JPH11311449A - Combustion equipment and non-return device thereof having overpressure prevention function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the water pressure of a conduit down stream of a non-return device from becoming high-pressure when the water supply is stopped. SOLUTION: A non-return device 17 is disposed in a water supply passage of a combustion equipment. This non-return device is provided with a fluid passage 48 for allowing water pass therethrough from an inlet opening 46 to an outlet opening 47. A backflow prevention valve seat 50 and a non-return valve disk 51 are disposed in the inside of a flow passage 48 so as to prevent the backflow from the outlet opening 47 side to the inlet opening 46 side. A communication passage 61 which makes the flow passage 48 disposed at the inlet opening side than the valve disk 51 and the flow passage 48 disposed at the outlet opening side than the valve disk 51 communicating with each other is formed in the inside of the backflow prevention valve body 51. A valve seat 63 and a valve body 64 are formed in the communication passage 61. In the condition that the backflow prevention valve seat 50 is closed, when the water pressure of the outlet opening side become higher than the pressure of the inlet opening side by not less than a predetermined difference, the valve disk 64 is removed from the valve seal 63 so that water passes through the communication passage 61 thus releasing the excessive water pressure of the outlet opening side to the inlet opening side. Since the excessive water pressure of the outlet opening side can be released, the water pressure of the outlet opening side is prevented from becoming high-pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion apparatus provided with a check device for preventing a flow of hot water flowing backward from a hot water supply heat exchanger, and a check device having an overpressure preventing function.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a system configuration of a one-can, two-channel bath water heater which is a combustion device developed by the applicants. In this figure, this one-can, two-channel bath water heater (apparatus) has a combustion chamber 1, in which a burner 2 serving as a heating means is disposed. A heat exchanger 3 and a reheating heat exchanger 4 which is another function heat exchanger are provided. The hot water supply heat exchanger 3 and the reheating heat exchanger 4 are disposed integrally. In other words, a hot water supply heat exchanger 3 is formed by penetrating a plurality of common fin plates 5 with a hot water supply-side pipe, and a reheating heat exchanger is similarly mounted by penetrating a fin plate 5 with a refueling-side pipe. The burner 2 heats both the hot water supply heat exchanger 3 and the reheating heat exchanger 4.

The combustion chamber 1 below the burner 2 communicates with an air supply passage 6, and a combustion fan 7 is incorporated in the air supply passage 6. Air is sent to the burner 2 via the burner 6, and exhaust gas generated by combustion of the burner 2 is discharged to the outside from an exhaust passage 9 communicating with the combustion chamber 1 above the burner 2.

[0004] A gas nozzle 19 is provided opposite to the gas inlet of the burner 2, and the gas nozzle 19 is connected to a gas supply passage 8 for introducing a fuel gas.
The fuel gas guided by the gas supply passage 8 is supplied to the burner 2 via a gas nozzle 19. The gas supply passage 8 has solenoid valves 10 and 11 for opening and closing the passage.
a, 11b, and a proportional valve 12 for controlling the gas supply amount based on the valve opening amount.

[0005] A water supply passage 1 is provided on the inlet side of the hot water supply heat exchanger 3.
3 is connected to one end of a hot water supply heat exchanger 3, and one end of a hot water supply passage 14 is connected to the outlet of the hot water supply heat exchanger 3.
Is connected to a water supply source through an external pipe, and the other end of the hot water supply passage 14 is guided to a desired hot water supply place such as a kitchen through the external pipe. The hot water supply heat exchanger 3
A bypass passage 15 for short-circuiting the inlet-side water supply passage 13 and the outlet-side hot water supply passage 14 is provided. The bypass passage 15 is provided with a bypass valve 16 for opening and closing the passage.

A line 1 is provided on the inlet side of the reheater 4.
8 is connected, the other end of the conduit 18 is connected to the discharge port of the circulation pump 20, one end of the return pipe 21 is connected to the suction port of the circulation pump 20, and the return pipe 21
Is connected to the bathtub 22 at the other end. One end of a pipe 23 is connected to the outlet side of the reheater 4, and the other end of the pipe 23 is connected to the bathtub 22. The return line 21, the circulation pump 20, the line 18, the reheating heat exchanger 4 and the line 23 make up the reheating circulation passage 2.
4 are configured.

The pipe line 18 of the additional heating circulation passage 24 and the hot water supply passage 14 are communicated by a hot water supply passage 25. The hot water supply passage 25 has a pouring control valve 26 for controlling opening and closing of the passage, and a bathtub. And a water level sensor 28 for detecting the water level of the pump 22 by water pressure.

Reference numeral 30 shown in the figure is an air volume sensor for detecting the air volume in the combustion chamber 1, 31 is a water volume sensor provided in the water supply passage 13 for detecting the flow rate of the water supply, and 32
Reference numeral 34 denotes an incoming water temperature sensor for detecting the temperature of water in the water supply passage 13, reference numeral 34 denotes a flow control valve provided in the hot water supply passage 14 to control the flow rate of water, and reference numeral 35 denotes a flow control valve provided in the hot water supply passage 14 Reference numeral 36 denotes a hot water supply confirmation switch for detecting that water is flowing, a reference numeral 36 denotes a water flow sensor for detecting the flow of water in the reheating circulation passage 24, and reference numeral 37 denotes a temperature (bath temperature) of hot water in the reheating circulation passage 24 in the bathtub. Is a bath temperature sensor for detecting the temperature of the hot water produced by the hot water supply heat exchanger 3.

[0009] This one-can-two-channel water heater has a control device 4
0 is provided, and the remote controller 4
1 is connected. The remote controller 41 is provided with a hot water supply temperature setting means for setting a hot water supply temperature, a bath temperature setting means for setting a bath temperature of the bathtub 22, a bath water level setting means for setting a water level of hot water in the bathtub 22, and the like. ing.

The control device 40 takes in sensor output signals of various sensors and information of the remote controller 41, and performs various operations such as hot water supply operation, hot water filling operation, reheating operation and the like according to the information and a sequence program given in advance. The operation of the appliance operation is controlled as follows.

For example, when the hot water tap 39 of the hot water supply passage led to the kitchen or the like is opened and water flows from the water supply source into the water supply passage 13 and the water amount sensor 31 detects the water flowing through the water supply passage 13, the appliance is turned on. Start driving. First, the combustion fan 7
Of the solenoid valve 11a, 11b and / or one of the solenoid valves 11b, and the solenoid valve 10 is opened to supply fuel gas to the burner 2 through the gas supply passage 8, and the burner 2 is turned on by a not shown ignition means. To start combustion.

The proportional valve 12 is controlled so that the hot water temperature becomes the hot water set temperature set in the hot water temperature setting means.
By controlling the valve opening amount (by controlling the amount of gas supplied to the burner 2), the combustion capacity of the burner 2 is controlled, and the hot water supply heat exchanger 3 is controlled.
Is heated by the combustion flame of the burner 2 to produce hot water of a set temperature, and this hot water is supplied to a hot water supply place through a hot water supply passage 14.

