FIELD OF THE INVENTION
The present invention relates generally to a system for transmitting load cell signals from the load cell which senses the weight of accumulated ash in hoppers or any other load sensitive equipment to remote locations, and relates more particularly to utilization of radio frequency (RF) transmission technique for transmitting the load cell signals along with monitoring, storing and analyzing the transmitted load cell signals to give appropriate control commands for controlling efficient functioning of the overall system which may be Electrostatic Precipitators (ESPs).
BACKGROUND OF THE INVENTION
In coal fired thermal power plants, Flue gas that is generated as a result of combustion is passed through super heaters, reheaters, economizers, air preheaters, Electro static precipitators (ESPs) before finally reaching chimney for getting exhausted to the outside. Flue gas carries particulate matter such as, for example, ash particles, unburnt particles along with it which makes flue gas more polluted. The fly ash carried with flue gas gets removed before reaching the chimney while it is passed through the ESP. Fly ash, which is removed by the ESP gets collected in a number of hoppers below the ESPs, overfilling of which may cause malfunctioning of the overall system.
ESP hoppers are continuously filled with hot fly ash. Along with the effects of humidity and high temperature, fly ash tends to stick to the sides of the hopper which can cause material build-ups and clogging of the hopper which can damage the ESP plates. End-users need to continuously monitor the volume of fly ash and its actual distribution inside the hopper so that they can be emptied on time, maintained and cleaned when necessary. This is essential in order to prevent clogging-up and risks of damage to the ESP plates. Additionally, damaged plates can create environmental and health concerns as well.
Conventionally, to prevent over-filling of collected Fly-ash from these hoppers, emptying process is performed with an Automatic Level Detection System or load cell mechanism. In Automatic Level Detection System, the High and Low Level of Fly-ash in

the ESP Hoppers are monitored to start the emptying process only when the pre-set maximum Level is reached. A load cell mechanism which monitors the weight of the ash and generate alarm when the weight reaches a pre-set maximum level to start the emptying process only when the pre-set maximum Level is reached to prevent over-filling and subsequent catastrophic, if ignored. A load cell usually consists of four strain gauges (Full Bridge) in a Wheatstone bridge configuration. When the load is applied to the body of a resistive load cell, it creates strain at those locations due to the stress applied. As a result, two of the strain gauges are in compression, whereas the other two are in tension. The resistance of four strain gauges changes because of this compression and expansion. This change in resistance leads to a change in output voltage which is being measured as output voltage across two terminals of Wheatstone bridge. The measured output voltage will be given to load monitoring system through cables. In power plant, this cable routing through various zones to remote location induces the noise into the signal and leads to faults in the cables which interrupts operations. However, drawback of said cabling systems lies in its limitation to monitor load only from shorter distances.
Further, in US6,275,682B1 is disclosed a radio frequency (RF) signal transmitting device adapted to transmit signals between a computer and a plurality of Wireless peripheral equipment. The RF signal transmitting device includes a plurality of RF signal transmitters and an RF signal receiver. The RF signal transmitters are electrically connected to the plurality of Wireless peripheral equipment, respectively, and each is provided for modulating an output signal there from into an RF signal with a specific carrier frequency and transmitting the RF signal. The RF signal receiver is electrically connected to the computer for synchronously receiving the RF signals from the RF signal transmitters and converting each of the RF signals to an operating signal to operate the computer.
Furthermore, US6,864,779B2 discusses a method for transmitting data from a remote location for evaluation by an expert. A remote appliance couples a data collection device with a communications device to transmit collected data and serve as a virtual

