AU2018101805A4

AU2018101805A4 - The smart electromechanical volume and level meter for fluids using encoder sensor

Info

Publication number: AU2018101805A4
Application number: AU2018101805A
Authority: AU
Inventors: Maryam Hedayati; Mehdi Korki; Morteza Tahmasbi
Original assignee: Hedayati Maryam Mrs
Current assignee: Hedayati Maryam Mrs
Priority date: 2018-11-24
Filing date: 2018-11-24
Publication date: 2019-01-03
Anticipated expiration: 2026-11-24

Abstract

Abstract The electromechanical volume and level meter for fluids using encoders consists of four parts: mechanical part, encoder sensor part, control and management part, and smart calibration and error diagnostic part. The mechanical part is mainly a floating part. When the level of fluid in the tank increases or decrease, the floating part (Fig. 1 and Fig. 2) goes up or down and because it is attached and fixed to the chain, it pulls the chain up or down and rotates the chain wheel clockwise or counter clockwise. Hence, the reciprocating motion is converted to rotary motion. Rotary motion of chain wheel, rotates the shaft of the chain wheel (Fig. 5) and this shaft is connected to the encoder sensor part through a coupling part. Hence, the rotary motion of the chain wheel is converted to electronic pulses via encoder sensor and the generated pulses are transmitted to the electronic board (which is the main component of the control and management part) to calculate these rotations. This level meter has three other sensors: minimum sensor, calibration sensor, and overflow sensor. The zero and one-pulse signals of these sensors are sent to the electronic board for fluid level calculations. These sensors are used to identify the encoder error, checking the accuracy of the encoder calculations and also identify the failure of minimum, calibration and overflow sensors. If the level meter device becomes out of calibration and its accuracy decreases, when the level of the fluid reaches to each of the abovementioned sensors, it automatically calibrates the device and the fluid level calculations will be performed with high accuracy. That is, every time the tank depletes and fills up, level meter is automatically calibrated 6 times. The level meter calculates the fluid level in the tank with high accuracy and the result is shown on the display of the electronic board. Further, this information is stored on an SD card and it is transmitted to the server or mobile application through GSM system for further processing.

Description

THE SMART ELECTROMECHANICAL VOLUME AND LEVEL METER FOR FLUIDS USING ENCODER

SENSOR

Currently, for measuring the level of fluids, e.g., water, the following challenges exist:

• Change of hardness of fluid reduces the accuracy of the measuring device • Temperature variation reduces the accuracy of the measuring device • Water vapour over the sensor reduces the accuracy of the measuring device • Covering of minerals on the measuring sensor, e.g., on diaphragm liquid level sensor reduces the accuracy of the measuring device • Chlorine and Lime gas available in tank reduces the accuracy of the measuring device • To the best of our knowledge, there is no fluid level measuring device with automatic calibration • Current measuring devices lack automatic self-diagnostic feature

The existing level meter devices have several drawbacks regarding the accuracy of measuring the fluid level in a tank. This is mainly because they do not use the encoder sensor and use the other types of sensors, e.g., ultrasonic sensor. For instance, the hardness of the fluid and the temperature variation reduce the accuracy of the existing devices. Further, the water vapour and the minerals covering the sensor (e.g., on diaphragm liquid level sensor) reduces the accuracy of the level meter. More importantly, the Chlorine and Lime gases reduce the accuracy of the existing level meters. To resolve the abovementioned drawbacks this invention has been specifically devised to provide an improved electromechanical device with high accuracy and lifetime and reasonable price. This is the first time that an encoder sensor is utilized in a level meter. None of the aforementioned drawbacks listed above affect the encoder sensor accuracy. The proposed level meter is capable of a smart and automatic self-calibration and self-error diagnostics, which results in more accurate measurement of the fluid level compared to the existing level meters. For instance, every time the tank depletes and fills up, level meter is automatically calibrated 6 times. The electromechanical volume and level meter for fluids using encoder sensor consists of four parts: mechanical part, encoder sensor part, control and management part, and smart calibration and error diagnostic part

The mechanical part of this device, which is placed in the tank (containing the fluid), consists of two parts. One part is fixed to the tank wall which is called stand holder of mechanical part and the other part is a ball floating in the fluid which is called main mechanical part. All the parts of the device in the tank are water resistant and stainless. The output of the mechanical part is sent to electrical sensor (encoder). The output of the sensor is transmitted to electronic board. This part performs the required processing and the calculated level (displayed on the electronic board) of the fluid is sent to the server and in turn, server (after sophisticated calculations and analysis) sends this information to cell phones or other client PC.

