Abstract: A ceramic encased thermocouple placed within a kiln electrically controls an array of signal classifiers which, in turn, control the operation of the kiln heating elements. The temperature value at which the classifier array terminates the whole kiln heating operation is preselected as one of a plurality of discrete predetermined values corresponding to pyrometric cone temperature values.

Abstract: The frequency of an electronic oscillator is controlled by a crystal located in the oven. The heaters in the oven include resistance elements for quick warm-up, and steady state. The circuit allows the quick warm-up power to be reduced incrementally as the set temperature is approached and effects a smooth transition to the steady-state heater. This is accomplished by circuit features which reduce the control loop gain when high power is applied to the heaters and increase the gain as the warm-up power decreases.

Abstract: A domestic range of the electric type includes a cooking platform providing a plurality of "burner" locations constituted by pancake-shaped surface heating elements formed of spirally wound resistance wire. An elongated boxlike control unit extends upwardly from and across the back edge of the cooking platform. An oven chamber of the pyrolytic self-cleaning type is located below the range platform and includes radiant-type heating elements also formed of resistance wire. A heat-sink-mounted electronic module located within the control unit is protected from damaging high temperatures caused by improper operation of the range by a pair of normally closed temperature-sensitive bimetal actuated switches mounted to the module heat sink, the switches being connected in electrical series relationship between the heating elements and their electrical power source.

Abstract: A gravity switch for automatic control of an operative cycle in an appliance, such as a toasting cycle in a toaster oven or the like, includes an imbalanced weight member interposed between a displaceable member that moves in accordance to operation of the cycle and mechanical component parts operative between an OFF position and an ON position. During ON cycle operation, the imbalanced weight member is directly supported against the pull of gravity by the displaceable member. When the cycle operation reaches completion, the displaceable member is sufficiently moved so as to cause the release of the imbalanced weight member which is then free to move under the influence of gravity. This gravitional action initiates an interaction among the mechanical component parts resulting in quick return to the OFF position causing the cycle operation to rapidly terminate.

Abstract: A temperature controlled oven apparatus having a central chamber with a heater element and a pivotal inner baffle door, located within a removable outer access door, periodically opened or closed to regulate the exhaust of oven air and the admission of ambient air into the oven through a preheated plenum chamber.

Abstract: An electric oven toaster construction wherein an interrupt mechanism is provided for interrupting operation of a toast timer controller when the oven toaster door is opened. An interrupt lever is positioned between a door operated rod and a heat-up/cool-down bi-metal timer controller so that when the door is opened the interrupt lever moves the toasting period controller to its off position. Thus, when the door is opened during a toasting cycle operation, the toasting period controller is returned to its off position so that a user is required to reset a new full-toast cycle when the door is reclosed. This arrangement prevents undertoasted bread that could result if fresh bread is inserted in the middle of a toasting cycle.

Abstract: A method and apparatus for controlling the heating of toast in a toaster oven broiler. The adjustment shaft for the thermostat which controls the baking and broiling modes receives a circular dial having toast color indications thereon corresponding to light, medium and dark toast colors. The dial is rotatable on the thermostat shaft under the control of a bimetal strip which responds to temperature changes in the oven cavity. As the oven temperature increases during each successive toasting cycle, the dial rotates and at the end of the cycle indicates the thermostat setting that will achieve the desired toast color for the next toasting cycle.

Abstract: A method of food heating control in which the heating time length (.tau..sub.o) from a time point (t.sub.1) when the food temperature changing with the heating thereof reaches a predetermined set value (T.sub.1) to a time point (t.sub.2) when the vapor or gas liberated by heating of the food begins to increase the humidity or gas concentration is used as a basis for automatically determining a subsequent heating time length (.tau..sub.R). Since the time period (.tau..sub.R) for the subsequent heating process is determined by the heating time from the time point when the food temperature reaches a predetermined set value to the time point when the humidity or gas concentration begins to increase (unlike in the prior art method in which the heating time from the start of heating to the time point when humidity begins to increase is used to determine the subsequent heating time), the error in the heating time which otherwise might be caused by the variation in the initial food temperature is obviated.

Abstract: An L-shaped hooked end of a latch rod, rotatably supported by a range body, engages a door-supported cam surface as the rod is rotated on its longitudinal axis by a motor to effect oven door locking. The cam surface is fixed at and radially spaced from the center of an elongated member whose ends are fastened to the oven door. As the latch hook engages and rides the cam surface, the elongated member is placed in torsion to provide a biasing force that maintains the locked oven door in tight sealing engagement with the range body. The motor rotating the latch rod to effect oven door locking and unlocking is actuated solely by operator manipulation of the oven thermostat control apart from the oven selector and timer controls.

