BLOCK CALIBRATOR FOR CALIBRATING A TEMPERATURE SENSOR

Abstract

A block calibrator for calibrating a temperature sensor with a heating block, on which or in which at least one heating appliance is disposed, and wherein the heating block features a receiving bore for receiving a calibration insert, into which a test object formed by a temperature sensor can be inserted. According to the invention, an air gap (L) is formed at least in certain areas between an internal wall of the receiving bore and an external wall of the calibration insert.

Claims

1.-15. (canceled)

16. A block calibrator for calibrating a temperature sensor, comprising: a heating block including a receiving bore, the receiving bore having an internal wall; at least one heating appliance disposed on or in the heating block; a calibration insert received by the receiving bore of the heating block, the calibration insert having an external wall, the calibration insert adapted for insertion of at least one test object therein, the test object including a temperature sensor; and wherein an air gap is formed at least in certain areas between the internal wall of the receiving bore and the external wall of the calibration insert.

17. The block calibrator according to claim 16, further comprising at least one centring element for the centring of the calibration insert in the receiving bore.

18. The block calibrator according to claim 17, wherein the centering element completely surrounds the calibration insert at a placement position.

19. The block calibrator according to claim 17, wherein the centring element is disposed so that it holds onto the receiving bore and/or onto the calibration insert.

20. The block calibrator according to claim 17, wherein the calibration insert includes a circumferential groove in the external wall, the centering element being disposed in the circumferential groove.

21. The block calibrator according to claim 20, wherein the centering element comprises an O-ring.

22. The block calibrator according to claim 20, wherein the centering element comprises a metallic spring element.

23. The block calibrator according to claim 22, wherein the spring element is inserted in the groove.

24. The block calibrator according to claim 22, wherein the spring element is a coil spring, wherein the windings of the coil spring are configured to protrude with a section of a circumference extending out of the external wall of the calibration insert, bridging the air gap, and being supported by the internal wall of the receiving bore.

25. The block calibrator according to claim 16, wherein the air gap has gap dimensions that are greater than a clearance fit of the calibration insert in the receiving bore according to DIN 7157 and/or the air gap has gap dimensions that are greater than 0.5 mm-2.5 mm.

26. The block calibrator according to claim 16, wherein the external wall of the calibration insert is formed so that it deviates, in sections, from a cylindrical lateral surface.

27. The block calibrator according to claim 26, wherein a section is formed with a reduced diameter in the external wall along a longitudinal axis of the calibration insert.

28. The block calibrator according to claim 26, wherein the calibration insert includes first circumferential segments with a smaller diameter and second circumferential segments with a greater diameter.

29. A calibration insert for a block calibrator according to claim 16, the calibration insert comprising: a centering element, by means of which the calibration insert is disposed in a centred manner in the receiving bore of the heating block.

30. The calibration insert according to claim 29, wherein first circumferential segments with a smaller radius and second circumferential segments with a greater radius are formed in the external wall.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In the following, other measures improving the invention are described in more detail in conjunction with the description of a preferred exemplary embodiment of the invention, based on the figures. In the drawings:

[0019] FIG. 1 shows a schematic cross-sectional view of a block calibrator,

[0020] FIG. 2 shows an exemplary embodiment of a calibration insert with a centring means according to the invention,

[0021] FIG. 3 shows the calibration insert with a section in the external wall having a reduced diameter,

[0022] FIG. 4 shows a schematic top view of the block calibrator with a uniformly circumferential smaller air gap,

[0023] FIG. 5 shows the top view of the block calibrator according to FIG. 4 with a greater air gap,

[0024] FIG. 6. shows the top view of the block calibrator with a calibration insert, which comprises circumferential segments with different diameters and

[0025] FIG. 7 shows a diagram of the temperature along a circumferential segment of 90 of the cylindrical calibration insert with different temperature profiles.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] FIG. 1 shows a schematic view of a cross-section of the block calibrator 1. The block calibrator has a heating block 10 as a base body, and a receiving bore 12, into which a calibration insert 13 can be introduced, is formed in the heating block 10. The receiving bore 12 is not necessarily produced using a drilling process, so that the receiving bore 12 can be introduced into the heating block 10 in any conceivable manner. The exemplary embodiment shows the calibration insert 13 in a rotationally symmetrical shape, which extends around a longitudinal axis 20, the cross-sectional shape of the receiving bore 12 in the shown exemplary embodiment being adapted to a circular cross-sectional shape of the calibration insert 13. A sensor bore 21, which extends concentrically with the longitudinal axis 20 and into which a test object 14 in form of a temperature sensor can be introduced, is formed within the calibration insert 13. The figure exemplarily only shows one sensor bore 21, but it also possible to form several sensor bores 21 in only one calibration insert 13.

