US3836070A

US3836070A - Method and apparatus for discharging the waste as well as enhancing the flocculation of the suspension and moving the waste in solid jacket centrifuges

Info

Publication number: US3836070A
Application number: US00209881A
Authority: US
Inventors: H Trawinski
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-12-22
Filing date: 1971-12-20
Publication date: 1974-09-17
Anticipated expiration: 1991-09-17
Also published as: SE378767B; BR7108513D0; DE2063063A1; BE777088A; ZA718562B; GB1369020A; CH548797A; DE2063063C3; NL164762B; NL164762C; AT312534B; NL7117545A; IT944207B; FR2119756A5; DE2063063B2

Abstract

Method for discharging the waste and enhancing the flocculation of the suspension and the movement of the waste in solid jacket centrifuges by applying jolts to the drive means by braking or acceleration in order to open or close the waste discharge apertures and impart jolts to the compacted material. The centrifuge is equipped with a shaft through which the suspension is supplied and power transfer means such as spokes between the shaft and the drum jacket which has discharge apertures into which the ends of the spokes extend where the spokes are provided with means to open and close the discharge apertures and means for varying the speed are associated with the shaft which impart jolts to the transfer means.

Description

United States Patent 91 Trawinski Sept. 17, 1974 METHOD AND APPARATUS FOR DISCHARGING THE WASTE AS WELL AS ENHANCING THE FLOCCULATION OF THE SUSPENSION AND MOVING THE WASTE IN SOLID JACKET CENTRIFUGES [76] Inventor: Helmut Franz Trawinski,

Fasanenweg 24, D. 8452 Hirschau/Bavaria, Germany [22] Filed: Dec. 20, 1971 [21] Appl. No.: 209,881

[30] Foreign Application Priority Data [56] References Cited UNITED STATES PATENTS Hinchley et al 233/19 R Maclsaac 233/24 Egg 233/23 R 5 7 ABSTRACT Method for discharging the waste and enhancing the flocculation of the.suspension and themovement of the waste in solid jacket centrifuges by applying jolts to the drive means by braking or acceleration in order to open or close the waste discharge apertures and impart jolts to the compacted material. The centrifuge is equipped with a shaft through which the suspension is supplied and power transfer means such as spokes between the shaft and the drum jacket which has discharge apertures into which the ends of the spokes extend where the spokes are provided with means to open and close the discharge apertures and means for varying the speed are associated with the shaft which impart jolts to the transfer means.

18 Claims, 9 Drawing Figures PAIENIEDSEPWIHH 3.836.070

SHEET 1 (1F 5 mam-m PATENIEDSEP 1 7 m4 SHEET Q 0? 5 PATENTED I 3.836.070

SHEET 5 BF 5 METHOD AND APPARATUS FOR DISCHARGING THE WASTE AS WELL AS ENHANCING THE FLOCCULATION OF THE SUSPENSION AND MOVING THE WASTE IN SOLID JACKET CENTRIFUGES BACKGROUND OF THE INVENTION The invention relates to centrifuges, and particularly to the removal of waste in solid jacket centrifuges. More in particular, the invention concerns a method and related means for discharging the compacted waste in solid jacket centrifuges by means of waste discharge apertures in the drum casing, as well as for enhancing the flocculation of the portion of solid substance of the suspension to be compacted and the movement of the compacted waste. The field in which the invention is utilized involves all suspensions from which solid components are separated by the centrifugal force. In this connection the clearing of drain or waste water and the separation of the solids out of suspensions in the chemical industry are mentioned merely as examples.

For discharging the waste, apertures of relatively small cross-section, like nozzles, are known in centrifuges through which the departing waste flows uninterruptedly. Such nozzles can readily clog. Besides, the wear effects relatively large expansion of the cross section within a relatively short time. Above all, it is a disadvantage here that the control or regulation of the waste discharge is not possible.

Mechanical conveyance arrangements that are complicated as to structure are known for the waste conveyance within the centrifuge. Centrifuges are also known whose jacket that surrounds the sedimentation space is disposed conically where the inclination of the cone to the longitudinal axis of the centrifuge is rela tively large. The compacted waste or slurry here can slide under the effect of the centrifugal force in the direction of the outlet. A drum jacket of such conical shape involves the shortcoming that its greatest outer diameter must be rather large in relation to the diameter of the liquid level of the circulating suspension which with a certain centrifuging effect results in relatively high centrifugal forces in the region of the liquid level at the outer diameter of the jacket. Thereby also the effective clearing surface area is reduced which is obtained as the product of the cylindrical surface of the fluid level and the acceleration factor.

