US3530875A - Decanting apparatus - Google Patents

Decanting apparatus Download PDF

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Publication number
US3530875A
US3530875A US3530875DA US3530875A US 3530875 A US3530875 A US 3530875A US 3530875D A US3530875D A US 3530875DA US 3530875 A US3530875 A US 3530875A
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US
United States
Prior art keywords
suction
fluid
sensor
floc
supernatant
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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English (en)
Inventor
Arthur L Carter
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Eastman Kodak Co
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Eastman Kodak Co
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Filing date
Publication date
Application filed by Eastman Kodak Co filed Critical Eastman Kodak Co
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Publication of US3530875A publication Critical patent/US3530875A/en
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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D9/00—Level control, e.g. controlling quantity of material stored in vessel
    • G05D9/12—Level control, e.g. controlling quantity of material stored in vessel characterised by the use of electric means
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/2931—Diverse fluid containing pressure systems
    • Y10T137/3003—Fluid separating traps or vents
    • Y10T137/3006—Liquids separated from liquid
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/8593—Systems
    • Y10T137/86236—Tank with movable or adjustable outlet or overflow pipe

Definitions

  • the invention is especially useful for extracting automatically a particular fluid which is sandwiched between two other fluids within a container.
  • Most prior art decanting and related arrangements are characterized by an automatic control which is slaved, say, to maintain a liquid interface between a pair of immiscible liquids (e.g. U.S. Pat. Nos. 2,985,305 and 3,275,565); or slaved to maintain a predetermined mix of fluids by controllably decanting one of such fluids (e.g. U.S. Pat. No. 2,946,443).
  • a typical environment for the invention is in a process that requires a certain liquid to be drawn from a container, such liquid having had a sludge or the like precipitated from it, and a scum or a foam formed upon it.
  • Liquid-interface controllers are not practical in the environment indicated because rather than maintain'a liquid-interface, the intent in question is to eliminate interfaces.
  • Liquidmix controllers are also not practical because there are no mixes here to be maintained but, rather, a certain liquid is to be drawn from a certain mix ofliquids.
  • the invention employs for decanting purposes a suction and a servovalve and motor, the valve and motor operating respectively to actuate and to position the suction.
  • the suction mounts two sensors, one near the mouth of the suction, and the other back a bit from the suction mouth: the former sensor detects the presence of precipitated floc in the liquid to be drawn off; and the latter sensor detects, in this case, the liquid itself.
  • a suction 20 is positionable relative to the scum, supernatant fluid, and sludge by means of a servo 22. And the suction 20 includes a normally closed valve 24 the opening of which permits fluid to be drawn off via the mouth 26 of the suction 20.
  • a sensor 28 locates at the mouth 26 of the suction 20 and serves to detect a given characteristic of the supernatant fluid 12. In this form of the invention, the sensor 28 serves to indicate the presence of floc 16 in the supernatant fluid 12.
  • the sensor 28 may take a variety .of forms depending on the particular adaptation of, and the environment for, the invention. In the arrangement indicated, the floc I6 (and scum 18) is reflective of light at a certain frequency and, thus, a sensor of the form shown in FIG. 2 has proved quite useful.
  • an encased lamp 30 is periodically excited by a pulser 32, the lamp 30 beaming pulses of light Ithrough an aperture 34.'Light reflected, say off floc l4, falls upon ganged photocells 36 to produce a signal indicating the presence of floc. If preferred, the sensor arrangement of FIG.
  • a NOT circuit as is well known, produces an output signal so long as it, itself, does not receive an input signal, and vice versa. Therefore, in the absence of a floc-indicative signal from the sensor 28, the NOT circuit 38 produces an output signal and applies such signal to open the suction valve 24. So too, provided a relay-actuable switch is set to its upper position, the servo 22 has the NOT circuit sludge, the suction drawing off'the sandwiched liquid during such settling offloc.
  • An object of the invention is to provide improved apparatus for decanting fluids.
  • Another object of the invention is to provide apparatus for decanting a particular fluid, or fluids, from a plurality offluids.
  • Another object of the invention is to provide apparatus for decanting a fluid (or fluids) which is (are) sandwiched between other'fluids.
