JP2507244B2 - 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.

[0002]

2. Description of the Related Art For example, a water heater provided with a heat exchanger using a gas burner and a hot water supply passage passing through the heat exchanger is usually provided with a water governor, a water flow switch or the like at a midway point of the hot water supply passage. Detection means is provided, and when the water flow is detected by the water flow detection means, the water flow detection means is operated to supply and ignite gas to the gas burner to operate the heat exchanger.

[0003] In this type of water heater, when a malfunction of a water governor, a water flow switch, or the like occurs, the heat exchanger is used even when there is no water flow in the hot water supply path or when only a small amount of water is supplied. Operates, so-called residual fire may occur, and when such residual fire occurs, the water in the hot water supply path will be overheated.

For this reason, in this type of water heater, an overheating prevention device is provided in order to prevent the water in the hot water supply passage from being overheated. When the water becomes extremely hot, the operation of the heat exchanger is forcibly stopped.

Further, in this kind of water heater, since the upstream end of the hot water supply passage has a relatively low incoming water temperature, a resin pipe member made of vinyl chloride or the like is inexpensive and easy to handle. Some are connected to a water pipe or the like through.

However, in such a water heater,
When an afterglow occurs as described above, even if the operation of the heat exchanger is stopped, high-temperature hot water remains in the hot-water supply passage in the heat exchanger, and this high-temperature hot water is high pressure. Therefore, hot water in the hot water supply passage in the heat exchanger may suddenly flow backward in the hot water supply passage to the upstream side. When such a situation occurs, the hot water supply passage is connected to the water pipe or the like. There is a possibility that the resin piping member may be damaged by heat.

In order to prevent such inconvenience, a check valve is provided at a location between the heat exchanger of the hot water supply passage and the resin piping member, and the check valve is used to prevent the resin from the heat exchanger side. It is possible to prevent hot water from flowing back to the piping member side.

However, in this type of water heater, it is general that the hot water supply passage is drained from the upstream portion of the hot water supply passage through a drain pipe. If a check valve is provided, it is not possible to drain the hot water supply passage downstream of this check valve, and a new drain passage is provided downstream of the hot water supply passage so that this drainage can be performed. Forming the water heater complicates the piping configuration of the water heater and increases the size thereof.

[0009]

DISCLOSURE OF THE INVENTION The present invention solves such inconvenience, and when the water in the hot water supply passage is heated to a high temperature in the heat exchanger due to afterfire or the like, the high temperature hot water supplies the hot water upstream of the hot water supply. An object of the present invention is to provide a water heater that can quickly prevent backflow to the side with a simple configuration.

[0010]

In order to achieve such an object, the water heater of the present invention is a water heater for supplying hot water through a hot water passage passing through a heat exchanger, wherein the hot water heater is provided upstream of the heat exchanger. An openable and closable valve element provided in the passage and the valve element is engaged in the hot water supply passage by the valve body, and the valve body is opened and closed by thermal deformation according to the hot water temperature in the hot water supply passage at the position of the valve body. And a valve drive section made of a shape memory alloy, which is configured to be thermally deformed to drive the valve element to a closed position when the hot water temperature is equal to or higher than a predetermined temperature. .

[0011]

According to the water heater of the present invention, when the temperature of the hot water in the hot water supply passage in the heat exchanger becomes equal to or higher than the predetermined temperature at the position of the valve body, the valve drive section responds to the temperature. Is thermally deformed, and the valve body is closed by this thermal deformation. At this time, the hot water on the downstream side of the valve body, that is, the hot water on the heat exchanger side is prevented by the valve body from flowing backward to the upstream side of the valve body in the hot water supply passage. To be done. Since the valve drive section is made of a shape memory alloy,
When the temperature of the hot water in the hot water supply passage reaches a normal temperature, the hot water returns to its original shape, whereby the valve body is opened.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic configuration diagram of a water heater, and FIGS. 2 (a) and 2 (b).
3A and 3B are longitudinal sectional views of the thermal responsive valve applied to the water heater in an open state and a closed state, respectively. FIGS. 3A and 3B are open and closed states of other thermal responsive valves applied to the water heater, respectively. FIG.

