Measuring device

Abstract

To provide a weighing device that can easily and accurately weigh powdered materials. [Solution] The weighing device 1 comprises a nozzle 2 on which a pipette tip 12, which is cylindrical and has a filter inside the middle of its axial direction, is detachably attached; a support part on which the nozzle 2 is supported; a suction device 4 connected to the pipette tip 12 via the nozzle 2 and sucking air from inside the pipette tip 12; a discharge device 5 connected to the pipette tip 12 via the nozzle 2 and discharging air from inside the pipette tip 12 to the outside; a first mass measuring instrument 6 for measuring the mass of powdered material; and a second mass measuring instrument 7 for measuring the mass of powdered material transported from the first mass measuring instrument 6 using the suction device 4 and the discharge device 5. The first mass measuring instrument 6 measures the mass after the powdered material has been sucked up by the suction device 4, before the powdered material is transported to the second mass measuring instrument 7.

Description

Technical Field

[0006] , , ,

[0005] , ,

[0001] The present invention relates to a weighing device capable of measuring the mass of a powder.

Background Art

[0002] Patent Document 1 below discloses a pipette device for powder used when dispensing a predetermined amount of powder. In this pipette device for powder, a chip having a filter inside is used. In the chip, the volume of the suction space on the tip side of the filter is preset. Therefore, by filling the inside of the suction space described above with the aspirated powder, the powder to be dispensed can be made a predetermined amount. When powder is aspirated into the suction space described above, the excess powder protruding from the opening of the chip is dropped from the chip by vibrating the chip.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] (2) In the above (1), it is preferable to further include a vibrator provided on the nozzle for vibrating the pipette tip, and a pressure restoration means for restoring the pressure inside the pipette tip, which has been reduced by the suction device, to atmospheric pressure.

[0008] (3) In (2) above, it is preferable that the depressurization operation by the suction device and the repressurization operation by the repressurization means are repeated while the pipette tip is vibrated by the vibrator.

[0009] (4) In any of (1) to (3) above, it is preferable to further include a vibrator that vibrates the pipette tip provided on the nozzle, and a suction force adjusting means that reduces the suction force acting inside the pipette tip by the suction device.

[0010] (5) In (4) above, it is preferable to perform the suction force reduction operation by the suction force adjustment means intermittently while the pipette tip is being vibrated by the vibrator and the decompression operation by the suction device is being performed.

[0011] (6) In the above (1), it is preferable to further include a vibrator provided on the nozzle for vibrating the pipette tip, a pressure restoration means for restoring the pressure inside the pipette tip, which has been reduced by the suction device, to atmospheric pressure, and a suction force adjustment means for reducing the suction force acting inside the pipette tip by the suction device. [Effects of the Invention]

[0012] According to the present invention, a weighing device can be provided that can easily and accurately weigh powdered materials. [Brief explanation of the drawing]

[0013] [Figure 1] This is a perspective view showing a weighing device according to one embodiment of the present invention, with some parts omitted. [Figure 2] This is a schematic diagram showing a weighing device according to one embodiment of the present invention. [Figure 3] This is a front view showing the usage state of a weighing device according to one embodiment of the present invention, and it shows the state in which powdered material is being sucked up. [Figure 4] This is a front view showing the usage state of a weighing device according to one embodiment of the present invention, and it shows a state in which a portion of the aspirated powdered material is being discharged. [Figure 5] This is a front view showing the usage state of a weighing device according to one embodiment of the present invention, showing the state in which the aspirated powdered material is being discharged for measurement. [Figure 6] This flowchart shows an example of an operating method for a weighing device according to one embodiment of the present invention. [Figure 7] This flowchart shows another example of an operating method for a weighing device according to one embodiment of the present invention. [Modes for carrying out the invention]

[0014] Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

[0015] Figure 1 is a perspective view showing a weighing device according to one embodiment of the present invention, with some parts omitted. Figure 2 is a schematic configuration diagram showing the weighing device of Figure 1. The weighing device 1 according to this embodiment weighs powdery material. Powdery material includes not only powder but also granular and lumpy material. Examples of powdery material include crushed food, pharmaceuticals, and crushed human feces. The weighing device 1 comprises a nozzle 2, a support part 3, a suction device 4, a discharge device 5, a first mass measuring instrument 6, a second mass measuring instrument 7, a vibrator 8, a pressure restoration means 9, a suction force adjustment means 10, and a controller 11.

