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EP-4741738-A1 - METHOD OF CONTROLLING TEMPERATURE IN AN ENCLOSURE, AND AIR CONDITIONING SYSTEM FOR AN ENCLOSURE

EP4741738A1EP 4741738 A1EP4741738 A1EP 4741738A1EP-4741738-A1

Abstract

A method of controlling temperature in an enclosure is provided. The method comprises: passing a refrigerant through a circuit of an air conditioning system, the circuit comprising in order: a condenser; a capillary; an evaporator; and a compressor. The air conditioning system further comprises: an evaporator airflow generator for blowing air over the evaporator; and an enclosure heater for heating the air to be blown over the evaporator by the evaporator airflow generator. The method further comprises: switching on the enclosure heater when ambient temperature outside of the enclosure falls below a threshold temperature.

Inventors

  • Josland, Graham
  • JOHNSON, NIGEL
  • HARROP, JOHN
  • Colloff, Paul

Assignees

  • Thermo Onix Ltd

Dates

Publication Date
20260513
Application Date
20241106

Claims (15)

  1. A method of controlling temperature in an enclosure, comprising: passing a refrigerant through a circuit of an air conditioning system, the circuit comprising in order: a condenser; a capillary; an evaporator; and a compressor, wherein the air conditioning system further comprises: an evaporator airflow generator for blowing air over the evaporator; and an enclosure heater for heating the air to be blown over the evaporator by the evaporator airflow generator; and switching on the enclosure heater when ambient temperature outside of the enclosure falls below a threshold temperature.
  2. The method of claim 1, wherein the air conditioning system further comprises a hot gas bypass valve configured to control a flow of refrigerant to pass directly from the compressor to the evaporator and bypass the condenser and capillary, and the method further comprises the step of: opening and closing the hot gas bypass valve in regular intervals.
  3. The method of claim 2, wherein the regular intervals are between 30 and 60 seconds.
  4. The method of any preceding claim, wherein the threshold temperature is 25° or less, preferably 20° or less.
  5. The method of any preceding claim, further comprising the step of purging the enclosure of gas.
  6. The method of any preceding claim, wherein the enclosure is an enclosure for a mass spectrometer, optionally for use in explosive atmosphere.
  7. An air conditioning system for an enclosure, comprising: a circuit for refrigerant, the circuit comprising in order: a condenser, a capillary; an evaporator; and a compressor; an evaporator airflow generator for blowing air over the evaporator; an enclosure heater for heating the air to be blown over the evaporator by the evaporator airflow generator; a controller configured to operate the enclosure heater in response to ambient temperature outside of the enclosure falling below a threshold temperature; and at least one sensor in communication with the controller, configured to monitor the air conditioning system.
  8. The air conditioning system of claim 7, further comprising a hot gas bypass valve configured to allow the refrigerant to pass directly from the compressor to the evaporator and bypass the condenser and capillary, wherein the controller is configured to open and close the hot gas bypass valve at regular intervals, optionally the regular intervals are between 30 and 60 seconds.
  9. The air conditioning system of any of claims 7 to 8, wherein the threshold temperature is 25° or less, preferably 20° or less.
  10. The air conditioning system of any of claims 7 to 9, further comprising a high-pressure switch configured to detect failures of the condenser, wherein the controller is configured to switch off the compressor in response to the high-pressure switch detecting a failure of the condenser.
  11. The air conditioning system of any of claims 7 to 10, further comprising a low-pressure switch configured to detect a loss of the refrigerant, wherein the controller is configured to switch off the compressor in response to the low-pressure switch detecting a loss of the refrigerant.
  12. The air conditioning system of any of claims 7 to 11, wherein the at least one sensor includes any of: an ambient temperature sensor; an enclosure temperature sensor; an evaporator airflow generator sensor; and/or an evaporator temperature sensor.
  13. The air conditioning system of any of claims 7 to 12, wherein the heater comprises: one or more cartridge heaters installed within a conductive block; and one or more heat sinks.
  14. The air conditioning system of any of claims 7 to 13, wherein one or more of the enclosure heater, compressor, and/or hot gas bypass valve, are controlled by solid state relays.
  15. The air conditioning system of any of claims 7 to 14, wherein the system is for a mass spectrometer, and comprises: a processor configured to control operation of the mass spectrometer, the processor in communication with the controller, optionally the mass spectrometer is for use in explosive atmosphere.

