JP7849876B2 - Leak detection device and fixed case - Google Patents

Description

This invention relates to a leak detection device and a fixed case.

Patent Document 1 (Japanese Patent Application Publication No. 2011-95249) discloses a leak detection device capable of outputting a detection signal at a suitable timing.
The leak detection device described in Patent Document 1 has a leak detection unit comprising an introduction section for introducing leaked liquid, a light projection means for irradiating light toward the introduction section, a light receiving means for receiving light from the light projection means via the introduction section, and a detection means for detecting leaked liquid based on the amount of light received by the light receiving means, and outputs a detection signal to the outside based on the leak detection result of the leak detection unit, wherein the leak detection device is installed with a gap between it and the floor surface, and the leak detection unit has a first leak detection unit and a second leak detection unit provided at different positions on the lower surface of the leak detection device, the first leak detection unit being positioned closer to the periphery on a line connecting the center and periphery of the lower surface of the leak detection device, the second leak detection unit being provided in a recess provided at a position away from the periphery of the lower surface of the leak detection device, and the output control means being characterized in that it outputs a detection signal when the second leak detection unit detects leaked liquid, and outputs a detection signal after a predetermined time when the first leak detection unit detects leaked liquid.

Patent Document 2 (Japanese Patent Publication No. 2021-148676) discloses a liquid leak detection device for a hydraulic device, and in particular, a technology is disclosed in which leaked liquid is introduced into a leak storage case capable of storing a predetermined volume, the discharged liquid after a predetermined volume of liquid has been stored in the leak storage case is detected by a leak sensor, and the leak storage case is provided with a storage volume changing mechanism to change the predetermined volume.
The liquid leak detection device for a hydraulic device described in Patent Document 2 is characterized by comprising: a leak storage case in which liquid leaked from the hydraulic device is introduced through an inlet port and can be stored in a predetermined predetermined capacity, and which has a discharge port for discharging liquid when the predetermined capacity of liquid has been stored; a detection case in which the discharged liquid from the discharge port is guided and which is equipped with a leak sensor for detecting the presence or absence of discharged liquid; a storage capacity changing mechanism provided in the leak storage case for changing the predetermined capacity; and a control unit that determines the presence or absence of discharged liquid by the leak sensor.

Patent Document 3 (Japanese Patent Publication No. 2022-35523) discloses a liquid leakage port attachment device that can be easily attached at the installation site to an existing hydraulic cylinder device that does not have a liquid leakage port.
The liquid leak port attachment device described in Patent Document 3 comprises a cylinder tube, a piston, a piston rod, a rod bush, a rod-side cover, and a head-side cover, and is attachable to a hydraulic cylinder device in which the piston rod extends through the rod bush. The liquid leak port attachment device comprises an inner circumference portion on which the portion of the piston rod extending from the rod bush can slide, a fitting portion into which the outer circumference surface of the rod bush can be fitted, a dust seal mounted on the inner circumference portion, an O-ring mounted on the fitting portion, a liquid leak passage that guides the leaked liquid from the extended portion through the space between the dust seal and the O-ring, and a liquid leak port at the end of the liquid leak passage. The liquid leak port attachment device is attachable to a hydraulic cylinder device.

Patent document 4 (Japanese Patent Publication No. 2021-143690) discloses a remote condition monitoring device for a hydraulic cylinder that enables long-term operation using a dry cell power source.
The remote condition monitoring device described in Patent Document 4 is a remote condition monitoring device for monitoring the state of a hydraulic cylinder, comprising: a sensor that detects the dynamic and static state of the hydraulic cylinder and outputs a detection signal; a wireless communication circuit that receives the detection signal from the sensor and transmits a wireless signal to an information terminal and receives a wireless signal from the information terminal; a low-voltage power supply that supplies power to the wireless communication circuit; a boost circuit connected to the low-voltage power supply and boosting the voltage of the low-voltage power supply; a switching circuit that selectively supplies the power boosted by the boost circuit to the sensor; and a control circuit connected to the low-voltage power supply that receives a hydraulic cylinder operation signal and controls the switching circuit, wherein the control circuit repeatedly turns on and off the switching circuit at a predetermined cycle when the hydraulic cylinder operation signal is on, and turns off the switching circuit when the hydraulic cylinder operation signal is off, and the on control of the switching circuit includes a predetermined on time.