remote presence server where the remote appliance is adapted to transmit collected
data. The remote appliance transmits the data in accordance with subscriber
information stored in a centralized device. The data can be processed or evaluated in
any manner.
Further, US7,309,989B2 discloses a system for wirelessly supplying electrical power to an RF coil and an analog-to-digital converter (ADC) for an MRI system. The system supplies power to at least operate the RF coil and ADC without the use of a battery and without use of a wired connection external to the bore of the magnet.
Additionally, the teaching disclosed in US8,823,423B2 is on apparatus for a wireless tachometer receiver. The wireless tachometer receiver includes a receiver and a signal conditioner that drives a conventional tachometer. Conventional tachometers require an input consisting of pulses at the operating voltage of the vehicle, which is typically 12 Vdc. Conventional receivers have an alternating current output that is substantially less than the operating voltage of the vehicle, which is insufficient to trigger the tachometer reliably. The signal conditioner converts the receiver output to a signal that allows for reliable operation of the conventional tachometer.
Further, discussed in US2005/0180523A1 is a method of wirelessly transmitting digital signal includes the steps of (a) dividing a digital signal into a primary signal band and a secondary signal band; (b) phase-shifting the secondary signal to form a reverse signal with respect to the primary signal band in such a manner that the reverse signal is one hundred and eighty degrees out of phase with the primary signal band; (c) encoding the primary signal band and the reverse signal; (d) wirelessly transmitting the primary signal band and the reverse signal; (e) decoding the encoded primary signal band and the encoded reverse signal; and (f) combining the primary signal band and the reverse signal to re-form the digital signal.
Furthermore, US2013/0147427A1 discusses a wireless electric field power transmission system and method wherein the wireless electric field power transmission system

comprises: a transmitter comprising a transmitter antenna, the transmitter antenna comprising at least two conductors defining a volume there between; and at least one receiver, wherein the transmitter antenna transfers power wirelessly via electric field coupling when at least one receiver is within the volume.
In another conventional technique generally related to transmitting RF signal to a receiver US2014/0369444A1 discloses a method of wireless communication provided between the transmitter and the receiver, in which the transmitter transmits to the receiver the RF signal where carrier phase of the RF signal is randomly converted and the receiver detects an envelope of the RF signal, and extracts data from the RF signal.
Those knowledgeable in the art would agree that all the above conventional techniques are related generally to techniques for RF transmission and are not suited to accurately transmit the electrical signals that are generated due to payload weight on the load cell to Load monitoring system stationed at a remote location.
There exist conventional techniques for utilizing RF techniques for load measurement, detection and transmission such as, for example US7157919B1 to Walton discloses a system and method for detecting soot and or ash loading within a filter is provided. Said method comprises the steps of transmitting a source RF signal through a filter, measuring a reflected RF signal, measuring a transmitted RF signal, calculating reflected power by comparing the source RF signal with the reflected RF signal, calculating attenuated power by comparing the source RF signal with the transmitted RF signal, and determining soot loading based on reflected power and transmitted power. The proposed system may also be configured to determine ash loading. Further, US7260930B2 to DeCou discloses a radio frequency-based particulate loading monitoring system, said particulate loading monitoring system includes frequency transmitting probe configured to transmit radio frequency signals of predetermined magnitude and predetermined frequency toward the filter medium and at least one radio frequency receiving probe configured to receive and measure the magnitude of received radio frequency signals that pass through the filter medium. Further, the system

includes a temperature sensing device configured to take a temperature measurement indicative of a temperature of the particulate trap at the time the radio signals are received by the receiving probe and a controller, which may be configured to determine, based on the measured magnitude of received radio frequency signals, a particulate loading value indicative of the amount of particulate matter trapped in the filter medium. Furthermore, US9400297B2 to Bromberg for determining loading of a filter having a first dielectric constant with a material having a different dielectric constant is disclosed. The filter is contained within a metallic container forming a microwave cavity, and microwave or RF energy is created within the cavity and changes in the cavity microwave response are monitored where the changes in cavity microwave response are related to filter loading. Further, US 8942887B2 to snopko teaches an exhaust particulate filter system where the control system for the exhaust particulate filter includes a sensing mechanism such as an RF soot sensor and a data processor coupled with the sensing mechanism and configured to output a moisture compensation signal responsive to a pattern of inputs from the sensing mechanism indicative of moisture within the exhaust particulate filter, for controlling regeneration thereof.
The shortcomings associated with the conventional techniques calls for the development of load monitoring system through intelligent utilization of RF transmission techniques by setting up an arrangement equipped to accurately transmit, monitor and analyze the accumulated load in the hoppers as well timely issuance of alerts in case the analysis shows signs of malfunctioning which are of utmost importance to keep the overall system up and running.
OBJECTS OF THE INVENTION
An object of the invention is to overcome the aforementioned and other drawbacks existing in prior art systems and methods.
Another object of the invention is develop a system and method for transmitting signals from the load cell indicative of payload weight at a field to remote location by using RF transmission.

