JP7575963B2 - Liquid Level Detection Device - Google Patents

Description

The present invention relates to a liquid level detection device capable of detecting the liquid level of a liquid to be detected stored in a container.

Conventionally, there are liquid level detection devices capable of detecting the liquid level of a detectable liquid, such as those arranged to detect the liquid level of drain water (detectable liquid) stored in a drain tank (container) installed in equipment such as dehumidifiers used in homes and offices, and refrigerated showcases for displaying products installed in stores such as supermarkets.

An example of a float-type liquid level detection device applied to a refrigerated showcase is one in which a float switch is installed on a float switch mounting cover attached to the top of a drain tank, and when the water level in the drain tank reaches full capacity, the float rises and switches the connection state of the electrical contacts, outputting a detection signal (see, for example, Patent Document 1).

Another example of an ultrasonic liquid level detection device applied to a refrigerated showcase is one in which an ultrasonic sensor is installed above a drain tank, and the water level is detected by measuring the time it takes for ultrasonic waves emitted toward the water surface to be reflected back and received by the water surface, and calculating the distance between the ultrasonic sensor and the water surface (see, for example, Patent Document 2).

JP-A-9-68380 (page 4, see FIG. 6) JP 2008-20111 A (see page 1, FIG. 1)

However, the float-type liquid level detection device described in Patent Document 1 has a float that floats on the liquid surface in the drain tank, so when applied to a drain tank with a short vertical dimension, the float's range of motion is small, resulting in poor detection sensitivity and making it difficult to detect a full-water state. In addition, the ultrasonic liquid level detection device described in Patent Document 2 has high implementation costs because it uses precision equipment in the transmitter and receiver that emit ultrasonic pulse signals toward the liquid surface. In addition, even the slightest deviation in the positional relationship between the installation position of the ultrasonic sensor and the drain tank causes the opening edge of the drain tank to enter the measurement range of the ultrasonic sensor, making it difficult to accurately detect the liquid level, making it difficult to handle.

In addition to the above, there is an electrode-type liquid level detector that has no detection range limitations and is inexpensive. In this type of device, multiple detectors each having electrodes connected to a circuit are inserted into a container that holds the liquid to be detected, and the liquid to be detected comes into contact with the detection electrode of one of the detectors and a common electrode that forms an earth circuit with the detector. The liquid level is detected by detecting the current that flows through the detector. However, the detector must be handled carefully because the detector is rod-shaped and there is a risk that it may come into contact with the container when it is inserted into or pulled out of the container opening from above, causing it to bend or break.

The present invention was developed to address these problems, and aims to provide a liquid level detection device that is easy to use and capable of detecting the liquid level accurately.

In order to solve the above problems, the liquid level detection device of the present invention comprises:
A liquid level detection device capable of detecting a liquid level by contacting an electrode of a detection body inserted into a drain tank through an opening formed in an upper portion of the drain tank with the drain water,
The detection body is flexible and suspended from a predetermined member separate from the drain tank so as to hang down vertically downward,
an electrode arrangement portion in which the electrode is arranged and communicates with the inside of the drain tank is provided at the opening , the electrode arrangement portion being formed in a box shape having a bottom wall portion and a peripheral wall portion standing on an upper peripheral edge of the bottom wall portion and opening upward from the bottom wall portion ;
The drain tank is characterized in that it can be moved horizontally together with the electrode placement portion and pulled out.
According to this feature, since the detection body has flexibility, even if the detection body comes into contact with the container, the impact is mitigated and the detection body hangs down within the opening, making it easy to handle and enabling accurate detection of the liquid level.

The detection body is characterized in that it is a chain formed by joining a plurality of electrically conductive members to be joined into a linear shape.
According to this feature, when the detection body is lowered, the joined members come into contact with each other due to their own weight, so that the conductivity of the detection body is maintained.

The plurality of joined members are spherical, and the plurality of joined members are joined by linear joining members.
According to this feature, since the surface of the joined member is spherical, it is slippery when it comes into contact with a container or the like, and is therefore less likely to get caught on the opening of the container.

The detection body is characterized by including a first detection body having a first electrode, and a second detection body having a second electrode arranged at a position spaced a predetermined horizontal distance from the first detection body.
According to this feature, the two electrodes are suspended by separate detection bodies spaced apart from each other, so that the electrodes are unlikely to come into contact with each other.

The first detection body and the second detection body are suspended by a predetermined member separate from the container,
The container is characterized in that it can be drawn out by moving the first detection body and the second detection body from an installation position where they are inserted into the opening in a specific horizontal direction intersecting the predetermined horizontal direction.
According to this feature, the detectable liquid stored in the container can be drained by pulling the container out of its installation position without removing the detection body including the electrode from the designated member, and the two electrodes are prevented from coming into contact or becoming entangled when the container is pulled out of its installation position.

an electrode arrangement section in which the electrode is arranged is provided at a position inside the container corresponding to the opening, the electrode arrangement section being formed in a box shape having a bottom wall section and a peripheral wall section standing on an upper peripheral edge of the bottom wall section and opening upward;
When the liquid level of the liquid to be detected reaches a predetermined liquid level, the liquid to be detected is allowed to enter the electrode arrangement portion.
According to this feature, the liquid to be detected will not enter the electrode placement portion until its level reaches a predetermined level, and the liquid level will not be detected until the liquid to be detected in the electrode placement portion reaches a predetermined level. This prevents the liquid level from being detected when the predetermined level has not been reached due to the liquid to be detected rippling due to vibration, and makes it possible to detect the predetermined liquid level with the detection body inserted deeply into the electrode placement portion.

