JPH09329359A - Reverse flow prevention apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a reverse flow from the bathtub side to the water supply side by pouring water into a bathtub with service water pressure. SOLUTION: A discharge valve chamber 18 is provided on a hot water supply passage from a hot water heater to a bathtub. An upper chamber 46 and a lower chamber 47 of the discharge valve chamber 18 are communicated through a valve hole 50. An inlet of the valve hole 50 is closed with a negative pressure closing valve 51 by a spring 53, and an outlet side is closed with a discharge check valve 54 by a spring 55. A separation chamber 16 is provided upstream the upper chamber 46, and a main check valve 52 and an atmosphere release valve 27 are contained in the separation chamber 16. The main check valve 26 and the atmosphere release valve 27 are moved downward with hot water supply pressure to open a valve hole passage 24 and close a suction valve hole 41, and further open the negative pressure closing valve 51 and the discharge check valve 54 with the hot water supply pressure for pouring of water. Upon interruption of pouring water the main check valve 26 is moved upward with a spring 44 to close the valve hole passage 24 and open the valve hole 41, and further close the negative pressure closing valve 51 and the discharge check valve 54 whereby a reverse flow from a downstream side to an upstream side is prevented, and the inside of the separation chamber 16 is substituted for atmospheric pressure for separation between the upstream side and the downstream side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backflow prevention device provided in a hot water supply passage for dropping hot water of a water heater into a bathtub to prevent backflow from the bathtub side to the water heater side.

[0002]

As is well known, a hot water supply system for a bath is
The hot water supply pipe of the water heater is branched and one of them is connected to the reheating circulation pipe line of the bath kettle, and the hot water of the water heater is dropped into the bathtub through the branch pipe and the reheating circulation pipe line for automatic bath filling. In general, the hot water supply system of this bath is
A backflow prevention device is provided to prevent the water on the bath side from flowing back to the water heater side.

FIG. 4 shows a hot water supply system for a bath provided with a backflow prevention device. In the same figure, in the bathtub 1, a reheating circulation line 4 that sucks hot and cold water in the bathtub 1 with a circulation pump 2 and returns it to the bathtub 1 through a reheating heat exchanger 3
Is provided, and a hot water supply pipe 7 is provided on the side of the hot water supply device for heating the water supplied from the cold water pipe 5 by the hot water supply heat exchanger 6 and sending the hot water obtained by this heating to a desired location. . The hot water supply pipe 7 and the reheating circulation line 4 are connected to the solenoid valve 10
, A hopper 11 as a backflow prevention device, and a check valve 12 are connected, and when the bathtub 1 is filled with hot water, the hot water supply pipe 7
Then, the hot water is dropped into the bathtub 1 from the reheating circulation pipe 4 through the electromagnetic valve 10, the hopper 11, and the check valve 12 in this order. The hopper 11 completely cuts off the hot water supply pipe 7 and the reheating line 4 to completely block the hot water in the bathtub 1 from flowing back to the hot water supply pipe 7.

[0004]

However, since this former backflow prevention device is constituted by the hopper 11, when the hot water on the water heater side is supplied to the reheating circulation line 4 side, the solenoid valve 10 is used. Since the water pressure on the side is not directly applied to the pipe line on the side of the check valve 12, the speed of filling the water is slow, and it takes a long time to complete the filling.

The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to perform hot water filling using tap water pressure, and moreover, hot water on the bathtub side to the hot water supply pipe side. It is an object of the present invention to provide a backflow prevention device capable of completely preventing backflow.

[0006]

In order to achieve the above object, the present invention takes the following measures. That is,
A first aspect of the present invention is a backflow prevention device that prevents a backflow of a flow that flows from an upstream side to a downstream side, wherein the backflow prevention device includes a closing valve provided on the upstream side and a check valve provided on the downstream side. The closing valve provided on the upstream side is a negative pressure closing valve that is opened and closed by using the closing force set by the urging means and the opening force of the upstream hydraulic pressure. ing.

