JP2005331432A - Thermal analyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal analyzer capable of preventing measuring sensitivity from getting worse by heat radiation from a sample, and having high strength for supporting a sample mounting part such as a thermosensitive sheet. <P>SOLUTION: This thermal analyzer has the thermosensitive sheet 21 for mounting the sample, a balance beam 19 for supporting the thermosensitive sheet 21, and a thermocouple 15 with a temperature measuring part fixed to the thermosensitive sheet 21. In the thermal analyzer, the thermosensitive sheet 21 is supported with the balance beam 19 by a wire 16 having one end fixed to the thermosensitive sheet 21 and having the other end engaged with the balance beam 19, and a space T is provided between the thermosensitive sheet 21 and the balance beam 19. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thermal analyzer that measures the thermal characteristics of a sample in a state where the sample is placed on a heat sensitive plate provided on a support rod.

  Thermal analysis apparatuses include a TG (Thermogravimetry) apparatus, a DTA (Differential Thermal Analysis) apparatus, a DSC (Differential Scanning Calorimeter) apparatus, and various other types. A TG device is a device that measures a change in weight of a compound as a sample with respect to a change in temperature or the passage of time. A DTA device measures the temperature difference that occurs between a sample and a thermally stable standard substance at the same time when the sample reacts to heat, and measures the heat change generated in the sample from the temperature difference. A device to know. A DSC apparatus is an apparatus that measures the amount of heat absorbed or dissipated by a sample under heating, cooling, or constant temperature.

  Some of these thermal analyzers perform measurement with a sample placed on a heat sensitive plate provided on a support rod. For example, a TG device is known as a thermal analysis device that uses a balance beam as a support rod and measures the thermal characteristics of a sample based on rotational shake of the balance beam (see, for example, Patent Document 1). ).

JP-A-5-052732 (pages 2 and 3, FIG. 1)

  By the way, in the thermal analysis apparatus using the support rod disclosed in Patent Document 1, the thermocouple 115 penetrates through the support rod 119 as shown in FIG. The tip of the thermocouple 115, that is, the temperature measuring unit, was fixed to the bottom surface of the heat sensitive plate 121 by spot welding. Thereby, the temperature of the heat sensitive plate 121 was detected by the thermocouple 115. Moreover, the thermocouple 115 also fulfilled the function of placing the heat sensitive plate 121 at a predetermined measurement position Y by itself. That is, the support bar 119 supported the heat sensitive plate 121 at the measurement position Y via the thermocouple 115. A sample container 104 containing a sample to be measured is placed on a heat sensitive plate 121.

  Further, as another structure for supporting the heat sensitive plate 121, as shown in FIG. 7B, a pipe 117 is welded to the heat sensitive plate 121, and a support bar 119 is inserted into the pipe 117 so that the heat sensitive plate 121 is attached. Some supported it.

  As shown in FIG. 7A, in the structure in which the heat sensitive plate 121 is supported only by the thermocouple 115, the strength of supporting the heat sensitive plate 121 is insufficient because the strength of the thermocouple 115 is low. Therefore, when the sample container 104 is attached to or detached from the heat sensitive plate 121, the position of the heat sensitive plate 121 may move or the heat sensitive plate 121 may be inclined. Further, as shown in FIG. 7B, the structure for supporting the thermal plate 121 using the pipe 117 has sufficient strength to support the thermal plate 121, but the sample container placed on the thermal plate 121. When the sample inside 104 caused a thermal change, heat escaped from the heat sensitive plate 121 through the pipe 117 and the support bar 119. As a result, the sensitivity of the measurement may be reduced.

  The present invention has been made in view of the above-described problems, and prevents a decrease in measurement sensitivity due to the escape of the heat of the sample, and a strong heat that supports the sample mounting portion such as a heat sensitive plate. An object is to provide an analyzer.

  In order to achieve the above object, a thermal analysis apparatus according to the present invention includes a thermosensitive plate on which a sample is placed, a thermocouple to which a temperature measuring unit is fixed to the thermosensitive plate, a support rod that supports the thermocouple, and one end. Has a wire fixed to the heat sensitive plate and the other end engaged with the support rod, and a space is provided between the heat sensitive plate and the support rod.

  The term “fixed” as used herein refers to a state in which the wire and the heat sensitive plate are joined by welding, an adhesive, or the like so as not to move relative to each other. The term “engagement” as used herein means that the wire and the support rod function so that the support rod functions to prevent the wire from changing its position when the wire is about to move relative to the support rod. Is the relationship. For example, a state where the wire is fixed in a fixed position with respect to the support rod, a state where the wire is fixed to the outer peripheral surface of a pipe which is loosely or relatively tightly fitted to the support rod, and the like are considered as the above-mentioned engagement.

