JPS63290939A - Thermobalance device - Google Patents

Abstract

PURPOSE:To increase sensitivity by using two balance systems and increasing the length of one arm of each balance system while making the length of the other arm constant and holding support levers supported atop of those arms constant, as it is in horizontal length. CONSTITUTION:A sample holder 8 and a standard sample holder 21 are suspended from the long arm parts 3 and 17 of a 1st balance 2 and a 2nd balance 26 which have the same sensitivity through the supporting levers 5 and 20 and put in a heating furnace 11. A point P which is on the long arm, 17 of the 2nd balance 26 and at the distance of the short arm 14 of the 1st balance 2 from a fulcrum 18 is coupled with the top of the short arm 14 of the 1st balance 2 by a coupling lever 15. Consequently, said two balances can be balanced, so when a sample and a standard sample are applied with the same force owing to variation in convection or buoyancy in heating, it is never as variation in weight. Fine weight variation is therefore measured with high accuracy.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thermobalance device, and is particularly concerned with errors caused by changes in convection and buoyancy within a heating furnace during temperature rise and fall [Prior Art] This type of As a thermobalance, for example, Japanese Patent Publication No. 54-27158 and Japanese Patent Publication No. 54. The one described in Japanese Patent No. 271.59 is known.

In the system described in Japanese Patent Publication No. 54-27158, fulcrums are provided at the ends of both arms of a main balance, and a sub-balance is suspended from each fulcrum, and one arm of each sub-balance is attached vertically through the fulcrum of the main balance. The sample and the standard sample are placed in the same furnace by suspending the sample and the standard sample from the tip of each arm, each extending close to the line.

In addition, what is described in Japanese Patent Publication No. 54-27159 is
A connecting rod of the same length as the arm of the balance is placed parallel to the arm, and the connecting rod is rotatably tied to the point where a vertical line passing through the fulcrum of the balance intersects with the connecting rod. 2 placed in
The book support rods are rotatably tied to both ends of the arms of the balance and the connecting rods to form a link mechanism, and the support rods are bent to attach the sample and standard sample to their tips. These are housed in the same furnace by arranging them near the vertical line.

In all of these conventional thermobalance devices, when the same force is applied to the sample and the standard sample, these forces act on the tips of both arms of the balance and cancel out, so it does not appear as a weight change. do not have. Therefore, for example, even if a change occurs in the convection in the heating furnace or the buoyancy of the sample during the process of raising or lowering the temperature of the heating furnace in which the sample and standard sample are housed, these changes will cause Since the forces acting on the sample and the standard sample are almost the same, these forces cancel out and do not appear as a weight change. On the other hand, if a weight change occurs in either the sample or the standard sample, the weight change can be detected in the same way as a normal balance. As a result, even if the balance is made highly sensitive, it will not be affected by convection or buoyancy, making it possible to measure minute changes in weight with relatively high precision.

[Problems to be Solved by the Invention] However, in order to house the sample and the standard sample in the same furnace, these conventional thermobalance devices
In the device described in Publication No. 58, one arm of each sub-balance suspended on both arms of the main balance is extended to the vicinity of a vertical line passing through the fulcrum of the main balance, and a Kosho 5
In the case of No. 4-27159, the support rods rotatably attached to both arms of the balance are bent and extended to the vicinity of a vertical line passing through the fulcrum of the balance, and the sample is attached to the tip of these rods. The structure is such that the standard sample and the standard sample are suspended.

