JP2022168924A - Forced air supply/exhaust type combustion device - Google Patents

Abstract

To provide a forced air supply/exhaust type combustion device capable of performing, with high reliability, appropriate operation control of a burner corresponding to a block-up degree of an air supply path or an air exhaust path or an air quantity.SOLUTION: A controller 30 of a forced air supply/exhaust type combustion device 1 performs operation control of a burner 3 in accordance with a difference (pressure change amount) between an in-actuation pressure detection value which is detected by a pressure sensor 24 while a blower 12 is actuated and a pre-actuation pressure reference value that is a reference value of a pressure prior to actuation start of the blower 12. The controller 30 updates the pre-actuation pressure reference value in a case where a pre-actuation pressure detection value which is detected by the pressure sensor 24 prior to the actuation start of the blower 12 is included in a predetermined range, however, does not update the pre-actuation pressure reference value in a case where the pre-actuation pressure detection value is not included in the predetermined range.SELECTED DRAWING: Figure 3

Description

The present invention relates to a forced supply/exhaust combustion apparatus such as a hot air heater.

Combustion air is supplied to a burner through an air supply path by the operation of a blower, and combustion exhaust gas generated by combustion operation of the burner is exhausted through an exhaust path. 1, the differential pressure between the upstream side and the downstream side of the orifice provided in the air supply path or the exhaust path is detected by a pressure sensor, and from the detected value of the differential pressure, the air supply path or the exhaust path is detected. It is known to prevent or stop the combustion operation of the burner when it is estimated that the degree of clogging of the passage is high.

In this case, in the technique disclosed in Patent Document 1, the detected value of the differential pressure before the start of operation of the fan is stored as the pre-operation pressure value, and then the detected value of the differential pressure during operation of the fan (pressure value during operation) The amount of change from the pre-operation pressure value is compared with a predetermined threshold value, and if the amount of change is smaller than the predetermined threshold value, it is considered that the degree of blockage of the air supply passage or the exhaust passage is high, and the burner burns The operation is not started or is stopped.

Further, for example, Patent Document 2 relates to a technique for detecting the air volume by an air blower that supplies combustion air with an air volume detector composed of a pressure sensor. Techniques for calibrating instruments are described.

JP-A-2000-304255 JP-A-8-159464

The techniques disclosed in Patent Literatures 1 and 2 assume that the air volume at the point where the pressure is detected by the pressure sensor is zero (no wind) when the blower is not in operation, and the amount of change in the pressure detection value during operation of the blower ( Based on the amount of pressure change relative to the pressure detection value when the fan is not in operation), the degree of clogging of the air supply path or the exhaust path during operation of the fan and the adequacy of the air volume are estimated.

However, even when the blower is not in operation, there are cases where the air volume at the point where the pressure is detected by the pressure sensor does not become zero due to external wind acting on the air supply path or exhaust path. , the pressure detected by the pressure sensor when the blower is not in operation includes the influence of the amount of outside wind.

In such a case, the amount of change in the pressure detection value while the fan is in operation (difference from the pressure detection value when the fan is not in operation) is calculated based on the pressure detection value of the pressure sensor when the fan is not in operation. If an attempt is made to detect the degree of clogging of the air supply path or the air exhaust path or whether the air volume is appropriate or not based on the amount of change), an erroneous detection occurs. For example, it may be erroneously detected that the degree of blockage is high even though the blockage of the air supply passage or the exhaust passage has not progressed so much, and inconveniences such as the combustion operation of the burner being stopped may occur.

SUMMARY OF THE INVENTION The present invention has been made in view of such a background, and provides a forced supply/exhaust combustion apparatus equipped with a pressure sensor for detecting the pressure corresponding to the air volume of the air supply passage or the exhaust passage. Alternatively, it is an object of the present invention to provide a forced air supply/exhaust combustion apparatus capable of appropriately controlling the operation of a burner according to the air volume with high reliability.

In order to achieve the above object, the first aspect of the forced exhaust combustion apparatus of the present invention is:
Combustion air is supplied to a burner through an air supply passage by operation of an air blower, and combustion exhaust gas generated by combustion operation of the burner is exhausted through an exhaust passage.
a pressure sensor that detects a differential pressure between an upstream side and a downstream side of an orifice provided in the air supply path or the exhaust path;
a storage unit that stores and holds a pre-operation pressure reference value that is a reference value of the pressure value detected by the pressure sensor in a stopped state before the operation of the blower is started;
During the operation of the blower, an operating pressure detection value, which is the pressure value detected by the pressure sensor, is obtained, and the pressure is the difference between the operating pressure detection value and the stored pre-operating pressure reference value. According to the amount of change, according to the degree of blockage of the air supply passage or the exhaust passage estimated from the amount of pressure change, or the air volume of the air supply passage or the exhaust passage estimated from the amount of pressure change a control unit that controls the operation of the burner according to
an update processing unit that executes processing for updating the pre-actuation pressure reference value stored in the storage unit;
The update processing unit acquires a pre-operation pressure detection value that is a pressure value detected by the pressure sensor in a stopped state before the operation of the fan is started, and determines whether the pre-operation pressure detection value is included in a predetermined range. If the pre-actuation pressure detection value is not included in the predetermined range, the pre-actuation pressure reference value stored in the storage unit is not updated, and the pre-actuation pressure detection value is The pre-actuation pressure reference value stored in the storage unit is updated according to at least the pre-actuation pressure detection value when it is included in the predetermined range. 1 invention).

In the first aspect of the invention, by appropriately setting the predetermined range, the air current caused by the external wind is prevented from flowing through the ventilation path around the orifice of the air supply path and the exhaust path in the stopped state before the operation of the blower is started. occurs, the pre-operation pressure detection value deviates from the predetermined range, and in a situation where the air passage around the orifice is in a calm state, the pre-operation pressure detection value is included in the predetermined range. can be made

If the pre-actuation pressure detection value is not within the predetermined range (if it deviates from the predetermined range), the pre-actuation pressure reference value stored in the storage unit is not updated. It is possible to prevent the pre-actuation pressure reference value from being updated using the pre-actuation pressure detection value under the influence of airflow caused by wind.

