JP4174464B2 - Clogging detection method for air circulation device, computer case and dust filter - Google Patents

Description

  The present invention relates to an improvement in a method for detecting clogging of an air circulation device, a computer casing, and a dustproof filter.

  As an air circulation device having a function of detecting clogging of a dustproof filter provided at an air intake port of an intake fan, for example, a warm air heating device with an air cleaner disclosed in Patent Literature 1 or Patent Literature 2 The disclosed air purifier is known.

Among these, the thing of patent document 1 comprises the air intake port of an air purifying fan with a dust-proof filter and a bypass air path, provided a shutter and a wind speed sensor in this bypass air path, and opened a shutter regularly and air. The clean fan is driven at the maximum air volume, and the clogging of the dustproof filter is detected based on the increase in the wind speed detected by the wind speed sensor. In other words, pay attention to the fact that the air resistance of the dustproof filter increases due to the occurrence of clogging, and the wind speed of the air on the bypass air passage side increases. Let's detect the occurrence of clogging of the dustproof filter based on the presence or absence of this increase in wind speed. That is the purpose.
However, when such a configuration is applied, it is necessary to periodically open the shutter in order to detect the occurrence of clogging of the dustproof filter. At this time, the outside air that does not pass through the dustproof filter is at a considerable wind speed. Since it will flow into the interior, if such a structure is used as a cooling means for a casing of a precision instrument such as a computer, there is a risk that the internal electrical components will be deteriorated or damaged. Further, since the wind speed sensor itself is also exposed to a high-speed external air flow, there are concerns about adverse effects such as adhesion of dirt to the wind speed sensor and deterioration in detection accuracy of the wind speed sensor.

On the other hand, in Patent Document 2, a main filter having a low air resistance and a sub filter having a relatively higher air resistance than the main filter are provided at the air intake port to distribute the inflow of air to each dustproof filter. An increase in the amount of air flowing into the sub-filter, that is, clogging of the main filter is detected by a pressure-sensitive switch provided on the sub-filter side.
When such a configuration is applied, a sub-filter is provided at the installation location of the pressure-sensitive switch, so that dirt is detected from the installation location of the detection means (wind speed sensor) as in the bypass air passage in Patent Document 1 described above. However, the main filter is not clogged until the amount of air flowing into the secondary filter increases to the extent that the pressure-sensitive switch installed in the secondary filter with high air resistance is activated. There is a problem that it is not.
Originally, this configuration should be used for home or in-vehicle air purifiers having a blower having a sufficient blowing capacity, and such a structure is used for a casing of a precision instrument such as a computer. If diverted to the cooling means, there is a concern about problems such as overload of the motor that drives the fan.
In addition, since the pressure-sensitive switch of the sub-filter is provided outside the sub-filter, that is, in a portion that is in direct contact with the outside air, similarly to the above, there is a problem such as deterioration in detection accuracy of the pressure-sensitive switch due to adhesion of dirt I can't escape.

JP 2000-320897 A (paragraph number 0019, FIG. 1) Japanese Patent Laid-Open No. 7-213840 (paragraph number 0013, FIG. 1)

  Therefore, an object of the present invention is to improve the inconvenience of the above-mentioned prior art, to prevent the sensor required for detecting the clogging of the dustproof filter from being easily soiled or deteriorated, and to provide a housing for precision equipment such as a computer. An object of the present invention is to provide an air circulation device that can also be used as a cooling means, and a clogging detection method for a computer case and dustproof filter provided with the air circulation device.

An air circulation device of the present invention includes an intake fan that sucks outside air into a housing, a dust-proof filter provided at an air intake port of the intake fan, and an air exhaust port that discharges air inside the housing to the outside. In order to achieve the above-mentioned problem,
An exhaust fan for exhausting the air in the housing to the outside is disposed at the air exhaust port, and an air suction port is provided in the housing so as to be separated from a position where the intake fan and the exhaust fan are disposed. Install a sensor to detect the inflow of outside air at the air inlet,
As the internal temperature of the housing rises, the amount of air transported by the intake fan and the exhaust fan both increases, and the outside air per unit time by the intake fan is not clogged in the dustproof filter. Storage means for storing in advance the air conveyance amount of the intake fan and the exhaust fan so that the intake amount and the amount of air discharged per unit time by the exhaust fan coincide with each other ;
Drive control of the intake fan and the exhaust fan is performed based on the relationship between the air conveyance amount of the intake fan and the exhaust fan stored in the storage means and the internal temperature of the housing, and the current value of the internal temperature of the housing. In addition, an allowable value corresponding to the current value of the internal temperature of the housing among the allowable values stored in the storage unit in advance corresponding to the internal temperature of the housing, and an outside air inflow rate detected by the sensor In comparison, the control device includes a control unit that detects occurrence of clogging in the dustproof filter when the inflow speed exceeds the allowable value .