That is, according to this configuration, the length of one arm of the sub-balance, or the length of the bent and extended arm of the support rod, is necessarily the same as that of the main balance or one arm of the balance. It should be approximately the same length as the length. Therefore, if the length of the arm of the balance is increased in order to make the balance highly sensitive, the arm of the sub-balance or the arm of the support rod will also be lengthened accordingly. Then, in the system described in Japanese Patent Publication No. 54-271.58, the weight 9 suspended on the other arm of the sub-balance must be made that much heavier for balance, making the entire balance system heavier. This results in a decrease in sensitivity, which largely cancels out the effect of improving sensitivity by lengthening the arm of the main balance. Furthermore, in the device described in Japanese Patent Publication No. 54-27159, it is necessary to lengthen the arm of the support rod by the length of the arm of the balance, and the increased moment due to the lengthening of the arm of the balance is proportional to the length of the arm of the balance. The weight increases, making the entire balance system heavier, and the vertical force acting on the support rod (5) by the connecting rod (3) when the balance is about to swing also increases by the increase in moment, causing Since the force acting on each fulcrum of the connecting rod (3) also increases, the frictional force at each fulcrum also increases, which ultimately cancels out the effect of improving sensitivity by lengthening the arms of the balance.

As described above, all of the above-mentioned conventional thermobalance devices have a certain limit in increasing their sensitivity.

An object of the present invention is to eliminate the drawbacks of the conventional thermobalance device, and to provide a thermobalance device that is capable of achieving higher sensitivity and higher accuracy.

[Means for Solving the Problems] The thermobalance device according to the present invention uses two balance systems, one arm of each balance system has a constant length, and a support supported at the tip of each arm is used. By keeping the horizontal length of the rod constant and making the other arm sufficiently long, it is possible to achieve even higher sensitivity and precision. Specifically, a first balance supported on a first fixed fulcrum;
a second balance supported on a fixed fulcrum;
The balance has a long arm provided on one side of the first fixed fulcrum, a short arm provided on the other side, and a first movable fulcrum provided at the tip of the long arm. It has a first support rod rotatably supported by the first moving fulcrum and disposed vertically, and one end of the first support rod is bent and extended in the horizontal direction. A first sample holder is attached to the tip of the holder, and the other end has a constant distance from the point where a horizontal line passing through the end intersects a vertical line passing through the first fixed fulcrum. The second balance is supported by a first regulating means that rotatably regulates the end portion such that The balance is installed at a position where the distance from the intersection of the vertical line passing through the tip of the arm and the horizontal line passing through the second fixed fulcrum to the fixed fulcrum is the same as the length of the short arm of the first balance, and an arm having the same length as the long arm of the first balance and having one end supported by the second fixed fulcrum, and a second movable fulcrum provided at the other end of the arm;
It has a second support rod rotatably supported by the second moving fulcrum and disposed vertically, and the second support rod has one end bent and extended in the horizontal direction. A second sample holder is attached to the tip, and the distance between a point on the vertical part near the bent part and the intersection of a horizontal line passing through the chain point and a vertical line passing through the second fixed fulcrum is constant. It is supported by a second regulating means for rotatably regulating the chain point so that the chain point is rotatably controlled, and the vertical line passing through the tip of the short arm of the first balance and the tip of the short arm of the second balance is The intersection points intersecting the arms are connected by a third regulating means that rotatably regulates the distance between them so that the distance between them is constant, and the third regulating means is attached to the tips of the first and second sample holders. It has a configuration in which the sample to be measured and the standard sample are housed in the same furnace.

[Function] The first balance balances when the load applied to the tips of the long arm and the short arm reaches a predetermined ratio, and the second balance balances the load applied to the tip of the second moving fulcrum and the load applied to the tip of the short arm. Balance occurs when the forces acting on the tip of the short arm of the first balance and the intersection point (hereinafter referred to as 9 points) where the vertical line passing through the tip intersects with the arm of the second balance reach a predetermined ratio. The force acting on the nine points of the second balance is the load itself applied to the tip of the short arm of the first balance. Moreover, since the length of the arm that determines the sensitivity of each balance is the same, the first balance and the second balance have almost the same sensitivity.

Therefore, when the same force is applied to each of the material holders, these forces are canceled out by the action of the second regulating means and do not cause any change in either balance system. On the other hand, if different forces are applied to each of the sample holders, the difference between these forces is detected as a weight change. Furthermore, the arms of each balance, each support rod, and each regulating means constitute a so-called donkey pal mechanism for each balance system, so even if each balance system is tilted, each support rod is held almost vertically. There is no problem with measurement. By keeping the length of the short arm constant, keeping the length of the horizontal extension of the support rod constant, and making the length of the long arm sufficiently long, the thermobalance is extremely sensitive compared to conventional thermobalance devices. It can be made into a device.

