Calorimetry

Claim 2

Microcalorimetry apparatus comprising structure defining a chamber, including structure defining a gas flow inlet passage connected to said chamber and a gas flow outlet passage connected to said chamber, a plurality of calorimeter units supported in said chamber in spaced relation to one another, each said calorimeter unit comprising structure of thermal insulation defining a compartment for receiving a sample container, thermally conductive structure in said compartment, said thermally conductive structure being configured to mate with the outer wall of said sample container so that said thermally conductive structure and said container are in thermal contact, means in contact with said thermally conductive structure for supplying heat to said compartment, a unit temperature sensor secured to said thermally conductive structure for providing an output signal as a function of the heat content of material in said compartment, terminal means for connecting said heat supply means and said temperature sensor to electrical circuitry external of said thermal insulation, and thermally insulated closure structure cooperative with said compartment defining structure for enclosing a sample container within said compartment, thermal insulation enclosing said chamber, means to continuously supply gas along a gas flow path from said gas flow inlet passage through said chamber to said gas flow outlet passage to maintain a positive pressure in said chamber sufficient to cause continuous flow of gas through said chamber and around said individual spaced calorimeter units, and means to stabilize the temperature of the gas continuously supplied to said chamber.

Claim 3

The apparatus as claimed in claim 1 and further including a reference temperature sensor in said chamber for providing a reference signal and electronic circuitry connected to said unit temperature sensor, said reference temperature sensor and said heat supply means for comparing said unit sensor output signal and said reference signal and controlling the application of heat to said thermally conductive structure of the calorimeter unit for equilibration of a sample disposed therein.

Claim 4

The apparatus as claimed in claim 1 wherein said chamber has a cover member and further including porous insulation in said cover member connected to said gas flow outlet passage.

Claim 5

The apparatus as claimed in claim 1 wherein said means to stabilize the temperature of said gas includes a plurality of heater stages disposed in series in said gas flow inlet passage, each said heater stage having an associated temperature sensor and circuitry responsive to its associated temperature sensor for controlling the heater stage.

Claim 6

The apparatus as claimed in claim 1 wherein said means to stabilize the temperature of said gas includes a temperature sensor disposed in said chamber and a heater stage responsive to said temperature sensor, said heater stage including a heater element and a bridge network, said sensor being connected in said bridge network, and said heater stage further including circuitry for applying an AC signal to said bridge network for modulating the error signal of the bridge network and synchronous demodulation circuitry connected between said bridge network and said heater element for controlling the energization of said heater element.

Claim 7

The apparatus as claimed in claim 1 wherein said means to stabilize the temperature of said gas includes a series of heater stages in said gas flow inlet passage and the gas is exhausted from said chamber through said gas flow outlet passage into an electronics compartment housing electronic control circuitry for stabilizing the thermal environment in said electronics compartment.

Claim 8

The apparatus as claimed in claim 1 and further including fan means and a series of heater stages disposed in said gas flow inlet passage, each said heater stage having an associated temperature snesor, the sensor associated with the final heater stage being disposed in said chamber, and electronic circuitry responsive to each sensor for controlling the associated heater element, said electronic circuitry being disposed in an electronics compartment and said gas, after being exhausted from said chamber through said gas flow outlet passage, flows into said electronics compartment for stabilizing the thermal environment in said electronics compartment.

Claim 9

The apparatus as claimed in claim 7 and further including a reference sensor in said chamber connected to provide a reference signal for equiliBration of the samples in said calorimeter unit.

Claim 10

Microcalorimetry apparatus comprising structure defining a chamber, a calorimeter unit in said chamber, said calorimeter unit comprising structure of thermally conductive material defining a compartment for receiving a sample container, the inner wall of said thermally conductive structure being configured to mate with the outer wall of said sample container so that said inner and outer walls are in thermal contact, thermal insulation surrounding said thermally conductive structure, heater means in contact with said thermally conductive structure for aupplying heat to said compartment, a temperature sensor secured to said thermally conductive structure for providing an output signal as a function of the heat content of material in said compartment, terminal means for connecting said heater means and said temperature sensor to electrical circuitry external of said thermal insulation, and thermally insulated closure structure cooperative with said thermally conductive structure for enclosing a sample container within said compartment, thermal insulation enclosing said chamber, means to supply gas to said chamber along a gas flow path and means to stabilize the temperature of the gas supplied to said chamber, said means to stabilize the temperature of said gas including a temperature sensor and a heater stage responsive to said temperature sensor, said heater stage including a bridge network in which said temperature sensor is connected, zero crossing circuitry, ramp generator circuitry connected to said bridge network for modulating the output of said bridge network, amplifier circuitry responsive to the outputs of said bridge network and said zero crossing circuitry, and a heater element responsive to the output of said amplifier circuitry disposed in said gas flow path.

