JPH10252991A - Chlorofluorocarbon recovery machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chlorofluorocarbon recovering machine capable of performing the efficiency recovering work of the chlorofluorocarbon even in summer time by controlling the recovery flow rate of the chlorofluorocarbon according to the ambient temperature. SOLUTION: The recovery quantity (m) of the chlorofluorocarbon to be recovered from a refrigerating machine 1 is differentiated by a differentiating circuit 6 to obtain the process value Pv, and a set value Sv is obtained by a set value generation circuit 9 based on the ambient temperature θ detected by a temperature detector 8. The PI operation is performed to the difference between the process value Pv and the set value Sv by a chlorofluorocarbon flow rate control part 7 to obtain the operation quantity (n). The operation quantity (n) is transmitted to an operation part 5 as the protective operation quantity nL by a limiter 10, and the recovery flow rate of the chlorofluorocarbon is regulated by controlling a control valve 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chlorofluorocarbon recovery machine for recovering chlorofluorocarbon from equipment using fluorocarbon such as a refrigerator mounted on an aircraft.

[0002]

2. Description of the Related Art Some aircraft are equipped with a refrigerator for air conditioning inside the aircraft or for cooling electronic equipment. In such a refrigerator, it is necessary to discharge and remove Freon used as a refrigerant every time regular maintenance is performed. By the way, recently, in order to protect the global environment, chlorofluorocarbon discharged from a refrigerator is once collected and purified, and refilled into a refrigerator after maintenance.

FIG. 9 shows a conventional CFC recovery machine used for recovery of CFCs. The CFCs vaporized and discharged from the refrigerator 1 are sent to the CFC purifier 4a of the CFC recovery unit 4 via the stop valve 2 and the needle valve 21. The needle valve 21 is a valve for adjusting the flow rate of the chlorofluorocarbon gas sent to the chlorofluorocarbon purifying and compressing apparatus 4a by manual operation when the stop valve 2 is released.
Further, the chlorofluorocarbon purification and compression device 4a is a device for purifying, compressing and liquefying the chlorofluorocarbon sent from the refrigerator 1. Fluorocarbon used in the refrigerator 1 may be mixed with impurities such as moisture and air, and such moisture and air may cause corrosion or oxidation of the equipment. Therefore, the collected Freon is purified by the Freon purification / compression device 4a for reuse.

In the CFC recovery section 4, the CFC liquefied by the CFC purification / compression device 4a is sent to a collection cylinder 4c via a stop valve 4b and stored. The collecting cylinder 4c is placed on a measuring device 4d. The weighing device 4d is a detector that detects the recovery amount of Freon by measuring the weight of the recovery cylinder 4c,
The detected amount of Freon recovered here is sent to and displayed on the display 4e.

[0005] The refrigerator 1 performs maintenance after recovering Freon by the Freon recovery machine. Further, after the maintenance is completed, the fluorocarbon recovered in the recovery cylinder 4c is sequentially vaporized by using a pipeline bypassing the fluorocarbon purification and compression device 4a, and the stop valve 4b and the needle valve 2 are used.
Refrigerator 1 is refilled via 1 and stop valve 2.

If the flow rate of Freon discharged from the refrigerator 1 is too large during the recovery of Freon by the above-mentioned Freon recovery machine, the heat of vaporization taken when the liquid Freon is vaporized increases, and the inside of the refrigerator 1 is increased. However, since it is too cold, on the other hand, it takes an extremely long time to suppress the evaporation and exhaust all the chlorofluorocarbon. However, even if the flow rate is too small, the discharge time of the chlorofluorocarbon increases. Therefore, conventionally, by operating the needle valve 21, the flow rate of the chlorofluorocarbon has been adjusted so that the chlorofluorocarbon is discharged most efficiently.

