JPH01118064A - Hot water supplying device - Google Patents

Abstract

PURPOSE:To prevent a chattering action caused by a valve opening or a valve closing of a changing-over solenoid valve by a method wherein the changing-over solenoid valve is opened or closed only when a changing-over signal is outputted. CONSTITUTION:When a gas proportional control reaches near a maximum range of a semi-open capability control range, a full-open changing-over signal is outputted. When the full-open changing-over signal is outputted and the gas proportional control stays near a maximum range of a semi-open capability control range for a specified time after outputting a full-open changing-over signal, a gradual ignition current is supplied to a governor proportional valve 23, a changing-over valve 24 is turned ON and it is changed over to a full-open capability control range through a simultaneous combustion of the first and second burners 11a and 11b. When it reaches a minimum range of a full-open capability control range, it may output a semi-open changing- over signal. When a gas proportional control stays near a minimum range of a full- open capability control range for a specified time after outputting a semi-open changing-over signal, the changing-over valve 24 is turned OFF and an electric current for the governor proportional valve 23 is controlled by a gas proportional control of a semi-open capability control range through combustion only in the first burner 11a and then an amount of gas is automatically adjusted.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a hot water supply system that employs feedback control that automatically adjusts the amount of fuel supplied by calculating the required capacity based on the deviation between the set temperature and the hot water temperature. Concerned with vessels.

[Prior Art] Japanese Utility Model Publication No. 60-16843 discloses a first burner connected to a fuel supply path through a proportional valve, and a second burner connected to the proportional valve through a 1m switching valve. The half-open capacity control range Il is controlled by proportional control during half-open capacity operation by combustion of only the first burner, and the proportional control during full-open capacity operation by simultaneous combustion of the first burner and the second burner. A water heater is disclosed that is provided with a full-open capacity control range controlled by the control and an overlapping control range of a maximum range of half-open capacity control 60 range and a minimum range of full-open capacity control l range.

[Problem to be Solved by the Invention 1] However, in the water heater with the above configuration, when the maximum half-open capacity control range is reached and a switching signal is output, the switching solenoid valve is immediately opened and the half-open capacity control is abruptly started. Full capacity control from area I
When switching to the I range or when the minimum range of the full open capacity control range is reached and a switching signal is output, the switching solenoid valve is immediately closed and the full open capacity control range is suddenly switched from the full open capacity control range I to the half open capacity control range. In this way, when the switching signal is captured as an instantaneous value, a chattering phenomenon occurs in a device with a large heat capacity, such as a water heater, or a device with a delayed response, which may lead to poor control.

An object of the present invention is to provide a water heater that smoothly performs switching control between a half-open capacity control range and a full-open capacity control range II.

[Means for Solving the Problems] The water heater of the present invention includes a fuel supply amount control means for adjusting the amount of fuel supplied, and a first fuel supply path connected to the fuel supply path via the fuel supply amount control means. a burner, and a second burner connected to the fuel supply amount control means via a switching solenoid valve, and a heat exchanger that is provided above the burner and heats water passing through the burner; an output of water i&1ffl provided downstream of the heat exchanger and flowing out from the heat exchanger;
a hot water outlet temperature detection means for detecting the hot water outlet temperature, an operating means for setting the outlet hot water temperature to a desired set temperature, and a half-open capacity operation with combustion of only the first burner based on the deviation between the set temperature and the outlet hot water temperature; During half-open capacity operation controlled by proportional control, during full-open capacity operation by simultaneous combustion of the first burner and second burner, in full-open capacity control range II controlled by proportional control, and in half-open capacity control range a. An overlapping control range between the maximum range and the minimum range during full-open capacity operation is selected, and the switching solenoid valve is opened or closed according to these control m+ ranges, and the fuel supply amount is automatically adjusted. In a water heater equipped with a control circuit that performs feedback control, when the proportional control due to the feedback control reaches near the maximum range of the half-open capacity control range and a switching signal to the full-open capacity control range is output. Alternatively, if the switching signal to the half-open capability control region is output after the switching signal is delayed to near the minimum range of the full-open capability control region, the switching solenoid valve is opened only when the switching signal is output for a certain period of time. A valve or valve-closing configuration was adopted.

In the present invention, 174 half-open includes not only the whole 172 but also other partial amounts.

[Actions and Effects of the Invention] The water heater of the present invention has the following actions and effects due to the above configuration.

