JPH0247330Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a backflow prevention device for preventing backflow of tap water in water pipes, faucets, spout pipes, etc.

[Prior Art] A device for preventing water in a shower hose installed in a hot water mixing faucet from flowing back when the inside of the faucet becomes negative pressure is described in Japanese Utility Model Application No. 54-179525. There is. To briefly explain this conventional device (the name of the device in the publication is a device for preventing reverse siphon effect in faucets) according to FIGS. 7 to 9, a is a water supply pipe communicating with the faucet body. , b is a cap screwed onto the end of the water supply pipe, and c is a cylindrical valve box screwed onto the outer periphery of the cap b to form a valve chamber d. A valve seat plate e is fixedly mounted with its peripheral edge sandwiched therebetween. As shown in FIG. 9, the valve seat plate e has a fan-shaped inflow valve opening f that is transparently provided near the outer periphery, and the inflow valve opening f is always in communication with the water supply pipe a. An outlet g is provided at the center of the bottom of the valve box c, and the outlet g is connected to a shower hose (not shown).
communicate with. An intake valve hole h communicating with outside air is provided at the outer edge of the outlet g. j and j' are annular valve plates arranged so as to be freely movable within the valve chamber d. However, when water flows in the usual manner from the water supply pipe a, the water bypasses the inlet valve f and enters the valve chamber d from the outlet g, as shown by the arrow in Figure 7. leak. On the other hand, when the water supply pipe a becomes negative pressure and the valve plates j and j' are attracted to the inlet valve f, the intake valve hole h opens and the valve chamber d communicates with the atmosphere and the shower hose connected to the outlet g. The water inside can be drained outside.

However, this backflow prevention device cannot normally close the intake valve hole h unless it is installed so that the outlet g is at the bottom and the water supply pipe a is at the top, as shown in FIGS. 7 and 8. . That is, since the intake hole h is not blocked by the weight of the valve plates j and j', and the positions of the valve bodies j and j' in the valve chamber d are indefinite, the valve plates j and j' are There is a risk of water leaking from the intake hole h due to unstable movement. Also, during the freezing season in cold regions, it is necessary to drain all the remaining water inside, but if this backflow prevention device is installed upside down as shown in Figures 7 and 8, the valve chamber d Residual water inside may accumulate and freeze. Furthermore, even if the remaining water is removed, a film of water remains on the contact surface with the valve plate, which freezes solidly and prevents water from flowing again. For this reason, this backflow prevention device is limited to use in areas where there is no risk of freezing, and there are restrictions on the areas in which it can be used, which poses problems such as the inability to freely distribute it as a product.

[Purpose of the invention] Therefore, the purpose of the invention is to create a backflow prevention device that can completely discharge residual water, break the contact between the inflow valve port and the valve body, eliminate freezing and sticking due to a water film, and can be used in frozen areas. Our goal is to provide the following.

[Means for Achieving the Object] In order to achieve the above object, the backflow prevention device of the present invention has an inflow valve port and an outflow port provided oppositely on opposing walls of the valve chamber, and an outer edge of the outflow port that communicates with the outside air. an intake valve hole is opened, and a valve body capable of selectively closing the inflow valve port or the intake valve hole is provided in the valve chamber so as to be movable back and forth;
Furthermore, the present invention is characterized in that a spring body is provided which biases the valve body to an extent that exceeds its own weight and closes the intake valve hole.

[Operation] Due to the elasticity of the spring body, the valve body closes the intake valve hole, and when water is passed through, it receives further water pressure and strongly closes the intake valve hole. Therefore, even when the water pressure is low at the beginning of water flow, the intake valve hole is reliably closed and there is no risk of water leakage due to accidental movement of the valve body. Furthermore, when a negative pressure is generated on the primary side, the valve body is sucked against the elasticity of the spring body to reliably close the inflow valve port, and at the same time, the intake valve hole is opened and the remaining water on the secondary side is discharged.