It is known with solid jacket centrifuges having a continuous overflow stream to add highly molecular flocculating agents and to essentially reduce the rotational speed of the motor in order to increase the clearing effect. However, this involves the disadvantage of expensive construction and long mixing stretches in order to bring the solid particles of the suspenion and the chain molecule aggregates of the flocculating agents in intensive contact with each other.

SUMMARY OF THE INVENTION It is an object of the invention to effect with a single process measure while avoiding the above shortcomings, the discharge of the compacted waste in a regulated and controlled manner by means of waste discharge apertures, as well as also to promote the movement of this waste within the drum jacket and the flocculation of the solid substance parts in the suspension. In connection with this, also the method of the feeding of the suspension supply is to be improved. The means required for carrying out this method are to be of simple construction.

In order to solve this problem, the invention proposes first as a measure of the method that by braking or accelerating jolts upon the drive the waste discharge openings are opened and again'closed, and the compacted waste is subjected to jolts in a direction that is tangential to the drum jacket. These jolts are applied to the centrifuge that rotates at rated speed so that no larger kinetic energies have to be introduced or destroyed. The waste discharge openings may be relatively large in cross section. Control or regulation of their opening time and the duration of the intermediate closing periods can be readily obtained by suitable control or regulation of the braking or acceleration jolts.

Furthermore, these jolts impart shearing forces and a fine turbulence to the suspension. In this manner the flocculation is enhanced and that with the addition of flocculating material, as well as also in connection with the self-flocculation of the suspension.

The braking or accelerating jolts may furthermore be made of such magnitude that in addition they effect, or at least promote, releasing of the limit layer between deposited waste and the inner wall of the drum jacket; Interfering re-whirling of the sedimented particles need not be expected because the jolts in accordance with the invention occur at intervals of such length that between two jolts there is sufficient time that the interference impulses due to the internal friction of the carrier liquid can dampen out and are not effective until the overflowing of the liquid occurs. The adhesion friction between the disposed waste and the inner wall of the drum jacket is, however, reduced by the jolts so that the migrating of the waste along the sedimentation section of the drum jacket is enhanced in the direction toward the waste outlet. Thus, it is not necessary as with known centrifuges to provide the sedimentation section of the drum jacket with a strongly inclined taper toward the axis of the centrifuge.

The aforementioned shearing forces decrease due to the braking and accelerating jolts from the drum jacket inwardly in the direction of the liquid level of the suspension load that surrounds the drive shaft. For the further enhancement of the flocculation in the entire area of the suspension load the invention further provides that the circumferential velocity of the entering suspension supply is greater or smaller than the suspension load that is already in the centrifuge, while the suspension supply is introduced in the same direction of rotation as the circulation of the suspension load. The difference of speed resulting here between the suspension supply and the suspension laod effects a further increase of the flocculation and that most strongly in the proximity of the liquid level of the suspension supply. This effect decreases in the direction toward the drum jacket and thus supplements in an advantageous manner the flocculating effect of the braking and the accelerating jolts described above. In a like manner as the strength and duration of the braking accelerating jolts, the difference in velocity between the suspension supply and the circumferential velocity of the suspension load can be varied by regulating. Besides, these two factors are adjustable relative to one another in the cycle of the change. Thus, one can adapt ones self to existing operating conditions and thus obtain optimum flocculation effects and clearing results.

The inventionfurthermore concerns an arrangement for carrying out the explained method where the driving moment is initiated by a shaft with the aid of transfer elements in the drum jacket. For this purpose, the invention provides that in addition to the drive, a braking or accelerating means is provided that acts upon the shaft. These may be in the form of braking or coupling members that can be rapidly connected and disconnected which act on the drive shaft or on rotating machine parts that are rigidly or elastically coupled therewith. Examples of such braking or coupling elements are friction couplings that can be brought into engagement with non-rotating machine elements or such hav ing a lower or higher speed of a sufficient moment of inertia that may be variable, furthermore mechanical brakes, magnetic brakes, eddy current brakes, brake generators, and the like. In this connection the different moments of inertia-of the drum jacket and the driving star can be utilized. The intensity and the duration of the braking or accelerating jolts can be chosen in accordance with the accumulating waste.

