JP2001021437A - Gas leak sensor and absorption refrigerator mounted it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform speedy detection in the case oxygen of atmospheric component leaks into an absorption refrigerator. SOLUTION: This gas leak sensor is composed of two electrodes 102A and 102B separately supported by a mounting part 101 made of an insulating material (e.g. polyether ether ketone resin) and a thin wire 103 stretched between the electrodes 102A and 102B so that a tensile stress may act between them. The thin wire 103 is formed in a coil spring shape by cold-drawing metal containing Ni at 1.5% or more e.g. austenite stainless steel such as SUS-304 into, for example, 500 μm in diameter. In addition, the gas leak sensor 100 is mounted to a refrigerant pipe connecting a high-temperature regenerator to a low-temperature regenerator in an absorption refrigerator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an absorption refrigerator (including an absorption chiller / heater and an absorption heat pump).

[0002]

2. Description of the Related Art As is well known, an absorption refrigerator is constructed by sequentially connecting a regenerator, a condenser, an evaporator, an absorber and the like to a pipe, and using an aqueous solution of a halogen element salt (for example, lithium chloride or lithium bromide). When a refrigerant such as water is circulated while being absorbed or released by an absorbing liquid, it is a device that transfers heat to provide a cooling function such as cooling or a heating function such as heating.

In the absorption refrigerator having the above structure, a regenerator, a condenser, an evaporator, an absorber, and a pipe connecting them are formed of iron or stainless steel, and water is used as a refrigerant and lithium chloride is used as an absorption liquid. When an aqueous solution of lithium bromide or the like is used, the absorbing liquid reacts with the metal of the equipment material, and generates hydrogen gas when forming an anticorrosion film.

The absorption refrigerator has a high vacuum as a whole in order to quickly evaporate the refrigerant, but since it is a welded structure, intrusion of atmospheric components from pinholes and cracks is inevitable. Over time, atmospheric components such as nitrogen and oxygen increase.

[0005] Hydrogen gas generated by the above mechanism, and nitrogen gas and oxygen gas, which are air components that have entered the inside of the apparatus from the outside, do not condense in the degree of cooling in the refrigerator, and their solubility in the absorption liquid is extremely small. Stagnates in the non-solution part of the evaporator or absorber, and its concentration gradually increases.
When the concentration of the non-condensable gas such as hydrogen, nitrogen, and oxygen in the machine increases in this way, the evaporation of the refrigerant is suppressed, and the refrigeration capacity decreases.

[0006] For this reason, by a service person who has visited during the switching of air conditioning and heating, a. Detecting the amount of air bubbles discharged from a vacuum pump connected to the gas phase of the apparatus; b. Although pressure changes in the machine are checked using a pressure sensor, the increase in uncondensable gas cannot be reliably detected by these methods.

[0007] In addition, the non-condensable gas increasing in the machine,
Since it is not possible to determine whether the gas is hydrogen gas generated by the above mechanism or an atmospheric component leaked from the outside, the equipment components are exposed to oxygen of the atmospheric component leaked from the outside for a long time, and various corrosion forms There was an inconvenience that it could lead to a serious accident called corrosion penetration.

[0008]

Therefore, it is necessary to be able to detect even minute leaks of atmospheric components promptly and reliably, and this has been a problem to be solved.

[0009]

In order to solve the above-mentioned problems, the present invention comprises two electrodes supported separately from each other and a thin wire stretched between the two electrodes. A gas leak sensor having a first configuration,

In the gas leak sensor of the first configuration, the diameter of the thin wire is 500 μm or less.
A gas leak sensor having the configuration of

In the gas leak sensor according to the first aspect, the gas leak sensor according to the third aspect, wherein the thin line is a metal wire containing 1.5% or more of Ni;

An absorption refrigerator having a first configuration in which a thin wire of the gas leak sensor having any one of the first to third configurations is installed in a circuit in which the refrigerant vapor circulates;

[0013] In the absorption refrigerator of the first configuration, an on-off valve is installed in a refrigerant vapor circuit upstream of the gas leak sensor and in a refrigerant vapor circuit downstream of the gas leak sensor. A refrigerator,

[0014] In the absorption refrigerator of the second configuration, an absorption refrigerator of a third configuration, wherein an exhaust means is connected to a refrigerant vapor circuit provided with a gas leak sensor between the on-off valves,

In the absorption refrigerator of any one of the first to third configurations, the absorption refrigerator of the fourth configuration is such that the absorption liquid of the absorption refrigerator is an aqueous solution of a salt containing a halogen element. To provide.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. As shown in FIG. 1, a gas leak sensor 100 according to the present invention includes two electrodes 102A and 102B separated and supported by an attaching member 101 made of an insulating material, for example, a polyetheretherketone resin.
And a thin wire 103 stretched so that a tensile stress acts between the electrodes 102A and 102B.

