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Researchers Submit Patent Application, "MEMS Based Membrane Sensor System and Method of Use", for Approval

July 16, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventors Chatterjee, Aveek (Bangalore, IN); Bhattacharyya, Arjun (Bangalore, IN); Chandrasekaran, Shankar (Chennai, IN), filed on December 21, 2012, was made available online on July 3, 2014.

The patent's assignee is General Electric Company.

News editors obtained the following quote from the background information supplied by the inventors: "The blockage or mechanical failure of a reverse osmosis (RO) or nanofiltration (NF) membrane element can lead to significant downtime of a membrane based water purification plant. There are several offline optical and acoustical devices and methods used to identify a membrane element mechanical failure or the amount of membrane element blockage. However, these devices and methods cannot provide online monitoring and are expensive and time consuming. Accordingly, there is a need for a membrane element mechanical failure and blockage sensor system to identify the presence of a mechanical failure and the presence and amount of blockage in a membrane element. Further, there is a need for a method of using the sensor system to help ensure timely cleaning and/or replacement of the mechanically failed and/or blocked membrane elements."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "In one aspect of the invention, a MEMS sensor system for a membrane based water filtration plant comprises: a remote telemetry unit (RTU), a SCADA, and a plurality of MEMS sensors for measuring pressure, flow rate. and conductivity of a stream; the water filtration plant is comprised of a train comprised of a membrane vessel containing a plurality of membrane elements; the membrane elements receive a feed stream and produce a concentrate stream and a permeate stream; the membrane elements are arranged in series creating interfaces between each membrane element; the MEMS sensors measure the flow rate, pressure, and conductivity of the feed stream, concentrate stream, and permeate stream at the membrane interfaces; the membrane vessel receives a feed stream and produces a permeate stream and a concentrate steam; conventional pressure sensors measure the pressure of the membrane vessel permeate, concentrate, and feed streams; conventional conductivity sensors measure the conductivity of the membrane vessel permeate, concentrate, and feed streams; conventional flow sensors measure the flow rate of the membrane vessel permeate, concentrate, and feed streams; conventional temperature sensor measures the temperature of the membrane vessel feed stream; the RTU communicates with the MEMS sensors and the SCADA to provide the MEMS sensor pressure and conductivity measurements to the SCADA, the RTU communicates wirelessly with the MEMS sensors; the conventional sensors provide measurements directly to the SCADA; wherein the SCADA uses the MEMS sensor and the conventional sensor measurements to identify compromised membrane elements.

"In another aspect of the invention, the system identifies compromised membrane elements by calculating a normalized permeate flow rate, normalized differential pressure, and normalized salt passage for each membrane element using the MEMS sensor and the conventional sensor measurements, and comparing the calculated normalized permeate flow rate, normalized differential pressure, and normalized salt passage for each membrane element to normalized permeate flow rate, normalized differential pressure, and normalized salt passage for each membrane element at reference conditions.

"In another aspect of the invention, the system identifies compromised membrane vessels by calculating a normalized permeate flow rate, normalized differential pressure, and normalized salt passage for the membrane vessel using the conventional sensor measurements, and comparing the calculated normalized permeate flow rate, normalized differential pressure, and normalized salt passage for the membrane vessel to normalized permeate flow rate, normalized differential pressure, and normalized salt passage for the membrane vessel at reference conditions.

"In another aspect of the invention, the membrane element is identified as compromised when the calculated normalized permeate flow of the membrane element is at least about 5% less than the normalized permeate flow of the membrane element at reference conditions; wherein the membrane element is identified as compromised when the calculated normalized differential pressure of the membrane element is at least about 5% greater than the normalized pressure differential of the membrane element at reference conditions; wherein the membrane element is identified as compromised when the calculated normalized salt passage of the membrane element is at least about 5% greater than the normalized salt passage of the membrane element at reference conditions; wherein the membrane vessel is identified as compromised when the calculated normalized permeate flow of the membrane vessel is at least about 5% less than the normalized permeate flow of the membrane vessel at reference conditions; wherein the membrane vessel is identified as compromised when the calculated normalized differential pressure of the membrane vessel is at least about 5% greater than the normalized pressure differential of the membrane vessel at reference conditions; wherein the membrane vessel is identified as compromised when the calculated normalized salt passage of the membrane vessel is at least about 5% greater than the normalized salt passage of the membrane vessel at reference conditions.

