JPH08184544A - Balance - Google Patents

Abstract

PURPOSE: To obtain a balance in which a supporting rod can be swung by a required amount with a small driving force. CONSTITUTION: A supporting rod 1 can swing freely about a fulcrum 2 and is driven through a drive plunger 8 comprising an electromagnetic coil 6 and a magnet 7. In the balance having such structure, the electromagnetic coil 6 is disposed while being spaced apart from the supporting rod 1. Since the supporting rod 1 is subjected to a driving force at a part spaced apart from the fulcrum 2, i.e., the driving force acts at a point spaced apart from the fulcrum 2, a larger driving torque can be obtained with the same driving force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balance device, such as a thermobalance device, having a structure in which a support rod swingable about a fulcrum is driven by a drive plunger.

[0002]

2. Description of the Related Art In a thermobalance apparatus, a sample container is provided at the tip of a supporting rod, and a sample inserted in this sample container is heated (cooled) in a heating furnace, and the weight change of the sample at that time is supported by the supporting rod. This is a thermal analysis device for detecting by swinging of. FIG. 5: is a block diagram which shows the conventional thermobalance apparatus. The thermobalance apparatus shown in the figure has a structure in which a single beam (supporting rod) 101 is swingably supported by a fulcrum 102, and a sample container 104 is held at the tip via a sample holder 103. ing.

The beam 101 is always adjusted so as to maintain a horizontal position, and in this state, the sample in the sample container is heated by the heating furnace 105. Then, the weight of the sample changes in accordance with the change in the physical properties of the sample due to heating, and the beam 10
1 swings around the fulcrum. Therefore, the swing (displacement) of the beam 101 is detected by the displacement sensor 106, and a drive current is output from the position control circuit 107 to the electromagnetic coil 109 of the drive plunger 108 based on the detected value, and the beam 101 is moved horizontally. Return to position.

At this time, the current value of the electromagnetic coil 109 required at this time is input to the measuring circuit 110 and converted into a change in the load weight acting on the beam 101 (that is, a change in the weight of the sample) to measure the thermogravimetric value of the sample. (TG) is realized. In addition, returning the beam 101 to the original horizontal position is
This is because the sample container 104 is always arranged at the center position in the heating furnace 105 to form a uniform heating state.

In the conventional thermobalance device, the drive plunger 108 for driving the beam 101 is provided at the fulcrum 102 of the beam 101. The fulcrum 102 part of this beam 101 is shown in FIG. A coil frame 112 is provided at a fulcrum 102 portion of the beam 101 so as to surround the magnet 111, and an electromagnetic coil 109 is wound around the coil frame 112. Beam 101 is coil frame 1
It is supported on the fulcrum 102 by a wire or the like joined to 12. Then, when a driving current is passed through the electromagnetic coil 109, a driving force is generated by the electromagnetic action, and the beam 101 swings around the fulcrum 102.

[0006]

As is well known, the driving torque has a value obtained by multiplying the driving force by the distance from the fulcrum. Therefore, in the conventional thermal balance apparatus in which the driving force generated by the driving plunger 108 is applied to the fulcrum 102 of the beam 101, a large driving current is required to obtain the driving torque required for swinging the beam 101. The present invention has been made to solve the problems of the prior art, and an object thereof is to provide a balance device that can swing the supporting rod by a required amount with a small driving force.

[0007]

In order to achieve the above-mentioned object, a balance device of the present invention is provided with a structure in which a support rod swingable about a fulcrum is driven by a drive plunger, and the drive plunger is provided. It is characterized in that the point of action of the driving force due to is provided at a portion separated from the fulcrum of the support rod.

More specifically, the supporting rod is swingable around a fulcrum, and the supporting rod is driven by a drive plunger including an electromagnetic coil and a magnet, and the electromagnetic coil is supported by the supporting rod. It is characterized in that it is arranged at a site separated from the fulcrum of.

[0009]

According to the above-mentioned structure, since the supporting rod receives the driving force at the portion separated from the fulcrum, the action point of the driving force is separated from the fulcrum, so that a large driving torque can be obtained with the same driving force. .

