JP3456249B2 - Valve structure of backflow prevention water drain valve - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve structure of a water drainage plug which is used in a cold region and has a check ring mounted on a piston. 2. Description of the Related Art Conventionally, a check valve is often provided in the middle of a water supply pipe in order to prevent a back flow due to a negative pressure generated on a main pipe side. For the sake of simplicity, for example, Japanese Utility Model Publication No.
As disclosed in Japanese Patent Publication No. 34-34, a device in which a check valve is attached to a piston of a water drainage plug has been proposed and put to practical use. Separately, recently, direct water supply has been performed on the 3rd and 5th floors, etc., and a drain plug with a small head loss has been demanded accordingly. In this case, since the downstream pipe becomes higher in the vertical direction, at the time of drainage, the water pressure causes the check valve body to press the spring, thereby closing the cylinder between the inflow port and the drain port, thereby preventing the drainage from being performed. Occurs. To solve this problem, it is only necessary to increase the strength of the spring, but this time, the loss head becomes large, and the problem that it cannot be used practically comes out. SUMMARY OF THE INVENTION In view of the above, the present invention provides a proper drainage irrespective of the height of the downstream pipe, and does not increase the spring force or use a spring. It is an object to provide a water tap with a low head loss. [0004] Therefore, the present invention provides an inlet above the side wall of the valve box, an outlet at the middle of the side wall, and a drain at the lower end. A large-diameter cylinder is provided between the outlet and a small-diameter cylinder is provided between the outlet and the drain, and a small-diameter cylinder is provided between the upper piston sliding on the large-diameter cylinder and the lower piston sliding on the small-diameter cylinder. A check valve that is pressed upward by a spring or buoyancy to close the cylinder between the inflow port and outflow port, and has a contact part for the check valve body at the top of the small-diameter cylinder when draining. In addition, a drainage channel is formed at the lower end of the check valve body. According to the present invention, a drain port is provided at the lower end of the valve box, and the cylinder between the outlet and the drain port is formed to have a smaller diameter than the cylinder between the inlet and the outlet where the check valve body is in close contact. In addition, since a drainage channel is formed at the lower end of the check valve body, the check valve body does not block the drain port regardless of the height of the downstream piping, and therefore, the spring may be weak or buoyancy. The use of a spring eliminates the need for a spring, so that it can withstand use even as a directly connected tap water supply plug on the third and fifth floors. An embodiment will be described with reference to the drawings. FIG. 1 shows an embodiment in which the present invention is applied to a water drainage plug used without being buried in the soil. A valve box 1 has an inflow port 2 above the side wall, an outflow port 3 in the middle of the side wall, and a lower end axial center portion. A drain port 4 is formed in the first cylinder 5 inside the inflow port 2 on the axis.
A second cylinder 6 is provided between the inflow port 2 and the outflow port 3, and a third cylinder 7 is formed between the outflow port 3 and the drain port 4 with a smaller diameter than the first cylinder 5 and the second cylinder 6. .
Reference numeral 8 denotes a piston body, an upper piston 11 on which an annular packing 9 sliding on the first cylinder 5 and an annular packing 10 sliding on the second cylinder 6 and an annular packing sliding on the third cylinder 7 at the lower end. 12, a lower piston 14 having a small-diameter portion 13 above, and an upper end of the small-diameter portion 13 being screw-connected to the upper piston 11;
A non-return gasket 15 closely attached to the second cylinder 6 is attached to the small-diameter portion 13 and an inner non-return gasket 16 sliding on the small-diameter portion 13 is attached to the inner circumference. Check valve element 18 constantly pressed upward by spring 17
Is fitted. The check valve element 18 has a drain passage 19 formed of a cross-shaped square groove at the lower end, and a drain passage is provided between the check valve element 18 and the contact part 20 at the upper end of the third cylinder 7 with which the check valve element 18 contacts. Has formed. The inner non-return packing 16 is connected from the outlet 3 to the inlet 2
A one-way sealing packing having a Y-shaped cross section that blocks only the flow of water in one direction is used. Therefore, the frictional resistance is smaller than when, for example, an O-ring is used, and the operation is performed smoothly. An upper lid 22 having an internal thread 21 for operation is connected to an upper end of the valve box 1, and a handle 2 is attached to the upper end.
3 and a spindle 25 having an external male screw 24 for screwing with the internal female screw 21 is rotatably connected to the upper piston 11. FIG. 1 shows a state of flowing water, in which water flowing from an inlet 2 passes through a gap between a cylinder 6 and a small-diameter portion 13.
