DK201870652A1

DK201870652A1 - Sensor device with probe

Info

Publication number: DK201870652A1
Application number: DKPA201870652A
Authority: DK
Inventors: Hansen Morten; Hoveroust Dupont Sune; Christiansen Uffe
Original assignee: Kamstrup A/S
Priority date: 2018-10-03
Filing date: 2018-10-03
Publication date: 2019-10-03

Abstract

A sensor device arranged for measuring the quality of water or another fluid flowing in a flow pipe. The sensor device comprises a flow part provided with a fluid passage extending between an inlet and outlet and constituting a measurement section; a sensor unit arranged in a housing provided in association with the flow part is configured for measuring a quality parameter of a fluid in the measurement section; and a battery pack arranged in the housing for powering the processing unit. Further the sensor device comprises a probe mounted on the flow part for insertion into the flow pipe, the probe including an inlet channel in fluid communication with the inlet of the fluid passage and an outlet channel in fluid communication with the outlet of the fluid passage.

Description

SENSOR DEVICE WITH PROBE

FIELD OF THE INVENTION

The present invention relates to a sensor for measuring the quality of water or another fluid distributed through a utility network. In particular, the measurement of acoustic turbidity of drinking water produced and distributed by utilities in closed pipes.

BACKGROUND OF THE INVENTION

Worldwide the consumption of drinking quality is increasing. Drinking water is retrieved from underground wells, but also surface water or even de-salted sea water are used as drinking water. Thus, there is a demand for utility companies to measure the quality of water distributed through the utility network.

A complete analysis of water quality involves complicated biochemical analyses, however in some cases a measure of water quality obtained by means of a measurement can be sufficient, i.e. measurement of the amount of particles in the fluid as a measure of cleanness of the fluid.

Such measurements is traditionally based on optical methods. However optical turbidity equipment is not well-suited for functioning as a permanently mounted part of a utility network due to the forming of coatings of minerals and/or biofilms on the optical surfaces, which will disturb the measurements and necessitate frequent maintenance. Furthermore, optical measurement equipment is often expensive and can thus in practice only be installed at a limited number of positions in a utility network.

Systems and devices for measuring acoustic turbidity are also known, such as the ultrasonic fluid flow measurement device disclosed by the applicant in the international patent application WO 2017/005268.

Devices for being installed throughout a utility network must be standalone devices that are robust to harsh environments and does not requiring a mains powered power supply. Further, such devices should preferable not require regular maintenance and measured data should preferably be available remotely, e.g. by collection via known advanced meter infrastructure (AMI) or automatic meter reading (AMR) systems.

A need therefore exists for a cost-effective and robust standalone acoustic turbidity sensor suitable for installation at remote locations in a utility network.

DK 2018 70652 A1

OBJECT OF THE INVENTION

An object of the present invention is to provide a cost-effective standalone fluid sensor suitable for installation at remote locations in a utility network. Specifically, an object of the invention is to provide a standalone acoustic turbidity sensor.

SUMMARY OF THE INVENTION

Thus, the above described object and several other objects are intended to be obtained in a first aspect of the invention by providing a sensor device arranged for measuring quality of a fluid flowing in a flow pipe, the sensor device comprising a flow part provided with a fluid passage extending between an inlet and outlet, wherein part of the fluid passage constitutes a measurement section; a sensor unit arranged in a housing provided in association with the flow part, the sensor being configured for sensing a fluid parameter, such as fluid flow or a fluid quality parameter, of a fluid in the measurement section; a battery pack arranged in the housing for powering the sensor unit; characterized in the sensor device further comprises a probe mounted on the flow part for insertion into the flow pipe, the probe including an inlet channel extending between a probe inlet opening provided on one side of the probe and the inlet of the fluid passage and an outlet channel extending between the outlet of the fluid channel and a probe outlet opening provided on a side of the probe opposite the inlet opening.

Hereby a sensor device for measuring the quality of a fluid flowing in a flow pipe is provided as fluid may be sampled from the flow pipe and run through the fluid passage of the flow part including the measurement section, before the fluid is returned to the flow pipe.

In one embodiment, the sensor device is configured for measuring acoustic turbidity of a fluid flowing in the flow pipe, here the sensor unit includes first and second ultrasound transducers configured for transmitting and receiving ultrasonic signals through a fluid in the measurement section; and the sensor device further comprises a processing unit operationally connected to a measurement circuit arranged in the housing, the measurement circuit including the first and second ultrasound transducers and the processing unit being configured for operating the ultrasound transducer to generate a digital signal indicative of the acoustic turbidity of the fluid in response to one or more ultrasonic signals received by one of the ultrasound transducers.

