Method and device for drawing off a refrigerant and a state unit

Abstract

Method and apparatus for extracting a refrigerant with an extraction station (13), characterized in that before extraction it is determined (2) which refrigerant is used, that during extraction it is repeatedly determined (3) what pressure and temperature the refrigerant has, that a phase state of the refrigerant is determined from the pressure and temperature (4) and that an extraction valve of the extraction station (13) is controlled on the basis of the phase state of the refrigerant (6, 7).

Description

[0001] The invention relates to a method for extracting a refrigerant using an extraction pump.

[0002] Refrigeration systems, such as air conditioners and heat pumps, use a refrigerant in a refrigerant cycle to achieve the corresponding heating and / or cooling effect.

[0003] There are situations in which the refrigerant must be removed from the refrigerant circuit, for example when a refrigeration system requires repair.

[0004] To remove refrigerant from a refrigerant circuit, it is known in the prior art to use a recovery station. Such a recovery station has a recovery valve on the inlet side, which is connected to the refrigerant circuit to be recovered, for example, a service port of the refrigeration system. The recovery station also has a recovery pump, which is connected on the outlet side to an empty refrigerant cylinder. The recovery pump compresses the gaseous refrigerant and pumps it into the refrigerant cylinder. Therefore, it is necessary for the refrigerant to be in a gaseous state during recovery.

[0005] Depending on the ambient conditions, the refrigerant in the refrigerant circuit may not be completely gaseous, but at least partially liquid. Since a liquid is incompressible, the recovery pump cannot operate at full capacity in this situation and may even be damaged. This manifests itself, for example, as knocking or jumping / bouncing of the recovery unit.

[0006] Currently, the technician listens for unusual noises from the suction pump during the extraction process and then, if necessary, reduces the flow of liquid to the pump by narrowing the opening of the suction valve. To avoid such undesirable conditions, current best practices also include operating the valve permanently with the smallest possible opening or reducing the cross-section of the pipes to prevent damage to the pump. However, this unnecessarily prolongs the extraction process.

[0007] The object of the invention is therefore to improve the extraction process.

[0008] This problem is solved according to the invention by a method according to claim 1, a device according to claim 9 and a state unit according to claim 12.

[0009] The method according to the invention is characterized in that, before extraction, the refrigerant used is determined, the pressure and temperature of the refrigerant are repeatedly determined during extraction, a phase state of the refrigerant is determined from the pressure and temperature, and an extraction valve of the extraction pump is controlled based on the phase state of the refrigerant.

[0010] This allows for the objective determination of the refrigerant's phase state, i.e., whether liquid components are present. This enables the recovery valve to be controlled to achieve its maximum opening without causing a critical or undesirable condition of the recovery pump, which occurs when at least some liquid refrigerant is present. Therefore, it is no longer necessary to "listen" to the pump's condition to adjust the recovery valve.

[0011] The phase state of the refrigerant can change along the route from the refrigeration system to the extraction station, so it may be advantageous to determine the pressure and / or temperature at or near the inlet of the extraction station.

[0012] In one version, the suction valve of the suction pump is automatically controlled depending on the phase state of the refrigerant. This eliminates the need for user intervention and allows for optimal automated control of the suction valve opening.

[0013] In an alternative embodiment, a message regarding the position of the suction valve is issued to control the suction valve, allowing a user of the suction pump to adjust the valve. In this way, the method according to the invention can also be used with suction stations that, for example, do not allow automatic control of the suction valve.

[0014] In one version, the instruction regarding the position of the control valve includes an absolute valve position. For this purpose, the instruction could, for example, include a graphic representation of an operating element of the suction valve.

[0015] Additionally or alternatively, the instruction may include directional guidance for moving a control element of the suction valve. This may include, for example, whether the opening of the suction valve should be decreased or increased. It may also include whether a control element of the suction valve should be moved up, down, right, or left.

[0016] In one version, the warning also includes a representation of the refrigerant's phase state. This allows the user to directly identify the phase state. It may also be possible to manually adjust the valve position based on this representation, even with automatic control of the extraction valve.