Patent Document 5 (Japanese Patent Publication No. 2006-300956) discloses a leak sensor that can easily identify the location of a leak when a leak abnormality occurs, by installing the leak sensor at the lowest part of a system such as the floor or a leak containment section.
In the leak sensor described in Patent Document 5, the leak sensor is installed in the internal space of the leak containment section, and an alarm means including a sound-emitting means having a resonator is provided within a spatial range that includes at least one of the internal space of the leak containment section and/or the space above the leak containment section, relative to the installation position of the leak sensor. When the leak sensor detects a sensor abnormality, the sound-emitting means having a resonator amplifies the sound of an audible frequency emitted from the sound-emitting means by the resonator so that the installation position of the leak sensor can be identified, distinguishing it from leak sensors installed outside the spatial range.

Patent document 6 (Japanese Patent Publication No. 2016-102771) discloses a leak sensor that can be installed in narrow gaps and can detect even small amounts of leaks.
The leak sensor described in Patent Document 6 is a leak sensor that detects liquid by detecting a change in refractive index when a sensor part formed on the curved portion of an optical fiber comes into contact with the liquid, and comprises a holder for holding the sensor part and a liquid collection means for collecting the liquid to be detected and wetting the sensor part.

Patent document 7 (Japanese Patent Application Publication No. 2012-233744) discloses a leak detection device that makes it possible to easily introduce liquid into the liquid introduction section.
The leak detection device and base for the leak detection device described in Patent Document 7 comprises a sensor body portion having a light-emitting element and a light-receiving element in a light-transmitting case, and a light-transmitting base portion interposed between the detection-side end face of the case and the installation surface, wherein the base portion is provided with a contact surface that is in close contact with the detection-side end face of the case, and a liquid introduction portion recessed in the back side portion of the contact surface, and the leak detection device detects the presence or absence of liquid in the liquid introduction portion by receiving light emitted from the light-emitting element toward the detection-side end face of the case via the liquid introduction portion, wherein the base portion has an air hole that penetrates from the liquid introduction portion to the case-side end face of the base portion, and at least one of the case-side end face of the base portion and the detection-side end face of the case has a groove portion that extends from the air hole to the outer edge of the contact surface, avoiding the optical path of the light emitted from the light-emitting element.

Patent document 8 (Japanese Patent Application Publication No. 2011-215039) discloses a leak sensor capable of appropriately detecting various types of liquids.
The leak sensor described in Patent Document 8 comprises a sensor body having a light-transmitting section having a detection surface directed toward the submerged surface through a gap, a light-emitting section that emits light toward the detection surface, and a light-receiving section that receives light emitted from the light-emitting section and reflected or transmitted by the detection surface, and outputs a light-receiving signal according to the amount of light received, and is equipped with an adjustment section that can adjust the height of the detection surface relative to the submerged surface.

Patent document 9 (Japanese Patent Application Publication No. 2005-164366) discloses a leak detector that, when the sensor unit is installed on the sensor installation surface, eliminates the need for mounting brackets, thereby reducing installation time and enabling reliable detection of leaked liquid on the sensor installation surface.
The leak detector described in Patent Document 9 is a leak detector that detects leaks based on a leak detection output signal that is output when one electrode and the other electrode provided on a sensor unit installed on a sensor installation surface are short-circuited by leaked liquid. The sensor unit is provided with mounting holes for attaching a sensor mounting member provided on the sensor installation surface when it is installed on the sensor installation surface, and the one electrode and the other electrode are exposed on the sensor installation surface side of the sensor unit, and is characterized in that it detects leaked liquid on the sensor installation surface.

Japanese Patent Publication No. 2011-95249 Japanese Patent Publication No. 2021-148676 Japanese Patent Publication No. 2022-35523 Japanese Patent Publication No. 2021-143690 Japanese Patent Publication No. 2006-300956 Japanese Patent Publication No. 2016-102771 Japanese Patent Publication No. 2012-233744 Japanese Patent Publication No. 2011-215039 Japanese Patent Publication No. 2005-164366

As described above, the leak detection device described in Patent Document 1 is described as having multiple leak detection units. Furthermore, Patent Document 2 describes the storage of leaked liquid. Patent Document 3 describes a device equipped with a leak port that has a leak flow path.
Patent document 4 describes a remote status monitoring device that can be monitored remotely. Patent document 5 describes detecting abnormalities using a sound-emitting means having a resonator.

Patent document 6 describes a leak sensor using a sensor portion formed from the curved portion of an optical fiber. Patent document 7 describes a leak detection device equipped with a groove portion extending from an air vent to the outer edge of the contact surface.

Patent document 8 describes an adjustment unit that allows adjustment of the height of the detection surface. The adjustment unit describes a technique for adjusting the height of the detection surface relative to the submerged surface by changing the protruding length of a protruding part as needed. Patent document 9 describes a leak detector provided with mounting holes for screwing in stud bolts.