Claim 11

Microcalorimetry apparatus comprising structure defining a chamber, a calorimeter unit in said chamber, said calorimeter unit comprising structure of thermally conductive material defining a compartment for receiving a sample container, the inner wall of said thermally conductive structure being configured to mate with the outer wall of said sample container so that said inner and outer walls are in thermal contact, thermal insulation surrounding said thermally conductive structure, heater means in contact with said thermally conductive structure for aupplying heat to said compartment, a temperature sensor secured to said thermally conductive structure for providing an output signal as a function of the heat content of material in said compartment, terminal means for connecting said heater means and said temperature sensor to electrical circuitry external of said thermal insulation, and thermally insulated closure structure cooperative with said thermally conductive structure for enclosing a sample container within said compartment, thermal insulation enclosing said chamber, means to supply gas to said chamber along a gas flow path and means to stabilize the temperature of the gas supplied to said chamber, said means to stabilize the temperature of said gas including a temperature sensor and a heater stage responsive to said temperature sensor, said heater stage including a bridge network in which said temperature sensor is connected, zero crossing circuitry, ramp generator circuitry connected to said bridge network for modulating the output of said bridge network, amplifier circuitry responsive to the outputs of said bridge network and said zero crossing circuitry, and a heater element responsive to the output of said amplifier circuitry disposed in said gas flow path.

Claim 12

Microcalorimetry apparatus comprising structure defining a chamber, including structure defining a gas flow inlet passage connected to said chamber and a gas flow outlet passage connected to said chamber, a plurality of calorimeter units supported in said chamber in spaced relation to one another, each said calorimeter unit including structure of thermal insulation defining a compartment for receiving a sample container, thermally conductive structure in said compartment, said thermally conductive structure being configured to mate with the outer wall of said sample container so that said thermally conductive structure and said container are in thermal contact, means in contact with said thermally conductive structure for supplying heat to said compartment, a calorimeter unit temperature sensor secured to said thermally conductive structure for providing an output signal as a function of the heat content of material in said compartment, means for connecting said heat supply means and said temperature sensor to electrical circuitry external of said thermal insulation, and thermally insulated closure structure cooperative with said compartment defining structure for enclosing a sample container within said compartment, thermal insulation enclosing said chamber, means to continuously supply gas along a gas flow path from said gas flow inlet passage through said chamber to said gas flow outlet passage to maintain a positive pressure in said chamber sufficient to cause continuous flow of gas through said chamber and around said individual spaced calorimeter units, means to stabilize the temperature of the gas continuously supplied to said chamber, a reference sensor in said chamber connected to provide a reference signal, and comparison circuitry responsive to said reference signal and the output signal of a calorimeter unit temperature sensor for equilibration of a sample in said calorimeter unit.

Claim 13

Microcalorimetry apparatus comprising structure defining a chamber, including structure defining a gas flow inlet passage connected to said chamber and a gas flow outlet passage connected to said chamber, a plurality of calorimeter units supported in said chamber in spaced relation to one another, each said calorimeter unit including structure of thermal insulation defining a compartment for receiving a sample container, thermally conductive structure in said compartment, said thermally conductive structure being configured to mate with the outer wall of said sample container so that said thermally conductive structure and said container are in thermal contact, means in contact with said thermally conductive structure for supplying heat to said compartment, a calorimeter unit temperature sensor secured to said thermally conductive structure for providing an output signal as a function of the heat content of material in said compartment, means for connecting said heat supply means and said temperature sensor to electrical circuitry external of said thermal insulation, and thermally insulated closure structure cooperative with said compartment defining structure for enclosing a sample container within said compartment, thermal insulation enclosing said chamber, means to continuously supply gas along a gas flow path from said gas flow inlet passage through said chamber to said gas flow outlet passage to maintain a positive pressure in said chamber sufficient to cause continuous flow of gas through said chamber and around said individual spaced calorimeter units, means to stabilize the temperature of the gas continuously supplied to said chamber, a reference sensor in said chamber connected to provide a reference signal, and comparison circuitry responsive to said reference signal and the output signal of a calorimeter unit temperature sensor for equilibration of a sample in said calorimeter unit.