Further, when the pre-actuation pressure detection value is within the predetermined range, the pre-actuation pressure reference value is updated according to at least the pre-actuation pressure detection value. It is possible to update the pre-actuation pressure reference value by reflecting the pre-actuation pressure detection value.

As a result, the amount of pressure change during the operation of the blower serves as a highly reliable index value corresponding to the degree of clogging of the air supply passage or the exhaust passage and the air volume of the air supply passage or the exhaust passage. Therefore, according to the amount of pressure change, according to the degree of clogging of the air supply passage or the exhaust passage estimated from the amount of pressure change, or according to the air volume of the air supply passage or the exhaust passage estimated from the amount of pressure change By controlling the operation of the burner accordingly, it is possible to perform appropriate operation control of the burner according to the degree of blockage of the air supply path or exhaust path or the air volume with high reliability.

In the first aspect, when the pre-actuation pressure detection value is included in the predetermined range, the update processing unit converts the pre-actuation pressure detection value to a setting pressure detection value for newly setting the predetermined range. and the predetermined range to be compared with the pre-operation pressure detection value acquired in the stopped state before the operation of the blower is started is the average of the plurality of previously stored setting pressure detection values It is preferable that it is configured to be set within a range centered on the value (second invention).

According to this, even if the steady drift (offset from the initial state) of the output of the pressure sensor occurs in windless conditions, the influence thereof is appropriately compensated, and the predetermined range to be compared with the pre-actuation pressure detection value is established. Can be set properly. As a result, whether or not the pre-actuation pressure detection value is included in the predetermined range can increase reliability as an indication of whether or not the ventilation path around the orifice is in a windless state.

In the first or second invention, when updating the pre-actuation pressure reference value stored in the storage unit, the update processing unit changes the pre-actuation pressure reference value to the pre-actuation pressure detection value. It can be configured to update (third invention).

According to this, the drift of the output of the pressure sensor in no wind conditions and the influence of variations in output characteristics are appropriately compensated for, and the differential pressure across the orifice detected by the pressure sensor in no wind conditions is assumed to be equivalent to can appropriately set the pre-actuation pressure reference value.

Moreover, in order to achieve the above object, a second aspect of the forced supply and exhaust type combustion apparatus of the present invention provides:
Combustion air is supplied to a burner through an air supply passage by operation of an air blower, and combustion exhaust gas generated by combustion operation of the burner is exhausted through an exhaust passage.
a pressure sensor that detects a differential pressure between an upstream side and a downstream side of an orifice provided in the air supply path or the exhaust path;
a storage unit that stores and holds a pre-operation pressure reference value that is a reference value of the pressure value detected by the pressure sensor in a stopped state before the operation of the blower is started;
During the operation of the blower, an operating pressure detection value, which is the pressure value detected by the pressure sensor, is obtained, and the pressure is the difference between the operating pressure detection value and the stored pre-operating pressure reference value. According to the amount of change, according to the degree of blockage of the air supply passage or the exhaust passage estimated from the amount of pressure change, or the air volume of the air supply passage or the exhaust passage estimated from the amount of pressure change a control unit that controls the operation of the burner according to
an update processing unit that executes processing for updating the pre-actuation pressure reference value stored in the storage unit;
The update processing unit acquires a pre-operation pressure detection value that is a pressure value detected by the pressure sensor in a stopped state before the operation of the fan is started, and determines whether the pre-operation pressure detection value is included in a predetermined range. If the pre-actuation pressure detection value is not included in the predetermined range, the number of consecutive occurrences of the event not being included in the predetermined range is counted, and the counted number of times is a predetermined number. When the counted number of times has been reached, the pre-actuation pressure reference value stored in the storage unit is updated according to at least the pre-actuation pressure detection value, and when the counted number of times is less than the predetermined number of times , the pre-actuation pressure reference value stored in the storage unit is not updated (fourth invention).

In the fourth invention, as in the first invention, by appropriately setting the predetermined range, the ventilation path around the orifice of the air supply path and the exhaust path in the stopped state before the operation of the blower is started. In a situation where an air current caused by an outside wind is generated, the pre-operation pressure detection value deviates from the predetermined range, and in a situation where the air passage around the orifice is in a windless state, the pre-operation pressure detection value can be included within a predetermined range.

Here, even if the ventilation path around the orifice is in a dead state before the operation of the blower is started, the steady drift of the output of the pressure sensor (offset from the initial state) causes the pre-operation pressure The detected value may constantly deviate from the predetermined range. On the other hand, when the blower is stopped before it starts operating, the situation in which an air current is generated in the ventilation path around the orifice due to external wind is generally a temporary situation.

Therefore, in the fourth invention, when the pre-actuation pressure detection value is not included in the predetermined range (when it deviates from the predetermined range), the number of consecutive occurrences of the event not being included in the predetermined range is counted. reaches a predetermined number, the pre-actuation pressure reference value is updated at least according to the pre-actuation pressure detection value. As a result, when there is a steady drift in the output of the pressure sensor, the pre-operation pressure detection value (pre-operation pressure detection including the influence of value) to update the pre-actuation pressure reference value.

Further, if the counted number of times is less than the predetermined number, the pre-actuation pressure reference value is not updated. can be used to prevent the pre-actuation pressure reference value from being updated.

As a result, the amount of pressure change during the operation of the blower serves as a highly reliable index value corresponding to the degree of clogging of the air supply passage or the exhaust passage and the air volume of the air supply passage or the exhaust passage. Therefore, according to the amount of pressure change, according to the degree of clogging of the air supply passage or the exhaust passage estimated from the amount of pressure change, or according to the air volume of the air supply passage or the exhaust passage estimated from the amount of pressure change By controlling the operation of the burner accordingly, it is possible to perform appropriate operation control of the burner according to the degree of blockage of the air supply path or exhaust path or the air volume with high reliability.

In the fourth invention, when the pre-actuation pressure detection value is included in a predetermined range, the pre-actuation pressure reference value is updated at least according to the pre-actuation pressure detection value, as in the first invention, or , or a mode in which the pre-actuation pressure reference value is not updated.

In the fourth invention, the update processing section may be configured to set the predetermined range to a range centered on the pre-actuation pressure reference value stored in the storage section (fifth invention).
According to this, it is appropriate to set the predetermined range so that whether or not the pre-actuation pressure detection value is included in the predetermined range depends on whether the ventilation path around the orifice is in a calm state. realizable.

