Abstract: An apparatus for filter backwashing includes a vessel containing a bed of filter media. Laterals with nozzles are disposed below the filter media to convey backwashing air and water into the filter bed. Below the laterals are located a manifold and a distribution plenum to carry air into the laterals. The manifold and the distribution plenum are separated by a common wall having a plurality of ports to provide communication therebetween. Communication between the distribution plenum and the laterals is provided by a plurality of conduits, one conduit extending into each lateral from the distribution plenum.

Abstract: In a gas chromatography system of the type including an oven for the GC column, and an electric heater for controllably heating the oven; an improved system is disclosed for controllably opening and closing the oven door to enable a fully controlled heat leak, thereby to stabilize the oven temperature at a desired set point. A signal indicative by first or second conditions of an oven temperature above or below the set point is generated. A heater power control responds to one of the signal conditions by effecting heating of the oven. Bi-directional door motor and actuator means are provided for opening and closing the oven door over a prescribed operating range, and these means are enabled to operate for a predetermined period upon the signal in its first or second condition departing from preset threshold values for a predetermined period whereby closing or opening of the oven door is effected in incremental steps.

Abstract: An object surrounded by media of differing acoustical impedances (e.g., an anatomical organ surrounded by other kinds of tissue within the human body) is acoustically imaged by an array of ultrasonic transducers affixed to the outer surface of an ultrasonic lens. In a preferred embodiment, the lens is homocentric, with the common center of curvature of the inner and outer surfaces of the lens being located at a relatively small acoustic aperture in the body so that object points distributed over a relatively large solid angle from the aperture can be imaged with minimum lens aberations. Where the object to be imaged is a human heart, the acoustic aperture is most conveniently located at an intercostal space between adjacent ribs.

Abstract: Dimensionally optimized flame ionization detector for use in chromatography in which positive ions are caused to be collected by applying positive potential to flame tip. It has been discovered that there exists optimum dimensions of the collector electrode and the spacing between collector electrode and flame tip to resist glassing and corrosion without diminishing other operating parameters. The collector electrode inside diameter is in the range of 0.114 inch to 0.3 inch and the flame tip to collector electrode is in range from 1 mm to 3 mm.

Abstract: In a liquid chromatography system, the effluent from the chromatographic column is passed through a detector flow cell, which is packed with a stationary phase that is adsorptive of the sample species to be detected. Detection of the sample species adsorbed at the stationary phase is effected by measuring fluorescence emitted from such species in response to electromagnetic radiation incident thereon at the flow cell. The fluorescing species, which are in equilibrium between the stationary phase and the mobile phase in the flow cell when fluorescence is being measured, can be detected at lower concentration thresholds than when the fluorescing species are in equilibrium only with the mobile phase.

Abstract: This thermostatable flow cell for fluorescence measurements enables rapid thermal equilibration and precise temperature control. For a flow cell volume of less than 20 microliters, a selected temperature in the range up to 20.degree. C. above ambient can be attained within five seconds, and this selected temperature can be maintained stable within 0.1.degree. C. The cell comprises a cylindrical cavity whose walls include a metallic portion for heat conduction and a transparent window portion for light acceptance and fluorescence observation. The metallic portion of the cell is formed from a cell block to which a temperature sensing means is affixed. The window portion is affixed to the cell block by an inert bonding material. A thermoelectric device responsive to the temperature sensing means causing heating or cooling of the cell block as necessary to provide thermal equilibration at the selected temperature.

Abstract: A duct system for distributing humidified air from a humidifier has a duct and an eliminator sheet assembly mounted at an outlet of the duct. The eliminator sheet assembly includes eliminator sheets movably mounted in the outlet of the duct, and means for securing the eliminator sheets in a plurality of positions so that the direction of air discharged from the outlet can be changed. A structural member for mounting the eliminator sheet assembly at the duct includes a track defined by sidewalls, one of which sidewalls extends upward of the other to capture droplets emitted from the eliminator sheet assembly, and a drain plate assembly for catching condensation falling from the duct. The drain plate assembly includes an elongated trough for attachment to the duct, the trough having two sidewalls and a flexible partition. The partition has an inverted V-shaped cross section and divides the trough into two compartments extending side-by-side.