With the above configuration, the intake fan takes in outside air into the housing through the dust filter, while the exhaust fan provided at the air discharge port exhausts the air in the housing to the outside, so that clean air is discharged into the housing. Circulate.
When the dust filter is not clogged, the amount of outside air taken into the housing by the intake fan and the amount of air discharged to the outside by the exhaust fan match, and the air pressure inside the housing becomes equal to the outside air pressure. Therefore, outside air does not flow into the housing through the air intake port of the housing. For this reason, the sensor provided at the air intake port of the housing is not exposed to the flow of air passing through the air intake port, and this sensor is located at a position away from the installation positions of the intake fan and the exhaust fan. Since it is installed, it is not directly exposed to the flow of outside air drawn into the housing by the intake fan or the flow of air discharged from the housing by the exhaust fan. Therefore, problems such as adhesion of dirt to the sensor and deterioration of detection accuracy of the sensor due to dirt are solved. At the same time, since the only outside air that is sucked into the housing is clean air that has passed through the dust-proof filter, problems such as deterioration and damage to electrical components inside the housing are also eliminated, including computers and the like It is suitable as a cooling means for the casing of precision equipment.
If the dust filter is clogged due to long-term use or use in a poor environment, the air resistance of the dust filter increases and the amount of outside air taken into the housing per unit time by the intake fan decreases. . However, since there is no change in the air exhaust capability of the exhaust fan, the air pressure inside the housing is relatively decreased compared to the outside air pressure, and the air pressure through the air inlet of the housing is compensated to compensate for this pressure difference. Outside air flows into the housing. A sensor installed at the air inlet detects the inflow of outside air from the air inlet as occurrence of clogging of the dustproof filter. In this way, the dust-proof filter is clogged based on the fact that the air pressure inside the housing, which has been kept dynamically equal to the outside air pressure, decreases due to the cooperative operation of the intake fan and the exhaust fan, and the outside air flows in from the air intake port. Since the detection is performed, it becomes possible to detect clogging of the dustproof filter at an early stage. As a result, the problem of overload of motors for driving the intake fans and exhaust fans is also improved, and it is also suitable as a cooling means for a casing of precision equipment such as a computer using a small motor as a drive source of these fans. .

  The air intake port may be provided on the same surface as the one surface of the housing provided with the air intake port (intake fan).

  In general, since the casing has a rectangular parallelepiped shape, the air sucked into the casing tends to flow in a laminar manner on the four surfaces orthogonal to the plane provided with the air intake port (intake fan). If an air suction port is provided, outside air may be sucked from the air suction port due to the air flow in the housing, and the sensor provided in the air suction port may be exposed to the air flow in the housing. is there. On the other hand, since there is a low possibility that air in the housing flows in a laminar flow on one side of the housing provided with an air intake (intake fan), it is effective for inhaling outside air due to the air flow in the housing. Can be prevented.

Furthermore, it is desirable to provide an abnormality display unit for displaying an abnormality when the occurrence of clogging by the control unit is detected.

As described above, in the present invention, the dust filter is clogged because the pressure inside the housing is reduced and the outside air flows from the air intake port. it is possible to discover in. The abnormality display section indicates an abnormality display that indicates the occurrence of clogging when the occurrence of clogging is detected by the control section, that is, when the inflow rate of outside air detected by the sensor exceeds a preset allowable value. I do.

  The computer casing of the present invention is a computer casing provided with the above-described air circulation device.

  As already mentioned, problems such as overloading of motors that drive intake fans and exhaust fans have been improved, and electric components that generate heat such as microprocessors and motherboards in the case using a small motor as the drive source for these fans In addition, since the air sucked into the housing is only clean outside air, problems such as deterioration and damage to electrical components inside the housing are also eliminated. .

  In a computer case equipped with an air circulation device, the computer case serves as a control unit that detects the occurrence of clogging by comparing the inflow rate of outside air detected by a sensor with a preset allowable value. A body microprocessor can be used, and a monitor of the computer casing can be used as an abnormality display unit that displays the occurrence of clogging as an abnormality.

  Since it is not necessary to separately provide a dedicated control unit and abnormality display unit in the air circulation device, the manufacturing cost of the entire device can be reduced.

Further, it is desirable that the control unit is configured to detect the occurrence of clogging when the outside air inflow velocity detected by the sensor exceeds an allowable value over a preset period .

By detecting the occurrence of clogging only when the outside air inflow velocity detected by the sensor exceeds the allowable value for a preset period, the enclosure due to momentary abnormal rotation of the intake fan or exhaust fan is detected. It is possible to prevent a decrease in the atmospheric pressure from being erroneously detected as clogging of the dustproof filter.

The clogging detection method of the dustproof filter in the present invention is a clogging detection method for detecting clogging that occurs in the dustproof filter disposed in the air intake port of the housing, and in order to achieve the same problem as described above,
An intake fan that takes outside air into the casing through the dust filter and an exhaust fan provided at the air discharge port of the casing are used together, and the air conveyance amount of the intake fan and the exhaust fan is determined based on the internal temperature of the casing. As the air pressure in the housing is increased so that the air pressure in the housing is equal to the external air pressure in a state where the dust filter is not clogged, clean air is circulated in the housing.
An inflow rate of outside air from an air intake port provided in the housing apart from the positions where the intake fan and the exhaust fan are disposed, and an allowable value set corresponding to a current value of the internal temperature of the housing When the inflow speed exceeds the allowable value , it is detected that clogging has occurred.

  The method or means for circulating clean air in the housing so that the air pressure in the housing is equal to the external air pressure when the dustproof filter is not clogged has already been described. Further, as described above, as a method or means for detecting the occurrence of clogging when the degree of inflow of outside air exceeds a predetermined range based on the degree of inflow of outside air from the air inlet, as described above, A sensor for detecting the inflow of outside air can be used.

