Abstract: Piezomagnetic, magneto-strictive, or electro-strictive material particles may also be distributed throughout the structural material of the structural member, which serve to amplify and otherwise enhance the signals from the piezoelectric material particles. The piezoelectric, electro-strictive, magneto-strictive, and/or piezomagnetic material particles may allow the structural member to exhibit an electrical and/or magnetic response to forces on the structural member, such as accelerations. This may allow the structural member to function as a force sensor or an accelerometer. Signals induced by such external forces or accelerations may be taken from the conductive pickups and used for various operations, for example, for arming a warhead of a missile or for triggering passenger safety features such as air bags in automobiles.

Abstract: A rotation angle detector includes a rotator, first and second detecting bodies, an auxiliary detecting body, first and second detectors, an auxiliary detector, and a controller. The first detecting body rotates in association with the rotator, and the first detector detects rotation of the first detecting body. The second detecting body rotates in association with the first detecting body at a different speed therefrom, and the second detector detects rotation of the second detecting body. The auxiliary detecting body is engaged with the rotator at a position symmetrical to the first detecting body with respect to a rotation axis of the rotator. The auxiliary detector detects rotation of the auxiliary detecting body. The controller detects a rotation angle of the rotator based on detection signals from the first, second, and auxiliary detectors.

Abstract: A shaft assembly, includes an elongated shaft and a flywheel mounted to an end of the shaft. An encoder is mounted to the shaft and includes an annular support ring having a radially inwardly extending portion and an axially extending portion extending from a radially outer end of the radially inwardly extending portion. The radially inwardly extending portion defines a spring section which is compressed between the flywheel and the end of the shaft, and an encoder material is disposed on the axially extending portion of the annular support ring.

Abstract: Angular position detection sensors include a capacitive sensor embodiment and an inductive sensor embodiment. A non-rotating excitation element is electromagnetically coupled to a non-rotating receiver element. The electromagnetic coupling is varied by an electrically passive, rotating element disposed between the non-rotating excitation element and the non-rotating receiver element. Excitation signals applied to the non-rotating excitation element are electromagnetically coupled to the non-rotating receiver element, producing a single output signal directly indicative of the angular position of the rotating element.

Abstract: An encoder 12 changing a characteristic thereof alternately and at equal intervals with respect to circumferential direction is supported by and fixed to the hub 4 concentrically. A detecting portion of a sensor 13 supported by the outer ring 3 is closely opposed to a detected face of the encoder 12. Width dimensions of first, second detecting portions provided at the detected face are changed continuously with respect to direction of operating a load to be detected. In accordance with a change of the load, a pattern of changing an output signal of the sensor 13 is changed. Thus, the load is calculated by observing the pattern. By performing filtering process on a signal expressing the change in the pattern, a variation based on the mounting error or the like is removed.

Abstract: A rotation sensor for outputting a pulse signal, which has a frequency corresponding to a rotation speed of a rotor, to a wire. The rotation sensor includes a modulation unit and an output unit. The modulation unit modulates an information signal representing information other than the rotation speed into a carrier wave having a frequency higher than the frequency of the pulse signal. The output unit superimposes and outputs to the wire the pulse signal and the carrier wave. Accordingly, the rotation sensor performs stable information transmission that is not dependent on the rotation speed of the rotor.

Abstract: The invention concerns a device for measuring the speed and direction of rotation of an object (3) near to which it is placed. It comprises: a magnetic detection device (2) that delivers, in response to a rotation of the object (3) generating a magnetic field variation, signals representative of its speed and its direction of rotation, a conductor (4) intended to be connected to a power source to supply current to the magnetic detection device (2) at least, current receptor means (6) placed between the magnetic detection device (2) and the conductor (4) that create, from signals coming from said magnetic detection device (2), a modulation of the current (Iout) flowing in the conductor (4), said modulated current (Iout) reflecting both the speed and the direction of rotation of the object (3). Application particularly in the oil industry.

Abstract: Sensor head or detector head (1) composed primarily of a protective casing that forms a hollow body (2) with an external surface, the so-called active surface (2?), and of a sensing or detection element mounted in the hollow body and adjacent to part of the front wall of the protective casing defining the active surface, at the level of the internal surface opposite the latter, the sensor head characterized in that the sensing element (3) is located at a distance from the internal surface (4?) of the part of the wall (4) of the hollow body (2) in such a way as to delineate an interstitial space (5) of small thickness (d) forming a mechanical and physical decoupling interface between the part of the wall (4) and the sensing element (3).

