Fluid delivery device

Abstract

The fluid transport device (10) is provided with a controller (50) that determines the clogging state of the structure (40) using a physical quantity relating to the pressure loss of the fluid passage (23) obtained from the motor (33). At least one of the conveying part (31) and the fluid passage (23) is configured so as to reduce the proportion of the disturbance to the physical quantity.

Description

Technical Field

[0001] The present disclosure relates to a fluid delivery device. Background Art

[0002] Patent Document 1 discloses a device that uses the stop time of a fan to determine the clogging state of a filter.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Publication No. 2002-102596 Summary of the invention

[0006] -Technical problem to be solved by the invention-

[0007] In a system that uses a physical quantity obtained from a motor to determine the clogging state of a structure such as a filter as disclosed in Patent Document 1, it is desired to improve the accuracy of determining the clogging state.

[0008] An object of the present disclosure is to provide a fluid transport device capable of improving the accuracy of determining a clogging state of a structure.

[0009] -Technical solutions for solving technical problems-

[0010] The first aspect relates to a fluid conveying device, which includes a fluid passage 23, a conveying part 31, a structure 40 and a controller 50, wherein the conveying part 31 has a motor 33 and an impeller 32 driven by the motor 33, the conveying part 31 conveys the fluid in the fluid passage 23, the structure 40 is arranged in the fluid passage 23, the controller 50 uses a physical quantity related to the pressure loss of the fluid passage 23 obtained from the motor 33 to determine the blockage state of the structure 40, and at least one of the conveying part 31 and the fluid passage 23 is configured to reduce the ratio of disturbance to the physical quantity.

[0011] In the first aspect, since the structure 40 is arranged in the fluid passage 23, when the structure 40 is blocked, the physical quantity related to the pressure loss of the fluid passage 23 also changes. Therefore, the blockage state of the structure 40 can be determined using the physical quantity. At least one of the conveying portion 31 and the fluid passage 23 is configured to reduce the ratio of the disturbance to the physical quantity obtained from the motor 33. Therefore, the determination accuracy of the blockage state of the structure 40 using the physical quantity can be improved.

[0012] The "reducing the ratio of the disturbance to the physical quantity" mentioned here includes the following 1) and 2).

[0013] 1) Reduce the proportion of disturbance relative to the physical quantity by reducing the disturbance.

[0014] 2) By increasing the amount of change in the physical quantity caused by the change in the pressure loss of the fluid passage 23 between the normal state and the blocked state of the structure, the ratio of the disturbance to the physical quantity is reduced.

[0015] In addition, the above 1) "reducing the ratio of disturbance to physical quantity by reducing disturbance" includes the following a) to c).

[0016] a) Reduce the influence of bearing loss of the conveying unit 31 on the physical quantity.

[0017] b) To reduce the influence of deformation of the impeller 32 caused by use on the physical quantity.

[0018] c) Reduce the impact of fluid movement from the outside to the inside of the fluid passage 23 on physical quantities

[0019] In a second aspect, based on the first aspect, the disturbance includes the influence of bearing loss of the conveying portion 31 .

[0020] If the bearing loss of the conveying unit 31 has a large influence, the disturbance to the physical quantity becomes large, resulting in a decrease in the accuracy of determining the clogging state of the structure 40. Therefore, in the second aspect, the influence of the bearing loss on the physical quantity is reduced.

[0021] According to a third aspect, based on the second aspect, at a rotation speed of 25% of the maximum rotation speed of the conveying unit 31 , a ratio of the output power of the conveying unit 31 to the sum of the output power and the bearing loss is greater than 90%.

[0022] The inventors of the present application have discovered that, at a rotation speed of 25% of the maximum rotation speed of the conveying unit 31, when the ratio of the output power of the conveying unit 31 to the sum of the output power and the bearing loss is low, the disturbance to the physical quantity obtained from the motor 33 becomes larger, resulting in a decrease in the accuracy of judging the blockage state of the structure 40.

[0023] In the third aspect, the conveying unit 31 is configured so that the ratio is greater than 90%. Therefore, the influence of the bearing loss of the conveying unit 31 on the physical quantity can be reduced, and the accuracy of determining the clogging state of the structure 40 can be improved.

[0024] According to a fourth aspect, in the first aspect, the disturbance includes an influence of deformation of the impeller 32 caused by use of the conveying unit 31 .

[0025] When impeller 32 is deformed as conveying unit 31 is used, disturbance of physical quantity increases, resulting in reduced accuracy in determining the clogging state of structure 40. Therefore, in the fourth aspect, the influence of deformation of impeller 32 on physical quantity is reduced.

[0026] According to a fifth aspect, based on the fourth aspect, the impeller 32 is made of resin.

[0027] If impeller 32 is made of resin, impeller 32 is easily deformed with use of conveying unit 31, resulting in reduced accuracy in determining the clogging state of structure 40. Therefore, in the fifth aspect, the influence of deformation of impeller 32 on physical quantity is reduced.

[0028] A sixth aspect is based on the fourth aspect or the fifth aspect, wherein the time when the first operation of the conveying unit 31 starts is set as time point ta, and the time when the motor 33 or the impeller 32 is operated at the maximum speed at the maximum use temperature for 600 hours from the time point ta is set as time point tb, and the conveying unit 31 is configured so that the change in the physical quantity caused by the deformation of the impeller 32 during the period from the time point ta to the time point tb is less than 50% of the required accuracy. Here, the "required accuracy" corresponds to the change in the physical quantity corresponding to the estimated error of the pressure loss of the fluid passage 23.

[0029] In the sixth aspect, the change in the physical quantity caused by the deformation of the impeller 32 during the period from time point t1 to time point t2 is less than half of the required accuracy, so the judgment accuracy of the structure 40 can be suppressed from being reduced due to the influence of the deformation of the impeller 32 on the physical quantity.

