Apparatus and method for positioning the point of droplet formation in the jetting fluid of an electrostatic sorting device

In 'gOZHéti. The present invention relates to trailing called electrostatic flow sorting and more particularly the sorteringsanordninger adapted to sense the presence and / or nature of particles in 1:05 la.minær stream and to selectively sort those particles by 'to break the current in a plurality of discrete droplets and sorting those droplets containing such preselected particles. Such sort known for use in sorting and analyzing cellular composition of given biological samples, eg.

10 by counting / analysis of cell types for a given blood sample.

In an apparatus of this type is Cutlet automatic laminærstrømmen established in an area where a light scattering, fluorescence or volume measurement is performed. Once a cell of interest has been sensed, an electrode 15 tronic delay enabled timeframe jaødvendig for the cell to cover the distance from the point of cell detection to the point of droplet formation. Droplet formation may be accomplished by vibrating a flow chamber or orifice through which the flow passes, 20 at a rate sufficient to produce droplet formation, usu¬ in strørrelsesorden of about 000 bO cycler per sec. When a cell of interest arrives at the droplet formation point, a charging pulse to be applied to charge the droplet (plus, minus, or neutral), sealer 25 droplet of interest enters a subsequent DC current field, where it can be deflected as desired for collection.

A general overview of this technique is given in "Laser Flow. Microphotometry For Rapid Analysis And Sorting Of Mammalian Cells," Mullaney, et al., Annals New York Academy Of Sciences 30, Vol. 197 »page 17.6-19Q (see especially page l80 and FIG. 3 b). .

Such partikelsortere are also described in U.S. Patent Nos. 3,710 '933 and 3380 ρδ'ί and 4 li-8 718. In these patents are sorting completed in accordance with a selected parameter 35 can be sized, radioactivity quantity, color, fluorescence, light absorption or any property that is able to be transferred to an electrical quantity.

These patents disclose in addition singularly or in two more parameter measurements to perform Iike sorting.

For selective-sorting those droplets containing cells which are determined to be of particular interest depends usu¬ of apparatuses of this type 5 by a flow rate evaluated for the fluid containing a particular cell. This strømningsmeiigdvurderingen is utilized to assess the time between celledetekteringen and drop breakpoint at which selective charging of the droplets to be sorted 'can say ed. As described in U.S. Patent No. 10. 3 '710 933 is such systems usu¬ aligned and adjusted prior to cell measurements. Droplet formation becomes usu¬ specifically controlled by illuminating radiated liquid jet near the flow chamber with a strobe light or equivalentlyskilde. Stroboskoplyset being synchronized flash 15 with respect to the oscillator frequency. Drop Form ^ tion can .. so be considered using et'mikroskop and by varying the voltage and frequency supplied to strømningsforstyrrelses inverter may drop formation can be adjusted for a given nozzle diameter and s.trømningslengde. See U.S. Patent Nos. 3,710,933> 20 column 11, line lk h9.

As described in particular in U.S. Pat. No. 3,710,933, the flow amount by applying known pressure to different reservoirs be evaluated and the cell current is adjusted by varying the relative pressures between the various reservoirs reservoir 25 which is inserted in the stream. Approximate delay between celleavfølingen and droplet formation (which is considered in the abovementioned US patent, and be of the order of l4oo mikrosek.) Can be considered such that a suitable dråpeladnings generator will operate in combination with pulse height analyzer 30 and cell separation logic to charge the selected cells containing droplets for subsequent electrostatic sorting.

A number of factors affect the ability of a given apparatus to selectively sort one or more types of target cells from a continuous cell stream. Also Assuming-35 contents that detekteringsutstyret to identify each cell 'to be sorted is $ 100 accurately the difference in the flow rate, temperature, fluidiumviskositeten and converts embodiment affect the time delay or location 1 ..1 3 of the desired målcelleinneholdende droplets at the breakpoint, which is the point at which a charge pulse must be applied to ensure that the target cell would become electrostatically sorted

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in the following.

