JPS6096827A - Combustion control circuit - Google Patents

Abstract

PURPOSE:To provide a combustion control circuit which is well suited to a mass- production, by freely switching an upper limit current flowing to the coil of solenoid proportional valve in a plurality of high and low steps by means of capacity switching circuit. CONSTITUTION:Where it is desirable to use a No. 16 type water-heater as a No. 13 type, two switches 17, 18 of capacity switching circuit 13 are closed to control an upper limit current flowing to the coil 2a of solenoid proportional valve 2 at a level, for example, I1 which is substantially lower than a coil current IM providing the burner 1 of No. 16 type water-heater with a maximum rated combustion quantity QM. This permits the solenoid proportional valve 2 to make its maximum opening amount smaller than a maximum rated opening amount needed for use as the No. 16 gas-heater. Thus, the maximum combustion quantity of burner 1 can be reduced to a level Q1 which is smaller than its maximum rated combustion quantity QM, whereby allowing for the use of No. 16 capacity type gas water-heater as a No. 13 type heater. The combustion control circuit can thus be well suited for a mass-production.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a combustion control circuit that enables full switching of the capacity of a combustor, such as a water heater, equipped with an electromagnetic proportional valve.

As a conventional combustion control circuit, a control circuit built into one board changes the current flowing through the coil of an electromagnetic proportional valve installed in the fuel supply path according to changes in load.
It is known that the combustion amount of the burner is controlled by changing the opening degree of the proportional valve, but in combustors with different capacities, it is common to use a dedicated burner 4 with a corresponding maximum rated combustion amount. Therefore, a dedicated circuit corresponding to the burner is also used for the control circuit, making it difficult to mass-produce.

The purpose of the present invention is to provide a combustion control circuit with excellent mass productivity, in which the current flowing through the coil of an electromagnetic proportional valve installed in the fuel supply path is changed in accordance with changes in load. , in which the combustion amount of the burner is controlled by fully changing the opening of the proportional valve, a capacity switching circuit is provided to fully control the upper limit current value of the coil, and the capacity switching circuit controls the maximum rated combustion of the burner. The present invention is characterized in that the upper limit current value can be freely switched between high and low levels within a range below the current value for supplying R.

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an embodiment in which the present invention is applied to a gas water heater. (4j is a heat exchanger, (5) is a temperature sensing element consisting of a thermistor facing into the hot water supply pipe on the downstream side of the heat exchanger (4), (6) shows all the control circuits of the present invention that control the current flowing through the coil of the proportional valve (2).

Next, the specific configuration of the control circuit (6) will be explained based on FIG. The bridge circuit (8) incorporates a temperature sensing element (5) for detecting the hot water temperature and a variable resistor (7) for setting the hot water temperature that is linked to a temperature control knob (not shown). The deviation between the hot water temperature and the set temperature is detected by the potential difference between the connection point A and the connection point B, and the potential difference, that is, the voltage, is operationally amplified by the operational amplifier (9) and then sent to the voltage divider circuit. The level is adjusted from yc and inputted to the base of transistor aυ, and the current is generated at the collector side of transistor Ov in accordance with the difference between 77Iiii degrees of hot water and the set temperature. The current flowing to the collector side is passed through the coil (2aJ) of the electromagnetic proportional valve (2) interposed in the fuel supply path (3) to the burner (1) to control the opening degree of the proportional valve (2). As shown in Figure 6, the combustion amount of the nocuna (1) is proportionally controlled up to the maximum rated combustion ff1Qh0.In Figure 2, O2 represents the current flowing through the coil (2a). 1 shows an operational amplifier that compensates for disturbances.

