JP6234392B2 - Hot air heater - Google Patents

Description

  The present invention relates to a hot air heater.

  In combustion equipment such as a gas hot air heater, the rotational speed of a combustion fan that supplies combustion air to a burner (combustor) matches the target rotational speed set according to the required amount of combustion of the burner. A method for controlling the supply current to the fan motor is known (see Patent Document 1).

Japanese Patent Laid-Open No. 10-153315

  However, there may be a rotational speed region in which the resolution is low, such as a rotational speed fluctuation corresponding to a current fluctuation is relatively large in the fan motor. In addition, due to individual differences such as a fan motor or a driver that supplies current to the motor (more precisely, a circuit that constitutes the motor), the actual rotational speed may be different even if the supply current to the motor is the same. In these cases, it is difficult to stably control the rotational speed of the combustion fan.

  For example, when the fan motor has a characteristic that the actual rotational speed during the low-speed operation of the combustion fan is larger than the target rotational speed, the amount of air blown out from the inside of the casing of the heater becomes excessive. For this reason, in a situation where the combustion fan is operating at a low speed in accordance with the stop of the combustion operation of the combustor, there is a possibility that a user in the vicinity will feel a cold wind. In addition, the combustion operation of the combustor may be restarted prematurely in response to an early decrease in the temperature detected by the temperature sensor provided in the housing, and the frequency of restarting and stopping the combustor may increase.

  On the other hand, if the fan motor has a characteristic that the actual rotational speed during the low-speed operation of the combustion fan is smaller than the target rotational speed, the amount of air blown out from the inside of the casing of the heater becomes too small. . For this reason, in the situation where the combustion fan is operating at a low speed in response to the combustion operation of the combustor being stopped, the temperature detected by the temperature sensor provided inside the housing does not decrease easily, and the restart of the combustion operation of the combustor is delayed. In addition, there is a possibility that the users in the vicinity may feel uncomfortable.

  Therefore, an object of the present invention is to provide a hot air heater capable of improving the control stability of the rotational speed of the combustion fan even when there are individual differences in the fan motor.

  The present invention provides a casing, a combustor accommodated in the casing, and the casing as hot air by sucking air into the casing and heating the air with combustion heat of the combustor. A blower fan that blows to the outside, a fan motor as a drive source of the blower fan, a rotational speed sensor for detecting the rotational speed of the blower fan, and the rotational speed of the blower fan to each of a plurality of target rotational speeds And a control device that controls a supply current to the fan motor so as to control the fan motor.

  In the hot air heater of the present invention, the control device determines the rotation speed of the blower fan from the plurality of target rotation speeds during the combustion operation of the combustor and the combustion operation stop of the combustor. When the supply current to the fan motor is controlled so as to control each of at least one target rotational speed at the time, the rotational speed of the blower fan detected by the rotational speed sensor is intermediate the target rotational speed. The fan motor as a requirement that a determination means for determining whether or not the rotation speed is included in a target speed range included as a value and that the rotation speed of the blower fan is determined to be out of the target speed range by the determination means Current control means for correcting the supply current to the at least one target rotational speed when the combustion operation of the combustor is stopped Is set to be larger than the width of a plurality of target speed ranges including each of the plurality of target rotational speeds as intermediate values during the combustion operation of the combustor. And

  According to the hot air heater of the present invention, when the rotational speed of the blower fan is controlled to each of a plurality of target rotational speeds during the combustion operation of the combustor and at least one target rotational speed when the combustion operation is stopped, The supply current to the fan motor is corrected on the condition that the actual rotational speed of the fan is out of the target speed range including the target rotational speed as an intermediate value. Thereby, even if there is an individual difference in the fan motor or the like, the actual rotational speed of the blower fan is controlled to be surely included in the target speed range. For this reason, the situation where the air volume blown out from the inside of the casing of the heater to the outside is excessively or too small is surely prevented.