Figure 1 shows the configuration of the first embodiment of the invention, Figure 2 shows the configuration of the second embodiment of the invention, and Figure 3 shows the third embodiment of the invention. FIG. 3 is a diagram showing an example configuration.

In Fig. 1, supported by the first fixed fulcrum 1 = 10
= A first movable fulcrum 4 is provided at the tip of one long arm 3 of the first balance 2, and a first support rod 5 disposed perpendicularly to this first movable fulcrum 4 is rotatable. is supported by

The first support rod 5 has arms 6 and 7 extending vertically from the first moving fulcrum 4, and the upper end of the arm 6 is bent to extend parallel to the arm 3 of the first balance 2. It extends toward the first fixed fulcrum 1, and a first sample holder 8 is fixed to its tip. This sample boulder 8 is composed of an elongated rod 9 made of a heat-resistant material such as alumina whose lower end is fixed to the sample holder, and a first sample dish 10 which is fixed to the upper end of this rod. This sample dish 10 is placed inside a heating furnace 11. On the other hand, one end of a wire 12 serving as a first regulating means is fixed to the lower end of the arm 7 on the lower side of the first support rod 5, and the wire 12 runs parallel to the arm 3 of the first balance 2. The other end is fixed to a fixed part 13 which is extended and lies on a vertical line passing through the first fixed fulcrum 1.

Further, the other arm 14 of the first balance 2 is formed shorter than the -11= one arm 3, and a wire 15 serving as a third regulating means is attached to its tip, that is, the right end in the figure. One end of the wire 15 is fixed, and the wire 15 is extended vertically downward and the other end is fixed to one long arm 17 of a second balance 16. This second balance 16 has a second portion of its arm 17 located to the right in the figure by the length of the other short arm 14 of the first balance from the point p where the other end of the wire 15 is fixed. It is supported by a fixed fulcrum 18. Also,
The length of the arm 17 of the second balance 16, that is, the length from the second fixed fulcrum 18 to the left end in the figure, or the first
It is formed to have the same length as the long arm 3 of the balance 2. That is, if the length of one arm 3 of the first balance 2 is a and the length of the other arm 14 is b, then the length of one arm 17 of the second balance, that is, the length of the other arm 14 is The length from the second fixed fulcrum 18 to the left end in the figure is a, and the length from the second fixed fulcrum 18 to point p is b.

One second movable fulcrum is provided at the left end in the figure of the arm 17 of the second balance 16, and a second support disposed perpendicularly to this second movable fulcrum 19 is provided. Rod 20
It is rotatably supported. The upper end of the second support rod 20 is bent to the left in the figure symmetrically with the upper arm 6 of the first support rod 5 and extends parallel to the arm 3 of the first balance 2, A second sample holder 21 is fixed to the tip of the second support rod 20, and one end of a wire 22 serving as a second regulating means is fixed to the upper part of the second support rod 20.
The other end is a fixed point 23 that extends parallel to the arm 17 of the second balance 16 and intersects with a vertical line passing through the second fixed fulcrum 18.
is fixed. Like the first sample boulder 8, the second sample holder 21 consists of a rod 24 and a second sample pan 25 fixed to the upper end of the rod 24. are housed in the heating furnace 11 and arranged symmetrically with the first sample dish 10 . Note that the second balance 16 has another arm 26 extending toward the right in the figure of the second fixed fulcrum 18 by the same length as the other arm 14 of the first balance 2. The weight of the first and second balance systems is balanced. A detection rod 27 for detecting the inclination of the first balance is fixed to the fixed fulcrum 1 of the first balance 2, and a displacement detector 28 for detecting the displacement of this detection rod 27 is fixed. and an arm 17 of the second balance 16
Two magnets are fixed at point p, and are fitted into the control coil 30. That is, the displacement detector 28 and the control coil 30 are connected to an external control circuit (not shown), and the displacement detector 28 and the control coil 30 are connected to an external control circuit (not shown). A compensation current is caused to flow through the control coil 30, and this compensation current is detected as a weight change.