[Embodiment] Next, an embodiment of the present invention will be described with reference to FIGS. 1 to 6. 1 is a water supply pipe connected to a water source, 2 is a cap screwed onto the end of the water supply pipe, 3 is a cylindrical valve box screwed onto the outer periphery of the cap 2 to form a valve chamber 4, and 5 is the screw. Shows the water seal gasket at the joint. Therefore, an inflow valve port 6 penetrating into the valve chamber 4 is formed in the cap 2, and a plurality of ribs 7 are formed radially on the inner peripheral surface of the cap 2, and the bearing portion 8 is connected to the inflow valve port by the ribs. It is formed in the center so as to be integrated with the base. On the other hand, an outflow port 9 is formed in the valve box 3 so as to face the inflow valve port 6, and a plurality of ribs 10 are formed radially on the inner peripheral surface of the outflow port 9, and a bearing portion 11 is placed in the center of the outflow port 9. It is formed integrally with the valve box. 12 is the outlet 9
This is an intake valve hole that communicates with the outside air, which is opened at the outer edge of the valve. The guide shaft 13 has both ends connected to the bearing parts 8 and 11.
It is pierced by the valve chamber 4 and is supported in the valve chamber 4 in a vertical manner.
Reference numeral 14 denotes a valve body that is slidably passed through the guide shaft 13, and this valve body faces the inflow valve port 6 and has an annular plate-shaped rubber check valve body 15 that can open and close it. Several bosses 16 integrally protruding from the back surface are fitted into mounting holes formed in the plastic valve body and are fixed thereto, and a boss 16 faces the intake valve hole 12 and can be opened and closed. It is made up of an annular plate-shaped rubber intake valve body 17, and several bosses 18 integrally protruding from the back surface of the valve body 17 are fitted and fixed into mounting holes formed on the opposite side of the same valve body. Also, 19
A coil-shaped spring body is interposed between the bearing portion 8 and the valve body 14, and the elasticity of the spring body biases the valve body 14 to an extent that exceeds its own weight. In this way, the valve body 1
4 is slidable along the guide shaft 13, so when the intake valve body 17 closes the intake valve hole 12, the other check valve body 15 closes the inflow valve port 6 as shown in FIG. and the intake valve body 17 on the opposite side.
When the check valve body 15 is separated from the intake valve hole 12, the check valve body 15 closes the inflow valve port 6, as shown in FIG.

In the backflow prevention device configured in this manner, the elasticity of the spring body 19 bears the weight of the valve body 14 and lifts the valve body 14, as shown in FIG. This, combined with the internal water pressure, ensures that the intake valve hole is blocked and prevents water leakage. On the other hand, when the primary side becomes negative pressure, the valve body 14 is sucked, and the check valve body 15 closes the inflow valve port 6 as shown in FIG. Discharge to the outside as indicated by the arrow.

If there is a risk of freezing, draining water from a faucet or a drain valve (not shown) in the pipe will first act to prevent backflow as shown in Figure 2, closing the inlet valve port 6 and closing the intake valve hole 12. be opened. Therefore, the remaining water on the secondary side is discharged to the intake valve hole 12 or the secondary side opening. On the other hand, the negative pressure on the primary side sucking the valve body 12 weakens as water drains from the drain valve, and finally reaches atmospheric pressure. Then, the elasticity of the spring body 19 lifts the valve body 14 and opens the inflow valve port 6. Therefore, the remaining water in the valve chamber 4 is discharged to the primary side through the inflow valve port 6, as shown in FIG. 3, and the remaining water is completely eliminated. Further, since the valve body 14 is biased by the spring body 19, the inflow valve port 6 is maintained in an open state and the intake valve hole 12 is maintained in a closed state. Therefore, no problem occurs when water is recirculated after freezing.

[Effects of the invention] As explained above with respect to the embodiments, the backflow prevention device of the present invention has an intake valve hole that is normally closed and an inflow valve opening that is normally open due to the biasing force of the spring body. , it can be used regardless of whether it is inside or outside the cold freezing area. In addition, when the negative pressure suction force on the primary side disappears, the valve body separates from the inlet valve port, so there is no possibility that the water film will freeze and make water flow impossible, and water will not leak from the intake valve hole. There are various effects such as no fear.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a backflow prevention device showing an embodiment of the present invention, Figs. 2 and 3 are operational state diagrams of Fig. 1, and Fig. 4 is a cross-section taken along line A-A of Fig. 1. Figure 5 is a sectional view taken along line B-B in Figure 1, Figure 6
The figure is a cross-sectional view taken along the line C--C in Figure 1, Figure 7 is a vertical cross-sectional view of a conventional backflow prevention device, Figure 8 is a diagram of its operating state, and Figure 9 is a view of the valve seat plate in Figure 7. FIG. 4...Valve chamber, 6...Inflow valve port, 9...Outflow port,
12... Intake valve hole, 14... Valve body, 15... Check valve body, 17... Intake valve body, 19... Spring body.

Claims (1)

[Scope of utility model registration request] An inflow valve port and an outflow port are provided oppositely on opposing walls of the valve chamber, an intake valve hole communicating with outside air is provided at the outer edge of the outflow port, and the inflow valve port or the intake valve hole is selectively closed. A valve body is provided in the valve chamber so as to be movable back and forth, and a spring body is provided which biases the valve body to an extent exceeding its own weight to close the intake valve hole. Device.