[0017] To determine the phase state of the refrigerant, it is first necessary to identify the refrigerant. This is practically done manually, for example using a table or database.

[0018] Alternatively, the refrigerant can be automatically detected using a refrigerant sensor. This allows, for example, fully automated extraction.

[0019] In one version, the pressure is automatically determined by a pressure sensor.

[0020] In one version, the temperature is automatically determined by a temperature sensor.

[0021] The automated determination of the refrigerant parameters allows for repeated determination of the phase state.

[0022] In one implementation, a phase diagram is assigned to a refrigerant. Based on the determined pressure and temperature, the phase state of the refrigerant is determined using the assigned phase diagram.

[0023] In one embodiment, the opening of the extraction valve is reduced when a liquid phase of the refrigerant is detected, and the opening is increased when a gaseous phase of the refrigerant is detected. This prevents liquid refrigerant from entering the extraction pump.

[0024] The invention further comprises a device for extracting refrigerant, comprising an extraction pump and an adjustable extraction valve, characterized in that the device further includes a state unit, wherein the device has a pressure sensor and a temperature sensor, and the state unit is configured to determine a phase state of the refrigerant, and the extraction valve is adjustable depending on the phase state. With such a device, it is possible to carry out an extraction process quickly and safely. Damage to the extraction pump that can occur from the intake of liquid refrigerant is thereby prevented.

[0025] In one version, the suction valve is automatically controlled depending on the phase state. This enables fully automatic suction, whereby the suction process takes place as quickly as possible without damaging the suction pump.

[0026] In one embodiment, the device additionally or alternatively features a guidance unit designed to provide a signal for manually adjusting the extraction valve based on the phase state of the refrigerant. This allows for manual control of the extraction valve, based on objective criteria rather than relying on sound as before.

[0027] In one version, the warning unit is equipped for the visual display of the warning. For this purpose, the warning unit can include, for example, a screen or individual optical elements such as LEDs.

[0028] Such a device could, for example, be a suction station. The suction station preferably includes the suction valve and the suction pump. The state unit can be a separate device, independent of the suction station.

[0029] In one embodiment, the pressure sensor is located in the suction station. This allows the pressure to be measured directly at the suction pump inlet. It is advantageous to have a connection for transmitting the pressure values ​​to the control unit. This connection can preferably be wireless.

[0030] In one embodiment, the pressure sensor is located within the state unit. This allows the pressure to be determined even if, for example, the extraction station does not have a pressure sensor or a connection for transmitting the pressure value.

[0031] In one version, the temperature sensor is an external temperature sensor. Such a temperature sensor can, for example, be attached to a refrigerant line near the extraction station using a clamp, in order to determine a temperature value close to the extraction station.

[0032] The temperature sensor can also be located in the state unit.

[0033] In one embodiment, the device is set up to carry out a method according to the invention.

[0034] The invention also comprises a state unit with at least one refrigerant inlet, one refrigerant outlet, one pressure sensor, and one temperature sensor, wherein the state unit is configured to determine a phase state of the refrigerant and wherein the state unit is configured to control the extraction valve depending on the phase state. This state unit is preferably designed as a separate device. In this way, the extraction method according to the invention can be carried out with any conventional extraction station.

[0035] The invention is explained in more detail below with reference to exemplary embodiments and the accompanying drawings.

[0036] It shows: Fig. 1: a flowchart of a method for extracting refrigerant, Fig. 2: a block diagram of a first embodiment of a device for extracting refrigerant, Fig. 3: a block diagram of a first embodiment of a device for extracting refrigerant, Fig. 4: a block diagram of a first embodiment of a device for extracting refrigerant, Fig. 5: a block diagram of a first embodiment of a device for extracting refrigerant, and Fig. 6: a schematic representation of a guidance unit.

[0037] The Fig. 1 shows a flowchart of a method 1 according to the invention for extracting a refrigerant from a refrigeration system.