When the use of hot water is finished and the hot water tap 39 is closed, the flow of water to the hot water supply heat exchanger 3 is stopped and the water flow sensor 3 is turned off.
When 1 stops detecting the flow of water through the water supply passage 13, the electromagnetic valve 10 is closed to stop the combustion of the burner 2. After that, when a predetermined post-purge period (for example, 5 minutes) has elapsed, the rotational drive of the combustion fan 7 is stopped to end the hot water supply operation and prepare for the next hot water supply.

When performing the filling operation, for example, the pouring control valve 26 is opened, and water flows from the water supply source into the water supply passage 13 by the opening operation of the pouring control valve 26, and the water amount sensor 31 supplies water. When the passage of water through the passage 13 is detected, the combustion of the burner 2 is started in the same manner as in the hot water supply operation.

Hot water produced in the hot water supply heat exchanger 3 by the combustion flame of the burner 2 is supplied to the hot water supply passage 14 and the hot water supply passage 2.
The hot water that has been sent to the reheating circulation path 24 through the pipes 5 in sequence and flows into the reheating circulation path 24 passes through the return pipe 21 to the bathtub 22 and the path that reaches the bathtub 22 via the reheating heat exchanger 4. Are dropped into the bathtub 22 by two routes. When the water level in the bathtub 22 detected by the water level sensor 28 reaches the set water level set in the remote controller 41, the pouring control valve 26 is closed, the solenoid valve 10 is closed, and the combustion of the burner 2 is stopped. Terminate the hot water operation.

When performing the reheating operation, the circulation pump 20 is driven to circulate the water in the bathtub 22 through the reheating circulation passage 24, and the bath temperature detected by the bath temperature sensor 37 is set by the bath temperature setting means. When the temperature is lower than the set temperature, the water flow sensor 36
, The combustion of the burner 2 is started, and the circulating hot and cold water of the reheating heat exchanger 4 is heated by the combustion flame of the burner 2 to perform reheating. And the bath temperature sensor 3
When the bath temperature detected by 7 reaches the set temperature, the combustion of the burner 2 is stopped, and the reheating operation is terminated.

By the way, when the one-can-two-water-bath water heater does not perform the hot-water supply operation including the hot-water supply operation but performs the re-heating alone operation only for the re-heating operation, hot water stays in the hot-water supply heat exchanger 3. In this state, not only the reheated heat exchanger 4 but also the hot water supply heat exchanger 3 is burned and heated, and the temperature of the retained hot water in the hot water supply heat exchanger 3 rises to a very high temperature.

For this reason, when hot water supply is started during the reheating alone operation, immediately after the reheating alone operation, or the like, if the hot water supply heat exchanger 3 is heated to a high temperature due to the reheating alone operation.
There is a possibility that the hot water in the hot water flows out, giving the user of the hot water discomfort due to the high-temperature hot water, or causing a serious problem that the high-temperature hot water causes a burn to the user of the hot water.

The applicants have proposed means for avoiding the high-temperature hot water by intermittently burning the burner during the reheating alone operation. For example, a hot water supply hot water temperature sensor 33 shown by a dashed line in FIG. 3 for detecting the temperature of hot water in the hot water supply heat exchanger 3 is provided, and an OFF temperature and an ON temperature lower than the OFF temperature are given in advance. Hot water supply heat exchanger 3 detected by hot water supply hot water temperature sensor 33 during reheating alone operation
When the temperature of the hot water in the inside becomes higher than the above-mentioned off temperature, the combustion of the burner 2 is stopped, and when the temperature of the hot water in the hot water supply heat exchanger 3 falls below the above-mentioned on temperature, the combustion of the burner 2 is restarted. As described above, the burner combustion is intermittently performed during the reheating alone operation based on the temperature detected by the hot water supply hot water temperature sensor 33.

As described above, by intermittently stopping the combustion of the burner 2 during the reheating alone operation, the temperature of the hot water in the hot water supply heat exchanger 3 can be reduced during the burner combustion stop period. It is possible to prevent the staying hot water in the hot water supply heat exchanger 3 from becoming in a state close to boiling, and to avoid high-temperature hot water caused by the reheating alone operation.

Incidentally, during the reheating alone operation, the accumulated hot water in the hot water supply heat exchanger 3 is heated as described above, and the heated hot water tends to flow back to the water supply side due to volume expansion.
However, when the hot and cold water in the hot water supply heat exchanger 3 flows due to volume expansion, the hot water temperature detected by the hot water supply hot water temperature sensor 33 is disturbed, and the hot water is detected as described above based on the hot water temperature detected by the hot water supply hot water temperature sensor 33. In the case where the burner intermittent combustion is performed during the single operation of baking, there is a problem that the intermittent burner causes hunting due to the disturbance of the detected hot water temperature.

Therefore, as shown in FIG.
Is provided with a check valve 17 as a check device, and the check valve 17 prevents the flow of hot and cold water in the hot water supply heat exchanger 3 during the independent heating operation to avoid the hunting problem of the burner intermittent combustion. It is configured as follows.

By providing the check valve 17, the following effects can be obtained. For example,
If the check valve 17 is not provided, the reheating only operation or the post-heating (after the hot water supply operation or the hot water filling operation is completed, the hot water supply When the temperature of the accumulated hot water in the hot water supply heat exchanger 3 increases due to the heat retained in the heat exchanger 3 heating the hot water in the hot water supply heat exchanger 3 to increase the hot water temperature, the temperature of the hot water increases. Hot water flows backward from the hot-water supply heat exchanger 3 to the water supply passage 13 side, and the hot-water temperature near the set hot-water supply temperature may be detected by the back-flow hot water in some cases.

As described above, the high temperature of the hot water is applied to the incoming water temperature sensor 3.
When the hot water supply is started from the state detected by the hot water supply 2, since the hot water temperature close to the hot water supply set temperature is detected from the incoming water temperature sensor 32, the combustion of the burner 2 does not start immediately. In such a case, when the hot water supply is started, it is possible to supply hot water at almost the set hot water supply temperature, but immediately thereafter, unheated water will be supplied, and the hot water at the start of hot water supply will be supplied. There is a problem that temperature fluctuations become severe.

By providing the check valve 17, when the hot water staying in the hot water supply heat exchanger 3 is heated during the hot water supply stop due to the post-boiling or reheating alone operation, Since the heated hot and cold water is prevented from flowing backward from the hot water supply heat exchanger 3 to the water supply passage 13, the above-described fluctuation in the hot water temperature at the start of hot water supply can be avoided.

Further, as described above, it is possible to prevent the high-temperature hot water of the hot-water supply heat exchanger 3 from flowing back into the water supply passage 13 due to the post-boil or reheating alone operation while the hot water supply is stopped. It is also possible to prevent a sensor having low heat resistance such as the water amount sensor 31 from being damaged by the high-temperature hot water.

