JPH04165209A - Hot water supplying machine - Google Patents

Abstract

PURPOSE:To simplify and rationalize the manufacturing processes in great strides by the constitution that a controller that is incorporated in a hot water supplying machine judges by itself the kind of the fuel gas that is supplied to it and carries out subsequent fuel control based on the data on the kind of the fuel gas that is judged. CONSTITUTION:A certain time is beforehand specified in which the data on the temperature of the delivered hot water is likely to stabilize and this time is measured by means of a microcomputer 20, and at the time when the measurement is finished, the data on flow rate and temperature of the supply water are inputted to the microcomputer 20 and a calculation is carried out in it. The value of an acturally useful output quantity of heat that is obtained as a result varies according to the kind of the gas that is actually given to a hot water supply machine or a burner 12, and it falls within a range for each kind of gas. On the other hand, to the controller a range of value that is supposed at this time is given for each kind of gas. Now, in the microcomputer 20 calculated values are compared with the data on the value range for each kind of gas that is stored beforehand, and the kind of fuel gas be given.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for automatically discriminating the type of gas currently being supplied to a water heater that is designed to be adaptable to multiple types of fuel gas. The present invention relates to improvements in determining optimal combustion control for each type of gas, even if the control device including the microcomputer has the same hardware configuration.

[Conventional technology] Although it is a conventional example, recent water heaters have begun to use microcomputers to control combustion.
It allows for quite advanced control. In addition, some heat exchangers have a total of multiple heat exchangers, each dedicated to hot water supply, bath reheating, and the like. As will be clear from the description below, the present invention can of course be applied to such systems, but for the sake of understanding, the conventional hot water supply system, which has a relatively basic form, is shown in Figure 2. I will explain it immediately.

The illustrated water heater has a hot water outlet 15 represented by one faucet 15.
It has a hot water supply heat exchanger 11 for tapping hot water as needed. Water from the water supply pipes is passed through the hot water supply heat exchanger 11, as indicated by the arrow "water" in the figure, and this water is heated by heating the heat exchanger 11 with a burner 12. The temperature is raised.

Fuel gas is supplied to the burner 12 as combustion fuel, but the types of gas that can actually be supplied (LP, 6C, etc.) vary depending on the location where the burner 12 is installed.

However, no matter which type of gas is used, it is of course required to have the same structure, and after passing through the solenoid valve 13, the gas from the gas pipe is passed through the solenoid valve 13, based on the instructions of the microcomputer 20, abbreviated as CPU. The gas is sent to the burner 12 after being controlled to the optimum supply amount at any given time by a dedicated gas flow rate regulating solenoid valve (so-called proportional valve) 14 on the hot water supply side.
Further, the amount of air supplied to the burner 12 is similarly controlled by a fan 19 driven by an electrically controllable fan 19 based on instructions from the microcomputer 20.

On the other hand, in order to perform optimal combustion control as described above, the actual amount Q of water passing through the heat exchanger 11 that is selectively heated by the burner 12 at any given time.

is detected by the flow rate sensor 16, the temperature TC of the water before entering the heat exchanger 11 is detected by the feed water temperature sensor 17, and the hot water temperature T□ coming out of the heat exchanger 11 is detected by the hot water temperature sensor 18. Data QH, Tc, TH
is given to the microcomputer 20.

In addition, although not shown, for safety purposes, a flame is generated by a flame rod, etc. to detect whether or not the burner 12 has been ignited as specified or whether or not the burner 12 is currently burning. A detection sensor and a high limit switch that detects when the temperature of hot water from the heat exchanger 11 becomes abnormally high are also provided.Furthermore, in order to further improve controllability, a fan is installed as necessary. A sensor for detecting the air flow rate or the actual rotational speed currently output by the engine 19 and performing feedback control is also incorporated.

However, even when performing control using such a microcomputer 20, if the type of gas to be supplied differs, the software may differ depending on the type of gas supplied, even if the hardware configuration of the microcomputer 20 is the same. That is, programs, basic data, etc. must be changed and set according to the gas type.

Here, for example, the flow rate of wood or hot water passing through the heat exchanger 11 is Qo, heat exchange! ! ! When the supply water temperature, which is the temperature of the water given to the heat exchanger 11, is Tc, and the outlet temperature, which is the temperature of the hot water heated by the heat exchanger 11, is TH, the calorific value FF at that time is: FF = QH (THTC) [nical/akin
] ”・■.