5 One of the methods used to adjust such a sorting apparatus' includes driving a below-søkelsesprøve through the apparatus is set or programmed to sort for one or more readily identifiable cell types. According to this procedure! 0 is the delay time manually adjusted until the droplets which are sorted from power is found to contain the expected number of target cells. While this procedure used alone or combination with stroboskopmetoden described above has proved to give partially lucky re-sults 15, the inclined at a certain degree to provide error '. · Especially during periods of extensive use of machinery and / or changing operating conditions, such as foraridring in sample viscosity and / or temperatures.

In U.S. petent no. 3,826,364 is described 1:20 particular sorting method and apparatus wherein a co-sialstrøm is triggered through a vibreringsdyse. Examination (interrogation) of the stream by one or more cell lead means for sensing cells in the stream occurs immediately downstream of the nozzle. In the above-25 mentioned patent, ladepulser applied at specific times for accurate separation of droplets by use of the delay units which are adjusted to provide the necessary time delay to provide movement time of the particles from the point of partikkelspredningsdetektéring.til point 30 where the power is interrupted in drops, ref. otherwise ovénfornevnte patent, column 7> line 22-32.

As stated in said patent, the duration as well as the use time of ladepulsene critical for the separation of at least the droplet containing niåle-35 particle to be sorted. Ref. however also mentioned patent Col. 8, lines 2-6,

As also mentioned in the above U.S. Patent causes a drop fracture from a given current with a charge which is 1 k pL'ci-porsonal and potential between dråpastrømmen and surrounding electrodes or charging surfaces at the time of drop separation from the stream. 'If the droplet breakup of beam current during the transfer time from dråpelad-5 tion pulse, either during the flank or the rear edge of the pulse, an intermediate value between 0 and the desired full charge be assigned måldråpen. In the device of U.S. patent 3,826,364 is on / off transitions with dråpelad-ningspulser synchronized with the droplet formation device 10 hvorve.d charge pulse transitions may be synchronized to forekomme- only between the formation of droplets when the droplets are not separated from the stream. This is made possible by the above arrangement, by providing a variable phase control unit included in the conversion control circuit 15 is adjusted for correct clocking of drop formation with dråpe-- r V \ .; · charge pulse. As described in U.S. Patent Nos. 3,710,933 provide stroboscopic illumination of the stream the ability to regard the current through a suitable microscope, said strobe oskopiske illumination is synchronized with dråpeladnings-20 pulses so that power and more particularly deflected drops may * be illuminated to ensure that the deflected drops contain the desired particles to be sorted.

In recent times, various apparatus and methods have been proposed to clock the use of 25 a charge pulse so that droplets containing the particles to be sorted may be selectively charged. U.S. Patent Nos. 3,963,606 describes a special separating for separating particles in a fluid according to certain particle characteristics.

This device comprises en'innretning adjustment 30 an electrical delay to be equal to the time between emission of particle from a jet forming aperture to the point of fracture. The foregoing patent proposes the use of a movable scale in place of the frosted glass by prior art projekseringsmikroskop, with this scale 35 connected to a potentiometer of an RC oscillator to thereby control the oscillator frequency. A second potentiometer for controlling klokkeoscillatorfrekvensen is coupled to a height adjustment element of the opening, said frequency one.

5 is used to clock delay ^ shifting registers such that the charging pulse may easily be caused to occur at specific times, regardless' jfluktasjonstrykk, velocity, amplitude and frequency of droplet forming generator. See U.S. 5 Patent Nos. 3,963 6o6., Column 2, lines 23-36. The above patent shows a more automated verson of strobe-pro jeksjonsmikroskop technique; described above.

Droplet forming characteristics in a magnified 'flow thus has been considered in connection with the type 10 dye jet printing. By colorant jet printing where discrete ink droplets formed in an ink jet stream are electrostatically directed to form characters on a opptegningsflate, especially attenuation of a bit made to establish uniform droplet formation and charging characteristics. Since the charge given to every 15 given droplet at its breakpoint is proporsonal with its ovfer- wv; · flat area, it is the shape of the .dråpen at break point and the uniform light charge variations may produce erroneous avbøyningskarakteristikker has farvestråletrykkere proposed various systems to provide 1:20 ink jet stream comprising regular shaped and uniformly charged droplets which will provide a predictable nedstrømsavbøyningsoppførsel. These issues are complicated by the tendency of the by-track account current form "satellites" that not only affect the charge applied to previous or subsequent drops, but 25 also changes the volume of these droplets, thereby correspondingly affecting print ingens smoothness.

