JP2004190894A - Refrigerant filling method of refrigeration cycle and refrigerant filling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerant filling method and a refrigerant filling device capable of additionally filling the refrigerant at an appropriate amount without discharging the refrigerant. <P>SOLUTION: The device is provided with a refrigerant storage container 6 storing the refrigerant, a supply path K supplying the refrigerant from the refrigerant storage container 6 to a refrigeration cycle R, and a volume variable part 5 provided by branching from the middle of the supply path K. When the outside air temperature Ta is lower than the critical temperature Tc of the refrigerant, the refrigerant in the volume variable part 5 is sucked into the refrigeration cycle R after the refrigerant is additionally filled to the refrigerant pressure Pn1 at the time when the refrigerant is filled to the appropriate amount by adding the volume V0 in the volume variable part 5 to the refrigeration cycle R. The refrigerant can be additionally filled at the appropriate amount without discharging the refrigerant. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention includes a compressor, a condenser, a decompressor and an evaporator relates refrigerant charging method and refrigerant charging apparatus for adding fill the refrigerant in the refrigerating cycle annularly connecting, in particular, low critical temperature CO ₂ And a refrigerant charging method.
[0002]
[Prior art]
Conventionally, for a Freon refrigerant or the like having a high critical temperature, an appropriate amount of additional charge can be performed while checking the gas-liquid state of the refrigerant from the sight glass of the receiver. On the other hand, in the case of a CO ₂ refrigerant or the like having a low critical temperature, the refrigerant is in a single-phase gas state, so that it is not possible to additionally charge an appropriate amount while visually checking the refrigerant. Therefore, when the refrigerant is additionally charged in a refrigeration cycle using a CO ₂ refrigerant or the like, the refrigerant in the refrigeration cycle is actually discharged once, and then the refrigerant is refilled by a regular amount while measuring the weight. ing.
[0003]
[Problems to be solved by the invention]
However, there are the following problems in discharging and refilling the refrigerant in the refrigeration cycle.
-When the refrigerant is discharged, the compressor oil is also discharged at the same time, so there is a possibility that insufficient lubrication of the compressor due to lack of compressor oil after refilling.
・ The released compressor oil may be in the form of a mist and inhaled by the human body.
-In order to measure the regular filling amount, it is necessary to measure the weight of each refrigerant container such as a cylinder, and to weigh with sufficient accuracy to detect the filled amount.
[0004]
The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a refrigerant charging method and a refrigerant charging device capable of additionally charging an appropriate amount without discharging the refrigerant. is there.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the technical means described in claims 1 to 5 is adopted. That is, according to the first aspect of the present invention, a refrigeration system in which a refrigerant compressor (10), a condenser (11), a pressure reducing device (12), and an evaporator (13) are sequentially connected in a ring by a refrigerant pipe (14). A cycle (R), a refrigerant storage means (6) storing the refrigerant, a supply path (K) for supplying the refrigerant from the refrigerant storage means (6) to the refrigeration cycle (R), and a supply path (K). A variable volume section (5) branching from the middle, and a refrigerant charging method for additionally charging the refrigerant to the refrigeration cycle (R).
When the outside air temperature (Ta) is lower than the critical temperature (Tc) of the refrigerant, the refrigerant pressure (Pn0) when the appropriate amount of refrigerant is charged by adding the volume (V0) of the variable volume section (5) to the refrigeration cycle (R). ), The refrigerant in the variable volume section (5) is sucked into the refrigeration cycle (R).
[0006]
According to the second aspect of the present invention, a refrigeration system in which a refrigerant compressor (10), a condenser (11), a pressure reducing device (12), and an evaporator (13) are connected in order in a refrigerant pipe (14). A refrigerant charging method and a refrigerant charging device for additionally charging a refrigerant to the cycle (R) include a refrigerant storage means (6) storing the refrigerant, and a refrigerant from the refrigerant storage means (6) to the refrigeration cycle (R). A supply path (K) for supply, and a variable volume section (5) branched from the middle of the supply path (K),
When the outside air temperature (Ta) is lower than the critical temperature (Tc) of the refrigerant, the refrigerant pressure (Pn0) when the appropriate amount of refrigerant is charged by adding the volume (V0) of the variable volume section (5) to the refrigeration cycle (R). ), The refrigerant in the variable volume section (5) is sucked into the refrigeration cycle (R).
