JP3109776B2 - Water heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water supply apparatus in which a heating amount is adjusted by intermittently burning a burner.

[0002]

2. Description of the Related Art Japanese Patent Publication No. Hei 3-4811 and Japanese Patent Publication No. Hei 3-28663 disclose the next intermittent operation based on the average value of the required heat quantity in the immediately preceding intermittent combustion period (composed of a combustion period and a fire extinguishing period). Length of burning period and burning time,
A technique for obtaining hot water at a set temperature by determining a fire extinguishing time is described.

[0003]

However, the following problem arises in the method of determining the length of the next intermittent combustion period, the combustion time within that period, and the fire extinguishing time in units of the intermittent combustion period. First, the required amount of heat is relatively small, for example, combustion time 1
When a relatively long intermittent combustion period of 7 seconds and a fire extinguishing time of 7 seconds is set, a new combustion time and a new fire extinguishing time are set even if the set temperature of the temperature setting device is adjusted to, for example, a high temperature side during this period. Since it is from the next period, a maximum time delay of 8 seconds is required before the amount of heat supplied from the combustion part such as a burner to the heat exchanger is increased and the average value of the hot water temperature starts to rise. Occurs.

When the required heat quantity is relatively large, for example, when an intermittent combustion period is set such as a combustion time of 4 seconds and a fire extinguishing time of 1 second, even if the set temperature is adjusted to be low in the middle of the period, the temperature of the tap water is not changed. Up to 5 until the mean of
A second delay occurs.

[0005] Not only when the set temperature is changed, but also when the amount of hot water is changed by adjusting the opening degree of the hot water tap, the combustion time and the fire extinguishing time corresponding to the new required heat amount will be from the next intermittent combustion period. Therefore, the average value of the tapping temperature may temporarily deviate from the desired temperature.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and its object is to reduce fluctuations in tapping temperature by correcting the preset combustion time and fire extinguishing time when the required heat quantity changes. To provide a hot water supply device.

[0007]

In order to solve the above-mentioned problems, a hot water supply apparatus according to the present invention provides an intermittent combustion period when a required amount of heat fluctuates during an intermittent combustion period including a combustion time and a fire extinguishing time. Intermittent combustion control means for changing the combustion time or the fire extinguishing time or both without waiting for the completion of the control.

[0008]

When the required amount of heat fluctuates, the intermittent combustion control means corrects the combustion and fire extinguishing times. Accordingly, the response time to the change in the required heat amount is shortened, and it is possible to prevent the tapping temperature from greatly deviating from the set temperature.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an overall configuration diagram of a hot water supply apparatus according to the present invention. The hot water supply apparatus 1 is a feedforward control type intermittent combustion hot water supply apparatus. In the hot water supply apparatus 1, gas supplied through a gas pipe 2 is burned in a combustion unit 3 such as a burner, and water supplied from a water supply pipe 4 is heated by a heat exchanger 5, and the hot water supply pipe 6 Take water from the side. The gas pipe 2 is provided with an electromagnetic on-off valve 7 and a governor 8.
The water supply line 4 is provided with a water temperature sensor 9 and a flow rate sensor 10.

The water temperature sensor 9 is configured to obtain a voltage signal 9a corresponding to the water temperature by using a heat sensitive element such as a thermistor. The water temperature detector 11 includes an A / D converter and the like,
Is output. The flow sensor 10 generates a pulse signal 10a for each predetermined amount of water. The flow detector 12 outputs a digital signal related to the flow Q according to the cycle of the pulse signal 10a. Temperature setting unit 1
3 is a set temperature TS set by a temperature setter (not shown).
And outputs a digital signal corresponding to.

The required calorie calculating unit 14 calculates the required calorie FF by multiplying the temperature difference (TS-TC) between the set temperature TS and the water temperature TC by the flow rate Q, and outputs the required calorie. The calculation of the required heat quantity FF of the feedforward control type is performed at predetermined time intervals (for example, every 100 milliseconds).