  The target speed range corresponds to a dead zone regarding the correction of the supply current to the fan motor according to the actual rotational speed of the blower fan. The width of the target speed range corresponding to at least one target rotational speed when the combustion operation of the combustor is stopped is such that the rotational speed of the blower fan corresponds to each of the plurality of target rotational speeds during the combustion operation of the combustor. Wider than the width of. For this reason, during low-speed operation of the blower fan (when operating at the target rotational speed when the combustion operation of the combustor is stopped), during high-speed operation (when operating at multiple target rotational speeds during the combustion operation of the combustor) Even if the fan motor has a characteristic that the change in the actual rotational speed with respect to the change in the supply current is larger than that in (), the supply is made by appropriately differentiating the widths of the plurality of dead zones in view of the characteristic. The frequency of correcting the current can be suppressed low. This reliably prevents the actual rotational speed from becoming unstable due to the characteristics of the fan motor not only during high-speed operation of the blower fan but also during low-speed operation.

  Each of the upper limit value and lower limit value of the target speed range may be set variably. For example, the higher the speed or frequency at which the actual rotation speed of the blower fan exceeds the upper limit value of the target speed range (or lower than the lower limit value), the higher the upper limit value (or lower limit value) of the target speed range is corrected. May be. The deviation between the upper limit value and the intermediate value (target rotation speed) of the target speed range and the lower limit value of the target speed range and the deviation between the intermediate values may be the same or different. As described above, the deviation may change by setting one or both of the upper limit value and the lower limit value variably.

  In the hot air heater of the present invention, the current control means has reached a reference time for a continuous or cumulative time when the determination means determines that the rotational speed of the blower fan is out of the target speed range. As a requirement, the supply current to the fan motor is corrected.

  According to the hot air heater of the said structure, the correction frequency of the supply current with respect to a fan motor can be suppressed further lower by presence of a reference time in addition to the said dead zone. As a result, not only during high-speed operation of the blower fan but also during low-speed operation, a situation in which the actual rotational speed becomes unstable due to the characteristics of the fan motor is more reliably prevented.

  It should be noted that the reference time when the actual rotational speed of the blower fan exceeds the upper limit value of the target speed range (first reference time) and the reference when the actual rotational speed of the blower fan falls below the lower limit value of the target speed range Each of the times (second reference times) may be set variably. For example, the first reference time (or the second reference time) is corrected to be shorter or longer as the speed or frequency at which the actual rotation speed of the blower fan exceeds the upper limit value (or falls below the lower limit value) of the target speed range is higher. May be. The first reference time and the second reference time may be the same or different.

  In the hot air heater of the present invention, the reference time for the at least one target rotation speed when the combustion operation of the combustor is stopped is the reference for each of the plurality of target rotation speeds during the combustion operation of the combustor. It is set to be longer than the time.

  According to the warm air heater of the said structure, the reference time when the rotational speed of a ventilation fan is controlled to at least one target rotational speed at the time of the combustion operation stop of a combustor, the rotational speed of a ventilation fan is combustion of a combustor It is set so as to be longer than a reference time when controlled to each of a plurality of target rotational speeds during operation. For this reason, even when the fan motor has such a characteristic that the change in the actual rotation speed with respect to the change in the supply current is larger in the low speed operation of the blower fan than in the high speed operation, in view of the characteristic, as described above. In addition to appropriately differentiating the widths of the plurality of dead zones, it is possible to suppress the frequency of correction of the supply current to be low by appropriately differentiating the plurality of reference times. This reliably prevents the actual rotational speed from becoming unstable due to the characteristics of the fan motor not only during high-speed operation of the blower fan but also during low-speed operation.

The structure explanatory view of the warm air heater as one embodiment of the present invention. Functional explanatory drawing of the warm air heater as one embodiment of the present invention. Explanatory drawing regarding the change aspect of the actual rotational speed of a ventilation fan.

(Constitution)
The hot air heater according to one embodiment of the present invention shown in FIG. 1 is a gas fan heater, and includes a casing 1 (main body case), a duct 2 disposed inside the casing 1, and a blower fan. 3, a gas burner (combustor) 4, a duct 5, a gas supply pipe 6 and a control device 7 are provided.

