JP2007333507A - Apparatus equipped with distance sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus equipped with a sensor for detecting distance, capable of improving measurement accuracy in a case that full water of drain water is detected by the distance detection sensor, and enabling easy inspection of a mounting position in a short period of time in a case that a water receiving condition is known and work need to be finished in a sort period of time, a case that only correctness of the mounting position of a water level sensor need to judged or the like when the apparatus is assembled in a showcase factory, or the like. <P>SOLUTION: The apparatus provided with the sensor for detecting distance by sending and receiving signal wave of acoustic signal, includes the distance detection sensor characterized by identifying the sensor mounting position based on time to receiving sending and receiving signal which is radiated for a fixed period of time. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for detecting a device provided with a distance sensor.

  As shown in FIG. 12, an open type vertical refrigerator-freezer showcase, which is an example of a device provided with a distance sensor, has a condenser 2 and a compressor (not shown) in a machine room 3 formed at the lower portion of the showcase body. The product stored in the product storage 1 is cooled by cold air cooled by a cooler installed on the back side of the showcase body, and the cold air is circulated. .

  As described above, the cool air is circulated in the cabinet, but since the front surface of the product storage 1 is opened as a product entrance, warm outside air flows from here, and moisture contained therein is Condensation occurs in the cooler and forms frost.

  And in order to prevent that the capacity | capacitance of a cooler falls by this frost formation, although it defrosts suitably, the defrosted water | moisture content generate | occur | produces as drain water.

  The drain water is usually connected to a drain pipe and led to a drain groove outside the store by this pipe. When the pipe is fixed, the installation position of the showcase is fixed by this pipe. Therefore, in a showcase in which a compressor is incorporated for easy movement, drain water is also stored in a drain water receiver 4 such as a drain tank or drain pan installed in the showcase so as not to impair mobility. .

  In this way, when drain water is stored in the drain water receiver 4, it is necessary to drain the water regularly. However, the amount of drain water generated depends on the weather, the size and temperature range of the showcase, It depends on the amount.

  For this reason, it is necessary to drain the drain water before grasping the storage amount of the drain water, and conventionally, the float 21 is provided as the water level sensor 20 to detect the storage amount. As shown in FIG. 13, when the float 21 floated on the drain water receiver 4 moves to a predetermined height along the float guide as the water level rises, the float 5 type water level sensor 20 is set at this height position. Press the contact 22 of a full water warning lamp lighting switch.

  As a result, the drain water full warning lamp 8 provided in the showcase controller 7 installed in the machine room 3 is turned on to notify the drain water receiver 4 that the drain water is full.

  By the way, the machine room 3 in which the drain water receiver 4 is disposed is limited in height due to the restriction that it is formed below the product storage 1 due to the structure of the entire showcase. It is necessary to keep the thickness as low as 20 mm to 40 mm.

  For this reason, the amount of movement of the float 21 is reduced, detection accuracy is difficult to be obtained, and a full water warning may be issued at a water level less than half of the full water storage amount. In order to cope with this, even if the installation of the float 21 is adjusted so that the detection accuracy is increased, the drain water is drained from the drain water receiver 4 because the float 21 is floated on the drain water receiver 4. Each time the float 21 is removed from the drain water receiver 4 and the installation is performed again. At this time, the installation position may be shifted, and it is difficult to ensure the detection accuracy.

  Furthermore, the float 21 is liable to break down during use because moss or dust adheres to it and the buoyancy changes or the movement of the movable part becomes smooth.

  There is also a method in which the drain water stored in the drain water receiver 4 is evaporated by an evaporator and released into the air. However, the performance of this evaporator also deteriorates due to dust adhesion in a short period of one or two years. In summer, when the amount of drain water is large, it cannot be treated with the evaporator alone, and it is necessary to use drainage work separately. Therefore, even when the evaporator is used, it is necessary to leave the drain water full.

