DE102015121412A1 - Measuring system of process automation technology - Google Patents

Abstract

The invention relates to a measuring system of the process automation technology for measuring a plurality of process variables of a medium in a conduit, comprising a sensor body (1) for attachment to a conduit, so that the sensor body (1) at least partially protrudes into a guided in the conduit medium, wherein the sensor body (1) has a first sensor for determining at least one process variable of the medium in the line, wherein the sensor body (1) comprises a second sensor, which converts a deformation of the sensor body (1) into electrical signals, so that at least one process variable of the medium the electrical signals can be determined by means of an evaluation unit.

Description

The invention relates to a measuring system of process automation technology for measuring a plurality of measured quantities of a medium in a line.

A sensor is a technical component that quantitatively measures certain physical or chemical properties (physical eg amount of heat, temperature, humidity, pressure, sound field parameters, brightness, acceleration or chemical eg pH value, ionic strength, electrochemical potential) can capture. These quantities are detected by means of physical or chemical effects and converted into a further processable electrical signal.

For each of these properties there is a separate sensor that must be installed in a test setup. If several properties of a medium are to be measured simultaneously as measured variables, a sensor must be installed in the test setup for each measured variable of the medium. This is associated with high installation and maintenance costs.

The object of the invention is to specify a sensor which is capable of simultaneously determining a plurality of measured variables of a medium and can be produced cost-effectively.

The object is achieved by the subject matter of the invention. The invention relates to a measuring system of the process automation technology for measuring a plurality of measured quantities of a medium in a line, comprising a sensor body for attachment to a line, so that the sensor body protrudes at least partially into a guided in the conduit medium, wherein the sensor body comprises a first sensor for determining at least one process variable of the medium in the line, wherein the sensor body comprises a second sensor which converts a deformation of the sensor body into electrical signals, so that at least one measured variable of the medium from the electrical signals can be determined by means of an evaluation unit.

Since the sensor body is compact and at the same time is able to measure a plurality of measured variables and can be easily attached to a line, the sensor body can be produced inexpensively.

According to an advantageous variant, the sensor body has a process connection which can be connected to a side flange of the line.

According to an advantageous embodiment, the first sensor is designed as a conductivity sensor, in particular as a conductive conductivity sensor or as a pH or an oxygen sensor, in particular as an amperometric oxygen sensor.

According to an advantageous embodiment, the second sensor is designed as a flow sensor which displays a flow, in particular a flow rate of the medium or as a pH or an oxygen sensor, in particular designed as an amperometric oxygen sensor. There is a synergistic effect between conductivity sensors and amperometric oxygen sensors because amperometric oxygen sensors require a minimum flow to generate stable readings.

According to a favorable development, the second sensor comprises at least one strain gauge, which converts a deformation of the sensor body into electrical signals.

According to a favorable variant, the evaluation unit is designed as a bridge circuit, in particular a full-bridge circuit for evaluating the electrical signals of the second sensor.

According to a favorable embodiment, the second sensor comprises a light emitter and a light receiver, wherein the light emitter and the light receiver are arranged such that a deformation of the sensor body caused by the flow of the medium results in a change of the beam direction of the light emitter.

According to a favorable embodiment, a reflector is provided which reflects the light of the light emitter in the direction of the light receiver.

According to an advantageous embodiment, the sensor body on plastic. Plastic housings are flexible. Therefore, a deformation is better measurable.

The invention will be explained in more detail with reference to the following drawings. It shows:

1a FIG. 2: a longitudinal section of a measuring system with strain gauges arranged on an inner wall of the sensor body, FIG.

1b : a longitudinal section of a measuring system accordingly 1a which protrudes into a flowing medium,

2a : shows a longitudinal section of a measuring system accordingly 1a with an optical system for determining the flow, and

2 B : a longitudinal section of a measuring system accordingly 2a which protrudes into a flowing medium.

1a shows a longitudinal section of a measuring system 7 the process automation technology for measuring a plurality of process variables of a medium (not shown) in a line (not shown). The measuring system 7 includes a sensor body 1 comprising a first sensor configured as a conductive conductivity sensor (not shown).