  The duct 2 constitutes a hot air blowing path, and an intake port 8 for taking in indoor air is opened in the rear surface of the housing 1, and a hot air outlet 9 is opened in the lower front portion of the housing 1. doing. An air filter 10 is detachably attached to the air inlet 8 in order to prevent dust and dirt from flowing into the duct 2. A movable louver 11 for adjusting the degree of opening is attached to the air outlet 9, and a gad motor 12 for driving the movable louver 11 is provided. Further, a room temperature sensor 13 composed of a thermistor is attached to the inside of the duct 2 in the vicinity of the air inlet 8 so as to face the air inlet 8, and the room temperature sensor 13 sends a signal corresponding to the room temperature to the control device 7. Output to.

  The blower fan 3 includes a fan motor 14 (DC motor) whose rotational speed changes in proportion to the energization current, and a rotary blade 15 that is disposed in the duct 2 facing the blowout port 9 and is driven to rotate by the fan motor 14. The indoor air s is sucked into the internal space of the duct 2 from the air inlet 8 by the rotation of the rotary blade 15. Then, the sucked indoor air s is mixed with the combustion exhaust h of the gas burner 4 incorporated in the duct 2, and this is used as warm air m from the outlet 9 to the outside of the casing 1 (the room in which the casing 1 is installed). ). The blower fan 3 is provided with a rotation speed sensor 16 configured by a Hall element or the like that detects the rotation speed. The rotation speed sensor 16 outputs a signal corresponding to the rotation speed of the fan motor 14 to the control device 7. To do.

  In the gas burner 4 incorporated in the duct 2, a combustion plate 18 is arranged in the combustion cylinder 17, and an ignition electrode 19 for igniting a mixture of combustion air and fuel gas is provided downstream of the combustion plate 18. Arranged. The combustion cylinder 17 of the gas burner 4 is disposed in the duct 2, and the combustion exhaust h is discharged from the combustion cylinder 17 into the duct 2. Further, a thermocouple 20 for detecting the presence or absence of a combustion flame is disposed downstream of the combustion plate 18, and this thermocouple 20 generates an electromotive force when exposed to the combustion flame of the gas burner 4. Is output to the control device 7 as the combustion state of the gas burner 4.

  The duct 5 is a passage for supplying room air s (combustion air) and fuel gas to the gas burner 4, communicates with the inside of the combustion cylinder 17 of the gas burner 4, and is defined by the duct 2 to form the inside of the casing 1. And has an air inlet 21 for indoor air s opened at the back of the housing 1. And the nozzle 22 attached to the front-end | tip of the gas supply pipe 6 is provided in the location by the side of the gas burner 4 of the duct 5. As shown in FIG. In this duct 5, the indoor air s is sucked from the intake port 21 by the rotation operation of the blower fan 3, and the sucked indoor air s is mixed with the fuel gas ejected from the nozzle 22 of the gas supply pipe 6. The air-fuel mixture is supplied to the gas burner 4. The air inlet 21 is covered with the air filter 10 together with the air inlet 8 of the duct 2.

  The gas supply pipe 6 is provided with solenoid valves 24 and 25 and an electromagnetic proportional valve 26 in this order from the upstream side. The solenoid valves 24 and 25 are opened by energization, and block the passage of fuel gas when the energization is stopped. The electromagnetic proportional valve 26 is a valve whose opening increases with the magnitude of the energization current, and the energization current is proportional to the amount of gas supplied to the gas burner 4.

  An operation switch 27, a room temperature setting switch 28, and a filter lamp 29 are disposed on the outer surface of the housing 1. The operation switch 27 instructs the control device 7 to start or end the heating operation by the ON / OFF operation. The room temperature setting switch 28 is an operation switch for setting the room temperature. By the predetermined operation, the set temperature T is raised or lowered by a unit temperature (for example, 1 ° C.) to instruct the control device 7. The filter lamp 29 is controlled by the energization control of the control device 7 when the air flow during the rotation operation of the blower fan 3 is reduced to some extent as compared with the normal case, such as when the air filter 10 is clogged. The light is lit, and the user is notified of the necessity of cleaning the air filter 10 by the lighting.