The thin wire 103 is formed by cold-drawing a metal containing 1.5% or more of Ni, for example, austenitic stainless steel such as SUS-304 to a diameter of 500 μm, for example, to form a coil spring. is there.

Austenitic stainless steel,
In addition, the electrodes 102A, 10A,
When exposed to an atmosphere in which oxygen and chloride coexist, the fine wire 103 supported by 2B causes intragranular stress corrosion cracking.

That is, a metal containing Ni, for example, SUS
304 (18-8 austenitic stainless steel)
For example, as shown in FIG. 4, the higher the oxygen concentration, the higher the cracking susceptibility, and depending on the conditions (metal composition, chloride concentration in the atmosphere, and the magnitude of the acting tensile stress), the oxygen concentration becomes 1
Cracks occur even at ppm.

Moreover, the thin wire 103 having the stress corrosion cracking
Is easily broken because it is pulled by the electrodes 102A and 102B. Whether or not the thin wire 103 is broken can be easily determined by applying a voltage and checking the continuity between the electrodes 102A and 102B.

The gas leak sensor 100 having the above structure is attached to the refrigerant pipe 14 between the on-off valves 26 and 27 of the absorption refrigerator shown in FIG. 2, for example, in the manner shown in FIG. That is, a screw 101A for mounting is provided on the outer surface of the body of the attachment member 101, and the screw 101A is screwed into the screw 32A of the socket 32 attached to the refrigerant pipe 14, whereby the thin wire 103 of the gas leak sensor 100 is cooled. Tube 14
It is installed so as to be able to contact the refrigerant vapor flowing inside.

In the absorption refrigerator shown in FIG. 2, 1 is a high-temperature regenerator equipped with a gas burner 1B, 2 is a low-temperature regenerator, 3
Is a condenser, 4 is an evaporator, 5 is an absorber, 6 is a low-temperature heat exchanger, 7 is a high-temperature heat exchanger, 8 to 11 are absorption liquid tubes, 13 is an absorption liquid pump, 14 to 18 are refrigerant tubes, 19 Is a refrigerant pump,
21 is a cold / hot water pipe through which cold or hot water circulates to a cooling / heating load (not shown), 22 is a cold / hot water pump, 23 is a cooling water pipe, 24 and 25 are pressure equalizing pipes, and 26 to 31 are on-off valves. The machine uses an aqueous solution of water as the refrigerant and a halogen element salt such as lithium chloride as the absorbing liquid,
This is a double effect absorption refrigerator that circulates cold or hot water to the load. Note that the gas leak sensor 100, the on-off valve 2
Since the configuration that does not include the components 6 and 27 is conventionally known, the description of the operation of the absorption refrigerator itself is omitted.

By checking the presence or absence of conduction between the electrodes 102A and 102B constantly or periodically (for example, every hour), an increase in the outside air component in the machine is monitored with high accuracy.

That is, the vapor of lithium chloride, which is the absorbing liquid, is slightly (for example, 100 ppm) in the refrigerant vapor which is evaporated and separated from the absorbent in the high-temperature regenerator 1 and flows through the refrigerant pipe 14 toward the low-temperature regenerator 2. Degree) included.

When the concentration of lithium chloride is at this level and the oxygen concentration is less than 1 ppm, stress corrosion cracking does not occur in the thin wire 103, and when the oxygen concentration becomes 1 ppm or more, stress corrosion cracking occurs in the thin wire 103. The thin wire 10 is broken such that the thin wire 103 is broken starting from the crack.
In the gas leak sensor 100 formed by determining the metal composition of No. 3 and applying a required amount of tensile stress to the thin wire 103, the gas leak sensor 100 monitors the presence / absence of conduction between the electrodes 102A and 102B from the outside to the inside of the machine. If any air leaks, it can be detected.

On-off valves 26 and 27 are provided on both sides of the gas leak sensor 100 to prevent the degree of vacuum in the apparatus from being lowered when the gas leak sensor 100 is attached or detached, and that the thin wire 103 does not crack when the gas leak sensor 100 is attached. To do.

Further, a vacuum pipe 35 having a vacuum pump 33 and an on-off valve 34 shown by a broken line is connected to the refrigerant pipe 14 between the on-off valves 26 and 27, and the on-off valves 26 and 27 are closed.
The air present in the refrigerant pipe 14 is completely exhausted by the vacuum pump 33 and the gas leak sensor 100 is attached.
The air in the refrigerant pipe 14 between the vacuum pump 3 and
If the discharge is completed by 3 and the on-off valves 26 and 27 are opened thereafter, it is possible to further prevent cracking when the thin wire 103 is mounted and prevent the degree of vacuum in the machine from lowering.

