KR20070092118A - Expansion valve - Google Patents

Abstract

An expansion valve is provided to move refrigerant of high humidity to a lower part of a temperature lowering part through a bypass path, thereby preventing a temperature of the refrigerant from rising excessively and a lubrication oil of a compressor from being temperature-deteriorated. An expansion valve includes a bypass path(3a,3b) formed between a high pressure refrigerant inlet supplied with refrigerant of high pressure or a low pressure refrigerant outlet for transmitting refrigerant of low pressure to an evaporator(4), and a refrigerant path through which refrigerant discharged from the evaporator flows. Through the bypass path, liquid refrigerant of high pressure or gas/liquid mixture refrigerant of low pressure flows to a lower part of a temperature lowering part.

Description

Expansion valve {EXPANSION VALVE}

1 is a system diagram showing a refrigeration cycle to which the expansion valve of the present invention is applied.

FIG. 2 is a central longitudinal cross-sectional view showing a configuration of the expansion valve according to the first embodiment. FIG.

3 is a central longitudinal sectional view showing a configuration of an expansion valve according to a second embodiment;

4 is a central longitudinal sectional view showing a configuration of an expansion valve according to a third embodiment.

5 is a central longitudinal cross-sectional view showing a configuration of an expansion valve according to a fourth embodiment.

6 is a central longitudinal cross-sectional view showing a configuration of an expansion valve according to a fifth embodiment.

FIG. 7 is a central longitudinal sectional view showing a configuration of an expansion valve according to a sixth embodiment. FIG.

8 is a central longitudinal cross-sectional view showing a configuration of an expansion valve according to a seventh embodiment.

<Explanation of symbols for main parts of the drawings>

1: compressor

2: condenser

3: expansion valve

3a, 3b: bypass passage

4: evaporator

5: internal heat exchanger

10: expansion valve

11: body

12: high pressure refrigerant inlet

13: low pressure refrigerant outlet

14: refrigerant passage inlet

15: refrigerant passage outlet

16: valve seat

17: valve body

18: valve body receiving part

19: compression coil spring

20: spring receiving part

21: adjusting screw

22: upper housing

23: lower housing

24: diaphragm

25: disk

26: shaft

27: refrigerant passage

28: holder

29: compression coil spring

30: bypass passage

31: valve seat

32: valve body

33: compression coil spring

34: spring receiving part

35: orifice

36: double pipe

36a: appearance

36b: inner tube

40, 50, 60, 70, 80, 90: expansion valve

[Document 1] Japanese Unexamined Patent Publication No. 2001-108308

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to expansion valves, and more particularly, to a thermal expansion valve for controlling a flow rate of a refrigerant supplied to an evaporator in accordance with a temperature and a pressure of an evaporator outlet by a refrigeration cycle of an automobile air conditioner.

In the refrigeration cycle of the air conditioner for automobiles, it is proposed to use carbon dioxide from an alternative Freon (HFC-134a) as a refrigerant used from environmental problems related to global warming. In a refrigeration cycle system using carbon dioxide as a refrigerant, internal heat exchangers are generally used to increase efficiency (see, for example, Document 1).

The internal heat exchanger is configured to perform heat exchange between the refrigerant flowing through the path from the gas cooler to the expansion valve that cools the high temperature and high pressure refrigerant compressed by the compressor and the refrigerant flowing through the path from the accumulator to the compressor. As a result, the gaseous refrigerant taken out from the accumulator is overheated by the refrigerant flowing in the path on the high pressure side of the internal heat exchanger and then transferred to the compressor. For this reason, since a refrigerant | coolant without moisture is sucked in a compressor, it can operate efficiently.

On the other hand, also in the refrigerating cycle using HFC-134a as a refrigerant | coolant, the system which introduce | transduced the internal heat exchanger is considered. Even in such a system, the efficiency is expected to be improved.

By the way, in a refrigeration cycle using HFC-134a as a refrigerant, a thermal expansion valve is generally used as an expansion valve. This thermostatic expansion valve controls the refrigerant at the outlet of the evaporator to have a predetermined degree of superheat. For this reason, in a refrigeration cycle in which an internal heat exchanger is provided to perform heat exchange between the refrigerant flowing through the path from the condenser to the expansion valve and the refrigerant flowing through the path from the evaporator to the compressor, the refrigerant that has already been overheated at the outlet of the evaporator is stored inside. Since the heat exchanger is overheated and then transferred to the compressor, especially when the refrigeration cycle is operated under a high refrigeration load, the temperature of the refrigerant compressed in the compressor becomes excessively high, and the lubricating oil of the compressor deteriorates at a high temperature. Had a problem.