The inner surface of the peripheral wall of the electrode placement portion is characterized in that it slopes outwardly as it goes upward.
According to this feature, when the detection body is inserted into the opening or pulled out from the opening, it is guided by the inclined surface formed on the inner surface of the peripheral wall portion, and is less likely to get caught on the periphery of the opening.

The container is characterized in that a mounting member on which the electrode can be placed is provided between the opening inside the container and a bottom wall of the container.
According to this feature, by placing the electrodes on the placement member, the electrodes can be easily positioned at a desired liquid level regardless of the length of the detection body.

1 is a perspective view showing a refrigerated showcase to which a liquid level detection device of the present invention is applied; FIG. 2 is a vertical cross-sectional view showing the inside of the refrigerated showcase of FIG. 1. FIG. 3 is an enlarged longitudinal sectional view of a main portion of FIG. 2 . This is a cross-sectional view taken along line AA in FIG. 1A is a plan view showing the drain tank, FIG. 1B is a cross-sectional view taken along line B-B of FIG. 1A, FIG. 1C is a cross-sectional view taken along line C-C of FIG. 1A, and FIG. 1D is a cross-sectional view taken along line D-D of FIG. 5A to 5C are enlarged cross-sectional views of essential parts showing a state in which drain water is stored in a drain tank and the liquid level is detected. 5A to 5D are enlarged cross-sectional views of the essential parts showing the manner in which the drain tank is installed at the installation position. 5A to 5D are enlarged cross-sectional views showing the state when the drain tank is pulled out from the installed position. 1A is a cross-sectional view showing a first modified example of the detection body, and FIG. 1B is a cross-sectional view showing a second modified example of the detection body.

The following describes an embodiment of the liquid level detection device according to the present invention.

A refrigerated showcase to which a liquid level detection device according to an embodiment of the present invention is applied will be described with reference to Figs. 1 to 8. In the following description, the lower left side of Fig. 1 is the front side (front side) of the refrigerated showcase, and the upper right side of Fig. 2 is the back side (rear side) of the refrigerated showcase, and the description will be based on the up, down, left and right directions when the refrigerated showcase is viewed from the front side.

The refrigerated showcase 1 shown in FIG. 1 is installed in sales outlets such as shops, supermarkets, and convenience stores that handle vegetables, fruits, and other fresh foods, as well as other foodstuffs (hereinafter referred to as "goods"), and is installed to display the goods sold by the store when a customer makes a purchase. In particular, the refrigerated showcase 1 in this embodiment is a refrigerated showcase equipped with a flat open showcase 2 that opens upward, and is used in places such as eat-in corners and specialty stores where face-to-face sales are conducted, with customers positioned at the front and store clerks positioned at the back, with the refrigerated showcase 1 in between.

As shown in Figs. 1 and 2, the refrigerated showcase 1 is mainly composed of a cold storage compartment 4 in which refrigerated display items (not shown) are cooled and stored, and a base 5 provided below the flat open showcase 2. The base 5 is equipped with a refrigerator unit 43, which is composed of a compressor, a condenser, a blower, etc. (not shown) connected by refrigerant piping, a drain water evaporation device 9, and an electrode type level switch 10. The refrigerator unit 43 is connected to an evaporator 41 and a blower 42 (see Fig. 2) arranged in the cold air circulation path 26, and a refrigeration cycle is performed by the refrigerator unit 43, the evaporator 41, and the blower 42, so that the cold storage compartment 4 is cooled by cold air blown from an outlet 7 provided at the top of the cold air circulation path 26 toward an inlet 8.

The cold storage compartment 4 comprises a case body 21 formed in a generally inverted L-shape in cross section, and panel units 27, 27 disposed on both the left and right ends of the case body 21. In addition, the cold storage compartment 4 is configured in a box shape with an opening from the front side to the top side, with a translucent front panel 28 made of acrylic resin erected at the front end of the lower part of the case body 21 across the left and right ends.

As shown in FIG. 2, the case body 21 is composed of an outer case 22 with a heat-insulating structure that is generally inverted L-shaped in cross section, and an inner case 23 inside that that is also generally inverted L-shaped in cross section, and items to be displayed in a refrigerated state can be displayed on the top surface 29 of the bottom 23b of the inner case 23.

The refrigerated showcase 1 periodically performs a defrosting operation to melt the frost near the evaporator 41 caused by the temperature difference with the outside air. During this defrosting operation, the frost melts and generates drain water. The drain water generated by this defrosting operation is stored in the drain water evaporator 9 and evaporated. The drain water evaporator 9 includes a drain pan (not shown) that stores the drain water discharged from the evaporator 41, and an evaporation member (not shown) made of a nonwoven fabric that evaporates the impregnated drain water. In addition, an overflow pipe 90 (see FIG. 3) is extended from the drain water evaporator 9 toward the drain tank 6 arranged on the underside of the bottom plate 5b of the base 5, and when a large amount of drain water is generated during defrosting, the drain water stored in the drain pan passes through the overflow pipe 90 and is discharged into the drain tank 6.

