JP3476666B2 - Backflow prevention device - Google Patents

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 used to prevent backflow of low quality water from a customer to a water supply side in a water pipe or the like.

[0002]

2. Description of the Related Art FIG. 3 is a diagram showing the structure of a conventional check valve. As shown in the figure, the conventional check valve is composed of a movable valve body 4 which is pressed against a valve seat 2 in a frame 1 by a preload spring 3, and the pressure on the inlet 5 side is on the outlet 6 side. When the pressure at the outlet 6 is higher than the pressure at the inlet 5, the movable valve body 4 is pressed against the valve seat 2 when the pressure at the outlet 6 is higher than the pressure at the inlet 5. Cut off the flow.

In the above-mentioned conventional check valve, a slight pressure difference is required between the inlet 5 and the outlet 6 because of the fluid flow, and the energy loss corresponding to the product of the pressure difference and the flow rate is lost. Occurs. In order to reduce the energy loss, there is also one in which the pressurizing spring 3 is omitted and the valve is closed by its own weight (for example, [Water Supply Facility Design Guide / Comment] 199 published by Japan Water Works Association).
See page 655, etc.

A check valve that is closed by the weight of the valve is described in the above-mentioned document [2. As described in the section [Lift type], some leakage is unavoidable when the valve should be closed, and the reliability of the backflow prevention becomes low. Therefore, in the prior art, the pressurizing spring 3 is used as shown in FIG. 3, and further, the same page [1. As shown in [Spring type 2) Double check valve], two units were used in series in preparation for increased loss.

[0005]

As described above, in the conventional check valve using the pressurizing spring, energy loss corresponding to the product of the pressure difference and the flow rate is generated, and the pressurizing spring is used. In a check valve that is closed by the dead weight of the slip valve, there is a problem that the reliability of the backflow prevention becomes low. Therefore,
The inventors of the present invention, when the function of the check valve is not necessary,
A check valve having an electromagnetic operation function capable of opening a large cross-sectional area of the flow passage portion determined by the gap between the valve seat 2 and the movable valve body 4 has been proposed (JP-A-7-243542).

FIG. 4 is a diagram showing the configuration of the check valve having the electromagnetic operation function. As shown in the figure, an electromagnetic actuator 7 composed of an electromagnetic coil 8 and an armature 9 is added to a check valve composed of a preload spring 3, a valve seat 2 and a movable valve body 4. In the check valve shown in the same figure, when the function of the check valve is not required at the time of flow and water stop, the movable iron core 9 is attracted by energizing the winding 8 of the electromagnetic actuator 7. The movable valve body 4 is forcibly pushed up against the force of the preload spring 3, and the cross-sectional area of the flow passage portion determined by the gap between the valve seat 2 and the movable valve body 4 is made large open, reducing the loss during fluid flow. It can be done. Further, by keeping the valve open even when the water is stopped, it is possible to reduce the frequency of operation of the check valve and prevent dust from clogging the valve seat.

The check valve having the electromagnetic operation function can avoid the energy loss due to the fluid flow when the function as the check valve is not required, but the check valve is installed in the feed water pump circuit. It is good that conditions such as pump operation that do not cause backflow can be obtained, but there are problems in applications where it is difficult to obtain information on the flow direction, such as water distribution network. The present invention has been made in view of the above circumstances, and an object of the present invention is to automatically open a valve to avoid energy loss when the check function is not necessary in the flow of fluid, and also to improve the reliability of the backflow function. It is an object of the present invention to provide a backflow prevention device that can improve the performance.

[0008]

As shown in FIG. 3, the loss due to the fluid flow of the conventional check valve pushes up the movable valve body 4 against the force of the preload spring 3 to flow the fluid. It occurs to let. Therefore, when the function of the check valve is not necessary, the movable valve body 4 is automatically pushed up against the force of the preload spring 3, and the cross-sectional area of the flow passage portion determined by the gap between the valve seat 2 and the movable valve body 4 is determined. It is good to open a large.

Therefore, the present invention is based on the above-mentioned JP-A-7-
The above problem is solved by combining a check valve having an electromagnetic operation function as shown in Japanese Patent No. 243542 and means for discriminating the flow direction of fluid. That is, the present invention is an electromagnetic actuator that holds a valve body of a check valve in an open position, which opens when the pressure on the inlet side is higher than the pressure on the outlet side and closes when the pressure on the outlet side is higher than the pressure on the inlet side. , The flow direction determining means for determining the flow direction of the fluid, and the output of the flow direction determining means, and the electromagnetic actuator is operated when the flow direction of the fluid is in a predetermined direction and when water is stopped. A fluid backflow prevention device is constituted by the drive means for holding the valve element in the open position.

