Method for dosing liquid by means of a pipette and a syringe, and pipette for actuating a syringe for dosing liquid

Abstract

A pipette with an adjustable dosing increment, wherein a control apparatus determines a dosing volume by a set dosing increment when a syringe is inserted in the pipette, and determines a maximum possible number of dosing steps following an execution of a reverse stroke without refilling the syringe given the set dosing increment and completely or partially filled syringe by the position of a displacement means on the path, and displays the maximum number of dosing steps on a display apparatus until the reverse stroke is executed. The control apparatus also determines the number of executed dosing steps and displays the number of executed dosing steps and/or the number of dosing steps still possible without refilling the syringe on the display apparatus.

Claims

1. A pipette (1) for handling a syringe (3), comprising: a rod-shaped housing (2), a seat (20) having an opening (21.1) at a bottom end of the housing (2) for inserting a syringe (3) having a fastening section (16) at the a top edge of a cylinder (11), a seat body (25) having a second seat (24) and another a second opening (21.2) at the bottom end in the housing (2) for receiving a second fastening section (19) of a plunger (12) of the syringe (3), means for releasably holding the fastening section (16) in the seat (20) and the second fastening section (19) in the second seat (24), and at least one means for displacing the seat body (25) within the housing (2) in a longitudinal direction of the housing (2), the housing further having a drawing lever (5) that can be actuated outside of the housing (2) for drawing liquid into the syringe (3), a control button (8) that can be actuated outside of the housing (2) for the a stepwise discharging of liquid from the syringe (3), an adjusting element for adjusting a dosing increment amount that can be adjusted outside of the housing (2), means for detecting the dosing increment amount set with the adjusting element, means for detecting the syringe (3) releasably connected to the pipette (1), means for detecting a respective position of the at least one means for displacing the seat body (25) during displacement of the at least one means for displacing along a path relative to the housing (2), an electronic control apparatus (42) connected to each of the means for detecting, and an electronic display apparatus (9) connected to the electronic control apparatus (42), wherein the control apparatus (42) is configured to determine a dosing volume determined by the set dosing increment amount when the syringe (3) is inserted in the pipette (1), and determine a maximum possible number of dosing steps following an execution of a reverse stroke without refilling the syringe (3) given the set dosing increment amount and the position of the at least one means for displacing on the path, and display the determined maximum possible number of dosing steps and the position of the at least one means for displacing on display apparatus (9), the control apparatus configured to determine an execution of a reverse stroke to be executed by the actuation of the control button (8), and indicates the determination of the execution of a reverse stroke to be executed on the display apparatus (9) until the reverse stroke is executed, and the control apparatus determines the number of executed dosing steps and displays the number of executed dosing steps determined on the display apparatus (9).

2. The pipette (1) according to claim 1, wherein the means for detecting the respective position of the at least one means for displacing the seat body (25) has an incremental encoder arranged on the at least one means for displacing and at least one sensor (44) fixedly arranged in the housing (2) and connected to the control apparatus (42) for detecting the displacement of the incremental encoder.

3. The pipette (1) according to claim 2, wherein the at least one means for displacing is a toothed rack (27) having a bottom end which is connected to the seat body (25) that can be engaged with a pawl (37) pivotably mounted on the control button (8) so that when the control button (8) is actuated to displace the toothed rack (27) a dosing step is completed.

4. The pipette (1) according to claim 2, wherein the incremental encoder is integral with the toothed rack (27), or is a component securely connected to the toothed rack (27).

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The invention is explained in greater detail below based on the appended drawings of an exemplary embodiment. In the drawings:

(2) FIG. 1 shows a pipette according to the invention with a syringe held therein in a perspective view from the side,

(3) FIG. 2 shows the same pipette with the syringe held therein in a front view;

(4) FIG. 3 shows the same pipette with the syringe held therein in a side view;

(5) FIG. 4 shows the same pipette with the syringe held therein in a longitudinal section;

(6) FIG. 5 shows a seat body with a toothed rack with a magnetic strip, connecting element, drawing lever and cover wall of the same pipette in an enlarged section in a longitudinal direction;

(7) FIG. 6 shows an alternate arrangement to FIG. 5 with a rotary encoder coupled by a gear drive in a side view;