DK 2018 70652 A1

Hereby a sensor device for measuring the acoustic turbidity of a fluid flowing in a flow pipe is provided.

In other embodiments the sensor unit may include a pressure sensors for measuring fluid pressure, either absolute pressure or a differential pressure. Alternatively, the sensor unit may include a biological sensor or a conductivity sensor, such as a conductivity sensor configured for determining the chlorine concentration in a fluid, such as water.

Further, by the probe inlet opening and the outlet opening being provided on opposite sides of the probe facing in opposite directions, the probe may be inserted into a flow pipe with the inlet facing upstream and the outlet facing downstream. Doing this, the fluid flowing in the flow pipe creates a pressure prop between the inlet and the outlet resulting in fluid from the flow pipe being drawn into the probe inlet channel, through the fluid passage of the flow part and out through the probe outlet channel and probe outlet opening. Herby fluid is circulated through the measurement section without the need of for example an electrical pump.

Additionally, the probe outlet opening may be larger than the probe inlet opening. By making the probe outlet larger than the probe outlet, the hydrodynamic resistance of the channel through the sensor device is reduced and the circulation of fluid through the flow part and measurement section is improved.

The invention further relates to an insertion device for inserting the probe of the above-mentioned sensor device into a pressurized flow pipe, the insertion device may include a plurality of cylinders cooperating to provide a telescopic mechanism adapted to pull the probe into the flow pipe by rotating the sensor device. The cylinders may include threads or other mechanism enabling mutual engagement of the cylinders and allowing the position of the cylinders to be locked in relation to one another.

These and other aspects of the invention will be apparent from the dependent claims and elucidated with reference to the embodiments described hereinafter.

DK 2018 70652 A1

BRIEF DESCRIPTION OF THE FIGURES

The acoustic turbidity sensor device according to the invention will now be described in more detail with reference to the accompanying figures. The figures show one way of implementing the present invention and is not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.

Figure 1 shows an acoustic turbidity sensor according to one embodiment of the invention,

Figure 2 shows a cross section of an acoustic turbidity sensor,

Figure 3 illustrates the position of the transducers inside a housing of the acoustic turbidity sensor,

Figure 4 illustrates the fluid passage and measurement section of the flow part,

Figure 5 also shows the fluid passage and measurement section of the flow part,

Figure 6 shows an acoustic turbidity sensor device inserted into a flow pipe,

Figure 7 shows an acoustic turbidity sensor device provided with an insertion device, and

Figure 8 shown a cross section of the acoustic turbidity sensor device including the insertion device.

DETAILED DESCRIPTION OF AN EMBODIMENT

Referring to Fig. 1, a sensor device 1 comprising a flow part 2 and a probe 3 is shown. The sensor device is configured for measuring acoustic turbidity of a fluid flowing in a flow pipe 100 as shown in Fig. 6. The probe 3 is mounted on the flow part and adapted to be inserted into the flow pipe. When the probe is positioned in the flow pipe, fluid enters the probe via a probe inlet opening 34 and flows into the probe inlet channel 31. From the inlet channel the fluid flows through an inlet 22 in the flow part and into a fluid passage 21 of the flow part as shown in Fig. 5. The fluid passage extends between the inlet 22 and an outlet 23 in fluid communication with an outlet channel 33 of the probe. The fluid thus flow through the flow passage and back into the flow pipe via the probe outlet channel and a probe outlet opening 32. In the shown embodiment, the fluid passage 21 is provided as a channel milled into the flow part 2 and sealed off by a gasket 27 and a lid 29.

DK 2018 70652 A1

Part of the fluid passage connecting the inlet and outlet of the flow part constitutes a measurement section 24. Along the measuring section a sensor unit 7 is arranged to sense fluid flow and/or another fluid quality parameter of the flowing fluid. The sensor unit is arranged in the housing 5 and powered by a battery pack 55.

In the embodiment shown in Fig. 3, the fluid flowing through the measurement section is subjected to ultrasonic signals and based on these signals an acoustic turbidity of the fluid is determined. The sensor unit 7 includes three ultrasound transducers (51, 52) are arranged to send and receive ultrasound signal through the fluid flowing in the measurement section as seen from Fig. 3. The first and second ultrasound transducers 51 are arranged at opposite ends of the measurement section and a third ultrasound transducer 52 is arranged between the first and second ultrasound transducers.

The three transducers are part of a measurement circuit 54 operationally connected to a processing unit 53. The measurement circuit, exclusive of the transducers, and the processing unit are provided on a printed circuit board 56 arranged in a housing 5 provided in association with the flow part. In the shown embodiment, the housing 5 is mounted on the flow part using screws as seen from Fig. 5. Inside the housing a battery pack 55 is also provided for powering the processing unit and the measurement circuit. The housing may also be provided with a display opening or window allowing a display to be read.

