Abstract: Small glass bottles of unstable configuration are drop packed in several stages to fill a packing case capable of holding a relatively large number of such bottles. Separate slugs of articles are formed to fill predetermined portions of the case in a method which permits use of a conventional drop packer grid.

Abstract: A tap attachable to a spout of a container for decanting a liquid such as wine into bottles has a rotary valve housing and a valve body provided with a detachable handle, part of that valve body being a tubular spigot fitting into a transverse bore of the valve housing to fill a bottle aligned with that bore. The spigot, when withdrawn from the bore after removal of the tap from the spout and plugging of the latter, is receivable in an internally threaded plastic cap for forcing it into the neck of a freshly filled bottle; to unseal the bottle, a complementarily threaded extremity of the handle detached from the valve body is screwed into the cap for extracting same.

Abstract: For filling successive spouted bags with a beverage or like fluid product to a prescribed weight, a filling valve assembly and a cap remover assembly are immovably mounted side by side in a germfree chamber formed over a weighing platform. After the germfree chamber and the interior of a filling head forming a part of the filling valve assembly have been sterilized, a bag is placed on or over the weighing platform, with its capped spout caught by a spout carrier arm, which is supported on the weighing platform for both linear up-and-down motion and pivotal motion about a vertical axis. Following the removal of the cap from the spout by the cap remover assembly, the arm carries the spout to a position under the filling valve assembly and holds the spout against the filling head.

Abstract: The inserting station for a packing machine for inserting articles in boxes in layers comprises a plurality of lifting elements following the articles in the conveying direction. These lifting elements at least partly pass through the article conveyor means in order to successively raise the articles. The in each case raised lifting element forms a stop member for the following article. Each lifting element is shorter in the conveying direction than the extension of the article therein, which represents a measure for the overlap of the articles in a layer. In this way it is possible to position for forming a layer and overlap articles with an all-round flat or irregular edge.

Abstract: A bag making machine includes a generally vertically oriented forming element on which bags are formed in succession; a conveyor extending underneath the forming element and having a generally horizontal direction of advance, a first drive for intermittently advancing the conveyor, bag grasping tongs supported underneath th forming element below the conveyor, a second drive for moving the tongs upwardly through the conveyor to the forming element and for moving the tongs downwardly from the forming element through the conveyor, whereby the tongs draw a bag off the forming element and deposit the bag on the conveyor. There is further provided a third drive for moving the tongs in a direction having a component parallel to the direction of advance of the conveyor. The second and third drives are synchronized with one another and with the first drive for moving the tongs simultaneously upwardly and in the direction of advance of the conveyor during motion thereof.

Abstract: A packing apparatus, in particular for provisions in a squeezed style package, is provided comprising a hopper to supply a predetermined amount of the provisions into a synthetic resin film tube, a heat-seal and fusion cutting device disposed beneath the hopper to heat seal and cut the tube, a squeezing device disposed beneath the heat-seal and cutting device comprising two pairs of horizontal parallel bars disposed at right angles such that the confronting bars of each of the pairs are adapted to be moved towards and away from each other, a taping device disposed near the squeezing device and adapted to tape around the squeezed portion of the packing with an adhesive tape, a cutting device to sever the adhesive tape after taping, and a driving means to actuate the various components in a synthronized manner.

Abstract: A rotative plant material squeezing and shear force cell rupturing machine having a plurality of rollers, each with lobes and grooves intermeshing with the lobes and grooves of other rollers; the lobes and grooves may be either radial or axial irregularities of the rollers. By adjustment of roller spacing material processing may be varied from slight squeezing and shear fracture of the cells to almost total pulverization of the plant material.

Abstract: A multipurpose, wheeled implement having a frame mounted platform configured to secure a lawnmower in proper disposition for utilizing the power from the lawnmower engine for driving rotary working tools carried by the implement frame. A projection of the implement frame is configured to receive thereover in telescoped relationship a socket shaped mounting structure for the rotary tool to facilitate quick interchangeability of the tools. One form of the tool disclosed is a rotary tiller and another embodiment is a snow blower.

Abstract: A self-contained battery-energized, cordless lawn edger. This device includes a frame supported on at least three wheels which frame securely carries, for example, one or more rechargeable wet-cell batteries as well as a pivotally mounted sub-assembly having a heavy-duty series wound drive motor, a rigid edger blade mounted on the drive motor output shaft and a blade guard. Recharging may be accomplished by interconnection to a conventional automotive charging system, a battery charger, or to a 115 V.A.C. power source. The blade is positioned to rotate in a plane generally perpendicular to the ground. A blade positioning lever is pivotably attached to the main guide handle for vertical positioning of the blade. A drive motor on-off switch attached to the handles is also provided. A removable cover may also be provided for protecting the battery energizers. One or more of the wheels may also include drive means.

