JPS6250765B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION As thermobalances become more widespread, higher sensitivity and higher precision are required. However, since the sample is placed in a heating furnace, the apparent weight of the sample changes due to gas convection and fluctuations in buoyancy. Errors in weight detection due to this are caused by the shape, size, temperature, type of gas, furnace structure, and shape of the sample and its support.
It is extremely difficult to correct because it changes in a complicated manner depending on the rate of change of temperature, pressure, etc. Accordingly, the present invention provides a self-balancing thermobalance that can perform highly sensitive measurements without causing errors due to convection and buoyancy, has a simple structure, and is easy to manufacture and adjust.

FIG. 1 is a front view of an embodiment of the present invention, in which the central portions of support rods 5 and 6 are suspended from support points 3 and 4 at both ends of a balance arm 2 supported by a support point 1. The upper parts of the support rods 5 and 6 are bent in the direction of the fulcrum 1 of the balance, and the support rods 7 and 8 are vertically connected to the tips of the support rods.
is installed. In addition, flexible cables 13 and 1 are tied at one end to fixed parts 11 and 12 and stretched horizontally, respectively.
4 is tied to the lower ends of the support rods 5 and 6, so that the support rods 5 and 6 are arranged vertically, and the sample container 9 and the standard sample container 10 are arranged above the fulcrum 1. It is housed in one furnace 15. Furthermore, a magnetic core 16 attached to one support rod 5
is fitted into the coil 17 of a differential transformer, and a magnet 18 attached to the support rod 7 is fitted into a control coil 19, and the output of the differential transformer is amplified by an amplifier 20 and applied to the coil 19. The flexible cables 13 and 14 are made of extremely thin tungsten wire with a diameter of about 0.1 mm, for example, and their ends are held down by a holding plate 21 and tightened with screws 22 to form a support rod or a fixed part. It is easily connected to.
In addition, in the device shown in FIG. 1, the flexible cables 13 and 14 are strung in parallel on the same vertical plane with a minute interval, but as shown in the plan view of this part in FIG. It can also be placed on a horizontal plane.

In the above-mentioned apparatus, the center of gravity of the support rods 5, 6 and the sample containers 9, standard sample containers 10, etc. attached thereto is located between the fulcrums 3 or 4 and the fulcrum 1, so there is always an arrow mark at the lower end of the support rods. Forces in the directions indicated by p and q are applied. Therefore, by stretching the flexible cables 13, 14 over the lower ends of the support rods 5, 6, the support rods can be held vertically. And if the balance arm 2 is tilted due to a change in the weight of the sample,
By moving the magnetic core 16, the coil 1 of the differential transformer
Output is sent from 7. Since this output is amplified and applied to the coil 19, the magnet 18 is pulled in a direction that compensates for the above-mentioned inclination, and this negative feedback action keeps the balance always in an equilibrium state, and the output of the amplifier 20 increases the weight of the sample. Changes can be measured.

As described above, in the apparatus of the present invention, the center of gravity of the support rods 5 and 6 that support the sample etc. is located between the fulcrum 1 of the balance and the fulcrums 3 or 4 at both ends of the arm 2, and in the case of an automatic balancing thermobalance, the center of gravity of the support rods 5 and 6 supporting the sample etc. Taking advantage of the fact that the support rod is always maintained in a horizontal state, the support rod is always held vertically by an extremely simple structure in which the end of the support rod is pulled by a flexible cable.
In addition, since the flexible cable is stretched horizontally, there is no risk of vertical force being applied to the tip of the arm of the balance by the flexible cable, and by making the flexible cable sufficiently long, Disadvantages such as reduced sensitivity of the balance are also eliminated. Moreover, since the support rod always maintains a vertical state, by bending its end in the direction of fulcrum 1 and placing both the sample and standard sample near the vertical line passing through the fulcrum, they can be placed in the same furnace. can be accommodated within. Therefore, errors due to fluctuations in gas convection or buoyancy in the furnace can be prevented. Moreover, since the structure is simple as described above, manufacturing, adjustment, etc. are also easy.

[Brief explanation of the drawing]

FIG. 1 is a front view of an embodiment of the invention, and FIG. 2 is a partially sectional plan view of another embodiment of the invention. In the figure, 1 is the fulcrum of the balance, 2 is the arm of the balance, 3 and 4 are the fulcrums, 5 and 6 are the support rods, and 7 and 8
is a support rod, 9 is a sample container, 10 is a standard sample container,
11 and 12 are fixed parts, 13 and 14 are flexible cables, and 15
1 is a furnace, 16 is a magnetic core, 17 is a differential transformer coil, 18 is a magnet, 19 is a control coil, 20 is an amplifier, and 21 is a holding plate.

Claims (1)

[Claims] 1 Suspend support rods at both ends of the balance arms,
One end of each of the support rods is bent in the direction of the fulcrum of the balance, and the tips of the support rods support the sample and standard sample, respectively, and one end of each support rod is tied to a fixed part and stretched horizontally. The other ends of the flexible cables were tied to the other ends of the two support rods, so that the support rods were arranged vertically, and the sample and standard sample were housed in the same furnace. A self-balancing thermobalance characterized by: