Construction and manufacturing method for a sensor of a thermal flow measuring device

• US 8,529,127 B2
• Filed: 08/24/2010
• Issued: 09/10/2013
• Est. Priority Date: 08/24/2009
• Status: Active Grant

• Current Assignee: Endress+Hauser Flowtec AG (Endress+Hauser AG)
• Original Assignee: Endress+Hauser Flowtec AG (Endress+Hauser AG)
• Inventors: Pfau, Alex, Barth, Martin, Baur, Tobias
• Primary Examiner(s): Caputo, Lisa
• Assistant Examiner(s): WILLIAMS, JAMEL E
• Application Number:
  US12/805,904
• Publication Number:
  US 20110041598A1
• Time in Patent Office: 1,113 Days
• Field of Search: 374/208, 374/29, 732/042.2
• US Class Current: 374/208
• CPC Class Codes: G01F 1/684 Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
• CPC Class Codes: G01F 1/692 Thin-film arrangements
• CPC Class Codes: Y10T 29/49085 Thermally variable

Abstract

Thermal flow measuring device and method for the manufacture of a thermal flow measuring device with a spacer having a first cavity for accommodating a resistance thermometer, wherein the spacer has at least a first planar area, which faces the first cavity, and a second cavity, through which the resistance thermometer can be pressed by means of a hold-down onto the first planar area of the spacer.

Claims

1. A spacer for a sensor of a thermal flow measuring device, having:

hold-down means;

a first cavity for accommodating a resistance thermometer;

at least a first planar area which faces said first; and

a second cavity, through which the resistance thermometer can be pressed by means of said hold-down onto said first planar area.

2. The spacer for a sensor of a thermal flow measuring device as claimed in claim 1, wherein:

said first cavity has, at least in certain regions, an essentially rectangular cross section.

3. The spacer for a sensor of a thermal flow measuring device as claimed in claim 1, wherein:

at least said first cavity can be manufactured with a machining manufacturing method.

4. The spacer for a sensor of a thermal flow measuring device as claimed in claim 1, wherein:

said first cavity is a blind bore.

5. The spacer for a sensor of a thermal flow measuring device as claimed in claim 1, wherein:

said second cavity is approximately perpendicular to said first planar area of the spacer.

6. The spacer for a sensor of a thermal flow measuring device as claimed in claim 1, wherein:

the spacer is a body which extends along a longitudinal axis, and which has a circularly shaped cross section;

the longitudinal axis of said first cavity is approximately parallel to the longitudinal axis of the spacer;

said first planar area of the spacer is a lateral surface of said first cavity.

7. A thermal flow measuring device for determining and/or monitoring flow of a measured medium through a measuring tube, having:

a first sensor; and

a second sensor, said first sensor has a first housing secured in a sensor holder and a first resistance thermometer, and said second sensor has a second housing secured in the sensor holder and a second resistance thermometer, wherein;

at least said first resistance thermometer is embodied in such a manner that it can be heated;

said first resistance thermometer is at least partially inserted into a first cavity of a first spacer in said first housing, and said second resistance thermometer is at least partially inserted into a first cavity of a second spacer in said second housing; and

the first spacer and the second spacer have;

hold-down means;

a first cavity for accommodating a resistance thermometer;

at least a first planar area which faces said first; and

a second cavity, through which the resistance thermometer can be pressed by means of said hold-down onto said first planar area.

8. The thermal flow measuring device as claimed in claim 7, wherein:

at least said first resistance thermometer is a thin-film resistance thermometer, which has a first surface and a second surface which lies opposite the first surface; and

said first surface of said first thin-film resistance thermometer is connected with said first planar area of the first spacer.

9. The thermal flow measuring device as claimed in claim 7, wherein:

at least said first resistance thermometer is soldered onto said first planar area of the first spacer.

10. The thermal flow measuring device as claimed in claim 7, wherein:

said second surface of said first thin-film resistance thermometer is at least partially covered by thermally conductive fill material.

11. A method for manufacture of a sensor of a thermal flow measuring device, comprising the steps of:

a thin-film resistance thermometer, which has a first surface and a second surface, which lies opposite the first surface, is at least partially inserted into the first cavity of a spacer;

is soldered with its first surface onto the first planar area of the spacer; and

at least during the soldering, a hold-down is led through the second cavity of the spacer for pressing the thin-film resistance thermometer onto the first planar area of the spacer.

12. The method for manufacture of a sensor for a thermal flow measuring device as claimed in claim 11, wherein:

preformed solder portions are applied onto the resistance thermometer and/or onto the first planar area of the spacer before introduction of the resistance thermometer into the spacer.

13. The method for manufacture of a sensor for a thermal flow measuring device as claimed in claim 11, wherein:

a housing is provided which has a first open end and a second open end;

the first open end can be secured in a sensor holder, and cables for electrical contacting of the thin-film resistance thermometer lead out of the housing through the first open end of the housing; and

the spacer with the soldered-on thin-film resistance thermometer is inserted through the second open end of the housing, which is then closed with a stopper.

14. The method for manufacture of a sensor for a thermal flow measuring device as claimed in claim 11, wherein:

thermally conductive and/or thermally insulating fill material is filled into the housing and/or at least into the first cavity of the spacer, so that the thermally conductive fill material at least partially covers the second surface of the thin-film resistance thermometer.

15. The method for manufacture of a sensor for a thermal flow measuring device as claimed in claim 11, wherein:

before introduction of the spacer with the thin-film resistance thermometer into the housing, the second cavity of the spacer is at least partially filled with a solid body, which is manufactured from same material as the spacer.