However, if the gas type is different, the same heat exchanger passing flow rate Q
) the same flow rate of gas and the same flow rate of air under burner 1
2, the increased temperature T□ will vary depending on the energy of the gas. In other words, in order to control the hot water outlet temperature TH to the user's desired set temperature as much as possible, the amount of gas to be supplied (in the end, the opening degree of the proportional valve 14 or the current value applied to it) and the air The feed amount (fan rotation speed), etc. must be changed. Otherwise, there will be not only problems in temperature control, but also risks such as incomplete combustion.

However, conventionally, each gas type requires a dedicated control device in terms of hardware, or even if the hardware is almost the same, programs and various data are set specifically for each gas type. Alternatively, a control device was provided that could change settings between at least several different gas types by operating a switch.

[Problem to be solved by the invention] However, when using a control device with a dedicated hardware configuration for each gas type, it is necessary to develop one type of control device for each gas type. This required a lot of effort and wasted development resources.

On the other hand, if the programs and data for the built-in microcomputer are changed and set for each gas type, it may be possible to streamline the process a little more than the above, but on the other hand, if you only look at the appearance of the hardware, it will be difficult to tell the difference. There is,
There remained a risk of incorrect loading. There remained a risk that a control device with different gas type data could be mistakenly installed in another water heater.

On the other hand, it is configured so that it can be applied to at least some types of gas, and depending on the installation environment of the water heater that is actually installed, it can be adapted to the given gas type using a changeover switch. The method of selecting the switch position according to
Since the switch still requires manual switch operation during installation, it was not possible to completely prevent erroneous switching.

Therefore, the present invention makes it possible to use the same control device for at least some gas seconds, while eliminating the risk of manual erroneous operation when installing the control device in each water heater. The system is designed to automatically provide gas type data to the control device by actually determining the type of gas being used at the site of use.

[Means for solving the problem] In order to achieve the above objective, the ignition operation to the burner is commanded by generating a water flow exceeding a predetermined flow rate passing through the heat exchanger, and after ignition, the burner is ignited according to the hot water supply capacity of each model. In the present invention, the water heater is equipped with a control device including a microcomputer that performs optimal TJ combustion control. If gas type data specifying one type of gas is given, the configuration should be such that combustion control can be performed according to the specified type of gas. The gas type data to be provided is based on the information obtained when the heat exchanger is supplied with a constant flow rate of fuel gas and a constant flow rate of air to the burner at the beginning of the ignition operation in the water heater in which the control device is installed. It is determined based on the flow rate passing through, the temperature of water supplied to the heat exchanger, and the temperature of hot water discharged from the heat exchanger.

Further, in accordance with such a basic configuration, the present invention further provides that the above gas type data is obtained only in response to the first ignition operation after the power is first turned on to the control device, -The gas type data once determined is configured to continue to be set in the control device as long as the power continues to be turned on, and when determining the gas type data, the flow rate of the water flow passing through the heat exchanger is also fixed to a known value. We also propose a configuration.

[Function] According to the present invention, if the wound device itself including the microcomputer is given gas type data that specifies any one of at least two or more different gas types, it can be controlled accordingly. It is structured like this.

However, simply providing gas type data means that the switch operation in the conventional example described above also involves manually providing a type of gas type data to the control device, but the gas type data in the present invention is , unlike such switch operations, which are not manually operated with the possibility of erroneous operation, are automatically set upon use after being incorporated into the water heater.

In other words, when the ignition occurs in the water heater in which the control device is installed, the gas type data passes through the heat exchanger while a constant flow rate of fuel gas and a constant flow rate of air are supplied to the burner. It is determined based on the flow rate of water supplied to the heat exchanger, the temperature of water supplied to the heat exchanger, and the temperature of hot water discharged from the heat exchanger. Set.

Further, the reason why such gas type data is obtained is clear from the above-mentioned equation 0. After the user opens a hot water outlet such as a faucet, the flow rate QH becomes constant at a certain value relatively quickly, so depending on the supply water temperature Tc and the hot water outlet temperature TH at that time,
The value FF calculated by the formula 0 differs depending on the type of gas being supplied to the heat exchanger at this time.

On the other hand, under conditions where a constant gas flow rate and a constant air flow rate are given to the burner, the expected value F for each type of gas is
Each range of F can be stored in advance as data in the nonvolatile memory attached to the microcomputer, so
By referring to this, it is possible to know the type of gas that is being applied to the water heater based on the range to which the calculated value FF belongs.

In this way, if it is possible to determine the type of fuel gas currently supplied to each water heater, it is possible to provide this gas type data to the control device built into that water heater or the microcomputer built into it. Thereafter, the control device can be operated in a control mode corresponding to this gas type data.

