Abstract: A gas sampling system is provided having a combustibles detector and an oxygen detector supplied from a common sample line by their own individual aspirators. The aspirators are sized to allow the one aspirator to overpower the second aspirator whenever the common sample inlet is blocked a predetermined amount to thereby cause oxygen rich supply air to flow through the oxygen detector causing the oxygen detector to register an abnormal condition as an indication of blocked sample inlet.

Abstract: A differential thermocouple combustible gas detector is provided by coating one thermocouple junction of a differential thermocouple pair with a catalyst and the other thermocouple junction with a non-catalyst. Heated combustible gases react with the catalyst to liberate heat to the catalyst coated thermocouple junction in proportion to the concentration of combustible gases and proportionally raise the temperature of that junction above the non-catalyst coated junction. The output signal from the differential thermocouple device is thus a signal indicative of the concentration of combustible gases.

Abstract: A fluidic device having a sensing nozzle remotely mounted from an emitter assembly and communicating with it through a connecting tube. An adjustable nozzle assembly, located within the emitter assembly, is movable with respect to an outlet and aligned orifice to provide a zero level output signal from the outlet for various lengths of connecting tube. The nozzle assembly is also adjustable to provide a range independent zero level output signal for different pressure level sensitivities. A test jack communicates with the outlet to monitor the output signal and provide for adjusting the zero level output signal.

Abstract: A fluid sampling system has a series of sample probes having inlets located at different positions across a fluid conveying duct. The outlets of all the sample probes are connected to a valve assembly. Each of the sample probes is made to have substantially the same length and diameter to provide equivalent transport times and volumes to fluids sampled from the various locations. The valve assembly allows selective connection of the sample probes to the fluid analyzer allowing either individual sample probes to be connected to the analyzer to determine local duct conditions or the connection of all the sample probes to the analyzer to determine the average duct condition.

Abstract: A function generator is provided which establishes an output signal according to a functional relationship determined by the preformed contour of an easily precut cam member. The function generator includes a variable gain controller section coupled to a proximity sensing motion balance servomechanism which varies the gain of the controller according to the sensed proximity of the servomechanism to the edge of the cam member without physical contact therewith. The cam member's position is in turn determined by an input signal which may be related to the controller input signals or may be an independent signal from a remote source. The gain and consequently the output of the controller is varied according to the functional relationship determined by the precut contour of the cam member.

Abstract: A pressure sensitive Silicon chip is indirectly bonded to a Stainless Steel housing of an electronic pressure transmitter through an intermediate holder assembly. This indirect bonding prevents thermal cracking of the Silicon chip due to the difference in thermal expansion of the Stainless Steel housing and the Silicon chip. The holder assembly includes a Borosilicate glass tube having the Silicon chip bonded thereto which tube is soldered to a Nickel-Iron alloy holder by a eutectic alloy solder. In assembly, the Nickel-Iron holder is first brazed to the stainless Steel housing at a first temperature greater than the maximum non-destructive temperature of either the chip or the glass tube and the glass tube is then soldered to the Nickel-Iron holder at a lower temperature which will not destroy the chip or the tube holder.

Abstract: A furnace draft control for a fossil fuel fired steam generator wherein the rates of flow of fuel, air and flue gas are adjusted in parallel in accordance with changes in power demand and the forced and induced drafts are adjusted in opposite directions as required to maintain furnace draft at set point.

Abstract: A high stability pneumatic pressure regulator is provided by the use of a movable vane and nozzle assembly to operate a valve plug and thereby change the regulator output pressure. Movement of the vane and nozzle assembly is initiated by an adjustable input member which changes the vane to nozzle spacing and subsequently causes the vane and nozzle assembly to move with the valve plug until the normal vane to nozzle spacing is restored. A feedback of the output pressure is used to balance the adjustable input member.

Abstract: A gas sampling analyzing system is provided whereby flue or process gasses are aspirated from a process duct to an analyzer and are therefrom returned back to the process duct to prevent condensation at the system exhaust. The sampling analyzing system is enclosed in an internally heated manifold to prevent condensation of the sampled gas and insure an accurate analysis by the system. The sampling analyzing system has an analyzer assembly connected in parallel with a drop tube with the combination being connected to a sample probe on one side and to a supply air operated aspirator on the other side. The parallel drop tube allows a high flow rate to be maintained between the sample probe and the aspirator to ensure a faster system response to changes in concentrations of the flue or process gasses.