Electronic balance

Abstract

The present invention addresses the problem of providing an electronic balance in which the error factor of measurement is reduced to 0.1 mg or less before a user uses the electronic balance. The electronic balance comprises the following components: a balance body with a built-in load measuring mechanism part; a windshield disposed on an upper portion of the balance body, surrounding the weighing chamber, and including a door mechanism for opening and closing a door by a drive unit, and a static eliminator for eliminating static electricity in the weighing chamber; a timer unit that detects the arrival of the set time; and a control unit for controlling the opening and closing of the door and the operation of the static eliminator on the basis of the detection, the control unit opening the door on the basis of the detection by the timing unit, and closing the door and driving the static eliminator after a predetermined time has elapsed.

Description

[0001] This application is a divisional application of the original application number 202010079638.4, application date February 4, 2020 (priority date February 25, 2019), and the invention name is “Electronic Balance”. Technical Field

[0002] The invention relates to an electronic balance. Background Art

[0003] As a balance for precisely measuring the mass of various samples such as powders, an electromagnetic balance with a windshield (hereinafter referred to as an "electronic balance") is often used. The measurement is performed by installing a sample weighing unit in the windshield.

[0004] In order to improve operability, a balance with a windshield has been disclosed, in which the door opening and closing can be easily switched regardless of whether it is manual or automatic, the door opening and closing action is extremely smooth, and it can be manufactured cheaply (for example, Patent Document 1).

[0005] In addition, an electronic balance has been disclosed, which includes: a control element that generates a trigger signal at specified intervals or when a specified temperature change or a specified humidity change occurs; and a door opening and closing mechanism that automatically opens or closes the door through the trigger signal; and when the trigger signal is generated, the door is opened and closed to execute a convection time measurement mode (for example, Patent Document 2). The electronic balance receives the trigger signal, automatically opens the door of the wind shield, and automatically closes the door after a specified time, thereby generating convection in the wind shield that is the same as when it is performed manually. Soon, it is detected that the load change caused by the convection is within the specified range, and the time elapsed from closing the door to the end of the convection is updated as the convection time Tco. As described above, by automating the processing of the convection time measurement mode, the update of the convection time is forgotten, or the opening and closing actions of the door used to generate convection are unified, thereby eliminating deviations and improving the measurement accuracy.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Laid-Open No. 09-015031

[0009] Patent document 2: International Publication No. WO2006 / 082915 Summary of the invention

[0010] Problems to be solved by the invention

[0011] In an electronic balance with a weighing sensitivity of 0.1 mg or less, if the ambient temperature changes by more than 2° C. / hour, for example, convection increases in the weighing chamber, thereby affecting the weighing pan.

[0012] In addition, if the temperature difference between the weighing chamber and the inside of the frame increases, the internal weight ( weight ) and the temperature difference between the weighing room and the balance body will increase. Thus, when the temperature of the weighing room and the balance body is different, the air density in the weighing room and the balance body will be different, and the buoyancy of the object placed on the weighing pan and the calibration weight will be different, resulting in an error in the measured value.

[0013] In addition, if the flow of air in the weighing room caused by the opening and closing of the door of the wind shield or the temperature difference comes into contact with the glass wall forming the weighing room, static electricity will be generated on the glass surface, resulting in errors in sensitivity correction (adjustment) or measurement.

[0014] Regarding the above-mentioned problem, in Patent Document 2, the door is automatically opened or closed by a trigger signal generated at specified intervals or when a specified temperature change or a specified humidity change occurs, thereby suppressing the influence of convection. However, no content is disclosed regarding static electricity, and thus it is impossible to deal with errors in measurement caused by static electricity generated in the wind shield.

[0015] As one aspect, the present invention provides an electronic balance that reduces the measurement error factor below 0.1 mg before the user uses it.

[0016] Technical means of solving problems

[0017] An electronic balance according to one aspect of the present invention comprises: a balance body having a built-in load measuring mechanism; a wind shield arranged on the upper portion of the balance body, surrounding a weighing chamber, comprising a door mechanism and a static eliminator, wherein the door mechanism opens and closes the door through a driving unit, and the static eliminator removes static electricity in the weighing chamber; a timing unit for detecting the arrival of a set time; and a control unit for controlling the opening and closing of the door and the operation of the static eliminator based on the detection, wherein the control unit opens the door based on the detection of the timing unit, and closes the door after a specified time has passed, thereby driving the static eliminator.

