JPH0827070B2 - 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 water heater. Specifically, the present invention relates to a bypass mixing type hot water supply device used for dropping hot water into an instantaneous water heater or a bathtub.

[0002]

2. Description of the Related Art FIG . 3 is a schematic block diagram of a conventional bypass mixing type hot water supply apparatus B. In this hot water supply device B, a normally open type bypass side opening / closing valve (electromagnetic opening / closing valve) 53 is provided in the bypass pipe 52 and the bypass pipe 52 of the water inlet pipe 54 connected to the water inlet side of the heat exchanger 51. A normally closed can body side opening / closing valve (electromagnetic opening / closing valve) 55 is provided downstream of the branch point.

Then, when the curran at the end of the pipe is opened,
Water flows only in the bypass pipe 52, the flow rate flowing in the bypass pipe 52 (bypass flow rate) is detected by the flow rate sensor 56, and the can side opening / closing valve 55 is opened only when the flow rate Qt becomes a certain flow rate or more, and the heat exchanger 51. Water flows in. Then, the flow rate sensor 57 detects the flow rate (can flow rate) Qh passing through the heat exchanger 51, and when the flow rate Qh passing through the heat exchanger 51 is equal to or higher than a certain operating flow rate, the gas burner 58 is ignited to set the temperature. Bring out the hot water.

On the other hand, the canal flow rate Qh
Gas burner 5
8 is extinguished, the can side opening / closing valve 55 is fully closed, and when the bypass side opening / closing valve 53 is closed, the bypass side opening / closing valve 53 is fully opened.

[0005]

A water heater B having such a structure
In this case, the can body side opening / closing valve 55 is fully closed during non-combustion to prevent cold water from passing through the heat exchanger and causing low temperature corrosion or the like in the heat exchanger. Therefore, when the bypass side opening / closing valve 53 fails at the fully closed position (for example, when the valve body is stuck in the valve seat and cannot be removed), when non-combustion occurs,
Both the can side opening / closing valve and the bypass side opening / closing valve are fully closed. Therefore, at this time, there is a problem that even if the currant is opened, water does not flow into the flow path on the heat exchanger side or the bypass pipe, the heater does not burn, and the water heater cannot be used. . Similarly, even when the bypass side on-off valve 53 fails to open sufficiently due to a failure, the heater will not burn and hot water will not be discharged from the hot water supply device.

The present invention has been made in view of the above-mentioned drawbacks of the conventional example, and an object thereof is to supply hot water even when the bypass side valve provided in the bypass pipe fails at the fully closed position or the like. It is to be able to supply hot water to the device.

[0007]

In the hot water supply apparatus of the present invention, a water inlet pipe and a hot water outlet pipe are connected to the water inlet side and the hot water outlet side of the heater, respectively, and the heater is bypassed to connect the water inlet pipe and the hot water outlet pipe. A bypass pipe is connected between them, and a bypass valve is provided in the bypass pipe, and a heater is provided between the inlet pipe downstream of the bypass pipe branch and the hot water outlet pipe upstream of the junction. A side valve is provided to bypass the normal non-combustion of the heater
Fully open the side valve and fully close the heater side valve,
Flow rate through the bypass pipe and through the heater
If the sum of the flow rate and the flow rate is above a certain level, open the heater side valve.
And the flow rate passing through the heater is above a certain working flow rate.
In the case of hot water heaters that burn the heater in some cases
To detect the open or closed state of the bypass valve.
Detection means and the bypass side valve when the combustion of the heater is stopped
Even though the full open command was output to the
Is detected by the detection means that has not reached a certain degree or more.
If it is detected that the heater is not burning,
With a controller that makes the side valve fully open,
It is characterized by comprising.

