DE102015011755A1 - Sensor for a sanitary device - Google Patents

Abstract

Measuring sensor (5) for a sanitary device (8) which can be arranged in a fluid line (4) of the sanitary device (8) and data-conducting connected to an evaluation device (7) of the sanitary device (8), wherein the measuring sensor (5) a capacitor (1 ) having a capacity which is variable due to an interaction of the probe (5) with a fluid (9) in the fluid line (4) and in dependence on at least one flow velocity of the fluid (9).

Description

The present invention relates to a measuring sensor for determining a fluid flow in a sanitary device or in a fluid line to a sanitary device.

In modern sanitary installations there is a need to determine the volume flow through water pipes. The most accurate knowledge of the flow of water through a pipe can be used, for example, for the precise adjustment of control valves or for the efficient heating of cold water in water heaters and the like.

Sensors for measuring a fluid flow in a conduit are known in the art. In this case, for example, impellers with blades made of an electrically conductive material and a coil arrangement are used, wherein the volume flow causes the impeller to move. Depending on the flow velocity, the blades are guided past the coil arrangement faster or slower. The approach and removal of electrical conductors induces in the coil a voltage that can be measured. The frequency of the induction voltage allows a conclusion on the flow velocity of the volume flow.

Furthermore, flow sensors are known which determine the flow velocity of electrically conductive fluids by means of Faraday induction.

The known sensors have the disadvantage that they either have rotating mechanical components, which can be used only at high flow rates for flow determination and easily block, and are expensive to produce, or can only determine the flow of electrically conductive media. Another problem is that these sensors are partially unsuitable for fluid lines of sanitary facilities, because at least temporarily present very low flow rates, which often have inaccurate measurement results to follow.

The present invention has the object of at least alleviating the problems mentioned with reference to the prior art. In particular, a cost-effective sensor is to be specified for small flow rates, which can determine the flow rate of conductive and non-conductive fluids. In particular, the sensor should be suitable for use in water fittings. Furthermore, the sensor should be versatile and, in addition to the flow velocity, can determine further properties of fluids, in particular a flow failure, the temperature and / or hardness of the fluid.

These objects are achieved with a sensor and a sanitary fitting according to the features of the independent claims. Further advantageous embodiments of the invention are specified in the dependent formulated claims. It should be noted that the features listed individually in the dependent formulated claims can be combined with each other in any technologically meaningful manner and define further embodiments of the invention. In addition, the features specified in the claims are specified and explained in more detail in the description, wherein further preferred embodiments of the invention are shown.

des Fluides veränderlich ist.For this purpose, a sensor for a sanitary device is proposed, which can be arranged in a fluid line of the sanitary device and data conducting connected to an evaluation device of the sanitary device, wherein the sensor comprises a capacitor having a capacity [C], which due to an interaction of the probe with the fluid in the Fluid line and in dependence on at least one flow rate

of the fluid is variable.

The sensor may be disposed in the fluid conduit, which may be, for example, a tubular conduit for water. The sensor can interact directly with the fluid. The main component of the sensor is, in addition to the necessary electrical wiring, a capacitor. The condenser is designed to change its capacity when the condenser is in contact with fluid of different flow rate. Thus, the capacity of the condenser can be directly influenced by the flow velocity of the fluid and, by evaluating this capacity, a direct conclusion can be drawn about the velocity of the volume flow.

The sensor or the condenser is in particular equipped with movable components whose orientation and / or position to one another is set differently due to the contact with the fluid at different flow velocities (independently or automatically).

The capacitor may comprise at least two plates. A mean distance [d] of the at least two plates may be variable due to the interaction of at least one of the plates with the fluid and depending on the flow rate of the fluid. The plates are preferred with their respective largest plate surfaces arranged approximately parallel and at a predetermined average distance from each other. The plates may be made of any electrically conductive material. A protective layer may be disposed around the plates to protect them from chemical attack by the fluid and short circuits from mutual contact. The protective layer may be, for example, an oxide layer.

As the mean distance [d] of the capacitor plates changes, the capacitance [C] of the capacitor also changes according to the formula: C = ε _o ∈ _r A / d, where [ε _o ] is the electric field constant of the vacuum, [ε _r ] the relative permittivity of the dielectric, here the fluid, and [A] the plate surface. If a volume flow of the fluid hits the plates at a flow velocity, so that at least one of the plates is displaced by a force [F →] as a result of the flow velocity with respect to the other plate, the mean distance of the plates from each other and consequently also the capacity of the plate changes capacitor. Of course, a plurality of plates of the capacitor can be designed to be movable.

