US3828571A - Cover for microtome and ultramicrotome freezing chamber - Google Patents

Cover for microtome and ultramicrotome freezing chamber Download PDF

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Publication number
US3828571A
US3828571A US00394593A US39459373A US3828571A US 3828571 A US3828571 A US 3828571A US 00394593 A US00394593 A US 00394593A US 39459373 A US39459373 A US 39459373A US 3828571 A US3828571 A US 3828571A
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Prior art keywords
chamber
improvement
cover
passage
depression
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Expired - Lifetime
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US00394593A
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English (en)
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G Lechner
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C Reichert Optische Werke AG
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C Reichert Optische Werke AG
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/02—Devices for withdrawing samples
    • G01N1/04—Devices for withdrawing samples in the solid state, e.g. by cutting
    • G01N1/06—Devices for withdrawing samples in the solid state, e.g. by cutting providing a thin slice, e.g. microtome
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
    • G01N1/42—Low-temperature sample treatment, e.g. cryofixation

Definitions

  • Freezing chambers for microtomes and ultrami'crotomes generally comprise a rectangular box shaped. chamber with an external control and coolant supply.
  • the chamber may be cooled to a pre-selected temperature, which may be as low as about -l60C, by the controlled evaporation of a liquid coolant such as nitrogen.
  • a liquid coolant such as nitrogen.
  • One, and usually two or three, evaporation units are lo cated in the chamber.
  • one unit is so located as to cool the knife and one unit is so located as to cool the specimen arm with an optional unit toassist the first two in rapidly cooling the chamber- Two basic techniques have been heretofore. used.
  • closed freezing chamber is conventionally used when it' is possible to support, by a float liquid, specimens as they are cut.
  • float liquids must be selected from materials which remainliquid at the selected temperature and dimethyl sulfoxide mixed with water is an example of such a float liquid. It is apparent that the liquid, or mixture of liquids, selected must not only remain liquid at the selected temperature, but should not react with or otherwise adversely affect the specimens cut.
  • the closedchamber is the most efficient and effective device since the escape of the coolant is restricted and effects of variations inthe medium surroundingthe chamber are not significant.However, severe limitations caused by interaction between the float liquid and specimen as well as providing float liquids which do not freeze at extremely low temperatures significantly restrict the usefulness of closed chamber devices.
  • British patent No. 1,170,796' is one example of such a device and discloses someof the problems inherent therein.
  • the open chamber is used for thedry knife technique which requires removal of specimen sections as they are cut. This technique is used when sections may react with or be otherwise affected by liquids used to float sections as described above.
  • the open chamber is substantially the same as the closed chamber with the top removed to permit access to remove the sections as they are cut.
  • Such chambers are extremely inefficient since the unrestricted flow of gas escaping from the open topped chamber requires large quantities of coolant to maintain even nominally reduced temperatures in the area of the specimen and knife.
  • Such open chambers are also highly susceptible to fluctuations in temperature caused by air currents in the room, opening of doors and the like.
  • the aforementioned'British patent further discloses disadvantages of an open type chamber including the formation of ice crystals caused by condensation from the surrounding medium.
  • the freezing chamber of the present invention is distinguished by its cover having an elliptical opening in a conical depression in the cover.
  • the elliptical opening is defined by a plane bisecting the conical depression at an anglewith respect to the cover and positioned to provide working access to'remove sections as they are cut while sumultaneously minimizing the escape of coolant by having the area with the greatest depression near the rapid cooling unitof the freezing chamber to deflect the evaporating liquid away from theopening.
  • FIG. 1 is atop view of a freezing chamber in perspective
  • FIG. 2 is a top view of the cover for such a chamber.
  • FIG. 3 is a side view in cross-section of the cover.
  • a chamber body 1 of a conventional insulating material has a knife holder 2 mounted therein. Knife 3 is held in the holder by clamp 4 which may be manually tightened by locking screw 5. Knife adjustments are made by conventional micrometer means 6.
  • Specimen arm 7 has a specimen clamp 8 mounted thereon to carry a specimen 9 to be sectioned. The specimen arm extends through an opening 10 in the side of body 1 and the opening is closed by flexible seal '11: which permits movement of the arm 7 during the cutting operation.
  • Coolant for the knife is introduced through inlet 12 and conducted to knife cooling unit 13 by tubing 14.
  • Specimen arm 7 is cooled by unit 15 which is connected by passage 16 with coolant inlet 17. Rapid cooling unit 18 is connected to the coolant supply via tubing 19*and inlet 20 primarily to assist units 13 and 15 during the initial cooling cycle.
  • the selected reduced temperature for the sample is obtained by introducing coolant such as liquid nitrogen through inlets 12, 17 and 20 to cooling units 13, 15 and 18- where heat is absorbed by evaporation.
  • coolant such as liquid nitrogen
  • the cooling units and controls therefor may be of a conventional type including those taught in the aforementioned British patent and are well-known to those skilled in the art.
  • Cover 21 in FIG. 2 has an ellipsoidal opening 22 located therein at the base of a conical depressed area 23-.-.
  • The' edge 24 of depressed area 23 which defines opening 22 is asymmetrically located and in a plane which bisects cover 21 at an angle of about 5 to 15.
  • the location of opening 22 and the angle a of plane 25 provide a major lip area 26 and a minor lip area 27.
  • the larger depression in area 26 deflects the gas evaporating from rapid cooling unit 18 away from opening 22 without significant restriction of operator manipulating space within the area of the cutting knife.
  • gas evaporating from the specimen cooling unit 15 is deflected away from the opening. Deflection of gas evaporating from cooling unit 18 and opening.
  • the edge of the depression lies in a plane which bisects the cover at an angle of approximately 95 to produce a major-lip having a maximum depth of about 20 millimeters from the cover surface and a minor lip having a maximum depth of about millimeters from the cover surface.
  • the window opening being of a proportional size to the chamber volume and gas flow substantially elimi the knife and specimen the improvementcomprising I acover for said chamber, said cover having an upper surface, a conical depression in said upper surface, said depression having a continuous depending sidewall and a lowermost edge defining a passage through said cover, said edge being spaced from said upper surface and being in a plane bisecting the plane of said upper surface at an angle less thanabout l5 whereby the flow .of evaporating gas within said chamber displaces the atmosphere through said passage from the chamber without significant mixing.

