CN111609910A

CN111609910A - Electronic balance

Info

Publication number: CN111609910A
Application number: CN202010079638.4A
Authority: CN
Inventors: 饭塚淳史
Original assignee: Shimadzu Corp
Current assignee: Shimadzu Corp
Priority date: 2019-02-25
Filing date: 2020-02-04
Publication date: 2020-09-01
Also published as: JP7099363B2; JP2020134452A

Abstract

The invention provides an electronic balance, which reduces error factors of metering below 0.1mg before a user uses the electronic balance. The electronic balance comprises the following components to solve the problem: a balance body having a load measuring mechanism section built therein; a windshield disposed on the upper part of the balance body, surrounding the weighing chamber, and including a door mechanism for opening and closing the door by a driving part and a static eliminator for eliminating static electricity at the rear of the weighing chamber; a timer unit for detecting arrival of a set time or a fixed time sequence; and a control unit that controls opening and closing of the door and operation of the electrical discharger based on the detection.

Description

Electronic balance

Technical Field

The present invention relates to an electronic balance.

Background

As a balance for precisely measuring the mass of various samples such as powder, an electromagnetic balance with a windshield (hereinafter, the electromagnetic balance is referred to as an "electronic balance") is often used, in which a sample weighing unit is provided in the windshield to perform measurement.

In order to improve operability, a balance with a windshield is disclosed, which can be easily switched between manual opening and closing and automatic opening and closing of a door, and which can be manufactured at low cost while the opening and closing of the door are extremely smooth (for example, patent document 1).

Further, there has been disclosed an electronic balance including: a control element for generating a trigger signal (trigger signal) at predetermined time intervals, or when a predetermined temperature change or a predetermined humidity change occurs; and a door opening and closing mechanism for automatically opening or closing the door by the trigger signal; when a trigger signal is generated, the convection time measurement mode is executed by opening and closing the door (for example, patent document 2). The electronic balance receives the trigger signal, automatically opens the door of the windshield, and automatically closes the door after a predetermined time has elapsed, thereby generating convection in the windshield as in the case of manual operation. After that, it is detected that the load change due to convection is within a predetermined range, and the elapsed time from the closing of the door to the end of convection is updated to the convection time Tco. As described above, by automating the process of the convection time measurement mode, the update of the convection time is forgotten, or the opening and closing operation of the door for generating convection is unified, so that the variation is eliminated, and the measurement accuracy is improved.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. Hei 09-015031

Patent document 2: international publication No. WO2006/082915

Disclosure of Invention

Problems to be solved by the invention

In an electronic balance having a metering sensitivity of 0.1mg or less, if, for example, the ambient temperature changes by more than 2 ℃/hour, convection increases in the weighing chamber, thereby affecting the metering disc.

Further, if the temperature difference between the weighing chamber and the inside of the housing increases, the temperature difference between the periphery of the built-in weight (weight) and the weighing chamber increases. Thus, when the temperatures in the weighing chamber and the balance body are different, the air densities in the weighing chamber and the balance body are different, and the buoyancy applied to the object to be weighed placed on the weighing pan and the calibration weight is different, thereby causing an error in the measured value.

Further, if the flow of air in the weighing chamber due to opening and closing of the door of the windshield cover, the temperature difference, or the like comes into contact with the glass wall surface forming the weighing chamber, static electricity is generated on the glass surface, and an error occurs in correction (adjustment) of sensitivity or measurement.

In the patent document 2, the influence of convection is suppressed by automatically opening or closing the door at predetermined time intervals or by generating a trigger signal generated when a predetermined temperature change or a predetermined humidity change occurs, but nothing is disclosed about static electricity, and an error in measurement due to static electricity generated in the windshield cannot be dealt with.

In one aspect, the present invention provides an electronic balance that reduces the error factor of metering of 0.1mg or less before use by a user.

Means for solving the problems

An electronic balance of an aspect of the present invention is characterized by comprising: a balance body having a load measuring mechanism section built therein; a windshield provided on an upper portion of the balance body, surrounding the weighing chamber, and including a door mechanism that opens and closes a door by a driving portion and a static eliminator that eliminates static electricity behind the weighing chamber; a timer unit for detecting arrival of a set time or a fixed time sequence; and a control unit that controls opening and closing of the door and operation of the electrical discharger based on the detection.