The condenser may comprise at least two plates whose mutual surface coverage is variable due to an interaction of at least one of the plates with the fluid and the flow rate of the fluid. The capacity is primarily responsible for the overlapping area of the capacitor plates. Therefore, z. B. at a pivoting at least one of the plates in the plane of the plate increase or decrease the area coverage. The sensor is set up so that a movement / displacement of the plate (s) are caused in dependence on the flow velocity, whereby the capacity also changes due to the change of the overlapping surface of the plates.

It is preferred that at least one plate of the capacitor is translationally and / or rotationally displaceable or pivotable relative to another plate.

For a change in mean spacing, the at least one plate is moved toward or away from the other plate by a force perpendicular to the plane of the plate (which is parallel to the largest plate surface of the plate). The deflection of the movable plate is in this case dependent on the force caused by and corresponding to the flow velocity of the fluid. This can be achieved with free movement of the plate by a return element such as a spring during translation or a torsion spring during rotation.

For a change in area coverage, the at least one plate is displaced parallel to the plane of the plate relative to the other plate. This displacement is dependent on the force caused by and corresponding to the flow velocity of the fluid. Therefore, a return element in the form of a spring for translational movements and in the form of a torsion spring for rotational movements is provided.

At least one of the plates may also be displaceable relative to the other plate by elastic deformation.

According to a further aspect, the use of a measuring sensor proposed here for determining a flow velocity of a fluid in a fluid line of a sanitary device is proposed.

The sanitary device may be a water supply system for or comprising a water closet, a shower, a bath, a hotplate, a drinking water dispenser, a sink, and / or a urinal. The sensor of the type described above comprises a condenser and can be used for determining the flow velocity in the fluid line by evaluating the capacity which changes according to the velocity of the volume flow. Such a sensor works without any paddle wheels, which means that even very small volume flows and flow velocities can be detected. In particular, the sensor can also be used to determine at least one of the following additional properties of water: water temperature, water hardness, air inclusions or lack of water.

• a) Bereitstellen einer Fluidleitung mit einer Messschaltung aufweisend einen Schwingkreis und hier vorgeschlagenen Messfühler;
• b) Erfassen von Signalen der Messschaltung;
• c) Vergleichen der Signale in einer Auswertungseinrichtung der Sanitäreinrichtungen mit mindestens einem Referenzparameter;
• d) Einstellen eines Stellgliedes der Sanitäreinrichtung in Abhängigkeit des Ergebnisses des Vergleichs aus Schritt c).

Furthermore, a method for operating a sanitary device is proposed which comprises at least the following steps:

• a) providing a fluid line with a measuring circuit having a resonant circuit and proposed here probe;
• b) detecting signals of the measuring circuit;
• c) comparing the signals in an evaluation device of the sanitary facilities with at least one reference parameter;
• d) setting an actuator of the sanitary device depending on the result of the comparison of step c).

Step a) relates in particular to the mechanical and electronic installation of a sensor of the type proposed here in a water-carrying pipe of a sanitary device. Therefore the appropriate electrical and data connections should be in place and available. Step b) can then be initiated permanently at desired times or else (possibly in phases) and generate or deliver measurement data relating to the current capacitance of the capacitor. These measurement signals (or electrical variables) are then transported in accordance with step c) from the measurement circuit to an evaluation device, where these are compared with reference parameters. For this purpose, the evaluation device can be equipped with reference parameters which, based on the current measurement signals, can (at least) infer an actual flow velocity of the fluid / water. Furthermore, the measuring signals can also be used in order to draw conclusions about the current temperature of the water and / or the water hardness with (other) reference values. Also, it can thus be monitored whether there is any fluid or water in the fluid line. Based on the result of the comparison and thus an analysis of the measurement signals, actuation of an actuator of the sanitary device can then be carried out as required (step d)), which can be set electronically (directly or indirectly), in particular by means of the evaluation device. For example, a flow characteristic of the fluid may be readjusted at a specific location of a fluid line of the sanitary device, such as by means of valves, thermostats, switches, orifices, or similar actuators. This allows a particularly precise and energy-saving operation, as z. B. is desired for water fittings. Also cleaning and / or maintenance procedures may be initiated if necessary.