By farvestrålesprøArting has numerous systems have been proposed for sensing the characteristics of a disturbed color beam current, either above or below the break point 30 to said flow. U.S. Patent Nos. 3 907 ^ -29 describes a method by means for detecting the speed of detecting the droplets formed from a liquid stream. According to this specification, discrete droplets directed between a pair of apertures and a light source which is synchronized stroboscopic 35 ery selected frequency and directed towards the opening. By detecting the time between when a first of the apertures is blocked by a droplet in the stream as is indicated by the light is refracted. * During stroboskoptilføringen and the time when a second of '. 6. the apertures is blocked by another droplet, when the light source is counted, the velocity of the droplets may be measured and a correction of the speed can be, conducted by changing the pressure of the branch flow of fluid, U.S. Patent Nos. "5 July 3 ^ 9627 use is ery ink jet print system one ioneut- charging of drops in which a light source and a photocell located downstream from the break point to a disturbed flow may be used to sense the passage of discrete droplets and time-measuring delayed charges subsequently provided thereto. cf., 10 rest U.S. patent no. 3:07 ^ 9627 column 1, line 18-35 ·

This procedure is performed using the above-described photocell arrangement for counting and synchronizing charges applied as discrete droplets pass a plurality of separate charging stations which respond to coded information 15 fed to each station in synchronism with the passage of each -dråpe;

As described in U.S. Patent No. k Obj 183 is efforts have been made to provide control and 9 formation of the shape of droplets in an ink jet stream by 20 sensing the surface wave profile of the continuous portion of the stream (upstream from the breakpoint) by illuminating the part of the stream with a radiant energy source such as a laser. The surface wave profile produced by illuminating the stream to provide the fundamental and harmonic sequence 25 components thereof and a disturbing drive signal, whose amplitude and relative phase as a function of the sensed frequency components for controlling the formation and shape of droplets. After a description of the advantages and difficulties of controlling avbrytingsgeometrien, especially with regard to the 30 the illumination of satellite formations, describes aforementioned patent the practical desirability of measuring the ink jet stream upstream rather than downstream from the droplet fracture point. ref. otherwise U.S. Pat. 4:00 7:01 ^ ^ 3, column B, line 53 to 68.

35 The above patent describes a system wherein an ink jet manifold having a disruptive means such as a piezoelectric crystal submitting a disturbed color beam current into en.ladningselektrode construction. In. j ·. 7 which is pulsed in a well known manner to selectively apply charge to the droplets. A source of radiant energy, which may be a helium-neon laser rays radiant energy focused on the continuous portion of the jet "network før'1 radiation entering 5 in charge electrode structure". Since color is opaque, a shadow formed which is imaged through a lens on a substrate having a gap thereto. This shadow formed thereby constitute surface wave profile. the beam is a "representation of the respective amplitudes and relative phases of IQ to fundamental and harmonic frequencies, ref. otherwise mentioned U.S. Patent Nos. k 0 ^ 7183, column 6, lines 27-68, column 7, lines 1- 26.

In a preferred embodiment in the aforesaid application, the output signal obtained på.denne way brought to 15 to control the fundamental and harmonic frequencies applied you · -piezoelektriske forstyrrelSesinnrptningen for controlling the droplet formation and shape of droplets produced by the ink jet stream.

Cf., also IBM Technical Disclosure Bulletin 2Q Volume 16, No. 12, May 197 ^, pages 3877-8, entitled "Feedback For Synhronized Pressure Jet Using Optical Sensor", and IBM Technical Disclosure Bulletin, Vol. L6, No. 3, August 1973, page 88o, titled "Phase Detection On Ink Jet Droplets". describing color beam press systems that ask-25 isnt optical sensor ,.

