Abstract: Disclosed are various embodiments related to a corrosion detection device for detecting corrosive environments. A corrosion detection device comprises a magnetic sensor and at least one magnetic nanowire disposed on the magnetic sensor. The magnetic sensor is configured to detect corrosion of the one or more magnetic nanowires based at least in part on a magnetic field of the one or more magnetic nanowires.

Abstract: The present invention relates to a marine structure comprising an external surface (50), a load (2, 20, 21, 22, 25) comprising a light source, said load having a first load terminal (2a) and a second load terminal (2b) adapted to be powered by an AC power source (1), said AC power source (1) having a first AC terminal (1a) electrically connectable to the surface (50) and a second AC terminal (1b), a first electrode (3) electrically connected to the first load terminal (2a), and a dielectric layer (4). The first electrode (3) and the dielectric layer (4) are arranged to form, in combination with the surface (50), a capacitor (6) for capacitive transmission of electrical power between the first electrode (3) and the surface (50). The second AC terminal (1b) and the second load terminal (2b) are arranged to be electrically connected to an external electrically conductive element (10, 11) insulated from the surface (50). The first load terminal (2a) is electrically insulated from the second load terminal (2b).

Abstract: A plasma-assisted synthetic jet device, an aircraft including a plasma-assisted synthetic jet device, and a method of improving aerodynamic properties are disclosed for providing air flow control at an aerodynamic structure by ionizing one or more gases exiting through an aperture of the synthetic jet device disposed in the aerodynamic structure.

Abstract: A device comprising an electrically conductive surface portion is provided for immersion in an electrically conductive liquid such as water. At least one load electrode is provided for supplying an electric load current into the electrically conductive liquid. Further, an electrode, e.g., one or more of the at least one load electrode acts as protection electrode. A protection current source, e.g., a resistor, is electrically coupled to the conductive surface portion and to the protection electrode for providing a protection current flowing between the electrically conductive surface portion and the electrode. Further, the protection current source is adapted for changing the protection current in response to a change in the load current.

Abstract: Methods, systems, and apparatuses for measuring an electric potential in the earth, which includes a first sensor are disclosed. The first sensor includes a sensing plate for placement in an environment in close proximity to the earth. The sensing plate has an operative capacitive coupling with the earth and measures the earth's electric potential. The sensor also includes a barrier providing electrochemical segregation between the sensing plate and the earth and an amplifier having at least one stage for receiving and amplifying a first signal carrying the potential measured by the sensing plate. The sensor also includes a first connection carrying the first signal from the sensing plate to the amplifier; and a reference voltage for application to the first stage of the amplifier, the reference voltage providing a reference against which the potential measured by the sensing plate is compared. Other embodiments are described and claimed.

Abstract: An impressed current cathodic protection system for a target structure susceptible to corrosion (such as of steel or cast iron) which comprises an inert mixed metal oxide anode surrounded by a tightly packed conductive zone connected to a power supply source and having an input/output regulator to control the flow of current to the target structure. The present invention relates to device and method to provide personal and/or medical details of one or more individuals in the event of an emergency.

Abstract: A method for conducting a peel test of a polymer coated metallic sample includes making a peel test specimen having a polymer joined to a substrate. A free portion of the polymer is left unattached to the substrate. The peel test specimen is positioned in an environment for testing in such a manner that the polymer is allowed to peel downward from the substrate. A weight is joined to the free portion of the polymer and a start time is recorded. The attached portion of the polymer is periodically measured and the elapsed time is recorded. A peel rate is calculated from the measurement and time.

Abstract: A method and device for facilitating maintenance of an anode of a marine engine cooling system, the device including an anode for use with an anode plug such as, for example, an anode plug that has a detachable component with a threaded end for mounting to a threaded bore of a cooling system structure, and a connector that holds the anode, the anode having an indicator for indicating a condition of the anode which is indicative of a need to replace the anode The method permits changing the anode by removing and/or reinstalling an anode while preventing or minimizing water from exiting the cooling system of the marine engine.

Abstract: An impressed current cathodic protection arrangement includes an elongate metallic structure to be protected and cathodic protection apparatus which comprises a DC power supply and an anode. One terminal of the power supply is connected to the structure at a connection point and another terminal of the power supply is connected to the anode. The arrangement includes monitoring apparatus for monitoring effectiveness of cathodic protection provided by the cathodic protection apparatus by determining the electrical potential of the structure relative to surroundings at at least one location which is spaced from the connection point.

