JP2014010055A - Liquid level sensor and environment testing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid level sensor and an environment testing device capable of detecting a liquid level at positions in multiple levels different in a height direction while suppressing production costs.SOLUTION: An optical type liquid level sensor includes a plurality of light emission members 27 and light reception members 28. The plurality of light emission members 27 and light reception members 28 are disposed on a control board 32 on which a microcomputer 34 is loaded such that an optical sensor forming body 18 is formed. The optical sensor forming body 18 is incorporated in a container section 17 with which a prism 16 is integrally formed. Then, the light emission members and light reception members are set in a positional relation that when irradiation light from the light emission members 27 is reflected by the prism 16, the reflected light can be received by the light reception members 28 at positions different in a height direction.

Description

  The present invention relates to a liquid level sensor that detects a liquid level of a liquid stored in a predetermined space, and an environmental test apparatus including the liquid level sensor.

  As a device for testing the performance and durability of equipment, parts and the like (sample body), an environmental test device is provided on the market. For example, Patent Document 1 discloses a device called a constant temperature and humidity device (a type of environmental test device) that mainly tests durability against changes in temperature and humidity. Usually, a constant temperature and humidity device is provided with a heater, a cooling device, and a humidification device, and creates a desired environment toward a preset target temperature and target humidity.

By the way, in a constant temperature and humidity apparatus, the fixed test environment formed in the store | warehouse | chamber may be maintained over a long period of time. In particular, when a high-humidity test environment is formed, humidification control of the humidifier is continued for a long time. That is, when humidification control is performed over a long period of time, a large amount of water is consumed in the humidifier. Therefore, the constant temperature and humidity device is provided with a humidification water supply function for supplying water to the humidification device. And the constant temperature and humidity apparatus is equipped with the water storage tank in order to fulfill this humidification water supply function. In other words, the humidifier maintains a certain amount of water by the water supplied from the water storage tank, so that appropriate humidification control is maintained.
For example, Patent Literature 1 discloses such a technique.

  However, during the environmental test, both the amount of water in the water storage tank and the amount of water in the humidifier become insufficient, and there is a risk that the desired humidity environment cannot be formed or maintained. . Therefore, in the constant temperature and humidity device, the amount of water in the water storage tank must always be maintained at a predetermined amount or more. That is, this type of constant temperature and humidity device is provided with water level detecting means (hereinafter simply referred to as a water level sensor) for detecting the water level in the water storage tank. For this reason, in the constant temperature and humidity device, the water level in the water storage tank is monitored by the water level detection means, and water is replenished to the water storage tank when conditions such as a drop below a certain water level are met.

  Conventionally, in the thermo-hygrostat, an optical type or a float type is frequently used for reasons such as relatively low cost.

JP-A-8-23960

  However, the optical water level sensor can be introduced at a relatively low cost for the purpose of detecting a specific position, for example, in the case of “only two points of the upper limit water level and the lower limit water level need to be detected”. In the case of “I want to detect not only the upper limit water level and the lower limit water level but also the intermediate water level between them”, there is a complaint that the cost is increased. In other words, this optical water level sensor must increase the number of sensors that follow the increase in the number of water levels to be detected. The increase in cost was inevitable.

  In addition, the float type water level sensor has the same problem that the production cost increases, and there is a complaint that the water level width that can be detected is limited. In other words, this float type water level sensor is affected by the size of the float that contributes to the detection of the water level, and the water level interval that can be detected must be increased unnecessarily, so that the water level that can be detected is limited. I had it at the same time.

  Therefore, a method of adopting another type of water level sensor is considered. For example, there are a capacitance type sensor, an electric resistance type sensor, and a pressure type sensor that can detect the water level at a plurality of positions.

  However, since the water for humidification used in the constant temperature and humidity device is pure water that does not substantially contain salts or the like, a capacitance type or electric resistance type water level sensor is not suitable. On the other hand, the pressure-type water level sensor can be said to be a desirable sensor because it can continuously detect the water level, but it is very expensive in the first place, and it is difficult to adopt from the viewpoint of cost.