Based on the deviation between the set temperature and the hot water temperature, there is a half-open capacity control range controlled by proportional control during half-open capacity operation with combustion of only the first burner, and a half-open capacity control range controlled by simultaneous combustion of the first burner and the second burner. During full-open capacity operation, the full-open capacity control range controlled by proportional control and the overlapping control range of the maximum range of the half-open capacity control Il range and the minimum range of the full-open capacity control wJ range are selected, and the control range is controlled according to these control ranges. In addition to opening or closing the switching solenoid valve, proportional control by feedback control that automatically adjusts the fuel supply amount reaches the maximum range of the half-open capacity control range and sends a switching signal to the full-open capacity control range. The switching solenoid valve opens or closes only when the switching signal is output for a certain period of time, when the switching signal is output to the half-open capacity control range when it reaches the minimum range of full-open capacity control 1, or when the switching signal to the half-open capacity control range is output. By closing the valve, the switching solenoid valve opens,
Chattering due to valve closure can be prevented, resulting in safe combustion conditions.
and smooth half-open capacity control range and full-open capacity control range
Switching control with lU can be performed.

[Embodiment] In the present invention, an embodiment of a gas combustion type water heater using fuel gas as fuel will be described with reference to the drawings.

FIG. 1 shows a gas combustion type water heater employing an embodiment of the present invention.

A combustor case 10 is provided in the water heater case 2 of the gas combustion water heater 1, and a first burner that burns fuel gas supplied through a gas supply pipe 20, which is a fuel supply path, is provided inside the combustor case 10. A double gas burner 11 consisting of a burner 11a and a second burner 11b is provided. Also,
The combustor case 10 is equipped with a combustion fan 12 using a three-phase Y-connected Glacis DC motor, and the gas burner 11 receives combustion air supplied by the fan 12 and fuel supplied from the gas supply pipe 20. The combustor is a forced air type combustor that burns with gas, and the combustion gas generated by combustion is exhausted to the outside from the exhaust port 3.

A heat exchanger 13 connected to a water supply pipe 30 is provided above the combustion case 10, and water passing through the interior is heated by the flame generated by the gas burner 11 and the heat of the combustion gas. Furthermore, the gas burner 11 inside the combustor case 10
A sparker 14, which is an ignition device, and a flame rod 15, which is a flame detection means, are provided near the ignition device.

The gas supply pipe 20 includes a source solenoid valve 21 that allows fuel gas to pass through when energized from the upstream side, a main solenoid valve 22, and a fuel gas supply! A governor-type gas proportional valve (hereinafter referred to as governor proportional valve) 23, which is a fuel supply control means that adjusts the amount of gas (hereinafter referred to as gas amount) by controlling the supply pressure, and a second burner 11
A switching electromagnetic valve (hereinafter abbreviated as a switching valve) 24 is provided to cut off fuel gas to b depending on the usage state, and supplies fuel gas to the sburner 11 described above.

A drain plug 32 equipped with a water filter 31 is provided at the most upstream portion of the water supply pipe 30, and a heat exchanger 13 is provided downstream of the drain plug 32.
A water volume proportional adjustment valve 33 using a geared motor is provided to adjust the amount of water flowing into the tank.
A potentiometer 34 is provided to detect the opening degree.

The temperature of the water whose inflow amount has been adjusted by the water mother proportional adjustment valve 33 is detected by an inlet water temperature thermistor 35, which is an inlet water temperature detection means provided immediately downstream, and further downstream, a water mother sensor 36, which is an inlet water temperature detection means. The amount of water entering is detected and sent to the heat exchanger 13 through the water supply pipe 30.

The water supply pipe 30 on the downstream side of the heat exchanger 13 is provided with a hot water temperature thermistor 38, which is a hot water temperature detection means for detecting the temperature of heated water. A stopper (not shown) is provided.

The water heater 1 having the above configuration is controlled by a control device 50.

As shown in FIG. 2, the control 11 device 50 includes a control circuit 60 connected to a power cord 51 connected to a wiring outlet, and a main controller 54 and a sub-controller 54a for remotely controlling the water heater 1. A terminal for connection and a gas type changeover switch 55 that is set according to the type of fuel gas are provided.

As for the type of fuel, gaseous fuels such as LP gas, city gas 13A1 city gas 6C, etc. are selectively switched by the gas type changeover switch 55.

Main controller 54 and sub controller 54a
1 is a temperature setting means operated by the user, and in this embodiment, a main controller 54 is provided close to the water heater 1, and a sub-controller 54a is provided at a hot water supply location such as a bathroom. In addition, the main controller 54 and the sub-controller 54a are connected to each operation switch 5.
6.56a and water temperature setting switch 57 for setting output II
．． 57a are provided.

The dust control circuit 60 includes a microcomputer (hereinafter referred to as CP).
There are a sparker circuit 71, a fan drive circuit 72, a proportional valve control circuit 73, a geared motor drive circuit 14, a position detection circuit 15, and a water amount detection circuit 76 centered around the CPU 70 (referred to as U), and these circuits are controlled by the CPU 70. Predetermined control is performed.