The processing unit is configured for operating the ultrasound transducer to transmit and receive ultrasound signals through a fluid flowing in the measurement section. From the one or more received ultrasound signals, the measurement circuit and processing unit generate a digital signal indicative of the acoustic turbidity of the fluid. Based on digital signal, the processing unit determines a measure of the acoustic turbidity and stores this measure in a memory of the sensor device.

In one embodiment, the processing unit is configured to operate the first transducer and second transducers at a first frequency, when the transducers are used for measuring turbidity of the fluid. Additionally, the processing unit may be arranged to operate the first and second transducers at a second frequency with the purpose of measuring a flow rate of the fluid flowing in measurement section. Measuring the flow rate in addition to the signal indicative of the turbidity may improve the overall accuracy of the turbidity estimation.

DK 2018 70652 A1

The first frequency may be higher than the second frequency, such as the first frequency being the odd harmonic, like the third harmonic of the first frequency. The frequency difference allows for the flow rate to be measured at a reasonably low frequency, while measurements can be provided at a higher frequency to increase sensitivity to detect small particles in the fluid. Especially, the first frequency may be above 1 MHz, such as above 10 MHz, and the second frequency may be below 5 MHz, such as below 1 MHz.

Further details about how to determine the acoustic turbidity based on ultrasound signals is outside the scope of this application but may be found in the international patent application WO 2017/005268 by the applicant.

The sensor device further includes a wireless communication circuit including an antenna provided on the printed circuit board. Hereby, measures of acoustic turbidity determined by the processing unit may be transmitted to a remote reading device or though an advanced meter infrastructure for remote collection.

Referring to Fig. 3, the transducers are arranged in indentations 25 provided in the flow part communicating with the measurement section of the fluid passage. The transducers are kept in place by a holding plate 26 mounted on the flow part, e.g. by screw. Electrical connectors extend through the holding plate to connect the measurement circuit to electrodes on piezoelectric elements of the transducers. Fig. 4 and 5 illustrates the other side of the flow part providing the fluid passage 21 including the measurement section. Starting from the inlet 22 the fluid path has a substantially U-shaped extension with the fluid path being wider along the straight parallel sections than along the bend bottom section. In a measurement section a fluid conditioner 57 is inserted to reduce swivels and asymmetric flow profiles. Additionally, the fluid passage is connected to an air valve 28 provided in a upper face of the flow part 2. By operating the air valve it is possible to remove air trapped inside the fluid passage as trapped air may prevent circulation through the fluid passage.

Referring to Fig. 6, the probe of the sensor device is shown to be inserted into a pipe 100 through a fitting 45 mounted in an opening provided in the pipe wall. Instead of mounting the fitting directly in a pipe wall, the fitting may often be mounted in continuation of a ball valve or other valve mounted on the pipe. The fitting 45 includes an internal thread cooperating with an external thread of a compression nut 46 adapted to compress a compression ring or ferule 47 arranged

DK 2018 70652 A1 inside the fitting. Together these provide a compression fitting serving to lock the probe in position inside the pipe and provide a fluid tight seal against an external surface of the probe.

Now referring to Fig. 7 and 8, an embodiment of the sensor device comprising an insertion device 4 is shown. If the probe of the sensor device is arranged in or to be inserted into a pressurized vessel, such as a flow pipe, a certain force will act on the probe to force the probe out of the vessel/pipe. If the pressure in the vessel is moderate, the probe may be inserted manually by a force to the sensor device, e.g. by hand. However, if the pressure is higher, it may not be possible to manually insert the probe or at least the action will be associated with considerable risk. The same applies for a sensor device already installed, where unintentionally release of the compression fitting may result in the sensor device be shot out of the pressurized vessel.

To avoid such risks, the sensor device is provided with the insertion device. In the shown embodiment, the insertion device comprises four threaded cylinders cooperating to provide a telescopic mechanism adapted to pull the probe into the flow pipe by rotating the flow part and probe. In other embodiments the telescopic mechanism may comprise fever or more cooperating cylinders.