In the above-mentioned configuration, the first balance 2 is balanced when the loads applied to the tips of the long arm 3 and the short arm 14 reach a predetermined ratio, and the second balance 16 is balanced when the weights applied to the ends of the long arm 3 and the short arm 14 reach a predetermined ratio.
Balance occurs when the load applied to point 9 and the force acting on point p reach a predetermined ratio. The force acting on point p of the second balance 16 is the -14 = weight applied to the tip of the short arm 14 of the first balance 2. In addition, since the relationship between the distance between the force point of each balance and the fulcrum is as shown in Figure 1, the first
The balance 2 and the second balance 16 have almost the same sensitivity. Therefore, when the same force is applied to the sample holters 8 and 21, these forces are canceled out by the action of the wire 15 and do not cause any change in either balance system. On the other hand, when different forces are applied to the sample holters 8 and 21, it is detected as a difference between these forces or a weight change. In addition, the arms, support rods, and wires of each of the balances constitute a so-called donkey pallet for each balance system, so even if each balance system is tilted, each support rod is held almost vertically. It does not cause any trouble to the measurement.

When measuring thermogravimetric changes using this thermobalance device,
First, the first balance 2 and the second balance 16 are adjusted so that they are balanced, and then the sample plate 10 is filled with the paper to be measured whose weight changes when heated, and the sample plate 25 is heated to cause the weight to change. A standard sample R that does not cause any change is filled and heated in a heating furnace 11. Thereby, it is possible to detect when a weight change occurs in the sample S to be measured at a predetermined temperature.

The first embodiment described above has the following advantages.

That is, by using two balances with approximately the same sensitivity, suspending a sample and a standard sample through a support rod at the force points of each long arm, and connecting the force points of each short arm. Since the two balances are balanced, even if the same force is applied to the sample and standard sample due to changes in convection or buoyancy when heating them, this will not be detected as a weight change. do not have.

Therefore, minute changes in weight can be measured with extremely high precision without being affected by convection or buoyancy. Also, since the distance in the horizontal direction between the tips (points of force) of the long arms of each balance, that is, the distance between the vertically arranged support rods, is twice the length of the short arm of each balance, this In order to accommodate the sample fixed to the equal support rod and the standard sample in the same furnace, the distance C must be extended by bending the support rod - 16 = smaller than the length b of the short arm of the register balance Well, that's it. This point provides an extremely important advantage that cannot be achieved with the conventional balances of this type. That is, as the distance c increases, the tension acting on the wires 12 and 22 increases to cancel the increased moment, and the force acting on the force point of each balance increases accordingly, so that the mass of the entire balance system ultimately decreases. becomes large, which causes a decrease in the sensitivity of the balance. In conventional balances, when the arms of the balance are lengthened to increase sensitivity, the length corresponding to C increases accordingly, so there is a certain limit to the improvement of sensitivity. On the other hand, in the above embodiment, the length of C is limited only by the length of the short arm, and is not affected by the length of the long arm a, which determines the sensitivity of the balance. However, by making the length of a sufficiently long, it is possible to obtain a balance with high sensitivity, which has not been possible in the past. Furthermore, as the length of C becomes shorter, the vertical force of the wire that acts on each support rod due to the inclination of each balance becomes smaller, so that the deterioration in sensitivity due to this can be suppressed to a low level. Furthermore, since the wires 2 and 22 are used to balance the support rods 5 and 20, for example, instead of using wires, a rigid connecting rod may be used to connect each end of the rigid body to each of the support rods 5 and 20. Compared to the case where it is rotatably supported at the end of the support rod and a fixed point, there is no need to accurately adjust the positional relationship between each fulcrum, so assembly is extremely easy to adjust, and there is no need for fulcrum members, etc. The manufacturing cost is also low.

FIG. 2 is a diagram showing a second embodiment of the present invention.