A second aspect of the present invention is a backflow prevention device which is provided in a hot water supply passage for dropping hot water from the water heater side into the bathtub to prevent backflow from the bathtub side to the water heater side. The hot water supply passage is provided with a discharge valve chamber, and the discharge valve chamber is divided into an upper chamber communicating with the upstream side of the hot water supply passage and a lower chamber communicating with the downstream side, and the upper chamber and the lower chamber are partition walls of the partition. A negative pressure shut-off valve that is communicated by a valve hole provided and is urged downward by a spring provided in the upper chamber to close the inlet of the valve hole is provided in the upper chamber. Is provided with a discharge check valve that is urged upward by a spring provided in the lower chamber to close the outlet of the valve hole.When hot water is supplied from the water heater side to the bathtub, the hot water supply pressure resists the urging force of the spring. Negative pressure stop valve and discharge check And a means for solving the problems with that it has a configuration in which the hot water supply water passage open press.

Further, a third aspect of the present invention is provided with the structure of the second aspect of the invention, wherein the upper chamber of the discharge valve chamber is connected to the upstream edging chamber, and the edging chamber has an upper side. A valve hole passage for introducing hot water from the water heater side, an intake valve hole communicating with the atmosphere on the bottom wall side, a passage communicating with the upper chamber of the discharge valve chamber is provided on the side wall side, A main check valve that opens and closes the outlet side of the valve hole passage, an atmosphere opening valve that opens and closes the intake valve hole, and the main check valve is biased upward to close the valve hole passage in the edge chamber. A spring is accommodated, the atmosphere release valve is connected to the lower side of the main check valve, and is vertically movable in conjunction with the main check valve. The main check valve is controlled by hot water supply pressure during hot water supply. By moving downward, the main check valve opens the valve hole passage and the air release valve sucks air. The valve hole is closed, and the main check valve is moved upward by the biasing force of the spring when hot water supply is stopped to close the valve hole passage by the main check valve and open the intake valve hole by the atmosphere opening valve. The opening of the valve hole replaces the rim cutting chamber with atmospheric pressure to eliminate the hot water supply pressure in the upper chamber of the discharge valve chamber and close the negative pressure stop valve, which is a means for solving the problem.

Further, in a fourth aspect of the invention having the structure of the third aspect of the invention, a drainage chamber for receiving water discharged from an intake valve hole of the edge cutting chamber is connected below the edge cutting chamber, This drain chamber is equipped with an overflow pipe to maintain the atmospheric pressure at all times.The drain chamber outputs a drain command when the water level in the drain chamber exceeds a set water level, and the drain from this water level switch. A means for solving the problem is provided by a structure provided with a drainage means for draining the water in the drainage chamber in response to the instruction.

Further, a fifth aspect of the invention is the third or fourth aspect of the invention.
According to the invention, the atmosphere release valve is held by the main check valve through a play gap of vertical relative movement, and the atmosphere release valve is formed with a pilot valve hole communicating with the atmosphere. A pilot valve that opens and closes the pilot valve hole is provided at the lower end side of the main check valve, and the pilot valve hole is closed by the downward movement of the main check valve, so that the play of the main check valve is reduced. The means for solving the problem is configured such that the pilot valve hole is opened by the pilot valve by the upward movement in the gap before the opening of the atmosphere opening valve.

In the present invention having the above-mentioned structure, when hot water is dropped into the bathtub from the water heater side, the hot water from the water heater side passes through the valve hole passage of the edging chamber to the main check valve by the hot water pressure. Press down to open the valve hole passage and allow hot water to enter the edging chamber. At this time, the atmosphere release valve is interlocked with the downward movement of the main check valve, so that the intake valve hole is closed by the atmosphere release valve and the pilot valve hole is closed by the pilot valve. Direct pressure is applied, and the system is ready to drop hot water from the water pressure.

The hot water that has entered the edging chamber enters the upper chamber of the discharge valve chamber, pushes up the negative pressure stop valve to open the inlet of the valve hole, and further pushes down the discharge check valve by the hot water supply pressure to open the outlet of the valve hole. Water is dropped into the open bathtub with water pressure.

When hot water supply to the bathtub is stopped, the main check valve moves upward within the play gap with the atmosphere opening valve due to the urging force of the spring in the edging chamber, and the pilot valve hole is opened by the pilot valve. Be seen. By opening the pilot valve hole, the atmosphere enters the edging chamber through the pilot valve hole, and the edging chamber is replaced with atmospheric pressure. After the rim-cutting chamber is replaced with atmospheric pressure, the intake valve hole is opened by the atmosphere opening valve by further upward movement of the main check valve.

