JP4007777B2 - Diaphragm pump, diaphragm damage detection method for diaphragm pump, and ammonia absorption refrigerator equipped with the diaphragm pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a diaphragm pump, a diaphragm damage detection method for a diaphragm pump, and an ammonia absorption refrigerator equipped with the diaphragm pump.
[0002]
[Prior art]
Ammonia absorption chillers use water as an absorbent and use ammonia, which is a non-fluorocarbon natural refrigerant instead of a general chlorofluorocarbon as a refrigerant. Conventionally, ammonia is a toxic substance. For this reason, it has not become so popular because of the risk of leakage and the fact that the device itself has a large and complicated structure and the equipment cost is high.
However, in recent years, destruction of the ozone layer by CFCs has become a problem, and ammonia absorption refrigerators that take advantage of the characteristics of ammonia, which is a low-cost, low-heat, and high-thermal-conductivity refrigerant, have attracted attention again. ing. Furthermore, since this ammonia absorption refrigerator is heat driven, the power consumption is about one-tenth of that of an electrically driven ammonia compression refrigerator. Effective use of waste heat has the advantage that the energy efficiency of the whole plant is improved and energy saving is achieved. Therefore, technological development and improvement research are actively conducted.
[0003]
Here, a conventional general ammonia absorption refrigerator will be described. As shown in FIG. 1 (where FIG. 1 is a diagram illustrating an embodiment of the present invention), an evaporator 1, It is comprised by the absorber 2, the generator 3, the condenser 4, etc. In operation, the ammonia liquid a is first supplied to the evaporator 1 under a low pressure, and is evaporated by absorbing heat from the fluid b to be cooled, such as brine, to become a low-temperature ammonia gas c. To be cooled. The low-temperature ammonia gas c exiting the evaporator 1 is supercooled by the supercooler 5 after the ammonia liquid sent from the condenser 4 is sent to the absorber 2 and sprayed inside the absorber 2. In contact with the ammonia dilute aqueous solution e sent from the vessel 3, it is absorbed and a concentrated ammonia aqueous solution f is produced. The absorption heat of the ammonia gas c generated at that time to the ammonia dilute aqueous solution e is removed by the cooling water g.
The generated concentrated ammonia aqueous solution f is heat-recovered by exchanging heat with the hot ammonia dilute aqueous solution e sent from the generator 3 by the solution heat exchanger 7 after being pressurized by the solution pump 6, After being heated, it enters the rectifier 8 and is heated by heat energy such as waste heat steam h input from the outside into the generator 3. By this heating, ammonia in the concentrated ammonia aqueous solution f evaporates. However, since ammonia and water are azeotropic mixtures having a large difference in boiling point, the ammonia gas i inevitably contains some water vapor. In order to increase the purity of the ammonia gas i, a rectifier 8 is provided, and measures such as refluxing a part of the ammonia liquid d condensed in the condenser 4 to the partial condenser 9 connected to the rectifier 8 are taken. Yes.
[0004]
As described above, the hot ammonia dilute aqueous solution e, which is the residual liquid after the ammonia gas is evaporated, is sent from the generator 3 to the absorber 2 via the solution heat exchanger 7 and sent from the evaporator 1. The resulting ammonia gas c is absorbed, and an ammonia concentrated aqueous solution f is generated. Thus, the high-concentration ammonia gas i sent from the partial condenser 9 enters the condenser 4 and is cooled and liquefied by the cooling water to become an ammonia liquid d, part of which is returned to the partial condenser 9 as described above. However, the remainder is supercooled in the supercooler 5 by the ammonia gas c sent from the evaporator 1 and then depressurized by the expansion valve 10 to become the low-pressure ammonia liquid a and enter the evaporator 1. . Note that the role of the supercooler 5 is to supercool the ammonia liquid d from the condenser 4 to suppress flushing in which the liquid refrigerant partially evaporates in the pipe before the ammonia liquid d flows into the expansion valve 10. In addition, by stabilizing the flow rate of the ammonia liquid passing through the condenser 4, it is possible to improve the cooling efficiency, that is, the thermal efficiency of the entire system.
[0005]
From the internal pressure, the ammonia absorption refrigerator has a high pressure side consisting of main equipment such as the condenser 4, the rectifier 8 and the generator 3, and a low pressure side consisting of main equipment such as the evaporator 1 and the absorber 2. However, during steady operation, the high pressure side is normally operated under conditions of 1.5 MPa and the low pressure side is normally close to atmospheric pressure, so the pressure difference between the high pressure side and the low pressure side is about 1.5 MPa, which is quite large. Therefore, in FIG. 1, the solution pump 6 for transporting the concentrated ammonia aqueous solution f from the low-pressure side absorber 2 to the high-pressure side rectifier 8 requires a pump having a higher head than the flow rate. Even a low viscosity fluid such as an aqueous ammonia solution requires a pump that can accurately control the flow rate against fluctuations in the head. Gear pumps are inappropriate for such demands, and positive displacement diaphragm pumps are the most suitable particularly for small absorption refrigerators.
[0006]
In addition, since there are the following problems with respect to leakage of ammonia, it is desirable to take all possible measures. That is, ammonia has an irritating odor and is a flammable toxic gas that can burn at 15 to 28% by volume, and its specific weight to air is 0.596, which is considerably lower than air. Therefore, various problems arise in handling from the viewpoint of safety. For example, if ammonia leaks, there is a risk of staying near the ceiling where the ammonia absorption refrigerator is installed and exploding. In addition, since it has a mucosal stimulating action on the human body, there is a risk of causing inflammation in the oral cavity and nasal cavity, and when high-concentration ammonia gas is absorbed, there is a possibility that respiratory irritation may occur due to the stimulation. Furthermore, since a person usually feels an unpleasant odor from an ammonia concentration of about 5 ppm and becomes unpleasant at about 50 ppm, the allowable concentration of ammonia in the working environment is 25 ppm according to the recommended value of the Industrial Hygiene Society. From the viewpoint of safety, it is necessary to pay close attention to the leakage.
[0007]
In ammonia absorption refrigerators, a major cause of the possibility of ammonia leakage is diaphragm damage when a diaphragm pump is used as the solution pump. For example, the diaphragm damage is detected by detecting the diaphragm damage. In order to stop the operation of the ammonia absorption refrigerator, several countermeasures have been proposed in the past as follows.
(1) In the case of a hydraulic diaphragm pump, when the diaphragm has a sandwich structure in which the sensor electrode is sandwiched between two diaphragms, and one of the two diaphragms in the sandwich structure is damaged , A method for detecting breakage of the diaphragm by passing through the diaphragm on which the liquid to be pumped (for example, aqueous ammonia solution) or the working fluid (for example, hydraulic oil) is damaged, or a sensor electrode is provided in the diaphragm In the structure, when the diaphragm is broken, the liquid reaches the sensor electrode and detects the breakage of the diaphragm (for example, see Japanese Patent Application Laid-Open No. 2000-130334).
(2) In a hydraulic diaphragm pump, the diaphragm has a structure in which two diaphragms are overlapped, and a float switch or a pressure switch connected to the gap between the two diaphragms is provided to damage the diaphragm. When liquid leakage occurs, the liquid to be pumped or the working fluid rises through the gap between the diaphragms and reaches the float switch or pressure switch. . In the diaphragm having a structure in which the two diaphragms are overlapped, the diaphragm on the working fluid side displaced by the pressure of the working oil is in direct mechanical contact with the diaphragm on the pumping target liquid side to transmit the displacement. The diaphragm is operated by displacement.
[0008]
[Problems to be solved by the invention]
However, in the conventional countermeasure method (1), it is necessary to specially design the structure of the sensor electrode so that it can be installed in the diaphragm, and the structure of the diaphragm is required to install the sensor electrode in a narrow place in the diaphragm. Is complicated. Further, the diaphragm needs to be specially manufactured to have a configuration including a sensor electrode. As a result, the diaphragm and the sensor electrode are complicated and expensive to manufacture, and the sandwich structure diaphragm is difficult to mold and easily peeled off. In addition, the conventional countermeasure method (2) has a drawback that the float switch and the pressure switch do not accurately detect and operate unless the amount of leakage of the liquid is relatively large, and the installation location of the float switch is under atmospheric pressure. Therefore, if a high-pressure liquid to be pumped or a working fluid leaks, a part of the liquid flushes and becomes vapor, so that the rise in the liquid level is relatively small and the operating accuracy of the float switch, etc. is reduced. There is also a drawback of inviting.