[0027]

However, it has been found that the following problems occur when the check valve 17 is provided in the water supply passage 13 as described above. During the stop of hot water supply, the check valve 17, the pouring control valve 26 and the hot water tap 3
9, a hot-water-side passage including a passage portion from the check valve 17 to the hot-water tap 39 through the hot-water supply heat exchanger 3 and a hot-water filling passage 25 from the passage portion to the pouring control valve 26. Is in a closed state, and in this state, the accumulated water in the hot water supply heat exchanger 3 expands in volume by heating the accumulated water in the hot water supply heat exchanger 3 due to the post-boiling or reheating alone operation. The water pressure in the hot water passage (hot water pressure) increases.
In particular, during the reheating alone operation, the hot water side water pressure becomes extremely high, for example, about 15 kg / cm ² or more.

As described above, when the hot water side water pressure is extremely high due to the above-mentioned post-boiling or reheating alone operation, the pouring control valve 26 is opened by the start of filling,
When the hot water tap 39 is opened and hot water supply is started, the hot water pressure drops sharply, and the sudden fluctuation of the hot water pressure causes a shock wave in the hot water passage to generate a loud noise. Hammer happens. As described above, when the water hammer is generated, there is a problem that the user of the combustion device is concerned about whether the combustion device is abnormal.

The provision of the check valve 17 in the water supply passage 13 may cause the following problem.
As shown in FIG. 3, when the hot water tap 39 is provided on the outlet side of the hot water supply passage 14, as described above, while the hot water supply is stopped, the hot water supply heat exchanger is caused due to the post-boil or reheating alone operation. When the retained hot water in 3 is heated to a high temperature and the hot water pressure becomes high due to volume expansion, there is a problem that it becomes difficult to open the hot water tap 39 by manual operation due to the high hot water pressure. In particular, when the hot water tap 39 is a mixed water tap 75 with temporary water stoppage as shown in FIG. 6, it becomes very difficult to open the hot water tap 39 due to the increase of the hot water pressure. It is a big problem.

The mixing faucet 75 with temporary water stop shown in FIG.
Is to mix hot and cold water flowing out of the combustion equipment with unheated water supplied from the water supply source side, and to supply the mixed hot and cold water to a hot water supply location, and has a temporary water stopping function. I have. In other words, the mixing faucet 75
Is provided with a temporary water stop valve 78 in addition to the hot water control valve 76 and the water control valve 77. The hot water amount adjusting valve 76 adjusts the amount of hot water supplied from the combustion equipment by the valve opening degree, and the valve opening degree is manually adjusted using the hot water amount adjusting operation section 80. The water amount adjusting valve 77 adjusts the amount of water supplied from the water supply source side with the valve opening, and the valve opening is manually adjusted using the water amount adjusting operation section 81. Further, the temporary water stop valve 78 is used to supply and stop the mixed hot water by manual operation of the temporary water stop operation unit 82. The temporary water stop valve 78 can be used to temporarily stop the hot water supply. it can.

The mixing faucet 75 with temporary stoppage as shown in FIG. 6 has check valves 8 on the hot water inlet side of the hot water adjusting valve 76 and on the water supply inlet side of the water adjusting valve 77, respectively.
4,85 are required. As described above, the check valve 17 is provided on the inlet side of the water supply passage 13 of the combustion device. Further, the check valves 84 and 85 are provided on the hot water inlet side and the water inlet side of the mixing faucet 75 with temporary stop water, respectively. In the case of the interposed structure, when the hot water staying in the hot water supply heat exchanger 3 is heated due to the post-boil or the additional heating alone while the hot water supply is stopped, the reverse operation shown in FIG. There is a case where the pipe portion Z between the stop valve 84 and the hot water amount adjusting valve 76 has a very high pressure. In this case, the temporary water stop operation section 82 of the temporary water stop valve 78
Is very difficult to operate, and it is difficult to open the temporary water stop valve 78.

In addition, the hot water supply heat exchanger 3 and the additional heating heat exchanger 4 as shown in FIG. 4 are provided separately, and the burner is provided separately for each of the hot water supply heat exchanger 3 and the additional heating heat exchanger 4. A non-return valve for preventing backflow in the water supply passage 13 also in a combustion device other than the one-can-two-water-channel type, such as a two-pipe two-channel type combined combustion device or a water heater with a single function of hot water supply as shown in FIG. There is a case where the valve 17 is provided, and in such a combustion apparatus with the check valve 17, there is a risk of occurrence of the above-described water hammer and a problem of difficulty in opening the hot water tap 39.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the invention is to provide a combustion apparatus having a check device in a water supply passage, a single operation of reheating or a hot water supply while a hot water supply is stopped. When the hot water in the hot water supply heat exchanger is heated to a high temperature due to the post boiling of the heat exchanger, etc., the hot water pressure is prevented from increasing to a high pressure. It is an object of the present invention to provide a combustion device and a check device with an overpressure prevention function capable of preventing generation of a water hammer and preventing the opening operation of a hot water tap from becoming difficult. .

[0034]

Means for Solving the Problems In order to achieve the above object, the present invention has the following structure to solve the above problems. That is, a first invention is a hot water supply heat exchanger for heating water supplied from a water supply passage to supply hot water, and a check device provided in the water supply passage for preventing a flow of hot water flowing backward from the hot water supply heat exchanger side. A combustion device provided with: a counter pressure when a pressure difference between a feed water pressure on the upstream side of the check device and a hot water pressure on the downstream side of the check device is equal to or higher than a predetermined pressure difference. This is a means for solving the above-mentioned problem by providing an overpressure prevention means for releasing excess water pressure on the downstream side of the stop device to the upstream side.

According to a second aspect of the present invention, there is provided a check device according to the first aspect, wherein an inlet for taking in water, an outlet for flowing out the taken-in water, A flow passage communicating with the outlet is provided, and a check valve seat is provided on an inner peripheral wall portion of the flow passage. A check valve that closes from the side is provided, and inside the check valve, a flow passage closer to the inlet than the valve and a flow passage closer to the outlet than the valve. Is formed, and when the pressure difference between the water pressure on the upstream side and the water pressure on the downstream side of the check device is equal to or higher than a predetermined pressure difference, the communication passage is brought into the water flowing state. An overpressure relief valve is provided, and the overpressure relief valve and the communication passage form overpressure prevention means. With a configuration that forms a built-in configuration of the preventing means is a means for solving the above problems.

According to a third aspect of the present invention, there is provided a bypass passage for short-circuiting the upstream side and the downstream side of the check device constituting the first aspect of the present invention, and the overpressure preventing means is provided with an overpressure provided in the bypass passage. The overpressure relief valve is opened when the differential pressure between the upstream feedwater pressure and the downstream hotwater pressure of the check device is equal to or higher than a predetermined differential pressure. The above-mentioned problem is solved by a configuration in which excess water pressure on the downstream side of the stop device is released to the upstream side through the bypass passage.