[0007]

However, the flow rate at which the chlorofluorocarbon is discharged most efficiently varies depending on the ambient temperature at the time of recovery. That is, if the ambient temperature is low, such as in winter, the inside of the refrigerator 1 is also low temperature from the beginning,
It is necessary to vaporize the chlorofluorocarbon as slowly as possible. However, if the ambient temperature is high, such as in summer, even if the chlorofluorocarbon is vaporized somewhat rapidly, the temperature in the refrigerator 1 will not be too low. However, it is difficult for the conventional CFC recovery machine to adjust the optimal flow rate according to the ambient temperature by operating the needle valve 21. Therefore, the needle valve is set so that the optimal flow rate is obtained in advance when the ambient temperature is the lowest. 21 has to be set so that even during such a period, efficient and efficient CFC recovery can be performed.

For this reason, in the conventional CFC recovery machine, since the flow rate is set to be small in accordance with the time when the ambient temperature is low, the CFC must be recovered for an unnecessarily long time when the ambient temperature is high. In particular, there is a problem that the working efficiency is deteriorated particularly in summer and the like. This problem also occurs when the refrigerator 1 is refilled with the Freon recovered by the Freon recovery machine.

The present invention has been made in view of such circumstances, and by controlling the flow rate of chlorofluorocarbon in accordance with the ambient temperature, a chlorofluorocarbon collection machine capable of efficiently performing the collection of fluorocarbon even in summer or the like. It is intended to provide.

[0010]

In order to solve the above-mentioned problems, the invention of claim 1 detects a recovery flow rate of chlorofluorocarbon discharged from a device using chlorofluorocarbon, and determines the recovery flow rate according to the ambient temperature. By adjusting the recovery flow rate based on the comparison between the target flow rate and the recovery flow rate, the fluorocarbon can be recovered at the most efficient recovery flow rate according to the ambient temperature. Therefore, during a low ambient temperature period such as winter, the recovery flow rate is suppressed, so that CFCs are recovered at the same speed as in the past. In many cases, CFCs can be recovered at a higher speed than before. Also, in the case where the collected Freon is refilled into the equipment using the Freon, the filling rate of the Freon can be controlled in the same manner to increase the Freon filling rate during a period when the ambient temperature is high such as in summer.

The chlorofluorocarbon recovery machine according to the first aspect of the present invention may be configured to collect both chlorofluorocarbons and refill the collected fluorocarbons, or may perform only the collection of fluorocarbons or only the chlorofluorocarbon. . When refilling Freon, the collected Freon is liquefied and temporarily stored, and the stored Freon is vaporized and refilled. The flow rate adjusting means usually adjusts the flow rate of vaporized Freon, but may adjust the flow rate of Freon liquefied by collection or liquefied Freon used for filling. In addition, the flow rate detecting means,
The flow rate of the liquefied Freon may be detected, or the flow rate of the vaporized Freon may be detected.

According to a second aspect of the present invention, the weight of the liquefied chlorofluorocarbon stored by the recovery is detected, and the weight of the liquefied fluorocarbon is differentiated to detect the flow rate of the chlorofluorocarbon recovered / filled. When collecting CFCs, the weight increases according to the recovery flow rate, and when refilling CFCs, the weight decreases according to the charging flow rate. it can.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 to FIG. 6 show a first embodiment of the present invention. FIG. 1 is a block diagram showing the structure of a chlorofluorocarbon recovery machine, and FIG. FIG. 3 is a block diagram showing a configuration example of a differentiating circuit, FIG. 4 is a block diagram showing a configuration example of a set value generating circuit,
FIG. 5 is a block diagram showing a configuration example of a CFC flow control unit, and FIG. 6 is a block diagram showing a configuration example of a limiter. In addition,
Components having functions similar to those of the conventional example shown in FIG. 9 are denoted by the same reference numerals.

In this embodiment, a CFC recovery machine for collecting and refilling CFC will be described. In the first embodiment, a case where an analog controller is used will be described.

