Drain valve

Abstract

The entire drain valve is simplified both structurally and aesthetically, reducing the number of parts and thus lowering component and manufacturing costs, while also making the overall design smaller and lighter. Exposed parts are eliminated to protect the drain valve from external disturbances such as wind, rain, and snow. [Solution] The device comprises a riser pipe section 2 consisting of a single cylindrical section 11 and a single transmission rod section 12 arranged coaxially with the cylindrical section 11, and an inverted cup-shaped operating handle section 3 having an upper end surface section 3u and a cylindrical circumferential surface section 3f. The circumferential surface section 3f is extended downward so as to overlap with the upper end section 11u of the cylindrical section 11, the upper end section 12u of the transmission rod section 12 is attached to the upper end surface section 3u, and the lower end section 12d of the transmission rod section 12 is attached to a valve body section 14 that opens and closes the main water channel R.

Description

Technical Field

[0001] The present invention relates to a drain plug installed outdoors such as in the garden of a house in a cold region.

Background Art

[0002] Generally, in outdoors such as in the garden of a house in a cold region, a drain plug for preventing freezing equipped with a riser pipe having an operation handle at the upper end is often installed.

[0003] Conventionally, a drain plug for preventing freezing has a function of draining water by closing the main water passage and opening the drain passage by turning an operation handle arranged at the upper end. As this type of drain plug, the drain plug device described in Patent Document 1 and the drain plug described in Patent Document 2 are known.

[0004] The drain plug device of Patent Document 1 aims to provide a drain plug device capable of simultaneously performing water passing and draining of a plurality of water passages in a water supply system having a plurality of water passages for supplying both hot water and cold water from respective faucets. Specifically, it includes a plug unit portion connected in the middle of a water supply pipe, a transmission shaft portion arranged above it, and an operation handle portion for operating the plug unit portion via this transmission shaft portion. By operating the operation handle portion, the valve body of the plug unit portion is displaced to enable switching of the water supply pipe to a water passing or draining state. The plug unit portion also has a plurality of drain mechanisms for draining the tap water of the plurality of water passages respectively, and a valve that functions simultaneously when opening and closing these, enabling simultaneous water passing and draining states of the respective tap waters in the plurality of water passages.

[0005] Furthermore, the drain valve described in Patent Document 2 aims to provide a drain valve that does not require a sand-stopping cover for drainage, has high drainage performance, allows for easy replacement of water-stopping packings and draining packings, and has no intermediate water leakage. Specifically, by making the fitting portion between the valve body and the outer cylinder intermittent, a space (gap) is formed, eliminating the multiple drain ports that were provided on the outer cylinder and giving them the function of a sand-stopping cover. The water-stopping compartment, which is detachably fitted to the lower spindle of the operating part and has a drainage channel inside, has a water-stopping packing that covers its tip and a draining packing that is spaced apart and facing it. The water-stopping and draining packings are integrated with the water-stopping compartment by bonding, baking, etc. The water-stopping packing consists of a protruding central part that covers the tip and a peripheral part that is connected at a right angle to the protruding part. A groove with a U-shaped cross-section is formed in the part of the peripheral part that is in contact with the protruding part, and a partially rounded (R) part is formed on the outer surface of the protruding part. The draining packing is also configured to have a groove with a U-shaped cross-section in the peripheral part that is in contact with the protruding part. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 10-114974 [Patent Document 2] Japanese Patent Publication No. 2007-327249 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, the drain valves described in Patent Documents 1 and 2 mentioned above also had the following problems that needed to be solved.

[0008] In other words, the basic structure of this type of drain valve consists of a riser pipe section installed on the ground or elsewhere, and an operating handle section for user operation, with the riser pipe section and the operating handle section being configured as distinct, separate functional parts. Specifically, the riser pipe section comprises an outer cylinder section and an inner cylinder section, with the upper end of the riser pipe section covered by a cap, and the upper end of a transmission rod located inside the inner cylinder section protrudes upward through a cap provided at the upper end of the riser pipe section, with the operating handle section attached to the upper end of this transmission rod.

[0009] As a result, the entire drain valve became structurally and aesthetically complex, leading to increased component costs and manufacturing costs due to the increased number of parts. Furthermore, it resulted in an overall larger size and heavier weight, presenting several challenges that needed to be addressed. Moreover, the presence of a significant number of exposed parts, such as transmission rods, meant that the valve was not adequately protected from external disturbances such as wind, rain, and snow.