The drain tank 6 is provided so as to be slidable in the front-rear direction relative to the base 5 via a pair of left and right guide rails 5a, 5a (see FIG. 1) facing the front-rear direction and attached to the left side of the underside of the bottom plate 5b of the base 5, and can be removed from the refrigerated showcase 1 by sliding it from the installation position (position shown in FIGS. 2 to 4) on the underside of the bottom plate 5b to the front side (see FIG. 1). In addition, in the installation position, the rearward sliding movement of the drain tank 6 is restricted by a restricting portion (not shown) provided on the guide rails 5a, 5a, so that the drain tank 6 can be easily positioned in the installation position by pushing it rearward from the front side of the refrigerated showcase 1 until its sliding movement is restricted.

2, 3, and 4, the electrode-type level switch 10 as a liquid level detection device for detecting the liquid level of the drain tank 6 has a support member 11, a ball chain 12 as a first detection body and a ball chain 13 as a second detection body suspended by the support member 11. The support member 11 houses a circuit board (not shown) on which a detection circuit is provided, and the ball chains 12, 13 and a cable 10a are electrically connected to the circuit board. The ball chain 12 functions as an earth electrode, and the ball chain 13 functions as a detection electrode. When an AC voltage is applied to these electrodes and the conductive liquid to be detected (drain water D in this embodiment) comes into contact with both the ball chains 12, 13, a current flows through the drain water D between the ball chains 12, 13, the detection circuit becomes a closed circuit, and it is detected that the liquid level of the drain tank 6 has reached a predetermined liquid level (full liquid level in this embodiment). Here, the ball chains 12 and 13 are the detection bodies and electrodes of the present invention and are entirely made of conductive metal materials.

A signal is output from the circuit board through cable 10a to a notification means (not shown, for example, a display device or lamp), which notifies the user that the liquid level in the drain tank 6 has reached a predetermined level, and prompts the user to drain the drain water. In this embodiment, the full liquid level can be detected, but it is also possible to detect a liquid level other than the full liquid level, or to detect multiple liquid levels. In addition, a circuit board having a detection circuit is housed in the support member 11, but the detection circuit may be located in a location other than the support member 11.

The support member 11 is attached to a mounting bracket 5c, which is a predetermined member arranged at a predetermined position within the base 5, by a screw member (not shown). The upper end of the ball chain 12 is suspended from the left side of the front part 11F of the support member 11, and the upper end of the ball chain 13 is suspended from the right side of the front part 11F. In this way, the ball chain 13 is suspended at a position at least a predetermined distance (e.g., at least about 5 cm) to the right from the ball chain 12 (see Figure 4). A cable 10a including a power line and a signal line for supplying power to the circuit board extends from the rear part 11B.

In addition, below the mounting bracket 5c on the bottom plate 5b of the base 5, a through hole 5d is formed, through which the ball chains 12, 13 can be inserted. The lower parts of the ball chains 12, 13 inserted through the through hole 5d are inserted into the drain tank 6 at the installation position from approximately the center of openings 66a, 66b (described later) and are arranged in the first electrode arrangement section 61 and the second electrode arrangement section 62. When the drain tank 6 is in the installation position, the openings 66a, 66b are positioned vertically below the through hole 5d in the bottom plate 5b.

The ball chains 12 and 13 have a plurality of hollow spherical joined members 12a and 13a made of metal material and a rod-shaped joining member 12b and 13b made of metal material, and are formed into a chain shape by joining the plurality of joined members 12a and 13a with the joining members 12b and 13b. The longitudinal dimensions of the ball chains 12 and 13 are approximately the same, and the lower ends are located slightly above the upper surfaces of the bottom walls 61a and 62a described later. In detail, the ball chains 12 and 13 have one end of each joining member 12b and 13b that can be bent relative to the hollow joined members 12a and 13a and are engaged with the joined members 12a and 13a in an expandable and contractible manner, so that when an external force is applied, the joints between the joined members 12a and 13a and the joining members 12b and 13b are bent, and can be deformed in a non-linear shape. In other words, they have flexibility. On the other hand, when no external force is being applied, such as when it is in contact with other components, it will hang down vertically under its own weight and become linear.

The ball chains 12, 13 are suspended vertically downward from the support member 11 and are positioned at a detection position where their lower portions are inserted into the through-hole 5d. In this state, the ends of the joining members 12b, 13b of the ball chains 12, 13 are in contact with the joined members 12a, 13a due to the weight of each joined member 12a, 13a, and the entire ball chains are electrically connected. In addition, the multiple joined members 12a, 13a and the joining members 12b, 13b that make up the ball chains 12, 13 are all made of metal, so the entire ball chains 12, 13 function as electrodes.

Next, the drain tank 6 will be described with reference to Figures 5(a) to (d). As shown in Figure 5(a), the drain tank 6 is formed by blow molding a resin material into a thin box shape that is roughly rectangular in plan view, and has a storage space A inside that can store drain water. As shown in Figures 5(a) and (d), a drain water inlet 6c is formed on the left side of the upper plate 6a, through which drain water D discharged from the overflow pipe 90 can be introduced into the storage space A.