[0007]
By these means, it is possible to additionally charge the refrigerant to an appropriate amount without discharging the refrigerant (only replenishment is required). In addition, since no refrigerant is released, there is no possibility that the compressor oil will be released to cause poor lubrication of the compressor or adversely affect the human body. Can also be shortened. In addition, an appropriate filling amount can be measured only by using a conventional pressure gauge.
[0008]
According to the third aspect of the present invention, the volume (V0) of the variable-volume section (5) can be set such that the volume (V0) of the variable-volume section (5) can be reduced even if the outside air temperature (Ta) is lower than the critical temperature (Tc) of the refrigerant. V0) is added to the volume (V0) at which the refrigerant in the refrigeration cycle (R) becomes a single-phase gas state. Thereby, even if the ambient temperature (outside air temperature) at the time of performing the refrigerant charging operation is various, the refrigerant charging operation can be performed by aligning the refrigerant with the single-phase state of the gas.
[0009]
The invention according to claim 4 is characterized in that the variable volume section (5) is constituted by a free piston (5a). Thus, the volume of the refrigeration cycle (R) can be easily increased by the residual pressure in the refrigeration cycle (R), and the volume easily increased by suctioning on the refrigeration cycle (R) side can be made zero. Can be.
[0010]
The invention according to claim 5 is characterized in that the refrigerant is a refrigerant having a lower critical temperature (Tc) than Freon gas. This means that the present invention is suitable for a refrigerant charging method and a refrigerant charging apparatus when additionally charging a refrigerant such as CO ₂ which has a lower critical temperature (Tc) than a conventional general fluorocarbon gas and tends to be in a single-phase gas state. by. In addition, the code | symbol in the parenthesis of each said means is an example which shows the correspondence with the concrete means described in embodiment mentioned later.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1A is a schematic diagram illustrating a configuration of a refrigerant charging device 100 according to an embodiment of the present invention, and FIG. 1B is an explanatory diagram of a volume variable unit 5 when the refrigerant is changed from two phases to a single phase. (C) is an explanatory view of the volume variable section 5 during refrigerant suction. FIG. 2 is a schematic diagram showing a schematic configuration of the refrigeration cycle R.
[0012]
In the present embodiment, a configuration and a refrigerant charging method of a refrigerant charging device when a refrigerant is additionally charged into a refrigeration cycle R of a vehicle air conditioner using a CO ₂ refrigerant will be described. First, as shown in FIG. 2, a refrigeration cycle R of a vehicle includes a refrigerant compressor (compressor) 10, a condenser (condenser) 11, an expansion valve (decompression device) 12, an evaporator (evaporator) 13, and an accumulator 15. CO ₂ having a low critical temperature is used as a refrigerant.
[0013]
The compressor 10 is driven by a vehicle driving engine (not shown) or a built-in electric motor, and compresses and discharges the refrigerant sucked from the accumulator 15 to a critical pressure or higher under general use conditions. The condenser 11 exchanges heat between the high-pressure gas refrigerant discharged from the compressor 10 and external air (hereinafter, “outside air”) blown by the blower 11a, and includes a refrigerant passage through which the refrigerant flows and an air passage through which the outside air flows. It is configured so that the flow direction of the refrigerant and the flow direction of the air are orthogonal.
[0014]
However, since the CO ₂ refrigerant flowing into the condenser 11 is pressurized to a critical pressure or higher by the compressor 10, the CO ₂ refrigerant does not condense even if heat is radiated by the condenser 11. The expansion valve 12 is a pressure reducing device that reduces the pressure of the refrigerant flowing out of the condenser 11 in accordance with the valve opening. The valve opening is electrically controlled by a control device (not shown).
[0015]
The evaporator 13 evaporates the refrigerant decompressed by the expansion valve 12 by heat exchange with the outside air or the vehicle interior air blown by the blower 13a. The accumulator 15 separates the refrigerant evaporated by the evaporator 13 into gas and liquid, stores the liquid refrigerant, causes only the gas-phase refrigerant to be sucked into the compressor 10, and stores the surplus refrigerant during the cycle.
