RU220371U1 - Wireless temperature sensor - Google Patents

Abstract

The utility model relates to the field of radio engineering and measurement technology; it can be used for remote temperature measurement via radio channel in multi-sensor monitoring systems to prevent emergency situations when monitoring the temperature of busbar connections of electrical cabinets, as well as for measuring the temperature of nuclear power plant facilities. Sensitive elements (SE) of temperature, made in the form of passive radio frequency SE, using the operating principle based on surface acoustic waves (SAW), which are insensitive to radiation. The technical result is to increase the reliability of the temperature measurement sensor. Contains a SAW-based SE (1) installed in a sealed housing (2), the terminals of which (3) are connected to a directional antenna (4) fixed through a dielectric spacer (6) on the base of a sensor (7) made of thermally conductive material. The sealed housing of the SE (2) is connected to the base of the sensor (7) by a thermal bridge (8) through heat-conducting paste (9). The SE (1) is made on a SAW delay line containing a piezoelectric substrate, on the surface of which an interdigitated transducer and at least three reflectors (reflectors) are applied. Moreover, its directional antenna is made on a printed circuit board (5) in the form of a microstrip antenna (4), the electrical resistance of which is the same along the entire length of its conductors. One ends of symmetrically located conductors (15) are soldered to two points of zero potential of the directional microstrip antenna (4) of the wireless sensor, which are brought out to the rear of the sensor. The other ends of the wires (15) are soldered to the washers (16) and (17), which are attached to the base (7) of the sensor with a screw (12). 4 salary f-ly, 9 ill.

Description

The utility model relates to the field of radio engineering and measurement technology; it can be used for remote temperature measurement via radio in multi-sensor systems for monitoring objects. Its use is relevant in systems for monitoring the condition of objects in order to prevent emergency situations when monitoring physical quantities, in particular temperature. In this case, measuring passive radio frequency elements are used as temperature sensitive elements, using the operating principle based on surface acoustic waves (SAW). Can be used to measure the temperature of nuclear power plant objects, since passive radio frequency elements using the surfactant-based operating principle are not sensitive to radiation.

The declared “Wireless temperature measurement sensor” hereinafter referred to as “sensor” (in the applicant’s technical documentation it is designated as a sensor under the code “Thermo-V”) is intended for integration into complete switchgears (Switchgear) operating voltages in the range from 0.4 to 110 kV for automating the processes of control (monitoring) of the temperature state of electrical buses and transmitting data to the automatic control system (ACS) of technological processes (TP) of the consumer, as well as for generating and transmitting warning and/or alarm signals.

The use of the claimed sensors, installed on the switchgear electrical buses and having thermal contact with them, allows for wireless, remote monitoring of the temperature at the point of their placement in real time. In this case, radio frequency identification of these wireless sensors occurs and data on the measured temperature is transmitted from them to the consumer’s automated process control system.

The use of the claimed sensors installed on the switchgear electrical buses and having thermal contact with them allows for wireless (remote) temperature monitoring at the point of their placement in real time. In this case, radio frequency identification of these wireless sensors occurs and data on the measured temperature is transmitted from them to the consumer’s automated process control system.

Devices and systems for controlling (monitoring) temperature for buses of electrical distribution systems are known, in which surfactant elements - RFID radio modules - are used to transmit temperature values, for example, according to the application for an invention of the Russian Federation: RU 2011150244 A dated 06/20/2013, IPC N02N 5/ 04 - [1]. The bus distribution system [1] includes a plurality of busbars, in the area where the sections connect, at least one temperature sensor is located, designed to record the temperature and make it possible to control it. Temperature sensors can be made in the form of resistive temperature sensors. Temperature sensors can be made in the form of radio modules with the possibility of individual addressing, and the radio modules themselves can be RFID radio modules.

The disadvantage of the known technical solution [1] is that in it the temperature is measured by resistive temperature sensors and additional adapter devices (systems) are required for communication with RFID radio modules (surfactant devices). In addition, the published technical solution [1] is difficult to implement due to insufficient design data.

Sensing elements based on surface acoustic waves for measuring temperature and their use in sensors and temperature control and monitoring systems are also widely known. For example, “a sensitive element on surface acoustic waves for measuring temperature” according to the patent for an invention of the Russian Federation: RU 2537751 C2 dated January 10, 2015, IPC G01K 11/22, H01L 41/08 - [2], consists of a plate of alpha- quartz, on the surface of which at least one interdigital transducer (IDT) and at least two reflective elements (RE) are formed. The IDT and OE electrodes are deviated from the Y1 axis by an angle not exceeding 20° in absolute value.