In the fourth or fifth invention, the update processing unit updates the pre-actuation pressure detection value to the pre-actuation pressure reference value when the pre-actuation pressure detection value is not within the predetermined range. and updating the pre-actuation pressure reference value stored in the storage unit when the number of times counted reaches the predetermined number of times. In this case, the pre-actuation pressure reference value is preferably updated to the average value of the pre-actuation pressure detection values stored at each of the predetermined times (sixth invention).

According to this, the pre-operation pressure detection value (pre-operation pressure detection value including the influence of drift) in a situation where the air passage around the orifice is in a windless state is preferably reflected, and the influence of disturbance noise is reduced. It is possible to update the pre-actuation pressure reference value so that it is reduced as much as possible. As a result, it is possible to improve the reliability of the pre-actuation pressure reference value as equivalent to the value of the differential pressure across the orifice detected by the pressure sensor in no wind.

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows the mechanical structure of the hot air heater of embodiment (1st Embodiment or 2nd Embodiment) of this invention. The block diagram which shows the structure regarding control of the warm air heater of embodiment. FIG. 3 is a flow chart showing processing in the first embodiment of the controller shown in FIG. 2; FIG. FIG. 3 is a flow chart showing processing in the second embodiment of the controller shown in FIG. 2; FIG.

[First embodiment]
A first embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. Referring to FIG. 1, the forced air supply/exhaust combustion apparatus of this embodiment is, for example, a hot air heater 1. As shown in FIG. This hot-air heater 1 includes a main body case 2 disposed indoors, a combustion chamber 4 containing a burner 3, a heat exchange section 4a communicating with the combustion chamber 4, indoor air suction and warm air. and a convection fan 5 for blowing out.

The combustion chamber 4 is connected to an air supply cylinder 10 having therein an air supply passage 10a serving as a ventilation passage for supplying combustion air to the burner 3. An exhaust pipe 11 which internally forms an exhaust passage 11a, which is a vent passage for exhausting exhaust gas, is connected via a heat exchange portion 4a. The air supply passage 10a communicates with the exhaust passage 11a through the combustion chamber 4 and the heat exchange portion 4a, and hereinafter, the air passage from the air supply passage 10a to the exhaust passage 11a may be generically referred to as an air supply and exhaust passage. .

The air supply cylinder 10 extends from the combustion chamber 4 to the outside through an indoor space outside the main body case 2, and its upstream end opens to the outside as an air supply port 10b. Further, the exhaust pipe 11 extends from the downstream end of the heat exchange portion 4a to the outside through the indoor space outside the main body case 2, and the downstream end thereof is opened to the outside as an exhaust port 11b. In addition, in the warm air heater 1 of the illustrated example, the downstream portion of the exhaust pipe 11 is concentrically arranged inside the upstream portion of the supply pipe 10 . However, the entire exhaust pipe 11 may be arranged outside the intake pipe 10 .

A combustion fan 12 as a blower for supplying combustion air to the burner 3 is assembled to the air supply cylinder 10 . An electric motor 12a is connected to the combustion fan 12 to drive it. By rotating the combustion fan 12 with the electric motor 12a, outside air (outdoor air) is sucked from the air supply port 10b into the air supply passage 10a in the cylinder 10, and the sucked outside air is transferred to the combustion fan. 12, it is supplied as combustion air to the burner 3 in the combustion chamber 4 from the air supply passage 10a. In this case, it is possible to increase or decrease the amount of combustion air supplied to the burner 3 by controlling the rotational speed (rotational speed) of the combustion fan 12 .

The burner 3 is a gas burner having a known structure in this embodiment, and fuel gas is supplied from a fuel gas supply source (not shown) through a gas supply pipe 14 as a fuel supply passage. The burner 3 mixes the fuel gas supplied from the gas supply pipe 14 and the combustion air supplied from the air supply passage 10a by the rotational operation of the combustion fan 12, and the mixture obtained by the mixture is configured to burn.

The gas supply pipe 14 is provided with two solenoid valves 15a and 15b that can be opened and closed, and a fuel control valve 16 such as a proportional valve for adjusting the amount of fuel gas supplied to the burner 3. By controlling the fuel control valve 16 while controlling the opening of the solenoid valves 15a and 15b, the amount of fuel gas supplied to the burner 3 can be controlled to increase or decrease.

In the combustion chamber 4, there are also provided a spark plug 18 for generating spark discharge for igniting the burner 3 by operating an igniter 17 (shown in FIG. A flame detection sensor 19 is arranged. The flame detection sensor 19 is composed of, for example, a flame rod, a thermocouple, or the like.

The convection fan 5 is arranged inside the body case 2 so as to face a suction port 2a formed in the rear portion of the body case 2, and is connected to an electric motor 5a that drives the convection fan 5 to rotate. By rotating the convection fan 5 by an electric motor 5a, the indoor air is sucked into the main body case 2 through the suction port 2a, and the sucked air is blown into the main body case 2. After passing through the passage 2b, the air is blown indoors from the outlet 2c formed in the front portion of the main body case 2. As shown in FIG.

In this case, a heat exchanging portion 4a is arranged in the ventilation passage 2b. Therefore, when the convection fan 5 is rotationally driven by the electric motor 5a while the burner 3 is in combustion operation, the combustion exhaust gas generated by the combustion operation of the burner 3 flows through the heat exchange section 4a into the exhaust passage 11a. Then, heat exchange (heat transfer) is performed from the combustion exhaust gas to the indoor air flowing through the ventilation passage 2b. As a result, the indoor air passing through the blowing passage 2b is heated in the heat exchange section 4a, and the heated air is blown indoors from the outlet 2c as warm air.

Further, at the rear part of the body case 2, a temperature sensor 20 for detecting the temperature of the air introduced into the air passage 2b from the suction port 2a as the room temperature of the room where the warm air heater 1 is arranged is attached to the suction port 2a. It is placed in front of you.

