JPH0346741B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a water heating burner and a heat exchanger, a water supply temperature sensor for detecting the temperature of water supplied to the heat exchanger, and a water supply temperature sensor for detecting the temperature of water supplied to the heat exchanger. A water flow control valve for adjusting the amount of water supplied to the heat exchanger and a water flow sensor for detecting the amount of water supplied to the heat exchanger are provided, and the heating capacity, the water supply temperature detected by the water supply temperature sensor, and the set hot water temperature are determined. Based on this, a target water supply amount is calculated so that the hot water supply temperature from the heat exchanger is set to the set water supply temperature, and the water flow control valve is controlled so that the water supply amount detected by the water flow sensor becomes the calculated target water supply amount. The present invention relates to a water heater equipped with water flow control means.

[Conventional technology]

Conventionally, in water heaters such as those mentioned above, the supply pressure of fuel gas to the burner,
In other words, since there are variations in the supply amount and this causes the actual heating capacity to fluctuate, the hot water supply temperature is set to the set hot water temperature based on the predetermined heating capacity of the water heater, the detected water supply temperature, and the set hot water supply temperature. Even if the target water supply amount is calculated and the water supply amount is controlled so that the detected water supply amount becomes the calculated target water supply amount, the hot water supply temperature may not be able to reach the set hot water supply temperature.

Therefore, a hot water temperature sensor is installed, and the actual heating capacity is calculated from the water supply temperature detected by the water supply temperature sensor, the water supply amount detected by the water flow sensor, and the hot water temperature detected by the hot water temperature sensor. The target water supply amount is calculated based on the corrected heating capacity, the detected hot water supply temperature, and the set hot water supply temperature, and the water flow control valve is controlled so that the detected water supply amount becomes the target water supply amount. There are some that do this (for example, Japanese Patent Application Laid-Open No. 60-207847
(See Japanese Patent Application Laid-Open No. 1983-20786).

[Problem to be solved by the invention]

However, in the conventional method, the actual heating capacity is calculated from the water supply temperature detected by the water supply temperature sensor, the water supply amount detected by the water flow sensor, and the hot water temperature detected by the hot water temperature sensor, but there are variations in detection accuracy. The large detection error of the water flow sensor affects the entire actual heating capacity as described above, so the error in the calculated actual heating capacity is large. Even though the calculated actual heating capacity is corrected and the amount of water supplied is controlled based on the corrected heating capacity, there is a problem in that the hot water supply temperature cannot be precisely matched with the set hot water supply temperature.

An object of the present invention is to minimize variations in hot water supply temperature caused by detection errors of a water amount sensor by performing rational heating capacity correction.

[Means to solve the problem]

A first feature of the water heater according to the present invention is that it is provided with a burner for heating water and a heat exchanger, and includes a water supply temperature sensor that detects the temperature of water supplied to the heat exchanger, and a water supply temperature sensor that detects the temperature of water supplied to the heat exchanger. A water flow control valve for adjusting
A water amount sensor is provided to detect the amount of water supplied to the heat exchanger, and the hot water supply temperature from the heat exchanger is set based on the heating capacity, the supplied water temperature detected by the supplied water temperature sensor, and the set hot water supply temperature. A water supply temperature sensor that detects a hot water supply temperature in a configuration including a water flow rate control means that calculates a target water supply volume at a temperature and controls the water volume control valve so that the water supply volume detected by the water volume sensor becomes the calculated target water supply volume. is provided, and based on the temperature deviation between the hot water temperature detected by the hot water temperature sensor and the set hot water temperature, and the water supply amount detected by the water flow sensor, calculate the excess or deficiency of the actual heating capacity with respect to the heating capacity. , a capacity correction means is provided for correcting the heating capacity by the calculated excess or deficiency.

Further, a second characteristic configuration of the water heater according to the present invention is that the capacity correction means is adjusted to the hot water temperature sensor after the water flow control valve is controlled by the water flow control means based on the corrected heating capacity. Based on the temperature deviation between the hot water supply temperature detected by the sensor and the set hot water supply temperature, and the water supply amount detected by the water flow sensor, the excess or deficiency of the actual heating capacity with respect to the corrected heating capacity is calculated, and the excess or deficiency of the calculated excess or deficiency is calculated. The heating capacity corrected above is re-corrected by that amount, and its functions and effects are as follows.

