JP3129517B2 - Thermobalance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic balance type thermobalance and, more particularly, to an improvement in a thermobalance which is reduced in weight by using a flexible cable.

[0002]

2. Description of the Related Art Conventionally, as a thermal balance, for example, as shown in FIG. 2, sub-fulcrum points 3 and 4 are provided at both ends of an arm 2 of a balance having a main fulcrum 1 at a center portion. The upper ends of the pair of auxiliary arms 5 and 6 supported and raised are brought close to each other above the main fulcrum side of the balance, and a pair of sample holders 7 respectively raised from the upper ends of the adjacent auxiliary arms 5 and 6. , 8 in which the sample 9 and the standard sample 10 are
1, while the auxiliary arms 5 and 6 are always maintained in an equilibrium state by an automatic balance device such as a magnetic force type (not shown), and a differential thermogravimetric analysis is performed based on the output of the automatic balance device. Structures are known.

Further, in the thermobalance having such a structure, since the upper ends of the auxiliary arms 5 and 6 are close to each other above the main fulcrum side of the balance, the center of gravity of the auxiliary arm itself and the position of the sample are measured. Since the auxiliary arms 5 and 6 always rotate due to the added weight, it is necessary to adopt a structure for preventing the rotation.

Conventionally, as a structure for preventing the rotation of the auxiliary arms 5 and 6, a structure in which the lower ends of the auxiliary arms 5 and 6 are connected to each other by a link mechanism has been often adopted. Due to the increase in weight, in recent years, as shown in FIG. 2, a cable support structure has been developed in which the rotation of the auxiliary arms 5, 6 is prevented by flexible cables 13, 14 attached to a fixing portion 12 such as a frame. I have.

[0005]

However, in the above-described conventional structure, as shown in FIG.
Is limited to half the distance between the auxiliary arms 5 and 6, the vertical component ΔW (= Tsi
nθ: T is the tension of the flexible cable). In order to reduce the vertical component, it is necessary to lengthen the flexible cables 13 and 14.

Therefore, as a means for lengthening the flexible cables 13 and 14, hitherto, as shown in, for example, Japanese Patent Publication No. 62-50765, a fixing portion is arranged independently for each flexible cable and each flexible cable is provided. It has been considered to separate the bending cable up and down or left and right so as not to interfere.

However, with such a configuration, the flexible cables are vertically or horizontally shifted from each other, so that the position at which the flexible cables are attached to the auxiliary arm is deviated. There is a possibility that a problem such as a decrease in measurement accuracy due to the application of a torsional force may occur.

The present invention has been made to solve such a problem, and an object of the present invention is to increase the length of a flexible cable without applying a twisting force or the like to an auxiliary arm, thereby improving the measurement accuracy. An object of the present invention is to provide a thermobalance that can be improved.

[0009]

In order to achieve the above-mentioned object, the present invention provides a balance arm having a main fulcrum at the center and sub-fulcrums provided at both ends of a balance arm. The upper ends of the pair of auxiliary arms are brought closer to each other above the main fulcrum side of the balance, and the sample and the standard sample are placed in a pair of sample holders rising from the upper ends of the adjacent auxiliary arms in the same heating furnace. A cable support structure for supporting the two auxiliary arms from a fixed side via a flexible cable so as to regulate the rotation of the two auxiliary arms and maintain a constant interval between the upper ends thereof; In a thermobalance in which an auxiliary arm is always maintained in an equilibrium state by an automatic equilibrium device and a differential thermogravimetric analysis is performed based on an output of the automatic equilibrium device, a flexible cable of the cable support structure is connected to an upper end of each of the auxiliary arms. Or It is made by extending in a direction away from each other toward the anti-principal fulcrum.

[0010]

According to the present invention, the flexible cables constituting the cable support structure for preventing the rotation of both auxiliary arms are stretched in the directions away from the upper ends of the respective auxiliary arms, so that the flexible cables can be sufficiently extended. It is possible to arrange them at the same height and on the same plane without mutual interference while ensuring a sufficient length.

[0011] Therefore, the connecting position of the flexible cable to the two auxiliary arms can also be arranged at the same height and on the same plane. Measurement becomes possible.

[0012]

An embodiment of the present invention will be described below with reference to FIG.

As shown in FIG. 1, in the thermal balance of this embodiment, auxiliary fulcrums 23 and 24 are provided at both ends of a balance arm 22 having a main fulcrum 21 at the center. Each sub-fulcrum 2
Auxiliary arms 25 and 26 are respectively supported on the reference numerals 3 and 24, and the respective auxiliary arms 25 and 26 are inclined and rise up with their upper ends close to each other. In addition, each auxiliary arm 2
A pair of sample holders 27 and 28 rise vertically at the upper ends of the sample holders 5 and 26, respectively. At the upper end of each of the sample holders 27 and 28, a sample 29 and a standard sample 30 are placed in the same heating furnace, for example, an electric furnace 31. Supported by.