The intermittent combustion control means 15 determines a combustion time and a fire extinguishing time based on the required heat quantity FF and issues an open / close signal 15a. The heat quantity latch means 16 and the latch control means 1
7, a calorie fluctuation detecting means 18, an intermittent combustion table 19, a burning time specifying means 20, a fire extinguishing time setting means 21, an opening / closing signal generating means 22, and a burning / extinguishing time correcting means 23.

The latch control means 17 detects the rise of the open / close signal 15a and outputs a heat quantity latch command 17a.
The required amount of heat FF is latched by the amount of heat latch means 16. After outputting the heat quantity latch command 17a, the time latch command 17a is considered in consideration of the output delay time of the intermittent combustion table 19.
b, and writes the combustion time data 19a and the fire extinguishing time data 19b output from the intermittent combustion table 19 to the combustion time specifying means 20 and the fire extinguishing time specifying means 21, respectively.

The intermittent combustion table 19 is composed of a ROM or the like in which data of a combustion time and a fire extinguishing time set in advance for each required heat amount FF is stored, and a combustion time corresponding to the heat amount 16a latched by the heat amount latching means 16. The data 19a and the fire extinguishing time data 19b are output.

The open / close signal generating means 22 outputs an H-level open / close signal 15a while counting the elapsed time based on a reference clock signal or the like until the time supplied from the combustion time designating means 20 is reached, and the combustion time elapses. After that, the L-level open / close signal 15a is output until the fire extinguishing time supplied from the fire extinguishing time designating means 21 elapses. Further, when the open / close signal generating means 22 outputs the H-level open / close signal 15a, that is, the combustion command, the elapsed time data from the time when the output of the signal 15a is started, that is, the combustion elapsed time data 22a is changed to L level. In the state where the level opening / closing signal, that is, the fire extinguishing command 15a is output,
The elapsed time data from the start of the output of a, that is, the fire extinguishing elapsed time data 22b is supplied to the combustion / extinguishing time correcting means 23.

The open / close valve driving means 24 drives the open / close valve 7 to the open state when the open / close signal 15a is at the H level to bring the combustion part 3 into the combustion state, and when the open / close signal 15a is at the L level, the open / close valve 7 Is driven to a closed state to put the combustion part 3 in a fire extinguishing state.

The calorie fluctuation detecting means 18 calculates the latched calorie 16a, that is, the calorie required for setting the combustion / extinguishing time of the current intermittent combustion period and the calorie FF sequentially supplied at predetermined time intervals. If the difference is larger than a preset value, a latch command 18a is output to latch the new required heat quantity FF to the heat quantity latch means 16 and the correction request 18b is sent to the combustion / extinguishing time correction means 23. Supply. Since the new required heat amount FF is latched, the intermittent combustion table 19 outputs combustion time data 19a and fire extinguishing time data 19b corresponding to the new required heat amount FF.

Upon receiving the correction request 18b, the combustion / extinguishing time correcting means grasps the progress of the intermittent combustion period based on the combustion elapsed time data 22a and the fire extinguishing elapsed time data 22b. If the correction request 18b occurs during the combustion period, the elapsed time 22a from the start of combustion and the new combustion time 19a are compared. When the new combustion time 19a is longer than the elapsed time 22a, the new combustion time data and the fire extinguishing time data are supplied to the combustion time specifying means 20 and the fire extinguishing time specifying means 21 via the signal paths 23a and 23b, and each time is supplied. Update the data. For example, if the initial settings are a combustion time of 1 second and a fire extinguishing time of 4 seconds, and a correction request to the combustion time of 2 seconds and the fire extinguishing time of 2 seconds is issued before the combustion time of 1 second elapses, a new combustion The time and the fire extinguishing time are supplied as they are to the respective designating means 20 and 21, and intermittent combustion is performed with a burning time of 2 seconds and a fire extinguishing time of 2 seconds.