  The control device 7 is configured by a computer (comprising a CPU (arithmetic processing unit), a memory (storage device) such as a ROM and a RAM, and an I / O circuit). The control device 7 includes a combustion control unit 30 and a fan control unit 31.

  The combustion control unit 30 ignites and extinguishes the gas burner 4 and adjusts the amount of combustion (the amount of fuel gas supplied) based on the instruction signals from the operation switch 27 and the room temperature setting switch 28 and the detection signals from the room temperature sensor 13 and the thermocouple 20. Adjustment) and the like, and the combustion control of the gas burner 4 is performed. In this case, in the present embodiment, the combustion control unit 30 sets the combustion amount (fuel gas supply amount) of the gas burner 4 to the 1st to 12th speed (the 12th speed is the maximum combustion) during the combustion operation including the ignition operation of the gas burner 4. (Equivalent to the quantity).

  The fan control unit 31 controls energization of the fan motor 14 based on the instruction signals from the operation switch 27 and the room temperature setting switch 28 and the detection signals from the room temperature sensor 13, the rotation speed sensor 16, and the thermocouple 20. By controlling the rotational speed, the air volume of the blower fan 3 including the combustion air to the gas burner 4 is controlled. Then, during the combustion operation including the ignition operation of the gas burner 4, the fan control unit 31 sets the air volume (rotational speed) of the blower fan 3 to 1 to 12 speed (12 speed is the maximum combustion) corresponding to the combustion amount of the gas burner 4. It is possible to set in 12 stages (corresponding to the maximum rotation speed of the blower fan 3 corresponding to the amount). While the combustion operation of the gas burner 4 is stopped, the fan control unit 31 sets the air volume (rotational speed) of the blower fan 3 to the P2 speed and P3 speed lower than the first speed (the minimum target of the blower fan 3 when the gas burner 4 is stopped). It corresponds to the rotation speed). The combustion amount (fuel gas supply amount) of the gas burner 4 at each speed and the air volume (rotational speed) of the blower fan 3 corresponding thereto are determined in advance. The fan control unit 31 constitutes “determination means” and “current control means” of the present invention.

(function)
The function of the gas fan heater (hot air heater) having the above-described configuration, particularly the function of the fan control unit 31 will be described.

  When the gas burner 4 is in a combustion operation, the supply current to the fan motor 14 is controlled to a set value corresponding to each of the first to twelfth speeds (the twelfth speed is a target rotational speed corresponding to the maximum combustion amount). It is determined whether or not the actual rotational speed R of the blower fan 3 measured based on the output signal of the rotational speed sensor 16 is included in the corresponding target speed range. The supply current to the fan motor 14 is corrected on the condition that the determination result is negative. Specifically, the supply current to the fan motor 14 is reduced on the condition that it is determined that the actual rotational speed R of the blower fan 3 has exceeded the upper limit value of the target range. The supply current to the fan motor 14 is increased on the condition that it is determined that the actual rotational speed R of the blower fan 3 has fallen below the lower limit value of the target range.

  It is determined based on the output signal of the thermocouple 20 whether or not the temperature adjustment operation of the heater, that is, the combustion operation of the gas burner 4 has been stopped (FIG. 2 / STEP02).

  When it is determined that the combustion operation of the gas burner 4 has been stopped (FIG. 2 / STEP02... YES), the supply current to the fan motor 14 changes the rotational speed of the blower fan 3 to the target rotational speed R (P2) corresponding to the P2 speed. It is controlled to a preset value for control (FIG. 2 / STEP 10). When the command signal for the motor driver (microcomputer) constituting the fan control unit 31 is changed in units of bits, the current supplied to the fan motor 14 is changed by the motor driver according to the number of changed bits.

