 1 and 2. Solidly secured to upper portions of the vertical frame pieces 2 and 4 are transverse beams 6 and 8 which may, in turn, receive suspension beams 10.

The above described construction comprises a rigid frame work which is necessary to support a suspended driving motor 11 which, in turn, rotates a shaft 13 about a long vertical axis. As the length of this vertical axis must be kept. as small as possible, the height of the enclosure defined by the frame work described has definite limitations in order for the structure to properly support and rotate a basket 20 suspended at the bottom of the shaft 13 (Fig; 2). This basket is enclosed in the usual manner within a casingor curb 16 which is formed in its upper side with an opening 18 furnishing access to the basket 20. The curb may, for example, be supported on brackets 12 and 14, as shown in Fig. 2.

As an aid to more fully understanding and appreciating the discharger shoe apparatus of the invention, it is pointed out that basket sizes and depths may vary considerably. Thus, for many purposes, it may be found to be most efficient to provide for basket depths running up to as. much as thirty inches for a given diameter size, and in some cases this dimension may be increased. It will be apparent that the depth of the basket dictates, to a considerable extent, the length of the vertical travel through which a discharger shoe. element must pass in scraping or scavenging the inner wall surfaces of the basket.

With the foregoing considerations and limitations in mind, we have devised a special automatic discharger shoe apparatus which, in the preferred embodiment shown in the drawings, is suitable for use with any size basket within the range generally indicated above and without unduly interfering with the supporting frame work of the centrifugal separator and without requiring any change in the conventional operation of the centrifuging process.

This special discharger shoe apparatus generally comprises a means for moving a discharger shoe element or blade from a position above and outside of the basket and curb to a position of register directly above the openings in the curb and basket; also separate means for moving the discharger shoe downwardly through the opening in the basket into a position in which the blade or shoe occurs just below the upper flanged edge of the basket; and also means for selectively lowering and raising the blade while in contact or in close proximity to the inner surface of the curb. Furthermore, the means for rotating the blade about a vertical axis and for moving it into and out of the basket are capable of being reversed in their direction of movement.

In order to provide for automatically lowering and raising the discharger shoe while in the basket, we have found that it is important to employ a control which can be operated independently, and we have devised a special telescoping discharger shoe holder arrangement, the principal parts of which are included within the bracket A--A of Fig. 8. In accordance with the invention this shoe holder arrangement is supported in a suspended position above the curb so that it can be swung about a vertical axis, and yet can be raised and lowered as a complete unit without utilizing the telescoping action until a desired point of register is arrived at.

Considering first the means for supporting this telescoping shoe holder arrangement in a position such that it can be rotated about a vertical axis, we provide a supporting base structure which preferably is secured at the upper side of the curb 16 and which includes a base plate 22 adapted to be bolted to the curb. Extending upwardly from the base plate 22 is a reinforced hollow body section 24 which is formed at its upper end with a flat bearing surface 26, as better shown in Fig. 10. It is contemplated that other types of supporting base structures may be employed, for example one which might rest upon the floor and which might be movable toward and away from the centrifugal separator, at will. However, the invention will be described with reference to the permanently attached type of supporting base structure shown in the drawings, it being understood that the invention is not limited to this or any other particular form of base.

In the position of the supporting base structure shown in Fig. 7, its inner or right-hand side will be seen to be formed with an enlarged bearing portion 28 which is chosen of a size such that it projects inwardly over the inner edge of the curb 16, as is also shown in Figs. 2 and 3. The bearing portion 28 comprises a cylindrical member with a vertically extending bore formed therein. Received in this bore is a tubular guide 30 which is rotatable in the bore and which is also designed to slidably receive the telescoping shoe holder structure included in bracket AA, as noted above.

Resting upon the upper edges of the tubular guide and cylindrical bearing member 28 is a stop ring member 32, better shown in Fig. 9, which is formed with a keyway in which is received a key 34 for keying the stop ring to the tubular guide 30, as may be seen from an inspection of Figs. 9 and 10.

