Abstract: A particle sensor operates in ambient air at an ambient air temperature and includes (a) a light source projecting a beam of light, (b) a light trap aligned with the beam of light and comprising at least one light-energy-absorbing surface at a surface temperature, (c) a nozzle flowing particle-entraining air through the beam of light, and (d) an opto-electrical system detecting light scattered by a particle. In the improvement, the sensor includes a cooling apparatus in heat transfer relationship to the surface and absorbing heat from such surface. The surface temperature is maintained at or below a value which substantially eliminates thermally-induced electro-optical disturbances in the sensor.

Abstract: A vibrator has (a) a housing including a wall forming a cavity, (b) a sleeve in the cavity, and (c) a piston received in the sleeve for reciprocating movement therein. In the improvement, the cavity has a boundary surface inside the housing and the vibrator includes an impact block interposed between the boundary surface and the sleeve. Such impact block is positionally retained in the cavity by the boundary surface and the sleeve.

Abstract: The cytogenetic chamber includes a chamber enclosure, a drying cavity in the enclosure, a door and a hand-insertion port through the door. A slide-supported, fixative-treated cell (prepared outside the chamber or in situ in the chamber) is in the drying area and air flows through the entirety of the drying area at a substantially uniform (and relatively low) flow rate. The fixative dries at substantially the same drying rate, irrespective of the location of the slide in the drying area. The invention is particularly useful for chromosome spreading and results in a significantly-increased percentage of metaphases having metaphase areas in the optimal range of 2,500 to 4,500 squared microns.

Abstract: A method for counting, by ranges of size, particles flowing through a particle sensor including the steps of flowing a particle through the sensor, thereby producing a voltage pulse which is sampled over a period of time. Sampling yields a plurality of voltage values which includes a latest value and a former value. The latest value is compared with the former value and when less than the former value, the method finds, in a table of threshold voltages, the size range for the particle. A counting bin corresponding to the size range for the particle is then incremented. The former value may be the value immediately preceding the latest value or it may be several "counts" prior to such latest value. The new particle sensor has an inlet, sensing volume, exhaust port, light collection system and an electronic system coupled to the light collection system. The electronic system is programmed to count particles, by size, in any of several unique ways.

Abstract: The cytogenetic chamber includes a chamber enclosure, a drying cavity in the enclosure, a door and a hand-insertion port through the door. A slide-supported, fixative-treated cell (prepared outside the chamber or in situ in the chamber) is in the drying area and air flows through the entirety of the drying area at a substantially uniform (and relatively low) flow rate. The fixative dries at substantially the same drying rate, irrespective of the location of the slide in the drying area. A related method is also disclosed. The invention is particularly useful for chromosome spreading and results in a significantly-increased percentage of metaphases having metaphase areas in the optimal range of 2,500 to 4,500 squared microns.

Abstract: Disclosed is a particle sensor of the type having (a) a light beam, (b) an air tube flowing a stream of air across the light beam at a volumetric flow rate, and (c) an air pump providing the stream of air through the tube, across the light beam and along an air flow path. In the improvement, the particle sensor includes a flow-controlling apparatus in series with the flow path for slightly trimming or adjusting the flow rate, i.e., the rate usually set at the factory before shipping. Such flow-controlling apparatus is selected from a group of apparatus including a choke valve (preferably an adjustable choke valve), a slip clutch, a speed-adjustable blower drive motor and a plurality of conduits. The conduits may have the same passage cross-sectional area and differing lengths, the same length and differing cross-sectional area or a combination of such conduits. A new method for assaying an airborne particle is also disclosed.

Abstract: A vibrator table apparatus includes a primary table member driven by at least two vibrators. The vibrator long axes are spaced from and angular to one another. The table member has a number of cylindrical holes formed through it. That is, the holes and "through-holes" and extend between the upper and lower surfaces of the table member. The total of the areas of the holes is in the range of 40% to 60% of the area defined by the perimeter edge of the table member and, most preferably, is about 50% of such area. The upper surface of the table member has a number of sockets formed in it for receiving respective standoff studs. A product support platform is coupled to the standoff studs and is in a spaced relationship to the upper surface.

