WO2001085350A1

WO2001085350A1 - Apparatus and method for temperature sensing of an element of a rotating platter

Info

Publication number: WO2001085350A1
Application number: PCT/US2001/013221
Authority: WO
Inventors: John M. Stoughton
Original assignee: Umm Electronics, Inc.
Priority date: 2000-05-10
Filing date: 2001-04-25
Publication date: 2001-11-15
Also published as: AU2001253792A1

Abstract

The present invention relates to a method and an apparatus for sensing the temperature of an element of a rotating platter (20). The apparatus includes a collimated optical pyrometer positioned such that light emitted from an element (32) of the rotating platter is preiodically visible to the optical pyrometer (40). A pluralitery of optical windows (24) are formed in the rotating platter and a reference body (42) is positioned opposite the rotating platter from the optical pyrometer such that light emitted from the reference body is periodically visible to the optical pyrometer through the optical windows. The reference body and the elements of the rotating platter are chosen to have substantially the same emissivities. The reference body is maintained at the temperature the elements of the rotating platter are desired to be controlled to, such that a controller (50) connected to the optical pyrometer and to heaters (30) operationally coupled to the platter elements can determine the temperature of the elements relative to the reference body and send control signals to the respective heaters to maintain the elements at the same temperature as the reference body.

Description

APPARATUS FOR TEMPERATURE SENSING OF AN ELEMENT OF A ROTATING PLATTER

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to optical thermodynamics and, more particularly, to an apparatus for remotely detecting and comparing the temperatures of two moving bodies of the same or similar eniissivities.

BACKGROUND OF THE INVENTION

Chemical analysis techniques are commonly used to generate medical data about biological fluids, such as blood and urine. Most chemical analyses of biological fluids are currently performed away from the patient care site at specialized analytical laboratories. The analytical process usually consists of the physician drawing one biological fluid sample from the patient for each test desired, sending the samples away to a centralized location for analysis, and waiting for the results to come back. The process is expensive, time consuming, and prone to communications error since both the sample and the results have to pass through several different people. Moreover, many samples have short shelf lives necessitating a rushed turnaround time that can foster mistakes. A delay in processing the sample might mean having to draw yet another sample from the patient. Further, it is advantageous to the patient that the test results are obtained as quickly as possible, since the patient can begin receiving treatment only after his condition has been properly diagnosed. One alternative to sending fluid samples away for electrochemical and or reflectance analysis has been developed in the form of the automatic field analysis unit. A number of miniature field analysis units for automatically conducting electrochemical tests on biological fluids are known, such as those described in the claims and specifications of U.S. Patent Application Number 09/248,607 for a "Cartridge-Based Analytical Instrument with Optical Detector", U.S. Patent Application Number 09/248,614 for a "Cartridge-Based

Analytical Instrument with Rotor Balance and Cartridge Lock/Ejection System", and U.S. Patent Application Number 09/248,737 for a "Cartridge-Based Analytical Instrument Using Centrifugal Force/Pressure for Mechanical Transport of Fluids". Typically, such miniature chemical testing units include disposable chemical test cells or cartridges containing reagents and into which a predetermined amount of fluid sample is placed for reaction and analysis.

It is important that the chemical data so generated by the analysis unit be accurate, since it will be used as the basis of a medical diagnosis. To this end, it is often important to the kinetics of the chemical reactions that they be performed at predetermined temperatures. It is therefore important that each sample test cartridge loaded into the analysis apparatus be maintained at a predetermined temperature for the duration of the analysis sequence. The temperature of the individual test cartridges may be measured by a thermocouple or other dedicated temperature sensor operationally connected to each cartridge. While thermocouples/temperature sensors offer an accurate measure of the temperature of each cartridge, they are expensive (often using precious metal components) and each requires a dedicated controller channel.

Moreover, the rotation/translation of the testing platform tends to disengage the placement of dedicated sensors, so fewer electrical connections to the platform means less down time of the system for repair. There is therefore a need for an accurate, precise, and inexpensive temperature detection system for determining whether each test cartridge is being maintained at the desired analysis temperature. The present invention addresses this need.