In FIG. 1, the water heater 1 includes a heat exchanger 4 having a gas burner 3 in a body case 2, a hot water supply passage 5,
A drainage channel 6 for draining the hot water supply channel 5, and a heat exchanger 4
And a gas passage 7 for supplying gas to the gas burner 3.

In this case, the gas passage 7 is introduced into the main body case 2 through a gas introduction pipe 8 connected to a gas pipe (not shown) outside the main body case 2, and the safety gas valve 9 is introduced from the gas introduction pipe 8. The gas is supplied to the gas burner 3 through the gas amount adjusting mechanism 11, the gas valve 12, the gas governor 13, and the gas nozzle 14 which are operable via the gas amount adjusting handle 10 mounted on the outer surface of the body case 2. .

When the gas burner 3 is supplied with gas, the heat exchanger 4 ignites the gas burner 3 by an ignition device (not shown) in response to the gas, and at this time, the main body of the heat exchanger 4 is burned by the gas. The water flow in the hot water supply passage 5 is appropriately heated through the portion 15.

The piping structure of the hot water supply passage 5 is roughly divided into an upstream portion and a downstream portion, and an introduction water pipe 16 introduced from the outside into the main body case 2 and a water passage detection to the introduction water pipe 16 are sequentially performed. An intermediate water pipe 19 connected through the mechanism 17 and the water amount regulator 18, a heating water pipe 21 connected to the intermediate water pipe 19 via an overpressure relief valve 20, and a heating water pipe 21. And a lead-out water pipe 22 led out of the main body case 2. The introduction water pipe 16 is connected to a water pipe (not shown) outside the main body case 2 via a pipe 16a made of a resin material such as vinyl chloride, and the outflow water pipe 22 is provided outside the main body case 2, for example. Hot water supply faucet 23 and shower head 24
To hot water taps 25 and 26, respectively.
The heating water pipe 21 is wound around the main body 15 of the heat exchanger 4. Further, in the middle of the intermediate water pipe 19, a valve drive unit (details of which will be described later) made of a shape memory alloy, which is an essential part of the present invention, is provided with a heat-sensitive valve 27, and the heat passage of the outlet water pipe 22 is heated. Like the heat-sensitive valve 27, the heat-sensitive valve 28 having a shape memory alloy is provided near the water pipe 21.
(Details will be described later).

In this case, the water flow detection mechanism 17 has a known water governor 29 and a diaphragm 30.
As is well known, the flow of water in the hot water supply passage 5 is detected based on the water pressure received by the diaphragm 30, and the gas valve 12 of the gas passage 7 is opened and closed via a water governor 29 in response thereto.

The water amount adjuster 18 can be operated by a water amount adjusting handle 31 attached to the outer surface of the main body case 2, and the amount of water passing through the hot water supply passage 5 can be changed by this operation.

The drainage channel 6 is provided with the introduction water conduit 16
And at a location near the connection location of the water flow detection mechanism 17, is drawn out of the hot water supply channel 5 through the drain cock 32, and further through the drain pipe 33 (shown in phantom lines in the figure).
It is derived from the inside to the outside.

Next, the heat sensitive valve 27, which is an essential part of the present invention.
Will be described in detail with reference to FIGS. 2 (a) and 2 (b).

The heat-responsive valve 27 has a substantially cylindrical main body 34 and a substantially cylindrical valve body 35 having one end closed.
A spring 36 for urging the valve body 35 to the open position and a spring 37 which is a valve drive portion made of a shape memory alloy for opening / closing the valve body 35 according to the water temperature are provided.

In this case, an inlet side pipe connecting portion 38 and an outlet side pipe connecting portion 39 are formed at both open ends of the main body portion 34, and these pipe connecting portions 38 and 39 respectively have the intermediate portions. The upstream part and the downstream part of the water pipe 19 are connected (see FIG. 1). The inner peripheral surface portion of the main body portion 34 has a small-diameter inner peripheral portion 34a formed on the inlet-side pipe connecting portion 38 side and an outlet-side pipe connecting portion 39 from the small-diameter inner peripheral portion 34a through an inner peripheral step portion 34b. Large-diameter inner peripheral portion 3 formed on the side
4c and.