The stop ring is constructed on one side with a lug 32a and on an opposite side with a second lug 32b through which lugs are adjustably threaded respective stop elements 33 and 35. These stop elements are adapted to swing into engagement with a projecting part 37 formed on the bearing 28 and limit rotation of both the collar and guide about a vertical axis, as more fully described herein.

The tubular guide 30 has its outer peripheral surface formed with a gear portion 36 (Fig. and arranged to mesh with the gear portion 36 is a rack member 38 slidably supported in a second bearing member 40 formed horizontally along the upper part of the body 24. The rack member 40 is attached at one end thereof to suitable means for reciprocating the rack such, for example, as an air-operated cylinder and plunger unit generally denoted by the numeral 42 and shown at the right-hand side of Fig. 10 and also in Fig. 4.

As such an air-operated device is of well known character, no detailed description is thought to be required other thant to say that the rack is attached to a piston 42a which is reciprocally actuated by air admitted to the cylindrical portion 42b through two spaced-apart conduits 42c and 42d. These conduits connect with an electrically operated air valve 43 of conventional construction such, for example as an air valve sold under the trade name Electroaire. A conduit 45 serves to conduct air to valve 43 from a master valve 64 which is, in turn, connected to a source of compressed air through a conduit or pipe 64a.

Mounted on the flat surface 26 of the body portion 24, and securely attached thereto, as for example by fastenings such as bolts, is an upright member 44, best shown in Figs. 2 and 8. This upright member has an enlarged top flange section 46 upon which is mounted a vertically movable suspension unit from which hangs the telescoping shoe holder arrangement included in section A--A of Fig. 8.

Included in the suspension unit is a second air-operated cylinder and piston unit 48 of the same general character already described, including a cylinder 50, a plunger or piston 52 contained therein and having a piston rod 54, as shown in Fig. 6. Two conduits for admitting air to the cylinder 50 at either side of the piston are indicated by the numerals 56 and 58, respectively, and these conduits communicate with an electrically operated air valve 68, in turn connected to the master valve 64 already described.

The piston rod or stem 54 shown in Fig. 6 supports at its upper end an arm 66 which extends outwardly and has secured to its outer end, at the under side thereof, a threaded fitting 68 formed with two passageways 70 and 72. Threaded into these passageways are respective conduit members 74 and 76 which are connected to another air valve device 75 of the class described above. The air valve 75, in turn, is connected by a tube 77 to a master air valve 64. Also threaded into the bottom of the fitting 68 are two other tubular conduits 78 and 80 which com municate with the passageways 72 and 70, respectively, as is better shown in Fig. 8.

In accordance with the invention we mount the telescoping shoe holder structure included within the bracket A-A of Fig. 8 upon the outer tubular conduit 78, and at the same time we locate the lower part of the telescopiug structure in the rotatable guide 30, as shown in Fig. 8. By means of this arrangement it will be apparent that the entire suspension unit and the telescoping holder structure may be readily raised or lowered together when the air cylinder 48 is operated. Likewise it will be apparent that by slidably keying the telescoping holder structure in the tubular guide 30, this vertical movement may be accomplished and, at the same time, the telescoping holder may be rotated by the guide 30 and its rack 38 into different positions of adjustment which are described in detail at a later point.

Considering now in greater detail the telescoping unit it will be observed that at the lower end of the tubular conduit 78 and in threaded relationship therewithin, there is provided a plug member 82 surrounding the conduit 80 and secured by a locking unit 84 which is, in turn, threaded around the extremity of the conduit 80. Fixed on the outer peripheral surface of the conduit 78 adjacent to the plug 82 is a piston or plunger member 86 carrying piston sealing rings 83. The piston supports in sliding relationship with its peripheral surface a sleeve member 90 which is closed at its upper end by a threaded cap 92 and a gland nut 94. The piston 86, in its location shown in Fig. 8, occurs in an intermediate position relative to the ends of sleeve 90 and defines an upper chamber 96 and a lower chamber 98. Communicating with the upper chamber 96 is a passageway 100 which leads to the interior of the conduit 78 and, in turn, to the passageway 72 and its respective conduit 76. Communicating with the chamber 98 is the open extremity of the tubular member 80 so that there is formed a continuous passageway from chamber 98, through conduit 80, and thence through the passageway 70 and is respective conduit 74.