Abstract: An improved power lawn rake has a rotor provided with a plurality of ground-engaging spring tines. The dead leaves and other debris are carried by the rotor along the curved forward wall of a deflector box, and are discharged between the deflector box and a front channel and into a molded bin. The bin is removably mounted on respective side housings of the main frame of the power lawn rake. Ground-engaging forward wheels are vertically adjustable on brackets mounted on the front channel. The wheels are nested within externally-accessible recesses formed in the bin. A driving motor is cantilever mounted on one of the side housings of the frame for driving the rotor. The drive is through gearing (in a gear case secured to the motor housing) and through a belt and pulley arrangement accessible through a cover plate removably secured to the side housing.

Abstract: An agricultural attachment for harvesting agricultural products arranged in rows, such as corn and the like, has a frame, a plurality of product drawing elements, and a plurality of hingedly mounted dividing elements associated with the product drawing elements so as to form together with the latter product drawing passages, wherein each of the drawing elements have two parts which are articulately connected with one another so that they are pivotable relative to one another to assume a position in which they have a tipped roof shape and are fixable in this position.

Abstract: Hinged tables for swathers usually are provided with individual knife sections and the center section of this knife is difficult to drive. This invention eliminates the necessity for a center section drive by using a two section knife on a three section table with each knife section extending through one wing section and part of the center section. The knives are driven from the outer ends and are allowed to flex over the hinge area. The wing sections are provided with rigid guard bars and a flexible section of guard bars secured to the inner end of the rigid guard bar and is secured by the other end to the center of the center section by means of a swivel or sliding connection.

Abstract: A baler for forming cylindrical bales is comprised of a bale forming chamber having a downwardly facing opening. A pickup is pivotably mounted to the frame of the baler for movement through a range of vertical positions, and transversely extends between the sidewalls of the baler below the opening. Flare sheets are mounted on each side of the pickup for aiding in feeding and guiding of crop into the bale forming chamber by the pickup. The pickup is mounted pivotably to the frame of the baler adjacent to the rear of the opening. Each flare sheet is mounted to the frame of the baler adjacent to the front of the opening in a guide slot which permits the flare sheet to be pivotably and slidably moved back and forth therein. The flare sheets and the pickup are mounted together for conjoint movement through the range of positions by mounting each flare sheet at respective ends of the pickup reel.

Abstract: A rake wheel attachment for a harvesting machine such as a cylindrical baler comprises a wheel for engaging and moving crop material laterally of the path of the baler. The wheel is rotatably supported by a wheel support and is pivotably mounted on an arm attached to the machine about the axis of the arm which is generally perpendicular to the axis of the rotation. The rake wheel is biased into an operative position by a spring connected between the wheel support and the arm. The spring is yieldable to permit the wheel to pivot about the arm axis responsive to the engagement of the wheel with a rock or other foreign bodies.

Abstract: In the manufacture of a lightguide fiber cable (21) in which a lightguide fiber core (32) is loosely disposed in a composite sheath 40 it is important to control the ratio of the lengths of the core and sheath. A core which is shorter than the sheath and which follows a shortened path on a reel may be unduly strained when the cable is installed in the field. This problem is overcome by coupling the core to the sheath by a system (25) which includes a constant speed linear capstan (146) and a relatively large variable speed sheave (150) that is positioned between the linear capstan and a takeup reel (154). The coupling of the core to the sheath is accomplished on the sheave after the sheath is elongated between the linear capstan and the sheave. The coupling and the elongation cooperate to compensate for the inherent shortfall in core length which otherwise would occur when the cable is wound on a reel.

Abstract: A pneumatic yarn splicing apparatus for splicing spun yarns including two nozzle pipes for untwisting and attracting yarn ends to be spliced and a yarn splicing member having a yarn splicing hole which is disposed between the nozzle pipes. The nozzle pipes have opening areas reduced with respect to the diameter of the nozzle pipe to increase the speed of flow of the suction stream of air.

Abstract: A double twisting machine for winding a wire around a take-up roll has two motors for directly and separately driving each end of a flyer thereby eliminating the need for a driving shaft, driving pulleys and timing belts which substantially reduces the amount of noise generated by the machine and reduces its overall size.

Abstract: A multi-unit telecommunication cable is disclosed in which the twisted wire pairs of the unit are presented adjacent the conductive cable sheath at irregularly spaced locations. The cable may be made by modulating the amplitude and/or frequency of the oscillations of the faceplate employed in twisting the wire pairs together in forming the cable units.

Abstract: The apparatus includes a control between the electromagnetic tension control and the yarn supply package to prevent the yarn coming off the package from rotating in a full balloon path and consequently prevent entanglement of the yarn in the yarn guides to a yarn consuming machine. The balloon control basically employs a bar member under which the yarn passes as it is delivered to a yarn guide tube. The bar member prevents the yarn from rotating as it is taken off over-end from the yarn package thereby alleviating the possibility of yarn entanglement at the yarn tube.

Abstract: A direct current electromagnetic disc type tension control which periodically has alternating current superimposed on the direct current circuit to allow the electromagnet to vibrate the tension discs in order to break the contact between the tension discs and between the tension discs and the electromagnet to lower the resistance to rotation of the discs.

Abstract: The airflow from the compressor of a gas turbine engine into the combustion chamber or chambers principally comprises combustion air which enters the upstream end of the combustion chamber and dilution air which enters the combustion chamber at some point downstream of the combustion chamber inlet, the combustion air being made up of primary and secondary air entering the combustion chamber primary and secondary zones.In order to cope with the control of emissions from the combustion chambers, it is desirable to control the combustion air fuel ratio over the engine operating range by controlling air mass flow to the combustion and dilution zones of the combustion chamber. The invention proposes that this control can be achieved by providing a variable rate diffuser upstream of the primary, secondary and dilution air inlets, the variable rate diffuser comprising vortex generator having an associated variable air bleed.

Abstract: A cooled wall structure for a gas turbine engine comprises a perforated and an inner wall in which the walls are capable of relative movement to cope with the thermal strains experienced by the combustion chamber during operation of the engine. The inner wall comprises a number of wall elements attached to the outer wall in the manner of overlapping tiles. Each wall element is immovably secured to the outer wall at the mid-point of its downstream end and the sides of each wall element are movably attached to the outer wall adjacent the sides of the downstream end of the wall element.The upstream end of each wall element is located between the outer wall and an adjacent flow in either an upstream or a downstream direction between the walls.The wall elements can have a plurality of raised lands to increase the surface area of the elements and to protect the incoming cooling air against the cross-flow of cooling air already flowing in the wall structure.

Abstract: The present invention relates to an electric regenerator for use with a gas turbine. The gas turbine must have at least one compressor stage and one combustion stage and an interconnecting duct. The regenerator comprises an electrical heating element located within the duct. The heating element is supplied with electrical power generated from exhaust gas exiting from the combustion stage, wherein the temperature of the heating element is greater than the temperature of the compressed gas flowing in the duct.

Abstract: An aircraft propulsion assembly in which a prime mover drives a rotating air stream generating element, situated in a generally circular housing that supports a ring shaped stator in which a number of circumferentially spaced slots are defined. An elongate nozzle is axially aligned with the rotating element, which nozzle on the forward end in cooperation with the housing defines a circular plenum chamber that is in communication with the slots. The plenum chamber on an inner portion thereof cooperates with the stator to define a circular aperture. A first portion of the air stream generated by the rotating element flows rearwardly through the nozzle and a second portion through the slots in to the plenum chamber to be compressed. The compressed air excapes from the plenum chamber through the circular aperture, and due to the Coanda effect flows along the interior surface of the nozzle as a cylindrical sheath at a higher velocity than the first portion of the air stream flowing rearwardly through the nozzle.

Abstract: A compound propulsor for powering a vehicle, such as an aircraft. A compound propulsor includes a core gas turbine engine, a fan encased within a cowl, at least one propeller, and drive means for distributing a portion of the power produced by the core engine to the fan and another portion to the propeller. Preferably, the compound propulsor also includes variable geometry inlet guide vanes for varying the portions of power distributed to the fan and propeller.

Abstract: A vehicle engine accessory drive system is disclosed including a hydraulic fan motor (M) and a power steering gear mechanism (SG) in series flow relationship. The system includes a variable displacement power steering pump assembly (P) which is the sole source of fluid for the system, and includes a variable displacement pumping element (PE) and a displacement control valve (CV). The displacement control valve includes a pilot valve (35) which is responsive to the demand for cooling to vary the fluid pressure in a signal chamber (63). The displacement control valve is operable to communicate a control fluid pressure to a stroking cylinder (SC) to control the fluid delivery rate of the pumping element. At a first relatively lower temperature, the displacement control valve maintains the fluid delivery rate of the pumping element at Z, and at a second relatively higher temperature, to maintain the fluid delivery rate at X.