If the new combustion time is shorter than the elapsed time of the combustion state, the combustion / extinguishing time correction means 23 supplies the elapsed time data 22a of the combustion state to the combustion time designating means 20 via the signal path 23, The output 15a of the opening / closing signal generating means 22 is forcibly shifted to the L level (fire extinguishing command).
At the same time, the combustion / extinguishing time correcting means 23 satisfies the ratio of the new burning time supplied from the intermittent combustion table 19 to the new extinguishing time with respect to the elapsed time of the combustion state, that is, the actual burning time. Then, the fire extinguishing time is calculated, the calculated fire extinguishing time is supplied to the fire extinguishing time designating means 21 via the signal path 23b, and the fire extinguishing time data is updated.
For example, 3 seconds after the start of combustion, 2 seconds of combustion time, and 1 hour of fire extinguishing time
When the change to the second is requested, since the combustion has already been performed for 3 seconds, the fire extinguishing time 1.5 seconds, which is a ratio of 2: 1 to the 3 seconds, is calculated, and the time 1.5 seconds is calculated. Is the fire extinguishing time of this intermittent cycle.

When a correction request is issued during the fire extinguishing period, the extinguishing time is calculated with respect to the initial burning time so as to satisfy the ratio of the new burning time to the extinguishing time. For example, if the initial burning time is set to 4 seconds and the initial fire extinguishing time is set to 3 seconds, and a request for changing the burning time to 2 seconds and the extinguishing time to 1 second is made during the fire extinguishing period, the burning period has already ended. Therefore, it is assumed that the combustion time of this intermittent cycle is 4 seconds and the fire extinguishing time is 2 seconds so as to satisfy the ratio of the burning time and the fire extinguishing time of the change request. Then, the calculated fire extinguishing time is supplied to the fire extinguishing time setting means 21 via the signal path 23b to be updated. As a result, if the actual fire extinguishing elapsed time 22b exceeds the updated fire extinguishing time, the open / close signal generating means 22 changes its output from the L-level fire extinguishing command to the H-level combustion command. Also,
If the updated fire extinguishing time is longer than the actual fire extinguishing elapsed time 22b, an L-level fire extinguishing command is output until the updated fire extinguishing time is reached.

If a correction request is issued during the fire extinguishing period, the fire extinguishing time 19b output from the intermittent combustion table 19 is not adjusted based on the above-described ratio between the burning time and the fire extinguishing time. Is compared with the elapsed time from the start of fire extinguishing. If the extinguishing time 19b is longer than the elapsed time, the fire extinguishing state is maintained until the extinguishing time is reached. May be shifted to the combustion state.

As described above, the intermittent combustion control means 15 can control the required amount of heat even during the intermittent combustion period.
Since the combustion time and the fire extinguishing time during that period are corrected, hot water temperature control with excellent responsiveness can be performed. In addition, since the combustion time and the fire extinguishing time are corrected when the required amount of heat fluctuates by a predetermined value or more, the correction operation is not frequently performed by a slight change in the water temperature or the flow rate.

FIG. 2 is a block diagram of another hot water supply apparatus according to the present invention. The hot water supply device 31 adjusts the amount of heat using both feedforward control and feedback control. The description will focus on differences from the hot water supply apparatus shown in FIG. A hot water temperature sensor 32 is provided in the hot water supply line 6, and its output is converted into a digital signal TH corresponding to the hot water temperature by an A / D converter in the hot water temperature detection unit 33.

The average hot water temperature calculating section 34 takes in the hot water temperature TH at predetermined time intervals, adds the hot water temperature TH, and outputs the average hot water temperature THA divided by the added data number. The feedback calorie calculation unit 35 calculates and outputs the feedback calorie FB by multiplying the difference between the set temperature TS and the average tapping temperature THA by the flow rate Q.

The calorie correction unit 36 outputs a required calorie F obtained by adding the required calorie FF of the feedforward system and the feedback calorie FB. The intermittent combustion control means 15 determines the combustion time and the extinction time of the intermittent combustion with the required heat amount F as an input, and causes the intermittent combustion to be performed.