  The thermocouple is formed by joining conductive wires made of different materials at two points. In this thermocouple, an electromotive force is generated when two joined points are maintained in different temperature atmospheres. The magnitude of this electromotive force depends on the type of material forming the conductive wire and the temperature difference at the junction of the conductive wire. Therefore, if the electromotive force is detected with the temperature at one junction point kept constant, the temperature at the other junction point can be measured. In the present invention, the temperature measuring portion of the thermocouple is one of the two junction points. If this temperature measuring unit is fixed to the heat sensitive plate, the temperature change of the sample placed on the heat sensitive plate can be measured. The thermocouple also has a role of supporting the heat sensitive plate on the support rod by fixing the temperature measuring part to the heat sensitive plate.

  In the thermal analysis apparatus having the above-described configuration, a heat sensitive plate is supported by a support rod using a wire in addition to a thermocouple. This increases the strength of supporting the heat sensitive plate compared to a structure that supports the heat sensitive plate using only a thermocouple, so the position of the heat sensitive plate moves or the heat sensitive plate tilts when attaching or detaching the sample. Disappears. Further, since the wire joining the heat sensitive plate and the support rod is a long member having a small wire diameter, the heat capacity is small. Therefore, the amount of heat escaping from the heat sensitive plate to the support rod through the wire can be reduced. Thereby, it can prevent that the sensitivity of a measurement falls.

  In the thermal analysis apparatus according to the present invention, it is desirable that a pipe is provided at an end of the support bar, and the wire is engaged with the support bar via the pipe. In this case, the length of the pipe along the axial direction of the support rod is preferably 3 mm or less. If it carries out like this, the contact area of a wire and a support bar can be made small. As a result, the amount of heat escaping from the heat sensitive plate to the support rod through the wire can be reduced, so that the measurement sensitivity can be prevented from being lowered.

  In the thermal analysis apparatus according to the present invention, it is desirable that the thermal plate is provided with a plurality of projecting pieces arranged so as to protrude outward and have portions corresponding to the axis of the support rod as spacing portions. . In this case, it is preferable that the wires are provided on both sides of the axis of the support rod, and each wire is fixed to one of the plurality of projecting pieces. If a protrusion is provided on the heat sensitive plate, it is possible to prevent the sample placed on the heat sensitive plate from falling off the heat sensitive plate.

  In addition, if a plurality of projecting pieces are provided so that the portion corresponding to the axis of the support rod is an interval portion, the sample can be gripped without touching the projecting piece at the interval portion. It can be easily attached and detached. Furthermore, if the wires are provided on both sides of the axis of the support rod and each wire is fixed to one projecting piece, the heat sensitive plate is supported by the wires at positions that are substantially symmetrical on both sides of the plate. Is done. As a result, the heat sensitive plate can be supported more stably.

  In the thermal analyzer according to the present invention, it is desirable that four protrusions are provided on the heat sensitive plate, and the wire is fixed to the two protrusions on the near side as viewed from the support rod. If there are four projecting pieces, a spacing portion can be reliably provided on a portion corresponding to the axis of the support bar on the heat sensitive plate. In this way, the sample can be easily attached and detached. Further, if the wire is fixed to the two front projecting pieces, the shape of the wire and the structure of the portion that supports the heat sensitive plate can be simplified.

  In the thermal analysis apparatus according to the present invention, the wire is preferably made of the same material as the thermocouple. In this way, it is not necessary to form a wire using a new material, so that the material can be saved.

  In the thermal analysis apparatus according to the present invention, it is desirable that the wire has the same cross-sectional shape as the thermocouple. By doing so, the conductive wire constituting the thermocouple can be used as a wire, so that material can be saved.

  In the thermal analysis apparatus according to the present invention, the wire is preferably formed of a platinum rhodium (PtRh) alloy having a rhodium (Rh) content of 5 to 40%. If the rhodium content in the platinum rhodium alloy is less than 5%, the platinum rhodium alloy becomes too soft. If a wire is formed using such a platinum rhodium alloy, the wire becomes too soft, and the strength for supporting the heat sensitive plate may be lowered. On the other hand, if the rhodium content is higher than 40%, the platinum rhodium alloy becomes too hard. If a wire is formed using such a platinum rhodium alloy, the wire becomes too hard and it becomes difficult to process the wire. If the rhodium content is 5 to 40%, the wire can be easily processed and the strength for supporting the heat-sensitive plate can be increased.

  In addition, platinum rhodium alloy is one of high heat resistant materials that are difficult to oxidize. Therefore, it is possible to prevent the wire from being oxidized by the heat transmitted from the heat sensitive plate. Note that the wire may be formed of a heat resistant material that is difficult to oxidize other than a platinum rhodium alloy.

