JP5100800B2 - Snow melting equipment - Google Patents

Description

  The present invention relates to a snow melting device that melts snow in a snow melting target region.

  2. Description of the Related Art Conventionally, a snow melting device is known in which a heat medium heated by a hot water supply device is circulated through a heat radiating pipe embedded in a snow melting target region of a road surface to melt snow accumulation in the snow melting target region (for example, Patent Documents). 1). Such a type of snow melting apparatus is provided with a plurality of operation modes. The user selects one of the operation modes with a remote controller or the like depending on the facility environment in which the snow melting device is used.

  The operation modes include, for example, an automatic operation mode and a heat retention operation mode. In the automatic operation mode, the snow melting operation is executed during snowfall and when the road surface temperature is equal to or lower than the reference temperature. That is, since the snow melting operation is executed at the stage of snow accumulation, it is used in general facilities. On the other hand, in the heat insulation operation mode, the snow melting operation is executed during snowfall or when the road surface temperature is equal to or lower than the reference temperature. That is, since the snow melting operation is performed even when the road surface is frozen, it is used particularly in facilities such as hospitals and slopes where road surface freezing is not allowed.

JP 2006-342578 A

  However, if the above-mentioned heat insulation operation mode is selected, snow melting operation is always executed just when the road surface temperature falls below the reference temperature regardless of whether snow falls or not, and depending on the facility environment, gas and power are consumed wastefully. There was a problem of doing.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a snow melting device that can reduce running costs.

  A snow melting device according to claim 1 of the present invention includes a hot water supply device incorporating a burner that is a heat source, and circulates a heat medium supplied from the hot water supply device through a pipe embedded in a snow melting target region. In a snow melting device that melts snow in a snow melting target region, a snowfall sensor that detects snowfall in the snow melting target region, a road surface temperature sensor that detects a road surface temperature in the snow melting target region, and snowfall detection by the snowfall sensor The road surface temperature detected by the road surface temperature sensor when the snowfall is detected by the measuring means for measuring the elapsed time from when the snowfall is stopped, or when the snowfall sensor does not detect snowfall, When the temperature is lower than the reference temperature, snowfall is detected by the first heat retaining operation mode for allowing the snowmelt operation by the snowmelt device and the snowfall sensor. The road surface temperature detected by the road surface temperature sensor is a reference temperature until the elapsed time measured by the measuring means reaches a predetermined time in a state where no snowfall is detected by the snowfall sensor. A second heat-retaining operation mode that permits snow-melting operation by the snow-melting device, and mode selection means for selecting one of the first heat-retaining operation mode and the second heat-retaining operation mode. .

  The snow melting device of the invention according to claim 2 includes a hot water supply device incorporating a burner as a heat source, and circulates a heat medium supplied from the hot water supply device through a pipe embedded in the snow melting target region, In the snow melting device that melts snow in the snow melting target region, a snowfall sensor that detects snowfall in the snow melting target region, a road surface temperature sensor that detects a road surface temperature in the snow melting target region, and snowfall by the snowfall sensor. The road surface temperature detected by the road surface temperature sensor when the snowfall is detected by the measuring means for measuring the elapsed time from when the snowfall sensor is no longer detected, or when no snowfall is detected by the snowfall sensor When the temperature is lower than the reference temperature, the first heat insulation operation mode for allowing the snow melting operation by the snow melting device and the snow detection by the snow sensor. Or when the road surface temperature detected by the road surface temperature sensor is lower than a reference temperature when no snow is detected by the snowfall sensor, the snow melting operation by the snow melting device is permitted, and the reference temperature Is set to be lower as the elapsed time becomes longer, and mode selection means for selecting one of the first heat insulation operation mode and the third heat insulation operation mode.

  According to a third aspect of the present invention, in addition to the configuration of the second aspect of the present invention, a snowfall prediction that determines a snowfall prediction that is a possibility of snowfall in the snowmelt target region based on an external input. In the third operation mode, the degree of lowering the reference temperature is changed in accordance with the snowfall prediction determined by the snowfall prediction determination means.

  According to a fourth aspect of the present invention, in addition to the configuration of the third aspect of the invention, in the third operation mode, as the snowfall prediction determined by the snowfall prediction determining means becomes lower, the reference It is characterized by increasing the degree of lowering the temperature.

  In the snow melting device according to the first aspect of the present invention, the heat medium supplied from the hot water supply device is circulated through the pipe embedded in the snow melting target region to melt snow in the snow melting target region. The mode selection means selects either the first heat insulation operation mode or the second heat insulation operation mode. When the first heat retention operation mode is selected, when snowfall is detected by the snowfall sensor, or when the road surface temperature detected by the road surface temperature sensor is lower than the reference temperature in the state where no snowfall is detected by the snowfall sensor Snow melting operation is permitted. The first heat insulation operation mode is selected when the snow melting operation is executed when the road surface is frozen, and particularly when used in facilities such as hospitals and slopes where road surface freezing is not allowed. When the second heat insulation operation mode is selected, when the snowfall is detected by the snowfall sensor, or when no snowfall is detected by the snowfall sensor, the elapsed time from when snowfall is no longer detected by the snowfall sensor becomes the predetermined time. If the road surface temperature detected by the road surface temperature sensor is less than the reference temperature before reaching the snow melting operation, the snow melting operation is permitted. In the second heat insulation operation mode, when a predetermined time has elapsed after the snowfall disappears, the snowmelt operation is not permitted until the next snowfall is detected regardless of the decrease in the road surface temperature. In other words, there is a high possibility that it will resume for a while after it has snowed. Therefore, the road surface temperature is checked until the predetermined time has elapsed after the snow has fallen, and if it is lower than the reference temperature, the snow melting operation is executed. If there is no snow after a predetermined time, the possibility of resuming snow is low, so the snow melting operation is stopped. The user can reduce the running cost of the snow melting device by properly using the first heat insulation operation mode and the second heat insulation operation mode.

  In the snow melting device according to the second aspect of the present invention, the heat medium supplied from the hot water supply device is circulated through the pipe embedded in the snow melting target region to melt snow in the snow melting target region. The mode selection means selects either the first heat retention operation mode or the third heat retention operation mode. When the first heat retention operation mode is selected, when snowfall is detected by the snowfall sensor, or when the road surface temperature detected by the road surface temperature sensor is lower than the reference temperature in the state where no snowfall is detected by the snowfall sensor Snow melting operation is permitted. The first heat insulation operation mode is selected when the snow melting operation is executed when the road surface is frozen, and particularly when used in facilities such as hospitals and slopes where road surface freezing is not allowed. When the third heat retention operation mode is selected, the reference temperature that serves as a reference for whether or not to permit the snow melting operation is set to be lower as the elapsed time from when snow has disappeared becomes longer. That is, as the time elapses from when the snowfall disappears, the condition for permitting the snowmelt operation becomes stricter, so that the probability that the snowmelt operation is executed becomes lower in the absence of snowfall. By properly using the first heat insulation operation mode and the third heat insulation operation mode, the running cost of the snow melting device can be reduced.