[0009]
Furthermore, conventional hydraulic diaphragm pumps use cylinders, plungers, etc. that require precision machining to pressurize the working fluid fluid, resulting in high manufacturing costs and difficult maintenance. There is. In addition, as a diaphragm pump that avoids the drawbacks of such a hydraulic diaphragm pump, there is a direct acting diaphragm pump that directly mechanically drives the diaphragm not by hydraulic pressure but by a link or the like. In the case of this direct acting diaphragm pump, Since the pressure applied to the diaphragm becomes non-uniform, the diaphragm is easily damaged, and as a result, there is a possibility that the liquid to be pumped cannot be appropriately prevented from leaking to the outside.
Further, in the diaphragm structure of the above-described countermeasure method (2), since the two stacked diaphragms are in mechanical contact with each other to transmit displacement, the diaphragm is worn by friction due to the mechanical contact. There are also drawbacks to damage.
[0010]
The first object of the present invention is to eliminate the disadvantages of the prior art described above, while eliminating the need for precision machining cylinders and plungers, etc., and making the construction as inexpensive as possible while providing a conventional direct acting diaphragm pump and the above-mentioned countermeasures. Providing a diaphragm pump with high environmental safety by appropriately avoiding damage to the diaphragm which has been a problem in the method (2). With it In addition, the diaphragm and detection electrode can be manufactured at a low cost with a simple structure, but it is possible to accurately detect damage to the diaphragm with high operational stability and high environmental safety. There is to do.
First 2 An object of the present invention is to provide a diaphragm damage detection method for a diaphragm pump that can accurately detect damage to the diaphragm and has high environmental safety.
First 3 An object of the present invention is to provide an ammonia absorption type refrigerator capable of avoiding adverse effects on the environment and refrigeration performance even when the diaphragm is damaged when the diaphragm pump is used as a solution pump.
[0011]
[Means for Solving the Problems]
In order to achieve the first object, the first characteristic configuration of the diaphragm pump according to the present invention is that, as described in claim 1, the first diaphragm on the side to be displaced and the first diaphragm on the side in contact with the liquid to be pumped. Between the two diaphragms, there is provided a working fluid reservoir for storing a working fluid liquid that transmits the displacement of the first diaphragm as the displacement of the second diaphragm. Among the liquid to be pumped, the working fluid liquid, and the surrounding medium in contact with the first diaphragm on the opposite side to the working fluid liquid, at least the working fluid liquid has different electrical characteristics from the others. And the surrounding medium is made of gas, and a detection electrode for detecting the electrical characteristics in the working fluid reservoir is installed on the upper side of the working fluid reservoir. In the point.
[0015]
Same two The characteristic configuration of 2 As described above. one In addition to the characteristic configuration of the above, the electrical property detected by the detection electrode is electrical conductivity, and the electrical conductivity decreases in the order of the liquid to be pumped, the working fluid liquid, and the surrounding medium, or The electrical conductivity increases in the order of the liquid to be pumped, the working fluid liquid, and the surrounding medium.
[0016]
Same three The characteristic configuration of 3 As described above. One or First two In addition to the above characteristic configuration, a breakage detecting means for detecting breakage of either the first diaphragm or the second diaphragm based on a detection signal of the detection electrode is provided.
[0017]
Above 2 In order to achieve the above object, the first characteristic configuration of the diaphragm damage detection method of the diaphragm pump according to the present invention is as follows. 4 As described above. one To the second three It is the point which detects breakage of either the said 1st diaphragm or the said 2nd diaphragm based on the detection signal of the said detection electrode with which the diaphragm pump of any one characteristic structure was equipped.
[0018]
Above 3 In order to achieve the object of the present invention, the characteristic configuration of the ammonia absorption refrigerator according to the present invention is as follows. 5 As described in the above, three The diaphragm pump having any one of the features is configured as a solution pump in which the working fluid liquid is formed of water, and the aqueous ammonia solution as the pumping target liquid is conveyed from the low pressure side portion to the high pressure side portion in the flow path. It is in the point provided.
[0019]
The operation and effect will be described below.