Further, the pressure in the discharge valve chamber decreases due to the replacement of the atmospheric pressure in the rim cutting chamber by opening the pilot valve hole, and the pressing force of the negative pressure closing valve due to the urging force of the spring is the pressure in the rim cutting chamber (discharge valve chamber). The negative pressure shutoff valve moves upward by overcoming the pushing force of the negative pressure shutoff valve, and the inlet of the valve hole of the discharge valve chamber is closed, while the outlet of the valve hole is closed by the discharge check valve and the bathtub side. The backflow from the water heater to the water heater is prevented.

When the atmosphere opening valve is opened, the hot and cold water in the rim cutting chamber is discharged from the intake valve hole, but the discharged hot and cold water is received by the drainage chamber, and the water level in this drainage chamber exceeds the set water level. At this time, the drainage means is driven by the drainage command from the water level switch, and the hot and cold water in the drainage chamber is drained to the bathtub or the like.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. In the description of the present embodiment, the same parts as those of the conventional example are denoted by the same reference numerals, and detailed description thereof will be omitted. FIG. 1 shows an embodiment of a backflow prevention device according to the present invention in a system of an automatic bathtub, and FIG. 2 shows an enlarged detailed view of a valve mechanism portion of the backflow prevention device in the embodiment. It is shown. In these figures, the backflow prevention device includes a main valve chamber 15 and an edging chamber 16
A drainage chamber 17 and a discharge valve chamber (discharge side valve chamber) 18.

The inlet passage 20 of the main valve chamber 15 is connected to the hot water supply pipe 7 of the water heater 21 via the pipe 9 upstream of the hot water supply passage. A cylindrical wall functioning as a valve seat 23 projects from the upper wall (bottom wall of the main valve chamber 15) 22 of the edging chamber.
A pilot solenoid valve 25, which functions as a main opening / closing valve that opens / closes the inlet side of the valve hole passage 24, is arranged above 23.

The edging chamber 16 is provided below the main valve chamber 15, and the edging chamber 16 is provided with a first check valve 26 functioning as a main check valve and an atmosphere release valve 27. There is.

The first check valve 26 has a valve body 28 which is movable up and down along the inner wall surface of the edging chamber 16.
A seal member 30 such as an O-ring is mounted on the upper side of the valve member. The seal member 30 abuts against an inclined wall surface 31 provided on the outlet side of the valve hole passage 24, and the valve body 28 moves up and down. The outlet of the valve hole passage 24 is opened and closed. At the center of the valve body 28, there is provided a body portion 32 protruding downward, and a barrel member 34 having a flange 33 is loosely fitted in the body portion 32 so as to be vertically slidable. A pilot valve hole 36 is formed at the center of the bottom wall 35 of the member 34. The pilot valve hole 36 faces the lower end surface of the body 32 of the valve body 28,
A valve 37 functioning as a pilot valve is provided on the lower end surface, and the pilot valve hole 36 is opened and closed by the valve 37. Engaging piece from the peripheral wall side of the valve body 28
40 is projected toward the inside, and this engaging piece 40 is
As the 28 moves upward, it engages and holds the collar 33,
It is configured so that the tubular member 34 is pulled up in association with 28.

On the lower end surface side of the bottom wall 35 of the cylindrical member 34, a valve hole 41 as an intake valve hole that connects the edging chamber 16 and the drainage chamber 17 to each other.
A valve 42 for opening and closing the valve is provided, and the valve hole 41 is closed by the valve 42 due to the downward movement of the valve body 28.
As shown in FIG. 5, a gap 43 functioning as a play gap is formed between the engagement piece 40 and the collar 33. A spring 44 is disposed between the engagement piece 40 and the bottom wall of the edging chamber 16, and the valve body 28 is normally urged upward by the restoring force of the spring 44, and the outlet side of the valve hole passage 24. Is closed by the seal member 30, and the valve hole 41 is opened in this state. The cylinder member 34 and the valve 42 are integrated into the atmosphere release valve 27 that opens and closes the valve hole 41.
Is composed.