  Further, in the snow melting device of the invention according to claim 3, in addition to the effect of the invention of claim 2, the snowfall prediction determining means determines snowfall prediction in the snowmelt target region based on an external input. In the third heat insulation operation mode, the degree to which the reference temperature is lowered is changed according to the snowfall prediction determined by the snowfall prediction determining means. Thereby, the permission conditions of the snow melting operation can be changed according to the snowfall prediction.

  In addition, in the snow melting device of the invention according to claim 4, in addition to the effect of the invention of claim 3, in the third operation mode, the reference temperature is lowered as the snowfall prediction determined by the snowfall prediction determining means becomes lower. Increase the degree to do. Therefore, when the possibility of snowfall is low, the conditions for permitting the snowmelt operation become strict, and therefore, the probability that the snowmelt operation is performed becomes low in the absence of snowfall. Thereby, the amount of gas and the amount of power can be saved. On the contrary, if the possibility of snowfall is high, the conditions for permitting the snowmelt operation are relaxed, so that the probability of executing the snowmelt operation is increased in preparation for snowfall. Therefore, the frequency of performing the snow melting operation can be adjusted according to the possibility of snowfall.

1 is a schematic view showing a configuration of a snow melting device 1. FIG. 1 is a block diagram showing an electrical configuration of a snow melting device 1. FIG. It is a main flowchart of a snow melting operation control process. It is a flowchart of an operation start check process. It is a flowchart of an automatic driving | operation start check process. It is a flowchart of a heat insulation driving | operation start check process. It is a flowchart of a driving | running | working continuation check process. It is a flowchart of an automatic driving | operation continuation check process. It is a flowchart of a 1st heat retention driving | operation continuation check process. It is a flowchart of a 2nd heat retention driving | operation continuation check process. It is a flowchart of the 2nd heat retention driving | operation continuation check process (1st modification). 3 is a conceptual diagram of a table 1041. FIG. It is a flowchart of the 2nd heat retention driving | operation continuation check process (2nd modification).

  Hereinafter, a snow melting apparatus 1 according to an embodiment of the present invention will be described with reference to the drawings. These drawings are used to explain technical features that can be adopted by the present invention. The structure of the apparatus described below is merely an illustrative example, and is not intended to be limited to that unless otherwise specified.

  First, the configuration of the snow melting device 1 will be described with reference to FIG. The snow melting device 1 includes a hot water supply device 2 that is a parent device and hot water supply devices 3 and 4 that are child devices as heat source devices. Heat-dissipating heating pipes 19 are bent and embedded in the ground of the snow melting target area 6. In the snow melting device 1, the temperature of the ground in the snow melting target region 6 rises by flowing the antifreeze liquid heated by the hot water supply devices 2 to 4 through the heating pipe 19 as a heat medium. Thereby, the snow accumulation in the snow melting object area | region 6 can be melt | dissolved. The antifreeze liquid that has flowed through the heating pipe 19 returns to the hot water supply apparatuses 2 to 4 through various pipes 7 to 13 described later. The antifreeze liquid heated again by the hot water supply apparatuses 2 to 4 flows again through the heating pipe 19 via various pipes 14 to 17 described later. The snow melting device 1 can perform such a snow melting operation.

  Next, the structure of the hot water supply device 2 will be described with reference to FIG. The hot water supply device 2 functions as a master unit. At the bottom of the housing 2A of the hot water supply device 2, there are a gas inlet 41 through which gas flows, a water inlet 42 through which antifreeze returned through the heating pipe 19 flows, and an antifreeze heated in the housing 2A. A water outlet 43 for discharging water is provided. A burner 50 is provided in the combustion chamber of the housing 2A. A gas supply pipe 45 connected to the gas inlet 41 is connected to the burner 50. In the vicinity of the burner 50, a thermocouple 105 (see FIG. 2) for detecting the flame temperature, a frame rod 106 (see FIG. 2) for detecting misfire, and an igniter 107 (FIG. 2) for igniting the burner 50. Each) is provided.

  A gas electromagnetic valve 51 that opens and closes the gas flow path is provided on the upstream side of the gas supply pipe 45 through which the gas flows. A gas proportional valve 52 that adjusts the gas flow rate and adjusts the heating power of the burner 50 is provided on the downstream side. A pipe 46 through which the antifreeze liquid flows is provided between the water inlet 42 and the water outlet 43. A heat exchanger (not shown) is provided in the middle of the pipe 46. On the upstream side of the heat exchanger in the pipe 46, a flow rate sensor 56 for detecting the return flow rate of the antifreeze liquid flowing through the pipe 46, and a return temperature for detecting the return temperature of the antifreeze liquid (water temperature entering the hot water supply device 2). A thermistor 55 is provided.

  Further, the hot water supply device 2 includes a control device 5 (see FIG. 2) for controlling the snow melting operation of the snow melting device 1, and a remote controller 36 (corresponding to “mode selection means” of the present invention) for instructing the operation of the snow melting device 1. A snowfall sensor 38 for detecting snow accumulation in the snow melting target area 6 and a road surface temperature sensor 35 for detecting the road surface temperature of the snow melting target area 6 are provided. The remote controller 36 is provided with an abnormal lamp 37 for notifying that an abnormal antifreeze circulation has occurred during the snow melting operation of the snow melting device 1. In FIG. 1, the road surface temperature sensor 35 is installed in the approximate center of the snow melting target area 6, but the position is not limited.

  Next, the structure of the hot water supply apparatuses 3 and 4 will be described with reference to FIG. The hot water supply devices 3 and 4 function as slave units. The hot water supply apparatuses 3 and 4 have substantially the same configuration as the hot water supply apparatus 2. A gas inlet 61, a water inlet 62, and a water outlet 63 are provided at the bottom of the housing 3 </ b> A of the water heater 3. A gas inlet 81, a water inlet 82, and a water outlet 83 are also provided at the bottom of the housing 4 </ b> A of the water heater 4. In the casings 3A and 4A of the hot water supply apparatuses 3 and 4, a burner 50, a gas supply pipe 45, a gas electromagnetic valve 51, a gas proportional valve 52, and a pipe 46 similar to the hot water supply apparatus 2 are provided.

  Next, the piping configuration of the snow melting device 1 will be described with reference to FIG. One end of the first return pipe 7 is connected to one end of the heating pipe 19 on the downstream side where the antifreeze liquid flows. The other end of the first return pipe 7 is connected to the bottom of an air separator 8 for separating air from the antifreeze supplied from the first return pipe 7. One end of the second return pipe 9 is further connected to the bottom of the air separator 8. The other end of the second return pipe 9 is provided with a branch portion 21 that branches into two flow paths. One end of the third return pipe 10 for supplying the antifreeze liquid to the hot water supply devices 2 to 4 is connected to one of the branch parts 21, and one end of a bypass pipe 18 to be described later is connected to the other.