[0027] Two heating appliances 11, which can be formed by Peltier elements, are exemplarily attached on the outside of the heating block 10. The heating appliances 11 make it possible to heat the heating block 10, wherein it is also conceivable to cool the heating block 10 with the heating appliances 11, in particular when the heating appliances 11 are formed as Peltier elements.

[0028] An additional blind hole, into which a reference sensor 22 is inserted, is provided on the bottom side in the heating block 10. The reference sensor 22 allows for determining a temperature of the heating block 10.

[0029] The calibration insert 13 is interchangeably inserted in the heating block 10. To this end, the receiving bore 12 is formed so that it is open toward the upper side of the heating bock 10, so that the receiving bore 12 forms another blind hole in the heating block 10. The test object 14 can also be introduced into and removed from the calibration insert 13 on the upper side. The calibration insert 13 serves amongst others for receiving various test objects 14 that have different diameters. In addition, it is possible to choose a calibration insert 13 adapted to a test object 14 and to insert it into the receiving bore 12.

[0030] As a main feature of the block calibrator 1 according to the invention, an air gap L is formed between an internal wall 15 of the receiving bore 12 and an external wall 16 of the calibration insert 13. The exemplary embodiment shows a constant air gap L along the circumferential surface of the calibration insert 13 with a gap dimension of e.g. 0.5 mm-2.5 mm. Due to the provided air gap L, a heat input from the heating block 10 into the calibration insert 13 occurs via the air gap L, resulting in a homogenization of the temperature in the calibration insert 13. By avoiding a solid contact at least between the lateral surface of the calibration insert 13 and the heating block 10, no areas with an increased heat input are formed, and a homogenization of the heat in each circumferential segment around the longitudinal axis 20 can be obtained in the calibration insert 13, due to the thermal conductivity of the material of the calibration insert 13, without being significantly influenced by the heating block 10. In order to minimize the solid contact of the insert bottom 23 with the bottom side of the receiving bore 12 in the heating block 10, the calibration insert 13 has a recess 24 at its bottom surface. As a result, there remains only an external ring contact of the insert bottom 23 with the bottom of the receiving bore 12 in the heating block 10.

[0031] In order to achieve a centring of the calibration insert 13 in the receiving bore 12, the arrangement of the calibration insert 13 in the heating block features a centring means 17. The centring means 17 is exemplarily designed as a spring element 19 in the form of a coil spring, which is inserted into a circumferential groove 18, wherein the groove 18 is introduced into the upper area of the lateral surface of the calibration insert 13. Although not shown here, it is also possible to introduce another centring means 17 into the lateral surface of the calibration insert 13, for example close to the insert bottom 23. It is more specifically advantageous to dispose another centring means 17 in the internal wall 15 of the receiving bore 12 in the bottom area of the blind bore.

[0032] The centring means 17 causes a concentric arrangement of the calibration insert 13 in the receiving bore 12, so that the central axis of the receiving bore 12 and the longitudinal axis 20 of the calibration insert 13 coincide.

[0033] FIG. 2 shows an example of the calibration insert 13 with a centring means 17 in the form of a spring element 18, which is introduced into the circumferential groove 18 in the lateral surface of the calibration insert 13. The centring means 17 is located at the upper end of the calibration insert 13 adjacent to the front surface, in which only one sensor bore 21, for example, is formed for inserting the test object 14.

[0034] FIG. 3 shows an exemplary embodiment of the calibration insert 13 with the centring means 17 in the form of a spring element 19 in the upper area of the calibration insert 13 adjacent to the front surface in which the sensor bore 21 is formed.

