AU2020101230A4 - A Hot Wire Tester Suitable for Rotating Conditions - Google Patents

A Hot Wire Tester Suitable for Rotating Conditions Download PDF

Info

Publication number
AU2020101230A4
AU2020101230A4 AU2020101230A AU2020101230A AU2020101230A4 AU 2020101230 A4 AU2020101230 A4 AU 2020101230A4 AU 2020101230 A AU2020101230 A AU 2020101230A AU 2020101230 A AU2020101230 A AU 2020101230A AU 2020101230 A4 AU2020101230 A4 AU 2020101230A4
Authority
AU
Australia
Prior art keywords
fluid
hot wire
rotor
velocity
module
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
AU2020101230A
Inventor
Wen Guo
Weina HUANG
Haiwang LI
Zhi TAO
Ruquan YOU
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Beihang University
Original Assignee
Beihang University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Beihang University filed Critical Beihang University
Priority to AU2020101230A priority Critical patent/AU2020101230A4/en
Application granted granted Critical
Publication of AU2020101230A4 publication Critical patent/AU2020101230A4/en
Ceased legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P5/00—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
    • G01P5/10—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring thermal variables
    • G01P5/12—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring thermal variables using variation of resistance of a heated conductor
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
    • G01P3/42—Devices characterised by the use of electric or magnetic means
    • G01P3/44—Devices characterised by the use of electric or magnetic means for measuring angular speed
    • G—PHYSICS
    • G08—SIGNALLING
    • G08C—TRANSMISSION SYSTEMS FOR MEASURED VALUES, CONTROL OR SIMILAR SIGNALS
    • G08C19/00—Electric signal transmission systems
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R39/00—Rotary current collectors, distributors or interrupters
    • H01R39/02—Details for dynamo electric machines
    • H01R39/34—Connections of conductor to slip-ring
    • G—PHYSICS
    • G08—SIGNALLING
    • G08C—TRANSMISSION SYSTEMS FOR MEASURED VALUES, CONTROL OR SIMILAR SIGNALS
    • G08C2200/00—Transmission systems for measured values, control or similar signals
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M1/00—Analogue/digital conversion; Digital/analogue conversion
    • H03M1/001—Analogue/digital/analogue conversion

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Arrangements For Transmission Of Measured Signals (AREA)

Abstract

of Description The embodiments of the present invention disclose a hot wire tester suitable for rotating conditions, which comprises a rotor-stator conversion device, a rotating end and a data receiver. When measuring the velocity of the turbulent boundary layer of the test fluid, the rotating end rotates with the fluid to be tested. Electrical signals related to the velocity of the turbulent boundary layer of the test fluid are collected in real time and transmitted to the data receiver through the rotor-stator conversion device. Compared with the existing devices that can only measure the velocity of the fluid in the static state, the device has a rotating end which can rotate with the fluid to be tested, which realizes the measurement of the velocity of the turbulent boundary layer of the fluid in the rotating state. In addition, in the transmission of electrical signals through the rotor-stator conversion device, A/D conversion module is introduced to convert analog signals into digital signals and then transmit them to the conductive slip ring, thus reducing the signal interference caused by the rotation of the slip ring. Drawings of Description 11102 103 FIG.1I CI~orieA-l1og &gmal AD Cnvg¶oldmtive Slip R,4 mmig Hot Wife Pfobe Mr~dpehodue - - - - - - - - I Rotating End Rotor-statof Comvemon evice FIG. 2 1/1

