Abstract: Disclosed is an apparatus for measuring respiratory gas flow, which provides a high accuracy in measurement of the respiratory gas flow and reduces the manufacturing cost of the apparatus, in comparison with the conventional disposable apparatus for measuring respiratory gas. The apparatus includes a measurement module and a respiratory tube assembly. The respiratory tube assembly comprise a cylindrical tube body and a sensing rod inserted through the cylindrical tube body. The sensing rod is shaped like the number “1” and has a plurality of sampling pores and two air passages. Locations of the sampling pores are determined by equal area division method in which a circular section of the cylindrical tube body is divided into a plurality of annuluses with equal areas and the sampling pores are formed at the positions also equally dividing the annuluses to which the sampling pores belong.

Abstract: A high temperature gas flow sensing element module, using Pitot tube technology, for use within a fluid conduit consisting of a housing having an inlet, an outlet, and forming a hollow interior cross-sectional area. Individually, the gas flow sensing element modules fit easily through typical furnace access doors. Thus, in typical furnace retrofit applications, a plurality of equally sized gas flow sensing element modules are arranged adjacent one another in a manner such that the inside dimensions of the entire arrangement coincide with the internal dimensions of the plenum or duct opening into which it is inserted. Pressure averaging piping is used to provide average total and static pressure across the entire gas flow sensing element to differential pressure flow indicators and/or transmitting devices.

Abstract: A method and apparatus are provided for determining an estimate of flow stability, in addition to providing a measurement of flow velocity distribution. To this end, monitoring is provided of the changes over time of flow measurements from a plurality of spaced apart measuring points. An indication of the reliability of the flow velocity distribution measurement is produced based on the estimate of stability.

Abstract: A control valve is located in a variable displacement compressor that is installed in a refrigerant circuit. The control valve operates such that the pressure difference between first and second pressure monitoring points in the refrigerant circuit seeks a predetermined target value. The first pressure monitoring point is located in a discharge chamber of the compressor. The second pressure monitoring point is located in a flow pipe that extends from the discharge chamber. The static pressure of refrigerant in the discharge chamber is introduced into a control valve from the first pressure monitoring point. A pressure that includes the static pressure and the dynamic pressure of refrigerant in the flow pipe is introduced into the control valve from the second pressure monitoring point. As a result, the displacement of the compressor is reliably controlled without being affected by the thermal load of an evaporator.

Abstract: A flow sensor for compressible fluid comprising a central hub having a total pressure chamber and a static pressure chamber disposed therein. A pair of wings extend radially outward from opposing sides of the total pressure chamber. The wings include a plurality of radially spaced holes oriented to generally face an upstream direction and an internal wing passageway connecting the spaced holes to the total pressure chamber. The sensor also includes a static tube having a tube wall extending outward from the static pressure chamber from a first attached end to a second distal closed end. A generally upstream facing hole and a generally downstream facing hole are disposed on opposing sides of the tube wall intermediate the first and second ends to define a fluid flow passage therethrough. An internal tube passageway connects the flow passage to the static pressure chamber.

Abstract: A probe for use in monitoring intake air volume in an air handling system operates in a turbulent stream found at locations near an intake for outside air. The probe has a very large transverse peripheral profile and includes a front face having a very large impact area so as to substantially disturb the turbulent stream and effect a substantial change the direction of flow of the turbulent stream, enabling accurate measurement of differential pressures to determine intake air volume with greater precision.

Abstract: A pump flow test system for accurately measuring the aggregate fluid flow from all pumps of a fire truck. The inventive device includes a reservoir structure for storing a volume of fluid, an intake manifold having a plurality of intake inlets extending into the reservoir structure, an elongate tube extending into the reservoir structure from the intake manifold, a pitot tube positioned within the elongate tube for measuring fluid flow, and a meter attached to the pitot tube for displaying the water flow through the elongate tube. The elongate tube preferably has a cap and a perforated portion for allowing even distribution of the incoming water into the reservoir structure. In use, an intake hose is positioned within the reservoir structure for drawing water into the pumps of the fire truck. A plurality of dispensing hoses are connected to the pump of the fire truck and to the intake inlets of the intake manifold for delivering the water from the pumps of the fire truck to the reservoir structure.

Abstract: Disclosed is a high temperature insertion type flow element and mounting extension assembly for a gas flow measuring device. Designed to overcome the drawbacks associated with compensating for differential thermal expansion between the element and the duct wall, the element consists of an otherwise conventional insertion type flow element, that incorporates the use of a mounting extension assembly and an expansion fitting. The mounting extension positions the element head in an offset manner from the gas duct, placing the element head in a position away from any insulating materials encasing the duct, allowing for convenient access to the instrumentation and cleaning ports. The expansion fitting stabilizes the element tubes within the duct while absorbing any differential thermal expansion.

Abstract: An multi-point, center-averaging airflow sensor comprises a plurality of upstream airflow sensing tubes extending radially from a central hub having a total pressure averaging chamber and a static pressure averaging chamber. The airflow sensing tubes are each provided with at least one total pressure port located inwardly of the outer end of the tubes to minimize error caused by total pressure measurements taken near the inner walls of the conduit in which the sensor is installed. The sensor has static pressure ports located in the side surface of the hub which are shielded from upstream air flow by the tubes and which are preferably at least partially shielded from damper back pressure by notched reinforcing blades provided along the length of the airflow sensing tubes.

Abstract: A method and apparatus for measuring gas flow in a conduit includes the steps of providing a plurality of gas flow measuring devices, positioning the gas flow measuring devices at a plurality of positions in the conduit, and substantially simultaneously measuring the gas flow at each position. A gas flow measuring apparatus includes a plurality of flow-measuring probes, each probe including one or more gas flow measuring devices, a separate pressure transducer connected to each probe, a data logger connected to the transducers, and a computer connected to the data logger.