Abstract: In a method for monitoring mechanical wear caused by a first component on a second component, wherein the first and second components are movable relative to one another and wherein the first and second component are at least at times in mechanical contact with one another, at least one sensor head is arranged in a wear area to be monitored of the second component. The at least one sensor head is mechanically worn by the first component upon reaching a predetermined wear limit. When the at least one sensor head is mechanically worn, a measuring signal is generated by the at least one sensor head or a change of a measuring signal, produced by the at least one sensor head prior to having been mechanically worn, is detected.

Abstract: Wear of a rubbing member of a triction couple, such as an iron brake disc (15), which is subject to slow wear by frictional engagement by brake pads (17), is determined by attaching a carrier member (25) of wear determining arrangement (24) to the rubbing surface of the disc by electromagnet (28) and causing a transducer (33), such as magnetic displacement sensor having probe (33/2), to s an across the surface along a track (48). After an initial scan to map the surface the carrier is removed and re-attached after a period of brake usage, whereupon the surface is scanned again and wear assessed. The carrier is provided with feet (26/1) and biassed by a resilient electromagnet mount against the surface.

Abstract: It is an object of the invention to provide a method and apparatus for detecting the abrasion of an electrode of a stationary type welding gun which can accurately detect the amount of the abrasion of the electrode of the stationary type welding gun by means of a robot.

Abstract: Wear of a rubbing member of a triction couple, such as an iron brake disc (15), which is subject to slow wear by frictional engagement by brake pads (17), is determined by attaching a carrier member (25) of wear determining arrangement (24) to the rubbing surface of the disc by electromagnet (28) and causing a transducer (33), such as magnetic displacement sensor having probe (33/2), to s an across the surface along a track (48). After an initial scan to map the surface the carrier is removed and re-attached after a period of brake usage, whereupon the surface is scanned again and wear assessed. The carrier is provided with feet (26/1) and biassed by a resilient electromagnet mount against the surface.

Abstract: A stationary arranged sensor (4) is provided in the region of one of the dead centers of the piston movement to monitor the position of the path of motion of a piston (1) relative to a cylinder (2) whereby the sensor (4) measures the lateral distance (a) to an indicator unit (6) arranged on the piston (1). The sensor (4) is arranged in a recessed position relative to the inner surface of the cylinder (2) and is sealed toward the cylinder chamber (9) by means of a cover (8), and the indicator unit (6) on the piston (1) is designed as an anomaly (10) that is non-sensitive to contaminating deposits in the area of the face (11) of the piston (1).

Abstract: A device for measuring a clearance between tips of blades of a ring of blades and an interior wall of a casing surrounding the ring of blades in a turbomachine includes a probe which is mounted radially on the casing. The probe has an end made of a material that can be abraded by the tips of blades as they rotate. The device also includes a printed circuit arranged in a mid-plane of the probe. The probe contains an axis of rotation of the ring of blades. Further, the printed circuit includes a number of adjacent U-shaped electrical circuits that have bases arranged in a probe end likely to be abraded by the tips of blades. The bases lie at different depths from a reference level defining the interior wall of casing. The printed circuit also includes a recognizer for determining which U-shaped electrical circuits have been broken by abrasion and which U-shaped electrical circuits are intact.

Abstract: Disclosed are a device and a corresponding method to test the fretting of a ball bearing under precisely controlled conditions. The device employs a first piezoelectric actuator to deliver a pre-determined force to the surface of a ball bearing or other object to be tested. The force is applied in a first axis of motion. A second piezoelectric actuator, coupled to a flexure hinge platform, translates the workpiece in a second axis of motion that is different (and preferably substantially orthogonal) to the first axis. The combination of the relative motion between the workpiece and the force exerted upon it produces predetermined dynamic patterns of the stress and strain on the surfaces of the workpiece being tested. Closed-loop control architecture, piezoelectric actuators, and force/displacement sensors included in the device provide highly accurate and rapid tests.

Abstract: The present invention relates to a device for measuring the amount of liquid that a packaging unit, or cleaning pad, designed to absorb and/or adsorb liquid that is being transported or was spilled or was released. The packaging unit or pad has at least one sealing multi-layer comprising a first water soluble film and an absorbent/adsorbent material. When the liquid contacts the water soluble film, the liquid passes through the water-soluble film. When the liquid contacts the absorbent/adsorbent material, the absorbent/adsorbent material immobilizes the liquid material. This immobilization prevents the liquid from escaping from the absorbent/adsorbent material. The pad/packaging unit is then measured by the instant device to determine the amount of liquid obtained.

