JPH0458569B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a small-sized blackbody furnace used for the calibration of objects having a large measurement angle, such as microscope radiation thermometers.

[Prior Art] In recent years, radiation thermometers have been used to non-contactly measure the temperature of minute parts. It is also desired that the comparison blackbody furnace used for calibration be small and have a minute opening.

Conventionally, as shown in FIG. 1, a heating element (heater) 2 was wrapped around the outer periphery of a radiator (heat-resistant block) 1 having a recessed portion 1a for heating.

[Problems to be Solved by the Invention] However, with such a configuration, the diameter in the outer circumferential direction becomes large, making it impossible to achieve miniaturization, creating a temperature distribution in the recess 1a, making it impossible to achieve high precision, and making it difficult to improve the accuracy of the recess 1a. When inspected with a radiation thermometer, it was found that there was a defect in which unnecessary radiant energy was incident from the surface of the heating element 2 as stray light, causing a calibration error.

In view of the above points, an object of the present invention is to provide a blackbody furnace that is smaller and more precise by providing a heating element behind a heat-resistant block.

[Means for Solving the Problems] The present invention includes a heat-resistant block having a recess, a thermometer inserted into the back surface of the heat-resistant block, and a heat-resistant block provided on the back surface of the heat-resistant block with the thermometer inserted inside and outside the heat-resistant block. a heating tube with a heating element wrapped around it;
a heat-equalizing tube joined to the heat-resistant block and surrounding the heat-generating tube with a gap therebetween except for at least the recessed portion;
This blackbody furnace includes a heat insulating section provided around the outer periphery of the soaking tube.

[Embodiment] FIGS. 2a and 2b are an explanatory front view and a partially sectional side view showing an embodiment of the present invention, and the same reference numerals as in FIG. 1 indicate the same components.

In the figure, 1 is a radiator (heat-resistant block) made of a material with high emissivity and excellent thermal conductivity, such as graphite or silicon carbide.
mm, and has a recess 1a with a depth of several mm, and a hole is provided on the back surface into which a thermometer 4, such as a sheathed thermocouple, is inserted to measure the temperature of the recess 1a. A heating tube 5 made of alumina or the like with an outer diameter of about 2 mm is connected to the back surface of the radiator 1, and a heating element (heater) 2 is non-inductively wound around it, and a thermometer 4 is inserted inside. A soaking tube 6 made of A1, a heat pipe, etc., which has excellent heat conductivity, is fitted into the tube. This soaking tube 6 is
The part that contacts the opening of the radiator 1 is formed into a conical shape 6a, and an opening with a diameter of 1 mm is provided in the center, and is spaced apart from the heat generating tube 5. 7
is a heat insulating part that insulates the heat soaking tube 6, and is made of a material with low thermal conductivity such as stainless steel.

In other words, the heat generated by the heating element 2 is transferred to the heating tube 5.
The back of the radiator 1 is directly heated by heat conduction, and the heat irradiated by cavity radiation in the space with the soaking tube 6 is heated from the periphery of the radiator 1 via the soaking tube 6. As a result, the radiator 1 is uniformly heated, has no temperature difference with the thermometer 4, and serves as a reference radiation source that can be precisely calibrated.

Moreover, the outer diameter of the heat insulating part 7 is approximately 14 mm, and its surface emissivity is kept below 0.5, so stray light components emitted from surfaces 6a and 7a other than the apertures are absorbed when the diameter of the lens of the radiation thermometer is 100 mm or more. In some cases, it is less than 1%. As shown in FIG. 3, the present invention is extremely effective in calibrating a device having a large measurement angle θ, such as a microscope-type radiation thermometer 3 comprising a lens L, a detection element D, an amplifier A, an indicator 1, etc. Note that the blackbody furnace is illustrated in a simplified manner by showing only the outer shape of the heat insulating section 7. Further, the lens L may be of Cassegrain type.

[Effects of the Invention] As described above, the present invention includes a radiator (heat-resistant block) having a small concave portion, a heating element provided at the rear of the heat-resistant block, a heat equalizing tube provided to surround the radiator, etc. This is a blackbody furnace.

Since the heating element is installed behind the heat-resistant block, it does not increase in the outer diameter direction and the cross section can be made smaller.The heat-resistant block and heating element are surrounded by a heat equalizing tube, so the temperature inside is uniform. Therefore, the temperature difference between the recess and the thermometer is small, making it possible to realize an ultra-compact blackbody furnace with extremely high precision.

[Brief explanation of drawings]

FIG. 1 is a configuration explanatory diagram showing a conventional example, FIG.
FIG. 3 is a configuration explanatory diagram showing an embodiment of the present invention. 1... radiator (heat resistant block), 1a... recess,
2... Heating element, 3... Radiation thermometer, 4... Thermometer, 5... Heat generating tube, 6... Soaking tube, 7... Heat insulating section.

Claims (1)

[Claims] 1. A heat-resistant block having a recess, a thermometer inserted into the back surface of the heat-resistant block, a heat-generating tube provided on the back surface of the heat-resistant block, into which the thermometer is inserted, and a heating element wrapped around the outside; A blackbody furnace comprising: a heat soaking tube connected to a heat-resistant block and surrounding the heat generating tube with a gap therebetween, excluding at least the recessed portion; and a heat insulating section provided around the outer periphery of the heat soaking tube.