Although the above configuration is not particularly different from the configuration of the conventional circuit, the present invention is arranged in the fuel supply path (3) to control the upper limit current value of the coil (2a) of the 7'C electromagnetic proportional valve (2). A capacity switching circuit (131) is provided to control the capacity switching circuit (1).The capacity switching circuit (131) is capable of freely switching between high and low levels of the upper limit current value within a range of 1 or less current value that supplies the maximum rated combustion amount of the burner +11 by means of a moat. To explain in detail what is shown in the figure, a capacity switching circuit Q31' is incorporated on the ground side of the voltage dividing point 0 of the voltage dividing circuit (10),
This ability switching circuit α3) consists of five resistors a4 connected in series.
J(151ae), and two of them are connected in parallel with each switch 71081, and by switching this capacity switching circuit (131), the potential at the voltage dividing point 0 can be freely switched to 5 levels of high and low. To explain more specifically, both switches (17)a
If gIi is closed, the resistor side and the resistor (15) are short-circuited, and the potential at the voltage dividing point 0 can be made the lowest.If only switch 07) is closed, the 1-resistance 0 slope is short-circuited. , the potential at the voltage dividing point 0 can be sieved more than when both switches ←7)<181 are closed, and both switches αη(()9
By switching the potential of the voltage dividing point 0 into three high and low levels, the maximum base potential of the transistor (ill) can be set to the highest level.
It can be changed in stages, and in the end, an electromagnetic proportional valve (2
) upper limit current value 'ff of coil (2a): S burner (1
), the maximum rated combustion amount Qy k is 3 levels high and low in the range below the supplied current value, as shown in Figure 5. Engineering 2,1M
It can be switched to three stages.

1 In the case shown in the second diagram, a 7'c adjustment circuit a9 is incorporated in the non-grounded side of the voltage division point O of the voltage dividing circuit (101) in accordance with the type of gas, and this adjustment circuit Q1 has three mutually connected parallel resistors D C2'Z) and these resistors (2[I C!i
One selector switch (consisting of two resistors) to select lc+a, each resistor (20) (21) (2'lJ'e Switch the selector switch (c) for city gas, natural gas, and propane gas. By doing so, the potential at the partial pressure point 0 becomes a value corresponding to the gas type. (1) and control circuit (
6) 1 by simply switching the capacity switching circuit 03) without changing the sound level.
It can be changed to either a No. 5 gas water heater or a No. 113 gas water heater, and in more detail, it was used as a No. 13 gas water heater. ←Close both switches an (181) of 3) and open the solenoid proportional valve (2).
The maximum rated combustion RkQMk of the coil (of a No. 16 gas water heater) is considerably lower than the coil current value M supplied by the coil (for a No. 16 gas water heater). , should be regulated.

This allows the maximum rated opening of the solenoid proportional valve (2) to be smaller than the maximum rated opening of the gas water heater, which has a maximum opening of No. 116, and the maximum combustion amount of the burner (1) to the maximum rated twist Ii. ,
It is possible to make Ql smaller than foot QM, and the ability is 16.
You can use the No. 13 gas water heater by changing it to a No. 13 gas water heater.

Also, if you want to use it as a No. 16 gas water heater,
Both switches θ7 of the capacity switching circuit (13) According to the present invention, the fuel supply path is interposed,
The upper limit current value of the coil of the electromagnetic proportional valve and the capacity switching circuit can be freely switched between high and low levels in the range below the m flow value that supplies the burner's maximum rated combustion smoke, making it suitable for combustors with different capacities. The above-mentioned conventional circuit can also be applied by simply switching the upper limit current value of the coil using the capacity switching circuit, and requires a dedicated burner according to the capacity and a dedicated coil current control circuit corresponding to the burner. It has a superior effect on M productivity compared to .

[Brief explanation of the drawing]

Figure 1 shows 1F of a gas appliance to which the present invention is applied! An explanatory diagram showing llJ, Fig. 2 is a circuit diagram showing an example of non-invention, Fig. 3 is a diagram showing an example of non-invention.
The figure is a diagram showing the relationship between coil current value and combustion amount. (2) Solenoid proportional valve (2IL) Coil (3) Fuel supply path (131 Capacity switching circuit patent applicant Rinnai Corporation Company agent Kin Kita Toshi - (2 people outside of 1 degree)

Claims (1)

[Claims] In a device in which the current flowing through the coil of an electromagnetic proportional valve interposed in the fuel supply path is changed in accordance with changes in load, the opening degree of the proportional valve is changed, and the combustion amount of the burner is controlled. , a capacity switching circuit is provided to control the upper limit current value of the coil, and the capacity switching circuit sets the upper limit current value in multiple stages of high and low levels within a range below the current value that supplies the maximum rated burner amount of the burner. A combustion control circuit characterized by being switchable.