JP6160746B2 - Electronic balance and method of use - Google Patents

Description

  The present invention relates to an electronic balance provided with a windshield for preventing the influence of airflow and a method for using the same, and to an electronic balance for eliminating static electricity inside the windshield.

  In a laboratory or the like, an electronic balance is used to weigh an object to be measured such as powder. At this time, the measurer confirms the displayed measurement result while placing the object to be measured using a spoon or the like on the placing surface of the weighing pan formed on the upper surface of the electronic balance. The target weight to be measured is obtained. However, the measurement results may not be stable due to the influence of airflow blown out from the air conditioner installed indoors.

Therefore, an electronic balance provided with a windshield for preventing the influence of airflow is disclosed. FIG. 6 is a plan view illustrating an example of an electronic balance including a windshield, and FIGS. 7 and 8 are side views illustrating an opening / closing member of the windshield of the electronic balance illustrated in FIG. 6.
The electronic balance 201 is an electronic balance body including a weighing pan 40, a weighing mechanism (not shown), a control unit (not shown), an input unit 41, a display unit 42, and a built-in weight (not shown) for sensitivity calibration. 210, a windshield 220 that prevents the influence of airflow, and a timer (clock, not shown) that measures time.

  The electronic balance body 210 includes a flat housing 10a, an input unit 41 and a display unit 42 provided on the front side of the upper surface of the housing 10a, a weighing pan 40 provided at the center of the upper surface of the housing 10a, a housing A weighing mechanism, a control unit, and a built-in weight housed in 10a. The weighing dish 40 has, for example, a circular mounting surface having a diameter of 8 to 9 cm when viewed from above. As a result, the object to be measured is placed on the placement surface.

The windshield 220 includes four front side walls 30a made of glass, a rear side wall 230b made of glass, metal or plastic, and four corners formed in parallel with each other between the four corners of the front side wall 30a and the four corners of the rear side wall 230b. A frame (side wall) 30 having a guide pillar portion 30c, a glass square upper opening opening / closing member 21, a glass square right opening opening / closing member 22, and a glass square left opening Part opening / closing member 23.
The four guide pillars 30c are formed with grooves that allow the upper opening / closing member 21, the right opening / closing member 22, and the left opening / closing member 23 to slide in the front-rear direction. When the left and right ends of the upper opening / closing member 21 are inserted, the upper opening / closing member 21 is attached to the upper surface of the frame 30 so as to be movable in the front-rear direction. By inserting the upper and lower ends, the right opening opening / closing member 22 is attached to the right side surface of the frame 30 so as to be movable in the front-rear direction, and the upper and lower ends of the left opening opening / closing member 23 are inserted. Thus, the left opening opening / closing member 23 is attached to the left side surface of the frame 30 so as to be movable in the front-rear direction.
The upper opening / closing member 21 is attached to the upper surface of the frame body 30 to serve as an upper wall.

  As a result, the measurer slides the upper opening / closing member 21 backward to open the upper opening of the frame 30 as shown in FIG. 8 or slide it forward as shown in FIG. Thus, the upper opening can be closed. Also, the right opening opening / closing member 22 is slid rearward to open the right opening of the frame 30 as shown in FIG. 8, or the right opening is slid forward as shown in FIG. Can be closed. Furthermore, by sliding the left opening opening / closing member 23 backward, the left opening of the frame 30 can be opened, or the left opening can be closed by sliding forward. Yes. There is also a windshield that opens and closes automatically when driven by a motor.

  By placing such a windshield 220 on the electronic balance body 210 from above, the weighing pan 40 is disposed inside the windshield 220. Then, for example, the measurer slides the right opening opening / closing member 22 backward to open the right opening and the like, thereby using a spoon or the like at the center of the mounting surface of the weighing pan 40 to be measured. After the object is placed and the object to be measured is placed on the weighing pan 40, the right opening opening / closing member 22 is slid forward to close the right opening and the like. Check the measurement results.

However, when the object to be measured is charged, a Coulomb force due to electrostatic induction is generated between the object to be measured and the windshield 220, and the measurement result includes an error with respect to the original mass of the object to be measured. Become. For example, in a clean room where the humidity is set to 20 to 30% or less in order to maintain a low-humidity environment such as the Pacific region in winter or to suppress the propagation of viruses and bacteria, the object to be measured A weighing error of several tens of mg may occur due to charging.
Therefore, in order to avoid the influence of static electricity, static electricity is neutralized and reduced by spraying ions on a charged object to be measured using a static elimination function (see, for example, Patent Document 1).