  According to the thermal analyzer of the present invention, the heat sensitive plate is supported by the support rod using a wire in addition to the thermocouple. As a result, the strength of supporting the heat sensitive plate can be increased compared to a structure that supports the heat sensitive plate using only a thermocouple, so that the position of the heat sensitive plate moves when the sample is attached to or detached from the heat sensitive plate. Will not tilt. In addition, since the wire joining the heat sensitive plate and the support rod has a small heat capacity, the amount of heat escaping from the heat sensitive plate to the support rod through the wire can be reduced. Thereby, it can prevent that the sensitivity of a measurement falls.

  Hereinafter, the case where the thermal analysis apparatus according to the present invention is applied to a TG apparatus will be described as an example. Of course, the present invention is not limited to this embodiment.

  FIG. 2 shows a TG device which is an embodiment of a thermal analysis device according to the present invention. FIG. 3 specifically shows a portion related to the balance device in the thermal analyzer shown in FIG. FIG. 1 is an enlarged view of the sample placement portion indicated by the arrow P in FIG. FIG. 1A is a diagram of the sample mounting unit viewed from the side according to the arrow Q in FIG. 2, and FIG. 1B is a diagram of the sample mounting unit viewed in plan according to the arrow S in FIG. is there.

  A TG device 1 shown in FIG. 2 includes a sample changer 2 that automatically performs sample replacement and a balance device 3 that performs TG measurement. The sample changer 2 includes a turntable 6 where a plurality of sample containers 4 are placed, and a transport arm 7 that transports the sample containers 4. An appropriate amount of the sample to be measured is accommodated in the sample container 4. A table rotating device 8 is attached to the turntable 6. The table rotating device 8 is a device for rotating the turntable 6 intermittently about the central axis X0. This intermittent rotation is an operation for sequentially transporting different sample containers 4 to the removal position P0.

  The table rotating device 8 can be configured by any conventionally known rotary driving device. For example, a structure in which the rotation of a rotating device such as a motor is transmitted to the turntable 6 by a power transmission element such as a gear can be employed. In this case, in order to realize intermittent rotation of the turntable 6, it is desirable to use a stepping motor or a servo motor as a motor that is a power source. In order to measure the rotation angle of the turntable 6, it is desirable to attach a pulse generator to the rotation axis of the turntable 6 or to arrange a photo sensor around the rotation axis of the turntable 6. .

  The transfer arm 7 is supported by a support shaft 9. An arm rotating device 11 and an arm elevating device 12 are attached to the support shaft 9. The arm rotating device 11 is a device for rotating the transport arm 7 as shown by an arrow A around the support shaft 9. The arm rotation device 11 can be configured by any conventionally known rotary drive device. For example, a structure in which the rotation of a rotation device such as a motor is transmitted to the support shaft 9 by a power transmission element such as a gear can be employed. In this case, in order to control the rotation angle of the transfer arm 7 to a desired value, it is desirable to use a stepping motor or a servo motor as a motor that is a power source. Further, in order to detect the rotation angle of the transfer arm 7, it is desirable to attach a pulse generator to the support shaft 9 or arrange a photosensor around the support shaft 9.

  Next, the arm lifting device 12 is a device for moving the transport arm 7 up and down as indicated by an arrow B. The arm elevating device 12 can be configured by any conventionally known reciprocating linear drive device, but can be configured by using a power transmission element that converts rotation of a rotating device such as a motor into linear motion. As elements for converting the rotational motion into linear motion in this manner, for example, a screw shaft fixed to a rotation source such as a motor, and a slide member fixed to the support shaft 9 and screwed to the screw shaft. Can be configured. According to this configuration, when the rotation source rotates, the screw shaft fixed to the rotation source rotates, and at that time, the slide member that is screw-fitted to the screw shaft slides in the axial direction of the screw shaft. The support shaft 9 on which is fixed moves linearly and moves up and down. A power conversion element composed of a worm and a worm wheel can also be used.

  Next, a pair of fingers 13 and 13 for gripping the sample container 4 from both the left and right sides thereof are provided at the front end portion of the transfer arm 7 so as to be reciprocally movable in parallel as indicated by an arrow C, that is, to be able to open and close. ing. In addition, an opening / closing driving device 14 for opening and closing the fingers 13 and 13 as indicated by an arrow C is provided inside the transfer arm 7. The opening / closing drive device 14 can be constituted by any conventionally known opening / closing drive mechanism.

