Abstract:
A centrifuge temperature pre-calibration apparatus including a memory storage device having correction coefficients for temperature, a controller, an un-calibrated temperature sensor and a calibrated temperature display device connected to a computer which based on data from these connections calculates a slope of a line and calculates actual temperature based on this slope and an offset value. The slope is determined by the ratio of the difference between a second data point and a first data point of the calibrated temperature display device and the difference between the second data point and the first data point of the un-calibrated temperature sensor.
Abstract:
A mounting apparatus in which the vertical, lateral and torsional stiffness of the mounting apparatus are greater than the pivot stiffness. The greater stiffnesses are produced either by loading columns in tension or compression or by bending a rectangular column along its narrow, higher moment of inertia face.
Abstract:
A method and apparatus for a centrifuge energy management system prevents the energy level of a rotor from exceeding a predetermined containment limit for the centrifuge by monitoring the energy level and either terminating a run operation of the centrifuge if it surpasses the containment limit or reducing the rotational speed of the rotor.
Abstract:
A support substrate having an array of magnetically responsive sensors is mounted within the housing of a brushless DC motor in a plane perpendicular to the axis of the motor shaft having commutating magnets thereon. A ferromagnetic flux concentrating member in the form of a generally planar disc having an annular rim with radially inwardly directed spokes is mounted to the support substrate. Each spoke has a radial gap therein. A magnetically responsive sensor is received within each radial gap. The gap may divide the spoke into two discrete gap segments, or may alternatively form an enclosed recess with generally radially extending sidebars along each lateral edge of the spoke. The flux concentrating member conducts magnetic flux emanating from one magnetic pole to and through each of the magnetically responsive sensors and returns the flux to the other pole, such that, as the shaft is rotated, each of the magnetically responsive sensors is at substantially all times under the influence of magnetic flux emanating from one of the commutating magnets.
Abstract:
A centrifuge rotor has a central hub with a mounting recess therein, a ring disposed concentrically about the hub, the ring having a plurality of cavities formed therein, and a relatively thin web connecting the hub and the ring. The web defines a localized region which exhibits a stress therein that is greater than the stress present in any other portion of the rotor when the rotor is operating at the predetermined operating speed, so that, over operation time, the probability that rotor failure will occur only in the web is enhanced. The cavity ring has an annular rim with an upper surface having a predetermined reference line defined thereon. A portion of the upper surface of the rim defined relative to the reference line is relieved. The radial location of the relieved portion of the upper surface with respect to the reference line is governed in accordance with the axial position of the web with respect to the center of mass of the ring.
Abstract:
A centrifuge rotor includes a structural member having a plurality of receptacles therein. When the covert is attached to the body of the rotor the receptacles communicate with a respective one of the cavities disposed in the body of the rotor.
Abstract:
An electric motor system includes an electric motor, a temperature sensor mounted therein capable of measuring a local temperature and generating a temperature related signal, and a processor configured to calculate an actual temperature of a rotor magnet from the temperature related signal, and an actual output torque from the actual rotor magnet temperature. A method for determining the actual output torque of a motor includes sensing a temperature within the motor, calculating a rotor magnet temperature from the sensed temperature, and calculating the actual output mechanical torciue from the rotor magnet temperature.
Abstract:
Methods and apparatus for a centrifuge control system, which are particularly suited for automatically calibrating a centrifuge imbalance detector that include an accelerometer and a controller. The controller is configured to automatically calibrate imbalance limits. Upon determining these limits, the controller assigns these limits or values to the accelerometer.
Abstract:
A centrifuge rotor is provided with a pair of projections frangibly connected thereto. As the rotor reaches a predetermined speed the projections simultaneously fracture forming projectiles which puncture the evacuated chamber in which the rotor is mounted. Ambient air is drawn into the chamber, thereby windage limiting the speed of the rotor. The projections are each sized and positioned to impart a total unbalance less than the multiplication product of 0.5 gram-inches times the weight of the rotor.
Abstract:
A method and apparatus is herein disclosed for determining the motor performance of an electric motor through monitoring the temperature of rotor magnets. The temperature is determined by initially heating the rotor magnets to two known temperatures and subsequently recording the temperature at each known temperature. From the known and recorded temperatures, an offset, if any, is calculated. An actual temperature is then determined from the subsequent temperatures of the magnets and the offset. The actual temperature is then used as a basis to determine the motor performance.