[0016]
Next, a configuration and a refrigerant charging method of the refrigerant charging device 100 which is a main part of the present invention will be described. The refrigerant charging device 100 is provided with a built-in or connectable CO ₂ cylinder (refrigerant storage means) 6 that stores the refrigerant, and supplies the CO ₂ cylinder 6 and the refrigerant supplied to the refrigeration cycle R from the CO ₂ cylinder 6. Road K. The supply path K is provided with a valve 1 for interrupting the supply of the refrigerant.
[0017]
Further, a variable volume section 5 is provided which branches off in the middle of the supply path K. The volume variable section 5 is a pressure tank, and has a built-in free piston 5a for varying the volume (see (b)). The free piston 5a has a structure in which the free piston 5a slides freely by the pressure difference between both sides while maintaining the seal with the O-ring 5b.
[0018]
A valve 2 for interrupting communication with the refrigeration cycle R is provided on one of the variable volume units 5. The other of the variable volume section 5 is provided with a valve 3 that opens and closes when the internal gas is released to the outside, and a valve 4 for interrupting communication with the CO ₂ cylinder 6. 100a is a joint for connecting to the refrigeration cycle R side.
[0019]
In the connection portion on the refrigeration cycle R side, a low-pressure side service valve 14a is disposed in a refrigerant pipe 14 between the evaporator 13 and the accumulator 15 (see FIG. 2). Incidentally, 14b is a high-pressure side service valve. Then, the refrigeration cycle R and the refrigerant charging device 100 are connected by the gauge manifold 7 (see FIG. 1). The gauge manifold 7 is an instrument used for checking the operation pressure of the refrigeration cycle, evacuation and charging the refrigerant.
[0020]
Specifically, the low pressure charging hose 7a is connected to the low pressure side service valve 14a, the high pressure charging hose 7b is connected to the high pressure side service valve 14b, and the center charging hose 7c is connected to the joint 100a of the refrigerant charging device 100. By the way, at this time, the low pressure valve 7d and the high pressure valve 7e of the gauge manifold 7 and the valves 1 to 4 of the refrigerant charging device 100 are all closed, and when the refrigerant is charged, the low pressure valve 7d of the gauge manifold 7 is opened to open the refrigeration cycle R and the refrigerant. The communication with the filling device 100 is performed.
[0021]
Next, a procedure for additionally charging the refrigeration cycle R with the CO ₂ refrigerant from the CO ₂ cylinder 6 will be described with reference to the flowchart of FIG. FIG. 3 is a flowchart showing the operation of the refrigerant charging apparatus 100 according to the present invention when additional refrigerant is charged. First, as necessary data before performing the refrigerant charging operation, the normal refrigerant charging amount Gn and the internal volume Vin of the refrigeration cycle R are examined. The refrigerant density γg is calculated.
[0022]
[Formula 1]
γg = Gn / Vin
Next, the outside air temperature Ta is read as the ambient temperature when the refrigerant charging operation is performed in step S1. Then, in step S2, it is determined whether or not the outside air temperature Ta is higher than the critical temperature Tc of the refrigerant. If the determination is YES that the outside air temperature Ta is higher than the critical temperature Tc, the process proceeds to step S3 to open the valve 1 and supply the refrigerant. The fact that the outside air temperature Ta is higher than the critical temperature Tc of the refrigerant means that the refrigerant in the refrigeration cycle R is in a single-phase gas state, and thus the refrigerant pressure Pn at the time of charging the appropriate refrigerant amount is derived from the following equation (2).
[0023]
[Formula 2]
Pn = Pn (γg, Ta)
If the pressure P of the refrigeration cycle detected by the gauge of the gauge manifold 7 has not reached Pn in step S4 and the determination result is NO, the refrigerant is additionally charged in step S5, and the refrigeration cycle is determined in step S4. When the pressure P reaches Pn and the determination result is YES, the process proceeds to step S6, the valve 1 is closed, and the additional charging of the refrigerant is completed.