Other writings describing different color beam press sync Inga systern are US Patent Nos. K 025,926, no. B QB5 770, no. 3,953,860, no. 3761 9k1, no. 3,836,912, no. 3,982,251, No. . 3,878,591.

30 Other patents describing particle or flow sorting systems are U.S. Patent Nos. 3 S> bl h 79, no. 3,851,169 and no. 3,910,702 ·.

The present invention provides a novel method and apparatus for precisely establishing and position-35 ering of the break point by a laminar flow of an electrostatic particle sorting apparatus. By accurate control * of the break point in the system, other factors, such as variable surface tension, viscosity, temperatures, etc., as

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8 could otherwise interfere with the accurate charging of particles containing droplets, do not interfere with droplet ladningssynkrnniseringen. [

A new electrostatic particle sorting 5 system is described comprising a flow means for establishing flow of a continuous · particle containing stream comprising at least a particle containing core stream and an enveloping power. An optical transducer is disposed to optically detect pair jQ particles at least at a particle sensor point along the stream. Disturbance device for interrupting power to be achieved in at least a preselected frequency and amplitude to cause the stream to form a termination point (break point) at which the stream becomes a series discrete droplets. For.å intact 15 the relative charge so that selected drops innehpld'er -i det.minste selected particles detected by the optical detection teringsinnretningen is eh synchronizing device disposed consisting of a omhyllingsfølerinnretning for sensing light spreader, quench character stream in an OMPI envelope 2Q feel point subsequent instead of the interference, surface character analysis means for providing an output signal at least reacts selectively of wrap sensing means, and forstyrrelsesarnplitude adjustment mind direction responsive to the surface character analysis means 25 for establishing and maintain breakpoint at of wrap sensor point.

In the preferred embodiment comprises about-hyllingsfølerinnretningen by a radiant energy source focused on the stream to measure the spreader and shutoff of power and 30 more particularly omhyllingsstrømdelen to the stream. Sore.

hyllingsfølerinnretningen thus provides a surface character output signal proporsonalt with overflatekarak harvester to flow. According to the preferred embodiment disturbed laminar flow has been found and to provide in 35 substantially different and distinct output signals when they are sensed above, winds or by their break point.

When comparing real time waveform characteristics with a reference waveform characteristic setting, an error

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9 signal accordingly be obtained by varying the amplitude of the * transducer until the breakpoint is established and maintained at the omhyllingsfølerpunktet. Assuming that a fixed flow rate will consequently a given time delay give 5 precise droplet charging of droplets containing particles in-dentifiserte upstream .sortering.

A primary object of the present invention is to provide an improved electrostatic particle sorting apparatus wherein the breakpoint of a laminar disturbed 10 near the power is established and maintained at a fixed location.

This and other objects of the present invention will be further described in the following.

Oppfinnselsen will now be described by way of preferred embodiments in connection with the character 15 bores, in which: '

Fig. 1 shows a partial block diagram of the preferred embodiment apparatus of the present invention, Fig. 2 shows the waveform of a overflatekarak-ter-output signal produced at break point area to 1:20 laminar flow,

Fig. 3 shows the waveform of the surface character output signal when omhylningsfølerpunktet located below the break point. a disturbed laminar flow, and

Fig. Shows the waveform of overflatekarakterut-. 25 time signal produced when omhyllingsfølerpunktet being placed over the breakpoint to a disturbed laminar flow.

The object of the invention is to use den.sammen with an electrostatic particle sorting apparatus wherein a series of particles suspended in a fluid is 30 introduced into an envelope-stream 12 to provide a laminar flow l4. This stream is then caused to flow through a laminar strømni ngs chamber where an optical detection teringsinnretning detects particles by at least one particle sensor point, and detects which of these particle lean 35 to be sorted from the stream. This optical detec-. ment may use a helium-neon laser focused on the laminar flow 14 inside laminærstrømningskammeret. By. using different photo optic detectors in combination In '10. with different nozzles introduced in kjernéstrømmen can scatter, absorption, fluorescerings- or other characteristics of the particles felt by particle feel point identify the particles in the ensuing be sorted.