The opening and closing of the waste discharge openings by means of braking and acceleration jolts can be realized in different ways. In accordance with a preferred embodiment of the invention, a driving star rigidly connected with the drive shaft serves as transfer element in this connection which is tumable by a limited angle relative to the drum jacket and in force transferring engagement at its free ends with the drum jacket in both directions, directly or indirectly by means of ratchets or stop abutments, while in the phase of the driven course and the accelerating jolt, the waste discharge openings are closed by means of the free ends of the driving star, or covering devices provided thereon, while they are open after rotation of the driving star as a result of a braking jolt or a non-driven run. Thus, depending on its angular position, the driving star effects the opening or closing of the waste discharge openings.

The increase or decrease of the number of rotatiions of the supply suspension can be obtained in different ways. In accordance with a preferred embodiment of the invention the outflowing clear liquid of the centrifuge serves for this purpose while this clear liquid has imparted to it the increased or decreased number of rotations by means of a paddle wheel device. The particu-' lar turbine wheel of this device is coupled with the supply or feed device of the suspension supply, for example a sleeve.

BRIEF DESCRIPTION OF THE DRAWINGS Further advantages and features of the invention will appear from the following description of several embodiments with reference to the respective drawings which are essentially schematic and in which FIG. 1 shows a longitudinal section of the centrifuge in accordance with the invention with two different devices for obtaining a brake jolt,

FIG. 2 is a longitudinal section of an embodiment of the drum jacket,

FIGS. 37 are cross sections of different possibilities for closing and opening the waste discharge openings taken about along the line AA in FIG. 2, and

FIGS. 8 and 9 are longitudinal sections of embodiments of hydraulic accelerating devices for the supply suspension.

DESCRIPTION OF THE INVENTION The application of the method in accordance with the invention is not limited to the embodiment illustrated. In accordance with the invention the embodiment of a solid jacket centrifuge illustrated in FIG. 1 comprises, among other things, a drive shaft 1 and the drum jacket which in principle consists of the central waste collecting part 2 and the sedimentation parts or sections 3, in which connection the waste discharge openings are indicated at 5 and the over-flows for the clear liquid at 21. In the present example this is a continuously operating removal device for the clear liquid, preferably a rotation symmetric overflow weir. The suspension supply is fed, in accordance with arrow 6, through the interior of the shaft 1, whence it reaches through its openings 7 the supply means serving for its preliminary acceleration, which in this case is a sleeve 8a, and finally through the discharge apertures 8b thereof the rotating suspension load, the level and load of the centrifuge being indicated in dot and dash lines. Construction and effect of this sleeve as well as of its drive are explained in detail hereinafter.

The moment of rotation of the shaft 1 is passed on by a transfer element, in this case a driving star 9, to the jacket of the drum 2, 3. A coupling or braking device 10 serves for the braking of the shaft 1 for a short period of time. The additional initiation of the interference with the moment of rotation for causing a braking or acceleration jolt can, in accordance with the illustration in FIG. 1, lower right, also be realized in that a coupling 22 that rotates with the shaft 1 and is connected therewith can be brought into engagement for a short period of time with a rotating braking element 23. This element has a moment of inertia (fly wheel effect) which, as compared to the inertia effect of the rotating system, i.e., the actual centrifuge, constitutes a worthwhile partial amount of, for example, 5 to 10 percent. The number of rotations of the braking element 23 is less than that of the rotating system. As soon as the coupling is brought into engagement with it, the inertia moment of the braking element 23 must be brought to the full number of rotations of the rotating system with a shock or jolt. Since no additional driving energy is introduced, a number of rotations is established in a shortest manner, which is disposed between the original number of rotations of the rotating system and that of the rotating braking element 23. The moment of inertia of this braking element 23 can still be increased in that it is equipped with a non-centrifuge regulator, which at the moment of the coupling, and therefore with increase of the number of rotations, effects a sudden or jolt-like increase of the moment of inertia of the braking element 23 (not-illustrated). In this manner the intended aim of a sudden or jolt-like reduction in numbers of rotation of the rotating system is obtained to an increased extent without a large rotating mass. The braking element 23 is journalled on the shaft 1 by way of ball bearing 24 and can be held at its reduced number of rotations by a special drive, not illustrated in the drawings, for example a friction drive which is automatically separated as the coupling engages.