Abstract: A marine drive cathodic protection control circuit and method controls ohmic current from a power source to an anode according to electrical reference potential sensed by a reference electrode. The ohmic current is interrupted for an interruption interval, and reference potential is sensed during the interruption interval. The ohmic current is controlled according to reference potential sensed during the interruption interval.

Abstract: According to various embodiments, a system includes a gasifier that includes a shell made of a first material exposed to a gasification region inside the gasifier and a patterned anode layer coupled to the shell inside the gasifier. The patterned anode layer is made of a second material, and the patterned anode layer is configured to protect the shell from corrosion by condensing hot gas in the gasification region.

Abstract: A system for detecting and preventing galvanic corrosion of an anodic metal includes a potential detector configured to monitor an electrical potential within the electrolyte solution, a signal amplifier coupled with the potential detector, and a current delivery circuit coupled with the signal amplifier. The signal amplifier is configured to provide an output proportional to the monitored electrical potential, and the current delivery circuit is configured to provide a current to a cathodic metal that is proportional to the output of the signal amplifier.

Abstract: A method is provided for corrosion protection in a marine construction, such as a marine surface vessel or a marine structure, the marine construction including at least one metal element and a sacrificial anode adapted to be at least partly immerged in an electrolyte in the form of water, in which the marine construction is at least partly immerged, the at least one metal element including a metal part, the sacrificial anode being provided for corrosion protection of the metal part. The method includes connecting at least one of the at least one metal element and the sacrificial anode to a DC electrical power outlet so as to allow an electric de-passivation current through an electrical circuit including the sacrificial anode, the metal element and the electrolyte.

Abstract: A method for corrosion protection in a marine construction including a plurality of metal elements and at least one reference electrode at least partly immerged in water, the metal elements including an anode and a metal part, the anode being provided for corrosion protection of the metal part includes measuring an electric potential of the metal part with the reference electrode as a ground reference. At least one of the metal elements and at least one of the at least one reference electrode are connected to a DC electrical power outlet so as to allow an electrical regeneration current through an electrical circuit including the at least one of the metal elements, the at least one of the at least one reference electrode and the electrolyte so that the reference electrode is anodized.

Abstract: According to various embodiments, a system includes a turbine engine component that includes a first material having a surface exposed to a fluid flow path and a sacrificial anode layer disposed on the surface. The sacrificial anode layer includes a second material that is electrochemically more active than the first material and the second material is configured to preferentially corrode to protect the first material from corrosion.

Abstract: An apparatus and method for monitoring cathodic protection of a protected object that includes a probe with five segments in series. The cathodic protection is provided by a system with a power supply that impresses current onto the protected object. An anode is included with the system that is also connected to the power supply. The third and fifth segments are in electrical communication through a frangible connection; that over time galvanically corrodes to electrically isolate the third and fifth segments. The second segment, which is a permanent isolator, is set between the first and third segments. The third segment is selectively connected with the protected object. When the third segment is selectively disconnected from the protected object, measuring the potential difference between the third segment and the first segment yields a value for object polarization that is void of IR error.

Abstract: A method in a corrosion protection system for protecting a first and a second metal part of a marine construction is provided. The method includes controlling electrical currents through electrical circuits, including respective anodes, the respective metal parts and an electrolyte, at least partly based on measured electrical potentials of the respective metal parts with an reference electrode as a ground reference. The method further includes repetitively performing the steps of controlling the electrical currents so as to be reduced or eliminated, measuring the electrical potentials while the electrical currents are maintained reduced or eliminated, and, after measuring the first and second electrical potentials, controlling the electrical currents so as to be increased or reestablished.

Abstract: Apparatus for connection to a metallic structure, the apparatus comprises a transformer rectifier unit operable to output a DC current for cathodic protection of a metallic structure, and a modulator unit connected to receive a DC output from the transformer rectifier unit. The modulator unit is arranged for connection to a metallic structure, and is operable to produce a modulated current which is applied to such a metallic structure when the apparatus is in use, such that the metallic structure is detectable by a wireless locating device. The modulator unit is operable to be controlled remotely.

Abstract: A corrosion inhibiting system is provided with the ability to allow both primary and secondary portions of the circuit to be used in the alternative without having the primary and secondary systems interfere with each other by operating at the same time. By incorporating a continuity controller, such as a switch or a diode to selectively disconnect the sacrificial anode from the circuit, the primary and secondary systems can both be provided on a marine vessel, but used independently from each other. In that way, the primary and secondary corrosion inhibiting systems are prevented from interfering with each other during normal operation.

