Thermal flow velocity and flow rate sensor, and air conditioner

A thermal flow velocity and flow rate sensor includes: a substrate; a heater mounted on the substrate; a temperature measuring element mounted on the substrate; a joint portion made of a resin filled between the heater and the temperature measuring element and thermally connecting the heater and the temperature measuring element; a lead wire connected to the substrate; and a fastener fixing the lead wire to the substrate. The lead wire is soldered to the substrate. The lead wire and the fastener are coated with the resin.

TECHNICAL FIELD

The present disclosure relates to a thermal flow velocity and flow rate sensor, and an air conditioner including the sensor.

BACKGROUND

Flow velocity and flow rate sensors include a thermal flow velocity and flow rate sensor including a single substrate equipped with a heat generating element configured to generate heat in accordance with supply current, and a temperature measuring element configured to detect temperature of the heat generated from the heat generating element. The thermal flow velocity and flow rate sensor thus configured measures flow velocity and a flow rate with reference to temperature of heat detected by the temperature measuring element, on the basis of the fact that heat generated from the heat generating element changes in accordance with flow velocity (see PATENT LITERATURE 1 and the like). The heat generating element and the temperature measuring element each have an exposed surface in the thermal flow velocity and flow rate sensor, and heat is transmitted from the heat generating element to the temperature measuring element via air existing around the heat generating element and the temperature measuring element.

PATENT LITERATURE

Measurement accuracy of the thermal flow velocity and flow rate sensor is improved effectively by increase in heat transmission efficiency from the heat generating element to the temperature measuring element and a configuration enabling the temperature measuring element to detect heat generated at the heat generating element as quickly as possible. However, the heat generating element and the temperature measuring element interpose air therebetween in the thermal flow velocity and flow rate sensor. The heat transmission efficiency from the heat generating element to the temperature measuring element is principally determined in accordance with heat conductivity of air. It is accordingly difficult to increase heat transmission efficiency from the heat generating element to the temperature measuring element to improve measurement accuracy of the thermal flow velocity and flow rate sensor.

SUMMARY

One or more embodiments of the present disclosure provide a thermal flow velocity and flow rate sensor that can be improved in flow velocity and flow rate measurement accuracy, and an air conditioner including the thermal flow velocity and flow rate sensor.

A thermal flow velocity and flow rate sensor according to the present disclosure includes: a substrate; a heat generating element mounted on the substrate; a temperature measuring element mounted on the substrate; a joint portion made of a resin filled between the heat generating element and the temperature measuring element and thermally connecting the heat generating element and the temperature measuring element; a lead wire connected to the substrate; and a fixing member fixing the lead wire to the substrate, wherein the lead wire is soldered to the substrate, and the lead wire and the fixing member are coated with the resin.

DETAILED DESCRIPTION

Embodiments will be described hereinafter.

[Entire Configuration of Flow Velocity and Flow Rate Sensor]

FIG.1depicts a flow velocity and flow rate sensor1corresponding to a thermal flow velocity and flow rate sensor according to one or more embodiments of the present disclosure. The flow velocity and flow rate sensor1includes a substrate2, a heat generating element3(i.e., heater), a temperature measuring element4, at least one lead wire5, and a fixing member6(i.e., fastener). The flow velocity and flow rate sensor1is a thermal flow velocity and flow rate sensor, and the temperature measuring element4detects temperature of heat generated from the heat generating element3in accordance with supply current. The flow velocity and flow rate sensor1detects flow velocity of air flowing around the heat generating element3and the temperature measuring element4on the basis of the fact that temperature of heat detected by the temperature measuring element4changes in accordance with flow velocity, and detects a flow rate with addition of a sectional area in a direction perpendicular to an air flow direction in a space where the air flows. The flow velocity and flow rate sensor1detects flow velocity (wind velocity) and a flow rate (wind volume) of air (wind) passing the flow velocity and flow rate sensor1.

The substrate2is a plate-shaped member made of glass epoxy, which is typically used for a printed circuit board. The substrate2includes a first portion2a, a second portion2bextending to be branched from the first portion2a, and an annular third portion2cextending from the first portion2aand surrounding the second portion2b. The substrate2has only to be made of a material having low heat conductivity, and examples of the materials include, in addition to the glass epoxy, polyamide and ceramic.

The first portion2ais larger in area than the second portion2band the third portion2c. The second portion2bconstitutes a flow velocity and flow rate detector of the flow velocity and flow rate sensor1, and is equipped with the heat generating element3and the temperature measuring element4. The third portion2cinhibits contact of any external object approaching the second portion2b. The first portion2ais provided with a through hole2dused to fix the lead wire5.

The first portion2aand the second portion2bhave surfaces provided with a circuit pattern8formed as a thin film made of copper or the like. The heat generating element3and the temperature measuring element4are general-purpose electronic components, and are equipped such that terminals of the elements3and4are soldered at appropriate points of the circuit pattern8provided in the second portion2b.