The disadvantage of the device [2] is that its use for determining the temperature of many closely located, for example, connections of current-carrying busbars, is difficult due to the occurrence of collisions when taking readings.

The applicant of this technical solution has his own identification and measuring devices (sensors) based on surfactants, which are protected by Russian Federation patents for utility models and inventions, the elements (features) of which are partially and/or fully practically implemented in the manufactured products of Avangard OJSC, namely:

“Radio tag” according to the utility model patent of the Russian Federation: RU 151943 U1 dated 04/20/2015, IPC H01Q 13/10 - [3];

“Device for radio frequency identification and positioning of railway transport” according to the patent for a utility model of the Russian Federation: RU 125535 U1 dated 03/10/2013, IPC B61L 25/00 - [4];

“Method of increasing the protective properties of an identification surfactant tag” according to the patent for an invention of the Russian Federation: RU 2608259 C2 dated January 17, 2017, IPC G06K 7/10, H04L 9/32 - [5];

“Passive sensor on surface acoustic waves” according to the patent for the invention of the Russian Federation: RU 2427943 C1 dated 08/27/2011, IPC H01L 41/08 - [6];

“A method for eliminating collisions in a set of sensors and a device for its implementation” according to the Russian invention patent: RU 2585911 C1 dated June 10, 2016, IPC G01D 5/48-[7];

“System for measuring the temperature of busbars of electrical cabinets” according to the patent for the invention of the Russian Federation: RU 2748868 C1 dated 06/01/2021, IPC G01K 11/26 - [8].

“Wireless sensor for measuring the temperature of busbars of electrical cabinets” according to the RF utility model patent of the applicant JSC Avangard: RU 204272 U1 dated 05/18/2021, IPC G01K 11/26 - [9].

The prototype of the claimed technical solution is the “Wireless sensor for measuring the temperature of the busbars of electrical cabinets” according to the patent for a utility model of the Russian Federation of the applicant JSC Avangard: RU 215141 U1 dated November 30, 2022, IPC G01K 11/26 - [10], which contains installed in a sealed housing a SAW sensitive element (SE), the terminals of which are connected to a directional (microstrip) antenna, fixed through a dielectric spacer on the base of a sensor made of thermally conductive material. The sealed housing of the SE is connected to the base of the sensor by a thermal bridge through heat-conducting paste. The SE is made on a SAW delay line containing a piezoelectric substrate, on the surface of which an interdigitated transducer and at least three reflectors (reflectors) are applied. Moreover, its directional antenna is made on a printed circuit board in the form of a microstrip antenna, the electrical resistance of which is the same along the entire length of its conductors.

A common disadvantage of the prototype [10], as well as analogues [1]-[9], is their low reliability, due to the fact that a static voltage potential (including high voltage) arises on the antenna, which leads to breakdown of the microcircuit ( sensitive element), and sensor failure.

The essence of the claimed technical solution is that the wireless temperature measurement sensor contains a SE installed in a sealed housing, the terminals of which are connected to a directional antenna fixed through a dielectric gasket on the base of the sensor made of thermally conductive material, and the sealed SE housing is connected to the base by a thermal bridge through thermally conductive paste sensor, the SE is made on a delay line on surface acoustic waves containing a piezoelectric substrate, on the surface of which an interdigitated transducer and at least three reflectors are applied, its directional antenna is made on a printed circuit board in the form of a microstrip antenna, the electrical resistance of which is along the entire length of its conductors the same. In this case, the zero potential points located on the directional (microstrip) antenna are connected by conductors (electrical potential equalization) to the mounting hardware of the sensor itself. In addition, the directional antenna of the wireless sensor can be made in the form of a microstrip antenna of the “slot” type, and its two points of zero potential, located at the edges of the “slot” of the microstrip antenna, are connected by symmetrical (in location) conductors to the mounting hardware of the sensor itself. Also, the directional antenna of a wireless sensor can be made in the form of a microstrip antenna of the “butterfly” type, and its two points of zero potential, located at the edges of the microstrip antenna, are connected by symmetrical (also in location) conductors to the mounting hardware of the sensor itself. Conductors (equalizing the electrical potential) can be soldered to the microstrip antenna at points of zero potential, and the other ends of the conductors are equipped with washers (soldered to the conductors) for connection using a threaded connection (with the mounting hardware of the sensor itself). Conductors for connecting the zero potential points of a microstrip antenna can be made in the form of a round wire with a diameter of 1-2 mm.

The essence of the claimed technical solution is further illustrated by the fact that on each microstrip antenna there are two points of zero potential, from which it is possible to discharge static voltage to the fittings on which the claimed sensor is mounted.