The fan drive circuit 72 rotates the fan 12 according to the combustion capacity such as the set temperature, detects the rotation speed using a Hall IC provided in a three-phase Y-connected brushless DC motor, and sends a detection signal to the CPU 70. send to

The proportional valve control circuit 73 controls the amount of current applied to the governor proportional valve 23 in order to adjust the amount of fuel gas supplied so that combustion in the gas burner 11 is performed at a desired air-fuel ratio. ) is a circuit that performs control based on a proportional control constant corresponding to The proportional valve control circuit 73 is a semi-fixed volume that proportionally controls the maximum value of the current to the governor proportional valve 23 in order to correct errors due to variations in the water heater 1 and pressure loss due to gas type to obtain an appropriate gas pressure. It is equipped with

The geared motor drive circuit 14 is a circuit that drives the geared motor of the permanent proportional adjustment valve 33 for regulating the amount of water flowing into the heat exchanger 13, and does not operate when the power is OFF, but when the power is 0'N, the sub Regardless of whether the operation switch 56a of the controller 54a is ON or OFF, it is set to the position of the previous set temperature, and from that position it is initially set to a position corresponding to the reference temperature.

The position detection circuit 75 is a circuit for analyzing the signal from the potentiometer 34 provided in the water m proportional adjustment valve 33 to detect its opening.
Accurate control is achieved by using only the electrically effective portion of the entire rotation angle of the potentiometer 34 where changes in rotation appear as changes in resistance, and by reading the detected resistance value directly as the rotation angle. There is.

The water amount detection circuit 76 detects the incoming water temperature based on the rotational speed signal of the water amount sensor 36. In this embodiment, two new methods are detected based on the rise timing and fall timing of the pulse signal from the water amount sensor 36. By obtaining a pulse signal, the pulse repetition period is shortened and the pulse width is increased to reduce errors in F/■ conversion.

The CPU 7G has a memory function that stores the reference temperature that is set in advance when the water heater 1 is assembled or shipped, and the type of fuel gas to be used, and the main controller 5.
4 and the sub-controller 54a;
Sequence control that controls the operating order and timing of each of the above circuits, Feedforward control'a (hereinafter referred to as FF control) that controls the combustion amount and water input amount based on the input water temperature and set temperature as capacity control, and Output hot water temperature Automatic adjustment of gas farm based on 0N1OFF of switching valve 24, fan 12
Combustion m and water inflow amount such as wind 1i1 clause on proportional integral side @
(hereinafter referred to as PI sub-control), feedback control (hereinafter referred to as FB!1ItLD), and FF! l1tll and F
BI! It performs switching control to switch between I and III, and also has safety functions.

The determination function is a part that analyzes pulse signals in order to perform control according to the respective setting states of the main controller 54 and the sub-controller 54a connected to the terminals 61 and 62 of the control circuit 60, respectively.
1 and terminal 62 are wire-saving two-wire terminals that can supply electricity to the main controller 54 and sub-controller 54a.

In the sequence control, when a water supply signal based on the water temperature sensor 36 is obtained by the user opening the hot water tap, the fan 12 is activated, and after a predetermined period of purging is performed, the ignition operation is performed. Ignition operation is original 1! The magnetic valve 21, the main solenoid valve 22, the governor proportional valve 23, and the sparker 14 are energized at the same time, and after ignition is detected, the combustion amount capacity is calculated and combustion starts according to the setting.

The sparker 14 is activated not only at the start of use, but also in the following cases where a misfire may occur during use, i.e., when the switching valve 24 is in the open state due to capacity control associated with the use of the dual gas burner 11. This is also carried out when the set temperature is changed and the current to the governor proportional valve 23 is reduced by, for example, 50% due to a change in the rotation speed of the fan 12.
Each operates for a predetermined time.

On the other hand, when a water flow signal is detected based on the water flow sensor 36, the combustion amount calculation starts simultaneously based on the inlet water temperature thermistor 35, but if the water temperature when water is not flowing through the water supply pipe 30 is read, the water temperature is correct. Therefore, in this embodiment, the water temperature is read by the inlet water temperature thermistor 35 after the water flow signal is detected, and the water temperature at that time is used as the water temperature data.

In the capacity control, FF control and FB (PI) control that detects the hot water temperature and corrects the combustion amount and water input m are performed.

The FF control uses a calculated value Q of the required capacity calculated from the humidity set by the main controller 54 and the sub-controller 54a, incoming water temperature, and amount of incoming water, and a calculated value q of the required capacity calculated from the incoming water temperature, incoming water amount, and outlet hot water temperature. The most efficient combustion capacity is calculated from the above, and the fan 12, the governor proportional valve 23, the switching valve 24, and the water volume proportional adjustment valve 33 are controlled respectively, and the gas amount and water input amount are automatically adjusted.

FF control is a rapid heating capacity vi (controlled by gas proportional control during rapid heating that outputs a capacity larger than the required capacity Q).
Q+α) and the residual heat purge capacity range (Q-β) controlled by the gas proportional control during residual heat purge that outputs a capacity smaller than the required capacity Q, the fan 12 and the governor proportional valve 2
3. Control the switching valve 24 and the water volume proportional adjustment valve 33 to adjust the gas mass and water inflow volume to vJ.

