Abstract: A traction assembly of a work machine having (i) a differential housing having an axle passageway extending therethrough and (ii) an axle positioned within the axle passageway is disclosed. The traction assembly includes a gear mechanically coupled to the axle. The gear includes (i) an outer peripheral surface having a plurality of sensor teeth defined therein, (ii) a first shoulder extending in a first lateral direction, and (iii) a second shoulder extending in a second direction. The traction assembly also includes a bearing assembly attached to the differential housing, wherein (i) the bearing assembly includes a first bearing member and a second bearing member, (ii) the gear is interposed between the first bearing member and the second bearing member, (iii) the first shoulder of the gear contacts a first journal surface of the first bearing member, and (iv) the second shoulder of the gear contacts a second journal surface of the second bearing member.

Abstract: A contactless position sensor includes a Hall effect cell and a magnetic circuit formed by a permanent magnet and two pole pieces. The magnet and the cell are juxtaposed between the pole pieces. The pole pieces have active surfaces opposite the cell with respect to the magnet. This layout makes it possible to directly obtain an output signal proportional to the distance separating the active surfaces from the target.

Abstract: A hand-operated accelerator device includes a handgrip speed controlling actuator sleeved rotatably on a handlebar. A speed controlling signal emitting member has an elongated chamber therein with an opened guiding slot. A shifting member is slidably received in the elongated chamber, and has two magnets spaced apart from each other, and a protruding member extending outwardly of the guiding slot to move the shifting member in the chamber upon rotation of the actuator. A hall-effect generator extends transversely between the magnets so as to generate a voltage signal to be received by a circuit board when the shifting member is moved in order to convert the voltage signal into a control signal for controlling revolutions of an electric drive mechanism of an electric-powered bicycle. A spring is disposed to bias the shifting member in a longitudinal direction.

Abstract: A sensor has a rotor mounted on a throttle shaft, permanent magnets mounted on an end of the rotor and rotatable together with the rotor and the throttle shaft, a Hall-effect element fixed on a rotational axis of the magnets for outputting an electric signal corresponding to the direction of the magnetic field, and a circuit member for compensating the temperature characteristics of the magnets and the Hall-effect element and for driving the Hall-effect element and processing the output from the Hall-effect element. A circuit chamber of the sensor is filled with silicon gel to add heat capacity to the circuit member. A resin member having notches around a periphery thereof is disposed in a connecting portion of the rotor at which the rotor is connected to the throttle shaft to block heat conduction from the shaft toward the magnets.

Abstract: A lateral Hall element includes a substrate, a first-conductivity type active layer formed on the substrate, a first second-conductivity type semiconductor layer formed to surround the first-conductivity type active layer and formed to a depth to reach the substrate, a pair of first first-conductivity type semiconductor layers of high impurity concentration selectively formed with a preset distance apart from each other on the surface of the first-conductivity type active layer, current supply electrodes respectively formed on the pair of first first-conductivity type semiconductor layers, a pair of second first-conductivity type semiconductor layers of high impurity concentration formed with a preset distance apart from each other on the surface of the first-conductivity type active layer in position different from the first first-conductivity type semiconductor layers, sensor electrodes respectively formed on the pair of second first-conductivity type semiconductor layers, and a plurality of second second-c

Abstract: A vertical Hall element is formed within the epitaxial layer of a semiconductor and isolated from other components by a P type isolation diffusion. A position defining diffusion is used to accurately locate a plurality of openings within the position defining diffusion where contact diffusions are made. The position defining diffusion is made simultaneously with the base diffusion for transistors within the integrated circuit and the contact diffusions are made simultaneously with the emitter diffusion of transistors within the integrated circuit. Five contact diffusions are provided on the upper surface of the epitaxial layer and generally aligned within the region defined as the Hall element by the isolation diffusions. The center contact is used to provide electrical current flowing through the Hall effect element. Electrical current is split and flows to the two end contact diffusions.

Abstract: A controller for a Hall effect sensor includes a sensor section including a Hall effect sensor with a hysteresis set in the output electric signal characteristic with respect to the magnetic flux density, a power supply section for supplying a source power to the Hall effect sensor, and a signal processor for processing a signal output from the sensor section. The power supply section supplies power with a voltage, which is varied cyclically in a predetermined range and is increased gradually, to the Hall effect sensor.