[0030] In a seventh aspect, based on the first aspect, the disturbance includes an effect of the fluid moving from outside to inside of the fluid passage 23 .

[0031] If the influence of the fluid moving from outside to inside the fluid passage 23 increases, the disturbance to the physical quantity increases, resulting in a decrease in the accuracy of determining the clogging state of the structure 40. Therefore, in the seventh aspect, the influence of the fluid moving from outside to inside the fluid passage 23 is reduced.

[0032] According to an eighth aspect, in the seventh aspect, at least one of the suction port (21) and the discharge port (22) of the fluid passage (23) is opened upward or downward.

[0033] In the eighth aspect, since the suction port 21 and / or the blowing port 22 are not open to the side, the fluid is unlikely to move from the outside to the inside of the fluid passage 23 due to the influence of, for example, lateral wind. Therefore, the influence of the fluid moving from the outside to the inside of the fluid passage 23 on the physical quantity can be reduced.

[0034] A ninth aspect is based on the seventh aspect or the eighth aspect, wherein at least one of the suction port (21) and the blowing port (22) of the fluid passage (23) is open toward the indoor space (I).

[0035] In the ninth aspect, since the suction port 21 and / or the blowing port 22 are not open to the outdoor space, it is difficult for the fluid to move from the outside to the inside of the fluid passage 23 due to the influence of, for example, lateral wind. Therefore, the influence of the movement of the fluid from the outside to the inside of the fluid passage 23 on the physical quantity can be reduced.

[0036] According to a tenth aspect, based on any one of the first to ninth aspects, the physical quantity is a degree of deceleration of the conveying unit 31 during a process in which the conveying unit 31 stops.

[0037] In the tenth aspect, the controller 50 determines the clogging state of the structure 40 using the degree of deceleration of the conveying unit 31 .

[0038] According to the eleventh aspect of the present invention, in the case where a deceleration time of the conveying unit 31 as the degree of deceleration is less than a predetermined value, the controller 50 determines that the structure 40 is in a clogged state.

[0039] In the eleventh aspect, when the deceleration time of the conveying unit 31 is shorter than a predetermined value, it is determined that the structure 40 is in a clogged state. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is an overall structural diagram of an oil cooling system involved in an embodiment;

[0041] Figure 2 is a three-dimensional diagram of the cooling device;

[0042] Figure 3 is a simplified structural diagram showing the internal structure of the cooling device;

[0043] Figure 4 is a block diagram of a cooling device;

[0044] Figure 5 It is a control flow chart for judging the blocking state;

[0045] Figure 6 is a graph showing the rotation speed characteristics of the fan during the stop period;

[0046] Figure 7 is a graph showing the result of evaluating the relationship between the ratio of the rotation speed of the fan to its maximum rotation speed and the ratio of the output power to the sum of the output power and the bearing loss;

[0047] Figure 8is a graph showing the rotation speed characteristics of a fan having a relatively large output power ratio during a stop period;

[0048] Fig. 9 is a graph showing the rotation speed characteristics of a fan having a relatively small output power ratio during a stop period;

[0049] Fig.10 is a schematic structural diagram showing the internal structure of the fluid delivery device of Modification 2A;

[0050] Fig.11 is a schematic structural diagram showing the internal structure of the fluid delivery device of Modification 2B;

[0051] Fig.12 This is a diagram for explaining the formula (2) of the third modification. DETAILED DESCRIPTION

[0052] The following is a detailed description of the embodiments of the present disclosure with reference to the accompanying drawings. It should be noted that the present disclosure is not limited to the embodiments shown below, and various changes can be made without departing from the technical concept of the present disclosure. The drawings are used to conceptually illustrate the present disclosure, so in order to facilitate understanding, the size, ratio or quantity is sometimes exaggerated or simplified as needed.

[0053] (1) Oil cooling system

[0054] Figure 1 The oil cooling system 1 shown is a system for cooling the oil of the machine tool 3. The oil cooling system 1 has a cooling device 10 and a circulation loop 2. The cooling device 10 cools the oil. The oil includes working oil, lubricating oil and cooling oil of the machine tool 3. The machine tool 3 includes a machining center, an NC (Numerical Control) lathe, a grinder, an NC dedicated machine tool, an NC electrical discharge machining machine, etc. The cooling device 10 can also cool the oil of a molding machine, a stamping machine, etc., which are different from the machine tool 3.

[0055] The oil tank 4, the pump 5, the evaporator 15, and the machine tool 3 are connected to the circulation loop 2. The oil tank 4 stores oil. The pump 5 delivers the oil in the circulation loop 2. The evaporator 15 is provided in the cooling device 10 to cool the oil in the circulation loop 2. The oil cooled in the evaporator 15 is supplied to the machine tool 3.

[0056] (2) Cooling device

[0057] The cooling device 10 is an example of a fluid delivery device of the present disclosure. Figure 1 As shown, the cooling device 10 has a refrigerant circuit 11. The cooling device 10 has a housing 20, a fan 31, a filter 40, and a controller 50.

[0058] (2-1) Refrigerant circuit

[0059] The refrigerant circuit 11 performs a refrigeration cycle by circulating a refrigerant filled therein. The refrigerant circuit 11 includes a compressor 12, a condenser 13, an expansion valve 14, and an evaporator 15. The compressor 12, the condenser 13, the expansion valve 14, and the evaporator 15 are connected to the refrigerant circuit 11 in this order.

[0060] The compressor 12 compresses the refrigerant. The condenser 13 is an air heat exchanger that exchanges heat between air and refrigerant. The condenser 13 is a fin-tube heat exchanger. The condenser 13 has a plurality of plate-shaped fins arranged in the plate thickness direction and a heat transfer tube that passes through these fins. A ventilation path for air is formed in the condenser 13. The expansion valve 14 is composed of, for example, an electronic expansion valve. The evaporator 15 exchanges heat between the refrigerant in the refrigerant circuit 11 and the oil in the circulation circuit 2. The evaporator 15 uses the refrigerant in the refrigerant circuit 11 to cool the oil in the circulation circuit 2. The refrigerant circuit 11 may also have a four-way reversing valve for switching between a forward cycle and a reverse cycle.