[0010] The present invention aims to provide a drain valve that solves the problems present in the background technology described above. [Means for solving the problem]

[0011] In order to solve the above-mentioned problems, the drain valve 1 according to the present invention is configured to drain water through a drainage channel Rs having a check valve 4 by operating the operating handle 3, which switches to a drainage mode. The drain valve is configured to drain water through a drainage channel Rs having a check valve 4, and is characterized by comprising a riser pipe 2 composed of a single cylindrical body 11 and a single transmission rod 12 arranged coaxially with the cylindrical body 11, and an inverted cup-shaped operating handle 3 having an upper end surface 3u and a cylindrical circumferential surface 3f, with the circumferential surface 3f extended downward so as to overlap with the upper end 11u of the cylindrical body 11, the upper end 12u of the transmission rod 12 attached to the upper end surface 3u, and the lower end 12d of the transmission rod 12 attached to a valve body 14 that opens and closes the main water channel R.

[0012] In this case, according to a preferred embodiment of the invention, it is desirable that the operating handle portion 3 has an uneven surface 15 formed on the outer circumferential surface 3f to prevent slippage during operation. Furthermore, the transmission rod portion 12 can be attached to the upper end surface portion 3u in a manner that restricts relative rotation and allows for detachable attachment. On the other hand, the transmission rod portion 12 can be supported by a rod support block 16 through which the transmission rod portion 12 passes and which is provided with a drainage channel Rs. In this case, the check valve 4 may be provided with a ball valve portion 17 housed in the drainage channel Rs, a restricting portion 18 provided on the upstream side of the drainage channel Rs to restrict the movement of the ball valve portion 17 upstream, a drainage branch channel Rsr provided between the ball valve portion 17 displaced to the downstream side Fd of the drainage channel Rs and the restricting portion 18, and a closing member 19 that closes the opening Rso on the downstream side of the drainage channel Rs. The blocking member 19 can be integrally formed in a C-shape from synthetic resin and configured to be fitted into a small-diameter portion 16s formed on the outer circumference 16f of the rod support block 16. On the other hand, the blocking member 19 has a cover portion 19c that closes the opening Rso of the drainage channel Rs, and a protrusion 19p that is inserted into the opening Rso can be provided on the lower surface of the cover portion 19c. [Effects of the Invention]

[0013] The drain valve 1 according to the present invention, having such a configuration, provides the following remarkable effects.

[0014] (1) The drain valve is configured with a riser pipe section 2 consisting of a single cylindrical section 11 and a single transmission rod section 12 arranged coaxially with the cylindrical section 11, and an inverted cup-shaped operating handle section 3 having an upper end surface section 3u and a cylindrical circumferential surface section 3f. By extending the circumferential surface section 3f downward, it overlaps with the upper end section 11u of the cylindrical section 11, and the upper end section 12u of the transmission rod section 12 is attached to the upper end surface section 3u, and the lower end section 12d of the transmission rod section 12 is attached to the valve body section 14 that opens and closes the main water channel R. As a result, the entire drain valve is simplified both structurally and in appearance, reducing the number of parts and thus reducing parts costs and manufacturing costs, as well as making the overall size and weight smaller. Moreover, there are no exposed parts, so the drain valve can be protected from disturbances such as wind, rain, and snow.

[0015] (2) In a preferred embodiment, if an uneven surface 15 is formed on the outer circumferential surface of the circumferential surface 3f to prevent slippage during operation, it can be easily and reliably turned in the same way as a normal operating handle, thereby improving operability and convenience.

[0016] (3) In a preferred embodiment, when the transmission rod portion 12 is configured such that relative rotation is restricted with respect to the upper end surface portion 3u and it is attached detachably, the connection and rotational transmission between the operating handle portion 3 and the transmission rod portion 12 can be reliably performed, and parts such as the valve body portion 14 can be replaced quickly and easily.

[0017] (4) In a preferred embodiment, if the transmission rod portion 12 is supported by a rod support block 16 through which the transmission rod portion 12 passes and which is provided with a drainage channel Rs, the drainage channel Rs can be provided using the rod support block 16, thereby enabling the construction of a drainage structure that can be easily and reliably switched to a drainage mode.

