JP2017116177A - Gas burning appliance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce aged deterioration due to heat in peripheral parts of a transistor, in a gas burning appliance including the transistor for supplying a driving current to a proportional valve.SOLUTION: A gas combustion appliance includes: a combustion part 13 which can switch and control the size of a combustion region to a plurality of capacity levels; a proportional valve 16 which adjusts the flow rate of fuel gas to the combustion part 13; and a control board which controls the number of capacity levels and the drive current of the proportional valve 16 so as to obtain the required combustion heat quantity. In the gas combustion appliance provided with the transistor Q1 through which the drive current of the proportional valve 16 flows, on the control board, when the control board controls the drive current within a range X in which the number of capability levels can be switched, while maintaining the combustion heat quantity, and the loss of the transistor Q1 is equal to or larger than a predetermined value, the magnitude of the drive current is changed and controlled so that the loss of the transistor Q1 is less than the predetermined value, and the number of capability stages of the combustion part 13 is changed and controlled so as to maintain the combustion heat quantity before and after the change.SELECTED DRAWING: Figure 2

Description

  The present invention relates to gas combustion equipment such as a gas heat source for heating and a gas water heater.

  For example, as disclosed in Patent Document 1 below, in a gas combustion apparatus such as a gas water heater, a constant current circuit is used to stably supply a drive current corresponding to a control opening degree command to a gas proportional valve. Is used to control the drive current, and the drive current is directly controlled by the transistor (Tr1) constituting the constant current circuit.

Japanese Patent No. 3571847

  In the transistor of the constant current circuit, the drive current of the proportional valve flows directly between the collector and the emitter, but the drive current of the proportional valve is relatively large, about several tens mA to several tens of mA, so that the loss of the transistor The calorific value may be relatively large depending on the characteristics.

  Even if the amount of heat generated has little effect on the operation of the transistor or its peripheral circuit itself, it is concerned that it may accelerate the aging of peripheral parts such as resin potting on the substrate, thereby shortening the product life. It is ideal to use transistors with as little loss as possible, but there are limited transistor options that meet the required characteristics and are available at a realistic price. When a transistor is selected giving priority to characteristics and cost, the operation may be continued for a long time under operating conditions that are not preferable for peripheral parts.

  For example, the applicant of the present application switches the size of the combustion area to any one of a plurality of capacity stages according to the heating load (required combustion capacity) of the hot water heating terminal in Japanese Patent Application Laid-Open No. 2014-66497, Discloses a heat source unit for heating that controls the opening of the gas proportional valve. Depending on the heating load, the heating operation is constantly performed for several tens of minutes with a small number of capacity stages and a relatively large opening of the proportional valve. May be performed.

  Since the opening of the proportional valve is proportional to the magnitude of the driving current supplied to the proportional valve, the driving current increases when the opening of the proportional valve is large. For example, the driving current of about 80 mA is several tens of minutes. It may continue to flow. As a characteristic of loss with respect to the collector-emitter current of the selected transistor, for example, if there is a loss peak at around 80 mA, the amount of heat generated by the transistor is maximized in the above case, and the deterioration of peripheral parts is promoted. End up.

  Therefore, an object of the present invention is to reduce the aging deterioration due to heat of peripheral parts of a transistor in a gas combustion apparatus including a transistor that supplies a drive current to a proportional valve.

  In order to achieve the above object, the present invention has taken the following technical means.

  That is, the present invention provides a combustion section configured to be capable of switching the size of the combustion region to a plurality of capacity stages, and provided in the middle of the fuel gas flow path to the combustion section, and is opened according to the drive current. A proportional valve whose degree of adjustment is adjusted, and a control unit that controls the number of capacity stages of the combustion unit so as to obtain the required amount of combustion heat, and that controls the drive current of the proportional valve, the control unit comprising the proportional valve In the gas combustion device having the transistor through which the drive current flows, the control unit is within a range in which the number of capacity stages can be switched while maintaining the amount of combustion heat, and the loss of the transistor is a predetermined value or more. And controlling the magnitude of the drive current so that the loss of the transistor is less than a predetermined value, and maintaining the amount of combustion heat before and after the change. Is characterized in that the changing control capability number of parts (Claim 1).

