JPH0150826B2 - - Google Patents

Description

[Detailed description of the invention] The present invention is based on the combustion capacity of the gas burner, the amount of water that can be heated to the set temperature from the set temperature, etc. (hereinafter referred to as the control water amount Q ₀
This invention relates to an instantaneous water heater that is capable of dispensing hot water at a set temperature by calculating the amount of water Q ₀ and adjusting the opening degree of a water control valve installed in a water channel so that the controlled water amount Q 0 is obtained.

To explain this instantaneous water heater based on FIG. 1, 1 is a heat exchanger, 2 is a gas burner that heats the heat exchanger 1, and the gas burner 2 has a plurality of burner elements 2a, 2b, 2c, 2d, 2e. The gas passages 3 leading to these burner elements 2a to 2e are branched from the downstream of the original solenoid valve 4, and each branch gas passage 3a, 3b, 3c, 3d, 3e has a solenoid valve 5.
a, 5b, 5c, 5d, and 5e are interposed. 6
8 is a water quantity detector provided in the water supply channel 7 leading to the heat exchanger 1, and 8 is a water supply temperature detector. 9 is a water control valve controlled by a controller described later. 10 is a hot water tap. Reference numeral 11 denotes a remote controller installed in a place where hot water is used, such as the kitchen.
2. A temperature setting device 13 and an operation switch 14 are provided to adjust the hot water temperature. 15 is a controller.

Next, the general configuration of the above controller will be explained based on FIG. temperature
Tin, the water flow rate Q from the water flow rate detector 6, and the setting capacity signal and set temperature Tset from the remote controller 11 are input. The capacity setting device 12 changes settings from position a to position d.
By switching to the position, the number of burning elements of the burner element is set to 5, 3, 2, 1, and the switching capacity is set to, for example, 16.5, 10, 6.6, or 3.3. At the same time, the calculation control unit At 16, a combustion amount signal (hereinafter referred to as setting capacity W) corresponding to the number of combustion cylinders is output.

The operation of such an instantaneous water heater is as follows.
When water is passed through the water supply channel 7 by opening the hot water tap 10, the amount of water flowing is detected by the water amount detector 6, and if this detected water amount Q is above a certain amount (for example, 2/min), the arithmetic control unit 16 It is determined that the hot water tap 10 has been opened, and a predetermined combustion sequence is started. Simultaneously with the start of combustion, the arithmetic control section 16 calculates the controlled water amount Q ₀ using the formula Q ₀ = 25 x W/(Tset - Tin), and sends signals of the controlled water amount Q ₀ and the detected water amount Q to the servo motor drive circuit 17. The amount of water is adjusted by outputting an output and controlling the opening degree of the water control valve 9 via the servo motor 18.

By the way, in this type of instantaneous water heater that adjusts the amount of water to obtain hot water at a set temperature, a minimum operating water amount (hereinafter referred to as the first set water amount Q1) is determined in consideration of safety, and the detected water amount Q is set at the first set temperature. If the amount of water falls below the 1 set level, it is necessary to stop combustion. Further, this first set water amount Q1 changes depending on the set capacity W and the water supply temperature Tin, and therefore needs to be determined by the following formula.

Q1=25×W/(85−Tin) Furthermore, as mentioned above, the first set water amount Q1 changes depending on the set capacity W, so when changing the capacity or setting the set temperature Tset to the high temperature side. When switching to , the detected water amount Q may temporarily become less than the water amount Q1 due to the control delay of the water control valve 9, etc.
Therefore, even if the amount of water falls below Q1, it is necessary not to immediately extinguish the fire, but to wait for the water amount to recover for a certain period of time before determining whether or not the fire can be extinguished.

However, if we wait for the amount of water to recover in this way, even if the hot water tap 10 is closed, combustion will continue for a certain period of time. 2 It is necessary to set a set water volume Q2 and extinguish the fire immediately when the water volume falls below the set water volume.

In addition, in order to stabilize the control, a fixed ratio (however, α
>1) Set the multiplied third set water volume Q3, and if the water volume does not recover to the third set water volume Q3 within the above-mentioned fixed time, it is necessary to extinguish the fire.

As mentioned above, in this type of instantaneous water heater, the first set water volume Q1, the third set water volume, etc.
Set by varying the set water amount Q3.

Even if the detected water amount Q becomes less than the first set water amount Q1, combustion continues for a certain period of time, and if the water amount Q does not recover to the third set water amount Q3 or more, the fire is extinguished.

When the detected water amount Q becomes less than the second set water amount, the fire is extinguished immediately.

It is necessary to control.

However, when the above-mentioned control is performed, if the setting capacity W is set to a relatively high temperature on the small side, for example, W=
When setting No. 3.3, Tin=15℃, Tset=65℃,
The controlled water flow rate Q ₀ is 1.65/min, so the opening degree of the water control valve 9 is adjusted so that the water flow rate is 1.65/min.
8 or the like, the water volume temporarily becomes less than the second set water volume Q2, which is the water volume for determining closure, and the fire is extinguished, making it impossible to release hot water, or controlling the water control valve 9 to open when the fire is extinguished. Even if you do this, you will have to repeat the extinguishing process.