FIG. 3 is a block diagram showing a specific example of the average hot water temperature calculating unit. This average hot water temperature calculation unit 34
A rising detection unit 41 that detects a rising of the opening / closing signal 15a and generates a reset pulse signal 41a; an integration timing output unit 42 that supplies an integration command 42a at predetermined time intervals (for example, 500 milliseconds); Each time the hot water temperature data TH is received and integrated, a tapping temperature integrating section 43 that integrates the hot water temperature data TH, a counter 44 that advances based on an integration command 42a, and an average of the hot water temperature integrated data 43a divided by the count value 44a of the counter 44. And an average tapping temperature calculation unit 45 that outputs tapping temperature data THA.

When the reset pulse signal 41a is supplied, the tapping temperature integrating section 43 clears the integrated data 43a (to zero), and the counter 44 sets the reset pulse signal 41a.
When a is supplied, the count value 44a is cleared. Therefore, the average hot water temperature calculating section 34 can calculate the average hot water temperature THA in synchronization with the intermittent combustion cycle.

As described above, the water heater 31 shown in FIG.
Uses both feed forward control and feedback control to adjust the amount of heat, so that the temperature difference (so-called offset) between the set temperature TS and the tapping temperature TH can be reduced. Further, the intermittent combustion type hot water supply apparatus repeats combustion and fire extinguishing, so that the tapping temperature periodically changes. However, an average tapping temperature calculation unit 34 is provided to calculate the average tapping temperature THA and then to calculate the feedback heat amount FB. And so
Stable feedback control can be performed.

Furthermore, the present invention is not limited to the intermittent combustion hot water supply apparatus described in the above embodiment, but can be applied to a hot water supply apparatus that selects between proportional combustion and intermittent combustion according to the required amount of heat. Needless to say. Further, the calculation of the necessary heat amount for determining the intermittent combustion period is not limited to that described in the embodiment, and various control methods can be used.

[0030]

As described above, the hot water supply apparatus according to the present invention is configured to correct the combustion time and the fire extinguishing time with respect to the current intermittent combustion period when the required amount of heat fluctuates. Excellent responsiveness to changes in required heat.
Therefore, it is possible to prevent the tapping temperature from greatly deviating from the set temperature.

[Brief description of the drawings]

FIG. 1 is a block diagram of a hot water supply apparatus according to the present invention.

FIG. 2 is a block diagram of another hot water supply apparatus according to the present invention.

FIG. 3 is a block diagram showing a specific example of an average hot water temperature calculating unit.

[Explanation of symbols]

 1, 31 Hot water supply device 3 Burning section 5 Heat exchanger 7 Open / close valve 9 Water temperature sensor 10 Flow rate sensor 14 Required heat quantity calculation means 15 Intermittent combustion control means 19 Intermittent combustion table 23 Combustion / extinguishing time correction means F, FF Required heat quantity FB Feedback heat quantity Q flow rate TC water temperature TS set temperature TH tapping temperature

Continuation of the front page (72) Inventor Tetsuro Takada 43-1 Uozakihama-cho, Higashinada-ku, Kobe-shi, Hyogo Prefecture Inside of Nippon Yupro Co., Ltd. Inside the company (72) Inventor Kiyotaka Nakano 431-1 Uozakihama-cho, Higashi-Nada-ku, Kobe-city, Hyogo Prefecture Inside (72) Inventor Hikaru Hiragun 43-1 Uozakihama-cho, Higashi-Nada-ku, Kobe-shi, Hyogo Inside Nippon Yupro Corporation (56) References JP-A-61-3946 (JP, A) JP-A-61-116236 (JP, A) JP-A-62-33217 (JP, A) JP-A-63-7471 (JP, U) 63-43035 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F24H 1/10 302

Claims (1)

(57) [Claims] 1. A heat amount required to maintain the temperature of hot water in a hot water supply pipe at a set temperature is calculated, and a combustion time and a fire extinguishing time are determined based on the required heat amount. In the hot water supply device that intermittently burns the combustion unit that heats the heat exchanger, if the required heat amount fluctuates during the intermittent combustion period including the combustion time and the fire extinguishing time, the intermittent combustion period ends. A hot water supply device comprising intermittent combustion control means for changing the combustion time and / or the fire extinguishing time without waiting.