The stand holder of the device is attached to the wall of tank through two screws. The main mechanical part consists of two frame boxes (attached and fixed to each other), a chain, a chain wheel, a floating ball (attached to holding down weights), a hose, a ring (holding two weights) and two small weights. The chain goes through a chain wheel and the hose and continues down to the bottom of the tank. Then it is passed through a ring connected to holding down weights and passing through the floating ball and fixed to the floating ball. The chain is again connected up to the main mechanical part of the device and forming a complete loop around the chain wheel.

When the tank is filling up with fluid, the chain is going up by the floating part, (the floating part consists of the weight and a floating ball). Note that the floating part is powerful enough to pull the

2018101805 27 Nov 2018 weight up and as a result the chain will be pulled up too. The chain then rotates the chain wheel and passes through the hose and the ring (connected to holding down weights) and goes up and forms a complete loop.

When the level of the fluid in the tank goes down, the weight (attached to the floating ball) and fixed to the chain pulls the chain down, and the chain passes through the ring and hose and rotates the chain wheel in the reverse direction and forms a complete loop.

Therefore, when the level of fluid goes up or down, the floating part goes up or down and because it is attached to the chain, it pulls the chain up or down and rotates the chain wheel clock wise or counter clock wise. This way, the reciprocating motion is converted to rotary motion.

Rotary motion of chain wheel, rotates the shaft of the chain wheel and this shaft is connected to the encoder sensor through a coupling. Hence, the rotary motion of the chain wheel is converted to electronic pulses via encoder sensor and transmitted to the electronic board. This level meter has three sensors: minimum sensor, calibration sensor, and overflow sensor. These aforementioned sensors send their information to electronic board. The electronic board receives this information and use it to identify the encoder error and also identify the breaking down of minimum sensor, calibration and overflow sensor. The electronic board, identify the error in accuracy of the main mechanical part and also identify the mechanical breaking down of the three minimum, calibration and overflow sensors.

The level meter calculates the fluid level in the tank with high accuracy and the result is shown on the display of electronic board. Further, this information is stored on a RAM and is transmitted to the server or mobile application through GSM.

Smart calibration and error identification with minimum calibration and overflow sensors

When the level of the fluid in the tank reaches to the abovementioned sensors their status changes from zero to one and this information is transmitted to the electronic board through a wire.

This part of the device consists of three floating switches. When the level of fluid reaches to these switches their status changes from zero to one and the switch closes. Conversely, when the level of the fluid drops below the switch the status of the switch changes from one to zero and the switch opens. These three switches are designed in a way that the first switch (minimum switch) is installed at the lower part of the device and through a chain (with a specific length) is connected to the second switch which is calibration switch. The calibration switch is also connected to the third switch (overflow switch) through a chain with specific length. From the top of the overflow switch a chain is connected to upper part of the tank.

The three switches have the following functionality:

• Minimum switch failure: if the minimum switch stays open while the calibration switch closes the failure of minimum switch is shown on the display and the failure message is also transmitted to the server.

• Calibration switch failure: if the calibration switch stays open while the overflow switch closes, the failure of calibration switch is shown on the display and the failure message is transmitted to the server.

• Overflow switch failure: if the overflow sensor stays open while the encoder sensor shows a slightly higher level than the registered level of the overflow sensor, the overflow sensor failure is shown on the display and the failure message is also transmitted to the server.