The use of conductors symmetrical in location relative to the directional microstrip antenna for connection to the mounting hardware of the sensor itself is necessary to minimize possible disturbances to the directional microstrip antenna itself.

The implementation of conductors to connect the points of zero potential of the microstrip antenna, to remove static voltage to the reinforcement on which the inventive sensor is mounted in the form of a round wire with a diameter of 1-2 mm is necessary to create structural rigidity of the sensor itself, and to prevent possible sagging and changes in the configuration of these wires. Making the wires round allows you to significantly simplify the design in view of the available range of round wires. The developed design uses round copper wires with a diameter of 1.5 mm. Reducing the diameter below 1 mm will lead to possible sagging of these wires, and increasing the diameter by more than 2 mm will lead to unnecessary consumption of material and weight of the meter.

The technical result of the claimed technical solution is to increase the reliability of the temperature measurement sensor.

The reliability of a wireless temperature measurement sensor is achieved by eliminating the occurrence of static voltage potential on the directional microstrip antenna, and, as a consequence, preventing breakdown of the sensitive element (microcircuit) and failure of the sensor.

The essence of the claimed technical solution is further illustrated by the following graphic materials:

In fig. 1 shows a view of a typical claimed wireless temperature measurement sensor with a section of the sensitive element.

In fig. 2 - view of a typical declared wireless temperature measurement sensor without a section of the SE.

In fig. 3 is a front view drawing of a wireless sensor with a stripe slot antenna on a printed circuit board.

In fig. 4 is a drawing of a rear view of a wireless sensor with a slot-type stripe antenna on a printed circuit board.

In fig. 5 - photo of the front of a wireless sensor with a slot-type strip antenna on a printed circuit board.

In fig. 6 - photo of the back of a wireless sensor with a slot-type strip antenna on a printed circuit board.

In fig. 7 - photograph from above of a wireless sensor with a slot-type strip antenna on a printed circuit board.

In fig. 8 - front photo of a wireless sensor with a stripe butterfly antenna on a printed circuit board.

In fig. 9 - photograph of wireless sensors installed on detachable connections of electrical buses with a strip antenna of the “slot” type on a printed circuit board.

In fig. 1-9 numbers indicate: 1 - sensitive element; 2 - sealed casing of the SE, made of material with high thermal conductivity (metal or ceramics); 3 - leads of the sealed housing (2) from the SE (1); 4 - directional antenna, made in the form of a directional microstrip antenna in a metallized layer of a printed circuit board made of textolite or ceramic), 5 - printed circuit board with an etched directional antenna (4); 6 - dielectric spacer for installing the antenna (4) with the SE (1) on the base of the sensor; 7 - sensor base, made of a profile-curved plate in the form of an angle made of metal material: copper, aluminum, steel, etc.; 8 - thermal bridge, for supplying heat from the controlled bus, through the base of the sensor (7) with the housing (2) of the sensitive element (1), the thermal bridge (8) can be made of either metal or heat-conducting ceramics, thermal bridge (8 ) is located inside a dielectric gasket (6), for example, ring-shaped; 9 - a layer of thermally conductive paste to improve heat transfer when supplying heat from the thermal bridge (8) to the body (2) of the sensitive element (1); 10 - screws securing the printed circuit board (5) through the dielectric gasket (6) to the base of the sensor (7); 11 - threaded bushings for fastening the printed circuit board (5) with screws (10) through a dielectric gasket (6) to the base of the sensor (7), which can be made of a profile-curved plate in the form of an angle or a more complex shape (for example, stepped); 12 - screw securing the thermal bridge (8) to the base (7) of the sensor; 13 - cutout of the base (7) of the sensor in the form of a fork for fastening the base (7) in the threaded connection of the current-carrying busbars; 14 - soldered conductor completely covered with solder; 15 - symmetrically located conductors for equalizing the electrical potential (static) between the points of zero potential of the directional (microstrip) antenna with the mounting hardware of the sensor itself; 16 and 17 - washers soldered to the other ends of the conductors (15) for connection using a threaded connection to the mounting hardware of the sensor itself; 18 - temperature-controlled contact connection of electrical busbars using threaded connecting elements.