[0038] In the first step (step 2), the refrigerant used or to be extracted is identified. This step is usually performed before the extraction process begins. Refrigerant identification can be done manually, for example via a selection list, or automatically, for example using a sensor.

[0039] In a second step, the pressure and temperature of the refrigerant are determined. Both parameters are preferably determined automatically using sensors.

[0040] In a third step (4), the phase state of the refrigerant is determined based on the pressure and temperature. A phase diagram can be assigned to each refrigerant, for example, stored in a database. The phase state can then be determined from this phase diagram using the pressure and temperature.

[0041] In a fourth step 5, the phase state is now checked to determine whether the refrigerant is purely gaseous or at least has a liquid component.

[0042] If a liquid component is present in the refrigerant, or if the liquid component is greater than in the last measurement, the opening of a vent valve is reduced in a fifth step (6). This can be done manually by a user. A message can be issued to the user, which may include, for example, the position of the vent valve and / or the direction in which the vent valve must be moved. The message can also include the current phase state.

[0043] Alternatively, the reduction of the opening of the suction valve can also be done automatically.

[0044] If the refrigerant contains no liquid or less than in the last measurement, the opening of the extraction valve is enlarged in an alternative sixth step (7). If further opening is no longer possible, i.e., the maximum opening has already been reached, this opening is maintained.

[0045] Here too, analogous to reducing the opening, the opening of the suction valve can be increased manually and / or automatically.

[0046] In this way, it is always possible to carry out the extraction process at the maximum possible speed, because the extraction valve is always open as far as possible without causing damage to the extraction pump.

[0047] The reduction or enlargement of the suction valve opening, whether manual or automated, can correlate with the liquid concentration. This means that the higher the liquid concentration, the greater the reduction / enlargement, i.e., the more the suction valve is closed / opened. This prevents liquid from entering the suction pump and ensures that the maximum possible opening is always maintained. In this way, a phase state can correlate directly, i.e., absolutely, with the opening of the suction valve, eliminating the need for a relative consideration of the previous phase state.

[0048] In a subsequent seventh step 8, it is determined whether the system to be extracted is already empty.

[0049] If this is the case, the extraction process is terminated in step 9.

[0050] If the system is not yet empty, proceed to step 3 and determine the pressure and temperature again.

[0051] The Fig. 2 Figure 1 shows a block diagram of a first device 10 for extracting a refrigerant from a refrigeration or air conditioning system 11. Such a refrigeration or air conditioning system 11 could be, for example, an air conditioner or a heat pump.

[0052] The device 10 has a state unit 12 and a suction station 13, which in this example are designed as separate devices.

[0053] The recovery station 13 has a recovery valve 14 and a recovery pump 15. Internally, the recovery valve 14 is connected to the recovery pump 15. This means that the recovery valve 14 determines the amount of refrigerant that reaches the recovery pump 15. The recovery station 13 is connected to a refrigerant pressure cylinder 16. The recovered refrigerant is compressed by the recovery pump 15 into the refrigerant pressure cylinder 16.

[0054] The state unit 12 has a high-pressure inlet 17 and a low-pressure inlet 18. These are connected to the high-pressure circuit 19 and the low-pressure circuit 20 of the system 12, respectively, for extraction.

[0055] The state unit 12 has an output 29 which is connected to or is connected to the suction valve 14 of the suction station.

[0056] In the example shown, the state unit 12 has a pressure sensor (not shown) at the high-pressure inlet 17 and at the low-pressure inlet 18, and at least one temperature sensor, all integrated within the state unit 12. Furthermore, the state unit 12 has a memory containing phase diagrams for various refrigerants. The state unit 12 is configured to determine a phase state from the refrigerant's pressure and temperature. This phase state indicates the proportion of liquid, if any, present in the refrigerant.

[0057] In this example, the state unit 12 has a control connection 21 to the extraction station 13, via which the extraction valve 14 can be controlled. The extraction valve 14 has, for example, an electromechanical actuator for this purpose. Additionally, the extraction valve 14 may have a manual control element.