Description

Field The present specification relates to a method of controlling the temperature of an enclosure. Particularly, the enclosure may be an enclosure for a mass spectrometer. This could especially be a mass spectrometer for use in an explosive environment. An air conditioning system for a mass spectrometer is also described. Background Process Mass Spectrometers are typically installed in an enclosure (or shelter), and necessitate temperature regulation to ensure measurement stability and linearity. In order to keep the temperature stable, an air conditioning system is used to manage the temperature in the enclosure. This air conditioning unit serves to cool the instrument when situated in hot environments. However, it encounters challenges in maintaining temperature control under low temperature conditions. There is therefore a need for an improved method of controlling the temperature of an enclosure, and associated air conditioning system. US 3 113 439 A discloses a heat pump adapted to heat or cool air from an enclosure and more particularly to a control arrangement for a heat pump having outdoor temperature compensating means adapted to provide biasing of the heat pump control means in anticipation of the heating and cooling requirements of the enclosure. There is a biasing heater and a thermistor connected such that when the outdoor temperature decreases, the thermistor resistance increases and the heating output of the heater decreases. This addresses the problem of the temperature sensed by a sensor in the enclosure lagging the actual outdoor temperature by compensating with the biasing heater. Summary A method of controlling temperature in an enclosure is provided. The method comprising: passing a refrigerant through a circuit of an air conditioning system, the circuit comprising in order: a condenser; a capillary; an evaporator; and a compressor, wherein the air conditioning system further comprises: an evaporator airflow generator for blowing air over the evaporator; and an enclosure heater for heating the air to be blown over the evaporator by the evaporator airflow generator; and switching on the enclosure heater when ambient temperature outside of the enclosure falls below a threshold temperature. This allows for effective temperature maintenance, even during low temperature conditions. The evaporator airflow generator may specifically be an evaporator fan. This is a specific airflow generator which can be effective for this method. The air conditioning system may further comprise a hot gas bypass valve configured to control a flow of refrigerant to pass directly from the compressor to the evaporator and bypass the condenser and capillary, and the method may further comprise the step of: opening and closing the hot gas bypass valve in regular intervals. This can be used to raise the temperature in the enclosure when needed. The regular intervals may be between 30 and 60 seconds. Such regular intervals can effectively maintain a temperature in the enclosure. The threshold temperature may be 25° or less, preferably 20° or less. Below such a temperature, the additional heating of the enclosure heater can be useful to maintain the temperature in the enclosure. The method may further comprise the step of purging the enclosure of gas. This can allows the gas in the enclosure to be evacuated or removed. The enclosure may be an enclosure for a mass spectrometer, optionally for use in explosive atmosphere. Mass spectrometers may need their temperature regulated for repeatable results. In an explosive atmosphere it can be even more important and/or more difficult to regulate the temperature of the enclosure. An air conditioning system for an enclosure is provided. The air conditioning system comprising: a circuit for refrigerant, the circuit comprising in order: a condenser, a capillary; an evaporator; and a compressor; an evaporator airflow generator for blowing air over the evaporator; an enclosure heater for heating the air to be blown over the evaporator by the evaporator airflow generator; a controller configured to operate the enclosure heater in response to ambient temperature outside of the enclosure falling below a threshold temperature; and at least one sensor in communication with the controller, configured to monitor the air conditioning system. This air conditioning system allows for effective temperature maintenance, even during low temperature conditions. The evaporator airflow generator may specifically be an evaporator fan. This is a specific airflow generator which can be effective for this system. The air conditioning system may further comprise a hot gas bypass valve configured to allow the refrigerant to pass directly from the compressor to the evaporator and bypass the condenser and capillary, wherein the controller is configured to open and close the hot gas bypass valve at regular intervals. This can be used to raise the temperature in the enclosure when needed. The regular interva