In recent years, there has been a growing demand for leak detection devices that are easy to use and suitable for various applications, rather than requiring multiple sensors or different types of leak detection devices. Furthermore, there is a need for leak detection devices that are easy to install and whose detection can be easily verified.
In addition, while leaks from water are less likely to cause problems, oil leaks can occur if the surrounding environment or the oil itself is hot. As a result, heat-resistant leak detection devices are required.

The main objective of the present invention is to provide a leak detection device and a fixing case that can be easily fixed to a detection location and can detect a predetermined amount of leakage.
The main objective of the present invention is to provide a leak detection device and a fixing case that are heat-resistant, can be easily fixed to a detection location, and can detect a predetermined amount of leak at low cost.

(1)
A fixed case conforming to one aspect is a fixed case for fixing the detection part of a leak detection sensor, which includes a cylindrical threaded portion, a light-emitting element, a light-receiving element, and a prism lens, with the detection part of the prism lens facing downwards, with a cone shape formed at the end of the cylindrical shape, and is made of a cylindrical shape having a predetermined height, and includes a through hole in the shaft of the cylinder, a fitting portion that fits with the threaded portion at the top of the through hole, an air through hole provided from the side of the cylinder to the through hole, a leg portion provided on the back surface, a magnet provided on the leg portion, and a gap-forming portion at the bottom of the through hole that forms a predetermined gap between it and the cone-shaped detection part.

In this case, the leak detection sensor can be easily fixed to the fitting portion, and a gap is created between the conical portion of the leak detection sensor and the fixing case by the gap-forming portion provided in the fixing case, so that the liquid or oil in the leg portion can be guided to the prism lens by capillary action.
Furthermore, by adjusting a predetermined gap, the detection level for the viscosity and quantity of the liquid or oil can be adjusted. In addition, the presence of an air through-hole ensures that capillary action is reliably generated.
Furthermore, by equipping the legs with magnets, it can be easily attached to the detection location. Also, to explore potential detection locations, it can be easily moved by magnetic force simply by placing it on a flat surface.
Furthermore, the gap-forming portion includes cases where the inner diameter of the through-hole is maintained, cases where the inner diameter of the through-hole is changed, and cases where the inner diameter of the through-hole is changed by a separate component.

(2)
The fixing case according to the second invention is a fixing case relating to one aspect, wherein the cylindrical shape has a mounting surface formed thereon and further includes a magnet provided on the mounting surface, and the legs may consist of a pair of fan shapes.

In this case, since a magnet is provided on the cylindrical mounting surface of the fixed case, the side of the fixed case can be easily attached to the detection location. Furthermore, since the legs consist of a pair of fan-shaped parts, it is possible to achieve the effect of guiding leaked liquid or oil to the gap-forming part and the detection part.
The mounting surface may be a surface formed by a D-cut, or any other arbitrary mounting surface.

(3)
The fixing case according to the third invention is a fixing case relating to one aspect, in which the gap forming portion is made of a separate member and may have a cylindrical portion that fits inside the through hole and a truncated inverted cone portion on the inner surface of one end of the cylindrical portion.

In this case, the gap-forming portion may be made of a separate component. Furthermore, because it has a cylindrical portion that fits inside the through-hole and a truncated inverted cone portion on the inner surface of one end of the cylindrical portion, a gap is provided between the detection portion of the conical leak detection sensor and the fixed case. Therefore, the liquid or oil in the leg portion can be guided to the prism lens of the detection portion by capillary action.

(4)
The fixing case according to the fourth invention is a fixing case relating to one aspect, in which the gap forming portion is formed on the lower side of the through hole, and the inner surface of the lower side of the through hole may have a truncated inverted cone portion.

In this case, the gap-forming portion is formed on the lower side of the through-hole, and has a truncated inverted cone portion on the inner surface of the lower side of the through-hole. Therefore, a gap is provided between the conical detection portion of the leak detection sensor and the fixed case, allowing the liquid or oil in the leg portion to be guided to the prism lens of the detection portion by capillary action.

(5)
The fixing case according to the fifth invention is a fixing case relating to one aspect, wherein the gap forming portion is formed on the lower side of the through hole, and the inner surface on the lower side of the through hole may have a through hole portion with a diameter smaller than the diameter of the through hole.

In this case, the gap-forming portion is formed on the lower side of the through-hole, and the inner surface of the lower side of the through-hole has a through-hole portion with a diameter smaller than the diameter of the through-hole itself. Therefore, a gap is provided between the detection portion of the conical part of the leak detection sensor and the fixed case, allowing the liquid or oil in the leg portion to be guided to the prism lens of the detection portion by capillary action.

(6)
The fixed case according to the sixth invention is a fixed case according to the third to fifth inventions, in which the gap-forming portion may be made of a surface material that absorbs light or a material that transmits light.