  The 3rd return pipe 10 is extended over the hot-water supply apparatuses 2-4. The third return pipe 10 is provided with connecting portions 22, 23 and 24 in order from the upstream side to the downstream side in the direction in which the antifreeze liquid flows. One end of the branch pipe 11 is connected to the connection part 22. The other end of the branch pipe 11 is connected to the water inlet 42 of the hot water supply device 2. One end of the branch pipe 12 is connected to the connection part 23. The other end of the branch pipe 12 is connected to the water inlet 62 of the hot water supply device 3. One end of the branch pipe 13 is connected to the connection part 24. The other end of the branch pipe 13 is connected to a water inlet 82 of the hot water supply device 4. A hot water supply side pump 31 is provided on the upstream side of the third return pipe 10 and between the branch portion 21 and the connection portion 22. The hot water supply device side pump 31 adjusts the flow rate of the antifreeze supplied to the hot water supply devices 2 to 4. The hot water supply device side pump 31 is a DC pump driven by a direct current power source. Therefore, when the hot water supply side pump 31 is driven, the antifreeze liquid flowing through the third return pipe 10 is connected to the hot water supply apparatuses 2, 3, 4 from the connection parts 22, 23, 24 via the branch pipes 11, 12, 13. Flow into.

  On the other hand, one end of the forward pipe 17 for flowing the antifreeze heated by the hot water supply devices 2 to 4 to the heating pipe 19 is connected to one end of the heating pipe 19 on the upstream side where the antifreeze flows. Similar to the third return pipe 10, the forward pipe 17 extends over the hot water supply devices 2 to 4. The forward pipe 17 is provided with connecting portions 25, 26, and 27 in order from the downstream side to the upstream side in the direction in which the antifreeze liquid flows. One end of the branch pipe 14 is connected to the connection portion 25. The other end of the branch pipe 14 is connected to the water outlet 43 of the hot water supply device 2. One end of the branch pipe 15 is connected to the connection part 26. The other end of the branch pipe 15 is connected to the water outlet 63 of the hot water supply device 3. One end of the branch pipe 16 is connected to the connection portion 27. The other end of the branch pipe 16 is connected to the water outlet 83 of the hot water supply device 3. The antifreeze liquid heated by each of the hot water supply devices 2 to 4 flows from the water outlets 43, 63, and 83 to the branch pipes 14, 15, and 16 and flows from the connecting portions 25, 26, and 27 to the forward pipe 17 to join. , Flowing toward the heating pipe 19.

  Further, the antifreeze flowing through the bypass pipe 18 having one end connected to the branching portion 21 of the second return pipe 9 and the antifreeze flowing through the forward pipe 17 join downstream of the connection section 25 in the forward pipe 17. A junction 28 is provided. The bypass pipe 18 allows a part of the antifreeze flowing through the second return pipe 9 to flow to the forward pipe 17 as it is without passing through the hot water supply devices 2 to 4. The bypass pipe 18 is provided with a heat radiation side pump 32. The heat radiation side pump 32 adjusts the total circulation amount in the snow melting device 1 by adjusting the flow rate of the antifreeze flowing through the bypass pipe 18. The heat radiation side pump 32 is also a DC pump driven by a DC power source. A forward temperature thermistor 58 for detecting the forward temperature of the antifreeze flowing through the forward pipe 17 is provided on the downstream side of the joining portion 28 in the forward pipe 17.

  Incidentally, a radiator cap 73 having an air vent valve 72 is provided on the upper portion of the air separator 8. The radiator cap 73 is provided with a pipe 74 through which surplus antifreeze in the air separator 8 flows. The piping 74 is inserted inside the expansion tank 70 provided next to the air separator 8. The expansion tank 70 absorbs expansion and contraction due to a temperature change of the antifreeze liquid circulating through the pipes of the hot water supply apparatuses 2 to 4. Thereby, the antifreeze liquid which the snow melting apparatus 1 hold | maintains can be adjusted to predetermined amount. An antifreeze liquid supply port 75 for supplying antifreeze liquid into the expansion tank 70 and a water level electrode 76 for detecting the water level in the tank are provided at the upper part of the expansion tank 70. An overflow water discharge pipe 78 is provided at the upper part of the side surface of the expansion tank 70 for discharging the antifreeze liquid overflowing from the tank to the outside.

  Next, the electrical configuration of the snow melting device 1 will be described with reference to FIG. The snow melting device 1 includes a control device 5 in a housing 2 </ b> A (see FIG. 1) of the hot water supply device 2. The control device 5 includes a CPU 101 that controls the snow melting device 1. A ROM 102, a RAM 103, and an EEPROM 104 are connected to the CPU 101. The ROM 102 is a non-volatile storage element that stores various programs such as a snow melting operation control program, initial values of various data, and the like. The RAM 103 is a readable and writable volatile storage element that temporarily stores a running program and stores various data. The EEPROM 104 is a nonvolatile storage element that stores counters, parameters, and the like. Although not shown, the control device 5 is provided with an oscillator that supplies a clock to the CPU 101. The control device 5 includes a battery 20 as a power source.

  The CPU 101 includes a gas proportional valve drive circuit 52A, a magnet drive circuit 51A, a thermocouple circuit 115, a frame rod circuit 116, an igniter circuit 117, an abnormal lamp drive circuit 37A, and an input / output (I / O) interface. 121 are connected to each other. A gas proportional valve 52 is connected to the gas proportional valve drive circuit 52A. A gas electromagnetic valve 51 is connected to the magnet drive circuit 51A. A thermocouple 105 is connected to the thermocouple circuit 115. The frame rod 106 is connected to the frame rod circuit 116. An igniter 107 is connected to the igniter circuit 117. An abnormal lamp 37 is connected to the abnormal lamp drive circuit 37A. A safety circuit 114 driven by detection signals output from the thermocouple circuit 115 and the frame rod circuit 116 is connected to the magnet drive circuit 51A.

  The input / output interface 121 includes a hot water supply device side pump drive circuit 31A, a heat radiation side pump drive circuit 32A, a forward temperature thermistor (TH) 58, a return temperature thermistor (TH) 55, a flow rate sensor 56, and a road surface temperature sensor. 35, a snowfall sensor 38, and a remote controller 36 are connected to each other. The hot water supply side pump 31 is connected to the hot water supply side pump drive circuit 31A. A heat radiation side pump 32 is connected to the heat radiation side pump drive circuit 32A.

  Next, the antifreeze will be described. The antifreeze used in this embodiment is a general one mainly composed of glycols such as ethylene glycol and propylene glycol. The viscosity resistance of the antifreeze increases as the temperature of the antifreeze decreases. In the present embodiment, the viscosity resistance of the antifreeze liquid is controlled by maintaining the temperature of the antifreeze liquid within a predetermined temperature range.