In the warm air heater 1 of the present embodiment, an orifice 21 is further formed in the midway portion of the air supply path 10a or the exhaust path 11a, for example, in the air supply path 10a on the upstream side of the combustion fan 12. As shown in FIG. This orifice 21 is closed when a normal airflow is generated by the rotational operation of the combustion fan 12 in the air supply/exhaust passage (including the combustion chamber 4 and the heat exchange section 4a) from the air supply passage 10a to the exhaust passage 11a. A differential pressure between the pressure on the upstream side and the pressure on the downstream side is generated.

In the vicinity of the orifice 21, an upstream communication pipe 22 communicating with the air supply passage 10a on the upstream side of the orifice 21 and a downstream communication pipe 23 communicating with the air supply passage 10a on the downstream side of the orifice 21 are provided. , and these upstream communication pipe 22 and downstream communication pipe 23 are connected to a pressure sensor 24 arranged outside the air supply passage 10a. The pressure sensor 24 is a sensor of a known structure capable of detecting a differential pressure between the upstream side and the downstream side of the orifice 21 (hereinafter referred to as differential pressure across the orifice). Configured.

As shown in FIG. 2, the warm air heater 1 further includes a controller 30 having a function of controlling the operation of the warm air heater 1 and an operation unit 40 for a user to operate the warm air heater 1. It has

The operation unit 40 is mounted, for example, on the surface of an exterior case (not shown) of the hot air heater 1 (an exterior case containing the main body case 2), or on a remote control unit capable of communicating with the controller 30. FIG. Although detailed illustration is omitted, the operation unit 40 includes a switch for turning on/off the operation of the warm air heater 1, a switch for setting a target room temperature (or its level), and the like. Be prepared.

The controller 30 is composed of one or more electronic circuit units including a processor such as a microcomputer, a memory, an interface circuit, etc., and is mounted inside an exterior case (not shown) of the warm air heater 1, for example. The controller 30 receives detection signals from the sensors provided in the hot air heater 1, such as the flame detection sensor 19, the temperature sensor 20, and the pressure sensor 24, and also receives an operation signal from the operation unit 40. be done.

The controller 30 has functions realized by the implemented hardware configuration and programs (software configuration), including the electric motors 5a and 12a for rotating the convection fan 5 and the combustion fan 12, the gas supply pipe 14 The function as an operation control unit 31 that controls the operation of the warm air heater 1 through the operation control of the solenoid valves 15a and 15b and the fuel adjustment valve 16, and the igniter 17 for driving the spark plug 18, and the function of the combustion fan 12 A function as a storage unit 32 for storing and holding a pre-operation pressure reference value, which is a reference value of the differential pressure across the orifice detected by the pressure sensor 24 in a stopped state before operation is started, and a pre-operation pressure reference to be stored in the storage unit 32. and a function as an update processing unit 33 that executes processing for appropriately updating values. Note that the operation control unit 31 corresponds to the control unit in the present invention.

Next, the operation of the warm air heater 1 of the present embodiment will be described, focusing on the control processing executed by the controller 30. FIG. When the controller 30 is instructed to start operation of the warm-air heater 1 by the operation of the operation unit 40 by the user (operation for starting the operation of the warm-air heater 1) or by the timer operation function of the warm-air heater 1, , the processing shown in the flow chart of FIG. 3 is executed.

First, the controller 30 causes the update processing section 33 to execute the processing of STEPs 1 to 6 before starting the operation of the combustion fan 12 (while the operation of the combustion fan 12 is stopped). In STEP 1, the update processing unit 33 converts the current detected value of the differential pressure DP across the orifice detected by the pressure sensor 24 to a detected pressure value before operation, which is the detected value of the differential pressure across the orifice before the combustion fan 12 starts operating. Obtained as DP0.

Next, in STEP 2, the update processing unit 33 determines whether the pre-actuation pressure detection value DP0 acquired in STEP 1 is a detection value in a state (no wind state) in which no air current is generated in the air supply/exhaust passage due to external wind. In order to determine whether or not, the lower limit value Lp1 and the upper limit value Hp1 of a predetermined range for the pre-operation pressure detection value DP0 are obtained from a plurality of (predetermined number) of pre-operation pressures obtained before the combustion fan 12 started operating in the past. It is determined according to the average value (past average value) a1(y) of the detected values. Details of the processing of STEP2 will be described later.

In the next STEP3, the update processing unit 33 determines whether or not the pre-actuation pressure detection value DP0 is within a predetermined range between the lower limit value Lp1 and the upper limit value Hp1 determined in STEP2 (Lp1≤DP0≤Hp1). is there or not). Here, in a state in which no air current is generated in the air supply/exhaust passage (no wind state), or in a state close to this, the determination result in STEP3 is affirmative.

Then, when the determination result in STEP3 is affirmative, the update processing unit 33 updates the value of the pre-actuation pressure reference value A to be stored and held in the storage unit 32 in STEP4. Update according to the value DP0. Specifically, the update processing unit 33 sets the pre-actuation pressure detection value DPO acquired in STEP 1 as the updated value (post-update value) of the pre-actuation pressure reference value A, thereby increasing the pre-actuation pressure reference value A to Update. As a result, the pre-actuation pressure detection value DPO as the detection value of the differential pressure across the orifice detected by the pressure sensor 24 in a state in which no air current is generated by the external wind in the air supply/exhaust passage, or in a state close thereto, is actuated. It is stored and held in the storage unit 32 as the front pressure reference value A.

Next, in STEP 5, the update processing unit 33 increases the value of the parameter x (hereinafter simply referred to as the update count x) indicating the number of updates of the pre-actuation pressure reference value A by "1". The pressure detection value DP0 (the current pre-actuation pressure detection value DP0 obtained in STEP1) is stored as the value of the parameter a1(x) associated with the update count x after the increase in STEP5. The parameter a1(x) is a parameter for storing the setting pressure detection value used to set the lower limit value Lp1 and the upper limit value Hp1 of the predetermined range in STEP2.

On the other hand, when the determination result in STEP3 is negative (when DP0<Lp1 or DP0>Hp1), the pre-actuation pressure detection value DP0 acquired in STEP1 is the air current generated by the external wind in the supply/exhaust passage. There is a high possibility that it is the detected value of the differential pressure across the orifice detected by the pressure sensor 24 in the state where the pressure is on. Therefore, in this case, the update processing unit 33 does not execute the processing of STEP 4 to STEP 6 (and thus does not update the pre-operation pressure reference value A). The processing before starting the operation of the combustion fan 12 ends.