The valve body 35 has a large-diameter inner peripheral portion 34 of the main body 34.
It is inserted in the inside of c so as to be movable in the axial direction, and the inside of the main body 34 is opened and closed by the movement.

That is, the inlet side pipe connecting portion 3 of the valve body 35
The end portion on the 8th side is closed by a bottom wall portion 40 formed integrally with the outer peripheral side portion of the valve body 35, and the bottom wall portion 40 has a larger diameter than the small diameter inner peripheral portion 34a of the main body portion 34. Has been formed. Then, the peripheral edge portion of the end surface portion of the bottom wall portion 40 on the small diameter inner peripheral portion 34a side contacts the inner peripheral stepped portion 34b of the main body portion 34 when the valve body 35 is moved to the small diameter inner peripheral portion 34a side. The annular packing 41 that is in contact is fixed. Also, the valve body 3
The open end portion 42 of 5 is slidably contacted with the large-diameter inner peripheral portion 34c of the main body portion 34 over the entire circumference thereof, and a plurality of water passage holes 43 are formed in the outer peripheral side portion of the valve body 35.

Therefore, as shown in FIG. 2 (a), the valve body 35 is moved to the outlet side pipe connecting portion 39 side to move to the bottom wall portion 40.
Is separated from the inner peripheral stepped portion 34b of the main body portion 34 (hereinafter referred to as an open position), the inlet side pipe connecting portion 38 is provided inside the small diameter inner peripheral portion 34a of the main body portion 34, and the water passage hole 4 of the valve body 35.
3 and the large-diameter inner peripheral portion 34c of the main body portion 34 to communicate with the outlet-side pipe connection portion 39, and as shown in FIG. At the position where the portion 40 is pressed against the inner peripheral stepped portion 34b via the annular packing 41 (hereinafter referred to as the closed position), both pipe connection portions 3
8 and 39 are blocked by the bottom wall portion 40 and the annular packing 41.

A plurality of water passage holes 44 are formed in the large-diameter inner peripheral portion 34c of the main body portion 34 at a position between the open end portion 42 of the valve body 35 and the outlet side pipe connecting portion 39. The annular spring seat 45 is fixed, and the movement of the valve body 35 toward the outlet side pipe connection portion 39 side is restricted by the opening end 42 of the valve body 35 contacting the spring seat 45.

On the other hand, the spring 36 is interposed between the open end portion 42 of the valve body 35 and the inner peripheral stepped portion 34b of the main body portion 34, and biases the valve body 35 to the open position. Also,
The spring 37 made of a shape memory alloy is interposed between the bottom wall portion 40 of the valve body 35 and the spring seat 45, and biases the valve body 35 toward the closed position.

In this case, the spring 37 made of a shape memory alloy is made of a shape memory alloy in which the load generated according to the temperature of the water flowing backward from the outlet side pipe connecting portion 39 in the main body 34 changes as will be described later. For example, when the temperature of water flow is 80 ° C or less, the load becomes small,
When the temperature is above ℃, the load is large.

Then, as shown in FIG. 2A, when the load of the spring 37 is small, the generated load is made sufficiently smaller than the generated load of the spring 36. In this state, The load generated by the spring 36 becomes larger than the load generated by the spring 37,
The valve body 35 is moved to the open position by the urging force of the spring 36.

On the contrary, as shown in FIG. 2 (b), when the load of the spring 37 is large, the generated load is set to be sufficiently larger than that of the spring 36. Then, the generated load of the spring 37 becomes larger than the generated load of the spring 36,
The valve element 35 is moved to the closed position by the urging force of the spring 37.

Therefore, the spring 37 made of a shape memory alloy opens and closes the valve body 35 by a change in shape according to the temperature of the water flow.

Next, the structure of the heat sensitive valve 28 provided on the outlet water passage 22 will be described in detail with reference to FIGS. 3 (a) and 3 (b).

The heat-responsive valve 28 has a substantially cylindrical main body 46, and a substantially cylindrical valve body 47 concentrically inserted therein.
And a spring 48 for urging the valve body 47 to the open position.
And a spring 49 made of a shape memory alloy for opening and closing the valve body 47.