In this case, since the gap-forming portion is made of a surface material that absorbs light or a material that transmits light, the detection sensitivity of the prism lens, which is the detection portion, can be improved.

(7)
A leak detection device according to other specifications includes a leak detection sensor comprising a cylindrical threaded portion having a conical shape at the end of the cylindrical shape, a light-emitting element, a light-receiving element, and a prism lens; and a fixing case having a predetermined height and a cylindrical shape with a mounting surface, comprising a through hole in the shaft of the cylinder, a fitting portion at the top of the through hole that fits with the threaded portion, an air through hole provided from the side of the cylinder to the through hole, a leg portion provided on the back surface, a magnet provided on the leg portion, and a gap-forming portion at the bottom of the through hole that forms a predetermined gap between it and the conical shape, wherein the detection portion of the prism lens of the leak detection sensor is facing downwards, and the threaded portion of the leak detection sensor is fixed to the fitting portion of the fixing case.

In this case, the leak detection sensor can be easily fixed to the fitting part, and a gap is provided between the detection part of the conical part of the leak detection sensor and the fixing case by the gap-forming part provided in the fixing case, so that the liquid or oil in the leg part can be guided to the prism lens of the detection part by capillary action.
Furthermore, by adjusting a predetermined gap, the detection level for the viscosity and quantity of the liquid or oil can be adjusted. In addition, the presence of an air through-hole ensures that capillary action is reliably generated.
Furthermore, by equipping the legs with magnets, it can be easily attached to the detection location.

This is an external perspective view showing an example of a leak detection device according to this embodiment. This is a schematic diagram showing an example of a plan view of a leak detection device. This is a schematic diagram showing an example of a side view of a leak detection device. This is a schematic diagram showing an example of a bottom view (rear view) of a leak detection device. This is a schematic diagram showing an example of the D-cut surface of a leak detection device. This is a schematic diagram showing an example of a cross-section along line A-A of a leak detection device. This is a schematic perspective view showing how a leak detection sensor is fixed to a fixed case of a leak detection device, and a diagram illustrating the principle of the leak detection sensor. This is a schematic perspective view showing an example of the bottom (back) side of a fixed case. Figures 1 to 8 show schematic assembly cross-sectional views illustrating other examples of leak detection devices. Figure 9 is a partially enlarged schematic diagram of another example of the leak detection device. These are schematic assembly cross-sectional views showing yet another example of the leak detection device shown in Figures 1 to 8. Figure 11 is a partially enlarged schematic diagram of another example of the leak detection device. Figures 1 to 8 show schematic assembly perspective views illustrating yet another example of the leak detection device. These are schematic assembly cross-sectional views showing yet another example of the leak detection device shown in Figures 1 to 8. Figure 14 is a partially enlarged schematic diagram of another example of the leak detection device. This is a schematic cross-sectional view showing another example of the liquid guide section. This is a schematic side view showing another example of the legs of a fixed case for a leak detection device. This is a schematic bottom view showing another example of the legs of a fixed case for a leak detection device. This is a schematic cross-sectional view showing another example of the legs of a fixed case for a leak detection device.

The embodiments of the present invention will be described below with reference to the drawings. In the following description, identical parts will be denoted by the same reference numeral. Furthermore, in cases where the same reference numeral is used, their names and functions are also identical. Therefore, detailed descriptions of them will not be repeated.

(Leak detection device 100)
Figure 1 is an external perspective view showing an example of a leak detection device 100 according to this embodiment.
As shown in Figure 1, the leak detection device 100 consists of a fixed case 200 and a leak detection sensor 500. As shown in Figure 1, a wire 550 is provided from the leak detection sensor 500, and leaks can be detected by changes in power. Note that the illustration of the wire 550 will be omitted below.

Figure 2 is a schematic diagram showing an example of a plan view of the leak detection device 100, Figure 3 is a schematic diagram showing an example of a side view of the leak detection device 100, and Figure 4 is a schematic diagram showing an example of a bottom view (rear view) of the leak detection device 100. Furthermore, Figure 5 is a schematic diagram showing an example of a D-cut surface 240 of the leak detection device 100, and Figure 6 is a schematic diagram showing an example of a cross-section along line A-A of the leak detection device 100.
Figure 7 is a schematic perspective view showing the leak detection sensor 500 fixed to the fixed case 200 of the leak detection device 100, and a diagram illustrating the principle of the leak detection sensor 500. Figure 8 is a schematic perspective view showing an example of the bottom side (back side) of the fixed case 200.