Each of the auxiliary arms 25 and 26 is provided with a cable support structure 41 for preventing the rotation thereof. That is, the rope support structure 41 is formed by connecting a pair of flexible ropes, for example, wires 42 and 43, each having one end to the upper end of each of the auxiliary arms 25 and 26, and each other end of each of the wires 42 and 43. A fixing part 44 to be fixed to a fixing system such as a frame,
45. The wires 42, 43 of the cable support structure 41 are connected to the respective auxiliary arms 25, 26.
Extend from the upper end toward the opposite main fulcrum 21 side.

On the other hand, below the main fulcrum 21 of the balance, there is provided an automatic balancing device 32 for keeping the auxiliary arms 25 and 26 always in a balanced state. That is, the automatic balancing device 32 includes a hanging arm 33 that is integrally hung from the center of the balance arm 22, a shutter 34 provided at a lower end of the hanging arm 33, and a light shielding amount that changes according to the inclination angle of the shutter 34. Angle detector 37 composed of a light source 35 and a light receiving element 36, and a magnet 38 attached to a hanging arm 33 and an electromagnetic actuator 40 composed of a solenoid 39 attached to a frame (not shown) forming a fixed system. And a feedback circuit (not shown) for holding the hanging arm 33 vertically by magnetic adjustment of the operation of the actuator 40 in accordance with an output signal from the tilt angle detecting section 37.

Although not shown, an adjustment magnetic force for maintaining the equilibrium state of each of the auxiliary arms 25 and 26 by the feedback circuit unit is detected in association with the automatic balancing device 32, and thereby a differential thermogravimetric analysis is performed. Is provided.

In the thermobalance constructed as described above,
If the sample 29 in the electric furnace 31 changes in weight during measurement, the sample holder 27 (28) and the auxiliary arm 25 (26) on the heavier side move downward, while the sample holder and the auxiliary The arm moves up,
The inclination of the arm 22 of the balance due to this is detected by a change in the amount of light shielding between the light source 35 and the light receiving element 36 by the shutter 34 of the inclination angle detection unit 37, and furthermore, a feedback circuit according to an output signal from the inclination angle detection unit 37. The magnetic adjustment of the electromagnetic actuator 40 is performed by the
Is held vertically, and at this time, a differential thermogravimetric analysis is performed by the calculation unit.

According to the present embodiment, the wires 42, 43 constituting the cable support structure 41 for preventing the rotation of the auxiliary arms 25, 26 are moved in the direction away from the upper ends of the auxiliary arms 25, 26. Because it is stretched toward
These wires 42 and 43 do not interfere with each other.
Therefore, the wires 42, 43 can be arranged at the same height and in the same plane while ensuring a sufficient length thereof, so that the auxiliary arms 25, 2 of the wires 42, 43 can be provided.
6 can also be arranged at the same height and on the same plane.

That is, according to the present embodiment, the wire 4
The coupling positions of the auxiliary arms 25 and 26 with respect to the auxiliary arms 25 and 26 can also be coaxially arranged. Unlike the conventional structure, there is no possibility that the auxiliary arms 25 and 26 will be affected by torsion or the like at the time of measurement. It allows measurement.

In the above embodiment, the automatic balancing device 32
Is provided below the balance, but the arrangement may be set at another position.

In the above embodiment, the automatic balancing device 32
Although the tilt angle detection unit 37 of the above is an optical configuration including the light source 35 and the light receiving element 36, it can be appropriately modified such as an electromagnetic configuration.

[0022]

As described above, according to the present invention, the flexible cables constituting the cable supporting structure for preventing the rotation of the two auxiliary arms are stretched in the directions away from the upper ends of the respective auxiliary arms. Therefore, it is possible to make the same height and the same plane arrangement while securing a sufficient length by eliminating interference between the flexible cables, and therefore, there is no possibility that the auxiliary arm will be affected by torsion or the like at the time of measurement, An excellent effect that high-precision measurement is possible is achieved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a thermobalance according to the present invention.

FIG. 2 is a configuration diagram showing a conventional thermobalance.

FIG. 3 is an explanatory diagram showing an enlarged operation of a portion A in FIG. 2;

[Explanation of symbols]

21 Main fulcrum 22 Arm of balance
23, 24 Secondary fulcrum 25, 26 Auxiliary arm 27, 28 Sample holder
29 samples 30 standard samples 31 electric furnace (heating furnace)
32 Automatic balancing device 41 Cable support structure 42, 43 Flexible cable
44, 45 Fixed part

Claims (1)

(57) [Claims] An auxiliary arm is provided at each end of an arm of a balance having a main fulcrum at the center, and the upper ends of a pair of auxiliary arms supported and supported by the auxiliary fulcrum are attached to the main fulcrum side of the balance. The sample and the standard sample are supported in the same heating furnace by a pair of sample holders which are brought up and approached from the upper ends of the adjacent auxiliary arms, respectively. A cable support structure for supporting the auxiliary arms from a fixed side via a flexible cable so as to keep the interval between the parts constant is provided, and the auxiliary arms are always kept in an equilibrium state by an automatic equilibrium device. In a thermobalance for performing differential thermogravimetric analysis based on the output of the automatic balancer, the flexible cables of the cable support structure are extended from the upper ends of the auxiliary arms in directions away from each other toward the opposite main fulcrum side. Was it Thermobalance characterized by the following.