The tip portion of the main body portion 46 is closed by a bottom wall portion 46a formed integrally with the outer peripheral side portion thereof, and an inlet side pipe connecting portion 50 is formed at the open rear end portion thereof. An outlet side pipe connecting portion 51 that communicates with the inlet side pipe connecting portion 50 through the inside of the main body portion 46 is formed at a position near the bottom wall portion 46 a on the outer peripheral side portion of the main body portion 46.

In this case, the upstream and downstream portions of the outlet water passage 22 are connected to the two pipe connection portions 50 and 51 of the heat-responsive valve 28 (see FIG. 1).

The valve body 47 is inserted in the main body portion 46 so as to be movable in the axial direction thereof.
The inside of 6 is opened and closed between the two pipe connecting portions 50 and 51.

That is, on the inner peripheral surface of the main body portion 46, the portion between the two pipe connecting portions 50 and 51 and the outlet side pipe connecting portion 5
1 and the portion between the bottom wall portion 46a and the main body portion 46, respectively.
Of the inclined surface 5 whose diameter gradually decreases toward the bottom wall portion 46a side of the
2, 53 are formed, and when the valve body 47 is moved toward the bottom wall portion 46a side in the outer peripheral portion of the rear end portion of the valve body 47 and the outer peripheral portion of the tip end portion, respectively. As shown in FIG. 3B, the O-rings 54 and 55 which are slidably in contact with the inclined surfaces 52 and 53 over the entire circumference are attached. And the valve body 4
As shown in FIG. 3 (a), 7 is an inlet side pipe connecting portion 50.
And the O-rings 54 and 55 are moved toward
In the state of being separated from 2, 53, a gap 5 is formed between the rear end portion and the front end portion of the valve body 47 and the inner peripheral surface of the main body portion 46.
6, 57 are formed.

Therefore, as shown in FIG. 3A, the valve body 47 is moved to the inlet side pipe connecting portion 50 side (hereinafter,
In the open position), both pipe connection parts 50 and 51 are separated by a gap 5
6 or through the inside of the valve body 47 and the gap 57, and as shown in FIG.
At a position where the O-rings 54 and 55 are moved to the 6a side and slidably contact the inclined surfaces 52 and 53 (hereinafter, referred to as a closed position), the two pipe connecting portions 50 and 51 are shut off via the O-rings 54 and 55.

An annular spring seat 58 is fixed to the inner peripheral surface of the main body portion 46 at a position between the rear end of the valve body 47 and the inlet side pipe connecting portion 50, and the inlet of the valve body 47 is fixed. The movement toward the side pipe connecting portion 50 side is restricted by the stopper 59 fixed to the rear end portion of the valve body 47 coming into contact with the spring seat 58.

On the other hand, the spring 48 has an annular jaw portion 60 and a body portion 46 formed in the intermediate portion of the inner peripheral surface of the valve body 47.
Is interposed between the bottom wall portion 46a and the bottom wall portion 46a and urges the valve body 47 toward the open position. Further, the spring 49 made of a shape memory alloy is interposed between the annular jaw portion 60 of the valve body 47 and the spring seat 58, and biases the valve body 47 toward the closed position.

In this case, the spring 49 made of a shape memory alloy is generated in accordance with the temperature of the water flowing from the inlet side pipe connecting portion 50 in the main body portion 46, like the spring 37 of the heat-responsive valve 27. It is made of a shape memory alloy whose load changes. For example, when the temperature of water flow is 80 ° C or lower, the load is small, and when it is 90 ° C or higher, the load is large.

As shown in FIG. 3 (a), when the load of the spring 49 is small, the generated load is made sufficiently smaller than the generated load of the spring 48. In this state, The load generated by the spring 48 becomes larger than the load generated by the spring 49,
The valve body 47 is moved to the open position by the urging force of the spring 48.

On the contrary, as shown in FIG. 3B, when the load of the spring 49 is large, the generated load is made sufficiently larger than that of the spring 48. Then, the load generated by the spring 49 becomes larger than the load generated by the spring 48,
The valve body 47 is moved to the closed position by the urging force of the spring 49.

