US 8,522,625 B2Granted

Flow measuring apparatus including a deflectable membrane applied to a constriction

AssigneeEndress + Hauser GmbH + Co. KG

InventorMichael Philipps

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Abstract

A flow measuring arrangement for measuring flow through a measuring tube comprises at least one constriction located in the measuring tube, which effects a reduction of a volume through which a medium flows; at least one deflectable membrane applied to said constriction, wherein deflection of the membrane effects a change of a volume through which medium flows in the measuring tube; a pressure measuring system connected to the measuring tube for measuring pressure (Δp, p); measuring electronics, which determines flow based on the measured pressure (Δp, p); an apparatus for producing a time variable deflection of the membrane and a diagnostic system, which determines an affect of said deflections of the membrane on the measured pressure (Δp, p), and which diagnoses the flow measuring arrangement based on the deflections and determined effects thereof on the measured pressure (Δp, p).

Claims17

Dependent claims

A flow measuring arrangement for measuring flow of a medium through a measuring tube, comprising:

at least one constriction located in the measuring tube which effects a reduction of a volume through which the medium flows internally in the measuring tube, and therewith a change in pressure conditions internally in the measuring tube, dependent on dimensions of said at least one constriction and dependent on flow;
a pressure measuring system connected to the measuring tube which serves to measure a pressure (Δp, p) dependent on flow through the measuring tube and dependent on the dimensions of said at least one constriction;
measuring electronics, which determines flow based on measured pressure (Δp, p) and the dimensions of said at least one constriction;
at least one deflectable membrane applied to one of the measuring tube constrictions internally in the measuring tube, wherein deflection of said at least one deflectable membrane effects a change, dependent on an amplitude of the deflection, of a volume through which medium flows internally in the measuring tube;
an apparatus for producing a time variable deflection of said at least one deflectable membrane according to a predetermined time-dependent deflection profile;
and,
a diagnostic system connected to said apparatus and to said pressure measuring system, which determines at least one effect of time-dependent changes of deflection of said at least one deflectable membrane on the measured pressure (Δp, p), and which produces a diagnosis of the functional ability of the flow measuring arrangement based on the predetermined time-dependent deflection profile and effects, as determined by the diagnostic system, of associated time-dependent changes of the deflection of said deflectable membrane on the measured pressure (Δp, p).

4 more elements

A method for monitoring functioning of a flow measuring system comprising:

at least one constriction located in the measuring tube which effects a reduction of a volume through which the medium flows internally in the measuring tube, and therewith a change in pressure conditions internally in the measuring tube, dependent on dimensions of said at least one constriction and dependent on flow;
a pressure measuring system connected to the measuring tube which serves to measure a pressure (Δp, p) dependent on flow through the measuring tube and dependent on the dimensions of said at least one constriction;
measuring electronics, which determines flow based on measured pressure (Δp, p) and the dimensions of said at least one constriction;
at least one deflectable membrane applied to one of the measuring tube constrictions internally in the measuring tube, wherein deflection of said at least one deflectable membrane effects a change, dependent on an amplitude of the deflection, of a volume through which medium flows internally in the measuring tube;
an apparatus for producing a time variable deflection of said at least one deflectable membrane according to a predetermined time-dependent deflection profile;
and,
a diagnostic system connected to said apparatus and to said pressure measuring system, which determines at least one effect on the measured pressure (Δp, p) caused by time-dependent changes of deflection of said at least one deflectable membrane, and which produces a diagnosis of the functional ability of the flow measuring arrangement based on the predetermined time-dependent deflection profile and effects, on the measured pressure (Δp, p), caused by associated time-dependent changes of the deflection of said deflectable membrane, the method comprising the steps of:
comparing via said diagnostic system said determined effects on measured pressure (Δp, p), caused by time changes of deflection of said deflectable membrane, with corresponding reference effects occurring in a flow measuring arrangement working properly in the case of the same predetermined deflection profile;
and,
on the basis of this comparison, create a diagnosis of functional ability of the flow measuring arrangement.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/923,701Filed 5 Oct 2010
Priority: DE 10 2009 045 3726 Oct 2009
Published: US 2011/0083515 A114 Apr 2011
Granted: 3 Sep 2013
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

G01F 1/3209
Using swirl flowmeters: using Karman vortices
G01F 1/22
By detection of dynamic effects of the flow: by variable-area meters , e.g. rotameters
G01F 1/36
By measuring pressure or differential pressure: the pressure or differential pressure being created by the use of flow constriction
G01F 1/42
Details of construction of the flow constriction devices: orifices or nozzles