JP3207415B2 - Gas water heater - Google Patents

Description

The present invention relates to a gas water heater in which a plurality of gas water heaters are connected in parallel.

[Prior Art] In general, in this type of gas water heater, a plurality of gas water heaters are sequentially operated in accordance with a hot water supply amount without being operated simultaneously. This is because each gas water heater has a minimum operating flow rate, so if all gas water heaters are operated simultaneously, the water supply amount must reach the sum of the minimum operating flow rates of all gas water heaters. None of the gas water heaters work. For this reason, there is an inconvenience that hot water cannot be supplied in an amount smaller than the total amount of the minimum operation flow rate.

By the way, as a method of switching the number of gas water heaters to be used, for example, a method described in Japanese Patent Application Laid-Open No. 64-63748 has been proposed. The gas hot water supply device described in this publication calculates a necessary heat amount from a water supply amount, a water supply temperature, and a desired hot water supply temperature, and calculates a gas amount to obtain the heat amount. Then, it is determined how many gas water heaters this required gas amount corresponds to, and the number of used gas water heaters is switched accordingly.

[Problems to be Solved by the Invention] For example, in a gas water heater in which the number of three gas water heaters to be used is switched according to a required gas amount, when each gas water heater is sequentially operated from a stopped state. Then, the hot water supply temperature changes as shown by the broken line in FIG.
That is, the hot water temperature gradually increases, but temporarily decreases when the second and third gas water heaters are operated. Then, the temperature can be raised to a set temperature (target temperature) by three gas water heaters.

Here, if the actual gas amount supplied to the burner of each gas water heater is the same as the required gas amount, the hot water supply temperature reaches the target temperature in a very short time. However, immediately after the gas hot water supply device is operated from the stopped state, the amount of gas actually supplied is significantly smaller than the required gas amount. Therefore, there is a problem that it takes a relatively long time for the hot water supply temperature to reach the stable temperature range of the target temperature.

That is, in each gas water heater of the gas water heater,
The amount of gas supplied to the burner is adjusted by the opening of the electromagnetic proportional control valve, and the opening of the electromagnetic proportional control valve is adjusted by the magnitude of the current supplied to the valve. Further, the current to the electromagnetic proportional control valve is regulated by the rotation speed of a fan for supplying air to the burner. Therefore, even if the required amount of gas is large, when the rotation speed of the fan is low, only a small amount of gas corresponding to the rotation speed of the fan is supplied to the burner.

Thus, at the beginning of the operation of the gas water heater,
Until the rotation speed of the fan reaches the rotation speed corresponding to the required gas amount, the actually supplied gas amount is smaller than the required gas amount. Therefore, even if the hot water temperature of the first gas water heater becomes high, when the second and third gas water heaters operate, the gas supply amounts to the respective gas water heaters are small, so that the hot water temperature once drops. . Therefore, there is a disadvantage that it takes a relatively long time for the hot water supply temperature to reach the stable temperature range.

The present invention has been made to solve the above-described problem, and has as its object to provide a gas water heater capable of increasing a hot water temperature to a stable temperature range in a short time.

[Means for Solving the Problems] In order to achieve the above object, the invention according to claim 1 includes n (n ≧ 2) gas water heaters connected in parallel with each other, and (n−1) ) An on-off valve installed on the water supply side of each of the gas water heaters, and a control unit for opening and closing the on-off valve, wherein the gas water heater includes a burner for heating supplied water, and a gas for the burner. An electromagnetic proportional control valve for adjusting the supply amount,
A gas hot water supply device comprising: a fan for supplying air to the burner, wherein a current to the electromagnetic proportional control valve is limited in accordance with a rotation speed of the fan. (N = 1, 2,..., N-1) based on a detection signal of the physical quantity detecting means for detecting that the physical quantity related to the rotation speed of the fan of the gas water heater has exceeded a set value; N + 1)
Valve opening means for opening the second on-off valve.

According to a second aspect of the present invention, in place of the physical quantity detecting means and the valve opening means in the first aspect of the present invention, N
Current value detecting means for detecting that a current value supplied to the electromagnetic proportional control valve of the (N = 1, 2,..., N-1) th gas water heater has exceeded a set value; (N + 1) based on the detection signal of
Valve opening means for opening the second on-off valve.

