BACKGROUND OF THE INVENTION
This invention relates to a flush valve structure for a toilet tank.
U.S. Pat. No. 6,484,327, the entire disclosure of which is hereby incorporated by reference herein for all purposes, discloses a flush valve structure for a toilet tank equipped with a spud by which the tank is connected in substantially fluid tight manner to an outlet tube that discharges into a toilet bowl.
In the valve shown in the prior patent, the seal is circular and the inner diameter of the seal is almost the same as the inner diameter of the outflow tube.
SUMMARY OF THE INVENTION
According to a first aspect of the present invention there is provided a toilet tank flush valve structure, for use with a toilet tank having a floor formed with an opening, the flush valve structure comprising a base for installation in the opening formed in the floor of the toilet tank, the base defining a water outflow passage having an upper end at which the passage has an area A1 and a lower end at which the passage has an area A2 and including a valve seat at the upper end of the water outflow passage, and a flush valve that is movable relative to the base between a sealing position in which the valve engages the valve seat in sealing relationship and a flushing position in which the valve is spaced upwardly from the valve seat, and wherein the area A1 is substantially greater than the area A2.
According to a second aspect of the present invention there is provided a toilet tank structure comprising a toilet tank having a floor formed with an opening, a flush valve base for installation in the opening in the floor of the toilet tank, the floor of the toilet tank being also formed with a valve seat that surrounds the flush valve base and defines an inlet end of a water outflow passage, the inlet end of the water outflow passage having an area A1 and the base having an outlet opening of area A2, and a flush valve that is movable relative to the base between a sealing position in which the valve engages the valve seat in sealing relationship and a flushing position in which the valve is spaced upwardly from the valve seat, and wherein the area A1 is substantially greater than the area A2.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:
FIG. 1 is a sectional view of a first flush valve structure embodying the present invention,
FIGS. 2A-2C illustrate schematically a second flush valve structure embodying the present invention,
FIG. 3 illustrates a third flush valve structure embodying the present invention,
FIG. 4 illustrates a fourth flush valve structure embodying the present invention,
FIG. 5 is a part sectional view of a fifth flush valve structure embodying the present invention,
FIGS. 6A and 6B illustrate a sixth flush valve structure embodying the present invention,
FIG. 7A is a sectional view of a seventh flush valve structure embodying the present invention,
FIGS. 7B and 7C illustrate variations on the seventh flush valve structure,
FIG. 8 is a sectional view of a ninth flush valve structure embodying the present invention, and
FIG. 9 is a sectional view of a tenth flush valve structure embodying the present invention.
In the several figures of the drawings, reference numerals having like combinations of less significant digits designate like or equivalent elements.
DETAILED DESCRIPTION
FIG. 1 shows a modular flush valve structure 100 including a base 114 that is provided with a sealing gasket 115 and is secured in the outflow hole of a toilet tank by a nut 122 in similar manner to the spud of a conventional flush valve structure. The base 114 includes an outflow tube 126 that extends downwardly from the floor 118 of the toilet tank. An upwardly flaring frusto-conical extension 128 extends upward from the base and a valve seat 130 is attached to or integrally formed with the extension 128. The valve seat is circular and has a generally triangular radial section.
A guide 134 is attached to the valve base 114 and extends vertically upward therefrom. A dual volume flush valve assembly 138 is fitted slidably over the guide and includes a high volume flush valve 142, or lower flush valve float device, and a low volume flush valve 146, or upper flush valve float device. The high volume flush valve comprises a float 150, a flexible annular gasket 154 below the float, and an upwardly flaring frusto-conical extension 158 above the float. A circular valve seat 160 is attached to or integrally formed with the extension 158 and has a generally triangular radial section. An upper outflow tube 163 extends downward from the extension 158. The high volume flush valve defines a water outflow passage that extends downward through the high volume flush valve from an opening bounded by the valve seat 160 to an opening at a lower end of the high volume flush valve. Extension 128 defines a downwardly tapering upper segment of the water outflow passage. The low volume flush valve 146 rests on the high volume flush valve 142 and includes a float 162 and a flexible gasket 166 below the float. The low volume flush valve defines a passage that extends vertically through the low volume flush valve. Normally, the seat 130 seals against the gasket 154 and the seat 160 seals against the gasket 166. The two valves are connected to an actuating mechanism (not shown), such as one or more handles, which may be operated to lift either the low volume valve 146 from the high volume valve 142, or the high volume valve 142 from the base while the low volume valve 146 rests on the high volume valve.
It will be seen from FIG. 1 that the diameter of the seal between the seat 130 and the gasket 154 is substantially greater than the diameter of the outflow tube 126. In the embodiment shown in FIG. 1, the diameter of the outflow tube may be 2 inches and the diameter of the seal between the seat 130 and gasket 154 is at least 2.5 inches. When the high volume valve 142 is raised by 1 inch from the base, the area available between the valve seat and the gasket for flow of water is about 7.86 sq. inches. It has been found through experimentation that for a given diameter of outflow tube and for a given lift of the high volume valve the valve structure shown in FIG. 1 provides a substantially more vigorous water outflow than the dual volume flush valve structure shown in the prior patent.
The frusto-conical interior surface of the extension 128 results in the cross-sectional area of the flow passage from the seat 130 to the outflow tube 126 decreasing smoothly from the circular rim of the seat to the entrance to the outflow tube.