  Next, regarding the antifreeze liquid, the ignition temperature for igniting the burner 50 and the fire extinguishing temperature for extinguishing the fire will be described. In the snow melting operation control process of the snow melting device 1 described later, the “ignition temperature” and the “fire extinguishing temperature” of the antifreeze liquid are set in advance. The fire extinguishing temperature is an upper limit value of the temperature at which the antifreeze liquid may boil inside the inner trunk in the housing when the antifreeze liquid is heated and passed through the heat exchanger. For example, when the boiling temperature of the antifreeze liquid is 85 ° C., the fire extinguishing temperature is set to 45 ° C. The ignition temperature is set to a lower temperature (for example, 35 ° C., which is 10 ° C. lower than 45 ° C.). The fire extinguishing temperature can be changed, for example, within a range of 20 to 60 ° C. Therefore, if the return temperature of the antifreeze liquid is equal to or lower than the ignition temperature, the burner 50 is ignited, and if it exceeds the ignition temperature, it is not necessary to ignite the burner 50. On the other hand, if the return temperature is equal to or higher than the extinguishing temperature, the burner 50 is extinguished, and if it is lower than the extinguishing temperature, the burner 50 is not extinguished.

  Next, the operation mode of the snow melting device 1 will be described. In the present embodiment, there are three operation modes: an automatic operation mode, a first heat insulation operation mode, and a second heat insulation operation mode. The user selects any one of these operation modes with the remote controller 36. The operation mode selection information acquired by the remote controller 36 is stored in the RAM 103. When the automatic operation mode is selected, the snow melting operation is executed when it is snowing and the road surface temperature is equal to or lower than a first reference temperature (for example, 8 ° C.). The purpose is to prevent snow accumulation, for example, in general facilities. When the first heat retention operation mode is selected, the snow melting operation is executed when the road surface temperature is lower than the second reference temperature (for example, 1 ° C.) during snowfall or without snowfall. For the purpose of preventing snow accumulation and preventing road surface freezing, for example, it is used in facilities such as hospitals and slopes where freezing is not allowed.

  Further, when the second heat insulation operation mode is selected, the snow melting operation is executed during the snowfall or when the road surface temperature is lower than the second reference temperature (for example, 1 ° C.) within 24 hours after the snowfall disappears. In other words, there is a high possibility that it will resume for a while after it has snowed. Therefore, the road surface temperature is checked within 24 hours after the end of snowfall, and snow melting operation is executed in a predetermined case. If no snowfall continues after 24 hours from the end of snowfall, the possibility of resuming snowfall is low, so the snow melting operation is stopped in order to reduce the running cost of the snow melting apparatus 1. The user can reduce the running cost (for example, the amount of gas, the amount of power, etc.) of the snow melting device 1 by appropriately selecting these operation modes.

  Next, the snow melting operation control process executed by the CPU 101 will be described with reference to the flowchart of FIG. When the power of the snow melting device 1 is turned on, this process is called and executed by the “snow melting operation control program” stored in the ROM 102 (see FIG. 2).

  First, an operation start check process is executed (S10). In the operation start check process, whether or not to start the snow melting operation is checked according to each operation mode. As shown in the flowchart of FIG. 4, it is first determined whether or not the automatic operation mode is selected based on the operation mode selection information stored in the RAM 103 (S41). When the automatic operation mode is selected (S41: YES), an automatic operation start check process is executed (S42). When the first heat insulation operation mode or the second heat insulation operation mode is selected (S41: NO), the same heat insulation operation start check process is executed (S43).

  The automatic operation start check process will be described with reference to the flowchart of FIG. First, an automatic operation lamp (not shown) provided on the remote controller 36 is turned on (S46). Next, it is determined whether or not the snow sensor 38 has detected snow (S47). While no snowfall is detected (S47: NO), the process returns to S47 and enters a standby state. When snowfall is detected (S47: YES), it is subsequently determined whether or not the road surface temperature detected by the road surface temperature sensor 35 is 8 ° C. or less (S48). In addition, this 1st reference temperature is not limited to 8 degreeC, It can change suitably.

  When the road surface temperature exceeds 8 ° C. (S48: NO), the snow melts and does not accumulate even if it is snowing. Therefore, the snowfall and the road surface temperature are continuously monitored (S47, S48). When the road surface temperature becomes 8 ° C. or lower (S48: YES), the road surface temperature starts to fall and snow may accumulate. Therefore, the process proceeds to S11 in FIG. 3, and the hot water supply device side pump 31 and the heat radiation side pump 32 are At the same time (S11), the snow melting operation is started.

  Next, the heat insulation operation start check process will be described with reference to the flowchart of FIG. First, based on the operation mode selection information stored in the RAM 103, it is determined whether or not the first heat retention operation mode is selected (S51). When the first heat retention operation mode is selected (S51: YES), a first heat retention operation lamp (not shown) provided on the remote controller 36 is turned on (S52). When the second heat insulation operation mode is selected (S51: NO), a second heat insulation operation lamp (not shown) provided on the remote controller 36 is turned on (S53).

  Next, it is determined whether or not the snowfall sensor 38 has detected snowfall (S54). When snowfall is detected (S54: YES), it is subsequently determined whether or not the road surface temperature detected by the road surface temperature sensor 35 is 8 ° C. or less (S55).

  When the road surface temperature exceeds 8 ° C. (S55: NO), even if it is snowing, the snow melts and does not accumulate, so the snowfall and the road surface temperature are continuously monitored (S54, S55). When the road surface temperature becomes 8 ° C. or lower (S54: YES), there is a possibility that the road surface temperature starts to fall and snow is accumulated. Therefore, the process proceeds to S11 in FIG. At the same time (S11), the snow melting operation is started.

  On the other hand, when the snowfall sensor 38 does not detect snowfall (S54: NO), it is subsequently determined whether or not the road surface temperature detected by the road surface temperature sensor 35 is 1 ° C. or less (S56). If the road surface temperature is not 1 ° C. or lower (S56: NO), there is no risk of road surface freezing and the necessity of executing snow melting operation is low, so the presence or absence of snowfall and the road surface temperature are continuously monitored (S54, S56). If the road surface temperature is 1 ° C. or lower (S56: YES), there is a risk of road surface freezing even if there is no snow, so the process proceeds to S11 in FIG. 3 and the hot water supply side pump 31 and the heat dissipation side pump 32 are turned on simultaneously. Then (S11), the snow melting operation is started. The second reference temperature is not limited to 1 ° C. and can be changed as appropriate.