Abstract: A construction of a variable volume chamber that allows cycling of a working fluid to occur substantially isothermally is disclosed. The present invention provides a fixed, rigid heat conductive element within the chamber. The heat conductive element has a surface area which is large relative to that of the chamber itself. The volume of the chamber is varied by a mechanism which meshes with the heat conductive element to minimize dead volume. As a result the heat conductive element absorbs and returns heat energy to and from the working fluid in an efficient fashion, resulting in a high degree of isothermalization of the working fluid.

Abstract: A brake booster for vehicles having a vehicle body with a brake pedal, including a tubular housing forming a seat portion having an inner wall, a brake master cylinder coaxially adjacent to an output side of said tubular housing and having a piston and a cylinder body, a cylinder integrally formed with said cylinder body of said brake master cylinder and extending to the inner wall of the seat portion within the tubular housing for attaching the tubular housing to the vehicle body, a flange member positioned adjacent said inner wall of said seat portion and formed on an end portion of an outer circumference portion of said cylinder, a first movable member axially dividing a space formed on an outer circumference portion of the cylinder by the tubular housing and the cylinder and movable to the output side due to a pressure difference generated therebetween both sides, a second movable member slidably inserted into the cylinder and integrally movable with the first movable member and including an end portion o

Abstract: A solar pond power plant has a solar pond with a heat storage layer for storing heat absorbed from solar radiation incident on the pond, and a low-temperature, closed Rankine-cycle turbogenerator operating on heat extracted from the heat storage layer. The turbogenerator has a generating capacity of Q.sub.I watts/m.sup.2 of pond area, this capacity being in excess of Q.sub.e watts/m.sup.2 of pond area where Q.sub.e is the net electrical energy that can be generated by the turbogenerator when heat is extracted from the heat storage layer at substantially the same average rate at which heat is absorbed by the layer. According to the invention, the generating capacity Q.sub.I of the turbogenerator is in the range 2-10 times Q.sub.e, whereby the solar pond power plant can be utilized for peak power requirements of a regional electrical generating system.

Abstract: A fluid-operated refrigerating machine for developing extremely low temperature by using a displacer reciprocatable within a refrigeration cylinder and a fluid-operated piston solidly connected to the displacer. A mechanical converter which converts a reciprocating motion into a rotary motion is operatively connected to the piston to limit the stroke of the piston thereby to prevent the displacer from its collision with the end walls of the refrigeration cylinder and ensure smooth operation of the displacer. For controlling gas to and from the refrigeration cylinder as well as to and from the driving chamber of the piston, a single rotary valve driven by a motor is used. In an embodiment, the rotary valve is operatively connected to the converter and thus the displacer is not only under fluid-operation but also is mechanically operated by the motor through the converter.

Abstract: A cryopump installation in which a novel cryopump 20 maintains a work chamber 12 at continuous high vacuum while periodically evacuating a load lock 14 in order to allow transfer of material from the load lock 14 to the work chamber 12 without disruption of the work chamber environment. The cryopump has pumping ports 46 positioned on the radiation shield 50 in order to pump plenum 72 to a high vacuum. Load lock gases enter the cryopump through port 46 and are condensed and adsorbed by the radiation shield 50 and second stage cryopanel 54.

Abstract: Air conditioning systems and methods for use in multi-unit buildings wherein an air conditioning system is provided with an air handling unit which includes a water cooled first heat absorbing means, a mechanical refrigerant cooled second heat absorbing means, and means for circulating air successively through the first and second heat absorbing means. Means is provided for circulating cooling water successively through a first heat absorbing means and a refrigerant condensing heat exchanger in series relation with a flow rate through at least the first heat absorbing means substantially independent of the operating condition of the refrigerant compressor and the refrigerant condensing heat exchanger.

Abstract: The cooling performance of an air conditioning apparatus is controlled by a selective combination of three methods of regulation, in accordance with the required degree of cooling. A first stage of regulation controls the volume of air delivered by a fan 6, a second stage controls the amount of refrigerant flowing through a pressure reduction means 7, and a third stage controls the amount of refrigerant circulating in a compressor feedback circuit 9. Any one of or combination of these three controls may be employed in accordance with the prevailing temperature condition and the required cooling performance.

