EP3378574B1 - Method and device for separating and handling of particles from a particle supply - Google Patents

Description

The invention relates to a method and a device for separating and handling particles from a particle supply, consisting of a sample table with the particle supply and a traversable in xyz direction pipette, wherein the particles have a mass down to the μg range and particle sizes of below 150 microns have.

The separation and handling of such particles is required, for example, in the hydration of pulverized substances, wherein quantities of different particles in the pg range are to be mixed.

From the DE 101 57 032 A1 For example, a method and a device for sorting particles from a particle mixture has become known, in which the particle mixture with particles to be sorted out is moved relative to a collecting device. For sorting specific particles, they are irradiated with pulsed electromagnetic radiation, whereby particles which reflect and / or absorb electromagnetic radiation in a defined wavelength range receive an acceleration, so that they are moved into the collecting device.

Furthermore, in the US 5 101 978 a device for Sorting out two or more materials from a suspension. Here too, a stream of successive particles, such as red and white blood cells, is generated in a flow channel, and in each case identical particles are diverted into one of two output ports by means of a control device.

These devices are complex to implement and not suitable for the separation of particularly small and pulverized particles.

The invention has for its object to remove the aforementioned particles from a particle supply, transport and store targeted and with high accuracy on a storage location.

The problem is solved by the characterizing features of the independent claims.

Particular embodiments of the invention will become apparent from the accompanying dependent claims.

The device according to the invention consists of a sample table with a particle supply of particles, which is connected to a vibration generator for supplying mechanical vibration energy to form a gas-solid particle mixture over the sample table, wherein above the gas-solid-particle mixture in a xyz-direction movable pipette is arranged with a pinhole for receiving particles from the gas-solid-particle mixture, which is connected to a device for generating a negative pressure and wherein between the pipette and the pinhole a pulse generator for generating of electro-acoustic pulses is located.

The sample table is preferably connected to motors for generating vibration energy. Alternatively, it is also possible to use piezoelectric actuators for generating vibrational energy instead.

In order to create a defined location for the production of the gas-solid particle mixture, the sample table is bounded laterally by an edge.

In a further embodiment, the pinhole diaphragm consists of microtechnically structured silicon or glass and is provided with a pore or a pore array.

In order to ensure easy detachment of detected particles from the pinhole, this is coated with an anti-adhesive layer, which preferably consists of a carbon-fluorine compound.

In continuation of the invention, the pipette for receiving particles from the gas-solid-particle mixture and for transporting and depositing particles or a particle array in a target position, is attached to a receptacle of an x-y-z positioning device.

Furthermore, located above the sample table with the particle supply and the gas-solid-particle mixture generated thereupon, a light barrier for leveling thereof and an active optical image recognition device.

• Ausbilden einer Schicht eines Gas-Feststoff-Partikelgemisches über einem Partikelvorrat mit den zu vereinzelnden Partikeln durch Anregen desselben mittels Schwingungen, so dass sich im Gas-Feststoff-Partikelgemisch Partikel in chaotischer Bewegung und hoher kinetischer Energie ohne Bindung zu benachbarten Partikeln aufhalten,
• schrittweises Absenken einer mit einer Lochblende am Ausgang versehenen Pipette in Richtung zur Oberfläche des Gas-Feststoff-Partikelgemisches und Erzeugen eines Unterdruckes oder einer Folge von Unterdruckimpulsen am Ausgang der Pipette, bis mindestens ein Partikel an der Lochblende haftet,
• Transportieren des infolge des Unterdrucks an der Pipette haftenden mindestens einen Partikels über einen vorgesehenen Ablageort, und
• Ablösen des mindestens einen Partikels von der Lochblende der Pipette durch Erzeugen eines mechanischen Energieimpulses sowie schwerkraftbedingte Ablage des Partikels am Ablageort.

The inventive method for separating and handling of particles from a gas-solid-particle mixture is characterized by the following steps:

• Forming a layer of a gas-solid particle mixture over a particle supply with the particles to be separated by exciting it by means of vibrations, so that in the gas-solid particle mixture particles in chaotic motion and high kinetic energy without binding to adjacent particles,
• stepwise lowering a pipette provided with a pinhole at the exit in the direction of the surface of the gas-solid particle mixture and generating a negative pressure or a sequence of negative pressure pulses at the outlet of the pipette until at least one particle adheres to the pinhole,
• Transporting the at least one particle adhering to the pipette as a result of the negative pressure via a designated storage location, and
• Detachment of the at least one particle from the pinhole of the pipette by generating a mechanical energy pulse and gravity-induced deposition of the particle at the storage location.

In a further development of the method according to the invention, the pipette is moved vertically in the direction of the gas-solid-particle mixture and is moved stepwise under active optical image recognition into the gas-solid-particle mixture, up to the pipette At least one particle is detected, whereupon the movement is stopped.