Abstract: A sensor for measuring the swing of a cable or load includes a crown which creates a stable magnetic field, and a fixed portion for detecting movement of the crown, and the cable or load to which the crown is attached. The crown is secured to the cable and includes a series of permanent magnets disposed radially between an inner magnetic ring and an outer magnetic ring. The fixed portion includes measuring elements secured to a support, and defines a measuring space within which the crown can move.

Abstract: An acceleration sensor has a casing, a deflection spring arranged in the casing and having one end fixed to the casing and a free end, a Hall element, at least one sensor element attached to the free end of the spring and being in active connection with the all element, and a plate having a recess. The deflection spring together with the sensor element is arranged in the recess of the plate, and a hybrid circuit is provided with the Hall element and located on the plate.

Abstract: A signal generator for generating an electrical signal which varies in accordance with movement of an actuating member includes a plunger slidable mounted within a housing which carries a pair of permanent magnets for generating a magnetic field to be applied to a hall effect generator. As the plunger is moved relative to the hall effect generator, the magnets are also moved relative to the hall effect generator, thereby varying the magnetic field applied thereto. Accordingly, a variable output signal is generated as a function of the position of the input member.

Abstract: A sensor for automatically triggering safety devices in motor vehicles has a housing a having a recess, a body arranged in the housing so as to serve as a seismic mass and to trigger a control signal when a predetermined threshold value is exceeded, a permanent magnet enclosed by a region of magnetically nonconductive material, a Hall element arranged in the body in working connection with the permanent magnet and comprising magnetically conducting material. The Hall element substantially evaluates magnetic flux lines running parallel to a polarization direction of the permanent magnet, so that the Hall element evaluates the magnetic flux lines running parallel to the polarization direction of the permanent magnet in a basic position, and evaluates the magnetic flux lines running in an opposite direction in a tilting position.

Abstract: An integral pressure sensor for a pressurized vessel, including a housing, a core element, a seal and a spring. This combination is disposed on the interior of the pressurized vessel. The core element is preferably a magnetic element or a steel ball which moves in the housing under the effect of the vessel pressure, and the chamber or housing pressure. The spring and seal combination together with the core element, function to trap a specified volume of the pressurized medium in the chamber when the vessel is initially pressurized. When the pressurized vessel leaks, the trapped pressure within the chamber exceeds the vessel pressure thereby causing the core element to move. The position or presence of the core element is detected using a detecting device such as a Hall-effect device or another magnetic device.

Abstract: A magnetic field sensor for an acceleration sensor including a cantilever beam having a free end to which a permanent magnet is attached. A pair of the magnetic sensors, each consisting of a barber-pole type magnetoresistive sensing element, are arranged opposite to and symmetrically. The cantilever is bent and the magnet is moved according to an acceleration, which is detected as outputs from the magnetoresistive sensing elements.

Abstract: A damping arrangement for a deflectable beam accelerometer where the deflectable end of the beam is spaced from a stationary member. A drop of self contained viscous material extends between the deflectable end and the stationary member to dampen movement of the deflectable end.

Abstract: An acceleration sensor essentially consists of a cantilevered laterally bending beam arranged in a housing. Because of its mass inertia the bending beam is deflectable relative to the sensor housing in the plane of the acceleration to be measured. The bending beam has the design of a thin resilient strip which is wide relative to its thickness and is made of amorphous metal. The bending beam may have a one-layer or a multi-layer structure. In case of a multi-layer structure, the friction between the individual strips, causes the vibration to be damped. A small air gap between the walls of a closed housing and the bending beam additionally brings about an air damping of the bending beam's vibrations.

Abstract: A non-invasive system and method is provided for the inspection of check valves which combines acoustic and magnetic techniques. The acoustic and magnetic techniques are used to measure check valve disk motion and internal impacts or vibrations resulting from the disk motion.

Abstract: A force sensor has a hollow flexible body with a fixed end and a free end. The force to be measured is applied perpendicular to the axis of the flexible body by a link coupled to the free end. A rigid gauge rod is connected to the free end of the flexible body and extends through the interior of the flexible body. The rod carries on its free end a permanent magnet which is near a Hall-effect sensor which is fixed to the fixed end of the body. The flexible body has a relatively low bending stiffness at its free end (in the area of force application) and an increasing bending stiffness towards its fixed end. The flexible body has a relatively low bending stiffness in the direction of force application and a higher bending stiffness in a perpendicular direction. The permanent magnet is arranged so that its poles are aligned parallel to the direction of force application.