"In another aspect of the invention, each of the MEMS sensors is comprised of at least one of a flow sensor, pressure sensor, or a conductivity sensor.

"In another aspect of the invention, each of the MEMS sensors is comprised of a removable smart sensor structure (RSSS) and a control/data transceiver chip (CDTC); the RSSS is comprised of a smart part and at least one of a pressure sensor or a conductivity sensor; wherein the smart part is comprised of a coil, voltage regulator, inductive transceiver, non-volatile memory, microprocessor, and conversion circuitry; wherein the CDTC is comprised of a coil, inductive transceiver, and RF transceiver.

"In another aspect of the invention, each of the MEMS sensor is powered by a battery in the CDTC, or wirelessly by the RTU.

"In another aspect of the invention, each of the MEMS sensors employs one or both of smart power or smart monitoring.

"In another aspect of the invention, each of the MEMS sensors contain housekeeping information.

"In another aspect of the invention, each of the MEMS sensors are mounted to an anti-telescoping device (ATD) of the membrane elements, wherein the MEMS sensors are mounted in a press-fit slot or a fastener slot of the ATD.

"In yet another aspect of the invention, a method of operating a MEMS sensor system for a membrane based water filtration plant comprises: providing a MEMS sensor system and a membrane train, the membrane train is comprised of a membrane vessel containing a plurality of membrane elements, the membrane elements are arranged in series to create membrane interfaces between each membrane element; the MEMS sensor system is comprised of a plurality of MEMS sensors and a SCADA; providing the membrane vessel with a feed stream, wherein the membrane vessel produces a concentrate stream and a permeate stream; the membrane vessel is further comprised of a conventional flow sensor, a conventional pressure sensor and a conventional conductivity sensor in each of the feed stream entering the membrane vessel, and concentrate stream and permeate stream exiting the membrane vessel; wherein the membrane vessel is further comprised of a conventional temperature sensor in the feed stream entering the membrane vessel; providing each of the membrane elements with a feed stream, wherein each of the membrane elements produce a concentrate stream and a permeate stream; the MEMS sensors are placed in the feed stream, concentrate stream, and permeate stream at the membrane interfaces; obtaining normalized permeate flow rate, normalized differential pressure, and normalized salt passage for each of the membrane elements and membrane vessel at reference conditions; prompting the MEMS sensors and the conventional sensors to acquire flow rate, pressure, and conductivity measurements; prompting the conventional temperature sensor to acquire the temperature of the feed stream at time 't'; providing the flow rate, pressure, and conductivity measurements of the feed, permeate, and concentrate streams at the membrane interfaces and the membrane vessel at time 't' to the SCADA; providing the temperature of the feed stream of the membrane vessel at time 't' to the SCADA; calculating the normalized permeate flow rate, normalized differential pressure, and normalized salt passage for each membrane element and membrane vessel at time 't' using the temperature, flow rate, pressure and conductivity measurements obtained at time 't'; and comparing the calculated normalized permeate flow rate, normalized differential pressure, and normalized salt passage of each membrane element and membrane vessel at time 't' and normalized permeate flow rate, normalized differential pressure, and normalized salt passage of each membrane element and membrane vessel at reference conditions to identify compromised membrane elements and membrane vessels.

"In another aspect of the invention, the method further includes retrieving housekeeping information from the MEMS sensors and updating the housekeeping information.

"In another aspect of the invention, the method further includes reporting to a user the normalized permeate flow rate, normalized differential pressure, and normalized salt passage of each membrane element and membrane vessel at time 't', the normalized permeate flow rate, normalized differential pressure, and normalized salt passage of each membrane element and membrane vessel at reference conditions, and the location of the compromised membrane elements and membrane vessels.

"In another aspect of the invention, the membrane element is identified as compromised when the calculated normalized permeate flow of the membrane element is at least about 5% less than the normalized permeate flow of the membrane element at reference conditions; wherein the membrane element is identified as compromised when the calculated normalized differential pressure of the membrane element is at least about 5% greater than the normalized pressure differential of the membrane element at reference conditions; wherein the membrane element is identified as compromised when the calculated normalized salt passage of the membrane element is at least about 5% greater than the normalized salt passage of the membrane element at reference conditions; wherein the membrane vessel is identified as compromised when the calculated normalized permeate flow of the membrane vessel is at least about 5% less than the normalized permeate flow of the membrane vessel at reference conditions; wherein the membrane vessel is identified as compromised when the calculated normalized differential pressure of the membrane vessel is at least about 5% greater than the normalized pressure differential of the membrane vessel at reference conditions; wherein the membrane vessel is identified as compromised when the calculated normalized salt passage of the membrane vessel is at least about 5% greater than the normalized salt passage of the membrane vessel at reference conditions.