The present invention has been made in view of such a point, and an object of the present invention is to provide an expansion valve which can cause the temperature of the refrigerant compressed in the compressor to be too high when the refrigeration load is high by a refrigeration cycle using an internal heat exchanger.

In the present invention, in order to solve the above problems, in the thermostatic expansion valve to control the flow rate of the refrigerant to be sent to the evaporator by sensing the temperature and pressure of the refrigerant exiting the evaporator, the high pressure refrigerant supplied with a high pressure refrigerant A bypass passage provided between an inlet or a low pressure refrigerant outlet for sending low pressure refrigerant to the evaporator and a refrigerant passage through which the refrigerant exiting the evaporator passes, allowing a high pressure liquid refrigerant or a low pressure gas-liquid mixed refrigerant to flow downstream of the temperature reduction portion; An expansion valve is provided, which is provided.

According to such an expansion valve, the refrigerant having high humidity is mixed with the refrigerant in an overheated state through the bypass passage. As a result, the refrigerant that is in the overheated state before entering the internal heat exchanger is cooled by the high humidity refrigerant and is overheated by the heat exchange in the internal heat exchanger. Therefore, the refrigerant supplied to the compressor at the time of high load is excessive. No overheating occurs and the temperature of the refrigerant compressed in the compressor is not too high.

EMBODIMENT OF THE INVENTION Hereinafter, the case where HFC-134a is used for a refrigerant | coolant and it is applied to the refrigeration cycle which has an internal heat exchanger is described in detail with reference to drawings for example.

1 is a system diagram showing a refrigeration cycle to which the expansion valve of the present invention is applied.

The refrigeration cycle includes a compressor (1) for compressing refrigerant, a condenser (2) for condensing the compressed refrigerant, an expansion valve (3) for throttling and expanding the cooled refrigerant, and an evaporator (4) for evaporating the expanded refrigerant. And an internal heat exchanger (5) which performs heat exchange between the refrigerant flowing from the condenser (2) to the expansion valve (3) and the refrigerant flowing from the evaporator (4) to the compressor (1) through the expansion valve (3). Equipped.

Expansion valve (3) has a temperature sensing section for sensing the temperature and pressure of the refrigerant exiting the evaporator (4), so that the temperature reduction portion to control the flow rate of the refrigerant to be sent to the evaporator (4) in accordance with the detected temperature and pressure A so-called thermostatic expansion valve. The expansion valve 3 according to the present invention has a bypass passage 3a (arrow shown by a solid line) or an evaporator 4 for flowing a high-pressure liquid refrigerant supplied from the internal heat exchanger 5 to the downstream side of the temperature reduction section. And a bypass passage 3b (arrow shown by broken lines) for flowing the low-pressure gas-liquid mixed refrigerant to be sent to the downstream side of the thermosensitive section. Next, the specific structure of this expansion valve 3 is demonstrated.

FIG. 2 is a central longitudinal sectional view showing the configuration of the expansion valve according to the first embodiment. FIG.

The expansion valve 10 according to the first embodiment includes a high-pressure refrigerant inlet 12 through which high-temperature and high-pressure liquid refrigerant is fed into the side of the body 11 from the internal heat exchanger 5, and the expansion valve 10. A low pressure refrigerant outlet 13 for sending the low temperature low pressure refrigerant throttled and expanded to the evaporator 4, a refrigerant passage inlet 14 receiving the refrigerant evaporated from the evaporator 4, and the expansion valve 10. The coolant passage outlet 15 which sends the coolant which passed through the internal heat exchanger 5 to the internal heat exchanger 5 is provided.