Abstract: An acceleration sensor including a cantilever beam having a free end to which a permanent magnet is attached. A pair of magnetic sensors, each comprising a barber-pole type magnetoresistive sensing element, is arranged in symmetrically spaced and opposed relationship and in a common plane extending parallel to the magnetic flux of the permanent magnet with respect to respective, opposite sides of the magnet. The cantilever is bent and the magnet is moved accordingly in response to an acceleration force, which is detected as outputs from the magnetoresistive sensing elements.

Abstract: An acceleration pickup has a housing of a diamagnetic or paramagnetic material enclosing a ferromagnetic ball acting as seismic mass. The ball is held in a starting position on the bottom of the housing by means of a magnetic field generated by a permanent magnet or an electromagnet. By means of four induction sensitive sensors such as for example Hall effect sensors arranged opposite each other on the circumference of the housing, the momentary value and direction of acceleration component acting on the pickup is determined. The acceleration pickup is simple in construction and cost effective in manufacture and is easily adjustable to different applications.

Abstract: A sensing device which is suitable for use as a decelerometer comprises a magnetic field producing element and a Hall effect sensor element with one of the elements supported for movement relative to the other. The arrangement is such that when the device undergoes acceleration or deceleration the support allows relative movement between the elements so that the sensor element produces an output indicative of the change in field the sensor element detects from the field producing element due to the relative movement between the elements to thereby provide an indication of acceleration or deceleration of the device. The output of the sensor is connected to a differential amplifier, and the output of the amplifier is connected to a transistor in parallel with a capacitor. When the device undergoes deceleration, the output signal of the sensor increases, causing the output voltage of the differential amplifier to decrease, which in turn causes the voltage across the capacitor to discharge.

Abstract: A tool positioning system comprises a discontinuity detection means, such as an eddy current system, for detecting a discontinuity within a workpiece resulting from a joint between a first piece of material relative to a second piece of material, the discontinuity being detected from the back side of the second piece of material. The discontinuity is detected at a plurality of points by translating an eddy current probe over the back side of the second piece of material, the individual points thereafter being utilized to compute line elements that define the joint between the first and second pieces of material in a continuous fashion over the surface of the second piece of material. Thereafter a tool, such as a laser welding tool, is guided along the computed position along the backside of the second piece of material such that the first and second pieces of material are welded together along the joint.

Abstract: An indicator for the rate of volumetric fluid flow includes a housing having a fluid passageway therein and a rotor contained in the housing in a position so as to be rotated by fluid flowing through said passageway. The indicator also includes a Hall effect transducer positioned outside the housing, responsive to the rotation of the rotor. The transducer produces an output signal corresponding to the rate of rotation of the rotor, and thus to the rate of fluid flow through the housing passageway. Preferably, the rotor is a paddle wheel disposed on an axle in the housing. The axle and thus the paddle wheel are retained in the housing by entrapment against a removable housing cover. The housing is otherwise mechanically imperforate to any connection between the rotor and the transducer.

Abstract: The acceleration sensor consists substantially of a leaf spring (12) with an eddy current disk (13), which is arranged at its free end as an inertia mass, and an eddy current brake with magnets which are polarized in opposite directions (16, 17), and a flux conducting piece consisting of low reluctance iron. The latter serves the purpose of oscillation damping of the spring-mass system formed by the leaf spring (12) and eddy current disk (13). By means of a sensor magnet (19) and a Hall element (20), the lift of the inertia mass is transformed into output voltage which is proportional to the acceleration. Such an acceleration sensor is installed in a motor vehicle, for example, and serves to trigger safety devices such as belt tighteners. It has the advantage that the frequency response is only slightly dependent upon temperature and is very simply and compactly constructed.

Abstract: An actuator system for positioning a flight control surface on an aircraft in which a primary braking device provides a continuous braking action to the actuator screw shaft by means of a load bearing disc brake wheel and a pair of rachet wheels contiguous therewith, the torque between the disc brake wheel and the rachet wheel (which ever wheel is being racheted by the load bearing disc) is proportional to the load on the screw shaft (and hence the actuator for the flight control surface). A Hall-effect device is mounted above the pawls associated with the rachet wheels for measuring the movement of the pawls in a closed loop circuit for the purpose of determining not only a faultlessly running braking condition but also to indicate whether a faulty condition exists, as well as what kind of fault is being detected.

