JP2003042553A - Water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water heater in which occurrence of an undershoot is reduced at a hot water re-outputting time after a small quantity of hot water is supplied (so-called a 'tricked water') and a maximum usable flow rate is not limited. SOLUTION: The water heater comprises a water input passage 10 and a hot water output passage 19 to a hot water storage tank 2, a bypass passage 17 branched from the input passage 10 and connected to the output passage 19, a mixing means 18 for mixing the water from the passage 10 with the warm water from the passage 19 at a connector of the passage 19 to the passage 17, a remote controller for setting a temperature of the hot water output from the means 18, and a flow detecting means 8 for detecting a flow rate of the hot water output from the means 18. The heater further comprises a first check valve 20 at the passage 17, and a second check valve 21 at a downstream side from a branch unit of the passage 10 to the passage 17 in such a manner that a valve opening pressure of the second valve 21 is larger than that of the first valve 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water inlet passage and a hot water outlet passage for heat exchange means, a bypass passage branched from the water inlet passage and connected to the hot water outlet passage, and a connecting portion between the hot water outlet passage and the bypass passage. In addition, the present invention relates to a hot water supply device comprising mixing means for mixing water from the water inlet passage and hot water from the hot water outlet passage.

[0002]

2. Description of the Related Art A conventional hot water supply apparatus having a hot water storage tank and a mixing means will be described in detail with reference to FIG. As shown in the drawing, the hot water supply device includes a combustion can body 1, an inlet 10 through which water enters from a water supply source (not shown) to a hot water storage tank 2 which is a heat exchange means provided in the combustion can body 1, and heating. The hot water in the hot water storage tank 2 heated by the burner 13, which is a means, is provided with a hot water discharge passage 19 through which hot water flows out. Also, the hot water storage tank 2
Is provided with a hot water storage temperature sensor 9 for detecting a hot water temperature Tk in the hot water storage tank 2 as well as a heat exchange temperature detecting means. Furthermore, the bypass passage 17 that is branched from the water inlet passage 10 and is connected to the hot water outlet passage 19 without the hot water storage tank 2 and the high temperature hot water in the hot water storage tank 2 at the confluence of the bypass passage 17 and the hot water outlet passage 19. A mixing valve 18 for mixing and controlling water sent from the bypass 17 by a stepping motor M is provided. At the outlet of the mixing valve 18, there is a mixing passage 11 through which mixed hot water comes out, which is connected to a hot water tap (not shown).

In addition, the water inlet 10 has a water temperature sensor 14 for detecting the temperature Tc of water from a water supply source, and a quantity Q of water.
The outlet temperature Th of the hot water storage tank 2 is provided in the hot water discharge passage 19 on the upstream side (hot water storage tank 2 side) of the water amount sensor 8 for detecting the temperature and the mixing valve 18.
In the mixing passage 11 on the downstream side of the hot water tank outlet temperature sensor 15 and the mixing valve 18 for detecting the mixed hot water temperature T after mixing.
A mixed hot water temperature detection sensor 16 for detecting m is provided.

The burner 13 includes a fan 3 for supplying air required for combustion, a nozzle 5 for supplying kerosene to form a flame, a spark plug 6 required for ignition,
It is composed of CdS7 or the like that detects the presence or absence of a flame. Further, a kerosene supply pipe 12 for supplying kerosene to the nozzle 5 provided in the burner 13 is provided, and the kerosene supply pipe 12 is provided with an electromagnetic pump 4 for pumping kerosene to the nozzle 5.

The bypass pipe 17 is provided with a check valve 2 for preventing hot hot water in the hot water storage tank 2 from flowing back to the water side.
0 is provided.

The water heater further includes the sensors 14 and
Detection signals (Tc, Q, Th,
Tm, Tk) and a control unit (not shown) that controls the electromagnetic pump 4, the burner 13, the mixing valve 18, etc. based on a set temperature signal (Ts) from a hot water supply temperature setting switch provided on a remote controller (not shown). Also equipped with.

The conventional hot water supply operation will be described based on the above configuration. Now, when the operation switch of the hot water supply device is turned on by the remote controller (not shown), the hot water storage tank 2 is kept at a predetermined high temperature Tks (for example, 80 ° C.) even when hot water is not actually used by a faucet or the like. In order to keep the internal warm water temperature, the burner 13 is repeatedly turned on and off with the maximum combustion capacity.

When the use of hot water is actually started, the water from the water supply source flows from the water inlet 10, the water amount sensor 8, the hot water tank 2, and the hot water outlet 19 into the hot water and the water inlet. The water that flows in through the path of the bypass pipe 17 that branches,
It is mixed by the mixing valve 18 and comes out from the mixing passage 11.