[0018] The electronic balance further includes a humidity detection unit for measuring humidity, and the control unit drives the static elimination unit according to a measurement result obtained by the humidity detection unit and a setting of a user when the door is closed.

[0019] The balance also includes: a temperature detection unit for measuring temperature; and a setting unit for setting time, temperature change and humidity change; and the control unit controls the opening and closing of the door and the operation of the static remover based on the set time, the temperature change or the humidity change, and the detection results obtained by the timing unit, the humidity detection unit or the temperature detection unit.

[0020] Effects of the Invention

[0021] According to an aspect of the present invention, it is possible to reduce the measurement error factor of 0.1 mg or less before the user uses the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a perspective view showing an example of an electronic balance according to the present embodiment.

[0023] Figure 2 This is a block diagram showing a configuration example of an electronic balance main body according to Example 1 of the present embodiment.

[0024] Figure 3 This is a flowchart showing the door opening and closing and static elimination processing of the control unit of Example 1 of the present embodiment.

[0025] Figure 4 This is a block diagram showing a configuration example of an electronic balance body according to Example 2 of the present embodiment.

[0026] Figure 5 This is a flowchart showing the static elimination process of the control unit according to Example 2 of the present embodiment.

[0027] Explanation of symbols

[0028] 1: Electronic balance

[0029] 2: Windshield

[0030] 4: Electronic balance body

[0031] 5: Measuring plate

[0032] 6: Input section

[0033] 7: Display unit

[0034] 11: Weighing mechanism

[0035] 12: Door opening and closing mechanism

[0036] 13: Motor

[0037] 14: Static Eliminator

[0038] 15: Control Department

[0039] 16: Metrology Department

[0040] 17: Door opening and closing mechanism control unit

[0041] 18: Anti-static control unit

[0042] 19: Timer

[0043] 20: Memory

[0044] 31: Door opening and closing detection sensor

[0045] 32: Humidity sensor

[0046] 33: Temperature sensor DETAILED DESCRIPTION

[0047] Figure 1 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 by, for example, a top plate 2a, a left side wall 2b, a right side wall 2c, a front side wall 2d, and a rear side wall 2e. The top plate 2a, the left side wall 2b, the right side wall 2c, and the front side wall 2d are, for example, made of transparent glass or plastic. The rear side wall 2e is, for example, made of glass, metal, or plastic.

[0048] The top plate 2a, the left side wall 2b and the right side wall 2c are slidably mounted on rails, and are provided with handles 3a, 3b and 3c, respectively. The rails are provided on a frame constituting a windshield. When the handles 3a, 3b and 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, so that the sample can be placed on the measuring plate 5 of the electronic balance body 4.

[0049] As will be described later, the top plate 2a, the left side wall 2b, and the right side wall 2c can be slid by power and opened and closed automatically.

[0050] A weighing plate 5 is provided at the center of the upper part of the electronic balance body 4, on which a sample to be weighed can be placed. In addition, 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 to input instructions when the electronic balance 1 is operated, such as to start a weighing process or to start a calibration process. The display unit 7 displays a weighing result or a menu corresponding to an input made through the input unit 6.

[0051] Furthermore, in order to remove static electricity generated in the wind shield 2, a static eliminator (ionizer) is installed on the rear side wall 2e.

[0052] Figure 2The electronic balance body 4 includes a weighing mechanism 11, a door opening and closing mechanism 12, a neutralization unit 14, a control unit 15, a timer 19, and a memory 20 in an internal space partitioned by a metal frame.

[0053] The weighing mechanism 11 is an electromagnetic force balance part including a 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 lever. 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 become an electromagnet, and a rebound force / attraction force acts between the permanent magnet and the electromagnetic coil. The magnitude of the electromagnetic force varies according to the intensity of the current flowing into the electromagnetic coil.

[0054] 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 in such a way that the joystick does not displace. At this time, the greater the mass of the object to be measured, the greater the current value flowing into the electromagnetic coil, so the mass of the object to be measured can be measured based on the current value flowing into the electromagnetic coil.