As shown in Figures 2 to 8, the leak detection device 100 consists of a two-stage, substantially cylindrical structure comprising a leak detection sensor 500 and a fixed case 200. The fixed case 200 has a through hole 210 formed in the substantially cylindrical shaft portion, and also has a D-cut surface 240 formed therein.
As shown in Figure 7, the leak detection sensor 500 is inserted into the through hole 210 of the fixed case 200 in the direction of the arrow, fitted in as described later, and fixed in place.
The leak detection sensor 500 is a reflective type that detects the presence of light received by the light-receiving element when light emitted from the internal light-emitting element undergoes total internal reflection at the interface between the prism lens and the gas, due to the large angle of refraction between the prism lens and the gas in a gas. Therefore, when a liquid or oil is present on a flat surface, the angle of refraction decreases, causing the light emitted from the internal light-emitting element to enter the oil or liquid through the prism lens, and the amount of light returning to the light-receiving element is attenuated by a predetermined amount. As a result, the presence of oil or liquid (water) is detected.
Furthermore, when the leak detection sensor 500 is fixed in the through-hole 210 of the fixed case 200, a gap-forming portion 213 is formed at the bottom of the through-hole 210, as shown in Figure 6. The gap-forming portion 213 is preferably made of a surface material that absorbs light or a material that transmits light, or a light-absorbing material may be applied to it.

The leak detection sensor 500 operates within a temperature range of -40°C to +125°C and is waterproof. The power supply voltage is between DC 5 volts and DC 30 volts.
The leak detection sensor 500 in this embodiment is mainly made of a fluororesin, but is covered with an aluminum cover for heat resistance, and the leak detection sensor 500 is approximately 30 mm in diameter and 10 mm in height.

As shown in Figures 6 and 7, the leak detection sensor 500 has a cylindrical shape 510 and a conical shape 520 at the end of the cylindrical shape 510. A threaded portion 580 is formed on a part of the cylindrical shape 510, and a threaded portion 280 that can be fitted with the threaded portion 580 is formed in the through hole 210 of the fixing case 200.
Furthermore, the fixed case 200 is mainly made of aluminum and has dimensions of 45 mm in diameter and 16 mm in height.

The fixed case 200 is provided with a pair of fan-shaped legs 220 on its bottom side. A magnet 350 is embedded in one side of the pair of legs 220.
Two φ3.4 fixing holes 260 are formed from the top surface to the bottom surface of the fixing case 200.
Furthermore, a magnet 350 is also provided on the D-cut surface 240 of the fixed case 200. The magnet 350 on the D-cut surface 240 allows the leak detection device 100 to be easily attached to a metal surface on which it is erected.

Furthermore, two M3 screw holes 265 for fixing are formed in the D-cut surface 240 of the fixing case 200.
Furthermore, an air through-hole 255 is formed from the side of the fixed case 200 to the through-hole 210. As a result, the air through-hole 255 can be used to fill the escape route for gas when liquid is lifted in the gap-forming portion 213 formed below the through-hole 210.

(Example 1)
A liquid detection experiment was conducted using the leak detection device 100 shown in Figures 1 to 8. The leak detection sensor 500 used was the LLC210D3 series manufactured by SST Sensing. Water was used as the liquid.

The leak detection device 100 was placed on a smooth, flat surface, and the height at which water was detected was measured. This was performed five times, and the average height was 1.76 mm.

(Example 2)
Similarly, a liquid detection experiment was conducted using the leak detection device 100 shown in Figures 1 to 8. The leak detection sensor 500 used was the LLC210D3 series manufactured by SST Sensing. Oil was used as the liquid.

The leak detection device 100 was placed on a smooth, flat surface, and the height at which oil was detected was measured. This was performed five times, and the average height was 1.82 mm.

(Example 3)
Next, we conducted an experiment on heat resistance. The specifications of the leak detection device 100 were the same as those used in Example 1 or 2. We checked whether the leak detection device 100 would operate when the cooking oil was heated to 120 degrees Celsius.
The leak detection device 100 was immersed in 120-degree Celsius cooking oil for 30 minutes. As a result, the leak detection device 100 activated. Furthermore, the leak detection device 100 was immersed in 120-degree Celsius cooking oil for another 30 minutes, for a total of 1 hour. As a result, the leak detection device 100 activated.

(Example 4)
Next, we experimented with the heat resistance of the leak detection device 100 itself. The specifications of the leak detection device 100 were the same as those used in Example 1 or 2. We checked whether the leak detection device 100 would operate when it was heated to 123 degrees Celsius using a heat gun. As a result, the leak detection device 100 operated.

(Example 5)
Next, we experimented with the heat resistance of the leak detection device 100 itself. The specifications of the leak detection device 100 were the same as those used in Example 1 or 2. The leak detection device 100 itself was immersed in 98-degree Celsius hot water in an electric water heater for 24 hours to check if the leak detection device 100 would operate. As a result, the leak detection device 100 operated.

