JP4201467B2 - Absorption type vacuum breaker detector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vacuum break detection device for an absorption refrigerator.
[0002]
[Prior art]
In an absorption refrigerator, when vacuum breakage (ie, airtight breakage) occurs in an operating fluid system that circulates absorption liquid or refrigerant under a vacuumed low pressure condition, refrigerant evaporation is hindered by an increase in internal pressure, resulting in a large refrigerating capacity. In the worst case, the strong corrosiveness of the absorbing liquid is manifested due to the combination with the invading oxygen, leading to rapid internal corrosion. This was detected by monitoring the pressure of the working fluid system, such as detecting an increase in the internal pressure of the evaporator or the evaporator (see, for example, Japanese Patent Application Laid-Open No. 10-89796).
[0003]
[Problems to be solved by the invention]
However, in the conventional method of simply monitoring the pressure of the working fluid system, it is possible to determine whether the pressure change in the working fluid system is due to vacuum breakage or due to the internal generation of hydrogen gas seen in an absorption refrigerator. In this respect, there has been a problem that the vacuum breakage of the working fluid system (particularly, a slight vacuum breakage at the initial stage of occurrence, etc.) cannot be detected accurately and accurately.
[0004]
In view of this situation, the main object of the present invention is to enable accurate and accurate detection of the vacuum break of the absorption chiller with a rational detection configuration.
Another main problem of the present invention is to provide a vacuum break detection device having a high practical value that can also remove internally generated hydrogen which causes a reduction in the capacity of an absorption refrigerator.
[0005]
[Means for Solving the Problems]
  In the invention according to claim 1 or claim 2,
  A cell is formed by sandwiching an oxygen ion conductor between the porous inner electrode and the porous outer electrode,
  This cell is disposed in a state where the inner electrode faces the low-pressure airtight space on the working fluid system side in the absorption refrigerator and the outer electrode faces the atmospheric space,
  Detection means for detecting a potential difference between the two electrodes or a current in the conductive circuit by connecting the inner electrode and the outer electrode with a conductive circuit is provided.
[0006]
That is, in the above cell, in the state where both electrodes are connected by a conductive circuit, due to the oxygen partial pressure difference between the atmospheric space and the low pressure airtight space on the working fluid system side, While accompanying the reaction, the oxygen ion conductor in the cell is moved from the outside electrode toward the inside electrode.^2-As a result, a potential difference corresponding to the oxygen partial pressure difference between the two spaces is generated between the in-machine electrode and the out-of-machine electrode.
2O^2-→ O₂+ 4e^-  ……(I)
[0007]
Therefore, if the potential difference or the current of the conductive circuit is detected by the detection means, the oxygen partial pressure difference between the atmospheric space and the low-pressure airtight space can be grasped based on the detected potential difference or the detected current. In addition, a vacuum break that has occurred in the low-pressure gas-tight space on the working fluid system side can be detected by reducing the detection current (that is, reducing the difference in oxygen partial pressure between the two spaces due to an increase in the oxygen partial pressure in the low-pressure gas-tight space).
[0008]
And if this vacuum break detection, it is possible to detect the vacuum break distinctly from the pressure change of the working fluid system caused by the internal generation of hydrogen gas seen in the absorption refrigerator, Compared to the previous method that simply monitors the pressure of the working fluid system, it can detect the vacuum break more accurately and accurately, and accurately grasp the degree of oxygen penetration that causes the worst internal corrosion trouble. These allow for a more appropriate response to vacuum breaks.
[0009]
Moreover, the hydrogen gas H present in the low-pressure gas-tight space on the working fluid system side is obtained by the reaction of the following equation (b) at the in-machine electrode accompanying the ion movement.₂(Ie, hydrogen gas generated internally in the working fluid system)₂It can also be removed in the form of O,
H₂+ O^2-→ H₂O + 2e^-  (B)
In this regard, as a device that has both a vacuum break detection function and a hydrogen gas removal function, it absorbs the oxygen concentration (partial pressure) in the low-pressure gas-tight space on the working fluid system side using another oxygen sensor. There is an advantage that it can be used to prevent a decrease in capacity caused by the internal generation of hydrogen gas in a refrigerator.
[0010]
Note that the potential difference Ea generated between the in-machine electrode and the out-of-machine electrode is a value represented by the following Nernst equation (C).
Ea = RT / 4F · ln (Poo / Poi) (C)
Where R: gas constant
T: Absolute temperature
F: Faraday constant
Poo: Oxygen partial pressure in the atmospheric space facing the outboard electrode
Poi: Partial pressure of oxygen in the low-pressure airtight space facing the in-machine electrode
[0011]
Further, in this vacuum break detection using oxygen ion conduction, oxygen gas O in the low-pressure airtight space is obtained by the reaction of the above equation (a).₂Oxygen gas enters the low-pressure airtight space from the atmospheric space, but it is suitable for oxygen ion movement due to the partial pressure difference of oxygen by selecting the cell size or selecting the oxygen ion passage resistance of the cell. If restrictions are added, the generation of oxygen gas in the low-pressure airtight space associated with this vacuum break detection should be of a level that does not cause any particular problems in maintaining the refrigeration capacity of the absorption chiller properly. it can.
