Differential pressure sensor for determining the differential pressure between two pressures

Patent metadata

Field	Value
Publication number	US-12399076-B2
Application number	US-202017908646-A
Country	US
Kind code	B2
Filing date	Dec 16, 2020
Priority date	Dec 20, 2019
Publication date	Aug 26, 2025
Grant date	Aug 26, 2025

Abstract

A differential pressure sensor for determining the differential pressure between two pressures includes a converter chamber including a differential pressure measuring cell, and a measuring unit including a main body and a coplanar double-membrane system with two double membranes, each including a separating membrane and an overload membrane with a pressure chamber between the separating membrane and the overload membrane and an additional pressure chamber between the overload membrane and the main body. Each pressure chamber and each additional pressure chamber is paired with at least one capillary connection such that in the event of an overpressure, the overpressure is hydraulically transmitted from the high-pressure side to the low-pressure side via a hydraulic fluid such that the overload membrane and the separating membrane are deflected, and the hydraulic fluid displaced from the high-pressure side to the additional pressure chamber on the low-pressure side before the overpressure reaches the pressure-sensitive element.

First claim

The invention claimed is:

1. A differential pressure sensor for determining the differential pressure between two pressures in a process, the sensor comprising:
a converter chamber including a differential pressure measuring cell including a pressure-sensitive element disposed in the converter chamber; and
a measuring unit comprising:
a base body including an end portion configured to face the process; and
a coplanar double-membrane system disposed in the end portion of the base body and including a first double membrane and a second double membrane,
wherein each double membrane comprising a separating membrane and an overload membrane arranged behind the separating membrane relative to a direction of action of pressure from the process,
wherein a first pressure chamber is defined between a first separating membrane and a first overload membrane of the first double membrane, and a first additional pressure chamber is defined between the first overload membrane and the base body of the measuring unit,
wherein a second pressure chamber is defined between a second separating membrane and a second overload membrane of the second double membrane, and a second additional pressure chamber is defined between the second overload membrane and the base body of the measuring unit,
wherein each of the first and second pressure chambers is connected to a corresponding capillary connection, and each of the first and second additional pressure chambers is connected to at least one further capillary connection,
wherein each capillary connection is configured and coupled such that pressures present at the first and second separating membranes are hydraulically transmitted to the pressure-sensitive element during normal measuring operation and such that,
when an overpressure is present at the first separating membrane or second separating membrane, thereby defining a high-pressure side and a low-pressure side, respectively, the overpressure is hydraulically transmitted from the high-pressure side to the low-pressure side via a hydraulic fluid such that the first or second overload membrane and the first or second separating membrane corresponding to the low-pressure side are deflected, and hydraulic fluid displaced from the high-pressure side is received in the respective first or second additional pressure chamber of the low-pressure side before the overpressure acts upon the pressure-sensitive element,
wherein the base body of the measuring unit is configured as a single piece and has a substantially fully symmetrical construction, at least relative to the coupling of the capillary connections, with respect to a plane extending centrally and perpendicularly between the first double membrane and the second double membrane of the coplanar double-membrane system,
wherein the first and second overload membranes are preloaded such that each bears against the base body of the measuring unit in a substantially form-fitting manner during normal measuring operation and such that, only when an overpressure endangering the pressure-sensitive element is exceeded, the first overload membrane corresponding to the low-pressure side is lifted off the base body due to the overpressure, while the second overload membrane on the high-pressure side is pressed against the base body.

2. The sensor of claim 1 , wherein the measuring unit is an integral component of a substantially symmetrically constructed process connection, and wherein the converter chamber is integrated in a housing adapter connected to the process connection.

3. The sensor of claim 1 , wherein the capillary connections are configured as capillary bores and/or as capillary tubes.

4. The sensor of claim 1 , wherein a number, arrangement and coupling of the capillary connections is configured such that the pressure-sensitive element and the first and second overload membranes configured for overpressure protection are connected hydraulically in series.

5. The sensor of claim 1 , wherein a number, arrangement and coupling of the capillary connections is configured such that the pressure-sensitive element and the first and second overload membranes configured for overpressure protection are connected hydraulically in parallel such that a same pressure acts on the pressure-sensitive element and the first and second overload membranes.

6. The sensor of claim 1 , wherein coupling of the connecting capillaries to enable overpressure protection is provided in the measuring unit.

7. The sensor of claim 1 , wherein coupling of the connecting capillaries to enable overpressure protection is provided in an intermediate region of the measuring unit and the converter chamber, or partially in the intermediate region of the measuring unit and the converter chamber and partially in the converter chamber.

8. The sensor of claim 1 , wherein coupling of the connecting capillaries to enable overpressure protection is provided in the converter chamber or in a rear region of the converter chamber.

Assignees

• Endress Hauser Se Co Kg

Inventors

• Uehlin Thomas
• Gutmann Florian
• Beck Alexander
• Getman Igor
• Mack Benjamin
• Noack Michael
• Hügel Michael

Classifications

• G01L13/026

  involving double diaphragm · CPC title

• G01L19/141

  Monolithic housings, e.g. molded or one-piece housings · CPC title

• G01L13/06

  using electric or magnetic pressure-sensitive elements · CPC title

• G01L19/0618 Primary

  Overload protection · CPC title

• G01L19/0046 Primary

  using isolation membranes (G01L13/026 and G01L19/0645 take precedence) · CPC title