(Example 6)
Next, we conducted an experiment on the heat resistance of the magnet 350 used in the leak detection device 100. The magnet 350 used was a heat-resistant neodymium magnet manufactured by Misumi, model number NHXCCH. The temperature before heating was 29.3 degrees Celsius, and the tesla meter was placed at the position where the magnetic force was 10.0 mT. The experiment was started and the magnet was heated up to 120 degrees Celsius, but there was no change in the position where the magnetic force was 10.0 mT.

(Example 7)
Next, we checked whether the leak detection device 100 would operate on a flat surface made of a mirrored material. On a flat surface made of a highly reflective mirrored material, operation was confirmed even when the liquid was oil. However, it could not detect water.
Because this uses a reflective leak detection sensor 500, when the refractive index of air is 1.0, i.e., when there is no leak, the infrared radiation emitted from the infrared phototransistor is received by the infrared receiving module in a specified amount via the prism lens.
On the other hand, when the liquid is water, the refractive index is 1.3, so the infrared radiation emitted from the infrared phototransistor does not return a specified amount of infrared radiation to the infrared receiving module via the prism lens, and therefore can be detected. However, it has been found that on a flat surface of a mirror material, a specified amount of infrared radiation emitted from the infrared phototransistor may return to the infrared receiving module via the prism lens.
On the other hand, when the liquid is oil, the refractive index is around 1.4 or 1.5, so it was found that even on a flat surface of a mirror material, the infrared radiation emitted from the infrared phototransistor does not return a specified amount of infrared radiation to the infrared receiving module via the prism lens.

From the above, it was found that when leak detection is performed using the leak detection device 100 according to this embodiment, reliable detection is achieved when the immersion height from the bottom surface of the leak detection device 100 is 1.87 mm. Considering safety, it was found that detection is possible at a height of 2.00 mm. Furthermore, it was found that the device operates without problems up to 120 degrees Celsius. In addition, it was found that the device operates reliably on a mirror-finished surface when the liquid is oil.

(Other examples)
Figure 9 is a schematic assembly cross-sectional view showing another example of the leak detection device 100 shown in Figures 1 to 8, and Figure 10 is a partially enlarged schematic view of another example of the leak detection device 100 shown in Figure 9. The differences from the leak detection device 100 shown in Figures 1 to 8 will be explained below.

In other examples, as shown in Figures 9 and 10, a hole forming portion 217 is formed at the lower part of the through hole 210 to form a through hole portion 213a having a diameter smaller than the inner diameter of the through hole 210.
The hole-forming portion 217 is formed to protrude inward from the through-hole 210.
Furthermore, the diameter of the through-hole portion 213a formed by the hole-forming portion 217 is formed to be slightly larger than the conical shape 520, and the size of the gap is preferably 0.2 mm or more and 1.5 mm or less. More preferably, the size of the gap is 0.5 mm or more and 0.8 mm or less.
Furthermore, the size of the gap may be changed to any value depending on the viscosity and temperature of the liquid being detected.
Furthermore, the through-hole portion 213a and the hole-forming portion 217, which form gaps, are preferably made of a surface material that absorbs light or a material that transmits light, or a light-absorbing material may be applied to them.

As a result, as shown in the enlarged schematic diagram of section B in Figure 10, the liquid can be allowed to flow in the direction of arrow FL. Consequently, even when the outflow rate of liquid is small, the liquid can be guided to the conical shape 520 containing the detection unit by capillary action, enabling reliable detection.

(More examples)
Figure 11 is a schematic assembly cross-sectional view showing yet another example of the leak detection device 100 shown in Figures 1 to 8, and Figure 12 is a partially enlarged schematic view of another example of the leak detection device 100 of Figure 11. The differences from the leak detection device 100 shown in Figures 1 to 8 will be explained below.

In another example, as shown in Figures 11 and 12, a hole forming portion 215 is formed below the through hole 210 to form a through hole portion 213a having a diameter smaller than the inner diameter of the through hole 210.
The hole-forming portion 215 is formed to protrude inward from the through-hole 210 and is provided at the same angle as the inclination angle of the conical shape 520.
Furthermore, the diameter of the through-hole portion 213a formed by the hole-forming portion 215 is formed to be slightly larger than the conical shape 520, and the size of the gap is preferably 0.2 mm or more and 1.5 mm or less. More preferably, the size of the gap is 0.5 mm or more and 0.8 mm or less.
Furthermore, the size of the gap may be changed to any value depending on the viscosity and temperature of the liquid being detected.
Furthermore, the through-hole portion 213a and the hole-forming portion 215, which form gaps, are preferably made of a surface material that absorbs light or a material that transmits light, or a light-absorbing material may be applied to them.