[0012]
  Invention according to claim 1 or claim 2In the implementation of the present invention, as the oxygen ion conductor, various electrolytes such as zirconia, cerium oxide, and hafnium oxide can be adopted as long as the electrolyte has oxygen ion conductivity, and yttrium and calcium are also used as stabilizers. Various materials such as scandium, ytterbium, and magnesium can be used. However, if stabilized zirconia is used for the oxygen ion conductor, it is advantageous in terms of chemical stability, and if partially stabilized zirconia is used, strength ( It is also advantageous in terms of toughness and cost.
[0013]
  In the invention according to claim 1 or 2, in addition to the above-described configuration,
  There is provided gate means capable of switching between a closed state for restricting or blocking oxygen ion movement in the oxygen ion conductor and an open state for releasing the restriction or blocking.
[0014]
In other words, in this configuration, the vacuum break detection based on the detection potential difference or detection current of the detection means is performed in a timely manner at an appropriate time, and the gate means is opened at the time of each detection. During the detection pause period, a detection mode is adopted in which the gate means is closed.
[0015]
In other words, when the vacuum break detection is performed at appropriate time intervals as described above, the gate means is closed during the detection pause period, so that the reaction in the low-pressure airtight space due to the reaction of the formula (A) is performed. Oxygen gas generation during the detection pause period can be suppressed, thereby effectively reducing the amount of oxygen gas generation as a whole throughout the detection pause period and the detection execution time in the low-pressure airtight space, It becomes more excellent in maintaining the refrigeration capacity of the absorption refrigerator.
[0016]
And while suppressing the generation of oxygen gas in the low-pressure airtight space more effectively in this way, when the detection is performed each time, by opening the gate means, the vacuum is maintained properly and the vacuum is maintained. Changes in the amount of oxygen ion transfer due to changes in the partial pressure of oxygen in the low-pressure gas-tight space when destruction occurs (in other words, changes in the detection potential difference and detection current by the detection means) can be made to appear significantly. Thereby, the vacuum break can be accurately and accurately detected based on the detection potential difference or the detection current by the detection means in the open state.
[0017]
It should be noted that either a form for restricting or blocking oxygen ion movement in the oxygen ion conductor in the closed state may be adopted, but if a form for restricting oxygen ion movement to an appropriate amount in the closed state is adopted, low-pressure airtightness is adopted. In addition to the function of suppressing the generation of oxygen gas in the space, the hydrogen gas removal function by the reaction (b) can be expressed in a closed state, and thus a high hydrogen gas removal function can be obtained together.
[0018]
  In carrying out the invention according to claim 1 or claim 2, the following configuration may be implemented as the invention according to claim 3. That is,In the invention according to claim 3,
  As the gate means, the closed state is revealed by applying a predetermined DC voltage to both electrodes in a state where the in-machine electrode is set to a negative electrode, and the open state is stopped by stopping the voltage application. Is provided.
[0019]
In other words, if a DC voltage is applied to the outboard electrode and the inboard electrode with the inboard electrode being the negative electrode, oxygen ion movement due to the oxygen partial pressure difference toward the inboard electrode side of the oxygen ion conductor is electrically Deterred by natural repulsion. Therefore, if a power supply device that can be switched between a state in which a DC voltage is applied to both electrodes in a state in which the inner electrode is made negative and a state in which the voltage application is stopped, is provided as a gate means, The closed state can be revealed by applying a voltage, and the open state can be revealed by stopping the voltage application.
[0020]
That is, in the above-described configuration in which switching between the closed state and the open state is performed by applying the DC voltage and stopping the voltage application, for example, the state in which the outside electrode is exposed to the atmospheric space and the outside electrode Compared with the case where the gate means is configured with a mechanical means for switching to a state of shielding against the atmospheric space, the switching operation between the closed state and the open state and the switching operation structure can be simplified.
[0021]
Further, the applied voltage Eb by the power supply device is set to an appropriate value according to the adjustment target upper limit value Px of the oxygen partial pressure Poi and the adjustment target upper limit value Py of the hydrogen partial pressure Ph in the low-pressure airtight space on the working fluid system side. The closed state (that is, oxygen ions) in which the function of suppressing the generation of oxygen gas due to the reaction of formula (a) in the low-pressure airtight space and the function of removing hydrogen gas by the reaction of formula (b) coexist. (Closed state in which the movement is limited to an appropriate amount), and the function of maintaining the oxygen partial pressure Poi and the hydrogen partial pressure Ph in the low-pressure hermetic space within appropriate ranges below the respective adjustment target upper limit values Px and Py. Can do.