The control unit opens the door based on the detection, closes the door after a predetermined time has elapsed, and drives the charge removing unit.

The electronic balance is characterized by further comprising a humidity detection part for measuring humidity, and the control part drives the electricity removal part according to the measurement result obtained by the humidity detection part and the setting of a user when the door is closed.

The balance is characterized by further comprising: a temperature detection unit for measuring a temperature; and a setting unit for setting the time, temperature change and humidity change; and the control unit controls opening and closing of the door and operation of the power remover based on the set time, the temperature change or the humidity change, and a detection result obtained by the timer unit, the humidity detection unit, or the temperature detection unit.

ADVANTAGEOUS EFFECTS OF INVENTION

According to an aspect of the present invention, it is possible to reduce the error factor of the metering of 0.1mg or less before the user uses it.

Drawings

Fig. 1 is a perspective view showing an example of an electronic balance according to the present embodiment.

Fig. 2 is a block diagram showing a configuration example of the electronic balance body of example 1 of the present embodiment.

Fig. 3 is a flowchart showing the door opening/closing and charge removing process of the control unit in example 1 of the present embodiment.

Fig. 4 is a block diagram showing a configuration example of the electronic balance main body of example 2 of the present embodiment.

Fig. 5 is a flowchart showing a charge removal process of the control unit in example 2 of the present embodiment.

Description of the symbols

1: electronic balance

2: wind-proof cover

4: electronic balance body

5: metering disc

6: input unit

7: display unit

11: weighing mechanism

12: door opening and closing mechanism

13: motor with a stator having a stator core

14: electricity eliminator

15: control unit

16: measuring part

17: door opening and closing mechanism control unit

18: charge removing control unit

19: timer

20: memory device

31: door opening and closing detection sensor

32: humidity sensor

33: temperature sensor

Detailed Description

Fig. 1 is a perspective view showing an example of an electronic balance according to the present embodiment. The electronic balance 1 includes a windshield 2 and an electronic balance body 4. The windshield 2 is formed of, for example, a ceiling 2a, a left side wall 2b, a right side wall 2c, a front side wall 2d, and a rear side wall 2 e. The top plate 2a, the left side wall 2b, the right side wall 2c, and the front side wall 2d are made of, for example, transparent glass or plastic (plastic). The rear side wall 2e is made of, for example, glass, metal, or plastic.

The top plate 2a, the left side wall 2b, and the right side wall 2c are slidably attached to rails (rails) provided on a frame constituting the windshield, and are provided with a handle 3a, a handle 3b, and a handle 3c, respectively. When the handle 3a, the handle 3b, and the handle 3c are slid toward the rear side wall 2e, the top plate 2a, the left side wall 2b, and the right side wall 2c also slide as doors, and the sample can be placed on the measuring pan 5 of the electronic balance main body 4.

As will be described later, the top panel 2a, the left side wall 2b, and the right side wall 2c can slide by power to be automatically opened and closed.

A measuring pan 5 is provided at the center of the upper portion of the electronic balance body 4, and a sample to be measured can be placed thereon. Further, an input unit 6 and a display unit 7 are provided on the front surface of the electronic balance body 4. The input unit 6 is used when an instruction to start measurement is given or when an instruction is input to operate the electronic balance 1, such as when calibration processing is started. The display unit 7 displays a measurement result, a menu (menu) corresponding to an input through the input unit 6, and the like.

In addition, a static electricity remover (ionizer) is attached to the rear side wall 2e to remove static electricity generated in the windshield 2.

Fig. 2 is a block diagram showing a configuration example of the electronic balance body of example 1 of the present embodiment. The electronic balance body 4 includes a weighing mechanism 11, a door opening/closing mechanism 12, a static elimination unit 14, a control unit 15, a timer 19, and a memory 20 in an internal space partitioned by a metal frame.

The weighing means 11 is an electromagnetic force balancing unit including a lever (lever), a fulcrum, an electromagnetic coil (force coil), and a permanent magnet. The electromagnetic coil is a movable electromagnetic coil of an electromagnetic force generating device fixed to the other end of the joystick. The permanent magnet is fixed to the metal frame of the electronic balance body 4. When current flows into the electromagnetic coil, a magnetic field is generated to act as an electromagnet, and a repulsive force/attractive force acts between the electromagnet and the permanent magnet. The magnitude of the electromagnetic force varies depending on the intensity of the current flowing into the electromagnetic coil.

