Abstract: An apparatus and method to monitor parameters outside the wellbore casing of a well includes a Wireless Sensor Unit located outside a section of a non-magnetic casing of the well. The Wireless Sensor Unit includes a sensor device to measure parameters of the surroundings. The apparatus further includes an internal Sensor Energizer Unit inside the wellbore casing used for power and communication with the Wireless Sensor Unit. The Sensor Energizer Unit and the Wireless Sensor Unit are arranged to be at the same elevation, and they communicate data using electromagnetic modulation techniques.

Abstract: An electrical insulator having high mechanical strength is disclosed for use in connection with a force sensor body portion of a weld probe force gage. The force sensing body includes a pair of pockets for receiving a corresponding pair of welding electrodes. The pockets are lined with one or more anodized aluminum alloy inserts. Disposed upon each surface of each insert is a layer of oxide, which acts as an electrical insulator. The inserts are bonded to the receiving pockets so that one layer of oxide is internally disposed between the receiving pocket and the electrode. The force sensor body is fabricated from an aluminum alloy and anodized to form a second oxide layer between the receiving pockets and the inserts. The inserts protect the two oxide layers from external mechanical wear from welding electrodes.

Abstract: This invention relates to a sensor for the direct and continuous measurement of the electrochemical properties of compounds in a high resistivity liquid. The sensor has a housing which includes a porous hydrophilic membrane which may be made of a ceramic, and contains an electrolytic solution. The membrane permits the passage of a portion of the electrolytic solution into the pores thereby facilitating the formation of an interface between the electrolytic solution and the high resistivity liquid and allowing extraction of the compounds in the high resistivity liquid into the electrolytic solution. A porous sensing electrode is positioned directly on the membrane for detecting and measuring the concentration of the compounds extracted from the high resistivity fluid.

Abstract: A sensor for gaseous and vaporous species is disclosed. The sensor comprises an electrically insulated substrate which contains small pores passing completely through it. Electrodes consisting of metallic or semiconductor material are deposited onto the top surface of the substrate. In a first embodiment of the invention, an electrolyte is placed on the top surface of the substrate in such a manner as to create a gas or vapor permeable electrolyte layer on top of the electrodes. In a second embodiment of the invention, the electrolyte is applied to the bottom surface of the substrate and seeps up through the porous holes of the substrate until it makes contact with the electrodes. Both embodiments result in a gas sensor with a response time dependent upon the gas flow rate rather than the time required for the gas to be dissolved in the electrolyte layer and be detected.

Abstract: An optical immunosensing device for detecting the presence of an analyte in a liquid sample is fabricated by coating iron phosphate onto a silicon substrate and then etching the iron phosphate layer to obtain steps of varying thickness. Then, a first mip, capable of immunological reaction with the analyte, is immobilized on the iron phosphate steps. In the preferred embodiment, the first mip is chemically bound to the iron phosphate step surface. The presence of the analyte in the liquid sample is detected by visually observing color changes in the steps after contact of the detection zone with the liquid sample. A change in step color is related to increased thickness which can only result from the binding of the analyte to the first mip immobilized on the iron phosphate step. Aluminum phosphate can also be added to the iron phosphate.

Abstract: An integral interstitial fluid sensor for application to the skin of a person or an animal for the detection of chemical components of tissue fluid is disclosed. The fluid sensor comprises a substrate of a porous material for the passage of the interstitial fluid therethrough. At least two electrodes are provided. One of the electrodes has two sides, with one side mounted on the substrate. The electrode is also of a porous material and permits the passage of the interstitial fluid from one side through to the second side which is generally opposite the one side. A layer of chemical is on the second side. The layer of chemical comprises a chemical for reaction with one component of the fluid, mixed in a mediating agent. The electrodes generate an electrical signal upon the detection of the reaction of the one component of the fluid with the chemical. The electrical signal is received by a detector and a display is generated, indicating the amount of the one component detected.

Abstract: A zero tracking circuit (32) monitors the output of an electronic scale employing a dual slope integrating type analog-to-digital converter (20) to detect low magnitude output signal levels characteristic of drift and other low level noise. The converter (20) samples the magnitude of an input analog signal proportional to applied weight and in response controls a count accumulated in a resettable up/down counter (36). The counter (36) is manually reset to provide tare, that is, to provide a zero reading with an applied weight. The output of the counter (36) is supplied to a digital display (40a-40d) that displays changes in applied weight. The zero tracking circuit (32) includes a decoder (56) that monitors the output of the counter (36) and in response to low magnitude counts characteristic of drift, e.g., one count on each side of zero, resets the counter (36) to eliminate the drift.

Abstract: A low profile scale utilizes four strain gage-based sensing beams which are isolated from mechanically or thermally-induced distortions on the weighing platform by means of interposed elastic elements. The platform is capable of moving upwardly relative to the sensing elements without transmitting any load thereto. The platform cooperates with a floating lower enclosure system to essentially seal the mechanism so that it is splash proof and washable as required for use in the food industry. Adjustable overload stops channel excess forces around the sensing beams to protect them from damage.

Abstract: A scale for precise weighing measurements utilizing a strain gauge load cell includes a weighing platform which is cantilevered to one side of the load cell in order to permit a high profile load cell to be used while retaining a low platform height. An overload protection system causes the platform to bottom out against a fixed supporting base when a predetermined load is exceeded.