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Title:
METHOD FOR FIRE- AND EXPLOSIVE SAFE CHARGING OF A REFRIGERANT
Document Type and Number:
WIPO Patent Application WO/2018/185271
Kind Code:
A1
Abstract:
Method for fire- and explosive safe charging of a refrigerant to refrigerators, air conditioning units, cooling or heating circuits etc., where the method comprises at least the following steps: • Connecting a charging adapter to a unit to be charged by means of a quick-connector, • Checking proper connection of charging adapter · Monitoring gas presence and ventilation inside the charging system, • Pressure check of RAC system. • Leak-checking of RAC system. • Receiving signals for operation permission from a safety emergency relay, · Supply of refrigerant from e.g. a bottle situated in a supply cabinet to a charging station and the charging adapter, • Charging the unit to be charged, • Evacuation of gas from the quick-connector, • Leak-checking quick-connector · Disconnecting the charging adapter from the charged unit by disconnecting the quick-connector, • Stopping the mentioned functions. whereby, a safe operation during a production line charging of air conditioners/refrigerators is assured.

Inventors:
THYSSEN, Leif (Trompeterager 14, 6470 Hørup, 6470, DK)
BENTZON, Jens Christian (Skovbrynet 47, 6400 Sønderborg, 6400, DK)
CORDING, Loius Bernhard (Lassensvej 5, 6300 Graasten, 6300, DK)
KLIETSCH, Morten (Grundtvigsparken 84, 6400 Sønderborg, 6400, DK)
Application Number:
EP2018/058830
Publication Date:
October 11, 2018
Filing Date:
April 06, 2018
Export Citation:
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Assignee:
AGRAMKOW FLUID SYSTEMS A/S (Augustenborg Landevej 19, 6400 Sønderborg, 6400, DK)
International Classes:
F25B45/00; F25B49/00
Foreign References:
US20120247131A12012-10-04
US3208232A1965-09-28
US20130086934A12013-04-11
US20080022701A12008-01-31
US20090188263A12009-07-30
US20160123642A12016-05-05
US20080190208A12008-08-14
Other References:
None
Attorney, Agent or Firm:
ZACCO DENMARK A/S (Arne Jacobsens Allé 15, 2300 København S, 2300, DK)
Download PDF:
Claims:
CLAIMS

1 . Method for fire- and explosive safe charging of a refrigerant to refrigerators, air conditioning units, cooling or heating circuits etc., characterized in that the method comprises at least the following steps:

• Connecting a charging adapter to a unit to be charged by means of a quick-connector,

• Checking proper connection of charging adapter

• Monitoring gas presence and ventilation inside the charging system, · Pressure check of RAC system.

• Leak-checking of RAC system.

• Receiving signals for operation permission from a safety emergency relay,

• Supply of refrigerant from e.g. a bottle situated in a supply cabinet to a charging station and the charging adapter,

• Charging the unit to be charged,

• Evacuation of gas from the quick-connector,

• Leak-checking quick-connector

• Disconnecting the charging adapter from the charged unit by discon- necting the quick-connector,

• Stopping the mentioned functions.

2. Method for fire- and explosive safe charging of a refrigerant according to claim 1 , characterized in that connecting an adapter to a unit to be charged comprises two different concepts:

• below 150 gram refrigerant charge of the adapter, where the adaption to the unit to be charged is done via a tube-adapting quick-connector, and • above 150 gram refrigerant charge of the adapter, where the adaption to the unit to be charged is done via a threaded connecting quick-connector. 3. Method for fire- and explosive safe charging of a refrigerant according to claim 2, characterized in that, the tube-adapters, for the below 150 gram refrigerant charge, are divided into two different types:

• type I: where metallic claws are used to grip onto the tube, and,

• type II, where a gasket gripping is used.

4. Method for fire- and explosive safe charging of a refrigerant according to any of claims 1 to 3, characterized in that monitoring of gas inside the charging system is conducted by means of a gas sensor, and monitoring ventilation inside the charging system is conducted by a dP sensor or a flow sensor.

5. Method for fire- and explosive safe charging of a refrigerant according to any of claims 1 to 4, characterized in that the monitoring of gas inside the charging system is conducted by means of a gas sensor, defining at least two alarm levels, 10 % LEL and 25 % LEL.