Description

Drawings of Description
11102 103
FIG.1I
CI~orieA-l1og &gmal AD Cnvg¶oldmtive Slip R,4 mmig Hot Wife Pfobe Mr~dpehodue
- - - - - - - - I
Rotating End Rotor-statof Comvemon evice
FIG. 2
1/1
Description
A Hot Wire Tester Suitable for Rotating Conditions
Technical Field The invention belongs to the technical field of velocity measurement, in particular to a hot wire tester suitable for rotating conditions.
Technical Background In the study of the turbulent boundary layer of rotating machinery, velocity measurement has always been a difficult subject. To study the turbulent flow in the boundary layer, the velocity in the turbulent boundary layer needs to be measured. Hot wire anemometer is a widely used velocity measurement technology, especially for the measurement of velocity in the boundary layer, with high time resolution and test frequency. It is of great significance to analyze the turbulent flow in the boundary layer. However, the conventional hot wire test system (CTA) is not suitable for measuring the velocity in the rotating state. Meanwhile, a Wheatstone bridge is adopted in hot-wire anemometer to output analog signals, but the transmission stability of wireless signals is poor. If slip ring is used to realize the rotor-stator conversion, the output signals will be interfered.
In the process of realizing the embodiment of the invention, the inventor found that the existing hot-wire testers could not measure the velocity of the fluid in the rotating state, and the accuracy and stability of the signals could not be guaranteed in the process of using the slip ring to realize the rotor-stator conversion.
Invention Summary The technical problem to be solved by the invention is how to solve the problem that the existing hot-wire tester cannot measure the velocity of the fluid in the rotating state, and the accuracy and stability of the signals cannot be guaranteed in the process of using the slip ring to realize the rotor-stator conversion.
In view of the above problems, the embodiment of the present invention provides a hot wire tester suitable for rotating conditions, which comprises a rotor-stator conversion device, a rotating end that rotates with the fluid to be tested during the test and a static data receiver.
The rotor-stator conversion device connects the rotating end and the data receiver;
The rotating end transmits the electrical signals generated during the rotation of the fluid to be tested to the rotor-stator conversion device, and the rotor-stator conversion device transmits the electrical signals to the data receiver, and the data receiver stores the electrical signals.
Optionally, the rotor-stator conversion device is a conductive slip ring;
The output end of the rotating end is connected to the end where the rotor of the conductive slip ring is located, and the data receiver is connected to the end where the stator of the conductive slip ring is located.
Optionally, the rotating end comprises hot wire probe, CTA module and A/D conversion module;
The hot wire probe is connected to the input end of the CTA module, and the output end of the CTA module is connected to the input end of the A/D conversion module;
The output end of the A/D conversion module is connected to the conductive slip ring;
When measuring the velocity of the turbulent boundary layer of the fluid to be tested, the hot wire probe is placed in the fluid to be tested; the CTA module is used to measure the electrical signals on the hot wire probe, and transmit the electrical signals to the A/D conversion module; the A/D conversion module converts the electrical signals into digital signals, and transmits the digital signals to the conductive slip ring.
Optionally, the CTA module includes a Wheatstone bridge.
Optionally, the data receiver is also used to convert the digital signals into the velocity of the turbulent boundary layer of the fluid to be tested according to the pre-stored correspondence between the digital signals and the velocity of the turbulent boundary layer.
Optionally, it also includes a display module;
The display module is used to display the velocity of the turbulent boundary layer of the fluid to be tested.
Optionally, the size of the CTA module is 70 mmx40 mmx20 mm; the size of the A/D conversion module is 50 mmx60 mmx15 mm.
The embodiments of the present invention provide a hot wire tester suitable for rotating conditions, which comprises a rotor-stator conversion device, a rotating end and a data receiver. When measuring the velocity of the turbulent boundary layer of the test fluid, the rotating end rotates with the fluid to be tested. Electrical signals related to the velocity of the turbulent boundary layer of the test fluid are collected in real time and transmitted to the data receiver through the rotor-stator conversion device. Compared with the existing devices that can only measure the velocity of the fluid in the static state, the device has a rotating end which can rotate with the fluid to be tested, which realizes the measurement of the velocity of the turbulent boundary layer of the fluid in the rotating state. In addition, in the transmission of electrical signals through the rotor-stator conversion device, A/D conversion module is introduced to convert analog signals into digital signals and then transmit them to the conductive slip ring, thus reducing the signal interference caused by the rotation of the slip ring.
Brief Description of the Drawings In order to explain more clearly the embodiments in the present invention or the technical solutions in the prior art, the following will briefly introduce the figures needed in the description of the embodiments or the prior art. Obviously, figures in the following description are only some embodiments of the present invention, and for a person skilled in the art, other figures may also be obtained based on these figures without paying any creative effort.
FIG. 1 is the schematic diagram of the hot wire tester suitable for rotating conditions provided in an embodiment of the present invention.