[0058] According to the procedure of Fig. 1 The opening of the extraction valve 14 is therefore reduced when the refrigerant contains a liquid component, and increased when less liquid is present. In this way, automatic and continuous control of the extraction valve 14 is enabled, ensuring that the extraction process takes place at maximum speed.

[0059] Before an automatic evacuation process can be started, the refrigerant must first be selected. For this purpose, state unit 12 can have a screen, such as a touchscreen, on which a selection list of different refrigerants is initially displayed, and from which the refrigerant to be used is selected. State unit 12 can additionally or alternatively have an interface to an external control system, such as an app, through which the refrigerant can be selected, so that the state unit can also function without its own screen.

[0060] The Fig. 3 Figure 10 shows another embodiment of a device 10 for extracting refrigerant. Functionally identical features to the Fig. 1 are marked with the same reference symbols.

[0061] The extraction station 13 here only has a manually adjustable extraction valve 14. This means there is no control connection to the state unit 12. The extraction valve 14 has a control element (not shown) by which the opening of the extraction valve 14 can be adjusted.

[0062] The state unit 12 has a notification unit 22 for this purpose, such as a screen for the graphical display of instructions for controlling the extraction valve 14. A valve position is derived from the phase state of the refrigerant and displayed graphically. A user can then adjust the extraction valve 14 at the extraction station 13 accordingly using the control element. The advantage here is that the user receives objective information for controlling the extraction valve and no longer has to rely on guesswork.

[0063] The Fig. 4 shows another embodiment of device 1, which is similar to the Fig. 2 The extraction station 13 has a pressure sensor, located approximately at the inlet of the extraction valve 14, which is connected to the state unit 12 via a control connection 23. In this way, pressure values ​​can be transmitted to the state unit 12.

[0064] Furthermore, an external temperature sensor 24 is provided, which is arranged on a refrigerant line near the extraction valve 14. The temperature sensor 24 also has a control connection 25 to the state unit 12 for transmitting the temperature values. In this embodiment, the state unit 12 can additionally have internal pressure and / or temperature sensors. However, for determining the phase state, the externally determined pressure and temperature values ​​are preferably used here, since these are determined closer to the extraction valve 14. The extraction valve 14 is automatically controlled by the state unit 12 via the control connection 21.

[0065] In all versions, the control connections 21, 23 and / or 25 can be implemented as a wired or wireless connection, for example as a radio connection such as via Bluetooth.

[0066] The Fig. 5Figure 1 shows another alternative embodiment of a device 10 for extracting refrigerant. In contrast to the previous embodiments, the state unit 12 is integrated into the extraction station 13. Extraction station 13 and state unit 12 are thus combined in one device. The state unit 12 has an internal control connection 21 for the automatic control of the extraction valve 14.

[0067] In addition to the versions shown here, it is of course possible to combine the individual components of each version in any way you like. For example, even with the Fig. 5 An external temperature sensor can be used, which can be connected to the internal state unit 12.

[0068] It is also possible that the state unit 12 of the Figs. 2 to 4 and also the suction station 13 of the Fig. 5It only has one inlet for connection to a refrigerant circuit. In this case, the high-pressure circuit and the low-pressure circuit must be evacuated separately, one after the other, with the connection being changed each time.

[0069] The invention is not limited to the embodiments shown.

[0070] The Fig. 6 Figure 22 shows an example of a visual indicator unit for displaying information. The example shows a representation 26 of a control element for a suction valve 14, which indicates an absolute position. With such an indicator, the suction valve 14 can be controlled quickly and relatively accurately.

[0071] Additionally or alternatively, the indicator unit 22 has direction indicators 27, which show, for example, in which direction a control element of the extraction valve 14 should be moved.

