JP2003343751A - Back-flow preventive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems of a conventional back-flow preventive device that the maintenance work is very complicated because a single part is directly assembled in a valve box and the whole product should be detached from piping, and that the function cannot be combined with other functions. <P>SOLUTION: A function part of the back-flow preventive device is a unit 1. The unit 1 is inserted into a storage chamber 28 of the valve box 2 having the storage chamber 28 for storing the unit 1 between a primary side channel 26 and a secondary side channel 27, and pressed/fixed with a lid 32 to make the back-flow preventive device. The unit 1 can be detached alone so that the performance can be confirmed and guaranteed by the unit 1. Accordingly, the maintenance work can be performed by taking out the unit 1 only from the valve box to be inspected or replaced, and further, combination of other functions is possible by assembling the unit 1 to the valve box 2 with other functions. <P>COPYRIGHT: (C)2004,JPO

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 for preventing backflow of a flow flowing from upstream to downstream. Particularly, the present invention relates to a backflow prevention device used when connecting a circuit of clean water and a circuit of miscellaneous water.

[0002]

2. Description of the Related Art Conventionally, parts have been individually assembled into a valve box for commercialization. Therefore, if an abnormality occurs, individual parts can be replaced, but the performance after replacement may change due to variations in parts, so the same inspection as during assembly is required.
We couldn't repair it on site. In addition, when the individual parts are assembled, it is difficult to combine them with other functions because the assembly and inspection are complicated.

[0003]

The backflow prevention device provided in the circuit connecting the tap water and the miscellaneous water is an important valve for preventing contamination of tap water, and reliably prevents the backflow and always maintains a normal state. It is an important requirement that maintenance and inspection be performed easily. It is an object of the present invention to provide a backflow prevention device that can be easily maintained and inspected, and to combine it with other functions to reduce the size of the system.

[0004]

In order to solve the above problems, in the first invention, an intermediate chamber is formed between the primary side flow passage and the secondary side flow passage, and the primary side flow passage and the intermediate side chamber are formed. A diaphragm is provided between the chambers, a DP flow path that connects the primary side flow path and the intermediate chamber is opened at the axial center of the diaphragm, and the DP flow path is opened and closed to allow the flow from the primary side flow path to the intermediate chamber. A first check valve that allows the flow to flow from the intermediate chamber to the primary side flow passage is installed, and an opening hole that opens to the atmosphere is opened at the bottom of the intermediate chamber to work with the first check valve. In the backflow prevention device, which is provided with a relief valve that opens and closes the opening hole, and drives the opening and closing of the first check valve and the relief valve by the movement of the diaphragm due to the pressure difference between the pressure in the primary side flow path and the intermediate chamber, As a unit, a mechanical unit consisting of a stop valve, a relief valve, a diaphragm and members associated with them A backflow prevention device comprising the unit installed in a storage chamber of a valve box in which a storage chamber for the unit is provided between the passage, the secondary flow passage, and the primary flow passage and the secondary flow passage. Since the unit is a unit, the performance is confirmed and the performance is guaranteed by the unit, and maintenance inspection can be performed by replacing the unit without removing the valve box.

In the second invention, an intermediate chamber is formed between the primary side flow passage and the secondary side flow passage, a diaphragm is provided between the primary side flow passage and the intermediate chamber, and the axial center portion of the diaphragm is provided. A DP flow path that connects the primary side flow path and the intermediate chamber is established in
A first check valve is installed that opens and closes the flow passage to allow flow from the primary flow passage to the intermediate chamber and blocks flow from the intermediate chamber to the primary flow passage, and opens to the atmosphere at the bottom of the intermediate chamber. A release valve that opens and closes the opening hole that interlocks with the first check valve, and the first check is performed by the movement of the diaphragm due to the pressure difference between the pressure in the primary side flow passage and the intermediate chamber. In a backflow prevention device that drives the valve and relief valve to open and close, a diaphragm mounting part is formed on the upper end surface, a discharge port is opened at the bottom axial center part, and a secondary side flow path is formed on the case side wall above the discharge port. A relief valve, a first check valve, a diaphragm, and a member associated with the relief valve configured to open and close the discharge port in a bowl-shaped case having a communication port formed therein are assembled as a unit by attaching the diaphragm to the diaphragm mounting portion. , The primary side flow path, the secondary side flow path and the primary side A storage chamber for the unit is provided between the channel and the secondary side flow passage, and the unit is placed in the storage chamber of the valve box having an opening hole that opens to the atmosphere at the bottom of the storage chamber. This is a backflow prevention device that is made watertight and is installed by partitioning the primary side flow path and the storage chamber in a watertight manner.By configuring the unit in a bowl-shaped case, it is possible to confirm the performance of the unit and ensure the performance guarantee. This facilitates maintenance and inspection, and makes it easy to integrate it into a valve box that has other functions.