The discharge valve chamber 18 has an upper chamber 46 and a lower chamber 47 and is arranged adjacent to the edging chamber 16, and a passage 45 extending laterally from the edging chamber 16 connects the edging chamber 16 and the upper chamber 46. Communication is being pursued. A valve hole 50 is formed in the partition wall 48 of the upper chamber 46 and the lower chamber 47, and a negative pressure stop valve 51 is provided on the inlet side of the valve hole 50. The negative pressure stop valve 51 and the upper chamber 46
A compression spring 53 is interposed as a biasing means between the top walls 52, and the valve hole 50 is closed by a negative pressure stop valve 51 under the biasing force of the spring 53. On the other hand, the lower chamber 47 is provided with a second check valve 54 as a discharge check valve that opens and closes the outlet side of the valve hole 50.
A similarly compressed spring 55 is provided between 54 and the bottom of the lower chamber 47.
The second check valve 54 closes the outlet side of the valve hole 50 by the urging force of the spring 55. The lower chamber 47 is connected to the reheating line 4 via a filling tube 56 that forms the downstream side of the hot water supply passage.

A guide shaft 57 is projected upward from the bottom surface of the drainage chamber 17 communicating with the edging chamber 16 through the valve hole 41, and a float 58 is slidable on the guide shaft 57. It is fitted. A magnet (not shown) is attached to the float 58, and a reed switch (not shown) is provided on the wall surface of the drainage chamber 17, so that when the float 58 receives buoyancy and rises to a preset water level. , The magnet of the float 58 side and the reed switch face each other,
The reed switch outputs the ON signal of the drainage command that activates the circulation pump 2.
A water level switch is formed by the magnet on the 58 side and the reed switch. Further, an overflow pipe 60 protruding upward from the bottom wall side of the drainage chamber 17 is provided,
When the water level in the drainage chamber 17 exceeds the upper end of the overflow pipe 60, the overflow water (hot water) is discharged to the outside through the overflow pipe 60.

Further, the inlet side of the drainage pipe 61 is connected to the bottom wall of the drainage chamber 17, and the outlet side of the drainage pipe 61 is the return pipe 59 of the reheating circulation line 4, that is, the suction side of the circulation pump 2. Connected to the pipeline. The drain pipe 61 is provided with a third check valve 62 and a solenoid valve 63 that functions as a first control opening / closing valve. Further, an electric two-way valve 64 as a second control opening / closing valve is provided in the return pipe 59, which is closer to the bathtub 1 side than the outlet side connection portion of the drain pipe 61. In the figure, 65
Is a flow rate sensor, 66 is a water amount control valve, 67 is a water level sensor (pressure sensor) for detecting the water level in the bathtub 1 by pressure, and 68 is a reheating water switch for detecting the flow of reheating hot water.

The backflow prevention device of the present embodiment is constructed as described above, and its operation will be described below. First, when the inlet side of the valve hole passage 24 is opened by the opening operation of the pilot solenoid valve 25, the hot water supplied from the hot water supply pipe 7 enters the valve hole passage 24, and the water pressure causes the valve body 28 to spring.
It is pushed downward against the urging force of 44 to open the outlet side of the valve hole passage 24. At the same time, the pilot valve hole 36 is closed by the downward movement of the valve 37 by the downward pressing movement of the valve body 28, and the valve hole 41 is similarly closed by the downward movement of the valve 42,
The communication between the edging chamber 16 and the drainage chamber 17 is cut off. Due to this disconnection, the hot water entering the edging chamber 16 overcomes the urging force of the spring 53 by the water pressure, pushes up the negative pressure stop valve 51 and enters the valve hole 50, and further the second check valve 54 is attached to the spring 55. As a result of pressing down downward against the power and opening the outlet side of the valve hole 50, the hot water enters the lower chamber 47 through the valve hole 50, and further enters the reheating circulation line 4 through the hot water filling pipe 56 and The water is dropped into the bathtub 1 from both sides of the forward pipe 69 and the return pipe 59 of the burning circulation pipe by water pressure.

When the water level for filling the bathtub 1 reaches the set water level, the inlet side of the valve hole passage 24 is closed by the closing operation of the valve of the pilot solenoid valve 25, so that the valve body 28 is pressed downward. The upward biasing force of the spring 44 overcomes the force, and the valve body 28 starts to move upward. At this time,
As shown in FIG. 3, a gap 43 is formed between the flange 33 of the tubular member 34 on which the valve 42 is formed and the engagement piece 40 on the valve body 28 side. Upward movement until 40 is locked to the collar 33 (This upward movement is performed with the upper and lower sides of the first check valve under equal pressure in the edging chamber, so it is easily performed by the urging force of the spring 44. As a result of this upward movement of the valve body 28, the valve 37 also moves upward in conjunction therewith, so that the pilot valve hole 36 is opened first.

