Method and apparatus for determining temperature of and controlling the evaporation of liquid samples

A method as claimed in any of the preceding claims wherein the sensor is sheathed in an impervious inert material so that it will not contaminate the sample or suffer corrosion.

A method as claimed in any of the preceding claims wherein the sensor is a thermocouple.

A method as claimed in any of the preceding claims wherein the sample holders are rotated at a speed of between 500-3000 rpm depending on g-force required and radius at which the samples are rotated.

Centrifugal evaporation apparatus comprising a vacuum chamber, a plurality of sample holders for containing separately contained liquid samples to be evaporated, which are located therein for rotation about a generally vertical axis, heating means for heating the sample holders and therefore the liquid samples therein, temperature sensitive probe means located in or adjacent at least one of the sample holders, signal path means for conveying electrical signals from the probe means to a signal processing means located within the chamber, a transmitting device also within the chamber for transmitting signals to a receiver outside the chamber, signals from the signal processing means being employed to modulate the transmitted signal so that when decoded by the remote receiver, the latter will provide a signal containing information about the temperature of the probe.

Methods for controlling the temperature of liquid samples in a centrifugal evaporator as described herein and with reference to and as illustrated in the accompanying drawings.

Apparatus for controlling the temperature of liquid samples in a centrifugal evaporator constructed and arranged to operate as described herein and with reference to and as illustrated in the accompanying drawings.

A method of determining the temperature of evaporating liquid samples containing or comprising at least one volatile component and contained in at least some of a plurality of individual sample holders which are mounted within a chamber and rotated during the evaporation process so that centrifugal force is exerted on volatile liquid contained therein, and wherein heat is supplied to the sample holders to heat the liquid therein whilst a pressure below atmospheric is maintained in the chamber in manner known per se, characterised in that a pressure sensing device is located in the chamber, sensing the pressure therein at least during the evaporation process, generating an electrical pressure data signal which is proportional to the sensed pressure, conveying along a signal path the pressure data signal to electronic data signal processing means which is programmed inter alia with information relating to the volatile component or components present in the samples, to convert the pressure data signal to a temperature value equal to that which equates to the measured vapour pressure for the known volatile component or components present.

A method of controlling the temperature to which the samples in a centrifugal evaporator are heated by heating means within a pressure chamber containing the samples, wherein the pressure within the chamber is determined by pressure sensing means, a data signal is generated proportional to the pressure, and energy to a heating means located within the chamber for heating the samples is controlled in response to the value of the pressure signal.

A method of supplying heat to liquid samples in a pressure vessel in a centrifugal evaporator, in which the samples are contained in a plurality of tubular containers which during centrifuging in the pressure vessel are swung from a generally vertical condition to a generally horizontal condition under the influence of increasing centrifugal forces, so that centrifugal forces are exerted on the liquid in the tubular containers as the pressure within the chamber is reduced, wherein radiant heat is directed towards the closed ends of the tubular containers whilst in their generally horizontal condition, thereby to achieve more uniform heating of the liquid samples.

A method of heating liquid samples contained in a centrifugal evaporator, wherein the samples are contained in a fixed regular array and more of the heat is directed to samples located in the central region of the array than is directed to samples around the periphery of the array.

Methods and apparatus as claimed in any of the preceding claims, wherein the heat source is a source of infra-red radiation.

Method or apparatus as claimed in any of the preceding claims, wherein the samples are contained in wells in a microtitre plate.

A method of heating as claimed in the preceding claims, wherein the samples are contained in an array of tubes, bottles or vials held in holders which uniformly swing upwardly from a vertical position to a generally horizontal position during rotation of a platform on which they are mounted.

A method of heating as claimed in any of the preceding claims, wherein the source of heating is situated at one radial position relative to the axis of rotation of the sample containers, and each sample is subjected to radiant heat energy as it passes the source of heat during its rotation around the said axis of rotation.

A method of heating as claimed in the preceding claims, wherein the source of heat extends around an arcuate path extending around some or all of the circular path of the samples.

A method of controlling the heating of liquid samples in a plurality of individual sample holders in a centrifugal evaporator wherein the samples are mounted for rotation within a vacuum chamber, the pressure of which is reduced during the evaporation process, wherein heating means is located in the chamber for heating the samples and control means is provided for controlling power to the heating means, and temperature signals from one or more probes, or a signal from a pressure sensor which detects the pressure within the chamber, are supplied to the heating control means which is programmed to provide a high heat input during early stages of the evaporation process, and smaller heat input during later stages of the process as the liquid within the samples is evaporated.

A method of controlling the heating of samples within a centrifugal evaporator wherein the samples are contained within a pressure vessel which is progressively evacuated by a vacuum pump so as to assist in the evaporation of the liquid from the samples wherein a vapour condenser is employed to increase the pumping speed to protect the vacuum pump from vapour emitted during the evaporation process, and wherein there is provided means for measuring vapour flow rate, and the method of control involves controlling the energy to the heater is controlled in response to a signal derived from the flow rate measurement such that as the flow rate decreases, the heating energy is decreased, and as the vapour flow rate approaches zero, indicating that the samples are all dry, the heat energy is shut off.

A method of supplying heat to a plurality of samples in each of a plurality of sample plates, each plate containing a plurality of wells or other liquid containing devices, each capable of containing one liquid sample, wherein the sample plates are supported on trays of a material having a high thermal conductivity, and the trays themselves are supported within, and have a good thermal path to and from, a support frame also formed from high thermal conductivity material, and heat is supplied to the support frame from which it is conducted by the thermal path to the trays and thereby to the samples plates and samples contained therein.

The method of heating a plurality of liquid samples as claimed in the preceding claim, wherein the heating is effected by infra-red radiation directed towards the said support frame.

Apparatus for supporting microtitre plates, each containing a plurality of liquid samples, for evaporation in a centrifugal evaporator, wherein heat is supplied to the microtitre plates via a supporting frame and via trays extending thereacross on which the microtitre plates are located, the trays and the frame being formed from a material having a high thermal conductivity, and wherein the region of each tray on which a microtitre plate is located, is formed with an upstanding region defining a platform adapted to fit into and engage a recessed underside of a microtitre plate located thereon, which would otherwise be spaced from the surface of the tray, thereby to improve the transfer of heat between the tray and the plate.

Apparatus as claimed in the preceding claim, wherein the frame and trays are formed from aluminium or copper.

Methods of controlling the heating of multiple samples in the pressure vessel of a centrifugal evaporator substantially as herein described and with reference to and as illustrated in the accompanying drawings.

Apparatus for controlling the heat to microtitre plates located within the vacuum chamber of a centrifugal evaporator constructed, arranged and adapted to operate substantially as herein described with reference to and as illustrated in the accompanying drawings.