Abstract: A temperature control system for an electronically-controlled thermal cooking oven having a single oven temperature sensor, which system facilitates varying the calibration set point in the field for normal cooking modes, without affecting the self-cleaning temperature calibration which is factory preset. A sensor-developed analog voltage is employed to control self cleaning temperature in the oven, with the oven temperature during normal cooking modes, such as bake and broil, controlled by the same voltage modified by an independently developed offset value or signal. The required summing of the sensor voltage and the offset voltage preferably is done by means of a suitably-programmed microprocessor-based control system. With this arrangement, the offset can be changed to vary the set point for normal cooking modes without affecting the self-cleaning temperature which is detected solely by the sensor, and cannot be readily varied by field adjustment.

Abstract: Baking oven including chamber walls defining a baking oven chamber, a door for closing off the chamber, a broiler heating element and at least one further heating element being disposed in vicinity of opposite chamber walls, and air blowing and guiding means disposed between the heating elements for generating an air stream being in the middle of the chamber and at least approximately parallel to and maintained at a given distance from the chamber walls.

Abstract: An electric oven comprises a base made of a heat-resisting material and provided with a meat support member, an outer case removably rested on a stepped portion of the peripheral wall of the base, a reflector disposed within the outer case in the neighborhood of a ceiling thereof to define an upper radiating chamber and a lower heating chamber, a heat generator provided within the heating chamber, and a hot air fan also provided within the heating chamber and serving to transfer heat generated from the heat generator as hot air into a roasting chamber defined within the outer case. The hot air fan is driven from a drive motor, which also drives a cooling fan disposed within the radiating chamber. The outer case is provided with a switch means for closing and opening an electric circuit connecting a power source to the heat generator and motor for driving the hot air fan and cooling fan such that the electric circuit is closed when the outer case is placed on the base and opened when the outer case is raised.

Abstract: A latch control arrangement for a self-cleaning oven or similar thermostatically controlled apparatus is provided to efficiently and safely control the locking and unlocking of the oven door. The self-cleaning oven is of the type that includes an oven temperature control circuit having a sensing element arranged to sense the temperature of the oven cavity. The oven temperature control circuit is responsive to manually operable selector arrangements of the oven including oven temperature and oven mode selection arrangements. In one arrangement, the oven controls are provided by a rotatable selector control. The latch control arrangement in one embodiment includes a locking member to lock a manually operable oven door latch. A locking member verification switch is provided to sense the portion of the locking member that extends into interfering relationship with the latch member.

Abstract: A toaster-oven appliance has a control circuit which enables a user to program the operation of the appliance through a keyboard with audible feedback and which includes functional keys for selecting one mode of operation from available BAKE, BROIL, SLOW COOK, TIMER and TOAST modes, and numerical keys for entering a temperature, time interval and toast color. The BAKE and BROIL functions may be used with the TIMER function to provide TIME-BAKE and TIME-BROIL functions. An interactive digital display is provided to display a user selected function, temperature, time interval, or an error indication in the event that an impermissible entry is made. In the presently preferred embodiment that is described, the control circuit includes microprocessor-based programmable digital logic. The microprocessor operates under the direction of a master program.

Abstract: A food warming and cooking cabinet comprising a housing having infrared reflective material on the interior surface, a source of infrared radiation located inside the housing and a support for a plurality of trays adapted to carry food thereon. The source of infrared radiation comprises two vertically oriented tubular infrared lamps located on opposite sides of the housing with the tray support therebetween. Each lamp is located in a recess in opposed side walls. The infrared reflective material is polished aluminum.

Abstract: A latch control arrangement for a self-cleaning oven or similar thermostatically controlled apparatus is provided to efficiently and safely control the locking and unlocking of the oven door. The self-cleaning oven is of the type that includes an oven temperature control circuit having a sensing element arranged to sense the temperature of the oven cavity. The oven temperature control circuit is responsive to manually operable selector arrangements of the oven including oven temperature and oven mode selection arrangements. In one arrangement, the oven controls are provided by a rotatable selector control. The latch control arrangement in one embodiment includes a locking member to lock a manually operable oven door latch. A locking member verification switch is provided to sense the portion of the locking member that extends into interfering relationship with the latch member.