[0008]

[Function] Under normal conditions, the valve on the bypass side is fully open and the valve on the heater side is fully closed during non-combustion, and when the calan is opened, water flows into the bypass pipe, and the bypass flow rate and the can body flow rate (this When the sum of the can body flow rate is 0) exceeds a certain flow rate, the heater side valve opens, and when the can body flow rate flowing to the heater side exceeds a certain working flow rate, the heater burns. To do.

[0009] In contrast, if the bypass-side valve fails in a state where no open fully closed position or fully, i.e., pressurized
When the bypass valve is not fully opened even if the bypass valve is fully opened when the combustion of the heater is stopped , the heater valve is set to the fully open state. It For this reason, when the calan etc. is opened, water flows to the side of the can body that is held in the open state, and when the sum of the bypass flow rate and the can body flow rate exceeds a certain flow rate and the can body flow rate exceeds a certain operating flow rate. The heater burns to supply hot water.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic configuration diagram of a water heater A according to an embodiment of the present invention. The heater 1 has a gas burner 3 inside the can body 2.
And the heat exchanger 4 are housed therein, and the gas burner 3 heats the water passing through the heat exchanger 4. Further, the combustion force of the gas burner 3 is controlled by the proportional control valve 5.

A water inlet pipe 6 connected to city water or the like is connected to the water inlet side of the heat exchanger 4, and a hot water outlet pipe 7 connected to a pipe terminal device such as a curran or a shower is connected to the hot water outlet side of the heat exchanger 4. Has been done. Further, a bypass pipe 8 is arranged between the water inlet pipe 6 and the hot water outlet pipe 7 so as to bypass the heat exchanger 4,
The bypass pipe 8 is provided with a bypass flow rate sensor 9 for detecting a flow rate (bypass flow rate) flowing through the bypass pipe 8 and a bypass servo valve (bypass side valve) 10. The bypass servo valve 10 adjusts the bypass flow rate to change the mixing ratio of the hot water heated by the heater 1 and the water flowing in the bypass pipe 8 to generate the hot water temperature (mixing temperature) discharged from the hot water pipe 7. In addition to controlling Tm, a fully open state is also possible, and the fully open state is maintained in the non-combustion state of the heater 1. A limit switch (hereinafter referred to as an open limiter) 17 for detecting the valve opening degree of the bypass servo valve 10 is attached to the bypass servo valve 10.

On the downstream side of the branch of the water inlet pipe 6 from the bypass pipe 8, a can body flow rate sensor 11 for detecting the water flow rate (can body flow rate) Qh of the heat exchanger 4 and a water inlet for detecting the water inlet temperature Tc. A temperature sensor 12 is provided.

Further, a hot water temperature sensor 13 for detecting the hot water discharge temperature Th of the hot water heated by the heat exchanger 4 and a can body servo valve (heater) are provided upstream of the confluence of the hot water discharge pipe 7 with the bypass pipe 8. A side valve) 14 is provided. This can body servo valve 14
Limits the can flow rate Qh so that the hot water supply does not exceed the capacity of the heater 1 and hot water below the set temperature soil Ts is discharged, and the fully closed state is also possible. Sometimes it is kept fully closed.

Further, the mixing temperature for detecting the mixing temperature Tm between the hot water heated by the heat exchanger 4 and the water passing through the bypass pipe 8 is provided downstream of the confluence point of the hot water outlet pipe 7 with the bypass pipe 8. A sensor 15 is provided.

The water heater A is controlled by a controller 16 having a microcomputer built therein. That is, the controller 16 includes the incoming water temperature sensor 12, the hot water temperature sensor 13, the mixing temperature sensor 15, the can body flow rate sensor 11, the bypass flow rate sensor 9, and the open limiter 17.
The detection signals of the bypass servo valve 1 are input based on these detection signals.
0, the can body servo valve 14, and the proportional control valve 5 are controlled.

FIG. 2 is a flow chart showing a control procedure for starting or stopping hot water discharge of the functions of the controller 16. In this water heater A, when the operation switch is turned off (NO in S21), the can body servo valve 14 is fully closed, and the bypass servo valve 1
The operation is stopped in the state where 0 is fully opened (S22), and cold water is prevented from flowing to the heat exchanger 4.