  According to the gas combustion apparatus of the present invention, the heat generation amount of the transistor can be reduced while maintaining the heat of combustion, so that the peripheral parts of the transistor, for example, potting agents, etc. It can be avoided that the deterioration is accelerated by the heat generation of the transistor. Further, it is possible to eliminate or simplify the radiator of the transistor, thereby reducing the cost.

  Further, the present invention provides a combustion section, a proportional valve provided in the middle of the fuel gas flow path to the combustion section and having an opening degree adjusted according to the drive current, and the above-described combustion heat quantity so as to obtain the required amount of combustion heat. A control unit that controls the drive current of the proportional valve, and the control unit is a gas combustion apparatus having a transistor through which the drive current of the proportional valve flows. When the drive current is controlled within a range, the magnitude of the drive current is controlled to be changed even if the required combustion heat quantity is not obtained so that the loss of the transistor is less than a predetermined value. (Claim 2).

  According to the gas combustion device of the present invention, since the amount of heat generated by the transistor can be reduced, it is possible to avoid the deterioration of the peripheral parts of the transistor, for example, potting agent, over time due to the heat generated by the transistor. Further, it is possible to eliminate or simplify the radiator of the transistor, thereby reducing the cost. The configuration of claim 2 can be preferably implemented particularly in a gas combustion appliance for heating in which the required amount of combustion heat is determined according to the heating load, and temporarily operates below the required amount of combustion heat in the case of heating operation. Even if the control is performed, the room temperature is not affected immediately, so the drive current is controlled within a relatively low range of the transistor loss until the temperature of the transistor and its surrounding parts decreases, and then based on the required combustion heat quantity What is necessary is just to return to control of drive current.

  In the gas combustion apparatus of the present invention, the control unit performs the change control of the magnitude of the drive current when the drive current is controlled within a range in which the loss of the transistor is a predetermined value or more. The driving current is controlled within a range in which the loss of the current becomes equal to or greater than a predetermined value until it is continued for a predetermined time (claim 3). According to this, even if the drive current flows for a short time within the range where the transistor loss is relatively high, the total heat generation does not adversely affect the peripheral parts. By not performing the control, it is possible to continue the drive current control in accordance with the required amount of combustion heat, giving priority to combustion efficiency and noise countermeasures.

  Further, in the gas combustion device of the present invention, the control unit performs a change control of the magnitude of the drive current when the drive current is controlled within a range in which the loss of the transistor is a predetermined value or more. It may be configured not to perform the operation until it is estimated that the ambient temperature of the transistor has become equal to or higher than a predetermined temperature due to heat generation of the transistor based on the driving current and the loss of the transistor. ). According to this, when it is not estimated that the ambient temperature of the transistor has exceeded the predetermined temperature, there is no adverse effect on the peripheral parts. In such a case, the drive current change control is not performed, so that the combustion efficiency and noise can be reduced. Drive current control corresponding to the required combustion heat quantity can be continued with priority on measures and the like.

  Specifically, the above estimation can be performed based on the control history data of the drive current of the proportional valve or the detection history data of the detected value of the actual drive current of the proportional valve. For example, data related to the loss of the transistor with respect to the drive current is stored in the control unit in advance, and the heat generation amount of the transistor within the latest predetermined time is calculated using the data, and the heat dissipation amount of the transistor and its peripheral parts is calculated. As a result, the ambient temperature of the transistor can be estimated from the difference between the heat generation amount and the heat dissipation amount.

  As described above, according to the gas combustion apparatus of the present invention, it is possible to reduce the aging of the peripheral parts of the transistor due to the heat generation of the transistor that supplies the drive current to the proportional valve.

It is a schematic block diagram of the gas heat source machine for heating which is a gas combustion apparatus which concerns on one Embodiment of this invention. It is a graph for demonstrating the combustion capacity switching control in the same gas combustion apparatus. It is a schematic circuit diagram of the proportional valve drive circuit of the gas combustion apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a hot water circulation heating device using a gas heat source device 1 as a gas combustion device according to an embodiment of the present invention, and the heating device includes a gas heat source device 1 having a heating operation function, Mainly composed of a floor heating terminal 2 as a low temperature heating terminal and a high temperature heating terminal 3. In FIG. 1, only the main part of the heating operation function of the heat source device 1 is illustrated, but as the heat source device 1, a composite heat source device having functions of hot water supply / heating and reheating can be suitably used.