[Operation] In the invention according to the first aspect, the physical quantity detecting means is 1
Until it is detected that the physical quantity related to the rotation speed of the fan of the second gas water heater exceeds the set value, hot water is supplied only by the first gas water heater. When the physical quantity detecting means detects that the physical quantity related to the rotation speed of the fan of the first gas water heater exceeds the set value, the valve opening means opens the second opening / closing valve based on the detection signal. As a result, hot water is supplied by the first and second water heaters. Similarly, when the physical quantity detecting means detects that the physical quantity relating to the rotation speed of the fan of the second,..., (N-1) th gas water heaters exceeds the set value, the valve is opened based on the detection signal. The means opens the third,..., Nth on-off valve. As a result, 1
Hot water is supplied by the nth to nth gas water heaters.

In the invention according to claim 2, the current value detecting means is 1
Until it is detected that the current value for the electromagnetic proportional control valve of the first gas water heater exceeds the set value, hot water is supplied only by the first gas water heater. When the current value detecting means detects that the current value for the electromagnetic proportional control valve of the first gas water heater exceeds the set value, the valve opening means opens the second opening / closing valve based on the detection signal. As a result, hot water is supplied by the first and second gas water heaters. Less than,
Similarly, when the current value detecting means detects that the current values of the electromagnetic proportional control valves of the second,..., (N-1) th gas water heaters exceed respective set values, the valve is opened based on the detection signals. The means opens the third,..., Nth on-off valve. As a result, hot water is supplied by the first to n-th gas water heaters.

[Embodiment] FIGS. 1 to 3 show an embodiment of the present invention.
This will be described with reference to the drawings.

FIG. 1 shows a schematic configuration of a gas water heater according to the present invention, and the gas water heater has three gas water heaters.
It has 10,20,30. Of course, two or four or more gas water heaters may be provided.

The gas water heaters 10, 20, 30 are supplied with water supply temperature sensors 11, 21, 31, which detect the temperature of supplied water, from the water supply ports 10a, 20a, 30a toward the water supply ports 10b, 20b, 30b. Flow rate sensors 12, 22, 32, water governors 13, 23, 33, heat exchangers 14, 24, 34, and the temperature of hot water discharged from each gas water heater 10, 20, 30 Hot water temperature sensors 15, 25, and 35 are sequentially installed. In addition, the gas water heaters 10, 20, 30 have burners 16, 26, 36 for heating the supplied water via heat exchangers 14, 24, 34.
Are installed respectively. Each burner 16, 26, 36 is connected to a gas supply source (not shown) via an electromagnetic proportional control valve 17, 27, 37, and each burner 16, 26, The amount of gas supplied to 36 is regulated. Further, fans 18, 28, and 38 for supplying air to burners 16, 26, and 36 are installed in gas water heaters 10, 20, and 30, respectively. Each fan 18, 28, 38 is provided with rotation sensors 19, 29, 39 for detecting the respective rotation speeds.

The water supply ports 10a, 20a, 30a of the gas supply units 10, 20, 30 are connected to the water supply pipe 40 via branch pipes 41, 42, 43, respectively.
Electromagnetic on-off valves (on-off valves) 62, 63 are installed in the branch pipes 42, 43, respectively. The solenoid on-off valves 62 and 63 are normally-closed on-off valves, and are valve-opening signals V ₁ , V
_The valve is opened by ₂ . On the other hand, tap holes 10b, 20b, 30b of gas water heaters 10, 20, 30 are respectively connected to branch pipes 51,
It is connected to hot water supply pipe 50 via 52 and 53. Note that reference numeral 7
Reference numeral 0 denotes a faucet provided at the end of the tapping pipe 50.

Further, the gas water heater includes a control unit 80 for controlling each of the gas water heaters 10, 20, 30. The control section 80 includes a microcomputer, and receives the following various signals.

In other words, from the water temperature sensor 11, 21, 31, the feed water temperature signal Tc _1, Tc _2, Tc ₃ showing the feed water temperature, flow rate sensor 12,22,3
2, water flow signals W ₁ , W ₂ , W ₃ indicating the water supply amount, and hot water supply temperature sensors 15, 25, 35 indicate the temperature of the hot water discharged from each gas water heater 10, 20, 30. temperature signal _{Th 1, Th 2, Th 3} , from the rotation sensor 19,29,39, the rotation signal N _1, N _2, N ₃ showing respective rotational speed of the fan 18,28,38, the control unit 80 Each has been entered. Further, control unit 80 receives a target temperature signal Th from a temperature setter (not shown) for setting a desired hot water supply temperature.
₀ has been entered.

The control unit 80 controls the gas water heaters 10, 20, 30 based on the various signals according to the flowchart shown in FIG. In the flowchart shown in FIG. 2,
Matters relating to the gas water heaters 10, 20, 30 are denoted by, respectively.