[0022]
That is, the applied voltage Ebx for maintaining the oxygen partial pressure Poi in the low pressure hermetic space at the adjustment target upper limit value Px is given by the following equation (c), and the hydrogen partial pressure Ph in the low pressure hermetic space is set as the adjustment target upper limit value. Since the applied voltage Eby maintained at Py is given by the following equation (d),
Ebx = RT / 4F · ln (Poo / Px) (Cha ')
Eby = Eo + RT / 2F · ln [Ps / (Poo^1/2・ Py)] …… (D)
Where Eo: standard potential of the reaction in which water is produced from oxygen and hydrogen
R: Gas constant
T: Absolute temperature
F: Faraday constant
Ps: Water vapor partial pressure in the low-pressure secret space facing the inner electrode
Poo: Oxygen partial pressure in the atmospheric space facing the outboard electrode
The above-described detection mode in which the vacuum break detection based on the detection potential difference or detection current by the detection means is carried out in a timely manner (ideally, the detection execution time in the open state is ignored compared to the detection pause period in the closed state) In the repetitive detection mode limited to the shortest possible time), if the voltage Eb applied by the power supply device is set to a value satisfying the following equation (e), the oxygen partial pressure Poi and the hydrogen content in the low pressure hermetic space A function for keeping the pressure Ph in an appropriate range below the respective adjustment target upper limit values Px and Py is generated.
Ebx ≦ Eb ≦ Eby (e)
[0023]
  In the invention according to claim 1, in addition to the common configuration of the invention according to claim 1 and claim 2,
  Performing periodic control to periodically and timely switch the gate means to an open state;
  Under the execution of this periodic control, there is provided control means for executing predetermined abnormality response control when the detection potential difference or detection current by the detection means when the gate means is in an open state becomes smaller than a set threshold value.
[0024]
In other words, in this configuration, the above-mentioned timed vacuum break detection periodical period in which the gate means is opened for a time period, and the vacuum break is detected based on the detection potential difference or the detection current by the detection means when in the open state. The control means is automatically made to perform the target implementation.
[0025]
And when the detection potential difference or the detection current becomes smaller than the set threshold in each timed vacuum break detection, that is, when the oxygen partial pressure difference between the atmospheric space and the low-pressure airtight space becomes smaller than a predetermined threshold, Assuming that a vacuum break has occurred, the control means is caused to execute a predetermined abnormality response control for the vacuum break.
[0026]
That is, the vacuum break detection accompanying the switching of the gate means as described above and the control means automatically perform the control for the abnormality when the vacuum break occurs, so that the vacuum break detection is managed by the absorption refrigerator. Compared to letting a person perform it artificially, the burden on the administrator can be reduced and the response to the vacuum break can be made more accurate.
[0027]
  Invention according to claim 1In the implementation of the above, the abnormality response control to be executed by the control means includes, for example, an emergency stop of the absorption refrigeration machine, an alarm, an injection of a corrosion inhibitor, or an abnormal communication to the management center using a communication line. In addition, the set threshold value may be provided in a plurality of stages, and different abnormality response control may be executed for each threshold value (that is, different abnormality response control depending on the degree of vacuum break). .
[0028]
The above-described power supply device is adopted as the gate means, and the applied voltage Eb of the power supply device is set within an appropriate range in which the oxygen partial pressure Poi and the hydrogen partial pressure Ph in the low-pressure airtight space are below the respective adjustment target upper limit values Px and Py. In the case of adopting an embodiment in which the value is set to a value that is maintained (a value that satisfies the expression (e)), it goes without saying that the set threshold value is based on the adjustment target upper limit value Px of the oxygen partial pressure Poi in the low-pressure airtight space. Is set to a value corresponding to a large oxygen partial pressure Poi.
[0029]
  In the invention according to claim 2, in addition to the common configuration of the invention according to claim 1 and claim 2,
  As the low-pressure airtight space facing the in-machine electrode, a detection chamber connected to the working fluid system of the absorption chiller through an on-off valve is provided,
  The gate means is opened in a timely manner when the on-off valve is opened regularly and in a timely manner, and the on-off valve is in a closed state at a timing close to each opening operation of the on-off valve. In addition to executing periodic control to switch to
  Under the execution of this periodic control, when the detection potential difference or the detection current by the detection means when the gate means is in the open state becomes smaller than a set threshold value, the subsequent opening / closing of the on-off valve is performed as predetermined abnormality response control. Control means for disabling valve operation is provided.