6. Method for fire- and explosive safe charging of a refrigerant according to any of claims 1 to 5, characterized in that the signals for operation permission comprise at least signals from the following:

• Activated purge flow switches,

· non-activated gas alarms,

• non-activated emergency stop/ overall emergency stop.

7. Method for fire- and explosive safe charging of a refrigerant according to any of claims 1 to 6, characterized in that supply of refrigerants to the charg- ing station comprises at least the following step, where the charging station is supplied by a supply pump, drawing the refrigerant from e.g. bottles situated in a bottle cabinet.

8. Method for fire- and explosive safe charging of a refrigerant according to any of claims 1 to 7, characterized in that supply of refrigerants to the charging station comprises at least the following step, where the refrigerant supply is conducted by e.g. a bottle supply, connected to one bottle at a time.

9. Method for fire- and explosive safe charging of a refrigerant according to any of claims 1 to 8, characterized in that charging the adapter implies a mechanical interlock.

10. Method for fire- and explosive safe charging of a refrigerant according to any of claims 1 to 9, characterized in that evacuation is conducted by a vac- uum device leading the gas to the outside via a ventilation system.

1 1 . Method for fire- and explosive safe charging of a refrigerant according to any of claims 1 to 10, characterized in that the method after stopping all functions comprises at least the following steps: closing at least one safety valve, turning off all power and disconnecting all refrigerant supplies.

12. Method for fire- and explosive safe charging of a refrigerant according to any of claims 1 to 1 1 , characterized in that stopping the functions comprises at least the following: an ordinary process stop button, a control off switch and an emergency stop button.

13. Apparatus for a fire- and explosive safe charging of a refrigerant, characterized in that the apparatus is configured for a method according to claim 1 to 12 comprises at least: a charging station comprising at least one charging adapter and a ventilation inlet, where the charging station is connected to e.g. a bottle supply cabinet with a ventilation outlet.

14. Apparatus for a fire- and explosive safe charging of a refrigerant according to claim 13, characterized in that the apparatus further comprises a supply pump at least in one of the following places: the charging station, the bottle supply cabinet, a separate unit between the bottle supply cabinet and the charging station.

15. Apparatus for a fire- and explosive safe charging of a refrigerant according to any of claims 13 to 14, characterized in that the apparatus comprises a safety emergency relay connected to at least one of the following: a gas sensor, an alarm lamp tower, a dP-sensor, a flow sensor or an emergency stop.

Description:
Method for fire- and explosive safe charging of a refrigerant Field of the Invention

The present invention relates to a method for fire- and explosive safe charging of a refrigerant to refrigerators, air conditioning units, cooling or heating circuits etc., as well as to an apparatus for a fire- and explosive safe charging of a refrigerant.

Background of the Invention

It is known to fill flammable refrigerants into units for air conditioning or for fridges/refrigerators at production lines where the units on e.g. a conveyor en- ter a charging area, where a trough tray or a hole is formed below the conveyor, where the filling takes place. The trough tray or hole is connected to a ventilation system connected to the outdoors; so that the charging area is always well ventilated in order to prevent that gas leaks will ever reach a dangerous level. A gas sensor is, therefore, also installed in the trough or hole, from where the gas sensor is connected to and a gas alarm system. As flammable refrigerants are heavier than air, this method requires a ventilation system with a large capacity to fulfil the safety requirement and with the large change in ventilation, a lot of heat is also lost to the environment.

Object of the Invention

It is an object of the invention to assure safe operation during a production line charging of air conditioners/refrigerators, where any hazardous zone in the surrounding of the production line equipment is avoided - and where a no zone at the surrounding of the charging adapter is present. Thus, an uncontrolled release of refrigerants to the environment is eliminated. Description of the Invention

The definition of a no zone is a non-hazardous zone or a fire- and explosive safe charging zone, where no ventilation is required at the charging adapter, hence, a fire- and explosive safe charging is present.

The definition of a zone 2 is a zone where an exceptional and only short escape of a gas within a defined area. In this case, the Zone 2 area is of ø 0,5 metre from the charging adapter can occur, and no ventilation is required at the charging adapter.

Thus, for the present invention the definition of a zone 2 is ø 0,5 metre from the charging adapter. However, for other methods and apparatus, a zone 2 could be larger than 0,5 metre.