  Therefore, in view of the problems of the prior art, the present invention has an object to provide a liquid level sensor and an environmental test apparatus that can detect the water level at a plurality of different positions in the height direction while suppressing the production cost. To do.

  The invention according to claim 1, which is provided to solve the above-described problem, is a liquid level sensor that detects a liquid level by a light emitting member and a light receiving member, and includes at least an upper part of the plurality of light emitting members and the light receiving members. The removed portion has a waterproof structure and an optical element portion capable of reflecting light based on at least the refractive index of the inner and outer media, and the container portion includes a plurality of light emitting members and light receiving members. In addition, the optical element portion is arranged integrally or detachably so as to be convex with respect to the inner wall or the outer wall of the container portion, and the plurality of light emitting members are arranged at different positions in the height direction. In addition, the plurality of light receiving members are arranged at different positions in the height direction, and the light emitting member and the light receiving member corresponding to the positions in the height direction correspond to the case where the light emitted from the light emitting member is reflected by the optical element unit. The light receiving member can receive light A liquid level sensor, characterized in that it is a location relationship.

Here, a conventional optical liquid level sensor will be briefly described.
Some optical liquid level sensors utilize the difference in refractive index of a medium through which light passes. That is, it is a liquid level sensor provided with a prism. The prism refracts or reflects light depending on conditions such as the incident angle of light and the medium of the environment in which it is placed. That is, in this type of liquid level sensor, the liquid level is detected by irradiating the prism with light and checking whether the light is reflected or refracted by the prism. Such a liquid level sensor has one light emitting member, one light receiving member, and one prism, each of which forms one unit. For this reason, if this type of liquid level sensor is used to detect the water level at different levels in the height direction, one sensor having the same configuration must be provided at each height position. There is. Therefore, conventionally, as the number of water levels to be detected increases, the number of sensors to be installed increases, so an increase in production cost is inevitable.

  Therefore, the liquid level sensor of the present invention is configured by incorporating a plurality of light emitting members and light receiving members in one container part, and the liquid level sensor at a plurality of positions different in the height direction can be detected by the one sensor. It is possible. That is, the liquid level sensor of the present invention has a plurality of light emitting members and light receiving members arranged at different positions in the height direction in the container portion. Furthermore, in this liquid level sensor, an optical element part is arranged in the container part in order to reflect or refract each light emitted from each light emitting member incorporated in the container part. Therefore, the liquid level sensor of the present invention has a configuration in which a plurality of light emitting members and light receiving members, and an optical element portion are integrally formed by one container portion.

As described above, according to the present invention, one liquid level sensor is formed of a plurality of light emitting members and light receiving members, an optical element portion, and a container portion that makes them “a group”. Even when it is desired to detect the liquid levels at a plurality of positions as in the prior art, it is not necessary to provide the same number of sensors as the number of stages. As a result, according to the present invention, it is possible to provide a liquid level sensor capable of detecting the liquid level at a plurality of positions different in the height direction without causing a significant increase in production cost.
Furthermore, in the present invention, since the container portion and the optical element portion are integrally formed, the number of members can be reduced and the cost required for the member management can be reduced, so the production cost can be reduced more effectively. be able to.

  In the present invention, since the light emitting member and the light receiving member are built in the waterproof container, the liquid level sensor can be arranged directly in the liquid. That is, according to the present invention, it is not necessary to provide a space for arranging the liquid level sensor inside and outside a tank or the like for storing liquid, so that the versatility is high and the usability is also good.

  In the liquid level sensor of the present invention, the optical element portion extends in a protruding shape along the height direction of the container portion outside the container portion, and each of the plurality of light emitting members and light receiving members includes It is desirable that they are arranged along the extending direction of the optical element portion. (Claim 2)

  The invention according to claim 3 is characterized in that the plurality of light emitting members and light receiving members are provided on one control board and are electrically connected to a control unit mounted on the control board. The liquid level sensor according to claim 1 or 2.

  According to such a configuration, a plurality of light emitting members and light receiving members are provided on one control board, and are electrically connected to the control unit mounted on the control board, so that connection with an external device is simple. It becomes. That is, when each light emitting member or light receiving member is connected to the control unit provided on the control board and the control unit is connected to an external device, each light emitting member or light receiving member is connected to the external device. As a result, the number of wirings that are passed to the outside can be substantially omitted.