Moreover, the rapid heating capacity range (Q+α) is the maximum range of the half-open capacity control range controlled by gas proportional control during half-open capacity operation by combustion of only the first burner 11a, and
It is limited to the overlapping control range with the minimum range of the full open capacity control range controlled by gas proportional control during full open capacity operation due to simultaneous combustion of burner a and the second burner 11b. In particular, in this embodiment, as shown in the graph showing the relationship between the opening degree and the full opening capacity of the governor proportional valve 23 in FIG. , when the switching valve 24 is in the closed state, there is a half-open capacity mt area work in which gas proportional control is performed at 178 to 1/2 of the full open capacity only with the first burner 11a, and when the switching valve 24 is in the open state, the first 174 at full capacity with burner 11a and second burner 11b.
~1 gas proportional control by full-open capacity @extinction■, and the overlapping control area■ between the maximum value of the half-open capacity control area (172 of full-open capacity) and the minimum 1 of the full-open capacity control area (174 of full-open capacity) is set.

By the FB sub-control, when the gas proportional control reaches the vicinity of the maximum range of the half-open capacity control range, the switching valve 24 is turned on (opened) while performing slow ignition control to switch to the full-open capacity control range (2). With FB sub-control, gas proportional control is in the full-open capacity control range ■
When reaching near the minimum range of Performs switching control.

As a safety function, if the hot water temperature reaches or exceeds the boiling point W1 temperature and continues for a predetermined time ta (e.g. 1 to 10 seconds), if continuous combustion continues for t7 (e.g. 40 to 120) minutes, or if no flame is detected. At times, each solenoid valve is closed and operation is stopped.

The operation of the control device 50 of the water heater 1 of this embodiment will be explained based on the operation flowcharts shown in FIGS. 3 to 8.

When installing the water heater 1 blank, the gas company or the distributor of the water heater 1 confirms the type of fuel gas to be used using the gas type selector switch 55, and also sets the reference temperature (40° C. in this example). (Sl). The selection of the fuel gas type and the setting of the reference temperature are not performed by the user of the water heater, and are stored in the memory function of the CPU 70, so they are stored in the CP tJ 70 regardless of whether the power is turned on or off. There is. However, when the set temperature is input by the user, the CPU 70 gives priority to the set temperature over the reference temperature and controls the water heater 1 so that the hot water temperature approaches the set temperature.

In order to use the water heater 1, the power cord 51 is connected to a wiring outlet and the power is turned on (S2).

The water mother proportional control valve 33 has a reference temperature (40°C in this embodiment).
It is determined whether or not the opening degree is initially set to a maximum amount of water inflow corresponding to the amount of water inflow (S3).

Here, the water mother proportional control valve 33 is controlled by the sub-controller 54.
Regardless of whether a is ON or OFF, the opening degree is set to the predetermined opening of the set temperature (or reference temperature) when the nursery dispenser 1 was used last time. However, with the geared motor that changes the opening degree of the water volume proportional adjustment valve 33, if you try to adjust the opening degree after inputting the set temperature, the movement time will be several seconds, which may eat into the combustion control time. Control is delayed. In order to prevent this, in this embodiment, the water amount proportional adjustment valve 33 is moved in advance before starting combustion.

Therefore, the adjustment time of the water stone proportional adjustment valve 33 from the initial setting to the opening corresponding to the set temperature during FF control (to be described later) is shortened, so the FF control is immediately activated.
The HB can be quickly set to the set temperature.

When the opening degree is set to allow the maximum amount of water to enter with respect to the combustion capacity, the geared motor is turned off (S4).

When the opening degree is not set to allow the maximum amount of water, the geared motor is turned on (S5).

Normally, the driving time of the water level proportional adjustment valve 33 is about a few seconds even if the maximum displacement occurs, but if the water level proportional adjustment valve 33 is frozen or mixed with foreign matter, the water level proportional adjustment valve 33 will be locked, so the geared motor drive Even though the circuit 74 is energized, the water stone proportional adjustment valve 33 may not be displaced, and as a result, the energization time becomes longer and there is a risk of burnout due to heating of the motor or geared motor drive circuit 74. In this embodiment, in order to prevent equipment failure even in such a case, the geared motor is turned off after the energization time by the geared motor drive circuit 74 is ti (for example, 5 to 30) seconds (S6). .

Next, it is determined whether or not the operating switch 56,56a of the main controller 54 or sub-controller 54a is turned on (S7), and step 87 is repeated until it is turned on. When turned on, the water temperature setting switch 57.57
Determine whether or not the hot water temperature is set by a (S8
).

