The Perkin-elmer Corporation

Perkin-elmer Corporaton

John J Staunton

Larkin B Scott

An improved melting point temperature standard includes a well for receiving a temperature sensor to be calibrated. Surrounding the well is a cell with a crystalline material therein. A thermally conductive spacer contacts the outer cell walls. A thermal barrier contacts the spacer and a second thermally conductive member encircles the barrier. A heating/cooling element contacts the second thermally conductive member to apply heat or to cool it. Thermistors in the second thermally conducive member and the spacer are used by a control circuit to adjust the heat flow into the cell so that the crystalline material melts over a period of 7 to 8 hours making use of the temperature standard possible for many hours.

Temperature standard

An improved slide holder for use with a clinical spinner comprises a support having a channel defined in the top thereof transverse to the vertical axis of rotation of the support. Rapid rotation of the support with a slide positioned over the channel effects a partial vacuum in the channel which tends to hold the slide tightly against the support. Mechanical stops and spring retainers may also be included to insure retention of the slide on the support. The design of the slide holder minimizes the formation of an aerosol during spinning. A disposable spin-off interception system cooperates with the slide holder's operating characteristics to effectively eliminate aerosol formed.

Aerosol-reducing slide holder system

In an error correcting system in which error corrections for each of a plurality of steps of an independent variable in a device which has an error dependent upon the independent variable are stored in a register in adjacent storage positions thereof and wherein a location marker differing from any stored correction value is also stored in the register and moved as said device steps so as to always be adjacent the correction corresponding to the step of the device, the correction values being stored for a range of the device between a first limit and a second limit, the device having a greater overall range than the range between said first and second limit and being able to go to a position below said first limit, loss of synchronization between the device and the location marker when the device is moved below said first limit is prevented by detecting when said location marker reaches said first limit and causing it to move in a direction from said first limit toward said second limit as said device is moved below said first limit and in a direction toward said first limit as said device is moved from below said first limit back toward said first limit and again reversing the direction of movement of said location marker when said first limit is again reached with said independent variable moving in a direction toward said second limit permitting synchronization to be maintained even when going below the range for which correction values are stored.

System for maintaining below range synchronization in error correcting

Control of test chambers or specimens to stabilized temperatures at set points over a wide temperature range is accomplished with improved response time by an arrangement of cascaded Peltier affect heat pumps. Generally, power to a first Peltier unit in the arrangement is controlled relatively to the temperature deviation of the specimen from the desired set point, while power to a second Peltier unit therein is controlled proportionally to the temperature differential across the first Peltier unit. In applicatons where large thermal losses to ambient occur, a portion of the power control signal to the second Peltier unit is applied to offset the temperature set point as a compensation for such losses. Improvement in approach to stabilized temperature is further attained by applying an anticipation signal in proportion to the temperature gradient between the specimen and the first Peltier unit to decrease the monitored deviation of the specimen temperature from the set point. For system protection the power control signals to the Peltier units are shut off to preclude thermal runaway in applications where the specimen temperature is monitored by a sensor which must be exposed to ambient conditions during set-up periods.

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Oak Park, IL, United States of America

John J Staunton