  Invention of Claim 4 is equipped with at least a humidifier and a water storage tank, The environmental test apparatus which can supply the water of the said water storage tank to a humidification apparatus WHEREIN: The liquid level sensor in any one of Claims 1-3 is equipped. And an environmental test apparatus characterized in that the water level information in the water supply tank can be acquired by the liquid level sensor.

  In order to detect the water level of the water storage tank, the environmental test apparatus of the present invention is a liquid level formed by a plurality of light emitting members and light receiving members, an optical element portion, and a container portion that makes them “a group”. Since the sensor is provided, it is not necessary to provide the same number of sensors as the number of stages even when it is desired to detect the water level at a plurality of stages as in the prior art. As a result, it is possible to provide an environmental test apparatus capable of detecting liquid levels at a plurality of positions without causing a significant increase in production cost.

  In the liquid level sensor and the environmental test apparatus of the present invention, one sensor is formed by a plurality of light emitting members and light receiving members, an optical element portion, and a container portion that makes them “a group”. Therefore, it is possible to detect the liquid level at a plurality of positions different in the height direction with one sensor, and it is possible to significantly reduce the production cost compared to the case of using a conventional optical liquid level sensor. Is possible. In the present invention, since the light emitting member and the light receiving member are arranged inside the waterproof container, the sensor can be directly arranged in the liquid, and the versatility and the feeling of use can be improved. .

It is a perspective view which shows the liquid level sensor with which the environmental test apparatus of FIG. 7 was equipped. It is a disassembled perspective view which shows the liquid level sensor of FIG. It is sectional drawing which shows an optical container body. It is explanatory drawing which shows the condition which is detecting the liquid level with a liquid level sensor. It is explanatory drawing which shows the locus | trajectory of light when light reflects in a prism. It is explanatory drawing which shows the locus | trajectory of the light when light is not reflected but permeate | transmitted in a prism. It is a conceptual diagram which shows the environmental test apparatus which concerns on embodiment of this invention. It is a perspective view which shows the modification of an optical container body. It is a perspective view which shows the modification of an optical sensor formation body. It is a modification of a liquid level sensor, and is explanatory drawing which shows the state which attached the optical sensor formation body of FIG. 9 to the optical container body of FIG. It is a perspective view which shows the liquid level sensor which can isolate | separate a container part and a prism.

Below, the liquid level sensor 3 which concerns on embodiment of this invention is demonstrated.
The liquid level sensor 3 of the present embodiment is an optical liquid level sensor that can detect water levels at a plurality of positions having different heights. And the liquid level sensor 3 of this embodiment has the prism (optical element part) 16, the container part 17, and the optical sensor formation body 18 incorporated in the container part 17, as shown in FIG. The optical sensor forming body 18 can be inserted into and removed from the container portion 17.

  The prism 16 employed in the present embodiment is formed of a transparent member such as polyester resin, and the liquid of the medium of the prism 16 is larger than the refractive index of air and stored in the water supply tank 41. In other words, it is an optical member having a refractive index substantially equal to that of water. As shown in FIGS. 2 and 3, the prism 16 has a triangular cross-sectional shape, and is a long member that extends in a direction orthogonal to the triangular cross-section. More specifically, the prism 16 of the present embodiment has a length in the longitudinal direction set to be approximately the same as the height of the container part 17 described later, and is formed integrally with the container part 17 described later. The optical container body 20 is formed.

  The container part 17 is a resin member such as a polyester resin like the prism 16 and is formed so that the appearance thereof is a rectangular parallelepiped as shown in FIGS. In addition, since the container part 17 is used with the attitude | position in which the longitudinal direction length follows a height direction, below, the longitudinal direction of the container part 17 is expressed as a height direction. And the container part 17 is provided with the bottomed space 26 by which the height direction upper part was open | released. That is, the container part 17 has the four side walls 45 and the one bottom wall 46, and these are connected without gap, and the bottomed space 26 which is surrounding space is formed. In other words, the container portion 17 has a waterproof structure that cannot be submerged in the bottomed space 26 except for the upper open portion. Moreover, the opening shape of the bottomed space 26 is substantially rectangular, and the opening size is set to a predetermined size.

