JP3650675B2 - Water heater - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water heater, and more particularly to a water heater having a function of preventing freezing of a water circuit.
[0002]
[Prior art]
FIG. 5 illustrates a schematic configuration of a water circuit and a gas circuit of a water heater.
A water valve (10) is provided upstream of the water circuit (1), and a water pressure responsive part (21) and a heat exchanger (31) of the water pressure responsive gas valve (2) are provided downstream of the water valve (10). Arranged in order.
[0003]
The gas circuit (33) to the gas burner (32) constituting the water heating unit (3) together with the heat exchanger (31) includes a main valve (34) and the water pressure responsive gas valve ( An output valve (22), which is a component of 2), is disposed, and the output valve (22) opens and closes in conjunction with the water pressure responsive portion (21). The state of the water pressure responsive part (21) is monitored by a limit switch (24), and the limit switch (24) and the water pressure responsive part (21) constitute a water flow switch (25).
[0004]
FIG. 6 shows a specific configuration of the water pressure responsive gas valve (2) and the water flow switch (25).
An output shaft (211) is connected to the diaphragm (210) of the water pressure responsive portion (21) that is deformed by the water pressure change in the water circuit (1), and the output shaft (211) is interlocked with the forward / backward movement. While the output valve (22) in the gas circuit (33) is opened and closed, the limit switch (24) is pushed by the projecting body (212) provided on the output shaft (211), and this is turned ON / OFF It has become.
[0005]
The output of the limit switch (24) is applied to the control device (5) .The control device (5) further includes an ignition device (35) for the gas burner (32), an operation switch (51), and the like. Electrical connection.
In this case, when the operation switch (51) is turned ON, the water valve (10) of the water circuit (1) is opened. When the water valve (10) is opened by opening the water valve (10), the water pressure responsive part (21) of the water pressure responsive gas valve (2) is activated by the water pressure fluctuation at this time, and the output shaft (211 ) Advances, and this opens the output valve (22). On the other hand, when the output shaft (211) moves forward as described above by the operation of the hydraulic pressure response portion (21), the limit switch (24) is moved by the projecting body (212) protruding to the side of the output shaft (211). When pressed, a water flow detection signal is output from the switch. Then, based on the water flow detection signal, the ignition device (35) is actuated and the main valve connected to the gas burner (32) is opened, and the gas burner (32) is ignited and maintained in the combustion state. Thus, the hot water supply operation proceeds.
[0006]
[Problems to be solved by the invention]
However, in this kind of water heater, when the inside of the water circuit (1) freezes on a cold winter night or the like, the accumulated water in the water pipe constituting the water circuit (1) expands in volume, and the water pipe Worry about breakage. Further, when the water staying in the primary water chamber (219) of the water pressure responsive part (21) of the water pressure responsive gas valve (2) expands due to freezing, the diaphragm (210) Is deformed and the limit switch (24) is maintained in the on state (pseudo-detection state of water flow). If the operation switch (51) is turned on in this state, water will enter the water circuit (1). There is an inconvenience that the gas burner (32) starts to burn although it does not flow.
[0007]
This application was made in view of such points,
`` A water circuit (1) that becomes water-permeable by opening the water valve (10),
A water heater comprising a water heating section (3) for heating water flowing in the water circuit (1), wherein a water passage pipe constituting the water circuit (1) is broken or a water heating section (3 The problem is to prevent freezing of the water circuit (1) during cold winter nights.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the invention of claim 1
`` Freezing danger state detection means (27) for outputting a freezing danger signal when the water circuit (1) is in a freezing danger state;
It is provided with valve control means (28) for opening the water valve (10) based on the freezing danger signal ”.
[0009]
According to the above means, when the inside of the water circuit (1) is about to freeze, a freezing danger signal is outputted from the freezing danger state detecting means (27), and the water valve (10) is opened by the freezing danger signal and the communication is made. The inside of the water circuit (1) is maintained in the water state, thereby preventing freezing in the water circuit (1).