[0018] (5) In a preferred embodiment, when configuring the check valve 4, if a spherical valve section 17 is housed in the drainage channel Rs, a restricting section 18 is provided on the upstream side of the drainage channel Rs to restrict the movement of the spherical valve section 17 upstream, a drainage branch channel Rsr is provided between the spherical valve section 17 and the restricting section 18 which have been displaced to the downstream side Fd of the drainage channel Rs, and a closing member 19 closes the opening Rso on the downstream side of the drainage channel Rs, the check valve 4 can be configured using a part of the structure of the drainage channel Rs, thereby enabling miniaturization and simplification when installing the drainage channel Rs.

[0019] (6) In a preferred embodiment, when constructing the closing member 19, if the entire structure is integrally formed in a C-shape from synthetic resin and configured to fit into the small-diameter portion 16s formed on the outer circumference 16f of the rod support block 16, the closing member 19, being made of synthetic resin and having a C-shape, can be easily attached to the small-diameter portion 16s with a single touch.

[0020] (7) In a preferred embodiment, when forming the closing member 19, it has a cover portion 19c that closes the opening Rso of the drainage channel Rs, and a convex portion 19p to be inserted into the opening Rso is provided on the lower surface of this cover portion 19c. By locking the convex portion 19p to the opening Rso, positioning becomes possible, so that the attachment of the closing member 19 can be performed quickly and without variation.

Brief Description of the Drawings

[0021] [Figure 1] Front cross-sectional view showing the whole of the drain plug according to the preferred embodiment of the present invention (cross-section taken along line B - B in FIG. 2), [Figure 2] Plan view of the same drain plug, [Figure 3] End view taken along line A - A in FIG. 1 of the same drain plug, [Figure 4] Explanatory drawing of the attachment structure of the riser pipe portion and the operation handle portion in the same drain plug, [Figure 5] Explanatory drawing of the draining mode in the same drain plug, [Figure 6] Perspective view seen from the bottom surface direction of the closing member used in the same drain plug, [Figure 7] Front view of the same closing member, [Figure 8] Plan view of the same closing member, [Figure 9] Perspective view showing the state before attaching the same closing member to the rod support block, [Figure 10] Perspective view showing the state where the same closing member is attached to the rod support block,

Modes for Carrying Out the Invention

[0022] Next, preferred embodiments according to the present invention will be given and described in detail based on the drawings.

[0023] First, the overall configuration of the drain plug 1 according to the present embodiment will be described with reference to FIGS. 1 - 4.

[0024] The drain valve 1, as a basic configuration as shown in Figure 1, comprises a riser pipe section 2 consisting of a single cylindrical section 11 and a single transmission rod section 12 arranged coaxially with the cylindrical section 11, and an inverted cup-shaped operating handle section 3 having an upper end surface section 3u and a cylindrical circumferential surface section 3f. In this case, the operating handle section 3 is overlapped with the upper end 11u of the cylindrical section 11 by extending the circumferential surface section 3f downward. The transmission rod section 12 has its upper end 12u attached to the upper end surface section 3u of the operating handle section 3, and its lower end 12d attached to the valve body section 14 that opens and closes the main water channel R.

[0025] The riser pipe section 2 is constructed with a single cylindrical section 11 having a predetermined length and being in a straight line. While conventional riser pipe sections were constructed with a double-pipe structure having an outer cylindrical section and an inner cylindrical section, the riser pipe section 2 in this embodiment is constructed with a single cylindrical section 11.

[0026] As shown in Figure 4, the operating handle portion 3 is integrally formed in an inverted cup shape having an upper end surface portion 3u and a cylindrical circumferential surface portion 3f, and as shown in Figure 1, the circumferential surface portion 3f is extended downward so that it overlaps with the upper end portion 11u of the cylindrical portion 11. As a result, a predetermined range Lc, which is the overlapping portion of the inner circumferential surface at the lower part 3fd of the circumferential surface portion 3f, overlaps with a predetermined range of the outer circumferential surface at the upper end portion 11u of the cylindrical portion 11.

[0027] In this case, the lower part 3fd of the circumferential portion 3f, which is the overlapping portion, is formed to have a larger diameter than the original circumferential portion 3f, so that the lower end of the original circumferential portion 3f abuts against the upper edge of the upper end portion 11u of the cylindrical portion 11, and the lower part 3fd of the circumferential portion 3f, the cylindrical portion 11, and the upper end portion 11u become slidable.