Also, in accordance with a further sub-aspect of the invention, gas type data is determined only upon the first ignition operation after power is first applied to the controller;
If a configuration is adopted in which the settings continue to be set in the control device as long as the power continues to be turned on, it will no longer be necessary to perform the above calculation for each ignition cycle. With the exception of one ignition cycle, for the other ignition cycles, combustion control can be quickly determined to be optimal for each type of fuel gas supplied to the water heater.

Furthermore, when obtaining gas type data in the above,
If the flow rate Qs of the water flow passing through the heat exchanger is also fixed at a known value, as is clear from the above equation 0, just taking the difference between the outlet hot water temperature T and the feed water temperature Tc can be used instead of the value FF. It is possible to obtain judgment data corresponding to each gas type.

[Example] Embodiments of the present invention will be described below with reference to FIG.

However, water heaters to which the present invention can be applied or which can be improved by the present invention are most of the conventional structures as long as they have the basic configuration shown in FIG.

In other words, even if it has a separate control mechanism for reheating or a heat exchanger exclusively for reheating, the second
The present invention can be applied as long as there is a heat exchanger for hot water supply as shown in the figure.

Therefore, as an embodiment of the present invention, the apparatus configuration will be explained using the one shown in the second figure.

In a basic embodiment of the invention, the user
When a water flow passing through the heat exchanger 11 is generated by twisting the heat exchanger 11, etc., a control device including a microcomputer 20, abbreviated as CPU, controls the generation of the water flow based on the flow rate QH data from the flow rate sensor 16. Detected, original solenoid valve 13
At the beginning of each ignition cycle in which gas is to be fed from the gas pipe to the burner 12 via the is set at a certain angle and a predetermined amount of gas is supplied,
At the same time, electric power is also supplied to the fan 19 so that it rotates at a predetermined rotation speed Rs corresponding to the constant gas amount.

When the burner is ignited in this state by an ignition mechanism (not shown), a predetermined amount of heat F1 is given to the heat exchanger 11 according to the type of gas actually given. This state is shown in FIG. 1 as a time region between time t0 and determination time tl, which will be described later.

Similarly, as shown in the part after time t0 in the '$1 figure, if a constant amount of heat Ff is given to the heat exchanger 11 under constant gas flow rate and constant air flow rate, depending on each gas type. ,
At that time, depending on the temperature Tc of the water before entering the heat exchanger 11, the outlet hot water temperature TH detected by the outlet hot water temperature sensor 18 starts to rise and eventually converges to a certain stable value.

Therefore, in FIG. 1, time 1. As shown in , time t
A certain period of time during which the hot water temperature data is considered to be stable is set in advance from ll, and the time t when the measurement is completed using the microcomputer 20! Alternatively, at time 11 when the microcomputer 20 actually monitors the outlet hot water temperature TH and determines that the value has become almost stable (flow rate data QH
Normally, the data QH, TH, and Tc have already been stabilized before then), and these data QH, TH, and Tc are taken into the microcomputer 20, and the above equation 0 is calculated.

The effective output heat value FF obtained as a result varies depending on the type of gas actually supplied to the water heater or burner 12, and falls within a certain range for each type of gas.

On the other hand, in the present invention, the range of values FF expected at this time is given in advance to the control device including the microcomputer 20 for each gas type. As usual, this
This can be realized by using ROM or programmable memory.

Therefore, in the microcomputer 20, the calculated FF
By comparing the value with a pre-stored value range data group for each gas type, it is possible to determine the type of fuel gas currently being supplied to the water heater in which the water heater is installed.

In this way, by knowing the data of the gas type supplied to the water heater in which the water heater is installed, this data can be transferred to the control mode switching section of the microcomputer 20 by a program or a data group. (including software changes such as changes to
From the gas type determination time t in FIG. Combustion control similar to that in combustion control can be performed.

For example, after the judgment time t+, the respective constraints at the constant values 1s and Rs during the judgment period up to that point are released, and the flow rate Q at that time is changed. Depending on the gas type, the proportional valve current, fan rotation speed, etc. can be changed and controlled to optimal values for the gas type according to the usual method of combustion control for this type of water heater. In addition, when the flow rate changes due to the user changing the flow rate of the faucet 15, the maximum hot water supply capacity of the water heater for that gas type is effectively utilized, and the proportional valve is also adjusted accordingly. It is possible to change and control the current and fan rotation speed to their respective optimal values.

Of course, although not shown in the figure, if the user is allowed to set the desired hot water temperature (which is common these days), the hot water temperature may be maintained at the set temperature as much as possible. The control device can perform combustion control of the water heater.

