EP3805671B1 - Absorption of combustible coolant - Google Patents

Description

The invention relates to the suppression of flammable and toxic gases in a device in which a left-handed refrigeration process takes place, for example a heat pump. In the meantime, flammable refrigerants are used in heat pumps and in cooling and freezing systems, which have the advantage of not damaging the climate or the ozone layer if they are accidentally released. However, due to their flammability, such an accidental release should be avoided as far as possible.

The Japanese disclosure document JP 2000 105034 A describes a refrigerator or freezer in which the refrigerated goods compartment is rendered inert by spraying in inert gas if an inflammable refrigerant escapes due to a leak. In addition, the door is opened so that no overpressure occurs. In addition, an adsorbent is installed in the floor area to bind escaping refrigerant.

This applies above all to the propane in the refrigerant R290, which is now frequently used, but also isobutane in the refrigerant R600a, n-butane in R600, propylene in R1270 and other alkanes and alkenes. Such lower-chain alkanes and alkenes can be absorbed and dissolved with poorly combustible substances with long carbon chains. If liquids are used for this that are classified as non-flammable or hardly flammable, these liquids can be sprayed and the lower-chain alkane or alkene is withdrawn from the air, and the mixture loses its flammability.

Suitable absorption liquids are long chain alcohols such as nonanol, decanol and undecanol, they are particularly suitable for absorbing propane.

The object of the invention is therefore to provide a method and a device to bind accidentally escaping working fluids so that they cannot ignite.

• auf ein auslösendes Signal hin eine unter hohem Druck befindliche schlecht brennbare oder unbrennbare Absorptionsflüssigkeit in das Gehäuse eingedüst wird,
• die Eindüsung solange aufrechterhalten wird, bis ein Signal zum Stoppen der Eindüsung erfolgt, und
• die ablaufende Absorptionsflüssigkeit aufgefangen wird.

The invention solves the problem by a corresponding method for the absorption of flammable working fluid in the housing of a device for operating a left-handed refrigeration circuit, wherein

• upon a triggering signal, a poorly flammable or non-flammable absorption liquid under high pressure is injected into the housing,
• the injection is maintained until a signal is given to stop the injection, and
• the draining absorption liquid is collected.

In configurations of the method it is provided that the absorption liquid is a long-chain carbon compound, preferably these are the liquids nonanol, decanol, undecanol or mixtures thereof.

In a further embodiment of the method, it is provided that the triggering signal follows a concentration measurement, with a triggering signal being given when 40 percent of the ignition limit of the concentration of the working fluid and air is reached. The stop signal is given when 10 percent or 5 percent of the corresponding ignition limit is reached. Trigger signal and stop signal can also occur several times in succession.

In a further embodiment it is provided that the absorbing liquid running off is collected in a separate container after being collected and fed to a reprocessing.

• einem Druckbehälter, der eine Absorptionsflüssigkeit enthält und der ein Treibgas enthalten kann,
• der Druckbehälter über eine Druckleitung mit einem automatischen Ventil verbunden ist,
• dieses Ventil mit einem Signalgeber verbunden ist, dessen Signale aus einer Konzentrationsmessung von gasförmigem Arbeitsfluid und einer Recheneinheit oder Analogelektronik zur Bestimmung der Zündgrenze entstammen,
• das Ventil mit einer Druckleitung verbunden ist, die zu mindestens einer Düse führt, die in dem Raum angeordnet ist, in welchem der linksdrehende Kältekreis durchgeführt wird,
• unterhalb des Raumes, in welchem der linksdrehende Kältekreis durchgeführt wird, eine Auffangwanne vorgesehen wird.

The invention also achieves the object by having a device for injecting absorption liquid into the housing of a device for operating a left-handed refrigeration circuit

• a pressure vessel containing an absorption liquid and which may contain a propellant gas,
• the pressure vessel is connected to an automatic valve via a pressure line,
• this valve is connected to a signal transmitter, the signals of which originate from a concentration measurement of gaseous working fluid and a computing unit or analogue electronics for determining the ignition limit,
• the valve is connected to a pressure line leading to at least one nozzle located in the space in which the left-hand refrigeration cycle is carried out,
• a drip tray is provided below the room in which the left-handed refrigeration cycle is carried out.

In one embodiment of the device, carbon dioxide or nitrogen is used as the propellant gas in the pressure vessel. This has the advantage that when the tank no longer contains any absorbent because it has been used up, the room is still rendered inert.

In a further embodiment of the device, the drip tray is provided with a vent which opens into a lockable and removable container. This has the advantage that the loaded absorption liquid can be removed and reprocessed.

Further configurations of the device relate to the injection. It is provided here that a very fine nozzle is used, which leads to a very fine mist during spraying. Multiple nozzles fed from a header can also be used. These nozzles can be aimed vertically or horizontally, and the aiming can be aimed at known risk points in the refrigeration circuit.

• Fig. 1: ein vereinfachtes Schema der Vorrichtung mit einer Düse,
• Fig. 2: ein vereinfachtes Schema der Vorrichtung mit vertikalen Düsen,
• Fig. 3: ein vereinfachtes Schema der Vorrichtung mit vertikalen und horizontalen Düsen.