As shown in FIG. 1, the CFC vaporized and discharged from the refrigerator 1 is sent to a CFC purifying and compressing device 4a of a CFC recovery unit 4 through a stop valve 2 and a control valve 3. I have. When the stop valve 2 is released, the control valve 3 operates the operating unit 5 to operate the CFC purification / compression device 4a.
This is a valve in which the flow rate of the chlorofluorocarbon gas to be sent to is adjusted. The operation unit 5 adjusts the flow rate of the CFC gas by controlling, for example, a piezoelectric element of the control valve 3 in accordance with an electric signal of a protection operation amount nL described later. The control valve 3 and the operation unit 5 are not limited to such a piezoelectric type as long as they adjust the flow rate of chlorofluorocarbon, and may be any of a pneumatic type and a type that controls a solenoid valve by a pulse width control type. It may be of the type.

The CFC recovery unit 4 includes a CFC purification / compression unit 4a and a stop valve 4 having the same configuration as that of the conventional example shown in FIG.
b, a collecting cylinder 4c, a measuring device 4d, and a display 4e. However, from the display 4e, the recovered amount m of Freon detected by the measuring device 4d is output.

The Freon recovery amount m output from the measuring device 4d of the Freon recovery unit 4 is differentiated by a differentiating circuit 6 and sent to the Freon flow control unit 7 as a process value Pv. The collection amount m indicates the weight of fluorocarbon sequentially stored in the recovery cylinder 4c (which may include the weight of the recovery cylinder 4c) from time to time, and the recovery of the fluorocarbon flowing into the recovery cylinder 4c is performed. The flow rate is integrated. Therefore, the process value P obtained by differentiating the recovery amount m by the differentiation circuit 6
v indicates the flow rate of CFCs flowing into the collection cylinder 4c. That is, as shown in FIG.
Is a signal that monotonically increases with time, and the process value P
v is a signal indicating the change in the collection amount m. Also,
The recovery flow rate of Freon flowing into the recovery cylinder 4c is:
The flow rate substantially matches the flow rate of the Freon gas passing through the control valve 3. This differentiating circuit 6 can be configured by connecting a negative feedback circuit of an operational amplifier 6a to a capacitor C as shown in FIG. 3, for example. Here, all the resistors R have the same resistance value.

The chlorofluorocarbon recovery machine is provided with a temperature detector 8 for detecting the ambient temperature. The ambient temperature θ detected by the temperature detector 8 is used as the setting value generation circuit 9.
And sent to the temperature detector 8 as the set value Sv. The set value generation circuit 9 is a circuit that obtains a set value Sv by performing an operation of (θ−θ ₀ ) k + θ _{0 on} the ambient temperature θ.
θ ₀ is an initial set value of the ambient temperature, and k is a constant coefficient.
Then, the set flow rate Sv is used to set a recovery flow rate at which the chlorofluorocarbon can be recovered most efficiently at the actual ambient temperature θ. As shown in FIG. 4, for example, the set value generating circuit 9 can be configured by connecting a subtraction circuit 9b having a negative feedback circuit of an operational amplifier 9a and an adding circuit 9d having a negative feedback circuit of an operational amplifier 9c. Further, the subtraction circuit 9b multiplies the coefficient k by adjusting the variable resistor VR and changing the gain of the feedback circuit of the operational amplifier 9a. Here, all the resistors R have the same resistance value.

The CFC flow control unit 7 is a control unit that performs a proportional operation (P) and an integral operation (I) in the PID control, and performs a proportional operation and an integral operation on the difference between the process value Pv and the set value Sv. To obtain the operation amount n. Therefore, the CFC flow rate control unit 7 determines the process value P
The manipulated variable n is adjusted so that v becomes equal to the set value Sv. When the process value Pv matches the set value Sv, a constant manipulated variable n is output and this state is maintained. As shown in FIG. 5, for example, as shown in FIG. 5, the CFC flow rate control unit 7 supplies a subtraction circuit 7b of a negative feedback circuit of an operational amplifier 7a from a negative feedback circuit of a capacitor C of an operational amplifier 7c whose integration constant is determined by a capacitor CI and a variable resistor RI. And an integrating circuit 7d. Also, the subtraction circuit 7b
Performs a proportional operation by adjusting the variable resistor VR and changing the gain of the feedback circuit of the operational amplifier 7a. Here, all the resistors R have the same resistance value.