A third aspect of the present invention is a secondary side from inside the unit at a communication port to a secondary side flow path of the unit, which has a mechanism portion composed of a first check valve, a relief valve, a diaphragm and members associated therewith as a unit. The backflow prevention device according to claim 1 or 2, further comprising a second check valve that allows a flow to the flow path and blocks a flow from the secondary side flow path into the unit. Since the second check valve for preventing the backflow from the secondary side into the unit is added to the communication port to the side flow passage, the maintenance and inspection of the backflow prevention device can be further simplified. In addition, it becomes easy to combine with other functions.

[0007]

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

FIG. 1 is a vertical cross-sectional view of a unit 1 in which a mechanism section composed of a first check valve 19, a relief valve 20, a diaphragm 5 and members associated therewith of the check valve is used as a unit, and FIG. 7 is a unit. It is a partial expanded longitudinal cross-sectional view of the case 4 of FIG. A discharge port 17 is formed at the bottom of the axis of the bowl-shaped case 4 having a diaphragm mounting portion 18 at the opening end, and a relief valve seat 11 surrounding the discharge port 17 is formed. The communication port 16 communicating with the next side is opened. Between the communication port 16 and the diaphragm mounting portion 18, a spring seat 21 of the DP urging spring 13 for urging the diaphragm 5 in the primary side direction and a stopper 22 for preventing the diaphragm 5 from moving are provided.

The diaphragm 5 has a through hole 23 through which the valve shaft 24 is inserted in the axial center thereof, and the diaphragm 5 is provided around the through hole 23.
A valve seat fitting 6 in which a check valve seat 9 surrounding the DP flow path 15 is provided on the primary side of the DP flow path 15 is integrally attached to the axial center of the diaphragm 5 in a watertight manner. The check valve body 10 is opposed to the check valve seat 9, and the check valve body 1 is provided.
0 is integrally mounted on the valve shaft 24 through the through hole 23 to mount the first check valve 19, and one end is suspended on the outer periphery of the valve shaft 24 by the valve seat metal fitting 6 so that the check spring 14 is installed. The relief valve body 12 is connected to the other end of the valve shaft 24 by being biased. Relief valve body 12 and valve shaft 2
4 is watertightly connected to the outside. The present embodiment is an example in which an O-ring is used to make a watertight connection.

Diaphragm 5 assembled as described above
The DP urging spring 13 is urged between the spring seat 21 of the case 4 and the valve seat fitting 6, and the relief valve body 12 is made to face the relief valve seat 11 to form the relief valve 20. The unit 1 is assembled by setting it on the diaphragm mounting portion 18 and by assembling the DP plate 8 in a watertight manner by caulking. The DP plate 8 protects the diaphragm 5 and may be omitted.

Next, FIG. 2 shows another embodiment of the unit 1 according to the present invention, and an enlarged view of the second check valve portion of the unit 1 is shown in FIG.
Shown in. Communication port 1 to the secondary side flow path 27 of the unit 1
6 is provided with a second check valve 25 that allows the flow from the inside (intermediate chamber) 42 of the unit to the secondary side flow passage 27 and blocks the flow from the inside of the secondary side flow passage 27 (intermediate chamber) 42. It was installed. A cylindrical rubber is fixed at one end to the outside (secondary side flow path side) of the case 4 so that the communication port 16 of the unit 1 is closed, and a convex ring 43 is provided at the inside of the other end. When the ring 43 is mounted in a state in which it is in close contact, the rubber expands due to the water pressure from inside the unit (intermediate chamber) 42, the ring 43 leaves the case 4, and the valve opens, and the water pressure from inside the unit (intermediate chamber) 42 disappears. With the elasticity of rubber, the ring 43 comes into close contact with the case 4 to close the valve and prevent backflow from the secondary side flow path. Others are the same as those of the unit 1 described above.