Therefore, as a method for detecting the full water of the drain water by a non-contact method that is not mechanical, there is a method in which the ultrasonic sensor 9 is used as a water level sensor as shown in FIG. The sensor 9 is installed, and the distance between the ultrasonic sensor 9 and the water surface, that is, the water level is measured by measuring the time until the ultrasonic wave transmitted toward the water surface is reflected back to the water surface and received. Yes (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 3-195880

  The method of using the ultrasonic sensor 9 measures the time until the pulse signal transmitted from the transmission circuit unit which is the pulse oscillation unit of the ultrasonic sensor 9 is reflected by the water surface and returns to the reception circuit unit. The arithmetic processing circuit unit calculates the distance between the ultrasonic sensor 9 and the water surface, that is, the water level.

  However, in the machine room 3 in which the drain water receiver 4 is disposed, a condenser 2 and a compressor are installed. Air for cooling air generated from a cooling fan 5 for the condenser 2 and vibration of the compressor are provided. Accordingly, as shown in FIG. 14, waves are constantly generated on the surface of the drain water in the drain water receiver 4. For this reason, depending on the angle of the wave, the reflection direction of the ultrasonic wave may be converted, and the signal may not return to the receiving circuit unit of the ultrasonic sensor, resulting in a state in which distance measurement is impossible.

  Incidentally, when the distance between the ultrasonic sensor 9 and the water surface is set to 150 mm and the sampling interval is set to 20 msec, the distance measurement result of the ultrasonic sensor 9 is averaged as shown in FIG. 6 when there is no vibration. A measurement result of 150 mm is obtained, but when there is vibration of the compressor, the average measurement result is about 153 mm even though the wave height is actually ± 1 mm as shown in FIG. When the fan 5 is operating, the measurement result is about 170 mm on average even though the wave height is actually ± 3 mm as shown in FIG. 8, which is larger than the actual distance.

  In this regard, since the conventional example reflects the ultrasonic wave from the ultrasonic sensor with the float, the influence of the wave can be eliminated by increasing the weight and increasing the weight, but using the float. Inconvenience when the mechanical structure described above is employed cannot be solved.

  Further, due to the nature of the ultrasonic sensor, if the distance from the liquid surface is too far, the ultrasonic wave attenuates, and the measurement limit of the ultrasonic sensor in the case shown in FIGS. 6 to 8 is 255 mm. All the exceeding results are determined to be 255 mm.

  On the other hand, if it is too close, the received signal overlaps the transmitted signal, and in either case, the accurate distance cannot be measured, and the range in which the distance can be measured accurately is limited. FIG. 9 shows a case where the distance between the ultrasonic sensor and the water surface is closer (40 mm) than the measurable range (50 to 200 mm), and there are many variations in measurement results, and the distance is often determined to be 10 mm or less.

  As described above, even in the ultrasonic water level sensor which is a non-contact type used to compensate for the disadvantages of the conventional float type water level sensor, there is a problem that measurement accuracy cannot be obtained due to the influence of waves on the water surface. There is.

  When adopting an ultrasonic water level sensor in consideration of such circumstances, it is also possible to obtain measurement values by repeating measurement multiple times, or to obtain the average value of these multiple measurement values to increase measurement accuracy However, in this case, since the number of times of measurement increases, there is a disadvantage that it takes time to determine the distance.

  In particular, when assembling a showcase at the production stage of a factory or installing a showcase in a store, it takes a long time to obtain measurement results even though the water receiving condition of the drain water receiver is known. The fact that it is necessary impairs the workability of assembly and installation work that are required to be completed in a short time. In addition, when assembling or installing a showcase, it may be necessary to determine only whether or not the mounting position of the water level sensor is correct rather than an accurate water level. In such a case, it is useless to calculate the water level taking a long time. But there is.

  The object of the present invention is to eliminate the disadvantages of the conventional example described above, and to take advantage of the ultrasonic sensor and use it as a water level sensor to detect the fullness of the drain water stored in the drain water receiver. Sometimes it is possible to improve the measurement accuracy by measuring the distance based only on the data that can be measured accurately (reflection time until reflection and return), as well as when assembling at the showcase factory or at the store Refrigerated refrigeration that allows easy inspection of the mounting position in a short time, such as when installing a water tank and knowing the water receiving condition and wanting to finish the work in a short period of time, or when it is only necessary to determine whether the water level sensor is installed or not. To provide a showcase.