Abstract: The invention proposes a sensor element (5) for detecting a physical measurement variable such as a pressure, a temperature, a capacitance, or a gap width between two bodies (10, 20) that move in relation to each other during operation and experience high tribological stress. In certain areas between the surfaces of the bodies (10, 20) that move in relation to each other, in a surface region of at least one of the bodies (10), a sensitive layer (13, 30), in particular a sensor segment (13), is provided, which is separated from the body (10) by an insulation layer (12).

Abstract: A vessel, as for a cyclone separator, includes a continuous electrical conductor embedded in the wall of the vessel for sensing when the lining has eroded.

Abstract: A device implements a method of determining a cut resistance of a sample. The device includes a blade wherein the blade and the sample are relatively movable and a first apparatus that transfers energy to at least one of the sample and the blade to cause relative movement thereof in a direction parallel to a surface of the sample such that the blade contacts and cuts the sample until the imparted energy is expended and relative movement is terminated. A second apparatus measures a parameter of the relative movement to obtain an indication of the cut resistance of the sample.

Abstract: A gravelometer (20) includes a base unit (30) comprising compressed air receiver tank (40) having wheels (42) and feet (44). Main frame (46) connects tank (40) to a media gun frame or mount (50) and includes a bore (52) for releasably receiving and supporting a media gun (54) having a mounting flange (70) so that media inlet (56) is upwardly oriented and gun barrel or media outlet (57) extends through gun mount (50). Media inlet (56) interconnects via elongated con-duit (58) to a media supply system (60) which includes media supply hopper (62) and vibratory feeder assembly (64). A control system (80) having operator control panel (82) controls operations. A modular target box or chamber (90) is aided in being releasably connected to base unit (30) by locator pins (102). Chamber (90) includes media inlet (92), media outlet (94), which connects to spent media reclaim chamber (100), and specimen window (96) having a target holding toggle clamp (98).

Abstract: Novel methods for measuring the soothing attributes of personal care compositions are disclosed. The methods disclosed are particularly suitable for measuring and comparing the soothing attributes of facial tissue to determine which facial tissue is most soothing to damaged skin. The methods include damaging the skin of a test subject to a predetermined amount, contacting a test facial tissue with the damaged skin, and rating the soothing attributes of the facial tissue. In a preferred embodiment, the amount of skin damage on the skin is determined by the test subject.

Abstract: A wear gauge for determining excessive wear of the notches and lugs of an aircraft fueling nozzle adapter to expeditiously sense wear which might result in leakage of fuel during an aircraft refueling operation.

Abstract: In a method for monitoring mechanical wear caused by a first component on a second component, wherein the first and second components are movable relative to one another and wherein the first and second component are at least at times in mechanical contact with one another, at least one sensor head is arranged in a wear area to be monitored of the second component. The at least one sensor head is mechanically worn by the first component upon reaching a predetermined wear limit. When the at least one sensor head is mechanically worn, a measuring signal is generated by the at least one sensor head or a change of a measuring signal, produced by the at least one sensor head prior to having been mechanically worn, is detected.

Abstract: A fray tester for evaluating fray resistance of surgical sutures is provided, which comprises a first and a second pulley rotatably adapted in a spaced relation to each other, a tensioning weight, and a reciprocity driver. A suture having a first end portion, a second end portion and an intermediate portion is mounted in the fray tester such that the first end portion is subject to the tensioning weight, the intermediate portion is mounted to the first and second pulleys and defines a wrapped portion, the second end portion being connected to the reciprocating driver to cause the suture to rub against itself at a wrapped portion. The reciprocating driver includes a rotating wheel connected to a motor for providing the reciprocating movement to the suture to be tested. The tester may further include a revolution counter for counting and displaying the number of reciprocating cycles at the time the suture breaks or seizes.

Abstract: A testing assembly calculates stress levels along a cross section of a pneumatic tire. The cross section of the pneumatic tire includes its tire beads, sidewalls, and tread. The testing assembly includes a base and a plurality of mounts slidably secured to the base. Mounts secure each of the tire beads. The testing assembly also includes a platform that extends parallel across the testing assembly. The platform moves with respect to the base to simulate a tire under load. The platform does this by deforming the cross section of the tire as if it were under a load on a road. The method for using the testing assembly includes taking measurements of the cross section of the tire in an un-deflected state and a deflected state. Calculations between the two states identifies areas in the tire that stresses are damaging.