  Then, returning to the main flow of FIG. 3, when the snow melting operation is started, the antifreeze liquid starts to circulate in the snow melting device 1. Next, the flow rate sensor 56 detects the return flow rate of the antifreeze liquid passing through the pipe 46 in the hot water supply device 2, and determines whether or not the detected return flow rate is equal to or higher than the normal circulation flow rate (S12). The “circulation normal flow rate” is, for example, a minimum flow rate (for example, 2.0 L / min) at which the hot water supply side pump 31 and the heat dissipation side pump 32 can operate without biting air.

  Here, when the return flow rate is less than the normal circulation flow rate (S12: NO), it is a circulation abnormality, so the failure of the hot water supply side pump 31 and the heat radiation side pump 32 or the first return pipe 7, the air separator 8, The breakage of the return pipe 9, the third return pipe 10, the branch pipes 11 to 16, the forward pipe 17, the heating pipe 19, etc. can be considered. In particular, when the hot water supply device side pump 31 fails, the flow rate of the antifreeze circulating in the pipe 46 is insufficient, and the heat exchanger may be damaged by emptying. Therefore, both the hot water supply apparatus side pump 31 and the heat radiation side pump 32 are forcibly stopped (S27), the abnormal lamp 37 is turned on (S28), and the process ends. Thereby, since circulation abnormality can be alert | reported promptly, while ensuring the safety of the snow melting apparatus 1, it can respond to the malfunction of the snow melting apparatus 1 rapidly.

  On the other hand, when the return flow rate is equal to or higher than the normal circulation flow rate (S12: YES), at least the hot water supply device side pump 31 and the heat radiation side pump 32 are operating normally, and the antifreeze circulates normally in the snow melting device 1.

  Next, it is determined whether or not the return temperature of the antifreeze liquid detected by the return temperature thermistor 55 in the hot water supply device 2 is equal to or lower than the ignition temperature (S14). If the return temperature exceeds the ignition temperature (S14: NO), the burner 50 is not ignited and the process returns to S14. Until the return temperature becomes equal to or lower than the ignition temperature, the antifreeze circulates in the snow melting device 1 without the burner 50 being ignited. Therefore, the temperature of the antifreeze liquid gradually decreases.

  And when return temperature becomes below ignition temperature (S14: YES), each burner 50 of the hot-water supply apparatuses 2-4 is each ignited (S15). Specifically, in each of the hot water supply apparatuses 2 to 4, the gas electromagnetic valve 51 is opened and the gas proportional valve 52 is operated to perform a slow ignition operation, so that gas is supplied to each burner 50. At the same time, since the igniter 107 is continuously discharged, each burner 50 is ignited.

  Next, it is determined whether or not the return flow rate of the antifreeze liquid detected by the flow rate sensor 56 is the target circulation flow rate (S16). In the present embodiment, the target circulation flow rate is set to 12 L / min. When the target circulation flow rate is set to 12 L / min, the antifreeze liquid is supplied to each of the hot water supply apparatuses 2 to 4 at a flow rate of 12 L / min. That is, in order to supply the antifreeze liquid to each of the water heaters 2 to 4 at a flow rate of 12 L / min, the hot water supply apparatus side pump 31 supplies the antifreeze liquid at a flow rate of 36 L / min (= 12 L / min × 3). What is necessary is just to supply to the return pipe | tube 10.

  Here, since the viscosity resistance of the antifreeze liquid fluctuates due to temperature changes, the flow rate of the antifreeze liquid also fluctuates when the hot water supply side pump 31 is controlled with the same ability. Furthermore, if the snow melting area varies from site to site, the flow resistance of the heating pipe 19 changes, so the flow rate of the antifreeze further varies. Therefore, the capacity of the hot water supply apparatus side pump 31 is controlled so that the return flow rate of the antifreeze liquid detected by the flow sensor 56 is 12 L / min.

  For example, when the return flow rate of the antifreeze liquid detected by the flow sensor 56 is not the target circulation flow rate (S16: NO), the capacity of the hot water supply apparatus side pump 31 is adjusted so that the return flow rate becomes the target circulation flow rate ( S29). Then, returning to S16, when the return flow rate of the antifreeze becomes the target circulation flow rate (S16: YES), the combustion proportional temperature control is started (S17).

  In the combustion proportional temperature control, for example, when there is a difference between the antifreeze forward temperature detected by the forward temperature thermistor 58 and the set temperature, the opening of the gas proportional valve 52 is adjusted and the casings 2A to 4A. The heating power is adjusted by adjusting the rotational speed of a fan (not shown) provided inside, and the antifreeze liquid is adjusted to the set temperature.

  Subsequently, it is determined whether or not the temperature difference between the antifreeze liquid return temperature and the return temperature is within a predetermined range (S18). The temperature difference between the antifreeze liquid return temperature and the return temperature is adjusted to be within a range of 13 to 17 ° C., for example. When the temperature difference between the forward temperature and the return temperature exceeds the predetermined range (S18: NO), the capacity of the heat radiation side pump 32 is adjusted (S30). On the upstream side of the heating pipe 19, the temperature of the antifreeze liquid is high, so that the snow melts, but on the downstream side, the temperature of the antifreeze liquid is too low, so the heat load per unit area is reduced and unmelted is generated. That is, a difference in melting method occurs in the snow melting target region 6, and so-called “snow melting unevenness” occurs.

  Furthermore, since the return temperature of the antifreeze is too low, the viscous resistance increases. When the viscous resistance increases, it becomes difficult for the antifreeze liquid to flow. Therefore, the entire circulation flow rate of the snow melting device 1 is less than a specified flow rate (for example, 120 L / min). In this case, the pumping capacity of the heat radiation side pump 32 is increased (S30). Thereby, the circulation flow rate of the antifreeze liquid can be returned to the specified flow rate. Then, since the temperature difference between the going temperature and the return temperature is gradually reduced, the snow melting unevenness is eliminated by being within the range of 13 to 17 ° C., and the snow accumulation in the snow melting target region 6 can be melted uniformly.

  On the other hand, when the temperature difference between the return temperature and the return temperature is lower than the predetermined range (S18: NO), there is almost no difference between the return temperature and the return temperature. Is likely to have already melted. When the snow is melted, the antifreeze liquid is heated by the water heaters 2 to 4 even though the heat is not taken away much from the snow, so that the return temperature of the antifreeze liquid tends to gradually increase. As the return temperature of the antifreeze increases, the viscosity resistance of the antifreeze decreases. If the viscous resistance decreases, the antifreeze liquid flows too much. Therefore, it is considered that the entire circulation flow rate of the snow melting device 1 is higher than a specified flow rate (for example, 120 L / min). In this case, the pumping capacity of the heat radiation side pump 32 is reduced (S30). Thereby, the circulation flow rate of the antifreeze liquid can be returned to the specified flow rate. Then, the temperature difference between the return temperature and the return temperature gradually increases and falls within the range of 13 to 17 ° C., so that it is possible to prevent the antifreeze liquid from flowing too much into the heating pipe 19. That is, since the antifreeze does not flow too much, waste of power of the heat radiation side pump 32 can be reduced.

