EP0431335B1 - Refrigerant discharging device for absorption refrigeration systems - Google Patents

Description

The invention relates to a device for environmentally friendly emptying and disposal of absorption refrigeration systems.

Since the realization that the fluorinated chlorinated hydrocarbons used as refrigerants in compressor-operated systems pose an environmental risk because they can damage the ozone layer, refrigeration devices have been hazardous waste that must be disposed of properly. Functional extraction systems with which the refrigerant can be collected and recycled (e.g. EP-A-0 328 475 or Wo 89/06336) were soon developed for compressor-operated refrigeration systems, the refrigerant of which is primarily the chlorofluorocarbon R12.

In addition to compressor-operated refrigeration devices, there are also other types of refrigeration systems that are based on the absorption principle. These refrigeration systems cannot be disposed of using the techniques developed for compressor operated refrigeration equipment. Refrigeration devices based on absorption therefore accumulate in large quantities in the depots for municipal waste disposal and in specialist disposal companies.

In conventional absorber refrigeration devices, such as those used in particular in hotels, restaurants and in the camping sector, but also in the household, the refrigeration cycle is operated with an ammonia / water / auxiliary gas mixture. Hydrogen or helium is primarily used as the pressure-equalizing auxiliary gas. For corrosion protection reasons, not inconsiderable amounts of Na2Cr04 are added as a corrosion inhibitor. Absorber refrigeration units usually contain about 250 g to 700 g of refrigerant in the following composition:

There are also small amounts of hydrogen or helium by weight. Of these substances, ammonia and chromate are considered to be environmentally harmful.

The refrigerant in absorber refrigeration devices is under increased pressure, usually up to 25 bar. In contrast to the refrigerant contained in the compressor unit, it does not evaporate when the pressure is released, but remains in liquid form in the now open cooling system.

The ammonia contained in the refrigeration system is eagerly absorbed by water; at 20 ° C 100 ml of water dissolve about 52 g of NH3. For this reason, even in the event of leaks, most of the ammonia can remain in the aqueous solution of the refrigeration system.

Although ammonia is formed in many ways even in natural processes and has a relatively low toxicity, health impairments can occur at higher concentrations, which make regulated disposal appear necessary.

The sodium chromate also contained in the refrigeration system, on the other hand, represents a considerably greater risk. Chromium compounds and especially chromates are known to be highly carcinogenic and can also lead to serious allergies if they come into frequent contact. The sodium chromate contained in the refrigeration system of an absorption device also remains in the refrigeration device if there are any leaks.

Regardless of whether the refrigeration system in the absorber devices to be removed is under pressure or is depressurized, it is necessary to dispose of the refrigerant contained in the refrigeration system in a regulated manner. Suitable systems for such disposal have so far been lacking.

There are two main problems with the disposal of the liquid still in the refrigeration unit. On the one hand, it is difficult to remove the liquid from the refrigerator; even applying a vacuum or perforating the line several times does not lead to complete emptying. On the other hand, the chromate content deserves special attention. When an absorber system under pressure is opened, chromate-containing aerosols are initially formed during the pressure relief, which contain the chromate in tiny droplets (a few µm) that cannot be separated from the exhaust gas stream without problems. Appropriate Aerosols also arise when the refrigeration device is blown out with compressed air or another medium. Due to the small droplet size and therefore hardly any inertia behavior of these particles, adequate separation cannot be achieved even by simple exhaust gas deflection and arrangement of baffle elements. The existing MAK value for Cr with 100 mg / m³ exhaust gas cannot be met using conventional methods. In addition, this MAK value for Cr is often regarded as too high, so that a further decrease in the future cannot be excluded.

The invention is therefore based on the object of enabling safe disposal of the refrigerant from absorption devices which have a refrigeration unit which is still intact or has no pressure.

This object is achieved with a device of the type described in claim 1.

• Fig. 1 eine schematische Darstellung einer erfindungsgemäßen Anlage;
• Fig. 2 eine Ansicht des Druckbehältersystems;
• Fig. 3 eine Draufsicht auf das Druckbehältersystem von Fig. 2 und
• Fig. 4 einen Schnitt durch das Druckbehältersystem von Fig. 2;
• Fig. 5 eine Seitenansicht der Anlage von Fig. 2.