• i. Die Kapazität des Kondensators des Messfühlers wird aufgrund einer (unmittelbaren) Wechselwirkung des Messfühlers mit dem Fluid und in Abhängigkeit von der Strömungsgeschwindigkeit des Fluides verändert.
• ii. Zumindest eine elektrische Größe der Messschaltung, welche einen elektrischen Schwingkreis hat, dessen kapazitiver Teil den Kondensator umfasst, wird durch die veränderte Kapazität verändert.
• iii. Die Strömungsgeschwindigkeit wird aus der zumindest einen elektrischen Größe der Messschaltung durch eine Auswertungseinrichtung ermittelt.

In the method for determining a flow velocity, in particular the following processes are carried out:

• i. The capacitance of the capacitor of the probe is changed due to a (direct) interaction of the probe with the fluid and depending on the flow rate of the fluid.
• ii. At least one electrical variable of the measuring circuit, which has an electrical resonant circuit whose capacitive part comprises the capacitor, is changed by the changed capacitance.
• iii. The flow velocity is determined from the at least one electrical variable of the measuring circuit by an evaluation device.

wobei [L] der Induktivität des induktiven Teils des Schwingkreises und [C] der Kapazität des Kondensators bzw. des kapazitiven Teils des Schwingkreises entspricht. Die Auswertungseinrichtung kann diese Veränderung erfassen und einer entsprechenden Strömungsgeschwindigkeit des Fluides in der Fluidleitung zuordnen bzw. berechnen. Somit lässt sich mit kostengünstigen und zuverlässigen elektrischen Komponenten die Strömungsgeschwindigkeit von Fluiden besonders präzise ermitteln.The capacitance which changes according to the flow velocity influences the oscillation behavior of the resonant circuit by changing the natural frequency [ω ₀ ] according to the formula:

where [L] corresponds to the inductance of the inductive part of the resonant circuit and [C] to the capacitance of the capacitor or the capacitive part of the resonant circuit. The evaluation device can detect this change and allocate or calculate it to a corresponding flow velocity of the fluid in the fluid line. Thus, with low-cost and reliable electrical components, the flow rate of fluids can be determined very precisely.

In the method, the resonant circuit can receive a voltage pulse from a current source and the flow rate of the fluid can be determined by a decay curve of the voltage pulse. The capacitor is at least partially charged by the voltage pulse of the power source. The height of the charge is determined by the capacity, so that the discharge process allows statements about the capacity and thus the flow velocity.

In the method, the resonant circuit can alternatively be excited by a current source with a voltage in a natural frequency of the resonant circuit and the flow velocity of the fluid can be determined by changing a voltage profile of the resonant circuit.

In particular for carrying out the method explained above, a suitable device is also proposed. The device comprises at least one fluid line, a measuring circuit and an evaluation device. In this case, the measuring circuit comprises a resonant circuit and a measuring sensor. The probe comprises a capacitor whose capacitance is variable due to an interaction of the probe with a fluid in the fluid conduit and in dependence on the flow rate of the fluid. The capacitive part of the resonant circuit comprises the capacitor. The evaluation device is set up to determine a flow velocity of the fluid from at least one electrical variable of the measuring circuit. For additional description of the probe can also be used on the previous versions.

The resonant circuit may consist of at least one series connection or a parallel connection of a coil and a capacitor, which is part of the sensor. The capacitor is connected in parallel with a voltage source which can either supply an electrical voltage pulse for charging the capacitor and / or can excite the resonant circuit with an adjustable frequency. The Evaluation device may be an analog circuit, a digital circuit, an integrated circuit such as a microcontroller (.mu.C), a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), etc. or a PC. The evaluation device can, for example, have stored reference values for the correlation of measured value and flow velocity and / or corresponding calculation instructions starting from an operating point (reference value) in a reference table.

The probe proposed here can also be used to deduce the general presence of a fluid, because the capacity depends on the relative permittivity [ε _r ], which is a substance constant. The relative permittivity of water at 20 ° C is about 80 and that of air about 1,00059, so that according to the aforementioned formula for the capacity results in a significantly different result in the event that air is present in a water pipe instead of water.

The temperature can also be determined by changing the relative permittivity [ε _r ] and thus by changing the capacitance. The relative permittivity of water at 0 ° C is about 88, so that there is a difference of about 10% in the capacity between 0 ° C and 20 ° C. Consequently, if there is a reference measure of the temperature or the flow velocity remains constant, it can be concluded from a change in the capacity to the temperature.

A possible reference value for the temperature can be obtained, for example, from the compensation gap of a thermostat, which is connected upstream of the fluid line with the measuring sensor proposed here. This makes it possible that the temperature determined by the thermostat is taken into account in the analysis of the measurement results of the probe in order to make even more accurate calculations here.