Fig. 1:

eine schematische Übersichtsdarstellung der erfindungsgemäßen Vorrichtung zur Vereinzelung und Handhabung von Partikeln aus einem Partikelvorrat; und

Fig. 2:

eine vergrößerte Unteransicht einer Lochblende zur Entnahme von Partikeln aus einem Gas-Feststoff-Partikelgemisch.

The invention will be explained in more detail using an exemplary embodiment. In the accompanying drawings show:

Fig. 1:

a schematic overview of the device according to the invention for the separation and handling of particles from a particle supply; and

Fig. 2:

an enlarged bottom view of a pinhole for removing particles from a gas-solid-particle mixture.

The device for receiving particles 1 from a particle supply 2 according to Fig. 1 consists of a pinhole 3 with at least one hole at the exit of a pipette 4, which is attached to a receptacle 5 of an xyz positioning device, not shown. Thus, the pinhole 3 can be moved freely with the pipette 4 relative to the particle supply 2. The particle supply 2 is located on a sample table 6, which is bounded laterally by an edge 7. The sample table 6 is coupled to a vibration generator 8 in order to enable the sample table 6 to vibrate in order to produce a gas-solid-particle mixture 10, consisting of a plurality of particles 1, above the particle supply 2. In addition, the sample stage 6 can have a heater in order to be able to provide a sufficiently dry particle supply 2 and to minimize the adhesion / cohesion of the particles 1 in the gas-solid-particle mixture 10.

The perforated plate 3 is connected to a vacuum connection 9 in order to be able to generate a suitable holding force by means of negative pressure, vacuum or vacuum pulses, so that particles 1 can be sucked from the gas-solid particle mixture 10 over the particle supply 2 at the pinhole 3.

To generate the gas-solid particle mixture 10, energy is supplied to the sample table 6 via the vibration generator 8, such as vibration energy, so that the particles 1 begin to move in the particle supply and leave it with sufficient energy supply. As a result, a chaotic gas-solid-particle mixture 10 forms above the particle reservoir 2, in which the particles move chaotically with high kinetic energy without binding to adjacent particles.

The prerequisite for this is that the vibrations generated, such as ultrasonic vibrations, are mainly directed against gravity. The energy supplied to the particle supply 2 on the sample table 6 can also be generated by motors or by piezoelectric actuators.

In the gas-solid-particle mixture 10, particles 1 hold in chaotic motion and high kinetic energy, so that the particles 1 can not build up bonds to adjacent particles 1. Only then is it possible to be able to absorb particles 1 with the pinhole 3 with the smallest possible expenditure of energy. The phrase "lowest possible energy expenditure" means that the holding force is equal to, or nearly equal to, the weight of the particle 1.

The inclusion of particles 1 takes place by focusing an energy pulse at the pinhole 3, in the form of a vacuum pulse, or a series of negative pressure pulses until at least one particle 1 adheres to the pinhole 3. Particles 1 with a diameter that are smaller than the diameter of the opening in the pinhole 3, are sucked through the pinhole 3 and separated out into a particle separator, not shown.

In order to achieve a faster absorption of particles 1, located at a predetermined distance above the sample table 6 with the particle supply 2, a light barrier 12, which is used together with the vibration generator 8 for leveling the gas-solid particle mixture 10 generated above the sample table 6 , This can basically be done by a simple control loop, on the one hand, the vibration energy of the vibrator 8 increases until the photocell 12 detects the presence of particles 1 on the particle supply 2, whereupon the further increase of the vibration energy is stopped by the control loop. In the event that the light barrier 12 registers a particle increase over a predetermined value, i. a greater attenuation of the emitted light, then the control circuit will reduce the vibrational energy of the vibrator 8 until the desired target value of the attenuation is reached again.

The inclusion of particles 1 with the pipette 4 can now be carried out as described above by the pipette 4 is lowered so far in the direction of the gas-solid-particle mixture 10 until the inclusion of a particle 1, for example, with Help an active optical image recognition device (not shown) is detected.

The at least one particle 1 can then be transported with the aid of the x-y-z - positioning to a designated storage location and stored there controlled.

The deposition of particles 1 is again energy-minimized by impressing an energy pulse, such as an electro-acoustic pulse. For this purpose, located at the pinhole 3 and the shaft of the pipette 4, a pulse generator 11, which may be a piezoelectric actuator or a piezoceramic crystal.

In principle, the detachment of the particles 1 from the pinhole 3 can also be effected by an (air) pressure pulse, but this is critical insofar as the particle 1 could be accelerated too much at too high a pressure pulse. In addition, disturbing air turbulence at the storage location would result. A targeted storage of particles would not be possible then.

The pinhole 3 may consist of microtechnically structured silicon or glass and may be a pore or a pore array, as in Fig. 2 shown, so that the inclusion of a defined number of particles from the gas-solid-particle mixture 10 is ensured. The diameter of the pore or the pores of the pore array depends on the size of the particles to be separated 1, whose diameter must be slightly larger than the diameter of the pore.