The sensor body 1 has a second sensor, the two strain gauges 2 includes. The strain gauges 2 are on an inner wall of the sensor body 1 arranged and connected to an evaluation unit (not shown), which is designed as a full bridge circuit and for the evaluation of the electrical signals of the strain gauges 2 serves. Furthermore, the sensor body 1 a process connection 8th on, which is connectable to a side flange of the line.

1b shows a longitudinal section of a measuring system 7 corresponding 1a , wherein the sensor body 1 by means of the process connection 8th on a side flange (not shown) of the line is connected, so that the sensor body 1 exposed to a flowing medium. The flowing medium causes a back pressure 3 on a surface of the sensor body 1 so that the sensor body 1 is deformed.

The strain gauges 2 change the deformation of the sensor body 1 into electrical signals, so that from the electrical signals by means of an evaluation unit, the flow or the flow velocity can be determined.

2a shows a longitudinal section of a measuring system 7 corresponding 1a with an optical system for determining the flow of the medium. The optical system includes a light emitter 4 , a light receiver 5 and a reflector 6 , The light transmitter 4 emits light coming from the reflector 6 in the direction of the light receiver 5 is reflected.

2 B shows a longitudinal section of a measuring system 7 corresponding 2a , which is held in a flowing medium. Due to the flow of the medium creates a back pressure 3 on the surface of the sensor body 1 , which is a deformation of the sensor body 1 entails. The light transmitter 4 , the light receiver 5 and the reflector 6 are arranged so that a deformation of the sensor body 1 , a change in the beam direction of the light emitter 4 entails. The change in the jet direction is a measure of the flow rate and is registered and evaluated accordingly by an evaluation unit.

The evaluation unit is the same device that also evaluates the measured values of the conductivity sensor. As a result, the measuring system becomes even more compact and the evaluation unit can relate the measured values of the first and second sensors to one another, e.g. for diagnostic purposes or for more accurate measured value determination.

LIST OF REFERENCE NUMBERS

1

 sensor body

2

 Strain gauges

3

 backpressure

4

 light source

5

 light receiver

6

 reflector

7

 measuring system

8th

 process connection

Claims (9)

Measuring system of process automation technology for measuring a plurality of process variables of a medium in a line, comprising a sensor body ( 1 ) for attachment to a conduit so that the sensor body ( 1 ) projects at least partially into a medium conducted in the conduit, wherein the sensor body ( 1 ) has a first sensor for determining at least one process variable of the medium in the conduit, wherein the sensor body ( 1 ) has a second sensor which detects a deformation of the sensor body ( 1 ) is converted into electrical signals, so that at least one process variable of the medium from the electrical signals can be determined by means of an evaluation unit. Measuring system according to claim 1, wherein the sensor body ( 1 ) a process connection ( 8th ), which is connectable to a side flange of the line. Measuring system according to claim 1 or 2, wherein the first sensor is configured as a conductivity sensor, in particular a conductive conductivity sensor or as a pH or an oxygen sensor, in particular as an amperometric oxygen sensor. Measuring system according to at least one of the preceding claims, wherein the second sensor is designed as a flow sensor, which indicates a flow, in particular a flow rate of the medium. Measuring system according to at least one of the preceding claims, wherein the second sensor at least one strain gauge ( 2 ), which is a deformation of the sensor body ( 1 ) is converted into electrical signals. Measuring system according to at least one of the preceding claims, wherein the evaluation unit is designed as a bridge circuit, in particular a full-bridge circuit for evaluating the electrical signals of the second sensor. Measuring system according to at least one of claims 1 to 4, wherein the second sensor comprises a light transmitter ( 4 ) and a light receiver ( 5 ), and wherein the light emitter ( 4 ) and the light receiver ( 5 ) are arranged so that a caused by the flow of the medium deformation of the sensor body ( 1 ) a change in the beam direction of the light emitter ( 4 ). Measuring system according to claim 7, wherein a reflector ( 6 ) is provided, the light of the light emitter ( 4 ) in the direction of the light receiver ( 5 ) reflected. Measuring system according to at least one of the preceding claims, wherein the sensor body ( 1 ) Plastic.

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