A sudden change of the velocity of the driving star 9 of the rotating drum jacket, whether it be by brief operation of a brake or by a short time increase of the drive moment and the termination of this change in speed, can effect the described braking and acceleration jolts. By these means the opening and closing of the waste discharge openings is controlled. This is explained in detail with reference to FIGS. 3 to 7.

Additionally there results the enhancement of the flocculation and at corresponding strength of the jolt also the effect of an axial movement of the condensed waste out of the sedimentation sections 3 of smaller diameter to the collecting section 2 of larger diameter of the drum jacket. With each braking or acceleration jolt there results a tangential displacement of the inert waste on the inside of the sedimentation sections 3. This is sufficient for eliminating the retaining forces between the waste and the inside surface and the intended axial movement by utilizing the centrifugal force also with a relatively small inclination of the comers defined by the sedimentation section which opens in the direction of the collecting part. The ratio of the outer diameter 144 of the sedimentation section 3 to the diameter of the liquid level of the rotating suspension load is favorable (see also FIG. 2). This effect can still be increased by guide worms having one or several grooves or scoops 12 or shutter-like claws 13 which are rigidly connected with the sedimentation section 3, for example by welding. During the braking phases the waste slides in steps to the flanks of the worms, moving helically in the direction of the waste collecting part. If worms or claws of this type are used, the sedimentation sections 3 may even be cylindrical in shape, if the jolts are sufficiently strong.

The waste collecting part 2 has a cylindrical section 16 centrally thereof with waste discharge openings 5 and two walls 17 laterally thereof having steep conical form, on which the waste can slide outwardly without auxiliary transport means. The sedimentation section 3 may, as indicated at 18, be releasably threaded together with the front ends of the waste collecting section 2, and are thus readily exchangeable with other sedimentation sections, for example, of different inclination or magnitude.

With this form of construction of the drum jacket the spokes 19, 20 that are supported on bearings on the shaft may be provided relatively close to the center of the centrifuge on both sides of the driving star 9. Thus also the discharge openings 8b of the supply device 8a may be nearly at the center of the centrifuge. The discharge openings 8b are directed outwardly and simultaneously to the collecting section 2,-so that more solid and thick waste parts reach the bottom of the waste collecting space as rapidly as possible, i.e., the inside of the wall 16. In addition it is advisable to have the outlet openings merge proximate the surface of the suspension load.

As a further development in accordance with the invention the transfer element which effects the transfer of power to the drum jacket carries or constitutes the covering devices for the waste discharge openings. In accordance with a further development of the invention a structurally particularly simple and effective arrangement for the transfer of the braking or acceleration jolt to the drum jacket is that the drive star 9 is not rigidly connected with the drum jacket 2, 3, but is turnable through a limited angle relative thereto and comes into engagement with its free ends with the drum jacket in both directions of rotation directly or by way of ratchets or stopping abutments. If the shaft driven at a normal number of rotations and the drive star rigidly connected with it is suddenly braked, then the power transfer between the drive star and the drum jacket is interrupted, and the drive star moves backward by the aforementioned angular amount relative to thedirection of rotation due to the greater inertia of the drum jacket, because due to its greater mass inertia the drum continues to move with almost the same angular velocity. The larger the angle of rotation is, the larger will be the braking jolt. If the brake is released, the drive star snaps back to the initial position due to the full driving force that is again imparted to it by the shaft, and again comes into force transmitting engagement with the jacket of the drum. Such jolts can also be obtained by sudden acceleration or retardation of the drive itself.

As the drive star is turned through a certain angle relative to the drum jacket, the waste discharge apertures are closed during the phase of the driven run and of the acceleration jolt by the free ends of the drive star, or are closed by the covering devices thereon, while on the other hand they are closed after turning of the drive star as a result of a brake jolt or a delay in the drive.

For this purpose FIG. 3 shows cams or projections 4 that extend inwardly from the drum jacket, which on one side constitute the driver 4' and on their other side the stopping abutment 4' Besides, the waste discharge openings 5 pass through these cams or projections 4 and open up at the abutment side 4'. In this manner the ends of the drive stars or their covering devices can during the closing phase sealingly engage the abutment side 4 with their sealing surfaces 9. The apertures 5 are closed. Moreover, in accordance with FIG. 3 they are directed opposite to the driving direction indicated by the arrow.