After the start of the program, it is determined in step 101 whether or not the amount of water supplied to the gas water heater 10 has exceeded the minimum operation flow rate. The amount of water supplied to the gas water heater 10 is indicated by a flow signal
It is calculated based on W _1. The minimum operating flow rate is set in advance and stored in a dedicated memory of the microcomputer of the control unit 80.

If the water supply has not reached the minimum operating flow rate,
Repeat the judgment of 101.

When the amount of water supply exceeds the minimum operation flow rate, the gas water heater 10 is operated (step 102). That is, the electromagnetic proportional control valve 17
Is opened to supply gas to the burner 16 to ignite the burner 16 and rotate the fan 18.

After the operation of the gas water heater 10 is started, in step 103, the magnitude of the current to be supplied to the electromagnetic proportional control valve 17 is calculated. That is, the control unit 80, based on the feed water temperature Tc _1, the water supply amount W ₁ and the target temperature Th _0, calculates the amount of heat required to heat the water supplied to the gas water heater 10 to the target temperature, the amount of heat Calculate the amount of gas required to obtain Then, it calculates the opening degree of the solenoid proportional control valve 17 from the gas amount, and outputs a valve opening current A ₁ of a magnitude that the opening is obtained to the electromagnetic proportional control valve 17.

Further, the control unit 80 calculates the amount of air required to completely burn the gas supplied to the burner 16, and calculates the rotation speed of the fan 18 for obtaining the amount of air. Then, so the rotation speed is obtained, and outputs a driving current S ₁ to the fan 18.

However, the rotation beginning of the fan 18. needed if the rotational speed has not reached the rotation speed corresponding to the driving current S _1, the amount of gas determined by the calculation in other words to cause complete combustion air If it does not reach the rotational speed for blowing is such that the amount of gas corresponding to the rotational speed N ₁ of the fan 18 is supplied to the burner 16, the control unit 80 based on the rotational speed N ₁ solenoid regulating the current value a ₁ with respect to the proportional control valve 17. In other words, the amount of gas can be completely burned by the air amount blown by the rotating speed N ₁ is to be supplied to the burner 16, to regulate the degree of opening of the electromagnetic proportional control valve 17. This applies to the gas water heaters 20 and 30 as well.

The control unit 80, the hot water temperature Th ₂ and compared with the target temperature Th _0, the rotational speed N ₁ of the size and the fan 18 of the current value A ₁ is energized the electromagnetic proportional control valve 17 on the basis of the comparison result Is corrected.

Next, in step 104, whether or not a current value A ₁ is larger than the predetermined upper limit value is determined. The upper limit is
The current is set to a value slightly smaller than the current value for setting the opening of the electromagnetic proportional control valve 17 to 100%, for example, 90 to 95%, and is stored in the dedicated memory of the microcomputer. .

When the current value A ₁ does not exceed the upper limit value, step
At 105, it is determined whether the amount of water supplied to the gas water heater 10 is larger than the minimum operation flow rate. If the water supply amount is larger than the minimum operation flow rate, steps 103 and 104 are executed again. That is, the current value A ₁ is smaller than the upper limit value, and when the water supply amount is larger than the minimum operating flow rate is carried out hot water supply by only one of the gas water heater 10.

If it is determined in step 105 that the water supply amount is smaller than the minimum operation flow rate, the gas water heater 10 is stopped (step 106), and the process returns to step 101.

On the other hand, in step 104, if the current value A ₁ is determined to be larger than the upper limit value, the control unit 80 is the electromagnetic valve 62
(Step 107) together and outputs the valve opening signal V ₁ to open the electromagnetic valve 62 to actuate the gas water heater 20 (step 108).

Next, in step 109, it is determined whether or not the amount of water supplied to the gas water heater 20 is larger than the minimum operation flow rate.

When the water supply amount is smaller than the minimum operation flow rate, the electromagnetic on-off valve 62 is closed (Step 110), and the gas water heater 20 is stopped (Step 111). And step 1
Return to 05.

When the water supply amount to the gas water heater 20 is greater than the minimum operating flow rate, the current value A ₂ for energizing the solenoid proportional control valve 27 is calculated in step 112. This calculation is based on the feedwater temperature Tc
₂ , based on the water supply amount W ₂ , the hot water supply temperature Th _2, and the target temperature Th ₀ , in the same manner as the gas water heater 10. Of course, the driving current S ₂ at this time is also calculated. Then, the fan 28 is rotated with a rotational speed corresponding to the driving current S _2, the electromagnetic proportional control valve 27 is opened to the opening degree corresponding to the current value A _2.

