Abstract: A controlled atmosphere incubator having an interior chamber surrounded by a heated water jacket. A glass access door of the chamber is directly heated by a clear, electrically conductive coating. The door is sealed against the perimeter of the opening by a readily replaceable gasket and is field reversible due to unique hinge mounting assemblies. An easily accessed blower assembly is located within the chamber and includes a HEPA filter readily replaceable by the user from within the chamber. A filtered air exchange system is provided for limiting the maximum level of humidity in the chamber. The incubator control maintains constant power output from the blower motor so that the heat output of the motor is also constant. A voltage compensated temperature control is also provided for the heaters associated with the water jacket. Compensation for environmental conditions inside the chamber is also provided by the control for producing more accurate readings of carbon dioxide levels.

Abstract: A cooling device for rapidly cooling items, such as biological samples. The cooling device includes an enclosure having a chamber and an air circulation path at least partially within the chamber. A fan is operatively connected to the chamber for circulating air within the air circulation path and a perforated tube is disposed within the air circulation path for receiving a liquid refrigerant under pressure and distributing refrigerant in gaseous form to the air circulation path. Preferably the perforated tube is formed as a coil having multiple revolutions and either an axial blade fan or a centrifugal fan is received generally within the coils.

Abstract: A safety cabinet having a work area defined by an enclosure and including an air circulation and cleaning system. The air circulation and cleaning system includes a plurality of air plenums and passageways through which air is circulated by a blower assembly. A portion of the air exiting the blower is directed through a transition boot and exhaust plenum and a remaining portion of the air exiting the blower assembly is directed into the work area through a perforated divider plate and a supply plenum. The transition boot between the exhaust and supply plenums include resealable fasteners disposed along a seam between first and second ends thereof and around a first end thereof which is attached to the exhaust plenum.

Abstract: A cryogenic storage apparatus including housing, inner storage tank which may contain cryogenic fluid such as liquid nitrogen, and a lid which is used to access the storage tank. The lid preferably completely seals the storage tank when in a closed position, and includes a vent path formed between the storage tank and ambient. This vent path leads to the rear of the housing. A flap valve is mounted to the exit point of the vent path to allow escape of evaporated liquid nitrogen as necessary.

Abstract: A controlled atmosphere incubator having an interior chamber surrounded by a heated water jacket. A glass access door of the chamber is directly heated by a clear, electrically conductive coating. The door is sealed against the perimeter of the opening by a readily replaceable gasket and is field reversible due to unique hinge mounting assemblies. An easily accessed blower assembly is located within the chamber and includes a HEPA filter readily replaceable by the user from within the chamber. A filtered air exchange system is provided for limiting the maximum level of humidity in the chamber. The incubator control maintains constant power output from the blower motor so that the heat output of the motor is also constant. A voltage compensated temperature control is also provided for the heaters associated with the water jacket. Compensation for environmental conditions inside the chamber is also provided by the control for producing more accurate readings of carbon dioxide levels.

Abstract: A cryogenic storage apparatus including housing, inner storage tank which may contain cryogenic fluid such as liquid nitrogen, and a lid which is used to access the storage tank. The lid preferably completely seals the storage tank when in a closed position, and includes a vent path formed between the storage tank and ambient. This vent path leads to the rear of the housing. A flap valve is mounted to the exit point of the vent path to allow escape of evaporated liquid nitrogen as necessary.

Abstract: An upright split door, ultra low temperature freezer which includes a single chamber cooled by a cold wall refrigeration system and accessible by separate upper and lower doors. The refrigeration system maintains the chamber at a substantially constant, ultra low temperature, such as within the range of about -50.degree. C. to -90.degree. C. Short term items may be stored in and accessed from an upper portion of the chamber by the upper door without causing the very cold air in the freezer chamber from spilling out the lower portion of the chamber. Long term items may be stored in the lower portion of the chamber and accessed by the lower door. A horizontal mullion is mounted to the freezer side walls and extends between the two doors to provide a seal for respective lower and upper edges of the two doors. A self-regulating heater strip is disposed within the mullion between upper and lower resilient sealing bulbs extending horizontally to prevent condensation build up in the mullion area.

Abstract: A test tube rack assembly including a test tube rack pivotally connected to a base having end support structure for allowing pivoting motion of the test tube rack with respect to a stationary base about a horizontal axis. A selectively actuable connector is affixed to at least one of the base end supports and includes a stud selectively engageable with one of a plurality stud receivers associated with the test tube rack for pivoting movement therewith. Each of the stud receivers defines a different angular position of the test tube rack with respect to the base. Preferably, a holder is disposed between the base and the test tube rack. A pair of holder end supports, comprising spring plates, have locking and alignment structure which mates with structure on the ends of the test tube rack to allow releasable, secure engagement between the holder and the rack.