  It is determined using a timer (not shown) whether or not a first set time T (P2) (for example, 5 [s]) has elapsed since the start of P2-speed operation (FIG. 2 / STEP 11). When it is determined that the first set time T (P2) has not elapsed (FIG. 2 / STEP11... NO), the supply current to the fan motor 14 is maintained at the first set value corresponding to the P2 speed (FIG. 2). / STEP 10). When it is determined that the first set time T (P2) has elapsed (FIG. 2 / STEP11... YES), the actual rotational speed R of the blower fan 3 measured based on the output signal of the rotational speed sensor 16 is P2 speed. It is determined whether or not it is included in the first target speed range S1 (see FIG. 3). The first target speed range S1 includes the target rotation speed R (P2) as an intermediate value. The magnitude of the deviation between the intermediate value R (P2) of the first target speed range S1 and each of the upper limit value S1_max and the lower limit value S1_min is the same. The width of the first target speed range S1 is set to be equal to or smaller than the width of the target speed range corresponding to each of the 1st to 12th speeds.

  Specifically, it is determined whether or not the actual rotational speed R of the blower fan 3 exceeds the upper limit value S1_max of the first target speed range S1 (FIG. 2 / STEP 12). When it is determined that the actual rotational speed R of the blower fan 3 is equal to or lower than the upper limit value S1_max of the first target speed range S1 (FIG. 2 / STEP12... NO), the actual rotational speed R of the blower fan 3 is the first target speed range. It is further determined whether or not the lower limit value S1_min of S1 is below (FIG. 2 / STEP 13).

  When it is determined that the actual rotational speed R of the blower fan 3 exceeds the upper limit value S1_max (FIG. 2 / STEP12... YES), the command signal of the fan control unit 31 is reduced by 1 bit (FIG. 2 / STEP18). . Accordingly, the supply current to the fan motor 14 is reduced, and as a result, the actual rotational speed R of the blower fan 3 is reduced. When it is determined that the actual rotational speed R of the blower fan 3 is lower than the lower limit value S1_min (FIG. 2 / STEP13... YES), the command signal of the fan control unit 31 is increased by 1 bit (FIG. 2 / STEP19). . In response to this, the supply current to the fan motor 14 is increased, and as a result, the actual rotational speed R of the blower fan 3 is increased. When there is a command signal from the fan control unit 31, the first set value corresponding to the P2 speed is updated based on the changed command signal, and then stored and held in the storage device constituting the fan control unit 31. May be.

  When it is determined that the actual rotational speed R of the blower fan 3 is equal to or higher than the lower limit value S1_min (FIG. 2 / STEP13... NO), the command signal of the fan control unit 31 is not changed, and the P2 speed operation end condition is It is determined whether it is satisfied (FIG. 2 / STEP 100). Also when the command signal of the fan control unit 31 is changed (see FIG. 2 / STEP 18 and STEP 19), it is determined whether or not the P2 speed operation end condition is satisfied (FIG. 2 / STEP 100). Specifically, it is determined whether or not the duration of the P2 speed operation has reached a first predetermined time (longer than the first set time T (P2)). Alternatively or additionally, it may be determined whether or not the temperature (room temperature) measured based on the output signal of the room temperature sensor 13 has dropped to a predetermined temperature.

  When it is determined that the condition for terminating the P2 speed operation is not satisfied (FIG. 2 / STEP100... NO), the actual rotational speed R of the blower fan 3 is included in the first target speed range S1 corresponding to the P2 speed. The above-described series of processing including the determination of whether or not there is (FIG. 2 / STEP 12, STEP 13, STEP 18, and STEP 19).

  When it is determined that the termination condition for the P2 speed operation is satisfied (FIG. 2 / STEP100... YES), the supply current to the fan motor 14 is set to the target rotation speed R (the rotation speed of the blower fan 3 corresponding to the P3 speed. P2) is controlled to a second set value that is set in advance (FIG. 2 / STEP 20).