Next, in step 113, it is determined whether or not the rotation speed of the fan 28 has reached a set value (rotation speed). If the number of revolutions has not been reached, the process returns to step 109.

If reached the set rotational speed, whether or not a current value A ₂ exceeds a preset upper limit value in step 114 is determined.

When the current value A ₂ does not exceed the upper limit value, step
Whether or not a current value A ₂ is smaller than the lower limit value is determined at 115.

If the current value A ₂ is larger than the lower limit, calculation of the current value A _2, S ₂ is performed in step 116, then the determination in step 114 is performed again. As is clear from this, the current value
A ₂ is greater than smaller lower limit than the upper limit value is carried out hot water supply by two gas water heaters 10, 20.

When the current value A ₂ is smaller than the lower limit, the solenoid valve 62
Is closed (step 110) and the gas water heater 20 is closed.
Is stopped (step 111). As a result, gas water heater 1
Hot water supply with only 0 is performed.

Here, the reason for the existence of step 113 will be described.
The upper limit of the current value A ₂ is the opening of the electromagnetic proportional control valve 27 90% to 95%
It is set to the current value to be about, the lower limit is 80-85%
The degree is determined. The setting rotational speed of the fan 28, the current value A ₂ is set to the rotational speed such that the magnitude between the upper and lower limit values.

Incidentally, the operation beginning of the gas water heater 20 is low rotational speed of the fan 28, the current value A ₂ is smaller than the upper limit value and the lower limit value correspondingly. Therefore, if assuming step 113 is no, because the current value A ₂ is less than become not lower limit only the upper limit value, so that the gas water heater 20 after the start of operation, will be stopped immediately. Step 113 is provided to eliminate such inconvenience.

In step 114, if the current value A ₂ is determined to be larger than the upper limit value, the electromagnetic on-off valve 63 is opened (step 117), a gas water heater 30 is activated (step 118).

Next, in step 119, it is determined whether or not the amount of water supplied to the gas water heater 30 is larger than the minimum operation flow rate.

When the water supply amount is smaller than the minimum operation flow rate, the electromagnetic on-off valve 37 is closed (step 120), and the gas water heater 30 is stopped (step 121). And step 1
Return to 09. Therefore, hot water is supplied again by the two gas water heaters 10, 20.

If the water supply is greater than the minimum working flow rate,
Current A ₃ to the electromagnetic proportional control valve 37 is calculated in two. This calculation is based on water supply temperature Tc ₃ , water supply amount W ₃ , hot water supply temperature T
Based on h ₃ and the target temperature Th _0, it is performed in the same manner as the gas water heater 10. Of course, the driving current S ₃ at this time is also calculated. The fan with the rotation speed corresponding to the driving current S ₃
38 with being rotated is the electromagnetic proportional control valve 37 is opened to the opening degree corresponding to the current value A _3.

Next, in step 123, it is determined whether or not the rotation speed of the fan 38 is larger than the set rotation speed. The significance of this determination is the same as in step 113.

If the rotation speed of the fan 38 is smaller than the set rotation speed, the process returns to step 119.

If the rotation speed of the fan 38 is higher than the set rotation speed,
Whether the current value A ₃ is smaller than the lower limit value is determined. The lower limit is set to a value when the opening of the electromagnetic proportional control valve 37 is set to about 80 to 85%.

Is larger than the lower limit value, the current value A ₃ is calculated in step 125 is performed again determined in step 124. That is, unless the current value A ₃ not smaller than the lower limit value, is performed hot water supply by three gas water heaters 10, 20, 30.

If the current value A ₃ is smaller than the lower limit value, step 120,
121 is executed. That is, the gas water heater 30 is stopped. As a result, hot water is supplied by the two gas water heaters 10, 20.

As described above, in this gas water heater, the second gas water heater 20 does not operate until the current value A ₁ for the electromagnetic proportional control valve 17 of the first gas water heater 10 reaches the upper limit value. First, hot water is supplied only by the first gas water heater 10. Therefore, by previously setting a high upper limit for the current value A _1, as indicated by a solid line in FIG. 3 1
The temperature of the hot water discharged from the second gas water heater 10 can be made to reach the stable temperature range, whereby the time until the hot water supply temperature reaches the stable temperature range can be shortened.

