JPH05215259A - Backflow prevention device - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a backflow prevention device capable of preventing the generation of abnormal noise to the outside due to the vibration of a valve. [Structure] The present invention relates to a water inlet portion 1 of a backflow prevention device 100.
The passage shape of 05 is such that the opening area of the water inlet portion 105a is the largest and the opening area gradually decreases as it approaches the valve operation chamber 104, and the wall surface thereof has a smooth curved surface shape (bellmouth shape). is there. [Effect] In the backflow prevention device of the present invention, since the flow of water that has passed through the inlet portion and flowed into the valve operation chamber is a laminar flow, the valve is stationary at the position of the stopper due to the water pressure, so that the external vibration caused by vibration It is possible to prevent the generation of abnormal noise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backflow preventing device for preventing a backflow of a fluid or the like, and more particularly to a structure of the backflow preventing device.

[0002]

2. Description of the Related Art A conventional backflow prevention device is disclosed in Japanese Patent Application No. 3-11443.
Like the backflow prevention device of the water purifier described in No. 6,
In many cases, the shape of the fluid inlet of the backflow prevention device is such that the flow of the fluid changes rapidly at the inlet.
As a result, a turbulent flow is generated at the moment when the fluid flows into the chamber where the valve operates from the inlet, and the vortex generated by this turbulence causes vibration in the chamber where the valve operates and causes abnormal noise. there were.

[0003]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the prior art, the present invention has devised the shape of the fluid passage from the fluid inlet of the backflow prevention device to the chamber in which the valve operates.
This aims to prevent abnormal noise from the backflow prevention device.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a backflow preventive device in which the shape of a fluid passage from the fluid inlet portion to the chamber in which the valve operates is defined as follows. The opening area is the largest, the opening area gradually decreases, and the wall surface is a smooth curved surface so that the fluid does not become turbulent in the chamber where the valve operates.

[0005]

According to the present invention, the fluid flowing into the backflow preventer does not become turbulent as in the conventional case even when it passes through the fluid passage shape of the present invention and flows into the chamber in which the valve operates. Since it is a laminar flow, the valve rises due to the pressure of the fluid and stops at the position of the stopper due to the pressure of the fluid, so that abnormal noise due to the vibration of the valve can be prevented.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall block diagram of a backflow prevention device of the present invention. FIG. 2 is a structural diagram in which the backflow prevention device of FIG. 1 is incorporated in a water purifier. The overall configuration will be described with these.

An inlet 2 having a raw water inlet 1 is fixed to a base 3. The cartridge 4 is formed by a synthetic resin main body 6 having a purified water discharge port 5 at the top and a lid 8 having a raw water inlet 7, and a hollow fiber membrane 11 housed in a case 10 having activated carbon 9 and an opening as a filter medium. It is built in.

The hollow fiber membrane 11 is a bundle of threads having openings of about 0.1 μm.

In order to prevent the activated carbon 9 from flowing out, an inlet filter 20 and an outlet filter 12 are mounted.

The cartridge 4 is screwed into the inlet 2 and fixed to the base 3. A synthetic resin backflow prevention device 100 is attached to the purified water discharge port 5 and is sandwiched by the upper case 13. In the backflow prevention device 100, a part of the outer circumference forms a threaded portion 110, and the hose joint 1
4 is connected.

The inlet 2 is equipped with an inlet joint 15 into which raw water supplied from the water tap 50 flows in via a hose.

Next, the operation will be described with reference to FIGS. 1 and 2.

By opening the water tap 50 dedicated to the water purifier, the raw water of the tap water is sent to the one-way water tap 50, passes through the hose, and passes through the inlet joint 15 and the inlet 2.
It flows into the cartridge 4.

The activated carbon 9 in the cartridge 4 adsorbs the organic matter of the raw water and residual chlorine, and then the case 1 is opened through the opening.
It flows into 0. The hollow fiber membrane 11 housed in the case 10 removes foreign matters such as dust.

The water purified by these filter media passes through the purified water discharge port 5 and flows into the backflow prevention device 100 of the present invention held by the upper case 13. The water that has passed through the backflow prevention device 100 passes through the hose 51 connected to the hose joint 14, returns to the water tap 50, and is discharged to the outside from here.

Next, the structure and operation of the backflow prevention device 100 will be described with reference to FIGS.

As shown in FIG. 1, the backflow prevention device 100 includes a valve 101 made of silicone rubber for preventing backflow of discharged water, and a valve seat made of synthetic resin for closely contacting the valve 101 to prevent water from flowing out. 102, stopper 103 and valve 10 made of synthetic resin that prevent the valve 101 from popping out by water pressure
1 is composed of a synthetic resin valve operation chamber 104. Regarding the operation, the water that has passed through the purified water discharge port 5 flows into the backflow prevention device 100. The valve 101 rises due to the water pressure of the inflowing water, and as shown in FIG.
It stops at position 03. The inflowing water is the stopper 103.
At the position, the gas passes through the outer circumference of the valve 101, which is stationary, and flows into the hose 51 connected to the hose joint 14.