The present invention uses an intake fan that takes in outside air through a dustproof filter and an exhaust fan provided at an air discharge port, so that the pressure inside the housing is equal to the outside pressure in a state where the dustproof filter is not clogged. In this way, clean air is circulated in the housing, and the occurrence of clogging in the dustproof filter is detected by a sensor installed at an air inlet provided at a position away from the positions of the intake fan and exhaust fan. Since the detection is based on the inflow of the outside air, the outside air does not flow into the housing through the air suction port when the dustproof filter is not clogged.
Therefore, the sensor is not exposed to the air flow through the air intake port, and the sensor is not directly affected by the flow of outside air sucked into the housing by the intake fan or the air flow discharged from the housing by the exhaust fan. The problem of adhesion of dirt to the sensor and deterioration of the detection accuracy of the sensor due to dirt is solved, and the outside air sucked into the housing is only clean air that has passed through the dustproof filter. Therefore, the problem of deterioration or damage to the electrical components or the like inside the housing is also solved.
Further, when the dust filter is clogged, the air resistance of the dust filter is increased and the air pressure in the housing is relatively lowered compared to the external air pressure, and flows into the housing through the air suction port of the housing. Since the sensor detects the flow of outside air as the occurrence of clogging of the dustproof filter, it is possible to detect clogging of the dustproof filter at an early stage, and problems such as overloading of the motor that drives the intake fan and exhaust fan are also improved. As a driving source for these fans, a small motor can be used.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a plan sectional view schematically showing an embodiment in which the clogging detection method and the air circulation device of the present invention are applied to a computer casing (hereinafter simply referred to as a casing), and FIG. It is the functional block diagram which simplified and showed the structure of the motherboard etc. provided with the microprocessor which functions as a control part of an air circulation apparatus.

The casing 1 has a rectangular parallelepiped shape as shown in FIG. 1, and an intake fan F1 for sucking outside air into the casing 1 and an intake fan F1 at a side end portion of one side surface 1a thereof. For this purpose, an air intake port 2 and a dustproof filter 3 are superposed.
Further, an air discharge port 4 is provided at a side end portion of the other side surface 1b facing the one side surface 1a, and the air in the housing 1 is forcibly discharged to the outside through the air discharge port 4. Exhaust fan F2 is provided.
As shown in FIG. 1, the intake fan F <b> 1 and the air intake port 2, the exhaust fan F <b> 2 and the air exhaust port 4 are substantially located on the diagonal line of the housing 1.

  In addition, an air suction port 5 is provided on one side surface 1a of the housing 1 (the same surface as the surface on which the air intake port 2 is provided) so as to be separated from the arrangement positions of the intake fan F1 and the exhaust fan F2. A sensor S <b> 1 is installed in the air inlet 5. The sensor S <b> 1 is for detecting the flow of outside air flowing in through the air intake port 5, and specifically has a configuration for detecting the wind speed of the outside air flowing in through the air intake port 5.

  The intake fan F1 is rotationally driven by the motor M1, and the exhaust fan F2 is rotationally driven by the motor M2.

  Reference numeral 6 denotes a mother board provided in the housing 1, and as shown in FIG. 2, at least a microprocessor (hereinafter simply referred to as a CPU) 7 as a calculation means constituting a main part of the computer, a ROM 8, and It has storage means such as a RAM 9, and further includes large-capacity storage means such as an interface 10 for connecting to an external device, an input / output circuit 11, and a hard disk drive 12.

  When the housing 1 is a notebook personal computer or the like, the monitor 13 and the keyboard 14 are integrated with the housing 1. When the housing 1 is an ordinary personal computer or a workstation, generally, a monitor is used. 13 and the keyboard 14 are configured separately from the housing 1. In any case, the monitor 13 also has a function as an abnormality display unit that displays the occurrence of clogging in the dust filter 3.

  The rotational speeds of the motors M1 and M2 of the intake fan F1 and the exhaust fan F2 are controlled by the CPU 7 via the input / output circuit 11 and the drivers 15 and 16, and the wind speed V detected by the sensor S1 is converted into an A / D converter. 17 is digitally converted and read into the CPU 7 via the input / output circuit 11.

  The temperature sensor S2 is provided on the mother board 6 to detect the internal temperature of the housing 1, and the detected temperature T detected by the temperature sensor S2 is digitally converted by the A / D converter 18, and the input / output circuit 11 is read into the CPU 7 via The temperature sensor S2 may be provided in the vicinity of the CPU 7, and the heat generation of the CPU 7 may be exclusively detected.

In this embodiment, in a state where the dustproof filter 3 is not clogged, the intake amount of outside air per unit time by the intake fan F1 and the discharge amount of air per unit time by the exhaust fan F2 are substantially matched. The air conveyance amounts of the intake fan F1 and the exhaust fan F2 are predetermined.
Specifically, the diameter of the intake fan F1 is made larger than the diameter of the exhaust fan F2 as shown in FIG. 1, and the rotational speed V _F1 of the intake fan F1 is set as shown in FIG. exhaust fan than the rotation speed V _F2 of F2 by set higher, the dust filter 3 to compensate for the loss of outside air intake amount caused by air resistance, per outside air intake amount and unit time per unit time of the air The amount of emissions is almost the same.
In addition to this, only the diameters of the intake fan F1 and the exhaust fan F2 are appropriately selected under the same other conditions, and only the pitches of the intake fan F1 and the exhaust fan F2 are appropriately selected under the same other conditions. The dust filter 3 is clogged by properly selecting only the rotational speeds V _F1 and V _F2 of the intake fan F1 and the exhaust fan F2 under the same conditions, or by a combination of two or more of these operations. It is possible to make the intake amount of the outside air per unit time and the discharge amount of the air per unit time substantially coincide with each other.