Next, the balance apparatus 3 includes a balance beam 19 rotatably supported by a torsion band 18 constituting a fulcrum, and an electric furnace 24 for changing the temperature of the sample. In the present embodiment, it is assumed that measurement is performed without using a standard substance, and therefore, only one balance beam 19 is used for placing a sample as a measurement target. If a measurement using a standard substance is performed, a total of two balance beams 19 are used, one for the sample to be measured and one for the standard substance. As shown in FIG. 3, the balance beam 19 is formed by connecting a sample side beam 19 a and a detection side beam 19 b using a socket 20. The balance beam 19 is made of alumina (Al ₂ O ₃ ), for example.

  As shown in FIGS. 1A and 1B, the balance beam 19 has a heat sensitive plate 21 at the tip thereof. That is, the balance beam 19 serves as a support rod for supporting the heat sensitive plate 21. A sample container 4 containing a sample to be measured is placed on the heat sensitive plate 21 and used for measurement. Further, a thermocouple 15 is disposed inside the balance beam 19. Specifically, a through hole Z having a diameter slightly larger than that of the thermocouple 15 is provided in the balance beam 19, and the thermocouple 15 is inserted into the through hole Z.

  In this embodiment, a thermocouple 15 formed by joining a platinum (Pt) wire and a platinum rhodium alloy wire is used. In this thermocouple 15, the junction between the platinum wire and the platinum rhodium wire constitutes a temperature measuring unit. By fixing the temperature measuring part of the thermocouple 15 to the bottom surface of the heat sensitive plate 21 by welding, for example, the temperature change relating to the sample placed on the heat sensitive plate 21 can be measured.

  The heat sensitive plate 21 is formed of a platinum rhodium alloy in the same manner as one of the conductive wires constituting the thermocouple 15. Further, a plurality of, for example, four projecting pieces 25 are provided on the heat sensitive plate 21. As shown in FIG. 1A, these protrusions 25 are provided on the outer periphery of the heat sensitive plate 21 so as to protrude in the upper surface direction of the heat sensitive plate 21. Further, as shown in FIG. 1B, the projecting piece 25 is provided such that a portion corresponding to the axis X1 of the balance beam 19 is a spacing portion D0.

  The pipe 17 is fitted to the end of the balance beam 19 on the side where the heat sensitive plate 21 is provided. The pipe 17 has a length L0 along the axial direction of the balance beam 19 of 3 mm or less. The wall thickness L1 of the pipe 17 is 0.1 mm to 0.3 mm. Then, one end of the wire 16 is fixed by welding, for example, on both sides of the axis 17 of the balance beam 19 of the pipe 17. In addition, the other end of the wire 16 is connected to two protrusions 25a positioned on the near side as viewed from the balance beam 19, that is, on the right side of the heat sensitive plate 21 in FIGS. It is fixed.

  The wire 16 is formed of a platinum rhodium alloy in the same manner as the thermocouple 15, and the cross-sectional shape thereof is the same as the conductive wire used as the thermocouple 15. That is, the conductive wire of the thermocouple 15 can be used as the wire 16. For example, a platinum rhodium wire having a circular cross section with a diameter of 0.3 mm to 0.5 mm is used as one conductive wire of the thermocouple 15, and the wire 16 can be formed of a platinum rhodium wire having the same cross sectional shape.

  As described above, in the present embodiment, the thermocouple 15 is fixed to the bottom surface of the heat sensitive plate 21 and one end of the wire 16 is engaged with the balance beam 19 via the pipe 17 fitted to the balance beam 19. The other end of the wire 16 is fixed to the protruding piece 25a of the heat sensitive plate 21. In this way, the heat sensitive plate 21 is supported by the balance beam 19. At this time, the heat sensitive plate 21 is supported so as not to contact other than the thermocouple 15 and the wire 16, that is, to provide a space T between the heat sensitive plate 21 and the balance beam 19.

  Returning to FIG. 2, an electromagnetic compensator 22 is provided in the vicinity of the fulcrum 18 of the balance beam 19. In addition, a shake detection device 23 is provided at the rear end of the balance beam 19. The electric furnace 24 incorporates a heater that generates heat when energized, and has a space R having a volume that can accommodate the heat sensitive plate 21. In addition, a furnace moving device 26 is attached to the electric furnace 24. The furnace moving device 26 is a device that translates the electric furnace 24 between a position that covers the heat sensitive plate 21 and a position that opens the heat sensitive plate 21 to the outside. FIG. 2 shows a state where the electric furnace 24 is placed at a position where the heat sensitive plate 21 is opened to the outside.