Abstract: A device and method for the high throughput screening of the abrasion resistance of coatings. The device includes a plurality of transducers, each of the plurality of transducers having at least one external surface, and a plurality of coatings, each of the plurality of coatings deposited onto the external surface(s) of one of the plurality of transducers. The device also includes a plurality of oscillation sources, coupled to the plurality of transducers, for generating and applying an oscillation potential to each of the plurality of transducers. Further, the device includes a plurality of oscillation detectors, coupled to the plurality of transducers, for measuring the oscillation frequency and a variation in oscillation frequency associated with abrasion resistance in each of the plurality of transducers. The method includes exposing each of the plurality of coatings to an abrasive material, the abrasive material causing a change in mass and/or viscoelastic property in each of the plurality of coatings.

Abstract: A seal for preventing leakage of fluid from between a first member and a second member the second member is capable of moving toward and away from the first member, the seal is adapted for engaged contact with the first member and the second member so as to prevent leakage of fluid between the first member and the seal and between the second member and the seal, the seal being more easily deteriorated than the second member such that friction between the seal and the second member wears the seal faster than the second member, the seal being adapted to retain a fluid tight seal against the second member as long as the seal has not worn beyond a specified depth; and a conductor for placement about the second member, the conductor being attached to the seal at the specified depth so as to contact the second member when the seal has worn to the specified depth, such that the existence of electrical discontinuity between the conductor and the second member indicates that the seal requires replacement, the conducto

Abstract: The present invention relates to a method for detecting a slip (s) of a belt part of a belt transmission, especially of a CVT transmission, having a transmission rpm ratio (ji).

Abstract: The present invention provides a device for testing the abrasiveness of paper and other sheet materials. The device comprises a punching module, a feed module for moving the material, a holding module that holds the material while the punching module penetrated the material, and an instrument that records and analyzes the amount of force needed to punch through the material and then calculates the abrasive properties of the material. The punching module comprises a punching instrument for punching the material, a driving mechanism for operating the punching instrument, and a measurement system that measures the amount of the force required to punch the material. A method for using the device is also provided.

Abstract: A system in the form of a database allowing operators of aircraft or any other equipment where components are subject to wear to manage all the maintenance, analysis and provisioning aspects of such components e.g. brake and wheel components. The system is able to predict component, e.g. tyre, life to a high degree of accuracy based on the measured wear rate of the component or a related component such as each tyre's related brake unit.

Abstract: A method for selecting a cover material for use with a vehicle seat component includes establishing a material processability standard for cover materials selected from the group consisting of standards for marking resistance, fabric pattern, pile bind, rippling resistance, laminate wrinkle resistance, raveling resistance, seam puckering, stretch, and elongation; conducting testing of a cover material for compliance with the material processability standard to determine whether the cover material meets requirements of the material processability standard; and considering test results of the cover material before proceeding to utilize the cover material in manufacturing of the vehicle seat component.

Abstract: A fretting fixture accessory for a_test machine (10) that induces high-cycle fatigue (at kilohertz vibration rates) in a specimen of a material under test. The fretting fixture (20) is clamped to the test specimen (21), for the purpose of testing for fretting damage. The fixture (20) is designed to provide both the normal and shearing forces that result in fretting damage.

Abstract: A novel Stewart platform includes electromagnetic linear actuators. The motion platform may be included in an apparatus and method for testing footwear where a stationary shoe is struck by the motion platform.

Abstract: The present invention provides a reciprocating abrasion tester capable of conducting an abrasion test that exhibits small variations in evaluation even when conducted with respect to an automobile windshield glass using a wiper blade so as to conform to the actual abrasion conditions. This tester includes: a motor; reciprocating abrasion devices connected to the motor, and a loading member for applying load to the sliding member. Each of the reciprocating abrasion devices includes a crank, a reciprocating arm, and a sliding member for causing abrasion of a sample surface. Reciprocation cycles of the reciprocating abrasion devices differ from each other in phase.

