Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B32/00—Carbon; Compounds thereof
  • C01B32/50—Carbon dioxide
  • C01B32/55—Solidifying

Definitions

• the invention relates to a device for generating and storing carbon dioxide snow, with a container into which a snow horn connected to a supply line for liquid carbon dioxide and a gas discharge line opens, and with a measuring device for detecting the level of carbon dioxide snow in the container.
• So-called snow horns are usually used to produce carbon dioxide snow.
• liquid carbon dioxide brought in via a pressure line is released at an expansion nozzle, whereupon the liquid carbon dioxide changes into a mixture of carbon dioxide gas and carbon dioxide snow.
• the expansion nozzle is usually arranged at the tip of a conically widening mouth funnel, through which a certain directional guidance of the snow-gas mixture produced is ensured.
• the expansion nozzle for liquid carbon dioxide can also be mounted in a container.
• DE 2017008488 A1 or EP 3 222946 A1 describes a device for metering carbon dioxide snow in which an expansion nozzle for liquid carbon dioxide opens inside a container.
• the container is also equipped with a gas discharge line that leads away from the container above the expansion nozzle. When the liquid carbon dioxide is released, the resulting carbon dioxide snow sinks towards the bottom of the container, while the resulting carbon dioxide gas is drawn off via the gas discharge line.
• EP 3222946 A1 also has a device by means of which a predetermined amount of carbon dioxide snow can be withdrawn from the container from time to time and fed for further use, for example for cooling product surfaces or for filling a refrigerant compartment of a cooling container.
• a device by means of which a predetermined amount of carbon dioxide snow can be withdrawn from the container from time to time and fed for further use, for example for cooling product surfaces or for filling a refrigerant compartment of a cooling container.
• the reaching of a certain minimum filling level is determined by means of a sensor - not specified in detail in this publication.
• the filling level of carbon dioxide snow in a container is currently mostly determined with a temperature sensor.
• the container As soon as the increasing amount of carbon dioxide snow in the container has reached the sensor, it indicates a constant temperature of, for example (at ambient pressure) -78.5 ° C, and the container can be regarded as filled at least up to the height of the sensor.
• the container can be regarded as filled at least up to the height of the sensor.
• the invention is therefore based on the object of creating a device for generating and storing carbon dioxide snow, in which the carbon dioxide snow filling level in the interior of the container can be determined with greater reliability.
• the measuring device comprises a photoelectric sensor unit which is arranged vertically spaced from the bottom of the container and has a light emitting transmitter and a light-sensitive receiver.
• the transmitter and receiver of the photoelectric sensor unit can be accommodated in the same housing, but this is not absolutely necessary within the scope of the invention.
• the transmitter emits light in the direction of the inside of the container.
• the frequency of the light is irrelevant as long as it is guaranteed that the light is at least partially reflected on dry ice particles.
• Light in the optical or infrared range is particularly suitable. If the light hits a large number of dry ice particles inside the container, as occurs in particular during snowmaking, a diffuse reflection occurs and some of the light reaches the receiver.
• the container fills with carbon dioxide snow. If the filling level of carbon dioxide snow exceeds the vertical position of the transmitter in the container, the receiver can no longer receive any or almost no signal from the transmitter. There is therefore a strong change in the signal registered at the receiver. If the snow level continues to rise, the signal hardly changes and thus shows an operator that there is a minimum fill level in the container. If several sensor units are arranged vertically one above the other, the filling level in the container can be determined with greater precision in this way.
• the heat radiated by the sensor unit is usually sufficient to form an air cushion in front of the sensor unit, which prevents the permanent accumulation of carbon dioxide snow and thus ensures the functionality of the sensor unit.
• An additional heating device for heating the sensor unit is usually not required. The provision of such a heating device can nevertheless be advantageous, in particular when the humidity in the atmosphere inside the container is too high, in order to eliminate or prevent deposits of carbon dioxide snow or water ice in the area of the sensor unit.
• the measurement result of the photoelectric sensor unit is not or only insignificantly influenced by such a heating device.
• the transmitter and receiver of the photoelectric sensor unit are preferably to be mounted in a side wall of the container in such a way that their front surface is aligned with the inner wall of the container.
• the front surface can be an integral part of the transmitter or receiver, such as an LED or a photodiode, which are usually insensitive to the temperatures of approx. -78.5 ° C within the container.
• the transmitter and receiver can also be arranged behind a wall made of a transparent material, such as glass, which separates the sensor unit from the container interior and which in turn is arranged in alignment with an inner wall of the container.
• a wall made of a transparent material such as glass
• the invention is not limited to such a configuration, but the photoelectric sensor unit can also be placed at other locations.
• transmitters and / or receivers can be mounted within a channel in the wall of the container, with the respective front surfaces set back from the inner surface of the container in order to protect the components.
• a plurality of photoelectric sensor units are arranged vertically one above the other and at a distance from one another.
• a particularly preferred embodiment of the invention provides that the device has a removal device for removing carbon dioxide snow from the container.
• a removal device for removing carbon dioxide snow from the container.