Abstract: A shipping container for safely maintaining contents at stabilized temperature during transit has a first insert arranged to be removably, frictionally fit between opposed side walls and formed to accommodate vials and provides storage space for packaged coolant and bottles in selected arrangement, a second insert arranged for frictional engagement with opposed side walls and formed to accommodate bottles and access formations in the side walls engaged by the first insert to permit ready removal.

Abstract: The invention relates to a washing machine which comprises a casing (1) having a washing-liquid container (2) and a cylindrical washing drum (3) rotatably arranged in the container. The washing drum is driven by a single, brushless a.c.motor, to which energy is supplied from an inverter (41), so that the washing machine may be driven at a desired, alternative number of revolutions/min, which are preprogrammed and within an extended range of revolutions/min.

Abstract: A lock assembly including a novel retaining strap for securing a lock cylinder within the assembly. The lock assembly is designed so that one of two different degrees of bolt extension can be chosen during assembly of the device. In addition the assembly incorporates a dowel pin to increase the strength of the joint between the lock bolt and a lock bolt extension connected to the lockbolt.

Abstract: A locking assembly is provided that can be placed over a push-button keyboard to prevent unauthorized use. The entire keyboard is covered and a tumbler-activating key is inserted externally, rotated and withdrawn. When installed on a telephone, the device allow incoming calls to be received. If pried off of the keyboard to allow emergency use, no major damage would be inflicted to the keys, but the assembly could not be reinstalled without unlocking.

Abstract: A cylinder lock mechanism includes a tubular barrel, a lock cylinder rotatable in the barrel, tumblers longitudinally and reciprocally movable within the cylinder, a cap on a front end of the barrel and having a key opening therethrough, a facing member interposed between the cap and the cylinder and having an opening registering with the cap opening, a spacer interposed between the facing member and the cylinder and having an opening registering with the cap opening, such openings when in registry receiving a key for insertion thereof into engagement with the tumblers, an engagement member extending transversely of the cylinder for engagement with the tumblers and laterally movable to and from the tumblers, a locking member extending longitudinally of the cylinder for engagement with the engagement member and laterally movable to and from the tumblers, structure on the cylinder and the barrel respectively for engaging the locking member therealong for locking purposes, structure on the tumblers for engaging

Abstract: A metal can top rests on a tool seat for the purpose of riveting a pull-up ring to the metal can top. Riveting takes place with the aid of a dolly which moves back and forth relative to the tool seat. Transmitters are arranged in the tool seat to check that no foreign objects are present in it. Transmitters sense the movement of the dolly past a reference level as it moves towards the tool seat. In the riveting position the dolly presses the metal can top and associated pull-up ring against the tool seat, whereby the pull-up ring actuates a sensing pin and moves it to an indicating position which is sensed by a transmitter. The signals from the respective transmitters are received by a delay and control device.

Abstract: One embodiment of an invention providing am inprovement upon a U-bolt bender is disclosed. The bender has a clamp for clamping a workpiece thereto and a slide for advancing the workpiece along a path. The improvement comprises a die and rollers for urging an intermediate portion of the workpiece against a forward surface of the die and for urging end portion of the workpiece respectively against sides of the die adjacent to the forward surface. The bender carries the rollers and the slide carries the die and brings the workpiece into engagement with the rollers by advancing the workpiece along the path. The sides of the die converge together and extend away from the forward surface such that as the slide brings the workpiece into engagement with the roller, the rollers urge the intermediate portion of the workpiece against the forward surface and urge the end portions of the workpiece respectively against the sides of the die, the slide meanwhile causing the clamp to clamp the workpiece to the die.

Abstract: An apparatus for substantially eliminating deflection of cantilevered work roll shafts and work rolls of a cantilevered type rolling mill comprising adjustable work roll support rollers which rotatably brace work rolls at points approximately 180 angular degrees from the metal stock and work roll contact area.

Abstract: A pipe bending machine (10) is described which incorporates a bending die (14) which supports coated pipe during bending without damaging the coating. In one embodiment, the bending die (14) employs a conventional die (30) with a plurality of longitudinal rods (40, 42, 44) spaced from the inner surface of the die (30) and in pipe confronting relation. When the pipe is urged against the bending die in the machine, the rods precompress the material thereunder for transmitting the bending forces. The rods (40, 42, 44) are spaced a sufficient distance from each other in the transverse direction about the inner surface of the die to permit the material to flow outward therebetween to reduce the stresses in the coating. In a second embodiment, a plurality of transversely extending rings (62, 64 66) are positioned on the inner surface of a conventional die (30) which further act to support bending forces without damage to the coating.