[0016] The nozzle 2 is cylindrical and is positioned vertically on the support part 3, which will be described later. Both axial ends of the nozzle 2 are open. A pipette tip 12, which has a filter (not shown), is detachably attached to the nozzle 2. The pipette tip 12 is cylindrical and tapered. A filter is provided inside the pipette tip 12 in the middle of its axial direction. In the illustrated example, the tip of the pipette tip 12 is cut obliquely with respect to the axial direction of the pipette tip 12. The filter is configured to allow air to pass through and to capture powdery material. The filter is located on the proximal end side of the pipette tip 12. A pipette tip 12 with this configuration is provided at the tip of the nozzle 2. Specifically, the pipette tip 12 is attached to the nozzle 2 with the tip of the nozzle 2 inserted into the proximal end opening of the pipette tip 12. When the pipette tip 12 is attached to the nozzle 2, the tip of the nozzle 2 is located on the proximal end side of the pipette tip 12, relative to the filter.

[0017] The support portion 3 that supports the nozzle 2 includes a holding portion 13 that holds the nozzle 2, a vertical member 14 on which the holding portion 13 is movable in the vertical direction, a horizontal member 15 on which the vertical member 14 is movable in the left-right direction, and a support member 16 that supports the horizontal member 15.

[0018] The holding part 13 is in the shape of a substantially rectangular box. The nozzle 2 is held in a state of passing through the holding part 13. In the state where the nozzle 2 is held by the holding part 13, the nozzle 2 is along the vertical direction. In the state where the nozzle 2 is held by the holding part 13, the tip of the nozzle 2 protrudes downward from the holding part 13. A pipette tip 12 is attached to this protruding part.

[0019] The vertical member 14 has a vertical piece 17 arranged along the vertical direction and a drive source 18 for moving the holding part 13 in the vertical direction. At the front end of the vertical piece 17, a plate-like vertical moving piece 19 is provided so as to be slidable in the vertical direction. The vertical moving piece 19 is provided on the vertical piece 17 with its plate surface facing forward and backward. The holding part 13 is detachably attached to the front surface of the vertical moving piece 19 via an attachment piece 20. In the state where the holding part 13 is provided on the vertical moving piece 19, the nozzle 2 is along the vertical direction. The drive source 18 is a means for moving the vertical moving piece 19 in the vertical direction and is typically a motor. The drive source 18 is attached to the vertical piece 17 via a connection piece 21. The connection piece 21 is provided at the upper end of the vertical piece 17. At this time, the right part of the connection piece 21 is attached to the upper end of the vertical piece 17. The drive source 18 is attached to the left part of the connection piece 21. With such a configuration, by driving the drive source 18, the vertical moving piece 19 can be slid in the vertical direction. Therefore, by driving the drive source 18, the nozzle 2 attached to the vertical moving piece 19 can be moved in the vertical direction.

[0020] The horizontal member 15 is arranged along the left - right direction. At the front end of the horizontal member 15, a plate - shaped horizontal moving piece 22 is provided so as to be slidable in the left - right direction. The horizontal moving piece 22 is provided on the horizontal member 15 with its plate surface facing the front - rear direction. On the front surface of the horizontal moving piece 22, a vertical member 14 is detachably provided via a plate - shaped mounting plate 23. At this time, the front surface of the mounting plate 23 is fixed to the rear end portion of the vertical piece 17, and the rear surface of the mounting plate 23 is fixed to the front surface of the horizontal moving piece 22. With such a configuration, by sliding the horizontal moving piece 22 in the left - right direction, the vertical member 14 can be slid in the left - right direction. Therefore, by sliding the horizontal moving piece 22 in the left - right direction, the nozzle 2 attached to the vertical member 14 can be moved in the left - right direction.