In the passage communicating from the high pressure refrigerant inlet 12 to the low pressure refrigerant outlet 13, the valve seat 16 is integrally formed with the body 11, and a ball-shaped valve body (upstream) of the valve seat 16 is formed. 17) are arranged. In the space in which the valve body 17 is accommodated, the valve body 17 is connected to the valve seat 16 via the valve body receiving portion 18 receiving the valve body 17 and the valve body receiving portion 18. The compression coil spring 19 which presses in the seating direction is arrange | positioned. The lower end of the drawing of the compression coil spring 19 can be supported by a spring receiving part 20, which is fitted to an adjustment screw 21 screwed to the lower end of the body 11. Lost The adjusting screw 21 has a function of adjusting the load of the compression coil spring 19 by adjusting the screw insertion amount into the body 11.

In addition, the expansion valve 10 is provided with a temperature sensing portion at the upper end of the body 11. The temperature sensing portion is formed by the upper housing 22, the lower housing 23, and the diaphragm 24 arranged to partition the space surrounded by them, and the disk 25 disposed on the lower surface of the diaphragm 24. Consists of.

Below the disk 25, the shaft 26 which transmits the displacement of the diaphragm 24 to the valve main body 17 is arrange | positioned. The upper portion of the shaft 26 is held by a holder 28 disposed across the refrigerant passage 27 communicating between the refrigerant passage inlet 14 and the refrigerant passage outlet 15. The holder 28 is provided with a compression coil spring 29 which gives a lateral load to the upper end of the shaft 26, and suppresses the vibration in the longitudinal direction of the shaft 26 against the pressure fluctuation of the high pressure refrigerant. .

The body 11 is provided with a bypass passage 30 through which the high pressure refrigerant supplied bypasses the expansion valve 10. The bypass passage 30 is formed between the high pressure refrigerant inlet 12 through which the high pressure liquid refrigerant is fed and the refrigerant passage 27, and a differential pressure control valve is inserted in the middle thereof. This differential pressure control valve presses the valve seat 31, the valve body 32 arrange | positioned so that connection and disconnection is possible by the downstream side facing the valve seat 31, and presses this valve body 32 to a closing direction. The compression coil spring 33 and the spring receiving part 34 which press-fits into the bypass passage 30 and support the compression coil spring 33 are included. The rod-shaped valve main body 32 is engraved with a plurality of communication grooves extending in the longitudinal direction on its outer circumference, and when the differential pressure control valve is opened, a high-pressure liquid refrigerant flows through the communication groove.

The expansion valve 10 having the above configuration senses the pressure and temperature of the refrigerant returned from the evaporator 4 to the refrigerant passage inlet 14, and when the temperature of the refrigerant is high or the pressure is low, the diaphragm 24 is closed. Displaced downward in the figure, the displacement is transmitted to the valve body 17 via the shaft 26 and moves the valve body 17 in the open direction, and conversely in the closed direction when the temperature is low or the pressure is high. The valve body 17 is moved to control the valve opening degree, and the flow rate of the refrigerant to be sent to the evaporator 4 is controlled. The expansion valve 10 senses the temperature of the refrigerant at the outlet of the evaporator 4 and controls the flow rate of the refrigerant sent to the evaporator 4, thereby entering the refrigerant passage inlet 14 from the evaporator 4. The coolant is controlled to have a predetermined degree of superheat.

On the other hand, the liquid refrigerant fed into the high pressure refrigerant inlet 12 from the internal heat exchanger 5 is mixed with the refrigerant in an overheated state passing through the refrigerant passage 27 via the bypass passage 30. The bypass amount of the liquid refrigerant is controlled according to the pressure difference between the pressure of the high pressure refrigerant inlet 12 and the pressure of the refrigerant passage 27. When the refrigeration load is small, since the pressure difference between the discharge pressure and the suction pressure of the compressor 1 is small, the pressure difference between the pressure of the high-pressure refrigerant inlet 12 and the pressure of the refrigerant passage 27 also decreases, and the bypass passage 30 The differential pressure control valve inserted into and closed is closed. In such a case, the liquid refrigerant does not flow directly into the downstream side of the thermosensitive section. This is because, when the refrigeration load is small, the temperature of the refrigerant compressed in the compressor 1 does not become very high.