  The heat source machine 1 includes a combustion can body 11 and a warm water circulation circuit 12 for heating. Inside the can 11, a combustion device 13 (combustion unit) divided into a plurality of combustion regions 13 a and 13 b is provided. A blower fan (not shown) that supplies combustion air to the combustion device 13 is disposed below the combustion device 13.

  Each of the combustion regions 13a and 13b of the combustion device 13 is formed by a plurality of burners, and in the illustrated example, two combustion regions are illustrated, but may be divided into three or more combustion regions. . A gas supply pipe 14 for supplying gas as a combustion fuel from the fuel gas supply source side is connected to each of the combustion regions 13a and 13b. The gas supply pipe 14 is provided with an original gas solenoid valve 15 as a main plug and a gas proportional valve 16 for adjusting the gas supply amount in order from the fuel gas supply source side. The gas supply pipe 14 is branched for each of the combustion regions 13a and 13b on the downstream side of the gas proportional valve 16, and gas is supplied to the first combustion region 13a via the first capacity switching valve 17a. Gas is supplied to the combustion region 13b through the second capacity switching valve 17b.

  As a result, as shown in FIG. 2, the size of the fuel region is reduced to a plurality of capacity stages (in the illustrated example, only the first combustion region 13a is controlled) by selective opening and closing control of the first and second capability switching valves 17a and 17b. 1 stage to burn, 2 stages to burn only the second combustion region 13b, and 3 stages to burn the first and second combustion regions 13a and 13b), and is proportional to the gas. By adjusting the supply amount of the fuel gas at each capability stage number by opening degree control (drive current control) of the valve 16, the amount of combustion heat (number of hot water supply) can be changed and controlled within a predetermined range for each capability stage number. Yes. The combustion heat quantity overlaps the large combustion side area X of the capacity stage number on the lower side of the adjacent stage number and the small combustion side area of the capacity stage on the upper stage side. From the minimum combustion heat quantity (for example, No. 3 in terms of the number of hot water supply) that burns only the first combustion area 13a with the minimum combustion capacity of the burner, the maximum combustion that burns all of the plurality of combustion areas 13a and 13b with the maximum combustion capacity It is possible to change and adjust continuously up to the amount of heat (for example, No. 10 in terms of the number of hot water supply).

  A heat exchanger 18 is disposed in the upper part of the can 11. Although not shown in the figure, a primary heat exchanger that recovers sensible heat of the combustion gas generated by burning fuel in the combustion device 13, and thermal energy of the combustion gas that cannot be recovered in the primary heat exchanger, that is, It can also be configured as a latent heat recovery type high efficiency heat source device provided with a secondary heat exchanger for recovering latent heat.

  The heating circuit 12 forms a circulation path of hot water serving as a heat medium between the high-temperature heating terminal 3 and the low-temperature heating terminal 2, and the heat exchanger 18 that heats the hot water circulating in the circulation path; The high-temperature hot water going to the high-temperature heating terminal 3 for supplying the high-temperature hot water heated to a predetermined temperature (for example, about 80 ° C.) by the heat exchanger 18 and the hot water after radiating heat from the high-temperature heating terminal 3 A heating return pipe 12b for returning to the heat exchanger 18 and a low temperature (for example, about 60 ° C.) before being heated from the heating return pipe 12b by being branched from the heating return pipe 12b on the upstream side of the heat exchanger 18. The main configuration includes a low-temperature heating forward pipe 12c for supplying hot water to the low-temperature heating terminal 2, and a bypass pipe 12d for bypassing a part of the high-temperature hot water heated by the heat exchanger 18 to the heating return pipe 12b. Has been.

  Further, an expansion tank 19 and a heating circulation pump P provided on the downstream side of the tank 19 are interposed in the middle of the heating return pipe 12 b. In the illustrated example, the low-temperature heating forward pipe 12c is branched from the heating return pipe 12b on the downstream side of the heating circulation pump P. The bypass pipe 12d is branched from the high-temperature heating forward pipe 12a and joined to the heating return pipe 12b on the upstream side of the expansion tank 19 and the heating circulation pump P. The expansion tank 19 is supplied with low-temperature hot water that is a mixture of low-temperature water returned from the heating ends 2 and 3 and high-temperature hot water flowing through the bypass pipe 12d.