[0021] The support member 16 has a pair of leg portions 24, 24 arranged at a distance from each other in the left - right direction, and a horizontal piece portion 25 provided between the pair of leg portions 24, 24. The pair of leg portions 24, 24 has a pair of column pieces 26, 26 arranged at a distance from each other in the front - rear direction, and a connecting piece 27 provided between the pair of column pieces 26, 26. The pair of column pieces 26, 26 extends in the up - down direction and is erected on a plate - shaped base 28. The pair of column pieces 26, 26 are spaced apart in the front - rear direction in the state of being installed on the base 28. The connecting piece 27 is provided so as to bridge the upper end portions of the column pieces 26, 26 spaced apart in the front - rear direction. The pair of leg portions 24, 24 having such a configuration are arranged on the base 28 spaced apart in the left - right direction. The horizontal piece portion 25 is provided so as to bridge the rear end portions of the connecting pieces 27, 27 of the leg portions 24, 24 spaced apart in the left - right direction.

[0022] The horizontal member 15 described above is provided on the horizontal piece portion 25 of the support member 16. The horizontal member 15 is fixed to the front end portion of the horizontal piece portion 25. In the state where the horizontal member 15 is fixed to the horizontal piece portion 25, the horizontal member 15 is along the left - right direction. A drive source 29 for moving the above - described horizontal moving piece 22 is provided on the horizontal piece portion 25 of the support member 16. The drive source 29 is fixed to the front end portion of the horizontal piece portion 25. The drive source 29 is typically a motor. By driving this drive source 29, the horizontal moving piece 22 can be slid left - right with respect to the horizontal member 15. Therefore, by driving the drive source 29, the nozzle 2 can be moved in the left - right direction.

[0023] The suction device 4 is a means for aspirating air from inside the pipette tip 12. As shown in Figure 2, the suction device 4 is connected to the base end opening of the nozzle 2 via the suction passage 30. Therefore, the suction device 4 is connected to the pipette tip 12 attached to the nozzle 2 via the nozzle 2. In this embodiment, the suction device 4 is a vacuum pump. However, the suction device 4 is not limited to a vacuum pump.

[0024] The discharge device 5 is a means for discharging air from inside the pipette tip 12 to the outside. As shown in Figure 2, the discharge device 5 is connected to the base end opening of the nozzle 2 via the discharge passage 31. Therefore, the discharge device 5 is connected to the pipette tip 12 attached to the nozzle 2 via the nozzle 2. In this embodiment, the discharge device 5 is an air compressor capable of discharging compressed air. However, the discharge device 5 is not limited to an air compressor.

[0025] In the illustrated example, the suction passage 30 and the discharge passage 31 are connected to a common passage 32 on the nozzle 2 side. A three-way valve 33 is provided at the connection point between the suction passage 30, the discharge passage 31, and the common passage 32. This three-way valve 33 can be switched between connecting the suction passage 30 and the common passage 32, and connecting the discharge passage 31 and the common passage 32. An air supply passage 34 is connected to the common passage 32, which connects the inside of the common passage 32 to the outside air. A three-way valve 35 is provided at the connection point between the common passage 32 and the air supply passage 34. As a result, the common passage 32 has a first portion 36 located on the nozzle 2 side of the three-way valve 35, and a second portion 37 located on the three-way valve 33 side of the three-way valve 35. The three-way valve 35 can be switched between connecting the aforementioned second portion 37 and the aforementioned first portion 36, and connecting the aforementioned first portion 36 and the air supply passage 34.