  In order to achieve the above-mentioned object, the present invention is characterized in that the invention according to claim 1 starts from a time until reception is performed by radiating a transmission / reception signal for a predetermined time in a device provided with a sensor for detecting a distance by a transmission / reception signal of an acoustic signal. It is an apparatus provided with a distance detection sensor characterized by confirming the sensor mounting position.

  As described above, the device provided with the distance detection sensor of the present invention is provided with a sensor for detecting a distance by a transmission / reception signal of an acoustic signal, and the sensor mounting position from the time until reception by emitting the transmission / reception signal for a predetermined time. For example, in order to detect the amount of drain water in a refrigerated showcase equipped with a drain water receiver, the measurement accuracy can be improved when the distance between the distance detection sensor and the liquid level is accurately measured. Is.

  If you want to obtain judgment results in a short time, such as when assembling or installing this equipment, while ensuring such high measurement accuracy, you can take this into account even if you reduce the number of reflection times. Since the water receiving state is known, there is no influence on the measurement accuracy, and it is possible to determine only whether or not the mounting position is required at the time of installation or assembly, thereby improving workability.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a flowchart showing the distance measurement operation of a drain water detection method for a refrigerator-freezer showcase as a device provided with a distance detection sensor of the present invention, and FIG. 5 is a drain water detection device as described above as a device provided with a distance detection sensor. Since the overall configuration of the showcase is the same as that of the conventional example described with reference to FIG. 12, the same reference numerals are assigned and detailed description thereof is omitted.

  The drain water detector in the present invention also uses the ultrasonic sensor 9 as a water level sensor, but the ultrasonic sensor 9 corresponds to the distance as shown in the output data conversion graph from the actual distance and the measurement result in FIG. The region where the output can be output is in the range of 50 mm to 200 mm.

  Therefore, the distance of 0 mm to 50 mm closer to this area and the distance of 200 mm to 255 mm are areas with no measurement accuracy. Therefore, if it is determined to be 50 mm or less, it is 50 mm, and if it is determined to be 200 mm or more, the distance is 200 mm. 10 mm is set as the distance data that is output when it is determined that the ultrasonic sensor 9 is close, and 30 mm is set as the distance data that is output when it is determined that the wave is large. When there is no response (reception) of sound waves and the distance is far outside the measurement, 255 mm is set as the distance data.

  FIG. 11 is a graph showing the relationship between the sensor determination distance and the number of output pulses. The distance 1 mm is replaced with one pulse.

  Here, the positional relationship between the drain water receiver 4 disposed in the machine room 3 and the ultrasonic sensor 9 will be described. The height of the machine room 3 is 300 mm as an example, and a range in which the distance can be normally measured by the ultrasonic sensor 9 can be secured. The ultrasonic sensor 9 and the drain water receiver 4 are disposed within the limited height range of the machine room 3, and the drain water receiver 4 is high in order to secure a distance from the ultrasonic sensor 9. For example, the thickness is low (thin depth is about 40 mm).

  The range of the ultrasonic sensor 9 can normally measure the distance between this limit level and the ultrasonic transmitter / receiver element of the ultrasonic sensor 9 by setting the lip of the drain water receiver 4 to the limit level at which drain water overflows ( The full water level is set 10 mm below (distance 80 mm) below this limit level.

  Next, the basic operation of drain water detection during the normal operation of the showcase will be described with reference to the flowchart of FIG. In this case, distance detection is performed, for example, to output distance data updated about every 10 seconds, and the sampling interval is set to 20 msec.

The reason for setting 10 seconds here is that, when the ultrasonic sensor 9 updates the data, if it is too long, the response to the water level change of the drain water becomes long and the usability is deteriorated. Moreover, if it tries to be quick, the detection accuracy of the distance mentioned later will worsen. Therefore, as the balance point, in this embodiment, updating is performed at intervals of 10 seconds.
In addition, the sampling interval of 20 msec was about 7 msec when the combination of the time required for the ultrasonic wave to reciprocate to the water surface and the longest processing time of the ultrasonic sensor 9 thereafter was found to be about 7 msec. 20 msec, and if the interval is about this, it was 2 msec for 100 measurements.