[0030]
That is, in this configuration, in the configuration in which the in-machine electrode of the cell is exposed to the detection chamber connected to the working fluid system of the absorption refrigeration machine via the on-off valve, the on-off valve is opened regularly and timely. By maintaining the state, the oxygen partial pressure in the detection chamber (the oxygen partial pressure Poi in the low-pressure airtight space) is normally kept equal to the oxygen partial pressure in the working fluid system, and is removed by the reaction of the above (b) equation. Hydrogen gas (hydrogen gas generated in the working fluid system) is introduced into the detection chamber.
[0031]
In addition, when a vacuum break occurs in the detection chamber itself due to, for example, a cell breakage or a seal breakage in the cell attachment portion, the open / close valve in a closed state that the vacuum break immediately reaches the working fluid system (That is, an on-off valve that is in a valve closing period in periodic and timed valve opening control).
[0032]
And the periodic implementation of the above-mentioned timed vacuum break detection that detects the vacuum break based on the detection potential difference or the detection current by the detection means when the gate means is opened in a timely manner, When the on-off valve is in the closed state at each time of the opening / closing operation of the on-off valve, the control means is automatically executed in such a manner that the gate means is opened, and this time-limited vacuum break detection is performed. When the detected potential difference or detected current becomes smaller than the set threshold value, a vacuum break occurred (that is, the vacuum break that occurred in the working fluid system reached the detection chamber when the on-off valve was opened last time or was detected. Assuming that a vacuum break has occurred in the chamber itself), the control means is caused to execute an abnormality handling control that makes the subsequent opening operation of the on-off valve non-executable.
[0033]
That is, according to this configuration, a vacuum break that occurs in the working fluid system is detected in a detection chamber that normally maintains an oxygen partial pressure equivalent to that of the working fluid system, while providing a vacuum break detection function for the working fluid system. However, when a vacuum break occurs in the detection chamber itself due to a cell breakage or a seal breakage of the cell mounting portion, the above-described abnormality response control (that is, closing the on-off valve) means that the vacuum break affects the working fluid system. The control of the valve state) prevents the working fluid system.
[0034]
In addition, by detecting the vacuum break with the switching of the gate means and the opening / closing valve as described above and controlling the abnormality when the vacuum break occurs, the control means automatically performs such a vacuum break detection. Compared to making the machine administrator perform it manually, the burden on the administrator can be reduced, and the response to the vacuum break can be made more accurate.
[0035]
  Invention according to claim 2In the implementation of the above, the control means includes, for example, a stop operation of the absorption refrigeration machine, an alarm issuance, or a management center using a communication line as an abnormality response control, with subsequent non-execution of the valve opening operation. It is desirable to execute other abnormality response control such as abnormal communication, etc. Also, the above set thresholds are provided in multiple stages, and different abnormality response control (abnormality control depending on the degree of vacuum breakage) for each threshold is provided. Even if you let it runGood.
[0036]
  In addition,Invention according to claim 1Similarly to the above, the above-described power supply device is adopted as the gate means, and the applied voltage Eb of the power supply device is set to the adjustment target upper limit values Px, Py for the oxygen partial pressure Poi and the hydrogen partial pressure Ph in the low-pressure hermetic space (detection chamber). In the case of adopting an embodiment in which the following value is set to a value (a value satisfying the expression (e)), it is a matter of course that the set threshold value is the oxygen content in the low-pressure airtight space (detection chamber). The pressure Poi is set to a value corresponding to an oxygen partial pressure Poi that is larger than the adjustment target upper limit value Px.
[0037]
  In carrying out the invention according to claim 2, in the invention according to claim 4,
  Gas extraction means is provided for sending hydrogen gas generated in the working fluid system into the detection chamber when the on-off valve is open.
[0038]
That is, according to this configuration, the hydrogen gas generated in the working fluid system is introduced into the detection chamber by opening the on-off valve and removed by the reaction (b). In comparison with introducing hydrogen gas into the detection chamber, the hydrogen gas generated in the working fluid system can be more efficiently removed by forcibly feeding the hydrogen gas into the detection chamber by the gas extraction means.
[0039]
Further, not only hydrogen gas but also non-condensable gas other than hydrogen gas such as oxygen gas can be eliminated from the working fluid system by the feeding function of the gas extraction means, and from these, the vacuum state of the working fluid system can be reduced. It is possible to further enhance the function of maintaining the refrigerating capacity at a high level by maintaining it appropriately.
[0040]
Various types of gas extraction means may be employed as long as they have a pump function for gas, including an ejector.