5. The particle detector source 16 may be a light source, one lysemmiterende diode, helium neon laser, or laser diode. One or more particle detector receptors 18 may be oriented at one or more positions relative to the stream, depending on particle type and location of energy 10 to be detected. In the event that a particle selected for sorting has been sensed, an appropriate time delay circuit 20 adjusted for triggering the droplet charging circuit 22 will cause the relative charging of the droplet containing the preselected particle precisely at the time when the drop is formed 15 at the break point 26. By According detection ^ by. the desired particle by particle point currents flow through r an opening 28 which is disturbed by a turnover and turnover driver 32 and 3 ^ · respectively. Forstyrrelsesinnrétningen in the disturbed laminærstrømmen J6 increases gradually in size 20 or amplitude due to the surface tension of the liquid radiation. According to;. the preferred embodiment of the present invention interfere disturbance means, which comprises the transducer 32, reacting Driver 3 ^ · and a controlled amplitudeoscillator 38, stream with at least 1:25 preselected frequency and amplitude to cause the stream to form a breakpoint designated 26.

Synchronization device of the present invention comprises a omhyllingsfølerinnretning for sensing said lyssprede- and extinguishing character stream by a • 30 omhyllingsfølerpunkt subsequent disturbance! and for producing a surface character output signal which is pro-porsonalt thereto. As shown in FIG. 1 equivalent of wrap sensor point breakpoint, the breakpoint is automatically maintained at omhyllingsfølerpunktet as described 35 in detail later. Omhyllingsfølerinnretningen consists of an 'envelope detector to 2k, which is a radiant energy source with respect to which omhyllingsstrømdel is substantially translucent. In the preferred embodiment, ι · 11 omhyllingsdetektorkilden be a helium neon laser, a light-emitting diode, a laser diode or a common light source. Omhyllingsdetektorkilden is focused on power. Suitable optics should be provided for focusing radiation energy for 5 stream. A lens assembly comprising two cylindrical lenses has been found to be suitable for this purpose, the 'each of these lenses have their axes oriented perpendicular to the axis of incident light, as well as perpendicular with respect to each other .. It has been found that IQ suitable .to use an fremre.'sylindrisk lens that has a focal length of approximately 6rnm and a rear lens has a focal length of approximately llcm. The preferred envelope detector receptor is a photodiode, but may also be a photomultiplier. By the above identification lenses 15 tending the front lens to focus radiant energy * on stream while the rear linsen.fokuserer incident energy * give the diode. We have found it suitable to benytte- a conventional FC200 Ortho Instruments lens unit for this purpose. This lens assembly, for example. be located approximately 6,3mm from 2Q current and photodiode approximately 25, Amm on the opposite side of the stream after the focal point of the lens device for the photodiode to take up a major portion of the light either scattered or off the power, but not so much light that it occurs one detektormetting.

25 To measure the relative spredningen.og shutoff of flow at omhyllingsdetekteringspunktet is an OMPI envelope detekteringreseptor Ao disposed opposite of the current in a position such that the relative differences in the flow of wrap proliferation will provide proporsonalitetsforskjeller in 3Q departure oinhyllingsdetektorreseptoren, whose output signal represents a overflatekarakterutgangssigual. In the preferred embodiment omhyllingsdetektorreseptoren a photodiode or less preferably a photomultiplier.

Surface grade output is received 35 by a waveform characteristics detector generator 4l which analyzes. lyses surface character of the stream and produces' its own output signal which is compared with the signal of • one referansebølgeformkarakteristikk- innstilingsinnretning A2 12 via an error signal generator 44 to provide an error * signal in the event that the droplet breakpoint is found to be at omhyllingsfølepunktet. This error signal will increase or decrease the amplitude of the disturbance applied to laminar-5 stream using transducer from interference through aforementioned styreamplitudeoscillator 38 and omsettérdriveren 34, In this way, drop breakpoint 26 automatically. igjenanbragt by omhyllingsfølerpunktet and will be maintained in that position even in the case that other factors 10 such as surface tension, viscosity, flow rate, temperature, åpningsdiametar, etc. change during the operation of the apparatus. Yed the preferred embodiment, for a given laminærstrøm should, omhylningsfølepunktet be positioned so that under normal conditions are omsetteramplituden 15 is set to about 30 $ of its maximum amplitude, which 'thereby providing a substantially adjusting the amplitude to' compensate the above mentioned effects.