According to the first characteristic configuration of the diaphragm pump according to the present invention, when the first diaphragm is driven to be displaced, the displacement of the first diaphragm is the working fluid liquid provided between the first diaphragm and the second diaphragm. The displacement of the second diaphragm is transmitted by the working fluid liquid stored in the reservoir, and the liquid to be pumped in contact with the second diaphragm is pumped by the displacement operation of the second diaphragm.
Therefore, even if the first diaphragm is mechanically driven by a link or the like, the second diaphragm in contact with the liquid to be pumped is displaced by receiving a uniform pressure via the working fluid liquid. Compared to those in which the diaphragm in contact is directly driven by a link or the like in which two overlapping diaphragms are in contact and transmit displacement, the probability of damage to the diaphragm in contact with the liquid to be pumped can be reduced. Environmental safety by avoiding the damage of the conventional direct acting diaphragm pump and the diaphragm (2), which is a problem with conventional direct acting diaphragm pumps, while eliminating the need for cylinders and plungers that require precision machining. Therefore, a diaphragm pump that can increase the performance and achieve the first object can be obtained.
[0020]
And Same one When the first diaphragm among the diaphragms is damaged, the working fluid in the working fluid reservoir passes through the first diaphragm and leaks to the surrounding medium side, and the surrounding medium leaks to the first diaphragm. Since the electric characteristics at a predetermined position in the working fluid reservoir are mixed with the characteristics of the surrounding medium flowing in or the working fluid liquid and the surrounding medium are mixed. The change in the electric characteristic is detected, and the change in the electric characteristic at a predetermined position in the working fluid reservoir is detected by the detection electrode. On the other hand, when the second diaphragm is damaged, the liquid to be pumped flows into the working fluid reservoir and mixes with the working fluid in the working fluid reservoir, so that the electrical characteristics at a predetermined position in the working fluid reservoir are the working fluid. The characteristics of the liquid change to the characteristics of the inflow target liquid to be pumped or the mixed characteristics of the working fluid liquid and the target liquid to be pumped, and the change in the electrical characteristics at a predetermined position in the working fluid liquid reservoir is detected by the detection electrode. . Since the electrical characteristics detected by the detection electrode are different at least between the working fluid liquid and the other liquid to be pumped and the surrounding medium, the pressure pumping liquid is not the working fluid liquid due to the change in the electrical characteristics. It can be determined that any one of the surrounding medium is detected.
[0021]
Therefore, it is possible to detect that one of the first diaphragm and the second diaphragm is damaged due to a change in electrical characteristics at a predetermined position in the working fluid reservoir detected by the detection electrode as described above. When the first diaphragm is broken, the second diaphragm that is in contact with the liquid to be pumped is not damaged. Therefore, the liquid to be pumped does not leak to the outside, and when the second diaphragm is broken, the first diaphragm is Since it is not damaged, the liquid to be pumped flowing into the working fluid liquid reservoir does not leak to the outside, and in any case, environmental safety can be enhanced.
Furthermore, each of the first diaphragm and the second diaphragm can use a general-purpose type diaphragm, and the detection electrode also uses an off-the-shelf type electrode that has been conventionally used for detecting the electrical characteristics of the liquid. Therefore, the diaphragm and the detection electrode can be manufactured at a low cost with a simple structure.
In addition, since diaphragm breakage is detected based on changes in electrical characteristics due to inflow / outflow / mixing of each liquid, etc., into the working fluid reservoir due to diaphragm breakage, for example, the liquid level of the liquid that leaks due to diaphragm breakage Compared with a means such as a float switch for detecting a change, the operation stability is high, and the diaphragm can be accurately detected.
As described above, the diaphragm and the detection electrode can be manufactured at a low cost with a simple structure, but the operational stability is high, the diaphragm can be accurately detected, and the environmental safety is high. 1 Thus, a diaphragm pump that can achieve the above objective is obtained.
[0023]
further, Same one When the first diaphragm is damaged, the gas as the surrounding medium flowing into the working fluid reservoir moves lighter than the working fluid reservoir to the upper side of the working fluid reservoir, and the working fluid A detection electrode, which is installed on the upper side of the liquid reservoir and detects the electrical characteristics at the upper position of the working fluid reservoir, detects a change in the electrical characteristics from the characteristics of the working fluid liquid to the characteristics of the gas flowing in.