FIG. 2 is the schematic diagram of the hot wire tester suitable for rotating conditions provided in another embodiment of the present invention.
Detailed Description of the Presently Preferred Embodiments To make the purposes, technical schemes and advantages of the present invention clearer, the technical solution in the embodiments of the present invention will be described below clearly and completely with reference to the drawings of the embodiments of the present invention; obviously, the described embodiments are only part rather than all of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of the present invention.
FIG. 1 is the schematic diagram of the hot wire tester suitable for rotating conditions provided in an embodiment of the present invention. As shown in FIG. 1, the device comprises a rotor-stator conversion device 102, a rotating end 101 that rotates with the fluid to be tested during the test and a static data receiver 103.
The rotor-stator conversion device 102 connects the rotating end 101 and the data receiver 103;
The rotating end 101 transmits the electrical signals generated during the rotation of the test fluid to the rotor-stator conversion device 102, and the rotor-stator conversion device 102 transmits the electrical signals to the data receiver 103, and the data receiver 103 stores the electrical signals.
It should be noted that the hot wire tester provided in this embodiment is mainly used to test the velocity of the fluid in the rotating state. Compared with the devices that can only test the fluid in the static state, the hot wire tester provided in this embodiment has a rotating end which rotates with the fluid, which avoids the influence of the rotation of the fluid itself on the test result.
It is understandable that since the rotating end of the hot wire tester provided in this embodiment rotates with the fluid to be tested during the test, and the data receiver for receiving data is in the static state, then the rotor-stator conversion device connecting the rotating end and the data receiver needs to realize "rotor-stator conversion", so that the rotation of the rotating end has no influence on the static data receiver. For example, a conductive slip ring can be used as the rotor-stator conversion device, so as to achieve a normal connection with the conductive slip ring during the rotation of the rotating end and ensure data transmission. Certainly, devices that can realize the "rotor-stator conversion" so that the rotation of the rotating end has no influence on the static data receiver can all be used as the rotor-stator conversion device, which is not limited in this embodiment.
The fluid to be tested may be a liquid or a gas, which is not limited in this embodiment.
The embodiments of the present invention provide a hot wire tester suitable for rotating conditions, which comprises a rotor-stator conversion device, a rotating end and a data receiver. When measuring the velocity of the turbulent boundary layer of the test fluid, the rotating end rotates with the fluid to be tested. Electrical signals related to the velocity of the turbulent boundary layer of the test fluid are collected in real time and transmitted to the data receiver through the rotor-stator conversion device. Compared with the existing devices that can only measure the velocity of the fluid in the static state, the device has a rotating end which can rotate with the fluid to be tested, which realizes the measurement of the velocity of the turbulent boundary layer of the fluid in the rotating state. In addition, in the transmission of electrical signals through the rotor-stator conversion device, A/D conversion module is introduced to convert analog signals into digital signals and then transmit them to the conductive slip ring, thus reducing the signal interference caused by the rotation of the slip ring.
Further, on the basis of the above embodiments, the rotor-stator conversion device is a conductive slip ring;
The output end of the A/D conversion module is connected to the end where the rotor of the conductive slip ring is located, and the data receiver is connected to the end where the stator of the conductive slip ring is located.
In this embodiment, a conductive slip ring is used as the rotor-stator conversion device connecting the rotating end and the data receiver. The rotating end is connected to the end where the conductive slip ring rotor is located, and the rotor-stator conversion device is connected to the end where the conductive slip ring stator is located, which ensures that the rotation of the rotating end does not affect the data receiver and realizes the signal transmission from the rotating end to the data receiver.
Further, on the basis of the above embodiments, as shown in FIG. 2, the rotating end of the hot wire tester comprises hot wire probe, CTA module, and A/D conversion module;
The hot wire probe is connected to the input end of the CTA module, and the output end of the CTA module is connected to the input end of the A/D conversion module;
The output end of the A/D conversion module is connected to the conductive slip ring;
When measuring the velocity of the turbulent boundary layer of the test fluid, the hot wire probe is placed in the fluid; the CTA module is used to measure the electrical signals on the hot wire probe, and transmit the electrical signals to the A/D conversion module; the A/D conversion module converts the electrical signals into digital signals, and transmits the digital signals to the conductive slip ring.
Further, a circuit is included between the CTA module and the A/D conversion module for analog signal preprocessing of the electrical signals output by the CTA module.