The invention of claim 2
`` The valve control means (28) is to maintain the water valve (10) open for a set time,
There is further provided a water heating unit control means (29) for operating the water heating unit (3) when the water valve (10) is open ''. The temperature in the water circuit (1) near and downstream of the water heating section (3) can be brought to a high temperature state by the generated heat.
[0010]
The invention of claim 3
“The freezing danger state detecting means (27) includes a diaphragm (210) stretched so as to be a part of a wall of the water circuit (1), and stagnant water in the water circuit (1). When the diaphragm (210) is deformed due to an increase in pressure in the water circuit (1) at the start of the operation, a switch unit that is turned on to output the freezing danger signal in conjunction with the diaphragm (210) is provided. In this case, when the stagnant water in the water circuit (1) begins to freeze and expands in volume, the diaphragm (210) deforms due to an increase in pressure in the water circuit (1) due to the volume expansion, and the In conjunction with the deformation, the switch section is turned ON and a freezing danger signal is output. Thus, according to the invention of claim 3, since the volume expansion of the stagnant water that occurs when the stagnant water in the water circuit (1) starts to freeze is detected, the water temperature in the water circuit (1) is controlled. Unlike the case of determining the freezing danger state based on this, the freezing danger state can be directly detected.
[0011]
【The invention's effect】
As described above, according to the first aspect of the present invention, the water circuit (1) can be prevented from freezing in the cold night of winter. Can be prevented. Further, since the inside of the water circuit (1) does not freeze, it is possible to avoid an abnormal state in which the water heating section (3) generates heat while the inside of the water circuit (1) is frozen and water does not flow.
[0012]
According to the second aspect of the present invention, the water flowing in the water circuit (1) is heated and heated during the freeze prevention operation, so that the freezing can be prevented more reliably.
According to the third aspect of the present invention, the freezing danger state is determined by detecting the volume expansion of the staying water in the water circuit (1) at the beginning of freezing. Therefore, the freezing danger state is determined based on the water temperature of the staying water. Compared with the case where it does, this dangerous state can be detected directly and reliably, and, thereby, a highly accurate control operation can be performed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic diagram of a water circuit, a gas circuit, and a control circuit of a water heater according to an embodiment of the present invention.
A motor-driven water valve (10) is disposed at the upstream end of the water circuit (1), and a water pressure responsive portion (21) of the water pressure responsive gas valve (2) is disposed downstream thereof. The output valve (22) constituting the water pressure responsive gas valve (2) is disposed on the downstream side of the main valve (34) in the gas circuit (33). The interlocking mechanism of the water pressure responsive portion (21) and the output valve (22) is configured in the same manner as that of FIG. 6 described above, but in the water heater of the present embodiment, as shown in FIG. In addition, two first and second limit switches (240) and (241) are turned on and off by a projecting body (212) of an output shaft (211) connected to the diaphragm (210). . In this case, when the stagnant water in the primary water chamber (219) of the water pressure responder (21) starts volume expansion due to freezing, the diaphragm (210) is slightly deformed and the output shaft (211) moves to the left of the figure. Extruded slightly. Specifically, when the vicinity of the primary water chamber (219) starts to freeze, the force pushing the output shaft (211) to the outside against the end surface (211a) of the output shaft (211) resists a spring (not shown). When the acting force pushing out exceeds the spring force, the output shaft (211) is pushed out in the direction. Then, the first limit switch (240) is turned on to output a freezing danger signal. On the other hand, when the water circuit (1) enters a water flow state and a water flow is generated and the diaphragm (210) is greatly deformed, the second limit switch (241) is turned on to output a water flow detection signal. Therefore, in this embodiment, the assembly of the first limit switch (240) and the hydraulic pressure response portion (21) corresponds to the freezing danger state detection means (27) described as the above-mentioned invention specific matter, and The first limit switch (240) corresponds to the switch portion described as the invention specific matter of the invention of claim 3. The second limit switch (241) and the water pressure responsive part (21) constitute a water flow switch (25).