[0072] Furthermore, the indicator unit 22 can additionally display a representation 28 of the phase state, which graphically represents the proportion of liquid. Reference symbol list

[0073] 1. Procedure 2. First step 3. Second step 4. Third step 5. Fourth step 6. Fifth step 7. Sixth step 8. Seventh step 9. Eighth step 10. Device for extracting refrigerant 11. Refrigeration or air conditioning system 12. State unit 13. Extraction station 14. Extraction valve 15. Extraction pump 16. Refrigerant pressure cylinder 17. High-pressure inlet 18. Low-pressure inlet 19. High-pressure circuit 20. Low-pressure circuit 21. Control connection 22. Screen 23. Control connection p 24. External temperature sensor 25. Control connection T 26. Display of a control element 27. Direction indicator 28. Display of the phase state 29. Output of the state unit

Claims

1. Method for extracting a refrigerant using an extraction station (13), characterized by the fact that Before extraction, the refrigerant used is determined (2), the pressure and temperature of the refrigerant are repeatedly determined (3) during extraction, a phase state of the refrigerant is determined from the pressure and temperature (4), and an extraction valve of the extraction station (13) is controlled based on the phase state of the refrigerant (6, 7).

2. Method according to claim 1, characterized by the fact that The extraction valve (14) of the extraction station (13) is automatically controlled depending on the phase state of the refrigerant.

3. Method according to claim 1, characterized by the fact that To regulate the suction valve, a note regarding the position of the suction valve (14) is issued, according to which a user of the suction pump can set the suction valve (14).

4. Method according to claim 3, characterized by the fact thatThe indication regarding the position of the extraction valve (14) includes a representation (26) of the operating element of an extraction valve (14) and / or a directional indication (27) for the movement of an operating element of the extraction extraction valve (14), preferably wherein the indication also includes a representation (28) of the phase state of the refrigerant.

5. Method according to any of the preceding claims, characterized by the fact that that the refrigerant is automatically determined by a refrigerant sensor and / or that the pressure is automatically determined by a pressure sensor and / or that the temperature is automatically determined by a temperature sensor (24).

6. Method according to any of the preceding claims, characterized by the fact that a phase diagram is assigned to a refrigerant, and the phase state of the refrigerant is determined according to the determined pressure and temperature using the assigned phase diagram (4).

7. Method according to any of the preceding claims, wherein the opening of the extraction valve is reduced (6) when a liquid phase state of the refrigerant is determined and the opening of the extraction valve is increased (7) when a gaseous phase state of the refrigerant is determined.

8. Device (10) for extracting a refrigerant, comprising an extraction pump (15) and an adjustable extraction valve (14) characterized by the fact that the device further comprises a state unit (12), wherein the device (10) comprises a pressure sensor and a temperature sensor and the state unit (12) is configured to determine a phase state of the refrigerant, and the extraction valve (14) is controllable depending on the phase state.

9. Device according to claim 8, characterized by the fact thatthe extraction valve (14) is automatically controlled depending on the phase state and / or that the device (10) has a guidance unit (22) which is configured to issue a guidance for manual control of the extraction valve (14) based on the phase state of the refrigerant, in particular wherein the guidance unit (22) is configured to provide an optical indication of the guidance.

10. Device according to one of claims 8 or 9, characterized by the fact thata pressure sensor is arranged in the extraction station (13), wherein a control connection (23) is provided for transmitting the pressure values ​​to the state unit (12) and / or that the temperature sensor is an external temperature sensor (24), wherein a control connection (25) is provided for transmitting the temperature values ​​to the state unit (12) and / or that the state unit (12) has a control connection (21) to the extraction station (13) for controlling the extraction valve (14) and / or that a pressure sensor is arranged in the state unit (12) and / or that the temperature sensor is arranged in the state unit (12).

11. Device according to one of claims 8 to 10, characterized by the fact that the device (1) is arranged in a device or that the state unit (12) is designed as a separate device and / or that the device (1) is set up to carry out the method according to one of claims 1 to 7.

12. State unit (12) with at least one refrigerant inlet (17, 18), with a refrigerant outlet (29), with a pressure sensor and with a temperature sensor, wherein the state unit (12) is configured to determine a phase state of the refrigerant and wherein the state unit (12) is configured to control the extraction valve (14) depending on the phase state, in particular according to the method according to one of claims 1 to 7.

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