Abstract: A method and system for calculation of rotation dependent parameters in a system that senses shaft rotation of a toothed speed wheel. The method includes determining the passing edges of multiple gear teeth on a rotating speed wheel; calculating rotational speed of the rotating machine based on the passing edges of multiple gear teeth of the speed wheel; calculating a rotation independent tooth spacing correction factor for each gear tooth on the rotating wheel; and correcting the calculated rotational speed of the rotating machine using the tooth corrections.

Abstract: A rotation detecting sensor includes a magnetic element group include at least three magnetic elements each of which detects rotations of a rotary body that includes a magnetic body, output portions each for outputting a signal generated at each of the magnetic elements to an outside, and element selecting means for selecting arbitrary two magnetic elements from the magnetic element group and applying the generated signal to the two output portions.

Abstract: An accelerometer system includes a capacitor plate fixed within a housing and a flexure plate positioned substantially parallel to the capacitor plate a distance therefrom. The distance varies in response to acceleration forces acting upon the flexure plate such that the flexure plate and the capacitor plate generate a capacitance signal. A magnet is coupled to the flexure plate and generates a magnetic field, which moves as the flexure plate flexes. A coil winding around the flexure plate generates a second magnetic field as a function of capacitance signal, thus opposing the flexure plate magnetic field, and thereby returning the flexure plate to a null position.

Abstract: A rotation angle detecting device is rotated by a rotating object via a gear mechanism to detect a rotation angle of the rotating object. The rotation angle detecting device includes a housing, a magnet rotor unit having a permanent magnet and a central hole, a magnetic sensor unit including a pair of magnetic sensor elements each of which detects magnetic flux density of a magnetic field generated by the permanent magnet in a direction different from the other, and a signal processor that calculates a rotation angle of the rotating object from the magnetic flux density. The magnetic rotor unit includes a mechanism for changing the magnetic flux density as the number of turns of the magnet rotor unit changes.

Abstract: A system for decoding a signal of a rotating portion of a machine. The system includes a sensor configured to output N signals based on signals received from the rotating portion, and a processor configured to derive a value from a plurality of differences between sampled data obtained from the N signals.

Abstract: An actuator having an output shaft, a motor for rotating the output shaft between a first position and a second position, and an electronic control module having a controller and a sensor. The sensor is configured to output a signal to the controller indicative of the position of the output shaft, and the controller is configured to determine whether the output shaft is in the first position or the second position.

Abstract: A method for assembling a speed-sensing device for monitoring an angular velocity of a rotatable shaft, comprises the steps of: providing a hollow housing having a speed sensor hole, installing a stopper plug into the speed sensor hole so that a stein portion of the stopper plugs extends into the housing, inserting a tone wheel into the housing and inserting the shaft into the housing until the shaft positively engages the tone wheel. The speed-sensing device comprises the tone wheel non-rotatably mounted to the shaft. The shaft has a shaft groove formed on an outer peripheral surface thereof, while the tone wheel has a wheel groove formed on an inner peripheral surface thereof. The speed-sensing device further includes a snap ring retainer provided to engage the complementary shaft and wheel grooves in order to prevent movement of the tone wheel along the shaft.

Abstract: Rotation detecting apparatus for detecting rotation of a magnetic rotor includes: a sensor chip having a magnetoresistive device; and a bias magnet. The magnetoresistive device is capable of detecting change of a magnetic vector near the sensor chip so that the rotation detecting apparatus detects the rotation of the magnetic rotor. The change of the magnetic vector is generated by the bias magnetic field and the rotation of the magnetic rotor. The bias magnet is disposed around the sensor chip so that a deflection angle of the magnetic vector is controllable.

Abstract: A speedometer gear output structure includes a gearbox installed in a motorcycle and holding a driven gear and an output gear for synchronous rotation with the wheels of the motorcycle, an annular magnetic device fastened to the gear shaft of the output gear for synchronous rotation, and a circuit board mounted in the gearbox and holding a sensor corresponding to peripheral magnetic zones of the annular magnetic device for outputting an output signal indicative of the speed of rotation of the output gear.