  • Another object of the invention is to provide improved apparatus for rapidly decanting a supernatant without drawing offany floc precipitated from such supernatant.
  • FIG. I is a schematic diagram, in block form, illustrating a presently preferred embodiment ofthe invention.
  • the switch 40 is actuated by means of a self-holding relay 42, the self-holding contacts of which are indicated at 44.
  • the scum 18 which floats atop the supernatant fluid 12 is electrically nonconductive; and the supernatant fluid I2 is electrically conductive.
  • a fluid sensor 46 which may in the arrangement indicated he a pair. of contacts which are electrically short-circuited when in the supernatant fluid 12, is mounted upon the suction 20, such fluid sensor being disposed behind the floc sensor 28 as the suction moves into the supernatant fluid 12. Therefore, whenever the fluid sensor 46 first actuates, the floc sensor 28 at that time must, of necessity, be immersed within the supernatant fluid 12. (If, in the arrangement of FIG. 1, the scum 18 were to have been electrically,
  • the fluid sensor 46 could still have been employed effectively; however, with such the case, the sensor46 would have to be displaced from the sensor 28 by a distance at least as great as the depth of the scum 18, thereby assuring that the suction mouth 26 will'be within the supernatant fluid 12 at the instant that the sensor 46 first actuates.)
  • the fluid sensor 46 output signal is applied to actuate the self-holding relay 42 to place the servo 22 under the control of the floc sensor 28.
  • a power supply 48 is arranged to actuate the servo 22 via the switch 40 when such switch is in its lower position.
  • the power supply 48 also keeps the relay 42 energized once the sensor 46 gets immersed in the supernatant fluid 12. And for efficient operation of the embodiment as in FIG. I, the suction 20 is capable of drawing off fluid at a ratefaster than the servo 22 can position the suction in the supernatant fluid 12, this being to assure that the mouth 26 of the suction 20 is lowered no faster than the suction can draw off the supernatant fluid l2.
  • the power supply 48 is energized by closing its switch, thereby applying, in open-loop fashion, a signal to drive the servo 22.
  • the sensor 28 produces an output signal, the NOT circuit thereby allowing the suction valve 24 to remain closed.
  • the servo 22 continues to lower the suction 20 until the sensor 46 dips into the supernatant fluid 12, at which time the open-loop servo drive is ended. That is, the sensor 46 energizes the self-holding relay 42 so that the NOT circuit 38 operates the valve 24 and the servo 22.
  • the suction valves opens and, as the supernatant fluid 12 is drawn off, the servo 22 lowers the suction 20 toward the sludge 14. Eventually, when all of the floc has settled as sludge, the supernatant fluid 12 will be completely drawn off, leaving within the vessel only the scum 18 and the sludge 14.
  • FIG. 1 may be modified slightly as in FIG. 3 to provide a faster operating control, and greater assurance that sludge and scum will not be drawn off.
  • a typical timer useful with the invention would be a digital counter which is set to a reference count, such counter being cooperative with a gate circuit that applies clock pulses to such counter for the duration of the sensor 29 output signal.
  • the clock count reaches the reference count, the counter produces an output signal.
  • the NOT circuit 38 applies its output signal to clear the timer and ready the timer to measure the duration of the next floc indicative signal from the sensor 29.
  • the fluid sensor 46 output signal is applied to a relay 42 which, in this embodiment, is not of the self-holding variety, although the relay 42' is arranged to be held energized by means of the holding contacts 52 of the relay 50.
  • the relay 42' operates ganged switches 40'(a,l1). And for an understanding of how the switches 40'(a,b), in conjunction with the other elements of FIG. 3, operate -to control the quick and exclusive decanting of supernatant fluid, the following description is provided: With the suction 20' supported above a fluid container such as the vessel 10, the switch of the power supply 48 is closed. Immediately the servo 22 starts to lower the suction 20', the valve 24 being in its normally closed state (switches 40' a,b, in their respective lower positions).
  • the relay 42 actuates to place the servo 22 and valve 24 under the control of the sensor 29 and the NOT circuit 38 (switches 40' a,b, in their respective upper positions). Since the floc sensor 29 is below the sensor 28, any time that the sensor 29 sees no floc, the sensor 28 even more assuredly sees no floc. Therefore, during the time that the sensor 29 and NOT circuit 38 control the sucking operation, the supernatant fluid 12 which is drawn off is necessarily considerably free of floc.