JP 2010-190600 A

  However, not only the static electricity of the object to be measured but also the static electricity of the windshield 220 itself may be a problem. Further, in the electronic balance 201, a change in electromagnetic force (influence of a change in temperature of the magnetic flux density) that balances with the load of the object to be measured due to a change in temperature or the like, a slight expansion / contraction of the weighing mechanism, etc. occur. An error is generated. For this reason, it is necessary to calibrate the sensitivity using the built-in weight so that no error occurs in the measurement result. Therefore, the sensitivity calibration is automatically performed as appropriate by the operator's operation of the input unit 41 or the like, or automatically by a signal from a temperature sensor or the like. At this time, if the windshield 220 is charged, a Coulomb force due to electrostatic induction is generated, and there is a problem that an error is included in the calibration content itself.

  Therefore, the applicant examined a method for reducing static electricity inside the windshield of the electronic balance. As a result, they found that a static eliminator (ionizer) was installed inside the windshield. However, if a static eliminator is installed inside the windshield, it will take extra time and effort to operate the static eliminator, and it is possible to operate the static eliminator for those that are automatically calibrated. However, the calibration content itself contained errors. Therefore, the present inventors have found that the static eliminator is operated automatically and at an appropriate time by the control unit.

  That is, the electronic balance of the present invention includes an electronic balance body having a weighing pan, a weighing mechanism, a control unit, an input unit, and a display unit, and a windshield, and the windshield is disposed on the electronic balance body from above. An electronic balance in which a weighing pan is arranged inside the windshield, comprising a static eliminator and a clock for measuring time, and the static eliminator attached to the inside of the windshield is controlled by the control unit. When the static elimination start scheduled time and the static elimination end scheduled time are input at the input unit, the control unit operates the static eliminator at the scheduled static elimination start time and ends the static elimination The operation of the static eliminator is terminated at a scheduled time.

According to the electronic balance of the present invention, static electricity inside the windshield can be reduced by the static eliminator. In addition, since static elimination can be performed when not in use (for example, a break time), the weighing operation can be started smoothly. Note that a predetermined time for operating the static eliminator may be input instead of the scheduled static elimination end time.
Here, the “predetermined time” is an arbitrary time determined in advance by a measurer or the like, and is, for example, 30 seconds to 10 minutes.

(Means and effects for solving other problems)
In the above invention, the windshield has an upper wall and a side wall provided downward from a peripheral edge of the upper wall, and the upper wall or the side wall opens and closes the opening and the opening. An opening opening / closing member that can be made may be formed.
In the above invention, the static eliminator may be removable from the inside of the windshield.
In the above invention, the static eliminator may include a voltage generator and an ion generation electrode that generates ions when a voltage is applied by the voltage generator.
Furthermore, in the above invention, the ion generation electrode may generate positive ions and negative ions.

  And the method of using the electronic balance of the present invention comprises an electronic balance body having a weighing pan, a weighing mechanism, a control unit, an input unit, and a display unit, a windshield, a static eliminator, and a clock for measuring time, By arranging the windshield on the electronic balance main body from above, a weighing pan is arranged inside the windshield, and the static eliminator attached to the inside of the windshield can be controlled by the control unit. A method of using the electronic balance, the step of placing an object to be measured inside the windshield, the step of inputting a scheduled static elimination start time and a scheduled static termination end time at the input unit, and the control unit Includes a step of operating the static eliminator at the scheduled start time for static elimination and ending the operation of the static eliminator at the scheduled time for termination of static elimination.

The top view which shows an example of the electronic balance which is one Embodiment of this invention. The side view shown in FIG. The block diagram of the electronic balance shown in FIG. The top view which shows an example of an ionizer. The bottom view which shows an example of an ionizer. The top view which shows an example of an electronic balance provided with a windshield. The side view explaining the opening part opening-closing member of the windshield of the electronic balance shown in FIG. The side view similar to FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments described below, and it goes without saying that various aspects are included without departing from the spirit of the present invention.

FIG. 1 is a plan view showing an example of an electronic balance according to an embodiment of the present invention, and FIG. 2 is a side view shown in FIG. FIG. 3 is a block diagram of the electronic balance shown in FIG. In addition, the same code | symbol is attached | subjected about the thing similar to the conventional electronic balance 201 mentioned above.
The electronic balance 101 includes an electronic balance main body 110 having a weighing pan 40, a weighing mechanism 80, a control unit 150, an input unit 41, and a display unit 42, a windshield 20 that prevents the influence of airflow, and a timer (clock) that measures time. ) 45 and an ionizer (static eliminator) 60.