The fourth invention is directed to the first, second, or third aspect.
The other function heat exchanger performing functions other than hot water supply is provided integrally with the hot water supply heat exchanger, and the integrated hot water supply heat exchanger and the other function heat exchanger are shared. Means for solving the above-mentioned problem is a configuration of a single-can double-channel type combustion device provided with a burner for burning and heating.

According to a fifth aspect of the present invention, there is provided the configuration of any one of the first to fourth aspects of the present invention, further comprising a heating means for heating the hot water supply heat exchanger. Means for solving the above-mentioned problem with a configuration in which a hot water retention control section for retaining hot water in a hot water supply heat exchanger is provided which performs drive control of the heating means in accordance with a predetermined control procedure for keeping hot water retained in the vessel. And

According to a sixth aspect of the present invention, there is provided the configuration of any one of the first to fifth aspects of the present invention, wherein the hot water and hot water produced by the hot water supply heat exchanger and flowing out of the combustion equipment are heated. The present invention is a means for solving the above-mentioned problem with a configuration in which no water is mixed and the mixed hot and cold water is supplied to a hot water supply place.

According to a seventh aspect of the present invention, there is provided an overpressure prevention function for a combustion device which is provided in a water supply passage for supplying water to a hot water supply heat exchanger of the combustion device and which prevents a flow of hot water flowing backward from the hot water supply heat exchanger side. A non-return device, provided with an inflow port for taking in water, an outflow port for outflowing the taken-in water, and a flow path communicating between the inflow port and the outflow port; A non-return valve seat is provided on the inner peripheral wall of the non-return valve, and a non-return valve body is provided to face the non-return valve seat and close the valve seat from the outflow side by spring pressure. In the inside of the check valve, there is formed a communication passage communicating the flow passage on the inlet side with respect to the valve body and the flow passage on the outlet side with respect to the valve body, and the upstream side of the check device. When the pressure difference between the water pressure of the downstream side and the water pressure of the downstream side higher than the water pressure of the upstream side is equal to or higher than a predetermined pressure difference, An over-pressure relief valve for providing a water flow state is provided, and the check valve seat is closed by the check valve to prevent the flow of hot water flowing backward from the hot water supply heat exchanger. When the pressure difference between the water pressure on the upstream side and the water pressure on the downstream side of the device is equal to or higher than a predetermined pressure difference, the overpressure relief valve allows the communication passage to pass through and the excess water pressure on the downstream side of the check device is reduced. A means for solving the above-mentioned problem has a configuration characterized in that it escapes to the upstream side through the inside of the check device.

In the invention having the above-described structure, for example, the water pressure on the downstream side of the check device is higher than the water pressure on the upstream side by a predetermined pressure difference due to the post-boiling of the hot water supply heat exchanger. When the pressure rises, the overpressure prevention means releases the excessive hot water pressure to the upstream side of the check device, prevents the hot water pressure from increasing, and reduces the hot water pressure by generating a water hammer or opening the hot water tap. Water pressure is controlled to avoid difficulties in operation.

As described above, it is possible to suppress the increase of the hot water side water pressure, so that the occurrence of a water hammer at the start of filling or the start of hot water supply is prevented. Further, it is possible to prevent the problem that the hot water tap provided in the passage on the hot water supply side of the combustion equipment becomes difficult to open due to the increase in the hot water pressure, and the above-mentioned problem is solved.

[0043]

Embodiments of the present invention will be described below with reference to the drawings.

The combustion apparatus shown in the first embodiment has a structure provided with a check valve for preventing backflow of hot water to the water supply side. For example, a check valve as shown in FIG. A one-can two-channel water heater with a valve 17, a two-pipe two-channel water heater with a check valve 17 as shown in FIG. 4, a single-function water heater with a check valve 17 as shown in FIG. 5, etc. For combustion equipment. In the description of this embodiment, the description of the system configuration of FIGS. 3, 4, and 5 has been described above, and therefore, redundant description will be omitted.

The features of this embodiment are as follows.
The check device with overpressure prevention function as shown in FIG.
7 is provided.

FIG. 1 shows a cross-sectional view of a check device having an overpressure preventing function, which is characteristic of the first embodiment, together with fittings (joints) to be incorporated in the water supply passage 13. As shown in the figure, the check valve 17 has a first pipe 43 and a second pipe 44, and the first pipe 4
On one end side of 3, a screw portion 43a for screwing connection with the connection fitting is formed on the inner peripheral wall, and the first pipe 43 and the connection fitting are screwed together. The other end of the first tube 43 is provided with a screw portion 43 for screw connection with the second tube 44.
b is formed on the inner peripheral wall, and a screw portion 44a corresponding to the screw portion 43b is formed on the outer peripheral wall of the second tubular body 44. The first tubular body 43 and the second tubular body 44 The composite pipe 45 is screwed and connected.

Further, the first tube 4 is formed by the screw connection.
A packing housing groove 44b is formed in the outer peripheral wall portion of the second pipe body 44 that enters the inside of the gasket 3, and the packing housing groove 44b is formed.
An O-ring 49 is housed in b to prevent water from leaking from the connection between the first tube 43 and the second tube 44.

One end of the composite tube 45 (the second tube 4
The opening on the side 4) is an inlet 46 for taking in water.
The opening at the other end (on the side of the first pipe 43) forms an outlet 47 through which the captured water flows out, and the check valve 17 shown in FIG. When incorporated in the passage 13, the inflow port 46 is installed toward the water supply side, and the outflow port 47 is installed toward the hot water supply heat exchanger 3.

The inflow port 4 is provided inside the composite pipe 45.
A flow passage 48 is formed to connect and connect the outlet 6 to the outlet 6. A check valve seat 50 is provided on the inner peripheral wall of the flow passage 48.
Is provided. In this embodiment, the check valve seat 50 is provided with the second valve body 50 which has entered the inside of the first pipe 43.
Is formed by a protruding portion formed at the upper end of the opening of the tubular body 44. A check valve element 51 that faces the check valve seat 50 and closes the valve seat 50 from the outlet 47 side.
Is provided. This check valve element 51 has an outlet 4
A first overhang 51a overhanging toward the inflow port 46 and a second overhang 51b overhanging toward the inlet 46.
Are formed, and a shaft 52 is connected to the first overhang portion 51a.