The control unit (not shown) controls the water temperature Tc detected by the water temperature sensor 14 in the water channel 10 and the hot water channel 1.
9. Hot water outlet temperature Th detected by hot water tank outlet temperature sensor 15
And the set hot water supply temperature Ts set by the user by the remote controller, the mixing ratio of the water flowing through the bypass passage 17 and the hot water flowing through the hot water discharge passage 19 is set as follows so that the hot water after hot water mixing reaches the set hot water supply temperature. The control signal is output to the mixing valve 18 so that the calculated mixing ratio can be calculated by the calculation formula (1). When using hot water: Mixing ratio = (Ts-Tc) / (Th-Tc) (1) When hot water supply is stopped: Mixing ratio = (Ts-Tc) / (Tks-Tc) (2) The water amount sensor 8 is used to judge when hot water is used and when hot water is stopped.
The detected water flow rate Q is detected. That is, when the detected incoming water flow rate Q is detected, it is determined that the hot water supply is in use, and when the detected incoming water flow rate Q is not detected, it is determined that the hot water supply is stopped.

As a result, the hot water from the hot water outlet 19 and the water from the bypass 17 are mixed at an appropriate mixing ratio to become hot water having the set hot water supply temperature Ts set by the remote controller.
It flows into the mixing path 11. During this time, the burner 13 keeps the hot water tank 2
A combustion operation is performed to maintain the hot water therein at a predetermined high temperature Tks (for example, 80 ° C.).

By the way, normally, the mixing valve 18 is controlled by the calculation result of the above (1) on condition that the water flow rate sensor 8 detects the water flow rate. However, it is necessary to detect the water flow rate due to the detection capability of the water flow rate sensor 8. When a small amount of hot water cannot be supplied,
The mixing valve 18 is stopped at the position of the mixing ratio calculated by the arithmetic expression (2). At this position, when supplying a small amount of hot water, due to the relationship with the first check valve 20 and the like, the high temperature hot water on the side of the hot water storage tank 2 with a large pressure loss on the water side and a small pressure loss is mixed in the mixing passage 11
There is a fear that it will come out more.

In order to solve this, the hot water temperature Tm detected by the hot water mixing sensor 16 is monitored and the hot water mixing valve 18 is operated.
Was being controlled. When the detected hot water temperature Tm becomes equal to or higher than a predetermined temperature, the mixing valve 18 is moved to the water side (bypass pipe 1
It was controlled to the fully open position on the 7 side), that is, the fully closed position on the hot water side (the tap pipe 19 side). Alternatively, instead of controlling the mixing valve 18 by the detected hot water temperature Tm, a pressure loss generating means such as an orifice is provided in the hot water discharge pipe 19 to facilitate the flow on the water side and prevent hot water from being discharged.

[0013]

Therefore, in the conventional hot water supply apparatus, in the method of controlling the mixing valve 18 by monitoring the hot water discharge temperature Tm detected by the mixed hot water temperature detection sensor 16 at the time of supplying a small amount of hot water, the mixing valve 18 is a water heater. Since it is in a standby state at the side fully open position, if hot water starts to be used in this state, the hot water coming out of the hot water tap will flow until the mixing valve 18 moves to the distribution ratio position of the set temperature Ts of the remote controller. There is a problem that an undershoot phenomenon in which the temperature (detected temperature Tm of the mixed hot water temperature detection sensor 16) becomes lower than the set temperature Ts is large, which causes unpleasant feeling.

Further, in place of the method of controlling the mixing valve 18 by monitoring the hot water temperature Tm detected by the mixed hot water temperature detection sensor 16, a pressure loss generating means such as an orifice is provided in the hot water discharge passage 19 to facilitate the flow on the water side. In the method, there was a problem that the maximum usable flow rate was limited and decreased even during normal use (when an appropriate amount of hot water was discharged).

The present invention has been made to solve the above problems, and an object of the present invention is to provide a hot water supply apparatus in which undershoot is less likely to occur and the maximum usable flow rate is not limited when the hot water is again discharged after a small amount of hot water is supplied. To provide.

[0016]

In order to achieve the above object, the first aspect of the present invention is to detect the heat exchange means for heating the hot water inside and the hot water temperature in the heat exchange means. Heat exchange temperature detecting means, heating means for heating hot water in the heat exchanging means, water inlet passage and hot water outlet passage for the heat exchanging means, and bypass passage branched from the water inlet passage and connected to the hot water outlet passage. And mixing means for mixing water from the water inlet path and warm water from the hot water outlet path at a connection portion between the hot water outlet path and the bypass path, and setting the temperature of hot water discharged from the mixing means. Remote control,
A hot water supply apparatus comprising: a flow rate detecting means for detecting a flow rate of hot water discharged from the mixing means; and a first check valve in the bypass passage, which is downstream from a branch portion between the water inlet passage and the bypass passage. Since the second check valve is provided on the side and the valve opening pressure of the second check valve is set to be higher than the valve opening pressure of the first check valve, the hot water temperature Tm detected by the mixed hot water temperature detection sensor 16 is detected. Need not be monitored to control the mixing valve 18,
The mixing valve 18 remains stopped at the standby position when the hot water supply is stopped, so that when the hot water is again discharged after a small amount of hot water (so-called choro water), undershoot is less likely to occur and the maximum usable flow rate is not limited.