[0055] The door opening and closing mechanism 12 is a mechanism that 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 wind shield 2. The door opening and closing mechanism 12 may also be a mechanism that includes a rack, for example, provided on the edges (edges) of the top plate 2a, the left side wall 2b, and the right side wall 2c that are parallel to the sliding direction, and a pinion provided on the motor 13 is used to move the rack in the sliding direction. In addition, the door opening and closing mechanism 12 may also include a speed reducer to obtain the required torque ( torque ) or speed.

[0056] In addition, when the motor 13 is not driven, the door opening and closing mechanism 12 may include a clutch mechanism so that the top plate 2a, the left side wall 2b, and the right side wall 2c can be opened and closed manually. It is also possible to disassemble one of the gears that mesh with each other in the power transmission system from the motor 13 to the pinion that drives the rack by the clutch mechanism. Thus, during the period when the gear is disassembled by the clutch mechanism, no load is applied to the power transmission system, so that the top plate 2a, the left side wall 2b, and the right side wall 2c can be opened and closed manually.

[0057] In addition, the door opening and closing mechanism 12 may be a mechanism in which, for example, a wire is fixed to 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 top plate 2a, the left side wall 2b, and the right side wall 2c are moved in the sliding direction along the track as a door by winding the wire with a motor. When the above structure is adopted, for example, it may be set as follows: two wires are fixed to the two ends of the side (edge), and when the door is opened, the wire fixed to one end of the side (edge) is wound by the first motor, and when the door is closed, the wire fixed to the other end of the side (edge) is wound by the second motor. In this case, the other motor that is not wound may be set as follows, that is, it is removed from the power transmission system so that no load is applied to the motor used for winding, and the shaft of the motor can rotate freely when not driven.

[0058] Furthermore, the door opening and closing mechanism 12 may also include a potentiometer or a position detection sensor, thereby adjusting the movement amount of the top plate 2a, the left side wall 2b, and the right side wall 2c in the sliding direction. In addition, a door opening and closing detection sensor may be provided on the electronic balance body 4, and the door opening and closing detection sensor detects whether the top plate 2a, the left side wall 2b, and the right side wall 2c are in a closed state. Furthermore, the door opening and closing mechanism 12 is an example and is not limited to these.

[0059] The control unit 15 is a processor that controls the operation of the entire electronic balance 1 , such as a central processing unit (CPU). The control unit 15 functions as a weighing unit 16 , a door opening and closing mechanism control unit 17 , and a neutralization control unit 18 .

[0060] The measuring unit 18 calculates the displacement of the other end of the joystick based on the detection signal detected by the optical position sensor in the weighing mechanism 11, and controls the magnitude of the current supplied to the electromagnetic coil so that the displacement of the other end of the joystick becomes 0. At the same time, the measuring unit performs the following control in a balanced state where the displacement of the other end of the joystick becomes 0: the load of the object to be measured placed on the measuring plate or the calibration weight placed on the calibration weight tray is obtained according to the magnitude of the current flowing into the electromagnetic coil.

[0061] The door opening and closing mechanism control unit 17 drives the motor 13 to operate the door opening and closing mechanism 12 to open and close the door (top plate 2a, left side wall 2b and right side wall 2c) based on a command set by a prescribed program or the arrival of a prescribed timing set by a timer (not shown), or a command from the input unit 6.

[0062] The memory 20 is a nonvolatile storage device such as a flash memory, and stores information such as measured values ​​and correction contents. The timer 19 measures date and time or time, or measures a fixed time.

[0063] Figure 3 1 is a flowchart showing the door opening and closing and static elimination processing of the control unit of Example 1 of this embodiment. The user sets the time to execute the processing applied to this embodiment in advance through the input unit. The set time information is stored in the memory 20.

[0064] The door opening and closing mechanism control unit 17 obtains the time information measured by the timer 19 (S1). The door opening and closing mechanism control unit 17 reads the time information from the memory 20, compares it with the time information from the timer 19, and determines whether the set time has arrived (S2). When the set time has not arrived (No in S2), the process returns to S1.

[0065] When it is determined that the set time has arrived (YES in S2), the door opening and closing mechanism control unit 17 drives the motor 13 in the direction of the door opening and slides the motor 13 so that the door is opened by a predetermined width (S3). When the door has been opened by the predetermined width, the door opening and closing mechanism control unit 17 stops driving the motor 13 (S4).