Therefore, when the surrounding medium is a gas such as air, the breakage of the first diaphragm can be detected quickly and accurately. Moreover, in this case, the detection electrode installed on the upper side of the working fluid reservoir is installed with a simple structure such as connecting a tube containing the detection electrode to the upper portion of the casing for forming the working fluid reservoir. can do.
[0024]
Same two When the electrical conductivity decreases in the order of the liquid to be pumped, the working fluid liquid, and the surrounding medium, the electrical conductivity in the working fluid reservoir detected by the detection electrode becomes the working fluid liquid. If it falls from the corresponding value, it can be detected that the first diaphragm is broken and the surrounding medium flows into the working fluid reservoir, and conversely, the detected value of the electrical conductivity corresponds to the working fluid liquid. If it rises from, it can be detected that the second diaphragm is broken and the liquid to be pumped flows into the working fluid reservoir.
On the other hand, if the electrical conductivity increases in the order of the liquid to be pumped, the working fluid liquid, and the surrounding medium, if the detected value of the electrical conductivity in the working fluid reservoir rises from the value corresponding to the working fluid liquid If the first diaphragm is broken and it can be detected that the surrounding medium is flowing into the working fluid reservoir, conversely, if the detected value of the electrical conductivity decreases from the value corresponding to the working fluid, the second It can be detected that the diaphragm is damaged and the liquid to be pumped flows into the working fluid reservoir.
Therefore, it is detected while accurately identifying whether the first diaphragm is damaged or the second diaphragm is damaged by a simple detection means for detecting a change in electrical conductivity in the working fluid reservoir with the detection electrode. be able to.
In particular, when the electric conductivity decreases in the order of the liquid to be pumped, the working fluid liquid, and the surrounding medium, the diaphragm suitable for an application in which the conductive fluid is transported as the liquid to be pumped by the diaphragm pump according to the present invention. A pump can be realized.
[0025]
Same three According to this characteristic configuration, the breakage detecting means detects breakage of either the first diaphragm or the second diaphragm based on the detection signal of the detection electrode.
Accordingly, the breakage detecting means provided in the diaphragm pump detects the breakage of either the first diaphragm or the second diaphragm. For example, the operation of the diaphragm pump is forcibly stopped based on the breakage detection signal of the diaphragm. Or an alarm means such as a buzzer may be activated to take appropriate measures such as notifying the operator of the occurrence of diaphragm damage.
[0026]
According to the characteristic configuration of the diaphragm damage detection method for the diaphragm pump according to the present invention, the first one To the second three Based on the detection signal of the detection electrode provided in the diaphragm pump having any one of the above-described features, the breakage of either the first diaphragm or the second diaphragm is detected.
Therefore, it is possible to detect damage to either the first diaphragm or the second diaphragm based on the detection information of the detection electrode by connecting an external detection device or the like to the detection electrode provided in the diaphragm pump. The diaphragm pump itself can be provided with a use condition with a degree of freedom such that a detection device is configured by a general-purpose microcomputer or the like while being simply configured as much as possible by providing a detection electrode.
[0027]
According to the ammonia absorption refrigerator according to the present invention, the diaphragm pump provided as a solution pump uses water as a working fluid liquid, and supplies an aqueous ammonia solution as a pumping target liquid from a low pressure side portion in the flow path to a high pressure. Transport to side part.
Accordingly, when the first diaphragm is damaged while the aqueous ammonia solution is being transported, the working fluid liquid in the working fluid liquid reservoir flows out to the outside, but since the working fluid liquid is water, Even if it leaks, there is almost no risk of adversely affecting the external environment. On the other hand, when the second diaphragm is broken, the working fluid liquid in the working fluid reservoir is mixed into the liquid to be pumped, but the working fluid liquid that is water is mixed in the aqueous ammonia solution. A slight change does not significantly change the performance of the ammonia refrigeration cycle, so when using the diaphragm pump as a solution pump, avoiding adverse effects on the environment and refrigeration performance even if the diaphragm is damaged. It is possible to obtain an ammonia absorption refrigerator that can be used.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Embodiments of a diaphragm pump according to the present invention and an ammonia absorption refrigerator equipped with the diaphragm pump will be described with reference to the drawings.
