FR3129206A1 - Fluid detector - Google Patents

Abstract

The invention relates to a fluid detector (1) comprising an electromagnetic waveguide (2) comprising a substrate (3), said substrate comprising a material whose dielectric constant has at least a first value representative of the absence of the fluid in the material and a second value representative of the presence of the fluid in the material, and in that it comprises means for measuring a parameter representative of the value of the dielectric constant of the material. Figure for abstract: Fig. 1

Description

Fluid detector

Technical field of the invention

The present invention generally relates to the detection of fluids, and in particular the detection of leaks of such fluids.

Technical background

Leak detection or tightness control is one of the disciplines that is part of the control techniques implemented in a large number of industries or applications. Multiple products use techniques for detecting, measuring and locating leaks either because the fluid that we are trying to confine inside or outside an envelope is expensive, available in limited quantities , dangerous, toxic, harmful to the environment, capable of causing damage around the point of leakage, or has the purpose of transforming an atmosphere for the preservation of a content or the reduction of a risk. There are non-destructive methods, for example by tracer gas, and there are also invasive methods, for example by pressure attenuation, or by flow measurement.

The leakage flux or leakage rate is expressed in different units depending on the intended application. In refrigeration, we will generally speak in grams per year to designate the loss of refrigerant in one year (for example: the limit leak rate on automobile air conditioning is 5 g/year). In others, the millibar liter per second or mb.l/s or the atmosphere cubic centimeter per second or atm.cm3/s will be used. The unit used in the metric system is the pascal cubic meter per second or Pa.m3/s.

All of these techniques aim to detect the presence of a fluid in a given environment which, in an application example, may reveal the existence of a leak.

There are methods based on tracer gases. However, these methods are complex to implement and are not suitable for permanent monitoring of a given environment.

There are also methods based on measuring the variation in pressure over time or measuring the flow rate or even detecting acoustic waves specific to the fluid leak sought.

All these methods induce additional efforts which cause high costs and a relatively large investment of time.

Based on this problem, the present invention therefore has the task of developing a novel fluid sensor that is inexpensive and simple to implement.

With regard to fluid detectors, the task on which the invention is based is solved by the subject matter of independent claim 1, advantageous developments of the fluid detector according to the invention being specified in dependent claims 2 to 5. .

Consequently, the invention relates in particular to a fluid detector comprising an electromagnetic waveguide comprising a substrate, said substrate comprising a material whose dielectric constant has at least a first value representative of the absence of the fluid in the material and a second value representative of the presence of the fluid in the material, the detector comprising means for measuring a parameter representative of the value of the dielectric constant of the material

Preferably, the substrate is a substrate of the type that can be impregnated with

Preferably, the substrate is a fabric comprising threads of dielectric material.

Preferably, the electromagnetic waveguide is a microstrip line comprising a first electrical conductive strip secured to a first face of the substrate and a second electrical conductive strip secured to a second face of the substrate.

Preferably, the first and second conductive strips are sewn onto the fabric.

The invention further relates to a method for manufacturing a fluid sensor, in particular a fluid sensor of the type according to the invention indicated above.

Brief description of figures

Other characteristics and advantages of the invention will appear during the reading of the detailed description which will follow for the understanding of which reference will be made to the appended drawings in which:

shows schematically and in an isometric view, an exemplary embodiment of a fluid detector 1 according to the invention;

schematically shows the exemplary embodiment of the detector according to the invention according to the ;

schematically shows the exemplary embodiment of the detector according to the invention according to the ;

schematically shows the exemplary embodiment of the detector according to the invention according to the ; And

illustrates the effect of wetting or drying the detector according to the invention of the on an oscilloscope.

Claims (5)

Fluid detector (1) characterized in that it comprises an electromagnetic waveguide (2) comprising a substrate (3), said substrate comprising a material whose dielectric constant has at least a first value representative of the absence of the fluid in the material and a second value representative of the presence of the fluid in the material, and in that it comprises means for measuring a parameter representative of the value of the dielectric constant of the material. Fluid sensor (1) according to claim 1, characterized in that the substrate (3) is a substrate of the type capable of being impregnated with fluid. Fluid detector (1) according to either of Claims 1 and 2, characterized in that the substrate (3) is a fabric comprising threads of dielectric material. Fluid detector (1) according to any one of Claims 1 to 3, characterized in that the electromagnetic waveguide (2) is a microstrip line comprising a first electrically conductive strip (4) secured to a first face of the substrate and a second electrically conductive strip (5) secured to a second face of the substrate. Fluid detector (1) according to claims 3 and 4, characterized in that the first and second conductive strips are sewn onto the fabric.