As is clear from the above description, the current values A ₁ and A ₂ for the electromagnetic proportional control valves 17 and 27 and the drive currents S ₁ and S _{2 for} the fans 18 and 28 or the rotation speed N _{1 of the} fans 18 and 28 , and corresponds to the N _2. Therefore, the number of used motors may be switched according to the magnitude of the drive currents S ₁ and S ₂ or the rotation speeds N ₁ and N ₂ . In such a case, in steps 104, 114, 115 and 124 of the flowchart shown in FIG. 2, the drive currents S ₁ and S ₂ are compared with the upper limit value or the lower limit value, or the rotational speeds N ₁ and N _{1 It} is sufficient to compare ₂ with the upper limit value or the lower limit value thereof. As is apparent from this point, the physical quantity related to the rotation speed of the fan in the present invention is the rotation speed of the fan or the current value supplied to the fan. Of course, drive current
The above-described effect can be obtained even if the number of units used is switched according to S ₁ , S ₂ or the rotation speeds N ₁ , N ₂ .

It should be noted that the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist thereof.

For example, in the above-described embodiment, three gas water heaters 10, 20, and 30 are controlled by one control unit 80. However, control units are installed in each of the gas water heaters 10, 20, and 30, respectively. You may.

Further, in the above embodiment, the feed water temperatures Tc ₁ , Tc ₂ , Tc
_3, the water supply amount W _1, W _2, W _3, and based on the target temperature Th _0, but by calculating the current value A _1, A _2, A ₃ and the drive current S _1, S _2, S _3, The current values A ₁ , A ₂ , A ₃ and the drive currents S ₁ , S ₂ , S ₃ may be calculated based on the target temperature Th ₀ and the hot water supply temperatures Th ₁ , Th ₂ , Th ₃ .

[Effects of the Invention] As described above, according to the gas water heater of the present invention, when the physical quantity related to the rotation speed of the fan of the first gas water heater exceeds a set value, or when the current value to the electromagnetic proportional control valve is increased. When the temperature exceeds a predetermined set value, the on-off valve is opened. Therefore, before the second and subsequent gas water heaters operate, the temperature of the hot water discharged from the first gas water heater is reduced. The temperature can be raised to the stable temperature range, and the time required to reach the stable temperature range can be shortened.

[Brief description of the drawings]

1 and 2 show one embodiment of the present invention. FIG. 1 is a diagram showing a schematic configuration thereof, and FIG. 2 is a diagram showing a flowchart of a program for switching the number of gas water heaters to be used. FIG. 3 is a diagram showing the hot water supply temperature by the gas hot water supply apparatus of the present invention and the hot water supply temperature by the conventional gas hot water supply apparatus. 10,20,30… Gas water heater, 16,26,36… Burner 17,27,37… Electromagnetic proportional control valve 18,28,38… Fan 62,63… Electromagnetic on-off valve (on-off valve) 80 ... Control unit.

Continuation of the front page (56) References JP-A-64-63748 (JP, A) JP-A-64-41844 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F24H 1 / 10 F24D 17/00

Claims (2)

(57) [Claims] 1. An n (n ≧ 2) gas water heater connected in parallel with each other, an on-off valve installed on the water supply side of (n-1) gas water heaters, and an on-off valve for opening and closing The gas water heater has a burner for heating the supplied water, an electromagnetic proportional control valve for adjusting the amount of gas supplied to the burner, and a fan for supplying air to the burner. In the gas water heater configured to limit the current to the electromagnetic proportional control valve in accordance with the number of rotations of a fan, the control unit includes: N (N = 1, 2,..., N−1) A) physical quantity detecting means for detecting that a physical quantity relating to the rotation speed of the fan of the gas water heater exceeds a set value, and opening the (N + 1) th opening / closing valve based on a detection signal of the physical quantity detecting means. A gas water heater comprising a valve means. 2. An n (n.gtoreq.2) gas water heater connected in parallel with each other, an on-off valve installed on a water supply side of (n-1) gas water heaters, and an on-off valve for opening and closing the on-off valve The gas water heater has a burner for heating the supplied water, an electromagnetic proportional control valve for adjusting the amount of gas supplied to the burner, and a fan for supplying air to the burner. In the gas water heater configured to limit the current to the electromagnetic proportional control valve in accordance with the number of rotations of a fan, the control unit includes: N (N = 1, 2,..., N−1) Current value detecting means for detecting that the current value supplied to the electromagnetic proportional control valve of the gas water heater exceeds a set value; and (N + 1) th opening / closing based on the detection signal of the current value detecting means. And a valve opening means for opening the valve.