As a solution to the above problems, control water flow
Set Q ₀ to have a certain difference in water amount from the second set water amount Q2, that is, Q ₀ Q2 + A (A is a constant, for example
If the correction is made to satisfy 1.2), the second set water volume Q2 will be maintained even if the servo motor 18 etc. overruns a little.
The water volume does not drop below that level, the valve is determined to be closed, and the fire is not extinguished. In this case, hot water at the set temperature Tset cannot be obtained, but this does not pose a problem in use since the water volume is not within the actual water volume range.

However, even if the above configuration is adopted, for example, the supply water temperature
When Tin is 10℃, W=6.6, and Tset is set to 75℃, Q1=2.2/min, Q3=2.8/min (however, α
= 1.25), Q ₀ = 2.5/min, and as shown in Figure 4, for the same reason as above, the second set flow rate may not be lower than Q2, but it may be lower than the first set flow rate Q1. If the water volume is not restored to the third set water volume Q3, the fire will be extinguished even if the water volume is adjusted to the control water volume _Q0 , which poses a problem in use.

The present invention aims to solve the above problems, and will be described below based on an embodiment shown in the drawings. FIG. 5 is a block circuit diagram of the calculation control section 16 in the present invention, and the water amount calculation section 161 is connected to the water amount detector 6.
This water amount signal is outputted to the water amount determining section 162 and the servo motor drive circuit 17. Water amount determination unit 162
For example, when the water amount is 2/min or more, a signal to start combustion is output to the combustion control circuit 22, and when it is less than 1.5/min, which is the second set water amount Q2, a signal to stop combustion is output. Furthermore, the control water amount calculation section 1
63, the water volume is compared with the first set water volume Q1 and the third set water volume Q3 calculated together with the control water volume _Q0 , and if the water volume becomes less than the first set water volume Q1, the counter is activated and the water volume reaches the third setting within a certain period of time. If the water quantity does not recover to Q3, a combustion stop signal is output at the same time as the counter is raised. The water amount correction section 164 is the control water amount calculated by the control water amount calculation section 163.
Q ₀ ′ is corrected under certain conditions, and the control water amount
Q ₀ ' is a fixed amount (for example, 1.2/
min) If the added water volume is less than the added water volume (for example, 2.7/min, this is referred to as the 4th set water volume Q4), the control water volume
Q ₀ is set as the fourth set water volume Q4, and if the water volume is equal to or higher than the above-mentioned control water volume Q ₀ ' and is lower than the third set water volume Q1, the water volume is set to the same water volume as the third set water volume Q1, or the same water volume or more, and in other cases. is directly outputted to the servo motor drive circuit 17 as the controlled water amount _Q0 . For example, if the water supply temperature Tin is 10℃, the setting capacity W
is No. 6.6 and the set temperature Tset is 75℃, the control water amount
Q ₀ is set to 2.8/min, which is the same water volume as the third set water volume Q3.

Therefore, according to this configuration, the controlled water amount Q ₀ is set to be equal to or greater than the water amount obtained by adding a certain amount to the second set water amount Q2, which is the water amount for determining closing, and is set to be equal to or greater than the third set water amount Q3. There is no possibility that the valve 9 is judged to be closed due to overrun etc. when controlling the valve 9, and there is no longer a situation where the water level falls below the first set water level Q1 and does not recover to the third set water level Q3 or higher, and therefore, the fire cannot be extinguished unexpectedly. This prevents deterioration of the hot water supply characteristics.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an instantaneous water heater according to the present invention,
Figure 2 is a control circuit diagram of a simultaneous water heater, Figures 3 and 4 are explanatory diagrams showing changes in water volume during water volume control in a conventional example, and Figure 5 is a controller showing an embodiment of the present invention. FIG. DESCRIPTION OF SYMBOLS 1... Heat exchanger, 2... Gas burner, 8... Water supply temperature detector, 9... Water control valve, 12... Capacity setting device, 15... Controller, 164... Water amount correction part.

Claims (1)

[Claims] 1. A heat exchanger, a gas burner with variable capacity to heat the heat exchanger, a water control valve, a capacity setting device to switch the capacity of the gas burner, and a temperature setting device that changes the temperature of the water supply from the water supply temperature detector, the set temperature, and the capacity setting device. a controller that calculates a control water flow rate and a minimum operating water flow rate based on a set capacity, and controls the water control valve to achieve the control water flow rate, the control water flow rate being determined as the minimum operating water flow rate and a preset closure determination. An instantaneous water heater characterized by being provided with a water amount correction section that corrects the amount of water so that it has a constant difference in water amount.