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Sampling And Sample Adjustment (AREA)
  • Devices That Are Associated With Refrigeration Equipment (AREA)
US00394593A 1972-09-06 1973-09-05 Cover for microtome and ultramicrotome freezing chamber Expired - Lifetime US3828571A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT763872A AT330480B (de) 1972-09-06 1972-09-06 Kuhlkammer fur ultramikrotome

Publications (1)

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US3828571A true US3828571A (en) 1974-08-13

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US00394593A Expired - Lifetime US3828571A (en) 1972-09-06 1973-09-05 Cover for microtome and ultramicrotome freezing chamber

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US (1) US3828571A (de)
AT (1) AT330480B (de)
GB (1) GB1443237A (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4395075A (en) * 1982-03-24 1983-07-26 E. I. Du Pont De Nemours & Co. Misalignment system for a microtome
US4918941A (en) * 1989-05-16 1990-04-24 Board Of Regents, The University Of Texas System Cryogenic ultramicrotome seal
US5299481A (en) * 1990-09-11 1994-04-05 Leica Aktiengesellschaft Carrier arm seal for a microtome of ultramicrotome
DE19815696A1 (de) * 1998-04-08 1999-10-21 Gsf Forschungszentrum Umwelt Temperaturgeregelte Überströmapparatur für biologische Proben
US20130133342A1 (en) * 2011-11-29 2013-05-30 Leica Mikrosysteme Gmbh System for cooling a sample in an apparatus for processing the sample
USD1029916S1 (en) * 2022-11-07 2024-06-04 Hongfeng Liu Camera base
US12336550B2 (en) 2019-02-05 2025-06-24 Cremmjoy Inc. Frozen confection machine

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3462969A (en) * 1966-09-08 1969-08-26 Fritz Grasenick Microtome using liquid refrigerant
US3495490A (en) * 1967-02-17 1970-02-17 Shandon Scient Ind Ltd Microtome freezing attachment

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3462969A (en) * 1966-09-08 1969-08-26 Fritz Grasenick Microtome using liquid refrigerant
US3495490A (en) * 1967-02-17 1970-02-17 Shandon Scient Ind Ltd Microtome freezing attachment

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4395075A (en) * 1982-03-24 1983-07-26 E. I. Du Pont De Nemours & Co. Misalignment system for a microtome
US4918941A (en) * 1989-05-16 1990-04-24 Board Of Regents, The University Of Texas System Cryogenic ultramicrotome seal
WO1990014585A1 (en) * 1989-05-16 1990-11-29 Board Of Regents, The University Of Texas System Cryogenic ultramicrotome seal
US5299481A (en) * 1990-09-11 1994-04-05 Leica Aktiengesellschaft Carrier arm seal for a microtome of ultramicrotome
DE19815696A1 (de) * 1998-04-08 1999-10-21 Gsf Forschungszentrum Umwelt Temperaturgeregelte Überströmapparatur für biologische Proben
DE19815696C2 (de) * 1998-04-08 2000-06-29 Gsf Forschungszentrum Umwelt Temperaturgeregelte Überströmapparatur für biologische Proben
US20130133342A1 (en) * 2011-11-29 2013-05-30 Leica Mikrosysteme Gmbh System for cooling a sample in an apparatus for processing the sample
US12336550B2 (en) 2019-02-05 2025-06-24 Cremmjoy Inc. Frozen confection machine
USD1029916S1 (en) * 2022-11-07 2024-06-04 Hongfeng Liu Camera base

Also Published As

Publication number Publication date
ATA763872A (de) 1975-09-15
DE2328298B2 (de) 1976-09-16
AT330480B (de) 1976-07-12
GB1443237A (en) 1976-07-21
DE2328298A1 (de) 1974-03-28

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