Therefore, the spring 49 made of a shape memory alloy also opens and closes the valve body 47 by changing the shape according to the temperature of the water passing through it.

Since the valve body 47 of the heat-responsive valve 28 penetrates the inside thereof, it does not move from the open position to the closed position depending on the water flow from the inlet side pipe connecting portion 50. .

Next, the operation of the water heater 1 will be described.

In FIG. 1, in the water heater 1, when one of the hot water taps 25 and 26 is opened, the introduction water pipe 16 to the intermediate water pipe 19, the heating water pipe 21, and the outflow water pipe 22 of the hot water supply passage 5 are opened. Water is supplied to the faucet 23 or the shower head 24 through the.

At this time, the water flow in the hot water supply passage 5 is detected by the diaphragm 30 of the water flow detecting mechanism 17 provided in the hot water supply passage 1, and in response to this, the water governor 29 causes the gas valve 12 in the gas passage 7 to operate. Is opened. Then, when the gas valve 12 is opened, as described above, the gas is supplied to the gas burner 3 of the combustor 4 through the gas passage 7, and the gas is burned, whereby the water in the hot water supply passage 1 is discharged. Is heated in the heating water pipe 21 via the main body portion 15 of the heat exchanger 4. By this heating, hot water is supplied to the faucet 23 or the shower head 24.

In this case, the hot water supply temperature is set to a normal temperature of, for example, 40 to 50 ° C. by a user or the like through an operation device (not shown), and the heat exchanger 4 is set to the hot water supply temperature. The operation is appropriately controlled by a controller (not shown) so as to reach the set temperature.

At such a normal hot water supply temperature, as shown in FIGS. 2 (a) and 3 (a), the springs 37, 49 made of a shape memory alloy of the heat-responsive valves 27, 28 are formed. Since the generated load is small, the valve elements 35 and 47 of the heat-responsive valves 27 and 28 have been moved to the open position.

On the other hand, in the hot water supply device 1, when the water governor 29 of the water flow detection mechanism 17 or the diaphragm 30 malfunctions, for example, the gas valve 12 does not flow in the hot water supply passage 5. There is a case where a so-called afterglow occurs in the heat exchanger 4 in this case, and in this case, although the operation of the heat exchanger 4 is stopped by the overheating prevention device (not shown), the heating water pipe of the hot water supply passage 5 The water in 21 may be heated to a high temperature by the afterglow and its pressure may become high. In this case, although the pressure of the heating water passage pipe 21 is set by the overpressure relief valve 20 so as not to exceed, for example, 17.5 kgf / cm ² , the boiling point of water also rises at such a high pressure. Thus, the water in the heating water pipe 21 may be heated to, for example, 150 to 180 ° C.

Since the water in the heating water pipe 21 is heated to a high temperature and its pressure rises in this way, the heated high-pressure hot water flows from the side of the heating water pipe 21 to the heat-sensitive valve 2.
7. When attempting to backflow to the resin pipe 16a via the intermediate water pipe 19 and the introduction water pipe 16, when such a backflow occurs, the resin pipe 16a may be damaged by the hot water.

However, at this time, as shown in FIG. 2 (b), the high temperature hot water in which the spring 37 made of the shape memory alloy of the thermoresponsive valve 27 tries to flow backward from the outlet side pipe connecting portion 39 into the main body portion 34. When the valve body 35 is immediately moved to the closed position due to contact with the valve body 35, the hot water flows from the heating water pipe 21 side to the intermediate water pipe 19.
Is prevented from flowing backwards. Further, in this case, since the high-temperature hot water that is about to flow backward from the outlet side pipe connection portion 39 into the main body portion 34 has a high pressure, the pressure acts on the bottom wall portion 40 of the valve body 35 and the valve is closed. The movement of the body 35 to the closed position is promoted.

Therefore, the hot water does not flow back from the heating water pipe 21 to the introduction water pipe 16 or the pipe 16a, and the resin pipe 16a is not damaged by the hot water.

