US2254388A - Cover for centrifugal machines employed in the extraction of sugar from sugar bearing materials - Google Patents

Description

Sept. 2, 1941. 3. o co 2,254,388 COVER FOR CENTRIFUGAL MACHINES EMPLOYED IN THE EXTRACTION 0F SUGAR FROM SUGAR BEARING MATERIALS Filed March 27, 1959 2 Sheets-Sheet 1 CIA. OLCOTT I BY A ATTORNEY Sept. 2, 1941. c, QLCOTT 2,254,388 COVER FOR CENTRIFUGAL MACHINES EMPLOYED IN THE EXTRACTION 0F SUGAR FROM SUGAR BEARING MATERIALS Filed March 2'7, 1959 2 Sheets-Sheet 2 FIG. 3

r0 coumsssw AIR mp0 sow/vow VALVE INVENTOR C. A. OLCOTT A 7' TORNE V Patented Sept. 2, 1941 r s ATE-NT QE COVER FOR CENTRIFUGAL MACHINES EM- PLOYED IN THE EXTRACTION OF SUGAR FROM SUGAR BEARING MATERIALS This invention relates to the automatic closing of machines and more particularly to covers for centrifugal machines employed in the extraction of sugar from sugar bearing materials.

An object of this invention is to increase the eficiency of centrifugal machines employed in the extraction of sugar from sugar bearing materials.

Another object of this invention is to prevent the dissipation of energy normally resulting from the operation of centrifugal machines.

Another object of this invention is to increase the ratio of operating to idle time of centrifugal machines.

In the processing of sugar from sugar bearing materials, such as magma and massecuite, the sugar bearing material is introduced into a centrifugal machine comprising a basket suspended from a shaft. After the desired amount of magma or other sugar bearing material is placed in the centrifugal, the shaft is rotated at relatively high speed. During this operation, the sugar which is precipitated in the magma is retained in the basket and removed from time to time. To secure the maximum yield of sugar, the magma introduced into the centrifugal is within a limited temperature range which is materially higher than the ambient. The heat developed in the centrifugal is utilized to maintain the magma within this range. It is essential, therefore, for maximum efiiciency, that the heat produced by the centrifugal be not dissipated by the air currents which, if the centrifugal is uncovered, pass through the opening therein. Since the centrifugal has a small capacity and is charged and discharged frequently, it is desirable that the charging and discharging of the centrifugal be practised while the speed of the machine is reduced but not stopped. Covers have heretofore been proposed for closing the opening but their use has not been entirely satisfactory, since they tend to reduce production by increasing the time required for the charging and discharging operations. In the operation of most sugar centrifugals, covers have not been employed at all since the output of sugar per centrifugal-for a given period of time was markedly reduced with manually operated covers. The amount of Work for the operation required to control the opening and closing of the cover lengthened the time involved in the operating cycle of the centrifugal appreciably, resulting in a considerably lower output.

In accordance with this inventio the hea en 55 1.

gal is conserved by closing the opening of the centrifugal with a cover which is controlled in accordance with the speed at which the centrifugal rotates. When the centrifugal is rotated at a low speed to permit the introduction of the sugar to heat the sugar bearing material.

bearing material and the discharging of the dried sugar therefrom, the cover is open. When the centrifugal operates .at the high speed, the cover is closed. No time interval is required for the operation of the cover independent of the time involved in the other necessary operations of the centrifugal. The heat energy resulting from the operation of the centrifugal at high speed serves Further, this heat energy together with that-imparted to the sugar bearing material before centrifuging is conserved and is not dissipated by the air currents which would flow through the opening if the centrifugal were not covered.

In a specific embodiment, the cover for the opening of a centrifugal machine is opened when the machine is operating at a low speed to introduce the sugar bearing materials or to Withdraw the sugar therefrom and closed automatically when the machine is operating at high speed which prevails during the extraction of the sugar from the material. The closing and opening of the. cover maybe responsive to these two conditions or be controlled by. changes in the speed of the mechanism employed for driving the centrifugal. Preferably, a pair of covers open and close the opening. These covers may be actuated by a system of bars controlled by a piston and spring. A cover for the closing of the opening in the bottom of the centrifugal may also be automatically controlled in a similar manner.

A more comprehensive understanding of this invention isobtained by reference to the accompanying drawings in which:

Fig. 1 shows top covers of a centrifugal in accordance with this invention and their controlling mechanism, partly in plan and partly in circuit schematic form;

Fig. 2 is a front elevation of a centrifugal,

partly in section, including the top covers and part of the actuating mechanism shown in Fig. 1;

Fig. 3 is a front elevation of a portion of a centrifugal, partly in section, and including a bottom cover together with its actuating mechanism;

Fig. 4 shows an alternative form of control of the covers of this invention from that shown in The same numbers in the various views represent identical apparatus. In Figs. land 2, a fixed casing encloses a centrifugal basket 35 suspended therein and rotated through a shaft 4 by a motor 42 which is enclosed in housing 36. The motor and housing are supported by a superstructure, not shown, from which the shaft 4 and centrifugal-basket 35 are suspended so that the centrifugal-may rotate freely within the casing. Two top covers 2 and 3 employed for closing the opening of a centrifugal machine and all of the cooperating mechanism are in the closed position as shown in Figs. 1 and 2 for the high speed condition. For this condition, a manual switch arm 38 is operated to engage a contact 31. Current flows from the left hand side of power source 40 to a parallel circuit. One branch extends through a conductor 44 and the winding of solenoid 20, through conductor 45 to a junction point 41. A second branch extends through a conductor. 46 and high speed winding 4| to the same junction, point 41. Here, the parallel circuits joinand the circuit extends through contact 31, switch arm 38 and conductor 48 to the right hand side of power source 40 This drives the motor 42 at a high speed. The motor inturn rotates shaft 4 and centrifugal 35 at high speed. ..Current flowing through thewindingofsolenoid 20 actuates a solenoid shaft 2 against thev pressure exerted downward by a spring 22, into its upper position asshown. The spring 22 is retained at its upper end against ,a valve cover. 25which is screwed to a valve body24. At its lower end; valve rod 2| issecured to a piston 23 which is conditioned tomoveup and down within a hollow chamber 3| in the valve body 24; under the influence of current insolenoidwinding 20 and the pressure exerted by spring 22 respectively.

When the piston. 231s in its .upper position, asshown, air under pressure, from a source not shown, is supplied .through a tube IS, a passage 49 in valvebody 24, a notch'50 in piston 23, a channel, 5| and a tube l8 connected to a chamber 52 in a cylinder l6. The air pressure in chamber 52 operating againsta piston maintains the piston IT in its right hand position as shown. The piston is s in, turn connected through a rod 32, a coupling 53 and pin H to a flat plate 29 which is rigidly held to a bar 5. Bar 5 is fixedly attached at its lower end to the cover 3 by means of bolts 28. At its upper end, bar 5 is conditioned to rotate in a horizontal plane about pivot 8,1which is rigidly attached to a fixed plate 54. The cylinder I6 is rigidly secured through a bar 56 and apin l3 to a plate 60 which is fixed in position by means notshownJ A spring I5 is connectedat'its left hand end to the fixed plate 60 by' means of a pin l4 and at its right end it is'connected through a hole drilled in the fiat plate 29 to the bar'5. As shown, for the high speed position, the spring I 5 is distended, tending to open the covers which are held in position and prevented from opening by the pressure of the air against the piston H with bar 5 in a horizontal plane about its cen ter 8 to its extreme right hand position, sliding over the top surface of casing to close the left hand portion of the circular opening in the circular opening over the centrifugal.

the bar 5 also controls the operating of cover 2, simultaneously with the actuation of cover 3. Cover 2 is actuated to close the right hand portion of the circular opening in the following manner. As bar 5 is actuated to the right, it moves a bar 6, which is pivoted to the bar through pin 9. Bar 6 is pivoted in turn through pin 51 to the upper end of a bell crank lever I. The bell crank lever 1 is pivoted through a pin III which is rigidly fixed in the top of casing I. At its lower end, bell crank lever l is bolted by means of bolts 21 to the right hand cover 2. As bar 6 is actuated to the right, it rotates the upper end of the bell crank lever 1 to the right about its pivot III, in turn operating cover 2 toward the left. The cover 2 slides also in a horizontal plane over the top surface of the casingl to close the right hand portion of the Two flat bars 58 and 59 are bolted to the cover 2. These bars serve to cover any opening which may exist in the joint between adjacent edges of the covers 2 and 3 when they are closed. The covers 2 and 3 together with the bars 58 and 59 effectively cover the opening in the casing I over the centrifugal and substantially prevent the flow of air throughthe top opening.