[0028] Furthermore, a textured surface 15 is formed on the outer circumferential surface 3f of the operating handle portion 3 to prevent slippage during operation. This allows for easy and reliable rotation, similar to a normal operating handle, thereby improving operability and convenience. While the example given illustrates the formation of a textured surface 15 to prevent slippage of the operating handle portion 3, various other means can be used to prevent slippage, such as applying anti-slip processing or coating with anti-slip paint.

[0029] Then, as shown in Figure 4, a recess 3us is formed in the center of the upper end surface 3u of the operating handle portion 3, and a mounting hole 31 is formed in the bottom surface of this recess 3us. Below this mounting hole 31, a concave rod support portion 32 is formed into which the upper end 12u of the transmission rod portion 12 is inserted. In this case, the inner surface of the rod support portion 32 is formed as a tapered concave surface 32t, and the upper end 12u of the transmission rod portion 12 is formed as a tapered convex surface 12t that fits into the tapered concave surface 32t, taking into consideration the ease of attachment and detachment.

[0030] The transmission rod section 12 is composed of a single transmission rod section 12 arranged coaxially inside the cylindrical section 11. The transmission rod section 12 is located on the upper side and consists of a rod body section 12m attached to the operating handle section 3, and an auxiliary transmission section 12s connected to the lower end of the rod body section 12m. A valve body section 14 is attached to the lower end of the auxiliary transmission section 12s. The 14s is an auxiliary valve that opens and closes the drainage channel Rs and is supported by a spring provided between the valve body sections 14.

[0031] With the operating handle portion 3 and the transmission rod portion 12 configured in this way, after inserting the upper end 12u of the transmission rod portion 12 into the rod support portion 32 formed in the operating handle portion 3, the mounting screw 33 is inserted from above into the mounting hole 31 and screwed into the screw hole portion 34 provided in the upper end 12u of the transmission rod portion 12. This fixes the operating handle portion 3 to the upper end 12u of the transmission rod portion 12, and the operating handle portion 3 can be removed from the transmission rod portion 12 by loosening the mounting screw 33.

[0032] In this case, the tapered convex surface 12t of the upper end 12u of the transmission rod portion 12 and the tapered concave surface 32t of the rod support portion 32 are formed with a non-circular cross-sectional shape such as a hexagon to restrict relative rotation during installation. Furthermore, the recess 3us of the operating handle portion 3 is closed above the mounting screw 33 by, for example, detachably attaching an elastic cap member 35.

[0033] With this configuration, relative rotation with respect to the upper end surface 3u is restricted, and if it is detachably attached, the coupling and rotational transmission between the operating handle portion 3 and the transmission rod portion 12 can be reliably performed, and parts such as the valve body portion 14 can be replaced quickly and easily.

[0034] Furthermore, the upper part (upper end 12u) of the transmission rod section 12 is supported by the center of the operating handle section 3, and the lower part of the transmission rod section 12 is supported by the center of the rod support block 16, through which the transmission rod section 12 passes (as described later). As a result, the transmission rod section 12 has a support structure with high mechanical strength and rigidity due to the two-point support from above and below. This enables smooth and stable rotational operation.

[0035] On the other hand, the lower end of the cylindrical portion 11 is connected to the water pipe connection portion 41. As shown in Figure 1, the water pipe connection portion 41 includes an upstream connection port 42 connected to the upstream water pipe Pu, a downstream connection port 43 connected to the downstream water pipe Pd, a valve seat portion 45 that separates the upstream connection port 42 and the downstream connection port 43 and is formed by opening into the horizontal portion of the intermediate portion 44, and a cylindrical connection portion 46 that communicates with the downstream connection port 43 and rises upward in a cylindrical shape from the upper surface of the water pipe connection portion 41. As a result, the lower end of the cylindrical portion 11 is fixed to this cylindrical connection portion 46. In this case, the water channel between the upstream connection port 42 and the downstream connection port 43 becomes the main water channel R. In Figure 1, the dashed arrow W indicates the direction of water flow.

[0036] On the other hand, a rod support block 16 is provided on the outer circumferential surface of the lower part of the transmission rod portion 12, through which the transmission rod portion 12 passes and through which a drainage channel Rs is provided. As a result, the lower part of the cylindrical portion 11 and the transmission rod portion 12 are shielded by the rod support block 16, and the lower part of the transmission rod portion 12 is supported at the center of the rod support block 16.