At the lower end of the sleeve 90 is internally threaded another plug member 102 which is provided with two serrated sections 104 and 106 normally held in locked relationship with respect to one another by means of adjustment nut 108, all as shown in Fig. 8. The lowermost section 106 has solidly fixed to it a blade holder 112 which carries a discharger shoe element 114 of the well known blade type.

At its outer peripheral surface the sleeve 90 is formed with a vertical keyway and, similarly, the tubular guide 39 is formed with a complimentary keyway, in which keyways is located a key 93, as shown in Fig. 8. This key member allows the tubular guide to turn the sleeve 90 with it when rotated by the rack 38.

It will readily be seen that since the sleeve 90 is slidably mounted on the outer conduit 78 and is also slidably keyed in the tubular guide 30, it is free to move either up or down. To produce movement of the sleeve, and its holder portions vertically, compressed air may be released into the chamber 98 through the passageway 70 and thence out through the conduit 80; The pressure thus exerted causes the sleeve to slide downwardly on the piston 86 to a desired point. Alternatively, to raise the sleeve and its holder, compressed air is released into the chamber 96. This may be done by opening the valve which controls flow of compressed air through the conduit 76 and into passageway 72 and thence through the conduit 70 and out of the ports 100. Pressure will then be exerted in the chamber 96 and this will cause the sleeve to move upwardly relatively to the piston 86. By selecting a sleeve length of the proper magnitude it will be readily understood that we may provide for a length ofstroke which will be adequate to move the discharger shoe 114 all the way up and down the inner peripheral surface of the basket 20.

In the operation of our discharger shoe'the telescoping sleeve and shoe holder structure will normally be located in a raised starting position, as shown in Fig. 2. In this position the discharger shoe has been moved into a location above the curb and basket, as shown, and moreover the shoe has been rotated about a vertical axis into a position, for example, in which the blade occurs immediately above the top side of the curb, as suggested in Fig; 2.

Assuming now that a centrifuging operation is nearing a point of completion and it is desired to apply the discharger shoe to the inner peripheral surface of the basket 20, the master valve 64' may be opened and this is followed by a series of timed movements in the selector valves 43, 60 and 75. Ordinarily the first movement is to produce rotation of the tubular guide and telescoping sleeve about a vertical axis. This is accomplished by means of the member 43 which, when opened, produces a transverse movement of the piston 42a and, with. it, the rack 38 which acts through the segmental gear portion on the tubular guide to move thedischarger shoe inwardly above the openingin the curb.

In Fig. 7 We have illustrated fragmentarily portions of the stop ring mechanism and the discharger shoe. shown in one typical position with the stop element 33 located against the projection 37. The inward. rotation of the tubular guide and telescoping holder operates to swing the member 114 into the broken line. position shown at the right-hand side of Fig. 7, and it is pointed out that this inward rotation of the discharger shoe is controlled and limited by the adjustable stop. element 35 which, at one point, comes into engagement with the projection 37 to prevent further rotation.

With the discharger shoe in the broken line position shown in Fig. 7, the member 60 is next opened to deliver compressed air into the cylinder 50 of the vertically movable suspension unit. The pressure of this compressed air delivered through the conduit 56 causes the piston 52 to descend and carry with it the extension arm 66 and the telescoping unit throughout a short path of travel. In one satisfactory type of operation it has been found that a travel of approximately seven inches by this suspension unit will produce a suflicient change in position of the discharger shoe to locate it just below the flanged edge of the basket 20, as noted in Fig. 3.