SUMMARY OF THE INVENTION

The present invention relates to method and apparatus for remotely measuring the temperature of one or more sample bodies on a rotating platform relative to a reference body maintained at a known or desired reference temperature. The apparatus includes a collimated optical pyrometer and a reference body maintained at a constant reference temperature. The reference temperature is preferably the temperature at which the sample bodies are desired to be maintained. The reference body and the sample bodies are chosen to have substantially the same emissivities. The sample bodies are attached to a rotatable platter having one or more optical windows formed therein. The sample bodies are positioned the same radial distance from the center of the platter (axis of rotation) as the optical windows. As the platter rotates, the optical pyrometer alternately receives radiation emitted from the reference body (through the optical windows) and the sample bodies. The optical pyrometer then produces output signals proportional to the intensities of the radiations respectively received. An electronic controller is connected to the optical pyrometer, and detects the output signals generated by the optical pyrometer. The electronic controller is also connected to heaters positioned in thermal communication with the respective sample bodies, and sends respective control signals to the heaters to maintain the desired temperature of each sample body.

One form of the present invention relates to a system for remotely sensing and controlling the temperature of elements of a rotating platter.

One object of the present invention is to provide an improved method of remotely controlling the temperature of one or more moving elements. Related objects and advantages of the present invention will be apparent from the following description. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a first embodiment remote temperature sensing apparatus of the present invention.

FIG. 2 is a schematic view of a second embodiment remote temperature sensing apparatus of the present invention.

FIG. 3 is a schematic view of a third embodiment remote temperature sensing apparatus of the present invention.

FIG. 4 is a schematic view of a fourth embodiment remote temperature sensing apparatus of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.

BRIEF THEORY OF RADIATION PYROMETRY

All physical objects radiate electromagnetic energy. The intensity and average wavelength of the radiation so emitted is a function of the temperature of the object. The peak wavelength of the emitted radiation decreases with increasing object temperature, while the intensity of the radiated energy increases with increasing object temperature. Below about 1200 °F (about 650 °C) an object radiates electromagnetic energy of wavelengths too long to be visible to the naked eye (i.e., in the infrared to radio portion of the electromagnetic spectrum). Above about 1200 °F (about 650 °C) an object begins to radiate in the visible portion of the electromagnetic spectrum (i.e., it becomes incandescent). As the temperature of the object increases, the average wavelength of the radiated energy shortens, and the visible portion of the energy radiated therefrom changes in hue from a deep red, through orange and yellow, until it becomes white at about 2200 °F (about 1200 °C). As this happens, the intensity of the emitted electromagnetic radiation increases very rapidly, such that by the time white light emission is achieved the light is too intense to be safely viewed by the naked eye. Not all objects at a given temperature emit radiation having the same peak wavelength or intensity. In other words, the emissivity of an object is a correction factor used to standardize the temperature- induced electromagnetic radiation emissions to those of an ideal (blackbody) emitter. The emissivity of an object is defined as the ratio of power per unit area radiated from the object to that radiated from an ideal emitter at the same temperature. Emissivity may be influenced by the composition of the object, the angle of view of the object, and the shape and texture of the emitting surface, among other factors. The above-described phenomenon by which objects emit electromagnetic radiation having temperature dependent intensity and peak wavelength characteristics is the basis of a temperature measurement technique called radiation pyrometry (or optical pyrometry when limited to the visible spectrum). In general, radiation pyrometers function by measuring the peak wavelength of the emitted radiation, the intensity of the emitted radiation, or a combination of both. Radiation pyrometers commonly use a photocell or a thermopile (a number of series-connected thermocouples) to generate a voltage characteristic of the intensity of the electromagnetic radiation incident thereon, and are typically calibrated to function in a narrow region of the electromagnetic spectrum. Since different objects radiate different characteristic peak wavelengths and intensities at different temperatures, precise temperature measurements are difficult to make pyrometrically and necessarily involve a correction for the emissivity of the measured object or objects. In order to compare the temperatures of two objects through radiation pyrometry, it is first necessary to either know the emissivities of both bodies or to know that both bodies have the same emissivity. If both bodies have the same emissivity, direct comparisons of the peak wavelengths and/or intensities of the radiations emitted therefrom may be made to determine their temperatures relative to each other.