FIG. 3 shows how to assemble the above unit 1 into the valve box 2. Having a primary side flow passage 26 and a secondary side flow passage 27,
A storage chamber 28 having a mounting port for mounting the unit 1 is formed on the side surface of the valve box 2 upstream of the secondary flow path 27, and an opening hole 29 for opening the storage chamber 28 to the atmosphere is provided at the bottom of the storage chamber. At the same time, the primary side flow path 26 is provided in the storage chamber 28 of the valve box 2 which is opened in the same plane as the mounting port surface 35 of the storage chamber 28, and the above-mentioned unit 1 is provided as the discharge port 17 of the unit 1 as the opening hole 29 of the valve box 2. The packing 33 is attached in a watertight manner, the collar portion 34 of the unit 1 is attached to the jaw 36 of the storage chamber 28 together with the packing 30, and the attachment port surface 35 is attached to the jaw 31 by the lid 32 to be watertightly closed. The primary side 1 and the primary side flow path 26 are electrically connected and assembled. A second check valve 25 is attached to the secondary side flow passage 27 to prevent a reverse flow from the secondary side flow passage 27 to the storage chamber 28. An embodiment in which the assembly is completed is shown in FIG.

An embodiment in which another unit 1 is mounted is shown in FIG. A unit 1 in which a second check valve is installed in place of the unit 1 described above, and the second check valve 25 assembled in the secondary side flow passage 27 in the above-described embodiment is provided outside the case of the unit 1. It is the same as the above-mentioned embodiment except that it is installed.

Another embodiment according to the present invention is shown in FIG. Instead of the valve box described above, a primary chamber 37 having an insertion opening for the unit 1 and having continuity with the primary flow path 26 is provided on the primary side of the storage chamber 28 upstream of the secondary side flow path 27, and the unit is inserted from the insertion opening. 1 is attached to the discharge hole 17 of the unit 1 in a watertight manner in the opening hole 29 of the valve box 2 and is attached to the jaw portion 36 of the storage chamber 28 in a watertight manner while attaching the packing 30 to the collar portion 34 of the unit 1. Then, the unit holding metal fitting 38 is provided with the unit holding metal fitting 38 supported by the pillar 39 and the strainer 40 is attached around the pillar 39.
4 is pressed against the jaw 36 of the storage chamber 28 to seal the insertion opening in a watertight manner and assemble.

Another embodiment according to the present invention is shown in FIG. This is an example in which the unit 1 is incorporated into a valve box in which a water blocking mechanism 41 is provided in the primary side flow passage 26, as compared with the above-described embodiment. In this example, the water blocking mechanism 41 is incorporated in the primary side flow passage 26, but even in the case of a valve box provided with other mechanisms such as a solenoid valve and a pressure reducing valve, these are also the secondary side flow passage 27. However, there is no problem.

Next, the operation of the above-described embodiment will be described with reference to FIGS. When the water shut-off mechanism 41 is opened, running water flows from the primary side flow path 26 through the strainer 40 into the primary chamber 37, and pressurizes the diaphragm 5 of the unit 1. When the force of water pressure applied to the diaphragm 5 exceeds the force of the DP biasing spring 13 that biases the diaphragm 5, the diaphragm 5 moves downward together with the first check valve 19 and the relief valve body 12 assembled to the diaphragm 5. Move to and escape valve body 12
Is pressed against the valve seat 11 to close the relief valve 20. When the relief valve 20 is closed, the relief valve body 12 and the check valve body 10 connected to the relief valve body 12 cannot move. Therefore, the diaphragm 5 includes the DP urging spring 13 and the check valve body 10 in the diaphragm 5.
The first check valve 19 is opened by moving downward against the check spring 14 biased to the check valve seat 9. The flowing water enters the unit (intermediate chamber) 42 through the first check valve 19 and pushes open the second check valve 25 mounted on the case to open the secondary side flow passage 2
It reaches 7 and is supplied with water. (Figure 10)

When water is stopped on the secondary side, the differential pressure between the primary side flow path pressure and the secondary side pressure (intermediate chamber pressure) becomes small, the second check valve 25 closes, and the diaphragm 5 moves upward. The check valve body 9 is brought into pressure contact with the check valve body 10 to close and stop the first check valve 19, and the pressure difference in that state is maintained to prevent backflow. When the force that pressurizes the hydraulic diaphragm 5 in the primary side flow passage 26 decreases below the force of the DP biasing spring 13, valve leakage of the first check valve 19, breakage of the diaphragm 5 and the like occur, and the primary side flow passage 26 When the flowing water flows into the unit (intermediate chamber) 42, a valve leak occurs in the second check valve 25 and flows back into the unit (intermediate chamber) 42, etc. Primary side flow passage pressure and inside the unit (intermediate chamber) When the pressure difference from the pressure becomes smaller than that described above, the diaphragm 5 moves upward with the first check valve 19 closed and the relief valve body 12 of the relief valve 20 is pulled up to open the relief valve 20. The inside of the unit (intermediate chamber) 42 to the atmosphere, and the running water in the unit (intermediate chamber) 42, the running water from the primary side, and the backflowing water from the secondary side flow path are discharged to the atmosphere, and the primary side flow path Prevent backflow to 26. (Figure 9)