In this embodiment, instead of using the wires 12 and 22 in the first embodiment, connecting rods 12a and 22a are used.
using the supporting points 12b, 12C and 22b, 22, respectively.
The other configurations are completely the same as those of the first embodiment.

With this configuration as well, the same functions and advantages can be obtained, except for the advantages of using the wire of the first embodiment.

Further, FIG. 3 does not show the third embodiment of the present invention, and this embodiment is a so-called downward hanging type thermobalance by inverting the balance system of the second embodiment. However, the same effects and advantages as in the second embodiment can be obtained.

[Effects of the Invention] As described in detail above, the present invention uses the first and second balances having the same sensitivity to apply force to the point of force provided at the tip of each long arm via the support rod. A sample and a standard sample are each suspended, while a force point provided at the tip of a short arm of a first balance and a point on a long arm of a second balance from the fulcrum of the second balance to the The two balances are balanced by connecting the points of force that are separated by the same distance as the length of the short arm of the first balance, so when heating the sample and standard sample, Even if the same force is applied to them due to changes in convection or buoyancy, it will not be detected as a change in weight. Therefore, minute changes in weight can be measured with high precision without being affected by convection or buoyancy. In addition, the distance in the horizontal direction between the tips fIA (points of force) of the long arms of each balance, that is, the distance between the vertically arranged support rods, or the length of the short arm of each balance. Therefore, in order to accommodate the sample fixed to the support rods and the standard sample in the same furnace, the distance to extend the support rods by bending them is longer than the length of the short arm of each balance. This has the excellent effect of making the entire balance system extremely sensitive by designing the long arms of each balance to be sufficiently long compared to the short arms. .

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a first embodiment of the invention, FIG. 2 is a diagram showing the configuration of a second embodiment of the invention, and FIG. 3 is a diagram showing the configuration of a third embodiment of the invention. It is a diagram. ■...First fixed fulcrum, 2...First balance, 3...
・Long arm of the first balance, 4...First moving fulcrum, 5.
...First support rod, 8...First sample holder, ]1.
... Heating furnace, 12.12a... Wire and connecting rod as first regulating means, 14... Short arm of first balance,
15° 15a...Wire and connecting rod as third regulating means, 16...Second balance, 17...Second balance arm, 18...Second fixed fulcrum, one . . . second moving fulcrum, 20 . . . second support rod, 21 . . . second sample holder, 22. 22a .

Claims (1)

[Claims] It has a first balance supported on a first fixed fulcrum and a second balance supported on a second fixed fulcrum, the first balance being on one side of the first fixed fulcrum. a long arm provided on the other side, a short arm provided on the other side, a first movable fulcrum provided at the tip of the long arm, and a vertical movable arm rotatably supported by the first movable fulcrum. a first support rod disposed at the first support rod, one end of which is bent and extended in the horizontal direction, and a first sample holder is attached to the tip thereof; The other end is rotatably regulated so that the distance from the point where a horizontal line passing through the end intersects with a vertical line passing through the first fixed fulcrum to the other end is constant. The second balance is supported by a first regulating means, and the second fixed fulcrum is between a vertical line passing through the tip of the short arm of the first balance and the second fixed fulcrum. is installed at a position where the distance from the intersection with the horizontal line passing through the horizontal line to the fixed fulcrum is the same as the length of the short arm of the first balance, and has the same length as the long arm of the first balance. an arm having one end supported by the second fixed fulcrum; a second movable fulcrum provided at the other end of the arm; and an arm rotatably supported by the second movable fulcrum and disposed vertically. The second support rod has one end bent and extended in the horizontal direction, a second sample holder is attached to the tip, and the second support rod has a second sample holder attached to the tip thereof, a second regulating means rotatably regulating the point so that the distance between the point on the vertical portion near the point and the intersection of the horizontal line passing through the point and the vertical line passing through the second fixed fulcrum is constant; The distance between the tip of the short arm of the first balance and the point of intersection of the vertical line passing through the tip with the arm of the second balance is fixed. The sample to be measured and the standard sample attached to the tips of the first and second sample holders are housed in the same furnace. A thermobalance device characterized by: