US1795179A - Centrifugal drier - Google Patents

Description

March 3, 1931. c, OLCOTT 1 1,795,179

GENTRIFUGAL DRIER Filed Dec. 27, 1927 2 Sheets-Sheet 1 INVENTOR CHA R LESAUL COTT Has ATTORNEYS March 1 C A. OLCOTT 1,795,179

GENTRIFUG'AL DRIER Filed Dec. 27, 1927 2 SheetsSheet -INVENTOR & EHARLBEYS AOLCOTT H IS ATTORNEYS Patented Mar. 3, 1931 UNITED STATES CHARLES A. OLCOTT, OF NEW YORK, N. Y.,

ASSIGNOR TO S. S. HEPWORTH COMPANY,

OF NEW YORK, N. Y., A CORPORATION OF NEW YORK GEN! RIFUGAL DRIER Application filed December 27, 1927. Serial No. 242,893.

My invention relatesto centrifugal driers, and particularly to driers of the type to effect the separation of solids from liquors in which they are contained. Driers of this type are extensively used in the sugar industry for the separation of sugar crystals from their mother liquor, and while my invention is applicable to other industries its general utility will be clear from an explanation of its application to the recovery of sugar from its mother liquor.

This liquor is a concentrate holding in suspension the sugar crystals which it is desired to separate. While the liquor, prior to its concentration, is purified to eliminate undesired constituents as far as possible, it is impossible to accomplish this completely. Moreover it is impossible to concentrate the purified liquor as completely as might be desired, since such concentration if carried too far results in excessive precipitation of the impurities, and these contaminate and lower the market value of the sugar separated from the mother liquor. It is therefore common practice to concentrate the liquor as far as practical without effecting the precipitation of the undesired impurities followed by centrifugal separation of the substantially pure sugar crystals from this liquor, thereafter subjecting this liquor to further treatment for the recovery of a lower grade product.

As an incident to the centrifugal separation of the pure crystals fromthe liquor, it

is customary to follow the spinning off of theliquor by a washing step to remove the last traces of the liquor from the crystals before they are discharged from the basket. In brief, after a charge of liquor has been passed through the centrifugal, and while the separated sugar crystals are still walled up in the basket, the supply of mother liquor is shut off and a supply of pure wash water is delivered to the centrifugal. Passing through the walled up sugar crystals, this wash water removes the residual mother liquor carried by the crystals and leaves the latter clean. Incidentally, however, the wash water dissolves a certain percentage of the sugar crystals themselves, and would incentrated without precipitation of the impurities, and a relatively high grade product may be derived from it as distinguished from that which is derived from the residual mother liquor. .Therefore it is highly desirable that the wash liquor and the residual mother liquor be separately recovered from the centrifugal drier, so that they may be separately subjected to appropriate after treatment.

My invention contemplates the automatic separation of the wash water from the residual mother liquor as they successively run off from the centrifugal drier. My invention also contemplates appropriate apparatus for accomplishing this.

The application of my invention to other processes than the recovery of sugar from mother liquor, will readily occur to those dealing with the subject, as well as appropriate modifications of the apparatus to such other industries to which my invention 1s applied.

In the accompanying drawings- Fig. 1 is a broken side elevation of a sugar centrifugal in which my invention may be carried out;

Fig. 2 is a section on the line 2-2, Fig. 1;

Fig. 3 is a broken side elevation of the apparatus shown in Fig. 1 with the parts indicated in the position which they occupy during the washing step; and

Fig. 4 is a section on the line 44, Fig. 3.

It will be understood that the accompanying drawings illustrate but a single illustrative embodiment of apparatus suitable for carrying out my invention, and that the latter may be practiced in various ways while still embodying my underlying thoughts. Referring to the drawings, however, I have shown conventionally a centrifugal basket 15 suspended on a spindle 16 and rotating within a surrounding casing 17, the lower portion of 1 piston 25.

which forms a gutter 18 through Which the mother liquid and wash water pass to a spout 19. The latter delivers to a deflector 20 pivoted at 21, by which the fluid passing through the spout 19 is discharged into either trough 22 or trough 23.

The deflector 20 is actuated either manually by a hand lever 24 fast on the axis 21, or by a piston 25 working in cylinder 26, the piston rod 27 having a lost motion engagement at 28 with the hand lever 24.

In Fig. 1 I have shown the basket 15 with a charge of sugar 29 walled up against the periphery of the screen. During the operation of the walling up of the sugar, the deflector 20 is in the position indicated so that the mother liquor discharging through the spout 19 from gutter 18 is deflected into the trough 22. When the charge in the basket is complete wash water is then applied through the nozzle 30 as indicated in Fig. 3. The nozzle 30 is at the end of a pressure line 31 through which the Wash water is delivered, this line being controlled by an appropriate valve 32, which is here shown as manually operated, although it may be automatically opened if preferred. Connected to the line 31 beyond the valve 32 is a branch line 33 which leads to one end of the cylinder 26 behind the Consequently when the valve 32 is open and the pressure liquid flows to the nozzle 30, it also flows through the branch line 33 to the cylinder 26 and forces the piston 25 to the left, thus shifting the deflector 20 to the position indicated in Fig. 3. As a consequence the wash water now flowing.

through the gutter 18 and spout 19 is deflected into the trough 23 and is thus separately recovered from the mother liquor which has been previously received from the trough 22. This automatic operation of the deflector incident to the application of the wash water to the walled up sugar, is a feature of considerable practical value, sinceit leaves no operation to be performedor neglected to be performed-by the attendant.

When the sugar has been discharged from the basket the lever 24 is then returned to its original position. This operation forces the water which is behind the piston 25 through the branch line 33 and nozzle 30, thus washing out the apertures in the basket before a fresh charge of mother liquor is introduced. This feature also has its advantage from a practical standpoint.

While I have shown the deflector operated by a piston connected in the wash water pressure line, it will be understood that this simple arrangement may be modified in many ways, for example if the wash water were applied by a pneumatic pressure line the actuating connection for the piston could be to the pneumatic pressure line. Similarly if an electric operation were desired, a pressure operated switch could be applied to'the nozzle 30, the

switch closing the circuit of a solenoid, which will operate the deflector 20. These are but suggestions of various ways in which the same thought may be carried out. With thev understanding therefore that when applied, for establishing an off-flow path different from that followed by the liquor on its escape from the solids.

2. An apparatus for deriving and washing solids from mother liquor and separately recovering the wash and mother liquors, comprising means to separate the solids and mother liquor by centrifugal force, means to spray a washing liquid on the solids thus separated, in combination with means, controlled by the pressure of the washing liquid to divert automatically the wash liquor into a run off path different from that followed by the mother liquor.

3. An apparatus for deriving and washing solids from mother liquor and separately recovering the wash and mother liquors, comprising rotating means to collect the solids and drive off the mother liquor, means tointroduce, into said rotating means a washing liquid wherebythe solids are washed, in combination with means, acting automatically in response to the introduction of said washing liquid, to divert the wash liquor to a run off path different from that followed by the mother liquor.

4. In a centrifugal drier a rotary basket screen a plurality of off-flow channels for fluids discharged from the screen, a deflector for shifting the discharge from one channel to another, a pressure line for applying liquor to the material contained within the basket, and pressure responsive means for automatically actuating the deflector on the application of said liquor to the material con tained within the basket.

5. In a centrifugal drier, a rotary basket screen, a plurality of off-flow channels for fluids discharged from the screen, a deflector for shifting the discharge from one channel to another, a pressure line for applying liquor to the material contained within the basket, and an operating connection between said pressure line and deflector for automatically actuating the latter when the pressure line is open.

6. In a centrifugal drier, a rotary basket screen, a plurality of off-flow channels for fluids discharged from the screen, a deflector for shifting the discharge from one channel to another, a [pressure line for applying liquor to the material contained within the basket, and a hydraulic operating connection between said pressure line and deflector for automatically actuating the latter when the pressure line is open.

7. In a centrifugal drier, a rotary basket screen, a plurality of off-flow channels for fluids discharged from the screen, a deflector for shifting the discharge from one channel to another, a pressure line for applying liquor to the material contained within the basket, and an operating connection between said pressure line and deflector for automatically actuating. the latter when the pressure line is open, together with means for manually shifting the deflector in opposite direction,

8. In a centrifugal drier, a rotary basket screen, a collecting gutter below the same with a discharge spout, a plurality of ofi'- flow channels for the fluids discharge from the spout, and means of applying a washing fluid to material contained in the screen in combination with an adjustable deflector operated by means of the washing fluid pres sure for shifting the discharge from one channel to another.

9. In a centrifugal drier, a rotary basket screen, a valved water pipe with nozzle therein, a branch pipe connected to said water pipe and having a cylinder and piston on said branch to wash out the basket before a fresh charge is introduced therein.

10. In a centrifugal drier, a rotary basket screen, a plurality of off-flow channels for fluids discharged from the screen, and a deflector for shifting the discharge from one channel to another, in combination with a water supply pipe with nozzle extending into the screen, a branch pipe connected at one end to said water pipe, a cylinder connected to the other end of the branch, and a piston in said cylinder operatively connected with the deflector.

In testimony whereof I have signed my name to this specification.

CHARLES A. OLCOTT.

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