(8) FIG. 7 shows an alternate arrangement to FIG. 5 with a contact sensor aligned with a molded-on scale in a side view;

(9) FIG. 8 shows an alternate arrangement to FIG. 5 with an optical sensor aligned with a molded-on scale in a side view;

(10) FIG. 9 shows a method for dosing when the syringe is partially filled in a block diagram;

(11) FIG. 10 shows a method for dosing in a faulty dosing step in a block diagram;

DETAILED DESCRIPTION OF THE INVENTION

(12) In the present application, the designations “top” and “bottom” refer to the alignment of the pipette in which the rod-shaped housing is aligned vertically, and the seat for the syringe is arranged at the bottom.

(13) According to FIGS. 1 to 3, a pipette 1 has a rod-shaped housing 2 in which a syringe 3 is held at the bottom. A drawing lever 5 projects from the housing 2 from a sidewall of the housing 2 over a straight slot 4. A control button 8 of a toothed rack/pawl control projects from the same side wall of the housing above two additional slots 6, 7. Above that, a display apparatus in the form of an LCD display 9 is recessed in the same side wall of the housing 2. Segments of a selection wheel 10 project from openings in the adjacent sidewalls.

(14) According to FIG. 4, the syringe 3 has a cylinder 11 and a plunger 12 movably arranged therein. The cylinder 11 has a conical section 13 at the bottom with a hole 14 for the passage of liquid, and a cylindrical section 15 above that in which the plunger 12 can be displaced. At the top, the cylinder 11 has a fastening section 16 with a peripheral flange 17. From the plunger 12, a plunger rod 18 projects upward and has another fastening section 19 with a plurality of peripheral beads.

(15) The syringe 3 is arranged with the flange 17 in a seat 20 on the bottom end of the housing 2 that has an axially directed opening 21.1 in the bottom end of the housing 2 for inserting and removing the syringe 3. The syringe 3 presses with its top side against a pressure sensitive ring sensor 22 that senses the projections on the top edge of the flange 17. The flange is 17 is held in this position by gripping levers 23 in the housing 2.

(16) The additional fastening section 19 of the plunger 12 is arranged in an additional seat 24 in a hollow cylindrical seat body 25. This has another axially directed opening 21.2 for inserting the additional fastening section 19. The additional fastening section 19 is held by additional gripping levers 26 that engage between the beads of the additional fastening section 19 or clamp them.

(17) The seat body 25 is securely connected to a toothed rack 27 that extends below the slot 4 in the longitudinal direction of the housing 2.

(18) A drawing lever holder 28 is fixed to the seat body 25 and the bottom part of the toothed rack 27.

(19) Furthermore, there is a drawing lever support 29 30 that lies with a slide plate against the bottom side of the edges of the slot 4. The slide plate 30 has a spike 31 that projects upward and penetrates the slot 4. The drawing lever 5 is fixed to the spike 31 outside of the housing 2.

(20) In the upper half of the housing 2, a dosing lever 34 is pivotably mounted in a pivot bearing 32 in a bulge 33 in the side wall of the housing 2 opposite the slot 4. The dosing lever 34 has two legs 35, 36 at a distance from each other that extend on the opposite side wall of the housing 2 out of the two slots 6, 7. The control button 8 is fixed on the ends of the legs 35, 36 extending out of the housing 2.

(21) A pawl 37 is pivotably mounted between the two legs 35, 36 of the dosing lever 34. The pawl 37 is arranged with a pawl tooth 38 above the teeth 39 of the toothed rack 27. The dosing lever 34 is pressed by a spring apparatus (not shown) into the position in FIG. 4. The dosing lever 34 can be swung downward by actuating the control button 8 counter to the effect of the spring apparatus. The pawl 37 is pressed into the teeth 39 of the toothed rack 27 by means of another spring apparatus (not shown).

(22) A movable cover 40 is arranged between the pawl 37 and toothed rack 27. The cover 40 is displaceable by turning the selection wheel 10 projecting out of the side of housing 2 so that the teeth 39 of the toothed rack 27 are more or less covered.

(23) Furthermore, a printed circuit board 41 with electronics is arranged in the upper half of the housing 2. The electronics comprise an electronic control apparatus 42. An electrical voltage supply in the form of batteries or a rechargeable batteries 43 is also located there.

(24) The selection wheel 10 is assigned another sensor 44 that detects the rotary position of the selection wheel 10. The measured values determined by the ring sensor 22 and the additional sensor 44 are forwarded to the control apparatus 42 via the cable.

(25) The code indicated on the flange 17 denotes the size of the respective syringe 3. The control apparatus 42 determines the respective syringe size from the measurement signals supplied by the ring sensor 22, and the respective increment from the setting of the selection wheel 10. From this, it calculates the set dispensing volume and presents it on the display 9.

(26) The slots 6, 7 are covered on the inside by a shield 45 connected to the dosing lever 34.

(27) According to FIG. 4 und 5, there is a flexible cover strip 46 under the slot 4 in the housing 2 for covering the slot 4. The cover strip 46 consists of polypropylene. On the ends, it is secured in the housing on both sides of the slot 4.

(28) According to FIG. 4 und 5, the cover strip 46 runs through a channel 47 between the drawing lever holder 28 and drawing lever support 29.

(29) Further details about the cover strip 46 and the related embodiments of the housing 2, the drawing lever holder 28 and the drawing lever support 29 are described in EP 2 656 916 A1 in paragraphs 65 to 69, the content of which is hereby incorporated in the present application.

(30) According to FIGS. 4 and 5, the magnetic strip 48 is arranged on the back of the toothed rack 27 and extends in the longitudinal direction of the toothed rack 27. In the longitudinal direction, the magnetic strip 48 comprises a plurality of sequential magnetic elements that are arranged at a predetermined distance (segmentation) next to each other. A magnetic sensor 49 is arranged on the side of the printed circuit board 41 facing the toothed rack 27, and it is suitable for detecting the displacement of the magnetic strip 48. The magnetic sensor 49 is wired to the control apparatus 42.

(31) Moreover, the pipette has a transmission element 50 in the housing for controlling a reverse stroke when the syringe 3 is completely filled. Details on the transmission element 50 and its function are described in EP 2 656 916 A1 in paragraphs 71 to 74 and 81 to 83, as well as the figures referenced therein, the content of which is hereby incorporated in the present invention.

(32) FIG. 6 shows another embodiment in which the translatory movement of the toothed rack 27 is transmitted via additional teeth 51 of the toothed rack 27 to a pinion 52 that is connected to a rotary encoder 53. The rotary encoder 53 is connected by a cable to the control apparatus 42 for reporting the respective position of the toothed rack 27.

(33) In the embodiment in FIG. 7, a contact sensor 54 senses additional teeth 51 of the toothed rack 27. The contact sensor 54 is connected by a cable to the control apparatus 42 for reporting the respective position of the toothed rack 27.

(34) In the embodiment in FIG. 8, an optical sensor 55 senses teeth 39, 51 of the toothed rack 27. These can be the teeth 39 that interact with the pawl 37, or additional teeth 51. The optical sensor 55 is connected by a cable to the control apparatus 42 for notifying it of the respective position of the toothed rack 27.

(35) The use of the pipette 1 from FIGS. 1 to 5 will be explained with reference to FIG. 9. First a syringe 3 with a syringe size selected by the user is releasably connected to the pipette 1 by inserting it with the fastening section 16 in the seat 20, and with the additional fastening section 19 in the seat 24, so that the flange 22 is gripped by the gripping levers 23, and the fastening section 19 is gripped by the additional gripping levers 26.

(36) The ring sensor 22 senses the code on the flange 17 of the syringe 3. With the signals provided by the ring sensor 22, the control apparatus 42 discerns that a syringe 3 has been inserted and turns on the display 9. With the signals provided by the ring sensor 22 and by the sensor 44, the control apparatus 42 determines the set dispensing volume and presents it on a display 9.

(37) Moreover, the control apparatus 42 determines the possible number of dosing steps for draining the syringe 3 after complete filling, and shows them on the display 9 (block 60).

(38) The user may change the setting of the dispensing volume using the selection wheel 10, and the changed metering volume is shown on the display 9 (block 61).

(39) To draw liquid through the opening 14 in the syringe 3, the drawing lever 5 is pressed upward out of the position in FIGS. 1 to 3, wherein the magnetic sensor 49 detects the displacement of the toothed rack upward and forwards it to the control apparatus 42. Consequently, the control apparatus 42 controls a flashing of the display (block 62).

(40) Likewise, the magnetic sensor 49 detects termination of the drawing of liquid by a stoppage or downward movement of the toothed rack 27, and forwards this to the control apparatus 42. Then the control apparatus 42 indicates on the display 9 the maximum possible number of dosing steps for refilling the syringe at the respective fill level (block 62).

(41) After the reverse stroke to be executed has been performed by actuating the control button 8 once or several times, the control apparatus 42 controls the display 9 so that it stops flashing (block 63).

(42) The performance of the reverse stroke is detected by the control electronics 42 due to the displacement of the toothed rack 27 detected by the magnetic sensor 49.

(43) FIG. 9 shows the steps of partial filling. Alternatively when the syringe 3 is completely filled, the maximum possible number of dosing steps without filling this syringe 3 is displayed. When the syringe is completely filled, due to the transmission element, the reverse stroke can be performed by actuating the actuation button 8 once.

(44) Individual dosing steps are performed by repeatedly actuating the actuation button 8. The performance of dosing steps is also determined by the magnetic sensor 49 from which the control apparatus 42 calculates the number of performed dosing steps and/or the number of remaining dosing steps, and causes them to be displayed on the display 9 (block 64).

(45) After the last complete dosing step is dispensed, the control electronics stop counting. Then fluid can again be drawn with the same syringe 3 so that the procedure continues with block 60. The control electronics 42 cause all of the performed dosing steps to be displayed (block 65).

(46) Alternatively, the remaining fluid is dispensed by actuating the drawing lever 5. Then the control apparatus 42 controls a flashing of the display 9 (block 66) in addition to the display of the set dosing volume and the reached dosing steps.

(47) When the syringe 3 is ejected by opening the gripping levers 23, 26, it is no longer detected by the ring sensor 22, and the control apparatus 42 switches off the display 9 (block 67).

(48) A step error will be explained with reference to FIG. 10.

(49) Blocks 60 to 64 correspond to FIG. 9.

(50) When there is an incorrect dosing, it is determined by the control electronics 42 due to the displacement reported by the magnetic sensor 49 which does not correspond to the set dosing step. Then a buzzer emits a warning tone (block 68).

(51) If the actuation button 8 remains actuated, the control apparatus 42 controls the display 9 so that only the number of steps performed up to the incorrect dosing is displayed, and the display flashes. In this embodiment version, it is not possible to continue counting by repeatedly actuating the actuation button (block 69).

(52) In the next step, residual liquid can be dispensed by actuating the drawing lever 5, wherein the number of dosing steps up to the incorrect dosing is still displayed, and the display 9 flashes (block 70).

(53) Finally, the control apparatus 42 controls when ejecting the syringe so that the display goes blank (block 67).

(54) The entire contents of all of the references discussed above are each hereby incorporated by reference in their entirety

REFERENCE NUMBER LIST

(55) 1 Pipette 2 Housing 3 Syringe 4 Slot 5 Lifting lever 6, 7 Additional slot 8 Control button 9 Display apparatus 10 Selection wheel 11 Cylinder 12 Plunger 13 Conical section 14 Hole 15 Cylindrical section 16 Fastening section 17 Flange 18 Piston rod 19 Additional fastening section 20 Seat 21.1 Opening 21.2 Additional opening 22 Ring sensor 23 Gripping lever 24 Additional seat 25 Seat body 26 Gripping lever 27 Toothed rack 28 Drawing lever holder 29 Drawing lever support 30 Slide plate 31 Spike 32 Pivot bearing 33 Bulge 34 Dosing lever 35, 36 Legs 37 Pawl 38 Pawl tooth 39 Teeth 40 Cover 41 Printed circuit board 42 Control apparatus 43 Battery 44 Sensor 45 Shield 46 Cover strip 47 Channel 48 Magnetic strip 49 Magnetic sensor 50 Transmission element 51 Teeth 52 Pinion 53 Rotary encoder 54 Contact sensor 55 Sensor