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 is a perspective view showing a balance device according to an embodiment of the present invention, and FIG. 2 is a front view thereof. The support rod 1 is supported by a wire 3 joined to a fulcrum 2. The wire 3 is fixed to a device body (not shown) without slack, and the support rod 1 is swingable around the wire 3. A sample container 4 is provided at the tip of the support rod 2. A cylindrical coil frame 5 is attached to the base end of the support rod 2, and an electromagnetic coil 6 is wound around the coil frame 5. Here, the center of the coil frame 5 is separated from the fulcrum 2 by an arbitrary distance L.

The magnet 7 is arranged so as to penetrate through the hollow portion of the coil frame 5, and its outer shape is such that when the coil frame 5 swings around the fulcrum 2, the front and rear end edges 5a and 5b of the hollow portion are formed. It has a fan shape along the drawn trajectory. The magnet 7 and the electromagnetic coil 6 (including the coil frame 5) constitute a drive plunger 8 for swinging the support rod 1.

In the balance device having the above-described structure, since the driving plunger is not provided at the fulcrum 2, the supporting rod 1 can be supported by a simple supporting structure. Moreover, unlike the conventional example shown in FIG. 6 in which a wire is joined to the coil frame 112 to support the beam (supporting rod) 101, a tensile force from the wire 3 may act on the coil frame 5. Since there is no coil frame 5, there is no risk of deformation.

When a driving current is passed through the electromagnetic coil 6, a driving force is generated in the coil frame 5 by the electromagnetic action. Support rod 1
Oscillates around the fulcrum 2 by a driving torque of a value obtained by multiplying this driving force by the distance L from the point of application of the driving force to the fulcrum 2. If the driving force is the same, the driving torque is
The longer the distance L from the point of action of the driving force to the fulcrum 2, the larger the distance. Therefore, it is preferable that the distance L be as long as possible in consideration of the structure of the balance device and the strength of the support rod 1. Further, in the above configuration, the drive plunger 8 is installed at the base end portion of the support rod 1, but the drive plunger 8 may be provided at any portion such as the middle portion or the tip end portion side of the support rod 1 except the fulcrum 2 portion. Can be installed.

Next, an embodiment in which the present invention is applied to a thermobalance device will be described with reference to FIGS. 3 and 4. FIG. 3 is a configuration diagram showing the overall configuration of the thermobalance device according to this embodiment. This thermobalance device includes a first support rod 11, a second support rod 11,
It has twelve. The support rods 11 and 12 are swingable around fulcrums 13 and 14, respectively. Connection connectors 15 and 15 are provided at the tips of the support rods 11 and 12, and the sample holder 1 is attached to the connection connectors 15 and 15.
6 and 17 can be detachably attached.

Further, an electromagnetic coil 18 wound around a coil frame is provided at a portion separated from the fulcrum 13 of the first support rod 11 by an arbitrary distance. This electromagnetic coil 18 is a magnet 1
It is arranged around 9. The electromagnetic coil 18 and the magnet 19 wound around the coil frame constitute a drive plunger that applies a drive torque to the first support rod 11 and forcibly swings the first support rod 11 by a necessary angle.

Further, sub electromagnetic coils 20 and 21 wound around a coil frame are provided at portions apart from the fulcrums 13 and 14 of the first and second support rods 11 and 12 by an arbitrary distance. These sub electromagnetic coils 20 and 21 are also arranged around the magnets 22 and 23, respectively. Sub electromagnetic coil 2
0 and 21 and magnets 22 and 23 are also provided on the support rods 1 respectively.
A drive plunger is configured to apply a torque to 1 and 12 to forcibly swing it by a required angle.

As described above, the first supporting rod 11 is provided with the electromagnetic coil 18 and the sub electromagnetic coil 20, of which the electromagnetic coil 18 is the first based on the weight change of the sample.
With respect to the swing of the support rod 11, the support rod 11 has a function of swinging in the opposite direction to maintain a horizontal posture. On the other hand, the sub-magnetic coil 20 prevents the supporting rod 11 from swinging due to environmental factors such as convection in the heating furnace 24.
Has a function of swinging in the opposite direction to maintain a horizontal posture. Details of each of these functions will be described later.

