Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
  • B04B—CENTRIFUGES
  • B04B15/00—Other accessories for centrifuges
  • B04B15/02—Other accessories for centrifuges for cooling, heating, or heat insulating

Definitions

• This invention relates to centrifuges. More ⁇ over, this invention discloses a process whereby a cen ⁇ trifuge can remotely determine the radiometer view fac ⁇ tor of differing shaped rotors and remotely cool a ro- tor and necessarily a contained sample to a precise temperature for centrifuging.
• Centrifuging must occur at precise sample temperature for optimum results.
• the preferred temperature at the sample and rotor is usually 0° C.
• radiometers To determine precisely rotor temperatures, radiometers are utilized. These radiometers view the rotor, and determine the temperature of the rotor. Where the rotor is not at the precise temperature, a large surrounding refrigerating can is utilized. By maintaining the temperature of the can at differential with respect to the temperature of the rotor, the rotor can be brought down to the specific temperature required for centrifuging.
• radiometers do not just view the rotor when determining the temperature of the rotor.
• the radiometers also view the surrounding refrigerating can.
• the amount of the rotor that is viewed and the amount of the surrounding refrigerating can that is viewed vary. This variation is dependent upon many factors including the shape of the rotor, the material of which the rotor is constructed, the thermal emissions of the can and the like.
• the view of the radiometer of the rotor and the view of the radiometer of the surroundin ⁇ refrigerating is expressed as a ratio. This ratio is a constant and is known as the "view factor" of the radio ⁇ meter for a particular rotor.
• a method of centrifuge calibration which permits rapid and accurate refrigera ⁇ tion of the rotor containing the sample is disclosed.
• a rotor with sample to be centrifuged is placed within a centrifuge can.
• Temperature of the radiometer T ⁇ ITS., and temperature of the surrounding refrigerating can T is determined at a first time, t Q .
• temperature of the radiometer T_ CL, and the temperature of the surrounding refrigerating can T are equilibrated with the resultant thermodynam ⁇ ics causing the radiometer to seek the temperature of the rotor.
• the temperature excursion between t n and t.. for the temperatures of the radiometer T and the tern- perature of the refrigerating can T are measured to yield respective ⁇ T ITS. and and ⁇ Tc.
• TjTca./ ⁇ TC is taken to give a constant which comprises the view factor from the radiometer for the particular shape of rotor and the surrounding can. Thereafter, the temperature of the rotor Tr will equal the tempera- ture of the radiometer plus the difference in tempera ⁇ ture between the refrigerating can T and the radiometer
• An object of this invention is to disclose a method of rotor calibration which will automatically calibrate any rotor placed in a centrifuge.
• the method enables rapid cooling to a precise processing tempera ⁇ ture of a sample contained within the rotor. It is not necessary or required for the centrifuge operator to insert any rotor parameters. Thus, centrifuge opera ⁇ tion can occur even where rotors of third party suppli- ers are utilized.
• a further object of this invention is to dis ⁇ close a software operated optimum cooling cycle for centrifuged samples.
• a flow diagram can sample program listings for the disclosed method of optimum cooling is provid ⁇ ed. This software requires no input of rotor parame ⁇ ters; it is only necessary that the disclosed cycle occurs.
• Fig. 1 is a side elevation section of a typi ⁇ cal centrifuge illustrating schematically in broken lines two typical rotor configurations with differing "view factors" and illustrating schematically thermal instrumentation for monitoring the can, refrigerating the can, and determining the temperature of the rotor; and
• Fig. 2 is a side elevation section at the radiometer of the instant invention illustrating ⁇ che- matically the view factor of the radiometer.
• a centrifuge is schemati ⁇ cally illustrated.
• a refri ⁇ eratin ⁇ can C completely surrounds a rotor R.
• Can C is sealed at the top by a vacuum tight seal through wall 16.
• the can C is typically refrigerated electrothermally by apparatus not shown.
• a sample S within the rotor R is centrifuged about a spin axis 20 at extreme high rotational velocities. Such velocities can reach 100,000 revolutions per minute.
• Fig. 1 it can be seen from the side elevation of Fig. 1 that more than one rotor R is illustrated.
• the first rotor R (shown in solid lines) has a low profile and is immediate the bottom wall 22 of the can C.
• a second rotor R.. is illustrated in broken lines. This rotor is elevated with respect to the bottom surface 22 of can C.
• the radiometer includes at least one bimetallic connection from an electrical lead 30 passing through a radiometer body 33 to a heat absorbing disk 35.
• a bime ⁇ tallic electrical junction at 37 on disk 35 electrically transmits to lead 39 the temperature.
• FIG. 2 Viewing the radiometer of Fig. 2, two arrows schematically illustrate the "view” that disk 35 has of the environment relating to either rotor R or rotor R..
• a first view indicated by arrow V- is in the direction of the respective rotor.
• a second arrow V 2 is in the direction of the can C sidewalls. Stopping at this juncture and referring to the view of Fig. 1, it can be seen that when rotor R is substituted and rotor R. is placed in the centrifu ⁇ e this so-called “view” will change. With the higher profile rotor it will naturally be expected that the radiometer T will have a greater solid angle of view of the can C. This problem is not merely a function of rotor shape. Specifically, the heat content of the rotors, color of the rotors, and even the sample can all change the variations of "view" of the radiometer T.
• ⁇ T to ⁇ T is taken to give a constant.
• This "view factor” is for a particular shape, color, and kind of rotor.
• the temperature of the rotor T will equal the temperature of the radiometer minus the tem ⁇ perature of the radiometer T plus the temperature of the refrigerating can T C- times the determined view fac- tor. It may be expressed:
• Tr ⁇ ra + ⁇ (T c -T ra )
• the can will be equilibrated with the rotor. Typically, this equilibration will precise ⁇ ly occur at the processing temperature.
• the disclosed calibration cycle takes less less than 3 mins. When compared to typical rotor cool ⁇ ing times, in the order of several hours, the automated calibration process here disclosed is possible because rotor will change less than .1°C during the process. i will also be realized that the disclosed process is capable of being microprocessor .based.

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Priority Applications (3)

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Publications (1)

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ID=21982379

Family Applications (1)

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Citations (4)

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• 1987
  • 1987-05-22 US US07/053,171 patent/US4833891A/en not_active Expired - Fee Related
• 1988
  • 1988-05-17 CA CA000566985A patent/CA1308404C/en not_active Expired - Lifetime
  • 1988-05-22 JP JP1989600022U patent/JP2589770Y2/ja not_active Expired - Lifetime
  • 1988-05-22 WO PCT/US1988/001425 patent/WO1988009219A1/en active IP Right Grant
  • 1988-05-22 DE DE8888904358T patent/DE3864382D1/de not_active Expired - Fee Related
  • 1988-05-22 HU HU883495A patent/HU205566B/hu not_active IP Right Cessation
  • 1988-05-22 EP EP88904358A patent/EP0316382B1/en not_active Expired
• 1998
  • 1998-05-14 JP JP003269U patent/JPH11118U/ja active Pending

Patent Citations (4)

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