[0029]
Before describing the diaphragm pump according to the present invention, a general direct acting diaphragm pump will be described as a comparative example. As shown in FIG. 5 (a), when the connecting link 13 interlocked with the crankshaft 12 is pushed leftward, the diaphragm 14 connected to the connecting link 13 is pushed leftward, whereby the suction check valve 15 Is closed, the discharge check valve 16 is opened, and the liquid to be pumped j is discharged downward.
On the other hand, as shown in FIG. 5 (b), when the connecting link 13 is pulled to the right, the diaphragm 14 is pulled to the right, the suction check valve 15 is opened, and the discharge check valve 16 is closed. Liquid j flows from above. Hereinafter, by repeating the above operation, the liquid to be pumped j is circulated from above to below while being pressurized. As described above, this direct acting diaphragm pump has a drawback that non-uniform pressure is applied to the portion of the diaphragm 14 to which the connecting link 13 is connected, and damage is likely to occur.
[0030]
Next, the configuration and operation of the diaphragm pump according to the present invention will be described with reference to FIG. A first diaphragm 18 is connected to a connecting link 13 provided so as to be interlocked with the movement of the crankshaft 12, and a second diaphragm 19 is provided on the opposite side of the first diaphragm 18 from the connecting link 13 at an interval. The working fluid liquid k (specifically, water) is sealed in a portion (working fluid reservoir ED) surrounded by the first diaphragm 18, the second diaphragm 19 and the casing 20, and the working fluid of the second diaphragm 19 is sealed. The liquid to be pumped j (specifically, an aqueous ammonia solution) is in contact with the side opposite to the side in contact with the liquid k. That is, the working fluid liquid that transmits the displacement of the first diaphragm 18 as the displacement of the second diaphragm 19 between the first diaphragm 18 on the displacement driven side and the second diaphragm 19 on the side in contact with the pumping target liquid j. A working fluid reservoir ED is provided. Note that air as a surrounding medium is in contact with the first diaphragm 18 on the side opposite to the working fluid liquid k.
[0031]
Accordingly, as shown in FIG. 2 (a), when the connecting link 13 is pushed to the left and the first diaphragm 18 is pushed to the left in conjunction with this, the working fluid liquid k increases the pressure to the left. Upon receipt, the left diaphragm 19 is pushed leftward, and the second diaphragm 19 is pushed leftward. As a result, the suction check valve 15 is closed, the discharge check valve 16 is opened, and the pumping target liquid j is discharged downward. On the contrary, as shown in FIG. 2 (b), when the connecting link 13 is pulled rightward and the first diaphragm 18 is pulled rightward, the working fluid liquid k receives the rightward pulling force and moves rightward. And the second diaphragm 19 is pulled to the right. As a result, the suction check valve 15 is opened, the discharge check valve 16 is closed, and the liquid to be pumped j flows from above. Hereinafter, by repeating the above operation, the liquid to be pumped j can be circulated from above to below while being pressurized.
[0032]
A detection electrode (hereinafter referred to as a sensor electrode) 21 that detects electrical characteristics at a predetermined position (upper side position) in the working fluid reservoir ED is installed on the upper side of the working fluid reservoir ED. Specifically, a pipe 20a containing the sensor electrode 21 is connected to the upper part of the casing 20 in a state where it communicates with the working fluid reservoir ED.
Each of the liquid to be pumped j, the working fluid liquid k, and the surrounding medium (air) has the different electrical characteristics. Specifically, the electrical property detected by the sensor electrode 21 is electrical conductivity (μS / cm), and the electrical conductivity is in the order of the liquid to be pumped j, the working fluid liquid k, and the surrounding medium (air). It is low.
[0033]
Furthermore, based on the detection signal of the sensor electrode 21, a breakage detecting means 22 for detecting breakage of either the first diaphragm 18 or the second diaphragm 19, and a pump driving operation controlled by the breakage detecting means 22 A motor 23 is provided.
[0034]
When neither the first diaphragm 18 nor the second diaphragm 19 is damaged, the sensor electrode 21 detects the electrical conductivity of water that is the working fluid liquid k. At this time, for example, when water of a tap water class is used, an electrical conductivity of about 100 to 150 μS / cm is detected. The water used as the working fluid liquid k is detected by the sensor electrode 21 because the air or the pumped liquid j enters the working fluid reservoir ED due to the damage of the first diaphragm 18 or the second diaphragm 19. As long as the electrical conductivity is sufficiently large with respect to the electrical conductivity of water, groundwater having an electrical conductivity of about 500 μS / cm can be used from pure water.