DETAILS OF A CHEMICAL MEASUREMENT INSTRUMENT A typical portable fluid chemistry analysis instrument is an automated diagnostic tool adapted for use at a patient treatment site, such as a doctor's office or clinic. The typical portable fluid chemistry analysis instrument includes a power source, a platter or carousel for holding a plurality of disposable test cartridges, an analysis assembly for optically or otherwise measuring the chemical reactions and/or reaction products within the test cartridges, a motor for turning the carousel to sequentially introduce the test cartridges to the analysis assembly, and an electronic controller for tracking the test cartridges, collecting the raw data, and generating, coordinating, and storing data points. The instrument can typically perform a number of different chemical analyses on stationary test cartridges by introducing the analysis assembly to the test cartridge and measuring the rate of a given chemical reaction therein. The test cartridges are typically disposable and pre-loaded with everything required for the test except the fluid sample upon which the desired tests are to be performed. As most chemical reaction rates are nontrivially temperature dependent, the cartridges must be maintained at a uniform and constant predetermined temperature in order for the results of the analyses to be precise, accurate, and repeatable. Therefore, it is important to maintain the test cartridges at a predetermined desired temperature during the course of the analyses.

DESCRIPTION OF THE INVENTION FIG. 1 illustrates a first embodiment of the present invention, a remote temperature sensing apparatus 10 adapted to measure the relative temperature of a moving body or of an element of a moving body. In this embodiment, the apparatus includes a rotatable platter 20 having a primary axis of rotation 22. Preferably the platter 20 has the shape of a substantially flat and circular disk. Optical windows 24 are formed in the platter 20 and positioned a predetermined radial distance from the axis of rotation 22. The optical windows 24 are adapted to allow desired wavelengths of electromagnetic radiation, such as light, to pass freely through the platter 20 disk (i.e., in a direction substantially parallel to the axis of rotation 22) and may or may not contain a solid pane transparent to the desired wavelengths of radiation. Preferably, a plurality of optical windows 24 are provided in the platter 20, although configurations including a single optical window 24 or none at all are also contemplated. A plurality of receptacles 26 are formed in the platter 20 and positioned substantially the same radial distance from the axis of rotation 22 as the optical windows 24. Preferably, the receptacles 26 and the optical windows 24 are spaced apart evenly at about the same radial distance from the axis of rotation 22, and alternate with one another around the circumference of the platter 20, although they may be spaced and positioned in any convenient manner. A motor 28 is connected to the platter 20 to actuate platter rotation. Each receptacle 26 may also include its own heater 30, such that the temperature of each receptacle 26 may be independently controlled. Alternately, some or all of the receptacles 26 may be in thermal communication with one or more common heaters 30. The receptacles 26 of this embodiment are formed to lockingly receive elements 32 to be maintained at a desired temperature. In this embodiment, the platter elements 32 are cartridges 32 containing chemical reagents and fluid samples to be analyzed. Other embodiments are contemplated wherein chemical reagents and unknown samples are deposited directly into the receptacles 26, such that the filled receptacles 26 themselves act as the platter elements 32. Still other embodiments are contemplated wherein the receptacles 26 are adapted to receive other types of elements 32 desired to be controlledly heated and spun. A radiation pyrometer 40 is positioned on one side of the platter

20 disk and an independently heatable reference body 42 is positioned opposite the pyrometer 40 (relative to the plane of the platter 20). The radiation pyrometer 40 is preferably a collimated optical pyrometer. The optical pyrometer 40 and the reference body 42 are positioned substantially the same distance from the axis of rotation 22 as the optical windows 24 and the receptacles 26, such that when an optical window 24 is rotated between the optical pyrometer 40 and the reference body 42, the reference body 42 is visible to the optical pyrometer 40 through the window 24. The optical pyrometer 40 and the reference body 42 are preferably positioned such that a line connecting the two intersects the platter 20 at a substantially right angle, although the optical pyrometer 40 and the reference body 42 may occupy any positions convenient to the apparatus design so long as the reference body 42 is periodically visible to the optical pyrometer 40. The reference body 42 is preferably connected to a reference body heater 44 and a temperature sensor 46 (such as a thermocouple, a thermistor, an RTD, or the like), such that the reference body may be independently and precisely maintained at a desired temperature. However, the desired temperature of the reference body 42 may be maintained by any convenient means. The reference body 42 and the cartridges 32 (or other elements to be maintained at the desired temperature) have, by design, substantially the same emissivities. Therefore, the reference body 42 is preferably maintained at the desired temperature of the cartridges 32. An electronic controller 50 is operationally connected to the motor 28, the receptacle heaters 30, the optical pyrometer 40, the reference body heater 44 and the reference body temperature sensor 46. The electronic controller 50 is programmed to receive signals from the thermocouple 46 corresponding to the temperature of the reference body 42. The reference body heater 44 may then be controlled by the controller 50 until the thermocouple 46 indicates the desired reference temperature. The electronic controller 50 is also programmed to actuate rotation of the platter 20 at one or more predetermined speeds. The electronic controller 50 is further programmed to receive signals from the optical pyrometer 40 corresponding to the relative temperatures of the reference body 42 and the respective cartridges 32. The electronic controller 50 can compare the relative temperature of the reference body 42 to that of each respective cartridge 32, and send a control signal to each respective cartridge heater 30 to maintain the respective cartridge 32 at the desired temperature. In other words, if the signal from the optical pyrometer 40 correlating to the temperature of the reference body 42 is stronger than the signal correlating to the temperature of a particular cartridge 32, the electronic controller 50 may send a control signal to that cartridge's heater 30 increasing its output. Likewise, if the signal from the optical pyrometer 40 corresponding to the temperature of a particular cartridge 32 is stronger than the signal corresponding to the temperature of the reference body 42, the electronic controller may send a control signal decreasing the output of that cartridge's heater 30. In the case of analog control, the electronic controller 50 may send a control signal that is proportional to the magnitude of the difference between the signals correlating to the temperatures of the reference body 42 and the cartridge 32. The electronic controller 50 may control the temperature of each cartridge 32 through an iterative method, through a more precise digital control method, or any method convenient to the power of the electronic controller 50.