Further, a locking portion 53 is formed on the inner wall portion of the flow passage 48 closer to the flow outlet 47 than the check valve seat 50, and a support plate 54a is formed on the locking portion 53. Locked. The support plate 54a is provided with a plurality of through holes (not shown) for communicating the flow passage 48 on the inlet 46 side of the support plate 54a with the flow passage 48 on the outlet 47 side of the support plate 54a. A through hole 54b through which the shaft 52 is inserted is formed in the central region, and a cylindrical wall portion 54c is formed to extend from an open end of the through hole 54b, and the cylindrical wall portion 54c and the through hole are formed. The shaft 52 is slidably inserted into and held by the cylindrical portion formed by the shaft 54b. The support 54a and the cylindrical wall 5
4c constitutes a support member 54 for holding the shaft 52 and supporting the check valve element 51.

A spring 55 is interposed between the support plate 54a of the support member 54 and the check valve element 51 in a compressed state, and the check valve is operated by the spring pressure of the spring 55. The body 51 is pressed against the check valve seat 50 to close the check valve seat 50. In this way, by closing the check valve seat 50 with the check valve element 51, it is possible to prevent the backflow from the outlet 47 side to the inlet 46 side. Further, when the water of the water supply source flows into the flow passage 48 through the inflow port 46, the water flow resists the spring pressure of the spring 55 and causes the check valve element 51 to act. The spring pressure and the like are set such that the flow path 48 is separated from the check valve seat 50 and the flow path 48 is in a water-permeable state.

The composite pipe 45, the check valve seat 50, the check valve 51, the shaft 52, the support member 54, and the spring 5
The portion 5 functions as a check valve for preventing the backflow of hot and cold water from the outlet 47 to the inlet 46.

Further, a drainage through hole 56 reaching the flow passage 48 is formed in the wall of the first tube 43, and a drainage plug 57 is inserted and mounted in the through hole 56. . By removing the drain plug 57, the flow path 4
The water in 8 can be drained.

FIG. 2 shows the check valve seat 50 and the shaft 52 shown in FIG. As described above, the check valve seat 50 is formed with the first overhang portion 51a overhanging on the outflow side and the second overhang portion 51b overhanging on the inflow side. The shaft 52 is connected to one overhang portion 51a.

As shown in FIG. 2, the first overhanging portion 51a is provided with an intake port 58 for taking in water into the inside of the check valve seat 50.
1b is provided with an outlet 60 for discharging the taken water,
A communication passage 61 that connects the intake port 58 and the outlet 60 is formed inside the check valve seat 50.

A protruding wall 62 is formed on the inner peripheral wall of the communication passage 61 so as to protrude therefrom.
A valve body 64 is provided in the communication passage 61 so as to face the valve seat 63 and close the valve seat 63 from the outlet 60 side. The valve body 64 has a movable member 64a formed of metal or the like, and a closing member 64b formed of an elastic material (for example, rubber) which is formed integrally with the movable member 64a and is capable of sealing the valve seat 63. And is configured. Outlet 60 of the communication passage 61
A spring engaging portion 65 is formed in the vicinity of the spring member 66. A spring 66 is interposed between the spring engaging portion 65 and the valve body 64 in a compressed state. The valve body 64 is pressed against the valve seat 63 to close the valve seat 63.

The valve seat 63, the valve body 64, and the spring locking portion 65
The spring and the spring 66 form an overpressure relief valve 68, and the overpressure relief valve 68 and the communication passage 61 constitute overpressure relief means.

The overpressure relief valve 68 is connected to the outlet side (hot water side).
Is higher than a predetermined pressure difference ΔP (for example, 2 kg / cm ² ) higher than the water pressure on the inlet side (water supply side), the water pressure on the outlet side resists the spring pressure of the spring 66. When the overpressure relief valve 68 is in the open state, the excessive water pressure is passed through the communication passage 61 when the overpressure relief valve 68 is open. The hot water side water pressure is released to the upstream side of the check valve 17 so as to reduce the water pressure to a value lower than the water pressure at which there is no risk of the occurrence of the water hammer and the operation of the hot water tap 39 can be avoided. .

The above set pressure difference ΔP is set to a value which is set so that the hot water pressure on the downstream side of the check valve 17 does not cause the occurrence of a water hammer and can prevent the operation of the hot water tap 39 from becoming difficult. This is a differential pressure for determining an appropriate overpressure relief valve opening timing for suppressing the pressure, and is obtained in advance by experiments, calculations, and the like.

The check valve 17 with an overpressure prevention function shown in this embodiment is configured as described above.
7 is incorporated in the water supply passage 13 of the combustion equipment as shown in FIG. 3, FIG. 4, or FIG. 5, for example, when hot water or hot water is being supplied, the reverse flow from the inflow port 46 shown in FIG. Water flows into the interior of the stop valve 17, and this water flow is generated by the spring 55.
Of the check valve element 51 against the spring pressure of the check valve seat 50
, The flow passage 48 is in a water-permeable state, and the water flowing into the check valve 17 is released by the check valve seat 50.
And flows out of the outlet 47 through the outlet port, and the discharged water is supplied to the hot water supply heat exchanger 3.

When no hot water or hot water is supplied, the water in the water supply passage 13 stays. In this state, the check valve 51 is reversed by the spring pressure of the spring 55. The stop valve seat 50 is closed to prevent backflow from the hot water supply heat exchanger 3.

Further, in the state where the check valve seat 50 is closed by the check valve element 51 as described above, the hot water pressure on the downstream side of the check valve 17 is increased on the upstream water supply side. When the pressure becomes higher than the water pressure by the set pressure ΔP or more, the pressure difference between the upstream side and the downstream side of the check valve 17 causes the valve body 64 of the overpressure relief valve 68 to separate from the valve seat 63 and release the overpressure relief valve. 68 is opened, whereby the communication passage 61 inside the check valve seat 50 is in a water-flowing state, and the hot water pressure on the downstream side of the check valve 17 passes through the communication passage 61 on the upstream side. And the hot water side water pressure is suppressed to a water pressure at which there is no risk of a water hammer and the opening operation of the hot water tap 39 can be prevented from becoming difficult.

According to this embodiment, when the hot water pressure on the downstream side of the check valve 17 becomes higher than the water pressure on the upstream water supply side by a predetermined differential pressure ΔP or more, the overpressure relief valve 68 is used.
Is opened, the communication passage 61 is in a water-permeable state, and the check valve 17 is opened.
Is provided with a configuration in which excess water pressure on the downstream side is released to the upstream side through the communication passage 61. For example, in the case of a post-boiling or one-can-two-channel type as shown in FIG. Even if the accumulated water in the hot water supply heat exchanger 3 is heated to a high temperature and the hot water pressure on the downstream side of the check valve 17 rises, the excess hot water pressure is transmitted to the upstream side of the check valve 17 through the communication passage 61. Since the hot water can be released, the hot water side water pressure can be suppressed to a water pressure at which there is no risk of occurrence of a water hammer and the operation of the hot water tap 39 can be avoided. By this, at the time of hot water filling start and hot water supply start,
It is possible to prevent the occurrence of a water hammer due to the post-boiling or reheating alone operation, and to prevent the opening operation of the hot water tap 39 from becoming difficult.