When the refrigeration load is high, the pressure difference between the discharge pressure and the suction pressure of the compressor 1 increases, and the pressure difference between the pressure of the high-pressure refrigerant inlet 12 and the pressure of the refrigerant passage 27 also increases, so that the differential pressure control valve is When the pressure difference ratio reaches a predetermined value (for example, 1.3 MPa) or more, the pressure is released against the pressing force of the compression coil spring 33, and the liquid refrigerant flows downstream of the temperature reduction portion and is mixed with the refrigerant in an overheated state. As a result, the coolant in the overheated state is reduced to a coolant containing moisture. Such a refrigerant is heat-exchanged with the coolant of the low temperature from the condenser 2 by the internal heat exchanger 5, so that the refrigerant, evaporated and overheated and overheated, is sucked into the compressor 1. Therefore, since the temperature of the refrigerant sucked into the compressor 1 does not increase excessively, the temperature of the refrigerant compressed by the compressor 1 does not increase excessively, and the lubrication of the compressor 1 circulating in the refrigeration cycle with the refrigerant is eliminated. The thermal deterioration of the bow oil is eliminated.

3 is a central longitudinal sectional view showing a configuration of the expansion valve according to the second embodiment. In Fig. 3, the same components as those shown in Fig. 2 are denoted by the same reference numerals and the detailed description thereof will be omitted.

In the expansion valve 40 according to the second embodiment, the expansion valve 10 according to the first embodiment is inserted by inserting a differential pressure control valve into the bypass passage 30. The orifice 35 of a micro degree of opening is provided in this. According to the expansion valve 40 of this structure, the liquid refrigerant always flows through the bypass passage 30. Therefore, when the refrigeration load is small, the temperature of the refrigerant sent to the internal heat exchanger 5 may be too low, but the cost can be reduced compared to the expansion valve 10 according to the first embodiment including the differential pressure control valve. Can be.

4 is a central longitudinal cross-sectional view showing a configuration of the expansion valve according to the third embodiment. In Fig. 4, the same components as those shown in Fig. 2 are denoted by the same reference numerals and the detailed description thereof will be omitted.

In the expansion valve 50 according to the third embodiment, the expansion valve 10 according to the first embodiment forms a bypass passage 30 between the high pressure refrigerant inlet 12 and the refrigerant passage 27. On the other hand, it differs in that it is formed in the body 11 between the low pressure refrigerant | coolant outlet 13 and the refrigerant | coolant path | route 27. FIG.

The expansion valve 50 is inserted into the bypass passage 30 by inserting a differential pressure control valve. However, the differential pressure control valve is a spring of the compression coil spring 33 so as to open when the differential pressure control valve is, for example, 0.03 MPa or more. The load is set. As a result, when the refrigeration load is small, the flow rate of the refrigerant flowing through the evaporator 4 is small, so that the differential pressure between the inlet and the outlet of the evaporator 4 is also reduced, and the differential pressure is inserted into the bypass passage 30. The differential pressure before and after the differential pressure control valve is substantially the same, and the differential pressure control valve is closed. Thus, the high pressure liquid refrigerant exits the gap between the valve body 17 and the valve seat 16 so that the refrigerant of the gas-liquid mixture expanded at the low pressure refrigerant outlet 13 is all sent to the evaporator 4, There is no direct inflow to the downstream side of a thermosensitive part.

When the refrigeration load is high, since the flow rate of the refrigerant flowing through the evaporator 4 is large, the differential pressure between the inlet and the outlet of the evaporator 4 is large, that is, the differential pressure before and after the differential pressure control valve increases. When the differential pressure is higher than or equal to the predetermined value, the pressure is released against the pressing force of the compression coil spring 33, and the liquid refrigerant flows into the downstream side of the temperature reduction portion and is mixed with the refrigerant in an overheated state. As a result, the temperature of the refrigerant sucked into the compressor 1 does not increase excessively, the temperature of the refrigerant compressed by the compressor 1 does not increase too much, and the lubricating oil of the compressor 1 does not deteriorate thermally. .

5 is a central longitudinal sectional view showing a configuration of an expansion valve according to a fourth embodiment. In Fig. 5, the same components as those shown in Fig. 3 are denoted by the same reference numerals, and such detailed description is omitted.

In the expansion valve 60 according to the fourth embodiment, the orifice 35 is provided in the bypass passage 30 similarly to the expansion valve 40 according to the second embodiment. According to the expansion valve 40 of this configuration, the gas-liquid mixed refrigerant always flows through the bypass passage 30. As the gas-liquid mixed refrigerant is mixed into the refrigerant flowing in the refrigerant passage as described above, the temperature of the refrigerant sent to the internal heat exchanger 5 decreases, so that the temperature of the refrigerant compressed by the compressor 1 becomes excessively high when the refrigeration load is high. Disappear.