  A pair of side walls 45 a and 45 c facing each other among the four side walls 45 a to 45 d, and the surfaces (inner wall surfaces) on the bottomed space 26 side are close to each other toward the bottomed space 26. An engaging protrusion 33 is provided in a protruding manner. The engagement protrusion 33 is constituted by a pair of projecting walls 47 a and 47 b extending along the height direction of the container portion 17. In other words, the engagement protrusion 33 is formed by arranging two protrusion walls 47a and 47b in parallel with each other at a predetermined interval. The distance between the two protruding walls 47a and 47b is set to be approximately the same as or slightly larger than the thickness of the control substrate 32 of the optical sensor forming body 18 described later.

The optical sensor forming body 18 has a configuration in which a light emitting member 27 and a light receiving member 28 are provided on a control board 32 on which a microcomputer 34 is mounted.
The light emitting member 27 includes a light emitting element that emits light when energized. In this embodiment, an LED (Light Emitting Diode) that emits infrared light is employed.
The light receiving member 28 includes a light receiving element that converts an optical signal or light energy into an electric signal or electric energy. In this embodiment, a phototransistor is employed.
The control board 32 is a rectangular board having a length approximately equal to the length of the container portion 17 in the height direction, and is formed by fixing a microcomputer 34 to a so-called printed wiring board by soldering or the like. . The control board 32 receives the light receiving member 37 for fixing a plurality (five in the present embodiment) of the light emitting members 27 and the light receiving members 28 for fixing a plurality (preferably the same number as the light emitting members). A connector 39 that enables electrical connection between the member arranging portion 38 and an external device is provided.

  In the liquid level sensor 3 of the present embodiment, the control substrate 32 of the optical sensor forming body 18 is formed in a predetermined space 26 in the bottomed space 26 of the container unit 17 so that each member as a constituent member forms the liquid level sensor 3. It is arranged to be in a posture. Specifically, the control board 32 is arranged in the bottomed space 26 so that the longitudinal direction thereof is along the height direction of the container part 17, and further, the end in the direction (width direction) orthogonal to the longitudinal direction. The portion is engaged with an engaging protrusion 33 provided on the container portion 17. More specifically, the control board 32 is sandwiched and fixed by two projecting walls 47a and 47b forming the engaging protrusions 33 at the position of the end in the width direction. At this time, a plurality (five in the present embodiment) of the light emitting members 27 and the light receiving members 28 fixed on the control board 32 are arranged in a region where the prism 16 exists. More specifically, each light emitting member 27 is arranged so that the prism 16 is positioned in the light irradiation direction, and each light receiving member 28 is irradiated by any one of the light emitting members 27 and adjacent to the prism 16. It is arranged at a position where it can receive light (reflected light) reflected by two surfaces (inclined surfaces R, S).

Then, the function of the liquid level sensor 3 of this embodiment is demonstrated.
As described above, the liquid level sensor 3 of the present embodiment has a function capable of detecting liquid levels at a plurality of different height positions (hereinafter referred to as a “multiple liquid level detection function”). In order to perform the multiple liquid level detection function, a plurality of light emitting members 27 and light receiving members 28 are provided on one control board 32. That is, in the liquid level sensor 3 of the present embodiment, the light emitting member 27 emits light at different height positions, and whether or not the light can be received by the light receiving member 28 is confirmed.

  For example, as shown in FIG. 4, when the liquid level sensor 3 is disposed in a tank 55 filled with water (liquid) up to a predetermined water level, the light emitting member 27 emits light at a position above the water surface. As shown in FIG. 5, when the light enters the prism 16, it is reflected by two adjacent inclined surfaces R and S and received by the light receiving member 28. More specifically, at a position above the water surface, the light incident on the prism 16 (incident light u) first reaches the inclined surface R. The inclined surface R is external air (the medium of the prism 16). (Refractive index> refractive index of air medium) and the interface is formed, and the incident light u is reflected in a direction rotated approximately 90 degrees counterclockwise with respect to the incident direction (first reflected light v). Then, the first reflected light v travels toward the inclined surface S adjacent to the inclined surface R and is reflected again by the inclined surface S. That is, since the inclined surface S forms an interface with external air like the inclined surface R, the first reflected light v is reflected in a direction rotated approximately 90 degrees counterclockwise with respect to the traveling direction. (Second reflected light w). Then, the second reflected light w is emitted from the prism 16 and received by the light receiving member 28. Then, as described above, the light receiving member 28 generates some electrical signal based on the optical signal. Therefore, since the electrical signal is generated when the light receiving member 28 receives the light from the light emitting member 27, the presence / absence of water at the height position can be determined by using the electrical signal.