The heat generating element3generates heat in accordance with magnitude of supply current. The temperature measuring element4detects temperature of a medium increased in temperature by the heat generated at the heat generating element3. The temperature measuring element4is positioned adjacent to the heat generating element3so as to quickly detect temperature change of the medium. However, the heat generating element3and the temperature measuring element4are mounted on the substrate2so as to be spaced apart from each other in order to prevent heat generated at the heat generating element3from being transmitted directly to the temperature measuring element4without being transmitted via the medium.

The circuit pattern8provided in the first portion2ais equipped with an element group7including a plurality of elements other than the heat generating element3and the temperature measuring element4. The elements included in the element group7are general-purpose electronic components. The circuit pattern8provided on the surface of the first portion2ais partially provided with at least one land8a.

The lead wire5is an electric wire used for supply of electric current to the elements3and4and the element group7, and for transmission and reception of signals between the flow velocity and flow rate sensor1and a controller (seeFIG.4andFIG.5). The flow velocity and flow rate sensor1according to the present disclosure includes five lead wires5constituting a single set.

The land8ais a portion for connection of the lead wires5to the circuit pattern8. The flow velocity and flow rate sensor1according to the present disclosure includes five lands8aprovided on the substrate2, and the lead wires5are soldered to the lands8aone by one. The flow velocity and flow rate sensor1according to one or more embodiments exemplifies the case where the lead wires5are soldered to the circuit pattern8. Each of the lead wires5may alternatively be connected to the circuit pattern8via a connector.

The five lead wires5are fixed to the substrate2by the fixing member6. In the flow velocity and flow rate sensor1according to the present disclosure, the fixing member6is a resin cable tie. The lead wires5are tied by the fixing member6inserted through the through hole2din the substrate2so as to be fixed to the substrate2. In the flow velocity and flow rate sensor1, the first portion2ahas a substantially L shape, and the second portion2bprojects in a direction substantially perpendicular to a direction of connection of the lead wires5to the substrate2.

The flow velocity and flow rate sensor1has a gray patterned portion inFIG.1, and the portion is coated with a “resin”. The “resin” herein corresponds to a resin10depicted inFIG.2andFIG.3. The resin10is higher in heat conductivity than air, and has a property of not allowing liquid such as water to flow therethrough. In the flow velocity and flow rate sensor1according to the present disclosure, the resin10is thermosetting epoxy resin. One or more embodiments exemplify a thermosetting epoxy resin as the resin10. The resin10can be appropriately selected from resins being higher in heat conductivity than air and having the property of not allowing liquid such as water to flow therethrough.

As depicted inFIG.1toFIG.3, the heat generating element3mounted on the substrate2is coated with the resin10. The following description refers to a heat generating portion11including the heat generating element3mounted on the substrate2and a portion provided with the resin10coating the heat generating element3(seeFIG.2andFIG.3).

The temperature measuring element4mounted on the substrate2is coated with the resin10. The following description refers to a temperature measuring portion12including the temperature measuring element4mounted on the substrate2and a portion provided with the resin10coating the temperature measuring element4(seeFIG.2andFIG.3).

As depicted inFIG.2andFIG.3, the resin10fills a space between the heat generating portion11and the temperature measuring portion12on the substrate2in the flow velocity and flow rate sensor1. In the flow velocity and flow rate sensor1, the resin10in the heat generating portion11, the resin10in the temperature measuring portion12, and the resin10filled therebetween constitute a joint portion13. The joint portion13thermally connects, by means of the resin10, the heat generating element3and the temperature measuring element4. The joint portion13according to one or more embodiments includes the resin10existing outside a gap between the heat generating element3and the temperature measuring element4. The joint portion13may alternatively be formed only by the resin10existing in the gap between the heat generating element3and the temperature measuring element4.

For convenience of description,FIG.2andFIG.3indicate boundaries for the heat generating portion11, the temperature measuring portion12, and the resin10provided therebetween. The portions11and12and the resin10may alternatively be provided integrally without any boundaries.

The expression “thermally connect” herein indicates a state where the heat generating element3and the temperature measuring element4are disposed to be heat exchangeable via the resin10, and excludes a case where the heat generating element3and the temperature measuring element4are disposed in direct contact with each other so as to be heat exchangeable.

In the flow velocity and flow rate sensor1, the heat generating element3and the temperature measuring element4are thermally connected to each other via the joint portion13made of the resin10. In the flow velocity and flow rate sensor1, heat generated at the heat generating element3is transmitted to the temperature measuring element4via the resin10.

The thermosetting epoxy resin has heat conductivity from about 0.17 W/(mK) to about 0.21 W/(mK), and air has heat conductivity of about 0.0246 W/(mK) at 280 K. Accordingly, the heat conductivity of the thermosetting epoxy resin is higher by about ten times than the heat conductivity of air. In comparison to a case where the heat generating element3and the temperature measuring element4interpose air therebetween, the heat generating element3and the temperature measuring element4interposing the resin10have higher heat transmission efficiency from the heat generating element3to the temperature measuring element4.