A drain water outlet 6f is formed in the front left part of the upper plate 6a to discharge the drain water stored in the storage space A. In addition, a rectangular through hole 6e that penetrates from the upper plate 6a to the lower plate 6b is formed along the left side edge to the left of the drain water inlet 6c, and by gripping the handle 6g formed by the through hole 6e, it is easy to carry the drain tank 6 and to drain the drain water from the drain water outlet 6f.

As shown in Figures 5(a) and (c), multiple recesses 6d are formed inwardly at corresponding positions on the upper plate 6a and the lower plate 6b of the drain tank 6. The recesses 6d are formed in a generally circular shape in a plan view, and the recesses 6d formed on the upper plate 6a side and the recesses 6d formed on the lower plate 6b side are joined together, so that the upper plate 6a and the lower plate 6b of the drain tank 6 are integrated and less likely to bend. The drain tank 6 is formed thin so that the vertical dimension is shorter than the front-to-rear and left-to-right dimensions. Therefore, the drain tank 6 can be stored in the narrow space between the bottom plate 5b and the floor surface.

As shown in FIG. 5(b), stepped recesses 6h, 6h that are recessed toward the upper plate 6a are formed along the left and right sides at the left and right ends of the lower plate 6b of the drain tank 6. When the stepped recesses 6h, 6h are placed on the guide rails 5a, 5a attached to the underside of the bottom plate 5b of the base 5, the underside of the guide rails 5a and the lower plate 6b of the drain tank 6 become approximately flush with each other.

As shown in Figs. 5(a), (b), and (d), a first electrode arrangement section 61 and a second electrode arrangement section 62 that are recessed downward are provided between the drain water inlet 6c and the drain water outlet 6f on the upper plate 6a of the drain tank 6. Since the first electrode arrangement section 61 and the second electrode arrangement section 62 have substantially the same configuration, the following description will be omitted for the second electrode arrangement section 62, and the first electrode arrangement section 61 will be described in detail.

The first electrode placement section 61 is formed in a box shape that opens upward, and extends long in the direction in which the drain tank 6 is inserted into and removed from the base 5 (front-rear direction). As shown in Figs. 5(b) and (d), the first electrode placement section 61 is formed of a bottom wall section 61a that is approximately parallel to the lower plate 6b, side wall sections 61d, 61d erected on both left and right edges of the bottom wall section 61a, and front-rear wall sections 61f, 61f erected on both front and rear edges of the bottom wall section 61a, and is open upward by an opening 66a formed in the upper plate 6a.

The bottom wall portion 61a is located slightly below the midpoint between the lower plate 6b and the upper plate 6a of the drain tank 6, the upper edges of the side wall portions 61d, 61d are connected to the upper plate 6a, and the upper edges of the front and rear wall portions 61f, 61f are connected to the upper plate 6a. In other words, the first electrode arrangement portion 61 is a recess formed in the upper plate 6a when the drain tank 6 is molded.

The front and rear wall portions 61f, 61f have inclined wall portions 61b, 61b that incline upward in the front-rear direction (outward) from both front and rear ends of the bottom wall portion 61a, slits 61c, 61c formed at the front and rear ends of the inclined wall portions 61b, 61b, and vertical wall portions 61e, 61e that stand upward from the front and rear ends of the slits 61c, 61c and connect to the upper plate 6a. The side wall portions 61d, 61d are inclined outward (left and right) toward the top. The slits 61c, 61c are formed in a roughly rectangular shape in a plan view, and are formed to a size that allows water to pass through but does not allow the joined member 12a of the ball chain 12 to pass through.

In addition, the first electrode placement section 61 and the second electrode placement section 62 are arranged adjacent to each other on the left and right in correspondence with the openings 66a, 66b formed separately, and a partition section 63 having a generally inverted V shape in vertical cross section is provided between the first electrode placement section 61 and the second electrode placement section 62, which consists of the side walls 61d, 61d of the first electrode placement section 61 and the second electrode placement section 62 and the upper plate 6a between the side walls 61d, 61d. Therefore, even when the ball chains 12, 13 swing due to vibration, the lower ends of the ball chains 12, 13 are arranged in separate spaces, preventing contact between the electrodes.

In addition, slits 61c, 61c are formed at the upper ends of the inclined wall portions 61b, 61b, i.e., above the bottom wall portion 61a, so that the internal space of the first electrode placement portion 61 is connected to the storage space A, and when the drain water D is stored in the storage space A at or above a predetermined liquid level (the liquid level corresponding to the slit 61c), the drain water D passes through the slit 61c and enters the first electrode placement portion 61.

In this embodiment, the first electrode arrangement portion 61 and the second electrode arrangement portion 62 are formed integrally with the upper plate 6a by forming the portions corresponding to the openings 66a and 66b in the upper plate 6a in a concave shape, but they may be configured as boxes formed separately from the upper plate 6a. For example, the first electrode arrangement portion 61 and the second electrode arrangement portion 62 formed in a box shape opening upward from the bottom wall portion and the peripheral wall portion erected on the upper peripheral edge of the bottom wall portion may be fixed to the lower plate 6b at a position below the openings 66a and 66b so that a gap is formed between the upper end of the peripheral wall portion and the upper plate 6a, and the drain water D may enter through the gap when the liquid level in the storage space A reaches a predetermined liquid level. In addition, although the first electrode arrangement portion 61 and the second electrode arrangement portion 62 are formed in a rectangular shape in a plan view extending in the movement direction of the drain tank 6, the shape can be arbitrarily changed, such as a substantially circular shape in a plan view.

