| 摘要 |
1,170,796. Microtomes. SHANDON SCIENTIFIC INDUSTRIES Ltd. Feb. 16, 1968 [Feb. 17, 1967], No. 7744/67. Heading G2J. A microtome has a specimen holder 22 and a knife holder 42 contained within a box 10 made of plastics insulating material and having conduits 58, 59 through which a cold dry relatively inert coolant, such as nitrogen, can be introduced into the chamber in either its gaseous or liquid state so as to fill the chamber with cold dry gas and to flush air and water vapour from the chamber through the bleed passage. The knife holder has a trough 54 for receiving liquid nitrogen and a platinum resistance thermometer and resistance heater 56. The specimen holder Fig. 3 (not shown) also has a trough (28), a thermometer (31) and a heater (34<SP>1</SP>). A solenoid valve in each conduit and the resistance heaters are connected to a suitable automatic control unit and controlled by the thermometers to maintain a selected temperature within the box. A syringe 53 is provided to maintain an adequate supply of liquid in the boat 52 attached to the knife. The operation of the microtome is viewed through a transparent top cover 18 provided with a heater 20 to stop condensation. The specimen holder has an attachment member which extens through the wall of the box, sectioning movement being permitted by a flexible polyethylene or silicone rubber diaphragm 38. |