Here, the processing of STEP2, whose explanation is postponed, will be explained. In this embodiment, the update processing unit 33 updates the pre-operation pressure reference value A obtained in STEP 1 each time the determination result in STEP 3 becomes affirmative (in other words, each time the pre-operation pressure reference value A is updated) by the processing in STEP 6 described above. The detected pressure value DP0 is stored as the value of parameter a1(x) (x=1, 2, . . . ).

Then, in STEP 2, the update processing unit 33 updates the past average value a1(y) of the pre-actuation pressure detection value DP0 to the previous (one previous) update from the time when the pre-actuation pressure reference value A was updated a predetermined number of times before. It is calculated as the average value of the pre-actuation pressure detection values DPO for a plurality of times up to the time.

Specifically, for example, the average value of the pre-actuation pressure detection values DP0 obtained when the pre-actuation pressure reference value A is updated five times can be calculated as the past average value a1(y). In this case, the pre-actuation pressure detection values DP0 acquired at each update from five times before the previous (one time before) of the pre-actuation pressure reference value A are the parameters a1(x-4) and a1(x- 3), a1(x-2), a1(x-1), and a1(x), so the past average value a1(y) of the pre-actuation pressure detection value DP0 is given by the following equation (1) Calculated by

a1(y)=(a1(x-4)+a1(x-3)+a1(x-2)+a1(x-1)+a1(x))/5
……(1)

Then, in STEP 2, the update processing unit 33 sets the lower limit value Lp1 of the predetermined range for the pre-actuation pressure detection value DP0 as shown in the following equations (2a) and (2b) to be lower than the past average value a1(y). A value (=a1(y)-α1) smaller than a predetermined value α1 is set, and a value (=a1(y)−α1) larger than the past average value a1(y) by the predetermined value α1 is set as the upper limit value Hp1 of the predetermined range. =a1(y)+α1). As a result, the predetermined range for the pre-actuation pressure detection value DPO is determined as a range centered on the past average value a1(y) of the pre-actuation pressure detection value DPO.

Lp1=a1(y)-α1 (2a)
Hp1=a1(y)+α1 (2b)

Note that when the number of updates of the pre-actuation pressure reference value A (the number of times the judgment result in STEP 3 has become affirmative) is less than the predetermined number of times (for example, 5 times) required to calculate the past average value a1(y) In STEP2, for example, predetermined values are set as the lower limit value Lp1 and the upper limit value Hp1. Alternatively, for example, the value (=A-α1) smaller than the current pre-actuation pressure reference value A by the predetermined value α1 and the value (=A+α1) larger than the current pre-actuation pressure reference value A by the predetermined value α1 are the lower limit value Lp1 and the upper limit value Hp1, respectively. is set as

Supplementally, the value of the above-mentioned predetermined value α1 is such that the determination result in STEP 3 becomes affirmative when no air current is generated in the air supply/exhaust passage (no wind) or in a state close to this, Based on experiments and the like, the determination result in STEP 3 is set to be negative in a state in which a differential pressure across the orifice acts on the pressure sensor 24 due to the airflow generated in the air supply and exhaust passage.

The processing of the update processing unit 33 is executed as described above. After executing the processing of the update processing unit 33 in STEPs 1 to 6 as described above, the controller 30 executes the processing of STEPs 7 and 8 by the operation control unit 31 . In STEP7, the operation control unit 31 controls the electric motor 12a to start rotating the combustion fan 12 (turns on the combustion fan 12). Although not shown in FIG. 3, in STEP7, the operation control unit 31 further ignites the burner 3 to start the combustion operation of the burner 3, and the convection fan 5 via the electric motor 5a. start the operation of In this case, in the ignition processing of the burner 3, the operation control unit 31 controls the rotational speed of the combustion fan 12 to a predetermined rotational speed for ignition via the electric motor 12a, the electromagnetic valve 15a of the gas supply pipe 14, 15b is controlled to open, the amount of fuel gas supplied to the burner 3 is controlled to the supply amount for ignition via the fuel control valve 16, and spark discharge is generated at the ignition plug 18 via the igniter 17. and perform.

Further, after the combustion operation of the burner 3 is started, the operation control unit 31 controls the target temperature (or its degree of high or low) set by the user by operating the operation unit 40 and the room temperature detected by the temperature sensor 20. , the combustion amount of the burner 3 and the rotational speed of the convection fan 5 are controlled to perform the heating operation of the warm air heater 1. - 特許庁In this case, the combustion amount of the burner 3 is controlled through the control of the rotational speed of the combustion fan 12 (control of the amount of combustion air supplied) and the control of the fuel control valve 16 (control of the amount of fuel gas supplied). will be

Then, the operation control unit 31 executes the process of STEP8 while the combustion fan 12 is operating. In STEP 8, the operation control unit 31 sequentially acquires the operating pressure detection value, which is the differential pressure DP across the orifice detected by the pressure sensor 24, and the difference between the operating pressure detection value and the pre-operating pressure reference value A. Based on the amount of pressure change, which is the difference (=detected pressure value during operation−A), a process of determining the degree of blockage of the air supply/exhaust passage from the air supply passage 10a to the exhaust passage 11a is executed.

Specifically, in the present embodiment, the operation control unit 31 sequentially determines whether or not the amount of pressure change has become smaller than a predetermined threshold value. Here, when the blockage of the air supply/exhaust passage progresses to some extent (when the degree of blockage increases), the air volume in the air supply/exhaust passage decreases, so the pressure change amount becomes smaller than the predetermined threshold value. In this case, since an appropriate amount of combustion air cannot be supplied to the burner 3, the operation control unit 31 closes one or both of the electromagnetic valves 15a and 15b, thereby The combustion operation of 3 is forcibly stopped. Furthermore, the operation control unit 31 outputs error information indicating that the degree of blockage of the air supply/exhaust passage is high via a display (not shown) of the warm air heater 1 or the like.

In the present embodiment, the processing of the update processing unit 33 is executed as described above, so that when the combustion fan 12 is stopped before the operation is started, an air current is generated by the external wind in the air supply and exhaust passage (and thus, In a state in which the differential pressure across the orifice detected by the pressure sensor 24 is affected by the airflow, it is possible to prevent the pre-actuation pressure reference value A from being updated using the pre-actuation pressure detection value DPO.