Abstract: A proportional oven having two heaters mounted to a thermally conductive base stabilizes the temperature of a temperature sensitive crystal mounted on the thermally conductive base by adjusting the ratio of powers applied to the two heaters.

Abstract: An electrically heated oven for mobile vehicles, such as vans or recreational vehicles, includes a tightly closed oven compartment divided by an internal, imperforate, vertical secondary wall spaced from the back wall of the oven into a front cooking chamber and a rear heater chamber. A thermostatically controlled, plate-like, low wattage electric resistance heating element operable at the vehicle voltage is located within the heater chamber intermediate the upper and lower edges of the secondary wall, which edges are spaced from the top and bottom walls of the oven to allow convection air flow between the cooking and heater chambers. The front surface of the secondary wall is dull and roughened to readily dissipate heat into the cooking chamber and the rear surface of the secondary wall is smooth and shiny to minimize absorption of heat thereby from the heating element. The oven is mounted from a face plate for easy installation into the vehicle.

Abstract: A control arrangement is provided for a self-cleaning oven or similar thermostatically controlled apparatus. The self-cleaning oven in one arrangement is of the type that includes a manual latching arrangement operated by a handle for latching a pivotally mounted front door of the oven. The self-cleaning oven also includes a temperature control circuit having a sensing element arranged to sense the temperature of the oven cavity. The oven temperature control circuit is responsive to manually operable selector arrangements of the oven including oven temperature and oven mode selection arrangements. In one arrangement, the oven controls are provided by a rotatable selector control. The control arrangement includes a locking arrangement for the door latch to automatically lock the door latch arrangement whenever the oven door latch is closed and to unlock the door latch predetermined operating modes when the oven temperature is below a predetermined temperature.

Abstract: A door opening mechanism for partially opening a door on a toaster oven wherein the oven includes a thermal timer for controlling the operation of the oven in a toast mode. The door opening mechanism includes a first lever held in a first position by the timer wherein the first lever is released upon termination of the toast mode. The mechanism further includes a resiliently biased slide held in a first position by the first lever and released to a second position upon completion of the toast mode. The slide is mechanically coupled to a lever assembly that includes second and third levers and a cam lever. The third lever and the cam lever are mechanically coupled to the oven door and are resiliently held in a first position to hold the door closed and resiliently moved to a second, door open position upon release of the first lever. The mechanism turns the mode selector switch to the off position once the toast has been removed from the oven and the door closed.

Abstract: A pyrolytically cleaned domestic cooking oven including a catalyst for combustion of the smoke evolved during cleaning, and a temperature sensor placed inside the catalyst and arranged to regulate the heating control of the oven during pyrolytic cleaning.

Abstract: A heat-up/cool-down bimetal timer for an electric toaster wherein a unique screw fastener is provided for holding a calibration adjustment screw without being deformed during automated adjustment of the screw. The fastener is made from a blade of spring sheet metal that has an end turned on itself in the form of a cylinder for holding the calibration screw. Thus, the axis of the screw is parallel to or even in line with a plane that lies midway between the planes of the major surfaces of the sheet metal fastener. Accordingly, any automated screw driving equipment that may push downwardly on the head of the screw for adjusting it normally would not flex or bend the fastener in a plane perpendicular to one of its major flat surfaces.

Abstract: An electric oven toaster construction wherein a terminal assembly is provided for mounting a U-shaped temperature sensing device on an oven toaster wire rack so that the rack may be removably inserted in the oven toaster and the sensing device will be readily electrically connected in a control circuit of the oven toaster when the rack is positioned in the oven toaster.

Abstract: An automatic cleaning arrangement for a glass-ceramic cooking surface which is adapted to remove baked-on soils from the surface regions surrounding the individual cooking areas by the process of oxidation. Additional thin film heaters are located under the regions to be cleaned and are activated by a timer controlled power supply circuit. An interlock switch in the cook heater line disables the cook heater when the cleaning operation is in progress. The power supply circuit for the thin film heaters is arranged to disable automatically the cooking heaters when a break occurs in the glass-ceramic surface in the region of the thin film heaters.

Abstract: A tunnel oven includes a framework forming an elongated cooking tunnel with an entrance at one end for ingress of products to be heated in the tunnel during traverse through the tunnel and an exit at the opposite end for egress of heated products. A conveyor of either in-line type with over-and-under reaches or a return type with coplanar reaches conveys products from the entrance to the exit. The tunnel floor is a plate constituting a hearth. Infrared radiant heater panels along the tunnel length above and below the hearth provide heat. Pairs of thermocouples arranged in two sets, each set having an upper and lower thermocouple, to provide sensing of the temperatures of the hearth and the upper heating elements.