Still another object of the invention is to monitor and analyze the transmitted RF signal at a remote location for accurate determination of the of the payload weight.
Yet another object of the invention is to issue alerts/warnings to the users located at a remote location in the event of the measured payload weight reaching alarming levels.
SUMMARY OF THE INVENTION:
The present application discloses a Radio-Frequency based system for transmitting load cell signal to a remote location and monitoring thereof as described in Figures 1 to 4. In one aspect, the system includes the load cell (2) configured to convert the payload weight received from a load sensitive equipment into an electric voltage signal representing load cell output voltage. The system further includes a transmitting section (4) configured to process the electric voltage signal before transmitting the processed electrical voltage signal toward a remotely located RF receiver (16) contained in an receiving section (6) wirelessly via an RF transmitter (15) contained in the Transmitting section (4). Further, the system includes an RF receiver (16) contained in the receiving section (6) configured to demodulate the processed electrical voltage signal received via an RF transmitter (15) wirelessly. In an aspect, the demodulated processed electrical voltage signal is represented in form of serial data. Furthermore, the receiving section (6) configured to further process the demodulated processed electrical voltage signal. Further, the system includes a load monitoring section (7) configured to monitor the payload weight by converting the numeric value of analog signal into a payload weight value representing the payload weight sensed by the load cell (2). Further, the load monitoring section (7) is configured to store the payload weight value into a database server (9) via at least one of wired and wireless networks, thereby facilitating the users to access the payload weight value and generate alert to users in event of the payload weight value reaching a pre-set maximum level defined for the payload weight.
In another aspect, the present application disclosing a Radio-Frequency based method for transmitting load cell signal to a remote location and monitoring thereof includes processing the electric voltage signal by an transmitting section (4) before transmitting

the processed electrical voltage signal toward a remotely located RF receiver (16) contained in a receiving section (6) wirelessly via an RF transmitter (15) contained in the transmitting section (4). The method further includes demodulating the processed electrical voltage signal received via an RF transmitter (15) wirelessly by an RF receiver (16) contained in the RF receiving section. In one aspect, the demodulated processed electrical voltage signal is represented in the form of serial data. Furthermore, the method includes further processing of the demodulated processed electrical voltage signal. Further the method includes monitoring the payload weight by converting the numeric value of analog signal into a payload weight value representing the payload weight sensed by the load cell (2) by the load monitoring section (7). Furthermore, the method includes storing the payload weight value into database server via at least one of wired and wireless networks, thereby facilitating the users (10) to access the payload weight value by the load monitoring section (7) and generating alert to users in event of the payload weight value reaching a pre-set maximum level defined for the payload weight by the load monitoring section (7).
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The drawings refer to embodiments of the invention in which:
Fig. 1 illustrates an RF based prior art system for transmission of load cell electrical
voltage signal.
Fig. 2 illustrates a block diagram of an embodiment of the system used for RF based transmission of load cell electrical signal.
Fig. 3 illustrates a block diagram of an embodiment of the system showing the components of the Transmitting section (4) which includes Amplifier (11), ADC (12), Encoder (13) and RF Transmitter (14).
Fig. 4 illustrates a block diagram of an embodiment of the system showing the components of the Receiving section (5) which includes RF Receiver (15), Decoder (16) and Digital to Analog Converter (17).