[0061] (2-2) Shell

[0062] like Figure 2 As shown in FIG. 1 , the housing 20 is formed in a hollow box shape. The housing 20 contains the compressor 12, the condenser 13, the expansion valve 14, the evaporator 15, the fan 31, and the filter 40. Figure 2 and Figure 3 As shown, an inlet 21 and an outlet 22 are formed on the housing 20. In the present embodiment, the inlet 21 is formed on the side of the housing 20, and the outlet 22 is formed on the upper surface of the housing 20. The inlet 21 is open to the side, and the outlet 22 is open to the top. An air passage 23 is formed inside the housing 20 from the inlet 21 to the outlet 22. The air passage 23 is an example of a fluid passage for the flow of air as a fluid. When viewed in longitudinal section, the air passage 23 is formed in a substantially L-shape.

[0063] In the air passage 23 , the filter 40 , the condenser 13 , and the fan 31 are arranged in this order from the upstream side toward the downstream side in the air flow direction.

[0064] (2-3) Fan

[0065] The fan 31 is an example of a conveying unit for conveying a fluid. The fan 31 conveys air in the air passage 23. The fan 31 is composed of a propeller fan. The fan 31 has an impeller 32 and a motor 33 for driving the impeller 32. The impeller 32 has a plurality of blades and a hub to which these blades are fixed. The impeller 32 and the motor 33 are connected by a drive shaft 34. The drive shaft 34 is supported by a bearing and can rotate.

[0066] (2-4) Filter

[0067] The filter 40 captures the object in the fluid. The object includes particulate matter such as oil mist and dust. The filter 40 is made of, for example, non-woven fabric and captures the object in a physical manner. The filter 40 is formed on the entire area of ​​the suction port 21 to cover the suction port 21. A ventilation path for air is formed in the filter 40. The filter 40 is an example of a structure that becomes an object of judgment of a clogging state. The above-mentioned condenser 13 is arranged on the back side of the filter 40.

[0068] (2-5) Controller

[0069] like Figure 4 As shown, the cooling device 10 includes a controller 50. The controller 50 includes a microcomputer mounted on a control substrate and a storage device (specifically, a semiconductor memory) storing software for operating the microcomputer.

[0070] The controller 50 controls the refrigerant circuit 11. Specifically, the controller 50 controls the on / off of the compressor 12 and the rotation speed of the compressor 12. The controller 50 controls the on / off of the fan 31 and the rotation speed of the fan 31. The rotation speed of the fan 31 corresponds to the rotation speed of the motor 33.

[0071] The controller 50 includes a drive circuit 51 that drives the fan 31. The drive circuit 51 includes an inverter circuit that has a plurality of switching elements and supplies a drive current to the motor 33.

[0072] A signal from the motor 33 is input to the controller 50. The signal includes at least one of the current, voltage, power, torque, rotation speed, magnetic flux, and induced voltage of the motor 33.

[0073] The cooling device 10 includes a detector 52 for detecting these signals of the motor 33. The detector 53 may be incorporated in the controller 50 or may be a separate body from the controller 50. The detector 52 of the present embodiment detects the rotation speed of the fan 31.

[0074] The controller 50 determines the clogging state of the filter 40 using the physical quantity P obtained from the motor 33. The physical quantity P is an index related to the pressure loss of the air passage 23.

[0075] The “clogging state” refers to a state in which the normal function of the filter 40 is impaired due to excessive objects being captured on the filter 40 .

[0076] The physical quantity P of the present embodiment is the deceleration degree of the fan 31. Here, the "deceleration degree" is an index indicating the degree of deceleration of the fan 31 during the period from when the driving force of the running fan 31 disappears to when the fan 31 completely stops (hereinafter also referred to as the stop period). The controller 50 uses the deceleration time ΔT of the fan 31 as the deceleration degree. The "deceleration time" is the time from when the fan 31 reaches the second speed R2 from the first speed R1 during the stop period. The details of the judgment control of the clogging state of the filter 40 will be described later.

[0077] The controller 50 has an output unit 53. When the controller 50 determines that the filter 40 is in a clogged state, the output unit 53 outputs first information indicating that the filter 40 is in a clogged state. In other words, the output unit 53 is a notification unit that notifies that the filter 40 is in a clogged state. The output unit 53 outputs the first information to the outside of the cooling device 10 through sound, light, display, communication, or any combination thereof. As specific examples of the output unit 53, a speaker, an indicator light, a display, a communication device, or a combination thereof, etc. can be listed.

[0078] (3) Operation of the oil cooling system

[0079] The basic operation of the oil cooling system 1 is described. When the oil cooling system 1 is in operation, the controller 50 operates the compressor 12 and the fan 31 and adjusts the opening of the expansion valve 14. When the pump 5 is in operation, the oil in the oil tank 4 is sent to the evaporator 15 and cooled by the evaporator 15. The cooled oil is sent to the machine tool 3 and then returns to the oil tank 4.

[0080] In the refrigerant circuit 11, the refrigerant compressed by the compressor 12 flows through the condenser 13. In the condenser 13, the refrigerant releases heat to the air and condenses. The condensed refrigerant is decompressed in the expansion valve 14 and then flows through the evaporator 15. In the evaporator 15, the refrigerant absorbs heat from the oil and evaporates. The evaporated refrigerant is sucked into the compressor 12.

[0081] When the fan 31 is running, the air outside the housing 20 flows into the air passage 23 from the suction port 21. The air passes through the filter 40. The filter 40 captures oil mist and dust in the air. The air passing through the filter 40 flows through the condenser 13 and is heated. The air passing through the condenser 13 is blown upward to the outside of the housing 20 from the blowout port 22.