When the speed of the centrifugal is to be reduced for the loading or. unloading operation, the switch arm 38 is actuated to engage a contact 39. flTheicircuit through the high speed winding 4| of the motor 43 and the'circuit through the winding of the solenoid coil 26, both of which were heretofore traced through contact 31, are broken when the switch arm 38 ductor 46, a coil 43, contact 39, switch arm 38 and a conductor 48, to the right hand side of power source 40. As aresult, the low speed winding of motor 42 is energized. The motor is operated at low speed, in turn imparting a low speed through shaft 4 to the centrifugal 35.

When the solenoid 20 is deenergized, spring 22, operating against valve cover 25, is effective to force solenoid shaft 2| and piston 23 connected thereto downward. Notch in piston 23 is thus moved downward out of engagement with channel 49 in valve body 24, cutting off the supply of air under pressure to chamber. 52 in cylinder l6. With the piston 23 in the lower position, the notch 50 engages channels 5|, and,

in valve body 24, providing a means by which the air under pressure in chamber 52 may escape into the atmosphere. This may be traced as follows: from chamber 52, through tube I8,

channel 5| in body 24, notch 50 in piston 23,

channel 55 in body' 24 and a tube 26 to the atmosphere.

When the air pressure in chamber 52 is reduced, the Piston I1 and bar 5 are actuated to the left by the tension in spring IS. The cover 2 rotates to the right about pivot was a center,

sliding over the'top surface of casing With cover 3 actuated to the left, and cover 2 actuated to the right, the opening over the centrifugal is uncovered for the loading or unloadcasing above the open container. Movement of ing operation.

A- valve disc 33 is normally located in the bottom of the centrifugal basket 35. Fixedly attachedto the disc 33 is an eyelet bolt 64 by means of which the disc may be removed to withdraw the sugar from the basket in a well known manner. For this purpose, a hook -65 of a chain 34, which is lowered in the centrifugal basket 35 at the time of the removal of the sugar through the bottom, is attached to the eyelet bolt 64 and subsequently hoisted by means of a Windlass, handle or other device, not shown, over a pulley 66 fixedly attached toa support 61. The dotted configuration of the Valve disc 33 and eyelet bolt '64 designated as 33' and 64' respectively in Fig. 2 shows their position when the sugar is removed through the bottom of the basket. Steam'is supplied to the centrifugal by means of a pipe line 30.

Fig. 3 shows an arrangement for removing the sugar through an opening in the bottom of the centrifugal machine and for substantially preventing the flow of air currents through the opening when the machine is operating at high speed. This system operates so that the bottom of the centrifugal is opened when the machine is operated at slow speed, but closed when rotated at high speed. For the high speed condition, air from a solenoid valve, controlled through the speed changing switch as described for the devices shown in Figs. 1 and 2, is admitted through a tube 312 to a hollow chamber 3l3 in a cylinder 3. The air actuates a piston 3| of the cylinder 3| I to the right against the compression of a spring 309 which is confined between the right hand surface of the piston and an abutment M4 at the right hand end of the cylinder. The piston and a rod 3| 5, integral therewith, communicate a right hand motion through a pin 3|! to a rod 306. The rod 306 is connected through a pin 305 to a right angle arm 304 which is integral with a door 302. Door 302 is a flat circular disc having the arm 304 welded in the middle thereto at right angles to the surface thereof. The base of arm 304 adjacent to the disc is pivoted to a fixed horizontal shaft3 I'6. The cover has a limited rotary motion about said shaft in response to the reciprocal action of the piston. Two positions of the cover and connecting linkage are shown. The position indicated by solid lines is the extreme right hand position of all of the moving parts. It corresponds to the high speed condition of the motor and centrifugal. For this condition, the cover is closed as indicated. The position shown in dotted lines of the door 302', arm 304 and rod 306' indicates an intermediate position assumed by the cover as the piston and linkage move to the left under the influence of spring 309. As the air under pressure is evacuated from the chamber 3l3, in the manner heretofore described, the cover is gradually opened so that the centrifugal may be discharged.