According to a first aspect of the invention, the above object is achieved with a method for fire- and explosive safe charging of a refrigerant to refrigerators, air conditioning units, cooling or heating circuits etc., where the method comprises at least the following steps:

• Connecting a charging adapter to a unit to be charged by means of a quick-connector,

• Checking proper connection of charging adapter

• Monitoring gas presence and ventilation inside the charging system,

• Pressure check of RAC system.

• Leak-checking of RAC system.

• Receiving signals for operation permission from a safety emergency relay,

• Supply of refrigerant from e.g. a bottle situated in a supply cabinet to a charging station and the charging adapter,

• Charging the unit to be charged,

• Evacuation of gas from the quick-connector,

• Leak-checking quick-connector • Disconnecting the charging adapter from the charged unit by disconnecting the quick-connector,

• Stopping the mentioned functions. This makes it possible to assure safe operation during a production line charging of airconditioners/refrigerators, (called RAC systems), using flammable refrigerants such as R600a and R290. Basically, it is all about avoiding having a hazardous zone in the surroundings of the production line equipment - and a reduced - or even no zone in the surroundings of the charging adapter.

The method and apparatus claimed and described has been designed according to ATEX 2014/34/EC and 1999/92/EC directives and reviewed accordingly by TL)V to assure the approval of local authorities. In a second aspect, the present invention also relates to a method for fire- and explosive safe charging of a refrigerant, where connecting an adapter to a unit to be charged comprises two different concepts:

• below 150 gram refrigerant charge of the product, where the adaption to the unit to be charged is done via a tube-adapting quick-connector, and

• above 150 gram refrigerant charge of the adapter, the adaption to the unit to be charged is done via a threaded connecting quick-connector.

This makes it possible to categorize the adaption in 2 different concepts: below 150 gram, where the adaption to the appliance can be done via a tube- adapter/quick-connector and above 150 gram, where the adaption must be done via a threaded connection/quick-connector.

When using threaded connection to the charged unit, the risk of major leaks from this connection is practically eliminated. When the charging is finished, the space between the charging adapter and quick-connector is drained. In case the valve in the quick-connector is leaky, the pressure in the vacuum system will rise considerably and the system is reopened and drained completely. Therefore, will there be no risk of a release into the surroundings, after disconnection of the adapter. After completed leak test of the quick-coupler, the adapter is disconnected. The coupling is evacuated prior to disconnection, (or drained completely), wherefore nothing is released into the surroundings of the operator. The purge from the vacuum device, being e.g. a vacuum system, a vacuum pump or an ejector, and the safety valve is connected directly to the ventilation system. The amount in the charging adapter evacuated by the vacuum device is as low as for example only 0,13 gram. The zone of the appliance to be charged follows the definition of the zone of the charging adapter.

In a third aspect, the present invention also relates to a method for fire- and explosive safe charging of a refrigerant, where the tube-adapters, for the below 150 gram refrigerant charge are divided into two different types:

• type I: where metallic claws are used to grip onto the tube, and,

• type II, where a gasket gripping is used.

This makes it possible to evaluate type I as practically risk-free when it comes to disconnection. Accordingly, there is no hazardous zone present when using type I in combination with the - safe charging adapter. Using type II, there will be a risk of losing the adapter with the entire filling of 150 gram. In the worst case scenario with maximum 150 gram charge, it is seen that a small zone 2 of maximum ø 0,5m will be created, but it will only last for less than 10 seconds. The charging adapter ensures a proper connection. Using the adapter together with the safe charging adapter type I, it can be defined as a no zone charging area. There is, therefore, no demand of ventilation at this area. In a fourth aspect, the present invention also relates to a method for fire- and explosive safe charging of a refrigerant, where monitoring of gas inside the charging system is conducted by means of a gas sensor, and monitoring ventilation inside the charging system is conducted by a dP sensor or a flow sensor.

This makes it possible to assure the monitoring of a gas sensor where the cabinet must be ventilated and where the inside of the charging system is defined as zone 2. Therefore, the flow is monitored via a dP sensor or a flow sensor at the ventilation intake and if the flow inside the cabinets is not as specified, operation is not possible.