In a stopped state before the combustion fan 12 starts operating, in a state in which there is no airflow due to external wind in the air supply/exhaust passage (no wind state) or in a state close to this, the pre-operation pressure reference value A is the pre-operation pressure detection value. It is updated with the value DP0.

Therefore, the storage unit 32 can store and hold the highly reliable pre-actuation pressure reference value A that corresponds to the detected value of the differential pressure across the orifice in the windless state of the air supply/exhaust passage. As a result, the amount of pressure change during operation of the combustion fan 12 has high reliability as an index value corresponding to the degree of clogging of the air supply/exhaust passage and the air volume.

Therefore, when the degree of blockage of the air supply/exhaust passage is high (and when an appropriate amount of combustion air cannot be supplied to the burner 3), it is possible to stop the combustion operation of the burner 3 at an appropriate timing. . Moreover, it is possible to prevent the combustion operation of the burner 3 from being stopped due to an erroneous detection that the degree of blockage is high even though the degree of blockage of the air supply/exhaust passage is sufficiently low.

In this embodiment, the lower limit value Lp1 and the upper limit value Hp1 of the predetermined range to be compared with the pre-actuation pressure detection value DP0 in STEP 3 are set as described above. , a predetermined range suitable for the pre-actuation pressure detection value DPO including the influence of the drift can be appropriately set. As a result, it is possible to prevent a situation in which the result of determination in STEP 3 is negative even though the air supply/exhaust passage is in the windless state.

By updating the pre-operation pressure reference value A when the pre-operation pressure detection value DPO is included in the predetermined range, an appropriate pre-operation pressure reference value A is stored for the pressure sensor 24 in which steady drift has occurred. It can be stored in the unit 32 .

[Second embodiment]
Next, a second embodiment of the invention will be described with reference to FIG. This embodiment differs from the first embodiment only in the processing of the update processing unit 33 of the controller 30, so the description of the same items as in the first embodiment will be omitted.

In this embodiment, the controller 30 starts the operation of the warm air heater 1 by the operation of the operation unit 40 by the user (the operation of starting the operation of the warm air heater 1) or by the timer operation function of the warm air heater 1. is instructed, the process shown in the flowchart of FIG. 4 is executed.

First, the controller 30 causes the update processing section 33 to execute the processing of STEP 11 to STEP 20 before starting the operation of the combustion fan 12 (while the operation of the combustion fan 12 is stopped). In STEP 11, the update processing unit 33 replaces the current detected value of the differential pressure across the orifice detected by the pressure sensor 24 with a pre-operation pressure detection value DP0, which is the detected value of the differential pressure across the orifice before the combustion fan 12 starts operating. to get as

Next, in STEP 12, the update processing unit 33 determines whether or not the pre-actuation pressure detection value DPO is close to the current pre-actuation pressure reference value A. A lower limit value Lp2 and an upper limit value Hp2 of are determined according to the current pre-actuation pressure reference value A.

In this case, the update processing unit 33, as shown in the following equations (3a) and (3b), sets the lower limit value Lp2 of the predetermined range for the pre-actuation pressure detection value DP0 to be lower than the current pre-actuation pressure reference value A. A value (=A-α2) that is smaller than the current pre-actuation pressure reference value A by the predetermined value α2 (=A+α2) is set as the upper limit value Hp2 of the predetermined range. do. As a result, the predetermined range for the pre-actuation pressure detection value DPO is determined as a range centered on the current pre-actuation pressure reference value A. FIG.

Lp2=A-α2 (3a)
Hp2=A+α2 (3b)

In the next STEP 13, the update processing unit 33 determines whether or not the pre-actuation pressure detection value DP0 is within a predetermined range between the lower limit value Lp2 and the upper limit value Hp2 (whether Lp2≤DP0≤Hp2). ). Here, there is no airflow due to the external wind in the air supply/exhaust passage, or a state close to this, and drift of the output of the pressure sensor 24 due to deterioration of the pressure sensor 24 or the like does not occur. Or, if the drift is sufficiently small, the determination result in STEP 13 becomes affirmative (the value of the predetermined value α2 is set in advance based on experiments and the like so as to achieve this). .

If the determination result in STEP 13 is affirmative, the current pre-actuation pressure reference value A is set to the pressure in a state in which there is no airflow due to outside wind in the air supply/exhaust passage (no wind state), or in a state close to this. It can be regarded as matching or substantially matching the value of the differential pressure across the orifice detected by the sensor 24 .

In this case, the update processing unit 33 initializes the count value n to zero in STEP 14 without updating the pre-operation pressure reference value A, and terminates the processing before the start of the current operation of the combustion fan 12 . The count value n is a parameter for counting the number of consecutive negative judgment results in STEP13.

As a situation in which the determination result in STEP 13 is negative, the current pre-actuation pressure reference value A is changed from the air supply path 10a or the exhaust path 11a due to the steady drift of the output of the pressure sensor 24. Detected value of differential pressure across the orifice detected by the pressure sensor 24 in a state where there is no airflow due to outside wind (windless state), or in a state close to this (indicated by the output of the pressure sensor 24 including the influence of drift) Detected value), or due to the temporary occurrence of an air current due to the external wind in the air supply path 10a or the exhaust path 11a, the pre-actuation pressure detection value DPO is different from the pre-actuation pressure reference value A. It is conceivable that the values deviate from each other.

Therefore, when the determination result of STEP13 is negative (when DP0<Lp1 or DP0>Hp1), the update processing unit 33 executes the processing from STEP15. In STEP 15, the update processing unit 33 increases the count value n by "1", and in STEP 16, the current pre-actuation pressure detection value DP0 (the pre-actuation pressure detection value DP0 acquired in STEP 1) is changed to the count value n. is stored as the value of the parameter a2(n) associated with . As a result, when the determination result in STEP 13 is repeatedly negative, the pre-actuation pressure detection value DP0 is sequentially stored as the values of the parameters a2(1), a3(2), . . . be done. The pre-actuation pressure detection value DPO stored as the values of the parameters a2(1), a3(2), .