[Effect]

In the first characteristic configuration of the present invention, a temperature deviation between the hot water temperature detected by the hot water temperature sensor and the set hot water temperature;
And, based on the water supply amount detected by the water amount sensor,
The excess or deficiency of the actual heating capacity with respect to the heating capacity used as the calculation standard for the target water supply amount is calculated, and the heating capacity is corrected by the calculated excess or deficiency.

Therefore, since the detection error of the water sensor only affects the excess or deficiency of the actual heating capacity relative to the heating capacity, the correction error due to the detection error of the water quantity sensor is reduced in the heating capacity correction, compared to the conventional correction method described above. becomes smaller.

In the second characteristic configuration of the present invention, the hot water temperature detected by the hot water temperature sensor and the set hot water temperature after the water flow control valve is controlled by the water flow control means based on the heating capacity corrected by the first characteristic configuration. Based on the temperature deviation of , and the water supply amount detected by the water amount sensor, the excess or deficiency of the actual heating capacity with respect to the corrected heating capacity is calculated, and the corrected heating capacity is re-corrected by the calculated excess or deficiency. do.

Therefore, since the heating capacity that has been corrected once is re-corrected, and the correction error caused by the detection error of the water amount sensor in the re-correction is also small, similar to the effect of the first characteristic configuration described above, the correction error of the heating capacity correction is becomes even smaller.

[Effects of the Invention] As a result, according to the first characteristic configuration of the present invention,
It has now been possible to provide a water heater that can accurately adjust the hot water supply temperature to the set hot water temperature even when there is a detection error in the water flow sensor as well as variations in the amount of fuel gas supplied.

Moreover, if the second characteristic configuration of the present invention is adopted,
The hot water supply temperature can be set with even higher accuracy.

〔Example〕

Next, examples of the present invention will be described.

As shown in FIG. 1, it is an instantaneous water heater equipped with a burner 1 for heating water, a heat exchanger 2, and a controller 3. A safety valve 6 and a gas valve 7 for adjusting the amount of gas supplied are interposed.

The water supply channel 8 to the heat exchanger 2 has a temperature of the water supply.
A water supply temperature sensor 9 that detects Ti and a water amount sensor 10 that detects the amount of water supply Qn are interposed.

A hot water supply path 12 from the heat exchanger 2 to the hot water tap 11 includes a hot water temperature sensor 13 for detecting the hot water temperature To;
A water flow control valve 14 for adjusting the water supply amount Qn (hot water supply amount) is interposed.

The controller 3 opens the main valve 5 and the safety valve 6 and turns on the igniter 16 for the ignition plug 15 of the burner 1 when the water amount sensor 10 detects a water amount above a certain level when the hot water tap 11 is opened.
ignition control that operates for a set time, extinguishing control that closes the main valve 5 and safety valve 6 when the water volume sensor 10 detects a water volume below a certain level when the hot water tap 11 is closed, and detects the combustion flame of the burner 1. In addition to the basic control of the fire breakout control which closes the safety valve 7 due to non-detection due to the fire breakage of the flame rod 17, hot water supply temperature control is performed.

The hot water supply temperature control is performed by a gas amount control means 18 and a water amount control means 19.

The gas amount control means 18 includes the water amount sensor 1
When the water supply amount Qn detected at 0 is the maximum hot water supply amount in the maximum rated capacity range, the hot water supply temperature To detected by the hot water temperature sensor 13 and the set hot water temperature
This means proportionally controls the gas valve 7 based on the temperature deviation ε _o from Ts so that the heating capacity is such that the hot water supply temperature To becomes the set hot water supply temperature Ts.

As shown in FIG.
When To cannot reach the set hot water supply temperature Ts, that is, as shown in Fig. 4, even if the gas valve 7 is fully opened and the heating capacity W is maximized, the hot water supply temperature
When To cannot reach the set hot water temperature Ts, the heating capacity W, the water supply temperature Ti detected by the hot water temperature sensor 9, the water supply amount Qn detected by the water flow sensor 10, and the set hot water temperature Ts Based on this, as shown in FIG. 5, it is a means for controlling the water amount regulating valve 14 so that the water supply amount Qs (target water supply amount) that makes the hot water supply temperature To become the set hot water supply temperature Ts. Then, the temperature deviation ε _o and the water amount sensor 10
It has a capacity correction means 20 which calculates the excess or deficiency of the actual heating capacity with respect to the heating capacity W based on the detected water supply amount Qn, and corrects the heating capacity W by the calculated excess or deficiency.