Furthermore, in this embodiment, in order to properly cool the electrical components such as the mother board 6 built in the housing 1, as shown in FIG. 3, the housing is in accordance with the detected temperature T detected by the temperature sensor S2. As the detected temperature T, which is the temperature inside the body, increases, the rotational speeds V _F1 and V _{F2 of} the intake fan F1 and the exhaust fan F2 are adjusted to increase.
As a result, the air conveyance amount per unit time in the intake fan F1 and the exhaust fan F2 increases according to the detected temperature T, but the intake amount of outside air per unit time is whatever the detected temperature T is. And the rotational speeds V _F1 and V _{F2 of} the intake fan F1 and the exhaust fan F2 corresponding to each detected temperature T are set so that the amount of air discharged per unit time substantially matches.
Further, the set temperature T ₀ in FIG. 3 is a value corresponding to the maximum value of the temperature inside the housing that does not hinder the housing 1 and internal electrical components without cooling the mother board 6 and the like. If the detected temperature T detected by the temperature sensor S2 is the set temperature T ₀ or less, the cooling is not required of the electrical components such as the motherboard 6, intake fan F1, exhaust fan F2 is not driven.
The allowable wind speed value ΔV is a value used as a comparison value when determining whether or not the dust filter 3 is clogged, and the wind speed V detected by the sensor S1 is continuously the allowable value ΔV. The occurrence of clogging in the dustproof filter 3 is detected at a time exceeding If the rotational speeds V _F1 and V _{F2 of the} intake fan F1 and the exhaust fan F2 are increased, a momentary deviation may occur between the intake amount of external air and the discharge amount of air due to uneven rotational speed caused by disturbances or the like. Therefore, the allowable value ΔV is set so as to increase as the rotational speeds V _F1 and V _F2 of the intake fan F1 and the exhaust fan F2 increase.
3 including these pieces of information is stored in advance in the ROM 8 as a function or as map-like data.

  In this embodiment, the wind speed V of the outside air flowing in through the air inlet 5 is used as a value indicating the inflow state of the outside air, but it is also possible to capture the inflow state of the outside air by the air volume or the wind pressure. Therefore, instead of the sensor S1 for detecting the wind speed, a sensor (air volume sensor, wind pressure sensor, etc.) for detecting the air volume or the wind pressure may be diverted.

In the above configuration, the main parts of the air circulation device of this embodiment are the intake fan F1, the air intake port 2, the dust filter 3, the air discharge port 4, the exhaust fan F2, the air intake port 5, and the inflow state of the outside air. It is formed by a sensor S1 for detecting.
Further, a control unit that compares the wind speed V detected by the sensor S1 with a preset allowable value ΔV and detects the occurrence of clogging in the dust filter 3 when the wind speed V continuously exceeds the allowable value ΔV. Is constituted by the CPU 7 of the mother board 6 built in the housing 1, and the monitor 13 provided in the housing 1 displays an occurrence of clogging of the dustproof filter 3 in response to an instruction from the CPU 7 which is a control unit. Functions as a display unit.
A combination of the CPU 7 functioning as a control unit, the monitor 13 functioning as an abnormality display unit, and the main components described above is an air circulation device in this embodiment. This air circulation device is mounted on the computer casing 1. Yes.

  FIG. 4 is a flowchart showing an outline of the clogging detection process repeatedly executed at predetermined intervals by the CPU 7 functioning as the control unit of the air circulation device. This process is executed as a background process of the CPU 7, and consideration is given not to prevent execution of other application programs.

  Next, with reference to FIG. 4, the operation of the air circulation device of this embodiment will be specifically described.

In the clogging detection process that is repeatedly executed at predetermined intervals, the CPU 7 that functions as the control unit of the air circulation device first reads the detected temperature T detected by the temperature sensor S2 (step a1), and this value is set. It determines whether or not reached a temperature T _0, that is, the intake fan F1, whether it is necessary to cool the electric components such as the motherboard 6 by driving the exhaust fan F2 (step a2).
If the judgment result of the detected temperature T is the step does not reach the set temperature T ₀ a2 is No, intake fan F1, there is no need to cool the electric components such as the motherboard 6 by driving the exhaust fan F2 . In addition, when the intake fan F1 and the exhaust fan F2 are not driven, the air pressure in the housing 1 matches the external air pressure regardless of whether the dust filter 3 is clogged. Since the detection of the clogging of the filter 3 becomes impossible, the CPU 7 ends the clogging detection process in this cycle as it is.

On the other hand, when the result of judgment in step a2 exceeds the detected temperature T is the set temperature T ₀ is Yes, it is necessary to cool the intake fan F1, the electrical components such as the motherboard 6 by driving the exhaust fan F2 Therefore, the CPU 7 obtains the rotational speeds V _F1 and V _F2 corresponding to the detected temperature T according to the function or map data stored in the ROM 8 (see FIG. 3), and the rotational speeds V _F1 and V _F2. In order to achieve this, the motors M1 and M2 are controlled, and the intake fan F1 and the exhaust fan F2 are driven at the rotational speeds V _F1 and V _F2 to circulate outside air inside the housing 1 (step a3).