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.
It will be apparent, however, to one of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well known components or methods have not been described in detail but rather in a block diagram in order to avoid unnecessarily obscuring the present invention. Further specific numeric references should not be interpreted as a literal sequential order. Thus, the specific details set forth are merely exemplary. The specific details may be varied from and still be contemplated to be within the spirit and scope of the present invention. The features discussed in an embodiment may be implemented in another embodiment. The term coupled is defined as meaning connected either directly to the component or indirectly to the component through another component.
Turning now to the drawings, and referring first to FIG. 1, an RF based prior art system for transmission of load cell electrical voltage signal is illustrated. The reference to the conventional system is made in order to better distinguish the present inventive disclosure discussed later in greater detail. The details of the conventional process for transmitting the load signal to the remote location are well-known in the art, and therefore, are described herein only in the detail required to fully disclose the present invention. In certain embodiments, the present invention builds upon the disclosures of US6,275,682B1, US6,864,779B2,US7,309,989B2,US8,823,423B2,US2005/0180523A1, US2013/0147427A1,US2014/0369444A1,US7157919B1,US7260930B2,US8942887B2, CA1322222C which are all hereby incorporated by reference in their entirety.
The components of the conventional system as shown in FIG.1 can be seen to include a load sensitive equipment which is discussed herein primarily as being an Electro static

precipitator (ESP) Ash Hopper (1), a load cell (2), and cables which may be of the type including but not limited to copper long distance cables, coaxial cables, fiber optical cables, optical hybrid cables and signaling cables for transmitting the signals generated at the load cell to the users located at remote location (3). In one embodiment, the ESP ash hopper (1) may be more than one depending on the demand of the plant layout and the quantity of fly ash generated. For the purposes of explanation, throughout the description, fly ash will be discussed as being payload weight.
The system as shown in Fig.1 measures the amount of payload based on the principle of change in the strain in the Wheatstone bridge due to load applied. The change in the strain manifests in the form of voltage signals across the terminals and transmitting the said signals through means of cables or wirelessly or antennae in other aspects to a remote location where the payload is determined by further manipulation of the transmitted signal.
Improving upon the conventional techniques discussed at length above, in the present disclosure the load cell output voltage corresponding to the load accumulated in ESP ash hoppers (1) is fed to the transmitting section (4) for transmitting the signals to a remote location via a receiving section (5). The receiving section (5) reconstructs the received signal into original signal transmitted from load cell. The reconstructed signal will be given to load monitoring section (7), where load will be monitored and stored in a database (8) coupled with a database server (9) via internet or LAN (7) or via any other wired or wireless modes. Once the data is available over the internet or LAN (7), users 1-N (10) can access data from anywhere in the world through well known techniques. Further, the stored data may be analyzed and based on said analysis issue appropriate control commands for controlling efficient functioning of overall system which in the preferred embodiment is an ESP located at a field/plant. The control commands mentioned aforesaid in one aspect are in the form of warning/alarm/trip annunciation when the load reaches a pre-set maximum levels. The intelligent arrangement of the components as shown in Fig. 2-4 clearly makes the system as disclosed in the present application advantageous over the existing arts as would also become clearer to the

knowledgeable in the art with the particulars of the aforesaid techniques being described below in greater detail.
Fig. 2 shows a block diagram of an embodiment of the system used for RF based transmission of load cell electrical signal from field/plant or locations where ESP ash hoppers are stationed to a remote location (3). Fig. 2 can be seen to include in a preferred form ESP ash hopper (1), load cell (2), transmitting antennae (5) where RF antennae comprises RF transmitter antenna and RF receiver antenna, Receiving section (6), load monitoring system (7), database (8) coupled with the database (DB) server, users 1-N (10) located at a remote location and internet or LAN (11) for allowing the users 1-N (10) to access the payload weight data accumulated at the bottom of the ESP ash hopper. In one aspect the load cell is configured to convert the payload weight received from load sensitive equipment into an electric voltage signal representing load cell output voltage. Further, in one embodiment an transmitting section (4) is configured to process the electric voltage signal before transmitting the processed electrical voltage signal toward a remotely located RF Receiver (16) contained in a RF receiving section (6) wirelessly via a RF Transmitter (16) contained in the transmitting section (4).
In one aspect, the Transmitting section (4) processes the electric voltage signal before transmitting said signal to the remotely located RF Receiver (15). The processing of the electric voltage signal performed by the intelligently arranged components contained in the transmitting section (4) which will be discussed in greater detail in Fig. 3. The processing of the electric voltage signal involves firstly, amplifying the electric voltage signal by an amplifier (12) and then followed by the steps of converting an analog electric voltage signal into a set of digital signals by an ADC (13), converting the set of digital signals into serial data by an encoder (14), transmitting the encoded serial data to the RF Transmitter (15) and lastly modulating the encoded serial data by the RF Transmitter (15).
Further, in one aspect, the RF Receiver (15) contained in the RF receiving section demodulates the processed electrical voltage signal received via RF transmitter