If the shaft 1 is braked, the drive star remains behind and comes into engagement with its surface 9" with the counter surface 4" of the next cam or abutment that constitutes the stopping abutment. During this release of the openings 5 the waste can emerge. If the braking of shaft 1 is discontinued, then the drive star 9 again runs ahead and arrives in the position illustrated. The angle or passed through by the drive star arms can be chosen to be of different size as long as the waste discharge is insured.

In the embodiment in accordance with FIG. 4 the drive star arms 9 are tiltably mounted in the direction of rotation by a limit angle B, on a collar 28 of the shaft 1, whereby a corresponding relative movability of shaft 1 with respect to the drum jacket is obtained. The free ends of the drive star arms extend into the waste discharge openings 29 of the drum jacket. During normal operation in the direction of rotation the apertures 29 are opened (illustration in solid lines). As the shaft 1 is braked, they tilt about the angle B and due to the change of the angle of penetration, they partly open the slot-like apertures 29 (illustration in dashed lines). The surface of the collar is so constructed that it limits the tilting of the arms but at the same time permits it through the angle [3.

In order to obtain a better sealing effect and also in order to dampen the acceleration and braking jolts, there may be elastic dampening means at the drivers or stopping abutments, respectively the corresponding surfaces of the drum jacket or on associated abutment surfaces of the drive star arms. One possible embodiment of this dampening is illustrated in FIG. 5. The drive star arms 9 are provided with sealing elements 30 which during the starting phase come into engagement with the counter surface of the slot 31 of the drum jacket. The opposite side of the waste discharge opening is closed by an elastic deformable seal 32 which serves at the same time for the dampening of the jolt. With a braking jolt these members 32 are compressed and free a passage for the waste between the sealing e]- ement 30 and the surface of the slot 31.

In the embodiment in accordance with FIG. 6 the drive star arms 9 are provided with sliding shoes 33 which are surrounded by a sealing material 34. During the starting phase they are in engagement with the drive edge 36 of the drum jacket and thus seal the slot 35. During the braking phase, however, they are in engagement with the rearward stopping abutment 37 and thus open the slot 35.

Furthermore, it is possible to control or regulate the position of the covering device of the waste discharge openings by coaction of the force of inertia and the centrifugal force, in which connection the opening and closing of the waste discharge openings is effected by a change in the force of inertia, which likewise results from braking or acceleration jolts. This is explained more in detail in the embodiment of FIG. 7. The drive star 27 performs the task of a spoke cross, and for this function it is firmly connected with the jacket of the drum. It is provided with angularly shaped tilting levers 38 which are pivotally connected to it and which have counter-Weight arms 38 that extend inwardly. During the driving phase the counter-weight arms stay back due to their inertia, so that the outer arms of the levers 38 close the waste discharge openings 39. During the braking phase, however, the inertia effects the tilting of these levers and thus the freeing of the openings 39 for the discharge of the waste. As a result of a new driving jolt the position illustrated is restored.

The cross-section of the waste discharge openings can be made relatively large, because the invention provides on the. one hand relatively short opening periods, for example fractions of a second, and on the other hand longer time intervals between two opening phases, for example fractions of a minute. Thus the time intervals between two jolts in this case are large in relation to the duration of the individual jolt. Large crosssectional openings of the waste discharge nozzles or slots, however, are desirable, because they can be produced in essentially simpler fashion than nozzles or slots of smaller diameter. Also, the danger of clogging is less. To this is added that the wear that necessarily results with the discharge of the waste requires a relatively larger cross-sectional expanse for discharging the material surrounding the aperture at a smaller diameter of the opening than with apertures of larger diameter. The number of waste discharge openings of a centrifuge may be small, as shown in the drawings.

The invention also insures faultless discharge 0 smaller waste quantities, because the discharge is not continuous but takes place only during predetermined opening intervals which are interrupted by the closing intervals. Also, the separating of larger quantities of waste is possible because discharge openings of large cross-section are provided. As explained, the length of the closing and opening intervals can be controlled. In accordance with the invention it is preferable to provide regulation corresponding to the accumulating waste. This can be effected by the photocell 25, which in accordance with FIG. 2 is located in a place below the actual over-flow 21 or a secondary over-flow 26, and effects the opening of the waste discharge apertures as soon as a certain opaqueness or turbidity has developed. In this manner it is assured that only clear liquid overflows.