Next, in STEP 17, the update processing unit 33 determines whether or not the current count value n has reached a predetermined number N (for example, N=5). That is, it is determined whether or not the number of consecutive times that the determination result in STEP 13 becomes negative has reached a predetermined number N.

Here, in a situation where the determination result in STEP 13 is negative due to the temporary occurrence of an air current due to the external wind in the air supply/exhaust passage, the determination result in STEP 17 is generally negative. In this case, the update processing unit 33 ends the processing before the start of the current operation of the combustion fan 12 without updating the pre-operation pressure reference value A.

On the other hand, due to the steady drift of the output of the pressure sensor 24, the current pre-operation pressure reference value A is in a state where no airflow is generated in the air supply path 10a or the exhaust path 11a due to external wind (no wind state). , or in a state similar to this, if the detected value of the differential pressure across the orifice detected by the pressure sensor 24 deviates from the detected value (the detected value indicated by the output of the pressure sensor 24 including the influence of drift), the hot air heater 1 (immediately before the operation of the combustion fan 12) is continuously repeated to be negative. As a result, the judgment result of STEP17 becomes affirmative.

In this case, each time the determination result in STEP 13 becomes negative, the update processing unit 33 updates the values of the predetermined number N of parameters a2(1), a2(2), . , and the average value a2(y) thereof is calculated in STEP18. The average value a2(y) is calculated by the following equation (4).

a2(y)=(a2(1)+a2(2)+...+a2(N))/N...(4)

Next, in STEP 19, the update processing unit 33 updates the pre-actuation pressure reference value A stored in the storage unit 32 according to the average value a2(y). Specifically, the update processing unit 33 updates the pre-actuation pressure reference value A by setting the average value a2(y) as the updated value (post-update value) of the pre-actuation pressure reference value A. As a result, when the negative determination result in STEP 13 is continuously repeated a predetermined number of times (=predetermined number N), the orifice detected by the pressure sensor 24 before the combustion fan 12 starts operating each time. The average value a2(y) of the pre-actuation pressure detection values DP0 as the detection value of the differential pressure before and after operation is stored in the storage unit 32 as the pre-actuation pressure reference value A. FIG.

Next, in STEP 20, the update processing unit 33 initializes the count value n to zero, and terminates the processing before the combustion fan 12 starts operating this time.

After executing the processing of the update processing unit 33 in STEPs 11 to 20 as described above, the controller 30 executes the processing of STEPs 21 and 22 by the operation control unit 31 . The processing of these STEPs 21 and 22 is the same as the processing of STEPs 7 and 8 in the first embodiment. Combustion operation of the burner 3 is also performed in the same manner as in the first embodiment.

In the present embodiment, the processing of the update processing unit 33 is executed as described above, so that when the combustion fan 12 is stopped before the operation is started, an air current is generated by the external wind in the air supply and exhaust passage (and thus, In a state in which the differential pressure across the orifice detected by the pressure sensor 24 is affected by the airflow, it is possible to prevent the pre-actuation pressure reference value A from being updated using the pre-actuation pressure detection value DPO.

The pressure sensor 24 detects the pre-operation pressure detection value DP0 in a state in which no air current is generated in the air supply/exhaust passage due to external wind (windless state) or in a state close to this in a stopped state before the combustion fan 12 starts operating. If the determination result in STEP 13 is affirmative due to the steady drift (not minute drift) of the output of , the average value of the pre-actuation pressure detection values DPO for multiple times is used. , the pre-actuation pressure reference value A is updated.

Therefore, the storage unit 32 can store and hold the highly reliable pre-actuation pressure reference value A that corresponds to the detected value of the differential pressure across the orifice in the windless state of the air supply/exhaust passage. As a result, the amount of pressure change during operation of the combustion fan 12 has high reliability as an index value corresponding to the degree of clogging of the air supply/exhaust passage and the air volume.

Therefore, when the degree of blockage of the air supply/exhaust passage is high (and when an appropriate amount of combustion air cannot be supplied to the burner 3), it is possible to stop the combustion operation of the burner 3 at an appropriate timing. . Moreover, it is possible to prevent the combustion operation of the burner 3 from being stopped due to an erroneous detection that the degree of blockage is high even though the degree of blockage of the air supply/exhaust passage is sufficiently low.

In addition, in the present embodiment, the pre-actuation pressure reference value A is updated by appropriately reflecting the influence caused by the steady drift of the output of the pressure sensor 24. Therefore, in STEP 13, the pre-actuation pressure reference value A is compared with the pre-actuation pressure detection value DP0. By setting the lower limit value Lp2 and the upper limit value Hp2 of the predetermined range, as described above, a predetermined range suitable for the pre-actuation pressure detection value DPO including the influence of drift of the output of the pressure sensor 24 can be set. As a result, it is possible to prevent frequent negative determination results in STEP 13 and unnecessary updating of the pre-actuation pressure reference value A due to the influence of a breeze generated in the air supply and exhaust passage.

In this embodiment, if the determination result in STEP 13 is affirmative, the pre-actuation pressure reference value A is not updated. The pre-actuation pressure reference value A may be updated in the same manner as in the processing of STEP 4 of one embodiment.

[Other embodiments]
The present invention is not limited to the first and second embodiments, and other embodiments can be adopted. Some other embodiments are illustrated below.

In each of the above-described embodiments, the combustion operation of the burner 3 is stopped when the amount of pressure change during operation of the combustion fan 12 (=pressure detection value during operation-A) is smaller than a predetermined threshold value. However, for example, the degree of blockage of the air supply/exhaust passage is estimated from the amount of pressure change during operation of the combustion fan 12, and when the estimated value of the degree of blockage exceeds a predetermined threshold value, the combustion operation of the burner 3 is stopped. You may do so. Alternatively, the air volume in the air supply/exhaust passage is estimated from the amount of pressure change during operation of the combustion fan 12, and when the estimated value of the air volume becomes smaller than a predetermined threshold value, the burner 3 combustion operation is stopped. good too.

Furthermore, for example, according to the amount of pressure change, according to the degree of blockage of the air supply/exhaust passage estimated from the amount of pressure change, or according to the air volume of the air supply/exhaust passage estimated from the amount of pressure change. By appropriately correcting the rotation speed of the combustion fan 12 from the rotation speed when the air supply/exhaust passage is normal, even if the degree of clogging of the air supply/exhaust passage becomes high to some extent, the combustion operation of the burner 3 is continued. An appropriate amount of combustion air may be supplied to the burner 3 .