[0041]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a double-effect absorption refrigerator using water as a refrigerant and a lithium bromide solution as an absorption liquid, and a solution pump from the bottom of the absorber 1 (common bottom with an evaporator 10 described later). 2 and the low-temperature absorbent La (diluted absorbent) returned to the high-temperature regenerator 4 through the solution heat exchanger 3 is heated by the burner 5 to generate refrigerant vapor Rs from the diluted absorbent La, The absorption liquid Lb having a medium concentration due to the generation of the refrigerant vapor Rs is introduced into the low temperature regenerator 6 after heat exchange with the diluted absorption liquid La in the high temperature side heat exchange section 3a of the solution heat exchanger 3. The refrigerant vapor Rs generated in the high-temperature regenerator 4 is exchanged with the heat transfer cylinder 7 to generate further refrigerant vapor Rs ′ from the medium concentration absorbent Lb.
[0042]
Then, the refrigerant R partially or wholly condensed by heat exchange with the medium concentration absorbent Lb through the heat transfer cylinder 7 and the refrigerant vapor Rs ′ generated in the low temperature regenerator 6 are introduced into the condenser 8. The refrigerant R is cooled by the passing cooling water W in the condenser coil 9, and the refrigerant R completely condensed by this cooling is dispersed inside the evaporator 10, and is evaporated by taking the heat of vaporization from the passing cold water C in the evaporator coil 11. By doing so, the passing cold water C of the evaporator coil 11 to be cooled is cooled.
[0043]
On the other hand, the absorption liquid Lc (concentrated absorption liquid) having a high concentration due to generation of the refrigerant vapor Rs ′ in the low-temperature regenerator 6 exchanges heat with the dilute absorption liquid La in the low-temperature side heat exchange section 3b of the solution heat exchanger 3. After being dispersed inside the absorber 1, in this absorber 1, the evaporated refrigerant in the evaporator 10 is absorbed by the sprayed concentrated absorbent Lc under cooling by the passing cooling water W of the absorber coil 12. The inside of the evaporator 10 is maintained at a low pressure state suitable for refrigerant evaporation. Then, the absorption liquid La (diluted absorption liquid) having a low concentration again due to the absorption of the refrigerant is sent to the high-temperature regenerator 4 by the solution pump 2 so that the refrigerant R and the absorption liquid L, which are working fluids, are repeatedly circulated in the apparatus. Continue the operation of the absorption refrigerator (cold water generation operation).
[0044]
Reference numeral 13 denotes a switching valve for hot water generation operation. In the hot water generation operation, the switching valve 13 is opened and the refrigerant vapor Rs generated in the high-temperature regenerator 4 is short-circuited to the evaporator 10 to increase the temperature. The passing hot water H of the evaporator coil 11 to be heated is heated by the refrigerant vapor Rs.
[0045]
X is an additional device that doubles as a hydrogen gas removal device and a vacuum breakage detection device. The device configuration is appropriate for the operating fluid system that circulates the absorbing liquid and refrigerant under a vacuumed state (for example, an evaporator). 10 and an absorber 1) are connected to an airtight container-like detection chamber 16 which also serves as a gas removal chamber via a gas extraction means 14 and an on-off valve 15, and, as shown in FIG. 2, 2 made of platinum (Pt) Partially stabilized zirconia (for example, 6% yttria stabilized zirconia (Zr_0.94Y_0.06O_2-A bottomed cylindrical cell 19 having a structure sandwiching α)) faces the inside of the detection chamber 16 with one electrode 17a as an in-machine electrode and the outside atmospheric space with the other electrode 17b as an out-board electrode. It is attached to the chamber wall 16w of the detection chamber 16 in the state of facing A.
[0046]
Further, as shown in FIG. 2, a detection circuit 21 is provided for detecting a potential difference Ea between the electrodes 17a and 17b by connecting the inner electrode 17a and the outer electrode 17b with a conductive circuit 20, and further, an atmospheric space A and Gate means capable of switching between a closed state for restricting oxygen ion movement in the oxygen ion conductor 18 and an open state for releasing the restriction due to a difference in oxygen partial pressure with respect to the detection chamber 16 which is a low pressure airtight space on the working fluid system side. The switch element 22a opens the conductive circuit 20 on the detection circuit 21 side, and a DC power source 22b is connected to both electrodes 17a and 17b, and the DC power source 22b uses a predetermined DC voltage with the inner electrode 17a as a negative electrode. By applying Eb to both the electrodes 17a and 17b, the above closed state appears, and the switch element 22a conducts the conduction on the detection circuit 21 side. The electrodes 17a closes the road 20, turned down a connection of the DC power supply 22b for 17b, the electrodes 17a, is provided with power supply 22 for revealing the open state by stopping voltage application to 17b.
