Abstract: A gas sensor (22) for detecting the presence of a selected component in a gas (41) includes a substrate (28) exhibiting a low thermal resistance. A heater element (34) is disposed substantially over a surface area of a first surface (30) of the substrate (28). Sensor and reference elements (36, 38), formed from a single metal trace (54), are disposed on a second surface (32) of the substrate (28). The electrical resistivity of the sensor element (36) changes as the sensor element (36) adsorbs molecules of the selected component. During a regeneration process, the heater element (34) is activated to provide substantially even heating over the surface area of the first surface (30). Heat from the heater element (34) conducts through the substrate (28) to heat the sensor element (36) and the reference element (38) to a regeneration temperature sufficient to cause the adsorbed molecules of the selected component to be liberated.

Abstract: A gas sensor (22) for detecting the presence of a selected component in a gas (41) includes a substrate (28) exhibiting a low thermal resistance. A heater element (34) is disposed substantially over a surface area of a first surface (30) of the substrate (28). Sensor and reference elements (34, 36), formed from a single metal trace (54), are disposed on a second surface of the substrate. The electrical resistivity of the sensor element (34) changes as the sensor element (34) adsorbs molecules of the selected component. During a regeneration process, the heater element (34) is activated to provide substantially even heating over the surface area of the first surface (30). Heat from heater element (34) conducts through the substrate (28) to heat the sensor element (34) and the reference element (36) to a regeneration temperature sufficient to cause the adsorbed molecules of the selected component to be liberated.

Abstract: A hydrocarbon detector (20) includes a gas stream delivery element (26) configured to discharge a carrier gas (70) onto a surface (24). The carrier gas (70) serves to volatilize a hydrocarbon presence (22) from the surface (24). A gas stream recovery element (28) is configured to aspirate a sample gas (78) formed from the carrier gas (70) combined with the hydrocarbon presence (22) volatilized from the surface (24). A hydrocarbon sensor (58) detects the hydrocarbon presence (22) in the sample gas (78) and generates an output signal indicative of the hydrocarbon presence (22). An indicator (80) receives the output signal and indicates the hydrocarbon presence (22) in the sample gas (78). A heat source (72) coupled to the gas stream delivery element (26) heats the carrier gas (70) to further aid in the volatilization of the hydrocarbon presence (22).

Abstract: A hydrocarbon detector (20) includes a gas stream delivery element (26) configured to discharge a carrier gas (70) onto a surface (24). The carrier gas (70) serves to volatilize a hydrocarbon presence (22) from the surface (24). A gas stream recovery element (28) is configured to aspirate a sample gas (78) formed from the carrier gas (70) combined with the hydrocarbon presence (22) volatilized from the surface (24). A hydrocarbon sensor (58) detects the hydrocarbon presence (22) in the sample gas (78) and generates an output signal indicative of the hydrocarbon presence (22). An indicator (80) receives the output signal and indicates the hydrocarbon presence (22) in the sample gas (78). A heat source (72) coupled to the gas stream delivery element (26) heats the carrier gas (70) to further aid in the volatilization of the hydrocarbon presence (22).

Abstract: A temperature controlled gravimetric moisture analyzer (20) is used to control the temperature of a sample material (24) while determining moisture content of the sample material (24). The moisture analyzer (20) includes a thermally conductive sample holder (22) having an emissive surface (44). A high precision force balance (30) is coupled to the sample holder (22) for weighing the sample material (24). A heater (26) encloses the sample material. An air temperature sensor (38) is configured to produce an air temperature signal (54). An infrared temperature sensor is configured to detect infrared emissions from the emissive surface (44) to produce a sample temperature signal (60) representative of the temperature of the sample material (24). A controller receives the air and sample temperature signals (54, 60) and controls the heater (26) in response to the signals.

Abstract: A gas sensor for detecting the presence of a specified gas within a mixture includes a silicon substrate, a silicon nitride membrane supported by the substrate, a thin gold sensor trace deposited on the membrane, and a thin gold reference trace deposited on the membrane. A molybdenum adhesion layer is employed between the membrane and the gold traces. The electrical resistance of the sensor trace changes when the sensor trace adsorbs molecules of the gas. Solid state construction facilitates quick and efficient regeneration of the sensing capability of the gas sensor. The silicon nitride membrane and the molybdenum adhesion layer do not adversely affect the resistivity of the gold traces. An alternate gas sensor embodiment includes an integrally formed heater element.

Abstract: Apparatus for determining the actual and proportional amounts of a volatile fluid in a test staple is described. The test staple is stored in a sealed container after being collected and kept in the sealed container through testing. The volatile fluid of interest is evolved from the test sample and a carrier gas transports the volatile fluid past a sensor. The sensor determined the relative amount of the volatile fluid of interest in the carrier gas. The flow rate of the carrier gas is precisely known and is predetermined. A microcomputer is utilized to predict with great accuracy the actual and proportional amount of the volatile fluid in the test sample.

Abstract: A system for measuring moisture content in a porous material uses a microprocessor. The sample of material is placed on a load cell which provides an output to an analog-to-digital converter. The analog-to-digital converter provides a digital input for the microprocessor. The microprocessor is capable of providing an output indicative of the moisture content as a wet basis or a dry basis output. The system provides a highly accurate measurement of the moisture content while minimizing operator errors.