Further, as shown in FIG. 5, the gas leak sensor 100 is provided in the middle of a bleed tube 38 extending from the absorber 5 to the ejector 37 of the bleed device 36 and a bleed tube 39 extending from the condenser 3. It may be provided. Also in this case, it is preferable that an on-off valve is provided on both sides of the gas leak sensor 100, and a vacuum pipe provided with a vacuum pump is connected between the on-off valves.

Further, the thin wire 103 may be supported by the electrodes 102A and 102B in a simply curved bar spring shape after cold drawing. When the thin wire 103 is curved, a compressive stress acts on a portion inside the center line, but a tensile stress acts on a portion outside the center line. Since stress corrosion cracking occurs on the part side, and the crack propagates from this part as a base point and the thin wire 103 breaks, it can be used in the same manner as when formed into a coil spring shape.

The tensile stress applied to the thin wire 103 is applied by an appropriate member other than the electrodes 102A and 102B, and the electrodes 102A and 102B are connected to both ends of the thin wire 103 to which the tensile stress is applied. The configuration described above is merely a configuration in which a tensile stress is applied to the fine wire 103 and a voltage is applied to the wires 102A and 102B, and the operation is simply performed by two members. It is included in.

The voltage applied to the electrodes 102A and 102B may be either an AC voltage or a DC voltage. In this case, a voltage is applied intermittently (for example, every hour) to check the continuity between the electrodes 102A and 102B.

On the other hand, when an AC voltage is applied to the electrodes 102A and 102B, there is no inconvenience that stress corrosion is unlikely to occur in the thin wire 103. In this case, a voltage is constantly applied and conduction between the electrodes 102A and 102B is performed. Can be checked.

Then, the electrode 1 is
When the electrical continuity between 02A and 102B is lost, a warning that air is leaking into the machine from the outside may be automatically output immediately.

The fine line 103 is only required to be cracked when exposed to an atmosphere in which the vapor of the absorbing solution and oxygen as the atmospheric component coexist. Is appropriately selected. And, in the austenitic stainless steel containing Ni, 0.4% or more of Cu and 1 to 1 in order to increase the susceptibility to stress corrosion cracking.
It may be configured to add about 3% of Mo.

The thin wire 103 is required to be easily broken by the acting tensile stress when stress corrosion cracking occurs. Therefore, its thickness is generally 500 μm or less, preferably 100 μm or less.

[0036]

According to the present invention, it is possible to immediately detect that even a small amount of oxygen in the atmosphere is present in the machine, so that the equipment components are exposed to the oxygen of the atmospheric component leaked into the machine from the outside for a long time. Disappears. For this reason, a serious accident such as corrosion penetration of the member does not occur.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a gas leak sensor according to the present invention.

FIG. 2 is an explanatory view of an absorption refrigerator according to the present invention.

FIG. 3 is an explanatory diagram showing an installation state of a gas leak sensor.

FIG. 4 is an explanatory diagram showing a state of occurrence of cracks.

FIG. 5 is an explanatory diagram of a modified embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High temperature regenerator 1B Gas burner 2 Low temperature regenerator 3 Condenser 4 Evaporator 5 Absorber 6 Low temperature heat exchanger 7 High temperature heat exchanger 8-11 Absorbing liquid pipe 13 Absorbing liquid pump 14-18 Refrigerant pipe 19 Refrigerant pump 21 Cold / hot water pipe DESCRIPTION OF SYMBOLS 22 Cold / hot water pump 23 Cooling water pipe 24/25 Equalizing pipe 26-31 On-off valve 32 Socket 32A screw 33 Vacuum pump 34 On-off valve 35 Vacuum pipe 36 Extraction device 37 Ejector 38/39 Extraction pipe 100 Gas leak sensor 101 Mounting member 101A screw 102A electrode 102B electrode 103 fine wire

Claims (7)

[Claims] 1. A gas leak sensor comprising two electrodes supported apart from each other and a thin wire stretched between the two electrodes. 2. The gas leak sensor according to claim 1, wherein the diameter of the thin wire is 500 μm or less. 3. The gas leak sensor according to claim 1, wherein the thin wire is a metal wire containing 1.5% or more of Ni. 4. A circuit in which refrigerant vapor circulates, wherein
3. An absorption refrigerator in which the thin wire of the gas leak sensor according to any one of 3) is installed. 5. The absorption refrigerator according to claim 4, wherein on-off valves are provided in the refrigerant vapor circuit upstream of the gas leak sensor and in the refrigerant vapor circuit downstream of the gas leak sensor. 6. The absorption refrigerator according to claim 5, wherein exhaust means is connected to a refrigerant vapor circuit in which a gas leak sensor is provided between the on-off valves. 7. The absorption liquid of the absorption refrigerator is an aqueous solution of a salt containing a halogen element.
6. The absorption refrigerator according to any one of 6.