  Here, FIG. 4 is a plan view showing an example of the ionizer 60, and FIG. 5 is a bottom view showing an example of the ionizer 60. The ionizer 60 has a rectangular parallelepiped housing 70, and a switch 73 for controlling the high voltage generator, an intake port 71, and a discharge port 72 are formed in the housing 70. Although not shown, the housing 70 includes a high voltage generator, an ion generation electrode that generates ions when a voltage is applied, and a fan that blows air.

  The air inlet 71 is disposed on the upper surface of the housing 70, and is a square opening of 30 mm × 30 mm in plan view, for example, and a dust removing filter (not shown) having a mesh size of about 1.5 mm square. Is installed. Further, the discharge port 72 is disposed on the lower surface of the housing 70, and is a square opening of 30 mm × 30 mm when viewed in plan, for example.

The fan is for creating a flow of air, and for example, a small fan having an air volume of about 0.04 m ³ / min. Thus, when the fan rotates, an air flow is generated from the intake port 71 to the discharge port 72.
The high voltage generator boosts the input voltage applied between the + input lead wire and the − input lead wire with a piezoelectric transformer, converts the input voltage into an alternating current, and outputs the alternating voltage.

  The ion generation electrode forms a needle end and is a needle-like electrode facing the discharge port 72. Thereby, an alternating voltage is applied by a high voltage output line, and negative ions and positive ions are generated alternately. The grounding electrode is also formed with a needle end that faces the discharge port 72. Since the ion generating electrode and the ground electrode are disposed between the intake port 71 and the discharge port 72 and are disposed downstream of the fan, the ions from the discharge port 72 are blown by the air blown from the fan. The contained air will be released.

  According to such an ionizer 60, the measurer turns on the switch 73 to apply the input voltage to the high voltage generator, so that the electric field is concentrated on the tip of the ion generating electrode and the corona is placed on the tip. Discharge occurs. As a result, ions are generated from the ion generating electrode. The ions generated in this manner are sprayed onto an object (measurement object or the like) with a fan, so that static electricity of the object can be neutralized and reduced.

The windshield 20 includes four front side walls 30a made of glass, a rear side wall 30b made of glass, metal or plastic, and four sides formed in parallel with each other between the four corners of the front side wall 30a and the four corners of the rear side wall 30b. A frame (side wall) 30 having a guide pillar portion 30c, a glass square upper opening opening / closing member 21, a glass square right opening opening / closing member 22, and a glass square left opening Part opening / closing member 23.
A static eliminator mounting portion 31 is formed in the central portion of the front surface of the rear side wall 30b as a concave portion to which the ionizer 60 can be attached and detached. Thus, the measurer can attach the ionizer 60 to the static eliminator attachment portion 31 by inserting the upper surface of the housing 70 of the ionizer 60 toward the front surface of the rear side wall 30b. When the ionizer 60 is attached to the static eliminator attachment portion 31, the control unit 150 of the electronic balance body 110 can control ON / OFF of the switch 73. When the switch 73 is turned on, ions generated by the ionizer 60 are attracted to the charged windshield 20 and the like, so that static electricity from the windshield 20 and the like can be neutralized and reduced. Further, the measurer can remove the ionizer 60 from the static eliminator mounting portion 31 by pulling out the ionizer 60 from the static eliminator mounting portion 31.

  The weighing mechanism 80 includes a lever 84 that is swingably supported by a fulcrum 88, a movable electromagnetic coil 87 of an electromagnetic force generator fixed to the other end of the lever 84, and a permanent magnet 86 fixed to the housing 10a. The optical position sensor 85 fixed to the housing 10a so as to detect the position of the other end of the lever 84, the temperature sensor 44 for detecting the temperature of the permanent magnet 86, and the temperature sensor for detecting the temperature of the lever 84 ( (Not shown).

  The control unit 150 includes a CPU 151 and a memory 46, and the functions processed by the CPU 151 will be described as a block. Explaining that the control unit 150 controls the ON / OFF of the switch 73 of the ionizer 60 based on the input signal input from the input unit 41. It has the electric appliance control part 151a and the measurement part 51d which measures.