  Control targets such as the blower fan, capacity switching valves 17a and 17b, the original gas solenoid valve 15, the gas proportional valve 16, and the heating circulation pump P are controlled by the control unit (control board) and are required during the heating operation. The required amount of combustion heat is determined based on the heating capacity (hot water supply capacity), and the number of capacity stages of the combustion device 13 and the opening degree of the proportional valve 16 are controlled so that the required amount of combustion heat is obtained. The opening degree of the proportional valve 16 is adjusted according to the supplied drive current. In this embodiment, the control unit includes a constant current circuit (proportional valve drive circuit) that supplies the drive current to the proportional valve. Thus, the drive current is directly controlled.

  That is, as shown in FIG. 3, the control unit supplies the proportional valve 16 with a drive current corresponding to the opening signal output from the microprocessor 20 as the control center and the proportional valve opening signal output port of the microprocessor 20. And a constant current circuit 21 to be supplied. In the illustrated example, a driving current monitoring circuit 30 that outputs a monitoring voltage signal corresponding to the current value of the driving current to the monitoring signal input port of the microprocessor 20 is also provided.

The constant current circuit 21 includes a voltage follower 22 that performs impedance conversion of the opening signal, a voltage dividing circuit 23 that divides the converted opening signal and outputs a reference voltage, and the reference voltage is input to a non-inverting input terminal. And an pnp transistor Q1 connected to the output of the operational amplifier 24. The base of the transistor Q1 is connected to the output of the operational amplifier 24, and the collector of the transistor Q1 is connected to the proportional valve 16 and the inverting input terminal of the operational amplifier 24 to form a negative feedback circuit. the voltage becomes equal to the reference voltage, constant current I _{L =} V L _/ R _L based on the voltage across V _L of the proportional valve 16 and its resistance component R _L is supplied to the proportional valve 16 as the drive current. The constant current I _L, the collector of the transistor Q1 - becomes emitter current is outputted from the emitter.

Driving current monitoring circuit 30 includes a load resistor R1 connected to the emitter of the transistor Q1, the drive current I _L is supplied to the load resistor R1, a voltage corresponding to the drive current I _L (I _L × R1) occurs in the load resistance R1. The voltage of the load resistor R1 is divided by the voltage dividing circuit 31 and input to the monitoring signal input port of the microprocessor 20 as a monitoring voltage signal, and the current value of the drive current of the proportional valve 16 is monitored based on the monitoring voltage signal. It is possible.

The resistance component _RL of the proportional valve 1 is, for example, several tens of ohms to several hundreds ohms, the resistance value of the load resistance R1 is, for example, several tens of ohms to several hundreds ohms, and the resistors R2 and R3 constituting the voltage dividing circuit 31 are For example, it can be several hundred kΩ. The transistor Q1 has a loss characteristic that has a loss peak when the collector-emitter current is 60 to 100 mA and generates the largest amount of heat.

  In the present embodiment, the microprocessor 20 of the control unit drives the proportional valve 16 when controlling the number of stages of the combustion device 13 and the drive current of the proportional valve 16 so as to obtain the required amount of combustion heat. If the current is continuously controlled for a predetermined time (for example, about 10 to 20 minutes) at the point A within the range indicated by the region X in FIG. 2, for example, the heat generated by the transistor Q1 based on the drive current and the loss of the transistor Q1. It is estimated that the ambient temperature of the transistor Q1 has become equal to or higher than the predetermined temperature, and the number of capacity stages of the combustion device 13 is increased by one, and the drive current is changed and controlled up to point B so as to maintain the combustion heat quantity before and after that. Control configured. That is, in this embodiment, when the loss of the transistor Q1 when the drive current is 60 mA is a predetermined value L, the drive current is continuously controlled within a range X in which the loss of the transistor Q1 is equal to or greater than the predetermined value L. If so, the magnitude of the drive current is controlled so that the loss of the transistor Q1 is less than the predetermined value L.

