JP2526472B2 - Water heater - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a water amount adjusting valve and a water amount detecting device, and the water amount detecting device is a minimum operating water amount (MOQ).
Regarding the water heater to check.

[0002]

2. Description of the Related Art Conventionally, a water amount detecting device for detecting the amount of water flowing into a heat exchanger, and a water temperature detecting device for detecting an incoming water temperature,
Equipped with a hot water temperature detection device that detects the temperature of the hot water that flows out, and a water amount adjustment valve that adjusts the water flow rate.The water amount adjustment valve during steady operation based on the inflow water amount, the incoming water temperature, the set temperature, and the heating capacity of the heater. In the water heater that sets the required opening of the hot water supply valve, the opening of the water quantity adjusting valve is fixed at the initial opening smaller than the required opening when the hot water is started, and the water quantity adjusting valve is adjusted according to the rise of the hot water temperature. Gradually increase the opening degree of
There is known a control method of shifting to a steady operation when the set opening is reached (for example, see Japanese Patent Laid-Open No. 1-302063).

[0003]

However, in the above-mentioned conventional water heater control method, since the opening of the water quantity adjusting valve is fixed at the initial opening smaller than the set opening at the beginning of hot water discharge, When the minimum working water pressure MOP required to pass the minimum working water amount MOQ becomes high and the supply water pressure drops, the water heater cannot reach the minimum working water amount MOQ required to reliably start hot water discharge. There was a problem. Further, there is a method of ensuring a minimum working water amount MOQ even when the supply water pressure is low by detecting a minute flow rate (eg, 1 l / min.) Or more sufficiently smaller than the minimum working water amount MOQ and opening the water amount adjusting valve. However, for example, if there is an air pool on the upstream side of the water amount detection device when the hot water is stopped, when the water amount adjustment valve moves in the opening direction, the water on the downstream side of the water amount detection device and the air pool on the upstream side are replaced. Since the drooping phenomenon occurs and the water amount detection device cannot determine the flow direction, there is a risk that the water flow that flows backward from the downstream side of the water amount detection device to the upstream side is detected, and the water amount adjustment valve is fully opened and waits.

An object of the present invention is to provide a water heater having a water quantity adjusting valve, which can secure a minimum working water quantity even at a low water pressure without increasing the minimum working water pressure.

[0005]

In order to achieve the above object, a water heater according to the present invention is provided with a water amount detecting device and a water amount adjusting valve in a water passage connected to a heat exchanger, and the water amount adjusting valve after the hot water is stopped. In the water heater that controls the opening of the hot water to a predetermined standby position and enters the standby state, the operation to start the hot water re-opening operation after the hot water is stopped
When it is confirmed that the flow rate Q is a predetermined minute flow rate Q _MIN or more and less than the minimum operating water amount MOQ for a predetermined determination time t ₁ , the water amount adjusting valve is driven in the opening direction. Then, when the flow rate Q is increased and the flow rate Q reaches the minimum operating water amount MOQ, a control means for starting the hot water discharge operation is provided, and the minimum operating water pressure MOP is not increased, and the minimum operating water pressure is also obtained. A water amount MOQ can be secured.

[0006]

Embodiments of the present invention will be described with reference to the drawings. In FIG. 1, a water heater 1 to which the present invention is applied includes a heat exchanger 2
A water inlet 3 connected to the inlet side of the heat exchanger 2, a hot water outlet 4 connected to the outlet side of the heat exchanger 2, a gas burner 5 composed of two burner elements 51 and 52, and a burner element. 51, 52
Gas control valves 71 and 72 installed in the gas pipelines 61 and 62 respectively connected to the gas pipes 61 and 62, and a proportional control valve 7 and a main valve arranged in the gas source pipeline 6 to which both the gas pipelines 61 and 62 are joined. 8, the incoming water temperature sensor 10 for detecting a disposed above fill water channel 3 input water Q water sensor 9 and the incoming water temperature _C detects the T _C,
Hot water temperature sensor 11 for detecting a hot water temperature T _H is provided in the tapping passage 4, the flow rate (= Q _C) an over-spill prevention function equipped water control valve 12 and the hot-water tap 16 for controlling the amount of water sensor 9 and the incoming water temperature A bypass passage 13 that connects the water inlet 3 of the sensor 10 on the heat exchanger 2 side to the hot water outlet temperature sensor 11 and the hot water outlet 4 of the water amount adjusting valve 12 on the heat exchanger 2 side and a combustion fan 14 are provided.