  Then, returning to S18, when the temperature difference between the return temperature and the return temperature falls within a predetermined range (S18: YES), it is determined whether or not the return flow rate detected by the flow sensor 56 is equal to or less than the fire extinguishing flow rate. (S19). The fire extinguishing flow rate is lower than the normal circulation flow rate, and is set to the minimum flow rate (for example, 1.5 L / min) required for the heated antifreeze liquid to circulate in the snow melting device 1 after the burner 50 is ignited. Yes. When the return flow rate is equal to or less than the fire extinguishing flow rate (S19: YES), the burner 50 is ignited and the antifreeze is heated, but the return flow rate does not increase. The failure of the side pump 32 or the breakage of the first return pipe 7, the air separator 8, the second return pipe 9, the third return pipe 10, the branch pipes 11 to 16, the forward pipe 17, the heating pipe 19, etc. . Therefore, the burner 50 is forcibly extinguished (S31), both the hot water supply side pump 31 and the heat dissipation side pump 32 are forcibly stopped (S32), the abnormal lamp 37 is turned on (S33), and the process is completed. . Thereby, since circulation abnormality can be alert | reported promptly, while ensuring the safety of the snow melting apparatus 1, it can respond to the malfunction of the snow melting apparatus 1 rapidly.

  On the other hand, when the return flow rate exceeds the fire extinguishing flow rate (S19: NO), there is a possibility that the viscosity resistance of the antifreeze liquid is reduced and the return flow rate of the antifreeze liquid is increasing. If the viscosity resistance of the antifreeze liquid is reduced, the return temperature of the antifreeze liquid may be high. Therefore, it is determined whether or not the return temperature detected by the return temperature thermistor 55 is equal to or higher than a preset fire extinguishing temperature (S21). When the return temperature is equal to or higher than the fire extinguishing temperature (S21: YES), if the heating by the burner 50 is continued as it is, there is a high possibility of boiling inside the inner drum in the casing. Is extinguished (S35), the process returns to S14, and the antifreeze circulates in the snow melting apparatus 1 with the burner 50 extinguished until the temperature drops below the ignition temperature. After this, the above process is repeated. On the other hand, when the return temperature is lower than the fire extinguishing temperature (S21: NO), an operation continuation check process is executed (S22). In the operation continuation check process, it is checked whether or not the snow melting operation is continued according to each operation mode.

  As shown in the flowchart of FIG. 7, first, based on the operation mode selection information stored in the RAM 103, whether the automatic operation mode is selected, the first heat insulation operation mode is selected, or the second heat insulation operation mode is selected. It is determined whether it is selected (S61, S62). When the automatic operation mode is selected (S61: YES), the automatic operation continuation check process is executed (S63). When the first heat insulation operation mode is selected (S61: NO, S62: YES), the first heat insulation operation continuation check process is executed (S64). When the second heat insulation operation mode is selected (S61: NO, S62: NO), the second heat insulation operation continuation check process is executed (S65).

  First, the automatic driving continuation check process will be described with reference to the flowchart of FIG. First, it is determined whether or not the snow sensor 38 has detected snow (S71). When snowfall is detected (S71: YES), it is determined whether the road surface temperature is 8 ° C. or less (S72). If the road surface temperature is 8 ° C. or lower (S72: YES), it is highly necessary to continue the snow melting operation as it is. Accordingly, the process returns to S16 in FIG. 3, the return flow rate of the antifreeze liquid detected by the flow rate sensor 56 is checked for the target circulation flow rate, and the snow melting operation is continued.

  On the other hand, when no snowfall is detected (S71: NO), the hot water supply device side pump 31 and the heat dissipation side pump 32 are turned off, and the burners 50 of the respective hot water supply devices 2, 3, and 4 are extinguished, and snow melting is performed. The operation is stopped (S73). And it returns to S10 of FIG. 3, an operation start check process is performed again, and it will be in a standby state until the next snow melting operation is performed.

  Further, even if snowfall is detected (S71: YES), if the road surface temperature exceeds 8 ° C. (S72: NO), the snow accumulation in the snow melting target region 6 melts, so the hot water supply side pump 31 and the heat dissipation side pump 32 is turned off, the burner 50 is extinguished, and the snow melting operation is stopped (S73). And it returns to S10 of FIG. 3, an operation start check process is performed again, and it will be in a standby state until the next snow melting operation is performed.

  Next, the first heat insulation operation continuation check process will be described with reference to the flowchart of FIG. First, it is determined whether or not the snow sensor 38 has detected snow (S81). When snowfall is detected (S81: YES), it is determined whether the road surface temperature, which is the first reference temperature, is 8 ° C. or less (S82). If the road surface temperature is 8 ° C. or lower (S82: YES), there is a high possibility of snow accumulation. Therefore, the process returns to S16 in FIG. 3 to check whether the return flow rate of the antifreeze liquid detected by the flow rate sensor 56 is the target circulation flow rate, and the snow melting operation is continued.

  On the other hand, if no snowfall is detected (S81: NO), it is determined whether the road surface temperature is equal to or higher than 1 ° C., which is the second reference temperature (S85). When the road surface temperature is less than 1 ° C. (S85: NO), the possibility of road surface freezing is high. Therefore, the process returns to S16 in FIG. 3 to check whether the return flow rate of the antifreeze liquid detected by the flow rate sensor 56 is the target circulation flow rate, and the snow melting operation is continued. Thereby, road surface freezing can be prevented. On the other hand, when the road surface temperature is 1 ° C. or higher (S85: YES), the possibility of road surface freezing is low. If the snow melting operation is continued as it is, gas and power are consumed wastefully. Therefore, the hot water supply device side pump 31 and the heat dissipation side pump 32 are turned off, the burner 50 is extinguished, and the snow melting operation is stopped (S86).

  Next, the second heat insulation operation continuation check process will be described with reference to the flowchart of FIG. First, it is determined whether or not the snowfall sensor 38 has detected snowfall (S91). When snowfall is detected (S91: YES), it is determined whether the road surface temperature is equal to or lower than 8 ° C., which is the first reference temperature (S92). If the road surface temperature is 8 ° C. or lower (S92: YES), it is highly necessary to continue the snow melting operation as it is. Accordingly, the process returns to S16 in FIG. 3, the return flow rate of the antifreeze liquid detected by the flow rate sensor 56 is checked for the target circulation flow rate, and the snow melting operation is continued.

  On the other hand, when no snowfall is detected (S91: NO), a timer (not shown) is started in order to measure the elapsed time since the snowfall disappeared (S93). The timer counts pulses generated by the internal clock and measures the elapsed time. Then, it is determined whether or not 24 hours have elapsed since the time when there was no snowfall (S94). If 24 hours have not yet elapsed (S94: NO), it is then determined whether the road surface temperature is equal to or higher than 1 ° C., which is the second reference temperature (S95). When the road surface temperature is less than 1 ° C. (S95: NO), the possibility of road surface freezing is high. Therefore, the process returns to S16 in FIG. 3 to check whether the return flow rate of the antifreeze liquid detected by the flow rate sensor 56 is the target circulation flow rate, and the snow melting operation is continued. Thereby, road surface freezing can be prevented.

