Differential pressure measuring sensor with overload protection

Patent metadata

Field	Value
Publication number	US-12480829-B2
Application number	US-202118256440-A
Country	US
Kind code	B2
Filing date	Nov 26, 2021
Priority date	Dec 10, 2020
Publication date	Nov 25, 2025
Grant date	Nov 25, 2025

Abstract

A differential pressure transducer with overload protection includes a measuring element body, two separating diaphragms, two overload diaphragms with radially variable material thickness h(r), a differential pressure transducer for converting a pressure difference into an electrical signal, and two hydraulic paths. The overload diaphragms are connected to the measuring element body to form overload chambers and the separating diaphragms are connected to the measuring element body to form separating diaphragm chambers in which one of the overload diaphragms are enclosed. The separating diaphragm chambers are hydraulically connected to the overload chambers below the other separating diaphragm chamber and to the differential pressure transducer via one of the hydraulic paths, which extend at least in sections through the measuring element body. The overload diaphragms have a base surface, which faces a mating surface in an overload chamber against which the overload diaphragms are pre-stressed in the operative state at pressure equilibrium.

First claim

The invention claimed is:

1 . A differential pressure transducer with overload protection, comprising:
a measuring element body; a first separating diaphragm; a second separating diaphragm; a first overload diaphragm; a second overload diaphragm; a differential pressure transducer for converting a pressure difference into an electrical signal; a first hydraulic path; and a second hydraulic path; wherein the first overload diaphragm is connected to the measuring element body to form a first overload chamber with variable volume along a circumferential first overload diaphragm edge; wherein the second overload diaphragm is connected to the measuring element body to form a second overload chamber with variable volume along a circumferential second overload diaphragm edge; wherein the first separating diaphragm is connected to the measuring element body to form a first separating diaphragm chamber along a circumferential first separating diaphragm edge, wherein the first overload diaphragm is enclosed between the measuring element body and the first separating diaphragm; wherein the second separating diaphragm is connected to the measuring element body to form a second separating diaphragm chamber along a circumferential second separating diaphragm edge, wherein the second overload diaphragm is enclosed between the measuring element body and the second separating diaphragm; wherein the first separating diaphragm chamber is hydraulically connected to the second overload chamber via the first hydraulic path, which extends at least in sections through the measuring element body; wherein the second separating diaphragm chamber is hydraulically connected to the first overload chamber via the second hydraulic path, which extends at least in sections through the measuring element body; wherein the differential pressure transducer is hydraulically connected to the first separating diaphragm chamber and the second separating diaphragm chamber; wherein the first overload diaphragm has a first base surface, which faces a first mating surface in the first overload chamber; wherein the second overload diaphragm has a second base surface, which faces a second mating surface in the second overload chamber; wherein the first overload diaphragm is pre-stressed against the first mating surface in the operable state at pressure equilibrium, such that the first base surface rests against the first mating surface at least in sections; wherein the second overload diaphragm is pre-stressed against the second mating surface, such that the second base surface rests against the second mating surface at least in sections; wherein the first overload diaphragm has a radially variable first material thickness h(r); and wherein the second overload diaphragm has a radially variable first material thickness h(r).

2 . The differential pressure transducer according to claim 1 , wherein the first overload diaphragm has a diaphragm bed surface facing the separating diaphragm with a contour k(r) prepared by machining or forming.

3 . The differential pressure transducer according to claim 1 , wherein the material thickness h(r) of the first overload diaphragm has local extrema in a radial range 0<r<0.9 R, wherein a difference between a local maximum and a local minimum of the material thickness of the overload diaphragm is not less than two, and/or wherein an amount of a difference of a local maximum of the material thickness of the overload diaphragm and a material thickness of the overload diaphragm averaged over the radial range along the radius is not less than one material thickness.

4 . The differential pressure transducer according to claim 3 , wherein the material thickness h(r) of the overload diaphragm has not less than 4.

5 . The differential pressure transducer according to claim 1 , wherein the first overload diaphragm has a first base surface facing the first mating surface and a first diaphragm bed surface facing the first separating diaphragm, wherein the first diaphragm bed surface has a first diaphragm bed contour with an axial coordinate k(r) in order to support the first separating diaphragm in the event of a one-sided overload, wherein in the operable state at pressure equilibrium, for the second derivation of the axial coordinate k(r) of the first diaphragm bed contour according to d 2 k/dr 2 and the second derivation of the first material thickness h(r) of the first overload diaphragm according to the radius d 2 h/dr 2 , the following applies:

∫

0

ℊ
·
R

d
2

⁢

k
⁡
(
r
)

dr
2

·

d
2

⁢

h
⁡
(
r
)

dr
2

⁢
dr

∫

0

ℊ
·
R

(

d
2

⁢

h
⁡
(
r
)

dr
2

)

2

⁢
dr

=
T

where g is a factor defining a bound for the integration, where 0.9≤g≤1, where T is a dimensionless characteristic number that is not less than 0.9.

Assignees

• Endress Hauser Se Co Kg

Inventors

• Uehlin Thomas
• Getman Igor
• Mack Benjamin

Classifications

• G01L13/026

  involving double diaphragm · CPC title

• G01L19/0645

  using isolation membranes, specially adapted for protection · CPC title

• G01L13/025

  using diaphragms · CPC title

• G01L19/0618 Primary

  Overload protection · CPC title