[0035] A section A with a reduced diameter, which points toward the insert bottom 23, extends in the external wall 16 along the longitudinal axis 20 in the external circumferential surface of the calibration insert 13. Due to the accompanying enlargement of the air gap L shown in FIG. 1, the heat input into section A from the heating block 10 into the calibration insert 13 is further weakened. This way, a desired temperature profile can be imparted in the calibration insert 13 along the longitudinal axis 20, in particular for homogenizing the temperature along the length of the longitudinal axis 20.

[0036] FIGS. 4, 5 and 6 respectively show, in accordance with the sectional view I-I in FIG. 1, a top view onto the block calibration 1 with the heating block 10, with the heating elements 11 in a lateral arrangement on the heating block 10 and with the receiving bore 12, which is centrically provided in the heating block 10. The heating block 10 has a rectangular cross-section.

[0037] The calibration insert 13 is introduced into the receiving bore 12 and the air gap L is circumferentially located between the calibration insert 13 and the receiving bore 12. FIG. 4 shows a small air gap L, for example with a gap size of 0.5 mm. FIG. 5 shows the air gap L with a gap size of e.g. 2.5 mm.

[0038] FIG. 6 shows a calibration insert 13 with a shape that differs from a cylindrical shape. The calibration insert 13 therefore has first circumferential segments U1 with a greater diameter, and the calibration insert 13 has second circumferential segments U2 with a smaller diameter.

[0039] The first circumferential segments U1 result in a smaller gap size of e.g. only 0.5 mm, and the second circumferential segments U2, with the smaller diameter of the calibration insert 13, result in a greater gap size of the air gap L of e.g. 2.5 mm.

[0040] This configuration of the calibration insert causes a lower heat transfer into the lateral areas of the second circumferential segments U2, which correspond to those areas in which the heating means 11 are disposed outside on the heating block 10. The resulting inhomogeneous temperature profile in the heating block 10 and bigger and smaller air gaps L lead to a fully balanced temperature profile in the calibration insert 13.

[0041] FIG. 7 shows a diagram of a progression of the temperature T along an angle of 0-90 representing a segment of the calibration insert 13 which corresponds to a quarter of the cross-section surface, the heating elements 11 being disposed at the angle of 0 and the angle of 90 depicting the edge of the segment that is perpendicular to the arrangement of the heating elements 11.

[0042] With respect to FIG. 6, the air gap is very big at an angle of 0, and the air gap is small at an angle of 90. The angle of 0 thus corresponds to the second circumferential segment U2, and the angle of 90 corresponds to the first circumferential segment U2 in FIG. 6.

[0043] The continuous graph represents the temperature changing along the angle of 0-90, which, according to FIG. 4, occurs when a small air gap L is formed between the receiving bore 12 and the calibration insert 13 along the entire circumference. The dashed graph shows the temperature profile along the 90 segment according to FIG. 5, in which the air gap L already has a bigger size. The dot-dashed line represents the temperature profile in the calibration insert 13 along a 90 segment with the circumferential segments U1 and U2 in the calibration insert 13. The temperature progressions show that by enlarging the air gap, a homogenization of the temperature in the calibration insert 13 can be produced, and if the circumferential segments U1 and U2 with corresponding radiuses in the calibration insert 13 are adapted in such a manner that a weaker heat transition into hotter areas of the heating block 10 is caused, the temperature profile in the calibration insert 13 can be substantially completely homogenized.

[0044] The implementation of the invention is not limited to the previously mentioned exemplary embodiment. Rather, a number of variants are conceivable, which make use of the described solution in fundamentally different embodiments. All the features and/or advantages resulting from the claims, the description and the drawings, including design details or spatial arrangements, can be essential to the invention both on their own and in various combinations.

LIST OF REFERENCE NUMERALS

[0045] 1 Block calibrator [0046] 10 Heating block [0047] 11 Heating appliance [0048] 12 Receiving bore [0049] 13 Calibration insert [0050] 14 Test object [0051] 15 Internal wall [0052] 16 External wall [0053] 17 Centring means [0054] 18 Circumferential groove [0055] 19 Spring element [0056] 20 Longitudinal axis [0057] 21 Sensor bore [0058] 22 Reference sensor [0059] 23 Insert bottom [0060] 24 Recess [0061] L Air gap [0062] A Section with a reduced diameter [0063] U1 First circumferential segment [0064] U2 Second circumferential segment