Abstract: Regulation of the temperature of a pyrolitically cleaned cooking oven during cleaning to avoid local overheating of the oven base plate enamel. A heating-up power level is used until near the pyrolitic temperature, and then a lower power level is used for maintaining the oven at about the pyrolitic cleaning temperature. The change over takes place preferably at about 470.degree. C.

Abstract: An oven is disclosed adapted to heat a food item of the type having a crust portion and a filler portion lying on the crust portion, characterized in that a first electrical heating member, adapted for substantially constant heating operation at a predetermined temperature, is stationed in the oven adjacent the crust portion, and a second heating member, having a greater thermal intensity than the first heating means and adapted for substantially brief heating operation at a temperature higher than the predetermined temperature, is stationed in the oven adjacent the filler portion.

Abstract: A method and apparatus for drying clothes wherein a clothes dryer is operated at a low level of energy input for a major portion of a drying cycle, followed by a high energy input for a short period near the end of the drying cycle. A single heater provides both levels of energy input, and has associated control means to operate the heater at the different input levels. For example, an electric heater element is controlled by cam actuated switches to operate at two levels of voltage input or a gas burner is provided with two solenoid actuated valves which are also controlled by cam actuated switches to operate the burner at two different levels of fuel input.

Abstract: A baking oven having a baking chamber preferably divided into a plurality of baking compartments disposed in a vertical stack separated from one another by a deck and enclosed by a cabinet having an access door. Each such deck comprises top and bottom plates with a space therebetween and a heating element therein spaced from said plates. The deck is provided with a narrow vent to said space across its width adjacent the access door. A sensing bulb or other temperature sensing means of a thermostat is located in the said space with the sensing tip of the sensing means being substantially at said vent. The top surface of the bottom plate is selectively blackened and the heating element is located to provide progressively less heating toward the back of the baking compartments. The top side of the baking chamber is defined by a like deck and the bottom side of the baking chamber is defined by a similar deck which does not have a blackened lower plate.

Abstract: A control device includes a housing having a serpentinely disposed channel and a cover, secured to the housing, which converts the channel into an ultrasonic waveguide. One end of the waveguide is bounded by a stationary reflector and the other end of the waveguide communicates with a bore which holds a piezoelectric device matched to the waveguide so as to provide therein, when actuated, a propagating transverse wave in the ultrasonic frequency range. The cover includes three elongated slots, each of which slidably supports a different reflector unit. Each unit has a reflector extending into the waveguide and can be positioned anywhere along its corresponding slot. Actuation of the piezoelectric transducer by an electrical pulse causes an ultrasonic pulse to propagate down the waveguide and parts thereof are reflected back to the transducer where an electrical group of pulse signals are caused to appear.

Abstract: In a first embodiment, a control device includes a housing having a serpentinely disposed channel and a cover, secured to the housing, which converts the channel into an ultrasonic waveguide. One end of the waveguide is bounded by a stationary reflector and the other end of the waveguide holds a piezoelectric transducer matched to the waveguide so as to provide therein, when actuated, a propagating transverse wave in the ultrasonic frequency range. The cover includes a plurality of slots communicating with the waveguide, each slot being located at a different position along the propagation path of the waveguide; and a plurality of resiliently mounted reflectors, each reflector being associated with a different one of the slots and being insertable into the waveguide by, for example, fingertip pressure. Actuation of the transducer by an electrical pulse causes an ultrasonic pulse to propagate down the waveguide.

Abstract: An oven with a fixed-elevation single-shelf for uniformly cooking three or more meat roasts to substantially equal, even, and uniform levels of doneness, centering them within an average 10.degree. F. parameter temperature zone under 212.degree.. Apparatus and procedures subject all of the roasts to substantially equal, even, uniform, and low density heat from naturally ambient (non-mechanically-induced movement) air.