When measuring the mass of the object, the displacement of the joystick is detected by the displacement detector, and the current flowing into the electromagnetic coil is feedback-controlled so that the joystick does not displace. In this case, the larger the mass of the object to be measured, the larger the current value flowing into the electromagnetic coil, and therefore the mass of the object to be measured can be measured based on the current value flowing into the electromagnetic coil.

The door opening/closing mechanism 12 includes a motor 13 and opens and closes the top plate 2a, the left side wall 2b, and the right side wall 2c of the windshield 2. The door opening/closing mechanism 12 may be as follows: for example, a rack (rack) is provided on the side (edge) of the top plate 2a, the left side wall 2b, and the right side wall 2c that is horizontal to the sliding direction, and the rack is moved in the sliding direction by a pinion (pinion) provided on the motor 13. The door opening/closing mechanism 12 may include a speed reducer to obtain a required torque (torque) or rotation speed from the motor 13.

When the motor 13 is not driven, the door opening/closing mechanism 12 may include a clutch (clutch) mechanism so that the top plate 2a, the left side wall 2b, and the right side wall 2c can be manually opened and closed. One of gears (gear) engaged with each other in a power transmission system from the motor 13 to a pinion gear for driving the rack may be removed by a clutch mechanism. Thus, since a load is not applied to the power transmission system while the gears are removed by the clutch mechanism, the top plate 2a, the left side wall 2b, and the right side wall 2c can be opened and closed manually.

The door opening/closing mechanism 12 may be configured as follows: wires (wires) are fixed to the sides (edges) of the top plate 2a, the left side wall 2b, and the right side wall 2c that are horizontal to the sliding direction, and the wires are wound around by a motor, whereby the top plate 2a, the left side wall 2b, and the right side wall 2c move as doors along the rails in the sliding direction. When the above configuration is adopted, for example, it is also possible to provide: the two metal wires are respectively fixed at two ends of the edge (edge), when the door is opened, the first motor is used for winding and fixing the metal wires at one end of the edge (edge), and when the door is closed, the second motor is used for winding and fixing the metal wires at the other end of the edge (edge). In this case, the other motor that is not wound may be configured to be detached from the power transmission system so as not to apply a load to the motor used for winding, or the shaft of the motor may be configured to be rotatable when not driven.

The door opening/closing mechanism 12 may include a potentiometer (potentiometer), a position detection sensor, and the like, and may adjust the amount of movement of the top plate 2a, the left side wall 2b, and the right side wall 2c in the sliding direction. Further, a door opening/closing detection sensor that detects whether or not the top plate 2a, the left side wall 2b, and the right side wall 2c are in the closed state may be provided in the electronic balance body 4. The door opening/closing mechanism 12 is an example, and is not limited to these.

The control unit 15 is a processor that controls the operation of the entire electronic balance 1, and is, for example, a Central Processing Unit (CPU). The controller 15 functions as a metering unit 16, a door opening/closing mechanism controller 17, and a charge removal controller 18.

The measuring unit 18 calculates the displacement of the other end portion of the joystick based on the detection signal detected by the optical position sensor in the weighing mechanism 11, and performs control for determining the magnitude of the current supplied to the electromagnetic coil so that the displacement of the other end portion of the joystick becomes 0. At the same time, the measuring section performs the following control in a balanced state in which the displacement of the other end portion of the joystick becomes 0: the load of the object to be measured placed on the measuring tray or the calibration weight placed on the calibration weight tray is determined based on the magnitude of the current flowing into the electromagnetic coil.

The door opening/closing mechanism control unit 17 drives the motor 13 to operate the door opening/closing mechanism 12 to open and close the doors (the ceiling 2a, the left side wall 2b, and the right side wall 2c) based on a command set by a predetermined program, arrival of a predetermined time sequence set by a timer (not shown), a command from the input unit 6, or the like.

The memory 20 is a nonvolatile storage device such as a flash memory (flash memory) and stores information such as a measurement value and correction content. The timer 19 measures the date and time or the time of day, or measures a fixed time.

Fig. 3 is a flowchart showing the door opening/closing and charge removing process of the control unit in example 1 of the present embodiment. The user sets in advance the timing of executing the processing according to the present embodiment through the input unit. The set time information is stored in the memory 20.

