Capacitive differential pressure sensor
First Claim
1. Differential pressure sensor comprising a first ceramic body (20a) with a first membrane bed (22a), a second ceramic body (20b) with a second membrane bed (22b), a membrane (30), which is arranged between the two bodies (20a,20b) and separates the two oppositely situated membrane beds (22a, 22b) from one another, a first measurement capacitor K1 for producing a first measurement signal S1 with a first electrode pair (40a, 40b), which is present as one electrode on the membrane bed (22a) and one electrode on the membrane (30), a second measurement capacitor K2 for producing a second measurement signal S2 with a second electrode pair (41a, 41b), which is present as one electrode on the membrane bed (22b) and one electrode on the membrane (30), an electronic circuit which determines from the two measurement signals S1 and S2 the capacitances CK1, CK2 of the two measurement capacitors K1, K2, which produces a signal SIG1=1/CK1−
- 1/CK2, which is essentially proportional to the value of the pressure difference DP and which depends on the nominal pressure NP, which produces a signal SIG2=1/CK1+1/CK2, which is proportional to the value of the nominal pressure NP, wherein the dependence of the measurement value DP on the nominal pressure NP is corrected with the help of the signal SIG2.
1 Assignment
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Accused Products
Abstract
In a differential pressure sensor, the measurement value is corrected with the help of the nominal pressure NP. In this way, influences on the measurement value because of deformations of the body of the differential pressure sensor and change in the material stiffness of the membrane are decreased.
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Citations
5 Claims
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1. Differential pressure sensor comprising
a first ceramic body (20a) with a first membrane bed (22a), a second ceramic body (20b) with a second membrane bed (22b), a membrane (30), which is arranged between the two bodies (20a,20b) and separates the two oppositely situated membrane beds (22a, 22b) from one another, a first measurement capacitor K1 for producing a first measurement signal S1 with a first electrode pair (40a, 40b), which is present as one electrode on the membrane bed (22a) and one electrode on the membrane (30), a second measurement capacitor K2 for producing a second measurement signal S2 with a second electrode pair (41a, 41b), which is present as one electrode on the membrane bed (22b) and one electrode on the membrane (30), an electronic circuit which determines from the two measurement signals S1 and S2 the capacitances CK1, CK2 of the two measurement capacitors K1, K2, which produces a signal SIG1=1/CK1− - 1/CK2, which is essentially proportional to the value of the pressure difference DP and which depends on the nominal pressure NP,
which produces a signal SIG2=1/CK1+1/CK2, which is proportional to the value of the nominal pressure NP, wherein the dependence of the measurement value DP on the nominal pressure NP is corrected with the help of the signal SIG2. - View Dependent Claims (2, 3, 4, 5)
- 1/CK2, which is essentially proportional to the value of the pressure difference DP and which depends on the nominal pressure NP,
Specification