Further, since the check valve 17 has built-in overpressure preventing means, it is not necessary to provide an overpressure preventing means separately from the check valve 17, that is, it is possible to increase the number of parts or to configure the piping of the combustion equipment. Avoiding the occurrence of the water hammer and the difficulty in operating the hot water tap 39 by escaping the excessive hot water pressure downstream of the check valve 17 to the upstream without changing the water pressure as described above. Becomes possible. Furthermore, as described above, an increase in the number of components can be suppressed, and since there is no need to change the pipe configuration, an increase in the price of the combustion equipment can be suppressed. Further, it is possible to prevent the manufacturing process of the combustion equipment from being complicated and increasing the labor.

Furthermore, since the overpressure preventing means is built in the check valve 17 as described above, there is no need to provide a space for parts dedicated to preventing overpressure, and it is possible to avoid an increase in the size of the combustion equipment.

Hereinafter, a second embodiment will be described. In this embodiment, the check valve 17 as shown in FIG.
One-tank two-channel bath water heater or check valve 1 as shown in FIG.
It is intended for combustion equipment such as a two-pipe two-channel water heater with a 7 or a single-function water heater with a check valve 17 as shown in FIG. 5. As shown by broken lines in FIG. 3, FIG. 4 and FIG.
And a bypass passage 70 for short-circuiting the upstream side and the downstream side, and an overpressure relief valve 71 provided in the bypass passage 70. In the description of this embodiment, since the configuration other than the bypass passage 70 and the overpressure relief valve 71 has been described above, the overlapping description will be omitted.

The bypass passage 70 and the overpressure relief valve 71
The overpressure relief means 71 is constituted by a valve seat (not shown) and a valve body for closing the valve seat by spring pressure.
When the hot water pressure on the downstream side is higher than the water pressure on the upstream side by a predetermined pressure difference ΔP (for example, 2 kg / cm ² ) or more, the valve body is separated from the valve seat by the pressure difference. The overpressure preventing means opens the overpressure relief valve 71 when the hot water pressure becomes higher than the supply water pressure by the set pressure difference ΔP or more. The water pressure is released to the upstream side through the bypass passage 70, and there is no fear that the hot water pressure is generated by the water hammer.
The configuration is such that the water pressure can be suppressed to a level that can prevent the opening operation of the nozzle from becoming difficult.

The passage diameter of the bypass passage 70 is formed to be much smaller than the passage diameter of the water supply passage 13, and the passage resistance of the bypass passage 70 is much larger than the passage resistance of the water supply passage 13. This allows
Backflow of the water supply passage 13 is prevented.

According to this embodiment, when the hot water pressure on the downstream side of the check valve 17 becomes higher than the water pressure on the upstream side by a set pressure difference or more, the excess water pressure on the check valve 17 is used. Since the overpressure preventing means that escapes to the upstream side is provided, when the hot water side water pressure rises due to after-boiling or in the single-can, two-channel type combustion apparatus shown in FIG. Excessive hot-water pressure is checked by the check valve 17
Can be released to the upstream side of the hot water, so that the water pressure on the hot water side can be suppressed to a water pressure at which there is no danger of occurrence of a water hammer and the opening operation of the hot water tap 39 can be prevented from becoming difficult. It is possible to reliably prevent the opening operation of the hot-water tap 39 from becoming difficult at the time of or at the start of hot water supply, and to prevent the occurrence of a water hammer.

Hereinafter, a third embodiment will be described. The combustion apparatus of this embodiment is provided with a control structure for keeping the temperature of the hot water staying in the hot water supply heat exchanger 3 while the hot water supply is stopped. The other configurations are the same as those of the above-described embodiments, and the description thereof will not be repeated.

In this embodiment, the control device 40 is provided with a hot water retention control section (not shown) in the hot water supply heat exchanger. The hot water retention control section in the hot water supply heat exchanger controls the combustion of the burner as a heating means in accordance with a predetermined control procedure for keeping the hot water retained in the hot water supply heat exchanger 3 while the hot water supply is stopped. The control operation of the hot water retention control unit in the hot water supply heat exchanger makes it possible to supply hot water at a predetermined hot water supply set temperature immediately after hot water supply is started. is there.

There are various control procedures applied to the hot water keeping control section in the hot water supply heat exchanger. Here, the control operation may be performed in accordance with any of these control procedures. Will be described.

For example, a hot water temperature detecting means for detecting the temperature of hot water in the hot water supply heat exchanger 3 is provided, and an on-temperature Ton and an off-temperature Toff higher than the on-temperature Ton are given in advance to stop hot water supply. If it is detected during the hot water supply heat exchanger 3 that the temperature of the stagnant hot water in the hot water supply heat exchanger 3 is lower than the on-temperature Ton, the hot water in the hot water supply heat exchanger 3 is detected. It is determined that it takes a long time before the hot water of the hot water set temperature desired by the user of the hot water is supplied after the temperature is lowered and the hot water is started due to the low water temperature, and immediately after the hot water is started. It determines that it is necessary to heat the stagnant hot water in the hot water supply heat exchanger 3 so that hot water at the hot water set temperature can be supplied, and starts burning the burner.

The temperature of the stagnant hot water in the hot water supply heat exchanger 3 rises due to the burner combustion. During the burner combustion while the hot water supply is stopped, the hot water supply heat is determined based on the temperature detected by the hot water temperature detection means. When detecting that the temperature of the retained hot water in the exchanger 3 has reached the off-temperature Toff,
Stop burner combustion.

The stoppage of the burner combustion causes the temperature of the hot water in the hot water supply heat exchanger 3 to drop, and the temperature of the hot water in the hot water supply heat exchanger 3 decreases based on the temperature detected by the hot water temperature detecting means. When it is detected that the temperature has fallen below the ON temperature Ton, the burner combustion is restarted in order to prevent the temperature of the hot water staying in the hot water supply heat exchanger 3 from lowering.

As described above, the intermittent combustion of the burner is performed during the stop of the hot water supply operation, whereby the hot water staying in the hot water supply heat exchanger 3 can be kept warm. Immediately thereafter, hot water at the hot water supply set temperature can be supplied.

According to this embodiment, the hot water heat retention control section in the hot water supply heat exchanger is provided, and the hot water supply heat exchanger 3 is controlled by the burner combustion control by the heat retention control section while the hot water supply is stopped.
Since the configuration for keeping the hot water staying in the hot water is provided, the hot water at the hot water set temperature can be supplied immediately after the hot water supply is started,
Comfortable use of hot water can be provided.

However, as described above, the one-tank two-channel water heater with check valve 17 shown in FIG. 3 or the check valve 17 shown in FIG.
In a hot water heater with a check valve, such as a two-tank two-channel water heater or a single-function water heater with a check valve 17 shown in FIG. Is provided, while the hot water supply is stopped, the stagnant hot water in the hot water supply heat exchanger 3 is heated and expands in volume, and as described above, the hot water pressure becomes considerably high, and when the hot water supply starts, etc. This causes a problem that a water hammer is generated and a problem that it is difficult to open the hot water tap 39 and cannot be easily opened.