As shown in FIG. 4, the electromagnetic coil 18 and the auxiliary electromagnetic coil 20 are respectively wound around a single coil frame 25 and installed at the same position on the first support rod 11, so that the structure is simplified. preferable. In this case, the magnets 19 and 22 can also be shared by a single magnet. The structures of the electromagnetic coil 18, the sub electromagnetic coil 20, and the magnet wound around the coil frame 25 may be the same as those of the balance device shown in FIGS. Here, since the electromagnetic coil 18 and the sub-electromagnetic coils 21 and 20 (that is, the drive plungers) are installed at the positions separated from the fulcrums 13 and 14, a small drive is required as compared with the case where they are installed at the fulcrums 13 and 14. A large torque can be obtained with the electric current.

Movable weights 26 and 27 are attached to the first and second support rods 11 and 12, respectively. When carrying out the thermal analysis, the positions of the movable weights 26, 27 are adjusted to adjust the support rods 11, 12 in a horizontal posture. Also,
Shutters 28 and 29 having slits 28a and 29a are provided at the rear ends of the first and second support rods 11 and 12, respectively. The light sources 30 and 31 are installed at arbitrary positions facing the shutters 28 and 29, and the first light sources 30 and 31 are provided at arbitrary positions that can receive the light of the light sources 30 and 31 transmitted through the slits 28a and 29a. , Second light receiving sensors 32, 33 are installed. These shutters 2
8, 29, light sources 30, 31, first and second light receiving sensors 3
Reference numerals 2 and 33 constitute displacement detecting means for detecting the displacement due to the swing of the support rods 11 and 12.

The displacement detection signal of the second support rod 12 by the second light receiving sensor 33 is sent to the control circuit 34 of the auxiliary electromagnetic coils 20 and 21. The control circuit 34 is composed of a PID circuit, calculates the displacement amount of the second support rod 12, and swings the first and second support rods 11 and 12 in the opposite direction (pullback direction) by this displacement amount. The drive circuit 3 sends a control signal to the effect that
Output to 5, 36. When the thermobalance device is used as a differential type, the first support rod 11 is the sample side and the second support rod 12 is the reference side. Therefore,
The calculated displacement amount of the second support rod 12 is caused by an environmental factor in the heating furnace.

The drive circuits 35 and 36 include gain setters 35a and 36a and power amplifier circuits 35b and 36b, respectively.
The drive current is output based on the control signal to swing the auxiliary electromagnetic coils 20 and 21 in the pullback direction.
When the drive current is input, the sub electromagnetic coils 20 and 21 generate a drive torque by an electromagnetic action, and pull back the first and second support rods 11 and 12 by a displacement amount caused by an environmental factor in the heating furnace 24. Rock in the direction. As a result, the second support rod 12 is pulled back to the horizontal position, but the first support rod 11 swings due to the change in the weight of the sample.
Still tilting.

On the other hand, the displacement detection signal of the first support rod 11 by the first light receiving sensor 32 is sent to the control circuit 37 of the electromagnetic coil 18. The control circuit 37 is composed of a PID circuit and a power amplifier circuit, calculates the amount of displacement of the first support rod 11, and swings the first support rod 11 in the opposite direction (pullback direction) by this displacement amount. A control current for causing the electromagnetic coil 18 to be output. Here, the first light receiving sensor 3
2 detects the displacement of the first support rod 11 in a state where the displacement caused by environmental factors in the heating furnace 24 is removed by the sub electromagnetic coil 20.

When a drive current is input, the electromagnetic coil 18 generates a drive torque by an electromagnetic action, and swings the first support rod 11 in the pullback direction by the displacement amount caused by the weight change of the sample. In this way, the first support rod 1
1 is also returned to the horizontal position. The current value required for the electromagnetic coil 18 to pull back the first support rod 11 in the horizontal direction is detected by the current detection circuit 38 and output to the TG measurement circuit 39. The current detection circuit 38 and the TG measurement circuit 39 constitute TG detection means for detecting the thermogravimetric weight of the sample, and in order to return the displacement amount of the first support rod 1 caused by the weight change of the sample to the horizontal posture. It is detected by the current value required for the above, and the weight change of the sample is calculated from this current value as a function of temperature (or time).

As described above, the thermobalance device of this embodiment is capable of performing thermogravimetric measurement (TG) in the form of a differential type, but further, the first or second support rod 11, It is also possible to perform thermogravimetric measurement (TG) using a single beam type configuration using either one of the twelve. That is, when the first support rod 11 is used, the displacement due to the swing of the support rod 11 is detected by the first light receiving sensor 32, and the control circuit 37 detects the displacement detection signal from the first support rod 11. The displacement amount is calculated, and the drive current necessary for returning the support rod 11 to the horizontal posture is output. This drive current activates the electromagnetic coil 18 and pulls back the first support rod 11 to the horizontal posture by the electromagnetic action.
The value of the drive current required at this time is detected by the current detection circuit 38, and the weight change of the sample is calculated by the TG measurement circuit 39 as a function of temperature (or time).