[0082] (4) Determination of filter clogging status

[0083] When the filter 40 becomes clogged, it is necessary to replace or maintain the filter 40. The cooling device 10 of this example is applied to the oil cooling system 1, and sometimes a lot of oil mist exists in the air sucked into the air passage 23. Therefore, in the cooling device 10, the filter 40 is easily clogged. Therefore, the determination of the clogged state of the filter 40 is particularly important in ensuring the reliability of the oil cooling system 1.

[0084] On the other hand, it is also possible to arrange a pressure sensor or an air volume sensor in the air passage 23 and use these sensors to directly determine the clogging state of the filter 40. However, since oil mist flows in the air passage 23, it is difficult to use these sensors. Therefore, the controller 50 of this embodiment uses the physical quantity P obtained from the motor 33 to determine the clogging state of the filter 40.

[0085] (4-1) Judgment Control

[0086] Reference Figure 5 and Figure 6 The control for determining the clogging state of the filter 40 will be described.

[0087] In step S11, when the stop command of the fan 31 is input to the controller 50, the process proceeds to step S12. In step S12, the controller 50 stops the supply of power to the fan 31. Specifically, the controller 50 stops the supply of the drive current from the drive circuit 51 to the motor 33.

[0088] Next, in step S13, the controller 50 measures the deceleration time ΔT. Specifically, Figure 6 As shown, the controller 50 obtains the deceleration time ΔT from a first time point t1 when the rotation speed of the fan 31 is the first rotation speed R1 to a second time point t2 when the rotation speed of the fan 31 reaches the second rotation speed R2.

[0089] In step S14, the controller 50 compares the deceleration time ΔT with the reference value. In step S14, when the deceleration time ΔT is less than the reference value, the process is transferred to step S15. In step S15, the controller 50 determines that the filter 40 is in a clogged state. In step S16, the output unit 53 outputs the first information to the outside of the cooling device 10. Thus, users, maintenance personnel, manufacturers, etc. can quickly grasp the fact that the filter 40 is in a clogged state.

[0090] (4-2) Relationship between deceleration degree and filter clogging

[0091] When the driving force of the fan 31 disappears and the fan 31 is in an idling state or a free rotation state, the fan 31 continues to rotate due to inertia. At this time, since a load torque is generated on the fan 31 and the motor 33, the rotation speed of the fan 31 and the motor 33 is reduced. The load torque T at this time can be expressed by the following formula (1).

[0092] T=(Ps+Pv)×Q / N……(1)

[0093] Ps: Static pressure [Pa]

[0094] Pv: Dynamic pressure [Pa]

[0095] Q: Air volume [m 3 / sec]

[0096] N: Fan speed [rpm]

[0097] When the filter 40 becomes clogged, the static pressure Ps increases, and the pressure loss of the air passage 23 increases. When using a fan 31 having such air volume and static pressure characteristics that the load torque increases with the increase in the pressure loss of the air passage 23, the deceleration degree of the fan 31 increases due to the increase in the load torque, and the deceleration time ΔT becomes shorter. A fan having such characteristics is, for example, an axial flow fan such as a propeller fan. Therefore, as described above, based on the fact that the deceleration time ΔT of the axial flow fan 31 becomes less than the reference value, it can be determined that the pressure loss of the air passage 23 increases, and further it can be determined that the filter 40 is in a clogged state.

[0098] (4-3) Regarding the First Rotation Speed ​​and the Second Rotation Speed

[0099] The maximum rotation speed (Rmax) of the fan 31 in the present embodiment is 1500 [rpm]. The first rotation speed R1 in the present embodiment is set to 1400 [rpm], and the second rotation speed R2 is set to 400 [rpm].

[0100] The first rotation speed R1 may be the maximum rotation speed Rmax. By making the first rotation speed R1 relatively large, the amount of change in the deceleration time ΔT between the normal state and the clogged state becomes large, thereby preventing misjudgment of the clogged state of the filter 40.

[0101] The second rotation speed R2 is preferably 25% or more of the maximum rotation speed Rmax of the fan 31. The bearing loss is proportional to the rotation speed of the fan 31, and the output power is proportional to the cube of the rotation speed of the fan 31. Therefore, when the rotation speed of the fan 31 decreases, the ratio of the output power to the sum of the bearing loss and the output power decreases sharply.

[0102] Figure 7: is a graph showing an example of the ratio of the rotation speed of the fan 31 to its maximum rotation speed Rmax and the ratio of the output power to the sum of the bearing loss and the output power. Figure 7 It can be seen that the point where the ratio of the output power decreases sharply is located near the rotation speed of 25% of the maximum rotation speed Rmax of the fan 31. When the second rotation speed R2 becomes smaller than 25% of the maximum rotation speed Rmax, the ratio of the output power to the sum of the bearing loss and the output power becomes smaller, and the possibility of misjudging the clogging state of the filter 40 becomes higher. By setting the second rotation speed R2 to more than 25% of the maximum rotation speed Rmax, the decrease in the accuracy of judging the clogging state can be suppressed. The detailed reason why the accuracy of judging the clogging state of the filter 40 decreases when the ratio of the output power decreases will be described later.

[0103] (5-1) Impact of bearing loss

[0104] When the clogging state of the filter 40 is determined using the physical quantity P obtained from the motor 33, the ratio of the disturbance to the physical quantity P increases due to the influence of the bearing loss of the fan 31, resulting in a decrease in the determination accuracy of the clogging state of the filter 40. This point will be described in detail.

[0105] The inventors of the present application have found that when the ratio of the output power of the fan 31 to the sum of the output power and the bearing loss is small, the ratio of the disturbance to the physical quantity P becomes large, resulting in a decrease in the accuracy of determining the clogging state.