[0014]
On the downstream side of the water pressure responsive gas valve (2) in the water circuit (1), there is a water amount adjustment unit (261) that constitutes a capacity adjustment cock (26) for adjusting the heat generation capacity of the gas burner (32). A gas amount adjusting unit (262) that is provided and interlocked with the water amount adjusting unit (261) is inserted in the vicinity of the gas burner (32) in the gas circuit (33). Then, when the operation handle (263) of the capacity adjustment cock (26) is turned, the water amount adjustment unit (261) is maintained in the fully open state, and the gas amount adjustment unit (262) is moved from the minimum opening to the maximum opening. When the operation handle (263) is further rotated, the water amount adjusting unit (261) changes from the maximum opening to the minimum opening while the gas amount adjusting unit (262) is maintained at the maximum opening. Thus, the hot water supply capacity can be adjusted.
[0015]
In the water circuit (1), on the downstream side of the capacity adjustment cock (26), a heat exchanger (31) constituting the water heating unit (3) and a shower head (37) on the downstream side thereof are provided. .
Electrical components such as the main valve (34) are electrically connected to a control device (5) incorporating a microcomputer, and the control device (5) is disposed in the vicinity of the gas burner (32). An ignition device (35) and a flame detector (39) are electrically connected.
[0016]
The control device (5) is driven by a battery (61), and a circuit connected from the battery (61) to the power supply terminal (52) of the control device (5) has a switching transistor (62). Has been inserted.
The output of the automatic return type push button type operation switch (51) is applied to the base of the switching transistor (62) via a capacitor (55) and an inverting circuit (58), and the operation switch (51) The signal of the output part is directly applied to the control device (5). A discharging diode (57) is inserted between the circuit portion between the capacitor (55) and the inverting circuit and the ground portion. The output of the self-holding output terminal (53) in the control device (5) is applied to the switching transistor (62).
[0017]
The output of the output contact (240a) of the first limit switch (240), which is turned ON / OFF in conjunction with the water pressure responsive part (21) of the water pressure responsive gas valve (2), is switched via an inverting circuit (59). Applied to the base of (62). The output of the output contact (240a) is directly applied to the control device (5), and on the other hand, the ON / OFF operation is performed in conjunction with the water pressure responsive part (21) of the water pressure responsive gas valve (2). The output of the output contact (241a) of the second limit switch (241) is also applied to the control device (5).
[0018]
A control program having the contents shown in the flowchart of FIG. 3 is stored in the microcomputer incorporated in the control device (5). Hereinafter, the actual operation of the water heater will be described with reference to FIGS.
When the operation switch (51) is turned on (the circuit connected to the operation switch (51) is connected to the circuit on the battery (61) side), the capacitor (55) is charged and its inverted signal is inverted to the inversion circuit (58 As a result, the switching transistor 62 is turned on for a certain time (a time corresponding to a time constant determined by the capacitance of the capacitor 55 and the resistance value of the resistor in the inverting circuit 58). Thereby, the microcomputer in the control device (5) starts the control operation according to the flowchart shown in FIG. On the other hand, even when the operation switch (51) is not turned ON, the water pressure responsive part (21) of the water pressure responsive gas valve (2) arranged in the water circuit (1) starts to freeze. And the microcomputer in the control device (5) is started. That is, when the accumulated water in the primary water chamber (219) of the water pressure responding section (21) starts to freeze and expands in volume, the output shaft (211) moves forward and protrudes due to the deformation of the diaphragm (210). The body (212) turns on the first limit switch (240). Then, the output contact (240a) of the first limit switch (240) is connected to the power supply side, and the inverted signal is applied from the inverting circuit (59) to the switching transistor (62), thereby the control device (5) The microcomputer starts.