The door opening/closing mechanism control unit 17 acquires the time information measured by the timer 19 (S1). The door opening/closing mechanism control unit 17 reads the time information from the memory 20, compares the time information with the time information from the timer 19, and determines whether or not the set time has come (S2). If the set time has not come (NO in S2), the process returns to S1.

When it is determined that the set time has come (YES in S2), the door opening/closing mechanism control unit 17 drives the motor 13 in the door opening direction and slides the motor to open the door by a predetermined width (S3). When the door is opened by a predetermined width, the door opening/closing mechanism control unit 17 stops the driving of the motor 13 (S4).

The door opening/closing mechanism control unit 17 waits in the state of S4 until the predetermined time T1 elapses (NO in S5). When the predetermined time T1 has elapsed (YES in S5), the door opening/closing mechanism control unit 17 drives the motor 13 in the door closing direction (S6). When the door is closed, the door opening/closing mechanism control unit 17 stops the driving of the motor 13 (S7).

In this flow, the neutralization control unit 18 does not operate the neutralizer 14 (NO in S8), and operates the neutralizer 14 (S9). The neutralization control unit 18 waits until the predetermined time T2 elapses while the neutralizer 14 is operated (NO in S10). When the predetermined time T2 has elapsed (YES in S10), the neutralization control unit 18 stops the operation of the neutralizer 14 (S11).

The neutralization control unit 18 stops the driving of the motor 13 in S7 and then waits until a predetermined time T3 elapses (NO in S12 and YES in S8).

After the predetermined time T3 has elapsed, the present process is ended (YES in S12).

The flowchart shown in fig. 3 is an example of the processing of the present embodiment, and is not limited to this. For example, the processing of S3 or more may be performed every time a fixed time period elapses in S1 to S2.

In example 1, for example, the door can be opened for thirty minutes and then closed for five minutes, and the static electricity generated by the friction between the glass and the flow of air such as convection can be removed by operating the static eliminator 24 for one minute. This makes it possible to reduce errors caused by measurement of 0.1mg or less, such as sensitivity adjustment errors, convection errors, and errors due to static electricity, before use by the user. In particular, since static electricity generated by convection in the wind shield 2 can be removed, an error caused by the static electricity can be reduced.

In addition, the static eliminator may be operated when the humidity or temperature around the electronic balance is changed in a state where the door is closed. In example 2 below, the example is illustrated.

Fig. 4 is a block diagram showing a configuration example of the electronic balance main body of example 2 of the present embodiment. The electronic balance 1a of fig. 4 is a balance in which a door open/close detection sensor 31, a humidity sensor 32, and a temperature sensor 33 are added to the electronic balance 1 of fig. 2. The door opening/closing detection sensor 31 is a sensor for detecting the open/closed state of the doors (the ceiling 2a, the left wall 2b, and the right wall 2 c). The humidity sensor 32 is a sensor that measures humidity. The temperature sensor 33 is a sensor that measures temperature.

Fig. 5 is a flowchart showing a charge removal process of the control unit in example 2 of the present embodiment. The user sets a threshold value for humidity and a threshold value for temperature as condition information in advance through the input unit 6. The set condition information is stored in the memory 20. The threshold value may be set in advance at the time of factory shipment, for example.

When the door opening/closing detection sensor 31 detects that the doors (the ceiling 2a, the left side wall 2b, and the right side wall 2c) are closed (YES in S21), the neutralization control unit 18 acquires the measurement results from the humidity sensor 32 and/or the temperature sensor 33 (S22).

The neutralization control unit 18 reads the condition information from the memory 20, compares the condition information with the measurement results from the humidity sensor 32 and/or the temperature sensor 33, and determines whether or not the measurement results satisfy the conditions included in the condition information (S23). When the measurement result does not satisfy the condition (NO in S23), the process returns to S22.

When the measurement result satisfies the condition (YES in S23), the neutralization control unit 18 operates the neutralizer 14 (S24). For example, the neutralization control unit 18 operates the neutralizer 14 when the humidity at the present time is lower than a threshold set under the condition, or when the temperature at the present time is lower than a threshold set under the condition.

The neutralization control unit 18 operates the neutralizer 14 for a predetermined time (NO in S25, S24), and stops the neutralizer 14 after the predetermined time has elapsed (S26).