[0106] Figure 8 This is a graph showing the rotation speed characteristics of fan 31 during a stop period, which has a configuration in which the ratio of the output power to the sum of the output power and the bearing loss is relatively large. Fig. 9 This is a graph showing the rotation speed characteristics of fan 31 during a stop period, which has a configuration in which the ratio of the output power to the sum of the output power and the bearing loss is relatively small. Figure 8 and Fig. 9 The solid line in represents the rotation speed characteristics when the filter 40 is in a normal state. Figure 8 and Fig. 9 The dotted line in represents the rotation speed characteristics when the filter 40 is in a clogged state. It should be noted that the "normal state" means that the filter 40 as a structural body is brand new and the function of the filter 40 is not damaged.

[0107] The output power is an indicator that affects the pressure loss of the air passage 23. In contrast, the bearing loss of the fan 31 is a mechanical loss caused by the friction of the bearing of the drive shaft 34 of the fan 31, and therefore can be considered as an indicator that does not affect the pressure loss of the air passage 23. Figure 8As shown, in the structure of the fan 31 with a large output power ratio, when the filter 40 changes from a normal state to a blocked state, the change ratio of the load torque including the bearing loss is relatively large. Figure 8 In the fan 31, the difference between the deceleration time ΔT when the filter 40 is in a normal state and the deceleration time ΔT when the filter 40 is in a blocked state is relatively large. Figure 8 As shown, the difference ΔT2 between the second time point t2 when the filter 40 is in the normal state and the second time point t2 ′ when the filter 40 is in the blocked state is also relatively large.

[0108] In contrast, Fig. 9 As shown, in the structure of the fan 31 with a relatively small output power ratio, even if the filter 40 changes from a normal state to a clogged state, the change ratio of the load torque including the bearing loss is relatively small. Fig. 9 In the fan 31, the difference between the deceleration time ΔT when the filter 40 is in a normal state and the deceleration time ΔT when the filter 40 is in a blocked state is relatively small. Fig. 9 In the fan 31, the difference ΔT2 between the second time point t2 when the filter 40 is in the normal state and the second time point t2' when the filter 40 is in the blocked state is relatively small.

[0109] like Fig. 9 As shown, when the difference in the deceleration time ΔT between the normal state and the blocked state of the filter 40 is small, the blocked state of the filter 40 may be misjudged. The physical quantity P obtained from the motor 33, namely the deceleration time ΔT, may be deviated due to other influences. The main causes of the deviation include: the influence of deformation of the fan 31 caused by use, the influence of air moving from the outside to the inside of the air passage 23, the influence of the density of the fluid flowing in the air passage 23, the influence of individual differences of the components of the fan 31, etc. If an error occurs in the deceleration time ΔT obtained from the motor 33 due to these influences, causing the deceleration time ΔT to become less than the reference value, even if the filter 40 is not in a blocked state, it will be misjudged that the filter 40 is in a blocked state.

[0110] (5-2) Fan structure for suppressing erroneous judgment

[0111] In order to solve the above-mentioned technical problems, the fan 31 of the present embodiment is constructed to reduce the ratio of disturbance to the physical quantity P. The disturbance mentioned here is the influence of the bearing loss of the fan 31. That is, the fan 31 is constructed to reduce the influence of the bearing loss on the physical quantity P. Specifically, the fan 31 is a structure having the following characteristics: the ratio of the output power of the fan 31 to the sum of the output power and the bearing loss is greater than a specified value. More specifically, the fan 31 is constructed so that at a rotation speed of 25% of the maximum rotation speed of the fan 31, the ratio of the output power of the fan 31 to the sum of the output power and the bearing loss is greater than 90%. Specifically, the structure, element components, shape, material, specifications, etc. of the fan 31 are determined to satisfy this relationship. For example, by using rolling bearings or magnetic bearings, the ratio of the output power of the fan 31 to the sum of the output power and the bearing loss can be increased.

[0112] As described above, the clogging state of the filter 40 is determined in the region where the rotation speed of the fan 31 is higher than 25% of the maximum rotation speed Rmax. Therefore, if the ratio of the output power is greater than 90% at a rotation speed of 25% of the maximum rotation speed Rmax of the fan 31, the ratio of the output power will also be greater than 90% in the region where the rotation speed is higher than that. This is because, as described above, the greater the rotation speed of the fan 31, the greater the ratio of the output power.

[0113] Here, the reason for setting the lower limit of the output power ratio to 90% is explained. The inventor of the present application used a general fan to verify the change in output power until the filter changes from a normal state to a blocked state. For a general fan when not in use, the output power is 30.6 [W] when the rotation speed is 1400 [rpm]. In contrast, when the filter becomes blocked, the output power increases to 31.0 [W]. That is, when the filter changes from a normal state to a blocked state, the increase in output power is 0.4 [W]. In contrast, if the increase rate of the bearing loss generated by the use of the fan is set to 5%, in order to meet the condition that the increase in output power is greater than the increase in bearing loss, the bearing loss of the fan when not in use needs to be less than about 8.5 [W]. In other words, in order to meet this condition, the output power ratio of the fan needs to be about 78% or more. Multiplying the output power ratio by a surplus rate of about 1.2, the lower limit of the output power ratio becomes 90%.

[0114] With this configuration of the fan 31 , the ratio of the output power during the period from the first rotation speed R1 to the second rotation speed R2 is 90% or more. As a result, the influence of the bearing loss on the deceleration time ΔT can be reduced, and the clogging state of the filter 40 can be accurately determined.

[0115] (5-3) Effects of Implementation Methods

[0116] As described above, the present embodiment includes the controller 50, which uses the deceleration time ΔT obtained from the motor 33 and related to the pressure loss of the air passage 23 to determine the clogging state of the filter 40, and the fan 31 is configured to reduce the ratio of the disturbance to the deceleration time ΔT. The disturbance mentioned here is the influence of the bearing loss of the fan 31.

[0117] This can suppress Fig. 9 As shown in the figure, the difference in deceleration time ΔT between the normal state and the clogged state of the filter 40 becomes small, and thus it is possible to suppress a decrease in the accuracy of determining the clogged state of the filter 40 due to this.