wirelessly, wherein the demodulated processed electrical voltage signal is represented in form of serial data. Furthermore, in one form, the receiving section further processes the demodulated processed electrical voltage signal. Further, in another aspect, the receiving section (16) the components of which is disclosed in greater detail in Fig.4 further processes the demodulated processed electrical voltage signal by decoding the serial data into the set of digital signals by a decoder (17) and converting the serial data into numeric value of analog signal representative of the electric voltage signal generated at the load cell by an DAC (18).
Further, the output of the receiving section (6) numeric value of analog signal representative of the electric voltage signal and which is further indicative of the payload weight value of the accumulated load at the bottom of the ESP ash hopper (1) is fed to the load monitoring section (7) which in one aspect is adapted to store monitor the payload weight by converting the numeric value of analog signal into a payload weight value representing the payload weight sensed by the load cell, store the payload weight value into a database server via at least one of wired and wireless networks, thereby facilitating the users to access the payload weight value and generate alert to users in event of the payload weight value reaching a pre-set maximum level defined for the payload weight. In one aspect, the users 1-N (10) located remotely can access the payload weight data via wired or wireless communication.
Shown further in Fig. 3 is a block diagram of an embodiment of the system illustrating the components of the RF signal Transmitting section (4) which includes Amplifier (12), ADC (13), Encoder (14) and RF Transmitter (15).
In one embodiment, the load cell (2) output voltage corresponding to the accumulated load in ash hopper (1) will be in millivolts (mV) which cannot be transmitted effectively. Hence, the load cell output is connected to amplifier (12) which amplifies the load cell output voltage from mV to Volts (V). The amplified voltage is given to the ADC (13) to convert the analog voltage into a set of digital signals i.e., in terms of data bits without which data cannot be transmitted wirelessly. The principal objective of an ADC (13) is to determine the output signal word corresponding to an analog signal. In one embodiment

the ADC 13 being used may be an 8-bit ADC. Additionally, the ADC 13 may be an 8-bit converter with 5V as input power supply. The digital output varies from 0 to 255. Further, ADC needs a clock to operate. It is worth noting that the time taken to convert the analog to digital value depends on the clock source. In another embodiment, an external clock may be given to ADC through implementation of resistors and capacitors. The converted digital signals is given to encoder (14), which is configured to convert a set of signals into a code i.e., converts the set of digital signals into serial data. The above generated encoded serial data is given to RF transmitter (15), which modulates the encoded signal and transmits the modulated encoded signal to the remote location by means of RF transmission.
Figure 4 illustrates a block diagram of an embodiment of the system showing the components of the RF signal receiving section (5) which includes an RF Receiver (16), a Decoder (17) and a Digital to Analog Converter (DAC) (18). The RF receiver (16), which receives the transmitted signal from RF transmitter (15), demodulates the received signal. The demodulated received signal is represented in the form of serial data which is then fed to Decoder to decode the code into set of digital signals i.e., conversion of serial data into parallel data at receiving section. The converted parallel data/set of digital signals is given to DAC (18), which converts the parallel digital data bits into numeric value of analog signal, which is the voltage output measured by the load cell as shown in Figure 2. The numeric value of the analog signal is indicative of the payload weight value accumulated at the bottom of the ESP ash hoppers.
The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.