  On the other hand, at a position below the water surface, when the light emitted from the light emitting member 27 is incident on the prism 16, it is not reflected by the inclined surfaces R and S, and no light is received by the light receiving member 28. More specifically, at a position below the water surface, the light (incident light u) incident on the prism 16 reaches the inclined surface R as shown in FIG. Due to the relationship of the refractive index of the prism 16 ≈ the refractive index of water, the interface formed by (1) emits the incident light u as it is without being reflected by the interface. That is, since no light signal is input to the light receiving member 28, no electrical signal is generated. Therefore, since the electrical signal is not generated unless the light receiving member 28 receives the light of the light emitting member 27, the presence or absence of water at the height is utilized by utilizing that the electrical signal is not generated. Can be judged.

In this embodiment, the electrical signals and the like are collected in the microcomputer 34 mounted on the control board 32. For example, some electric signal generated by the light receiving member 28 is input to the microcomputer 34 from a position above the water surface. Conversely, no signal is input from a position below the water surface. In the microcomputer 34, for example, the detection position where the electric signal is input is set as the signal a, and the detection position where the electric signal is not input is set as the signal b, and is output to an external electric device or the like. In the case of FIG. 4, the microcomputer 34 generates and outputs a signal such as “b · b · b · b · a” or “a · b · b · b · b”.
In this way, the liquid level sensor 3 of the present embodiment enables detection of water levels at a plurality of height positions.

  Further, in the liquid level sensor 3 of the present embodiment, a plurality of light emitting members 27 and light receiving members 28 are provided on the control board 32, and the control board 32 is provided on the optical container body 20 on which the prism 16 is integrally provided. On the other hand, it can be easily inserted and removed. That is, the liquid level sensor 3 of the present embodiment has a substrate replacement function that allows the control substrate 32 to be replaced. Therefore, the number of light emitting members 27 and light receiving members 28, the positions where the light receiving members 27 are fixed, and the like are changed. By changing to another control board 32, it is possible to easily change the number of liquid levels to be detected and the height of the liquid level.

Next, the environmental test apparatus 1 that can suitably use the liquid level sensor 3 of the present embodiment will be described.
The environmental test device 1 is a so-called constant temperature and humidity device, and has a constant temperature and humidity chamber 5 as shown in FIG. The constant temperature and humidity chamber 5 is divided into a test chamber 6 and an air conditioning passage 7 by a partition wall 8, and the test chamber 6 and the air conditioning passage 7 communicate with each other above and below the partition wall 8. Openings 9 and 19 are provided.

The test chamber 6 is a space in which a desired test environment is formed by arranging equipment and parts to be a sample when performing an environmental test, and an indoor temperature detecting means 23 for detecting the temperature of the space, and the space An indoor humidity detecting device 24 is provided for detecting the relative humidity.
The indoor temperature detection means 23 is a conventionally known temperature sensor such as a thermocouple or a resistance temperature detector, and detects a so-called dry bulb temperature.
The indoor humidity detection device 24 includes a conventionally known humidity detection sensor 29 and a wick 25 that covers a detection portion of the humidity detection sensor, and detects a so-called wet bulb temperature.