As a result, the atmosphere on the side of the drainage chamber 17 enters the edging chamber 16 through the pilot valve hole 36, resulting in the edging chamber.
16 is atmospheric pressure, and the valve 42 that uses the water pressure in the edging chamber 16
The closing force for pressing the valve hole 41 due to is released. When the valve body 28 continues to rise further due to the restoring force of the spring 44,
The engagement piece 40 engages with the flange 33, and the tubular member 34 moves upward integrally with the valve body 28. Therefore, the valve 42 also moves upward integrally, and the valve hole 41
Is completely opened, and the outlet side of the valve hole passage 24 is the first check valve.
It is closed by a sealing member 30 at 26. At this time, the hot water filled in the edging chamber enters the drain chamber 17 side through the valve hole 41. At this time, when the float 58 receives buoyancy and rises to the set position, an ON signal is output from the reed switch and the electromagnetic wave is output. Since the valve 63 is opened and the electric two-way valve 64 is closed to start the circulation pump 2, the water accumulated in the drainage chamber 17 passes through the drainage pipe 61 and is forcibly driven by the circulation pump 2. The water is discharged into the bathtub 1 from the outward pipe 69 side of the burning circulation line 4.

As described above, the pilot solenoid valve 25 is closed to move the first check valve 13 upward, and the pilot valve hole 36 is opened. As a result, air enters the edging chamber 16. When replaced by atmospheric pressure, the discharge valve chamber
When the pressure of the upper chamber 46 of 18 decreases and the biasing force of the spring 53 becomes larger than the upward pushing force of the negative pressure closing valve 51 due to the pressure of the upper chamber 46, the negative pressure closing valve 51 is driven by the spring 53. By moving downward, the inlet side of the valve hole 50 is closed to prevent air on the drain chamber 17 side from entering the valve hole 50 through the edging chamber 16. Further, the second check valve 54 also closes the outlet side of the valve hole 50 by the urging force of the spring 55 at the same time as the closing operation of the pilot solenoid valve 25, and the waste water is cut off from the reheating circulation line 3 side through the valve hole 50. Prevent entry into the room 16 side.

Thus, the inlet side of the valve hole 50 of the discharge valve chamber is closed by the negative pressure stop valve 51, and the outlet of the valve hole 50 is closed by the second check valve 54.
By closing the inlet and outlet of the valve hole 50 with a combination of the negative pressure stop valve 51 and the second check valve 54, the negative pressure stop valve 51 and the second check valve are closed. The valve 54 allows water to flow only when the pressure on the upstream side of the discharge valve chamber 18 is higher than the pressure on the downstream side. Therefore, with respect to the reverse flow from the downstream side to the upstream side that occurs only when the upstream side pressure is lower than the downstream side pressure, the second check valve prevents the reverse flow and the upstream side pressure is negative. In the case where the pressure is increased, the negative pressure closing valve 51 is pressed more strongly in the closing direction by the pressure of the negative pressure. Therefore, the negative pressure closing valve 51 cooperates with the second check valve to prevent the reverse flow. As a result, it is possible to reliably prevent the backflow that occurs when the upstream pressure of the discharge valve chamber becomes lower than the downstream pressure. In this case, even if sewage on the bathtub side flows back to the edge chamber due to a failure of the second check valve 54 and the negative pressure stop valve 51, the backflowed sewage is drained from the open valve 42 to the drainage chamber 17. Because it is done
It is possible to completely prevent the sewage on the downstream side from flowing back to the water heater side.

In the above embodiment, when the edging chamber 16 is opened to the atmosphere, first, the valve 37 is moved upward in conjunction with the upward movement of the valve body 28 to open the pilot valve hole 36, and the edging chamber 16 is enlarged. Since the engaging piece 40 and the flange 33 are engaged with each other to make the valve 42 move upward by opening the valve hole 41 after the pressure is changed to the atmospheric pressure, the valve hole 41 is opened by using the spring 44 having a small restoring force.
You can open 41. When the pilot valve hole 36 and the valve 37 are not provided, when the valve 42 is opened, the edging chamber 16 has a higher pressure than the drainage chamber 17, and therefore the valve 42 moves downward due to this pressure difference. Pressed valve hole 41
When the valve hole 41 is opened, a spring 44 having a strong restoring force that overcomes the pressure difference must be used.
When opening and filling water, there is a problem that the valve 42 is pushed down by using the water pressure of the hot water that has entered the valve hole passage 24 and the valve hole 41 cannot be closed, but as in the present embodiment example, By providing the pilot valve hole 36 and the valve 37, first opening the pilot valve hole 36 to eliminate the pressure difference, and then opening the valve hole 41, the restoring force of the spring 44 can be reduced. This allows the spring
It is possible to solve the problem caused by strengthening the restoring force of 44, and immediately press down the first check valve 13 to open the valve hole passage 24 and open the valve 37 even with a small amount of dropped hot water. By closing the pilot valve hole 36 and the valve hole 41 by the valve 42, it is possible to smoothly drop hot water by using the tap water pressure.