Abstract: A door opening mechanism for partially opening a door on a toaster oven wherein the oven includes a thermal timer for controlling the operation of the oven in a toast mode. The door opening mechanism includes a first lever held in a first position by the timer wherein the first lever is released upon termination of the toast mode. The mechanism further includes a resiliently biased slide held in a first position by the first lever and released to a second position upon completion of the toast mode. The slide is mechanically coupled to a lever assembly that includes second and third levers and a cam lever. The third lever and the cam lever are mechanically coupled to the oven door and are resiliently held in a first position to hold the door closed and resiliently moved to a second, door open position upon release of the first lever. The mechanism turns the mode selector switch to the off position once the toast has been removed from the oven and the door closed.

Abstract: In a gas chromatography system of the type including an oven for the GC column, and an electric heater for controllably heating the oven; an improved system is disclosed for controllably opening and closing the oven door to enable a fully controlled heat leak, thereby to stabilize the oven temperature at a desired set point. A signal indicative by first or second conditions of an oven temperature above or below the set point is generated. A heater power control responds to one of the signal conditions by effecting heating of the oven. Bi-directional door motor and actuator means are provided for opening and closing the oven door over a prescribed operating range, and these means are enabled to operate for a predetermined period upon the signal in its first or second condition departing from preset threshold values for a predetermined period whereby closing or opening of the oven door is effected in incremental steps.

Abstract: An electric oven toaster construction wherein a unique inverted L-shaped lever is provided for controlling operation of an oven toaster switch and a toaster timer. The lever is pivotally mounted at the intersection of its legs and a generally horizontal leg extends outwardly from the oven toaster to a position where it may be manually actuated. The other leg extends downwardly for moving the toaster timer to its on position. The generally horizontal leg of the lever includes a downwardly extending latch arm which is movable into engagement with a solenoid armature for holding the lever and the switch in a closed position during a toasting cycle. Thus, at the end of a toasting cycle, the toaster timer actuates the solenoid to release the latch arm and a spring bias of the switch moves the switch and the inverted L-shaped lever to an open position.

Abstract: A potter's oven includes an electrical heating element for controlling the temperature in the oven. Power to this heating element is controlled by a bimetallic switch and an electrically energized heater therefor and the percentage of power supplied to the oven heating element is controlled in dependence upon the value of resistance in series with the heater for the bimetallic switch. The value of this resistance is increased in stepwise fashion under control of at least one sensor which determines the outside wall temperature of the oven, the temperature at which the sensor responds being chosen to cause the temperature inside the oven to reach a predetermined value and to hold such value for a predetermined time.

Abstract: A heat generating device, such as an oven, includes a heating element connected to a power source and a fuse interposed therebetween. The fuse is effective, when the magnitude of the current flowing thereto exceeds the fuse rating, to disconnect the element from the source. A thermostat is included in the circuit to control the current flow and, thus, the temperature level. In the event of a malfunction of the thermostat, temperature responsive means are effective, when the temperature sensed thereby exceeds a given level, to increase the current flowing through the fuse beyond the fuse rating. The temperature responsive means includes a temperature sensitive switch and a resistive element which may be a second heating element. When the switch is closed by excessive temperature, the resistive element is placed in parallel with the heating element, thus lowering the effective resistance of the circuit to increase the current.

Abstract: The disclosed cooking device has a cooking cavity with an access opening and a door for closing same, and has a rack in the cavity to support the food to be cooked. The device has electric heating elements in the cavity, and control means that energize the heating elements approximately 10 to 45% of potential high level heat outputs thereof. The total power input of the low level energized heating elements is in the range of 15 to 30% maximum and thus provides heating of air in the cavity only to within the range of 220.degree. to 300.degree. F maximum, without food load, and at a low rate so that the cavity air temperature generally will only exceed the temperature of the food by 20.degree. to 50.degree. F aproximately during a sustained cooking cycle. This low temperature method of cooking does not require personal tending to the food and minimizes the chances of burning the food.

Abstract: An electric oven toaster construction wherein a unique manually operable lever, latch lever, and catch lever are provided for controlling operation of an oven toaster main switch and an oven toaster timer. The manually operable lever is provided with a lug for actuating the latch lever to release the catch lever to stop the operation of the toast timer and open the main switch without opening the oven toaster door. The manually operable lever is also provided with a pin which is uniquely positioned with respect to the catch lever for both operating the catch lever to start operation of the toast timer and being actuated by the catch lever at the end of a toasting cycle for moving the manually operable lever to open the main switch.