[0118] In particular, the fan 31 is configured such that the ratio of the output power of the fan 31 to the sum of the output power and the bearing loss is greater than 90% at a rotation speed of 25% of the maximum rotation speed Rmax of the fan 31. This configuration can increase the ratio of the output power in the rotation speed region in which the deceleration time of the fan 31 is measured, thereby effectively suppressing a decrease in the accuracy of determining the clogging state of the filter 40.

[0119] The controller 50 determines the clogging state of the filter 40 based on the rotation speed of the motor 33 detected by the detection unit 52. Here, the rotation speed of the motor 33 is also used for the rotation speed control of the motor 33. That is, the detection unit 52 is used for both the rotation speed control of the motor 33 and the determination of the clogging state of the filter 40. Therefore, the number of detection units can be reduced.

[0120] (6) Modification

[0121] The above-mentioned embodiment may also adopt the following modified examples. It should be noted that the structures of the following modified examples may be added to the above-mentioned embodiment, or may be applied by changing a part of the structure of the above-mentioned embodiment.

[0122] (6-1) Modification 1: Structure for reducing the influence of deformation of the impeller accompanying use

[0123] The influence of the deformation of the impeller 32 accompanying use becomes a disturbance to the physical quantity obtained from the motor 33. If the physical quantity changes due to the influence of the disturbance, the accuracy of judging the clogging state of the filter 40 will be reduced. Therefore, the fan 31 of the modification example 1 is configured to reduce the influence of the deformation of the impeller 32 accompanying use on the physical quantity P. The impeller 32 of the fan 31 is made of resin, and is configured so that the so-called aging deformation of the impeller 32 is small. It should be noted that the impeller 32 can also be made of a metal material that is not easily deformed by aging.

[0124] The time when the fan 31 starts to operate for the first time is set as time point ta, and the time when the above-mentioned motor 33 or impeller 32 operates at the maximum speed at the highest operating temperature for 600 hours from the time point ta is set as time point tb. The fan 31 is constructed so that the change in the physical quantity P caused by the deformation of the impeller 32 during the period from time point ta to time point tb is less than 50% of the required accuracy. Here, "required accuracy" is equivalent to the change in the physical quantity corresponding to the estimated error of the pressure loss of the fluid passage 23. The structure, element components, shape, material, specifications, etc. of the fan 31 are determined to satisfy this relationship. For example, by making the material of the fan PEEK (polyetheretherketone) with creep resistance, this relationship can be satisfied.

[0125] For example, when the allowable error of the estimated value of the pressure loss required for the product is 10pa±5pa, the change in the deceleration time ΔT corresponding to the allowable error (i.e., the required accuracy) is, for example, 63.5 [msec]. In this case, the fan 31 is configured so that the change in the deceleration time ΔT caused by the deformation of the impeller 32 during the period from the time point ta to the time point tb is less than 50% of 63.5 [msec]. As a result, the disturbance of the deceleration time ΔT caused by the deformation of the impeller 32 can be suppressed below the allowable error, thereby suppressing the reduction in the accuracy of the judgment of the clogging state of the filter 40.

[0126] It should be noted that the above-mentioned 600 hours is an effective value of the time required for the deformation of a general fan 31 to converge when it is used at the maximum rotation speed at the highest use temperature, and is a time obtained based on experience.

[0127] (6-2) Modification 2: Structure that reduces the influence of fluid moving from the outside to the inside of the fluid passage

[0128] The movement of the fluid from the outside to the inside of the air passage 23 will cause a disturbance to the physical quantity obtained from the motor 33. If this influence becomes larger, the accuracy of determining the clogging state of the filter 40 will decrease. Therefore, the air passage 23 of the second modification is configured to reduce the influence of the movement of the fluid from the outside to the inside of the air passage 23.

[0129] (6-2-1) Modification 2A:

[0130] Specifically, in variant 2A, if Fig.10 As shown, the air inlet 21 of the air passage 23 opens downward, and the air outlet 22 of the air passage 23 opens upward. With this structure, it is possible to suppress the air from moving from the outside to the inside of the air passage 23 due to the influence of the side wind. Therefore, it is possible to suppress the ratio of the disturbance to the physical quantity P from increasing due to the influence of the side wind, and thus it is possible to suppress the misjudgment of the clogging state of the filter 40.

[0131] It should be noted that, as in the above embodiment, the blowout port 22 may be opened upward and the suction port 21 may be opened laterally. In other words, any structure may be adopted as long as at least one of the suction port 21 and the blowout port 22 is opened upward or downward.

[0132] (6-2-2) Modification 2B:

[0133] Specifically, in variant 2B, if Fig.11 As shown, the cooling device 10 is installed in the indoor space I. The air inlet 21 and the air outlet 22 of the air passage 23 are open toward the indoor space I. With this structure, it is possible to suppress the air from moving from the outside to the inside of the air passage 23 due to the influence of the outdoor side wind. Therefore, it is possible to suppress the ratio of the disturbance to the physical quantity P from increasing due to the influence of the outdoor side wind, so it is possible to suppress the misjudgment of the clogging state of the filter 40.

[0134] It should be noted that one of the air inlet 21 and the air outlet 22 may be open to the indoor space I, and the other may be open to the outdoor space.

[0135] (6-3) Modification 3: Relationship of physical quantities between normal state and jammed state

[0136] The cooling device 10 of the modification 3 is configured to satisfy the relationship of the following formula (2).

[0137] X>Y+Y' / 2……(2)

[0138] Here, Y is the physical quantity P obtained from the motor 33 in the filter 40 in a normal state. Y' is the physical quantity P obtained from the motor 33 in the filter 40 in a clogged state. The physical quantity P is, for example, the deceleration time ΔT. As described above, deviations may occur in Y and Y' due to various reasons. The main causes of the deviations are, as described above, the influence of bearing loss, the influence of deformation of the fan 31 accompanying use, the influence of air moving from the outside to the inside of the air passage 23, the influence of the density of the fluid flowing in the air passage 23, the influence of individual differences in the components of the fan 31, etc. Therefore, as described above, Fig.12 As shown, Y and Y' have a predetermined range. X is the difference between the center value c1 of the range of Y and the center value c2 of the range of Y'.