Next, using Figures 6(a) to (c), we will explain how drain water is stored in the drain tank 6 and how the electrode-type level switch 10 detects a predetermined liquid level (full liquid level).

6(a) shows a state in which a small amount of drain water D is stored in the storage space A of the drain tank 6. At this time, the liquid level of the drain water D in the storage space A is below the slit 61c and has not yet reached a predetermined liquid level (the liquid level corresponding to the slit 61c), so that the drain water D does not enter the first electrode arrangement portion 61 or the second electrode arrangement portion 62. Furthermore, even if the drain water D ripples due to vibrations caused by external forces such as when the refrigerated showcase 1 is operating or when a person or object comes into contact with the refrigerated showcase 1, or when a small amount of drain water D enters the first electrode arrangement section 61 or the second electrode arrangement section 62 through the slit 61c due to drain water D flowing in from the overflow pipe 90, the drain water D in the first electrode arrangement section 61 and the drain water D in the second electrode arrangement section 62 are not connected via the drain water D in the storage space A, so no current flows between the ball chain 12 and the ball chain 13 and the specified liquid level is not detected.

Figure 6 (b) shows the state in which the drain water D enters the first electrode arrangement part 61 and the second electrode arrangement part 62 from the slits 61c, 61c. At this time, the liquid level of the drain water D in the storage space A reaches a predetermined liquid level (full liquid level) corresponding to the slit 61c, but the liquid level of the drain water D stored in the first electrode arrangement part 61 and the second electrode arrangement part 62 does not reach the predetermined liquid level. In other words, the drain water D in the first electrode arrangement part 61 and the drain water D in the second electrode arrangement part 62 are not connected via the drain water D in the storage space A, so in Figure 6 (b), no current flows between the ball chain 12 and the ball chain 13. In this way, it is preferable that the slit 61c is formed at a position where the drain water D enters the inside of the first electrode arrangement part 61 and the second electrode arrangement part 62 when the storage space A reaches the full liquid level.

6(c) shows a state in which the liquid level of the drain water D that has entered the first electrode arrangement portion 61 and the second electrode arrangement portion 62 has risen to a predetermined liquid level. At this time, the liquid level in the storage space A of the drain water D and the liquid level of the drain water D in the first electrode arrangement portion 61 and the second electrode arrangement portion 62 become approximately the same at a predetermined liquid level above the slit 61c, and the drain water D stored in the first electrode arrangement portion 61 and the drain water D stored in the second electrode arrangement portion 62 are connected via the drain water D stored in the storage space A, and the reaching of the predetermined liquid level is detected by the current flowing between the ball chain 12 and the ball chain 13, and it is notified that the drain water D is full. In addition, ball chain 12 and ball chain 13 have a higher density than drain water D, so they hang down vertically even when drain water D is stored in first electrode arrangement section 61 and second electrode arrangement section 62.

Next, the state of the ball chain 12 when the empty drain tank 6 is installed in the installation position will be described using Figures 7(a) to (d). Note that since the ball chains 12 and 13 have substantially the same deformation state, only the state of the ball chain 12 will be described.

When installing an empty drain tank 6 in the installation position, as shown in FIG. 7(a), the drain tank 6 is positioned so that the lower surface of the stepped recesses 6h, 6h (see FIG. 4) formed in the lower plate 6b of the drain tank 6 is positioned on the upper surface of the guide rails 5a, 5a, and the rear end 6B of the drain tank 6 is inserted into the lower part of the base 5. The lower part of the ball chain 12 is suspended so as to be positioned lower than the through hole 5d of the bottom plate 5b, so when the rear end 6B of the drain tank 6 is inserted, it comes into contact with the lower part of the ball chain 12, but since the ball chain 12 is flexible, it bends (deforms) in the direction of movement of the drain tank 6 (towards the back side).

As shown in FIG. 7(b), when the drain tank 6 is slid further toward the back side of the base 5, the lower end of the ball chain 12 slides on the upper plate 6a as it is dragged in the direction of movement as the drain tank 6 moves. The joined member 12a of the ball chain 12 is formed in a spherical shape, so it slides smoothly on the upper plate 6a.

As shown in FIG. 7(c), when the opening 66a of the drain tank 6 is positioned vertically below the through hole 5d, the lower part of the ball chain 12 falls from the upper plate 6a into the opening 66a and is guided downward by the front and rear walls 61f. In particular, since the inclined wall 61b is inclined downward toward the bottom wall 61a, the lower part of the ball chain 12 is guided toward the bottom wall 61a. In addition, since the ball chain 12 has multiple joints and is more easily deformed partially than a conductor, in the state shown in FIG. 7(b), the upper half hangs down under its own weight and only the lower half is curved toward the rear, so the lower end is not dragged rearward beyond the through hole 5d. Therefore, when the opening 66a is positioned below the through hole 5d as shown in FIG. 7(c), it is possible to avoid a situation in which the lower end of the ball chain 12 is positioned rearward of the opening 66a and does not fall into the opening 66a.