When the water tap 50 is closed, the valve 101, which has been stationary at the position of the stopper 103, is pushed down by the head pressure inside the hose 51 and descends, and then becomes stationary at the position of the valve seat 102.
Due to the head pressure, the valve 101 comes into close contact with the valve seat 102, so that water cannot flow back into the cartridge 4. For example, when replacing the cartridge 4 due to its life etc.,
Even if the backflow prevention device 100, which is connected to the hose joint 14 by removing the upper case 13, is removed from the purified water discharge port 5 of the cartridge 4, the residual water in the hose 51 is not backflowed by the backflow prevention device 100, so wet the surroundings. Instead, the cartridge 4 can be replaced. In FIG. 1, the angle θ is 90
Degree, dimension L ₁ is 3 mm, dimension L ₂ is 1.5 mm, radius of curvature R ₁
Is 3 mm, radius of curvature R ₂ is 1 mm, diameter φ ₁ is 6 mm, diameter φ ₂ is 1
The diameter of 4 mm and the diameter of φ ₃ are set to 9.8 mm.

Next, the operation of the backflow prevention device 100 of the present invention will be described in detail.

In most of the conventional backflow preventing devices, as shown in FIG. 4, the water inlet 205 is straight,
At this part, the water flow had a sudden change. According to this shape, the inlet loss coefficient Fi at the inlet 205 is
Is large (Fi = 1.5 according to the literature), the water flow becomes turbulent. As a result, the valve 201 rises in the valve operation chamber 204 due to water pressure, but the vortex 206 generated by the turbulence
There was a case where it was dragged in the downstream direction by the vibration, which caused vibration in the valve operation chamber 204, and the vibration generated an abnormal noise to the outside.

Therefore, according to the present invention, as shown in FIG. 3, the water inlet portion 105 of the backflow preventive device 100 is shaped so that the water inlet portion 105a has the largest opening area and approaches the valve operating chamber 104. The opening area gradually decreased, and the wall surface was made into a smooth curved surface shape (bellmouth shape).

Further, the opening diameter of the water inlet portion 105a is set to be substantially the same as that of the purified water discharge port 5.

According to this shape, the inlet loss coefficient Fi in the inlet portion 105 is about 1/40 of that of the conventional straight shape of FIG. 4 (according to the literature, Fi = 0.01 to 0.0).
In 6), the water flow is laminar. As a result, the valve 101 rises in the valve operating chamber 104 due to the water pressure, and the stopper 10
It will be stationary at position 3. The water that has flowed in passes through the outer periphery of the valve 101 that is stationary at the position of the stopper 103.

That is, the backflow prevention device 100 of the present invention is
Since the flow of water that has passed through the inlet portion 105 and flowed into the valve operation chamber 104 is a laminar flow, the valve 101 is stationary at the position of the stopper 103 due to the water pressure, so that abnormal noise to the outside due to vibration of the valve 101 occurs. Occurrence can be prevented.

[0026]

In the backflow prevention device of the present invention, the flow of water that has passed through the inlet portion and flowed into the valve operation chamber is laminar.
Since the valve stops at the position of the stopper due to the water pressure, it is possible to prevent the generation of abnormal noise to the outside due to the vibration of the valve.

[Brief description of drawings]

FIG. 1 is an overall cross-sectional view of a backflow prevention device according to an embodiment of the present invention.

FIG. 2 is an overall sectional view of a water purifier incorporating a backflow prevention device.

FIG. 3 is an overall cross-sectional view of the backflow prevention device when the valve moves to the stopper position.

FIG. 4 is an overall cross-sectional view of a conventional backflow prevention device.

[Explanation of symbols]

5 ... Purified water discharge port, 100 ... Backflow prevention device, 101 ... Valve,
102 ... Valve seat, 103 ... Stopper, 104 ... Valve operating chamber,
105 ... Entrance.

Claims (2)

[Claims] 1. A backflow prevention device comprising a valve for preventing a backflow of discharged fluid, a valve seat for closely contacting the valve to prevent the outflow of the fluid, and a stopper for preventing the valve from popping out by the pressure of the fluid. The shape of the fluid passage from the fluid inlet of the backflow prevention device to the chamber where the valve operates is such that the opening area of the fluid inlet is the largest, the opening area gradually decreases, and the wall surface is smooth. A backflow prevention device having a curved surface shape. 2. The maximum opening diameter of a fluid inlet portion of the backflow prevention device according to claim 1, which is substantially the same as that of a discharge port of a device which is connected to the backflow prevention device and supplies fluid to the backflow prevention device. Backflow prevention device characterized by having a diameter.