Abstract: The new particle sensor is used for assaying particles and includes a light source comprising one or a plurality of light-emitting laser diodes. Light from each diode propagates along a flexible conduit or "light pipe," preferably a separate fiber optic strand. The sensor has a low voltage power supply and drives the diodes at 1-5 VDC. Light from one or bundled fiber optic strand(s) is focused by a focusing lens to provide an intense light beam for small-particle detection. For improved design flexibility, the light source may be mounted independently of the light beam long axis.

Abstract: An apparatus for attenuating sound in a HVAC system has an inlet mouth aria a tube downstream of the inlet mouth. In the improvement, the inlet mouth defines a surface of revolution formed by rotating a segment of an ellipse about the long axis aria at a fixed distance therefrom. The new apparatus has an air flow transition chamber which permits air flow to "normalize" after air enters the apparatus at its inlet end but before such air enters the inlet mouth. The apparatus also has a baffle between the entry portion and the apparatus outlet end and positioned to occlude the enclosed cavity between the interior tube and the outer housing. The apparatus thereby more effectively attenuates sound in the third octave band. Optionally, the apparatus (either alone or in combination with a VAV terminal unit) has exterior insulation for preventing moisture condensation and further reducing objectionable sound.

Abstract: The disclosed eddy-current separator has several new features. One includes a magnet assembly which is metal-sleeved for protecting the magnets from impact by particles or objects piercing the waste-carrying conveyor belt with which the separator is used. A low-rotating-speed epoxy-layered shell surrounds the sleeve for additional protection. A conveying extension carries ferrous "fines" from the conveyor into the receptacle used to collect waste from which non-ferrous material has been separated. Such extension permits such fines to be under the substantial influence of the magnet assembly over an arc well less than 180.degree.. The conveyor belt uses relatively-closely-spaced cleats of reduced height to reduce the "loading" of an individual cleat with potentially-piercing ferrous fines. A two pole magnet assembly may be used and/or a magnet assembly in which the magnet pole faces are curved for air gap reduction.

Abstract: A new method provides test equipment having a humidification capability. Such method includes the steps of fabricating equipment having (a) a chamber for stress-testing products placed therein, and (b) a cavity for receiving a module. The equipment is installed in a product test facility and used for stress-testing (by, e.g., "temperature cycling") a first group of products placed in the chamber. Later (perhaps several months or years later), the module is mounted in the cavity, a second group of products is placed in the chamber and humidity-controlled air is circulated across the second group of products. The new method is particularly useful for manufacturers or testers of products like electronic printed circuit boards initially requiring only a temperature-related testing capability but later needing to add humidity-related testing regimens.

Abstract: The disclosed eddy-current separator has several new features. One includes a magnet assembly which is metal-sleeved for protecting the magnets from impact by particles or objects piercing the waste-carrying conveyor belt with which the separator is used. A low-rotating-speed epoxy-layered shell surrounds the sleeve for additional protection. A conveying extension carries ferrous "fines" from the conveyor into the receptacle used to collect waste from which non-ferrous material has been separated. Such extension permits such fines to be under the substantial influence of the magnet assembly over an arc well less than 180.degree.. The conveyor belt uses relatively-closely-spaced cleats of reduced height to reduce the "loading" of an individual cleat with potentially-piercing ferrous fines. A two pole magnet assembly may be used and/or a magnet assembly in which the magnet pole faces are curved for air gap reduction.

Abstract: Disclosed is a particle sensor having a light beam with a beam long axis and an air flow tube with an inlet end and a particle exit mouth. In an aspect of the invention, the cross-sectional area of the flow passage at the inlet end is greater than the cross-sectional area of the exit mouth. This enlarged area dramatically reduces pressure drop along the tube. The exit mouth is in registry with the light beam and is elongate in a direction substantially parallel to the beam long axis. Thus, particles flowing through the mouth pass through the beam. In another aspect, the invention includes a centrifugal blower which is light in weight and which may be battery powered.