Ventilation is for example set to 100 m 3 /h, where the flow is monitored by a flow switch. An alarm level is for example set to 60 m 3 /h and if the flow is not achieved, further processes are then prevented, where e.g. all electricity in the zone is shut off. If the ventilation is set and the flow is monitored by a flow switch, the quick-connector to the system is opened. The monitoring of the flow is along with the monitoring of the gas essential to be able to start any of the processes.lt will then be tested, if the system has already been charged via pressure switch in the adapter. If already charged, the process is aborted.

A dP sensor or delta-P sensor is a Differential Pressure sensor.

In a fifth aspect, the present invention also relates to a method for fire- and explosive safe charging of a refrigerant, where the monitoring of gas inside the charging system is conducted by means of a gas sensor, defining at least two alarm levels, for example 10 % LEL and 25 % LEL. By using a gas sensor it is possible to detect any possible leakages inside of the charging system. Two alarm levels are defined for example: 10 % and 25 % LEL (LEL: Lower Explosive Limit), as a yellow and red alarm, respectively. In the event of a yellow alarm, all electrics in the zone are shut off, except the gas sensor. At red alarm level, the alarm must be send to the internal fire department or some other permanently supervised office.

In a sixth aspect, the present invention also relates to a method for fire- and explosive safe charging of a refrigerant, where the signals for operation permission comprise at least signals from the following:

• Activated purge flow switches,

• non-activated gas alarms,

• non-activated emergency stop/ overall emergency stop.

This makes it possible to assure that the desired flow is achieved within a certain time frame due to the flow switch, - if the desired flow is not achieved, the unit is shut down. Additionally, it makes it possible to detect leakages by means of the gas sensor and in case of any detected leakage, start-up will not be possible.

Furthermore, it is possible to ensure that neither the emergency stop nor the overall emergency stop of the power supply to the charging system is acti- vated and the supply is closed.

In a seventh aspect, the present invention also relates to a method for fire- and explosive safe charging of a refrigerant, where that supply of refrigerants to the charging station comprises at least the following step, where the charging station is supplied by a supply pump, drawing the refrigerant from e.g. bottles situated in a bottle cabinet. This makes it possible to integrate the supply pump into the bottle cabinet or the supply pump could be integrated into the charging station.

As alternative to the supply pump drawing the refrigerant from bottles situated in a bottle cabinet, the supply pump could just as well draw the refrigerant from a central a battery or any other storage of refrigerant available.

In an eighth aspect, the present invention also relates to a method for fire- and explosive safe charging of a refrigerant, where that supply of refrigerants to the charging station comprises at least the following step, where the refrigerant supply is conducted by e.g. a bottle supply, connected to one bottle at a time.

This makes it possible to conduct the refrigerant supply via a bottle supply only, where the supply is limited to 2 x 65 kg and where only one bottle is connected at a time. To enable a bottle-change during operation, the ventilation alarm has a delay of 10 min.

As alternative to the bottle supply, the supply could instead be a central supply line, a battery or any other storage of refrigerant available. In a ninth aspect, the present invention also relates to a method for fire- and explosive safe charging of a refrigerant, where the charging of the adapter implies a mechanical interlock.

This makes it possible to ensure a proper connection and, therefore, the charg- ing area can be classified as no hazardous zone.

In a tenth aspect, the present invention also relates to a method for fire- and explosive safe charging of a refrigerant, where evacuation is conducted by a vacuum system, pump or ejector etc. leading the gas to the outside via a ven- tilation system. This makes it possible to ensure the method and apparatus claimed and described accordingly, and to equip all tubes in which liquid or gaseous refrigerant may be trapped with safety valves according to EN378-1 and PED Dir. 2014/68/EU, where the outlet of the safety valve together with the outlet of a vacuum device, being e.g. a vacuum system, a vacuum pump, an ejector is ventilated to the outside via the ventilation system.

Another option is to use an evacuation adapter. Ejection test of this adapter is not necessary, as the coupler will be closed before the charging process will be commenced.

Therefore, normally there will be no refrigerant release at such an adapter.

In an eleventh aspect, the present invention also relates to a method for fire- and explosive safe charging of a refrigerant, where the method after stopping all functions comprises at least the following steps: closing at least one safety valve, turning off all power and disconnecting all refrigerant supplies.

This makes it possible to ensure that the interior (mechanical section) of the charging station is also turned off during control off in zone 2. During control off all power to the mechanical section is off - thus, there are no ignition sources left in the cabinets, and any further refrigerant supply is disconnected. Only one bottle is connected to the system at a time and ventilation is cut off. When the charging system is switched off, the safety closing valve will be closed.