Abstract: A measurement apparatus includes a speed sensor, a cadence sensor and a display portion. The apparatus further includes a transmit portion for wirelessly transmitting signals detected by the speed sensor and the cadence sensor to the display portion. The transmit portion is provided with a shaft portion extending in one direction, which rotatably supports the cadence sensor and the speed sensor. A measurement body portion including the speed sensor, the cadence sensor and the transmit portion is mounted on chain stay. The display portion is mounted on a portion of a handle in the field of vision of a rider of the bicycle, and it has functions of receiving and processing signals transmitted from the transmit portion, and displaying prescribed information. Thus, the measurement apparatus that can easily be mounted to a bicycle and the sensor apparatus applied thereto are obtained.

Abstract: An apparatus for detecting rotation of a bicycle part comprises a casing member comprising a generally annular body structured to be mounted to the bicycle part so that the annular body is incapable of rotating relative to the bicycle part as the bicycle part rotates in opposite directions around a rotational axis. The annular body includes a plurality of circumferentially disposed exposed magnet mounting portions that are concentric with respect to the rotational axis, and a cover member is detachably mounted to the annular body for blocking the plurality of magnet mounting portions.

Abstract: A highly simply technical transmitter system for a Ferraris movement transmitter, wherein several magnetic field generators (M1,M2,M3) form at least one magnetic circuit with a moveable, non-magnetic electrically conducting rotating measuring body and speed-dependent or acceleration-dependent output signals can be generated by means of magnetic field sensors coupled thereto, embodied in such a way that a preferably cylindrical device shaft (W1,W2,W3) is provided as a measuring body.

Abstract: A detector of a rotation angle and torque is disclosed. First gear (1) and second gear (2) are coupled to input shaft (4) and output shaft (6) of a torsion-bar unit respectively. First magnet (20a) magnetized in a radius direction is rigidly mounted to first rotor (10) engaging with first gear (1). Second magnet (20b) magnetized in a radius direction is rigidly mounted to second rotor (16) engaging with second gear (3). Circuit board (15) is placed between first rotor (10) and second rotor (16). Circuit board (15) includes first magnetism detecting element (21a) on its first face confronting the first magnet (20a), and also includes second magnetism detecting element (21b) on its second face confronting the second magnet (20b).

Abstract: A device for measuring a motion of a moving electrically conducting body is disclosed. A magnetic field generated by, for example, electromagnets or permanent magnets, penetrates at least a partial area of the moving body. Two or more measuring devices are arranged outside the magnetic field to measure a measurement magnetic field that is induced by electrical currents in the moving body. The measuring devices are arranged essentially symmetrically with respect to the magnetic field generating means or the moving body. The measurement magnetic field represents at least one motion variable of the moving body. The measuring device is thereby no longer subjected to the temperature-dependent variations of the exciting field.

Abstract: In order to compensate for a drop in sensitivity at high rotational speeds, an acceleration sensor having an inductive measuring head (T) which cooperates with a moving Ferraris disk (F) essentially over a main magnetic field and which supplies an acceleration-dependent variable (Vdet; V?) is expanded by an additional DC magnetic field excitation circuit (13, 14, IK, RK) with a means for driving the latter with the effect that the additional DC magnetic field acts in a compensating fashion on an eddy-current DC field, starting from a relatively high rotational speed (?) of the Ferraris disk (F). This can be performed by amplifying the main magnetic field or by reducing the eddy-current DC field. A control signal (V?), dependent on rotational speed, which both can be generated outside the sensor via a characteristic curve, and can be derived in the form of a control loop from the sensor signal (V?), serves as a drive.

Abstract: A detector for monitoring rotation of a target includes a sensor unit, a microcontroller, and an operator conversation apparatus. The operator conversation apparatus is connected to the microcontroller and enables setting of the detector in a working mode or a learning mode.

Abstract: In a method for detecting rotational speed of an internal combustion engine (1), a sector wheel (4) which is driven by the internal combustion engine (1) is scanned, the run of a specific segment of the sector wheel is detected, the duration of said segment-run is measured and a rotational speed value is determined therefrom, the duration of the run of a specific segment is re-measured, a relative variation between two consecutive segment-runs is determined and the rotational speed value is determined therefrom.

