JPS6352340B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention detects phase changes of refrigerant in a refrigerant cycle, such as gas or liquid, purely electronically, and obtains a signal to control a compressor, blower, or refrigerant control solenoid valve. This relates to refrigerant state detection.

Figure 1 is a diagram showing how a conventional refrigerant condition detector is installed in a refrigerant cycle (only the main parts are shown).
1 is a compressor, 2 is a suction pipe, 3 is a flange, 4 is a refrigerant state detector, 4e, 4f are electrode extraction terminals, 1
5 is a suction strainer.

FIG. 2 is a configuration diagram showing a conventional refrigerant state detector 4, in which 4a is a metal outer cylinder, 4b is a metal inner cylinder,
4c is a mounting flange, 4g is an insulating seal, and 4d is a support rod.

In the refrigerant condition detector 4 shown in FIG. 2, a metal outer cylinder 4a and an inner cylinder 4b form a double pipe, and the capacitance between electrode lead terminals 4e and 4f changes due to the dielectric material between them. do. For example, in refrigerant R-22, the dielectric constant of refrigerant gas is 1.03, while that of refrigerant liquid is 6.6.
There is a difference of more than 6 times. In other words, in the case of a mixture of gas and liquid, it can be treated as a single dielectric material having a dielectric constant between 1.03 and 6.6, depending on the volume ratio of the space between the outer cylinder 4a and the inner cylinder 4b.

The phase change state of the refrigerant, that is, the ratio of gas/liquid mixture, is continuously detected as a change in capacitance between the electrode lead terminals 4e and 4f, and the signal obtained from this is used to control the compressor, blower, or refrigerant. This system controls the solenoid valves for stable and highly reliable operation.

However, in the ones in Figures 1 and 2,
When installing it into an existing refrigerant cycle, etc., it was necessary to pay close attention to the processing of the suction pipe 2 (flange attachment) and the leakage of refrigerant gas after installation. Furthermore, although the electrode lead terminals 4e and 4f protrude to the outside, care must be taken to ensure that the structure maintains strength so that it will not be damaged by mechanical shock during work (which may lead to gas leakage). Ta.

This invention was made to eliminate the above-mentioned drawbacks, and focuses on the suction strainer 15 attached to the compressor main body 1, and attempts to add a refrigerant state detection function to the suction strainer 15 in addition to its function as a strainer. It is something.

FIG. 3 is a diagram showing how the refrigerant condition detector 5 according to the present invention is installed. 1 is a compressor main body, 2 is a suction pipe, and 3 is a removable flange, into which the refrigerant state detector 5 is inserted when being installed or removed.

FIGS. 4a and 4b are structural diagrams showing one embodiment of the refrigerant state detector of the present invention, and FIG. 4b is a sectional view taken along the line bb--b of FIG. 4a. 5a is a cylindrical filter paper folded into a bellows shape, 5b and 5c are porous metal plates such as wire mesh provided on the outside and inside thereof, 5p is a reinforcing ring, and 5d is an end plate having a threaded part for installation. ,
5e is the other end plate, 5i and 5j are plastic spacers, 5g and 5f are terminals, 5k is a lead wire, and 5h is a glass seal. The end plates 5e, 5d and the outer porous metal plate 5b are crimped together while maintaining conductivity.

To explain the operation in FIG. 4, arrows indicate the flow of refrigerant, and the refrigerant is sucked in from the end plate 5d, passes through the porous inner metal plate 5c, the filter paper 5a, and the porous outer metal plate 5b, and passes through the strainer 5. It passes. Both porous metal plates 5b and 5c form a capacitor, and a change in dielectric constant due to a phase change of the refrigerant interposed therebetween can be extracted as a change in capacitance between terminals 5g and 5f.

5 and 6 are diagrams showing the main structure of another embodiment of the refrigerant detector 5. In FIG.
A porous metal plate such as a wire mesh is separately provided inside the inner metal plate 5c and is positioned through a plastic ring 5n. In FIG. 6, another porous metal plate 5l is provided outside the outer metal plate 5b and positioned via a plastic ring 5o.

FIG. 5 shows an example in which a capacitor is formed between an inner porous metal plate 5c and a porous metal plate 5m provided inside thereof via a plastic ring 5n. Since the distance between both porous metal plates can be made close, a large capacitance can be obtained, and the influence of stray capacitance is small, and since the biporous electrodes that serve as electrodes are not exposed to the outside, it is resistant to electrical noise and is stable. This shows the behavior. Capacitance is obtained between terminals 5f and 5g.

