Pressure measuring device and method for producing same

Patent metadata

Field	Value
Publication number	US-2021237195-A1
Application number	US-201917251407-A
Country	US
Kind code	A1
Filing date	May 23, 2019
Priority date	Jun 14, 2018
Publication date	Aug 5, 2021
Grant date	—

Abstract

A pressure measuring device includes a ceramic pressure sensor including a ceramic measuring membrane and a sensor mounting configured to secure the pressure sensor such that a membrane region of the measuring membrane surrounded by a membrane edge is contactable with a medium having a pressure to be measured. The sensor mounting includes a titanium or titanium alloy mounting element including an opening through which the membrane region is contactable with the medium. The membrane edge is connected directly with the mounting element by a diffusion weld produced by a diffusion welding method.

First claim

1 - 14 . (canceled)

15 . A pressure measuring device, comprising:
a pressure sensor including a ceramic measuring membrane, the measuring membrane comprising a membrane region surrounded peripherally on all sides by a membrane edge; and a sensor mounting configured to secure the pressure sensor such that the membrane region of the measuring membrane is contactable with a medium having a pressure to be measured, wherein the sensor mounting comprises a titanium or titanium alloy mounting element that includes an opening through which the membrane region is contactable with the medium, wherein the membrane edge of the measuring membrane is connected directly with the mounting element by a diffusion weld, wherein the diffusion weld is produced by a diffusion welding method by which the measuring membrane becomes joined to the mounting element.

16 . The pressure measuring device of claim 15 , wherein the pressure sensor includes at least one sensor component disposed on a side of the measuring membrane facing away from the diffusion weld.

17 . The pressure measuring device of claim 15 , wherein the pressure sensor is a freestanding component secured solely by the diffusion weld.

18 . The pressure measuring device of claim 15 , wherein the sensor mounting includes a sensor support disposed on a rear side of the pressure sensor facing away for the diffusion weld, the sensor support configured as to support the pressure sensor on the rear side by which support a pressure resistance of the sensor mounting is increased for pressure loads exerted through the opening on the pressure sensor.

19 . The pressure measuring device of claim 15 , wherein the measuring membrane comprises a polycrystalline ceramic, a polycrystalline oxide ceramic or polycrystalline aluminum oxide (Al 2 O 3 ), has a surface roughness of greater than or equal to 0.1 μm, has a membrane thickness of 0.05 mm to 3 mm, and/or has a membrane diameter of greater than or equal to 17 mm, and/or
wherein the mounting element comprises titanium or a titanium alloy, wherein the titanium alloy has a coefficient of thermal expansion matched to a coefficient of thermal expansion of the ceramic of the measuring membrane and/or a modulus of elasticity of 100 GPa to 120 GPa.

20 . The pressure measuring device of claim 15 , wherein the mounting element includes a recess bounded on all sides by a wall region as to surround the pressure sensor peripherally and spaced from the pressure sensor, and the mounting element includes a radially inwardly extending shoulder, which adjoins the wall region at an end thereof, and surrounds the opening of the mounting element,
wherein the membrane edge of the measuring membrane is connected by the diffusion weld to an inner surface of the shoulder such that the membrane edge is spaced from the wall region.

21 . The pressure measuring device of claim 15 , further comprising a process connection integrated with the mounting element or a process connection configured as a separate component of the mounting element and connected with the mounting element, wherein the process connection is configured to enable the pressure measuring device to be mounted to a complementary connection and/or to be mounted to a complementary differential pressure line connection complementary.

22 . The pressure measuring device of claim 21 , wherein the process connection is connected with the mounting element by a weld.

23 . The pressure measuring device of claim 15 , wherein the pressure sensor includes an electromechanical transducer configured to convert a deflection of the measuring membrane dependent on the pressure to be measured acting on the measuring membrane into an electrical variable, based on which the pressure to be measured is determined using a measuring electronics connected or connectable to the transducer.

24 . The pressure measuring device of claim 15 , wherein the pressure sensor includes a base body connected with the measuring membrane by a joint such that a pressure chamber is as to defined and enclosed within the pressure sensor.

25 . A method for manufacturing a pressure measuring device, the method comprising:
fabricating the measuring membrane and the mounting element or at least a portion of the mounting element to be connected with the measuring membrane as separate parts; connecting the measuring membrane to the mounting element or to the portion of the mounting element using a diffusion welding process to form a diffusion weld therebetween, wherein the membrane edge of the measuring membrane is connected to a region of the mounting element such that:
an arrangement is produced in which the membrane edge and the region of the mounting element seat directly against each other; and
the membrane edge and the region of the mounting element are pressed against each other under vacuum or under a protective gas atmosphere by a compressive pressure and, under the compressive pressure acting thereon, are subjected to a heating process in which the arrangement is heated to a temperature at which a diffusion process effecting the diffusion weld occurs.

26 . The method of claim 25 , wherein, during the diffusion welding operation, the arrangement is kept over a time period from 60 minutes to 120 minutes under the compressive pressure, which is 1 MPa to 10 MPa, at a temperature in a range from 1000° C. to 1400° C.

27 . The method of claim 25 , wherein, following the diffusion welding operation, the pressure sensor is completed by arranging at least one sensor component on a side of the measuring membrane facing away from the diffusion weld.

28 . The method of claim 27 , further comprising, after performing the diffusion welding operation:
placing a base body on the measuring membrane such that a pressure chamber is defined and enclosed within the pressure sensor, wherein a joint material is disposed between the base body and the measuring membrane; and subsequently, joining the base body and the measuring membrane via the joint material, whereby a joint is produced therebetween.

29 . The method of claim 28 , wherein the pressure sensor comprises a capacitive, electromechanical transducer, which includes a measuring electrode disposed on a membrane facing, front face of the base body and a counter electrode disposed on a base body facing, inner face of the measuring membrane, wherein the method comprises applying the counter electrode on the measuring membrane before the measuring membrane and base body are joined, and
wherein the base body includes the measuring electrode and components to enable an electrical connection of the transducer to a measuring electronics before the base body and the measuring membrane are joined.

Assignees

• Endress Hauser Se Co Kg

Inventors

• Rossberg Andreas
• Tham Anh Tuan
• Schmidt Elke
• Ponath Nils
• Conradt Jonas
• Wang Yanli
• Uehlin Thomas

Classifications

• G01L19/147

  Details about the mounting of the sensor to support or covering means · CPC title

• G01L13/025

  using diaphragms · CPC title

• G01L9/0075 Primary

  using a ceramic diaphragm, e.g. alumina, fused quartz, glass · CPC title

• C04B2237/403

  Refractory metals · CPC title

• C04B2237/343

  Alumina or aluminates · CPC title