  It is determined using a timer (not shown) whether or not a second set time T (P3) (for example, 5 [s]) has elapsed since the start of P3 speed operation (FIG. 2 / STEP 21). The second set time T (P3) may be the same as or different from the first set time T (P2). When it is determined that the second set time T (P3) has not elapsed (FIG. 2 / STEP 21... NO), the supply current to the fan motor 14 is maintained at the second set value corresponding to the P3 speed (FIG. 2). / STEP 20). When it is determined that the second set time T (P3) has passed (FIG. 2 / STEP21... YES), the actual rotational speed R of the blower fan 3 measured based on the output signal of the rotational speed sensor 16 is P3 speed. It is determined whether or not it is included in the second target speed range S2 (see FIG. 3). The magnitude of the deviation between the intermediate value R (P3) of the second target speed range S2 and each of the upper limit value S2_max and the lower limit value S2_min is the same. The width of the second target speed range S2 is set wider than the width of the first target speed range S1. In addition, while the target rotational speed according to each of P2 speed and P3 speed is the same, the width | variety of 2nd target speed range S2 may be set wider than the width | variety of 1st target speed range S1.

  Specifically, it is determined whether or not the actual rotational speed R of the blower fan 3 exceeds the upper limit value S2_max of the second target speed range S2 corresponding to the P3 speed (FIG. 2 / STEP22). When it is determined that the actual rotational speed R of the blower fan 3 is equal to or lower than the upper limit value S2_max (FIG. 2 / STEP22... NO), the actual rotational speed R of the blower fan 3 is equal to the lower limit value S2_min of the second target speed range S2. It is further determined whether it is below (FIG. 2 / STEP 23).

  When it is determined that the actual rotational speed R of the blower fan 3 exceeds the upper limit value S2_max (FIG. 2 / STEP22... YES), the duration Σ1 of the state increases by Δt (the arithmetic processing period of the fan control unit 31). (FIG. 2 / STEP 24). Then, it is determined whether or not the duration time Σ1 has reached the first reference time TH1 (FIG. 2 / STEP 26). When it is determined that the duration Σ1 has reached the first reference time TH1 (FIG. 2 / STEP 26... YES), the command signal of the fan control unit 31 is reduced by 1 bit (FIG. 2 / STEP 28). Accordingly, the supply current to the fan motor 14 is reduced, and as a result, the actual rotational speed R of the blower fan 3 is reduced.

  For example, as indicated by the one-dot chain line in FIG. 3, after the P3 speed operation is started after time t0, the actual rotational speed R of the blower fan 3 is the upper limit value S2_max of the second target speed range S2 at time t1. Think about a case that exceeds. In this case, the current supplied to the fan motor 14 after time t1 + TH1 when the duration of the state where the actual rotational speed R of the blower fan 3 exceeds the upper limit value S2_max of the second target speed range S2 has reached the first reference time TH1. Is controlled so that the actual rotational speed R of the blower fan 3 falls and falls within the second target speed range S2.

  When it is determined that the actual rotational speed R of the blower fan 3 is lower than the lower limit value S2_min (FIG. 2 / STEP23... YES), the duration Σ2 of the state is increased by Δt (FIG. 2 / STEP25). Then, it is determined whether or not the duration time Σ2 has reached the second reference time TH2 (FIG. 2 / STEP 27). The second reference time TH2 may be the same as or different from the first reference time TH1. When it is determined that the duration Σ2 has reached the second reference time TH2 (FIG. 2 / STEP 27... YES), the command signal of the fan control unit 31 is increased by 1 bit (FIG. 2 / STEP 29). In response to this, the supply current to the fan motor 14 is increased, and as a result, the actual rotational speed R of the blower fan 3 is increased.