Further, if the hot water temperature is not set even after a predetermined period of time (t2 seconds) has elapsed (S9), the set temperature is set to the reference temperature of 40°C (810). Next, when the user opens the hot water tap (5
11), detecting the amount of water entering by the water amount sensor 36 (S1
2).

Here, when accepting the inflowing water amount change signal, a minute change that is not detected by the inflowing water amount detection circuit 76 is not accepted, and the amount of change in the inflowing water amount is greater than or equal to a predetermined value compared to the current amount of inflowing water (steady flow). Accept when.

Hydrosphere detection circuit 76 that reads the signal from the water amount sensor 36
If the signal exceeds a predetermined voltage, it is detected as a water flow signal, but reading errors will occur in the water flow detection circuit 76 due to undulations in the water flow, and chattering will occur if the set voltage is kept constant. In the embodiment, chattering is prevented by providing a hysteresis characteristic, and when the water stone is 251/min or more, it is detected as a water flow signal; 2.
Oj! When there is a minute change of less than /min, it is not detected as a water flow signal.

Normally, the water inflow data is updated every sampling time, but taking into account the response delay of the water inflow sensor 36, the water inflow may also change if the cumulative value within a certain time exceeds a predetermined value. accepted as

Therefore, it is possible to detect not only an instantaneous change in the amount of water inflow, but also a change in the amount of water inflow within a certain period of time, and it is possible to adjust the gas m in response to a wide range of changes in the amount of water inflow.゛After detecting the amount of water entering, after a predetermined time (t3 seconds) has elapsed (S
13) The incoming water temperature is detected by the incoming water temperature thermistor 35 (314). Then, it is determined whether the incoming water temperature is 55°C or higher (815), and when the temperature is 55°C or higher, the user closes the hot water tap (316), and the operation switches 56 and 56 of the main controller 54 and sub-controller 54a are activated.
Turn OFF a (517). When the temperature is lower than 55° C., it is determined whether the inlet water temperature is below the set temperature (S18), and when the temperature is higher than the set temperature, the operation of 812 and below is repeated, and when the temperature is below the set temperature, the fan 12 is turned on (S19).

The number of rotations of the fan 12 is detected by the Hall IC.
), and determines whether the rotation speed is equal to or higher than a predetermined rotation speed (52
1). When the rotation speed is lower than the predetermined rotation speed, the rotation speed corresponding to the combustion capacity cannot be obtained. ~26), the user closes the hot water tap (S27), and then turns off the operation switches 56, 56a of the main controller 54 and subcontroller 54a (828).

When the rotational speed is equal to or higher than a predetermined rotational speed, t4 (for example, 0.
Perform pre-purge for 5 to 10 seconds (S29), turn on the sparker 14, the main solenoid valve 21, the main solenoid valve 22, and the switching valve 24 (830 to 33), and supply a slow ignition current to the governor proportional valve 23. (S34).

As shown in FIG. 10, the amount of current applied to the governor proportional valve 23 is controlled based on the rotational speed of the fan 12, that is, the air volume, and the gas type Kp, except at the time of ignition. In this embodiment, in particular, the amount of gas for slow ignition during ignition is made to be a constant ratio to the maximum value of the current to the governor proportional valve 23 adjusted by a semi-fixed volume of the proportional valve control circuit 73. This makes it possible to supply an appropriate amount of slow ignition gas at the time of ignition.

Further, after tS (for example, 5 to 20) seconds have elapsed after turning on the sparker 14 (S35), the sparker 14 is turned off (S36). Then, the combustion flame is detected by the flame rod 15, and it is determined whether or not a current of more than ■△ is inputted by the flame rod 15 (837).
. If a current of IA or higher is not input, the operation of 822 or lower will be repeated as an ignition error.

When a current higher than IA is input, a slow ignition timer for tS (for example, 0.1 to 10) seconds is performed (838);
The outlet Wm is detected by the outlet hot water temperature thermistor 38 (S39
).

Next, the combustion capacity control shown in the operation flowcharts of FIGS. 6 to 8 is performed (S40), and the following safety function control is performed.

Determine whether the rotation speed of the fan 12 is equal to or higher than a predetermined rotation speed (
841). When the rotation speed is lower than a predetermined rotation speed, an operation of 322 or less is performed, and when the rotation speed is higher than a predetermined rotation speed, it is determined whether or not a current of IA or more is being inputted by the frame rod 15 (S42). When a current higher than IA is input, continuous combustion may continue for t7 (for example, 40 to 120) minutes (843), or the temperature of the hot water reaching the boiling point may exceed the boiling temperature (843).
844), and if this continues for ta (for example, 1 to 10) seconds (S45), the operations from 822 onwards are repeated. If the continuous combustion is within t7 minutes and the hot water temperature does not reach the boiling temperature, after inputting the set temperature again (846),
Repeat the operations below. S46 is for dealing with the case where the user changes the set temperature.