[0035]
When the first diaphragm 18 is damaged, as shown in FIG. 3 (a), the working fluid liquid k leaks to the outside, and instead air flows in and accumulates at the upper position of the working fluid reservoir ED. 21 is in contact with air, and the detected electrical conductivity is very small (see FIG. 4). Further, when the second diaphragm 18 is damaged, as shown in FIG. 3B, the liquid to be pumped j (an aqueous ammonia solution having an electric conductivity of, for example, about 1200 μS / cm) flows into the working fluid reservoir ED. Since it mixes with the working fluid liquid k, the electrical conductivity detected by the sensor electrode 21 becomes very large (see FIG. 4). If the electrical conductivity detected by the sensor electrode 21 is greater than the electrical conductivity of the water by a predetermined value or more, the second diaphragm 19 is damaged. On the contrary, if the detected electrical conductivity is smaller than the electrical conductivity of the water by a predetermined value or more, it is determined that the first diaphragm 18 is damaged, and one of the diaphragms is damaged. Is detected, the pump driving motor 23 is stopped. At the same time, an alarm device (not shown) is activated to notify the occurrence of a trouble and prompt appropriate measures such as stopping the operation of the ammonia absorption refrigerator. As a result, appropriate maintenance such as early replacement of a damaged diaphragm becomes possible.
[0036]
The ammonia absorption type refrigerator uses ammonia as a refrigerant and water as an absorbent, and the configuration and operation thereof are as already described with reference to FIG. The diaphragm pump 6 constitutes the working fluid liquid k with water, and absorbs ammonia as the solution pump 6 that conveys the aqueous ammonia solution as the pumping target liquid j from the low pressure side portion to the high pressure side portion in the flow path. It is equipped with a type refrigerator. Specifically, the solution pump 6 conveys the concentrated ammonia aqueous solution from the absorber 2 to the rectifier 8.
[0037]
Next, an embodiment of a diaphragm damage detection method for a diaphragm pump according to the present invention will be described.
That is, this diaphragm damage detection method of the diaphragm pump detects damage of either the first diaphragm 18 or the second diaphragm 19 based on the detection signal of the sensor electrode 21 provided in the diaphragm pump.
Specifically, as described above, the breakage detecting means 22 provided in the diaphragm pump is used to detect the breakage of either the first diaphragm 18 or the second diaphragm 19 based on the detection signal of the sensor electrode 21. In addition to this, in the case of a diaphragm pump that does not include the breakage detection means 22, the sensor electrode 21 is connected to a general-purpose controller such as a microcomputer. It can be configured to detect the breakage of either the first diaphragm 18 or the second diaphragm 19.
[0038]
As is clear from the above description, the diaphragm pump according to the present invention is effective for pressurizing and conveying a liquid to be pumped that may release a gas having a risk of toxicity or ignition when leaking. It will be a thing. In particular, it is effective for use as a solution pump for conveying a concentrated aqueous ammonia solution from an absorber to a rectifier in a small ammonia absorption refrigerator.
[0039]
[Another embodiment]
In the above embodiment, the case where the electrical characteristic detected by the detection electrode 21 is electrical conductivity has been described. However, other than electrical conductivity, for example, capacitance may be used.
Moreover, when the detection electrode 21 detects electrical conductivity, in the said embodiment, although comprised so that electrical conductivity might become low in order of the pumping target liquid j, the working fluid liquid k, and the surrounding medium, conversely, You may comprise so that electrical conductivity may become high in order of the pumping target liquid j, the working fluid liquid k, and the surrounding medium.
Furthermore, as the electrical characteristics, a plurality of electrical characteristics may be detected instead of one electrical characteristic. In this case, for example, one electrical characteristic (for example, electrical conductivity) for one set (for example, the pressure target liquid j and the working fluid liquid k) of the pressure target liquid j, the working fluid liquid k, and the surrounding medium. In each of the liquids and media, the different sets (for example, the working fluid liquid k and the surrounding medium) have different characteristics in other electrical characteristics (for example, capacitance). It becomes possible to set the electrical characteristics appropriately in conformity with the characteristics.