  The furnace moving device 26 can be configured by any conventionally known parallel moving device. For example, the electric furnace 24 is supported by a guide element such as a rail so as to be linearly movable, and the electric furnace 24 is linearly driven by a linear drive device. It is possible to adopt a configuration such as reciprocating. In this case, the linear drive device is, for example, a linear drive device in which a slider is screwed to a screw shaft and the slider is linearly moved by rotating the screw shaft, or a linear drive device using a wire that moves around. Etc. are considered.

  For example, as shown in FIG. 3, the electromagnetic compensator 22 includes a permanent magnet 27 fixed to a balance beam 19 near the fulcrum 18, a coil 28 disposed in the magnetic field region of the permanent magnet 27, and voltage detection. And a resistor 29 for use. One end of the resistor 29 is taken out to output a TG output signal, and the TG output signal is input to the TG arithmetic circuit 36. The TG calculation circuit 36 calculates a change in the weight of the sample with respect to a change in the temperature of the sample based on the TG signal from the electromagnetic compensator 22. The calculation result is displayed so that it can be visually recognized by the display device 37 as necessary. As the display device 37, for example, a video display device such as a CRT (cathode ray tube) display or a liquid crystal display, or a print display device such as a printer is used.

  2 includes, for example, a light shielding plate 31 fixed to the rear end of the balance beam 19, a light source 32 that emits light toward the light shielding plate 31, as shown in FIG. And a light receiving element 33 disposed on the opposite side of the light shielding plate 31 with respect to the light source 32. The output terminal of the light receiving element 33 is connected to a PID (proportional, integral, derivative) control circuit 34. The output terminal of the PID control circuit 34 is connected to the power amplifier 43.

As is well known, the PID control circuit 34 quickly performs the P action (Proportional action) that makes the deviation close to zero in feedback control, the I action (Integral action) that makes the deviation completely zero, and the deviation quickly. Control is performed in combination with a D action (Derivative action / differential action) that converges to. For example, as shown in FIG. 6, the PID control circuit 34 includes a proportional element 46, an integral element 47, and a differential element 48. When the deviation input is Ve and the PID output is Vo,
Vo = Kp {1+ (1 / Ti) ∫Vedt + Td · dVe / dt}
Where Kp is the proportional gain,
Ti is the integration time
Td controls the derivative time.

  In FIG. 3, a pair of stoppers 44 are provided at appropriate positions on the opposite side of the heat sensitive plate 21 with the fulcrum 18 interposed therebetween to prevent excessive rotation vibration of the balance beam 19, that is, excessive inclination vibration. The balance beam 19 can rotate around the fulcrum 18 within an angle range until it comes into contact with these stoppers 44.

  The sample change control circuit 39 shown in FIG. 4 performs control for realizing a process of exchanging and placing different sample containers 4 on the heat sensitive plate 21 at the tip of the balance beam 19 using the sample changer 2 shown in FIG. Do. The sample change control circuit 39 is configured as a single control circuit connected to a host computer that controls the overall control of the thermal analyzer, or a control circuit that forms part of the host computer. The sample change control circuit 39 can be configured using, for example, a sequence circuit that does not use a computer, a programmable controller that is a kind of computer, a general computer, or the like.

  The sample exchange signal S1 is input to the input port of the sample change control circuit 39 in a timely manner. This sample exchange signal S1 is a signal for instructing the sample change control circuit 39 that the timing for exchanging the sample has arrived. For example, the sample exchange signal S1 is sent from a host computer, or is sent from a host computer or other input device. Sent from the operator.

  2 is connected to the output port of the sample change control circuit 39. The table rotating device 8, the arm rotating device 11, the arm lifting device 12, the finger opening / closing device 14, and the furnace moving device 26 shown in FIG. The sample change control circuit 39 executes a desired sample exchange process by operating these devices according to a predetermined sequence.

  The operation of the TG device having the above configuration will be described below. Since this TG apparatus has a TG measurement function and a sample automatic exchange function, they will be described individually.

(TG measurement function)
When performing TG measurement, in FIG. 3, the balance beam 19 supported with the torsion band 18 as a fulcrum is in a state of being able to freely rotate and tilt in the direction of arrow DD ′ around the torsion band 18. . A sample container 4 is placed on the heat sensitive plate 21 at the tip of the balance beam 19, and a sample to be measured is accommodated in the sample container 4. When performing the TG measurement, the electric furnace 24 is placed at a measurement position indicated by a broken line, so that the sample container 4 is disposed in the electric furnace 24.

  A shielding plate 31 provided at the rear end of the balance beam 19 blocks an optical path from the light source 32 to the light receiving element 33. When the balance beam 19 is tilted from the horizontal position, that is, from the equilibrium position, the output signal of the light receiving element 33 changes from the reference signal. Therefore, the position of the balance beam 19 can be detected by detecting this signal change. The output signal of the light receiving element 33 is applied as a control signal to the coil 28 of the electromagnetic compensator 22 through the PID control circuit 34 and the power amplifier 43. The coil current i0 is converted into a voltage by the detection resistor 29, and the voltage is output as a TG output signal.