The amount of water input Q _C detected by the water amount sensor 9,
And the incoming water temperature T _C detected by the incoming water temperature sensor 10, a hot water temperature T _H detected by the hot water temperature sensor 11 is input to the controller 15 comprising a microcomputer or the like, in the controller 15, input water Q _C, thereby calculating the required quantity of heat G _FF in the steady operation of the gas burner 5 based on the set temperature T _S set incoming water temperature T _C and advance, the correction amount of heat G _FB on the basis of the deviation between the set temperature T _S and the hot water temperature T _H The calculation is performed, and a drive signal is output to the water flow control valve with overflow prevention function 12, the gas control valves 71 and 72, the proportional control valve 7, and the main plug 8.

Next, the operation will be described with reference to FIG. Figure 2a shows the fluctuation of the flow rate Q (l / min.), And Figure 2b shows the controller.
The count value of the counter built in 15 is shown, and when the flow rate Q within a predetermined range is detected, it is counted down from the initial value to zero and the elapse of the determination time t ₁ is confirmed. In this embodiment, the initial value is 10 1 count sampling time
Since it is set to 0.1 sec / time, the judgment time t ₁ = 1 second, and FIG. 2c shows the opening degree of the water flow control valve with overflow prevention function 12, and when tapping is stopped at time t _OFF , the flow rate is Q becomes zero from the set flow rate in the steady hot water discharge operation (Fig. 2
a), the water flow control valve with overflow prevention function 12 is driven in the closing direction, reaches a predetermined intermediate position (standby position) at time t _CL , and is held at that position.

At a time t _CH after a lapse of the waiting time t ₂ from the time t _OFF , the flow rate Q is a predetermined minute flow rate Q _MIN (for example, 0.5 l / min.) Or more and the minimum working water amount MOQ (for example,
Initial flow rate less than 2.16l / min.) Q ₁ (Q _MIN ≤ Q ₁ <MO
Q) (Fig. 2a) is detected by the water amount sensor 9,
The counter built in the controller 15 starts counting down from the initial value (10) (Fig. 2b), and at time t _ON , the count value of the counter becomes zero and it is confirmed that the judgment time t ₁ (1 second) has passed. When the flow rate Q = Q ₁ is continued until the flow rate is reached, it is determined that the water flow due to the hot water discharge start operation is detected, and the overflow prevention water flow rate adjustment valve 12 is driven in the opening direction.
The flow rate Q is increased so that at the time t _S , the flow rate Q becomes the minimum working water amount M.
When it reaches OQ, the hot water discharge operation is started.

With this configuration, it is possible to reliably obtain the minimum working water amount MOQ at the start of tapping without increasing the minimum working water pressure MOP when obtaining the minimum working water amount MOQ. The waiting time t ₂ is a predetermined value (for example, 5 seconds)
In the following cases, the counter does not count down and holds the initial value (10), so that it is possible to prevent erroneous detection of the water amount sensor 9 due to the accumulation of air at the time of water stoppage or dripping. Further, the rest time t ₃ (t ₃ ) from the time t _OFF to the time t _{ON
When 3} = t ₁ + t ₂ ) exceeds a prescribed time (for example, 10 minutes), the water flow rate adjusting valve with overflow prevention function 12 is put in the fully open position to ensure a minimum when starting hot water after a long stop. A working water amount MOQ can be obtained, and usability is improved.