[0066] The door opening and closing mechanism control unit 17 waits in the state of S4 until the prescribed time T1 has passed (S5 is NO). When the prescribed time T1 has passed (S5 is YES), the door opening and closing mechanism control unit 17 drives the motor 13 in the direction of closing the door (S6). When the door is closed, the door opening and closing mechanism control unit 17 stops driving the motor 13 (S7).

[0067] In this process, when the static eliminator 14 is not operated (No in S8), the static eliminator 14 is operated (S9). The static eliminator 18 waits in the state of operating the static eliminator 14 until the prescribed time T2 has passed (No in S10). When the prescribed time T2 has passed (Yes in S10), the static eliminator 14 is stopped (S11).

[0068] After stopping the driving of the motor 13 in S7 , the static elimination control unit 18 waits until a predetermined time T3 elapses (NO in S12 , YES in S8 ).

[0069] After a predetermined time T3 has elapsed, this process ends (YES in S12 ).

[0070] Furthermore, Figure 3The flowchart shown in is an example of the process of this embodiment, and the present invention is not limited thereto. For example, the process from S3 onwards may be performed every time a fixed time has passed in S1 to S2.

[0071] Through Example 1, for example, the door can be opened for thirty minutes and then closed for five minutes, during which the static eliminator 24 is operated for one minute to remove static electricity generated by friction between the air flow and the glass such as convection. Thus, the following errors can be reduced before the user uses the device, namely, sensitivity adjustment error, convection error, and error caused by static electricity, which are error factors that are problematic in measurement of less than 0.1 mg. In particular, static electricity generated by convection in the wind shield 2 can be removed, so errors caused by static electricity can be reduced.

[0072] In addition, the static eliminator may be operated when the humidity or temperature around the electronic balance changes while the door is closed. This example will be described in the following embodiment 2.

[0073] Figure 4 This is a block diagram showing a configuration example of an electronic balance body according to Example 2 of the present embodiment. Figure 4 The electronic balance 1a is in Figure 2 The electronic balance 1 is provided with a door opening and closing detection sensor 31, a humidity sensor 32, and a temperature sensor 33. The door opening and closing detection sensor 31 is a sensor for detecting the opening and closing state of the door (top plate 2a, left side wall 2b, and right side wall 2c). The humidity sensor 32 is a sensor for measuring humidity. The temperature sensor 33 is a sensor for measuring temperature.

[0074] Figure 5 1 is a flowchart showing the static elimination process of the control unit of Example 2 of this embodiment. The user pre-sets the threshold value regarding humidity and the threshold value regarding temperature as condition information through the input unit 6. The set condition information is stored in the memory 20. In addition, the threshold value may be pre-set, for example, at the time of factory shipment.

[0075] When the door opening / closing detection sensor 31 detects that the door (top plate 2a, left wall 2b, and right wall 2c) is closed (YES in S21), the static control unit 18 obtains the measurement results from the humidity sensor 32 and / or the temperature sensor 33 (S22).

[0076] The static elimination control unit 18 reads the condition information from the memory 20, compares it with the measurement result from the humidity sensor 32 and / or the temperature sensor 33, and determines whether the measurement result satisfies the condition included in the condition information (S23). If the measurement result does not satisfy the condition (NO in S23), the process returns to S22.

[0077] When the measurement result satisfies the condition (YES in S23), the static elimination control unit 18 operates the static elimination 14 (S24). For example, when the humidity at the current time is lower than the threshold value set in the condition, or when the temperature at the current time is lower than the threshold value set in the condition, the static elimination control unit 18 operates the static elimination 14.

[0078] The static elimination control unit 18 operates the static elimination 14 for a predetermined time (NO in S25 , S24 ), and stops the static elimination 14 after the predetermined time has elapsed ( S26 ).

[0079] Through the second embodiment, the following errors can be reduced before the user uses the device, namely, the error factors that are problematic in the measurement of less than 0.1 mg, such as the sensitivity adjustment error, the convection error, and the error caused by static electricity. In particular, by focusing on humidity or temperature, even if static electricity is generated after the door is closed, the static electricity remover 14 can be operated to remove the static electricity, so the error caused by static electricity can be reduced.