6 is a central longitudinal sectional view showing a configuration of the expansion valve according to the fifth embodiment. In Fig. 6, the same components as those shown in Fig. 2 are denoted by the same reference numerals, and such detailed description is omitted.

In the expansion valve 70 according to the fifth embodiment, the bypass passage 30 has a through hole formed in the body 11 so that the shaft 26 disposed between the temperature reduction portion and the valve body 17 is inserted therethrough. It consists of. In the bypass passage 30, the valve body 32 of the differential pressure control valve is arranged to retreat in the axial direction with the shaft 26 as a guide, and the compression coil spring 33 is provided with the valve body 32 and the holder 28. The valve main body 32 is urged in the direction which is arrange | positioned in between and seated on the valve seat 31 which consists of the step part in the bypass passage 30. As shown in FIG.

Compared with the expansion valve 50 according to the third embodiment shown in Fig. 4, the expansion valve 70 has only a different installation position of the bypass passage 30, Since the differential pressure control valve is opened when the differential pressure before and after the predetermined value is equal to or more than a predetermined value, the operation is performed to be exactly the same as the expansion valve 50.

In addition, although the opening part through which the refrigerant is supplied from the bypass passage 30 to the refrigerant passage 27 is provided at a position facing the temperature reduction portion of the refrigerant passage 27, the opening is separated from the bypass passage 30 through the differential pressure control valve. The low-temperature gas-liquid mixed refrigerant supplied to the refrigerant passage 27 is directly pressurized by the refrigerant from the evaporator 4 to the side of the refrigerant passage outlet 15, so that the temperature is not reduced by the temperature reduction portion, and is downstream of the temperature reduction portion. It mixes with the refrigerant | coolant returned from the evaporator 4 by this.

7 is a central longitudinal sectional view showing a configuration of an expansion valve according to a sixth embodiment. In Fig. 7, the same components as those shown in Fig. 3 are denoted by the same reference numerals and the detailed description thereof will be omitted.

The expansion valve 80 which concerns on this 6th Embodiment is comprised by the through-hole formed in the body 11 so that the bypass passage 30 may penetrate the shaft 26 arrange | positioned between the temperature-sensitive part and the valve main body 17. FIG. In the meantime, it has an orifice 35. According to this expansion valve 80, the structure which always mixes damp refrigerant with the superheated refrigerant supplied from the evaporator 4 using the differential pressure of the inlet and outlet of the evaporator 4 is the 4th implementation shown in FIG. Since it is substantially the same as the expansion valve 60 with respect to the form, this expansion valve 80 functions like the expansion valve 60.

8 is a central longitudinal sectional view showing a configuration of the expansion valve according to the seventh embodiment. In Fig. 8, the same or equivalent components as those shown in Fig. 4 are denoted by the same reference numerals, and such detailed description is omitted.

The expansion valve 90 which concerns on this 7th Embodiment is applied to the refrigeration cycle which employ | adopted the double pipe 36 for the piping of the compressor 1 and the condenser 2 side. The double tube 36 is configured such that the outer tube 36a and the inner tube 36b are arranged coaxially, and the refrigerant flowing through the outer tube 36a and the refrigerant flowing through the inner tube 36b are divided by the inner tube 36b. And the function of the internal heat exchanger 5.

The expansion valve 90 has a high pressure refrigerant inlet 12 through which a high temperature and high pressure liquid refrigerant is fed from the condenser 2 on the side of opening the valve body 17, and a compression coil downstream of the valve body 17. The spring 19 and the spring receiving part 20 are arrange | positioned. The bypass passage 30 is formed between the low temperature low pressure room in which the valve main body 17 is disposed, and the refrigerant passage 27 through which the refrigerant returned from the evaporator 4 passes. At the opening end of the bypass passage 30 to the refrigerant passage 27, a valve main body 32 is disposed, which is held by the shaft 26 and can move back and forth in the direction of opening and closing the bypass passage 30. The main body 32 is pressed by the compression coil spring 33 in the direction which seats on the valve seat 31, and comprises the differential pressure control valve.