The manipulated variable n obtained by the CFC flow control unit 7 is converted via the limiter 10 into a protected manipulated variable nL. Normally, the limiter 10 outputs the manipulated variable n directly as the protected manipulated variable nL, and the manipulated variable n is set to the low limiter set value n0.
Low limiter set value n0 only when it becomes smaller than
Is output as the protection operation amount nL. The CFC purifier 4a of the CFC recovery section 4 may damage the compressor if the flow rate of CFC recovery becomes zero. Therefore, for safety, the limiter 10 guarantees the minimum value of the protection operation amount nL for safety. . As shown in FIG. 6, the limiter 10 inputs an operation amount n to a selection circuit 10a including two diodes D via a negative feedback circuit 10c of an operational amplifier 10b, and also inputs a negative feedback circuit 10e of an operational amplifier 10d. The low limiter set value n0 is input through the selector 10a, and the larger one is output from the selection circuit 10a as the protection operation amount nL. Also here,
All resistors R have the same resistance value.

The protection operation amount nL output from the limiter 10 is sent to the operation unit 5. And the control valve 3
The Freon discharged from the refrigerator 1 is passed at a flow rate corresponding to the protection operation amount nL. Therefore, this CFC recovery machine can adjust the flow rate of CFC to be recovered so as to match the set value Sv corresponding to the ambient temperature θ.

As described above, in the chlorofluorocarbon recovery machine of the first embodiment, when the ambient temperature θ is low, such as in winter, the set value Sv becomes a small value, and the recovery flow rate at the control valve 3 is suppressed. , CFCs will be collected slowly,
At a time when the ambient temperature θ is high, the set value Sv becomes a correspondingly large value, so that the flow rate of recovery at the control valve 3 is increased, and it is possible to recover Freon at high speed. Also, when refrigerating the refrigerator 1 with the CFCs collected in the collection cylinder 4c, the filling rate of the CFCs can be increased at a time when the ambient temperature θ is high by controlling the filling flow rate in the same manner. .

FIGS. 7 and 8 show a second embodiment of the present invention. FIG. 7 is a block diagram showing the configuration of a CFC recovery machine, and FIG. 8 is a flowchart for explaining the operation of a microcomputer. It is. In addition, the first shown in FIG.
Constituent members having functions similar to those of the embodiment are denoted by the same reference numerals, and description thereof is omitted.

The second embodiment describes a CFC recovery machine using a digital controller. In this CFC recovery machine, as shown in FIG. 7, the microcomputer 11 executes each operation of the differentiation circuit 6, the CFC flow control unit 7, the set value generation circuit 9 and the limiter 10 of the first embodiment. It is. Therefore, the recovery amount m output from the display 4e of the CFC recovery unit 4 and the temperature detector 8
Is detected by the A / D converter 12,
The digital signal is converted into a digital signal through the microcomputer 13 and input to the microcomputer 11. The microcomputer 1
The protection operation amount nL calculated and output in step 1 is converted into an analog signal via the D / A converter 14 and sent to the operation unit 5.

The operation of the microcomputer 11 is shown in FIG. First step (hereinafter referred to as "S")
Then, the amount m of CFC recovery is input from the display 4e (S
1) The process value Pv is obtained by differentiating the recovered amount m (S2). In this differential operation, the difference from the previously input recovery amount m may be obtained. Next, the ambient temperature θ is input from the temperature detector 8 (S3), and the set value S is calculated from the ambient temperature θ by the same calculation as the set value generation circuit 9 of the first embodiment.
v is obtained (S4). When the process value Pv and the set value Sv are obtained in this way, the manipulated variable n is obtained by the same proportional operation and integral operation as in the CFC flow control unit 7 of the first embodiment (S5). The operation amount n is set to a low limiter set value n.
0 (S6), and the larger one is the protection operation amount n
L is set (S7, S8), and this protection operation amount nL is output (S9). By repeating these processes at regular intervals, it is possible to adjust the flow rate of the Freon to be collected so as to match the set value Sv corresponding to the ambient temperature θ.