Next, the water amount control means 19 will be specifically explained in step order based on FIG.

Step 1 (#1) Initialize the heating capacity W to the maximum heating capacity. The maximum heating capacity may be the design maximum heating capacity, but it should be slightly larger than the design maximum heating capacity (approximately 115% of the design maximum heating capacity) in consideration of variations in various sensors. is desirable.

Step 2 (#2) Initially set heating capacity W and set hot water temperature
Ts and the feed water temperature Ti detected by the feed water temperature sensor 9
Based on Equation [1], the target water supply amount Qs that makes the hot water supply temperature To become the set hot water supply temperature Ts is calculated.

Qs=W/(Ts-Ti)...[1] Step 3 (#3) Temperature deviation between hot water supply temperature To and set hot water supply temperature Ts _o
Check whether is larger than the set temperature deviation ε _s (generally about 1.5 degrees).

Step 4 (#4) If ε _o >ε _s in step 3, it is checked whether the opening degree θ _o of the gas valve 7 is larger than the set opening degree θ _s which is close to fully open.

Step 5 (#5) If θ _o >θ _s in step 4, a count is performed in which 1 is added to the variable N, and the process proceeds to step 7.

Step 6 (#6) If ε _o ≦ε _s in step 3 and θ _o ≦ θ _s in step 4, a count is performed to subtract 1 from the variable N, and the process proceeds to step 7.

Step 7 (#7) Check whether N≧K (constant).

Step 8 (#8) If N≧K in step 7, clear N=0 and calculate the temperature deviation ε _o and the water supply amount detected by the water amount sensor 10 based on equation [2].
Current heating capacity Wn from Qn and previous calculation result
A capacity correction calculation is performed to calculate the heating capacity Wn, and the heating capacity W is updated to the calculated heating capacity Wn, and the process proceeds to step 11.

Wn=W _o-1 − (ε _o +ε _o-1 )/2 × (Q _po + Q _po-1 )/2 ...[2] However, ε _o-1 and Q _po-1 are the previous temperature deviation and It is the water supply amount detected by the water amount sensor 10,
W _o-1 is the heating capacity before updating, that is, the initially set heating capacity or the previously calculated heating capacity.

Step 9 (#9) If N<K in step 7, check whether N≧0, and if N≧0, proceed to step 11.

Step 10 (#10) If N<0 in step 9, clear N=0 and proceed to step 11.

Step 11 (#11) Calculate the water amount deviation ΔQ between the water supply amount Qs and the water supply amount Qn detected by the water amount sensor 10.

Step 12 (#12) Determine whether the water amount deviation △Q is greater than or equal to the first set value K _{1. If △Q≧K 1 ,} proceed to step 13; △Q<
If _K1 , proceed to step 14.

Step 13 (#13) The water flow control valve 14 is opened and operated continuously.

Step 14 (#14) Determine whether the water flow deviation △Q is _greater than or equal to the second set value K2. If △Q≧ _K2 , proceed to step 15; △Q<
If K ₂ , proceed to step 16.

Step 15 (#15) The water flow control valve 14 is opened and operated intermittently.

Step 16 (#16) Determine whether the water flow deviation △Q is larger than the third set value _K3 , and if △Q> _K3 , proceed to Step 17.
If △Q≦K ₃ , proceed to step 18.

Step 17 (#17) The water flow control valve 14 continues its current operation.

Step 18 (#18) Determine whether the water flow deviation △Q is greater _than or equal to the fourth set value K4. If △Q≧ _K4 , proceed to step 19.
If △Q<K ₄ , proceed to step 20.

Step 19 (#19) Stop the water flow control valve 14.

Step 20 (#20) Determine whether the water flow deviation △Q is larger than the fifth set value _K5 , and if △Q> _K5 , proceed to step 21.
If △Q≦K ₅ , proceed to step 22.