Preferred embodiments are the subject of the dependent claims and are explained in more detail below with reference to the figures, of which show

• Figure 1 is a schematic representation of a system according to the invention.
• 2 is a view of the pressure vessel system;
• Fig. 3 is a plan view of the pressure vessel system of Fig. 2 and
• FIG. 4 shows a section through the pressure container system from FIG. 2;
• 5 is a side view of the system of FIG. 2nd

According to a preferred embodiment of the system according to the invention, it essentially consists of two pressure vessels arranged on a mobile frame, which are integrated into a special pipeline construction. Each container has a safety valve, which is connected to the exhaust air chimney via a pipe system and a level indicator. The level indicator can also be a sight glass in the container wall.

The respective tank pressure is indicated by at least one manometer on one of the tanks. The container II has a water reservoir in the operating state, preferably with about half the filling. For filling there is a corresponding line which has a valve and preferably also a non-return device; Because of the increased tank pressure in the operating state, measures are necessary to prevent the filling of tank II from flowing back into the water supply network. A so-called pipe separator is particularly suitable for this.

The system has two pressure hose lines with special adapters for connection to the refrigeration units. These adapters should be designed for pipe diameters from 16 mm to 20 mm. Corresponding adapters are described in the applicant's parallel application DE-A-39 39 248 with the same filing date. The hose lines are connected to the pressure vessel system. A compressed air connection is available on tank I to blow out the refrigeration units.

Fig. 1 shows an embodiment of the system according to the invention with a first pressure vessel I and a downstream pressure vessel II, which are connected by a connecting line 29. The connecting line 29 is attached to the upper part of the pressure vessel I and ends in the lower half of the pressure vessel II. The pressure vessel II is approximately half filled with water so that line 29 ends below the water level.

Both pressure vessels have pressure gauges 34, 35 and pressure relief valves 36, 37 which are connected to the exhaust air line 31 via lines. This arrangement prevents harmful vapors from entering the installation room and endangering personnel in the event of incorrect operation or malfunction. The exhaust line 31 starts in the upper half of the container II; it can be closed by a valve 10. Both pressure vessels also have drain lines 28, 32 with drain valves 7, 8, which lead to a line to a collecting container for the refrigerant to be disposed of. The container II is also connected via a line 30 and a valve 9 to a fresh water supply. A check valve 13 is preferably located in this line.

The container I has connections for a separate compressed air line 27 with a valve 6 and a line 26 for the refrigerant to be disposed with a valve 5. The compressed air line 27 is fed via a compressor 23, which supplies compressed air with preferably approximately 18 bar, and via a throttle valve 11 with compressed air of approximately 7 bar. Compressed air can be supplied via line 27 to the two containers I and II when the valve 6 is open and can be blown out in this way when the valve 10 is closed and the valves 7 and 8 are open.

The pressure line 26 for the refrigerant to be disposed is connected on the side of the valve 5 remote from the container via a line 33 to the compressed air line 27, which supplies compressed air at a pressure of approximately 7 bar. The mouth of the compressed air line 33 is designed as an injector 12, which emits its compressed air flow in the direction of the container I and is able to generate a negative pressure of approximately 40 mbar in the line 26 on the side facing away from the container.

In this way it is ensured that, when a pressurized refrigerant line is pierced, refrigerant escaping is drawn into the pressure container I and does not get into the environment.

The pressure line 26 for the refrigerant to be disposed further has a valve 3 and continues to the second adapter 22, which is connected to the refrigeration system to be disposed of. The adapter 22 can be, for example, a gripper with attached, movably arranged mandrel, which is pressed into the refrigerant line to be pierced via a pressure nut through a rubber seal, as described in the above-mentioned patent application of the same day.

A line 25 with a valve 2 branches off from line 26 between injector 12 and valve 3. This line 25 opens into line 24, which connects the first adapter 21 for connection to the refrigeration system with the compressed air line from the compressor 23. Between the mouth of line 25 into line 24 and the branch from the compressed air line, which supplies a pressure of 18 bar, there is a valve 1 with which, when valve 2 is closed, compressed air via line 24 and adapter 21 to the item to be disposed of Refrigeration unit can be given, whereby the refrigerant enters the container I via the adapter 22 and the line 26. The valve 1 is preferably a time-controlled solenoid valve which is set to a time which is sufficient for the complete blowing out of all common absorber systems, for example about ten minutes.

The system according to the invention is operated as follows.

First, the container II is filled about half with water. This can be checked, for example, via a sight glass 39. Valves 1 to 8 are closed, valves 9 (fresh water) and 10 (ventilation) are open.