Abstract: A device for measuring the tensile force on a thread includes a housing having thread guides at the points of inlet and outlet of the thread. A spring plate is mounted on the housing intermediate the thread guides and has a dumbbell-shaped guide member at its end for engaging the thread. The spring plate is so mounted that the tension on the thread displaces the spring plate from its initial unflexed position. Adjacent the guide member on the movable spring plate is a permanent magnet which moves with the spring plate as it displaces. A sensor employing the Hall effect is fixed to the housing at a given distance from the magnet. Movements by the magnet are detected by the Hall sensor, which produces an output signal indicative of the displacement of the spring plate, which signal is processed to give an indication of the thread tension.

Abstract: An activity sensor which provides an indication of motion caused by changes in acceleration of a person or animal, and wherein such changes of motion are sensed by a movable magnet which is biased to a rest position along a guide. The axis of the path of movement of the movable magnet is substantially parallel to the direction of accelerations of interest. A Hall effect sensor is provided for sensing motions of the movable magnet from its rest position, and it provides an output proportional to these movements.

Abstract: Parameter sensors and monitors are described incorporating one of a variety of parameter responsive structures constructed and arranged for expansion and contraction causing a component of motion and displacement along at least one direction in response to variations of a selected parameter. A reference mounting supports the parameter responsive structure and either a magnet element or Hall effect transducer is secured relative to the reference mounting or housing in alignment with a selected direction of a component of motion and displacement caused by expansion and contraction of the parameter responsive structure. The other of said magnet element and Hall effect transducer is mounted for relative displacement along said selected direction in response to expansion and contraction of the parameter responsive structure.

Abstract: There is described a system for monitoring the operation of output transducers of a central control and monitoring unit for machines usable in production and/or product packaging lines. The main characteristic of this system lies in the fact that it includes a detector for detecting the passage of current in the transducer without relying on a voltage drop detection system.

Abstract: A wind velocity sensor provided with a stationary base having a permanent magnet or a Hall element fixed thereon, an elastic plate having the other of the permanent magnet and the Hall element fixed to a portion opposite to the one of the permanent magnet and the Hall element, and an inversion amplifier having the outputs of the Hall element inputted thereto, the inversion amplifier developing a liner output with respect to wind velocity.

Abstract: A flow meter includes a piston having magnetic properties. The piston is located in a cylinder having an outlet slot. Fluid flow into the cylinder and out through the slot determines the position of the piston. The piston is preferably of a magnetic material which interacts with a Hall effect type transducer to produce an output voltage related to the position of the piston and, therefore, to the flow.

Abstract: An electric signal in an electrical level measuring transducer shall be generated in an explosion-proof manner, which continuously depends on the level in the interior of a container. The buoyancy of a float 14 is converted into a movement of a permanent magnet 36. The permanent magnet moves in the area of a Hall generator 44. The signal processing elements 48 are disposed in a tightly closed housing in explosion-proof manner. The Hall generator 44 is located in a non-magnetic part of the wall 38 of the housing 20.

Abstract: A large number of equally spaced Hall-sensors form a column. They are mounted in a tube with a closed bottom. Each sensor is a packaged integrated circuit with a Hall-cell connected to a Schmitt Trigger circuit. An annular float being fitted slidably about the tube carries a compound magnet that generates a pattern of regularly spaced apart magnetic field regions each having the same dimensions and each capable of switching an immediately adjacent Hall-sensor. The Hall-sensors are energized sequentially and one at one time. By counting the number of Hall-sensors scanned, from the beginning end of the column to the first Hall-sensor that is switched, a rough measure of the liquid level is obtained. The magnetic field regions are spaced apart by a distance that is not equal to the Hall-sensor spacing so that the pattern of Hall-sensor output voltages provides a unique vernier measure of the liquid level that is appropriately added to the afore-said rough measure.

Abstract: The present invention provides a device for generating an electrical output signal representative of the flow rate through a fluid flow meter of the type having a mechanical output member movable in an amount proportional to the fluid flow rate. The device comprises the U-shaped magnet having a north and south pole and a Hall effect transducer positioned between the poles of the magnet. The transducer produces an electrical signal representative of the distance between the transducer and one of the magnetic poles. The magnet in turn is connected to the mechanical output member from the flow meter so that the magnet moves in unison with the output member from the flow meter thus varying the transducer electrical output. The output from the transducer is electrically connected to a conventional electrical indicator to produce an indication of the fluid flow rate through the flow meter.

