Piezoresistive pressure sensor or pressure detector assembly

• US 5,847,282 A
• Filed: 10/16/1996
• Issued: 12/08/1998
• Est. Priority Date: 02/21/1995
• Status: Expired due to Fees

• Current Assignee: Keller AG Fur Druckmesstechnik
• Original Assignee: Keller AG Fur Druckmesstechnik
• Inventors: Keller, Hans W.
• Primary Examiner(s): FELBER, JOSEPH LEON
• Application Number:
  US08/722,182
• Time in Patent Office: 783 Days
• Field of Search: 73/706, 73/727, 73/721
• US Class Current: 73/706
• CPC Class Codes: G01L 19/0645 using isolation membranes, specially adapted for protection

Abstract

An improved piezoresistive pressure sensor or an improved piezoresistive pressure pickup having a pressure measuring cell (13), a transmission diaphragm housing (7), which comprises a jacket housing section, a transmission diaphragm (17) and a backplate (21) and having a fluid pressure chamber (19) situated on the measuring diaphragm side is distinguished by the following features

the jacket housing section of the transmission diaphragm housing (7) comprises a pressure chamber sleeve (33),

the pressure chamber sleeve (33) and the backplate (21) consists of weldable steel,

the transmission diaphragm housing (7) and thus the pressure chamber sleeve (33) are or can be inserted in an annular recess (31) in the connection housing (3) in a sealing manner,

the connection housing (3) consists of a material which cannot be welded or cannot easily be welded, and

the pressure chamber sleeve (33) and the backplate (21) are permanently welded in a sealing manner so as to seal off the pressure transmission medium provided in the measuring cell inner pressure chamber (15) thus formed.

Claims

1. Piezoresistive pressure responsive sensor or pickup assembly comprising the following features:

(a) a pressure measuring cell;

(b) a transmission diaphragm housing, a pressure transmission diaphragm with opposed side surfaces mounted within said transmission diaphragm housing, and with said transmission diaphragm housing retaining the pressure measuring cell and being filled with a pressure transmission medium, and further comprising a jacket housing section and a backplate;

(c) a connection housing provided on one side of said pressure transmission diaphragm and having a fluid pressure chamber situated therein and being characterized by the following further features;

(1) the jacket housing section of the transmission diaphragm housing includes a pressure chamber sleeve;

(2) the pressure chamber sleeve and the backplate consisting of weldable steel;

(3) the transmission diaphragm housing including the pressure chamber sleeve portion of the jacket housing is adapted to be inserted in an annular recess formed in the connection housing in a sealing manner;

(4) the connection housing consisting of a workable material selected from the group consisting of brass and beryllium bronze, and wherein the pressure chamber sleeve and the backplate are permanently secured together in a sealing manner so as to seal off the pressure transmission medium filling the transmission diaphragm housing retaining the measuring cell so as to form an inner pressure chamber;

(5) the pressure measuring diaphragm being placed on a stepped shoulder formed within the connection housing so as to define the axial length of the annular recess in which the pressure chamber sleeve is received; and

(6) the pressure measuring diaphragm and the pressure chamber sleeve being joined to the annular recess portion of the connection housing through a soldered connection.

3. Piezoresistive pressure responsive sensor or pickup assembly according to claim 1, characterized in that the said extension sleeve consists of a preformed tubular material.

4. Piezoresistive pressure responsive sensor or pickup assembly according to claims 1 or 2, characterized in that the said connection housing is filled with said pressure transmission medium and retains a pressure measuring cell, and wherein said transmission diaphragm housing retaining said pressure measuring diaphragm is arranged to be sealed by means of soldering, and further in that said filling duct means in communication with the inside of the transmission diaphragm housing is provided, and wherein said filling duct means is received within said transmission diaphragm housing along a soldered joint, the filling duct consisting of a weldable material and closable by means of a closure peg consisting of a weldable material.

5. Piezoresistive pressure responsive or pickup assembly according to claim 4, characterized in that said connection housing provided with said filling duct means is a reference or differential pressure housing positioned as an axial extension to the connection housing and being fixedly connected to the latter by means of a fixing device means.

6. Piezoresistive pressure responsive sensor or pickup assembly according to claim 5, characterized in that the inside of the housing retaining said pressure measuring cell is connected by a small tube penetrating said backplate to communicate with said pressure chamber formed in said reference or differential pressure housing.

2. Piezoresistive pressure responsive sensor or pickup assembly comprising the following features:

(a) a pressure measuring cell;

(b) a transmission diaphragm housing, a pressure transmission diaphragm with opposed side surfaces mounted within said transmission diaphragm housing, and with said transmission diaphragm housing retaining the pressure measuring cell being filled with a pressure transmission medium consisting of oil, and further comprising a jacket housing section and a backplate;

(c) a connection housing provided on one side of said pressure transmission diaphragm and having a fluid pressure chamber situated on the pressure transmission diaphragm side of said transmission diaphragm housing and being characterized by the following further features;

(1) the jacket housing section of the transmission diaphragm housing includes a pressure chamber sleeve;

(2) the pressure chamber sleeve and the backplate consist of weldable steel;

(3) the transmission diaphragm housing including the pressure chamber sleeve being adapted to be sealingly inserted in an annular recess formed in the connection housing;

(4) the connection housing consisting of a workable material selected from the group consisting of brass and beryllium bronze, and wherein the pressure chamber sleeve and the backplate are permanently bonded together in a sealing manner so as to seal off the pressure transmission medium filling the transmission diaphragm housing retaining the measuring cell so as to form an inner pressure chamber;

(5) the pressure chamber sleeve being provided with an extension sleeve and wherein said transmission diaphragm is mounted adjacent said extension sleeve so as to be positioned adjacent the inner axial end of the said annular recess; and

(6) the pressure measuring diaphragm, the pressure chamber sleeve, and the extension sleeve being coupled to the inner surface of the annular recess of the connection housing through joints formed of solder.