  Also, according to various situations, as shown as a transition from point A to point C in FIG. 2, only the drive current of proportional valve 16 is changed to a region where the loss of transistor Q1 is small, without changing the number of capacity stages. By controlling, the amount of heat generated by the transistor Q1 can be reduced by temporarily reducing the amount of combustion heat.

  Only one of the change control from the A point to the B point and the change control from the A point to the C point can be implemented as a control method of the microprocessor 20, or various types can be implemented after both are implemented. It can also be configured to select which change control is to be performed according to operating conditions and the like.

  The range indicated by the region W in FIG. 2 is a range in which the number of capacity stages can be switched while maintaining the amount of combustion heat, and is the range in which the loss of the transistor Q1 is the highest. When the drive current in the region W flows through the transistor Q1, the heat generation of the transistor promotes aged deterioration of peripheral parts such as circuit parts and potting around the transistor. However, according to the present embodiment, a long time exceeding a predetermined time. By avoiding that the heat generation amount of the transistor Q1 is continuously large over time, it is possible to prevent the peripheral parts of the transistor Q1 from being accelerated by heat and to reduce the cost by eliminating or simplifying the heat dissipation plate of the transistor Q1. You can also.

  The present invention is not limited to the above-described embodiment, and the design can be changed as appropriate. For example, in the above embodiment, it is estimated that the ambient temperature of the transistor Q1 has become equal to or higher than the predetermined temperature because the drive current is continuously controlled within the range indicated by the region X for a predetermined time. For example, data related to the loss of the transistor Q1 with respect to the drive current is stored in the microprocessor 20 in advance, and the amount of heat generated by the transistor Q1 within the most recent predetermined time is calculated using the data. The heat dissipation amount of the transistor Q1 and its peripheral parts can also be calculated or estimated, and the ambient temperature of the transistor can be estimated from the difference between the heat generation amount and the heat dissipation amount.

  Moreover, although the said embodiment demonstrated as control during heating operation, the same control can be performed also during hot water supply operation of a water heater.

13 Combustion section 16 Proportional valve Q1 Transistor

Claims (4)

A combustor configured to be able to switch and control the size of the combustion region to a plurality of capacity stages, and a proportionality that is provided in the middle of the fuel gas flow path to the combustor and whose opening is adjusted according to the drive current A valve and a control unit for controlling the number of stages of the combustion unit so as to obtain a required amount of combustion heat and for controlling the drive current of the proportional valve, the control unit being a transistor through which the drive current of the proportional valve flows In gas combustion equipment having
When the control unit controls the drive current within a range in which the number of capacity stages can be switched while maintaining a combustion heat amount, and the loss of the transistor is equal to or greater than a predetermined value, The drive current magnitude is changed and controlled so that the loss of the transistor is less than a predetermined value, and the capacity stage number of the combustion section is changed and controlled so that the amount of combustion heat is maintained before and after the change. Gas burning equipment. A combustor, a proportional valve provided in the middle of the fuel gas flow path to the combustor, the opening of which is adjusted according to the drive current, and the drive current of the proportional valve so as to obtain the required amount of combustion heat. A control unit for controlling, in the gas combustion equipment having a transistor through which the drive current of the proportional valve flows,
The control unit is configured to control the driving current within a range in which the loss of the transistor is equal to or greater than a predetermined value, so that the loss of the transistor is less than the predetermined value even if the required combustion heat amount is not obtained. A gas combustion apparatus characterized by changing and controlling the magnitude of a drive current.   3. The gas combustion device according to claim 1, wherein the control unit controls the change in the magnitude of the drive current when the drive current is controlled within a range in which the loss of the transistor is a predetermined value or more. The gas combustion device is configured not to perform the control of the drive current within a range in which the loss of the transistor is equal to or greater than a predetermined value until the transistor is maintained for a predetermined time.   3. The gas combustion device according to claim 1, wherein the control unit controls the change in the magnitude of the drive current when the drive current is controlled within a range in which the loss of the transistor is a predetermined value or more. The gas combustion device is configured not to perform the operation until it is estimated that the ambient temperature of the transistor has become equal to or higher than a predetermined temperature due to the heat generation of the transistor based on the drive current and the loss of the transistor. .

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