The sensor for remote measurement of the temperature of the busbars of electrical cabinets contains a SE (1) made on a delay line on a surfactant containing a piezoelectric substrate, on the surface of which an interdigital converter (IDT) and at least three reflectors are applied, offset at different distances relative to the IDT, the first reflector has the shortest delay time, the second reflector is located in the middle part of the surface of the piezoelectric substrate, the third reflector is located at the end of the piezoelectric substrate, such that their relative position determines the reference delay time of the surfactant. In this case, the SE (1) is installed in a sealed housing (2) made of heat-conducting material. The IDT SE (1) is connected by leads (3), for example, by soldering or welding to a directional antenna (4). The directional antenna (4) can be made in the form of a microstrip antenna in a metallized layer of a printed circuit board (5) made of textolite or ceramic. The printed circuit board (5) (with directional antenna (4)) is secured with screws (10) through a dielectric spacer (6) to the base (7) using threaded bushings (11), which are inserted into the holes in the base (7). The dielectric spacer (6) can be made in the form of a ring, inside of which a sealed casing (2) of the SE (1) is placed. In turn, the dielectric gasket (6) is secured with threaded bushings (11) and screws (10) to the thermally conductive base (7) of the sensor. The sealed housing (2) of the SE (1) with the side opposite to the terminals (3) is pressed through a heat-conducting paste (9) to the thermal bridge (8), which in turn is secured with a screw (12) to the base (7) of the sensor for supplying heat from the controlled threaded connections (15) of electrical buses. The gap between the sealed housing (2) of the SE (1) and the thermal bridge (8) can be filled with heat-conducting paste KPT-8 GOST 19783-74. The base (7) of the sensor, with its cutout (13) in the form of a fork, is fixed in a controlled threaded connection of the electrical busbars (15). The directional antenna (4) of the sensor can be made in the form of a microstrip antenna of the “slot” type, shown in figures 1, 2, 3, 4, 5, 6, 7 and 9, or of the “butterfly” type, shown in figure (8). The base (7) of the sensor made of thermally conductive material can be made of a metal profile curved plate (7), for example, in the form of a corner. As a thermal bridge (8) between the outer surface of the sealed housing (2) of the SE (1) and the base (7) or (17) of the sensor through the thickness of the dielectric spacer (6), a solid washer made of a thermally conductive material (for example, copper or aluminum). The thermal bridge (8) is fixed on the very base (7) of the sensor, and its thickness depends on the thickness of the dielectric spacer (6) and the height of the sealed housing (2) of the SE (1). The thickness of the thermal bridge (8) is selected individually, for example, by removing a layer of metal from its flat surface. The dielectric spacer (6) is necessary to create a guaranteed required gap between the antenna (3) and the base (7) of the sensor, the size of which depends on the operating frequency range of the device. In this case, the directional antenna (4) is made on a printed circuit board (5) in the form of a microstrip antenna (4), the electrical resistance of which is the same along the entire length of its conductors. In the places where the conductors narrow (in the narrowed conductors) of the microstrip antenna (4) of the printed circuit board (5), a conductor is soldered onto it, which is completely covered with a layer of solder (14). As solder, POS-61 solder GOST 21931-76 can be used. The soldered conductor (not shown under the solder layer in the figures) is made of the material of the conductive layer of the printed circuit board (5), usually copper, and its cross-sectional area is inversely proportional to the reduction in cross-sectional area in the narrowing of the conductors (in the narrowed conductors) of the printed circuit board (5) microstrip antenna (4). The directional microstrip antenna (4) of the wireless sensor has two points of zero potential, to which one ends of symmetrically located conductors (15) are soldered, which are brought out to the rear of the sensor. The other ends of the wires (15) are soldered to the washers (16) and (17), which are attached to the base (7) of the sensor with a screw (12). Through the wires (15), the static electric potential is equalized between the zero potential points of the directional microstrip antenna (4) through the base of the sensor (7) with the mounting hardware of the sensor itself, namely a temperature-controlled contact connection of the electrical busbars (18) using threaded connecting elements.

The operation of the claimed device is as follows.

When the reader's radio signal acts on the IDT SE (1), due to the inverse piezoelectric effect, the electromagnetic oscillation is converted into an acoustic wave, which propagates along the surface of the piezoelectric substrate made on the SAW delay line. After which the acoustic wave is reflected from the corresponding reflectors and returns back to the IDT, where due to the direct piezoelectric effect the acoustic wave is converted into an electromagnetic one. Reflectors (electrodes, reflectors) are applied to the piezoelectric substrate plate, which can be made in the form of strips or grooves. When the temperature of the piezoelectric substrate plate changes as a result of linear expansion and compression, its geometric dimensions change, the phase velocity of surfactant propagation changes, and the distance between the reflectors also changes. The temperature movements of reflectors range from units to hundreds of nanometers, but at a high frequency of the irradiating signal, for example, 2.45 GHz, the phase shift when reflecting surfactants from the reflectors can be measured (estimated). Analysis of the phase shift of signal responses from SAW reflectors allows us to determine these movements with a high degree of resolution (at a high frequency of the irradiating signal of 2.45 GHz) and, taking into account the linear expansion coefficient for a given substrate material, obtain both the value of temperature changes and the value of the absolute temperature of the substrate after calibrating the device over the entire operating temperature range.