The secondary over-flow 26 consists of one or several bores which are located at the circumference below the liquid level. By these means it is accomplished that a small portion of the over-flow stream flows off continuously. As soon as opaqueness occurs at this location, an indication is provided that the waste level has grown beyond the level of the actual waste collecting space that is limited by the walls 17. This makes possible the connecting of the regulating means before the actual main over-flow becomes turbulent.

The means for supplying the suspension to the interior of the drum can be constructed in different ways, for example, in' the form of a sprinkler. In accordance with the above mentioned preferred embodiment the supply device is in the form of a pre-accelerating tube. The suspension enters through the socket-like exit openings 8b of the sleeve 8a into the cylindrical surface with the load suspension rotating above or below the velocity. The difference of the number of rotations may be attained by driving the pre-accelerating tube 8a of a particular independent drive shaft, for example a gear belt or chain drive. Also, the derivation of an additional moment of rotation is possible below the change of number of rotations of the shaft 1 by means of a gear unit 11 or a planet gear.

The change of the number of rotations of the preaccelerating tube 8a with respect to the speed of the drive shaft 1 can be obtained by using the over-flow stream of the centrifuge also with the aid of a hydraulic device.

Such an arrangement is illustrated in FIG. 8. It is provided at one of the two sedimentation sections 3 of the drum jacket and imparts to the supply suspension flowing out of the pre-accelerating tube a higher speed of rotation than the rotational speed of the suspension load rotating in the drum jacket. In addition, the clear liquid is supplied by way of the over-flow wier 21 to the interior of a paddle wheel 41 which is firmly connected with the sedimentation section 3. The clear liquid is conducted through the paddle wheel 41 outwardly to its largest diameter, and thereby accelerated to a rotational speed that is greater than the rotational speed in the area of the overflow wier. The energy required for this purpose is provided by the shaft 1 by way of the sedimentation section 3. The paddle wheel 41 is closed at both sides. Thus the clear liquid at the periphery of this wheel enters the annular space 43, which is devoid of paddles, located opposite a separating wall 42, in that it is conducted back inwardly. There results, due to the constrained construction of a Helmholtz-flow turbulation, an increase of the number of rotations and thereby a renewed increase of the circumferential velocity. Finally, the clear liquid thus accelerated leaves the rotor system that rotates with the drum jacket and is conducted into the interior of a turbine wheel 44 which is firmly connected to be carried along with the pre-accelerating tube 8a. The flowing of the clear liquid through the turbine wheel imparts thereto an increased velocity that is transferred to the tube 8a. The

liquid that leaves at the outer circumference of the turbine wheel 44 is conducted away'by means not illustrated. I

The increase of the circumferential speed of the supply suspension explained above obtains the further effect that due to its increased centrifugal force, it advances rapidly from the intake into the liquid level of the load suspension to the drum jacket.

However, it would also be possible to impart to the pre-accelerating tube and thereby to the supply suspension a velocity that is decreased with respect to the rotating speed of the drum jacket and of the load suspension. For this the simplified arrangement can be used that is illustrated in FIG. 9. The over-flow liquid is conducted directly to the outside in accordance with the arrow, by way of a turbine wheel 45 rigidly connected with the pre-accelerating tube 8a. Due to the increase of its radius, the liquid has imparted to it during an unchanged circumferential velocity a decreased number of rotations, as compared to the rotating drum jacket and the load suspension which is transmitted to the preaccelerating tube.

Having now described my invention, what I desire to protect by letters patent of the United States is set forth in the appended claims. 1

1. Method for discharging the compacted waste from solid jacket centrifuges provided with drive means by way of waste discharge apertures in the jacket of the drum of the centrifuge, as well as for enhancing the flocculation of thesolid portion of the suspension to be compacted and of the movement of the compacted waste, said method comprising the steps of opening the waste discharge apertures by applying jolts to said drive means by braking or acceleration to open and close the waste discharge apertures and imparting jolts to the compacted waste material in a direction tangential to the jacket of the drum.

2. Method in accordance with claim 1, where for the further enhancement of the flocculation by a decrease in velocity the circumferential velocity of the entering supply suspension is made greater or smaller than that of the load suspension which is already stationary in the centrifuge, while the supply suspension is introduced in the same direction of rotation as the rotation of the load suspension and discharging waste through the apertures in the drum.