Abstract: An infrared tunnel oven includes one or more oven tiers each having a horizontal cooking tunnel with entrance and exit at opposite ends, the tier(s) being supported by a base. Each tunnel is divided along its length into multiple heating zones. The roof and hearth surfaces of each tunnel are heated by electrical heating panels for direct IR emission from the roof and hearth for direct absorption by food products conveyed through the tunnel by a continuous speed-controllable conveyor. Microprocessor-controlled circuitry monitors, by a thermocouple arrangement, the temperature of the roof and hearth in each zone, controlling the electric heating panels to maintain preselected roof and hearth temperatures in each such zone. The microprocessor also controls the conveyor speed for conveying of products along the length of the tunnel within a preselected cooking time. User selection of temperatures in the different zones and cooking time, as well as other functions, is provided by keypad entry.

Abstract: A device for the pick-up of measured values having a frame forming a first measurement reference and an element movable relatively to the frame and forming a second measurement reference. The device includes a carrier connected to the element forming the second measurement reference and a mechanical/electrical conversion system connected between the frame and the carrier. The conversion system produces a magnetic field directed at right angles to the direction of movement of the carrier and has at least one air gap within which the carrier is arranged to move at right angles to the magnetic field. Two pairs of field plates are arranged in the air gap and when the carrier is moved the extent of penetration of the pairs of the field plates by the magnetic field is changed. The device also includes a bridge circuit by which the field plates are connected. The bridge circuit includes in one diagonal thereof a device for the display of measured values and is connected across the other diagonal thereof to a d.c.

Abstract: The dynamometer has a fixed frame in which a Hall effect generator measures the flux density at a location indicative of the flux in the gap between the rotor and the inductor rings. The gap flux density is influenced by the flux induced by the field and the opposing emf generated in the rings as the rotor rotates. The Hall voltage H.sub.V is related to and substituted for the flux density B in the formula Torque ##EQU1## where r and s are constants proportional to eddy resistance and inductance and f is the frequency in cycles per second. The Hall voltage and a speed pulse signal are fed into computer means to provide a direct readout for torque, horsepower and speed.

Abstract: A fluid flow meter comprising a fluid tight housing including an inlet and an outlet; a hollow liner mounted within the housing including at least one slot, the slot for receiving fluid from the inlet and communicating it to the outlet; a magnetic piston slidably positioned within the liner for movement in response to the flow of fluid from the inlet through the slot; and a Hall effect transducer mounted in the housing in substantially side-by-side relation to the piston for producing an electrical signal corresponding to the position of the piston in the cylinder.

Abstract: A force measuring procedure and a force measuring apparatus are used to control the power hoist of an agricultural tractor. The force measuring procedure operates in such a manner that the relative displacement of a point on an elastic system is detected by at least one Hall sensor disposed on either the elastic system or on the fixed frame with the Hall sensor being located in a magnetic field with a predeterminable magnetic flux. For this the force measuring apparatus has a flex rod attached to at least one of a pair of lower hitches which indicates the bending moment, and the Hall sensor is mounted with its detector surface essentially in the primary plane of bending deformation of the flex rod and is connected to the control circuit of the power hoist.

Abstract: A deformable pressure chamber (10) moves a permanent magnet (12) carried by it as it is deformed. A GaAs Hall element (13) is disposed on a substrate plate (1) opposite the permanent magnet, and the substrate plate also carries a hybrid circuit including a temperature compensating network of thick film resistors and an amplifier. The Hall element is subject to only small temperature effects, and these are compensated in a circuit that can work with a low supply voltage.

Abstract: A control device and method of making the same are provided, the control device having a housing provided with an actuator chamber separated from a pressure differential chamber by a wall having an opening therethrough receiving an axially movable actuator pin that transmits axial movement of a movable part in the pressure differential chamber to the actuator chamber. A Hall effect transducer is disposed in the actuator chamber and the actuator pin has a magnet unit for operating the transducer as the movable part axially moves the actuator pin relative to the housing, the magnet unit being disposed in offset relation to the axis of the actuator pin and moving in unison therewith relative to the transducer.