As shown in FIG. 7(d), when the drain tank 6 is slid further to the rear side of the base 5 and stopped at the installation position, the ball chain 12 is no longer in contact with the drain tank 6 and is suspended vertically downward by its own weight. In this way, the electrode-type level switch 10, which is provided in a location below the flat open showcase 2 where it is difficult for an operator to work, does not need to be attached after the drain tank 6 is installed. Instead, the drain tank 6 is simply slid from the front side to the rear side of the base 5 to install it at the installation position while still attached to the mounting bracket 5c, which is the installation position. This makes it possible to easily place the ball chains 12, 13 on the first electrode arrangement section 61 and the second electrode arrangement section 62.

Next, using Figures 8(a) to (d), we will explain the state of the ball chain 12 when the full-water drain tank 6 is slid forward and pulled out from its installed position. Note that the ball chains 12 and 13 have substantially the same deformation state, so only the state of the ball chain 12 will be explained.

When the drain tank 6 reaches the full liquid level, it is necessary to pull it out from its installed position by grasping the front end 6F of the drain tank 6 and sliding it toward the front as shown in FIG. 8(a). At this time, the ball chain 12 is positioned on the bottom wall portion 61a and hangs down vertically.

As shown in FIG. 8(b), when the drain tank 6 is slid toward the front side of the base 5, the lower part of the ball chain 12 comes into contact with the inclined wall portion 61b on the rear side as the drain tank 6 moves, and the lower part of the ball chain 12 is pulled toward the front side and curved. In addition, since the inclined wall portion 61b is inclined upward from the bottom wall portion 61a, the lower part of the ball chain 12 is smoothly guided upward, and is pulled out of the opening 66a without getting caught on the periphery of the opening 66a.

In addition, since the joined member 12a of the ball chain 12 is formed in a spherical shape, as shown in FIG. 8(c), the lower end of the ball chain 12 slides smoothly on the upper plate 6a as it moves toward the front side of the drain tank 6. In addition, the first electrode placement portion 61 is a recess formed integrally with the upper plate 6a, and the slit 61c is made unable to pass through the joined member 12a, so that the ball chain 12 inserted into the opening 66a will not be placed in the storage space A outside the first electrode placement portion 61 through the slit 61c.

As shown in FIG. 8(d), when the drain tank 6 is slid further toward the front and the rear end 6B of the drain tank 6 is moved forward from the position where the ball chain 12 is suspended, the lower end of the ball chain 12 slides off the top plate 6a of the drain tank 6, and the ball chain 12, which was curved toward the front, hangs down vertically under its own weight.

As described above, the electrode-type level switch 10 according to the embodiment of the present invention is a liquid level detection device that can detect the liquid level by contacting the drain water D with the ball chains 12, 13 as detection bodies and electrodes inserted into the drain tank 6 through the openings 66a, 66b formed in the upper part of the drain tank 6 in which the drain water D is stored. The ball chains 12, 13 are flexible and suspended so as to hang down vertically downward. In this way, the ball chains 12, 13 are flexible, so that even if the ball chains 12, 13 come into contact with the drain tank 6 when the drain tank 6 is set in the installation position or removed from the installation position, the impact is mitigated, and the detection body including the electrodes is not damaged. Furthermore, even if the ball chains 12, 13 are deformed by contact with the drain tank 6 or the bottom plate 5b, they hang down by their own weight when inserted into the openings 66a, 66b, and are arranged in an appropriate position approximately perpendicular to the liquid level of the drain water D, making it easy to handle and enabling accurate detection of the liquid level.

In addition, since the detection body is a linear chain made by joining multiple joined members 12a, 13a, when the ball chains 12, 13 are suspended, the joined members 12a, 13a come into contact with each other due to their own weight, so the conductivity of the ball chains 12, 13 is appropriately maintained even after deformation. In addition, since it is easier to partially deform compared to linear members, it is possible to prevent the lower ends of the ball chains 12, 13 from moving to a position far away from the detection position in response to the movement of the drain tank 6.

In addition, since the multiple joined members 12a are spherical, the spherical surfaces of the joined members 12a are slippery when they come into contact with the drain tank 6, etc., making it easy for the ball chains 12, 13 to be inserted into the openings 66a, 66b.

In addition, since it includes ball chain 12 as a first detection body having a first electrode, and ball chain 13 as a second detection body having a second electrode, which is located at a position away from ball chain 12 to the right, the two electrodes are suspended by separate detection bodies that are away from each other, so that contact and entanglement between ball chain 12 and ball chain 13 can be easily avoided.

The ball chains 12, 13 are suspended from a mounting bracket 5c separate from the drain tank 6, and the drain tank 6 can be pulled out by moving the ball chains 12, 13 from the installation position where they are inserted into the openings 66a, 66b in a horizontal direction (front-back direction) that intersects with a predetermined horizontal direction (left-right direction). In other words, the drain water D stored in the drain tank 6 can be drained by pulling out the drain tank 6 from the installation position without removing the support member 11 from which the ball chains 12, 13 are suspended from the mounting bracket 5c using a tool such as a screwdriver, and the drain tank 6 can be pulled out horizontally toward the front from the installation position, preventing the ball chains 12, 13 lined up on the left and right from coming into contact with each other or becoming entangled.