When a current equal to or higher than IA is not input, a misfire such as blowout is detected, and it is determined whether or not this is the first misfire during combustion (547), and when the misfire is the second, the operations from 822 onwards are repeated. When a misfire occurs for the first time, the original solenoid valve 21, main solenoid valve 22, and switching valve 24 are set to 0FFL.

(848-50), then repeat the operations from 319 onwards.

The combustion capacity control will be explained based on the operation flowcharts shown in FIGS. 6 to 8.

First, the required capacity for combustion capacity control is calculated based on the following formula (5ioo), (8101).

Formula 1...Calculated value Q= (Tset -THin)
xw formula 2...calculated value q= (THout -THin
) 310 to determine whether t9 seconds have elapsed after the initial setting.
3) After t9 seconds have elapsed, it is determined whether Q≧qx (S104).

When Q≧qx is not, determine whether Q<q or not.5105
), when Q<o does not exist, in order to bring the hot water temperature closer to the set temperature, combustion is performed with a slow heating capacity of QX 1.0.
The fan 12, governor proportional valve 23, switching valve 24, and water volume proportional adjustment valve 33 are controlled (8106).

When Q<q, the hot water temperature is higher than the set temperature, so in order to bring the hot water temperature closer to the set temperature, the fan 12 and the governor are set so that combustion is performed with the minimum combustion capacity (residual heat purge capacity). The proportional valve 23, the switching valve 24, and the water volume proportional adjustment valve 33 are controlled (3107). Calculate τ+, = a/W [seconds] (8108), τ1 second has elapsed (8109)
After that, the fan 12, the governor proportional valve 23, the switching valve 24, and the water volume proportional adjustment valve 33 are controlled so as to burn with a combustion capacity that brings (Q+α)/Q close to QX 1.0 (5110),
Then, PI sub-control is performed.

Here, if τ1 second has not elapsed, the set temperature Bs
The deviation 1dtl between et> and output yJ temperature (THout) is ±
Determine whether the temperature is within y℃ (3111) and calculate the deviation 1dt1
is within ±y℃, perform 5110 and the deviation 1dtl is ±
If the temperature is not within y°C, perform step 5109 again.

Errors due to variations in the water heater or cases where the gas pressure is lower than the standard Q@ may occur, so when t9 seconds have elapsed (8103) after moving to the initial setting position, the temperature detected by the outlet hot water temperature thermistor 38 is The set temperature is not achieved Q≧q
When x, the set temperature (Tset> and output 4fjj, (
It is determined whether the deviation 1d from THout) is within +y'C (S112), and when the deviation 1dtl is within ±y°C, perform 8106, and when the deviation 1d[1 is not within ±y°C , ((Q+α)/Q), the fan 12, the governor proportional valve 23, the switching valve 24, and the water volume proportional adjustment valve 33 are controlled so that the combustion occurs with a rapid heating capacity of ((Q+α)/Q) (S113).

At this time, for example, the water volume proportional adjustment valve 33 is set in advance to CplJ.
Read the data input to 70 and immediately calculate the deviation 1d between the set temperature (Tset) and output 13 [(THout).
The opening degree is narrowed down according to t1.

However, the combustion capacity calculation value is updated due to the change in the amount of water, and if the combustion control is activated at this time, the change in gas flow and the change in the amount of water entering will interfere, and the outlet hot water temperature will be affected, so it is necessary to maintain the maximum capacity combustion. When changing the opening degree of the water volume proportional adjustment valve 33, the gas volume is not adjusted by controlling the fan 12 and the governor proportional valve 23.

Here, it is determined whether or not the switching valve 24 is turned on (3114). When the switching valve 24 is turned on, that is, when the first burner 11a and the second burner 11b are operating at full capacity by simultaneous combustion, It is determined whether the output is below the maximum range of the half-open capacity control area I (capacity 172 of the full-open capacity control area Il area ■) or not (5115), and when it is not below the maximum area, the governor proportional valve 23 is activated with the output within the overlap control area ■. to gas proportional control (
S 116).

When the switching valve 24 is not turned on, that is, during half-open capacity operation with combustion of only the first burner 11a, check whether the full-open capacity side a range ■ is equal to or higher than the minimum range (capacity 174 of the full-open capacity control range ■). 5117), and when it is not greater than the minimum range, perform 5116.

Therefore, the judgment level of the rapid heating capacity (Q+α) is equal to or lower than the maximum area of the half-open capacity sub-area ■=maximum area of the half-open capacity control area ÷ ((Q+α)/Q), and the full-open capacity control la
Limited to overlapping mt area ■ that is greater than or equal to the minimum area of area ■ (
Fixed value). This turns the switching valve 24 ON and OFF.
It is possible to prevent chattering between fully open and half open the gas burner 11 that occurs due to this, and it is possible to both expand the temperature range and speed up the control of the rapid heating ability.