As described above, the flow velocity and flow rate sensor1according to the present disclosure includes the substrate2, the heat generating element3mounted on the substrate2, the temperature measuring element4mounted on the substrate2, and the joint portion13made of the resin10filled between the heat generating element3and the temperature measuring element4and thermally connecting the heat generating element3and the temperature measuring element4.

In the flow velocity and flow rate sensor1according to the present disclosure, the resin10is interposed between the heat generating element3and the temperature measuring element4. The resin10is higher in heat conductivity than air. In comparison to the case where air is interposed between the heat generating element3and the temperature measuring element4, the resin10improves heat transmission efficiency from the heat generating element3to the temperature measuring element4. The flow velocity and flow rate sensor1is thus improved in temperature measurement accuracy of the temperature measuring element4for heat generated at the heat generating element3. The flow velocity and flow rate sensor1is accordingly improved in flow velocity and flow rate measurement accuracy than a flow velocity and flow rate sensor including a heat generating element and a temperature measuring element that interpose air therebetween.

As described above, the flow velocity and flow rate sensor1according to the present disclosure includes the heat generating portion11where the heat generating element3is coated with the resin10, and the temperature measuring portion12where the temperature measuring element4is coated with the resin10. The heat generating element3and the temperature measuring element4are each coated with the resin10in the flow velocity and flow rate sensor1, to inhibit any moisture or dust adhering to a surface of the flow velocity and flow rate sensor1from adhering directly to the heat generating element3and the temperature measuring element4. The flow velocity and flow rate sensor1can thus inhibit deterioration of the heat generating element3and the temperature measuring element4due to any moisture or dust adhering to the surface of the flow velocity and flow rate sensor1. The flow velocity and flow rate sensor1can accordingly inhibit deterioration in measurement accuracy due to any moisture or dust adhering to the surface. The flow velocity and flow rate sensor1thus configured can be disposed in a place where dew condensation is likely to occur.

As depicted inFIG.1, in the flow velocity and flow rate sensor1, the element group7excluding the heat generating element3and the temperature measuring element4is coated with a resin (the resin10depicted inFIG.2andFIG.3).

As depicted inFIG.1, the element group7is disposed on the substrate2to have an area larger than an area where the heat generating element3and the temperature measuring element4are disposed. Specifically, in the flow velocity and flow rate sensor1according to the present disclosure, the element group7is disposed in the area about30times the area where the heat generating element3and the temperature measuring element4are disposed. In the flow velocity and flow rate sensor1according to one or more embodiments, the resins10form layers coating the elements3,4, and7and being substantially equal in thickness.

In this case, the resin10coating the element group7has quantity (volume) about 30 times quantity of the resin10in the joint portion13(total quantity of the resin10in the heat generating portion11, the resin10in the temperature measuring portion12, and the resin10interposed therebetween). In the flow velocity and flow rate sensor1, the resin10coating the element group7accordingly has quantity (volume) larger than total quantity (volume) of the resins10in the joint portion13.

In this manner, in the flow velocity and flow rate sensor1according to the present disclosure, the resin10on the substrate2other than the joint portion13is larger in quantity than the resins10in the joint portion13. In this case, heat generated from the element group7of the flow velocity and flow rate sensor1has larger quantity of heat diffused to the resin10outside the joint portion13than quantity of heat diffused to the resins10in the joint portion13. Heat generated at the element group7can thus be inhibited from influencing temperature measurement accuracy of the temperature measuring element4. The flow velocity and flow rate sensor1can accordingly inhibit deterioration in measurement accuracy.

As depicted inFIG.1, in the flow velocity and flow rate sensor1, the substrate2is entirely coated with a resin (the resin10depicted inFIG.2andFIG.3). In the flow velocity and flow rate sensor1, the resin10also coats portions excluding points equipped with the heat generating element3, the temperature measuring element4, and the element group7.

In an exemplary case where the resin10coats only specific points equipped with the heat generating element3, the temperature measuring element4, the element group7, and the like, coating work needs adjusting applied quantity by means of an applicator or the like and applying the resin10only to the specific points.

In contrast, in the case where the resin10entirely coats the substrate2including the points equipped with the heat generating element3, the temperature measuring element4, and the element group7as in the flow velocity and flow rate sensor1, the coating work by means of the resin10is completed only by entirely soaking the substrate2in a tank reserving the resin10. In this case, the heat generating element3, the temperature measuring element4, and the element group7can be coated with the resin10, and the joint portion13can be formed simultaneously.

In the flow velocity and flow rate sensor1according to the present disclosure, the substrate2is entirely coated with the resin10. Accordingly, the heat generating element3and the temperature measuring element4mounted on the substrate2can be efficiently coated with the resin10, and the joint portion13can be formed efficiently. The flow velocity and flow rate sensor1according to the present disclosure can be efficiently manufactured only by entirely soaking the substrate2in the tank reserving the resin10.