For example, when the power of the combustion equipment is turned off, the accumulated hot water in the hot water supply heat exchanger 3 is cooled without keeping the temperature of the accumulated hot water in the hot water supply heat exchanger 3.
When the power of the combustion equipment is turned on and the warming operation of the retained hot water in the hot water supply heat exchanger 3 is started, the accumulated hot water in the hot water supply heat exchanger 3 is heated and expanded in volume.
Hot water pressure will be quite high. In particular, when the power of the combustion equipment is turned on in the morning of winter, and then the accumulated hot water in the hot water supply heat exchanger 3 is heated by the operation of retaining the hot water in the hot water supply heat exchanger 3, the hot water pressure becomes higher. Rise to very high pressure,
As a result, the hot water tap 39 cannot be easily opened. In particular, when the hot water tap 39 is a mixing faucet 75 with a temporary stoppage as shown in FIG. 6, it is very difficult to open the mixing faucet 75 with a temporary stoppage. In addition, when the hot water tap 39 is opened, the probability of generating a very large water hammer becomes very high.

On the other hand, in this embodiment, since the overpressure preventing function as shown in the first or second embodiment is provided, the stagnation in the hot water supply heat exchanger 3 as described above is provided. Even in the case where the hot water retention control structure is provided, it is possible to reliably prevent the hot water pressure from becoming excessive, to prevent the operation of the hot water tap 39 from becoming difficult, and to provide a water hammer. The water pressure on the hot water side can be suppressed to a water pressure that can prevent the occurrence of water.

The present invention is not limited to the above embodiments, but may take various embodiments. For example, in the second embodiment, the overpressure relief valve 71 is configured to open using a pressure difference between the water pressure on the downstream side of the check valve 17 and the water pressure on the upstream side. However, for example, the overpressure relief valve 71 may be constituted by an electromagnetic valve or the like. In this case, for example, a differential pressure detecting means for detecting a differential pressure between the water pressure on the downstream side of the check valve 17 and the water pressure on the upstream side is provided, and the downstream of the check valve 17 is detected based on the differential pressure detecting means. The hot water pressure on the water side is a predetermined pressure difference Δ
The control device 40 is provided with a valve opening control unit that opens the solenoid valve (overpressure relief valve 71) when detecting that the pressure has become higher than P.

In the third embodiment, the hot water retention control unit in the hot water supply heat exchanger performs intermittent combustion of the burner to stop the hot water in the hot water supply heat exchanger 3 during the stop of the hot water supply. For example, a hot-water exchange temperature detecting means for detecting the temperature of the hot water in the hot-water supply heat exchanger 3 is provided, and the on-temperature Ton is given in advance to control the hot water retention in the hot-water supply heat exchanger. The unit detects burner combustion when the temperature of the stagnant hot water in the hot water supply heat exchanger 3 drops below the on-temperature Ton based on the detected hot water temperature of the hot-water hot water temperature detecting means while the hot water supply is stopped. Start, and after the start of combustion, the burner is continuously burned with a predetermined heat quantity for heat retention,
A configuration for keeping the hot water in the hot water supply heat exchanger 3 warm may be provided.

Further, in each of the above embodiments, a one-can, two-channel type bath water heater shown in FIG. 3, a two-pipe, two-channel type bath water heater / combiner shown in FIG. However, the combustion equipment of the present invention can be applied to any combustion equipment in which a check device is provided in a water supply passage for supplying water to a hot water supply heat exchanger. For example, a combustion device having a hot water supply function and other functions other than a hot water supply function such as a heating function, and a one-can three-water channel type combustion device having a hot water supply function, a bath function, and a heating function, such as a one-can double water channel. The combustion device of the present invention can be applied to a type of combustion device and the like. Further, the combustion device of the present invention can be applied to a combustion device for burning fuel other than fuel gas such as petroleum.

The non-return device with an overpressure prevention function according to the present invention includes a single-can double-channel combustion device as described above,
It can also be incorporated in a combustion device having a hot water supply function and a heating function, a combustion device of a type that burns fuel other than fuel gas such as petroleum, and the like.

[0085]

According to the combustion equipment of the present invention, when the hot water pressure on the downstream side of the non-return device becomes higher than the water pressure on the upstream water supply side by a predetermined pressure difference or more, the downstream side of the non-return device is checked. When the above-mentioned hot water pressure becomes higher than the feed water pressure by a predetermined pressure difference or more, the excessive hot water pressure becomes upstream of the check device. Side, and the hot water side water pressure can be suppressed from becoming a high pressure at which there is a risk of occurrence of a water hammer, and the occurrence of a water hammer at the start of hot water supply or at the start of hot water filling can be avoided. it can.

Further, since the hot water pressure can be suppressed from becoming high as described above, it becomes difficult to open the hot water tap provided on the hot water supply side of the hot water supply heat exchanger. It is also possible to avoid the problem caused by the high pressure.

In particular, in a configuration in which unheated water is mixed with hot water supplied by a hot water heat exchanger and discharged from a combustion device, the mixed hot water can be supplied to a hot water supply location. However, when the hot water pressure becomes high, the operation of opening the hot water tap becomes very difficult, which is a serious problem. However, as described above, it is suppressed that the hot water pressure becomes high. By doing so, it is possible to reliably prevent the problem of the opening operation of the hot water tap,
Very effective.

In the case of a single can double channel type combustion device,
Hot water remaining in the hot water supply heat exchanger is likely to be heated to a high temperature close to boiling due to the standalone operation of other functions other than hot water supply.
The volume expansion of the retained hot water is large and the hot water pressure often rises to a very high pressure. Difficult problems easily occur,
By providing the overpressure prevention means, it is possible to easily avoid the problem caused by the increase of the hot water side water pressure.

In the apparatus provided with the function of keeping the temperature of the hot water staying in the hot water supply heat exchanger during the stop of hot water supply, the hot water staying in the hot water supply heat exchanger is heated during the stop of the hot water supply, and Since the water pressure rises to a high pressure, the above-described overpressure prevention means is provided, although the problem of water hammer generation due to abrupt pressure fluctuation at the start of hot water supply and the problem of difficulty in opening the hot water tap easily occur. By this, it is possible to easily avoid the problem caused by the increase of the hot water pressure, and to provide a function for keeping the temperature of the hot water staying in the hot water heat exchanger during hot water supply stop. In addition, it is possible to provide a combustion apparatus capable of suppressing a problem of occurrence of a water hammer due to a sudden pressure change at the time of starting hot water supply and a problem of difficulty in opening a hot water tap.