Next, calculate τ2=b−cw [seconds]3118), τ
After 7 seconds have elapsed (S119), control the fan 12, governor proportional valve 23, switching valve 24, and water volume proportional adjustment valve 33 so that combustion occurs with residual heat purge capacity of (Q-β)/Q (5120), Then, PI sub-control is performed.

Here, if τ2 seconds have not elapsed, it is determined whether the deviation 1d between the set 'fA degree (TSet) and the output am (THout) is within ±y°C (3121), and the deviation 1d
When t1 is within y”c, perform 8120, and the deviation is 1 d
When t l is not within ±y℃, output &i for a predetermined time Δt
It is determined whether there is a change in the outlet hot water temperature that is less than or equal to the temperature difference Δy (S122). When there is a change in the outlet temperature less than or equal to Δy/Δ, step 5120 is performed, and when there is no change in outlet hot water temperature less than or equal to Δy/Δ, the operation for $119 or less is repeated.

The PI sub-control controls the set temperature (rset) and output temperature (T
) lout) is greater than or equal to +y℃.
S123), when the deviation is +y℃ or more, control the fan 12, governor proportional valve 23, switching valve 24, and water volume proportional adjustment valve 33 so that combustion occurs with residual heat purge capacity of (Q-β)/Q5124) , tlo seconds have passed (S125), the above-mentioned safety control is performed. Further, when t10 seconds have not elapsed, the operations from 8123 onwards are repeated.

When the deviation is not more than +y℃, calculate the integral time from the composite function of the temperature deviation function and the large water flow function (S127)
.

Temperature deviation: e General constant temperature - Output water temperature "F (e) - (K + - e) Xkl, constant water input 11w is a known number detected by the water flow sensor, °,
G (W) = (K2-e) xk =, °, integration time: T =: + X [F (e) + G (w)) = PI
Depending on the output time of proportional control, the greater the deviation between the set temperature and the hot water temperature, the shorter the integral time [seconds], or the greater the amount of water input, the shorter the integral time.
The output time to the governor proportional valve 23 or the water volume proportional adjustment valve 33 becomes shorter.

After that, after 1 hour (8128), the temperature deviation e
Determine whether or not ≦1 (3129), when e≦1, perform the above-mentioned safety control, and when e≦1, input the gas type Kp of the fuel gas (3130), adjust the proportion according to the gas type Kp. In order to switch to the control constant, perform the following PI control output update, and then update the PI! ! Governor proportional valve 2 with i+1gfJ output
3 or after outputting the proportional control constant to the water mother proportional adjustment valve 33 as a temperature deviation function (3131), safety control is performed.

PI proportional system control (l output PN = PN-1 + exKp proportional output change date: Δ■5 = exKp PN-1 = Q + α: current PII example control output, ', p
r Proportional control output PN = PM-1 + ΔVS However, when the amount of water entering is less than the predetermined flow rate, the maximum value of the output is brought closer to (Q + α)/Q QX 1.0 to improve stability in minute flow ω. .

Therefore, by switching to proportional control constants according to the load such as gas type Kp, gas amount, and water inflow amount, the gas amount can be increased or decreased (not a fixed value but a variable), allowing for wide-range and free PI sub-control. It can be carried out. Furthermore, PI sub-control that is compatible with the characteristics of the governor proportional valve 23 (which differs depending on the type of gas) can be performed.

Roughly speaking, based on the integral time T and the PII example control output, the outlet hot water temperature can be brought closer to the set temperature quickly.

Further, a predetermined amount of gas may not be obtained due to the gas type Kp of the fuel gas or the pressure loss of the gas supply pipe 20.

In this case, the amount of current applied to the governor proportional valve 23 is determined by replacing the minimum current during full-open capacity operation with A1 to A2 and the maximum current during half-open capacity operation with 81 to 82, as shown in the graph of Fig. 10. controlled so that a predetermined amount of gas is obtained.

Here, by the PI sub-control, if the following conditions are reached, the dual gas burner 11 is switched based on the operation flowchart shown in FIG. 8 to achieve a safe combustion condition and smooth control. .

When the P H-1 proportional control is output, the switching valve 24 is turned on.
3200), when the switching valve 24 is not turned on, that is, during half-open capacity operation with only the first burner 11a ignited, the governor proportional valve 23 is switched on by gas proportional control in the half-open capacity control area (3). control the current to
Automatically adjust the gas level (8201).

At this time, it is determined whether or not the gas proportional control is near the maximum range of the half-open capacity-specific A area work (5202), and when it reaches near the maximum range, a full-open switching signal is output (S203).

The full open switching signal uses a limit on the supply voltage to the fan 12 or the current value to the governor proportional valve 23.