[0040]
In the above embodiment, each of the liquid to be pumped j, the working fluid liquid k, and the surrounding medium has different electrical characteristics, and it is determined whether the first diaphragm 18 or the second diaphragm 19 is damaged. However, other than this, at least the working fluid liquid k has different electrical characteristics from those of the other liquids (pressure-feeding liquid j and surrounding medium), and either the first diaphragm 18 or the second diaphragm 19 is damaged. May be detected.
[0041]
In the above embodiment, the detection electrode 21 is installed on the upper side of the working fluid reservoir ED. However, for example, the detection electrode 21 may be installed on both the upper side and the lower side of the working fluid reservoir ED. Thereby, for example, the specific gravity of the pumping target liquid j is larger than the specific gravity of the working fluid liquid k, and the pumping target liquid j that has flowed into the working fluid liquid reservoir ED due to the breakage of the second diaphragm 19 is Even if the detection electrode 21 installed on the upper side of the working fluid reservoir ED cannot properly detect the inflow of the pressure-feed target liquid j when it accumulates in the lower portion, the detection provided on the lower portion of the working fluid reservoir ED. The electrode 21 can appropriately detect the inflow of the liquid to be pumped j.
[0042]
Moreover, in the said embodiment, although the diameter of the 2nd diaphragm 19 was formed identically with the diameter of the 1st diaphragm 18, for example, by forming the diameter of the 2nd diaphragm 19 smaller than the diameter of the 1st diaphragm 18, High pressure can be generated for the second diaphragm 19 while reducing the drive amount of the connecting link 13 that drives the displacement of the first diaphragm 18.
[0043]
In the above embodiment, the case where the diaphragm pump is applied to a solution pump for conveying an aqueous ammonia solution used in an ammonia absorption refrigerator has been described. However, the diaphragm pump according to the present invention conveys various liquids to be pumped other than the aqueous ammonia solution. It can be applied to a diaphragm pump for use. In addition, when using the diaphragm pump which concerns on this invention for uses other than an ammonia absorption refrigerating machine, for example, you may make working fluid liquid into media (working oil etc.) other than water.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a refrigeration cycle of an ammonia absorption refrigerator
FIG. 2 is a side view illustrating the configuration and operation of a diaphragm pump according to the present invention.
FIG. 3 is a side view showing leakage due to damage to the diaphragm of the diaphragm pump according to the present invention.
FIG. 4 is a graph showing detected values of electrical conductivity.
FIG. 5 is a side view illustrating the configuration and operation of a general direct acting diaphragm pump.
[Explanation of symbols]
6 Solution pump
18 First diaphragm
19 Second diaphragm
21 Detection electrode
22 Damage detection means
ED Working fluid reservoir

Claims (5)

A working fluid liquid that stores a working fluid liquid that transmits the displacement of the first diaphragm as the displacement of the second diaphragm between the first diaphragm on the displacement driven side and the second diaphragm in contact with the liquid to be pumped. A reservoir is provided , and at least the working fluid liquid among the liquid to be pumped, the working fluid liquid, and the surrounding medium contacting the first diaphragm on the side opposite to the working fluid liquid A diaphragm pump having different electrical characteristics, wherein the surrounding medium is composed of gas, and a detection electrode for detecting the electrical characteristics in the working fluid reservoir is installed on the upper side of the working fluid reservoir . The electrical property detected by the detection electrode is electrical conductivity, and the electrical conductivity decreases in the order of the liquid to be pumped, the working fluid liquid and the surrounding medium, or the liquid to be pumped and the working fluid. The diaphragm pump according to claim 1 , wherein the diaphragm is configured so that electric conductivity increases in the order of the liquid and the surrounding medium. The diaphragm pump according to claim 1 or 2 , further comprising a breakage detecting means for detecting breakage of either the first diaphragm or the second diaphragm based on a detection signal of the detection electrode. Based on the detection signal of the detection electrode with a diaphragm pump according to any one of claims 1 to 3, wherein the first diaphragm and the second one of the diaphragm damage detection method of the diaphragm pump for detecting the breakage of the diaphragm . The diaphragm pump according to any one of claims 1 to 3 , wherein the working fluid liquid is composed of water, and an aqueous ammonia solution as the pressure feed liquid is conveyed from a low-pressure side portion to a high-pressure side portion in the flow path. An ammonia absorption refrigerator equipped as a solution pump.

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