According to a second aspect of the present invention, when the opening pressure of the check valve is less than the flow rate detectable by the flow rate detecting means, the first check valve is opened and the second check valve is not opened. Above the flow rate detectable by the detection means, the first check valve and the second check valve
Since both of the check valves are set to open, pressure loss occurs due to the mounting of the check valve, but the maximum usable flow rate is not limited in normal hot water usage.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a configuration diagram of a hot water supply device according to an embodiment of the present invention. The same components as those in the conventional embodiment shown in FIG. 2 described above are designated by the same reference numerals and the description thereof will be omitted.

As shown in the figure, the hot water supply device is a bypass passage 1.
7 is provided with a first check valve 20, a second check valve 21 is provided downstream of the branch between the water inlet 10 and the bypass 17 (on the side of the hot water tank 2), and the second check valve 21 is provided. The opening pressure of the check valve 21 is set higher than the opening pressure of the first check valve 20. Further, the opening pressures of the check valves 20 and 21 are set so that the first check valve 20 opens and the second check valve 21 does not open when the flow rate is less than the flow rate detectable by the flow rate detection sensor 8. Therefore, both the first check valve 20 and the second check valve 21 are set to open when the flow rate can be detected by the flow rate detection sensor 8 or more.

Therefore, the first check valve 2 provided in the bypass passage 17 has a low water supply pressure when supplying a small amount of hot water which cannot detect the water flow rate due to the detection capacity of the water amount sensor.
Only the 0 is opened, and the second check valve 2 is provided on the downstream side (the hot water storage tank 2 side) of the branch portion between the water inlet passage 10 and the bypass passage 17.
Since No. 1 is not opened, only the water from the water inlet 10 via the bypass 17 passes through the mixing valve 18 as it is and is discharged from the faucet, so there is no concern that hot water will come out.

Then, when the amount of water flow detected by the water amount sensor 8 flows, both the first check valve 20 and the second check valve 21 open, so that the mixing valve 18 based on the above equation (1).
Is controlled. At this time, since the position of the mixing valve 18 is stopped at the standby position when the hot water supply is stopped, the undershoot at the time of re-hot water supply is suppressed.

Further, the valve opening pressure of the check valve is measured by the water amount sensor 8
If the flow rate is less than the detected flow rate of, the first check valve 20 opens,
Since the second check valve 21 is set not to open and both the first check valve 20 and the second check valve 21 are set to open above the flow rate detected by the water amount sensor 8, the check valve However, the maximum usable flow rate is not limited under normal hot water usage conditions.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram of a conventional hot water supply device.

[Explanation of symbols]

1 ... Combustion can 2 ... Hot water storage tank (heat exchange means) 3 ... fan 4 ... Electromagnetic pump 5 ... Nozzle 6 ... Spark plug 7 ... CdS 8 ... Water quantity sensor 9 ... Hot water storage temperature sensor (heat exchange temperature detection means) 10 ... Inlet 11 ... Mixing path 12 ... Kerosene supply pipe 13 ... Burner 14 ... Inlet temperature sensor 15 ... Hot water tank outlet temperature sensor 16. Mixed hot water temperature detection sensor 17 ... Bypass 18 ... Mixing valve 19 ... Dewaji 20 ... First check valve 21 ... Second check valve

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tetsuro Takada             43-1, Uozakihama-cho, Higashinada-ku, Kobe-shi, Hyogo             Inside this Yupro Co., Ltd. (72) Inventor Osamu Ishikura             43-1, Uozakihama-cho, Higashinada-ku, Kobe-shi, Hyogo             Inside this Yupro Co., Ltd. (72) Inventor Toshiharu Oe             43-1, Uozakihama-cho, Higashinada-ku, Kobe-shi, Hyogo             Inside this Yupro Co., Ltd.

Claims (2)

[Claims] 1. A heat exchange means for heating the hot water inside, a heat exchange temperature detecting means for detecting the temperature of the hot water in the heat exchange means, and a heating means for heating the hot water in the heat exchange means. An inlet and outlet for the heat exchange means,
A bypass passage branched from the water inlet passage and connected to the hot water outlet passage; and a mixing means for mixing water from the water inlet passage and hot water from the hot water outlet passage at a connection portion between the hot water outlet passage and the bypass passage. In the hot water supply device, which is provided with a remote controller for setting the temperature of the hot water discharged from the mixing means, and a flow rate detection means for detecting the flow rate of the hot water discharged from the mixing means, the first bypass path is provided. A check valve is provided, and a second check valve is provided on a downstream side of a branch portion between the water inlet path and the bypass path, and a valve opening pressure of the second check valve is adjusted to that of the first check valve. A hot water supply device characterized in that the pressure is higher than the valve opening pressure. 2. The hot water supply apparatus according to claim 1, wherein the first check valve opens and the second check valve opens when the opening pressure of the check valve is less than the detectable flow rate of the flow rate detecting means. Is set not to open, and both the first check valve and the second check valve are set to open when the flow rate is equal to or higher than the flow rate detectable by the flow rate detecting means.