Abstract: A blade tip clearance probe including a rub probe support removably attachable to a probe boss attachable to a fan case; a rub probe removably attachable to the rub probe support, the rub probe is composed of soft composite material, the rub probe support is able to receive the rub probe such that the rub probe can be adjusted to contact a blade tip; and an anti rotational lock being able to lock the rub probe into place in the rub probe support and being able to prevent rub prove movement. A method for measuring blade tip clearance including: fastening a rub probe support to a probe boss attached to a fan case; threading a rub probe into the rub probe support until the rub probe contacts a blade tip in the fan case; backing the rub probe off a specified turn angle; operating an engine attached to the blade tip; and measuring the probe wear.

Abstract: A metrology process, in accordance with the present invention, measures the dishing of a first feature made of a first material by determining the relative height of the first feature with respect to a second feature, where the first and second features have different dishing rates. The relative height of the first feature with respect to the second feature may be determined by measuring a first relative height of the first feature with respect to a reference location, measuring a second relative height of the second feature with respect to a reference location, and calculating the difference between the first and second relative heights. Alternatively, other methods may be used. The relative height is then correlated with calibration data to determine the amount of dishing of the first feature. The calibration data is generated by first providing a sample substrate with features approximately the same as the substrate to be measured, e.g.

Abstract: An apparatus is described which permits the lubricity of fuel compositions at or near temperatures and pressures experienced by compression ignition fuel injector components during operation in a running engine. The apparatus consists of means to apply a measured force between two surfaces and oscillate them at high frequency while wetted with a sample of the fuel composition heated to an operator selected temperature. Provision is made to permit operation at or near the flash point of the fuel compositions.

Abstract: This invention concerns a test apparatus and procedure used for quantitative and qualitative characterization of scratch and mar behavior of films or coatings, more particularly automotive coatings. The apparatus includes a micro-indentor that penetrates and scratches the coating to be characterized together with interrelated components for measuring the force applied, the length and depth of the indentor penetration, the geometry of the disturbed coating surface as well as a system for measuring, analyzing and comparing test results.

Abstract: A method and device for determining abrasive forces is disclosed. In order to determine the forces, at least two removable and distinguishable layers are applied on top of each other to a substrate or base so as to cover one another. Each layer requires a predetermined abrasive force for penetrating and removing the layer by scraping. The strength or force that is required is smaller the closer to the surface the layer is positioned. When the layers are subjected to abrasive forces, parts of the applied layers are scraped off, starting from the outermost layer and further downwards into the underlying layers. In this manner, one of the layers is exposed at each point, thereby indicating the abrasive force at that point. The exposed surface of each layer may then be identified. The method and device are particularly suitable in car-crash testing in order to assess the abrasive forces arising from airbags.

Abstract: A method of detecting premature wear of engine bearings in locomotive engine applications includes incorporating bismuth as a tracer element into the liner of bearing metal applied to a rigid metal backing of the bearing. A soft metal overlay free of bismuth is applied over the bearing liner and the bearing installed in the engine. The engine oil is periodically tested for the presence of bismuth. Early detection indicates premature wear of the overlay, enabling corrective action to be taken to protect the engine.

Abstract: The present invention provides a device for testing the abrasiveness of paper and other sheet materials. The device comprises a punching module, a feed module for moving the material, a holding module that holds the material while the punching module penetrated the material, and an instrument that records and analyzes the amount of force needed to punch through the material and then calculates the abrasive properties of the material. The punching module comprises a punching instrument for punching the material, a driving mechanism for operating the punching instrument, and a measurement system that measures the amount of the force required to punch the material. A method for using the device is also provided.

Abstract: A method and apparatus is proposed for judging the friction behavior between two counter-running partners, each of which has a contact surface, with the one contact surface moving along the other contact surface in the operating state. One of the contact surfaces is charged with ultrasonic signals (UI; UW), ultrasonic signals which are reflected by the contact surface are received as echo signals (ES), the echo signals (ES) are supplied to an evaluation unit as received signals, the Doppler shift of the received signals is determined by means of the evaluation unit, and the friction behavior between the counter-running partners is judged by means of the Doppler shift.

Abstract: An apparatus for measuring the moisture vapor transmission rate of a shoe comprising, on a supporting footing, a hollow body made of self-supporting material, which reproduces the shape of a foot and is designed to support the shoe to be tested. The body is provided with through holes which are distributed thereon and contains water. The apparatus also comprises a sock made of waterproof and vapor-permeable material, arranged so as to enclose the hollow body. There is also a presser by means of which the hollow body is made to perform a relative movement between a configuration in which it is spaced from and a configuration in which it is compressed against the sole of the shoe. Conditioning fixtures are also provided for heating the water in the hollow body to a preset and constant temperature, and a weighing device B for measuring the weight of the body, with all the items associated therewith, and the shoe to be tested.