At the same time, the claimed device has increased operational reliability, due to the fact that the occurrence on the directional microstrip antenna (on its surface (4), relative to the thermal bridge (8) connected through the base of the sensor (7) with the controlled contact connection of the electrical buses (18) is excluded. )) static voltage potential. This, in turn, prevents electrical breakdown of the sensitive element located in the housing (microcircuit) and failure of the sensor.

The declared “Wireless temperature measurement sensor”, together with the restrictive and distinctive features of the utility model formula, is new to well-known sensor devices with temperature sensitive elements based on passive radio frequency surfactant elements. With a group of declared wireless sensors, reliable control of the temperature of the electrical connections of the switchgear buses is ensured over the entire range of temperature changes, and also ensures guaranteed identification of a specific installed sensor (without collisions). In this regard, this technical solution meets the “novelty” criterion.

The implementation of the claimed sensor was carried out by the applicant and is undergoing trial operation, which is presented in graphic materials: photographs in Fig. 5, 6, 7, 8 and 9, which implies compliance with the “industrial applicability” criterion.

Literature

1. Application for an invention of the Russian Federation: RU 2011150244 A dated 06/20/2013, IPC N02N 5/04, “Temperature control for a bus distribution system.”

2. Patent for invention of the Russian Federation: RU 2537751 C2 dated January 10, 2015, IPC G01K 11/22, H01L 41/08, “Sensing element on surface acoustic waves for measuring temperature.”

3. RF utility model patent: RU 151943 U1 dated 04/20/2015, IPC H01Q 13/10, “Radio Tag”.

4. RF utility model patent: RU 125535 U1 dated March 10, 2013, IPC B61L 25/00, “Radio frequency identification and positioning device for railway transport.”

5. Patent for invention of the Russian Federation: RU 2608259 C2 dated January 17, 2017, IPC G06K 7/10, H04L 9/32, “Method for increasing the protective properties of an identification surfactant tag.”

6. Patent for invention of the Russian Federation: RU 2427943 C1 dated August 27, 2011, IPC H01L 41/08, “Passive sensor on surface acoustic waves.”

7. Patent for invention of the Russian Federation: RU 2585911 C1 dated June 10, 2016, IPC G01D 5/48, “Method for eliminating collisions in a set of sensors and a device for its implementation.”

8. Patent for invention of the Russian Federation: RU 2748868 C1 dated 06/01/2021, IPC G01K 11/26, “System for measuring the temperature of busbars of electrical cabinets.”

9. RF utility model patent: RU 204272 U1 dated 05/18/2021, IPC G01K 11/26, “Wireless sensor for measuring the temperature of electrical cabinet buses.”

10. RF utility model patent: RU 215141 U1 dated November 30, 2022, IPC G01K 11/26, “Wireless sensor for measuring the temperature of electrical cabinet buses” - prototype.

Claims (5)

1. A wireless temperature measurement sensor containing a sensing element installed in a sealed housing, the terminals of which are connected to a directional antenna fixed through a dielectric gasket on the base of the sensor made of thermally conductive material, and the sealed housing of the sensing element is connected to the base of the sensor by a thermal bridge through thermal conductive paste, the sensing element made on a delay line on surface acoustic waves containing a piezoelectric substrate, on the surface of which an interdigitated transducer and at least three reflectors are applied, its directional antenna is made on a printed circuit board in the form of a microstrip antenna, the electrical resistance of which is the same along the entire length of its conductors, differing in that the zero potential points located on the microstrip antenna are connected by conductors to the mounting hardware of the sensor itself. 2. The wireless sensor according to claim 1, characterized in that its directional antenna is made in the form of a microstrip antenna of the “slot” type, and its two points of zero potential, located at the edges of the “slot” of the microstrip antenna, are connected by symmetrical conductors to the mounting hardware of the sensor itself . 3. The wireless sensor according to claim 1, characterized in that its directional antenna is made in the form of a microstrip antenna of the “butterfly” type, and its two points of zero potential, located at the edges of the microstrip antenna, are connected by symmetrical conductors to the mounting hardware of the sensor itself. 4. Wireless sensor according to claim 1, characterized in that on the microstrip antenna at the points of zero potential the conductors are soldered, and the other ends of the conductors are equipped with a washer for connection using a threaded connection. 5. The wireless sensor according to claim 1, characterized in that its conductors for connecting the zero potential points of the microstrip antenna are made in the form of a round wire with a diameter of 1-2 mm.