To relieve the pressure of a refrigeration unit to be disposed of, the adapter 21 is attached to the refrigeration unit, preferably in the vicinity of the storage container, and the pipe system is opened with the piercing device integrated in the adapter. Valves 1 and 3 and 6 to 9 are closed and 2, 4, 5 and 10 are open so that the pressure of approx. 25 bar can escape into pressure vessel I; as a result, the lines 24, 25 and 26 are released into the pressure vessel I. Compressed air of about 7 bar enters the injector 12 via the line 33 and the valve 4 and generates a slight negative pressure in the line 26, which ensures that the hydrogen escaping from the pierced refrigeration unit with its saturation content ammonia in the container I and arrives in the water reservoir of container II where the major part of the ammonia vapor is absorbed and the hydrogen reaches the atmosphere through the exhaust air line 31 and the opened valve 10.

After the pressure equalization has been established, the adapter 22 is attached in the area of the water separator / condenser of the refrigeration unit.

To blow out the refrigerant into pressure vessels I and II, valves 1, 3, 5 and 10 are opened and valves 2, 4 and 6 to 9 are closed. As a result, a compressed air flow of approximately 17 l / s and 18 bar is applied to the refrigeration unit. In the case of a time-controlled solenoid valve 1, a defined period of ten minutes is usually sufficient to empty the cooling unit.

The refrigerant is flushed through the line 26 and the opened valves 3 and 5 into the pressure container I, while the ammonia-containing air flow is passed through the water reservoir in the container II, where the ammonia part is largely absorbed is and the cleaned air reaches the atmosphere via line 31 and valve 10. Most of the chromate contained in the refrigerant remains with the refrigerant in pressure vessel I; A small proportion is carried along with the compressed air into tank II, where it is separated in the water reservoir. The exhaust air flowing out via line 31 therefore only has chromate particles in a concentration below the permissible values.

After about 80 to 100 blow-out processes, the containers I and II are filled or saturated with ammonia vapor so that further disposal is no longer possible. For emptying and the container, valves 1 to 5 and 9 and 10 are closed and 6 and one of 7 and 8 are opened so that compressed air can be supplied to container I via line 27 and valve 6. When the valve 7 is open, the container I is emptied via the valve 7 and the line 28 into a collecting container for such waste. When the valve 7 is closed and the valve 8 is open, the pressure vessel II is emptied into the collecting vessel via the line 32.

For the operation of the system according to the invention, it is advantageous to connect the adapters 21, 22 and the compressor 23 to the system according to the invention via hose quick couplings. Correspondingly, the collecting container for the collected refrigerant can also be connected via a quick coupling, in which case a transparent hose line makes it easier to follow the decanting process.

Fig. 2 shows a pressure vessel system according to the invention in front view. The two pressure vessels I and II are connected to one another in the manner described above by the connecting line 29. The container II has a manometer 35 and a valve 10 with the exhaust air line 31 at its upper end. The pressure lines of the pressure relief valves 36, 37 open into the exhaust air line 31 (covered).

At the bottom of the containers I and II are the drain lines 28 and 32 with the valves 7, 8 (covered). The container II also has a fresh water supply 30 with a shut-off valve 9 and a check valve 13.

Both containers I, II are provided with sight glasses 39 which allow the liquid level to be checked.

The compressed air is supplied via line 24. This leads via line 27, throttle valve 11, line 33, valve 4 and injector 12 into line 26, which leads into container I after passing valve 5.

The line 24 leads via the valve 1 to a quick hose connection 41, via which it then continues as a pressure hose 24 to the first adapter 21. The line 25 connects the line 24 via the valve 2 with the line 26 and the container I.

The second adapter 22 is connected to the line 26 with the valve 3 by means of a hose via a hose quick connector 42. To blow out a refrigeration unit, compressed air can be applied to the refrigeration unit to be drained via the pressure line 24 with the valve 1 and valve 2 closed, via the hose quick connector 41, a pressure hose 24 connected to it and the adapter 21, so that the refrigerant via the adapter 22 Hose quick connector 42, the valve 3, the line 26 and the opened valve 5 is pressed into the container I. Valves 2 and 4 are closed.

The compressed air line 27 opens via the valve 6 into the container I, which can thus be emptied via the line 28 when the valve 7 is open and the valve 10 is closed.

The lines 26 and 27 preferably open tangentially into the container in order to avoid splashing.