The spring 17 is pressed to lower the check valve body 18 and the inlet 3
Although not shown, the water flows through the downstream vertical pipe, that is, the rising pipe, to the faucet at the end. At this time, there is no water leakage to other places by the action of the annular packings 9 and 12. In this state, when a negative pressure is generated on the main pipe side due to water cutoff or the like, the check valve element 18 instantaneously rises due to the restoring force of the spring 17, the check packing 15 comes into close contact with the second cylinder 6, and Since the inner non-return packing 16 is in close contact with the small-diameter portion 13, water on the outlet 3 side flows to the inlet 2 side, so-called backflow does not occur. Next, when it is desired to drain the water in the riser pipe in winter, when the handle 23 is turned, the spindle 25 descends while rotating by the actuating male screw 24 screwed into the actuating female screw 21, and accordingly the piston body is rotated. 8 also descends, first the annular packing 10 comes into close contact with the second cylinder 6 to shut off the water from the inflow port 2, and further descends, this time the annular packing 12 separates from the third cylinder 7 and stands up. The water in the upper pipe is discharged to the drain 4 side. At this time, when the rising pipe head is high, the check valve body 18 descends due to the water flow and attempts to close the third cylinder 7, but in the present invention, the third cylinder 7 is made smaller in diameter than the check valve body 18. Due to the formation, the lower end of the check valve element 18 comes into contact with the contact portion 20 at the upper end of the third cylinder 7 and stops, and is discharged to the drain port 4 side through the drain passage 19 formed of a cross-shaped square groove. You. When the drainage proceeds and the rise pipe has a small amount of water, the check valve element 18 rises and stops until it contacts the lower end of the upper piston 11 due to the restoring force of the spring 17. FIG. 2 shows an embodiment in which the present invention is applied to a water drainage plug buried and used in the soil. A drain port 4 is not provided on the axis but on the side wall. 1 Install a check valve so that it does not get inside. A pipe 26 is connected to the upper end of the valve box 1 and is extended to the above-ground portion to be fixed to the operation unit main body (not shown). The piston body 8 is also a rod 27
And is connected to a handle at the upper end through an operation rod that moves up and down in the operation unit body. Upper piston 1
1 is provided with a small-diameter portion 13 and is screwed at its lower end to a lower piston 14. The check valve element 18 is provided with a check packing 15 made of a one-way sealing packing having a Y-shaped cross section on the outer periphery, and a taper surface 28 at an upper end portion of the inner surface to form an upper piston 11.
The seating surface of the inner non-return packing 16 mounted on the small diameter portion 13 is formed. Drilling canal 19 with several round holes at the lower end
And Furthermore, it is made of a resin having a specific gravity smaller than 1, and is raised by buoyancy without using a spring. The figure shows a drained state, in which water from the inflow port 2 is blocked by annular packings 9 and 10 which are in close contact with the first cylinder 5 and the second cylinder 6, and water in the riser pipe is discharged from the outflow port. 3, the check valve 18 is pushed down until the lower end of the check valve 18 stops at the contact portion 20 at the upper end of the small-diameter third cylinder 7, and flows from the drain passage 19 to the drain port 4. . When a negative pressure is generated on the main pipe side in a water-flowing state, the check valve body 18 rises due to buoyancy, the check packing 15 comes into close contact with the second cylinder 6, and the tapered surface 28 contacts the inner check packing 16. Touch to prevent backflow. As described above, in the present invention, the cylinder between the drain port provided at the lowermost end and the outlet above the drain port is formed smaller in diameter than the other cylinders. After the lower end of the check valve abuts on the small-diameter cylinder and stops, and a drainage channel is provided at the lower end of the check valve body, a weak spring is sufficient no matter how high the riser pipe becomes, Since it can be omitted, it is possible to provide a valve structure of a backflow prevention type water drain valve which is most suitable for a water drain plug having a small head loss used on the third floor, the fifth floor, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing a water flowing state according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing another embodiment of the present invention in the same water flowing state. [Description of Signs] 1 Valve box 2 Inlet 3 Outlet 4 Drainage port 5 First cylinder 6 Second cylinder 7 Third cylinder 8 Piston bodies 9, 10, 12 Annular packing 11 Upper piston 13 Small diameter section 14 Lower piston 15 Check packing 17 Spring 18 Check valve 19 Drainage channel 20 Contact part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16K 11/044 E03B 7/10 F16K 15/00

Claims (1)

(57) [Claims 1] An inlet is provided above the side wall, an outlet is provided at an intermediate portion of the side wall, a drain port is provided at a lower end, and a first cylinder is provided above the inlet. An upper piston having an annular packing attached to the first cylinder and the second cylinder in a valve box having a second cylinder between the inlet and the outlet and a third cylinder between the outlet and the drain; It consists of a lower piston on which an annular packing that is in close contact with the cylinder is mounted, and a small-diameter portion provided between the two pistons. In a water drainage plug in which a piston body fitted with a check valve body receiving an upward pressing force slides to select a water-flow state or a drainage state, the third cylinder is formed to have a smaller diameter than the first and second cylinders. , Check on top of 3rd cylinder Abutment provided with a valve structure of a backflow prevention type drain tap obtained by forming a drainage channel in the lower end portion of the check valve's body.