  • the timer 54 measures the duration that such floc is seen and, provided that the floc is settling fast enough, the timer 54 will be cleared before the self-holding relay 50 can be actuated, whereby sucking will be resumed.
  • the reference time which is set into the timer 54 is of a duration long enough to permit the suction to follow the floc as it settles.
  • the suction 20 lowers enough to cause the floc sensor 29 to become buried in the sludge 14, at which time the NOT circuit 38 ceases to produce an output signal, i.e. the floc sensor 29 produces a steady output signal. Since the duration of the floc sensor 29 output signal is at this time longer than the preset reference time, the timer 54 ultimately applies an output signal to the self-holding relay 50 to switch control of the servo 22 and valve 24 to the sensor 28.
  • the fluid sensor 46 is effectively disarmed, the relay 42 being pulled in by the steady application thereto of the power supply signal via the switch 52.
  • the fluid sensor 46 is disarmed because, as the supernatant fluid 12 is drawn off, the fluid sensor eventually gets pulled out of fluid and, attendantly, absent such disarming, the fluid sensor would prematurely stop the decanting process before all of the supernatant fluid is withdrawn.
  • Means not shown and forming no part of this invention may be provided with the apparatus of FIGS. 1 and 3 to raise the suction (20, 20) after the sucking operation has been completed.
  • Apparatus for use in drawing off a fluid comprising:
  • valve means cooperative with said suction and responsive to the output of said sensor means
  • motor means cooperative with said suction and responsive to the output of said sensor means to position the mouth of said suction within said fluid.
  • a system for so decanting a supernatant from a plurality of. fluids, one of which fluids is largely a precipitate of said fluid to be decanted, that substantially none of said precipitate is decanted with said supernatant comprising:
  • Apparatus for use in decanting a particular fluid from at least two layers of fluids which apparatus comprises:
  • a. suction means having an inlet portion
  • first sensing means responsive to a characteristic of the fluid that is to be decanted, said first sensing means being adapted for positioning with, and disposed proximate, the inlet portion of said suction means; and second sensing means responsive to a charateristic of fluid and being also positionable with said suction means inlet portion, being however disposed behind said first sensing means in the direction of travel of said suction means inlet portion when said inlet portion moves through said fluid layer which is not to be decanted and into said fluidwhich is to be decanted; and
  • said leading sensor being disposed ahead of said trailing sensor in the said direction of travel of said suction means, and wherein said apparatus includes means for selectively placing said motor means under the control of said leading sensor until that sensor senses the said characteristic of said sandwiched fluid for a time longer than a certain predetermined duration.
  • leading and trailing sensors are each adapted to transmit and receive radiant energy reflected off floc within said sandwiched fluid; and wherein said second sensing means is adapted to produce a signal substantially at the moment that said second sensing means is wetted by fluid.
  • the apparatus of claim 6 including means operative in conjunction with said leading sensor for slaving said second sensing means to the interface between said sandwiched fluid and the sandwiching fluid through which said suction means moves into said sandwiched fluid.
  • the apparatus of claim 7 including means for periodically pulsing said sensors.
  • suction means is provided with a mouth which is turned away from its direction of travel while moving into said sandwiched fluid.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Removal Of Floating Material (AREA)
  • Physical Water Treatments (AREA)
  • External Artificial Organs (AREA)
  • Control Of Non-Electrical Variables (AREA)
  • Sampling And Sample Adjustment (AREA)
US3530875D 1968-11-15 1968-11-15 Decanting apparatus Expired - Lifetime US3530875A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US77623368A 1968-11-15 1968-11-15

Publications (1)

Publication Number Publication Date
US3530875A true US3530875A (en) 1970-09-29

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Family Applications (1)

Application Number Title Priority Date Filing Date
US3530875D Expired - Lifetime US3530875A (en) 1968-11-15 1968-11-15 Decanting apparatus

Country Status (6)

Country Link
US (1) US3530875A (enExample)
BE (1) BE741747A (enExample)
BR (1) BR6914130D0 (enExample)
DE (1) DE1957306B2 (enExample)
FR (1) FR2023389A1 (enExample)
GB (1) GB1290550A (enExample)

Also Published As

Publication number Publication date
FR2023389A1 (enExample) 1970-08-21
DE1957306A1 (de) 1970-06-25
GB1290550A (enExample) 1972-09-27
BE741747A (enExample) 1970-04-16
BR6914130D0 (pt) 1973-06-14
DE1957306B2 (de) 1972-11-02

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