Abstract: Process and apparatus for micro-coulometric determination of sulfur in hydrocarbon samples in which interference of chlorine and oxides of nitrogen is minimized. The process comprises the steps of oxidizing the sample, scrubbing the oxidized sample with a tin-containing agent and coulometrically titrating the sample thereafter.

Abstract: An assembly for restraining emitting electrodes (14) in an electrostatic precipitator of the type having collecting electrodes (12, 13) arranged in rows spaced at equal distances in parallel planes and spaced-apart emitting electrodes (14) hung in rows centrally between adjacent collecting electrodes (12, 13), such assembly including a rigid electrically-conductive grid (16) suspended from and maintaining the mutual spacing of the emitting electrodes (14), non-conductive rods (34) attached to and extending out from the grid (16) toward the walls (10) of the precipitator, and non-conductive plates (38) attached to the walls (10) interposed between the ends of the respective rods (34) and the walls (10).

Abstract: Chemical analysis apparatus such as a spectrophotometer including an atomizer for receiving a sample to be analyzed and being heated by resistance heating. Control means being provided to vary the voltage across the atomizer, and consequently its temperature, and a feedback circuit is connected between the atomizer and the control means and includes components which are operable to generate an electrical analogue which at least approximates the heating response characteristics of the atomizer. The feedback circuit functions as a negative feedback loop so as to modify the power input to the atomizer by application of the aforementioned electrical analogue, and in that way substantially compensates for the heating response characteristics of the atomizer such that the temperature time profile of the atomizer follows a predictable path.

Abstract: A sector assembly for disc filters including an improved sector body, an improved bell member and two sector rods which extend along respective radial sides of the sector body and of the bell member to secure the sector body to the bell member. Each radial side of the sector body being formed to define a concave channel and formed to define within the channel a concave slot. Each radial side of the bell member being formed to define a concave channel and formed to define a passage inward of the channel. The slots and passages being dimensioned to allow the respective sector rod to extend therein.

Abstract: Chemical analysis apparatus such as a spectrophotometer, having a carbon rod or other non-flame atomizer which is adapted to be heated by electrical resistance heating. The atomizer is included in a heater circuit, and a particular relationship exists between the electrical resistance of the atomizer and the electrical resistance of the remainder of that circuit. That relationship is such that variations in the atomizer resistance as may occur over a period of use, do not substantially affect power dissipation in the atomizer during heating. Ideally, the two resistance values are equal, but variations from the ideal are satisfactory in practice. A feed-back circuit is arranged to maintain a substantially constant voltage across the heater circuit, and that is achieved by comparing the applied voltage with a reference voltage and modifying the applied voltage as necessary to maintain a predetermined relationship between the two.

Abstract: A damper for use with a high pressure pumping system, such as a liquid chromatography system, which incorporates a reciprocating pump. The device is a generally enclosed canister including an internally formed flow volume. Inlet and outlet passages through the canister communicate with the flow volume, the inlet passage being connectable to receive the high pressure flow. A compressible body, e.g. of Teflon is positioned in the flow volume. The dimensions of the body are slightly smaller than those of the surrounding volume, whereby the high pressure flow passing between the inlet and outlet flows through the space between the body and the internal canister walls. The compression and decompression of the body in response to the pulsations in the flow dissipate the energy carried by the pulses, thereby damping same.

Abstract: A circuit improvement is disclosed for use in an electron capture detector of the type including an electron capture cell, means for applying polarization pulses to the cell to derive a cell current, means for varying the pulse rate to maintain the cell current constant, and means for converting the pulse frequency to an analog signal indicative of the concentration of an electron-capturing component.