In addition, FIG. 1 shows that the diameter of the seal between the seat 160 and the flexible gasket 166 is substantially greater than the diameter of the upper outflow tube 163. In the embodiment shown in FIG. 1, the diameter of the upper outflow tube may be 2 inches and the diameter of the seal between the seat 160 and the gasket 166 is at least 2.5 inches. When the low volume valve 146 is lifted, the outflow of water is substantially more vigorous than in the case of the dual volume flush valve structure shown in the prior patent.
FIGS. 2A-2C (referred to collectively as FIG. 2) illustrate a modification of the flush valve structure shown in FIG. 1. In the flush valve structure 200 shown in FIG. 2, the seat 230 comprises a flexible gasket and the sealing element 254 of the high volume valve 242 is essentially rigid.
The upper outflow tube 262 of the high volume valve 242 extends downward into the extension 228 and almost engages the interior surface of the extension. A small clearance remains in order to prevent interference with functioning of the valve. The downward extension of the upper outflow tube ensures that when the low volume valve 266 is lifted, and water flows downward through the extension 258 and the upper outflow tube 262, it is channeled vertically downward into the outflow tube 226.
FIG. 2B illustrates the dual volume flush valve assembly of FIG. 2 when both the low volume and the high volume valves are lifted whereas FIG. 2C illustrates the valve assembly of FIG. 2 when the low volume flush valve is lifted from the high volume valve.
FIG. 3 illustrates a third flush valve structure embodying the present invention. The flush valve structure shown in FIG. 3 is similar to that of FIG. 2 except that the outlet tube 326 of the base 314 has a 3 inch diameter rather than a 2 inch diameter. In the case of FIG. 3, the upper outflow tube 362 extends into the interior of the frusto-conical extension 328 and directs the flow of water into the lower outflow tube 326. It is not important that the lower end of the upper outflow tube 362 is spaced inwardly for the extension 328, because the diameter of the lower outflow tube 326 is sufficiently larger than the diameter of the upper outflow tube 362 that there is little tendency for reverse flow into the extension 328.
FIG. 4 illustrates a fourth flush valve structure embodying the present invention. The flush valve structure shown in FIG. 4 is similar to that of FIG. 3 except that it is a single volume flush valve structure.
FIG. 5 illustrates a fifth embodiment of the invention in which the base 514 provided with a seal 516 is fitted in a circular recess in the floor of the tank and the circular recess is surrounded by an annular plateau 518. The seat 530 is provided at the top of the annular plateau, which has a frusto-conical interior surface tapering downward towards the entry to the outflow tube 526.
A sixth embodiment of the invention is illustrated in FIGS. 6A and 6B. As shown in FIGS. 6A and 6B, the interior passage of the outflow tube 626 of the base tapers in a downward direction. In the event that the high volume flush valve is operated, and water flows into the extension 628 between the valve and seat of the high volume valve, the reduction in area of the interior passage of the outflow tube results in the flow of water being at a higher speed than if the outlet tube were of uniform cross-sectional area. The high speed water flow results in effective removal of waste from the toilet bowl. The upper outflow tube 662 is similarly provided with an insert that reduces the cross-sectional area of the interior passage of the outflow tube smoothly toward the lower end of the upper outflow tube. Accordingly, when the low volume flush valve is lifted, as shown in FIG. 6B, the water flow through the upper outflow tube is at a higher speed than if the upper outflow tube were of uniform cross-sectional area.
The flush valve assemblies shown in FIGS. 2-6 are of substantially larger horizontal extent than valve assemblies that are currently in wide use. The opening in the floor of a toilet tank that is designed to accommodate a conventional valve assembly might be so close to a wall of the tank that interference between the valve structure shown in FIGS. 2A-2C, for example, and a wall of the tank, may prevent installation of the flush valve assembly in the toilet tank in the manner illustrated in FIGS. 2A-2C. This potential limitation is avoided in the case of the embodiment shown in FIG. 7A, where the base 714, or base structure, that is fitted in the outlet opening of the tank includes a base portion installed in the opening in the floor of the toilet tank and an S-shaped offset tube 770, or offset portion, which extends upward from the base portion and positions the valve assembly with a horizontal offset from the outlet opening of the tank.
FIGS. 7B and 7C show another approach to the problem of possible interference between the flush valve assembly and a wall of the toilet tank. The valve structure shown in FIGS. 7B and 7C is similar to that shown in FIG. 2 except that the extension 728 is not frusto-conical but is skewed so that the center of the seat 754 lies over the rim of the base 714. The lower end of the guide 734 is in threaded engagement with the rim of the base 714.
An eighth embodiment of the invention is illustrated in FIG. 8. In the case of FIG. 8, the single volume flush valve includes a flexible flapper valve that pivots relative to the base 814 about a horizontal axis. The base 814 includes a frusto-conical extension 828 that flares upward and terminates in a seat 830 against which the flapper valve seals.
The ninth embodiment of the invention, shown in FIG. 9, is similar to that shown in FIG. 8 except that the outflow tube 926 decreases in cross-sectional area in the downward direction, similarly to FIG. 6.
It will be appreciated that the invention is not restricted to the particular embodiment that has been described, and that variations may be made therein without departing from the scope of the invention as defined in the appended claims, as interpreted in accordance with principles of prevailing law, including the doctrine of equivalents or any other principle that enlarges the enforceable scope of the claims beyond the literal scope. Unless the context indicates otherwise, a reference in a claim to the number of instances of an element, be it a reference to one instance or more than one instance, requires at least the stated number of instances of the element but is not intended to exclude from the scope of the claim a structure or method having more instances of that element than stated.
Patent Application
20100162477