In this case, the spring 37 made of a shape memory alloy is provided at a location which is always in communication with the heating water passage 21 side through the outlet side pipe connecting portion 39, so that the load of the spring 37 is reduced. The large state is maintained until the hot water temperature on the side of the heating water pipe 21 decreases, and therefore the valve body 3
7 is maintained in the closed position.

Further, in FIGS. 1 and 3, as described above, when the hot water taps 25 and 26 are opened in a state where the water in the heating water pipe 21 is heated to a high temperature by the afterglow or the like, the heating water pipe is opened. The hot water in 21 is discharged through the heat-responsive valve 28
Try to flow to the downstream side.

However, as shown in FIG. 3 (a), at this time, when hot water flows from the heating water passage pipe 21 into the main body portion 46 through the inlet-side pipe connection portion 50 of the heat-responsive valve 28, Since the high-temperature hot water directly contacts the spring 49 made of the shape memory alloy of the heat-responsive valve 28, immediately, as shown in FIG.
As shown in (b), the spring 49 is in a state where the generated load is large, and the valve body 47 is moved to the closed position. As a result, the outlet-side pipe connection portion 51 of the heat-responsive valve 28 is connected to the valve body 47. It is cut off from the inlet side pipe connecting portion 50 via the O-rings 54 and 55. Therefore, the high-temperature hot water flowing into the main body 46 from the heating water passage 21 does not flow out to the downstream side of the outlet water passage 23, whereby the high-temperature hot water is supplied to the faucet 23 and the shower head 24. Are blocked.

In this case, the spring 49 made of a shape memory alloy is provided at a location which is always in communication with the heating water passage pipe 21 through the inlet side pipe connecting portion 50, so that the load of the spring 49 is The large state is maintained until the temperature of the hot water in the heating water pipe 21 decreases, and thus the valve element 49 is maintained in the closed position.

As described above, in such a water heater 1,
When the afterfire of the heat exchanger 4 occurs, the hot and high-pressure hot water is prevented from flowing backward to the introduction water pipe 16 or the pipe 16a promptly by the heat-responsive valve 27. Supply to the shower head 23 and the shower head 24 is promptly prevented by the heat sensitive valve 28.

In the water heater 1 shown in FIG. 1, the heat-responsive valves 27 and 28 are normally open. Therefore, when the drain cock 32 is opened, the hot water supply passage 5 is opened.
The water inside is drained through the drainage channel 6 and the drainage pipe 33 without any trouble.

[0061]

As is clear from the above description, according to the water heater of the present invention, the openable and closable valve element provided in the hot water supply passage on the upstream side of the heat exchanger is provided at the position of the valve element. By driving the valve drive unit made of shape memory alloy to the closed position when the temperature is equal to or higher than a predetermined temperature, water in the hot water supply passage is heated to a high temperature in the heat exchanger due to afterfire, etc. In the event of a failure, the high-temperature, high-pressure hot water can be reliably and quickly prevented from flowing backward to the upstream side of the hot water supply passage, and the water in the hot water supply passage can be drained normally without any trouble. .

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a water heater according to the present invention;

2A is a longitudinal sectional view of an example of a thermal responsive valve as an essential part of the present invention in an open state, FIG. 2B is a longitudinal sectional view of the thermal responsive valve in a closed state,

FIG. 3A is a vertical cross-sectional view of a thermoresponsive valve having a shape memory alloy provided in the water heater in an open state, and FIG. 3B is a vertical cross-sectional view of the thermosensitive valve in a closed state.

[Explanation of Codes] 1 ... Water heater, 4 ... Heat exchanger, 5 ... Hot water supply passage, 27 ... Heat sensitive valve, 35 ... Valve body, 37 ... Spring (valve drive section) made of shape memory alloy.

Claims (1)

(57) [Claims] 1. A water heater for supplying hot water through a hot water supply passage that passes through a heat exchanger, wherein an openable and closable valve element is provided in the hot water supply passage upstream of the heat exchanger, and in the hot water supply passage. A valve drive unit that is engaged with the valve body and that opens and closes the valve body by thermal deformation according to the hot water temperature in the hot water supply path at the position of the valve body, the valve drive unit comprising: A water heater configured to be thermally deformed to drive the valve body to a closed position when the temperature of the hot water is equal to or higher than a predetermined temperature.