Abstract: An ionization detector, such as an electron capture detector for use in pesticide residue analysis, utilizes a scandium tritide beta particle source. The scandium tritide forms a surface portion of a metallic foil. If the foil initially exhibits an unacceptably high tritium emanation rate at desired high operating temperatures, e.g., at temperatures above 250.degree. C, the foil can be treated so as to exhibit an acceptable tritium emanation rate at such temperatures. The treatment comprises heating the foil at a predetermined treatment temperature, e.g., at a selected temperature in the 300.degree. to 400.degree. C range, until the tritium emanation rate for the foil at the selected treatment temperature reaches a value which correlates with an acceptable tritium emanation rate for the foil at a particular desired operating temperature.

Abstract: A two-flame burner is used in a flame photometric detector for analyzing a sample material. The sample material is introduced via a first conduit structure into a hydrogen-rich first flame, and the combustion products and excess hydrogen from the first flame are passed via a second conduit structure into an oxygen-containing environment. A second flame is maintained at the exit end of the second conduit structure. The first and second conduit structures are composed of material that does not contribute to the coloration of the second flame during operation of the detector. Particular constituents of the sample material are detected by observing the presence of colors in the second flame indicative of the constituents. For example, the presence of sulfur is indicated by a blue coloration, and the presence of phosphorus is indicated by a green coloration.

Abstract: The pressure range, pumping speed and through-put of a high-vacuum pump can be significantly improved, particularly with respect to the pumping of hydrogen, by making pump components that are exposed to the vacuum from an alloy that is metallurgically stabilized to maintain a body-centered cubic crystal lattice structure throughout the range of temperatures usually experienced by the pump. In a sputter-ion pump, the cathode especially should be made from an alloy stabilized in the body-centered cubic crystal lattice form. A suitable alloy, which is so stabilized in the body-centered cubic crystal lattice form, has a major constituent comprising one or more elements selected from Group IV B of the conventional long form of the Periodic Chart of the Elements, and a minor constituent comprising one or more elements selected from Groups III B, V B, VI B and VII B of the Chart, with the minor constituent constituting at least 10% but not more than 50% by weight of the alloy.

Abstract: A sealing fixture in combination with a cap member provides a fluid-tight compression seal between an elastomeric septum and a tubular body. The septum is disposed transversely on a first end of the sealing fixture, which is of cylindrical configuration with an axial bore. A second end of the sealing fixture fits over the tubular body. The cap member covers the septum by being screwed down over a threaded portion of the outer wall of the sealing fixture. An aperture is provided in the cap member through which an injection device can be inserted to puncture the septum so as to deliver a quantity of fluid to, or to remove a quantity of fluid from, the tubular body via the bore in the sealing fixture. An outer wall portion of the sealing fixture adjacent the first end thereof is tapered inwardly to form a sharp junction with an inner wall portion of the sealing fixture. This inner wall portion adjacent the first end of the sealing fixture is parallel to the axis of the bore.

Abstract: Short bursts of ultrasonic energy are directed through a three-dimensional specimen to determine the spatial distribution of those structures within the specimen capable of affecting the waveform of the energy. Transducers are placed in spaced positions about the periphery of the specimen to measure the affected parameters (such as attenuation and delay time) of the energy as a result of passing through the specimen along paths between the spaced transducers. The output signals containing this transit time and energy absorption information are retained in a data storage device. Through conventional programming techniques, a computer processes the data and calculates a velocity or absorption profile for each path. The profiles are collectively used to reconstruct two-dimensional or three-dimensional images of the specimen.

Abstract: In a chromatography system of the type including an oven for the chromatographic column, and an electric heater for controllably heating the oven, an improved system is disclosed for controllably opening and closing the oven door to enable a fully controlled heat leak, thereby to stabilize the oven temperature at a desired set point. A signal, which is indicative by first or second conditions of an oven temperature above or below the set point, is generated. A heater power control responsive to one of the signal conditions can effect heating of the oven. A bi-directional door motor and actuator means is provided for opening and closing the oven door over a prescribed operating range, and this means is enabled to operate for a predetermined period upon the signal in its first or second condition departing from preset threshold values for a predetermined period, in consequence of which the opening or closing of the oven door is effected in incremental steps.