With the above structure, when the fluid flow direction is not the predetermined direction and the water is not stopped, it can function as a normal check valve, and when the fluid flow direction is the predetermined direction. , It is possible to automatically open a large cross-sectional area of the flow passage portion. Therefore, it is possible to avoid energy loss due to fluid flow without impairing the function as the check valve.

In addition, the above-mentioned flow direction determining means includes a movable piece whose position is displaced by the flow of the fluid installed in the conduit and a height for detecting the approach of the metal attached to the tip of the movable piece.
It consists of a frequency oscillator circuit,
The metal at the tip of the movable piece approaches the coil.
The flow direction is determined by the
Displacement of the above movable piece is detected by the change of vibration state and the flow direction
By configuring so as to determine, the above-mentioned flow direction determining means can be configured by a simple and inexpensive device.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram of a first embodiment of the present invention. In the figure, reference numeral 13 is a check valve having the electromagnetic operation function illustrated in FIG. 4, and those denoted by the same reference numerals as those in FIG. 4 are parts having the same function, and therefore description thereof will be omitted. Figure 4
In the above, a method of pushing up the valve body 4 to the open position by the rod 10 by the operation of the armature 9 of the electromagnetic actuator 7 is illustrated, but in FIG. 1, the valve body 4 is moved by the rod 10 by the operation of the armature 9. Shows a method of attracting to the opening position.

Further, in FIG. 4, an actuator is installed inside the check valve.
1 is installed, but in FIG. 1, it is an example installed outside the check valve. The frame penetration portion of the rod 10 prevents leakage of the liquid by the seal 14. Reference numeral 15 is a device that determines the flow direction of the fluid. The flow meter 19 detects the flow rate of the fluid, and when the flow direction of the fluid is the normal direction and water is stopped, an electrical output is generated on the output line 16. The electromagnetic actuator drive circuit 17 is operated to supply the electric power from the power supply 18 to the winding 8 of the electromagnetic actuator 7 so that the valve seat 4 of the check valve is fixed at the open position.

Various devices can be applied as the device 15 for determining the flow direction of the fluid, for example, the flow meter 1
An electromagnetic flowmeter generally used as 9 is used, and when the flowmeter output 20 exceeds a predetermined lower limit value 21 in the normal flow direction, the comparator 22 may generate the output.

However, such a flow meter is expensive, and in the present invention, it is not always necessary to accurately measure a wide range of flow rates, and the purpose can be achieved if the flow direction can be determined within a relatively small flow rate range. Therefore, a simpler device can be used.

FIG. 2 is an explanatory view of an embodiment in which a simpler device is used as a device for discriminating the flow direction of fluid. The components with the same numbers as those in FIG. 1 are components having the same function, and therefore their explanations are omitted. In FIG. 2, a movable piece 26, which is supported by the shaft 25 of the support portion 24 and is displaced in the flow direction by the flow of the fluid, is installed inside the conduit 23. 27
Is a detection head that detects the displacement of the movable piece 26 caused by the fluid flowing in the normal direction, and generates an electrical output on the output signal line 29 of the detection converter 28.

As the displacement detector of the movable piece 26, for example, one that magnetically detects the approach of the metal 30 attached to the tip of the movable piece, a coil forming a high-frequency oscillation circuit is provided in the detection head, and the movable piece is placed. Various things such as one that utilizes the change of the oscillation state due to the approach of the metal 30 attached to the tip or one that optically detects the approach of the movable piece 26 can be used, but here, as an example. , A coil 31 forming a high frequency oscillation circuit in the detection head 27
Next, a method of utilizing the fact that the oscillation state changes due to the approach of the metal 30 attached to the tip of the movable piece will be described.

That is, when the movable piece 26 is displaced in the direction of the position [A] in the figure by the fluid flowing in the normal direction, the flow rate is extremely reduced so as to come to the position facing the detection head 27. The flow direction is reversed and the movable piece 26 is shown in the figure [B].
When it comes to the position, the metal piece 30 is attached to the movable piece so that the metal piece 30 attached to the movable piece 26 does not face the detection head 27. If a non-metal such as a synthetic resin is used for the conduit 23, the detection head 27 is provided outside the conduit 23 as shown in FIG.
It is also possible to put.

With this structure, the flow direction of the fluid can be easily configured. Further, since the movable piece 26 only needs to discriminate only the fluid flow direction, it is possible to use a part of the cross-sectional area of the conduit, and it is easy to select a shape that reduces the loss of fluid flow. .

Although FIG. 2 shows an example in which the device 15 for determining the fluid flow direction is installed close to the outlet side of the check valve 13 with electromagnetic operation, the device 15 for determining the fluid flow direction is shown.
The installation position of is not necessarily limited to this position. That is, in the above-mentioned configuration, in practice, there is often a closed pipe line having no flow path other than the check valve having an electromagnetic operation function to the demand end and having a considerable extension distance. In such a case, the installation position of the fluid flow direction determination device 15 does not necessarily have to be installed near the outlet of the check valve having the electromagnetic operation function, but installed near the demand end of the closed pipe. However, the same effect can be obtained. Generally, an electric measurement control device requires regular inspection / inspection, but if the installation position of the fluid flow direction determination device 15 is separated and installed at a position easy to inspect / inspect, maintenance is required. Very convenient for inspection.