Abstract: A method and system for protecting underground gas carrier pipes housed within an outer casing pipe in which a gas carrier pipe section disposed within an outer casing pipe section and having opposed ends is electrically isolated from a remaining gas carrier pipe section proximate each of the ends. An annular space between the gas carrier pipe section and the outer casing pipe section is filled with an electrolyte. At least one anode electrode is inserted into the annular space distal from each of the gas carrier pipe section and the outer casing pipe section and connected with a positive voltage lead of a cathodic protection rectifier. A negative voltage lead of the cathodic protection rectifier is connected to the gas carrier pipe section.

Abstract: A method is disclosed for using an impressed current cathodic protection (ICCP) system that supplies an electrical current such that a metallic structure (10) has a negative voltage of between 0.5 and 1.5 Volt relative to earth to power one or more electrical appliances (5), the method comprising: —providing one or more electrical appliances (5) which each have a pair of electrical contacts (1,2); —connecting one electrical contact (1) of each electrical appliance to the structure; and —connecting the other electrical contact (2) of each electrical appliance to earth, thereby providing electrical power to each of the electrical appliances. It is preferred that the electrical appliances (5) are equipped with one or more DC-DC power converters (6) which are configured to enhance an electrical input voltage of between 0.5 and 1.5 Volt to an electrical output voltage of between 3 and 5 Volt.

Abstract: A single anode system used in multiple electrochemical treatments to control steel corrosion in concrete comprises a sacrificial metal that is capable of supporting high impressed anode current densities with an impressed current anode connection detail and a porous embedding material containing an electrolyte. Initially current is driven from the sacrificial metal [1] to the steel [10] using a power source [5] converting oxygen and water [14] into hydroxyl ions [15] on the steel and drawing chloride ions [16] into the porous material [2] around the anode such that corroding sites are moved from the steel to the anode restoring steel passivity and activating the anode. Cathodic prevention is then applied. This is preferably sacrificial cathodic prevention that is applied by disconnecting the power source and connecting the activated sacrificial anode directly to the steel.

Abstract: The present invention includes systems, methods and apparatus for continuously, independently and in some cases remotely monitoring the operation of a current interrupter used to test a cathodic protection system, or the cathodic protection system itself, for verification of proper operation. Embodiments of the invention include electronic devices that may be temporarily attached to a current interrupter that is being used to test a cathodic protection system, or directly to the cathodic protection system itself. Embodiments of the invention monitor the activity of an interrupter by sampling the output (voltage and time) to identify the cycle(s) of the interrupter. The invention provides truly independent verification since it does not need to know in advance the sequence or cycle times of the current interrupter being monitored. The information obtained by the invention is output so that it may be provided to a user, displayed, downloaded or stored for future reference.

Abstract: An apparatus, system, method and computer program product directed to controlling corrosion, particularly space weather induced corrosion, of a conductive structure in contact with a corrosive environment and coated with a semiconductive coating, where the corrosion is controlled by a controllable filter and a corresponding electronic control unit configured to process and adjust the controllable filter in response to at least one measured parameter associated with space weather effects on the conductive structure.

Abstract: The invention consists of a bunker to visually hide and structurally protect a cathodic protection rectifier located in an open field or urban areas where there is high incidence of vandalism. The bunker consists of a mobile element which contains a rectifier and an underground cavity structure. Besides hiding and protecting the rectifier from vandalism, the only part of this apparatus that is normally visible is a circular plaque at ground level, with a waterproof seal. Occasionally the rectifier is removed for maintenance and diagnostic purposes. In order to extract the mobile element it is necessary, but not enough, to have a magnetic or electromagnetic anchor with a great load capacity. The mobile element may only be extracted when the bolt lock located at the base of the cylinder is wirelessly activated. The cavity structure has radial plates calculated to dissipate the heat produced through the operation of the rectifier. All electric connections are hidden and embedded in concrete.

Abstract: A cathodic protection device having a sacrificial anode that is intended to wear out due to corrosion and that is electrically connected to a structure to be protected against corrosion. The cathodic protection device of the present invention further includes an indication device configured to detect and indicate the wear of the sacrificial anode wirelessly, without the use of cables.