  Next, the CPU 7 obtains the allowable value ΔV of the wind speed corresponding to the detected temperature T in accordance with the function or map data stored in the ROM 8 (see step a4 and FIG. 3), and is detected by the sensor S1 at the present time. The wind speed V is read (step a5), and whether or not this value has reached the allowable value ΔV, in other words, is there a possibility that the amount of outside air taken in by the intake fan F1 may be limited by clogging of the dustproof filter 3? It is determined whether or not (step a6).

As described above, in this embodiment, when the dust filter 3 is not clogged, the intake air amount per unit time by the intake fan F1 and the air discharge amount per unit time by the exhaust fan F2 are substantially the same. Since the intake fan F1 and exhaust fan F2 diameters and rotational speeds V _F1 and V _F2 are set so that the air pressure inside the housing 1 and the outside air pressure are substantially equal when the dustproof filter 3 is not clogged. To do. In this case, since the outside air does not flow into the housing 1 through the air suction port 5, the determination result at step a6 is false.

  Here, when the determination result of step a6 is false, that is, when the wind speed V of the outside air flowing into the housing 1 through the air inlet 5 has not reached the allowable value ΔV, it is practical. Since it is clear that the clogging which becomes a problem does not occur in the dustproof filter 3, the CPU 7 keeps the reset state of the abnormality detection flag f set to the reset state at the time of shipment from the factory or performs the previous processing. The abnormality detection flag f once set in the cycle is reset again (step a7), and the clogging detection process in this cycle is finished as it is.

On the other hand, in a state where the dust filter 3 is clogged, an increase in air resistance in the dust filter 3 restricts the intake amount of outside air per unit time in the intake fan F1, while air in the exhaust fan F2 is reduced. Since the discharge amount is not subject to any restriction, the air pressure in the housing 1 is relatively reduced compared to the external air pressure to become a negative pressure. In order to compensate for this atmospheric pressure difference, the air inlet 5 of the housing 1 is opened. Then, the outside air flows into the housing 1 and the inflow speed of the outside air at this time, that is, the wind speed V is detected by the sensor S1. When this clogging reaches a certain limit, the wind speed V of the outside air flowing into the housing 1 through the air inlet 5 exceeds the allowable value ΔV, and the determination result in step a6 becomes true.
However, due to an instantaneous rotation abnormality of the intake fan F1 or the exhaust fan F2, for example, a temporary decrease in the rotation speed of the intake fan F1, a temporary increase in the rotation speed of the exhaust fan F2, or a combination of these phenomena Since the air pressure in the housing 1 may temporarily decrease, it is not always appropriate to immediately determine that clogging has occurred when the wind speed V exceeds the allowable value ΔV.

  Therefore, if the determination result in step a6 is true and it is confirmed that the wind speed V of the outside air flowing into the housing 1 through the air inlet 5 exceeds the allowable value ΔV, the CPU 7 Is executed to identify whether the dust-proof filter 3 is clogged or due to a momentary rotation abnormality of the intake fan F1 or the exhaust fan F2.

  In this case, the CPU 7 first determines whether or not the abnormality detection flag f has already been set at this time, that is, whether or not the determination result of step a6 at least in the previous processing cycle is true (step a8).

  Here, if the determination result in step a8 is false and it is confirmed that the abnormality detection flag f is not set, at least in the previous processing cycle, the air enters the housing 1 via the air suction port 5. This means that the phenomenon in which the wind speed V of the inflowing outside air does not exceed the allowable value ΔV has occurred, and therefore the CPU 7 sets the initial value 1 again in the counter C for counting the number of times this phenomenon has occurred continuously (step a9) The abnormality detection flag f is set and a new occurrence of the phenomenon is stored (step a10), and the clogging detection process in this cycle is terminated. That is, the clogging of the dustproof filter 3 is not detected immediately when the wind speed V of the outside air flowing in through the air inlet 5 exceeds the allowable value ΔV.

  On the other hand, if the determination result in step a8 is true and it is confirmed that the abnormality detection flag f is set, the wind speed V of the outside air flowing into the housing 1 through the air inlet 5 is an allowable value. Since it means that a phenomenon exceeding ΔV has continuously occurred at least from the previous processing cycle, the CPU 7 increments the value of the counter C by 1, and updates and stores the number of times this phenomenon has occurred continuously (step). a11).

Next, the CPU 7 determines whether or not the current value of the counter C has reached a preset determination value N, that is, a phenomenon in which the wind speed V of the outside air flowing in from the air intake port 5 exceeds the allowable value ΔV. It is determined whether it is caused by a momentary rotation abnormality of the exhaust fan F2 or caused by clogging of the dust filter 3 (step a12).
Note that the determination value N is a determination value for identifying the cause of the wind velocity V of the outside air flowing from the air inlet 5 exceeding the allowable value ΔV, and an appropriate value is obtained in advance by experiments or the like. .