[Connection Mode of Lead Wires]

If the substrate2and each of the lead wires5have a smaller contact area at a connection point between the substrate2and the lead wire5, a contact portion thereof typically has larger electrical resistance to generate more heat. As depicted inFIG.1, in the flow velocity and flow rate sensor1according to the present disclosure, the lead wires5are soldered respectively to the lands8aon the substrate2. Accordingly, in the flow velocity and flow rate sensor1, the substrate2and each of the lead wires5have a larger contact area in comparison to a case where the substrate2and the lead wire5are connected by means of a connector. This configuration can thus inhibit heat generation from the connection point between the substrate2and the lead wire5.

The substrate2and the lead wire5do not interpose any connector or the like therebetween in the flow velocity and flow rate sensor1, to efficiently discharge heat generated from the element group7to the lead wire5. Heat generated at the element group7can thus be inhibited from influencing temperature measurement accuracy of the temperature measuring element4. The flow velocity and flow rate sensor1can accordingly inhibit deterioration in measurement accuracy.

[Fixing Mode of Lead Wires]

As depicted inFIG.1, in the flow velocity and flow rate sensor1, the substrate2is entirely coated with a resin (the resin10depicted inFIG.2andFIG.3), and the lead wires5and the fixing member6are coated with the resin10. The lead wires5are fixed to the substrate2by the fixing member6in the flow velocity and flow rate sensor1. This configuration can thus inhibit displacement of the lead wires5upon application of tension to the lead wires5. The flow velocity and flow rate sensor1is accordingly less likely to have separation of the resin10coating peripheries of the lead wires5. The flow velocity and flow rate sensor1according to one or more embodiments exemplifies the case where the lead wires5are fixed to the substrate2by means of the fixing member6. The fixing member6may be excluded in an exemplary case where the flow velocity and flow rate sensor1includes the lead wires5each connected to the circuit pattern8via a connector.

[Entire Configuration of Air Conditioner]

FIG.4depicts an air conditioner20according to one or more embodiments of the present disclosure. The air conditioner20depicted inFIG.4includes a main unit21, a plurality of fan units26, and a controller35.

The air conditioner20, as well as a supply air duct31and a return air duct34connecting the air conditioner20and a space50, constitute an air conditioning system30. The space50serves as an air conditioning target space of the air conditioning system30, and movement of interior air is restricted by a ceiling, a floor, and a wall. Examples of the space50include a room in a building. The air conditioner20supplies the space50with conditioned air and returns air in the space50to condition air in the space50.

The supply air duct31distributes supply air SA sent from the main unit21to the plurality of fan units26. The supply air duct31includes a main pipe32and a branch pipe33branching from the main pipe32. The return air duct34returns return air RA in the space50to the main unit21.

FIG.4representatively exemplifies the air conditioning system30that includes the air conditioner20having two fan units26and installed for the single space50. The air conditioner20may alternatively include three or more fan units26. The space50to be air conditioned by the air conditioner20may be divided into two or more subspaces50. In this case, each of the subspaces50is provided with one or more fan units26.

The main unit21includes a first flow velocity and flow rate sensor1A, a first fan22, a heat exchanger23, a temperature sensor24, and a water volume control valve25. The first fan22, the heat exchanger23, the first flow velocity and flow rate sensor1A, the temperature sensor24, and the water volume control valve25are disposed in the main unit21.

The first flow velocity and flow rate sensor1A corresponds to the flow velocity and flow rate sensor1according to the present disclosure, and is positioned so as to detect flow velocity and a flow rate of air sent from the first fan22. The flow rate detected by the first flow velocity and flow rate sensor1A corresponds to a flow rate of air flowing in the main pipe32of the supply air duct31, and also corresponds to a total flow rate of the supply air SA supplied from the plurality of fan units26to the space50.

The first fan22is capable of sending air having the total flow rate and supplied to the space50. Air blown out of the first fan22is to entirely flow into the supply air duct31. The first fan22includes a fan motor22a.

The heat exchanger23is supplied with cold water or the like as a heating medium, from a heat source unit38. The heating medium supplied to the heat exchanger23may alternatively be warm water or the like.

The temperature sensor24detects temperature of the supply air SA sent from the first fan22to the supply air duct31.

The water volume control valve25adjusts a flow rate of the heating medium supplied from the heat source unit38to the heat exchanger23, and adjusts quantity of heat supplied to the return air RA passing the heat exchanger23.

The return air RA having passed the return air duct34and having returned from the space50to the main unit21is sent to the supply air duct31through the heat exchanger23by means of the first fan22. The return air RA having returned from the space50corresponds to air having existed in the space50. The return air RA turns into conditioned air by heat exchange with the heating medium flowing in the heat exchanger23while passing the heat exchanger23, and is sent as the supply air SA by the first fan22.