It should be noted that the A/D conversion module is used to convert analog signals to digital signals. In the process of testing the fluid, if the analog signals are directly transmitted to the data receiver through the conductive slip ring, the instability of the analog signals will affect the test result. In order to improve the stability of signal transmission and the accuracy of testing the fluid, in this embodiment, the analog signals are converted into digital signals before signal transmission. This signal transmission method reduces the signal interference caused by the rotation of the slip ring, and ensures the accuracy and stability of the signals in the process of the rotor-stator conversion of the conductive slip ring.
It should be noted that the hot wire probe is in direct contact with the fluid to be tested in the process of testing the fluid. The CTA module is used to collect changes in the electrical signals caused by the test fluid flowing through the hot wire probe. It is understandable that the electrical signals collected by the CTA module are analog signals.
The CTA module can directly transfer the collected analog signals to the A/D conversion module, or it can preprocess the analog signals before transmitting them to the A/D conversion module.
This embodiment provides a hot wire tester suitable for rotating conditions. A/D conversion module is provided at the rotating end to convert the electrical signals collected by the CTA module into digital signals, and then transmit them to the data receiver through the conductive slip ring, which reduces the signal interference caused by the rotation of the slip ring, ensures the stability of the signal transmission process, and improves the accuracy of the velocity measurement of the test fluid.
Further, on the basis of the above embodiments, the CTA module includes a Wheatstone bridge.
It should be noted that the CTA module is integrated, which comprises a Wheatstone bridge, and some modulation circuits. Its function is to amplify the signal of hot wire probe without having errors.
In the hot wire tester suitable for rotating conditions provided in this embodiment, the CTA module at least includes a Wheatstone bridge, through which the electrical signals on the hot wire probe are collected. Of course, the CTA module may also include some modulation circuits or amplification circuits to amplify and optimize the electrical signals collected through the Wheatstone bridge.
Further, on the basis of the above embodiments, the data receiver is also used to convert the digital signals into the velocity of the turbulent boundary layer of the fluid to be tested according to the pre-stored correspondence between the digital signals and the velocity of the turbulent boundary layer.
As shown in FIG. 2, the data receiver may be a computer, which can store digital signals and convert the digital signals into corresponding velocity signals.
Specifically, the correspondence between the digital signal and the velocity of the turbulent boundary layer is pre-stored in the computer, for example, the mapping table of the digital signal and the velocity of the turbulent boundary layer. When the data receiver receives the digital signals, the velocity of turbulent boundary layer corresponding to each digital signal is found according to the mapping table, so as to realize the conversion between the digital signal and the velocity of turbulent boundary layer.
Wherein, the mapping table is obtained by means of calibration. Specifically, put the hot wire probe in a wind tunnel with a known velocity, measure the voltage or current, and then obtain the calibration curve of the voltage or current vs velocity.
In the actual measurement process, the digital signals obtained are related to voltage or current, which are substituted into the calibration curve of voltage or current vs velocity to obtain the velocity curve of turbulent boundary layer.
Further, on the basis of the above embodiments, it also includes a display module;
The display module is used to display the velocity of the turbulent boundary layer of the fluid to be tested.
It is understandable that the above data receiver and display module may be the computer shown in FIG. 2. Through this computer, the user can control the displayed results. For example, the user may choose to display the velocity of the turbulent boundary layer of the fluid to be tested in the form of a table or a graph, which is not restricted in this embodiment.
The data receiver and the display module provided in this embodiment can realize the conversion and display between the collected electrical signals and the velocity values, which ensures that the user can obtain the velocity of the turbulent boundary layer of the test fluid in a timely and accurate manner.
Further, on the basis of the above embodiments, the size of the CTA module is 70 mmx40 mmx20 mm; the size of the A/D conversion module is 50 mmx60 mmxl5 mm.
The devices that can only measure the velocity of the fluid in the static state are approximately 50 cm x 50 cm x 15 cm in size. The hot wire tester suitable for rotating conditions provided in this embodiment may control the dimensions of each module. For example, the size (length, width, height) of the CTA module is mmx4mmx2mm, and the size of the A/D conversion module (length, width, height) is 50mmx6mmx15mm, so that the size of the rotating end is smaller, avoiding the excessive load on the equipment carrying the fluid to be tested during the rotation of the rotating end with the fluid to be tested, and ensuring that the velocity of the turbulent boundary layer of the test fluid is measured without affecting the rotation of the test fluid.
Compared with the prior art, the hot wire tester suitable for rotating conditions provided in the embodiments of the present invention can measure the velocity of the turbulent boundary layer in the rotating state; the rotating test system is miniaturized, modularized, and easy to install and use; the signals converted by A/D conversion module can be subjected to rotor-stator conversion through USB conductive slip ring, with strong anti-interference ability.
Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than limit the scope thereof. The above embodiments can be modified by those with ordinary skill in the art without departing from the scope of the present invention as defined in the following appended claims.

