JPH03237324A - Temperature sensor - Google Patents

Abstract

PURPOSE:To evade the influence of a magnetic field and to improve the reliability of this sensor by winding a thin wire where electric resistance is varied attending on the change in temperature spirally and forming a humidity sensing part. CONSTITUTION:The humidity sensing part is formed by winding the thin wire of platinum where electric resistance in varied with the change of temperature spirally at a pi/2<1/2>d pitch to a diameter (d). The thin wire is rewound while the same pitch is maintained to cancel a voltage induced owing to the variation of a magnetic field and when resistance is measured on a DC basis, an error due to the variation of the magnetic field is evaded. Further, spiral sensors which are formed of different kinds of material are brought into thermal contact with each other to obtain two values of the strength of the magnetic field and the temperature.

Description

[Detailed Description of the Invention] Recently, with the practical application of superconducting magnets, the use of high magnetic fields has increased in various fields, but temperature control of each part of the magnet is important from the point of view of safety and energy saving. This is a challenge. However, commonly used thermometers are affected by magnetic fields and their readings vary. In principle, this deviation can be corrected by calibrating each thermometer under a magnetic field, but since the amount of correction also depends on the angle that the thermometer makes with the magnetic field, it is effectively possible to correct this deviation by calibrating each thermometer under a magnetic field. From the calibration results in the magnetic field only when the magnetic fields are parallel or perpendicular, it was only possible to infer the amount of calibration under the conditions where each temperature sensor is installed from the M experiment.

The temperature sensor manufactured according to the present invention is not affected by the magnetic field depending on the direction of the magnetic field.

That is, although calibration in a magnetic field is still required.

If you only know the strength of the magnetic field around the sensor, it is sufficient to make the same correction regardless of the sensor's installation direction. However, it is characterized by not losing reliability.

The present invention is based on the fact that the electrical resistance R of a thin wire in a magnetic field H changes from the electrical resistance R in a zero magnetic field as follows.

R=R・(1+AH,,t+BHfj) However, here H・
・, H are components of parallel and perpendicular magnetic fields whose electrical resistance changes with changes in the direction of Ia & i and the temperature of platinum, etc., respectively, and A and B are constants that do not depend on the magnetic field.

Since A and B generally exist, R has anisotropy, but the diameter d
On the other hand, only those spirally wound with a pitch p of π/ff d are independent of the direction of the magnetic field, as shown below.

As will be clear from this, in this sensor, electric paper tiC
R depends only on the strength of the magnetic field and has no dependence on the direction of the magnetic field.

Therefore, if the target sensor is calibrated for temperature in a magnetic field in any direction, the calibration data can be used as a correction amount by knowing only the strength of the magnetic field at the installation location, and can be used for temperature measurement under magnetic fields. [Example] Let the Ia wire be d, and wind it with a pitch p of π/ff d to form a spiral shape as shown in FIG. 1. If this continues, an induced voltage will appear between the terminals when the magnetic field changes, causing errors in DC measurements. Therefore, if you rewind the wire as shown in Figure 2 while keeping the same pitch, that voltage will be canceled, and even when measuring resistance using direct current, you will be able to recover from errors caused by magnetic field fluctuations. Also different types of N&
In general, the magnetic resistance is different in the 3rd rM, so if multiple (two in Figure 3) spiral sensors made of different materials are placed in thermal contact with each other, the magnetic field strength and temperature can be adjusted. It is also possible to know two values.

[Brief explanation of drawings]

Figure 1 is a perspective view of thin wire wound spirally. Fig. 2 is a perspective view of a thin wire wound in a spiral, including turning. FIG. 3 is a perspective view showing a double arrangement of sensors.

Claims (1)

[Claims] 1. The temperature-sensing part is a thin wire whose electrical resistance changes with changes in temperature, wound spirally so that the pitch p is π/√(2)d with respect to the diameter d. temperature sensor. 2. A temperature sensor in which two or more temperature sensors according to claim 1 made of different types of thin metal wires are brought into thermal contact with each other as a temperature sensing part.