[0026] The first mass measuring instrument 6 is a means for measuring the mass of a powder. The first mass measuring instrument 6 is provided with a first container holder 39 that holds a first container 38 containing the powder. The first container holder 39 is a bottomed cylindrical part and is provided on the first mass measuring instrument 6 with an opening at the top. The first container 38 is a bottomed cylindrical part and is held by the first container holder 39 by being inserted into the first container holder 39 through the upper opening of the first container holder 39. With this configuration, the powder can be placed on the first mass measuring instrument 6 once the powder is contained in the first container 38. The first mass measuring instrument 6 can measure the mass of the placed powder. The first mass measuring instrument 6 is typically an electronic balance. In the illustrated example, the first mass measuring instrument 6 is placed on a base 28.

[0027] The second mass measuring device 7 is a means for measuring the mass of powdered material. The second mass measuring device 7 is provided with a second container holder 41 for holding a second container 40 containing the powdered material. The second container holder 41 is a bottomed cylindrical shape and is provided on the second mass measuring device 7 with an opening at the top. The second container 40 is a bottomed cylindrical shape with an upper end that extends outward in a flange shape. The second container 40 is inserted into the second container holder 41 through the upper opening of the second container holder 41. At this time, the upper end of the second container 40 is placed on the upper end surface of the second container holder 41. In this way, the second container 40 is held by the second container holder 41. With this configuration, by placing powdered material in the second container 40, the powdered material can be placed on the second mass measuring device 7. The second container 40 contains powdered material transported from the first container 38 using a suction device 4 and a discharge device 5, as will be described later. Therefore, the second mass measuring instrument 7 can measure the mass of the powdery material transported from the first mass measuring instrument 6 using the suction device 4 and the discharge device 5. The second mass measuring instrument 7 is typically an electronic balance. In the illustrated example, the second mass measuring instrument 7 is placed on the base 28 to the right of the first mass measuring instrument 6.

[0028] The vibrator 8 is a means for vibrating the pipette tip 12 provided on the nozzle 2. The vibrator 8 is provided on the holding part 13 that holds the nozzle 2. In this embodiment, the vibrator 8 is a vibration motor, but it is not limited to this.

[0029] The pressure restoration means 9 restores the pressure inside the pipette tip 12, which has been depressurized by the suction device 4, to atmospheric pressure. The pressure restoration means 9 has the aforementioned air supply passage 34 and the aforementioned three-way valve 35. As shown in Figure 2, when the three-way valve 35 is operated while the inside of the pipette tip 12 is depressurized, outside air is introduced into the pipette tip 12 through the air supply passage 34 and the common passage 32 due to the differential pressure. As a result, the pressure restoration means 9 can restore the pressure inside the pipette tip 12.

[0030] The suction force adjustment means 10 reduces the suction force acting on the pipette tip 12 by the suction device 4. As shown in Figure 2, the suction force adjustment means 10 is located in the suction passage 30 on the side of the suction device 4 than the three-way valve 33. In this embodiment, the suction force adjustment means 10 is a vacuum regulator, but is not limited to this.

[0031] The measuring device 1 of this embodiment includes a discharge force adjustment means 42 that adjusts the discharge force acting on the pipette tip 12 by the discharge device 5. As shown in Figure 2, the discharge force adjustment means 42 is provided in the discharge passage 31 on the discharge device 5 side of the three-way valve 33. The discharge force adjustment means 42 is an electro-pneumatic regulator, but is not limited to this.

[0032] The controller 11 controls the drive sources 18, 29, the suction device 4, the discharge device 5, the vibrator 8, the pressure restoration means 9, the suction force adjustment means 10, and the discharge force adjustment means 42. Therefore, the controller 11 is connected to the drive sources 18, 29, the suction device 4, the discharge device 5, the vibrator 8, the three-way valves 33, 35, the suction force adjustment means 10, and the discharge force adjustment means 42. Also, as will be described later, the controller 11 is connected to the first mass measuring instrument 6 and the second mass measuring instrument 7. The controller 11 weighs the powdered material according to a predetermined procedure, as will be described later. In the illustrated example, the controller 11 is fixed to a pair of legs 24, 24 on the rear side of the lateral piece 25.

[0033] Next, the operation of the weighing device 1 of this embodiment will be described. Figure 3 is a front view showing the weighing device of Figure 1 in use, showing the state in which powdered material is being sucked up. Figure 4 is a front view showing the weighing device of Figure 1 in use, showing the state in which a portion of the sucked powdered material is being discharged. Figure 5 is a front view showing the weighing device of Figure 1 in use, showing the state in which the sucked powdered material is being discharged for measurement. Figure 6 is a flowchart showing an example of how to operate the weighing device of Figure 1. Figures 3 to 5 show the state in use of the weighing device 1 of this embodiment in chronological order.

[0034] The weighing device 1 of this embodiment is used with a pipette tip 12 attached to the nozzle 2. As shown in Figure 3, when weighing powdered material with the weighing device 1, first, the drive source 29 is driven to position the pipette tip 12 above the first container 38 provided in the first mass measuring instrument 6 (S11). When the pipette tip 12 is not positioned above the first container 38, the drive source 29 is driven to move the lateral movement piece 22 in the left-right direction so that the pipette tip 12 is positioned on the first container 38. After the pipette tip 12 is positioned on the first container 38, the suction device 4 is activated (S12). At this time, the three-way valve 33 connects the suction passage 30 and the common passage 32, and the three-way valve 35 connects the first part 36 and the second part 37. After the suction device 4 is activated, the drive source 18 is driven while the suction device 4 is activated. By driving the drive source 18, the pipette tip 12 is inserted into the first container 38 (S13). With the pipette tip 12 positioned above the first container 38, the drive source 18 is driven to move the vertical movement piece 19 vertically so that the pipette tip 12 is inserted into the first container 38.

[0035] After the pipette tip 12 is inserted into the first container 38, the pipette tip 12 stops at a predetermined position within the first container 38. Specifically, the pipette tip 12 is positioned at a preset location by controlling the drive source 18 to stop the vertical movement piece 19. While the pipette tip 12 is stopped, the powdery material in the first container 38 is drawn into the pipette tip 12 by the aspiration device 4 (S14). The duration for which the pipette tip 12 is stopped is preset. For example, the duration for which the pipette tip 12 is stopped is 3 seconds.

[0036] After the pipette tip 12 has stopped for a set period of time, the pipette tip 12 moves upward as shown in Figure 4. With the pipette tip 12 in the stopped position, the drive source 18 is driven to move the vertical movement piece 19 upward so that the pipette tip 12 moves upward. After the pipette tip 12 moves upward, it stops at a predetermined position (S15). Specifically, by controlling the drive source 18 to stop the vertical movement piece 19, the pipette tip 12 is positioned at a preset position. At this time, the pipette tip 12 is at a lower position than when the pipette tip 12 is on the first container 38, and is inserted into the first container 38. In this state, the aspiration device 4 is operating.

[0037] Then, the mass of the powder in the first container 38 is measured by the first mass measuring instrument 6. This is used to determine the mass of the powder drawn into the pipette tip 12 (S16). If the mass of the powder drawn into the pipette tip 12 is greater than the target value (the target mass measured by the second mass measuring instrument 7, which will be described later), the weighing device 1 is operated as follows. When it is determined that the mass of the powder drawn into the pipette tip 12 is greater than the target value, the value obtained by subtracting the mass of the powder remaining in the first mass measuring instrument 6 after the powder has been drawn into the pipette tip 12 from the mass of the powder initially placed on the first mass measuring instrument 6 is compared with the target value. The mass of the powder initially placed on the first mass measuring instrument 6 may be measured by the first mass measuring instrument 6, or a powder of a predetermined mass may be used. The target value is predetermined. The suction device 4 is operating when the measurement is performed by the first mass measuring instrument 6.