[0024]
Next, if the outside air temperature Ta is lower than the critical temperature Tc and the determination in step S2 is NO, the process proceeds to step S7, and the valves 2.3 are opened. The fact that the outside air temperature Ta is lower than the critical temperature Tc of the refrigerant means that the refrigerant in the refrigeration cycle R is in a gas-liquid two-phase state, so that an appropriate amount cannot be obtained by the above means.
[0025]
Therefore, the valves 2 and 3 are opened to apply the residual pressure in the refrigeration cycle R to the variable volume section 5 to move the free piston 5a, and to increase the volume V0 of the variable volume section 5 to the internal volume Vin of the refrigeration cycle R to increase the volume. Then, the refrigerant in the refrigeration cycle R is brought into a single-phase gas state. Incidentally, the inside of the variable volume section 5 is in the state of FIG.
[0026]
The refrigerant density γg0 when the regular refrigerant filling amount Gn is charged in a state where the volume is increased is derived from the following equation (3). In addition, since the gas is in a single-phase state, the refrigerant pressure Pn0 at the time of filling the appropriate refrigerant amount is calculated by the following Expression 4.
[0027]
(Equation 3)
γg0 = Gn / (Vin + V0)
[0028]
(Equation 4)
Pn0 = Pn0 (γg0, Ta)
Then, in step S8, the escape valve 3 is closed and the valve 1 is opened to supply the refrigerant. If the pressure P of the refrigeration cycle detected by the gauge of the gauge manifold 7 has not reached Pn0 in step S9 and the determination result is NO, the refrigerant is additionally charged in step S10, and the pressure of the refrigeration cycle is determined in step S9. When P reaches Pn0 and the determination result is YES, the process proceeds to step S11.
[0029]
In step S11, the valve 1 is closed to stop the supply of the refrigerant, and the valve 4 is opened to apply the pressure of the CO ₂ cylinder 6 so that the free piston 5a moves to the valve 2 side. Next, in step S12, the compressor 10 is driven to suck the refrigerant in the variable volume section 5 into the refrigeration cycle R. Incidentally, at this time, the inside of the variable volume unit 5 is in the state shown in FIG. After the refrigerant is sucked, the valves 2 and 4 are closed in step S13, and the additional charging of the refrigerant is completed.
[0030]
Next, features of the present embodiment will be described. First, a refrigerant storage means 6 such as a CO ₂ cylinder storing a refrigerant, a supply path K for supplying the refrigerant from the refrigerant storage means 6 to the refrigeration cycle R, and a branch provided from the middle of the supply path K are provided. When the outside air temperature Ta is lower than the critical temperature Tc of the refrigerant, the volume V0 of the variable volume section 5 is added to the refrigeration cycle R, and the refrigerant pressure Pn0 when the refrigerant is filled with an appropriate amount is added. After filling, the refrigerant in the variable volume section 5 is sucked into the refrigeration cycle R.
[0031]
As a result, the refrigerant can be additionally charged to an appropriate amount without discharging the refrigerant (only replenishment is required). In addition, since no refrigerant is released, there is no possibility that the compressor oil will be released to cause poor lubrication of the compressor or adversely affect the human body. Can also be shortened. In addition, an appropriate filling amount can be measured only by using a conventional pressure gauge.
[0032]
In addition, even if the outside air temperature Ta is lower than the critical temperature Tc of the refrigerant, the volume V0 of the variable volume unit 5 is changed to the single phase state of the gas in the refrigeration cycle R by adding the volume V0 of the variable volume unit 5. Volume V0. Thereby, even if the ambient temperature (outside air temperature) at the time of performing the refrigerant charging operation is various, the refrigerant charging operation can be performed by aligning the refrigerant with the single-phase state of the gas.
[0033]
Further, the volume variable section 5 is constituted by a free piston 5a. Accordingly, the volume of the refrigeration cycle R can be easily increased by the residual pressure in the refrigeration cycle R, and the increased volume can be easily reduced to zero by suction on the refrigeration cycle R side.
[0034]
The refrigerant is a refrigerant having a lower critical temperature Tc than Freon gas, such as CO ₂ . This is because the present invention is suitable for a refrigerant charging method and a refrigerant charging apparatus when additionally charging a refrigerant such as CO _2, which has a lower critical temperature Tc than a conventional general fluorocarbon gas and tends to be in a single-phase state of the gas.