As a result, as shown in the enlarged schematic diagram of section C in Figure 12, the liquid can be allowed to flow in the direction of arrow FL. Consequently, even when the outflow rate of liquid is small, the liquid can be guided to the conical shape 520 containing the detection unit by capillary action, enabling reliable detection.

(More examples)
Figure 13 is a schematic assembled perspective view showing yet another example of the leak detection device 100 shown in Figures 1 to 8, and Figure 14 is a schematic assembled cross-sectional view showing yet another example of the leak detection device 100 shown in Figures 1 to 8. Figure 15 is a partially enlarged schematic view of another example of the leak detection device 100 shown in Figure 14. The differences from the leak detection device 100 shown in Figures 1 to 8 will be explained below.

(Liquid guide section 400)
In other examples, as shown in Figures 13, 14, and 15, a liquid guide portion 400 made of a separate material is used as the gap-forming portion. The liquid guide portion 400 is preferably made of a heat-resistant resin, particularly a resin with a heat resistance of 120 degrees Celsius or higher. For example, it is preferably made of PP (polypropylene), PPS (polyphenylene sulfide), flame-retardant ABS resin, or aluminum.
The liquid guide portion 400 consists of a cylindrical portion 410 and a conical portion 420, with a notch 415 formed in the cylindrical portion 410. The notch 415 is preferably 2 mm wide. The notch 415, like the air through-hole 255, is for creating an escape route for air. Therefore, the width can be any width as long as it is large enough for air to escape. Furthermore, a hole 425 is formed at the tip of the conical portion 420.

The hole 425 has a diameter smaller than the inner diameter of the through hole 210. In this example, the angle of the conical portion 420 is set to the same angle as the inclination angle of the conical shape 520.
Furthermore, the diameter of the hole 425 is formed to be slightly larger than that of the conical shape 520, and the size of the gap is preferably 0.2 mm or more and 1.5 mm or less. More preferably, the size of the gap is 0.5 mm or more and 0.8 mm or less.
Furthermore, the size of the gap may be changed to any value depending on the viscosity and temperature of the liquid being detected.

Furthermore, at least the pores 425 and the conical portion 420, which form the gaps, are preferably made of a light-absorbing surface material or a light-transmitting material, or a light-absorbing material may be applied to them. Moreover, the entire liquid guide portion 400 may be made of a light-absorbing surface material or a light-transmitting material, or a light-absorbing material may be applied to it.

Next, as shown in Figure 14, the leak detection sensor 500 is inserted and fixed from the top side of the fixed case 200, and the liquid guide portion 400 is inserted from below the fixed case 200.
Alternatively, the liquid guide section 400 may be attached to the leak detection sensor 500 before inserting it into the fixing case 200.

As a result, as shown in the enlarged schematic diagram of section D in Figure 15, the liquid can be allowed to flow in the direction of arrow FL. Consequently, even when the outflow rate of liquid is small, the liquid can be guided to the conical shape 520 containing the detection unit by capillary action, enabling reliable detection.

(Another example of the liquid guide section 400)
Figure 16 is a schematic cross-sectional view showing another example of the liquid guide section 400.
In Figure 16, the liquid guide portion 400 has a cylindrical portion 410 instead of a conical portion 420, with an inclined surface 421 provided on its inner surface so that it is mortar-shaped. The liquid guide portion 400 is preferably made of a heat-resistant resin, particularly a resin that can withstand temperatures of 120 degrees Celsius or higher. For example, it is preferably made of PP (polypropylene), PPS (polyphenylene sulfide), flame-retardant ABS resin, or aluminum.

Furthermore, at least the holes 425 and inclined surfaces 421, which form the gaps, are preferably made of a light-absorbing surface material or a light-transmitting material, or a light-absorbing material may be applied. Moreover, the entire liquid guide portion 400 may be made of a light-absorbing surface material or a light-transmitting material, or a light-absorbing material may be applied.

Thus, even when the liquid guide section 400 is formed, the liquid can be allowed to flow in the direction of arrow FL, as shown in the enlarged schematic diagram of section D in Figure 15. As a result, even when the amount of liquid outflow is small, the liquid can be guided to the conical shape 520 containing the detection section by capillary action, enabling reliable detection.

(Other examples of leg portion 220)
The following describes other examples that can be applied to the leak detection device 100 explained in Figures 1 to 16.
Figure 17 is a schematic side view showing another example of the legs 220 of the fixed case 200 of the leak detection device 100, Figure 18 is a schematic bottom view showing another example of the legs 220 of the fixed case 200 of the leak detection device 100, and Figure 19 is a schematic cross-sectional view showing another example of the legs 220 of the fixed case 200 of the leak detection device 100.

