Flow-rate measurement assembly according to the differential-pressure measurement principle
A flow-rate measurement assembly for measuring a flow rate of a medium through a measurement pipe, comprising at least one differential-pressure producer, and comprising a differential-pressure measurement transducer for providing a differential-pressure measurement signal, which depends upon the difference between the high-pressure-side media pressure and the low-pressure-side media pressure. The difference is a measure of the flow rate of the medium. The evaluating unit is designed to determine a relationship between the differential-pressure measurement signal and a characteristic parameter of a fluctuation of the differential-pressure measurement signal, to judge the determination of a monotonically decreasing relationship between the differential-pressure measurement signal and the characteristic parameter to be an indication of a clogged high-pressure line, and to judge the determination of a monotonically increasing relationship between the differential-pressure measurement signal and the characteristic parameter, the monotonically increasing relationship of which is significantly stronger than the monotonically increasing relationship of an unclogged flow-rate measurement assembly, as an indication of a clogged low-pressure line.
1. A flow-rate measurement assembly for measuring a flow rate of a medium through a measurement pipe, said measurement pipe comprising:
at least one differential-pressure producer located in the measurement pipe, which differential-pressure producer brings about a reduction of a cross-sectional area through which the medium flows inside the measurement pipe in the region of said differential-pressure producer and thus a drop in the media pressure dependent upon the dimensions of said differential-pressure producer and upon the flow rate;
said measurement assembly comprising:
a differential-pressure measurement transducer for detecting a difference between a high-pressure-side media pressure and a low-pressure-side media pressure and for providing a differential-pressure measurement signal, which depends upon the difference between the high-pressure-side media pressure and the low-pressure-side media pressure, wherein the difference between the high-pressure-side media pressure and the low-pressure-side media pressure is a measure for the flow rate of the medium;
a high-pressure line, which is connected to a high-pressure inlet of said differential-pressure measurement transducer in order to apply the high-pressure-side media pressure to said differential-pressure measurement transducer,
a low-pressure line, which is connected to a low-pressure inlet of said differential-pressure measurement transducer in order to apply the low-pressure-side media pressure to said differential-pressure measurement transducer; and
an evaluating unit for evaluating the differential-pressure measurement signal, wherein:
said evaluating unit is designed to:
determine a relationship between the differential-pressure measurement signal and a characteristic parameter of a noise or of a fluctuation in the differential-pressure measurement signal,
judge the determination of a monotonically decreasing relationship between the differential-pressure measurement signal and the characteristic parameter to be an indication of a clogged high-pressure line; and
judge the determination of a monotonically increasing relationship between the differential-pressure measurement signal and the characteristic parameter, the monotonically increasing relationship of which is significantly stronger than the monotonically increasing relationship of an unclogged flow-rate measurement assembly, as an indication of a clogged low-pressure line.
2. The flow-rate measurement assembly according to claim 1 , wherein:
said monotonically increasing or decreasing relationship between the differential-pressure measurement signal and the characteristic parameter is approximately modeled by a linearly increasing or decreasing function; and
the significantly more strongly monotonically increasing relationship is an approximately linearly increasing function, the linear coefficient of which is significantly greater than the error-corrected linear coefficient of a linearly increasing function of an unclogged flow-rate measurement assembly.
3. The flow-rate measurement assembly according to claim 1 , wherein:
said monotonically increasing or decreasing relationship between the differential-pressure measurement signal and the characteristic parameter is approximately modeled by a quadratically increasing or decreasing function; and
the significantly more strongly monotonically increasing relationship is an approximately quadratically increasing function, the coefficient of the square term of which is significantly greater than the error-corrected coefficient of the square term of a quadratically increasing function of an unclogged flow-rate measurement assembly.
4. A method for monitoring a flow-rate measurement assembly, comprising the method steps of:
at least temporarily detecting a time curve of the differential-pressure measurement signal and a characteristic parameter of a noise or a fluctuation in the differential-pressure measurement signal;
determining a relationship between the differential-pressure measurement signal and a characteristic parameter of a noise or a fluctuation in the differential-pressure measurement signal, wherein the determination of a monotonically decreasing relationship between the differential-pressure measurement signal and the characteristic parameter is to be judged as an indication of a clogged high-pressure line; and
the determination of a monotonically increasing relationship between the differential-pressure measurement signal and the characteristic parameter, the monotonically increasing relationship of which is significantly stronger than the monotonically increasing relationship of an unclogged flow-rate measurement assembly, is to be judged as an indication of a clogged low-pressure line.