The air conditioning passage 7 is a portion that generates air having a desired temperature and humidity. The humidifier 10, the evaporator 11, the heater 12, and the blower 13 are arranged in order from the lower side (upstream side in the air flow direction). Has been.
The humidifier 10 has an evaporating dish (humidifying storage section) 30 having a predetermined depth and a conventionally known electric heater 31, and evaporates water stored in the evaporating dish 30 by the electric heater 31. It is.
The evaporator 11 is a part of a known cooling device and functions to take part of the refrigeration cycle. That is, the evaporator 11 is capable of changing the cooling capacity and the surface temperature through which the phase-change refrigerant flows.
The heater 12 is a conventionally known electric heater and heats air passing through the air conditioning passage 7.
The blower 13 is a conventionally known fan and forms a circulating air flow in the constant temperature and humidity chamber 5.

Moreover, the environmental test apparatus 1 of this embodiment is provided with a water supply system 15 for supplying water to the indoor humidity detection device 24 and the humidifier 10 in order to suitably form a humidity environment in the test chamber 6.
The water supply system 15 is provided with a water supply tank 41 capable of storing a predetermined amount of water. The water supply tank 41 is connected to the humidifier 10 and the detection water supply flow path 35 connected to the indoor humidity detector 24. The humidifying water supply channel 36 is configured. In the middle of each of the detection water supply channel 35 and the humidification water supply channel 36, water supply pumps 42 and 43 for pumping up water in the water supply tank 41 are provided.

  The above-described liquid level sensor 3 is provided in a water supply tank 41 that forms a part of the water supply system 15. More specifically, the liquid level sensor 3 of the present embodiment is so immersed as to be immersed in the water stored in the water supply tank 41 and so that the longitudinal direction of the optical container body 20 is along the height direction. It is arranged.

Next, the basic operation of the environmental test apparatus 1 will be described.
In the environmental test apparatus 1 of the present embodiment, as basic operations, there are a test environment forming operation for forming an environment in the test chamber 6 and an auxiliary operation for assisting the test environment forming operation.
First, the test environment forming operation will be described.
In the test environment forming operation, the air blower 13 is driven to form a circulating flow of air in the constant temperature and humidity chamber 5 in order to form a desired environment in the test chamber 6. Thereby, the air in the constant temperature and humidity chamber 5 is sucked by the blower 13 from the opening 19 on the lower side of the partition wall 8 to the air conditioning passage 7 side, passes through the air conditioning passage 7 vertically upward, and is partitioned. It is discharged from the opening 9 on the upper side of the wall 8 to the test chamber 6 side.

  Moreover, since the humidifier 10, the evaporator 11, and the heater 12 are arrange | positioned in order along the air flow direction in the air-conditioning channel | path 7 as mentioned above, it circulates in the constant temperature / humidity tank 5. The air is introduced into the air conditioning passage 7, is humidified as necessary by the humidifier 10, passes through the evaporator 11, flows to the heater 12 side, and is adjusted to a desired temperature and humidity. That is, in parallel with driving of the blower 13, the humidifier 10, the evaporator 11, and the heater 12 are controlled in the air conditioning passage 7 to generate air having a desired temperature and humidity. And the inside of the test chamber 6 is adjusted by the air produced | generated so that it may become the atmosphere of desired temperature and humidity.

Subsequently, an auxiliary operation will be described.
The auxiliary operation is an operation performed when a predetermined condition is satisfied, and is mainly a water supply operation for the indoor humidity detector 24 and the humidifier 10 and a replenishment operation for the water supply tank 41. That is, the auxiliary operation is an operation that can be performed in parallel with the test environment forming operation described above.

  The water supply operation is performed when there is a water supply request (hereinafter referred to as a detected water supply request) stored in the indoor humidity detection device 24 while the test environment formation operation is being performed, or when the humidifier 10 This is performed when there is a request for supplying humidifying water stored in the evaporating dish 30 (hereinafter referred to as a humidified water supply request).

  More specifically, when a predetermined amount of water is consumed in the wick 25 of the indoor humidity detection device 24 and a detection water supply request is generated, the water supply pump 42 is driven and the water in the water supply tank 41 is sucked out. Water is supplied to the humidity detector 24. Further, when a predetermined amount of water is consumed in the evaporating dish 30 of the humidifier 10 and a humidification water supply request is generated, the water supply pump 43 is driven, the water in the water supply tank 41 is sucked out, and water is supplied to the humidifier 10. Is done.