For maintenance and periodic inspection of troubles such as valve leakage of the check valve 19 as described above, the unit 32 is removed without removing the valve box 2 from the pipe and the unit 1 is taken out for inspection, repair or performance confirmation. By exchanging with and returning to the original.

When it is necessary to further ensure safety, the DP plate 8 is placed on a plate and the primary chamber 37 is sealed as in the embodiment of the unit shown in FIG. A third check valve seat 4 that opens a conduit 48 that connects the primary flow path 26 and the primary chamber 37 and surrounds the conduit 48 inside the DP plate 8
5 is formed, and the third check valve body 46 is provided on the upper surface of the check valve body 10.
Is installed to form the third check valve 47 by facing the third check valve seat 45, the above-mentioned trouble occurs, the relief valve 20 opens, and the running water is discharged to the outside. Also, when the pressure in the unit (intermediate chamber) rises and the diaphragm 5 rises, the third check valve 47 closes to shut off the primary chamber 37 and the primary side flow passage 26 and prevent the reverse flow to the primary side flow passage 26. You can also use it.

Further, the enlarged view of the relief valve portion of the embodiment of the unit shown in FIG. 12 shows the closing pressure of the relief valve 20 (first check valve 19).
It is possible to adjust the valve opening pressure) and make precise settings. When the distance between the relief valve body 12 and the check valve body 10 is changed, the urging force of the DP urging spring 13 changes and the relief valve 20
Since the valve closing pressure (opening pressure of the first check valve 19) changes, the relief valve body 12 or the check valve body 10 is made movable with respect to the valve shaft 24 by a screw or the like and is opposite to the relief valve body 12. Stop valve 1
By adjusting the distance of 0, the closing pressure of the relief valve 20 (opening pressure of the first check valve 19) can be set precisely. Figure 1
An enlarged view of the relief valve of the embodiment of the unit No. 3 is the check spring 14
As a check valve seat 50 provided on the valve rod 24 by changing one suspension to the relief valve body 12, the relief valve 20 eliminates the change in the biasing force of the check spring 14 when the relief valve body 12 is moved by adjustment. The pressure difference between the valve closing pressure and the valve opening pressure of the first check valve 19 can be adjusted without changing.

As described above, the backflow prevention device is constructed by inserting the main functional portion of the backflow prevention device as a unit into the storage chamber provided between the flow paths of the valve box and holding it by the lid. Periodic inspection and repair can be easily performed by removing the unit without removing the valve box from the pipe. In addition, when attempting to combine with other functions, it is sufficient to provide a storage chamber between the flow paths of the valve box with other functions, insert the unit and hold it down with the lid, and it will be possible to combine without any problems. I can. Further, according to the third invention, since the second check valve is assembled to the case of the unit, the maintenance and the combination can be further simplified. Further, the DP plate is used to seal the primary chamber, and a conduit for conducting the primary side flow passage and the primary chamber is provided in the axial center portion thereof, and the conduit is provided with a third check valve device which is interlocked with the first check valve. If installed, if the diaphragm moves upward even if the relief valve is opened, the third check valve closes to shut off the primary chamber and the primary side flow passage, and further reverse flow to the primary side flow passage. It can be prevented.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of a unit according to the present invention.

FIG. 2 is a longitudinal sectional view of another embodiment of the unit according to the present invention.

FIG. 3 is a vertical cross-sectional view showing how the unit according to the present invention is incorporated into a valve box.

FIG. 4 is a longitudinal sectional view of an embodiment of the backflow prevention device according to the present invention when there is no water pressure.

FIG. 5 is a longitudinal sectional view of another embodiment of the same device according to the present invention when there is no water pressure.

FIG. 6 is a vertical cross-sectional view of another embodiment of the same device according to the present invention when there is no water pressure.

FIG. 7 is a partially enlarged vertical sectional view of a case used in the unit according to the present invention.