Further, as described above, since the restoring force of the spring 44 can be made small, the opening operation of the first check valve and the closing operation of the valve hole 41 can be performed quickly, so that the first check valve is provided. The time from when the valve 26 is opened to when the valve hole 41 is closed by the valve 42 can be shortened, and from the time when the valve hole passage 24 is opened by the first check valve 26 until the valve hole 41 is closed. Further, it is possible to obtain an effect that the amount of wasteful hot and cold water discharged from the valve hole 41 can be reduced.

Further, in the present embodiment, since the passage 45 that connects the edging chamber 16 and the upper chamber 46 of the discharge valve chamber 18 is provided below the outlet side closing surface of the valve hole passage 24, it is filled with water. When performing the above, the first check valve 26 can be easily pushed down by the water pressure. This passage 45 is connected to the first check valve 26.
If it is provided above the closing surface of, the stagnation part is generated on the upper side of the passage 45, the pressure in the passage 45 becomes high, and this pressure acts in the direction of closing the first check valve 26. When the pilot solenoid valve 25 is opened and the hot water on the side of the water heater enters the valve hole passage 24, the first check valve 2 due to the tap water pressure of the hot water.
6, that is, it is difficult to push the valve element 28 downward, but by providing the passage 45 below the closing surface of the first check valve 26 as in the present embodiment, the passage 45 There is no stagnation inside, and therefore, no force is generated from the passage 45 side in the direction of closing the first check valve 26. Therefore, when the water is filled, the first check valve 26 is easily lowered by the tap water pressure. It is possible to push it down, and it is possible to perform the filling operation smoothly.

Further, since the discharge valve chamber is provided with the negative pressure shutoff valve 51, when the pilot solenoid valve 25 is closed to stop the water flow of the hot water filling, the negative pressure shutoff valve 51 is closed to make the hot water filling. It is possible to prevent air from entering the pipe 56, and when the water level sensor 67 is provided in the water filling pipe 56, this water level sensor 67 causes the air in the water filling pipe 56 to cause It is possible to prevent the problem that the water level detection malfunctions.

Further, when the bathtub 1 is provided above the appliances (the water heater and the backflow prevention device), for example, when the appliances are provided on the first floor of the household and the bathtub 1 is installed on the second floor of the household. However, the second check valve 54 prevents sewage on the bathtub 1 side from entering the edging chamber 16 side, which is sanitary and safe. In this case, even if the first check valve 26 and the second check valve 54 fail and the wastewater on the bathtub 1 side enters the edging chamber 16 side, this sewage flows from the edging chamber 16 to the drainage chamber 17. When it enters and the float 58 rises to a predetermined water level, an ON signal is output from the reed switch, the circulation pump 2 is started, the electric two-way valve 64 is closed, and the solenoid valve 63 is opened. The sewage collected in 17 is forcibly returned by the circulation pump 2 to the bathtub 1 side through the forward pipe 69 of the reheating circulation line 4, and the sewage on the bathtub 1 side does not flow back to the water heater side. Further, in this case, even when the circulation pump 2 cannot be started due to a power failure or the like, when the water level of the wastewater accumulated in the drainage chamber 17 exceeds the upper end opening of the overflow pipe 60, it is discharged to the outside from the overflow pipe 60. In any case, the sewage side and the clean water side are surely cut off in the edging chamber 16, and the sewage on the bathtub 1 side is completely prevented from flowing back to the water heater side on the clean water side.

The present invention is not limited to the above embodiment, but various embodiments can be adopted.