Abstract: A wheel speed sensor has a detection element having at least one lead for detecting a wheel speed, at least one terminal portion connected to the lead of the detection element, a holder portion having a detection element fitting portion fitting the detection element therein and a terminal portion fitting portion fitting the terminal portion therein, and a resin sealed portion sealing the holder portion in a state the detection element and the terminal portion connected with an electric wire are held in the holder portion. The detection element fitting portion and the terminal portion fitting portion are disposed such that the lead of the detection element is brought into abutment with or proximity to a predetermined location of the terminal portion when the detection element and the terminal-portion are fitted in the detection element fitting portion and the terminal portion fitting portion, respectively.

Abstract: A measurement system for determining acceleration and a position of an object. The measurement system includes a first sensor system for determining an acceleration of an object, the first sensor having a body with an electrically conducting measuring structure, a device for generating a first magnetic field, which acts on the measuring structure and a detector for detecting a second magnetic field or field changes, which are created by eddy currents generated by the measuring structure, the detector generating an output signal. A second sensor system for determining a position of the object, the second sensor system includes a scale graduation that lies opposite the detector and is scanned by the detector in a scanning area in which the measuring structure and the scale graduation are arranged placed on top of each other, or integrated into each other, and wherein the detector generates an acceleration signal and a position signal from a common scanning area.

Abstract: To provide a wheel support bearing assembly having a capability of detecting the number of revolutions of a wheel, having no risk of breaking of wire outside a vehicle body, capable of reducing the weight and cost of an automotive vehicle. This wheel support bearing assembly for rotatably supporting a wheel 13 relative to a vehicle body structure 12 includes an outer member 1 having its inner periphery formed with plural rows of raceways 6 and 7, an inner member 2 having raceways 8 and 9 confronting respectively to the raceways 6 and 7, and rows of rolling elements 3 accommodated respectively between the raceways. An electric generator 4 for generating an electric power as one of the outer and inner members 1 and 2 rotates relative to the other of the outer and inner members 1 and 2. A signal indicative of the number of revolutions of the wheel 13 outputted from the electric generator 4 is transmitted wireless by mean of a wireless transmitting means 5A.

Abstract: A bearing assembly tachometer device for attachment to a rotating shaft which comprises bearing target members disposed between a rotating inner ring member and a non-rotating outer ring to reduce friction therebetween, and a sensing device such as a Hall Effect sensor for detecting passage of the bearing target members as the inner ring member rotates, where the bearing target members are fixed in equidistant circumferential position about the inner ring member such that each said bearing target member rotates about the central axis of the inner ring member the same number of rotations as the inner ring member itself.

Abstract: Abnormal rotational speed detection means of the variable speed fan motor according to the invention comprises a threshold width setting means that generates a threshold width set value of the rotational speed and a subtractor means that subtracts the threshold width set value from a rotational speed command value transmitted from a rotational speed command means. A value obtained by subtracting the threshold width set value from the rotational speed command value is put into a rotational speed comparator means as the threshold value for the rotational speed of the fan motor.

Abstract: In a method and device for measuring at least one parameter of a metal bed, measuring is obtained by a magnetic field being generated from one side of the metal bed so that eddy currents are generated in the metal bed as the metal bed moves relative to the magnetic field. The metal bed and the magnetic field are made to move relative to one another. A force related to the eddy currents affects a body and the action of the force on the body is detected by a detecting device, the detected force being a function of a desired parameter of the metal bed.

Abstract: A control valve assembly for the rotary or linear actuation of control valves using contactless technology and the use of direct integration of electronic componentry into a lead frame interconnection assembly includes a contactless motor, a control valve in mechanical communication with the contactless motor through a gear system, and a lead frame interconnection assembly having electronic componentry relevant to the contactless motor and the control valve integrally formed therein. The contactless motor includes a commutator magnet disposed on a rotor shaft thereof. The commutator magnet is in magnetic communication with at least two commutator chips integrally formed with the lead frame interconnection assembly. The control valve includes a throttle element disposed in a throttle bore, an output shaft depending from the throttle element, and at least one position sensing magnet disposed on an end of the output shaft distal from the throttle element.

Abstract: A water bike equipped with a speed meter wherein a speed meter sensor 1 including a coil for generating a magnetic flux and electrodes disposed at positions vertical to both flowing direction of a fluid and direction of the magnetic flux, and for measuring the speed of the water bike on water by the value of electromotive force generated by an electromagnetic induction operation, is fitted to a submerged portion of the water bike 2.