  The temperature of the electric furnace 24 changes according to a predetermined temperature control program, and the temperature of the sample in the sample container 4 changes accordingly. When the weight changes in the sample during the temperature change, the balance beam 19 swings in the D direction or the D ′ direction. This shake is detected by the light receiving element 33, and the PID control circuit 34 and the power amplifier 43 cause the coil 28 to pass a current for returning the shake of the balance beam 19. When an electric current flows through the coil 28, an electromagnetic force is generated, and the magnet 27 moves to the original reference position by this electromagnetic force, and thereby the shake of the balance beam 19 is compensated.

  During this compensation operation, the current i0 supplied to the coil 28 corresponds to a return moment acting on the balance beam 19, and the return moment corresponds to an increase / decrease amount of the weight of the sample. Therefore, by measuring the TG output voltage corresponding to the current i0, the weight change of the sample is measured, ie, weighed. The measurement result is displayed by the display device 37. For example, it is displayed in the form of a graph in which the horizontal axis represents temperature change and the vertical axis represents weight change. The measurer can determine the temperature characteristic of the sample by observing this graph.

(Automatic sample exchange function)
As described above, when the TG measurement is completed for one sample, the TG measurement is performed for a different sample. In this case, the sample on the heat sensitive plate 21 needs to be exchanged. In this embodiment, the replacement can be performed automatically and continuously using the sample changer 2 of FIG.

  FIG. 5 shows a flow of operation when the sample changer 2 automatically changes the specimen. In FIG. 4, when the sample change signal S1 is sent to the sample change control circuit 39, the sample change control circuit 39 executes the automatic sample change operation shown in FIG. That is, in the process P1, the furnace moving device 26 in FIG. 2 is operated, and the electric furnace 24 in FIG. 3 is moved from the measurement position indicated by the chain line to the sample opening position indicated by the solid line.

  Next, in step P2 of FIG. 5, the sample is held and transported. Specifically, in FIG. 2, the arm lifting / lowering device 12 is operated to lower the transfer arm 7, and the lower end of the finger 13 is lowered to the left and right sides of the sample container 4. Next, the opening / closing drive device 14 is actuated to close the finger 13 and grip the sample container 4. Next, the arm elevating device 12 is operated to raise the transfer arm 7, and the arm rotating device 11 is further operated to rotate the transfer arm 7 as indicated by an arrow A. Accordingly, the finger 13 holding the sample container 4 is carried to a position above the heat sensitive plate 21 at the tip of the balance beam 19 of the balance device 3.

  Next, in the process P3 of FIG. 5, the arm lifting / lowering device 12 of FIG. 2 operates and the transfer arm 7 is lowered. In this way, the sample container 4 held by the fingers 13 and 13 is placed at a position directly above the heat sensitive plate 21.

  Next, in step P4 of FIG. 5, the fingers 13 and 13 of FIG. 2 are driven and opened by the opening / closing drive device 14, whereby the sample container 4 is placed on the heat sensitive plate 12. Further, in step P5 of FIG. 5, the arm lifting device 12 of FIG. 2 operates to raise the transfer arm 7, and the arm rotation device 11 operates to return the transfer arm 7 to the turntable 6. Thereafter, the TG measurement operation already described is executed in a timely manner. Then, by repeating the series of operations described above, TG measurement is automatically performed on a plurality of samples.

  By the way, in the thermal analyzer, there may be a phenomenon in which the thermal plate 21 and the sample container 4 placed on the thermal plate 21 adhere to each other for some reason. In such a case, when the sample container 4 is lifted from the heat sensitive plate 21 in FIG. 1, the heat sensitive plate 21 attached to the sample container 4 may be lifted together. As a result, the position of the heat sensitive plate 21 is shifted. Or the heat sensitive plate 21 may be inclined. Further, when the sample container 4 is placed on the heat sensitive plate 21, the position of the heat sensitive plate 21 is shifted by the finger 13 holding the sample container 4 or the sample container 4 touching the heat sensitive plate 21. There is a possibility that the heat sensitive plate 21 is inclined.