Also, the water hardness, which makes a statement about the electrolytes in the fluid and thus influences the conductivity of the fluid and its relative permittivity [ε _r ] can be detected with such a sensor or method, if a corresponding reference is present.

For connecting the measuring circuit to commercially available evaluation devices such as PCs, it is advantageous to provide a general or standardized interface.

The evaluation can preferably be carried out by a software program which can be loaded into the memory of an evaluation device.

The invention and the technical environment will be explained in more detail with reference to FIGS. It should be noted that the figures show a particularly preferred embodiment of the invention, but this is not limited thereto. The same components are provided in the figures with the same reference numerals. They show by way of example and schematically:

1 a capacitor in a fluid flow;

2 a rotational displacement of a plate of a capacitor;

3 : an elastic deformation of a plate of a capacitor.

4 a translational displacement of a plate of a capacitor;

5 a translatory displacement of a plate of a capacitor in its plate plane;

6 a rotational displacement of a plate of a capacitor in its plate plane;

7 a device for determining a flow rate of a fluid; and

8th a sanitary device with a device for determining a flow velocity of a fluid.

1 schematically shows a capacitor 1 , The capacitor 1 includes two plates, a first plate 2 and a second plate 3 , The plates 2 . 3 are symmetrical and equal in size, but can also be asymmetrical and different sizes. They each have two surfaces (plate surfaces) parallel to a plate plane, which are larger than the remaining surfaces. Said plate surfaces of the two plates 2 . 3 are aligned in a middle distance 12 across from. The plates 2 . 3 consist of an electrically conductive Matetrial, z. As copper, aluminum, etc., and are connected to a voltage source 13 connected. The voltage source 13 may be a DC or AC source. The capacitor 1 is with its plates at least partially in a fluid 9 immersed. The fluid 9 has a flow velocity [V] which is at least the second plate 3 exerts a force [F].

The 2 to 4 schematically show possible forms of displacement of the second plate 3 opposite the first plate 2 by the force [F] due to the flow velocity [V] of the fluid 9 , By the respective deflection, the middle distance 12 the plates changed, which has a direct impact on the capacity of the capacitor 1 Has. The same applies to a shift of the first plate 2 opposite the second plate 3 ,

The flow of the fluid 9 preferably meets perpendicular to the plate surfaces of the plates 2 . 3 to get as much power [F] as possible.

In 2 becomes a rotational deflection or pivoting of the second plate 3 opposite the first plate 2 shown. By the force [F] becomes the second plate 3 on a circular path perpendicular to the plate surface of the first plate 2 moved away. Of course, an opposite flow and resulting direction of movement is possible. Due to the increased average distance 12 between the plates also changes the capacitance of the capacitor 1 , where the capacity is linear with the mean distance.

The second plate 3 is in 3 elastically deformed by the force [F] of the flow and thus of the first plate 2 moved away. An opposite flow and displacement is also possible. The capacity of the capacitor 1 changes linearly with the mean distance 12 between the plates 2 . 3 ,

4 schematically shows a translational displacement of the second plate 3 opposite the first plate 2 due to the force [F] of the fluid at the flow velocity [V] on the second plate 3 , A shift in the opposite direction with opposite flow is also possible. The translational displacement of the second plate also changes the mean distance 12 between the plates 2 . 3 and consequently the capacitance of the capacitor 1 ,

In the 5 and 6 schematically two possible forms of a Flächenüberdeckungsveränderung are shown. The capacity of the capacitor 1 depends on the directly overlapping area of the opposing plates 2 . 3 from. If the surface coverage by the force [F] on one of the plates 2 . 3 changed, the capacitance of the capacitor changes to the same extent 1 , At one of the plates 2 . 3 For example, an element for increasing the flow resistance may be attached to the force from the fluid 9 on for example the second plate 3 opposite the first plate 2 to increase. The flow of the fluid 9 runs preferably parallel to the plate surfaces of the capacitor 1 To maximize the force required to move one of the plates 2 . 3 to get in the disk plane.

5 schematically shows a translational displacement of the second plate 3 opposite the first plate 2 due to the force [F] of the fluid 9 , This changes the capacitance of the capacitor 1 according to the velocity of the flow of the fluid 9 ,

In 6 is a rotational displacement or pivoting of the second plate 3 opposite the first plate 2 shown. By the rotation of one of the plates 2 . 3 changes the area coverage and the capacitance of the capacitor is equally affected.