Abstract: The present invention relates to a linear distance sensor for motor vehicles which comprises a displaceable element (4, 5, 7) and a stator (1, 2, 3). The displaceable element includes a magnetic encoder. Sensor modules that operate according to the AMR principle, GMR principle, or Hall principle are linked stationarily to the stator. The displaceable element is guided by way of a bearing (11) that is connected to the stator and embraces and axially guides the displaceable element. The sensor module(s) is/are linked stationarily to the stator. The field-generating means is/are positively connected to the displaceable element along the longitudinal axis of the displaceable element.

Abstract: A GMI sensor comprised of a GMI fiber for determining a spin rate of a rotating body in which the GMI fiber is fixed relative to the body as the body spins within an external magnetic field is presented. The sensor comprises a GMI fiber having multiple axes of sensitivity with at least two of the axes being oriented one to the other such that the segments act independently, but employing a single conditioning circuit.

Abstract: An eddy current sensor including an arrangement for generating a first magenetic flux, which is essentially directed vertically with respect to a moved body, a detector coil for detecting an eddy field in the moved body and a second arrangement which generates a further adjustable magnetic flux, which is superimposed on the first magnetic flux to form a resultant magnetic flux.

Abstract: In order to compensate for a drop in sensitivity at high rotational speeds, an acceleration sensor having an inductive measuring head (T) which cooperates with a moving Ferraris disk (F) essentially over a main magnetic field and which supplies an acceleration-dependent variable (Vdet; V&agr;) is expanded by an additional DC magnetic field excitation circuit (13, 14, IK, RK) with a means for driving the latter with the effect that the additional DC magnetic field acts in a compensating fashion on an eddy-current DC field, starting from a relatively high rotational speed (&ohgr;) of the Ferraris disk (F). This can be performed by amplifying the main magnetic field or by reducing the eddy-current DC field. A control signal (V&ohgr;), dependent on rotational speed, which both can be generated outside the sensor via a characteristic curve, and can be derived in the form of a control loop from the sensor signal (V&agr;), serves as a drive.

Abstract: A first portion of a perimeter of an outer circumferential portion of a tire is magnetized with a first polarity along the steel belt in one circumferential direction less than 360° and a second portion of the perimeter is magnetized with a second polarity in an opposite circumferential direction. The magnetic field generated by the magnetized steel belt is detected by two magnetic detection elements, which are set so that the magnetic field detection directions of the two magnetic detection elements are parallel to the side surface of the tire, and the two elements are juxtaposed in a direction perpendicular to the side surface of the tire.

Abstract: A pneumatic tire is provided that has a way to provide information. The pneumatic tire has at least at one predetermined location a rubber mixture that is permeated with magnetizable particles that are magnetized in a number of first zones and differently or not at all in a number of second zones. The tire can be used in a slip regulation system, and apparatus for producing such a tire are also provided.

Abstract: A device for sensing velocity variations in a conductive body 10 moving through a magnetic gap 12 between two discrete portions 13, 14 of a magnetic circuit 15. The magnetic circuit 15 generates a magnetic flux 16 in the gap 12 to induce eddy currents 17 in the body 10 moving through the gap. The device includes an eddy current sensor defining at least one further gap 24 through which the body 10 is also moved, and at least one sensor coil 18. A voltage is induced in the coil by variations in the induced eddy currents. The voltage is detectable; providing an indication of variations, that is to say accelerations or decelerations, in velocity by providing two discrete magnetic circuit portions, the size and weight of the device be reduced while enhancing the ability to sense eddy currents. The device may be used in a vehicle to sense vibration, acceleration, or other motion.

Abstract: A method and apparatus is disclosed for monitoring an angular displacement, such as angle position and the direction of displacement. The method and apparatus includes at least one resonator placed in proximity to a electrodynamic profile and exciting within said resonator an alternating electromagnetic field. The electromagnetic field should be at a frequency at which the electromagnetic field contacts the electrodynamic profile and then variations of the electromagnetic field parameters are measured for the resonator caused by rotating the electrodynamic profile. Excitation of the resonator is by an electromagnetic field in the form of at least one slowed electromagnetic wave having a suitable energy distribution of the electric and magnetic fields for measuring the electromagnetic field parameters.