When the second supporting rod 12 is used, the displacement due to the swing of the supporting rod 12 is detected by the second light receiving sensor 33, and the control circuit 34 uses the second displacement detection signal to detect the second displacement. The displacement amount of the support rod 12 is calculated and a control signal is output to the drive circuit 36. The drive circuit 36 outputs a drive current required to return the support rod 12 to the horizontal posture.
The sub-electromagnetic coil 21 is actuated by this drive current, and the second support rod 12 is returned to the horizontal posture by the electromagnetic action.

The value of the drive current required at this time is detected by the current detection circuit 38, and the TG measurement circuit 39 calculates the weight change of the sample as a function of temperature (or time). For this reason, the thermobalance device of this embodiment is provided with a switching means 40 so that the auxiliary electromagnetic coil 21 can be connected to the current detection circuit 38. The switching means 40 is
As shown in FIG. 1, in addition to the mechanical switch provided between the sub electromagnetic coil 21 and the current detection circuit 38, a signal from the electromagnetic coil 18 or the sub electromagnetic coil is included in the processing program of the current detection circuit 38. It is also possible to adopt a configuration in which the signal from 21 is selected and processed.

When thermogravimetric measurement (TG) is carried out using the above-mentioned thermobalance device, the differential type is higher because the influence of convection in the heating furnace 24 is offset. Measurement accuracy can be obtained. On the other hand, differential thermal analysis (DT
When performing A) or differential scanning calorimetry (DSC),
Since the single beam type configuration in which the sample and the reference substance are held on the single support rod allows more uniform heating in the heating furnace 24, higher measurement accuracy can be obtained.

Therefore, when performing thermal analysis centering on thermogravimetric measurement (TG), the first and second support rods 1
It is preferable to attach a sample holder holding a single sample container to 1 and 12 for measurement. When performing thermal analysis centering on differential thermal analysis (DTA) or differential scanning calorimetry (DSC), the first or second support rod 1
It is preferable to attach a sample holder holding a pair of sample containers to either one of 1 and 12 for measurement. Incidentally, it is of course possible to carry out the thermal analysis with other combinations if necessary. In this way, the thermal analysis apparatus of this embodiment can easily form either a differential type or a single beam type according to the type of thermal analysis.

The present invention is not limited to the above embodiment. For example, the present invention can be applied not only to the thermobalance device but also to various balance devices including a configuration in which the support rod is driven by the electromagnetic plunger.

[0030]

As described above, according to the balance device of the present invention, since the supporting rod receives the driving force at the portion separated from the fulcrum, the action point of the driving force is separated from the fulcrum.
A large driving torque can be obtained with the same driving force, and as a result, the supporting rod can be swung by a required amount with a small driving force.

[Brief description of drawings]

FIG. 1 is a perspective view of a balance device according to an embodiment of the present invention.

FIG. 2 is a front view of the same.

FIG. 3 is a configuration diagram showing an embodiment in which the present invention is applied to a thermobalance device.

FIG. 4 is a perspective view showing a configuration of an electromagnetic coil used in the embodiment.

FIG. 5 is a configuration diagram of a conventional thermobalance device.

FIG. 6 is a front view showing a fulcrum portion of a support rod in the conventional apparatus.

[Explanation of symbols] 1: Support rod 2: Support point 3: Wire 5: Coil frame 6: Electromagnetic coil 7: Magnet 8: Drive plunger

Claims (2)

[Claims] 1. A support rod swingable about a fulcrum,
A balance device having a structure driven by a drive plunger, wherein a point of action of a driving force by the drive plunger is provided at a portion separated from a fulcrum of the support rod. 2. A balance apparatus having a structure in which a support rod is swingable about a fulcrum and a drive plunger including an electromagnetic coil and a magnet drives the support rod, wherein the electromagnetic coil is supported by the support rod. A balance device characterized in that the balance device is arranged at a position apart from the fulcrum of the rod.