[0047]
As a control means, as shown in FIG. 3, the open / close valve 15 is limited for each set interval time Ta (for example, several hours) for a set valve opening time Tb (for example, several tens of seconds) that is extremely shorter than the interval time Ta. When the on-off valve 15 is in a closed state at a time close to each opening operation of the on-off valve 15 (that is, at the end of each interval time Ta), the set detection time Tc (for example, tens of seconds) ) Only when the periodic control for switching the power supply device 22 as the gate means to the open state (that is, the state where the voltage application is stopped) is performed for a limited time, and by the detection circuit 21 in the open state under the execution of the regular control. When the detected potential difference Ea becomes smaller than the set threshold value Ez, the subsequent valve opening operation of the on-off valve 15 is unsuccessful as an abnormality response control against vacuum break As well as to, it is provided with a controller 23 which performs issuance of shutdown and alarm absorption refrigerating machine.
[0048]
That is, in the cell 19, the main electrode at the inner electrode 17 a is caused by the oxygen partial pressure difference between the atmospheric space A and the detection chamber 16 in the open state where both electrodes 17 a and 17 b are connected by the conductive circuit 20 on the detection circuit 21 side. The oxygen ion conductor 18 is moved from the outside electrode 17b toward the inside electrode 17b through the reaction of the following formula (a).^2-As a result, a potential difference Ea (a potential difference represented by the following Nernst equation (C)) between the inner electrode 17a and the outer electrode 17b corresponds to the oxygen partial pressure difference between the spaces A and 16. Arise.
2O^2-→ O₂+ 4e^-  ……(I)
Ea = RT / 4F · ln (Poo / Poi) (C)
Where R: gas constant
T: Absolute temperature
F: Faraday constant
Poo: oxygen partial pressure in atmospheric space A
Poi: oxygen partial pressure in the detection chamber 16
[0049]
By using this, in the additional device X, the oxygen partial pressure in the detection chamber 16 is normally kept equal to the oxygen partial pressure of the working fluid system by periodically opening the on-off valve 15. When the potential difference Ea between the electrodes 17a and 17b in the open state detected by the detection circuit 21 at the end of the interval time Ta becomes smaller than the set threshold value Ez (that is, the oxygen content in the atmospheric space A and the detection chamber 16). When the pressure difference becomes smaller than a predetermined threshold value), a vacuum break occurs in the working fluid system, and the vacuum break reaches the detection chamber 16 by the previous opening of the on-off valve 15 or the on-off valve 15 is closed. When the vacuum break occurs in the detection chamber 16 itself during the valve period, the above-described abnormality response control is executed.
[0050]
Further, in this vacuum break detection, the on-off valve 15 is opened for each time in a timely manner, and the subsequent opening operation of the on-off valve 15 is performed as one of the abnormality control when it is recognized that the vacuum break has occurred. By not performing the operation, when the vacuum break is caused in the detection chamber 16 itself due to the breakage of the cell or the seal of the cell attachment portion, the vacuum break is prevented from reaching the working fluid system and operates. The fluid system is protected.
[0051]
In addition, in this additional device X, a voltage value satisfying the following equations (c), (d), and (e) is adopted as the DC voltage Eb applied to both electrodes 17a and 17b by the power supply device 22. Thus, the hydrogen gas H introduced into the detection chamber 16 when the on-off valve 15 is opened, together with the function of suppressing the generation of oxygen gas in the detection chamber 16 due to the reaction of the formula (A).₂(That is, hydrogen gas generated in the working fluid system) is converted into water molecules H by reaction of the following equation (b) at the in-machine electrode 17a.₂By coexisting in the closed state the function of removing in the form of O,
Ebx = RT / 4F · ln (Poo / Px) (Cha ')
Eby = Eo + RT / 2F · ln [Ps / (Poo^1/2・ Py)] …… (D)
Ebx ≦ Eb ≦ Eby (e)
Where Eo: standard potential of the reaction in which water is produced from oxygen and hydrogen
R: Gas constant
T: Absolute temperature
F: Faraday constant
Ps: Water vapor partial pressure in the gas removal chamber 16
Poo: oxygen partial pressure in atmospheric space A
Px: Adjustment target upper limit value of oxygen partial pressure in the detection chamber 16
Py: Adjustment target upper limit value of hydrogen partial pressure in the detection chamber 16
H₂+ O^2-→ H₂O + 2e^-  (B)
As described above, in the detection mode in which the detection execution time Tc in the open state is limited to a time shorter than the detection pause period in the closed state, the oxygen partial pressure Poi in the detection chamber 16 is less than or equal to the adjustment target upper limit value Px. In addition to the function of maintaining the proper range, the hydrogen partial pressure Ph of the detection chamber 16 also has a function of maintaining the proper range of the adjustment target upper limit value Py or less, thereby generating the generated hydrogen gas H in the working fluid system.₂It is made to function together as a device which removes.