In the apparatus having a check device with an overpressure prevention function having built-in overpressure prevention means, it is not necessary to provide an overpressure prevention means separate from the check device. To prevent the occurrence of problems caused by the increase in hot water pressure, to prevent the occurrence of new problems such as an increase in the number of parts of the combustion equipment and an increase in the work of assembling the combustion equipment, It is possible to avoid a problem caused by the increase of the hot water pressure during the stop of hot water supply. Also,
Since there is no need to provide a component dedicated to overpressure prevention, it is not necessary to provide a space for accommodating a component dedicated to overpressure prevention, and it is possible to prevent an increase in size of the combustion equipment. Further, as described above, an increase in the number of parts and a complicated assembly operation can be avoided, so that an increase in the price of the combustion equipment can be suppressed.

In the non-return device with overpressure prevention function, it is possible to prevent the backflow of hot water from the hot water supply heat exchanger side only by incorporating the non-return device with overpressure prevention function into the water supply passage of the combustion equipment. Of course, when the water pressure on the downstream side of the check device is higher than the water pressure on the upstream side by a predetermined differential pressure or more, the excess water pressure on the downstream side is released to the upstream side from the check device. Therefore, it is possible to reliably prevent the occurrence of a problem caused by a rise in the hot water pressure on the downstream side of the check device.

Further, as described above, it is possible to prevent the problem caused by the overpressure on the upstream side of the check device only by incorporating the check device with the overpressure prevention function according to the present invention into the combustion equipment. Therefore, it is not necessary to provide a dedicated component for overpressure prevention in the combustion equipment, and it is possible to eliminate the trouble of incorporating the dedicated component for overpressure prevention.By adopting the check device with overpressure prevention function of the present invention, In addition, it is possible to achieve an effect that it is possible to reduce the price of the combustion equipment, it is possible to avoid complication of the pipe configuration of the combustion equipment, and it is possible to prevent the combustion equipment from becoming large. .

[Brief description of the drawings]

FIG. 1 is a model diagram showing, by a cross section, an example of a check device having an overpressure prevention function which is characteristic in the first embodiment.

FIG. 2 is a model diagram showing a valve body portion shown in FIG.

FIG. 3 is a model diagram showing an example of a one-can-two-water-channel type combustion device.

FIG. 4 is a model diagram showing an example of a two-pipe two-water channel type combustion device.

FIG. 5 is a model diagram showing an example of a combustion device having a single function of hot water supply.

FIG. 6 is a model diagram showing an example of a system configuration of a mixing faucet with temporary stoppage.

[Explanation of symbols]

 REFERENCE SIGNS LIST 3 hot water supply heat exchanger 4 reheating heat exchanger 13 water supply passage 17 check valve 46 inflow port 47 outflow port 48 flow passage 50 check valve seat 51 check valve element 55 spring 61 communication passage 63 valve seat 64 Valve 68 Overpressure relief valve 70 Bypass passage 71 Overpressure relief valve 75 Mixing faucet with temporary stoppage

Claims (7)

[Claims] 1. A hot water supply heat exchanger for heating water supplied from a water supply passage to supply hot water, and a check device provided in the water supply passage for preventing a flow of hot water flowing backward from the hot water supply heat exchanger side. A combustion device, wherein when the pressure difference between the upstream water pressure on the upstream side of the check device and the hot water pressure on the downstream side of the check device is equal to or higher than a predetermined pressure difference, Combustion equipment provided with overpressure prevention means for releasing excess water pressure on the downstream side to the upstream side. 2. The non-return device is provided with an inlet for taking in water, an outlet for flowing out the taken water, and a flow passage communicating between the inlet and the outlet. A check valve seat is provided on an inner peripheral wall portion of the flow passage, and a check valve body is provided opposite to the check valve seat and closing the valve seat from the outlet side by spring pressure. A communication passage is formed inside the check valve body for communicating a flow passage on the inlet side with respect to the valve body and a flow passage on the outlet side with respect to the valve body. An over-pressure relief valve for allowing the communication passage to pass when the pressure difference between the upstream water supply pressure and the downstream hot water pressure is equal to or higher than a predetermined pressure difference. An overpressure preventing means is formed by the pressure relief valve and the communication passage, and the check device has a configuration incorporating the overpressure preventing means. The combustion device according to claim 1, wherein: 3. A bypass passage for short-circuiting the upstream side and the downstream side of the check device, and the overpressure prevention means is constituted by an overpressure relief valve provided in the bypass passage. Is opened when the pressure difference between the upstream water pressure on the upstream side of the check device and the hot water pressure on the downstream side is equal to or higher than the predetermined pressure difference, and the excess water pressure downstream of the check device is bypassed. 2. The combustion apparatus according to claim 1, wherein the combustion apparatus is configured to escape to an upstream side through the passage. 4. A heat exchanger having another function for performing functions other than hot water supply is provided integrally with the heat exchanger for hot water supply, and the integrated heat exchanger for hot water supply and the heat exchanger for other functions are heated in common. The combustion device according to claim 1, wherein the combustion device is a single-can, double-channel type combustion device provided with a burner. 5. A heating means for heating the hot water supply heat exchanger, wherein the driving control of the heating means is performed according to a predetermined control procedure for keeping the hot water staying in the hot water supply heat exchanger while the hot water supply is stopped. The combustion apparatus according to any one of claims 1 to 4, further comprising a hot water retention control section in the hot water supply heat exchanger for performing the following. 6. A configuration in which unheated water is mixed with hot water supplied by a hot water supply heat exchanger and flowing out of a combustion device, and the mixed hot water is supplied to a hot water supply location can be used. The combustion device according to any one of claims 1 to 5, characterized in that: 7. A non-return device with an overpressure prevention function for a combustion device, which is provided in a water supply passage for supplying water to a hot water supply heat exchanger of the combustion device and prevents a flow of hot water flowing backward from the hot water supply heat exchanger side. There is provided an inlet for taking in water, an outlet for taking out the taken water, and a flow passage communicating between the inlet and the outlet, and an inner peripheral wall portion of the flow passage is provided. Is provided with a non-return valve seat, and a non-return valve body which is opposed to the non-return valve seat and closes the valve seat from the outflow side by spring pressure is provided. A communication passage is formed in the inside of the valve body for communication between the flow passage on the inlet side of the valve body and the flow passage on the outlet side of the valve body. When the pressure difference between the upstream water pressure and the downstream water pressure is equal to or higher than a predetermined pressure difference, the communication passage is brought into the water passing state. Overpressure relief valve is provided,
The non-return valve body closes the non-return valve seat to prevent the flow of hot water flowing backward from the hot water supply heat exchanger side, and the differential pressure between the water pressure on the upstream side and the water pressure on the downstream side of the non-return device. When the pressure difference is equal to or greater than a predetermined differential pressure, the overpressure relief valve allows the communication passage to be in a water-permeable state, and excess water pressure downstream of the check device is released to the upstream side through the inside of the check device. Check device with overpressure prevention function.