Inside the bottle cabinet, electricity is also cut off during control off - except for the gas sensor. The safety closing valve inside the bottle cabinet is also closed. The gas sensor must be supplied via an uninterruptible power supply, and power to the ventilation system is activated - a certain delay for the ventilation alarm is necessary to allow the flow to build up or the red Alarm is automatically set to the internal Fire department or any other permanently supervised office, if the power is cut off, or fails.

The gas sensor is activated during start-up. In case of any detected leakage, the start-up will not be possible. The zone inside the entire mechanical sections of the system is defined as zone 2.

Therefore, all electrical items in this area must comply to ATEX directive 2014/34 EU (device category 3G). In a twelfth aspect, the present invention also relates to a method for fire- and explosive safe charging of a refrigerant, where stopping of the functions comprises at least the following: an ordinary process stop button, a control off switch and an emergency stop button. This makes it possible to equip the unit with three different stop functions. Besides, areas, which handle or stores refrigerant, must be ventilated to prevent dangerous accumulation of refrigerant gasses.

According to a thirteenth aspect, an apparatus for a fire- and explosive safe charging of a refrigerant is claimed, where the apparatus according to claims 1 to 12 comprises at least:

a charging station comprising at least one charging adapter and a ventilation inlet, where the charging station is connected to e.g. a bottle supply cabinet with a ventilation outlet. As alternative to the bottle supply, the supply could also be from a central supply line, a battery or any other storage of refrigerant available.

This makes it possible to assure safe operation during a production line charg- ing of air conditioners/refrigerators, (called RAC systems), using flammable refrigerants such as R600a and R290. ATEX 2014/34/EC and 99/92/EC regulations could be met if the installation is approved by local authorities before operation.

In a fourteenth aspect, the present invention also relates to an apparatus for fire- and explosive safe charging of a refrigerant, where the apparatus further comprises a supply pump at least in one of the following places: the charging station, the bottle supply cabinet, a separate unit between the bottle supply cabinet and the charging station.

This makes it possible to draw the refrigerant from the bottles situated in a bottle cabinet to the charging area.

The charging station can be supplied locally by a supply pump, or another option is to integrate it into the bottle cabinet, or as an even further option, integrate it into the charging station.

In a fifteenth aspect, the present invention also relates to an apparatus for fire- and explosive safe charging of a refrigerant, where the apparatus comprises a safety emergency relay connected to at least one of: a gas sensor, an alarm lamp tower, a dP-sensor, flow sensor, an emergency stop.

This makes it possible to utilize a gas sensor for gas monitoring and avoid any leakage and accumulation of explosive atmosphere. For correct ventilation monitoring, the flow-sensor must always be placed at the ventilation intake, and the gas sensor in the outlet cabinet. If flow is not achieved, the units are put to yellow alarm level, and further process is prevented.

Description of the Drawing

The invention will be described in further detail below by means of non-limiting embodiments with reference to the drawing, in which:

Figures 1 to 4 show an apparatus for a fire- and explosive safe charging of a refrigerant in various schematic system layouts,

Figure 5 shows a charging adapter with a tube adapter quick-connector, Figure 6 shows a charging adapter with a threaded adapter quick-connector, Figure 7 shows a charging adapter 3 with a tube adapter quick-connector in another embodiment,

Figure 8 shows a safety emergency relay and its connections,

Figures 9 and 10 show a charging station and a charging adapter.

In the drawings, the following reference numerals have been used for the designations used in the detailed part of the description:

1 Apparatus for a fire- and explosive safe charging of a refrigerant

2 Charging station

3 Charging adapter

3a Mechanical interlock

4 Ventilation inlet

5 Bottle supply cabinet

6 Ventilation outlet

7 Supply pump

8 Charging area

9 Tube adapter quick-connector 10 Threaded adapter quick-connector

1 1 dP sensor or a flow sensor

12 Gas sensor

13 Safety emergency relay

14 Gas sensor

15 Alarm lamp tower

16 dP-sensor or a flow sensor

17 Emergency stop

18 Safety shut off valve

19 Vacuum device

Detailed Description of the Invention

Figures 1 to 4 show an apparatus 1 for a fire- and explosive safe charging of a refrigerant in a schematic system layout.