Claim 16

The method as claimed in claim 11 wherein said positive derivative step includes sensing the difference between the heat produced during successive intervals of time.

Claim 17

Apparatus for use in detecting bacterial growth comprising structure defining a chamber, including structure defining a gas flow inlet passage connected to said chamber and a gas flow outlet passage connected to said chamber, a plurality of calorimeter units supported in said chamber in spaced relation to one another, each said calorimeter unit comprising structure of thermal insulation defining a compartment for receiving a sample container, thermally conductive structure in said compartment, said thermally conductive structure being configured to mate with the outer wall of said sample container so that said thermally conductive structure and the outer wall of said container are in thermal contact, means in contact with said thermally conductive structure for supplying heat to said compartment, a calorimeter unit temperature sensor secured to said thermally conductive structure for providing an output signal as a function of the heat content of material in said compartment, means for connecting said heat supply means to electrical circuitry external of said thermal insulation, and means to connect detector means to said temperature sensor for detecting heat production by a sample in said calorimeter unit, means to continuously supply gas along a gas flow path from said gas flow inlet passage through said chamber to said gas flow outlet passage to maintain a positive pressure in said chamber sufficient to cause continuous flow of gas through said chamber and around said individual spaced calorimeter units, and means to stabilize the temperature of the gas continuously supplied to said chamber.

Claim 18

Apparatus for use in detecting bacterial growth comprising structure defining a chamber, including structure defining a gas flow inlet passage connected to said chamber and a gas flow outlet passage connected to said chamber, a plurality of calorimeter units supported in said chamber in spaced relation to one another, each said calorimeter unit comprising structure of thermal insulation defining a compartment for receiving a sample container, thermally conductive structure in said compartment, said thermally conductive structure being configured to mate with the outer wall of said sample container so that said thermally conductive structure and the outer wall of said container are in thermal contact, means in contact with said thermally conductive structure for supplying heat to said compartment, a calorimeter unit temperature sensor secured to said thermally conductive structure for providing an output signal as a function of the heat content of material in said compartment, means for connecting said heat supply means to electrical circuitry external of said thermal insulation, and means to connect detector means to said temperature sensor for detecting heat production by a sample in said calorimeter unit, means to continuously supply gas along a gas flow path from said gas flow inlet passage through said chamber to said gas flow outlet passage to maintain a positive pressure in said chamber sufficient to cause continuous flow of gas through said chamber and around said individual spaced calorimeter units, and means to stabilize the temperature of the gas continuously supplied to said chamber.

Claim 19

The apparatus as claimed in claim 13 and further including a reference temperature sensor in said chamber for providing a reference signal and electronic circuitry connected to a calorimeter unit temperature sensor, said reference temperature sensor and said heat supplying means for comparing said unit sensor output signal and said reference signal and controlling the application of heat to said thermally conductive structure of the calorimeter unit for equilibration of a sample disposed therein.

Claim 20

The apparatus as claimed in claim 13 and further including and a gas flow outlet passage connected to said chamber, thermal insulation enclosing said chamber, at least a portion of said thermal insulation being porous, and wherein said means to supply gas along a gas flow path to said chamber to maintain a positive pressure in said chamber causes continuous flow of gas through said porous insulation and.

Claim 21

The apparatus as claimed in claim 15 and further including a reference temperature sensor in said chamber for providing a reference signal and electronic circuitry connected to a calorimeter unit temperature sensor, said reference temperature sensor and said heat supplying means for comparing said unit sensor output signal and said reference signal and controlling the application of heat to said thermally conductive structure of the calorimeter unit for equilibration of a sample disposed therein.

Claim 22

The apparatus as claimed in claim 16 and further including electronic circuitry responsive to each said sensor, the electronic circuitry coupled to said reference sensor providing said reference signal and the electronic circuitries coupled to the others of said sensors each including a summing junction to which said reference signal is applied to control operation of the associated calorimeter unit heater means.

Claim 23

The apparatus as claimed in claim 17 and further including fan means and a series of heater stages disposed in said gas flow path, each said heater stage having an associated temperature sensor, the sensor associated with the final heater stage being disposed in said chamber, and electronic circuitry responSive to each sensor for controlling the associated heater element, said electronic circuitry being disposed in an electronics compartment and said gas, after being exhausted from said chamber through said porous insulation, flows into said electronics compartment and is exhausted from said compartment to the atmosphere.