In order to move the discharger shoe into engagement with, or into close proximity with respect to, the inner peripheral surface of the basket, it will be understood that the rack member, through the valve mechanism already described, has to be reversed to rotate the tubular holder and shoe in an outward direction. This is done by conventional switch means in the Electroaire valve 4-2. Thereafter compressed air is admitted through conduits 70 and 78 to the chamber 98 by means of the valve 75, operating in the manner already described, to cause the sleeve member to descend and carry with it the discharger shoe member throughout the length of the basket wall into a position, for example, such as that shown in dotted lines in Fig. 3. The precise arrangement of the extremity of the discharger shoe may vary, depending upon the thickness and consistency of the material which may be coated or caked around the inside of the sep arator and which is required to be removed. In some instances, for example, it may be preferable to adjust the end of the discharger shoe so that it does not actually engage the basket periphery but merely presses firmly against the cake as the basket rotates around its axis. This action gradually scrapes or removes caked material. In other cases where a very soft body is adhering to the basket wall, the shoe may be rotated all the way inwardly to the point where it immediately begins to contact por tions of the basket periphery.

As soon as a proper scraping or scavenging action has been achieved within the basket, the discharger shoe may beeither raised into the position which it occupies in Fig.- 3, or it may be first swung away from the basket wall and then raised into a position above the curb and basket, and finally rotated out to the starting position noted above.-

To' cause the discharger shoe to rise into its full line position of Fig. 3 the telescoping holder structure is operated by reversing the action of valve 75 and causing air to flow into the conduit 72 which escapes through the ports 100' and causes the sleeve member 90 to rise. in the same manner the rack may be actuated by reversing its control valve to swing the discharger shoe inwardly away from the basket and curb edges, and thereupon the suspension unit is operated by the valve 60 to raise the piston 52 and piston rod 54 with the arm 66. Thereafter the rack is again operated toswing the shoe out to its starting position.

We may also desire to employ the mechanism described with various other types of discharger shoe elements. Thus, in Fig. 5' we have shown a discharger shoe element which is solidly secured to a telescoping holder-struc ture rotatable in a tubular guide 122. The discharger shoe in this arrangement extends inwardly and angularly against the path of rotation of the basket 124, as has been suggested in dotted lines in Fig. 5. Thus the shoe opposes the rotation of the basket, and the force of the haskettends to cause the shoe to be forced outwardly against the wall of the basket by the leverage applied". This type of discharger shoe element may be preferable for certain types of hard caked material which is not readily displaced from the basket periphery.

It should be understood that various other modifica tions and changes may be resorted to. For example, we may provide suitable relay control, means for operating; the selector valves 43, 60 and 75 in a different sequence or in a fully automatic sequence, so that by merely closing one control switch all of the other switches will be operated in a predetermined sequence in accordance with well known relay timing devices of this general class. Similarly, we may vary the actuating means employed. For example, in place of air cylinders and reciprocating plungers or pistons, we may employ an hydraulic type of control Where a fluid, such as a liquid under pressure, is utilized to comprise the actuating force. Various other electrical arrangements also may be utilized, if desired.

From the foregoing description of our invention it will be evident that we have provided a rugged, dependable,

"7 and eflicient discharger shoe control mechanism in which we have made provision for a positive stop to cause the discharger shoe to enter, on its down stroke, very accurately under the basket cap or flange. It is pointed out that it is very important that this particular step be carried out in such a way that no chance of error or failure of operation can arise. By employing the cylinder 50 and the plunger 52, the seating of the plunger in its cylinder constitutes a positive mechanical control when, when once set, will permanently remain in effect to always ensure the correct location of the discharger shoe blade at the time it is swung outwardly against the basket wall. Obviously the same accurately and permanent stop arrangement is present on the upstroke when the piston 52 seats against the top of the cylinder member 50.

It is also pointed out that a second point of unusual strength and rigidity in the construction of the working parts is derived from the novel telescoping holder arrangement wherein the scraper blade, instead of being supported at the end of a piston stem or shaft, is supported by means of a cylindrical sleeve of relatively large diameter which tends to develop relatively greater rigidity and strength than could be obtained with any reciprocating plunger or piston construction.