  The weighing unit 51d calculates the displacement of the other end of the lever 84 based on the detection signal detected by the optical position sensor 85, and moves the movable electromagnetic so that the displacement of the other end of the lever 84 becomes zero. The magnitude of the current supplied to the coil 87 is determined and, in an equilibrium state where the displacement of the other end of the lever 84 is zero, the object placed on the weighing pan 40 is determined from the magnitude of the current flowing through the movable electromagnetic coil 87. Control for obtaining the load of the measuring object S is performed.

  The static eliminator control unit 151 a controls ON / OFF of the switch 73 of the ionizer 60 based on the input signal input from the input unit 41. Specifically, when a static elimination start time signal (for example, 12:45) and a static elimination end time signal (for example, 12:55) are received from the input unit 41, a static elimination start time (for example, 12:45) ), The switch 73 of the ionizer 60 is turned on, and the switch 73 of the ionizer 60 is turned off at the scheduled time for completion of static elimination (for example, 12:55). At this time, the time during which the ionizer 60 is operated may be set to an upper limit (for example, 10 minutes) because the corrosion and environmental standards cannot be met when the ozone concentration increases.

  As described above, according to the electronic balance 101 of the present invention, static electricity inside the windshield 20 can be reduced. At this time, the DUT S may be placed inside the windshield 20. Thereby, since the inside of the windshield 20 and the measurement object S can be neutralized at a break time or the like, the weighing operation can be started smoothly after the break time ends (for example, at 13:00).

<Other embodiments>
(1) In the electronic balance 101 described above, one set of scheduled static elimination start time signal and scheduled static elimination end time signal are input. However, a plurality of scheduled static elimination start time signals and scheduled static elimination end time signals are included. It is good also as a structure which is input.
(2) The above-mentioned ion generation electrode is a DC system in which positive ions and negative ions are generated in separate discharge electrodes (equipped with an even number of discharge needles, each needle emitting only + ions and − ions), positive ions and Either an AC system that generates negative ions from the same electrode (releases + and − ions from one needle) may be used.
(3) In the electronic balance 101 described above, the ionizer 60 is configured to include a fan, but may be configured not to include a fan.

  The electronic balance of the present invention is used, for example, to reduce static electricity inside the windshield.

20 Windshield 21 Upper Wall (Upper Opening Opening / Closing Member)
22 Right side opening / closing member 23 Left side opening / closing member 30 Side wall 40 Weighing pan 41 Input unit 42 Display unit 45 Clock 60 Ionizer (static eliminator)
80 Weighing Mechanism 101 Electronic Balance 110 Electronic Balance Body 150 Control Unit

Claims (6)

An electronic balance body having a weighing pan, a weighing mechanism, a control unit, an input unit, and a display unit;
With windshield,
An electronic balance in which a weighing pan is arranged inside the windshield by arranging the windshield on the electronic balance body from above,
A static eliminator,
With a clock that measures time,
The static eliminator attached to the inside of the windshield can be controlled by the control unit,
When the scheduled static elimination start time and the scheduled static elimination end time are input at the input unit, the control unit operates the static eliminator at the scheduled static elimination start time, and operates the static eliminator at the scheduled static elimination end time. An electronic balance characterized by being terminated. The windshield has an upper wall and a side wall provided downward from a peripheral edge of the upper wall, and an opening and closing member capable of opening and closing the opening and the opening on the upper wall or the side wall. The electronic balance according to claim 1, wherein the electronic balance is formed. The electronic balance according to claim 1, wherein the static eliminator is removable from the inside of the windshield. The static eliminator includes a voltage generator,
The electronic balance according to any one of claims 1 to 3, further comprising an ion generating electrode that generates ions when a voltage is applied by the voltage generator. The electronic balance according to claim 4, wherein the ion generating electrode generates positive ions and negative ions. An electronic balance body having a weighing pan, a weighing mechanism, a control unit, an input unit, and a display unit;
Windshield,
A static eliminator,
With a clock that measures time,
By arranging the windshield on the electronic balance body from above, a weighing pan is arranged inside the windshield,
The static eliminator mounted inside the windshield is a method of using an electronic balance that can be controlled by the control unit,
Placing the object to be measured inside the windshield;
A step of inputting a scheduled static elimination start time and a scheduled static elimination end time at the input unit;
The control unit includes a step of operating the static eliminator at the static elimination start scheduled time, and ending the operation of the static eliminator at the static elimination end scheduled time.

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