To a lowest possible holding force for the particles 1 to reach, the pinhole 3 can be coated with an anti-adhesive layer, such as a carbon-fluorine compound.

The method according to the invention comprises the provision of a particle reservoir 2 located on a sample table 6 with the particles 1 to be separated in a gas atmosphere, such as air, inert gas or another carrier gas. Subsequently, a layer of a gas-solid particle mixture 10 over the particle supply 2 with the particles 1 to be separated by exciting the particle stock 2 by means of energy supply, such as mechanical vibrations, e.g. Ultrasonic vibrations generated by a vibrator 8, so that in the forming over the particle supply 2 gas-particulate mixture particles 10 particles 1 in chaotic motion and with high kinetic energy without binding to adjacent particles.

It is advantageous in this case to use the above-described leveling of the gas-solid particle mixture 10 with the aid of a light barrier in order to ensure an approximately constant level of the upper limit of the fluidized-up particles 1.

Subsequently, the pipette 4 provided with a pinhole 3 at the exit is moved in the direction of the surface of the gas-solid particle mixture 10 and generates a series of negative pressure pulses, or negative pressure at the outlet of the pipette 4 until at least one particle 1 adheres to the pinhole 3. The detection of adhering to the pipette 4 particles 1 can be done by optical detection.

The now adhering due to the negative pressure at the pinhole 3 at least one particle 1 is now transported via a designated storage location and replaced by generating a short-term energy pulse by means of the power generator 6 of the pinhole 3 of the pipette 4 and stored by the following gravitational support at the intended location.

LIST OF REFERENCE NUMBERS

1

particle

2

particles stock

3

pinhole

4

pipette

5

Shooting for x-y-z positioning device

6

sample table

7

edge

8th

vibrator

9

vacuum connection

10

Gas-solid particle mixture

11

pulse generator

12

photocell

Claims (12)

1. Device for separating and handling particles from a particle supply, consisting of a sample table with the particle supply and a pipette that can be moved in the x-y-z direction, the particles having a mass down into the µg range and grain sizes of below 150 µm, characterized in that the sample table (6) is connected to a vibration generator (8) for supplying mechanical vibrational energy for the forming of a gas-solid particle mixture (10) over the sample table, in that a pipette (4) with a perforated orifice plate (3) for receiving particles (1) from the gas-solid particle mixture (10) is arranged over the gas-solid particle mixture (10) and is connected to a device for generating a negative pressure, and in that between the pipette (4) and the perforated orifice plate (3) there is a pulse generator (11) for generating electro-acoustic pulses.
2. Device according to Claim 1, characterized in that the sample table (6) is connected to motors for generating vibrational energy.
3. Device according to Claim 1, characterized in that the sample table (6) is connected to piezoelectric actuators for generating vibrational energy.
4. Device according to Claim 1, characterized in that the sample table (6) is laterally surrounded by a border (7) .
5. Device according to Claim 1, characterized in that the perforated orifice plate (3) consists of microtechnically structured silicon or glass.
6. Device according to Claim 5, characterized in that the perforated orifice plate (3) comprises a pore or an array of pores.
7. Device according to Claims 5 and 6, characterized in that the perforated orifice plate (3) is coated with a nonstick layer.
8. Device according to Claim 7, characterized in that the nonstick layer consists of a carbon-fluorine compound.
9. Device according to one of Claims 1 to 8, characterized in that the pipette (4) is fastened on a receptor (5) of an x-y-z robot for receiving particles (1) from the gas-solid particle mixture (10) and for transporting and depositing particles (1) or an array of particles in a target position.
10. Device according to one of Claims 1 to 9, characterized in that arranged over the sample table (6) with the particle supply (2) are a light barrier (12), for levelling the same, and also an active optical image recognition device.
11. Method for separating and handling particles from a gas-solid particle mixture, characterized by

    - forming a layer of a gas-solid particle mixture (10) over a particle supply (2) with the particles (1) to be separated by exciting the same by means of vibrations, so that particles (1) are kept in chaotic motion and at a high level of kinetic energy, without bonding to neighbouring particles (1), over the gas-solid particle mixture (10),

    - gradually lowering a pipette (4), provided with a perforated orifice plate (3) at the outlet, in the direction of the surface of the fluidized gas-solid particle mixture (10) and generating a negative pressure or a sequence of negative pressure pulses at the outlet of the pipette (4), until at least one particle (1) attaches itself to the perforated orifice plate (3),

    - transporting the at least one particle (1) attached to the pipette (4) as a result of the negative pressure over an intended depositing location, and

    - releasing the at least one particle (1) from the perforated orifice plate (3) of the pipette (4) by generating an energy pulse and depositing the particle (10) by gravitational force at the depositing location.
12. Method according to Claim 11, characterized in that the pipette (4) is moved vertically in the direction of the fluidized gas-solid particle mixture (10) and is gradually moved into the fluidized gas-particle mixture (10), with the optical image recognition active, until the at least one particle (1) is detected at the pipette (4), whereupon the movement is stopped.

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