Abstract: The present invention includes systems, methods and apparatus for continuously, independently and in some cases remotely monitoring the operation of a current interrupter used to test a cathodic protection system, or the cathodic protection system itself, for verification of proper operation. Embodiments of the invention include electronic devices that may be temporarily attached to a current interrupter that is being used to test a cathodic protection system, or directly to the cathodic protection system itself. Embodiments of the invention monitor the activity of an interrupter by sampling the output (voltage and time) to identify the cycle(s) of the interrupter. The invention provides truly independent verification since it does not need to know in advance the sequence or cycle times of the current interrupter being monitored. The information obtained by the invention is output so that it may be provided to a user, displayed, downloaded or stored for future reference.

Abstract: A novel cathodic protection system is provided that automatically controls and adjusts the voltage potential between an anode and a structure to protect the structure from corrosion. The cathodic protection system is self-powered, requiring no external power source or batteries. A cathodic protection circuit is configured to provide a cathodic protection current from the anode to the structure through an electrolyte. A power generation circuit is configured to generate power from a galvanic cell formed from the anode and an isolated electrode when cathodic protection is interrupted. A voltage potential control circuit is powered by the power generation circuit and is configured to (a) determine a structure-to-electrolyte reference voltage for the electrolyte and structure, and (b) adjust the cathodic protection current from the anode to the structure to maintain the reference voltage substantially the same as a set voltage.

Abstract: Apparatus 10 discloses a subsea monitoring station using solar cells to energize at least one electronic circuit incorporating at least one node having a determinable circuit value or other parameter test station providing a full time voltage readout, powered by the lights 16 on an ROV/AUV 14 or diver's lamp. An additional element of the apparatus is a subsea cathodic protection test station 18 incorporating a plurality of banks of solar cells 28 powering DC voltage test circuits having some form of parameter display, such as voltmeter readout 30, deriving voltage from ambient light 16 provided by outside sources, such as an ROV 14 or diver's lamp. The apparatus's cathodic protection test system includes four integral voltmeters 30 of which are powered with independent solar panels 28. The solar panels 28 are powered by artificial light 16 delivered by diver or submersible vehicle 14.

Abstract: A method for preventing corrosion of a contact, includes comparing a potential of a signal line connected to the contact with a predetermined potential corresponding to the corrosion of the contact; flowing a corrosion-prevention current into the contact when a result of the comparing shows that the contact is corroded; inputting into the signal line a signal used for judging a logical value of a connection state of the contact; and in the magnitude relation, setting the predetermined potential on another side of a threshold level used in the judging of the logical value of the connection state of the contact.

Abstract: A water heater having a powered electrode and a method of controlling the water heater. The water heater includes a tank to hold water, a heating element, an electrode, and a control circuit. The control circuit includes a variable voltage supply, a voltage sensor, and a current sensor. The control circuit is configured to controllably apply a voltage to the electrode, determine the potential of the electrode relative to the tank with the voltage sensor when the voltage does not power the electrode, determine a current applied to the tank after the voltage powers the electrode, determine a conductivity state of the water in the tank based on the electrode potential and the current, and define the voltage applied to the powered electrode based on the conductivity state. The control circuit of the water heater can also determine whether the water heater is in a dry-fire state.

Abstract: An apparatus, system, method and computer program product directed to controlling corrosion of a conductive structure in contact with a corrosive environment and electrically connected to one or more anodes, wherein the anodes are less noble than the conductive structure, where the corrosion is controlled by a controllable filter and a corresponding electronic control unit configured to process at least one stored or measured parameter, and wherein the apparatus, system and method serve to prolong the lifetime of the one or more anodes by reducing, minimizing or substantially eliminating their sacrificial character.

Abstract: A sacrificial marine anode with a water proof encased current tester to alert an operator of proper connectivity, current status of the cathodic protection system for an associated marine structure, and status of current tester power supply is disclosed.

Abstract: A portable, handheld, automatic protection level interpreting cathodic protection meter for testing the level of protection being afforded to metallic structures protected by either sacrificial anode or impressed current cathodic protection systems, or both. The meter is suitable over a variety of environments including salt water, freshwater, and soil. The operator can select both the type of metal to be tested as well as the type of reference electrode that is being used. The meter automatically calibrates data interpretation of the level of protection based on the operator's selections and eliminates any voltage drop error existing between a reference electrode and the structure being protected.

