Measuring and testing – Fluid pressure gauge – Diaphragm
Reexamination Certificate
2000-01-12
2001-09-11
Fuller, Benjamin R. (Department: 2855)
Measuring and testing
Fluid pressure gauge
Diaphragm
C073S715000
Reexamination Certificate
active
06286372
ABSTRACT:
BACKGROUND OF THE INFORMATION
European Patent No. 0 164 413 describes a pressure differential measuring transducer having a membrane disk designed as a membrane wafer made of silicon. Two side by side measuring membranes side by side are formed by thinning (via etching) the membrane wafer in the area of the two measuring membranes. The two measuring membranes are in contact with a common fluid space formed by a recess in another wafer fixedly connected to the membrane wafer. On the side of the measuring membranes facing away from the common fluid space, they are acted upon by a first pressure and a second pressure, so that the deflection of each of the two measuring membranes indicates the pressure difference.
SUMMARY
An object of the present invention is to provide a pressure differential measuring transducer, where the zero point and sensitivity are almost completely independent of changes in static pressure.
To achieve this object, a pressure differential measuring transducer is provided having a first measuring membrane which is on a surface of a membrane disk and can be acted upon by a first pressure on its one side, and having a second measuring membrane next to the first measuring membrane which can be acted upon by a second pressure on its one side and having a common tight fluid space bordering on the other sides of the measuring membranes. The first pressure can be supplied to the open end of a tube which is closed at its other end. A part of the membrane disk carrying the first measuring membrane penetrates through the interior of the tube between its two ends with a seal and its dimensions are such that the first pressure can act on both sides of the membrane disk in the interior of the tube. Another part of the membrane disk having the second measuring membrane extends in an interior space of a container adjacent to the tube to which the second pressure can be supplied, so that it can be acted upon by the second pressure on both sides.
An advantage of the pressure differential measuring transducer according to the present invention is that the part of the membrane disk carrying the first membrane is exposed to the one pressure on both sides, so that there can be no “breathing” of this part of the membrane disk when there are changes in static pressure. The same thing is also true regarding the second part of the membrane disk because this part is also exposed to the second pressure on all sides. Thus, there is no change in volume of the membrane disk on the whole when there is a change in static pressure with the pressure differential measuring transducer according to the present invention, so that the initial tension of the two measuring membranes does not change. Therefore, the zero point and sensitivity are independent of the static pressure, which has a very advantageous effect on the measurement accuracy of the pressure differential measuring transducer according to the present invention.
With the pressure differential measuring transducer according to the present invention, the membrane disk may be made of different materials. With regard to the simplest possible production and the smallest possible design of the measuring transducer, it is especially advantageous if the membrane disk is made of silicon and the tube is made of a material with a thermal expansion coefficient similar to that of silicon.
For sealed mounting of the membrane disk in the tube, it is advantageous if the one part of the membrane disk is mounted on the tube with a seal provided by solder or an adhesive. The adhesive may advantageously contain ceramic beads; then there is the possibility of keeping the distance between the membrane disk and the transverse slit in the tube as uniform as possible throughout.
There are various options with regard to accommodation of the tube provided with the membrane disk in an overall structure of the pressure differential measuring transducer according to the present invention. It is especially advantageous if the tube is mounted with its open end in the area of an opening in the container with a seal and if the container has another opening through which the second pressure can be supplied.
REFERENCES:
patent: 2979955 (1961-04-01), Shepler
patent: 4895026 (1990-01-01), Tada
patent: 5569856 (1996-10-01), Jacobs-Cook
patent: 41 32 391 (1992-10-01), None
patent: 0 164 413 (1985-12-01), None
patent: 0 753 728 (1997-01-01), None
patent: WO 85/02677 (1985-06-01), None
patent: WO 88/01049 (1988-02-01), None
Aw-Musse Abdullahi
BakerBotts LLP
Fuller Benjamin R.
Siemens Aktiengesellschaft
LandOfFree
Pressure differential measuring transducer does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pressure differential measuring transducer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pressure differential measuring transducer will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2484518