Therefore, even when the operation switch is turned on (YES in S21), the can body servo valve 1 is initially operated.
4 is completely closed, and the bypass servo valve 10 is fully open.

Next, the total flow rate (Qc + Qh) of the can flow rate Qh detected by the can flow rate sensor 11 and the bypass flow rate Qc detected by the bypass flow rate sensor 9 is the total flow rate MOQ (MOQ = minimum operating flow rate). ) It is determined whether to turn on or off (S
23). The determination of the total flow rate MOQ referred to here is, for example, Qc + Qh ≧ 4.0 liter / minute → total flow rate MOQ on Qc + Qh <3.2 liter / minute → total flow rate MOQ off. When the total flow rate (Qc + Qh) is equal to or less than a certain flow rate and it is determined that the total flow rate MOQ is off, a timer described later counts up (S2
From 4), the water heater enters the standby state with the total flow rate MOQ off (S23-24).

Now, when the scallop or the like at the end of the hot water outlet pipe 7 is opened, the bypass servo valve 10 is fully opened, so that water flows through the bypass pipe 8 and a sufficient total flow rate (Qc + Q) is reached.
h) [However, Qh = 0 in the current state of thinking] flows and the total flow rate MOQ is turned on, the can body servo valve 1
4 is opened (S25).

When the can body servo valve 14 is opened, water flows to the heat exchanger 4, so that the can body flow rate sensor 11 detects the can body flow rate Qh and determines whether the can body flow rate MOQ is ON or OFF ( S26). Here, the determination of the can body flow rate MOQ is, for example, Qh ≧ 2.0 liter / minute → can body flow rate MOQ on Qh <1.6 liter / minute → can body flow rate MOQ off.

If the total flow rate MOQ is on, the can body flow rate MOQ is normally turned on.
It is judged to be on and the timer is set to t = 0 (S27).
After that, the gas burner 3 is ignited and a normal hot water supply operation is performed (S28). For example, the can body flow rate Qh detected by the can body flow rate sensor 11, the incoming water temperature Tc detected by the incoming water temperature sensor 12, and the bypass flow rate sensor 9
Based on the bypass flow rate Qc detected by, the necessary heat amount for tapping hot water from the heat exchanger 4 to be hot water of the set temperature Ts after being mixed with water that has passed through the bypass pipe 8 is calculated. Then, the proportional control valve 5 is feedforward-controlled so that the heat supply amount in the heat exchanger 4 becomes equal to the calculated heat amount. Further, according to the deviation between the mixing temperature Tm detected by the mixing temperature sensor 15 and the set temperature Ts, the bypass servo valve 10 is feedback-controlled in a direction to reduce the deviation. further,
If the mixing temperature Tm does not reach the set temperature Ts even if the combustion capacity of the heater 1 is maximized, a large flow rate of water that exceeds the combustion capacity of the heater 1 flows to narrow the can body servo valve 14. The flow rate Qh is limited (overflow prevention), and hot water of the set temperature Ts is supplied.

During hot water supply, S21, S23, S2
Although steps 5 to 28 are repeated, the total flow rate MOQ is turned off (S23) when the calan or the like is closed, but at this time, the timer is not counting up (S24) and the routine jumps to step 26, Whether the can body flow rate MOQ is on or off is determined. At this time, since the can body flow rate MOQ is also turned off, the controller 16 outputs a fully open command to the bypass servo valve 10 (S29).

When a full open command is output to the bypass servo valve 10, the opening limiter 17 determines the valve opening degree of the bypass servo valve 10 to a constant opening degree (for example, several percent to several tens percent of the valve opening degree when fully opened). Is detected (S30), and it is confirmed that the bypass servo valve 10 is opened over a certain opening and is normal within the count-up time T (for example, 10 seconds; S32) of the timer. Then,
The can body servo valve 14 is fully closed (S31), and waits for the currant and the like to be opened again.