  If 20 msec has passed since the last distance measurement after 8 seconds (step 1) after the start of drain water detection (step 1), the distance to the drain water level is measured by the ultrasonic sensor 9 (step 3). ). As a result of the measurement, if the sound wave returns to normal and is received and measured within the measurement accuracy (50 to 200 mm) (step 4), it is determined whether or not the difference from the distance in the previous measurement is 20 mm or more. .

Here, the numerical value of 20 mm corresponds to 6 mm when converted to a peak value.
The reason for this setting is that, in a showcase that collects drain that is generally spread, even if the fan 5 is installed in the vicinity of the drain water receiver 4 and the fan 5 is rotated, the peak value of the wave generated in the drain water is about 3 mm. .
However, since the wave surface is a curved surface and the unevenness intensifies or weakens the ultrasonic reflected wave, the ultrasonic sensor 9 appears as a change of about 10 mm (about three times the influence) due to the influence.

  Therefore, the maximum peak value of the drain is 3 mm, and the detection by the ultrasonic sensor 9 is 10 mm. However, for some reason, the detection value by the ultrasonic sensor 9 may naturally be touched more greatly.

Therefore, as a determination as to whether or not this assumption is exceeded, for example, a peak value of 6 mm or more (20 mm or more for the ultrasonic sensor 9) that is twice the peak value that is normally generated is set.
As described above, when 20 mm or more is detected by the ultrasonic sensor 9, it is an unexpected factor influence, and thus this data is not adopted as data for detecting the reflection time.

On the other hand, if the measurement result within 20 mm is continued four times (step 5), (step 6), it is determined that it is in a stable state, and the current water level data is added to the value obtained by adding the previous water level data. Add (step 7).
Here, even if there is a wave on the surface of the drain water, it is possible to obtain 4 consecutive times because in Step 4, stable data is excluded by excluding non-measurement data. It becomes difficult to perform continuous coincidence four times, and as a result, a stable state cannot be determined, so that reliable distance measurement cannot be performed.

  If the number of additions reaches 128 (about 2.5 seconds) (step 8), it is determined that the distance measurement to the water surface has been completed normally, and the average of the addition values for 128 times is determined. Output data corresponding to the distance is created (step 9). In this case, since the sensor measurement range is 50 to 200 mm, if the deterministic value is outside this range, it is set to 50 or 200.

  Finally, distance data is output (step 10).

  By the way, when the distance measurement is not performed within the measurement accuracy in the step (step 4), the number of times the distance measurement cannot be performed has reached 128 times (about 2.5 seconds) (step 11). The number of data additions up to the previous time in (Step 7) is 32 times or more (Step 12), and the data in the normal measurable range has been taken so far. In this case, output data equivalent to 30 mm is created (step 13), and this distance data is output (step 13). 10).

  In addition, when the number of data additions up to the previous time has not reached 32 in the stage of (Step 12), since the determination outside the distance measurement continues stably, there is no drain water, etc. It is determined that the distance from the sensor 9 to the water surface is really far, that is, the distance to the water surface is outside the measurement, and output data corresponding to 255 mm set in advance in such a case is created (step 14). ), And outputs the distance data (step 10).

  On the other hand, if the number of data additions up to the previous time in (Step 7) has not reached 32 times (Step 15) even if 8 seconds have passed in the stage of (Step 1), the water surface and the ultrasonic sensor 9 It is determined that the measurement is impossible because the distance is too close due to the presence of obstacles between them, and in this case, output data equivalent to 10 mm is prepared (step). 16) This data is output (step 10).

  If the number of data additions up to the previous time is 32 times or more in the stage of (Step 15), the data in the normal measurable range has been taken so far. It is determined that the measurement is impossible due to the large or high value, and in this case, output data corresponding to 30 mm set in advance is created (step 13), and this distance data is output (step 10). ).