Further, in each of the above embodiments, the pressure sensor 24 is provided on the side of the air supply path 10a, but the pressure sensor 24 may be provided on the side of the exhaust path 11a.

Further, in the first embodiment, when the determination result in STEP3 is affirmative, the pre-operation pressure reference value A is updated to the pre-operation pressure detection value DP0 acquired in the immediately preceding STEP1. The average value of the pre-operation pressure detection values DPO obtained before the start of operation of the combustion fan 12 a plurality of times (including the pre-operation pressure detection values DPO obtained before the current start of operation of the combustion fan 12) is used as the pre-operation pressure reference. It may be set as a value after updating the value A.

Further, in each of the above embodiments, the hot air heater 1 was exemplified as the forced air supply and exhaust type combustion apparatus, but the forced air supply and exhaust type combustion apparatus of the present invention is not limited to the hot air heater, and can be used as a heat source for, for example, a water heater. It may be a combustion device provided in the machine.

REFERENCE SIGNS LIST 1 warm air heater (forced supply and exhaust type combustion device) 3 burner 10a air supply path 11a exhaust path 12 combustion fan (blower) 21 orifice 24 pressure sensor 31 operation Control unit (control unit), 32... Storage unit, 33... Update processing unit.

Claims (6)

Combustion air is supplied to a burner through an air supply passage by operation of an air blower, and combustion exhaust gas generated by combustion operation of the burner is exhausted through an exhaust passage.
a pressure sensor that detects a differential pressure between an upstream side and a downstream side of an orifice provided in the air supply path or the exhaust path;
a storage unit that stores and holds a pre-operation pressure reference value that is a reference value of the pressure value detected by the pressure sensor in a stopped state before the operation of the blower is started;
During the operation of the blower, an operating pressure detection value, which is the pressure value detected by the pressure sensor, is obtained, and the pressure is the difference between the operating pressure detection value and the stored pre-operating pressure reference value. According to the amount of change, according to the degree of blockage of the air supply passage or the exhaust passage estimated from the amount of pressure change, or the air volume of the air supply passage or the exhaust passage estimated from the amount of pressure change a control unit that controls the operation of the burner according to
an update processing unit that executes processing for updating the pre-actuation pressure reference value stored in the storage unit;
The update processing unit acquires a pre-operation pressure detection value that is a pressure value detected by the pressure sensor in a stopped state before the operation of the fan is started, and determines whether the pre-operation pressure detection value is included in a predetermined range. If the pre-actuation pressure detection value is not included in the predetermined range, the pre-actuation pressure reference value stored in the storage unit is not updated, and the pre-actuation pressure detection value is The forced feeding system is configured to update the pre-actuation pressure reference value stored in the storage unit in accordance with at least the pre-actuation pressure detection value when the pre-actuation pressure detection value is included in the predetermined range. Exhaust type combustion device. In the forced exhaust combustion apparatus according to claim 1,
The update processing unit is configured to store the pre-actuation pressure detection value as a setting pressure detection value for newly setting the predetermined range when the pre-actuation pressure detection value is included in the predetermined range. In addition, the predetermined range to be compared with the pre-operation pressure detection value acquired in the stopped state before the start of operation of the blower is a range centered on an average value of the plurality of setting pressure detection values stored in the past. A forced supply and exhaust type combustion device characterized in that it is configured to be set to 3. In the forced supply and exhaust type combustion device according to claim 1 or 2,
The update processing unit is configured to, when updating the pre-actuation pressure reference value stored in the storage unit, update the pre-actuation pressure reference value to the pre-actuation pressure detection value. A forced air supply and exhaust type combustion device. Combustion air is supplied to a burner through an air supply passage by operation of an air blower, and combustion exhaust gas generated by combustion operation of the burner is exhausted through an exhaust passage.
a pressure sensor that detects a differential pressure between an upstream side and a downstream side of an orifice provided in the air supply path or the exhaust path;
a storage unit that stores and holds a pre-operation pressure reference value that is a reference value of the pressure value detected by the pressure sensor in a stopped state before the operation of the blower is started;
During the operation of the blower, an operating pressure detection value, which is the pressure value detected by the pressure sensor, is obtained, and the pressure is the difference between the operating pressure detection value and the stored pre-operating pressure reference value. According to the amount of change, according to the degree of blockage of the air supply passage or the exhaust passage estimated from the amount of pressure change, or the air volume of the air supply passage or the exhaust passage estimated from the amount of pressure change a control unit that controls the operation of the burner according to
an update processing unit that executes processing for updating the pre-actuation pressure reference value stored in the storage unit;
The update processing unit acquires a pre-operation pressure detection value that is a pressure value detected by the pressure sensor in a stopped state before the operation of the fan is started, and determines whether the pre-operation pressure detection value is included in a predetermined range. If the pre-actuation pressure detection value is not included in the predetermined range, the number of consecutive occurrences of the event not being included in the predetermined range is counted, and the counted number of times is a predetermined number. When the counted number of times has been reached, the pre-actuation pressure reference value stored in the storage unit is updated according to at least the pre-actuation pressure detection value, and when the counted number of times is less than the predetermined number of times 2. A forced air supply/exhaust type combustion apparatus, wherein the pre-operation pressure reference value stored in said storage unit is not updated. In the forced exhaust combustion apparatus according to claim 4,
The forced supply/exhaust combustion apparatus, wherein the update processing unit is configured to set the predetermined range to a range centered on the pre-operation pressure reference value stored in the storage unit. . In the forced supply and exhaust type combustion device according to claim 4 or 5,
The update processing unit stores the pre-actuation pressure detection value as an update pressure detection value for updating the pre-actuation pressure reference value when the pre-actuation pressure detection value is not within a predetermined range. and when updating the pre-actuation pressure reference value stored in the storage unit in response to the counted number reaching the predetermined number of times, the pre-actuation pressure reference value is The forced air supply/exhaust combustion apparatus is configured to update the stored pre-actuation pressure detection value to an average value at each of the predetermined times.

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