Figure 1 shows an apparatus 1 for a fire- and explosive safe charging of a refrigerant, where the apparatus 1 comprises a charging station 2, two charging adapters 3, a ventilation inlet 4, and where the charging station 2 is connected to a bottle supply cabinet 5 with bottles 5a, 5b and where the supply cabinet 5 has a ventilation outlet 6.

The apparatus 1 further has a supply pump 7 as a separate unit between the bottle supply cabinet 5 and the charging station 2.

The figure shows the apparatus 1 schematically at a charging area 8, where the charging area 8 for instance could be a conveyor, where the fire- and explosive safe charging of a refrigerant to refrigerators, air conditioning units, etc., take place. Inserted figure 1 a shows the charging adapter 3, figure 1 b shows a tube adapter quick-connector 9 and figure 1 c shows a threaded adapter quick-connector 10. Figure 2 shows an apparatus 1 for a fire- and explosive safe charging of a refrigerant, similar to the apparatus 1 shown in figure 1 but seen from the side, with the supply pump 7 as a separate unit between the bottle supply cabinet 5 and the charging station 2. Furthermore, a dP sensor or a flow sensor 1 1 for detection of negative pressure/ventilation inside the charging station 2 is shown at the ventilation inlet 4, and a gas sensor 12 with 2 programmable built in alarm levels.

Figure 3 shows an apparatus 1 for a fire- and explosive safe charging of a refrigerant, seen from the side, where the supply pump 7 is built into the bottle supply cabinet 5.

Figure 4 shows an apparatus 1 for a fire- and explosive safe charging of a refrigerant, seen from the side, where the supply pump 7 is built into the charging station 2.

A vacuum system, ejector etc. pump 19 leading the gas to the outside via the ventilation system is for example positioned inside the charging station 2, with the supply pump 7 or inside the bottle supply cabinet 5 and, thus, is just randomly indicated at figures 1 to 4.

Figures 5 to 7 show a charging adapter 3 with one of the quick-connectors 9 or 10, in a schematic configuration layout. Figure 5 shows a charging adapter 3 with a tube adapter quick-connector 9, used when charging below 150 gram refrigerant of the adapter 3, also mentioned as a type I safe charging adapter, where metallic claws are used to grip onto the tube.

Figure 6 shows a charging adapter 3 with a threaded adapter quick-connector 10 used when charging above 150 gram but below 1000 gram refrigerant of the adapter 3.

Both situations shown in figure 5 and figure 6 are used in no zones for fire- and explosive safe charging of a refrigerant, which means that no ventilation is required at the charging adapter, hence, a fire- and explosive safe charging is present.

Figures 7 shows a charging adapter 3 with a tube adapter quick-connector 9 used when charging below 150 gram refrigerant of the adapter 3 but where the adapter is to be used with a gasket, also mentioned as a type II tube adapter, where a gasket gripping is used, whereby a zone 2 is obtained when used for fire- and explosive safe charging of a refrigerant, which means that an exceptional and only short escape of a gas within a defined area of ø 0,5 metre from the charging adapter can occur.

The charging adapter 3 implies a mechanical interlock 3a, which is positioned inside the charging adapter 3 and, thus, is just indicated in figures 5 to 7. Figures 8 shows a safety emergency relay 13 and its connections to a gas sensor 14, which monitors gas inside the charging system, the safety emergency relay 13 being further connected to an alarm lamp tower 15, and to a flow sensor, or dP-sensor 16 which detects negative pressure/ventilation inside the charging system and the safety emergency relay 13 is also connected to an emergency stop 17. The safety emergency relay 13 is also connected to the charging station 2 and the bottle supply cabinet 5 which are both equipped with a safety shut off valve 18, which is normally a closed pneumatic valve.

Figures 9 and 10 show a charging station 2 and a charging adapter 3.

Figure 9 shows a no zone (non-hazardous zone) situation, where the charging adapter 3 and the system to be charged are leakage-checked prior to a charging process, where no ventilation is, therefore, required at the charging adapter 3.

Figure 10 shows a zone 2 (reduced zone) situation, where the charging adapter 3 and the system to be charged is leakage-checked prior to a charging process, where the zone at the charging adapter is ø 0,5m, where no ventilation is, therefore, required at the charging adapter 3.