In addition, a first electrode arrangement portion 61 and a second electrode arrangement portion 62 in which ball chains 12 and 13 are arranged are provided at positions corresponding to the openings 66a and 66b inside the drain tank 6, and the first electrode arrangement portion 61 and the second electrode arrangement portion 62 are formed in a box shape that opens upward from the bottom wall portion 61a and the side wall portions 61d, 61d and the front and rear wall portions 61f, 61f that serve as peripheral walls erected on the upper peripheral edge of the bottom wall portion 61a, and when the drain water D exceeds a predetermined liquid level, the drain water D can enter the first electrode arrangement portion 61 and the second electrode arrangement portion 62 from the slits 61c, 61c. In this way, the drain water D does not enter the first electrode arrangement portion 61 and the second electrode arrangement portion 62 until the drain water D reaches the predetermined liquid level, and the liquid level is not detected until the drain water D in the first electrode arrangement portion 61 and the second electrode arrangement portion 62 reaches the predetermined liquid level. This prevents the predetermined liquid level from being detected when the drain water D has not yet reached the predetermined liquid level due to rippling caused by vibration, and makes it possible to detect the predetermined liquid level when the ball chains 12 and 13 are inserted deeply into the drain tank 6.

For more details, for example, to be able to detect a predetermined liquid level (full-water level) without providing the first electrode arrangement portion 61 or the second electrode arrangement portion 62, it is necessary to arrange the lower ends of the ball chains 12, 13 near the upper plate 6a at the openings 66a, 66b. In this case, if the liquid level temporarily ripples as described above, the predetermined liquid level may be detected even if the predetermined liquid level has not been reached. Also, if the lower ends of the ball chains 12, 13 are arranged below the predetermined liquid level, the liquid level will be detected before the liquid is full, whereas if they are arranged above the predetermined liquid level, the drain water D may overflow without being detected, so the installation of the ball chains 12, 13 requires precision.

On the other hand, when the ball chains 12, 13 are placed on the first electrode placement section 61 and the second electrode placement section 62, after the storage space A reaches a predetermined liquid level, the first electrode placement section 61 and the second electrode placement section 62 reach a predetermined liquid level and a current flows between the ball chains 12, 13. Even if the lower ends of the ball chains 12, 13 are placed at a liquid level different from the predetermined liquid level (for example, at a position lower than the predetermined liquid level), the predetermined liquid level can be accurately detected, which makes it easier to perform installation work such as adjusting the length of the ball chains 12, 13 and adjusting the position of the lower ends. In addition, since the predetermined liquid level can be accurately detected without being affected by the installation status of the ball chains 12, 13, the vertical dimensions can be shortened while ensuring the capacity of the drain tank 6.

In addition, the side walls 61d, 61d and the front and rear walls 61f, 61f of the first electrode placement section 61 and the second electrode placement section 62 are inclined outwardly in the upward direction, so that when the ball chains 12, 13 are inserted into the openings 66a, 66b or pulled out from the openings 66a, 66b, they are guided by the side walls 61d, 61d and the front and rear walls 61f, 61f, making them less likely to get caught on the vertical wall 61e, etc.

In the above embodiment, the detection body of the electrode-type level switch is a ball chain 12, 13 formed in a chain shape by rotatably joining multiple joined members 12a, 13a with joining members 12b, 13b. However, the present invention is not limited to this. For example, as shown in FIG. 9(a), a chain 24 may be used in which multiple conductive annular members 24a (joined members) are joined together to form a line.

Also, for example, as shown in FIG. 9(b), a hanging body 25 may be used, which comprises a conductive conductor 25a and a substantially spherical, conductive, and heavy weight 25b attached to the lower end of the conductor 25a. In this way, the detection body may be made of a flexible linear member such as the conductor 25a. Furthermore, since weight 25b is attached to the lower end, even if the conductor 25a is deformed, it will hang vertically downward due to weight 25b.

Although the embodiments and modifications of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention includes modifications and additions that do not deviate from the gist of the present invention.

In the above embodiment, the detection body is exemplified as a form in which the ball chains 12, 13 also serve as electrodes, but the present invention is not limited to this. For example, the detection body may have an electrode that is in electrical contact with the liquid to be detected, and the conductor may be covered with an insulator and partly exposed.

In addition, in the above embodiment, the detection body is flexible over its entire length, but the present invention is not limited to this. For example, it is sufficient that at least the portion of the detection body that is inserted into the container is flexible.

In the above embodiment, the detection body is fixed separately by ball chain 12 (first detection body) as an earth electrode and ball chain 13 (second detection body) as a detection electrode, but the present invention is not limited to this. For example, the first conductor having the first electrode and the second conductor having the second electrode may be spaced apart by a certain distance to prevent them from coming into contact and shorting out, and may be integrally provided inside an insulating material such as a rubber tube.

In addition, in the above embodiment, the lower ends of the ball chains 12, 13 are illustrated as being positioned slightly above the bottom wall portions 61a, 62a, but the present invention is not limited to this. For example, the ball chains 12, 13 may be suspended so that their lower portions are placed on the bottom wall portions 61a, 62a. In this way, the ball chains 12, 13 can be easily positioned at the desired liquid level by simply placing their lower portions on the bottom wall portions 61a, 62a, without having to precisely adjust the length of the ball chains 12, 13 to match the desired liquid level.