All previously shown types of displacement of the plates 2 . 3 lead to a direct and almost linear influence on the capacitance of the capacitor 1 and can be combined with each other.

7 shows a device 15 for determining a flow velocity of a fluid 9 , A measuring circuit 6 includes a sensor 5 with the capacitor 1 and a resonant circuit 10 , The capacitor 1 is part (main part) of the capacitive part of the resonant circuit 10 , By changing the capacitance of the capacitor 1 by the flow velocity [V] of the fluid 9 the natural frequency of the resonant circuit is changed. This can be achieved by an evaluation device 7 a sanitary facility 8th via a data line 11 capture and a flow rate of the fluid 9 assign. With this information about the flow of the fluid 9 can be an actuator 14 a sanitary facility 8th be controlled automatically and so z. B. a valve accordingly further opened or closed.

8th shows a sanitary device 8th For example, a water tap. fluid 9 , here water, is in a thermostat 16 tempered. The flow velocity of the fluid 9 is in a fluid line 4 indirectly by capacitance change in the measuring circuit 6 with the probe 5 measured and in the evaluation device 7 determined. A change in the relative permittivity of the water due to the temperature control in the thermostat 16 can by means of transmission of a reference temperature of the thermostat 16 to the evaluation device 7 be taken into account in determining the flow velocity [V].

LIST OF REFERENCE NUMBERS

1

capacitor

2

first plate

3

second plate

4

fluid line

5

probe

6

measuring circuit

7

evaluation device

8th

sanitary facilities

9

fluid

10

resonant circuit

11

data line

12

distance

13

voltage source

14

actuator

15

contraption

16

thermostat

Claims (8)

Sensor ( 5 ) for a sanitary facility ( 8th ), which is in a fluid line ( 4 ) of the sanitary facility ( 8th ) and with an evaluation device ( 7 ) of the sanitary facility ( 8th ) can be connected in terms of data, the sensor ( 5 ) a capacitor ( 1 ) having a capacity which due to an interaction of the probe ( 5 ) with a fluid ( 9 ) in the fluid line ( 4 ) and in dependence on at least one flow velocity of the fluid ( 9 ) is changeable. Sensor ( 5 ) according to claim 1, wherein the capacitor ( 1 ) at least two plates ( 2 . 3 ) whose mean distance ( 12 ) due to an interaction of at least one of the plates ( 2 . 3 ) with the fluid ( 9 ) and depending on the flow rate of the fluid ( 9 ) is changeable. Sensor ( 5 ) according to claim 2, wherein the capacitor ( 1 ) at least two plates ( 2 . 3 ) whose mutual surface coverage due to an interaction of at least one of the plates ( 2 . 3 ) with the fluid ( 9 ) and depending on the flow rate of the fluid ( 9 ) is changeable. Sensor ( 5 ) according to one of the preceding claims, wherein at least one of the plates ( 2 . 3 ) is translationally and / or rotationally displaceable relative to another plate. Sensor ( 5 ) according to one of the preceding claims, wherein at least one of the plates is displaceable relative to the other plate by elastic deformation. Using a probe ( 5 ) according to one of the preceding claims for determining a flow velocity of a fluid ( 9 ) in a fluid line ( 4 ) of a sanitary facility ( 8th ). Method for operating a sanitary device ( 8th ), comprising at least the following steps: a) providing a fluid line ( 4 ) with a measuring circuit ( 6 ), comprising a resonant circuit ( 10 ) and a sensor ( 5 ) according to any one of the preceding claims 1 to 6; b) detecting signals of the measuring circuit ( 6 ); c) comparing the signals in an evaluation device ( 7 ) of sanitary facilities ( 8th ) with at least one reference parameter; d) setting an actuator ( 14 ) of the sanitary facility ( 8th ) depending on the result of the comparison from step c). Contraption ( 15 ), at least comprising a fluid line ( 4 ), a measuring circuit ( 6 ) and an evaluation device ( 7 ), the measuring circuit ( 6 ) a resonant circuit ( 10 ) and a sensor ( 5 ), the sensor ( 5 ) a capacitor ( 1 ) whose capacity due to an interaction of the probe ( 5 ) with a fluid ( 9 ) in the fluid line ( 4 ) and depending on the flow rate of the fluid ( 9 ) is variable, the capacitive part of the resonant circuit ( 10 ) the capacitor ( 1 ) and the evaluation device ( 7 ) is adapted to at least one electrical size of the measuring circuit ( 6 ) a flow rate of the fluid ( 9 ) to investigate.

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