  Further, since the amount of stored water in the water supply tank 41 decreases with these water supply operations, water supply to the water supply tank 41, that is, a supply operation is performed as necessary. That is, the replenishment operation is performed when the water level information in the water supply tank 41 is acquired by the liquid level sensor 3 and the water level information satisfies a predetermined condition. In this embodiment, the water level at any height position that can be detected by the liquid level sensor 3 can be set as the reference water level, and the replenishment operation can be performed based on the set reference water level. More specifically, in the environmental test apparatus 1 of the present embodiment, the water level information acquired from the liquid level sensor 3 is compared with the set reference water level in a control device (not shown). If it is determined that the detected water level is below the reference water level, a replenishment operation is performed. For example, when the reference water level is set to the water level of the light emitting member 27 and the light receiving member 28 at the bottom of the liquid level sensor 3, the signal output from the liquid level sensor 3 is “b · b · b · If “b · a” or “a · b · b · b · b”, the replenishment operation is performed.

  As described above, in this embodiment, the optical sensor forming body 18 including the plurality of light emitting members 27 and the light receiving members 28 is disposed in the bottomed space 26 of the optical container body 20 integrally provided with the prism 16. Since the liquid level sensor 3 having the unit structure is formed, even when the liquid level is detected at a plurality of height positions, the cost is greatly reduced as compared with the case where a conventional optical liquid level sensor is employed. be able to.

  Further, in this embodiment, since the optical sensor forming body 18 can be inserted into and removed from the optical container body 20, even if it is desired to change the detection position or increase the detection position, for example, This can be easily achieved by changing the number and position of the light emitting members 27 and light receiving members 28 to be arranged. That is, since the change according to a use and the purpose can be performed easily, versatility is high and a usability is also good.

  In the present embodiment, since the plurality of light emitting members 27 and the light receiving members 28 are built in the container portion 17 having a waterproof structure, the liquid level sensor 3 can be disposed directly in the liquid. That is, according to the liquid level sensor 3 of the present embodiment, since it is not necessary to provide a space for arranging the liquid level sensor inside and outside a tank or the like for storing liquid, the versatility to an attachment device or the like is high. A feeling of use is also good.

  In the above embodiment, the optical container body 20 is shown in which the prism 16 is integrally provided so as to be convex toward the outside with respect to the outer wall surface of the container portion 17, but the present invention is not limited thereto, As shown in FIG. 8, an optical container body 62 in which the prism 16 is integrally provided so as to be convex toward the inner side with respect to the inner wall surface of the container portion 61 may be used. That is, the optical container body 62 has a configuration in which part of the inclined surfaces R and S of the prism 16 has entered the bottomed space 63 of the container portion 61. And when this optical container body 62 is employ | adopted, in order to acquire the effect similar to the said embodiment, it is desirable to employ | adopt the optical sensor formation body 65 (FIG. 9) provided with the structure shown below.

  That is, as shown in FIG. 9, the optical sensor forming body 65 has a configuration in which a plurality of light emitting members 27 and light receiving members 28 are provided on a control board 70 having three different surfaces. More specifically, the control board 70 has two separation walls 71 and 72 whose cross-sectional shape is deformed in a direction slightly away from each other on both sides of the “U” shape. A plurality of light emitting members 27 and light receiving members 28 are provided on inner surfaces of the two separating walls 71 and 72 facing each other. That is, in the optical sensor forming body 65, a plurality of light emitting members 27 are arranged in different height directions on one separating wall 71 side, and a plurality of light receiving members 28 are arranged on the other separating wall 72 side. Are arranged in the same height direction.

  Then, the optical sensor forming body 65 is arranged in the bottomed space 63 of the optical container body 62 to form the liquid level sensor 60 shown in FIG. The optical sensor forming body 65 disposed in the bottomed space 63 is arranged such that one separating wall 71 faces the inclined surface R of the prism 16 and the other separating wall 72 faces the inclined surface S of the prism 16. It has been arranged.

  Moreover, in the said embodiment, although the optical container body 20 which provided the prism 16 integrally in the container part 17 was shown, this invention is not limited to this, As shown in FIG. The optical container body 66 in which the prism 16 is detachable may be used. For example, the optical container body 66 is provided with a holding part (not shown) that holds the prism 16 outside the container part 17, and the prism 16 can be attached to the container part 17 via the holding part.