[0052]
On the other hand, the gas extraction means 14 generates hydrogen gas H in the working fluid system.₂And inhaled hydrogen gas H₂Is supplied to the detection chamber 16 when the on-off valve 15 is opened, so that the hydrogen gas can be removed more efficiently. In the present embodiment, as shown in FIG. A part La ′ of the rare absorbing liquid La to be sent out is guided to the ejector 25 as a reference fluid through the branch path 24, and an appropriate portion of the working fluid system is obtained by the attraction action caused by the high-speed flow of the rare absorbing liquid La ′ in the ejector 25. Gas suction is performed from the suction path 26 (for example, the evaporator 10 or the absorber 1).
[0053]
Then, the diluted absorbing liquid La ′ and the sucked hydrogen gas H functioned as the reference fluid₂Is ejected from the tip of the internal ejection pipe 27 connected to the downstream side of the ejector 25, so that the rare absorbing liquid La ′ and the suctioned hydrogen gas H are ejected at the ejection part.₂And gas-liquid separation, and this separated hydrogen gas H₂Is sent to the detection chamber 16 when the on-off valve 15 is opened. 28 is an ejection from the internal ejection pipe 27, and hydrogen gas H₂And a dilute absorption liquid La ′ separated and returned to the common bottom of the absorber 1 and the evaporator 10 by a pressure difference.
[0054]
In FIG. 2, 29 is a screw fixture for fixing the cell 19, 30 is a seal member made of gold (Au) or copper (Cu), 31 is a heater for heating the cell 19 to a predetermined temperature, and the cell 19 is necessary. One or a plurality of cells are installed in the detection chamber 16 according to the amount of hydrogen gas removed. However, when a plurality of cells 19 are installed, it is not necessary to use all of the plurality of cells 19 for vacuum break detection. Only the cell 19 of the part is used for the detection of the vacuum break accompanied by the switching between the open state and the closed state, and the other cells 19 are used only for removing hydrogen gas while maintaining the application state of the DC voltage Eb. You may do it.
[0055]
In addition, about the absorption refrigerator of this embodiment, the following value can be mentioned as an example of the operation specification.
Ps = 0.04 × 101.325 (kPa)
Poo = 0.21 × 101.325 (kPa)
Eo = 1.11 (V)
T = 600 (K)
Px = 0.001 (kPa)
Py = 0.001 × 101.325 (kPa)
Eb = 0.955 (V)
Ez = 0.069 (V) (potential difference corresponding to Poi = 0.1 kPa)
[0056]
[Another embodiment]
Next, other embodiments of the present invention will be listed.
[0057]
In the above-described embodiment, a configuration is adopted in which the in-machine electrode 17a is exposed to the detection chamber 16 (gas removal chamber) connected to the working fluid system via the on-off valve 15, but instead, as shown in FIG. The cell 19 may be equipped in such a manner that the inner electrode 17a faces the detection chamber 16 ′ that is always in communication with an appropriate portion such as the absorber 1 and the evaporator 10 in the working fluid system through the communication passage 26 ′. Further, the cell 19 may be provided in such a state that the inner electrode 17a directly faces an appropriate portion such as the absorber 1 or the evaporator 10 in the working fluid system, and the operating flow that faces the inner electrode 17a. The low-pressure airtight space on the system side may be any suitable space of the working fluid system in the absorption refrigerator or a space additionally connected to the working fluid system.
[0058]
Further, in the case of adopting the above-described cell equipment configuration in which the on-off valve 15 is not provided, the gate means 22 (power supply device) is periodically and timed instead of the automatic detection with the on-off valve control shown in the above embodiment. The control means 23 executes periodic control for switching to the open state at the same time, and under the execution of this periodic control, the detection potential difference Ea by the detection circuit 21 when the gate means 22 is in the open state becomes smaller than the set threshold value Ez. Sometimes, the control means 23 may execute a predetermined abnormality response control.
[0059]
In the above-described embodiment, the potential difference Ea between the electrodes 17a and 17b in the state where the in-machine electrode 17a and the out-of-machine electrode 17b of the cell 19 are connected by the conductive circuit 20 (potential difference caused by oxygen ion conduction due to oxygen partial pressure difference). Is detected by the detecting means 21, and the vacuum break is detected based on the detected potential difference Ea. Instead of this, the current Ia in the conductive circuit 20 in a state where both electrodes 17a and 17b are connected by the conductive circuit 20 is detected. (A current generated by oxygen ion conduction due to an oxygen partial pressure difference) may be detected, and a vacuum break may be detected based on the detected current Ia.
[0060]
The gate means is not limited to the above-described power supply device 22 that brings out the closed state by applying the DC voltage Eb to both the electrodes 17a and 17b of the cell 19. In some cases, the both electrodes 17a and 17b are used. The closed state can be obtained by simply shutting off the conductive circuit 20 connecting the two, and the closed state can be obtained by switching between a state in which the outside electrode 17b is exposed to the atmospheric space A and a state in which it is shielded from the atmospheric space A. Various switching methods such as a method of switching and displaying the state and the open state can be adopted.