[0038] Specifically, when a powdery substance is contained in the pipette tip 12, the pipette tip 12 is vibrated by the vibrator 8, and the depressurization operation by the suction device 4 and the repressurization operation by the repressurization means 9 are repeated (S17). To repeat the depressurization operation by the suction device 4 and the repressurization operation by the repressurization means 9, the three-way valve 35 is operated. The three-way valve 35 alternately switches between a state in which the first part 36 and the second part 37 are connected, and a state in which the first part 36 and the air supply passage 34 are connected. The time during which the repressurization operation by the repressurization means 9 is performed is, for example, 0.5 seconds or less. The number of times the depressurization operation by the suction device 4 and the repressurization operation by the repressurization means 9 are repeated is predetermined and may be once or multiple times. A portion of the powdery substance contained in the pipette tip 12 falls into the first container 38 due to the vibration of the pipette tip 12 and the repeated depressurization and repressurization operations.

[0039] After the vibration of pipette tip 12 stops and after the repeated operation of depressurization and repressurization stops, The mass of the powder in the first container 38 is measured by the first mass measuring instrument 6. This is used to determine the mass of the powder drawn into the pipette tip 12 (S18). If the mass of the powder drawn into the pipette tip 12 is greater than the target value, the process returns to S17. If the mass of the powder drawn into the pipette tip 12 is less than the target value, the suction device 4 is activated (S19). This prevents the powder in the pipette tip 12 from falling any further. When determining whether the mass of the powder drawn into the pipette tip 12 is greater than or less than the target value, the value obtained by subtracting the mass of the powder placed on the first mass measuring instrument 6 after it has fallen into the first container 38 from the mass of the powder initially placed on the first mass measuring instrument 6 is compared with the target value.

[0040] Then, with the powdery material contained in the pipette tip 12, the drive sources 18 and 29 are driven to insert the pipette tip 12 into the second container 40 and stop it. At this time, the aspiration device 4 is operating. With the pipette tip 12 inserted into the second container 40, the powdery material inside the pipette tip 12 is discharged into the second container 40 by the discharge device 5 (S20). At this time, the three-way valve 33 connects the discharge passage 31 and the common passage 32, and the three-way valve 35 connects the first part 36 and the second part 37.

[0041] The mass of the powdery material discharged into the second container 40 is measured by the second mass measuring instrument 7 (S21). If the mass measured by the second mass measuring instrument 7 is, for example, more than 5% of the target value, the mass actually measured by the second mass measuring instrument 7 is subtracted from the target value and the target value is reset (S22). Then, the process returns to S11. If the mass measured by the second mass measuring instrument 7 is, for example, around 3% of the target value, the operation is terminated.

[0042] On the other hand, in S16, if the mass of the powdery substance aspirated into the pipette tip 12 is less than the target value, the drive sources 18 and 29 are driven to insert the pipette tip 12 into the second container 40 and stop it while the powdery substance is contained in the pipette tip 12. At this time, the aspiration device 4 is operating. With the pipette tip 12 inserted into the second container 40, the powdery substance in the pipette tip 12 is discharged into the second container 40 by the discharge device 5 (S23). At this time, the three-way valve 33 connects the discharge passage 31 and the common passage 32, and the three-way valve 35 connects the first part 36 and the second part 37. Furthermore, when it is determined that the mass of the powdery substance drawn into the pipette tip 12 is less than the target value, the value obtained by subtracting the mass of the powdery substance remaining in the first mass measuring instrument 6 after it has been drawn into the pipette tip 12 from the mass of the powdery substance initially placed in the first mass measuring instrument 6 is compared with the target value.

[0043] The mass of the powdery material discharged into the second container 40 is measured by the second mass measuring instrument 7 (S21). If the mass measured by the second mass measuring instrument 7 is, for example, more than 5% of the target value, the mass actually measured by the second mass measuring instrument 7 is subtracted from the target value and the target value is reset (S22). Then, the process returns to S11. If the mass measured by the second mass measuring instrument 7 is, for example, around 3% of the target value, the operation is terminated.

[0044] Figure 7 is a flowchart showing another example of the operation method of the weighing device shown in Figure 1. In this example, steps S31 to S36 are the same as steps S11 to S16 shown in Figure 6. That is, from S31 to S36, the weighing device 1 is operated in the same way as in steps S11 to S16 shown in Figure 6.