Abstract: An apparatus for accurately testing durability of a switch for an automobile in the state that the switch mounted on the instrument panel of the automobile, the apparatus comprises a switch operating means that operates a switch fitted on the instrument panel of an automobile, a jig means for setting the switch operating means to the inside of the automobile, and a control means for controlling operation of the switch operating means.

Abstract: The present apparatus for testing rolling physical characteristics of materials, especially rolling contact fatigue resistance of materials, represents the most simple and universal solution, by which it is possible to test not only laboratory tested objects prepared in advance, but also various final products or parts thereof. Thanks to linearly oscillating movement of the testing ball 30 foreseen by the apparatus according to the invention, it is much easier to test the surface 20 of the tested object 2. While appropriate point contact between the testing ball 30 and appropriate surface 20 of the tested object 2 is ensured, the testing ball 30 is linearly oscillatory rolled here and there along the surface 30 of the tested object 2, which is thereby clamped in appropriate clamping unit 1. The loading unit of the present invention comprises a bearing surface 33 arranged opposite to the tested object 2 and is equipped with a groove 34 arranged in the direction of rolling of the testing ball 30.

Abstract: Apparatus for and a method of fabricating a Coriolis flowmeter made primarily of plastic. The Coriolis flowmeter of the invention makes extensive use of plastic and injection molding. All embodiments have a dynamically active structure including a balance bar and/or at least one flow tube that is formed of plastic by the use of injection molding. Other embodiments includes plastic flanges and/or a plastic case, and/or plastic brace bars, and/or plastic bobbins for pick offs and a drive, and/or plastic mounting surfaces on a balance bar or flow tube for mounting the plastic bobbins of the pick offs and a driver.

Abstract: The present invention provides methods and devices for measuring granule impact strength and granule attrition rates by vibrating a small container of granules at a well-controlled amplitude in order to inflict reproducible damage to the granules. Damage to the granules is measured as a function of time and amplitude and attrition rates are measured in terms of dust generate per number of collisions versus mass of the granules. The measurements obtained yield a highly reproducible means for characterizing granule attrition, attrition rates, and fragmentation.

Abstract: A method and apparatus for measuring rub-off from an image-bearing substrate.

Abstract: A window seal testing machine for seals of the type used in powered automotive windows, the testing machine comprising an adjustable frame simulating a portion of a powered automotive window, the frame being adapted to receive one or more sets of window seals and a piece of window glass therein to simulate the sealing relationship between the seals and window glass in an actual automotive window. The testing machine further includes a drive mechanism for repetitively cycling the window glass through the frame and seals to simulate actual window operation over hundreds or thousands of cycles. The entire machine is preferably self-contained and portable, and the frame is further adjustable to be adapted to test different sets of seals and types of window glass.

Abstract: A stone pecking damage analyzer is provided which includes an enclosure frame. A pivotal first conveyor wheel is also provided. Spaced from the fixed conveyor wheel is a second conveyor wheel. A conveyor belt is fitted upon the two conveyor wheels. An automotive tire/wheel combination is mounted for rotation in contact with the conveyor belt planar surface. A variable speed motor torsionally coupled to the shaft powers the tire/wheel combination. A tubular conduit delivers stones to the conveyor's planar surface. An aggravator manipulates the tubular conduit to increase the delivery of stones to the conveyor. A deflector is also provided for redirecting stones delivered to the tire by the conveyor and thereafter accelerated by the tire. A mounting system hangs an automotive vehicle coated body panel in a position commensurate to its position with respect to the vehicle wheel well.

Abstract: Slurry useful for wire-saw slicing has viscosity adjusted to 400-700 mPa·second at a shear speed of 2/second and of 50-300 mPa·second at a shear speed of 380/second. The viscosity of slurry is measured using a cone and plate type viscometer which can measure viscosity at different shear speeds. Since the slurry sufficiently flows into inner parts of grooves formed in an ingot and consumed for wire-saw slicing due to the viscosity controlled in response to the shear speed, the ingot can be efficiently sliced to wafers or discs.