Fig. 2,3 and 4 show waveforms for laminær- t stream respectively below and above the breakpoint. When 20 monitored by omhyllingsfølerinnretningen precursor real time from left to right, while the amount of light sensed by the hylningsdetektor-receptor increases vertically. Fig. 4 shows a graph of disturbed laminærstrøm 36 when omhylnirg sfølerpunktet is disposed substantially above the breakpoint, and 25 as seen in the curve, the surface character output signal a substantially sinusoidal. The peaks 100 and 102 correspond to relatively thinner portions of disturbed flow, where significantly less parts strålingsenergien'er omitted pmhylningsdetektorkilden 24, is caused to be dispersed, 30 and substantially larger part of the energy is thus received by omhyllingsdetektorreseptoren (receiver) 40 .

Wave troughs 104 and 106 correspond to "bulges" or areas of relatively greater amplitude · in the disturbed flow 36, and causing the corresponding main-35 substantially larger portions of radiation energy from omhyllingsde-, tektorkilden 24 to be scattered and thus not received by omhyllingsdetektormottageren 4o . Fig, 3 shows the surface. character output signal when omhyllingsfølerpunktet disposed in · 1:13 substantially below the breakpoint, the er'når discrete droplets have already been formed, each of the wave troughs 110 and 112 correspond to discrete droplets, and the small wave troughs ll4 and ll6 corresponding to small intermediate "satellites" 5 and the remaining portion of the waveform 1.3) 8 and 120, when peak amounts of light received by omhyllingsdetéktormottageren corresponding to the spaces between droplets (and / or sate zeolite). The unique waveform shown in FIG. 2 is the waveform of one overflatekrakterutgangsignaler when, omhyllingsføler-10 point and rupture point range corresponds. The spaces between the droplets 122,124 and 127 represent times when the maximum amount of light collected by fotodiodeomhyllingsdetektormottagerne 4o. The deepest wave troughs indicated at 128 and 130 and 132 represent maksimale1 bulges with droplets to be formed.

15 Small ribs 134 is as shown in curve danrj ^ ten plaque.

and may be the result of harmonics in turnover rate, or 4 otherwise naturally results from the behavior of the droplet or fracture point if the behavior is not so far been fully understood. When following the buckling, but still connected 2o thereto is ribbon members representing rapid extension of the ends of buckling to a band that has a smaller center than. ends. This band size and geometry blocks only about one half the light as the largest portion of the droplet. This ribbon section has been broken away from previous drops 25 ° S frirmbåndhellingene i'42, L44 and L46 'leads clearly to free air space, such as 124 and 126. between the drops. As seen from the waveform in FIG. 2 are three special stages hell-ihger with considerable amplitude which constitute the waveform at breakpoint. First,; forming negative drops slope l48, April 30, 50 and 152, so -forming positive droplets / band inclines 134, 136 and 158 and finally ends positive ties hellingene1 L42, L44 A, L46. This can be seen in contrast to the slope shown in the waveforms of FIG. 3 and 4 in which regular number of positive and negative slopes are observed.

35 According to the preferred embodiment of the pre- * present invention can also a certain degree of ambient light may be collected by omhyllingsmottagerdetektoren and consequently the * trough 110, 112, 104 and 106 easily flattened, instead of I \ lk being smoothly rounded, which will be waiting if ambient light was excluded from s ^ rstemet. Further it has been found that the breakpoint waveform in Fig. 2 need not be as well defined as shown in the figure, but rather clear breakpoint-5 waveforms may nonetheless be derived even if a slight defocusing of omhyllingsmott.agerkilden er'tillatt, thereby eliminating detection of the small ribs, such as ribs 13A and / or any of the specific details of the band-shape as shown at 136, 138 and 1 ^ 0.