[0061]
In the above-described embodiment, the oxygen ion movement in the oxygen ion conductor 18 is limited to an appropriate amount in the closed state. However, in some cases, the oxygen ion movement in the oxygen ion conductor 18 in the closed state is limited. You may make it interrupt.
[0062]
In the apparatus configuration shown in the above-described embodiment, the gas extraction means 14 may be omitted. In addition, in the apparatus configuration shown in FIG. 4, the gas extraction means may be additionally provided. What kind of bleed-out type should be adopted may be appropriately determined according to conditions and the like.
[0063]
The porous inner electrode 17a and the porous outer electrode 17b in the cell 19 are not limited to platinum, and various electrode materials can be used as long as they have sufficient strength and corrosion resistance. The shape of 19 is not limited to the bottomed cylindrical shape as shown in the above-described embodiment, and may be a flat or corrugated cell shape, for example.
[0064]
The vacuum break detection device according to the present invention is not necessarily limited to use as a hydrogen gas removal device, and may be used only for vacuum break detection of an absorption refrigerator.
[0065]
The vacuum break detection device according to the present invention is not limited to a double-effect absorption refrigerator, but can be applied to various types of absorption refrigerators including a single-effect type and a triple-effect type, and a refrigerant other than water. It can also be applied to absorption refrigerators that use absorption liquids other than lithium bromide solutions.
[Brief description of the drawings]
1 is a block diagram of an absorption refrigerator
FIG. 2 is an enlarged view showing a cell structure and a structure around the cell.
FIG. 3 is a graph showing the detection operation of the control means.
FIG. 4 is a configuration diagram of an absorption refrigerator showing another embodiment.
[Explanation of symbols]
14 Gas extraction means
15 On-off valve
16 Low pressure airtight space, detection room
17a Inside electrode
17b Outer electrode
18 Oxygen ion conductor
19 cells
20 Conductive circuit
21 Detection means
22 Gate means, power supply
23 Control means
A Atmospheric space
Ea Potential difference
Eb Applied DC voltage

Claims (4)

A cell is formed by sandwiching an oxygen ion conductor between the porous inner electrode and the porous outer electrode,
This cell is disposed in a state where the inner electrode faces the low-pressure airtight space on the working fluid system side in the absorption refrigerator and the outer electrode faces the atmospheric space,
A detecting means for detecting a potential difference between the electrodes or a current of the conductive circuit by connecting the inner electrode and the outer electrode with a conductive circuit ;
Providing a gate means capable of switching between a closed state for limiting or blocking oxygen ion movement in the oxygen ion conductor and an open state for releasing the limitation or blocking;
The periodic control for switching the gate means to the open state periodically and timely is executed, and the detection potential difference or the detection current by the detection means when the gate means is in the open state is set under the execution of the periodic control. A vacuum breakage detection device for an absorption refrigeration machine provided with a control means for executing predetermined abnormality response control when it becomes smaller than a threshold value . A cell is formed by sandwiching an oxygen ion conductor between the porous inner electrode and the porous outer electrode,
This cell is disposed in a state where the inner electrode faces the low-pressure airtight space on the working fluid system side in the absorption refrigerator and the outer electrode faces the atmospheric space,
A detecting means for detecting a potential difference between the electrodes or a current of the conductive circuit by connecting the inner electrode and the outer electrode with a conductive circuit;
And closed state to limit or block the oxygen ion migration in the oxygen ion conductor, a gate means capable of switching to an open state for releasing the restriction or blockage is provided,
As the low-pressure airtight space facing the in-machine electrode, a detection chamber connected to the working fluid system of the absorption chiller through an on-off valve is provided,
The gate means is opened in a timely manner when the on-off valve is opened regularly and in a timely manner, and the on-off valve is in a closed state at a timing close to each opening operation of the on-off valve. When the periodic potential control or the detected current by the detecting means when the gate means is in an open state becomes smaller than a set threshold value under the execution of the periodic control, a predetermined abnormality handling is performed. A vacuum breakage detection apparatus for an absorption refrigeration machine provided with control means for making the subsequent opening operation of the on-off valve non-executable as control . As the gate means, the closed state is revealed by applying a predetermined DC voltage to both electrodes in a state where the in-machine electrode is set to a negative electrode, and the open state is stopped by stopping the voltage application. The vacuum break detection device for an absorption refrigerator according to claim 1 or 2, further comprising a power supply device for displaying The vacuum breakage detection device for an absorption refrigerating machine according to claim 2, further comprising gas extraction means for sending hydrogen gas generated in the working fluid system into the detection chamber when the on-off valve is open .

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