  On the other hand, when the road surface temperature is 1 ° C. or higher (S95: YES), the possibility of road surface freezing is low. If the snow melting operation is continued as it is, gas and power are consumed wastefully. Therefore, the hot water supply device side pump 31 and the heat dissipation side pump 32 are turned off, the burner 50 is extinguished, and the snow melting operation is stopped (S96). Further, the elapsed time T is cleared (S97), and the process returns to S10 in FIG. Then, the operation start check process is executed again, and a standby state is entered until the next snow melting operation is executed.

  And if 24 hours have passed since the time when there was no snowfall (S94: YES), the snow melting operation was continued in spite of no snowfall. End up. Therefore, the hot water supply device side pump 31 and the heat dissipation side pump 32 are turned off, the burner 50 is extinguished, and the snow melting operation is stopped (S96). Further, the elapsed time T is cleared (S97), and the process returns to S10 in FIG. Then, the operation start check process is executed again, and a standby state is entered until the next snow melting operation is executed.

  As described above, in the snow melting device 1 according to the present embodiment, the operation mode can be selected according to the environment of the installation location. The operation modes include an automatic operation mode, a first heat insulation operation mode, and a second heat insulation operation mode. In the automatic operation mode, the snow melting operation is executed when snowfall is detected and the road surface temperature is lower than the reference temperature. In the first heat retention operation mode, snow melting operation is performed when snowfall is detected or when the road surface temperature is equal to or lower than a reference temperature. In the second heat insulation operation mode, snow melting operation is executed when snowfall is detected or when the road surface temperature becomes equal to or lower than the reference temperature within 24 hours after the end of snowfall. Since these operation modes can be selected as appropriate in the snow melting device 1, the running cost (for example, gas amount, electric energy, etc.) of the snow melting device 1 can be effectively reduced.

  In addition, this invention is not limited to the said embodiment, A various change is possible. For example, in the above embodiment, assuming that it is used in the mid-winter period of a warm area with little road surface freezing, the snow melting operation is stopped when 24 hours have elapsed since the time when snow has disappeared in the second heat insulation operation mode. In addition, the running cost is reduced. In addition to such a method, for example, when there is no snowfall, the conditions for continuing the snow melting operation may be tightened according to the elapsed time since the snowfall disappeared. Specifically, the second reference temperature, which is a reference for continuing or stopping the snow melting operation, is lowered according to the elapsed time from when the snowfall disappeared. Even with such a method, the execution time of the snow melting operation can be effectively shortened.

  Therefore, a first modification in which the second heat insulation operation continuation check process of the above embodiment is modified will be described with reference to the flowchart of FIG. Since S91 and 92 in FIG. 11 are the same processing as S91 and 92 in FIG. 10, description thereof will be omitted and different steps will be mainly described.

  First, when snowfall is not detected by the snowfall sensor 38 (S91: NO), a timer (not shown) is started in order to measure the elapsed time from when the snowfall disappeared (S103). Next, a second reference temperature is calculated (S104). The second reference temperature is a conditional temperature for continuing or stopping the snow melting operation.

Here, a method for calculating the second reference temperature will be described. The second reference temperature is defined as K, the initial temperature is defined as K ₀ , the elapsed time from when snow has disappeared is defined as T, and the coefficient is defined as α (an integer greater than or equal to 0). The initial temperature K ₀ is the first second reference temperature K when there is no snowfall (T = 0), and can be set freely. When defined in this way, it is calculated as K = K ₀ −αT (° C.) (S104). Thereby, the second reference temperature has a property of becoming lower as the elapsed time T becomes longer. For example, when K ₀ = 1 ° C., K = 1−αT (° C.).

  Next, it is determined whether or not the road surface temperature detected by the road surface temperature sensor 35 is 1−αT (° C.) or more (S105). When the road surface temperature is less than 1−αT (° C.) (S105: NO), the road surface temperature is considerably cooled. Therefore, the process returns to S16 in FIG. 3 to check whether the return flow rate of the antifreeze liquid detected by the flow rate sensor 56 is the target circulation flow rate, and the snow melting operation is continued. Thereby, road surface freezing can be prevented.

  On the other hand, when the road surface temperature is 1−αT (° C.) or higher (S105: YES), the possibility of road surface freezing is low. If the snow melting operation is continued as it is, gas and power are consumed wastefully. Therefore, the hot water supply device side pump 31 and the heat dissipation side pump 32 are turned off, the burner 50 is extinguished, and the snow melting operation is stopped (S106). Further, the elapsed time T is cleared (S107), and the process returns to S10 in FIG. Then, the operation start check process is executed again, and a standby state is entered until the next snow melting operation is executed.

  Also in such a 1st modification, the effect similar to the 2nd heat insulation driving | operation continuation check process of the said embodiment can be acquired. Since the snow melting operation time can be effectively reduced, the running cost of the snow melting device 1 can be reduced, and the gas amount and the power consumption can be surely saved.

Next, a second modification of the second heat insulation operation continuation check process of the above embodiment will be described. The second modification is a further modification of the first modification. In the first modification, the second reference temperature is calculated as K ₀ −αT (° C.), and α is a fixed value. In the second modification, the coefficient α can be changed according to the snowfall prediction of the user.

  Here, the snowfall prediction is a multistage classification of the possibility of snowfall. For example, the snowfall prediction can be divided into three stages of “strong”, “medium”, and “weak” in descending order of possibility of snowfall. A table 1041 (see FIG. 12) associated with the coefficient α is stored in the EEPROM 104 in advance in accordance with these three snowfall predictions. In the table 1041 shown in FIG. 12, coefficients α = “0”, “2”, and “4” are stored in association with snowfall predictions “strong”, “medium”, and “weak”. The snowfall prediction “strong”, “medium”, and “weak” can be selected and input by the user with the remote controller 36, for example. Input information of the remote controller 36 is stored in the RAM 103 or the like as “external information”.

  As shown in FIG. 13, the process of the second modification is almost the same as the process of FIG. 11, and the processes of S88, S89, and S90 are executed before S91. First, external information relating to snowfall prediction is acquired (S88). As described above, here, for example, the input information of the remote controller 36 is acquired as “external information”. Based on the acquired input information, the snowfall prediction selected by the user through the remote controller 36 is determined (S89). Then, the coefficient α corresponding to the determined snowfall prediction is determined with reference to the table 1041 stored in the EEPROM 104 (S90).