  Here, when the determination result of step a12 is false, that is, when the current value of the counter C has not reached the determination value N, the above phenomenon causes the instantaneous rotation of the intake fan F1 or the exhaust fan F2. Since there is a possibility that it has occurred due to an abnormality, the CPU 7 holds the set state of the abnormality detection flag f and the current value of the counter C, and ends the clogging detection process of the cycle as it is.

  On the other hand, when the determination result in step a12 is true and it is confirmed that the current value of the counter C has reached the determination value N, the phenomenon that the wind speed V of the outside air flowing in exceeds the allowable value ΔV occurs N times. That is, it is detected continuously over the processing cycle. In this case, not the instantaneous rotation abnormality of the intake fan F1 or the exhaust fan F2, but the intake amount of outside air is limited by the steady clogging of the dust filter 3, and the atmospheric pressure in the housing 1 is reduced. Therefore, the CPU 7 detects the occurrence of clogging in the dustproof filter 3 at this time, and displays a warning message indicating the occurrence of clogging on the display screen of the monitor 13 functioning as an abnormality display unit ( Step a13).

  In the above process, when a phenomenon is detected in which the wind speed V of the outside air flowing into the housing 1 is within the allowable value ΔV while the value of the counter C is 1 ≦ C <N. It is considered that the dust filter 3 itself is not clogged, and the abnormality detection flag f is reset in the process of step a7. In this case, when a phenomenon in which the wind speed V of the outside air exceeds the allowable value ΔV is detected in the processing cycle after the next cycle, the abnormality detection flag f is set in the processing of step a10 and the counter C performs the processing of step a9 Then, counting from the initial value 1 is started again. That is, the warning message indicating the occurrence of clogging is displayed on the monitor 13 functioning as an abnormality display unit because the phenomenon in which the wind speed V of the outside air exceeds the allowable value ΔV continues for N or more processing cycles. Further, this is only the case where the detection is continuously performed, and thus it is possible to reliably prevent abnormality display due to instantaneous rotation abnormality of the intake fan F1 and the exhaust fan F2.

The intake fan F1, exhaust fan F2 activation by the motor from the process after step a3 if the internal detection temperature T is sufficiently cooled is below the set temperature T ₀ of the casing 1 is skipped CPU 7 M1 , M2 is stopped, and as a result, the operation of the intake fan F1 and the exhaust fan F2 is also stopped. However, the values of the abnormality detection flag f and the counter C are held unless the CPU 7 is restarted. If the phenomenon that the outside air wind velocity V exceeds the allowable value ΔV is detected again when the detected temperature T rises again and the intake fan F1 and the exhaust fan F2 are started again, the counter C is in terms of the principle of operation. Ignoring the processing cycle in which the clogging of the dust-proof filter 3 has been disabled, that is, the processing cycle in which the intake fan F1 and the exhaust fan F2 have been stopped, is dust-proof from the point of operation principle. The end of the treatment period the detection of clogging was possible filter 3, i.e., will continue to count subsequently from the intake fan F1, processing cycle immediately before stopping the operation of the exhaust fan F2. Therefore, even if the intake fan F1 and the exhaust fan F2 are frequently turned on / off due to a temperature change in the housing 1, the time required for determination necessary for detecting the clogging of the dustproof filter 3 is excessive. There is no worry of being redundant.

  Since the warning message is displayed by the CPU 7 outputting a display signal to the monitor 13, even if this message is displayed once, the value of the abnormality detection flag f or the counter C is detected by restarting the CPU 7. However, in the situation where the dust filter 3 is clogged, the determination result in step a12 is always true when a certain amount of time has elapsed after the CPU 7 is started up. The display of the warning message can be held over the period from the start of the operation of the CPU 7 to the end of the operation.

  Further, when the clogging is eliminated by cleaning or replacing the dustproof filter 3, the determination result in step a6 is false. At this time, a special process such as clearing the display of the warning message is not performed. However, as described above, the display of the warning message is automatically cleared by restarting the CPU 7, and thereafter the dustproof filter 3 is clogged again. Until the warning message is not displayed.

  Next, the structural features of the air circulation device of this embodiment will be listed.

  First, in a state in which the dustproof filter 3 is not clogged, the amount of outside air taken into the housing 1 by the intake fan F1 and the integrated amount of air discharged to the outside by the exhaust fan F2 coincide with each other in the housing 1 Is equal to the outside air pressure, so that outside air does not flow into the housing 1 through the air inlet 5 of the housing 1. Therefore, the sensor S1 provided in the air inlet 5 of the housing 1 is not exposed to the air flow through the air inlet 5, and the sensor S1 is, as shown in FIG. 1, the intake fan F1. Since it is installed at a position away from both the exhaust fan F2 and the exhaust fan F2, it directly affects the flow of outside air sucked into the housing 1 by the intake fan F1 and the flow of air discharged from the housing 1 by the exhaust fan F2. It is not exposed to. Therefore, there are no problems such as adhesion of dirt to the sensor S1 and deterioration in detection accuracy of the wind speed of the sensor S1 due to dirt. At the same time, since the outside air sucked into the housing 1 for cooling is only clean air that has passed through the dustproof filter 3, it deteriorates to the electrical components inside the housing 1, such as the CPU 7, ROM 8, and RAM 9. And the problem of causing damage is also eliminated, and it is suitable as a cooling means for a computer casing or the like.