FIG. 8 is an enlarged vertical sectional view of a second check valve portion of the unit according to the present invention.

FIG. 9 is a longitudinal sectional view of another embodiment of the same device according to the present invention when there is no water pressure.

FIG. 10 is a vertical cross-sectional view of the same embodiment when water is passed through.

FIG. 11 is a vertical sectional view of an embodiment in which a third check valve of the unit according to the present invention is installed.

FIG. 12 is an enlarged vertical sectional view of a relief valve portion of another embodiment of the unit according to the present invention.

FIG. 13 is an enlarged vertical sectional view of a relief valve portion of another embodiment of the unit according to the present invention.

[Explanation of Codes] 1-Unit 2--Valve box 3--
O-ring 4--Case 5--Diaphragm 6 ---
Valve seat metal fitting 7-O-ring 8-DP plate 9--
Check valve seat 10- Check valve body 11- Relief valve seat 12-
-Relief valve body 13-DP biasing spring 14--Check spring 15-
-DP flow path 16--Communication port 17--Discharge port 19-
-Check valve 20 --- Relief valve 24--Valve shaft 25-
-Second check valve 26--Primary-side flow path 27--Secondary-side flow path 28-
-Storing room 29--Opening hole 32--Lid 37-
-Primary chamber 41 --- Water stop mechanism 42 --- Intermediate chamber 44-
-Fixing part 45--Third check valve seat 46--Third check valve body 47-
-Third check valve 48--Conduit 49--Screw 50-
-Non-return spring seat

Claims (3)

[Claims] 1. An intermediate chamber is formed between a primary side flow passage and a secondary side flow passage, a diaphragm is provided between the primary side flow passage and the intermediate chamber, and a primary side is provided at an axial center portion of the diaphragm. A DP flow path that connects the flow path and the intermediate chamber is opened, and the DP flow path is opened and closed to allow a flow from the primary side flow path to the intermediate chamber and prevent a flow from the intermediate room to the primary side flow path. A check valve is installed, an opening hole that opens to the atmosphere is opened at the bottom of the intermediate chamber, and a relief valve that opens and closes the opening hole that interlocks with the first check valve is provided. In a backflow prevention device that drives the first check valve and the relief valve to open and close by the movement of the diaphragm due to the pressure difference in the chamber pressure, a mechanism section including a first check valve, a relief valve, a diaphragm, and a member associated therewith. As a unit, a primary side flow path, a secondary side flow path, and a unit between the primary side flow path and the secondary side flow path. Backflow prevention device in the storage chamber of the bets of the housing chamber provided with the valve body formed by mounting the unit. 2. An intermediate chamber is formed between the primary side flow passage and the secondary side flow passage, a diaphragm is provided between the primary side flow passage and the intermediate chamber, and the primary side is provided at the axial center of the diaphragm. A DP flow path that connects the flow path and the intermediate chamber is opened, and the DP flow path is opened and closed to allow a flow from the primary side flow path to the intermediate chamber and prevent a flow from the intermediate room to the primary side flow path. A check valve is installed, an opening hole that opens to the atmosphere is opened at the bottom of the intermediate chamber, and a relief valve that opens and closes the opening hole that interlocks with the first check valve is provided. In a backflow prevention device that drives the opening and closing of the first check valve and the relief valve by the movement of the diaphragm due to the pressure difference in the chamber, a diaphragm mounting part is formed on the upper end surface, and a discharge port is formed at the bottom axis part. In a bowl-shaped case that was opened and a communication port was established on the side wall of the case above the discharge port to communicate with the secondary flow path. A relief valve, a first check valve, a diaphragm and members associated therewith configured to open and close the discharge port are assembled as a unit by assembling the diaphragm into the diaphragm mounting portion, and the primary side flow path and the secondary side flow path are provided. And a storage chamber for the unit between the primary side flow path and the secondary side flow path,
At the bottom of the storage chamber, the unit is placed in the storage chamber of the valve box having an opening opening to the atmosphere and the discharge port of the unit is made watertight, and the primary side flow path and the storage chamber are made watertight by the case. Backflow prevention device that is equipped with partitions. 3. A communication port to a secondary side flow passage of a unit, which is a unit including a mechanism section composed of a first check valve, a relief valve, a diaphragm and members associated therewith, and from inside the unit to the secondary side flow passage. 3. The backflow prevention device according to claim 1 or 2, further comprising a second check valve that allows the flow of the second check valve and blocks the flow from the secondary side flow path into the unit.