Abstract: An arrangement for detecting the turbocharger rotational speed on internal-combustion engines is provided with at least one piezoelectric acceleration sensor fixed on the turbocharger and with an analyzing circuit having an analog filter arrangement for filtering the output signals of the acceleration sensor. The output signals of the filter arrangement are fed by way of a frequency-to-voltage converter in the form of an analog voltage, or directly in the form of frequency signals, as input signals to an electronic control unit of the internal-combustion engine or to a measuring and/or display unit. As a result, the turbocharger rotational speed can be detected at a reasonable cost with a small and robust arrangement suitable for mass production and requiring no constructional changes on the turbocharger.

Abstract: A rotary accelerometer having a nonrotatable cylindrical magnet return path formed out of magnetic permeable material. One or more permanent magnets, with two opposite poles, are disposed around the magnetic return path. An electrically conductive cup with an access for rotation therearound in which the cup surrounds the permanent magnets and the permanent magnets are arranged so as to produce a magnetic field through the cup into the nonrotatable cylindrical magnet return path, thereby inducing eddy currents inside the cup when rotating in the magnetic field. A stator core is formed out of magnetic permeable material surrounding the cup and nonrotatable relative thereto, the stator core having at least two pickup members. The stator is formed from at least one continuous piece of magnetic permeable material. One or more stator windings are disposed on to the pickup members of the stator core for sensing changes in a secondary magnetic field generated by the eddy currents in the cup.

Abstract: A speed sensor assembly is provided that isolates the internal components of the speed sensor from detrimental external environmental influences. Further provided is a new seal that seals between a housing and an overmold of a speed sensor and is capable of use in speed sensors of varying types and of all different sizes and shapes. Provided is a seal in which a bead of glue cured by ultraviolet light is applied around part of the exterior surface of a housing, after which an injected molded plastic overmold is applied over at least that part of the housing having the applied ultraviolet cured glue. In this way, once the housing is overmolded, the ultraviolet cured glue forms a gasket-like seal between the housing and the overmold preventing the penetration of water or other contaminants into the internals of the speed sensor. Also provided is a mounting fixture for use during a process of applying the seal to the housing.

Abstract: A device for sensing velocity variations in a conductive body 10 moving through a magnetic gap 12 between two discrete portions 13, 14 of a magnetic circuit 15, the magnetic circuit 15 generating a magnetic flux 16 in the gap 12 to induce eddy currents 17 in the body 10 moving therethrough, the device comprising eddy current sensor means 20 defining at least one further gap 24 through which the body 10 is also moved, and at least one sensor coil 18 having a voltage induced therein by variations in the induced eddy currents, said voltage being detectable to provide an indication of variations, that is to say accelerations or decelerations, in the velocity of the moving body 10.

Abstract: A tire (12) used includes a steel belt in its outer circumferential portion. A magnetic sensor (14) including a pair of magnetic detection elements (18A, 18B), which are arranged so that their magnetic detection directions become parallel to each other or series each other, is set in the vicinity of a rear tire (12) in a trunk room of a vehicle (10). Changes in magnetic field upon revolution of the tire (12) are differentially detected by the magnetic detection elements (18A, 18B), and the revolution of the tire (12) is detected on the basis of the differentially detected output waveform. Among a plurality of peaks present in the differentially detected output waveform, a peak, the potential difference from the immediately preceding peak of which is equal to or larger than a predetermined threshold value, is detected as an effective peak, which is effective for tire revolution detection, and the revolution speed of the tire is calculated by detecting the number of effective peaks.

Abstract: A speed sensor (10) includes a sensor housing (12) mounted to the wall of a transmission, and a pole piece (34) extends out of the sensor housing (12) into the transmission fluid. The pole piece (34) is held by a plastic spool (26) within the sensor housing (12), and an electric coil (28) surrounds the spool (26) and is magnetically coupled to the pole piece (34). The spool (26) is formed with a rib ring (41) that extends away from the pole piece (34) and that terminates in an outer periphery that is closely spaced from the inside wall of the sensor housing (12). To block metal particles in the fluid from entering between the spool (26) and sensor housing (12) that would otherwise damage the coil (28), two ribs (60) are formed on the outer periphery of the spool (26), and an interference fit is established between the ribs (60) and the sensor housing (12) such that the ribs (60) are deformed and the contaminants thereby blocked.