"In another aspect of the invention, the conductivity measurements are comprised of measurements of the concentration of individual dissolved analytes of interest and the total concentration of dissolved solids or TDS (total dissolved solids).

"In another aspect of the invention, each of the MEMS sensors is comprised of at least one of a flow sensor, pressure sensor, or a conductivity sensor.

"In another aspect of the invention, the MEMS sensor is comprised of a removable smart sensor structure (RSSS) and a control/data transceiver chip (CDTC); the RSSS is comprised of a smart part and at least one of a pressure sensor or a conductivity sensor; wherein the smart part is comprised of a coil, voltage regulator, inductive transceiver, non-volatile memory, microprocessor, and conversion circuitry; wherein the CDTC is comprised of a coil, inductive transceiver, and RF transceiver.

"In another aspect of the invention, the MEMS sensor is powered by a battery in the CDTC.

"In another aspect of the invention, a remote telemetry unit (RTU) communicates with the MEMS sensors and the SCADA to provide the MEMS sensor pressure and conductivity measurements to the SCADA, wherein the MEMS sensors are powered wirelessly by the RTU.

"In another aspect of the invention, the MEMS sensors employ one or both of smart power or smart monitoring.

"Advantages of the present invention will become more apparent to those skilled in the art from the following description of the embodiments of the invention which have been shown and described by way of illustration. As will be realized, the invention is capable of other and different embodiments, and its details are capable of modification in various respects.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

"These and other features of the present invention, and their advantages, are illustrated specifically in embodiments of the invention now to be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:

"FIGS. 1a-c is a MEMS sensor in accordance with an embodiment of the current invention;

"FIG. 2a is a block diagram of an RSSS in accordance with an embodiment of the current invention;

"FIG. 2b is a block diagram of an RSSS in accordance with an embodiment of the current invention;

"FIG. 2c is a block diagram of an RSSS in accordance with an embodiment of the current invention;

"FIG. 2d is a block diagram of an RSSS in accordance with an embodiment of the current invention;

"FIG. 3 is a pressure sensor in accordance with an embodiment of the current invention;

"FIG. 4 is a conductivity sensor in accordance with an embodiment of the current invention;

"FIG. 5 is a block diagram of a CDTC in accordance with an embodiment of the current invention;

"FIG. 6 is a flowchart depicting the processes taking place within the microprocessor of the MEMS sensor in accordance with an embodiment of the current invention;

"FIG. 7 is a schematic of a MEMS sensor system for a membrane based water filtration plant in accordance with an embodiment of the current invention;

"FIGS. 8a-b is a membrane element in accordance with an embodiment of the current invention;

"FIGS. 9a-c are ATUs of a membrane element in accordance with embodiments of the current invention;

"FIG. 10 is an RTU in accordance with an embodiment of the current invention;

"FIG. 11 is graph showing the measured total conductivity data for a membrane vessel containing a membrane element with an interconnector O-ring failure and the expected total conductivity data for the same membrane vessel containing membrane elements with intact interconnector O-rings; and

"FIGS. 12a-c is a method of operating a MEMS sensor system for a membrane based water filtration plant in accordance with an embodiment of the current invention.

"It should be noted that all the drawings are diagrammatic and not drawn to scale. Relative dimensions and proportions of parts of these figures have been shown exaggerated or reduced in size for the sake of clarity and convenience in the drawings. The same reference numbers are generally used to refer to corresponding or similar features in the different embodiments. Accordingly, the drawing(s) and description are to be regarded as illustrative in nature and not as restrictive."

For additional information on this patent application, see: Chatterjee, Aveek; Bhattacharyya, Arjun; Chandrasekaran, Shankar. MEMS Based Membrane Sensor System and Method of Use. Filed December 21, 2012 and posted July 3, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=1428&p=29&f=G&l=50&d=PG01&S1=20140626.PD.&OS=PD/20140626&RS=PD/20140626

Keywords for this news article include: Electronics, Microprocessors, General Electric Company.

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Source: Electronics Newsweekly


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