The high temperature and high pressure liquid refrigerant fed into the high pressure refrigerant inlet 12 from the external pipe 36a of the double pipe 36 is axially expanded when passing through the gap between the valve seat 16 and the valve body 17 so that the low temperature low pressure refrigerant And is sent from the low pressure refrigerant outlet 13 to the evaporator 4. The refrigerant returned from the evaporator 4 can be supported by the refrigerant passage inlet 14 and is sent out from the refrigerant passage outlet 15 to the inner tube 36b of the double pipe 36 via the refrigerant passage 27. At this time, the temperature sensing unit senses the temperature and pressure of the refrigerant flowing through the refrigerant passage 27 and controls the flow rate of the refrigerant sent to the evaporator 4.

In addition, the differential pressure control valve provided in the bypass passage 30 senses the pressure difference between the pressure of the refrigerant of the low pressure refrigerant outlet 13 and the pressure of the refrigerant of the refrigerant passage 27, and thus the refrigerant passage 27 from the low pressure refrigerant outlet 13. The flow rate of the refrigerant to be bypassed by) is controlled. Although the opening portion through which the refrigerant is supplied from the bypass passage 30 to the refrigerant passage 27 is provided at a position facing the temperature reduction portion of the refrigerant passage 27, the refrigerant passage from the bypass passage 30 through the differential pressure control valve. The low-temperature gas-liquid mixed refrigerant supplied to (27) is condensed into the refrigerant passage outlet 15 by the refrigerant evaporated by the evaporator 4, so that the temperature is not reduced by the temperature reduction unit.

In the above embodiment, the case where an internal heat exchanger is applied to a refrigeration cycle in which HFC-134a is used as a refrigerant has been described, for example. However, the global warming coefficient is reduced, and thus it can be applied to a refrigeration cycle using refrigerants other than similar physical properties.

Since the expansion valve of the present invention is configured to allow a high humidity refrigerant to flow downstream of the temperature reducing portion by a bypass passage, when applied to a refrigeration cycle using an internal heat exchanger, the refrigerant supplied to the compressor through the heat exchanger can be cooled down. As a result, when the refrigeration load is high, the temperature of the refrigerant compressed by the compressor is not excessively high, and there is an advantage that the lubricating oil of the compressor is also prevented from being deteriorated in temperature.

Claims (8)

In the temperature expansion valve for controlling the flow rate of the refrigerant sent to the evaporator by sensing the temperature and pressure of the refrigerant exiting the evaporator, A high pressure liquid refrigerant or a low pressure gas-liquid mixed refrigerant is provided between the high pressure refrigerant inlet through which the high pressure refrigerant is supplied or the low pressure refrigerant outlet through which the low pressure refrigerant is sent to the evaporator and the refrigerant passage through which the refrigerant from the evaporator passes. And a bypass passage for flowing downstream. The expansion valve according to claim 1, wherein the bypass passage is an orifice penetrating through a body between the high pressure refrigerant inlet and the refrigerant passage. The expansion path according to claim 1, wherein the bypass passage has a differential pressure control valve which is opened in a passage formed through the body between the high pressure refrigerant inlet and the refrigerant passage to open when the differential pressure before and after the pressure exceeds a predetermined value. valve. The expansion valve according to claim 1, wherein the bypass passage is an orifice penetrating through the body between the low pressure refrigerant outlet and the refrigerant passage. 2. The bypass passage according to claim 1, characterized in that the bypass passage has a differential pressure control valve which is opened in a passage formed through the body between the low pressure refrigerant outlet and the refrigerant passage when the differential pressure before and after the pressure exceeds a predetermined value. Expansion valve. The expansion valve according to claim 1, wherein the bypass passage is a through hole formed in the body such that a shaft disposed between the temperature reduction portion and the valve body for controlling the flow rate of the refrigerant to the evaporator is inserted therethrough. The pressure difference between the front and the rear of the bypass passage is a predetermined value in a through hole formed in the body such that a shaft disposed between the temperature reduction portion and the valve body for controlling the flow rate of the refrigerant to the evaporator is inserted therethrough. The expansion valve which has a differential pressure control valve which opens when abnormal. The expansion valve according to claim 1, wherein the expansion valve is applied to a refrigeration cycle having an internal heat exchanger for performing heat exchange between the refrigerant leaving the condenser and the refrigerant sucked into the compressor.

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