2018101805 27 Nov 2018 • Error of encoder accuracy: When the level of fluid reaches to the calibration sensor level, the calibration sensor closes and its level is compared with the calculated level by encoder. If the difference exceeds the threshold error, inaccuracy message of encoder is sent to the server.

• Encoder sensor error check: In order to measure the accuracy of the device, the fixed difference level between the two calibration and overflow sensors is compared with number of pulses calculated by encoder from calibration sensor activation to overflow sensor activation (encoder is activated when the fluid level reaches to calibration sensor) and the result is sent to the server.

• Overflow: when the level of the fluid reaches to the overflow sensor, its switch closes and the device detects that the tank is full and send the stop message to avoid wasting the fluid.

Electronic Board:

The electronic board receives the information from the sensors and performs the calculations via microcontroller and shows the results on the display. The results are also stored on memory card and are transmitted to the server through GSM or an appropriate mobile application.

Server Program:

The electronic board sends the data to the server via GPRS and SMS. The server then performs the advanced analysis on these data. The server also controls the central management system (mobile application). The main task that the server program performs is as follows:

• All the information related to the all tanks are stored in the server and are displayed via server program. This information include tank name, height and volume of the fluid, environment temperature, overflow information if there is any, calibration information, minimum level of fluid, power supply information (AC power or solar panel), battery charging status, billing information for GSM system, the power of antenna for GSM system, displaying if the tank lead is open or closed, and statistical information of all the parameters,

i.e., height and volume of fluid, temperature, etc.

Note: All of this information can be shared with the other users.

Central Management system:

The central management systems (CMS) is a mobile application, which is usually used by managers and higher authorities, displays all the related data to the tanks. This application operates both online (via GPRS) and offline (via SMS). The main task that the CMS performs is as follows:

• CMS reads all the information related to the all tanks from the server and it displays all these information. This information include tank name, height and volume of the fluid, environment temperature, overflow information (if there is any), calibration information, minimum level of fluid, power supply information (AC power or solar panel), battery charging status, billing information for GSM system, the power of antenna for GSM system, displaying if the tank lead is open or closed, and statistical information of all the parameters,

i.e., height and volume of fluid, temperature, etc.

Note: All of this information can be shared with the other users.

2018101805 27 Nov 2018

Mobile application that configures the electronic board:

When the mobile is connected to electronic board via USB connection, this mobile application displays all the data of the board on the mobile and also configures the electronic board if needed.

This mobile application is capable of programming the electronic board, receiving the stored data on the RAM, and sending the received data to the server.

Illustrations of embodiments of the invention:

Figure 1 shows the chain and the chain wheel of the level meter. As shown in the figure, a shaft passes through the chain wheel. The chain wheel converts the reciprocating movement of the chain to the rotary movement of the shaft. The chain wheel is made up of plastic. The chain is also made up of plastic and its length is twice the height of the tank.

Figure 2 shows the floating part of the level meter. This part of the device consists of two parts: a floating object (made up of Styrofoam) and a holding-down weight connected to the chain and passing through the floating object. The floating part easily keeps the holding-down weight floating in the fluid. When the level of the fluid increases, the floating part pulls the chain up and when the level of the fluid decreases the holding-down weight pulls the floating part down and consequently pulls the chain down.

Figure 3 shows the hose of the level meter. To avoid twisting the chains together, a part of the chain passes through the hose. The hose is made up of plastic and its length is equal to the height of the tank. The chain passes through the hose, which prevents the two parallel parts of the chain from twisting together. Another functionality of the hose is to reducing the friction between the floating object and the chain.

Figure 4 shows the holding-down weight of the level meter. This holding-down weight consists of two parts: a weight and a hook. The chain passes through the hose and then passes through the hook. This part always lies down on the bottom of the tank and hold the chain down to avoid the twisting of the two parallel part of the chains.

Figure 5 shows the chain box of the level meter. This part contains the chain wheel and hold the chain wheel. It also prevent the chain from slipping off. The chain box is made up of plastic.