Abstract: A solid state electronic control system for a cooking oven is provided which is particularly adapted for cooking meat. The control system includes a first heat sensor which monitors the internal temperature of the oven, and it also includes a second heat sensor in the form of a probe which is inserted into the meat itself for monitoring the internal temperature of the meat. The control system can be set to different oven temperatures, and it operates automatically to maintain the oven to the selected temperature until the internal temperature of the meat reaches a particular level, as sensed by the probe. Then, the control system causes the oven temperature to drop gradually to a "hold" level as the meat is being cooked, and then to hold the oven temperature at the hold level until the meat is removed from the oven.

Abstract: The apparatus comprises a turntable carrying, in a circular array centered on a central rotational axis of the turntable, a plurality of vials extending below the underside of the turntable. A stepper motor imparts stepwise rotational motion to the turntable so that during dwell periods of the turntable, specimens in the vials can be investigated optically.Air in a space below the turntable and bounded laterally and at the bottom by an enclosure is circulated by a rotating vane, and a thermistor, responsive to the temperature in the region of the vials, controls a heater in the space below the turntable so as to maintain the temperature of the vials substantially at a predetermined value.

Abstract: A food cooking machine comprises a generally cylindrical vessel having liquid impervious walls, a closed end and an open end. A removable cap having a central axial vent opening closes the open end. The vessel is detachably supported on a base having a drive means engageable with the vessel for rotating the vessel about an axis substantially aligned with the vent opening and oriented between horizontal and an acute angle to horizontal and with the capped end of the vessel at least as elevated as the other end thereof. External heating means are provided for applying heat to the vessel contents through the vessel walls during rotation. The temperature in the vessel is selectively regulated by means of a temperature controller having a temperature sensing probe supported on the base in alignment with the vent opening in such manner that the opening is not blocked nor vessel rotation impeded.

Abstract: The apparatus comprises a turntable carrying, in a circular array centered on a central rotational axis of the turntable, a plurality of vials extending below the underside of the turntable. A stepper motor imparts stepwise rotational motion to the turntable so that during dwell periods of the turntable, specimens in the vials can be investigated optically.Air in a space below the turntable and bounded laterally and at the bottom by an enclosure is circulated by a rotating vane, and a thermistor, responsive to the temperature in the region of the vials, controls a heater in the space below the turntable so as to maintain the temperature of the vials at a predetermined value.

Abstract: A biscuit making oven comprises a fabricated chamber externally insulated and having bottom entry and exit openings for an endless conveyor arranged partly inside and outside of the oven. Inside the oven the conveyor has horizontal runs which carry the biscuits to be baked progressively down through the oven so that they encounter three stages of heating to perform different stages in the baking process. These stages of heating are independently controllable despite the absence of baffles in the oven. The oven has the advantage that it does not require to be constructed at site but can be factory fabricated and simply used at site.

Abstract: The disclosed invention describes an apparatus and method for bringing a system having high interactive portions to a predetermined temperature distribution. The invention includes a difference controller which provides, through two separate drivers, a fixed total amount of energy to the system being controlled. If the system being controlled also has a long cycle time, second and third temperature controllers may be used to bring the system to the equilibrium temperature with a minimum amount of overshoot. The invention is particularly advantageous when used in connection with a high pressure, high temperature vessel useful in growing quartz crystals.

Abstract: An electrically heated high temperature oven for removing organic contaminants from glassware and metals, wherein preset timers and a temperature controller direct a three-stage pyrolysis-oxidation process continually monitored by combustion detection systems and applied within a high temperature oven incorporating additional safety devices for a protection of personnel and equipment.

Abstract: The apparatus comprises a turntable carrying, in a circular array centered n a central rotational axis of the turntable, a plurality of vials extending below the underside of the turntable. A stepper motor imparts stepwise rotational motion to the turntable so that during dwell periods of the turntable, specimens in the vials can be investigated optically.Air in a space below the turntable and bounded laterally and at the bottom by an enclosure is circulated by a rotating vane, and a thermistor, responsive to the temperature in the region of the vials, controls a heater in the space below the turntable so as to maintain the temperature of the vials substantially at a predetermined value.

Abstract: The apparatus comprises a turntable carrying, in a circular array centered on a central rotational axis of the turntable, a plurality of vials extending below the underside of the turntable. A stepper motor imparts stepwise rotational motion to the turntable so that during dwell periods of the turntable, specimens in the vials can be investigated optically.Air in a space below the turntable and bounded laterally and at the bottom by an enclosure is circulated by a rotating vane, and a thermistor, responsive to the temperature in the region of the vials, controls a heater in the space below the turntable so as to maintain the temperature of the vials substantially at a predetermined value.