[0037] Thus, when constructing the transmission rod section 12, if the transmission rod section 12 is supported by a rod support block 16 through which it passes and which is provided with a drainage channel Rs, the drainage channel Rs described later can be provided using this rod support block 16, thereby enabling the construction of a drainage structure that can be easily and reliably switched to a drainage mode.

[0038] Furthermore, the check valve 4 is equipped with a drainage channel Rs formed inside the rod support block 16, and as shown in Figure 5, it is composed of a spherical valve section 17 housed in the drainage channel Rs, a restricting section 18 provided on the upstream side of the drainage channel Rs to restrict the movement of the spherical valve section 17 upstream, a drainage branch channel Rsr provided between the spherical valve section 17 and the restricting section 18 which have been displaced to the downstream side Fd of the drainage channel Rs, and a closing member 19 that closes the opening Rso on the downstream side of the drainage channel Rs. In this case, the drainage channels Rs are provided in two locations that are 180° symmetrical with respect to the transmission rod section 12, but only one location is shown in Figures 1 and 5. With this configuration, the check valve 4 can be constructed using a part of the structure of the drainage channel Rs, thus enabling miniaturization and simplification when installing the drainage channel Rs.

[0039] In this case, the details of the closure member 19 are shown in Figures 6-8. The closure member 19 is integrally formed in a C-shape from synthetic resin and is configured to be fitted into the small-diameter portion 16s formed on the outer circumference 16f of the rod support block 16. Thus, because the closure member 19 is integrally formed in a C-shape from synthetic resin and is configured to be fitted into the small-diameter portion 16s formed on the outer circumference 16f of the rod support block 16, it can be easily attached to the small-diameter portion 16s with a single touch.

[0040] As shown in Figures 6-8, the closing member 19 has a cylindrical mounting portion 19m that is C-shaped in plan view, and a pair of cover portions 19c, 19c on both sides that are integrally provided at the lower end of the mounting portion 19m and close the opening Rso that is opened on the intermediate upper end surface of the rod support block 16 on the downstream side of the drainage channel Rs. The lower surface of these cover portions 19c... is provided with protrusions 19p, 19p that are inserted into the opening Rso. By forming the closing member 19 with a cover portion 19c that closes the opening Rso of the drainage channel Rs, and providing protrusions 19p that are inserted into the opening Rso on the lower surface of the cover portion 19c, the protrusions 19p can be locked into the opening Rso, allowing for quick and consistent installation of the closing member 19.

[0041] Figures 9 and 10 show the state before and after attaching the closure member 19 to the rod support block 16.

[0042] When attaching the closing member 19 to the rod support block 16, as shown in Figure 9, it is positioned laterally to the small-diameter portion 16s of the rod support block 16, and the closing member 19 can be attached with a single touch by simply pushing it against the small-diameter portion 16s. Figure 10 shows the state in which the closing member 19 is attached to the outer circumferential surface of the small-diameter portion 16s.

[0043] Next, the method of use and operation of the drain valve 1 according to this embodiment will be explained with reference to Figure 5 and the respective figures.

[0044] First, in non-drain mode, the valve body 14 is displaced upward from the state shown in Figure 1 by rotating the operating handle 3, separating it from the valve seat 45. As a result, the auxiliary valve 14s also displaces upward and closes the drainage channel Rs. Consequently, the main water channel R is opened, and tap water flows in the direction of arrow W shown in Figure 1, that is, from the upstream water pipe Pu to the downstream water pipe Pd, returning to normal operation.

[0045] On the other hand, in drain mode, the valve body 14 is displaced downward by rotating the operating handle 3 in the reverse direction, causing it to come into contact with the valve seat 45. As a result, the auxiliary valve 14s also displaces downward, as shown in Figure 5, opening the drain channel Rs. Consequently, the main water channel R becomes watertight, and as indicated by the arrow W in Figure 5, the tap water (residual water) downstream and the tap water (residual water) in the drain valve 1 are drained through the drain channel Rs. At this time, the ball valve 17 is displaced upward (downstream) and is restricted by the closing member 19.