Those skilled in the art will recognize that the reference body 42 may have a different emissivity than the cartridges 32, so long as the emissivity ratio between the two is known. This will allow the cartridge heater 30 to be adjusted until the optical readings taken with the optical pyrometer 40 from the cartridge 32 and the reference body 42 indicate equivalent temperatures after correcting for the (known) different emissivities. Another contemplated embodiment of the present invention, illustrated in FIG. 2, includes the use of a movable mirror 52A to alternately direct light from one or more reference bodies 42A and from one or more moving or stationary sample bodies 32A to an optical pyrometer 40A. Still another contemplated embodiment of the present invention includes the use of a plurality of radiation pyrometers 40B and or reference bodies 42B to control a plurality of platter elements 32B to a plurality of different temperatures, as shown in FIG. 3. Yet another contemplated embodiment of the present invention, shown in FIG. 4, includes a radiation pyrometer 40C having a plurality of possible orientations and adapted to view a plurality of reference bodies 42C to control a plurality of elements 32C to a plurality of distinct temperatures. In this embodiment, the elements 32C may be mounted on a platform (either moving or stationary) and may have any convenient shape.

METHOD OF CONTROLLING PLATTER ELEMENT TEMPERATURE Referring back to FIG. 1, the rotatable platter 20 is situated in line between a collimated optical pyrometer 40 and a heatable reference body 42. The platter 20 includes optical windows 24 formed therein through which the reference body 42 is periodically visible to the optical pyrometer 40 when the platter 20 is rotating. The optical pyrometer 40 is operationally connected to an electronic controller 50.

The at least one heatable sample body 32 is then attached to the platter 20 such that when the platter 20 is rotated, the at least one heatable sample body 32 is periodically visible to the optical pyrometer 40. The at least one heatable sample body 32 preferably has substantially the same emissivity as the reference body 42. The platter 20 is then rotated to a predetermined speed, and the at least one heatable sample body 32 is heated. The optical pyrometer 40 periodically measures the radiation emitted from the reference body 42 and from the at least one heatable sample 32. The data from the optical pyrometer 40 is transmitted to the electronic controller 50, which compares the signal from the optical pyrometer 40 correlating to the reference body 42 to the signal from the optical pyrometer 40 correlating to the at least one heatable sample body 32. The electronic controller 50 then decides whether the at least one heatable sample body 32 is hotter than, cooler than, or at the same temperature as the reference body 42. The electronic controller 50 sends a signal to the heater 30 associated with the at least one heatable sample body 32 to adjust the heater 30 until the radiation emitted therefrom is of substantially equal intensity and/or peak wavelength as the radiation emitted from the reference body 42. It should be noted that if a Peltier-type heater 30 is chosen, the sample body 32 may actually be cooled by reversing the flow of current through the heater 30.

While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are to be desired to be protected.

Claims

Claims:What is claimed is:

1. An apparatus for measuring the temperature of a sample cartridge connected to a rotating platter, comprising: a collimated optical pyrometer; a rotatable platter having an axis of rotation; a plurality of optical windows formed in the rotatable platter; a reference body having a first emissivity; an intersection point defined as the point where a line extending from the reference body to the optical pyrometer perpendicularly intersects the platter; a sample cartridge having a second emissivity; at least one sample cartridge receptacle formed in the platter and adapted to receive the sample cartridge; wherein the sample cartridge receptacle, the optical windows, and the intersection point are all substantially radially equidistant from the axis of rotation; wherein the first and second emissivities are substantially equal; wherein the reference body is maintained at a desired temperature; and wherein the sample cartridge is to be maintained at the desired temperature while the platter is rotated.

2. The apparatus of claim 1, further comprising: a motor operationally connected to the rotatable platter; a first heating element operationally connected to the reference body; a second heating element operationally connected to the sample cartridge; and an electronic controller operationally connected to the motor, the optical pyrometer, and the second heating element; wherein the motor is adapted to rotate the platter; wherein the optical pyrometer is adapted to send a first signal to the electronic controller corresponding to a reference body temperature and is adapted to send a second signal to the electronic controller corresponding a sample cartridge temperature; wherein the electronic controller is adapted to compare the first signal to the second signal; wherein the electronic controller is adapted to send a temperature-increasing control signal to the second heating element when the first signal exceeds the second signal by a first predetermined amount; and wherein the electronic controller is adapted to send a temperature-decreasing control signal to the second heating element when the second signal exceeds the first signal by a second predetermined amount.

3. The apparatus of claim 2 wherein the value of the control signal is indicative of the magnitude of the difference between the first signal and the second signal.

4. The apparatus of claim 1 wherein there are a plurality of sample receptacles and a plurality of sample cartridges.

5. The apparatus of claim 2 further comprising a temperature sensor operationally connecting the reference body and the electronic controller and adapted to provide the electronic controller with a reference body temperature signal.

6. The apparatus of claim 5 wherein the electronic controller is adapted to receive a reference body temperature signal from the temperature sensor and wherein the electronic controller is adapted to send a reference body temperature control signal to the first heating element to maintain the reference body at a desired temperature.

7. The apparatus of claim 1 further comprising: a second reference body having a third emissivity; a second collimated optical pyrometer; a second intersection point defined as the point where a line extending from the second reference body to the second optical pyrometer perpendicularly intersects the platter; a plurality of sample cartridge receptacles formed in the platter and adapted to receive the sample cartridge; a plurality of sample cartridges filling a plurality of respective sample cartridge receptacles; wherein the plurality of sample cartridge receptacle, the optical windows, and the first and second intersection points are all substantially radially equidistant from the axis of rotation; wherein the first, the second and the third emissivities are substantially equal; wherein the second reference body is maintained at a second desired temperature; and wherein at least one sample cartridge is to be maintained at the second desired temperature while the platter is rotated.

8. The apparatus of claim 1 further comprising: a motor operationally connected to the rotatable platter; a first heating element operationally connected to the reference body; a second heating element operationally connected to the sample cartridge; an electronic controller operationally connected to the motor, the optical pyrometer, the first heating element, and the second heating element; and a temperature sensor operationally connecting the reference body and the electronic controller and adapted to provide the electronic controller with a reference body temperature signal; wherein there are a plurality of sample receptacles and a plurality of sample cartridges; wherein the motor is adapted to rotate the platter; wherein the optical pyrometer is adapted to send a first signal to the electronic controller corresponding to a reference body temperature and is adapted to send a second signal to the electronic controller corresponding to a sample cartridge temperature; wherein the electronic controller is adapted to compare the first signal to the second signal; wherein the electronic controller is adapted to send a temperature-increasing control signal to the second heating element when the first signal exceeds the second signal by a first predetermined amount; wherein the electronic controller is adapted to send a temperature-decreasing control signal to the second heating element when the second signal exceeds the first signal by a second predetermined amount; wherein the electronic controller is adapted to receive a reference body temperature signal from the temperature sensor; wherein the electronic controller is adapted to send a reference body temperature control signal to the first heating element to maintain the reference body at a desired temperature; and wherein the values of the respective control signals are proportional to the magnitude of the differences between the first signal and the second signal.