The air conditioning system30according to the present disclosure has an air circulation path including a range for ventilation of the supply air SA, which will be referred to as a “secondary region” of the heat exchanger23, and a range for ventilation of the return air RA, which will be referred to as a “primary region” of the heat exchanger23. The secondary region of the heat exchanger23corresponds to a range from the heat exchanger23to a terminal end, adjacent to the space50, of the branch pipe33. The primary region of the heat exchanger23corresponds to a range from the space50to the heat exchanger23.

Particularly when the heat source unit38supplies the heat exchanger23with cold water, the supply air SA flowing in the secondary region of the heat exchanger23is cooled in the heat exchanger23to have high relative humidity and be likely to cause dew condensation. With the supply air SA in such a state, the first flow velocity and flow rate sensor1A disposed in the secondary region of the heat exchanger23may have dew condensation on a surface thereof.

The fan units26each include a second flow velocity and flow rate sensor1B, a second fan27, and a casing28. Each of the fan units26is installed at a halfway point of the branch pipe33.

The second flow velocity and flow rate sensor1B corresponds to the flow velocity and flow rate sensor1according to the present disclosure. In the air conditioner20according to the present disclosure, the second flow velocity and flow rate sensor1B is installed at a bell mouth40provided to the second fan27(seeFIG.7). The second flow velocity and flow rate sensor1B detects flow velocity and a flow rate of air sent from the second fan27. The flow rate detected by the second flow velocity and flow rate sensor1B corresponds to a flow rate in the branch pipe33connected to the corresponding fan unit26, and also corresponds to a flow rate of the supply air SA supplied from the fan unit26to the space50.

The second fan27supplies the space50with the supply air SA from the fan unit26. The second fan27includes a fan motor27a.

The casing28has a blow-in port28aand a blow-out port28b. The branch pipe33connects the blow-in port28ato the main pipe32. The branch pipe33connects the blow-out port28bto the space50. The second fan27sucks the supply air SA from the branch pipe33connected to the blow-in port28a, and supplies the supply air SA to the branch pipe33connected to the blow-out port28b.

As depicted inFIG.4, each of the fan units26is disposed in the secondary region of the heat exchanger23, and thus allows the supply air SA to flow therein. When the supply air SA flowing to the fan unit26has high relative humidity and is likely to cause dew condensation, the second flow velocity and flow rate sensor1B may have dew condensation on a surface thereof.

As depicted inFIG.5, the controller35includes a first controller36and a plurality of second controllers37. The first controller36and each of the second controllers37are connected to each other.

The controller35is configured to receive information on a flow rate of the supply air SA (necessary supply air volume) to be supplied to the space50by the plurality of second fans27.

The first controller36stores a flow rate control program for the first fan22. The first controller36outputs necessary commands to the first fan22and the second controllers37. The first controller36controls a number of revolutions of the fan motor22ain the first fan22.

The first controller36is connected with the first flow velocity and flow rate sensor1A. The first flow velocity and flow rate sensor1A detects a flow rate value to be outputted from the first flow velocity and flow rate sensor1A to the first controller36.

The first controller36is connected with the temperature sensor24. The temperature sensor24detects a value (temperature) to be inputted to the first controller36.

The first controller36stores, as needed, detection values of the first flow velocity and flow rate sensor1A and the temperature sensor24. The first controller36reads the stored detection values of the first flow velocity and flow rate sensor1A and the temperature sensor24, and calculates a flow rate target value (total target flow rate to be supplied to the space50) of the first fan22.

The first controller36stores an opening degree control program for the water volume control valve25. The first controller36outputs a necessary command to the water volume control valve25.

The second controllers37each store a flow rate control program for a corresponding one of the second fans27. The second controllers37are provided for the fan units26one by one. Each of the second controllers37outputs a necessary command to the corresponding second fan27.

Each of the second controllers37is connected with the second flow velocity and flow rate sensor1B. The second flow velocity and flow rate sensor1B detects a flow rate value to be inputted to the second controller37from the second flow velocity and flow rate sensor1B. The flow rate detected by the second flow velocity and flow rate sensor1B corresponds to the flow rate in the branch pipe33, and also corresponds to supply air volume from each of the fan units26to the space50.

The second controllers37is connected with a remote sensor39. The remote sensor39functions as a temperature sensor. The remote sensor39is configured to output, to the corresponding second controller37, data indicating temperature of the return air RA in the space50.

The second controller37stores, as needed, the flow rate target value outputted from the first controller36and a detection value of the second flow velocity and flow rate sensor1B. The second controller37reads the flow rate target value and the detection value of the second flow velocity and flow rate sensor1B thus stored, and calculates a number-of-revolutions target value of the second fan27. The second controller37controls a number of revolutions of the fan motor27ain the second fan27in accordance with the number-of-revolutions target value thus calculated.

Each of the second controllers37outputs information on the necessary supply air volume to the first controller36. The first controller36determines an output to be requested to the first fan22(the number of revolutions of the fan motor22a) in accordance with the information on the necessary supply air volume acquired from the second controller37.