  For example, as indicated by a two-dot chain line in FIG. 3, after the P3 speed operation is started after time t0, the actual rotational speed R of the blower fan 3 is the lower limit value of the second target speed range S2 at time t2. Consider a case where it falls below S2_min. In this case, the current supplied to the fan motor 14 after time t2 + TH2 when the duration of the state where the actual rotational speed R of the blower fan 3 exceeds the lower limit value S2_min of the second target speed range S2 has reached the second reference time TH2. Is controlled so that the actual rotational speed R of the blower fan 3 increases and falls within the second target speed range S2.

  When there is a command signal of the fan control unit 31, the second set value corresponding to the P3 speed is updated based on the command signal after the change, and is then stored and held in the storage device constituting the fan control unit 31. May be.

  When it is determined that the actual rotational speed R of the blower fan 3 is equal to or higher than the lower limit value S2_min (FIG. 2 / STEP23... NO), the command signal of the fan control unit 31 is not changed, and the P3 speed operation end condition is It is determined whether it is satisfied (FIG. 2 / STEP 200). When it is determined that each of the durations Σ1 and Σ2 has not reached each of the reference times TH1 and TH2 (FIG. 2 / STEP26... NO, STEP27... NO), the command signal of the fan control unit 31 is changed. Also in the case (see STEP 28 and STEP 29 in FIG. 2), it is determined whether or not the condition for terminating the P3 speed operation is satisfied (FIG. 2 / STEP 200). Specifically, it is determined whether the duration of the P3 speed operation has reached a second predetermined time (longer than the second set time T (P3)). Alternatively or additionally, it may be determined whether or not the temperature (room temperature) measured based on the output signal of the room temperature sensor 13 has dropped to a predetermined temperature.

  When it is determined that the condition for terminating the P3 speed operation is not satisfied (FIG. 2 / STEP200... NO), the actual rotational speed R of the blower fan 3 is included in the second target speed range S2 corresponding to the P3 speed. The above-described series of processing including determination of whether or not there is performed (FIG. 2 / STEP22 to STEP29).

  When it is determined that the condition for terminating the P3 speed operation is satisfied (FIG. 2 / STEP200... YES), the P3 speed operation is stopped and the series of processes is terminated. In response to this, the combustion operation may be resumed. Each of the durations Σ1 and Σ2 is reset to zero.

(effect)
According to the gas fan heater that exhibits the above function, when the rotational speed of the blower fan 3 is controlled to 1 to 12 speed, P2 speed, and P3 speed, the actual rotational speed R of the blower fan 3 is within the target speed range ( The supply current to the fan motor 14 is corrected on the condition that it is out of the first target speed range S1 for the P2 speed and the second target speed range S2 for the P3 speed (FIG. 2). / STEP 12, 13, 18 and 19 and STEP 20-29). Thus, even if there are individual differences in the components such as the fan motor 14 and the motor driver, the actual rotational speed R of the blower fan 3 is controlled to be surely included in each target speed range (FIG. 3 / Dash-dot line) And the alternate long and two short dashes line). For this reason, during the low speed operation of the blower fan 3, it is possible to reliably prevent a situation in which the amount of air blown out from the inside of the housing 1 of the gas fan heater is excessive or excessive.

  The second target speed range S2 of the rotational speed of the blower fan 3 corresponds to a dead zone regarding the correction of the supply current to the fan motor 14 according to the actual rotational speed R of the blower fan 3. The width of the second target speed range S2 (the target speed range corresponding to at least one target rotational speed when the combustion operation of the gas burner 4 is stopped) is the target speed range corresponding to the first to twelfth speed during the combustion operation of the gas burner 4. It is set to be wider than the width. For this reason, even when the fan motor 14 has such a characteristic that the change in the rotational speed with respect to the change in the supply current is larger when the blower fan 3 is operating at the P3 speed than when operating at a higher speed. In view of this, by appropriately differentiating the widths of the plurality of dead zones, the correction frequency of the supply current can be suppressed low. As a result, not only during high speed operation of the blower fan 3 but also during low speed operation, a situation in which the actual rotational speed R becomes unstable due to the characteristics of the fan motor 14 is reliably prevented.