Abstract: A new method for analyzing an electrical waveform of the type portrayed on a graph includes the steps of selecting a waveform to be analyzed, establishing the boundary of a window-like area and generating a signal if the waveform is in a predetermined position with respect to the area. For example, a signal such as a failure signal is generated if the waveform is to be out of the area but, in fact, is in the area. The method also includes features for determining certain parameters, e.g., rise time, period and the like, for the waveform. The steps include selecting first and second points on the waveform and determining the time lapsed between points. Details regarding the structure of a new waveform analyzer are also disclosed.

Abstract: A method for entering data comprised of alpha, numeric and/or symbolic characters includes providing a plurality of hard keys, each of which is identified with two alpha characters. Such hard keys are preferably provided in a key matrix (not unlike a telephone key matrix) wherein all of the alpha characters of a particular alphabet are represented on such hard keys. Such method also includes providing two "display-type" soft keys, each for displaying an alpha character appearing on one of the hard keys and selected by actuating such key. A different alpha character is thereby displayed at each of the soft keys. That soft key displaying the alpha character desired to be entered is then actuated, thereby entering the displayed alpha character into the data field being edited. A new apparatus is also disclosed.

Abstract: The disclosure involves a variable air volume (VAV) terminal unit having an inlet collar, a box-like compartment connected to the collar and an insulation layer on the exterior surface of the compartment. The compartment is made of non-fibrous, rigid sheet-like material and an air stream flows through the compartment in contact with the sheet-like material and along a path spaced from the insulation layer. A method for making the variable air volume terminal unit involves steps including forming a plurality of flat, panel-like insulating components and securing a separate component to each of at least two compartment surfaces.

Abstract: A new method for analyzing an electrical waveform of the type portrayed on a graph includes the steps of selecting a waveform to be analyzed, establishing the boundary of a window-like area and generating a signal if the waveform is in a predetermined position with respect to the area. For example, a signal such as a failure signal is generated if the waveform is to be out of the area but, in fact, is in the area. The method also includes features for determining certain parameters, e.g., rise time, period and the like, for the waveform. The steps include selecting first and second points on the waveform and determining the time lapsed between points. Details regarding the structure of a new waveform analyzer are also disclosed.

Abstract: The disclosure involves a particle sensor having a mirror cavity unobstructed by masks and the like. A light detector is at the mirror secondary focal point and well outside the mirror cavity. A variation includes a beam splitter and a secondary light detector to improve detection of larger particles. A second embodiment includes a pair of elliptical mirrors offset along the light beam. Light reflected by the second mirror represents only changes in laser power and light scattered by gas molecules. The resulting signal is subtracted from that produced by the first mirror to obtain a relatively "clean" signal useful to assay very small particles.

Abstract: The invention is an improvement in a thermal stress screening system of the type using a single type of liquid for alternately transferring heat to and from the product. In the improvement, the product is confined in a single chamber during alternate heat transfer. That is, the system provides "one chamber" thermal stress screening. The system includes a plurality of tanks, one each for hot and cold liquid, and a heat exchanger associated with each tank so that the liquid in a tank is maintained at the proper temperature for stress screening. An improved method for thermally stress screening products, e.g., printed circuit boards, includes the steps of placing the product in a chamber, flowing cold liquid into the chamber, draining the cold liquid from the chamber and flowing hot liquid into the same chamber.

Abstract: The invention is an improvement in a carrier of the type used for testing circuit boards in an environmental test chamber. The improvement includes a plurality of frame-supported, spaced-apart shelves. Pairs of shelves are used to hold circuit boards being tested. The position of at least one shelf in such a pair is adjustable to select the proper dimension to support circuit boards of any of several particular sizes. In a highly preferred arrangement, shelves are arranged in two groups. At least one of the two or more shelves in each group is adjustable so that the carrier simultaneously accommodates circuit boards of differing sizes for test. Arrangements are shown whereby circuit boards of varying heights and/or lengths can be mounted in the carrier for simultaneous testing.