[0046] Therefore, the drain valve 1 according to this embodiment has a basic configuration comprising a riser pipe section 2 composed of a single cylindrical body section 11 and a single transmission rod section 12 arranged coaxially with the cylindrical body section 11, and an inverted cup-shaped operating handle section 3 having an upper end surface section 3u and a cylindrical circumferential surface section 3f. By extending the circumferential surface section 3f downward, it overlaps with the upper end section 11u of the cylindrical body section 11, and the upper end section 12u of the transmission rod section 12 is attached to the upper end surface section 3u, and the lower end section 12d of the transmission rod section 12 is attached to the valve body section 14 that opens and closes the main water channel R. As a result, the entire drain valve is simplified both structurally and in appearance, reducing the number of parts and thus reducing parts costs and manufacturing costs, as well as making the overall size and weight smaller. Moreover, there are no exposed parts, so the drain valve can be protected from external disturbances such as wind, rain, and snow.

[0047] Although preferred embodiments have been described in detail above, the present invention is not limited to these embodiments, and the details of the configuration, shape, materials, quantity, numerical values, etc. can be arbitrarily changed, added, or deleted without departing from the spirit of the present invention.

[0048] For example, a structure in which the transmission rod portion 12 is attached to the upper end surface portion 3u in a manner that restricts relative rotation and allows for detachment can be implemented by various means having similar functions. Furthermore, although an example was shown in which the closing member 19 is integrally formed in a C-shape from synthetic resin and configured to fit into a small-diameter portion 16s formed on the outer circumference 16f of the rod support block 16, it can be implemented by various forms having similar functions. It is desirable that the closing member 19 has a cover portion 19c that closes the opening Rso of the drainage branch channel Rsr, and that protrusions 19p… are provided on the lower surface of the cover portion 19c for insertion into the opening Rso, but these are not essential components. [Industrial applicability]

[0049] The drain valve according to the present invention can be used in various types of drain valves having a riser pipe, which are installed outdoors, such as in the garden of a house in a cold region. [Explanation of symbols]

[0050] 1: Drain valve, 2: Riser pipe section, 2u: Upper end of riser pipe section, 3: Operating handle section, 3u: Upper end surface of operating handle section, 3f: Circumferential surface of operating handle section, 4: Check valve, 11: Cylindrical body section, 11u: Upper end of cylindrical body section, 12: Transmission rod section, 12u: Upper end of transmission rod section, 12d: Lower end of transmission rod section, 14: Valve body section, 15: Uneven surface, 16: Rod support block, 16f: Outer circumference of rod support block, 16s: Small diameter section formed on the outer circumference of rod support block, 17: Ball valve section, 18: Regulating section, 19: Closure member, 19c: Cover section, 19p: Protrusion inserted into the opening, R: Main channel, Rs: Drainage channel, Rsr: Drainage branch channel, Rso: Opening of drainage branch channel, Fd: Downstream side of drainage channel

Claims

1. A drain valve is provided with an operating handle at the upper end of a riser pipe, and by operating the operating handle, it switches to a drain mode, thereby draining water through a drain channel having a check valve, characterized in that the riser pipe is composed of a single cylindrical body and a single transmission rod arranged coaxially with the cylindrical body, and the operating handle is an inverted cup shape having an upper end surface and a cylindrical circumferential surface, the circumferential surface is extended downward so as to overlap the upper end of the cylindrical body, the upper end of the transmission rod is attached to the upper end surface, and the lower end of the transmission rod is attached to a valve body that opens and closes the main water channel.

2. The drain plug according to claim 1, characterized in that the transmission rod portion is detachably attached to the upper end surface portion, with its relative rotation restricted.

3. The drain valve according to claim 1, characterized in that the operating handle portion has an uneven surface formed on the outer circumferential surface of the circumferential portion to prevent slippage during operation.

4. The drain valve according to claim 1, characterized in that the transmission rod portion is supported by a rod support block through which the transmission rod portion passes and through which the drainage channel is provided.

5. The drain valve according to claim 4, characterized in that the check valve comprises a ball valve portion housed in the drain channel, a restricting portion provided on the upstream side of the drain channel to restrict the movement of the ball valve portion upstream, a drain branch channel provided between the ball valve portion displaced downstream of the drain channel and the restricting portion, and a closing member that closes the opening on the downstream side of the drain channel.

6. The drain plug according to claim 5, characterized in that the closing member is integrally formed in a C-shape from synthetic resin and is configured to be fitted into a small-diameter portion formed on the outer circumference of the rod support block.

7. The drain plug according to claim 6, characterized in that the blocking member has a cover portion that closes the opening of the drain branch passage, and the lower surface of the cover portion has a protrusion that is inserted into the opening.

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