[Flow Velocity and Flow Rate Sensor of Air Conditioner20]

In the air conditioner20according to the present disclosure, the first flow velocity and flow rate sensor1A and the second flow velocity and flow rate sensor1B are disposed in the secondary region of the heat exchanger23. The first flow velocity and flow rate sensor1A and the second flow velocity and flow rate sensor1B are each disposed in a state where dew condensation may occur on the surface.

The first flow velocity and flow rate sensor1A and the second flow velocity and flow rate sensor1B each correspond to the flow velocity and flow rate sensor1according to the present disclosure. As described earlier, the heat generating element3and the temperature measuring element4are each coated with the resin10in the flow velocity and flow rate sensor1, to inhibit deterioration in flow velocity and flow rate measurement accuracy even when the surface has dew condensation. The air conditioner20accordingly inhibits deterioration in flow velocity and flow rate measurement accuracy even when the first flow velocity and flow rate sensor1A and the second flow velocity and flow rate sensor1B each have the surface provided with dew condensation.

Adoption of the flow velocity and flow rate sensor1according to the present disclosure achieves provision of the air conditioner20configured to measure supply air volume in the secondary region of the heat exchanger23, where dew condensation is likely to occur. It is possible to provide the air conditioner20including the main unit21having the heat exchanger23, and the plurality of fan units26connected to the secondary region of the heat exchanger23in the main unit21by means of the supply air duct31, and configured to measure supply air volume of each of the fan units26with use of the separate flow velocity and flow rate sensor1.

As described earlier, the heat generating element3and the temperature measuring element4are thermally connected to each other by the joint portion13made of the resin10in the flow velocity and flow rate sensor1, for improvement in flow velocity and flow rate measurement accuracy. In the air conditioner20, the flow rate target value of the first fan22is calculated with reference to the flow rate value detected by the first flow velocity and flow rate sensor1A. The air conditioner20is thus improved in calculation accuracy for the flow rate target value of the first fan22.

In the air conditioner20, the number-of-revolutions target value of the second fan27is calculated with reference to the flow rate value detected by the second flow velocity and flow rate sensor1B. The air conditioner20is thus improved in calculation accuracy for the number-of-revolutions target value of the second fan27.

The air conditioner20according to the present disclosure is thus improved in calculation accuracy for the flow rate target value of the first fan22and calculation accuracy for the number-of-revolutions target value of each of the second fans27, as well as flow rate control accuracy.

[Air Conditioner According to Different Embodiments]

As depicted inFIG.6, the main unit21in the air conditioner20according to the present disclosure may exclude the first fan22, the first flow velocity and flow rate sensor1A, and the temperature sensor24.

When the air conditioner20is configured as depicted inFIG.6, the first controller36acquires the detection value of the second flow velocity and flow rate sensor1B to be inputted to the second controller37for each of the fan units26. The first controller36calculates a flow rate of the return air RA passing the heat exchanger23in the main unit21, from a sum total of the supply air SA flowing in the fan units26.

The first controller36acquires a temperature detection value of the return air RA to be inputted to the second controller37from each of the remote sensors39. The first controller36calculates quantity of heat to be supplied to the return air RA passing the heat exchanger23and the flow rate of the supply air SA to be sent to each of the spaces50, from the temperature of the return air RA.

In accordance with calculation results of the quantity of heat to be supplied to the return air RA and the flow rate of the supply air SA to be sent to each of the spaces50, the first controller36calculates separate flow rate target values of the second fans27, and a command value for an opening degree necessary for the water volume control valve25. The first controller36outputs a necessary command to the water volume control valve25.

The second controllers37each receive the flow rate target value of the corresponding second fan27calculated by the first controller36. Each of the second controllers37stores, as needed, the flow rate target value outputted from the first controller36and the detection value of the second flow velocity and flow rate sensor1B. The flow rate value detected by the second flow velocity and flow rate sensor1B is inputted to the second controller37. The second controller37reads the flow rate target value and the detection value of the second flow velocity and flow rate sensor1B thus stored, and calculates the number-of-revolutions target value of the second fan27.

In the air conditioner20depicted inFIG.6, the number-of-revolutions target value of each of the second fans27is calculated with reference to the flow rate value detected by a corresponding one of the second flow velocity and flow rate sensors1B. The air conditioner20is thus improved in calculation accuracy for the number-of-revolutions target value of the second fan27.

The air conditioner20depicted inFIG.6is accordingly improved in calculation accuracy for the number-of-revolutions target value of each of the second fans27and flow rate control accuracy.

As described above, the air conditioner20according to the present disclosure includes the heat exchanger23and the flow velocity and flow rate sensor1having the substrate2, and the flow velocity and flow rate sensor1including the heat generating portion11having the heat generating element3mounted on the substrate2and the resin10coating the heat generating element3, the temperature measuring portion12having the temperature measuring element4mounted on the substrate2and the resin10coating the temperature measuring element4, the joint portion13thermally connecting the heat generating portion11and the temperature measuring portion12by means of the resin10filled between the heat generating portion11and the temperature measuring portion12, and the flow velocity and flow rate sensor1is disposed in an air flow in a secondary region of the heat exchanger23. In this case, it is possible to provide the air conditioner20improved in flow velocity and flow rate measurement accuracy of the flow velocity and flow rate sensor1.