As shown in Figures 17 to 19, the legs 220 of the fixed case 200 may have a tapered shape. In the example shown in Figures 17 to 19, the legs 220 have a tapered shape that slopes downward toward the lower end of the through hole 210. In this case, the magnet 350 is provided protruding from the tapered legs 220.
As a result, liquid can be guided from the entire circumference of the leg portion 220 to the through hole 210.

In this embodiment, the cylindrical shape 510 of the leak detection sensor 500 corresponds to the "cylindrical shape of the leak detection sensor," the conical shape 520 of the leak detection sensor 500 corresponds to the "conical shape of the leak detection sensor," the threaded portion 580 of the leak detection sensor 500 corresponds to the "threaded portion of the leak detection sensor," the leak detection sensor 500 corresponds to the "leak detection sensor," the fixing case 200 corresponds to the "fixing case," the through hole 210 corresponds to the "through hole," and the threaded portion 280 corresponds to the "fitting portion." The following are equivalent to the following: the air through-hole 255 corresponds to the "air through-hole," the leg portion 220 corresponds to the "leg portion," the magnet 350 corresponds to the "magnet," the gap-forming portion 213, the hole-forming portions 215 and 217, and the liquid guide portion 400 correspond to the "gap-forming portion," the D-cut surface 240 corresponds to the "mounting surface," the inclined surface 421 and the hole-forming portion 215 correspond to the "truncated inverted cone portion," and the hole 425, the hole-forming portion 217, and the through-hole portion 213a correspond to the "through-hole portion with a diameter smaller than the diameter of the through-hole."

While the above describes a preferred embodiment of the present invention, the invention is not limited thereto. It will be understood that various other embodiments can be made without departing from the spirit and scope of the invention. Furthermore, although the operation and effects of the configuration of the present invention are described in this embodiment, these operations and effects are examples only and do not limit the invention.

100: Leak detection device 200: Fixed case 210: Through hole 213: Gap forming part 213a: Through hole part 215: Hole forming part 217: Hole forming part 220: Leg part 240: D-cut surface 255: Air through hole 260: Hole 265: Screw hole 280: Screw part 350: Magnet 400: Liquid guide part 410: Cylindrical part 415: Notch part 420: Conical part 421: Inclined surface 425: Hole 500: Leak detection sensor 510: Cylindrical shape 520: Conical shape 550: Electric wire 580: Screw part FL: Arrow

Claims (7)

A fixing case for fixing the detection portion of a prism lens of a leak detection sensor, which includes a cylindrical end with a cone shape formed thereon, a screw portion formed in the cylindrical shape, a light-emitting element, a light-receiving element, and a prism lens, with the detection portion of the prism lens facing downwards,
It consists of a cylindrical shape having a predetermined height,
The through hole in the shaft of the cylinder,
The upper part of the through hole is a fitting portion that fits with the screw portion,
An air through-hole provided from the side of the cylinder to the aforementioned through-hole,
Legs provided on the back,
The magnet provided on the leg portion,
A fixing case including a gap-forming portion at the lower part of the through-hole, which forms a predetermined gap between it and the conical detection portion. The cylindrical shape has a mounting surface formed therein.
The mounting surface further includes a magnet,
The fixed case according to claim 1, wherein the legs consist of a pair of fan-shaped parts. The fixing case according to claim 1, wherein the gap-forming portion is made of a separate member and has a cylindrical portion that fits inside the through-hole, and a truncated inverted cone portion on the inner surface of one end of the cylindrical portion. The fixing case according to claim 1, wherein the gap-forming portion is formed on the lower side of the through hole and has a truncated inverted cone portion on the inner surface of the lower side of the through hole. The fixing case according to claim 1, wherein the gap-forming portion is formed on the lower side of the through-hole, and has a through-hole portion with a diameter smaller than the diameter of the through-hole on the inner surface of the lower side of the through-hole. The fixing case according to any one of claims 3 to 5, wherein the gap-forming portion is made of a surface material that absorbs light or a material that transmits light. A leak detection sensor comprising a cylindrical end with a conical shape and a threaded portion formed in the cylindrical shape, a light-emitting element, a light-receiving element, and a prism lens,
It has a cylindrical shape with a predetermined height and a mounting surface formed therein.
The through hole in the shaft of the cylinder,
The upper part of the through hole is a fitting portion that fits with the screw portion,
An air through-hole provided from the side of the cylinder to the aforementioned through-hole,
Legs provided on the back,
The magnet provided on the leg portion,
The fixing case includes a gap-forming portion that forms a predetermined gap between the through-hole and the conical shape at the lower part of the through-hole,
A leak detection device comprising the detection portion of the prism lens of the leak detection sensor facing downwards, and the screw portion of the leak detection sensor fixed to the fitting portion of the fixing case.