Fig. 4 shows an alternative embodiment for the manual switch 38 of Fig. 1 for controlling the operation of the solenoid Valve in response to changes in driving speed. Instead of employing manual switch 38 to control the solenoid 20 of Fig. 1 to operate the covers 2 and 3 of Fig. 1, or the door 302 of Fig. 3, the solenoid may be independently controlled automatically by the centrifugal arrangement shown in Fig. 4. A spring 401 is attached to the shaft 4 by means of screws 408. To the free end of the spring 401 is fastened a Weighted sphere 40l. As the shaft 4 is rotated, the spring 401 is actuated by centrifugal force so. that the free end tends to move from the shaft. .A contact 402, mounted on the spring 401, engages a fixed annular contact 403 moimted in a fixed housing or guard 404. The annular contact 403 is so disposed in the housing 404'that when the spring 401 is extended in its extreme outward position due to centrifugalzforce, the contact 402 engages the annular contact 403 continuously and regardless of the position of the contact 402 with relation to the fixed housing or .guard 404. The housing or guard covers the shaft about the rotating device and is held in position by meansnot shown. The fixed end of the spring is connected internally by means not shown to a commutator 406 which engages a brush 405. When the speed of rotation of the shaft is 'sufiiciently high, contacts 402 and 403 close, completing a circuit through power source 409 to energize the solenoid winding 20 as shown in Fig. 1, and the covers close. When the speed is reduced, the contacts 402 and 403 open, deenergizing the solenoid winding, and the covers open.-

While preferred embodiments of this invention have been illustrated and described, various modifications may bemade therein without departing from the scope of the appended claims.

What is claimed is:

l. A centrifugal separator comprising a casing, a rotatable basket within said casing, said casing having an opening therein affording access to said basket, a cover for said opening, driving means for rotating said basket at high speed, a controller for engaging and disengaging the high speed drive, a power-operated device for positioning said cover and means connected to said power-operated device and responsive to the positioning of said controller to high speed drive for initiating the closing of said cover by said device, said last-mentioned means being responsive to the positioning of said controller to disengage the high speed drive for initiating the opening of said cover by said device.

2. A centrifugal separator for the extraction of sugar from sugar magma or the like comprising a casing, a rotatable basket within said casing, said casing having an opening therein to permit loading and unloading of said basket, a removable cover for said opening, a power-operated device for positioning said cover, driving means for rotating said basket at high speed, means operatively connected to said power-operated device and responsive to the high speed operation of said driving means for initiating the closing of said cover by said device, and means responsive to the deceleration of said driving means for initiating the opening of said cover by said device.

3. A centrifugal machine for the separation of sugar from sugar bearing materials comprising a rotatable basket, a casing enclosing said basket and having an opening for permitting loading and unloading of said basket, a cover for said opening, a power mechanism for opening and closing said cover, driving means for rotating said basket, means for controlling the speed of operation of said driving means, said control means being operable to one condition to effect high speed driving of said basket, said control means being operable also to another condition to effect lowspeed driving of said basket, means operatively connected to said power mechanism and actuated in response to operation of said control means to said one condition for initiating automatic closing of said cover by said power mechanism, and means ac tuated in response to operation of said control means to said other condition for initiating antomatic opening of said cover by said power mechanism, whereby said basket is automatically enclosed during high speed operation to preclude escape of heat therefrom and injection of foreign matter by air currents otherwise prevailing. V

'4. A centrifugal machine for theseparation of sugar from sugar bearing materials comprising a rotatable basket, a casing enclosingsaid basket and having an opening therein for permitting loading and unloading of said basket, a cover for said opening, a power-operated device controllable to open and close said cover,adriving means for rotating said basket, meansfor controlling the speed-of operation of said driving means, said control means being operable to one condition to effect-high speed driving of said basket, said control means being operable also to another condition, means controlled by the speed of said driving means and actuated in'response to the attainment of a predetermined speed following operation'of said control means to said one condition, means responsive to actu- 25 ation of said controlled means and operatively connected to said device for initiating automatic closing of "saidcover byv said device, and means operatively connected to said device and responsive to the attainment or a predetermined speed following operation of said control means to said other condition for initiating automatic openingof said cover by'said'device." I

I 5. A- centrifugalmachine for'the separation of sugar fromsugar magma, or the like, comprising a rotatable basket'for containing the. material to be centrifuged, a casing enclosing said basket and having' an opening therein for affording access to said basket, a cover for said opening, driving 'means' for rotating said basket, said driving means being operable at either of two substantiallydifierent speeds, means responsive to the operation of said driving meansat the higherof said speeds, cover closing means connected to beactuated by'said responsive means for closing said cover over said opening, means responsive to the operation of said driving means at the lower of said speeds, and cover openingmeans connected-to be actuated y said last-mentioned means'for removing said cover from said opening.

- "WCHARLES A. oLco' 'r.

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