[Disposition of Flow Velocity and Flow Rate Sensor1]

In the air conditioner20, the second flow velocity and flow rate sensor1B is disposed in each of the fan units26having a flow of the supply air SA, and the second flow velocity and flow rate sensor1B individually measures supply air volume of each of the fan units26. In the air conditioner20, a corresponding one of the second controllers37and the first controller36receive a measurement value of supply air volume by each of the second flow velocity and flow rate sensors1B and execute feedback control to more accurately match the supply air volume of each of the fan units26to the flow rate target value calculated by the first controller36. The air conditioner20thus configured can condition air more appropriately in accordance with a state of the space50corresponding to each of the fan units26.

[Attachment Mode of Flow Velocity and Flow Rate Sensor]

As depicted inFIG.7, the second flow velocity and flow rate sensor1B is attached to the bell mouth40provided at a blow-in port27bof the second fan27. The bell mouth40has a function of rectifying air sucked into the blow-in port27bof the second fan27.

FIG.8A,FIG.8B,FIG.9A, andFIG.9Beach depict the bell mouth40attached to the second fan27. As depicted inFIG.9AandFIG.9B, the bell mouth40includes a body40ahaving a ring shape. The body40ahas a radial interior provided with an air suction hole40b. The air suction hole40bcommunicates with the blow-in port27bof the second fan27in a state where the bell mouth40is attached to the second fan27.FIG.9Adepicts a front side of the bell mouth40. The front side of the bell mouth40is opposite to a surface in contact with the second fan27when the bell mouth40is attached to the second fan27.

The body40ais provided with a holder41for disposition of the second flow velocity and flow rate sensor1B. The holder41has a flat surface41a, a wall41b, and a bottom41c. The flat surface41ais perpendicular to a center axis direction of the air suction hole40b, and is formed on the body40a. The wall41bis positioned to surround the flat surface41aand projects forward from the body40a. The bottom41cseals a bottom surface in a range surrounded with the wall41band not provided with the body40a. The wall41badjacent to the air suction hole40bis provided with a plurality of grooves41dpenetrating the holder41from inside to outside. The bottom41cis partially provided with a vent hole41e.

As depicted inFIG.8AandFIG.8B, in the second flow velocity and flow rate sensor1B, the first portion2aof the substrate2is disposed inside the holder41surrounded with the wall41b. In this case, the second portion2band the third portion2cof the substrate2are respectively fitted in the plurality of grooves41d, and have tip ends positioned outside the holder41. The heat generating portion11and the temperature measuring portion12provided at the tip end of the second portion2bare thus disposed outside the holder41.

In the state where the second flow velocity and flow rate sensor1B is disposed in the holder41, the heat generating portion11and the temperature measuring portion12are positioned inside the air suction hole40bwhen viewed in the center axis direction of the air suction hole40b. The heat generating portion11and the temperature measuring portion12are disposed in an air flow sucked into the second fan27via the bell mouth40.

As depicted inFIG.8A, the air conditioner20according to the present disclosure is provided with a cover42protecting the second flow velocity and flow rate sensor1B disposed in the holder41. The cover42is fixed to the holder41by means of a screw43. The cover42is provided with a vent hole42aand a projection42b.

The vent hole42ais positioned to face the heat generating portion11and the temperature measuring portion12in the state where the cover42is fixed to the holder41by means of the screw43. Accordingly, air sucked into the second fan27via the bell mouth40flows to peripheries of the heat generating portion11and the temperature measuring portion12through the vent hole42a.

FIG.8Bdepicts a disposition state of the second flow velocity and flow rate sensor1B with respect to the holder41with the cover42being removed. The projection42bis positioned to face the flat surface41aof the holder41in the state where the cover42is fixed to the holder41by means of the screw43. The projection42bhas a projecting height set such that the projection42band the flat surface41ainterpose a gap substantially equal to thickness of the first portion2ain the state where the cover42is fixed to the holder41by means of the screw43. In such a configuration, the first portion2aof the substrate2is interposed between the flat surface41aand the projection42bin the state where the cover42is fixed to the holder41by means of the screw43.

In the air conditioner20, the second flow velocity and flow rate sensor1B is interposed between the flat surface41aand the projection42b, to regulate displacement of the second flow velocity and flow rate sensor1B in the holder41. The second flow velocity and flow rate sensor1B is thus stable in terms of its posture in the holder41, so that the second flow velocity and flow rate sensor1B can accurately measure the flow rate of the second fan27.

In the flow velocity and flow rate sensor1, the second portion2bprojects in the direction substantially perpendicular to the direction of connection of the lead wires5to the substrate2. In such a configuration, the lead wires5led out of the holder41are directed along a tangent of the body40a. Accordingly, the lead wires5led out of the holder41can be easily handled, and can be disposed in a compact manner with less protrusion of the lead wires5from the bell mouth40.