9. An apparatus for controlling the temperature of a moving body comprising: a platform; at least one sample body connected to the platform; at least one heater connected in thermal communication to the respective plurality of sample bodies; a reference body maintained at a desired temperature; a collimated optical pyrometer positioned to sequentially optically interrogate the respective reference body and at least one sample body and adapted to send at least one output signal corresponding to the respective temperatures of the respective reference body and at least one sample body; and an electronic controller operationally connected to the optical pyrometer and to the at least one heater; wherein the electronic controller is adapted to receive the at least one output signal from the optical pyrometer corresponding to the respective temperatures of the respective reference body and the at least one sample body; and wherein the electronic controller is adapted to send at least one temperature control signal to the respective at least one heater to maintain the respective at least one sample body at the desired temperature.

10. The apparatus of claim 9 wherein the platform is adapted to move.

11. The apparatus of claim 9 wherein the reference body and the at least one sample body have the same emissivities.

12. The apparatus of claim 10 wherein the platform further includes an axis of rotation and wherein the platform is adapted to rotate about the axis of rotation.

13. The apparatus of claim 12 further comprising at least one optical windows formed in the platform and wherein the at least one sample body is positioned substantially radially equidistant from the axis of rotation and wherein the optical pyrometer is positioned to optically interrogate the reference body through the at least one sample window.

14. The apparatus of claim 9 wherein the optical pyrometer is adapted to move to sequentially interrogate the respective reference body and the at least one sample body.

15. The apparatus of claim 14 further comprising a plurality of reference bodies maintained at a respective plurality of desired temperatures and a plurality of sample bodies and wherein the optical pyrometer is adapted to move to sequentially interrogate the respective plurality of reference bodies the plurality of sample bodies.

16. The apparatus of claim 9 further comprising: a second reference body maintained at a second desired temperature; wherein the collimated optical pyrometer is positioned to sequentially optically interrogate the respective second reference body and at least one sample body and adapted to send at least one output signal corresponding to the respective temperatures of the second respective reference body and at least one sample body heated by at least one respective sample body heater ; wherein the electronic controller is adapted to receive the at least one output signal from the optical pyrometer corresponding to the respective temperatures of the respective second reference body and the at least one sample body; and wherein the electronic controller is adapted to send at least one temperature control signal to the at least one respective heater to maintain the respective at least one sample body at the second desired temperature.

17. The apparatus of claim 9 further comprising: a reference body heater operationally connected to the electronic controller; and a thermocouple operationally connecting the electronic controller to the reference body; wherein the reference body and the at least one sample body has substantially the same emissivities; wherein the electronic controller is adapted to interrogate the thermocouple to determine the temperature of the reference body; wherein the electronic controller is adapted to send a reference body temperature control signal to the reference body heater to actuate maintenance of the desired temperature of the reference body; and wherein the electronic controller is adapted to send at least one temperature control signal to the respective at least one heater to maintain the respective at least one sample body at the respective desired temperatures.

18. The apparatus of claim 9 further comprising a pivotable mirror positioned to alternately provide optical communication between the collimated optical pyrometer and the reference body and between the optical pyrometer and the at least one sample body.

19. A method for controlling the temperature of an element of a moving platform, comprising the steps of: a) providing a collimated optical pyrometer; b) providing a rotatable platter having optical windows formed therein through which a reference body maintained at a desired temperature is visible to the optical pyrometer; c) providing a reference body having a desired emissivity; d) attaching at least one heatable sample body having substantially the same emissivity as the reference body to the rotatable platter; e) rotating the platter; f) measuring the radiation emitted from the reference body; g) measuring the radiation emitted from the at least one heatable sample body; and h) adjusting the temperature of the at least one heatable sample body until the radiation emitted from the at least one sample body is substantially equal to the radiation emitted from the reference body.

20. A method for controlling the temperature of an element of a moving platform, comprising the steps of: a) providing a collimated optical pyrometer; b) providing a rotatable platter having optical windows formed therein through which a reference body maintained at a desired temperature is visible to the optical pyrometer; c) providing a reference body having a first emissivity; d) attaching at least one heatable sample body having a second emissivity as the reference body to the rotatable platter; e) rotating the platter; f) measuring the radiation emitted from the reference body; g) measuring the radiation emitted from the at least one heatable sample body; and h) adjusting the temperature of the at least one heatable sample body until the radiation emitted from the at least one sample body is substantially proportional to the radiation emitted from the reference body.