Abstract: An upright split door, ultra low temperature freezer which includes a single chamber cooled by a cold wall refrigeration system and accessible by separate upper and lower doors. The refrigeration system maintains the chamber at a substantially constant, ultra low temperature, such as within the range of about -50.degree. C. to -90.degree. C. Short term items may be stored in and accessed from an upper portion of the chamber by the upper door without causing the very cold air in the freezer chamber from spilling out the lower portion of the chamber. Long term items may be stored in the lower portion of the chamber and accessed by the lower door. A horizontal mullion is mounted to the freezer side walls and extends between the two doors to provide a seal for respective lower and upper edges of the two doors. A self-regulating heater strip is disposed within the mullion between upper and lower resilient sealing bulbs extending horizontally to prevent condensation build up in the mullion area.

Abstract: A console shaker which includes a shaker device mounted within a temperature and lighting controlled chamber and an air jacket which completely surrounds the chamber and also provides substantially laminar, HEPA-filtered air flow through the chamber in one direction. A refrigeration device and a heating device either cool or heat the air before it flows through the HEPA filter. The HEPA filter is mounted at the end of the chamber which defines an air inlet to the work chamber and an outlet is disposed at the opposite end of the chamber. The outlet end of the chamber receives air from both within the workspace of the chamber as well as from the front and rear air spaces of the air jacket. A microprocessor based control system provides an interface between the user and the various components for establishing the conditions within the chamber, such as shaker speed, temperature, time and lighting to be controlled by the user.

Abstract: An orbital shaker having an upper horizontal orbiting platform and including a counterbalancing mechanism for stabilizing forces associated with the orbiting mass. The counterbalancing mechanism counteracts the moment created by the orbiting mass in the X-Z plane of the upper orbiting shaft by way of a lower counterweight rotating in phase, but spaced from the Z coordinate of the shaker load. The lower counterweight is positioned low relative to the driven, rotating shaft and is preferably incorporated into the drive sheave of the shaker. An upper counterweight, sized to counter the mass of the load, platform, etc., above it and the lower counterweight below it in the X-Y direction is connected to the driven shaft located out of phase with the load and the lower counterweight and between the load and lower counterweight in the Z direction.

Abstract: A refrigeration system generally including a compressor, a condenser and an expansion device connected between the condenser and the low pressure, suction side of the compressor. A pressure control is disposed on the discharge or high pressure side of the compressor to selectively allow refrigerant to bleed from the high pressure side of the system. The control continuously monitors the pressure of the refrigerant discharging from the compressor and bleeds refrigerant off into a bypass, including an expansion tank and a bypass capillary tube, when a predetermined pressure is reached. The bypass capillary tube is connected between the expansion tank and the low pressure side or suction line of the system. When the control senses that the compressor discharge pressure has fallen below a preset pressure, the bleed off of refrigerant from the high pressure side of the system is stopped. Refrigerant vapor remaining in the bypass is slowly metered into the suction line due to a pressure differential therebetween.

Abstract: A safety cabinet having a work area enclosed by a hood structure and including an air circulation and cleaning system. The air circulation and cleaning system includes a plurality of air ducts and passageways through which air is circulated by a blower within the cabinet. A portion of the air exiting the blower is directed through an exhaust after passing through a first filter and the remaining portion of the air exiting the blower is directed through the work area after passing through a second filter. A pressure gauge is connected between the first and second filters for measuring the pressure differential between the two filters to give an indication of the loading and efficiency of the filters. A third filter is disposed upstream of the pressure gauge to remove airborne contaminants in the air flowing to the gauge to prevent such contaminants from leaking from the gauge.

Abstract: A biological safety cabinet comprising an enclosure having two side walls, a rear wall, a bottom wall defining a work surface, a top wall and a front window, below which access can be had to the work surface, the enclosure defining a work area. A plenum surrounds the enclosure and communicates with the work area. A blower induces a negative pressure within the plenum to circulate contaminated air through a filter within the enclosure, which creates a downwardly directed air curtain of work area air below the window. A vertically oriented outwardly facing channel section is secured to each side wall adjacent the window. Each channel section has a downwardly and forwardly sloping upper end, a rear edge of which extends above a lower edge of the window and a front edge of which extends below the lower edge of the window. The plenum communicates with each channel.

Abstract: A laboratory freezer appliance providing a usable storage space on the order of 5 to 20 cubic feet capable of storage temperatures of -160.degree. C. and lower including an insulated freezer chamber, heat transfer tubes in proximity to the freezer chamber carrying liquid argon at ultra-low temperatures which absorbs heat from the freezer chamber thereby vaporizing the argon in the heat transfer tubes; a closed cycle, hermetically-sealed free piston Stirling cycle heat pump providing a cold end above a vertical displacer driven by a linearly reciprocating piston at a delta T to the freezer chamber of about -13.degree. C.; a condensing chamber surrounding the cold end of the heat pump for condensing argon vapor to the argon liquid; and a distributor for distributing liquid argon from the condensing chamber to the heat transfer tubes and returning argon vapor to the condensing chamber, all without mechanical pumping of the argon, in a continuous, closed cycle refrigeration system.

Abstract: A biological safety cabinet vertical lift assist system employing one or more pneumatic springs operatively connected to the cabinet and sliding window to counterbalance the window's weight to provide a substantially constant brake force spring resulting in smoother and easier operation of the window.