10 As known to those skilled in the art is the small satellites such. indicated at ll4 and ll6 in FIG. 3 extremely unstable, possibly because of their movement in the wake of much larger s £ ERISKA objects and / or other conditions caused by various induced charge-15 readings between adjacent charges. It is theoretically found that the shape of luftstrømmen'rundt large '· spherical * objects will tend and move the satellite droplets either up or down depending on the size, wave length and flow rate of droplet flow .. The waveform shown in FIG. March 20 will accordingly be expected to be produced within approximately three wave lengths bortenfra breakpoint. When of wrap detekteringspunktet is moved down the impact of migration and flow around the sphere will be much more clear and satellites registered as either "fast" or "slow" satellites.

25 In the case eg. that satellite ll6 is "fast" it would tend toward and merge with its previous drop, and consequently it will be seen that space-shifting to drop 110 until it merges with this. Similarly, if satellite ll6 were a "slow" satellite, its posi-tion 30 would tend to change relatively to the drop 112 until it merged and was taken up by the droplet 112, which is the subsequent drop relative to that satellite.

According to the preferred embodiment of-this invention will waveform characteristic detector generator 35 analyze the surface character output signal, etc., to determine if their signal is favorable compared to the reference waveform karakteristikkinnstillings-. signal. While one skilled in the art will see from the I. ί 15 * different waveforms shown in the figures that there are many parameters which can be used to record the waveform of FIG. 2 from those of fig.i 3 and k, it is believed that the technique described in U.S. paterit application no. 68112, filed 5 20th August 1979 "the beste.måten scoring analysis. As described in this application will vedhjelp of dif ferensering surface character output an odd number of peaks corresponding to the three stage bruddpunkt- tops to the substantial amplitude will be produced when about-10 hyllingsfølerpunktet is located at the breakpoint, whereas an even number of such peaks will be produced per. cycle if omhyllingsfølerpunktet is placed either above or below the break point. In both of these latter two cases, 'the error signal generator producing an error signal V 15 for varying the controllable tea amplitudeoscill ^ J; ears and. 'Thus act by reacting Driver 3 ^' '> the converter 32 and the opening 28 to vary forstyrrelsesamplituden disturbed laminar flow 36. This in turn will move the breakpoint disturbed laminar flow until the fracture point 20 a corresponding to omhyllingsfølerpunktet, by whose point no further error signal, and thus no further change in omsetteramplituden need be tilve.iebragt. Assuming a constant flow rate, a fixed time delay provided by the time.

25 delay 20 causes drop charge through dråpeladnings-. circuit 22, so that the drop is charged at the breakpoint may be sorted through the application of an electric field generated by åvbøyningsplatene 200 and 202, so that the desired particles to be selected may be gathered in one of the sample 30 collection vessel 20b, 206 or 208.

Of the above fr.emgår that an extremely simple "·· and effective method and apparatus are disclosed for precisely determining and establishing the breakpoint · eh disturbed laminar flow at a fixed distance from partikkeldektek-35 teringspunktet. Assuming a fixed flow rate, * will exactly fixed time delay accordingly ensure precise droplet charging of droplets containing particles to be * be sorted.

In. in 16 .. It is clear that various changes in the details, feeder compilation and arrangement of parts herein have been described eg shown to explain the invention can be made by those skilled in the art within the spirit and prin-5 principles of the invention as claimed. The expressions "interference" or "interference device" is intended to * include not only mechanical vibration methods to provide diskontnuitet stream, but also discontinuities which are induced by other means such as 10 a switching power surface tension, e.g., by electrical, thermal or optical devices. Likewise, it is meant to include a periodic or aperiodic interference.