  Since distance measurement is performed based on data in the normal measurable range among multiple distance measurement data detected in this way, accurate results are obtained, and data outside the normal measurable range is also obtained. , Based on the number of times the sound wave does not return, the value that was actually measured, and the number of times, it is determined whether the cause is a long distance, short distance, or an unexpected wave has occurred it can.

  By the way, since it is unclear what the drain water is in the normal operation, the average value is determined by adding the water level data as many as 128 times continuously as described above. However, when the power is turned on such as when the showcase is assembled at the factory or when it is installed in the store, the worker knows the state of receiving the drain water and takes the usual time as described above. It is not necessary to detect the water level with high accuracy.

  The present invention takes such circumstances into consideration, and a first embodiment of a method for detecting drain water when power is turned on will be described with reference to the flowchart of FIG. In FIG. 1, the basic operation of drain water detection is the same as the operation according to the flowchart shown in FIG. 15, and the same step numbers are assigned.

  In the method of the present invention, the water level data is added a plurality of times (step 7). However, if one minute has passed since the power was turned on, such as during normal operation (step 17), the water level data is added up to 128 times. (Step 8), the average value is obtained to calculate the fixed distance (Step 9).

  On the other hand, when assembling a showcase in a factory or installing a showcase in a store, it is not necessary to detect the distance accurately, so within one minute after the power is turned on (step 17) when assembling a showcase in the factory. In such a case, the number of additions of the water level data is reduced, for example, 8 times (step 18), and the distance measurement to the water surface is normally completed with this small number of times. Judge.

  Then, the output data corresponding to the average value of the added values for the eight times is set as a determined distance (step 19). Thereby, it is possible to shorten the time for detecting the water level when assembling a showcase in a factory or installing a showcase in a store.

  FIG. 2 shows the second embodiment, and the basic operation is the same as the operation according to the flowchart shown in FIG. 15, and thus detailed description thereof is omitted here. Even in the second embodiment, the water level data is added a plurality of times (step 7), but within 1 minute after the power is turned on (step 20), the distance calculated based on the acquired water level data is set in advance. Only the distance, for example, whether it is far or close to 100 mm is determined (step 21). If it is far, the LED lamp is turned on to notify this (step 22). Notification is made (step 23).

  The reason for judging only whether the calculated distance is longer than or close to a predetermined distance, for example, 100 mm, is that the installation worker is responsible for the state of drain water when assembling or installing the showcase. The problem is whether the water level sensor and the drain water receiver are arranged in the correct positional relationship. Therefore, it is determined only whether the water level sensor and the drain water receiver are not too close or too far apart.

  FIG. 3 shows the third embodiment, and the basic operation is the same as the operation according to the flowchart shown in FIG. 15, and thus detailed description thereof is omitted here. Even in the second embodiment, the water level data is added a plurality of times (step 7). However, even if the water level data has not reached 128 times (step 8), if it is within 1 minute after the power is turned on (step 7). 24) Determining whether the difference between the shortest distance and the longest distance calculated based on the reflection times detected a plurality of times so far is within a predetermined value, for example, in the range of 3 mm, which can be determined that the water surface is stable (Step 25).

  As a result of the determination, if it is 3 mm or more, that is, if it is outside the predetermined range, it is determined that there is an abnormality, and output data corresponding to 5 mm set in advance assuming such a case is created (step 26).

  The reason for determining the water receiving state without waiting for the number of additions of 128 here is that it should be stable in the same state as the still water without wind normally within 1 minute after the power is turned on. Under these assumptions, when the water level is supposed to be in such a state, the difference in the height of the water surface is 3 mm or more is based on the determination that it is not an error even if it is determined as an abnormal state.

  FIG. 4 shows a fourth embodiment, in which power is supplied to the showcase when the showcase is installed (step 27). In this state, the blower fan, condenser, cooler, and compression provided in the showcase Stop all electrical equipment such as machines. The distance from the water surface of the drain water in the drain water receiver 4 is measured by the ultrasonic sensor 9 without being affected by the drive of such an electric device (step 28).