The invention is explained in more detail below on the basis of three basic sketches using a heat pump. show here

• 1 : a simplified scheme of the device with a nozzle,
• 2 : a simplified scheme of the device with vertical nozzles,
• 3 : a simplified scheme of the device with vertical and horizontal nozzles.

1 shows a heat pump 1 with a refrigeration cycle 2 which is operated in a capsule housing 3 . A pressure vessel 4 is arranged above the capsule housing 3; the pressure vessel can also be arranged at any other, easily accessible location in the heat pump 1. The pressure vessel contains a mixture of nonanol, decanol and undecanol as the absorption liquid and carbon dioxide as the propellant.

The pressure tank 4 is connected to the automatic valve 5 via a pressure line. A concentration measurement for gaseous working fluid, which is R290 in this example, is used as the signal generator 6 for the valve 5 . The concentration is measured inside the capsule housing 3. As soon as a gas concentration of 40 percent of the ignition limit, which is 1.7 percent in air, ie 0.68 percent, is measured, the valve 5 opens automatically.

In this case, the absorption liquid is conducted via a pressure line to the atomizer nozzle 7, which is located inside the capsule housing 3, where fine atomization of the absorption liquid takes place. The absorption liquid dissolves the propane and drains into the drip tray 8. From there, it is channeled into the collection container 10 via a secured outlet. As soon as the concentration measurement falls below 10 percent of the ignition limit, i.e. 0.17 percent propane in air, the injection is stopped.

Should there be a leak in the refrigeration circuit, which should lead to a renewed increase in the propane concentration, this cycle can be repeated until the absorption liquid in the pressure vessel 4 is used up. The capsule housing is then rendered inert with the propellant gas, so that ignition is reliably prevented even if working fluid escapes further.

2 shows a heat pump 1 with the same structure as in FIG 1 , but with the difference that instead of a single nozzle, a horizontal row of nozzles 11 is provided in the head area of the capsule housing. As a result, the absorption liquid can be distributed more quickly in the capsule housing 3 . For this purpose, the pressure line behind the valve 5 is connected to a header 12, which distributes the absorption liquid evenly to all nozzles.

3 shows a heat pump 1 with the same structure as in FIG 2 , but with the difference that, in addition to a horizontal row of nozzles, vertical rows of nozzles 13 are also provided, which allow an even better distribution of the absorption liquid. Here, the nozzles can be directed at critical pipe connections or heat exchanger connections where leaks are possible.

reference list

1

heat pump

2

refrigeration cycle

3

capsule body

4

pressure vessel

5

Valve

6

Signal generator with concentration measurement

7

atomizer nozzle

8th

collection tray

9

process

10

collection container

11

horizontal row of nozzles

12

headers

13

vertical row of nozzles

Claims (11)

1. Method for absorbing flammable working fluid in the housing (1, 3) of a device for operating an anti-clockwise refrigeration cycle, characterised in that

   - in response to a triggering signal, a poorly combustible or incombustible absorption liquid under high pressure is injected into the housing (3),

   - injection is maintained until a signal is given to stop injection, and

   - the absorption liquid that runs off is collected.
2. Method according to claim 1, characterised in that the absorption liquid is a long-chain carbon compound.
3. Method according to claim 2, characterised in that the absorption liquid is selected from nonanol, decanol, undecanol or mixtures thereof.
4. Method according to any of claims 1 to 3, characterised in that the triggering signal follows a concentration measurement, wherein a triggering signal is given when 40 percent of the ignition limit of the working fluid/air concentration is reached.
5. Method according to any of claims 1 to 4, characterised in that the stop signal is given when 10 percent or 5 percent of the corresponding ignition limit is reached.
6. Method according to any of claims 1 to 5, characterised in that the absorption liquid that runs off is collected in a separate container after collection.
7. Device for injecting absorption liquid into the housing (3) of a device for operating an anti-clockwise refrigeration cycle, characterised by

   - a pressure vessel (4) which contains an absorption liquid and which may contain a propellant gas,

   - the pressure vessel (4) is connected to an automatic valve (5) via a pressure line,

   - this valve (5) is connected to a signal transmitter (6) whose signals originate from a concentration measurement of gaseous working fluid and a computer unit or analogue electronic system for determining the ignition limit,

   - the valve (5) is connected to a pressure line leading to at least one nozzle (7) arranged in the space of a capsule housing (3) in which the anti-clockwise refrigeration cycle is carried out,

   - wherein a collecting trough (8) is provided below the space of a capsule housing (3) in which the anti-clockwise refrigeration cycle is carried out.
8. Device according to claim 7, characterised in that carbon dioxide or nitrogen is used as the propellant gas in the pressure vessel (4).
9. Device according to any of claims 7 or 8, characterised in that the collection tray (8) is provided with a drain (9) which opens into a lockable and removable container (10).
10. Device according to any of claims 7 to 9, characterised in that a very fine nozzle (7) is used which results in very fine mist during spraying.
11. Device according to any of claims 7 to 10, characterised in that a plurality of nozzles (11, 13) are used which are fed via a header (12).

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