  When the dust filter 3 is clogged, the air resistance of the dust filter 3 increases, the amount of outside air taken into the housing 1 per unit time by the intake fan F1 is reduced, and the atmospheric pressure in the housing 1 is reduced. The state of the outside air flowing into the housing 1 through the air suction port 5 of the housing 1 in order to compensate for this pressure difference, specifically, the outside air flowing into the housing 1 from the air suction port 5 Is detected by the sensor S1, and the CPU 7 constituting the control unit detects the occurrence of clogging in the dust filter 3 when the wind speed V exceeds the allowable value ΔV. Thus, the dust-proofing is based on the fact that the air pressure in the housing 1 that has been kept dynamically equal to the external air pressure is lowered by the cooperative operation of the intake fan F1 and the exhaust fan F2, and the external air flows from the air intake port 5. Since clogging of the filter 3 is detected, even if the dustproof filter 3 is lightly clogged, it can be detected early. As a result, the dustproof filter 3 can be cleaned and replaced before the air resistance increases significantly due to the progress of clogging, and problems such as overloading of the motors M1 and M2 that drive the intake fan F1 and the exhaust fan F2 occur. Therefore, a small motor can be used as a drive source for the intake fan F1 and the exhaust fan F2, and the casing of precision equipment such as computers, especially laptop computers and notebook computers. It is also suitable as a cooling means.

  Moreover, when the outside air inflow velocity V detected by the sensor S1 continuously exceeds a preset allowable value ΔV, specifically, N times (set value) that are repeatedly executed at predetermined intervals. In the clogging detection process, the occurrence of clogging is detected only when a phenomenon occurs in which the outside air inflow velocity V exceeds the allowable value ΔV continuously. Therefore, the intake fan F1 and the exhaust fan F2 It can be reliably prevented that a drop in atmospheric pressure in the housing 1 due to an instantaneous rotation abnormality is erroneously detected as clogging of the dustproof filter 3.

  Further, the allowable value ΔV to be compared with the outside air inflow velocity V detected by the sensor S1 is a set value, and by adjusting the magnitude of this value, a criterion for determining that clogging has occurred is arbitrary. For example, when it is desired to circulate clean outside air in the housing, the allowable value ΔV is set to a low value to perform early maintenance of the dustproof filter 3, while giving priority to running cost. In addition, it is possible to selectively use the dust filter 3 to the limit of performance by setting the allowable value ΔV to a high value.

  As shown in FIG. 1, the air inlet 5 where the sensor S1 is installed has a surface orthogonal to the surface where the air intake 2 is provided, for example, one side surface 1c, 1d in FIG. Since the intake air is provided on the same surface as the side surface 1a of the housing 1 provided with the air intake port 2 and the intake fan F1, avoiding a surface that is likely to flow in a laminar flow along the wall. Reasons other than clogging of the dust filter 3, that is, the possibility that outside air is sucked from the air inlet 5 due to the air flow in the housing 1 can be reduced. In the case where it is necessary to circulate, the dust filter 3 is clogged by eliminating the influence of disturbance (a phenomenon in which outside air is sucked from the air inlet 5 due to the air flowing along the wall in the housing 1). It can be accurately detected. At the same time, since the possibility that the sensor S1 is exposed to the air flow in the housing 1 can be kept low, there is a merit that the initial accuracy of the sensor S1 can be stably maintained over a long period of time.

  Further, the microprocessor 7 on the mother board 6 is used as a control unit of the air circulation device, and the monitor 13 of the computer casing 1 is used as an abnormality display unit of the air circulation device. It is not necessary to separately provide the control unit and the abnormality display unit again, and the manufacturing cost of the entire apparatus can be reduced.

In this embodiment, the control unit for detecting the occurrence of clogging in the dust filter 3 is configured by the CPU 7 included in the motherboard 6 built in the housing 1, but the air circulation device is installed in the housing that does not incorporate the microprocessor. In the case of deployment, for example, the control unit of the air circulation device is configured by a comparator that compares the analog signal voltage from the sensor S1 and the reference voltage, and the comparator when the analog signal voltage from the sensor S1 exceeds the reference voltage. It is possible to configure the abnormality display unit by an LED or the like that is turned on based on a signal output from.
Also in this case, by providing a timer or the like, it is possible to prevent an abnormal display due to an instantaneous rotation abnormality of the intake fan F1 or the exhaust fan F2 in the same manner as described above. Specifically, the timer in this case is a timer that measures the duration of the signal output from the comparator when the analog signal voltage from the sensor S1 exceeds the reference voltage, and the measurement time of this timer is a set value. When the value exceeds, an abnormality display unit such as an LED is activated.

  Furthermore, it is possible to realize the method for detecting clogging of the dustproof filter according to the present invention with a simpler configuration.