  In particular, when the sample container 4 is automatically attached to and detached from the thermal plate 21 using the sample changer 2 as shown in FIG. 2 as in this embodiment, the position of the thermal plate 21 is once. If they are shifted, the sample changer 2 may malfunction. Specifically, if the position of the heat sensitive plate 21 is shifted or the heat sensitive plate 21 is inclined, the finger 13 of the sample changer 2 erroneously grabs the heat sensitive plate 21 or pushes the heat sensitive plate 21 in the subsequent operation. There was a fear. In this regard, in this embodiment, since the heat sensitive plate 21 is supported by the wire 16 in addition to the thermocouple 15, the mechanical strength for supporting the heat sensitive plate 21 is increased. It is possible to prevent displacement and inclination of the heat sensitive plate 21.

  Further, as shown in FIG. 7B, in the conventional structure in which the heat sensitive plate 121 and the pipe 117 are fixed, the bottom surface of the heat sensitive plate 121 is in direct contact with the pipe 117. In such a case, since the contact area between the heat sensitive plate 121 and the pipe 117 is large, heat may escape from the heat sensitive plate 121 to the balance beam 119 via the pipe 117, and the sensitivity of measurement may be reduced. was there.

  In this regard, in the present embodiment, a space T is provided between the heat sensitive plate 21 and the balance beam 19 as shown in FIG. In this way, heat escape from the heat sensitive plate 21 is prevented so that the heat sensitive plate 21 and the balance beam 19 are not in direct contact with each other. Further, the length L0 of the pipe 17 along the axis X1 direction of the balance beam 19 is set to 3 mm or less. By doing so, the contact area between the wire 16 and the balance beam 19 can be reduced, so that the amount of heat escaping from the heat sensitive plate 21 through the wire 16 to the balance beam 19 can be reduced. Thereby, it can prevent that the sensitivity of a measurement falls.

  Next, in the present embodiment, four projecting pieces 25 for preventing the sample container 4 from falling from the heat sensitive plate 21 are provided. As shown in FIG. 1A, these protrusions 25 are provided on the outer periphery of the heat sensitive plate 21 so as to protrude in the upper surface direction of the heat sensitive plate 21. Further, as shown in FIG. 1B, the projecting piece 25 is provided such that a portion corresponding to the axis X1 of the balance beam 19 is a spacing portion D0. If the plurality of projecting pieces 25 are provided in this manner, the sample container 4 can be gripped at the interval portion D0, so that the sample container 4 can be easily attached and detached.

  Further, the wire 16 is fixed to the two protruding pieces 25 a located on the near side as viewed from the balance beam 19 among the four protruding pieces 25. By doing so, the wire 16 is fixed to the projecting piece 25a closest to the pipe 17, so that the wire 16 having a short and simple shape can be used. Thereby, the structure which supports the thermal plate 21 to the balance beam 19 can be simplified. Moreover, since the wire 16 can be provided in a symmetrical position with respect to the axis of the balance beam 19, the heat sensitive plate 21 can be supported stably.

  Next, the wire 16 that supports the heat sensitive plate 21 can be formed using the same material as the thermocouple 15 disposed inside the balance beam 19. In this way, it is not necessary to form the wire 16 using a new material, so that the material can be saved.

  In the present embodiment, a platinum rhodium alloy is used as the material of the conductive wire constituting the thermocouple 15. Platinum rhodium alloy is a high heat resistant material, and is a material that is not easily oxidized even at high temperatures. Therefore, if the wire 16 is formed using the same platinum rhodium alloy as the thermocouple 15, it is possible to prevent the wire 16 from being oxidized by the heat generated from the electric furnace 24 of FIG. 3 or the heat transmitted from the heat sensitive plate 21. Moreover, since the platinum rhodium alloy can be made into a material that can be easily processed if the rhodium content is lowered, the portion that supports the heat sensitive plate 21 can be easily configured.

  Next, it is desirable that the rhodium content of the platinum rhodium alloy used for the wire 16 is 5 to 40%. The reason is that if it is less than 5%, the platinum rhodium alloy becomes too soft. When the wire 16 is formed using this platinum rhodium alloy, the strength of supporting the heat sensitive plate 21 to the balance beam 19 is low, and the heat sensitive This is because when the sample container 4 is attached to or detached from the plate 21, the position of the heat sensitive plate 21 may move or the heat sensitive plate 21 may tilt. Further, if it exceeds 40%, the platinum rhodium alloy becomes too hard and it becomes difficult to process the wire 16. If the rhodium content of the platinum rhodium alloy is 5 to 40%, the wire 16 that can be easily processed can be formed, and the strength of supporting the heat sensitive plate 21 on the balance beam 19 can be increased.

(Other embodiments)
The present invention has been described with reference to the preferred embodiments. However, the present invention is not limited to the embodiments, and various modifications can be made within the scope of the invention described in the claims.