Abstract: The present invention generally provides a method for prevention of corrosion in a metal object by inducing a surface current over the entire surface of the metal object. The surface current can be induced by direct or indirect application of electrical waveforms having AC components generated from a circuit. The metal body and the negative terminal of a source of DC voltage (battery) are grounded. The positive terminal of the source of DC voltage is connected to the electronic circuit that imparts electrical waveforms of low voltage DC to the conductive terminal connected to the metal body. Alternate methods of inducing surface currents include direct capacitor discharge through the metal body, or movement of an electromagnetic field over the metal body, or by generating an RF signal attached to a transmitting antenna such that the transmitted signal is received by the metal body.

Abstract: The invention is a redox control and monitoring platform that is to be used in conduction with another detection scheme. The platform includes a portion of an electrochemical control. The electrochemical control can be operated to control and measure the redox environment of a sample. The electrochemical control can be provided in a multiplicity of test regions to allow high throughput analysis of a multiplicity of samples. The present method and system allows the determination of the effect of the change in redox environment on the binding or other activity of the species in the sample that is directly affected by the redox environment.

Abstract: A method and test apparatus for carrying out testing on a variety of samples of polymer bonded to metal wherein the samples are subjected to an accelerated cathodic reaction causing cathodic delamination of the samples. In particular, the method and test apparatus include a closed vessel that is partially filled with synthetic ocean water. An impressed current system is employed to protect the metal component of the samples. The synthetic ocean water is heated with an external band heater raising the temperature of the synthetic ocean water to thermal levels exceeding normal ocean temperatures in order to accelerate the reaction. Pure oxygen is then introduced into the closed vessel at a desired pressure to dissolve the oxygen into the synthetic ocean water to further simulate natural ocean conditions.

Abstract: An apparatus, system, method and computer program product directed to controlling corrosion of a conductive structure in contact with a corrosive environment and coated with a semiconductive coating, where the corrosion is controlled by a controllable filter and a corresponding electronic control unit configured to process at least one stored or measured parameter.

Abstract: An apparatus for indicating when a predetermined portion of a sacrificial anode has been corroded comprises a detector embedded within the interior of the sacrificial anode initially at a predetermined distance from an exposed exterior surface of the sacrificial anode. The detector detects the absence of sacrificial anode material when the predetermined portion has corroded and generates a detection signal. A monitoring system communicates with the detector for receiving detection signals and generates an indicator signal when a detection signal is received. An indicator in communication with the monitoring system receives indicator signals and generates an alarm when an indicator signal is received.

Abstract: A system using tank corrosion sensors to provide for an overall assessment and monitoring of the electro-chemical corrosion and coatings condition in ships' tanks, and particularly in ships' seawater or compensated fuel tanks. The system includes reference half-cells mounted along a suspended cable and one instrumented sacrificial anode at the end of the cable to provide optimal sensing capability within a tank structure. The reference half-cells and the sacrificial anode measure a potential and current output, respectively. Together the measurements provide objective information that can be used to predict corrosion damage and coating deterioration occurring throughout the structure of the tank. The system may be used for an overall assessment and monitoring of the electrochemical corrosion and coatings condition. In a preferred embodiment, the measurements are stored in a datalogger that is optimally contained within an associated instrument housing.

Abstract: A system using tank corrosion sensors to provide for an overall assessment and monitoring of the electro-chemical corrosion and coatings condition in ships' tanks, and particularly in ships' seawater or compensated fuel tanks. The system includes reference half-cells mounted along a suspended cable and one instrumented sacrificial anode at the end of the cable to provide optimal sensing capability within a tank structure. The reference half-cells and the sacrificial anode measure a potential and current output, respectively. Together the measurements provide objective information that can be used to predict corrosion damage and coating deterioration occurring throughout the structure of the tank. The system may be used for an overall assessment and monitoring of the electro-chemical corrosion and coatings condition. In a preferred embodiment, the measurements are stored in a datalogger that is optimally contained within an associated instrument housing.

Abstract: Re-usable, energy-efficient apparatus for the restoration of corrosion-damaged reinforced concrete and a method for controlling the same. The apparatus includes a combination electrode device in a sandwich construction that includes a dimensionally stable electrode, a reusable electrolyte reservoir, an ion exchanger element, a reference electrode, a power-switching device for anodic regulation, and a measuring system for determining the capacity of the ion exchanger element to take up ions. Use of this combination electrode device prevents the formation of active chlorine during extraction of chlorine from reinforced concrete.