FIG. 3 shows a top view of the device according to the invention according to FIG. 2. The pressure vessels I and II, which are closed in a conventional manner on the top, each have a pressure gauge 34, 35 and pressure relief valves 36, 37, which are connected via a line the exhaust line 31 are connected. The exhaust air line 31 has a valve 10. The two containers I and II are connected to one another via the connecting line 29. Sight glasses 39 enable the liquid level to be checked.

FIG. 4 shows a section through the system according to the invention according to FIG. 2 along the line A - A. The containers I and II are connected via the connecting line 29 (partially shown). The line 26 leads via the injector 12 and the valve 5 tangentially into the container I; likewise the compressed air line 27 leads tangentially into this container via the valve 6. In an underlying level there are compressed air, refrigerant and drain lines with the corresponding valves.

The container II is supplied with fresh water via the line 30 and the valve 9, a check valve 13 preventing water from flowing back into the line from the possibly pressurized container. Instead of the check valve, a pipe separator can also be provided, which consists of a solenoid valve and a component that combines the functions of a backstop and an overflow. The solenoid valve shuts off the fresh water supply during operation, the backstop prevents dirty water from flowing back into the fresh water line, and with the help of an overflow designed in the manner of a siphon, the water between the solenoid valve and the backstop can be drained off, so that fresh water and Dirty water is safely avoided.

Both containers I and II are equipped with sight glasses 39 for checking the liquid level.

The container II also has a ring line 38 in its interior, into which the line 29 opens. This ring line has numerous perforations pointing downwards or obliquely downwards, which allow the gas flowing in via line 29 to exit below the water surface in container II. This enables the absorption of ammonia and the washing out of chromate.

FIG. 5 is a side view of a pressure vessel I used according to the invention according to FIG. 2 with a pressure gauge 34, a pressure relief valve 36, the discharge line 28 together with valve 7. In the background the exhaust line 31 is indicated, in the foreground parts of the connected line system.

The system according to the invention is particularly suitable for mobile use. To do this, it can be mounted on a trolley or on a truck.

Claims (9)

1. Apparatus for emptying and disposing of the coolant from absorption refrigerating apparatus of which the coolant contains an auxiliary gas, water as a solvent and a corrosion inhibitor, with a first and second adapter (21, 22) for connection to the refrigerating apparatus to be emptied, an air compressor or a compressed air connection (23), which is connected to the first adapter (21) by means of a compressed air line (24), which can be sealed off, and an associated valve (1), a first pressurized container (I), which is connected to the second adapter (22) via a pressure line, (26) which can be sealed off, and associated valves (3, 5), and includes an outlet (28) with a valve (7) for the fluid accumulated in the container, with a second pressurized container (II) which is connected by means of a connection line (29) to the first pressurized container and includes a fresh water supply line (30), an exhaust air line (31) and an outlet (32) with a valve (8), wherein the connection line (29), emerging from the upper end of the first pressurized container (I), leads into the lower half of the second pressurized container (II), and wherein the second pressurized container is approximately half filled with water for emptying the refrigerating apparatus, and the valves (1, 3, 5) are open.
2. Apparatus according to claim 1, characterized in that there is disposed in the pressure line (26), connecting the first adapter (21) to the first pressurized container (I), an injector (12) which is connected by means of a valve (4) and a compressed air line (33) to the compressor or compressed air connection (23).
3. Apparatus according to claim 2, characterized in that a throttle valve (11) is disposed in the compressed air line (33).
4. Apparatus according to claim 2 or 3, characterized in that a second valve (3) is disposed in the pressure line (26) connecting the first pressurized container (I) to the second adapter (22); in that the pressure line (26) is guided together with a further pressure line (25), which is connected to the compressed air line (24) and includes a valve (2), behind the valves (2, 3); and in that the injector (12) is disposed in the common section in front of the valve (5).
5. Apparatus according to any one of claims 1 to 4, characterized in that the valve (1) in the pressure line (24) is a time-controlled solenoid valve.
6. Apparatus according to any one of claims 1 to 5, characterized in that the connection line (29) leads into a gas distributor in the container (II).
7. Apparatus according to claim 6, characterized in that the gas distributor is a horizontal closed circular pipeline with downwardly directed gas outlet openings.
8. Apparatus according to any one of claims 1 to 7, characterized in that the exhaust air line (31) includes a valve (10) and a separate compressed air line (27) is guided via a valve (6) into the container (I) in order to blow out the containers (I, II).
9. Apparatus according to any one of claims 1 to 8, characterized in that it is mounted so as to be movable.

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