The fluid flow direction discriminating device 15 constructed as shown in FIG. 2 has a simple construction and can be constructed at low cost. Further, when the high-frequency oscillation method as shown in FIG. 2 is used in the flow direction determining apparatus, there may be a failure of the semiconductor used, but in the case of short-circuiting, disconnection, or performance deterioration of the semiconductor element forming the high-frequency oscillation circuit. Since the high frequency oscillation is stopped, it is possible to eliminate the device output 29 and prevent the electromagnetic actuator from operating. At this time, check valve 1
No. 3 operates as a normal check valve with a strong pressurizing spring, so the loss at the time of flow is increased, the reliability of backflow prevention is secured, and a so-called fail-safe function can be provided. . Moreover, the state at the time of a power failure is the same, and similarly high reliability can be secured.

In the above embodiment, the actuator 7 is installed outside the check valve, and the check valve of the type in which the valve body 4 is pulled to the open position by the operation of the armature 9 is used. As the check valve with an operation function, the one shown in FIG. 4 can be used, and the check valve shown in FIG. 4 can also be used to obtain the same effect as the above embodiment.

[0023]

As described above in detail, according to the present invention, when the flow direction is a predetermined direction, the electromagnetic actuator attached to the check valve is automatically biased to forcibly reverse the direction. Since the stop valve is opened, the energy loss for fluid flow can be reduced without impairing the function of the check valve, and in particular, the energy loss at a large flow rate can be significantly reduced. Also, when the flow direction is not the specified direction, and when the flow rate decreases and backflow occurs, the electromagnetic actuator is not energized and it is equivalent to a normal check valve with a strong preload spring. Therefore, it is possible to perform highly reliable check with less leakage.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a device for determining a fluid flow direction according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a conventional check valve.

FIG. 4 is an explanatory diagram showing an example of a check valve having an electromagnetic operation function.

[Explanation of symbols]

1 Check valve frame 2 Check valve seat 3 Preload spring 4 Movable valve body 5 Check valve inlet 6 Check valve outlet 7 Electromagnetic actuator 8 Electromagnetic coil of electromagnetic actuator 9 Armature of electromagnetic actuators 10 Rod that connects the valve body and the electromagnetic actuator 11 electromagnetic coil 8 terminals 12 Other terminals of electromagnetic coil 8 13 Check valve with electromagnetic operation 14 seal 15 Flow direction determination device 16 Current flow output line 17 Electromagnetic actuator drive circuit 18 Electromagnetic actuator drive power supply 19 Flowmeter 20 Flow rate output 21 Regular flow minimum flow rate setting 22 Comparator 23 pipelines 24 Support 25 axes 26 movable pieces 27 Detection head 28 Detection converter 29 Detection converter output line 30 metal pieces 31 coils

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Sakae Onuki, Sakae, Nagano Prefecture, Matsumoto City, Nagano Prefecture, 3046, Sasaga, Nihon Valve Co., Ltd. (72) Inventor, Norihiko Kasugai, 518-3 Futako, Takatsu-ku, Kawasaki, Kanagawa (56) Reference Reference Japanese Unexamined Patent Publication No. 7-243542 (JP, A) Actual development 61-124771 (JP, U) Actual development 1-118262 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16K 15/00-15/20 F16K 31/06

Claims (2)

(57) [Claims] 1. An electromagnetic actuator for holding a valve body of a check valve, which is opened when the pressure on the inlet side is higher than the pressure on the outlet side and closed when the pressure on the outlet side is higher than the pressure on the inlet side, in an open position. And the flow direction determining means for determining the flow direction of the fluid, and the electromagnetic actuator operated by the output of the flow direction determining means when the flow direction of the fluid is a predetermined direction or in a water stop state. the by operating a drive means for holding the valve body in the opening position, the through-flow direction determination means, passing of the installed fluid conduit
The movable piece whose position is displaced by the flow and the tip of the movable piece
Detecting the approach of a metal attached to with a high-frequency oscillator, the high frequency oscillation circuit, on the coil of the high-frequency oscillator
Note that the oscillating state is
The flow direction is determined by the means for determining the flow direction.
Displacement of the above movable piece is detected by the change of vibration state and the flow direction
A fluid backflow prevention device characterized by determining 2. The fluid backflow prevention device according to claim 1 , wherein the flow direction determining means is provided near the demand end of the outlet side closed pipe of the check valve having an electromagnetic operation function.