WE CLAIM
1. A system for transmitting load cell signals indicative of payload weight in a load cell (2), wherein the load cell (2) is located at a remote location (3) from users (10), and wherein the load cell (2) is configured to convert the payload weight received from a load sensitive equipment into an electric voltage signal representing load cell output voltage, the system further comprising:
a transmitting section (4) configured to process the electric voltage signal before transmitting the processed electrical voltage signal toward a remotely located RF receiver (16) contained in an receiving section (6) wirelessly via an RF transmitter (15) contained in the Transmitting section (4);
an RF receiver (16) contained in the receiving section (6) configured to
demodulate the processed electrical voltage signal received via an RF
transmitter (15) wirelessly, wherein the demodulated processed electrical voltage signal is represented in form of serial data;
the receiving section (6) configured to further process the demodulated processed electrical voltage signal;
a load monitoring section (7) configured to:
monitor the payload weight by converting the numeric value of analog signal into a payload weight value representing the payload weight sensed by the load cell (2);
store the payload weight value into a database server (9) via at least one of wired and wireless networks, thereby facilitating the users to access the payload weight value; and
generate alert to users in event of the payload weight value reaching a pre-set maximum level defined for the payload weight.

2. The system as claimed in claim 1, wherein the transmitting section (4) configured
to process the electrical voltage signal comprises:
amplifying the electric voltage signal by an amplifier (12);
converting an analog electric voltage signal into a set of digital signals by an
ADC (13);
converting the set of digital signals into serial data by an encoder (14); and
transmitting the encoded serial data to the RF transmitter (15) and modulating
the encoded serial data by the RF transmitter (15).
3. The system as claimed in claim 1, wherein the receiving section (6) configured to
further process the electrical voltage signal comprises:
decoding the serial data into the set of digital signals by a decoder (17); and converting the serial data into numeric value of analog signal representative of the electric voltage signal generated at the load cell by an DAC (18).
4. The system as claimed in claim 1, wherein the monitoring comprises monitoring by one or more users located at the remote location (3).
5. The system as claimed in claim 1, wherein the load sensitive equipment comprises ESP ash hopper (1).
6. A method for transmitting load cell signals indicative of payload weight in a load cell (2), wherein the load cell is located at a remote location (3) from users (10), and wherein converting the payload weight received from a load sensitive equipment into an electric voltage signal representing load cell output voltage by the load cell (2) the method comprising:
processing the electric voltage signal by an transmitting section (4) before transmitting the processed electrical voltage signal toward a remotely located RF receiver (16) contained in a receiving section (6) wirelessly via an RF transmitter (15) contained in the transmitting section (4);

demodulating the processed electrical voltage signal received via an RF transmitter (15) wirelessly by an RF receiver (16) contained in the RF receiving section, wherein the demodulated processed electrical voltage signal is represented in form of serial data;
further processing the demodulated processed electrical voltage signal by the receiving section (6);
monitoring the payload weight by converting the numeric value of analog signal into a payload weight value representing the payload weight sensed by the load cell (2) by the load monitoring section (7);
storing the payload weight value into database server via at least one of wired and wireless networks, thereby facilitating the users (10) to access the payload weight value by the load monitoring section (7); and
generating alert to users in event of the payload weight value reaching a pre-set maximum level defined for the payload weight by the load monitoring section (7).
7. The method as claimed in claim 1, wherein the processing the electrical voltage signal comprises:
amplifying the electric voltage signal by an amplifier (12);
converting an analog electric voltage signal into a set of digital signals by an
ADC (13);
converting the set of digital signals into serial data by an encoder (14); and
transmitting the encoded serial data to the RF transmitter (15) and modulating
the encoded serial data by the RF transmitter (15).

8. The method as claimed in claim 1, wherein the further processing the electrical
voltage signal comprises:
decoding the serial data into the set of digital signals by a decoder (17); and converting the serial data into numeric value of analog signal representative of the electric voltage signal generated at the load cell (2) by a DAC (18).
9. The method as claimed in claim 1, wherein the monitoring comprises monitoring
by one or more users located at the remote location (3).