At least part of the embodiments described above may be appropriately combined with each other.

[Action and Effects of Embodiments]

Measurement accuracy of the thermal flow velocity and flow rate sensor is improved effectively by increase in heat transmission efficiency from the heat generating element to the temperature measuring element and a configuration enabling the temperature measuring element to detect heat generated at the heat generating element as quickly as possible. However, the heat generating element and the temperature measuring element interpose air therebetween in the thermal flow velocity and flow rate sensor. The heat transmission efficiency from the heat generating element to the temperature measuring element is principally determined in accordance with heat conductivity of air. It is accordingly difficult to increase heat transmission efficiency from the heat generating element to the temperature measuring element to improve measurement accuracy of the thermal flow velocity and flow rate sensor.

One or more embodiments of the present disclosure provide a thermal flow velocity and flow rate sensor that can be improved in flow velocity and flow rate measurement accuracy, and an air conditioner including the thermal flow velocity and flow rate sensor.

In one or more embodiments, the thermal flow velocity and flow rate sensor1includes: a substrate2; a heat generating element3mounted on the substrate2; a temperature measuring element4mounted on the substrate2; and a joint portion13made of a resin10filled between the heat generating element3and the temperature measuring element4and thermally connecting the heat generating element3and the temperature measuring element4; a lead wire5connected to the substrate2; and a fixing member6fixing the lead wire5to the substrate2, wherein the lead wire5is soldered to the substrate2, and the lead wire5and the fixing member6are coated with the resin10.

In the thermal flow velocity and flow rate sensor1thus configured, the resin10is interposed between the heat generating element3and the temperature measuring element4. Such a resin is higher in heat conductivity then air. In comparison to a case where the heat generating element3and the temperature measuring element4interpose air therebetween, the thermal flow velocity and flow rate sensor1has higher heat transmission efficiency from the heat generating element3to the temperature measuring element4. This configuration improves measurement accuracy of the temperature measuring element4, for improvement in flow velocity and flow rate measurement accuracy. In this case, the substrate2and the lead wire5have a larger contact area in comparison to a case where the substrate2and the lead wire5are connected by means of a connector. This configuration can thus inhibit heat generation from a connection point between the substrate2and the lead wire5. In this case, the resin10is less likely to be separated upon application of tension to the lead wire5.

In one or more embodiments, the thermal flow velocity and flow rate sensor1further includes: a heat generating portion11including the heat generating element3coated with the resin10; and a temperature measuring portion12including the temperature measuring element4coated with the resin10.

In this case, the heat generating element3and the temperature measuring element4are each coated with the resin10to inhibit any dust, moisture, and the like from adhering to the heat generating element3and the temperature measuring element4. This configuration can accordingly inhibit deterioration in flow velocity and flow rate measurement accuracy due to adhesion of dust, moisture, and the like.

In one or more embodiments, the substrate2may be entirely coated with the resin10.

In this case, the heat generating element3and the temperature measuring element4mounted on the substrate2can be efficiently coated with the resin10, and the joint portion13can be formed efficiently. The thermal flow velocity and flow rate sensor1can thus be manufactured efficiently.

In one or more embodiments, the resin10on the substrate2not provided with the heat generating portion11, the temperature measuring portion12, or the joint portion13may be larger in quantity than the resin10at the joint portion13.

In this case, heat generated from portions other than the heat generating portion11and the temperature measuring portion12in the thermal flow velocity and flow rate sensor1has larger quantity of heat diffused to the resin10outside the joint portion13than quantity of heat diffused to the resin10in the joint portion13. This configuration can thus inhibit heat generated at the portions other than the heat generating portion11and the temperature measuring portion12in the thermal flow velocity and flow rate sensor1, from influencing the heat generating element3and the temperature measuring element4.

In one or more embodiments, an air conditioner20includes: a heat exchanger23, and a thermal flow velocity and flow rate sensor1including a substrate2, a heat generating portion11having a heat generating element3mounted on the substrate2and a resin10coating the heat generating element3, a temperature measuring portion12having a temperature measuring element4mounted on the substrate2and the resin10coating the temperature measuring element4, and a joint portion13thermally connecting the heat generating portion11and the temperature measuring portion12by means of the resin10filled between the heat generating portion11and the temperature measuring portion12, in which the thermal flow velocity and flow rate sensor1is disposed in an air flow in a secondary region of the heat exchanger23.

In this case, it is possible to provide the air conditioner20improved in flow velocity and flow rate measurement accuracy of the thermal flow velocity and flow rate sensor1.

REFERENCE SIGNS LIST

1flow velocity and flow rate sensor1A first flow velocity and flow rate sensor1B second flow velocity and flow rate sensor2substrate3heat generating element4temperature measuring element5lead wire6fixing member10resin11heat generating portion p112temperature measuring portion13joint portion20air conditioner23heat exchanger