Figure 6 shows the shaft of level meter. The shaft transfers the mechanical power from the chain wheel to the encoder via coupling. The shaft is made up of Aluminium.

Figure 7 shows the coupling of the level meter. One end of this coupling is connected to the shaft and the other end is connected to the shaft of the encoder. It transfers the mechanical power from the shaft to the encoder and it is made up of plastic. If the current optical encoder is replaced by a magnetic encoder, then a permanent magnet is placed inside the coupling.

Figure 8 shows the encoder of the level meter. Currently, an optical encoder is used in the level meter (as shown in Fig. 8). However, a magnetic encoder could also be used instead of optical encoder. The main functionality of this sensor (encoder sensor) is to converting the rotary motion of its shaft to the electronic pulses. When the chain wheel rotates, it converts the reciprocating movement of the chain to rotary movement, and then the mechanical power (via rotary movement) is transferred to the encoder via coupling. The encoder is then converts the rotary movement to the electronic pulses and sends these pulses to the electronic board to calculate the level of the fluid in the tank. We can use different types of the encoders for this device such as optical and magnetic encoder.

2018101805 27 Nov 2018

Figure 9 (a) shows the magnetic encoder with a permanent magnet. The permanent magnet is used when we use magnetic encoder instead of optical encoder. The permanent magnet is placed on the shaft of the encoder. When the chain wheel rotates, the shaft of the encoder and the permanent magnet rotates on the encoder and the electronic pulse are generated.

Figure 10 shows the inner framework of the level meter. The chain box, shaft, and the rear opening (that plays the role of bush) are installed inside the inner framework. This framework is attached to the ceiling or wall of the tank via two stand holder.

Figure 11 shows the outer framework of the level meter. The inner framework of the level meter is place in the outer framework and riveted to it. Further, the stand holder of the hose is riveted to the front part of the outer framework and the encoders are attached to the rear part of the outer framework.

Figure 12 shows the stand holder of the hose. This stand holder is installed on the front part of the outer framework. It has two holes underneath for incoming and outgoing path of the chain. One of the holes contains the hose (attached to it) all the way to the bottom of the tank.

Figure 13 shows the stand holder of the level meter. The device is mounted to the ceiling or the wall of the tank directly or via Polyvinyl chloride (PVC) plate.

Figure 14 shows the PVC plate of the level meter. This part is made up of plastic which is water resistant. The stand holder of the device is installed on this PVC plate.

Figure 15 shows the rear opening of the inner framework. This part of the device is connected to the inner framework of the device. The shaft passes through rear opening and it also plays the role of bush for the device. It is made up of plastic.

Figure 16 shows the general schematic of the device with different parts.

Figure 17 shows the schematic of the overflow, calibration, and minimum sensors with their connections.

• Overflow Sensor: when the level of the fluid reaches to the overflow sensor, its switch closes and the device detects that the tank is full and send the stop message to avoid wasting the fluid.

• Calibration Sensor: when the level of the fluid reaches to the calibration sensor, its switch closes and the device overwrite the fixed height of calibration sensor on the height of the calibration sensor that is calculated by the encoder. Note that the fixed height of the calibration sensor is initially stored in the EPROM of the device. Further, the height of calibration sensor is always fixed in the tank.

• Minimum Sensor: when the level of the fluid reaches to the minimum sensor, its switch closes and the device send the stop message to the pump that evacuating the fluid from the tank.

Description of Electronic Board of the Level Meter

Figure 18 shows electronic board of the level meter with its different elements. Electronic board consists of the following parts:

1. CPU: This part analyses and processes the information (data). It receives the information (data) from the input and according to the written microcontroller program, it performs the

2018101805 27 Nov 2018 required processing and finally sends the output signal to the appropriate module (i.e., display module, GSM module, relay, RS485 port, etc.)

2. GSM module: This part communicates the information between the electronic board and the server via SMS or GPRS. This communication is bi-directional.

3. GPS module: This part determines the position of the level meter.

4. Hall Effect sensor input: When the Hall Effect sensor senses a magnetic field, it will be activated and then it sends, via this input, the variation of the magnetic field as a voltage to the microcontroller of the CPU.