In example 2, among error factors that become problems in measurement of 0.l mg or less, a sensitivity adjustment error, a convection error, and an error due to static electricity can be reduced before use by a user. In particular, even if static electricity is generated after the door is closed by focusing attention on humidity or temperature, the static electricity remover 14 can be operated to remove the static electricity, so that an error due to the static electricity can be reduced.

As described above, the electronic balance (e.g., electronic balance 1a) of the present embodiment includes:

a scale body (e.g., electronic scale body 4) having a load measuring mechanism portion built therein;

a windshield (e.g., windshield 2) disposed above the balance body, surrounding the weighing chamber, and including a door mechanism (e.g., door opening/closing mechanism 12) that opens and closes doors (e.g., top plate 2a, left side wall 2b, and right side wall 2c) by a driving unit (e.g., motor 13) and a static eliminator (e.g., static eliminator 14) that eliminates static electricity behind the weighing chamber;

a timer unit (e.g., a timer 19) that detects arrival of a set time or a fixed time sequence; and

and a control unit (for example, a control unit 15) that controls opening and closing of the door and operation of the electrical discharger based on the detection.

With the above configuration, the error factor of the measurement of 0.1mg or less can be reduced before the user uses the device. In particular, since static electricity generated by convection in the wind shield 2 can be removed, an error caused by the static electricity can be reduced. In addition, since the error factor can be eliminated before the user uses the electronic device, the user can use the electronic device immediately when the user wants to use the electronic device, and does not need to wait for the time for eliminating the error factor.

With the above configuration, errors such as sensitivity adjustment errors, convection errors, and errors due to static electricity among error factors that become a problem in measurement of 0.1mg or less can be reduced reliably before use by the user.

The electronic balance further includes:

a humidity detection part (for example, a humidity sensor 32) that measures humidity; and is

The control unit drives the electricity removing unit (for example, the electricity remover 14) based on the measurement result obtained by the humidity detecting unit and the setting of the user when the door is closed.

With the above configuration, even when the humidity becomes a humidity at which static electricity is likely to be generated after the door is closed, the static electricity can be removed by driving the static electricity remover, and therefore, errors due to static electricity can be reduced before the user uses the door.

The balance further comprises:

a temperature detection section (e.g., temperature sensor 33) that measures temperature; and

a setting unit (e.g., input unit 6) for setting the time, temperature change, and humidity change; and is

The control unit (for example, the control unit 15) controls opening and closing of the door and operation of the electricity remover based on the set time, the temperature change or the humidity change, and the detection result obtained by the timer unit, the humidity detection unit, or the temperature detection unit.

With the above configuration, since the door can be automatically opened and closed and the static eliminator can be operated when the conditions are satisfied by setting the time, temperature change, humidity change, and the like in advance, errors such as a sensitivity adjustment error, a convection error, and an error due to static electricity among error factors that become problems in measurement of 0.1mg or less can be reduced before use by a user. Therefore, when the user uses the electronic balance, the user does not need to perform the operation of eliminating the error factor in advance, and the measuring operation can be performed efficiently.

The present embodiment has been described above based on the embodiments and the modified examples, but the embodiments of the embodiments are for facilitating understanding of the present embodiment, and are not intended to limit the present embodiment. The present embodiment can be modified and improved without departing from the gist and the claims, and the present embodiment includes equivalents thereof. In addition, as long as the technical features are not described as essential features in the present specification, the technical features can be appropriately deleted.

Claims

1. An electronic balance, comprising:

a balance body having a load measuring mechanism section built therein;

a windshield provided on an upper portion of the balance body, surrounding the weighing chamber, and including a door mechanism that opens and closes a door by a driving unit and a static eliminator that eliminates static electricity in the weighing chamber;

a timer unit for detecting arrival of a set time or a fixed time sequence; and

and a control unit for controlling the opening and closing of the door and the operation of the power remover based on the detection.

2. The electronic balance according to claim 1,

3. The electronic balance according to claim 1 or 2,

the electronic balance further includes:

a humidity detection unit for measuring humidity; and is

The control unit drives the charge removing unit based on the measurement result obtained by the humidity detecting unit and the setting of the user when the door is closed.

4. The electronic balance according to claim 3,

the balance further comprises:

a temperature detection unit for measuring a temperature; and

a setting unit for setting time, temperature change and humidity change; and is

The control unit controls opening and closing of the door and operation of the power remover based on the set time, the temperature change or the humidity change, and the detection result obtained by the timer unit, the humidity detector, or the temperature detector.