A first cylinder (41) of the insertion device is mountable in a fitting 45, corresponding to the fitting shown in Fig. 6, by a threaded nipple 411 provided in one end of the cylinder. Hereby, the insertion device may be secured to the flow pipe or other pressurized vessel provided with a fitting 45. The probe extends through the threaded nipple and into the hollow cylinders. The first cylinder is connected to a second intermediate cylinder having a smaller diameter than the first cylinder and an external thread cooperating with an internal thread of the first cylinder. Similar, the subsequent intermediate cylinder 42b has a smaller diameter than the cylinder 42a and an external and internal thread cooperating with corresponding internal and external threads, respectively, of the previous and following cylinders. The telescopic mechanism is terminated by a third cylinder 43 comprising and external thread cooperating with the internal thread of the second to last cylinder. The third cylinder 43 is secured to the probe and/or flow part whereby the insertion device fixates the sensor device to the fitting/flow pipe. By rotating the threaded cylinders in relation to one another the total length of the telescopic mechanism and thus the distance between the fitting mounted in a flow pipe the flow part be controlled. Hereby, the probe may be inserted into or retracted from the flow pipe to control the position of the probe inside the flow pipe. The internal and external threads may be single threads, double threads, triple threads or a thread of a higher order. In an alternative embodiment of the telescopic mechanism (not shown) the cylinders are

DK 2018 70652 A1 not provided with internal and external cooperating threads. Instead, the cylinders may be provided with internal and external cylindrical cams or traces configured to cooperate with mating cam followers provided on internal or external side of the adjacent cooperating cylinder, respectively. Hereby a functionality like that of threads may be achieved.

Like the compression nut described in connection with Fig. 6, the threaded nipple of the first cylinder may be screw into the fitting 45 to compress a ferule/compression ring 47, thereby fixating and preventing longitudinal displacement of the probe 3. During insertion or retraction of the sensor device, the threaded cylinders are mutually rotated to achieve the desired position of the probe inside the flow pipe. Subsequently, the first cylinder 41 is rotated to tighten the connecting between the threaded nipple 411 and the fitting 45 and thereby fixating the position of the probe.

Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms comprising or comprises do not exclude other possible elements or steps. Also, the mentioning of references such as a or an etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous.

Claims

1. A sensor device (1) arranged for measuring quality of water or another fluid flowing in a flow pipe (100), the sensor device comprising:

- a flow part (2) provided with a fluid passage (21) extending between an inlet (22) and outlet (23), wherein part of the fluid passage constitutes a measurement section (24);

- a sensor unit (7) arranged in a housing (5) provided in association with the flow part, the sensor being configured for sensing a fluid parameter, such as fluid flow or a fluid quality parameter, of a fluid in the measurement section;

- a battery pack (55) arranged in the housing for powering the sensor unit;

characterized in the sensor device further comprises a probe (3) mounted on the flow part for insertion into the flow pipe, the probe including an inlet channel (31) extending between a probe inlet opening (34) provided on one side of the probe and the inlet of the fluid passage and an outlet channel (33) extending between the outlet of the fluid channel and a probe outlet opening (32) provided on a side of the probe opposite the inlet opening.

2. The sensor device according to claim 1 being configured for measuring acoustic turbidity of a fluid flowing in the flow pipe, wherein:

- the sensor unit includes first and second ultrasound transducers (51) configured for transmitting and receiving ultrasonic signals through a fluid in the measurement section; and

- the sensor device further comprises a processing unit (53) operationally connected to a measurement circuit (54) arranged in the housing, the measurement circuit including the first and second ultrasound transducers and the processing unit being configured for operating the ultrasound transducer to generate a digital signal indicative of the acoustic turbidity of the fluid in response to one or more ultrasonic signals received by one of the ultrasound transducers.

3. The sensor device according to claim 1, wherein the probe outlet opening is larger than the probe inlet opening.

DK 2018 70652 A1

4. The sensor device according to any of the preceding claims, wherein the probe inlet opening and the probe outlet opening are provided at an end of the probe distal to the flow part.

5. The sensor device according to any of the preceding claims, wherein the sensor unit further comprises a third ultrasound transducer (52) included in the measurement circuit and arranged in the housing between the first and second ultrasound transducers; and wherein the processing unit is configured for operating the first and second transducers as transmitters and the third ultrasound transducer as a receiver; and the digital signal indicative of the acoustic turbidity is generated based on one or more signals received by one of the third ultrasound transducer.

6. The sensor device according to any of the preceding claims, further comprising an insertion device (4) for inserting the probe into a pressurized flow pipe, the insertion device including a plurality of cylinders cooperating to provide a telescopic mechanism adapted to pull the probe into the flow pipe by rotating the flow part and probe.

7. The sensor device according to claim 6, wherein the insertion device includes:

- a first cylinder (41) adapted for being mounted in a fitting (45) mountable on the flow pipe, the first cylinder including an internal thread,

- a second intermediary cylinder (42a) provided with an internal thread and an external thread cooperating with the internal thread of the first cylinder, and

- a third cylinder (43) secured to the probe and/or flow part and provided with an external thread cooperating with the internal thread of the second intermediary cylinder.