[0019]
When the microcomputer in the control device (5) is started as described above and the control operation according to the flowchart of FIG. 3 is started, first, in step (ST1) (ST2), the operation switch (51) and The output of the first limit switch (240) is examined. That is, the state of the operation switch monitoring terminal (65) and the freeze monitoring terminal (66) to which the output of the output contact (240a) portion of the operation switch (51) and the first limit switch (240) is applied is examined, and the freeze monitoring terminal When the H signal, which is a freezing danger signal, is applied only to (66) (the water pressure responsive part (21) of the water pressure responsive gas valve (2) begins to freeze and the first limit switch (240) is turned on) In the case), the freeze prevention process of step (ST3) to step (ST10) is executed.
[0020]
In step (ST3), the L signal is output from the self-holding output terminal (53) and the switching transistor (62) is maintained in the ON state, whereby power is supplied to the microphone computer of the control device (5). Maintained.
Next, in step (ST4), the water valve (10) is opened. The function unit in the microcomputer that executes the control for opening the water valve (10) corresponds to the invention specific matter of the invention of claim 1 described above. Next, step (ST5) is executed, and the output of the second limit switch (241) is examined in order to confirm whether or not the water circuit (1) is in a water flow state. That is, when the water flows into the water circuit (1), the output shaft (211) connected to the water pressure responsive portion (21) of the water pressure responsive gas valve (2) greatly moves forward and moves to the second limit switch (241). It is judged whether or not is pushed by the projecting body (212) and turned on. When the output shaft (211) moves greatly, the output valve (22) is opened in conjunction with the output shaft (211). When the second limit switch (241) is turned on, the output contact (241a) is connected to the power source side and the H signal is applied to the water flow monitoring terminal (67). In ST6), the gas burner (32) of the water heating section (3) is burned. That is, the main valve (34) is opened and the ignition device (35) is operated, whereby the gas burner (32) is ignited and maintained in the combustion state, and the hot water flows out from the shower head (37). In this embodiment, the functional unit of the microcomputer that executes the step (ST6) to burn the gas burner (32) is the water heating unit control means (29) described as the invention specific matter of the invention of claim 2. It corresponds to. Then, this hot water discharge operation is continued for 10 minutes (see step (ST7)). Then, the temperature of the water circuit (1) on the downstream side of the heat exchanger (31) is increased, and the water pressure responsive part in the vicinity of the upstream side of the heat exchanger (31) is transmitted by the heat transferred from the heat exchanger (31). The temperature in (21) also rises, so that freezing of the entire water circuit (1) can be avoided. In the present embodiment, the gas burner (32) is combusted, but the water valve (10) may be kept open while the gas burner (32) is extinguished. This is because even in such a case, the flow of water occurs in the water circuit (1) and the freezing thereof can be avoided. In this embodiment, in order to avoid freezing, the water valve (10) is fully opened in the same way as in normal use, but a minimum amount of water that does not freeze is present in the water circuit (1). You may make it control the opening degree of the said water valve (10) so that it may flow. At this time, the gas burner (32) may be extinguished, but it is desirable to control the amount of gas supplied to the gas burner (32) so that the amount of combustion corresponds to the amount of water.
[0021]
Next, the gas burner (32) is extinguished by closing the main valve (34) (see step (ST8)), and then the water valve (10) is closed in step (ST9) and step (ST10) Thus, the self-holding output terminal (53) is set to the H state to deactivate the switching transistor (62). Then, the power supply to the microcomputer of the control device (5) is stopped, and the freeze prevention operation is completed.
[0022]
Next, a case where a hot water operation is performed with the operation switch (51) will be described.
When the capacitor (55) is in a charged state immediately after the operation switch (51) is operated, the H signal is applied to the operation switch monitoring terminal (65) for a while. Accordingly, when the operation switch monitoring terminal (65) is in the H state when step (ST1) is executed, it is determined that the operation switch (51) has been turned ON, and steps (ST11) to (ST16) are performed. Hot water supply control is performed.