Claims (7)

Claims
1. A hot wire tester suitable for rotating conditions is characterized in the fact that it comprises a rotor-stator conversion device, a rotating end that rotates with the fluid to be tested during the test and a static data receiver.
The rotor-stator conversion device connects the rotating end and the data receiver;
The rotating end transmits the electrical signals generated during the rotation of the fluid to be tested to the rotor-stator conversion device, and the rotor-stator conversion device transmits the electrical signals to the data receiver, and the data receiver stores the electrical signals.
2. The hot wire tester according to claim 1 is characterized in the fact that the rotor-stator conversion device is a conductive slip ring;
The output end of the rotating end is connected to the end where the rotor of the conductive slip ring is located, and the data receiver is connected to the end where the stator of the conductive slip ring is located.
3. The hot wire tester according to claim 2 is characterized in the fact that the rotating end comprises hot wire probe, CTA module and A/D conversion module;
The hot wire probe is connected to the input end of the CTA module, and the output end of the CTA module is connected to the input end of the A/D conversion module;
The output end of the A/D conversion module is connected to the conductive slip ring;
When measuring the velocity of the turbulent boundary layer of the fluid to be tested, the hot wire probe is placed in the fluid to be tested; the CTA module is used to measure the electrical signals on the hot wire probe, and transmit the electrical signals to the A/D conversion module; the A/D conversion module converts the electrical signals into digital signals, and transmits the digital signals to the conductive slip ring.
4. The hot wire tester according to claim 2 is characterized in the fact that the CTA module comprises a Wheatstone bridge.
5. The hot wire tester according to claim 1 is characterized in the fact that the data receiver is also used to convert the digital signals into the velocity of the turbulent boundary layer of the fluid to be tested according to the correspondence between the pre-stored digital signals and the velocity of the turbulent boundary layer.
6. The hot wire tester according to claim 5 is characterized in the fact that it also includes a display module.
The display module is used to display the velocity of the turbulent boundary layer of the fluid to be tested.
7. The hot wire tester according to claim 3 is characterized in the fact that the size of the CTA module is 70 mmx40 mmx20 mm; the size of the A/D conversion module is 50 mmx60 mmx15 mm.
AU2020101230A 2020-07-02 2020-07-02 A Hot Wire Tester Suitable for Rotating Conditions Ceased AU2020101230A4 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2020101230A AU2020101230A4 (en) 2020-07-02 2020-07-02 A Hot Wire Tester Suitable for Rotating Conditions

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AU2020101230A AU2020101230A4 (en) 2020-07-02 2020-07-02 A Hot Wire Tester Suitable for Rotating Conditions

Publications (1)

Publication Number Publication Date
AU2020101230A4 true AU2020101230A4 (en) 2020-08-06

Family

ID=71833577

Family Applications (1)

Application Number Title Priority Date Filing Date
AU2020101230A Ceased AU2020101230A4 (en) 2020-07-02 2020-07-02 A Hot Wire Tester Suitable for Rotating Conditions

Country Status (1)

Country Link
AU (1) AU2020101230A4 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114624464A (en) * 2022-03-23 2022-06-14 北京航空航天大学 Non-contact hot film testing equipment and method for judging stability of rotor part of gas compressor

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114624464A (en) * 2022-03-23 2022-06-14 北京航空航天大学 Non-contact hot film testing equipment and method for judging stability of rotor part of gas compressor

Similar Documents

Publication Publication Date Title
CN101692097A (en) Anemoclinograph wind meter
AU2020101230A4 (en) A Hot Wire Tester Suitable for Rotating Conditions
US9780833B2 (en) De-embedding cable effect for waveform monitoring for arbitrary waveform and function generator
CN112098916A (en) System and method for superposing ripples on direct current loop in direct current electric energy detection device
CN107271714A (en) A kind of hot line test equipment being applied under rotating condition
JP2009276354A (en) Current-measuring device and current measurement method
CN106645590B (en) Gas concentration measuring device based on differential acquisition
KR100538081B1 (en) Lightning arrester analyzer and analyzing method
JPS61126485A (en) Error measuring instrument
CN111948445A (en) Power measurement circuit, method and device
KR100366397B1 (en) Automatic measuring and assessment system for bridge diagnostics
CN109085782A (en) Visualize aerodynamic parameter acquisition system
CN211577246U (en) Device for collecting waveform of current transformer
CN2556655Y (en) Atmospheric turbulance sounding device
CN104019869B (en) The wireless automatic calibrator of fuel charger capacity of vacuum heat-preserving standard capacity measure
CN106353643A (en) Resistance proportion cable fault tester
KR100307011B1 (en) Digital measurement device having remote control function using internet and controlling method thereof
McConnell et al. Data acquisition
WO2021082532A1 (en) Test system and test method for intelligent electricity meter
CN116256103A (en) Tunnel wind pressure detection device and method
CN105068005B (en) The detecting system and detection method of PG motors
CN219574243U (en) High-resistance fault loop resistance precision measurement circuit for railway signal cable
CN104155025B (en) The system for detecting temperature of Low Temperature Liquid medium and temperature transmitter
CN114594277B (en) Test method based on rotary hot film equipment and application thereof
CN209570216U (en) Facilitate the transmitter of the two-wire system loop power supply of test, maintenance

Legal Events

Date Code Title Description
FGI Letters patent sealed or granted (innovation patent)
MK22 Patent ceased section 143a(d), or expired - non payment of renewal fee or expiry