Therefore, the chlorofluorocarbon recovery machine of the second embodiment can also recover and refill fluorocarbon at a high speed when the ambient temperature θ is high, as in the first embodiment.

In the above embodiment, the process value Pv, which is the recovery flow rate or the filling flow rate, is obtained by differentiating the recovery amount m of the fluorocarbon, but the flow rate of the vaporized fluorocarbon or the liquefied fluorocarbon is directly detected. The recovery / filling flow rate may be obtained. In the above embodiment,
The operation amount n is obtained by performing a proportional operation and an integral operation on the difference between the process value Pv and the set value Sv. However, the operation amount n is not necessarily limited to this. It may be obtained. However, in the CFC recovery machine, it is not necessary to perform a differential operation because there is no need to increase the feedback response.

[0029]

As is clear from the above description, according to the chlorofluorocarbon recovery machine of the present invention, the recovery flow rate and the filling flow rate are increased during periods of high ambient temperature, such as in summer, so that the chlorofluorocarbon recovery can be performed at a higher speed than before. Can be recovered and refilled. Further, if the weight of the chlorofluorocarbon is detected and differentiated, the recovery / filling flow rate can be easily detected without using a complicated device for directly detecting the flow rate of the chlorofluorocarbon.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the present invention,
It is a block diagram which shows the structure of a CFC collection machine.

FIG. 2 shows a first embodiment of the present invention,
It is a figure which shows the relationship between the collection amount m of Freon and the process value Pv.

FIG. 3 shows a first embodiment of the present invention,
FIG. 3 is a block diagram illustrating a configuration example of a differentiating circuit.

FIG. 4 shows a first embodiment of the present invention,
FIG. 3 is a block diagram illustrating a configuration example of a setting value generation circuit.

FIG. 5 shows a first embodiment of the present invention,
It is a block diagram showing an example of composition of a CFC flow control part.

FIG. 6 illustrates a first embodiment of the present invention,
FIG. 3 is a block diagram illustrating a configuration example of a limiter.

FIG. 7 illustrates a second embodiment of the present invention,
It is a block diagram which shows the structure of a CFC collection machine.

FIG. 8 shows a second embodiment of the present invention,
5 is a flowchart for explaining the operation of the microcomputer.

FIG. 9 shows a conventional example, and is a block diagram showing a configuration of a CFC recovery machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Refrigerator 3 Control valve 4 CFC collection part 4c Collection cylinder 4d Meter 5 Operation part 6 Differentiation circuit 7 CFC flow control part 8 Temperature detector 9 Set value generation circuit 11 Microcomputer

Claims (2)

[Claims] An apparatus for recovering and / or filling chlorofluorocarbon into a chlorofluorocarbon collection apparatus for recovering chlorofluorocarbon and / or vaporizing liquefied chlorofluorocarbon and charging the chlorofluorocarbon with the fluorocarbon. Adjusting means; flow rate detecting means for detecting the flow rate of CFC recovery / filling; ambient temperature detecting means for detecting the ambient temperature; a target flow rate set according to the ambient temperature detected by the ambient temperature detecting means; A chlorofluorocarbon recovery machine comprising: chlorofluorocarbon flow control means for controlling the recovery / filling flow rate adjusted by the flow rate adjusting means based on a comparison with the recovery / filling flow rate detected by the detection means. 2. A weighing means for detecting the weight of Freon stored by liquefaction by collection, wherein the Freon flow rate detecting means comprises:
2. The CFC recovery machine according to claim 1, further comprising a differentiator for detecting the flow rate of the CFC recovery / filling by differentiating the weight measured by the metering means.