[0023]
That is, in step (ST11) (ST12), the self-holding output terminal (53) is set to the L state, and then the water valve (10) is opened. In step (13), water enters the water circuit (1). If it is confirmed that the gas has flowed, the gas burner (32) is burned in step (ST14). Then, when step (ST15) is executed and the hot water stop operation is performed by turning on the operation switch (51) again, in step (ST16), the gas burner (32) is extinguished and the water valve (10) is closed, Further, an H signal is output to the self-holding output terminal (53) to return the switching transistor (62) to the OFF state.
[0024]
If it is determined that neither the operation switch (51) nor the first limit switch (240) is in the ON state when step (ST1) (ST2) is executed, the control operation is immediately terminated. Return to the initial state. When the operation switch (51) and the first limit switch (240) are turned on again in this state, the microcomputer of the control device (5) is re-energized and the control of FIG. Resumed.
[0025]
In the above embodiment, the first limit switch (240) and the second limit switch (241) can be used to determine the amount of advance movement of the output shaft (211) connected to the diaphragm (210). However, as shown in FIG. 4, a potentiometer (7) for detecting the amount of movement of the output shaft (211) connected to the water pressure responsive part (21) of the water pressure responsive gas valve (2) may be used. .
[0026]
In the above embodiment, the first limit switch (240) for detecting the volume expansion when the accumulated water in the water pressure responsive part (21) of the water pressure responsive gas valve (2) starts to freeze is provided. A thermistor that detects the temperature of the staying water near the water pressure actuator (21) or the outside air temperature is provided, and the output when the thermistor detects a freezing danger temperature (for example, 1 ° C or less) is used as a freezing danger signal. When the danger signal is generated, the above-described freeze prevention operation may be executed. Further, a strain gauge is disposed in the pipe constituting the water circuit (1), and the freezing is performed by utilizing the change in the output of the strain gauge that occurs as the pressure increases in the water circuit (1) that occurs in the initial stage of freezing. An initial state may be detected.
[0027]
In the above embodiment, the combination of the gas burner (32) and the heat exchanger (31) heated by the gas burner (32) is adopted as the water heating section (3), but the water flow in the water circuit (1) is heated. You may comprise a water heating part using an electric heater.
[Brief description of the drawings]
FIG. 1 is a schematic structural view of a water heater according to an embodiment of the present invention. FIG. 2 is a detailed view of the vicinity of a water pressure responsive gas valve (2) shown in FIG. FIG. 4 is a flowchart for explaining a control program stored in a microcomputer incorporated in the control device (5) of the device. FIG. 4 is an explanatory diagram of a modified example of the first limit switch (240) and the second limit switch (241). ] Schematic structure diagram of a conventional water heater [FIG. 6] Detailed view of the water pressure responsive gas valve (2) used in the water heater of FIG.
(1) ... Water circuit
(3) ・ ・ ・ Water heating unit
(10) ... Water valve
(27) ... Freezing danger state detection means
(28) ... Valve control means
(29) ... Water heating part control means
(210) ・ ・ ・ Diaphragm

Claims (3)

A water circuit (1) that enters a water flow state by opening the water valve (10);
A water heater comprising a water heating section (3) for heating water flowing in the water circuit (1),
A freezing danger state detection means (27) for outputting a freezing danger signal when the water circuit (1) is in a freezing danger state, and
A water heater provided with valve control means (28) for opening the water valve (10) based on the freeze danger signal. The valve control means (28) is for maintaining the water valve (10) in a valve open state for a set time,
The water heater according to claim 1, further comprising water heating unit control means (29) for operating the water heating unit (3) when the water valve (10) is opened. The freezing danger state detecting means (27) includes a diaphragm (210) stretched so as to become a part of a constituent wall of the water circuit (1), and stagnant water in the water circuit (1). And a switch portion that is turned on to output the freezing danger signal in conjunction with the deformation of the diaphragm (210) due to a pressure increase in the water circuit (1) at the beginning. The water heater according to claim 1 or 2.

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