For example, even if the sensor S1 shown in FIG. 1 is not provided, it is possible to implement a clogging detection device to which the operation principle of the clogging detection method of the present invention is applied. Specifically, the sensor S1 is removed from the housing 1 of FIG. 1, and the air suction port 5 is superposed on the outer side surface 1a of the housing 1 so as to have appropriate elasticity and toughness. It is possible to attach one end of an easy tongue piece and to easily detect the clogging of the dustproof filter 3 by causing the tongue piece to act like a valve. In this case, when the flow rate of the outside air sucked into the housing 1 from the air suction port 5 exceeds a certain limit, the tongue having a valve function comes into close contact with the outside of the side surface 1a of the housing 1, and the flow rate of the outside air Is less than a certain limit, the tongue having a valve function is separated from the outside of the one side surface 1a of the housing 1, so that the dust filter 3 is clogged by checking the state of the tongue. You can know the presence or absence.
When such a configuration is applied, the tongue piece substantially functions as a sensor and an abnormality display unit, so that the structure of the device is greatly simplified both in terms of hardware and software. It can be easily used for detecting clogging of a dustproof filter such as an air purifier having a simple structure without a monitor.
Further, as a configuration for realizing the sensor function and the abnormality display function at the same time, for example, instead of the above-mentioned tongue piece, a transparent tube connected to the air suction port 5 and extending downward is provided along this transparent tube. It is also possible to use a sphere or the like that is movably fitted up and down. In this case, if the inside of the housing 1 has a negative pressure, the sphere is sucked upward and moves, so that the presence or absence of clogging of the dustproof filter 3 can be easily confirmed.

  The present invention can be applied to detection of clogging of a dustproof filter provided in a housing of various devices having a dustproof structure.

It is the plane sectional view simplified and showed about one embodiment at the time of applying the clogging detection method and air circulation device of the present invention to the case for computers. It is the functional block diagram which simplified and showed the structure of the motherboard etc. provided with the microprocessor which functions as a control part of an air circulation apparatus. It is the diagram which showed the relationship between detected temperature T, rotational speed _VF1 , _VF2, and permissible value (DELTA) V of an intake / exhaust fan. It is the flowchart which showed the outline of the clogging detection process which the microprocessor which functions as a control part of an air circulation apparatus performs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Computer housing | casing 1a One side 1b of housing | casing The other one side 2 of a housing | casing 2 Air intake port 3 Dust-proof filter 4 Air exhaust port 5 Air inlet port 6 Mother board (electric part in a housing | casing)
7 Microprocessor (control unit of air circulation device)
8 ROM
9 RAM
10 Interface 11 Input / output circuit 12 Hard disk drive 13 Monitor (abnormality display)
14 Keyboard 15, 16 Driver 17, 18 A / D converter F 1 Intake fan F 2 Exhaust fan S 1 Sensor (wind speed sensor) that detects inflow of outside air
S2 Temperature sensor M1, M2 Motor T Detected temperature T ₀ Set temperature (maximum temperature in the housing that does not interfere with the housing and internal electrical components)
ΔV Allowable value V Wind speed (outflow state of outside air detected by sensor)

Claims (7)

An air circulation device comprising an intake fan that sucks outside air into the housing, a dust filter provided at an air intake port of the intake fan, and an air discharge port that discharges air inside the housing to the outside,
An exhaust fan for exhausting the air in the housing to the outside is provided at the air exhaust port, and the air intake port is provided in the housing so as to be spaced apart from the installation position of the intake fan and the exhaust fan. Install a sensor to detect the inflow of outside air into the air inlet,
As the internal temperature of the housing rises, the amount of air transported by the intake fan and the exhaust fan both increases, and the outside air per unit time by the intake fan is not clogged in the dustproof filter. Storage means for storing in advance the air conveyance amount of the intake fan and the exhaust fan so that the intake amount and the amount of air discharged per unit time by the exhaust fan coincide with each other ;
Drive control of the intake fan and the exhaust fan is performed based on the relationship between the air conveyance amount of the intake fan and the exhaust fan stored in the storage means and the internal temperature of the housing, and the current value of the internal temperature of the housing. And an allowable value corresponding to the current value of the internal temperature of the casing among the allowable values stored in advance in the storage unit corresponding to the internal temperature of the casing, and the inflow rate of the outside air detected by the sensor, And a control unit that detects occurrence of clogging in the dustproof filter when the inflow speed exceeds the allowable value . The air circulation device according to claim 1 , wherein the air suction port is provided on the same surface as the one surface of the housing provided with the air intake port. Wherein said control unit air circulation apparatus according to claim 1 or claim 2, wherein further comprising an abnormality display unit for displaying an abnormality when the occurrence of clogging is detected by.   A computer casing comprising the air circulation device according to any one of claims 1, 2, and 3. 4. A computer case comprising the air circulation device according to claim 3 , wherein the control unit is configured by a microprocessor of the computer case, and the abnormality display unit is configured by a monitor of the computer case. A computer case characterized by the above. 6. The computer according to claim 5 , wherein the control unit detects the occurrence of clogging when an outside air inflow velocity detected by the sensor exceeds the allowable value for a preset period. Enclosure. A clogging detection method for detecting clogging occurring in a dustproof filter disposed in an air intake port of a housing,
An intake fan that takes outside air into the casing through the dust filter and an exhaust fan provided at the air discharge port of the casing are used together, and the air conveyance amount of the intake fan and the exhaust fan is determined based on the internal temperature of the casing. As the air pressure in the housing is increased so that the air pressure in the housing is equal to the external air pressure in a state where the dust filter is not clogged, clean air is circulated in the housing.
An inflow rate of outside air from an air intake port provided in the housing apart from the positions where the intake fan and the exhaust fan are disposed, and an allowable value set corresponding to a current value of the internal temperature of the housing And detecting the occurrence of clogging when the inflow speed exceeds the allowable value, and detecting the clogging of the dustproof filter.

Images