5. Optical transceiver (IR input/output): It sends and receives the data via infrared signal.

6. Smart power supply: This part charges the battery through AC power or small solar panel. It also controls how much power remained in the battery and stops the charging when the battery is fully charged.

7. Current (4-20 mA) output: This part of the device enables the electronic board to output the height of the fluid (in the tank) as a 4 to 20 mA current, which is readable by the other devices connected to electronic board.

8. Current (4-20 mA) input: the electronic board receives and reads the data of the other devices (connected to it) through this input and performs the processing by its microcontroller.

9. RS485 port: This part of the electronic board allows the establishment of a bi-directional communication between this level meter and the other devices connected to it.

10. Solar panel: When the main AC power is unavailable, this part of the electronic board supplies the power of the board via solar energy.

11. Temperature Sensor: This part of the board senses and reads the temperature of the environment and sends the data to the microcontroller.

12. Micro SD RAM: All of the data collected from the sensors and from the output of the CPU is stored on the Micro SD RAM to be used when required.

13. LCD, Buzzer, and Buttons: The collected data from the sensors are displayed on LCD by microcontroller. The buzzer is used for alarm. The buttons are used for adjusting the internal menu of the device.

14. RTC Block: real-time clock (RTC) keeps track of current time and adjusts the time and date of the device.

15. Voltage (0-5 V) Output: This part of the device enables the electronic board to output the height of the fluid (in the tank) as a 0 to 5 Volt (V) voltage, which is readable by the other devices connected to electronic board.

16. Signal light output: This output port receives the data from microcontroller of CPU and it sends the data to Signal light to control the Signal light, which is used to remotely observe the level of the fluid in the tank.

17. AC output: It receives the external AC power.

18. Encoder connector: This connector connects the encoder sensor to the electronic board for receiving the data.

19. External switch connector: This connector connects the external switches including minimum, calibration and overflow switches to the electronic board for receiving the data.

Claims

The claims defining the invention are as follows:

1. The electromechanical volume and level meter for fluids using encoders consists of four parts: mechanical part, encoder sensor part, control and management part, and smart calibration and error diagnostic part.

2. The level meter as claimed in claim 1 comprising the mechanical part, which converts the reciprocating motion to rotary motion using chain wheel. The reciprocating motion is due to the variation of the fluid level in a tank. The rotary motion is transmitted to the encoder sensor part via coupling.

3. The level meter as claimed in claim 1 comprising an encoder sensor part to measure the volume and the level of the fluid in the tank. As claimed in claim 2, the rotary motion from mechanical part is transmitted to the encoder sensor via coupling. The encoder sensor part then measures the amount of rotations and send the values to the electronic board to measure the level of fluid in the tank. The type of this encoder could be optical or magnetic encoder sensor.

4. The level meter as claimed in claim 1 comprising a control and management part, which includes the electronic board (with microcontroller) and the server and mobile applications. This level meter has three other sensors: minimum sensor, calibration sensor, and overflow sensor. These sensors are used for smart calibration and error diagnostics of the device using microcontroller, and highly accurate measuring of the fluid level. The electronic board receives the data from these sensors and performs the fluid level calculations using its microcontroller. The results are shown on the display of the electronic board. The information of the fluid level is also stored on an SD card which is also sent to server and mobile application via GSM systems.

5. The level meter as claimed in claim 1 comprising a smart (automatic) calibration and error diagnostic part. The zero- and one-pulse signals of minimum, calibration, and overflow sensors are sent to the electronic board for fluid level calculations. These sensors are used to identify the encoder error, checking the accuracy of the encoder calculations and also identifying the failure of minimum, calibration and overflow sensors. If the level meter device becomes out of calibration and its accuracy decreases, when the level of the fluid reaches to each of the abovementioned sensors, it automatically calibrates the device and the fluid level calculations will be performed with high accuracy. That is, every time the tank depletes and fills up, level meter is automatically calibrated 6 times.