  For example, in the embodiment described above, as shown in FIGS. 1A and 1B, the four protruding pieces 25 of the heat sensitive plate 21 are provided. However, a plurality of projecting pieces 25 other than four may be provided as long as the spacing portion D0 can be provided in the portion corresponding to the axis X1 of the balance beam 19.

  Further, in the above embodiment, the pipe 17 is used as an element for engaging the wire 16 with the beam for heaven. However, such elements can also be realized by elements other than pipes. For example, the same metal material as that of the pipe 17 may be attached to the balance beam 19 by vapor deposition or plating, and the wire 16 may be fixed to the attachment element. In this case, the thickness of the attachment element can be less than 0.1 mm.

  In the above-described embodiment, the wire 16 having a circular cross-sectional shape is used. However, a wire 16 having a square shape, a triangular shape, an elliptical shape, or other shapes other than the circular shape may be used.

  Moreover, in said embodiment, when replacing | exchanging the sample container 4, the case where the replacement | exchange operation | work was automatically performed using the sample changer 2 shown in FIG. 2 was shown. In this case, the sample container 4 is held by the finger 13 and is attached to and detached from the heat sensitive plate 21. However, the exchange operation of the sample container 4 can also be performed manually. In this case, the sample container 4 can be gripped by using tweezers instead of the finger 13, and the sample container 4 can be attached to and detached from the thermal plate 21.

  Moreover, in said embodiment, the TG apparatus of the system which uses one balance beam 19 was illustrated. However, the present invention can also be applied to a TG apparatus using a balance beam for a measurement sample and a balance beam for a standard material. Further, the present invention has a structure using a balance beam, and can be applied to any kind of thermal analysis apparatus in which a sample is placed on the balance beam. Further, the present invention can also be applied to any kind of thermal analysis apparatus that uses a member other than the balance beam as a support rod.

  The present invention is preferably used when it is necessary to attach and detach a sample in a thermal analysis apparatus having a structure using a support rod such as a balance beam, for example, a TG apparatus. The present invention is also useful when using a sample changer that has a function of automatically exchanging samples.

It is a figure which shows the sample mounting part of the thermal analyzer which concerns on this invention, (a) shows the side view, (b) has shown the top view. It is a perspective view which shows one Embodiment of the thermal analyzer which concerns on this invention. It is a figure which shows a part of thermal analyzer of FIG. It is a block diagram which shows an example of the electric control system used for the thermal analyzer of FIG. It is process drawing which shows an example of operation | movement of the thermal analyzer of FIG. It is a block diagram which shows the internal structure of the PID control circuit used with the thermal analyzer of FIG. It is a figure which shows two examples of the conventional thermal analyzer.

Explanation of symbols

1. 1. TG device (thermal analysis device) 2. Sample changer Balance device,
4). Sample container, 6. 6. turntable 8. transfer arm; Spindle,
13. Fingers, 14. 15. Finger opening / closing drive device, Thermocouple, 16. Wire,
17. Pipes, 18. Torsion band,
19, 19a, 19b. Balance beam (support bar), 20. Socket, 21. Thermal plate, 24. Electric furnace, 25, 25a. Protrusion, 27. Permanent magnets, 28. coil,
31. Light shielding plate, 32. Light source, 33. Light receiving element, 44. Stopper,
i0. Coil current, P0. Sample removal position, T.P. space

Claims (7)

A thermal plate on which the sample is placed;
A thermocouple having a temperature measuring part fixed to the heat sensitive plate;
A support rod for supporting the thermocouple;
A wire having one end fixed to the heat sensitive plate and the other end engaged with the support rod;
A thermal analyzer, wherein a space is provided between the heat sensitive plate and the support rod.   The thermal analysis apparatus according to claim 1, further comprising: a pipe that is fitted to an end portion of the support rod, wherein the wire is engaged with the support rod through the pipe, and the axial direction of the support rod of the pipe The thermal analysis apparatus characterized by the length along 3 being 3 mm or less.   3. The thermal analysis apparatus according to claim 1, wherein the thermal plate is provided with a plurality of projecting pieces arranged so as to project outward and a portion corresponding to the axis of the support bar is an interval portion. The wire is provided on both sides of the support rod across the axis of the support rod, and each wire is fixed to one of the plurality of projecting pieces.   4. The thermal analysis apparatus according to claim 3, wherein four protrusions are provided, and the wires are fixed to two protrusions on the front side when viewed from the support rod.   5. The thermal analysis apparatus according to claim 1, wherein the wire is made of the same material as the thermocouple. 6.   The thermal analyzer according to any one of claims 1 to 5, wherein the wire has the same cross-sectional shape as the thermocouple. The thermal analyzer according to any one of claims 1 to 6, wherein the wire is made of a platinum rhodium alloy having a rhodium content of 5 to 40%.

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