FIG. 6 shows an example of a structure in which a capacitor is also formed between the outer porous metal plate 5b and a porous metal plate 51 provided further outside thereof to further increase the capacitance. Capacitance is obtained from terminals 5g and 5f.

FIG. 7 is a system diagram showing an example of refrigerant cycle control using the refrigerant state detector of the present invention. 2
1 is an evaporator, 22 is a condenser, 23 and 34 are blowers, 25 is an expansion valve, 26 is an accumulator, 27
28 is a central control unit, 29 to 31 and 35 are interface circuits, 32 is a temperature sensor, and 33 is a resistance to voltage (or current or frequency) conversion circuit. ,
34 is a temperature setting circuit.

The signal caught by the refrigerant condition detector 5 is taken into the central control unit from F, and according to the previously programmed control algorithm, the compressor 1, blowers 23 and 2 are operated in a direction that reduces the detected capacitance.
4. Output from G, A, B and C to control the expansion valve 25.

In the configuration examples shown in Figs. 5 and 6, the distance between the electrodes can be shortened without increasing pressure loss (because the porous metal plates are adjacent to each other), and the capacitance can be increased, so the stray capacitance can be reduced. Can remove city influence. In particular, in FIG. 5, the electrode for detecting changes in capacitance is not exposed to the outside, so it is resistant to electrical noise.

The refrigerant condition detector 5 controls the capacity of the compressor 1, controls the blowers 23 and 24, or controls the expansion valve 25 to reduce the amount of liquid returning to the suction pipe 2 of the compressor 1. It becomes possible to reduce the capacity and ultimately eliminate it.

As described above, in the present invention, since the suction strainer is provided with the refrigerant state detection ability, installation within the refrigerant cycle is simplified.

Furthermore, in the present invention, the terminal lead-out portion, which is the weakest point in terms of strength, is provided inside the compressor body, so that the resistance against unexpected mechanical impact is increased.

[Brief explanation of the drawing]

Figure 1 is a diagram showing how it is installed in the refrigerant cycle;
FIG. 2 is a structural diagram showing a conventional refrigerant state detector, FIG. 3 is a diagram showing a state in which the refrigerant state detector of the present invention is installed, and FIG. 4a is a structural diagram showing an embodiment of the present invention. FIG. 4b is a sectional view taken along the line b-b of FIG. 4a, FIGS. 5 and 6 are diagrams showing other embodiments of the present invention, and FIG. 7 is a control system diagram in the refrigerant cycle. . In the figure, 1 is a compressor, 2 is a suction pipe, 3 is a flange, 4 and 5 are refrigerant state detectors, 4a is a metal outer cylinder, 4b is an inner cylinder, 5a is a filter paper, 5b and 5
1 is an outer porous metal plate, 5c and 5m are inner porous metal plates, 5d and 5e are end plates, 5i, 5
j, 5n and 5o are spacers (rings) made of plastic, etc., 5k is a lead wire, 5h is a glass seal, 5f and 5g are terminals, 21 and 22 are evaporators and condensers, 23 and 24 are blowers, 25 is a Expansion valve, 27 and 33 are electrical conversion circuits, 29 to 31
35 is an interface, 28 is a central controller, 32 is a temperature sensor, 34 is a temperature setting device, 26
is an accumulator. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. First and second cylinders made of a porous metal plate such as a wire mesh and arranged substantially concentrically with a certain gap in between in a refrigerant flow path in a suction strainer provided in a refrigerant cycle. A refrigerant state detector, characterized in that a refrigerant state detector is used as a counter electrode, and a refrigerant phase change in the refrigerant flow path is detected as a change in capacitance between the counter electrodes. 2. The refrigerant condition detector according to claim 1, wherein the first and second cylinders are arranged substantially concentrically via a cylindrical filter paper housed in a suction strainer. 3. Claim 1, characterized in that the first and second cylinders are arranged substantially concentrically with a certain gap in between on the inner peripheral surface side of a cylindrical filter paper housed in a suction strainer. Refrigerant condition detector as described. 4. Claim 1, characterized in that the first and second cylinders are arranged substantially concentrically on the outer peripheral surface side of the cylindrical filter paper housed in the suction strainer with a certain gap in between. refrigerant condition detector.