  In the above-described embodiment, the configuration in which the five light emitting members 27 and the light receiving member 28 are provided so that five levels of water levels can be detected in the height direction is shown, but the present invention is not limited to this and is less than five. Even if the light emitting member 27 and the light receiving member 28 are provided, six or more light emitting members 27 and the light receiving members 28 may be provided.

  In the above embodiment, a configuration is shown in which a plurality of light emitting members 27 and light receiving members 28 are provided on the control board 32 on which the microcomputer 34 is mounted, and each light emitting member 27 and each light receiving member 28 are connected to the microcomputer 34 by printed wiring. The present invention is not limited to this. For example, a plurality of light emitting members 27 and light receiving members 28 are provided on a board (not shown) that does not include a microcomputer, and wirings are individually connected to the light emitting members 27 and the light receiving members 28. It does not matter as a configuration.

  In the above embodiment, the configuration in which the liquid level sensor 3 is suitably arranged in an environmental test apparatus as a so-called constant temperature and humidity apparatus is shown, but the present invention is not limited to this, and the cold shock test apparatus as an environmental test apparatus is used. The liquid level sensor 3 may be arranged.

  In the environmental test apparatus 1 of the above embodiment, when the light emitted from the light emitting member 27 is not received by the light receiving member 28, it is determined that there is water at the height position, and conversely by the light receiving member 28. Although a configuration has been shown in which it is determined that there is no water at the height position when light is received, the present invention is not limited to this, and when no light is received by the light receiving member 28, water is at the height position. It may be determined that there is no water, and conversely, when light is received by the light receiving member 28, it may be determined that there is water at the height position.

  In the said embodiment, although the structure which detects the water level stored in the water supply tank 41 with the liquid level sensor 3 was shown, this invention is not limited to this, The structure which detects liquid levels other than water, such as a fuel. It does not matter.

  In the above-described embodiment, a configuration in which one long prism 16 having a length similar to the height of the container portion 17 is provided is shown. However, the present invention is not limited to this, and the prism of the above-described embodiment. A configuration using a plurality of short prisms shorter than 16 (the same number as the light emitting members or light receiving members or a smaller number thereof) may be used.

1 Environmental Test Device 3, 60 Liquid Level Sensor 6 Test Chamber 10 Humidifier (humidifier)
16 Prism 17, 61 Container part 18, 65 Optical sensor forming body 20, 62, 66 Optical container body 26, 63 Bottomed space 27 Light emitting member 28 Light receiving member 32, 70 Control board 34 Microcomputer (control part)

Claims (4)

A liquid level sensor that detects a liquid level by a light emitting member and a light receiving member,
A plurality of light-emitting members and light-receiving members, a container portion in which at least a portion excluding the upper portion has a waterproof structure, and an optical element portion capable of reflecting light based on at least the refractive index of the inner and outer media,
A plurality of light emitting members and light receiving members can be built in the container part, and the optical element part is arranged integrally or detachably so as to exhibit a convex shape with respect to the inner wall or the outer wall of the container part,
The plurality of light emitting members are arranged at different positions in the height direction, the plurality of light receiving members are arranged at different positions in the height direction, and the light emitting members and the light receiving members corresponding to the positions in the height direction are the light emitting members. A liquid level sensor characterized by being in a positional relationship that can be received by a light receiving member when light emitted from the light is reflected by an optical element portion.   The optical element portion extends in a raised shape along the height direction of the container portion outside the container portion, and each of the plurality of light emitting members and light receiving members extends along the extending direction of the optical element portion. The liquid level sensor according to claim 1, wherein the liquid level sensor is arranged.   3. The liquid according to claim 1, wherein the plurality of light emitting members and light receiving members are provided on one control board and are electrically connected to a control unit mounted on the control board. Position sensor. In an environmental test apparatus that includes at least a humidifier and a water storage tank and can supply water from the water storage tank to the humidifier,
An environmental test apparatus comprising the liquid level sensor according to claim 1, wherein water level information in the water supply tank can be acquired by the liquid level sensor.

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