(Other embodiments of the present invention)
In the embodiment, two target speed ranges (first target speed range S1 and second target speed range S2 (see FIG. 3)) of the blower fan 3 when the combustion operation of the gas burner 4 is stopped are set. In the embodiment, the target speed range may be one or three or more. A target speed range corresponding to only a part of a plurality of target rotational speeds of the blower fan 3 when the combustion operation of the gas burner 4 is stopped may be set. For example, the target rotational speeds R (P2) and R (P3) of the blower fan 3 corresponding to each of the P2 speed and the P3 speed are set, while the first target speed range S1 as the target speed range of the blower fan 3 and Only one of the second target speed ranges S2 may be set. While the target rotational speed lower than the P3 speed is set, the target speed range corresponding to the target rotational speed may not be set.

  In the embodiment, (1) in addition to the actual rotational speed R of the blower fan 3 deviating from the second target speed range S2, (2) the continuation times Σ1 and Σ2 of the deviating state become the reference times TH1 and TH2. As a requirement, the number of bits of the command signal of the fan control unit 31 has been changed (see FIG. 2 / STEP 22, STEP 23, STEP 26, and STEP 27). As another embodiment, (1) The number of bits of the command signal of the fan control unit 31 may be changed only on the condition that the rotational speed R has deviated from the second target speed range S2. That is, the processes of FIG. 2 / STEP 24 to STEP 27 may be omitted.

  In the above embodiment, the number of bits of the command signal of the fan control unit 31 is changed only on the condition that the actual rotational speed R of the blower fan 3 deviates from the first target speed range S1 (FIG. 2 / As another embodiment, in addition to the actual rotational speed R of the blower fan 3 deviating from the first target speed range S1, the duration of the deviation state has reached the reference time as another embodiment. As a requirement, the number of bits of the command signal of the fan control unit 31 may be changed. In this case, the reference times TH1 and TH2 of the departure state from the first target speed range S1 are longer than the reference time of the departure state from the target speed range corresponding to the first target speed range S1 or the 1st to 12th speeds. Each reference time may be set.

DESCRIPTION OF SYMBOLS 1 ... Housing, 3 Blower fan, 4 Gas burner (combustor), 7 Control device, 14 Fan motor, 16 Rotation speed sensor

Claims (3)

A housing,
A combustor housed in the housing;
A blower fan that sucks air into the casing and blows it out of the casing as warm air by heating the air with the combustion heat of the combustor;
A fan motor as a drive source of the blower fan;
A rotational speed sensor for detecting the rotational speed of the blower fan;
A control device that controls a supply current to the fan motor so as to control the rotation speed of the blower fan to each of a plurality of target rotation speeds,
The control device sets the rotational speed of the blower fan to a plurality of target rotational speeds of the plurality of target rotational speeds during the combustion operation of the combustor and at least one target rotational speed when the combustion operation of the combustor is stopped. When the supply current to the fan motor is controlled so as to control each, the rotational speed of the blower fan detected by the rotational speed sensor is included in the target speed range including the target rotational speed as an intermediate value. Determining means for determining whether or not
Current control means for correcting the supply current to the fan motor on the condition that the determination means determines that the rotational speed of the blower fan is out of the target speed range;
A width of a target speed range that includes the at least one target rotational speed as an intermediate value when the combustion operation of the combustor is stopped includes a plurality of widths including each of the plurality of target rotational speeds during the combustion operation of the combustor as intermediate values A warm air heater characterized by being set larger than the width of the target speed range. The hot air heater according to claim 1,
Supply to the fan motor as a requirement that the current control means has reached a reference time for a continuous or cumulative time when the rotational speed of the blower fan is determined to be out of the target speed range by the determination means A hot-air heater characterized by correcting the current. The warm air heater according to claim 2,
The reference time for the at least one target rotational speed when the combustion operation of the combustor is stopped is set to be longer than the reference time for each of the plurality of target rotational speeds during the combustion operation of the combustor. A warm air heater characterized by