Abstract: A stone pecking damage analyzer is provided which includes an enclosure frame. A pivotal first conveyor wheel is also provided. Spaced from the fixed conveyor wheel is a second conveyor wheel. A conveyor belt is fitted upon the two conveyor wheels. An automotive tire/wheel combination is mounted for rotation in contact with the conveyor belt planar surface. A variable speed motor torsionally coupled to the shaft powers the tire/wheel combination. A tubular conduit delivers stones to the conveyor's planar surface. An aggravator manipulates the tubular conduit to increase the delivery of stones to the conveyor. A deflector is also provided for redirecting stones delivered to the tire by the conveyor and thereafter accelerated by the tire. A mounting system hangs an automotive vehicle coated body panel in a position commensurate to its position with respect to the vehicle wheel well.

Abstract: An apparatus for measuring abradability of a sample comprises a rotating drum with a rough surface and a means for contacting a sample with the rough surface while the drum is rotating. The sample may be caused to rotate relative to the drum, and to translate across the drum while the drum is rotating. Environmental controls may be used to control the temperature and the atmospheric conditions of the test. In the method of the invention, energy consumed by contact between the sample and the drum, as well as the weight loss of the sample, may be measured.

Abstract: A method and device for determining abrasive forces is disclosed. In order to determine the forces, at least two removable and distinguishable layers are applied on top of each other to a substrate or base so as to cover one another. Each layer requires a predetermined abrasive force for penetrating and removing the layer by scraping. The strength or force that is required is smaller the closer to the surface the layer is positioned. When the layers are subjected to abrasive forces, parts of the applied layers are scraped off, starting from the outermost layer and further downwards into the underlying layers. In this manner, one of the layers is exposed at each point, thereby indicating the abrasive force at that point. The exposed surface of each layer may then be identified. The method and device are particularly suitable in car-crash testing in order to assess the abrasive forces arising from airbags.

Abstract: A bench testing system creates a predetermined wear and friction environment wherein wear elements, illustratively a piston ring and a cylinder liner, can be tested, along with lubricant properties, under simulated conditions of an internal combustion engine. The effects of speed and normal load can be examined under multiple lubrication regimes, and variations in the coefficient of friction can be observed as a function of crank angle degree. Profilocorder techniques are used to examine photomicroscopic surface characteristics. The cylinder wall wear element is supported in a first support arrangement that is driven reciprocatingly along a substantially axial path. A dynamic counter-reciprocating arrangement is coupled thereto for controlling second harmonic inertial forces. A second support arrangement that supports the piston ring wear element is coupled to a linear drive that urges same in a direction transverse to the substantially axial path of reciprocation of the cylinder wall wear element.

Abstract: The invention sets forth a method for determining the hand quality of a fabric or other material. The invention establishes a new constant value to be applied to this determination. The constant value is referred to as the Quality Energy Value (hereinafter the “QE value”) of a material. The QE value takes into account the reciprocatory motion actually used when rubbing a piece of cloth with a finger to subjectively determine the hand quality of a fabric. The invention utilizes a testing apparatus which simulates this sliding motion of finger on fabric. The QE value also advantageously takes into account the velocity at which the frictional properties of the fabric are measured. It has been found that the lower the QE value, the better the quality of the fabrics. Accordingly, using the method of the invention, a range of QE values may be established for a variety of fabrics, and, thereby, the relative hand qualities of the fabrics may be compared.

Abstract: A novel Stewart platform includes electromagnetic linear actuators. The motion platform may be included in an apparatus and method for testing footwear where a stationary shoe is struck by the motion platform.

Abstract: Apparatus 10 (FIG. 1), for testing samples of friction material 31, 32 in rubbing contact with a surface 33 of a rubbing element 34, comprises a table 12 for supporting the rubbing element and a load cell 16 for sensing the load imposed by the frictionally coupled rotating samples from which the coefficient of friction can be determined. To make the tests repeatable rapidly and with identical starting conditions cooling means 40 is interposed between the rubbing element and table. Cooling means 40 comprises a fluid cooled heat exchanger 41, conveniently cooled by local main supply water supplied at its natural temperature, and thermoelectric cooling means 75. The thermoelectric cooling means consists of an array of planar peltier cooling elements which develops a temperature gradient there across which, with reference to the heat exchanger temperature, is able to cool and re-cool the rubbing element to temperatures as low as −25° C. within a matter of minutes.