Pressure difference sensor for providing a pressure measurement signal

Patent metadata

Field	Value
Publication number	US-10458874-B2
Application number	US-201715652341-A
Country	US
Kind code	B2
Filing date	Jul 18, 2017
Priority date	Jul 29, 2016
Publication date	Oct 29, 2019
Grant date	Oct 29, 2019

Abstract

A pressure difference sensor for providing a pressure measurement signal, comprising: a pressure difference measuring cell, which is suppliable with first and second pressures and which outputs the pressure measurement signal; first and second ceramic stiffening elements, each of which is joined with the pressure difference measuring cell and has a duct, via which the first, respectively the second, pressure is suppliable to the pressure difference measuring cell; a platform with first and second pressure input openings, each of which extends from a first surface to a second surface of the platform, wherein the pressure input openings are sealed on the first surface, each with its own isolating diaphragm, and first and second pressures tubes, which are arranged between the stiffening elements and the platform, and wherein each of the first pressure tube and the second pressure tube has at least one bend in a region between the platform and a first, respectively second, connecting area of the corresponding pressure tube.

First claim

The invention claimed is:

1. A pressure difference sensor for providing a pressure measurement signal, comprising:
a pressure difference measuring cell, which is suppliable with first and second pressures and which has a transducer, which outputs the pressure measurement signal as a function of a difference between the first and second pressures;
a first ceramic stiffening element, which is joined with said pressure difference measuring cell and which has a first duct, via which the first pressure is suppliable to said pressure difference measuring cell;
a second ceramic stiffening element, which is joined with said pressure difference measuring cell and which has a second duct, via which the second pressure is suppliable to said pressure difference measuring cell;
a platform with first and second pressure input openings, each of which extends from a first surface to a second surface of said platform, wherein said pressure input openings are sealed on the first surface, each with its own isolating diaphragm;
a first pressure tube, which with a first end communicates with said first pressure input opening and which is pressure tightly connected with said platform, wherein said first pressure tube with a second end is pressure tightly connected with said first stiffening element at a first connecting area; and
a second pressure tube, which with a first end communicates with said second pressure input opening and which is pressure tightly connected with said platform, wherein said second pressure tube with a second end is pressure tightly connected with said second stiffening element at a second connecting area, wherein:
said first pressure tube has at least one bend in a region between the second surface of said platform and the first connecting area of the corresponding pressure tube; and
said second pressure tube has at least one bend in a region between the second surface of said platform and the second connecting area of the corresponding pressure tube.

2. The pressure difference sensor as claimed in claim 1 , wherein:
said at least one bend in said pressure tubes is embodied in such a manner that a thermomechanical reaction of said platform on a composite of said stiffening elements and said pressure difference measuring cell is minimized at thermal equilibrium.

3. The pressure difference sensor as claimed in claim 1 , wherein:
said at least one bend of a pressure tube is embodied in such a manner that said first and second pressure tubes are directed toward one another, preferably cross over one another, and essentially the following holds:



d
·

α
P

+

c
·

α
SE

·

+

a
2

·

α
DC

-

(

c
+
d
+

a
2

)

·

α
PT

d
·

α
P

+

c
·

α
SE

·

+

a
2

·

α
DC

+

(

c
+
d
+

a
2

)

·

α
PT



≤
β

wherein the following definitions hold:
a: thickness of said pressure difference measuring cell in the direction of a first axis, which is defined by a first midpoint of said first connecting area and a second midpoint of said second connecting area;
c: separation in the direction of said first axis between a second axis, which represents a symmetry axis of the pressure difference sensor, and said first midpoint;
d: separation in the direction of said first axis between said second axis and a midpoint of the first end of the pressure tube;
α DC : thermal expansion coefficient of said pressure difference measuring cell;
α SE : thermal expansion coefficient of said stiffening elements;
α PT : thermal expansion coefficient of the pressure tubes;
α P : thermal expansion coefficient of said platform; and
β≤0.1, preferably ≤0.05, especially preferably ≤0.02.

4. The pressure difference sensor as claimed in claim 1 , wherein:
said at least one bend of a pressure tube is embodied in such a manner that said first and second pressure tubes are directed away from one another and essentially the following holds:



(

d
-
c
-

a
2

)

·

α
PT

+

c
·

α
SE

+

a
2

Assignees

• Endress Hauser Gmbh Co Kg
• Endress Hauser Se Co Kg

Inventors

• Kober Timo
• Lemke Benjamin
• Teipen Rafael
• Mack Benjamin

Classifications

• G01L19/0618

  Overload protection · CPC title

• G01L13/00

  Devices or apparatus for measuring differences of two or more fluid pressure values · CPC title

• G01L19/04 Primary

  Means for compensating for effects of changes of temperature {, i.e. other than electric compensation} · CPC title

• G01L19/0681

  Protection against excessive heat · CPC title

• G01L13/025

  using diaphragms · CPC title