Abstract: Methods of necking-in and flanging tubular can bodies having body walls of constant thickness. A pilot die initially inserted into the tubular can body reverses its direction during the necking-in operation with respect to the motion of a ring die member that contacts the exterior surface of the tubular can body member. This concurrent reverse movement of the two forming dies eliminates wrinkles in the necked-in region and produces a container body with increased columnar strength. Repetitive use of the method produces containers with two or three necked-in portions. A method is also disclosed for relubricating the necked-in area of the tubular can body between the successive necking stations.

Abstract: A transducer system that provides accurate measurements of a physical variable such as pressure for any one of a number of different transducers. Each transducer includes special calibration indicators for identifying any inaccuracies in its output signal, and monitoring and correcting circuitry is selectively attachable to any one of the transducers, to read the calibration indicators and apropriately adjust the transducer's output signal, thereby correcting for the identified inaccuracies.

Abstract: A self-compensating centrifuge arm for use in a centrifuge system having drive means for causing rotation of the centrifuge arm around a center of rotation. The centrifuge arm comprises two elongated members, the first elongated member being attached to the drive means for rotation therewith and extending outwardly from the center of rotation a first predetermined length in a first direction to a terminal end portion. The second elongated member has a second predetermined length and a first end which is attached to the first elongated member at the terminal end portion thereof. The second elongated member extends generally parallel to the first elongated member through the center of rotation without being affixed to the drive means.

Abstract: Apparatus for testing abrasive wear on a surface of a sample. Flowable abrasive material is fed from a barrel against the surface. The sample is mounted reciprocally in the direction of feeding of the material, and urged by a force opposing that of the material thereon. The rate of feeding is controlled to maintain a gap between the end of the barrel and the sample so that the material flows continuously through the gap.

Abstract: A metal-oxide semiconductor, which is heated to different temperatures, is used in conjunction with an electronic circuit for reducing false alarms caused by spurious gases in gas warning installations and for determining the composition of a gas mixture. The temperature of the metal-oxide semiconductor, after reaching a predetermined value (T), is altered by an amount (.DELTA.T) either towards the positive or negative side or towards both the positive and negative side, respectively. The thus caused change in the conductivity of the metal-oxide semiconductor is evaluated in a comparator and in circuits for the different peak values of the gas components.

Abstract: To measure the concentration of molecules adsorbed on metal or insulator surfaces as well as their bonding to the surface and their mutual interaction, a vibrational spectroscopy method is proposed in which the infrared absorption is modulated using a first order Stark shift of the adsorbed molecule vibrational frequency. A sample surface in a high vacuum or at atmospheric pressure is illuminated by infrared radiation from a tunable diode laser an reflected radiation is detected by an infrared sensor. A high intensity electric field normal to the surface is amplitude modulated at a given frequency and the synchronous modulation of the reflected light is measured while varying the wavelength to obtain the spectra of vibrational absorption.

Abstract: The invention concerns the detection of contaminant in a stream of gas. Pious methods have either been insufficiently sensitive or have been slow and needed skilled operatives. The present invention allows speedy operation with relatively unskilled operatives. A piezo electrical crystal oscillator (1) is allowed to oscillate for a known period of time and the number of oscillations is counted. For a known time the crystal is exposed to contaminant, and is then allowed to oscillate again for the same period of time as before and the oscillations again counted. The difference in number of oscillations is a measure of the mass of contaminant deposited on the crystal (1). The period of oscillation of the first crystal is determined by a second matched crystal oscillator (2) in which the crystal is exposed to the same environment but not in contaminant. The apparatus has the advantage of being self-zeroing, and the exposed crystal (1) does not need cleaning after each use.

Abstract: This system is a combination of two techniques which are used together effectively combining their features. One technique is an absolute measurement based on mass accumulation rate and used primarily for calibration purposes. The mass accumulation rate on a filter, when divided by the flow rate of the medium through this apparatus, yields the droplet density. The second technique is a differential measurement with two adjacent sampling inlets, one is unrestricted while the other is inertially filtered to eliminate water droplets. The two flow streams in the differential system are cyclically sampled and the combined flow passes a heated wire grid designed to evaporate droplets encountered. The resulting oscillating signal (with DC component) is fed into a lock-in amplifier whose output is the rms value of the difference signal. The vapor component is thereby nearly eliminated and the signal is processed by the phase-locked signal-to-reference detection technique which produces very high sensitivity.