  After the distance measurement, the driving of the blower fan is started (step 29), and here, the distance from the water surface of the drain water is measured again (step 30). As long as the drain water receiver is installed in the correct position, it is assumed that it will not be greatly affected by the blower fan. As a result of the measurement, the difference in distance measured before and after driving the blower fan is within 3 mm. If there is (step 31), it is determined that the influence of the blower fan on the drain water is within an allowable range, the operation of the cooler is started (step 32), and the normal cooling operation is performed (step 33).

  On the other hand, if the difference in distance is 3 mm or more at the stage of (Step 31), it is determined that the influence of the wind by the blower fan is large and unexpected, and it is determined as abnormal. And the alerting | reporting corresponding to this abnormality is implemented (step 34).

  Note that the number of times and the time in the embodiment are not limited to the values shown here. In addition, the showcase is one form of the cooling / heating device, and the embodiment shows the showcase. Needless to say, however, the present invention is not limited to the showcase. For example, the storage amount detection of the dehumidifier is performed. Etc. can also be used.

It is a flowchart of a part of drain water detection operation | movement which shows 1st Embodiment of the apparatus provided with the distance detection sensor of this invention. It is a flowchart of a part of drain water detection operation | movement which shows 1st Embodiment of the apparatus provided with the distance detection sensor of this invention. It is a flowchart of a part of drain water detection operation | movement which shows 2nd Embodiment of the apparatus provided with the distance detection sensor of this invention. It is a flowchart of a part of drain water detection operation | movement which shows 2nd Embodiment of the apparatus provided with the distance detection sensor of this invention. It is a partial flowchart of the drain water detection operation | movement which shows 3rd Embodiment of the apparatus provided with the distance detection sensor of this invention. It is a partial flowchart of the drain water detection operation | movement which shows 3rd Embodiment of the apparatus provided with the distance detection sensor of this invention. It is a flowchart of the drain water detection operation | movement which shows 4th Embodiment of the apparatus provided with the distance detection sensor of this invention. It is a perspective view of the freezing and refrigeration showcase provided with the drain water detection apparatus which is an example of the apparatus provided with the distance detection sensor of this invention. It is a graph which shows the distance based on the received signal detected with an ultrasonic sensor when there is no vibration. It is a graph which shows the distance based on the received signal detected with an ultrasonic sensor in case there exists a vibration of a compressor. It is a graph which shows the distance based on the received signal detected with an ultrasonic sensor when the ventilation fan is act | operating. It is a graph which shows the distance based on the received signal detected with an ultrasonic sensor in case the distance of an ultrasonic sensor and a water surface is nearer than a measurable range. It is a sensor output data conversion graph from an actual distance and its measurement result. It is a graph which shows the relationship between a sensor determination distance and the number of output pulses. It is a perspective view of the refrigeration showcase provided with the drain water detection apparatus which is an example of the apparatus provided with the conventional distance detection sensor. It is a front view of the conventional drain water detection apparatus. It is a front view of the drain water detection apparatus when a wave generate | occur | produces on the water surface. It is a flowchart of a part of detection operation | movement which shows the general example of a drain water detection method. It is a flowchart of a part of detection operation | movement which shows the general example of a drain water detection method.

Explanation of symbols

  1 Product storage, 2 Condenser, 3 Machine room, 4 Drain water receiver, 5 Fan, 6 Evaporating plate, 7 Showcase controller, 8 Full water alarm lamp, 9 Ultrasonic sensor, 20 Water level sensor, 21 Float, 22 Full water alarm Lamp switch contact.

Claims (4)

In a device provided with a sensor for detecting a distance by a transmission / reception signal wave of an acoustic signal, a distance detection sensor is provided, wherein the sensor mounting position is confirmed from a time until it is received by radiating a transmission / reception signal for a predetermined time. machine. The device provided with the distance detection sensor according to claim 1, wherein the distance estimated from the time received at the predetermined time is compared with an arbitrarily determined distance, and the determination result is notified. 3. The apparatus provided with a distance detection sensor according to claim 2, wherein the determination is made after power is turned on and before drain water is generated. 4. The device provided with the distance detection sensor according to claim 2, wherein the determination is performed immediately after power-on.

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