Moreover, the mechanism described is particularly suited to meeting with safety requirements. For example, the controls may be arranged so as to leave pressure on the cylinder 42 at the end of the rotary cycle so that the discharger shoe element will always be locked in a safety position above the first curb top. In the event of air or fluid pressure failure this discharger shoe element cannot accidentally move into a position of interference. It is further contemplated that the controls may be electrically connected with the actuating means for rotating the centrifugal separator and also with various well known mechanisms for applying a braking action to the separator when in motion.

While We have shown a preferred embodiment of our invention, therefore, it will be understood that said invention is limited only within the scope of the claims as appended hereto.

Having thus described our invention, what we desire to claim as new is:

1. A discharger shoe mechanism for a centrifugal separator of the class having a rotary basket and a curb in which the basket is enclosed, said discharger shoe mecha position in which the shoe element may be lowered into the said basket and then rotated into engagement with the basket, and means for lowering and raising the shoe element and bolder while within the said basket, the said means for rotating the shoe and holder including a base member mounted on the curb, said base presenting a bearing portion, a tubular guide rotatably received in the bearing portion, a sleeve member forming a part of the holder means and being operatively connected to the tubular guide, and gear means located through the bearing portion for rotating the tubular guide.

2. A structure as defined in claim 1, including means for producing reciprocating movement of the sleeve member in a vertical direction.

3. A structure as defined in claim 1, in which the vertically disposed holder means comprises a telescoping sleeve, a hollow shaft having the sleeve telescopically mounted thereon, a piston carried on the shaft and adapted to slidably receive the telescoping sleeve, said shaft being formed with fluid conduits which communicate with spaces occurring within the telescoping sleeve at either sideof the piston.

4. A discharger shoe control mechanism for a centrifugal separator of the class having a rotary basket and a curb in which the basket is enclosed, said discharger shoe control mechanism including a discharger shoe element presenting a scraper blade, a vertically disposed holder for supporting the shoe element in suspended relationship above the said curb, said holder comprising an outer tubular member having the said shoe element attached at the lower end thereof, hollow shaft means for slidably supporting said tubular member, fluid pressure responsive means for moving the said tubular member relative to its hollow shaft, means for raising and lowering the tubular member and its supporting parts as a unit, and means for rotating the tubular member and shoe element about a vertical axis in any position of vertical adjustment.

5. A discharger shoe mechanism for a centrifugal separator of the class having a rotary basket and a curb in which the basket is enclosed, said discharger shoe mechanism including a discharger shoe supporting structure having a base adapted to be secured at the upper side of the curb, said base presenting a bearing portion formed with a vertical bore therein, a tubular guide member received through the bore of the bearing portion and rotatable therein, said tubular guide presenting at its outer periphery a gear portion, said base further including a second bearing portion formed with a transversely disposed bore, a rack member slidably received through the transversely disposed bore in a position to engage with the gear of the tubular guide, means for reciprocating said rack, a discharger shoe holder unit including a sleeve member slidably keyed in said tubular guide, a discharger shoe element rigidly secured at the bottom of the sleeve member, a piston received in the sleeve, fluid pressure means for raising and lowering the discharger shoe holder unit, and fluid pressure means for reciprocating the sleeve relative to the said piston.

6. A structure as defined in claim 5, including a stop ring supported above the said first bearing portion in keyed relationship with the tubular guide, and a stationary stop piece arranged on the said first bearing portion in position to limit rotary travel of the said stop ring.

References Cited in the file of this patent UNITED STATES PATENTS 1,202,936 White Oct. 31, 1916 1,620,568 Ordway Mar. 8, 1927 1,965,840 Jones July 10, 1934 1,968,491 Jones July 31, 1934 2,063,472 Tholl Dec. 8, 1936 2,234,332 Brewer Mar. 11, 1941 2,467,023 Foster et al Apr. 12, 1949 2,628,719 Hertrich Feb. 17, 1953

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