The gas proportional control remains near the maximum range of the half-open capacity control area for a certain period of time t11 (for example, 5 to 30 seconds) after the full-open switching signal is output (S204), (S205)
), a slow ignition current should be supplied to the governor proportional valve 23.
206), turn on the switching valve 24 (S 207), and
By simultaneous combustion of the burner 11a and the second burner 11b, the switch is made to the full open capacity control area ■.
The gas proportional control controls the current to the governor proportional valve 23 and automatically adjusts the gas amount.

When the switching valve 24 is ON, that is, the first burner 1
During full-open capacity operation with simultaneous combustion of burner 1a and second burner 11b, the current to governor proportional valve 23 is controlled by gas proportional control in full-open capacity control area (2), and the gas amount is automatically adjusted (8208).

At this time, it is determined whether the gas proportional control is near the minimum range of the full-open capacity control range (8209), and when it reaches near the minimum range, a half-open switching signal is output (8210).

The half-open switching signal uses a limit on the supply voltage to the fan 12 or the current value to the governor proportional valve 23.

A certain period of time t12 (for example, 5
~30 seconds) Gas proportional control controls full opening capacity! It remains near the minimum region of lI region ■ (S211), (S212
), the switching valve 24 is set to 0FFL (3213), and the current to the governor proportional valve 23 is controlled by gas proportional control of the half-open capacity control area by combustion of only the first burner 11a,
Automatically adjusts the gas amount.

At this time, the air volume of the fan 12 and the current to the governor proportional valve 23 each correspond to the optimum value, and are constant regardless of whether the gas burner 11 is fully open or half open.
Since the inertial force is large and there is a response delay, fan 12's J!
The current to Ill and governor proportional valve 23 remains unchanged.

Therefore, a complete combustion state and smooth switching control from half-open to full-open or from full-open to half-open can be performed.

Further, each of the first burner 11a and the second burner 1
1b has a capacity limit, and depending on which burner can cover the limit value, the control range can be expanded by switching the switching valve 24, but the method of detecting the switching signal with an instantaneous value is In water heaters such as the water heater 1, which have a large heat capacity or have a delayed response, a chattering phenomenon occurs, causing control failures. However, in the case where the burner is switched to a predetermined burner when the burner remains in the switching area for a certain period of time as in this embodiment, chattering caused by turning the switching valve 24 ON and OFF can be prevented.

In this embodiment, gaseous fuel such as fuel gas is used as the fuel, but liquid fuel such as petroleum may also be used as the fuel.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing a gas combustion type water heater employing an embodiment of the present invention, Fig. 2 is a block diagram showing a gas combustion type water heater employing an embodiment of the present invention, and Figs. Fig. 8 is an operation flowchart of a gas combustion water heater employing an embodiment of the present invention, and Fig. 9 shows the opening degree of the governor proportional valve for a gas combustion water heater employing an embodiment of the present invention. FIG. 10 is a graph showing the relationship between the fuel gas supply port and the gas amount and the current flowing to the governor proportional valve in a gas combustion type water heater employing an embodiment of the present invention. be. In the diagram 1... Gas combustion water heater 11... Gas burner -
3... Heat exchanger 20... Gas supply pipe (fuel supply path) 23... Governor type gas proportional valve (fuel supply amount control means) 24... Solenoid valve for switching 35... - Inlet water temperature thermistor (Incoming water temperature detection means) 38... Output hot water temperature thermistor (Output water temperature detection means) 50... Control device 60... Control circuit 70... Microcomputer (CPU) 7
3...Proportional valve control circuit

Claims (1)

[Scope of Claims] A fuel supply amount control means for adjusting the amount of fuel supplied, a first burner connected to a fuel supply path via the fuel supply amount control means, and a switch for controlling the fuel supply amount. a burner consisting of a second burner connected via a solenoid valve; a heat exchanger provided above the burner to heat the water passing therethrough; and a heat exchanger provided downstream of the heat exchanger to heat the water passing through the burner. Outlet hot water temperature detection means for detecting the outlet temperature of the water flowing out from the heat exchanger; temperature setting means for setting the outlet temperature of the water flowing out from the heat exchanger to a desired set temperature; and a deviation between the set temperature and the outlet hot water temperature. Based on the above, during half-open capacity operation with combustion of only the first burner, half-open capacity control range controlled by proportional control, and full-open capacity operation with simultaneous combustion of the first burner and second burner. , a full-open capacity control range controlled by proportional control and an overlapping control range of the maximum range of the half-open capacity control range and the minimum range of the full-open capacity control range are selected, and the switching solenoid valve is controlled according to these control ranges. In a water heater equipped with a control circuit that performs feedback control to open or close the valve and automatically adjust the amount of fuel supplied, the feedback control causes the proportional control to reach near the maximum range of the half-open capacity control range. the switching signal for a certain period of time is reached, and a switching signal to the full-open capacity control area is output, or when the minimum range of the full-open capacity control area is reached and a switching signal to the half-open capacity control area is output. A water heater characterized in that the switching solenoid valve is opened or closed only when an output is being output.