However, in order to satisfy the above functions, the control device including the microcomputer used in the present invention needs to be designed and manufactured in advance so as to be compatible with at least two or more types of fuel gas. However, after being installed in a water heater, the control device can determine on its own the type of fuel gas currently being supplied to the water heater, eliminating the need for manual switching operations depending on the gas type. You don't have to worry about it, just install the control device that is common to all models in the car, and you can avoid the possibility of incorrect installation, so you can improve safety. Reliability also increases.

Furthermore, in reality, it is possible to build a control device that can adapt to not only at least two types of gas, but all the types of gas expected to be supplied to this divine water heater, and its hardware configuration is exactly the same. However, it is possible to adapt to all of these gas types by simply changing the contents of the program for running the microcomputer or the data group to be used. Considering this reality, the effectiveness of the present invention is even greater. It becomes even more extreme.

Further, in the above embodiment, the gas type was determined for each ignition cycle. However, other embodiments of the present invention may include a case where the above-mentioned determination process is performed only in the first ignition after the control device is powered on. Rather, this method is more realistic in terms of gas type determination.

When the power is turned on for the first time, it means when the water heater is first installed and the power plug is inserted into a commercial AC power outlet, and when it is restored after a power outage. By storing the gas type data obtained at the first ignition after the power is turned on in the volatile memory attached to the microcomputer, the control device can perform combustion control based on the same gas type data until the power is turned off. As a result, compared to the case where gas type data is recalculated for each ignition port, for example, control for bringing the outlet hot water temperature to the set temperature, etc., is naturally faster in terms of time.

Furthermore, if at least electrically writable, preferably rewritable, non-volatile memory is used, gas type data can be obtained according to the above only at the first ignition port when power is first turned on after the water heater is installed. By storing this in this non-volatile memory, even if the power is interrupted for a few days, for example due to a power outage or unplugging of the power plug, the contents of this memory can be read out after the power is restored and used again. Arithmetic processing becomes unnecessary.

In Fig. 1, during the gas type determination period from time t0 to 61+, the flow rate QH is controlled by a flow valve (not shown).
It is also possible to adopt a device configuration that narrows down the temperature to a constant value.If this is done, as is clear from the above equation, the calculation itself to obtain the gas type data will actually be based on the outlet hot water temperature TH and the supply water temperature T.
Only the difference calculation with C is required, which simplifies the process.

[Effect] According to the present invention, the control device built into the water heater determines the type of fuel gas being supplied to the water heater by itself, and
Subsequent combustion control is performed based on the determined gas type data, and the user does not need to intervene in the determination at all.

Therefore, unlike in the past, there is no unreasonable need to prepare a dedicated control device for each model due to the hardware configuration itself for each type of fuel gas given to the water heater; on the contrary, the hardware is common. Even so, it is necessary to install manual switches in order to allow for reuse among multiple models, which may lead to erroneous operation, or the installation of the wrong control device for each type even though the appearance of the device does not change. Such concerns are eliminated, the manufacturing process is dramatically simplified and streamlined, and the safety and reliability of the water heater are greatly improved.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram illustrating an embodiment of the present invention based on the state of each part at the time of gas type determination. FIG. 2 is an explanatory diagram of the basic components of a water heater to which the present invention can be applied. It is. In the figure, 11 is a heat exchanger, 12 is a burner, 13 is a solenoid valve, 14 is a proportional valve, 15 is a tap, 16 is a flow rate sensor, 1
F is the water supply temperature sensor, 18 is the hot water temperature sensor, 1! 1 is a fan, and 20 is a microcomputer. M2 diagram

Claims (3)

[Claims] (1) Includes a microcomputer that commands the ignition operation of the burner by generating a water flow exceeding a predetermined flow rate passing through the heat exchanger, and after the ignition, performs optimal combustion control according to the hot water supply capacity of each model. A water heater having a control device; The control device including the microcomputer is configured to select one type of gas from among a plurality of types of fuel gas that can be supplied to the burner. If the data is given, combustion control is possible according to the specified type of gas; while the gas type data to be given to the control device is At the beginning of the ignition operation in the hot water heater, a constant flow rate of fuel gas and a constant flow rate of air are given to the burner, and the flow rate passing through the heat exchanger under that condition and the water supply to the heat exchanger are calculated. A water heater characterized in that the temperature is determined based on the temperature of hot water discharged from the heat exchanger. (2) The gas type data is obtained only in conjunction with the first ignition operation after the power is first turned on to the control device, and the obtained gas type data is obtained even if the power continues to be turned on. The water heater according to claim 1, wherein the water heater continues to be set in the control device for as long as possible. The water heater according to claim 1 or 2, characterized in that: (3) when determining the gas type data, the flow rate of the water flow passing through the heat exchanger is also fixed to a known value;