[0035]
(Other embodiments)
In the above-described embodiment, the refrigerant charging method and the refrigerant charging device of the present invention are applied to the additional charging of the refrigerant to the vehicle air conditioner. However, the present invention is not limited to this. The present invention may be applied to additional charging of a refrigerant in the entire refrigeration cycle using a refrigerant such as a water heater or a water heater. Further, the refrigerant is not limited to CO ₂ , and may be applied to refrigerants such as ethylene, ethane, and nitrogen oxide as long as they have a low critical temperature.
[Brief description of the drawings]
FIG. 1A is a schematic diagram showing a configuration of a refrigerant charging device according to an embodiment of the present invention, FIG. 1B is an explanatory diagram of a volume variable portion when a refrigerant is changed from two phases to a single phase, (c) is an explanatory diagram of the volume variable section during refrigerant suction.
FIG. 2 is a schematic diagram showing a schematic configuration of a refrigeration cycle.
FIG. 3 is a flowchart showing an operation at the time of additional refrigerant charging in the refrigerant charging apparatus of the present invention.
[Explanation of symbols]
5 Variable volume section 5a Free piston 6 CO ₂ cylinder (refrigerant storage means)
10 Compressor
11 Condenser (condenser)
12 Expansion valve (pressure reducing device)
13. Evaporator (evaporator)
14 Refrigerant pipe K Supply path Pn0 Refrigerant pressure R Refrigeration cycle Ta Outside air temperature Tc Critical temperature V0 Volume in variable volume section

Claims (5)

A refrigeration cycle (R) in which a refrigerant compressor (10), a condenser (11), a pressure reducing device (12), and an evaporator (13) are sequentially connected in an annular manner by a refrigerant pipe (14);
Refrigerant storage means (6) storing refrigerant;
A supply path (K) for supplying a refrigerant from the refrigerant storage means (6) to the refrigeration cycle (R);
A method for charging a refrigerant when a refrigerant is additionally charged into the refrigeration cycle (R) by providing a volume variable portion (5) branched from the middle of the supply path (K).
When the outside air temperature (Ta) is lower than the critical temperature (Tc) of the refrigerant, the refrigerant pressure at the time when the appropriate amount of refrigerant is charged by adding the volume (V0) of the variable volume section (5) to the refrigeration cycle (R). A refrigerant charging method for a refrigeration cycle, characterized in that the refrigerant in the variable volume section (5) is sucked into the refrigeration cycle (R) after additional charging to (Pn0). When the refrigerant is additionally charged into a refrigeration cycle (R) in which a refrigerant compressor (10), a condenser (11), a pressure reducing device (12), and an evaporator (13) are sequentially connected in an annular manner by a refrigerant pipe (14). Refrigerant charging device,
Refrigerant storage means (6) storing refrigerant;
A supply path (K) for supplying a refrigerant from the refrigerant storage means (6) to the refrigeration cycle (R);
A variable volume section (5) provided by branching from the middle of the supply path (K);
When the outside air temperature (Ta) is lower than the critical temperature (Tc) of the refrigerant, the refrigerant pressure at the time when the appropriate amount of refrigerant is charged by adding the volume (V0) of the variable volume section (5) to the refrigeration cycle (R). The refrigerant charging device for a refrigeration cycle, wherein the refrigerant in the variable volume section (5) is sucked into the refrigeration cycle (R) after additional charging to (Pn0). The volume (V0) of the variable volume section (5) is increased by adding the volume (V0) of the variable volume section (5) even when the outside air temperature (Ta) is lower than the critical temperature (Tc) of the refrigerant. The refrigerant charging device for a refrigeration cycle according to claim 2, wherein the refrigerant in the cycle (R) has a volume (V0) at which a gas is in a single-phase state. The refrigerant charging device for a refrigeration cycle according to claim 2 or 3, wherein the variable volume portion (5) is constituted by a free piston (5a). The refrigerant charging device for a refrigeration cycle according to claim 2, wherein the refrigerant is a refrigerant having a lower critical temperature (Tc) than Freon gas. 5.

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