[0080] As described above, the electronic balance of this embodiment (for example, the electronic balance 1, the electronic balance 1a) includes:

[0081] A balance body (e.g., an electronic balance body 4) having a load measuring mechanism built therein;

[0082] A windshield (e.g., windshield 2) is disposed on the upper part of the balance body, surrounds the weighing room, and includes a door mechanism (e.g., door opening and closing mechanism 12) and a static eliminator (e.g., static eliminator 14), wherein the door mechanism (e.g., door opening and closing mechanism 12) opens and closes the door (e.g., top plate 2a, left side wall 2b, and right side wall 2c) through a driving unit (e.g., motor 13), and the static eliminator (e.g., static eliminator 14) removes static electricity at the rear of the weighing room;

[0083] A timing unit (eg, timer 19) for detecting the arrival of a set time or a fixed timing; and

[0084] The control unit (for example, the control unit 15 ) controls the opening and closing of the door and the operation of the static eliminator based on the detection.

[0085] By configuring as described above, the error factor of measurement below 0.1 mg can be reduced before the user uses it. In particular, since static electricity generated by convection in the wind shield 2 can be removed, the error caused by static electricity can be reduced. In addition, the error factor can be eliminated before the user uses it, so the user can use the electronic balance immediately when he wants to use it, without having to wait for the time to eliminate the error factor.

[0086] The control unit opens the door based on the detection, and after a predetermined time has elapsed, closes the door to drive the static eliminating unit.

[0087] With the above configuration, errors such as sensitivity adjustment error, convection error, and error due to static electricity, which are error factors that are problematic in measurement of 0.1 mg or less, can be surely reduced before use by the user.

[0088] The electronic balance also includes:

[0089] A humidity detection unit (eg, humidity sensor 32) for measuring humidity; and

[0090] The control unit drives the static eliminator (for example, the static eliminator 14 ) according to the measurement result obtained by the humidity detector and the setting of the user when the door is closed.

[0091] With the above configuration, even when the humidity is high enough to generate static electricity after the door is closed, the static eliminator can be driven to remove static electricity, thereby reducing errors caused by static electricity before the user uses the device.

[0092] The balance also includes:

[0093] a temperature detection unit (eg, temperature sensor 33) for measuring temperature; and

[0094] A setting unit (e.g., input unit 6) for setting time, temperature change, and humidity change; and

[0095] The control unit (eg, control unit 15) controls the opening and closing of the door and the operation of the static eliminator based on the set time, the temperature change or the humidity change, and the detection result obtained by the timing unit, the humidity detection unit, or the temperature detection unit.

[0096] By configuring as described above, by presetting the time, temperature change, humidity change, etc., the door can be automatically opened and closed and the static elimination can be operated when the above conditions are met, so that the following errors can be reduced before the user uses the electronic balance, that is, the error factors that become a problem in the measurement of less than 0.1 mg, such as sensitivity adjustment error, convection error, and error caused by static electricity. Therefore, when the user uses the electronic balance, the user does not need to perform the operation of eliminating the error factors in advance, so the measurement operation can be performed efficiently.

[0097] The present embodiment has been described above based on the implementation mode and the modified example, but the implementation mode of the embodiment is used to make the present embodiment easy to understand, and does not limit the present embodiment. The present embodiment can be changed and improved without departing from its main purpose and claims, and includes its equivalent in the present embodiment. In addition, as long as the technical features are not described as essential features in this specification, they can be appropriately deleted.

Claims

1. An electronic balance, characterized in that: include: The balance body has a built-in load measuring mechanism; A windshield, arranged on the upper part of the balance body, surrounds the weighing chamber, and includes a door mechanism and a static eliminator, wherein the door mechanism opens and closes the door through a driving unit, and the static eliminator removes static electricity in the weighing chamber; a timing unit for detecting the arrival of a set time; and a control unit, based on the detection, controlling the opening and closing of the door and the operation of the static eliminator, The control unit opens the door based on the detection by the timer unit, and closes the door after a predetermined time has elapsed to drive the static eliminator.

2. The electronic balance according to claim 1, characterized in that: The electronic balance further comprises: a humidity detection unit for measuring humidity; and The control unit drives the static eliminator according to a measurement result obtained by the humidity detector and a setting of a user when the door is closed.

3. The electronic balance according to claim 2, characterized in that: The balance also includes: a temperature detection unit for measuring temperature; and A setting unit for setting time, temperature change and humidity change; and The control unit controls opening and closing of the door and operation of the static eliminator based on the set time, the temperature change or the humidity change, and a detection result obtained by the timer unit, the humidity detector, or the temperature detector.

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