Abstract: A monitor for use in conjunction with a galvanic protection system for a marine vessel provides automatic and continuous monitoring of a voltage at a reference electrode of the galvanic protection system and displays the results continuously by energizing one or more of a plurality of annunciators, such as light emitting diodes. The light emitting diodes are energized in groups of one or two in order to double the effective resolution of a group of ten annunciators. The selected annunciators are energized intermittently in order to conserve electrical power while continuously and automatically running. The frequency of activation of the selected annunciators is changed whenever the voltage potential being monitored falls within a minimum range or a maximum range in order to alert the operator of a potentially catastrophe result. A lower frequency is used when the monitor voltage is not within these minimum and maximum ranges.

Abstract: An apparatus for indicating when a predetermined portion of a sacrificial anode has been corroded comprises a detector embedded within the interior of the sacrificial anode initially at a predetermined distance from an exposed exterior surface of the sacrificial anode. The detector detects the absence of sacrificial anode material when the predetermined portion has corroded and generates a detection signal. A monitoring system communicates with the detector for receiving detection signals and generates an indicator signal when a detection signal is received. An indicator in communication with the monitoring system receives indicator signals and generates an alarm when an indicator signal is received.

Abstract: An apparatus, system, method and computer program product directed to controlling corrosion of a conductive structure in contact with a corrosive environment and coated with a semiconductive coating, where the corrosion is controlled by a controllable filter and a corresponding electronic control unit configured to process at least one stored or measured parameter.

Abstract: An automated, remote control/monitoring system for a cathodic protection system for a buried metallic object based on monitoring multiple coupon test stations, buried next to the metal object, by a central processor, which can individually control multiple cathodic protection rectifiers. Preferably, the reference for potential measurements is a buried coupon having a metallurgy substantially the same as the metallurgy of the buried object.

Abstract: An apparatus, system, method and computer program product directed to controlling corrosion of a conductive structure in contact with a corrosive environment and coated with a semiconductive coating, where the corrosion is controlled by a controllable filter and a corresponding electronic control unit configured to process at least one stored or measured parameter.

Abstract: Numerical techniques such as the finite element method (FEM) are used to model the current and voltage distribution in concrete structures such as bridges. The geometric arrangement of groundbeds and the ideal locations for the electrical contacts vis-a-vis the geometry of the bridge and the rebars can thereby be predicted and a cathodic protection (CP) system for the bridge designed. A magnetic sensor is used to sense the magnetic field generated by the CP current, and a voltmeter or an oscilloscope to measure the output of the magnetic sensor. A current interrupter is also used to interrupt the CP current at the source. The current is mapped by placing the magnetic sensor on or above the concrete surface. By moving the sensor from one location to another, the current is mapped over the entire structure. To achieve uniform distribution over the entire structure, an “expert” CP system controlled by a variety of current and environmental sensors and a dedicated microprocessor is described.

Abstract: A cathodic protection system for corrosion protection of metallic structures in contact with aqueous solutions such as salt water and calcium chloride brine. The system employs anode chambers containing hydroxide anolytes segregated from the electrolyte containing chloride by an ion-exchange membrane. The anode and the structures to be protected are coupled to voltage and current sources impressing current at the immersed surfaces of metallic structures to maintain these surfaces close to an equipotential and covered with a bound layer of polarized hydroxide. The preferred embodiment is used in connection with stainless steel holding tanks and associated equipment used to circulate calcium chloride brine to freeze whole muscle turkeys. When the brine and the anolyte contact the membrane, a bi-ionic potential forms across the membrane that drives the counter-directed transport of ions through the membrane, thereby preventing the anodic production of Cl2.

Abstract: Disclosed is a method for fabricating biosensors, using hydrophilic polyurethane. Bio-active reagents, including enzymes, antibodies, antigens, cells and receptors, are mixed with hydrophilic polyurethane and the mixture is directly coated over a signal transducer to form a sensing film which serves as a signal detector. The method using hydrophilic polyurethane allows the simplification of the fabrication of biosensors without conducting complicated chemical reactions and washing steps, such as crosslinking. The bio-active reagent entrapped within the hydrophilic polyurethane film can retains its high activity for an extended period of time and the intrinsic potentiometric response of the underlying ion-selective polymeric membrane is not affected by the bio-active reagent immobilized polyurethane film coated on its sensing surface. Therefore, the biosensors are superior in specificity, selectivity, and stability.