15 h 20 25 '30 35 ft t · I. in 17. 1. Electrostatic particle sorting system, characterized in that it consists of a) flow means for establishing the flow of a continuous particle containing stream lish 5 passes at least a particle containing core stream and an enveloping stream, the stream of particles having a particle sensing point defined therealong, b ) particle sensing means for optically detectable ing of the particles at least at the particle sensor point 10 c) disturbance means for disturbing the flow with at least one fordtbestemt frekvensamplitude to the stream to form a breakpoint where the flow is a series of discrete drops, d) droplet charging means for relatively charging (15 of selected droplets as they are formed by bruddpranktet, .and · e) synchronization means for intact the reia-tive charge so that selected droplets contain at least selected particles detected by the optical detection teringsinnretningen, wherein synchronization means consisting 20 of: '· i) omhyllingsfølerinnretning for sensing at least lysspredningskarakteristikk to flow at OMPI envelope sensing point along this subsequent said disturbance and for producing a surface character output signal 25 proporsonalt. With this, ii) overflatekarakteranalyse-innretni.ng to provide an output signal at least selectively react on the surface character output signal, and iii) amplitudejusteringsinnretning responsive to 30 overflatekrakteranalyseinnretningen to adjust the amplitude of the disturbance means for establishing and maintaining breakpoint at omhyllingsfølerpunktet.

2. System according to claim l, characterized in that the amplitudejusteringsinnretningen comprises an about 35 sets, reacting driver and controlled amplitudeoscillatorinn- • direction for actuating the translates driver transducer for selectively altering the amplitude of the disturbance applied current.

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18:03 · system of claim 1, ka'rakteri in that the .overflatekarakteranalyseinnretningen comprises a waveform characteristics hetelctorgenerator, reference waveform lcarakteri stikkinnstillings means for generating 5 an output signal corresponding to desired waveform characteristics of overflatekarakterutgangs signal when omhyllingsfølerpunktet disposed at break point, and an error signal generator for comparing the output signals of the reference waveform characteristics setting means 10 and waveform characteristics detector generator, said error signal generator comprising means for generating a proporsonalt error signal in response to compared differences therebetween.

if. The system of claim 1, which process comprises 15 by omhyllingsfølerinnretningen comprises ^ a radiation energy source in relation to the 'omhyllingsstrømdelen is at vesenflige translucent, and a radiant energy receiver for measuring at least spread to radiant energy using omhyllingsstrømdelen and to give-20 an output signal proporsonalt thereto.

3. A method for electrostatic sorting particles, characterized in: a) establishing the flow of a continuous particle containing stream comprising at 'least 25 a particle containing core stream and a surrounding about-hylningsstrøm, said stream has a particle sensor point defined therealong, b) optical detection of particles at least at the particle sensor point 30 c) disturbance of the stream with at least a preselected frequency and amplitude to cause said stream to form a breakpoint at which the stream becomes a series discrete droplets, d) the relative charge selected drops when 35 is formed at the breakpoint, and "e) synchronizing the relative charging such that the selected droplets contain at least selected particles • detected by the optical step of detecting, said synchro- in I- 19 * seringstrinnet comprises the steps of:" i) sensing at least light diffusing characteristics of the stream at a omhyllingsfølerpunkt therealong downstream from the interruption to provide a surface 5 character output signal proporsonalt thereto, ii) analyzing the surface character output signal to produce an output signal that is at least selectively reactive to surface character output signal, and · '10 iii) 'adjustment of the selected amplitude disturbances sestrinnet response to the selective reacting starting sigrialet to establish and maintain the break point at about-hyllingsfølerpunktet.

6. A method according to claim 7> character i-15 in that the step of analyzing over.f latekarak-.

terutgangssignalet comprises providing a strømoverflate- 'character output waveform, generating a referansebølge- shape setting that corresponds to a desired waveform characteristic of the surface character output signal when on-20 hyllingsfølerpunktet is located at the breakpoint, and comparing the waveforms to generate an error signal proporsonalt with the comparative difference therebetween, 7. A method according to claim 7 »characterizing in that the step of sensing lysspredningskarakter- 25 istikken to flow comprises selecting a radiation energy source with respect to which at least omhyllingsstrøm portion is essentially translucent, focusing the radiant energy source on at least omhyllingsstrømmen by omhyllingsfølerpunktet, and measurement of at least the dispersion 30 of the radiant energy produced by omhyllingsstrøm-iii by one omhyllingsfølerpunktet to provide said surface character output signal.

8. .Fremgangsmåte claim 7> wherein the step of selection of radiation energy 35 consists in selecting a light source with regard to ".

• which omhyllingsstrømmen is substantially translucent.