Step 21 (#21) The water flow control valve 14 continues its current operation.

Step 22 (#22) Determine whether the water flow deviation △Q is larger than the sixth set value _K6 . If △Q> _K6 , proceed to Step 23.
If △Q≦K ₆ , proceed to step 24.

Step 23 (#23) The water flow control valve 14 is intermittently closed.

Step 24 (#24) The water flow control valve 14 is continuously closed.

Step 25 (#25) After waiting for the set time t, the process returns to step 2.

In short, basically, the heating capacity W is updated every (t×K) seconds, and if the temperature deviation _εo becomes smaller than the set temperature deviation _εs , or the gas valve 7
When the opening degree θ becomes smaller than the set opening degree _θs , the updating of the heating capacity W is delayed by t seconds each time, and step 8 is the capacity correction means 20.

In addition, K ₁ > K ₂ > K ₃ > K ₄ > K ₅ > K ₆ , and K ₁
and K ₆ , K ₂ and K ₅ , and K ₃ and K ₄ are values with opposite signs of + and - and equal absolute values. In addition, to give a specific numerical example, the absolute values of K ₁ and K ₆ are 15% of Q _po ,
The absolute values of K ₂ and K ₅ are 4.5% of Q _po , the absolute values of K ₃ and K ₄ are 1.5% of Q _po , K is 100, and t is 0.1 second.

That is, in this case, the heating capacity W is updated every 10 seconds.

[Another example]

In the above embodiment, a water heater that controls the hot water temperature To by a combination of gas amount control and water amount control is shown, but it goes without saying that the present invention can be applied to a water heater that only performs water amount control.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings by the reference numerals.

[Brief explanation of drawings]

The drawings show an embodiment of the water heater according to the present invention, in which Fig. 1 is a schematic configuration diagram, Fig. 2 is a flowchart, Fig. 3 is a graph showing changes in hot water temperature, and Fig. 4 shows changes in gas valve opening degree. The graph shown in FIG. 5 is a graph showing changes in the amount of hot water supplied. DESCRIPTION OF SYMBOLS 1... Burner, 2... Heat exchanger, 9... Water supply temperature sensor, 10... Water quantity sensor, 13... Hot water supply temperature sensor, 14... Water quantity control valve, 19... Water quantity control means, 20... Capacity Correction means.

Claims (1)

[Claims] 1. A water heating burner 1 and a heat exchanger 2 are provided,
A water supply temperature sensor 9 for detecting the water supply temperature Ti to the heat exchanger 2, a water flow control valve 14 for adjusting the water supply flow rate Qn to the heat exchanger 2, and a water supply flow rate Qn for the heat exchanger 2. The water supply temperature To from the heat exchanger 2 is set based on the heating capacity W, the water supply temperature Ti detected by the water supply temperature sensor 9, and the set water supply temperature Ts. A water heater that is provided with a water flow control means 19 that calculates a target water supply flow rate Qs to be equal to Ts and controls the water flow control valve 14 so that the water flow rate Qn detected by the water flow sensor 10 becomes the calculated target water supply flow rate Qs. In addition, a hot water temperature sensor 13 is provided to detect the hot water temperature To, and the hot water temperature detected by the hot water temperature sensor 13 is
Based on the temperature deviation ε between To and the set hot water supply temperature Ts and the water supply amount Qn detected by the water amount sensor 10, the excess or deficiency of the actual heating capacity with respect to the heating capacity W is calculated, and the calculated excess or deficiency is calculated. A water heater provided with a capacity correction means 20 for correcting the heating capacity W by the amount. 2. The capacity correction means 20 is configured to adjust the hot water supply temperature To detected by the hot water supply temperature sensor 13 and the set hot water temperature after the water volume control valve 14 is controlled by the water volume control means 19 based on the corrected heating capacity W. Based on the temperature deviation ε from Ts and the water supply amount Qn detected by the water amount sensor 10, the excess or deficiency of the actual heating capacity with respect to the corrected heating capacity W is calculated, and the excess or deficiency of the actual heating capacity is calculated by the calculated excess or deficiency. The water heater according to claim 1, which is configured to re-correct the corrected heating capacity W.