• This is equipped with means that allow the removal of a predetermined amount of carbon dioxide snow from the container at regular time intervals.
• These means are, for example, a separating device which separates a section of the container filled with carbon dioxide snow from the rest of the container at regular time intervals and which cooperates with a thrust element which, after separation, pushes out the carbon dioxide snow located in this section of the container.
• a removal device is described, for example, in EP 3222946 A1.
• the means can also be, for example, a rotary valve.
• the removal device is preferably designed in such a way that a predetermined amount is obtained in rapid succession, for example at time intervals between 1s and 30s Carbon dioxide snow can be discharged or expelled from the container.
• the determination of the filling level according to the invention signals that there is a sufficient amount of carbon dioxide snow in the container for regular removal.
• the photoelectric sensor unit is preferably in data connection with a control unit, by means of which the inflow of liquid carbon dioxide in the supply line and / or the extraction of carbon dioxide from the container at the extraction device can be regulated as a function of a detected level of carbon dioxide snow in the container. In this way, the supply of liquid carbon dioxide and / or the removal of carbon dioxide snow from the container can be automatically controlled with great reliability according to a predetermined program and thus carried out with high efficiency.
• FIG. 1 shows schematically a device according to the invention in longitudinal section.
• the device 1 shown in FIG. 1 comprises a thermally well-insulated container 2 in the form of an upright cylinder with, for example, a rectangular cross-section, in whose - geodetically speaking - upper end face a snow horn 3 and a gas discharge line 4 open.
• the snow horn 3 is connected to a feed line 5 for liquid carbon dioxide, which in turn is connected to a tank, not shown here, in which the carbon dioxide is stored at a pressure of, for example, 15 bar.
• the snow horn 3 comprises a relaxation nozzle 6, which at the same time forms the end of the supply line 5, and a diffuser 7 protruding into the interior of the container 2.
• a removal device 8, not explained in detail here, for removing carbon dioxide snow is arranged at the bottom of the container 2.
• this is a removal device that allows the removal of predetermined amounts of carbon dioxide snow at regular time intervals, as described, for example, in EP 3222946 A1 or WO 2017/167620 A1, to which reference is expressly made here.
• the removal device 8 is designed so that in its operation at the same time intervals of between 1s and 30s, for example every 5s to 10s, an equal amount of carbon dioxide snow is expelled from the container 2 in each case.
• a photoelectric sensor unit 10 is arranged in a side wall of the container 2 at a vertical distance from the bottom of the container 2.
• the photoelectric sensor unit 10 comprises a transmitter 11 and a receiver 12, which in the exemplary embodiment are accommodated in a common housing 9.
• the transmitter 11 is able to emit light of a specific frequency or a specific frequency range, for example a frequency or a frequency range in the optical or infrared spectrum.
• the receiver is able to detect light of the same frequency or the same frequency range and convert it into an electronic signal.
• the transmitter 11 and receiver 12 are in data connection with a control unit 13, from which the emission of light at the transmitter 11 is initiated and in which electronic data from the receiver 12 can be processed.
• the control unit 13 is also in data connection with the extraction device 8 and with a valve 14 in the feed line 5, by means of which the inflow of liquid carbon dioxide through the feed line 5 is regulated according to a control command transmitted by the control unit 13 and, for example, to the per time unit from the container 2 the amount of carbon dioxide snow to be taken can be adjusted.
• the sensor unit 10 is installed in the wall of the container 2 in such a way that the transmitter
• the front surfaces 15, 16 can be part of the respective electronic module, that is to say transmitter 11 or receiver
• the container As long as the filling level of the carbon dioxide snow collecting in the container 2 has not yet reached the level of the sensor unit 10, for example the container is only filled to a first filling level 19, there is a turbulent flowing mixture at the level of the sensor unit 10 while the carbon dioxide is being supplied from carbon dioxide snow and carbon dioxide gas. Light that is emitted from the transmitter 11 into the interior of the container 2 is diffusely reflected by this mixture and a small part is collected by the receiver 12. The receiver 12 sends a corresponding signal to the control unit 13, which signals this that the filling level of the snow has not yet reached the level of the sensor unit 10. However, if the filling level of the carbon dioxide snow in the container 2 exceeds the level of the sensor unit 10, i.e.
• the light emitted by the transmitter 11 is no longer able to penetrate the layer of snow immediately in front of the transmitter 11 and no, or not very little of it to the receiver 12.
• the receiver 12 sends a corresponding electronic signal to the control unit 13, which prompts the control unit 13 to issue further control commands, for example to close or throttle the valve 14 in the supply line 5, according to a predetermined program, for example and / or for actuating the extraction device 8 for the extraction of carbon dioxide.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Inorganic Chemistry (AREA)
• Carbon And Carbon Compounds (AREA)
• Investigating Or Analysing Materials By Optical Means (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=75108335

Family Applications (1)

Country Status (6)

Family Cites Families (13)

• 2020
  • 2020-04-08 DE DE102020002206.5A patent/DE102020002206A1/de active Pending
• 2021
  • 2021-03-17 CN CN202180024500.7A patent/CN115485238B/zh active Active
  • 2021-03-17 WO PCT/EP2021/056874 patent/WO2021204509A1/de unknown
  • 2021-03-17 US US17/907,427 patent/US20230124187A1/en active Pending
  • 2021-03-17 BR BR112022020220A patent/BR112022020220A2/pt unknown
  • 2021-03-17 EP EP21713002.0A patent/EP4132881A1/de not_active Withdrawn

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