The control operation will be described with reference to the flowchart of FIG. In the steady mode, that is, during the normal hot water discharge operation, the water flow control valve with overflow prevention function 12 performs a normal overflow prevention operation. When the mode is not the steady mode, that is, when the hot water supply is stopped or the amount of water flow is small, the flow rate Q is a predetermined minute flow rate Q _MIN (0.5 l / min.) Or more and the minimum working water volume MOQ.
Initial flow rate less than (2.16 l / min.) Q ₁ (Q _MIN ≤Q ₁ <M
OQ), that is, Q _MIN ≦ Q <MOQ, after confirming that the waiting time t ₂ exceeds a predetermined value (5 seconds),
The counter counts down from the initial value (10) to zero, and when it reaches zero, the elapse of the determination time t ₁ (1 second) is confirmed, the counter is reset, and the flow rate at which hot water starts is detected. When the judgment is made, the water flow control valve with overflow prevention function 12 is driven in the opening direction, and when it reaches the fully open position, it returns to the first operation, and when the flow rate Q becomes equal to or more than the minimum working water amount MOQ before reaching the fully open position ( Q ≧ MOQ), the flow rate Q is controlled to a predetermined initial flow rate Q ₂ (MOQ or more and less than the set flow rate or less than the required flow rate), and the hot water outlet temperature T _H is quickly increased, and then a predetermined set time elapses. The operation shifts to the overflow prevention operation.

Further, when the flow rate Q is not equal to the initial flow rate Q ₁ (Q _MIN ≤Q ₁ <MOQ) and is not less than the minimum working water amount MOQ (Q ≧ MOQ) in the non-steady mode, the flow rate Q is After controlling the initial flow rate Q ₂ to quickly raise the hot water outlet temperature T _H , a normal overflow prevention operation is performed after a lapse of a predetermined set time. On the other hand, the flow rate Q is the minimum working water amount MO.
It is less than Q, that is, the flow rate Q is a minute flow rate Q _MIN (0.5 l / mi
If it is less than n.), it is determined that the hot water supply is stopped,
The water flow control valve 12 with the overflow prevention function is returned to the standby position to enter the standby state. In the above embodiment, the counter counts down from the initial value to zero and the determination time t
_Although the progress of ₁ has been confirmed, it is not limited to the counter, and a normal timer can be used.

[0013]

Since the present invention is configured as described above, the following effects can be obtained. After the hot water supply is stopped, the opening of the water flow control valve is controlled to a predetermined standby position to enter the standby state.In a water heater that has exceeded a predetermined minute flow rate and has detected a water flow rate that is equal to or less than the minimum operating water volume, a predetermined judgment is made. By driving the water amount adjusting valve in the opening direction when the hot water discharge operation is performed when the time has continued, the minimum working water amount can be secured even at low water pressure without increasing the minimum working water pressure.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a water heater according to an embodiment of the present invention.

FIG. 2A is a graph showing a change in flow rate, FIG. 2B is a count value of a counter, and FIG. 2C is a graph showing a change in opening of a water amount adjusting valve with an overflow prevention function.

FIG. 3 is a flowchart showing a control operation of a water amount adjustment valve with an overflow prevention function.

[Explanation of symbols]

1 water heater, 2 heat exchanger, 3 water inlet, 4 outlet,
5 Burner 6 Gas main line, 7 Proportional control valve, 8 main tap, 9 Water inlet sensor 10 Water inlet temperature sensor, 11 Hot water outlet temperature sensor, 12 Water amount adjusting valve 13 Bypass passage, 14 Combustion fan, 15 Controller (control means) , 16 hot water taps

Claims (1)

(57) [Claims] 1. A water passage connected to a heat exchanger is provided with a water amount detecting device and a water amount adjusting valve, and after the hot water is stopped, the opening of the water amount adjusting valve is controlled to a predetermined waiting position opening degree to enter a standby state. In the water heater, the operation to start the hot-water discharge again is performed after the hot water is stopped.
When it is confirmed that the flow rate Q is equal to or more than the predetermined minute flow rate Q _MIN and is less than the minimum operating water amount MOQ for the predetermined determination time t ₁ , the water amount adjusting valve is driven in the opening direction, Increase the flow rate Q so that the flow rate Q is the minimum working water volume MOQ.
The water heater having a control means for starting the hot water discharge operation.