[0035]

According to the present invention, a discharge valve chamber is provided in a hot water supply passage through which hot water is dropped from a water heater side to a bath, and an inlet of a valve hole provided in the discharge valve chamber is closed by a negative pressure stop valve, and an outlet is provided. Is configured to be closed by the discharge check valve, so the negative pressure stop valve and the discharge check valve can be opened and the water filling can be performed only when the pressure on the upstream side of the discharge valve chamber is higher than that on the downstream side. It becomes possible to do water. Therefore, when the pressure on the downstream side is higher than that on the upstream side and a backflow occurs from the downstream side to the upstream side, the backflow is prevented by closing the discharge check valve, and When a negative pressure phenomenon occurs on the upstream side where the pressure on the upstream side is lower than the pressure on the downstream side, the pressure due to the negative pressure pushes the negative pressure on-off valve more strongly in the closing direction, thus promoting backflow prevention. Therefore, due to the backflow prevention effect in cooperation with the discharge check valve, it is possible to reliably prevent the backflow from the bathtub side to the water heater side.

In this case, even if sewage on the bathtub side flows back to the edging chamber due to a failure of the discharge check valve and the negative pressure opening / closing valve, the sewage that has flowed back is discharged from the intake valve hole of the edging chamber. Therefore, it is possible to completely prevent the backflow filthy water from entering the water heater side, and the hygiene safety is outstanding.

Further, the main check valve and the atmosphere opening valve provided in the edging chamber are interlocked to close the valve hole passage by moving the main check valve upward when the hot water supply is stopped and open the intake valve hole by the atmosphere opening valve. With the configuration that interlocks,
When the hot water supply is stopped, the intake valve hole is opened,
The rim-cutting chamber can be replaced with atmospheric pressure.When replacing the rim-cutting chamber, the pressure in the upper chamber of the discharge check valve is lowered to close the negative pressure shut-off valve by the biasing force of the spring. When the chamber is replaced with atmospheric pressure, the negative pressure stop valve is closed to prevent air from entering the hot water supply passage downstream of the discharge valve chamber before the air entering the edging chamber enters the discharge valve chamber. This allows the problem that air enters the circulation pump on the downstream side of the discharge valve chamber, for example, in the circulation pump of the reheating circulation line to hinder the operation of the circulation pump, or on the downstream side of the discharge valve chamber. It is possible to prevent a problem that the provided water level sensor is affected by the mixing of air.

Further, in the structure in which the main check valve and the atmosphere release valve are connected through the play gap,
When closing the valve hole passage and opening the intake valve hole when hot water supply is stopped, first, the main check valve moves upward using the play gap to open the pilot valve hole by the pilot valve to the atmosphere. Since the valve is configured to open before opening the intake valve hole and after replacing the inside of the rim cutting chamber with atmospheric pressure, the atmosphere release valve is configured to open in conjunction with the upward movement of the main check valve. It is possible to reduce the restoring force of the spring that moves the check valve upwards, so that when the hot water is dropped into the bathtub side, the main check valve can be pushed down and moved reliably even with a small amount of hot water. By opening the valve hole passage and closing the intake valve hole, it is possible to smoothly fill the water with tap water pressure.

Moreover, as described above, the restoring force of the spring for urging the main check valve upward can be made small, so that the main check valve can be quickly pushed down and moved by the hot water supply pressure at the start of filling. Therefore, the time from the main check valve opening the valve hole passage until the atmosphere opening valve closes the intake valve hole can be shortened, and the amount of waste water discharged from the intake valve hole within that time can be shortened. Can be reduced.

Further, when the water level of the hot water accumulated in the drainage chamber exceeds the set water level, a drainage command is output by the water level switch and the drainage means drains the water in the drainage chamber. It is not necessary to perform the drainage operation every time the hot water is dropped into the water, and the drainage operation is performed only when the water level in the drainage chamber exceeds the set water level. The sequence operation can be shortened, and when the water level in the drainage chamber exceeds the set water level, the drainage operation is performed, so it is possible to prevent water from being drained from the drainage chamber to the floor surface through the overflow pipe. it can.

Further, since the overflow pipe is provided in the drainage chamber, if the water level in the drainage chamber reaches the inlet of the overflow pipe, the overflow pipe is used to discharge the drainage chamber to the outside at the same time. Since it is always kept at atmospheric pressure, the negative pressure stop valve can be reliably closed by opening the atmosphere release valve (or pilot valve hole), preventing backflow and the downstream passage of the negative pressure stop valve. It is possible to reliably prevent the problem that air enters into the.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a backflow prevention device according to the present invention in a system of an automatic bathtub.