On the other hand, even if the curran or the like is closed and the fully open command (S29) for the bypass servo valve 10 is output, even if the count-up time T elapses and the timer counts up, the bypass servo valve 10 When 10 does not open beyond a certain opening (S30, S32), an error of the bypass servo valve 10 is displayed (S33), and the can body servo valve 14 is fully opened (S34).

In this way, when the bypass servo valve 10 is fully closed due to a failure, for example, the can body servo valve 14 is fully opened. Immediately, water flows into the heat exchanger 4.
The total flow rate MOQ is turned on (S23) by the volume Qh of the can bodies flowing through the heat exchanger 4, and the can body flow rate MO is further increased.
When Q is turned on (S26), normal combustion operation can be performed (S28). Therefore, according to this hot water supply device, even if the bypass servo valve 10 fails and is fully closed, hot water supply cannot be disabled and hot water can be supplied even in an unrepaired state. However, in this case, since the hot water supply temperature control (S28) cannot be performed by the bypass servo valve, the hot water supply temperature is adjusted only by the gas burner 3. That is, the control method of the gas burner 3 is switched to the feedback control, and the proportional control valve 5 is feedback-controlled in the direction to reduce the deviation between the mixing temperature Tm detected by the mixing temperature sensor 15 and the set temperature Ts.

In the above-mentioned embodiment , the servo valve whose flow rate is adjustable is used as the heater side valve and the bypass side valve.
The flow rate adjusting valve for preventing overflow and the can side valve may be separate, and the heater side valve and the bypass side valve may be open / close valves.

[0027]

According to the hot water supply apparatus of the present invention, when the opening degree of the bypass side valve does not reach the predetermined opening degree or more even though the bypass side valve full opening command is output, the heating is performed. Since the valve on the vessel side is fully opened, water immediately flows to the heater side when the calan, etc. is opened, and the sum of the bypass flow rate and the can body flow rate becomes a certain flow rate or more, and the can body flow rate becomes a certain working flow rate or more. When it becomes hot, the heater burns and hot water is discharged.
Therefore, even if the bypass side valve fails in the fully closed position, the hot water supply device is not disabled and hot water can be discharged.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a hot water supply device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a control procedure for starting or stopping hot water discharge in the embodiment.

FIG. 3 is a schematic configuration diagram of a hot water supply device according to a conventional example.

[Explanation of symbols]

 1 Heater 6 Inlet pipe 7 Hot water pipe 8 Bypass pipe 9 Bypass flow sensor 10 Bypass servo valve 11 Can body flow sensor 14 Can body servo valve 16 Controller 17 Open limiter

Claims (1)

[Claims] 1. A water inlet pipe and a hot water outlet pipe are connected to a water inlet side and a hot water outlet side of a heater, respectively, and a bypass pipe is connected between the water inlet pipe and the hot water outlet pipe so as to bypass the heater, and the bypass pipe is connected to the bypass pipe. A bypass valve is installed, and a heater valve is installed between the downstream side of the branch point of the water inlet pipe and the bypass pipe and the upstream side of the confluence point of the hot water outlet pipe with the normal side of the heater. When the bypass side valve is fully opened during combustion
Both fully close the heater side valve, and connect the bypass pipe.
The sum of the flow rate passing through and the flow rate passing through the heater is constant
When the flow rate is higher than the above, the heater side valve is opened and the heater
If the flow rate passing through the
For detecting the open or closed state of the bypass side valve in a hot water heater
Outputs a full-open command to the bypass valve when the detection means and the combustion of the heater are stopped
Despite the above, the opening of the bypass side valve is above a certain opening
If the detection means detects that it has not reached
Keeps the heater side valve open even when the heater is not burning.
A hot water supply device including a controller that is held .