[0045] In S36, the mass of the powder in the first container 38 is measured by the first mass measuring instrument 6. This is used to determine the mass of the powder drawn into the pipette tip 12. If the mass of the powder drawn into the pipette tip 12 is greater than the target value (the target mass measured by the second mass measuring instrument 7, described later), the weighing device 1 is operated as follows. When it is determined that the mass of the powder drawn into the pipette tip 12 is greater than the target value, the value obtained by subtracting the mass of the powder remaining in the first mass measuring instrument 6 after the powder has been drawn into the pipette tip 12 from the mass of the powder initially placed on the first mass measuring instrument 6 is compared with the target value. The mass of the powder initially placed on the first mass measuring instrument 6 may be measured by the first mass measuring instrument 6, or a powder of a predetermined mass may be used. The target value is predetermined. The suction device 4 is operating when the measurement is performed by the first mass measuring instrument 6.

[0046] Specifically, when a powdery substance is contained in the pipette tip 12, the pipette tip 12 is vibrated by the vibrator 8, and while a depressurization operation is performed by the suction device 4, the suction force adjustment means 10 is intermittently reduced (S37). In order to perform the depressurization operation by the suction device 4 and the suction force adjustment means 10 intermittently reduce the suction force, the suction force adjustment means 10 can be kept running to adjust the suction force, while the suction force adjustment means 10 gradually reduces the suction force. The suction force is reduced in stages, for example, at 5-second intervals. The number of times the suction force is reduced is set as appropriate. As a result, some of the powdery substance contained in the pipette tip 12 falls into the first container 38.

[0047] Subsequently, the mass of the powder in the first container 38 is measured by the first mass measuring instrument 6. This is used to determine the mass of the powder drawn into the pipette tip 12 (S38). If the mass of the powder drawn into the pipette tip 12 is greater than the target value, the process returns to S37. If the mass of the powder drawn into the pipette tip 12 is less than the target value, the suction device 4 is activated (S39). This prevents the powder in the pipette tip 12 from falling any further. When determining whether the mass of the powder drawn into the pipette tip 12 is greater than or less than the target value, the value obtained by subtracting the mass of the powder placed on the first mass measuring instrument 6 after it has fallen into the first container 38 from the mass of the powder initially placed on the first mass measuring instrument 6 is compared with the target value.

[0048] Then, with the powdery material contained in the pipette tip 12, the drive sources 18 and 29 are driven to insert the pipette tip 12 into the second container 40 and stop it. At this time, the aspiration device 4 is operating. With the pipette tip 12 inserted into the second container 40, the powdery material inside the pipette tip 12 is discharged into the second container 40 by the discharge device 5 (S40). At this time, the three-way valve 33 connects the discharge passage 31 and the common passage 32, and the three-way valve 35 connects the first part 36 and the second part 37.

[0049] The mass of the powdery material discharged into the second container 40 is measured by the second mass measuring instrument 7 (S41). If the mass measured by the second mass measuring instrument 7 is, for example, more than 5% of the target value, the mass actually measured by the second mass measuring instrument 7 is subtracted from the target value and the target value is reset (S42). Then, the process returns to S31. If the mass measured by the second mass measuring instrument 7 is, for example, around 3% of the target value, the operation is terminated.

[0050] On the other hand, in S36, if the mass of the powdery substance aspirated into the pipette tip 12 is less than the target value, the drive sources 18 and 29 are driven to insert the pipette tip 12 into the second container 40 and stop it while the powdery substance is contained in the pipette tip 12. At this time, the aspiration device 4 is operating. With the pipette tip 12 inserted into the second container 40, the powdery substance in the pipette tip 12 is discharged into the second container 40 by the discharge device 5 (S43). At this time, the three-way valve 33 connects the discharge passage 31 and the common passage 32, and the three-way valve 35 connects the first part 36 and the second part 37. Furthermore, when it is determined that the mass of the powdery substance drawn into the pipette tip 12 is less than the target value, the value obtained by subtracting the mass of the powdery substance remaining in the first mass measuring instrument 6 after it has been drawn into the pipette tip 12 from the mass of the powdery substance initially placed in the first mass measuring instrument 6 is compared with the target value.