FIG. 2 is a detailed explanatory diagram of a valve mechanism portion of the backflow prevention device according to the embodiment.

FIG. 3 is an explanatory diagram of an operating state of the atmosphere release valve during water flow in the embodiment.

FIG. 4 is an explanatory view showing a hot water supply device of a former bath by an automatic bath kettle system.

[Explanation of symbols]

 16 Edge cut chamber 17 Drainage chamber 18 Discharge valve chamber 26 First check valve (main check valve) 27 Atmosphere release valve 36 Pilot valve hole 37 Valve (pilot valve) 41 Valve hole (intake valve hole) 50 Valve hole 51 Negative Pressure stop valve 54 Second check valve (Discharge check valve)

Claims (5)

[Claims] 1. A backflow prevention device for preventing a backflow of a flow flowing from an upstream side to a downstream side, wherein the backflow prevention device comprises a closing valve provided on an upstream side and a check valve provided on a downstream side, The backflow prevention is characterized in that the shutoff valve provided on the upstream side is a negative pressure shutoff valve that is opened and closed by utilizing the valve closing force set by the biasing means and the valve opening force due to the upstream side water pressure. apparatus. 2. A backflow prevention device provided in a hot water supply passage for dropping hot water from the water heater side into the bathtub to prevent backflow from the bathtub side to the water heater side, wherein the backflow prevention device is provided in the hot water supply passage. The discharge valve chamber is divided into an upper chamber that communicates with the upstream side of the hot water supply passage and a lower chamber that communicates with the downstream side, and the upper chamber and the lower chamber are defined by the valve holes provided in the partition wall of the partition. A negative pressure stop valve is provided in the upper chamber, which is urged downward by a spring provided in the upper chamber to close the inlet of the valve hole, and the lower chamber is provided in the lower chamber. Is provided with a discharge check valve that is urged upward by a spring to close the outlet of the valve hole, and when hot water is supplied from the water heater side to the bathtub, the negative pressure stop valve is resisted by the spring water pressure against the spring urging force. And push the discharge check valve open to supply hot water. A backflow prevention device configured to perform water. 3. An upper chamber of the discharge valve chamber is connected to an upstream rimming chamber, and a valve hole passage for introducing hot water from the water heater side is provided on the upper side of the edging chamber, and a bottom wall side is provided on the bottom wall side. An intake valve hole communicating with the atmosphere is provided with a passage communicating with the upper chamber of the discharge valve chamber on the side wall side, and a main check valve for opening and closing the outlet side of the valve hole passage is provided in the rimming chamber. An atmosphere opening valve that opens and closes the intake valve hole and a spring that urges the main check valve upward to close the valve hole passage are housed, and the atmosphere opening valve is below the main check valve. It is connected to the main check valve so that it can move up and down freely.
When the main check valve moves downward due to the hot water supply pressure during hot water supply, the main check valve opens the valve hole passage and the atmosphere release valve closes the intake valve hole, and the main check by the spring bias when the hot water supply is stopped. By moving the valve upward, the main check valve closes the valve hole passage and the atmosphere opening valve opens the intake valve hole.By opening this intake valve hole, the rimming chamber is replaced with atmospheric pressure and the inside of the upper chamber of the discharge valve chamber is closed. The backflow prevention device according to claim 2, wherein the hot water supply pressure is released to close the negative pressure stop valve. 4. A drainage chamber for receiving water discharged from an intake valve hole of the edge-cutting chamber is connected below the edge-cutting chamber, and the drainage chamber is provided with an overflow pipe to constantly maintain atmospheric pressure. The chamber is provided with a water level switch that outputs a drainage command when the water level in the drainage chamber exceeds a set water level, and a drainage means that receives the drainage command from the water level switch and drains the water in the drainage chamber. Item 6. The backflow prevention device according to item 3. 5. The atmosphere release valve is held by a main check valve through a play gap of relative movement in the vertical direction, and a pilot valve hole communicating with the atmosphere is formed in the atmosphere release valve, and the main check valve of the main check valve is formed. A pilot valve for opening and closing the pilot valve hole is provided on the lower end side, and the pilot valve hole is closed by the downward movement of the main check valve, and the pilot check valve is opened above the play gap in the main check valve. The backflow prevention device according to claim 3 or 4, wherein the pilot valve hole is opened by the pilot valve by the movement before opening the atmosphere opening valve.