In the above embodiment, the support member 11 is not removed from the mounting bracket 5c of the base 5 when the drain tank 6 is pulled out from the installation position to drain the drain water, but the present invention is not limited to this. For example, when the drain tank 6 is pulled out from the installation position, the support member 11 may be removed from the mounting bracket 5c and the ball chains 12 and 13 may be pulled out from the openings 66a and 66b of the drain tank 6. In addition, regardless of whether the drain tank 6 can be pulled out from the installation position, the support member 11 may be attached to and detached from the mounting bracket 5c for maintenance. In other words, the ball chains 12 and 13, which are the detection bodies of the present invention, are flexible and hang down vertically, so they are unlikely to be damaged even if they collide with the drain tank 6 when attached to or removed from the mounting bracket 5c, and they hang down vertically when inserted into or pulled out of the openings 66a and 66b, making them easy to handle, such as when attached or removed.

In the above embodiment, the first electrode placement portion 61 and the second electrode placement portion 62 each have two slits 61c, 61c of a generally rectangular shape in plan view formed on the front and rear sides of the inclined wall portion 61b, but the present invention is not limited to this. For example, the shape can be changed to various shapes such as a generally square shape in plan view or a generally circular shape in plan view, in addition to the generally rectangular shape in plan view as described above. The number of slits 61c is also not limited to two, and may be one or three or more. Furthermore, in the above embodiment, the slits 61c, 61c are formed on the front and rear ends of the inclined wall portion 61b, but the present invention is not limited to this. For example, the location of the slits 61c, 61c may be changed to any location on the peripheral wall portion, such as approximately the center position in the vertical direction of the inclined wall portion 61b, depending on the desired liquid level.

In the above embodiment, a partition 63 having a generally inverted V shape in vertical cross section is formed between the first electrode placement section 61 and the second electrode placement section 62, and is composed of the side walls 61d, 61d of the first electrode placement section 61 and the second electrode placement section 62 and the upper plate 6a between the side walls 61d, 61d. However, the present invention is not limited to this. For example, the upper plate 6a between the side walls 61d, 61d may be extended horizontally to form a partition having a generally trapezoidal shape in side view.

In addition, in the above embodiment, the electrode-type level switch 10 as a liquid level detection device is applied to a refrigerated showcase 1, but the present invention is not limited to this. For example, the switch can be applied to a freezer showcase, or other commercial equipment other than a freezer or refrigerated showcase, or home appliances such as a humidifier or dehumidifier, and the liquid level detection device can detect the liquid level of a liquid to be detected other than drain water.

1 Refrigerated showcase 2 Flat open showcase 5 Base 6 Drain tank (container)
10 Electrode type level switch (electrode type liquid level detection device)
11 Support member 12, 13 Ball chain (detection body, electrode)
12a, 13a: members to be joined 12b, 13b: joining member 24: chain (detection body, electrode)
25 Hanging body (detection body, electrode)
61: First electrode arrangement portion 62: Second electrode arrangement portion 61a, 62a: Bottom wall portion 61b, 62b: Inclined wall portion 61c: Slit 61d, 62d: Side wall portion (peripheral wall portion)
61f, 62f Front and rear walls (peripheral wall)
61e, 62e Vertical wall portion 63 Partition portion 66a, 66b Opening 90 Overflow pipe A Storage space D Drain water (detected liquid)

Claims (8)

A liquid level detection device capable of detecting a liquid level by contacting an electrode of a detection body inserted into a drain tank through an opening formed in an upper portion of the drain tank with the drain water,
The detection body is flexible and suspended from a predetermined member separate from the drain tank so as to hang down vertically downward,
an electrode arrangement portion in which the electrode is arranged and communicates with the inside of the drain tank is provided at the opening , the electrode arrangement portion being formed in a box shape having a bottom wall portion and a peripheral wall portion standing on an upper peripheral edge of the bottom wall portion and opening upward from the bottom wall portion ;
The liquid level detection device is characterized in that the drain tank can be pulled out by moving it horizontally together with the electrode arrangement portion . The liquid level detection device according to claim 1, characterized in that the detection body is a chain made by joining multiple conductive members to be joined into a linear shape. The liquid level detection device according to claim 2, characterized in that the multiple joined members are spherical and joined by linear joining members. The liquid level detection device according to any one of claims 1 to 3, characterized in that the detection body includes a first detection body having a first electrode, and a second detection body arranged at a position separated from the first detection body in a predetermined horizontal direction and having a second electrode. The first detection body and the second detection body are suspended by a predetermined member separate from the drain tank,
The liquid level detection device according to claim 4, characterized in that the drain tank can be pulled out by moving it from an installation position where the first detection body and the second detection body are inserted into the opening in a specific horizontal direction that intersects with the specified horizontal direction. 6. The liquid level detection device according to claim 1 , wherein the electrode arrangement portion is configured to allow the drain water to enter into the electrode arrangement portion when the liquid level of the drain water reaches a predetermined liquid level. 7. The liquid level detection device according to claim 1, wherein an inner surface of the peripheral wall of the electrode arrangement portion is inclined outwardly as it extends upward. The liquid level detection device according to any one of claims 1 to 7, characterized in that a mounting member on which the electrode can be placed is provided between the opening inside the drain tank and the bottom wall of the drain tank.

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