3. Apparatus for discharging the waste as well as enhancing the flocculation of a suspension and the movement of the waste in solid jacket centrifuges, comprising a centrifuge having a drum jacket provided with waste discharge apertures, a shaft having force transfer means such as arms extending to said apertures and having ends adapted to open and close said apertures, and means associated with said shaft operative to change the rotational speed by braking or acceleration and thereby open said apertures and impart jolts to the waste materiaL.

4. Apparatus in accordance with claim 3, where the outer ends of said transfer means present cover devices for the waste discharge apertures. I

5. Apparatus in accordance with claim 4, where said transfer means is in the form of a driving star connected to said shaft for movement through a limited angle relative to said drum jacket and said drum jacket having abutment means proximate said apertures for engagement by said cover devices and means whereby during the running phase said apertures are closed, while upon change in the angular position resulting from the change of the speed of said shaft and resulting jolts said apertures are opened.

6. Apparatus in accordance with claim 5, comprising projecting configurations such as cams defining on one side driving configurations such as ratchets or the like, and on the other side stopping abutments.

7. Apparatus in accordance with claim 6, where the waste discharge apertures pass through said projections and are open at the ratchet side and the ends of said driving star are provided with sealing surfaces which are engagement with said apertures during aperture closed operation.

8. Apparatus in accordance with claim 5, where the free ends of said driving stars extend into said waste discharge apertures and ends of said driving stars and the waste discharge apertures are provided with sealing surfaces that are in engagement with each other during aperture closed operation.

9. Apparatus in accordance with claim 7, where jolt dampening means are provided intermediate said ratchets and said stopping abutments on the one hand and the ends of said driving stars on the other hand.

10. Apparatus in accordance with claim 4, comprising covering devices operatively responsive to inertia forces pivotally mounted proximate said apertures and having arms responsive to centrifugal forces to close said apertures and in response to jolts applied through said shaft to open said apertures.

11. Apparatus in accordance with claim 10 where said centrifuge includes overflow means and a photocell proximate said overflow means for measuring the turbidity of the fluid to thereby control the duration of the closing intervals and the opening periods.

12. Apparatus in accordance with claim 11 where said drum jacket comprises a central waste collecting section and two sedimentation sections connected to said collecting section and where said waste discharge apertures and the force transfer means are disposed in said collecting section.

13. Apparatus in accordance with claim 12 where means are provided on said drum jacket in said sedimentation sections such as guide worms, scoops, claws or the like, while the sedimentation sections are cylindrical or of small inclination relative to the axis of said centrifuge and open toward said collecting section, and said collecting section is provided with side walls steeply inclined relative to the axis of said shaft.

14. Apparatus in accordance with claim 3 comprising a supply device for introducing a pre-accelerated supply suspension disposed coaxially with respect to said shaft and rotatable therewith in the same direction at increased or decreased numbers of rotation.

15. Apparatus in accordance with claim 14, where said supply device defines a pre-accelerating means in the form of a tube having discharge openings for the supply suspension that are directed outwardly toward said collecting section to discharge proximate the surface of the load suspension.

16. Apparatus in accordance with claim 14 comprising a hydraulic drive means for said supply device separated by means of the overflow stream from said centrifuge.

17. Apparatus in accordance with claim 16, where said supply device includes a paddle wheel connected with the sedimentation section of the drum jacket for rotation therewith to impart acceleration to the supply device, said wheel having an intake and an outlet for the overflow stream of clear fluid, an annular space connected to said outlet adapted to return clear fluid inwardly, a turbine wheel in the annular space through which flows the clear liquid from said annular space outwardly and connected to said supply device for rotation therewith.

directly connected with the supply device.

Claims

1. Method for discharging the compacted waste from solid jacket centrifuges provided with drive means by way of waste discharge apertures in the jacket of the drum of the centrifuge, as well as for enhancing the flocculation of the solid portion of the suspension to be compacted and of the movement of the compacted waste, said method comprising the steps of opening the waste discharge apertures by applying jolts to said drive means by braking or acceleration to open and close the waste discharge apertures and imparting jolts to the compacted waste material in a direction tangential to the jacket of the drum.

4. Apparatus in accordance with claim 3, where the Outer ends of said transfer means present cover devices for the waste discharge apertures.

18. Apparatus in accordance with claim 16 where said hydraulic drive means includes a turbine wheel and for reducing the number of rotations of said supply device the clear liquid is conducted from the inside outwardly to said turbine wheel and said turbine wheel is directly connected with the supply device.