[0051] The mass of the powdery material discharged into the second container 40 is measured by the second mass measuring instrument 7 (S41). If the mass measured by the second mass measuring instrument 7 is, for example, more than 5% of the target value, the mass actually measured by the second mass measuring instrument 7 is subtracted from the target value and the target value is reset (S42). Then, the process returns to S31. If the mass measured by the second mass measuring instrument 7 is, for example, around 3% of the target value, the operation is terminated.

[0052] In the weighing device 1 of this embodiment, the weighing device 1 has a first mass measuring instrument 6 and a second mass measuring instrument 7. Therefore, according to the weighing device 1 of this embodiment, powdery materials can be weighed easily and accurately.

[0053] In the case of the weighing device 1 of this embodiment, the weighing device 1 has a vibrator 8 and a pressure-recovering means 9. Therefore, according to the weighing device 1 of this embodiment, the powdery material in the pipette tip 12 can be dropped into the first container 38 with a simple configuration.

[0054] In the case of the weighing device 1 of this embodiment, the weighing device 1 has a vibrator 8 and a suction force adjustment means 10. Therefore, according to the weighing device 1 of this embodiment, powdery material in the pipette tip 12 can be dropped into the first container 38 with a simple configuration.

[0055] It should be noted that the present invention is not limited to the embodiments described above, and any modifications or improvements that can achieve the objectives of the present invention are included within the scope of the present invention.

[0056] For example, in the above embodiment, the measuring device 1 has a pressure-recovering means 9 and a suction force adjustment means 10, but it may also have only one of the pressure-recovering means 9 and the suction force adjustment means 10.

[0057] In the above embodiment, only one of the pressure-recovering means 9 and the suction force adjustment means 10 was activated, but both may be activated in combination. [Explanation of Symbols]

[0058] 1 Weighing device 2 nozzles 3 Support part 4 Suction device 5 Ejection device 6 First mass measuring device 7 Second mass measuring device 8 Vibrator 9. means of pressure restoration 10 Suction force adjustment means 12 pipette tips

Claims

1. A nozzle is provided on which a pipette tip, which is cylindrical and has a filter inside the middle of its axial position, can be detachably attached, The support portion on which the nozzle is supported, A suction device connected to the pipette tip via the nozzle, which aspirates air from inside the pipette tip, A discharge device connected to the pipette tip via the nozzle, which discharges air from inside the pipette tip to the outside, A first mass measuring instrument for measuring the mass of powdered material, The system comprises a second mass measuring device that measures the mass of powdered material transported from the first mass measuring device using the aforementioned suction device and discharge device, The first mass measuring device measures the mass of the powdery material after it has been sucked up by the suction device, before the powdery material is transported to the second mass measuring device.

2. A vibrator provided on the nozzle for vibrating the pipette tip, The measuring device according to claim 1, further comprising a means for restoring pressure to restore the inside of the pipette tip, which has been depressurized by the suction device, to atmospheric pressure.

3. The measuring device according to claim 2, wherein the pipette tip is vibrated by the vibrator, and the depressurization operation by the suction device and the repressurization operation by the repressurization means are repeated.

4. A vibrator provided on the nozzle for vibrating the pipette tip, The measuring device according to claim 1, further comprising a suction force adjusting means for reducing the suction force acting within the pipette tip by the suction device.

5. The measuring device according to claim 4, wherein the pipette tip is vibrated by the vibrator, and the suction force is intermittently reduced by the suction force adjustment means while the depressurization operation by the suction device is performed.

6. A vibrator provided on the nozzle for vibrating the pipette tip, A pressure-restoring means for restoring the pressure inside the pipette tip, which has been reduced by the suction device, to atmospheric pressure, The measuring device according to claim 1, further comprising a suction force adjusting means for reducing the suction force acting within the pipette tip by the suction device.

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