Abstract: A large number of equally spaced Hall-sensors form a column. They are mounted in a tube with a closed bottom. Each sensor is a packaged integrated circuit with a Hall-cell connected to a Schmitt Trigger circuit. An annular float being fitted slidably about the tube carries a compound magnet that generates a pattern of spaced apart magnetic field regions each capable of switching an immediately adjacent Hall-sensor. The Hall sensors are energized sequentially and one at one time. By counting the number of Hall-sensors scanned, from the beginning end of the column to the first Hall-sensor that is switched, a rough measure of the liquid level is obtained. The magnetic field regions are spaced apart by a distance that is not equal to the Hall-sensor spacing so that the pattern of Hall sensor output voltages provides a unique vernier measure of the liquid level that is appropriately added to the aforesaid rough measure.

Abstract: A poppet fuel injector valve includes a poppet valve which is positioned within a chamber in the injector and displaceable between open and closed positions. A passageway extends from an exterior surface of the injector into close proximity to the cavity in which the poppet valve is located. A valve position sensor is dimensioned to fit within the passageway and is displaceable into close proximity to the poppet valve. The valve position sensor generates an electrical output signal which corresponds to mechanical displacements of the poppet valve.

Abstract: Matching components of a magnetic locking assembly are magnetically attracted into mating relationship until a predetermined magnetic flux is established in one of the components. Such established predetermined flux is monitored to detect locking power diminutions between the locking assembly components. External magnetic fields applied to the locking assembly in an attempt to counterfeit the mentioned predetermined magnetic flux may be detected and indicated for security reasons.

Abstract: Apparatus for testing permanent magnets such as in a generator or alternator embodied in a fly wheel. The apparatus includes a testing head on which the fly wheel is placed for the purpose. The fly wheel has a circular series of permanent magnets, and the head has a corresponding circular series of electro magnets, with Hall Generators between the electro-magnets, the Hall Generators having an element (bismuth) the resistence of which is affected by a magnetic field. The apparatus includes an electrical circuit embodying the Hall Generators, and the electro-magnets are charged, and the voltage set up through the Hall Generators indicates the voltage condition of the permanent magnets and is the voltage which is tested by the apparatus. The apparatus can also be used for motors as well as generators and alternators.

Abstract: A device capable of sensing forces exerted by fluids, particularly liquids, and thus may be used to sense fluid level and fluid flow. Preferred embodiments of the device include a switch means capable of being actuated without the exertion of substantial mechanical force thereon and an elongated body of low mass mounted for pivotal movement about an end thereof with switch actuation means at an end thereof in operative relation to the switch means only when the axis of elongation of the body is aligned with the switch means. Features of the device provide reduced inertial effects and reduced gravitational force requirements, as well as reduced wear, in operation.

Abstract: A magnetic field is determined with a Hall element having a high sensitivity. Such an element is very susceptible to a variation of environmental temperature and thus requires a compensation thereof for the determination of a magnetic field. Two electric signals, indicative of the magnitudes of the Hall voltage and the temperature, respectively, are produced and fed into respective inputs of an analog calculator to thereby indicate the determined magnitude of the magnetic field automatically. In one aspect of the invention, the temperature signal may be obtained by detecting a control voltage across the control current terminals of the Hall element during passage of the control current therethrough. Alternatively, it may be obtained by means of a thermistor.

Abstract: A printing device is provided which includes a feeler pivotally mounted on a printer frame and urged into engagement with record media positioned on a platen for printing. A magnetic element on the feeler coacts with a Hall generator on the frame to provide a control voltage which is effective to control a motor for positioning of the frame so that a print head mounted on said frame is located at a proper distance from the record media for printing thereon.

Abstract: A method and apparatus for providing data related to the ice breaking efficiency of a hull of a vessel as the vessel passes through ice, and particularly for providing data related to the frictional forces experienced on the hull of the vessel as the vessel passes through ice. Movable means is carried on the hull of the vessel generally flush with the hull for displacement in response to forces applied thereto as the vessel passes through ice. The displacement of said movable means relative to the hull of the vessel is determined as a manifestation of frictional forces between the hull of the vessel and the ice. The movable means preferably comprises a generally coplanar relation therewith and flush with the outer hull skin. The plate is mounted on a plate suspending means which permits omnidirectional movement of the plate at least in the plane of the hull.

Abstract: A fluid flow system including automatic feeder control for supplying chemicals to fluid flowing through a conduit and utilizing a Hall Effect detector which supplies an output to a digital counter which feeds a comparator that operates a timer and electronic switch to control the chemical feeder.