[0139] One or both of the fan 31 and the air passage 23 are configured to satisfy the above formula (2). Specifically, the structure, shape, material, specifications, etc. of one or both of the fan 31 and the air passage 23 are determined by evaluating the above-mentioned multiple influences.

[0140] As indicators related to the density of the fluid flowing in the air passage 23, there are the temperature, humidity, pressure, contamination degree, etc. of the fluid. These indicators can be used to evaluate the influence of the density of the fluid. Individual differences in components can be evaluated by preparing a plurality of component samples and using their actual capability values.

[0141] if Fig.12 If Y and Y' shown in the figure overlap, in the above-mentioned judgment of the clogging state, it may happen that the filter 40 is in a normal state but is mistakenly judged to be in a clogging state. On the other hand, if the relationship of the above-mentioned formula (2) is satisfied, Y and Y' will not overlap. Therefore, it is possible to suppress the decrease in the judgment accuracy of the clogging state due to the above-mentioned various reasons.

[0142] (6-4) Modification 4: Correction of physical quantities

[0143] The controller 50 of the fourth modification corrects the physical quantity P obtained from the motor 33 using other physical quantities, and then judges the clogging state of the structure 40 using the corrected physical quantity as a judgment value.

[0144] (6-4-1) Modification 4A: Correction based on the amount of deformation of the fan caused by use

[0145] If the fan 31 is deformed as it is used, the physical quantity P obtained from the motor 33 changes as described above. Then, the controller 50 corrects the physical quantity P using the deformation amount of the fan 31 .

[0146] If the deformation of the fan 31 becomes larger, the deceleration time ΔT obtained from the motor 33 will become longer. Therefore, it may happen that although the filter 40 is in a blocked state, the relationship in the above step S14 does not hold and it is not judged as a blocked state. The controller 50 of the modified example 4A corrects the deceleration time ΔT to a smaller value as the deformation of the fan 31 increases. Thereby, it is possible to suppress the accuracy of the judgment of the blockage state from being reduced due to the deformation of the fan 31 caused by the use. It should be noted that the deformation of the fan 31 is estimated by the controller 50 based on the operating time of the fan 31, the rotation speed of the fan 31, the temperature of the fan 31 and the specifications of the fan 31. Alternatively, the deformation of the fan 31 is directly measured by a sensor.

[0147] (6-4-2) Modification 4B: Correction based on fluid density

[0148] If the density of the fluid in the air passage 23 changes, the physical quantity P obtained from the motor 33 will change. Therefore, the controller 50 uses an index related to the density of the fluid to correct the physical quantity P. As such an index, there are the temperature, humidity, pressure, contamination degree, etc. of the fluid. These indexes are directly measured by sensors arranged in the air passage 23. Alternatively, these indexes are determined by constants determined according to the physical property values ​​of the fluid and the altitude at which the cooling device 10 is used. In this way, it is possible to suppress the decrease in the accuracy of the judgment of the blockage state due to the change in the density of the fluid in the air passage 23.

[0149] (6-5) Modification 5: Structure for increasing the amount of change in physical quantity

[0150] The fan 31 of the modification example 5 is configured to reduce the ratio of the disturbance to the physical quantity P by increasing the change ΔP of the physical quantity P caused by the change of the pressure loss of the air passage 23 between the filter 40 being in the normal state and the filter 40 being in the blocked state. Specifically, the fan 31 increases the change ΔP by reducing the inertia (rotational inertia) of the fan 31. The impeller 32 of the modification example 5 is composed of a material with a lower density than a metal material, for example. Specifically, the impeller 32 is made of a resin material such as polypropylene.

[0151] While the fan 31 is stopped, the following equation of motion (3) holds true.

[0152] J×α=T……(3)

[0153] T: load torque

[0154] α: angular acceleration

[0155] J: Inertia

[0156] Here, α is equivalent to the deceleration of the fan 31 during the stop period of the fan 31. When the load torque of the fan 31 increases with the clogging of the filter 40, the smaller the inertia, the greater the deceleration (angular acceleration α) of the fan 31. Therefore, if the physical quantity P related to the pressure loss is set to the deceleration (angular acceleration α) of the fan 31, the deceleration of the fan 31 will increase by reducing the inertia of the fan 31, and the change amplitude of the physical quantity P related to the pressure loss will increase. That is, Modification 5 is configured to make the change of the physical quantity P in the clogging state obvious.

[0157] (7) Other Implementation Methods

[0158] In the above-described embodiment and each modified example, the following configuration may be adopted.

[0159] (7-1) Transport unit

[0160] The conveying unit conveys the fluid by rotational motion. The conveying unit may be not only a fan 31 for conveying gas such as air, but also a pump for conveying liquid such as water. In this case, the fluid passage constitutes a passage for the liquid to flow.

[0161] (7-2) Structure

[0162] The structure is arranged in the fluid passage, and air passing through the structure will generate pressure loss in the fluid passage. As long as it is such a structure, the structure may not be the filter 40. Specifically, the structure may also be a heat exchanger such as a condenser, an evaporator, or a radiator. The structure may also be a demister or an electrostatic precipitator.

[0163] (7-3) Physical quantities

[0164] The physical quantity P is an index related to the pressure loss of the fluid passage 23 obtained from the motor 33. The physical quantity P may be an index other than the deceleration time ΔT. As an index related to the degree of deceleration, the deceleration speed of the fan 31 during the stop period of the fan 31 may be used. As physical quantities P other than the degree of deceleration, there are the current, voltage, or power, torque, rotation speed, magnetic flux, induced voltage, sound, and vibration of the motor 33. The physical quantity P may also be a spectrum of the current, voltage, power, or torque of the motor 33.