Thereafter, processing is executed as in the first modification (S91, S92, S101). When there is no snowfall (S91: NO), the timer is started (S92), and the second reference temperature K = K ₀ −αT (° C.) is calculated using the coefficient α determined in S90. (S104). Here, as shown in the table 1041, the coefficient α is larger in the snowfall prediction “weak” than in the “strong”. Therefore, if the snowfall prediction is “weak”, the second reference temperature is set low. On the contrary, the coefficient α is smaller for the snowfall prediction “strong” than for “weak”. Therefore, if the snowfall prediction is “strong”, the second reference temperature is set high.

  For example, if the user determines that “the possibility of snowfall is high” from the weather forecasts provided by various media, the surrounding conditions, etc., it is desired to continue snow melting operation as much as possible in preparation for snowfall even in the absence of snowfall. Therefore, when the user inputs snowfall prediction “strong” with the remote controller 36, the second reference temperature is set at a relatively high temperature. Since the snowfall prediction is “strong”, the outside air temperature is low, and the road surface temperature is lower than the second reference temperature even when there is no snowfall. In this case (S105: NO), the snow melting operation is continued (to S16 in FIG. 3).

  On the contrary, if the user determines that “the possibility of snowfall is low”, the snow melting operation should be stopped as much as possible in the absence of snowfall to save the amount of gas and electric power. Therefore, when the user inputs the snowfall prediction “weak” with the remote controller 36, the second reference temperature is set at a relatively low temperature. Since the snowfall prediction is “weak”, the outside air temperature is higher than that during snowfall, and the road surface temperature is equal to or higher than the second reference temperature. In this case (S105: YES), the snow melting operation is stopped (S104). Accordingly, it is possible to effectively save the amount of gas and the amount of power consumed in the snow melting operation.

  Thus, in the second modification, the slope (degree) at which the second reference temperature changes can be changed by changing the coefficient α in accordance with the snowfall prediction. That is, the lower the snowfall prediction is, the larger the coefficient α is, so the degree of lowering the second reference temperature is greater. The higher the snowfall prediction is, the smaller the coefficient α becomes, so the degree of lowering the second reference temperature becomes smaller. Since the second reference temperature changes according to the snowfall prediction input by the user, it is possible to effectively save the amount of gas and electric power consumed in the snow melting operation while responding to climate change. These first modified example or second modified example may be selectable as “third heat retaining operation mode” instead of the second heat retaining operation mode of the above embodiment.

  Needless to say, the present invention can be variously modified in addition to the first and second modified examples described above. For example, although the snow melting apparatus 1 which has a structure shown in FIG. 1 was demonstrated as an example as a structure of the snow melting apparatus which implements this invention, it is not limited to the thing of this structure. What is necessary is just to melt the snow in the snow melting target region by circulating the antifreeze liquid heated by the hot water supply device to the heating pipe by a pump.

In the first modification, the calculation is performed as the second reference temperature K = K ₀ −αT (° C.). However, the second reference temperature is not limited to this calculation formula, and at least as the elapsed time T becomes longer. What is necessary is just to make K low. For example, a table in which the second reference temperature is associated with a plurality of snowfall predictions may be stored in advance, and the second reference temperature corresponding to the input snowfall prediction may be determined from the table.

  In the second modified example, the snowfall prediction is divided into three stages of “strong”, “medium”, and “weak”, but it may be further divided into multiple stages. Further, although the snowfall prediction is input by the remote controller 36, for example, the snowfall prediction information provided by the external server is acquired via the network (Internet), and the coefficient α is determined based on the acquired snowfall prediction information. You may make it do. Further, measurement values of a barometer, a hygrometer, an outside air temperature sensor, and the like may be acquired as “external information”, and snowfall prediction may be determined by itself based on the external information. Further, in order to determine the snowfall prediction, such external information may be acquired from an external server via a network (Internet).

  In the above description, the remote controller 36 corresponds to the “mode selection unit” of the present invention, and the CPU 101 that executes the processes of S88 and S89 in FIG. 13 corresponds to the “snowfall prediction determination unit” of the present invention and executes S90. The CPU 101 that corresponds to the “coefficient changing means” of the present invention.

DESCRIPTION OF SYMBOLS 1 Snow melting apparatus 2-4 Hot water supply apparatus 5 Control apparatus 6 Snow melting object area | region 36 Remote control 101 CPU

Claims (4)

In a snow melting device comprising a hot water supply device incorporating a burner that is a heat source, circulating a heat medium supplied from the hot water supply device to a pipe embedded in the snow melting target region, and melting snow in the snow melting target region ,
A snowfall sensor for detecting snowfall in the snowmelt target area;
A road surface temperature sensor for detecting a road surface temperature in the snow melting target area;
A measuring means for measuring an elapsed time from when snow is no longer detected by the snow sensor;
When snow is detected by the snow sensor, or when the road surface temperature detected by the road surface temperature sensor is lower than a reference temperature when no snow is detected by the snow sensor, the snow melting operation by the snow melting device is performed. A first heat insulation operation mode for allowing
Detected by the road surface temperature sensor when snowfall is detected by the snowfall sensor or until the elapsed time measured by the measuring means reaches a predetermined time in a state where no snowfall is detected by the snowfall sensor. A second heat insulation operation mode for permitting a snow melting operation by the snow melting device when the road surface temperature is less than a reference temperature;
A snow melting apparatus comprising mode selection means for selecting one of the first heat insulation operation mode and the second heat insulation operation mode. In a snow melting device comprising a hot water supply device incorporating a burner that is a heat source, circulating a heat medium supplied from the hot water supply device to a pipe embedded in the snow melting target region, and melting snow in the snow melting target region ,
A snowfall sensor for detecting snowfall in the snowmelt target area;
A road surface temperature sensor for detecting a road surface temperature in the snow melting target area;
A measuring means for measuring an elapsed time from when snow is no longer detected by the snow sensor;
When snow is detected by the snow sensor, or when the road surface temperature detected by the road surface temperature sensor is lower than a reference temperature when no snow is detected by the snow sensor, the snow melting operation by the snow melting device is performed. A first heat insulation operation mode for allowing
When snow is detected by the snow sensor, or when the road surface temperature detected by the road surface temperature sensor is lower than a reference temperature when no snow is detected by the snow sensor, the snow melting operation by the snow melting device is performed. And a third heat retention operation mode in which the reference temperature is set lower as the elapsed time becomes longer;
A snow melting device comprising mode selection means for selecting one of the first heat insulation operation mode and the third heat insulation operation mode. Snowfall prediction determining means for determining a snowfall prediction that is a possibility of snowfall in the snowmelt target region based on an external input;
3. The snow melting device according to claim 2, wherein in the third operation mode, the degree of lowering the reference temperature is changed in accordance with the snowfall prediction determined by the snowfall prediction determining unit.   4. The snow melting device according to claim 3, wherein, in the third operation mode, as the snowfall prediction determined by the snowfall prediction determining unit becomes lower, the degree of lowering the reference temperature is increased.

Images