[0165] When the blocking state is determined by using these physical quantities P, the determination accuracy is easily reduced due to the influence of the bearing loss as described above. Therefore, as in the above embodiment, by reducing the influence of the bearing loss, the determination accuracy can be improved. In particular, when the power of the motor 33 or the physical quantity P related to the power of the motor 33 such as the effective value of the current, the above deceleration time ΔT, etc. is used, the structure of the above embodiment is very effective.

[0166] When the power of the motor 33 is used as the physical quantity P, the storage unit of the controller 50 stores the rotation speed of the motor 33 when the structure 40 is in a normal state and the power value of the motor 33 corresponding to the rotation speed (reference power value). If the actual power value of the motor 33 is greater than the reference power value corresponding to the rotation speed by a specified value (for example, more than 5% of the reference power value) when the motor 33 is at a specified rotation speed, the controller 50 determines that the structure 40 is in a blocked state.

[0167] (7-4) Determination of deceleration time

[0168] According to the characteristics of the fan 31, when the deceleration time ΔT is greater than the reference value, the controller 50 may also determine that the structure 40 is in a blocked state. Specifically, like a sirocco fan, the fan 31 has a characteristic that its deceleration degree decreases due to an increase in the static pressure of the fluid passage 23. In this case, the deceleration time ΔT will be longer due to the blockage of the structure 40. Therefore, when the deceleration time ΔT is greater than the reference value, the controller 50 determines that the structure 40 is in a blocked state.

[0169] (7-5) Other application examples of fluid transport devices

[0170] The fluid conveying device can also be applied to an air handling device. The air handling device mentioned here is a device having an air passage 23 for air flow, including an air conditioning device, an air purifier, a humidity control device, a ventilation device, a hot water supply device, etc. The air conditioning device mentioned here also includes a device for cooling the interior of a cold storage, a freezer, etc. The air passage can also be the passage of an outdoor unit of an air conditioning device or a hot water supply device. The fluid conveying device can also be applied to a device including a flow path for liquid flow, such as a hydroelectric power generation device.

[0171] (7-6) Determination of blocking status

[0172] The controller 50 compares the physical quantity obtained from the motor 33 with a predetermined reference value to determine whether the filter 40 is clogged. However, the controller 50 may determine the degree of clogging of the filter 40 (the clogging development stage) based on the physical quantity obtained from the motor 33.

[0173] The above embodiments, variations and other embodiments are described, but it should be understood that various changes can be made to the form and specific circumstances without departing from the spirit and scope of the claims. In addition, the elements of the above embodiments, variations and other embodiments can also be appropriately combined or replaced.

[0174] The words "first", "second", "third", etc. mentioned above are only used to distinguish sentences containing the above words, and do not limit the number and order of the sentences.

[0175] - Industrial Applicability -

[0176] In summary, the present disclosure is useful for fluid delivery devices.

[0177] - Explanation of symbols -

[0178] 10 Cooling device (fluid conveying device)

[0179] 21 suction port

[0180] 22 Blowing outlet

[0181] 23 Air passage (fluid passage)

[0182] 31 Fan (conveying unit)

[0183] 32 Impeller

[0184] 33 Electric Motor

[0185] 40 filter(struct)

[0186] I. Interior Space

Claims

1. A fluid delivery device, characterized in that: The fluid conveying device comprises a fluid passage (23), a conveying portion (31), a structure (40) and a controller (50). The conveying section (31) has a motor (33) and an impeller (32) driven by the motor (33), and the conveying section (31) conveys the fluid in the fluid passage (23). The structure (40) is arranged in the fluid passage (23), The controller (50) determines the clogging state of the structure (40) using a physical quantity related to the pressure loss of the fluid passage (23) obtained from the motor (33). At least one of the transport portion (31) and the fluid passage (23) is configured to reduce a ratio of the disturbance to the physical quantity.

2. The fluid delivery device according to claim 1, characterized in that: The disturbance includes the influence of bearing losses of the conveying section (31).

3. The fluid delivery device according to claim 2, characterized in that: At a rotation speed of 25% of the maximum rotation speed of the conveying part (31), a ratio of the output power of the conveying part (31) to the sum of the output power and the bearing loss is greater than 90%.

4. The fluid delivery device according to claim 1, characterized in that: The disturbance includes the influence of deformation of the impeller (32) caused by the use of the conveying part (31).

5. The fluid delivery device according to claim 4, characterized in that: The impeller (32) is made of resin.

6. The fluid delivery device according to claim 4 or 5, characterized in that: The time when the conveying unit (31) starts to operate for the first time is defined as time point ta, and the time when the motor (33) or the impeller (32) operates at the maximum rotation speed at the maximum operating temperature for 600 hours from the time point ta is defined as time point tb, The conveying section (31) is configured so that a change in the physical quantity caused by deformation of the impeller (32) during a period from the time point ta to the time point tb is 50% or less of a required accuracy.

7. The fluid delivery device according to claim 1, characterized in that: The disturbance includes the effect of the fluid moving from the outside to the inside of the fluid passage (23).

8. The fluid delivery device according to claim 7, characterized in that: At least one of the suction port (21) and the blowing port (22) of the fluid passage (23) is open upward or downward.

9. The fluid delivery device according to claim 7 or 8, characterized in that: At least one of the suction port (21) and the blowing port (22) of the fluid passage (23) is open toward the indoor space (I).

10. The fluid delivery device according to any one of claims 1 to 9, characterized in that: The physical quantity is the degree of deceleration of the conveying unit (31) during the process of the conveying unit (31) stopping.

11. The fluid delivery device according to claim 10, characterized in that: When the deceleration time of the conveying unit (31) as the degree of deceleration is less than a predetermined value, the controller (50) determines that the structure (40) is in a blocked state.

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