Patent Application
20060185068
Not applicable.
Not applicable.
The present invention relates to flush valves that control the flow of water from toilet tanks to toilet bowls, and in particular, to flush valves with improved flow characteristics.
Systems for controlling the flush of toilet tank water to a toilet bowl are known, see e.g. U.S. Pat. Nos. 4,172,299 and 6,178,567. Such systems have a water inlet valve for the tank that is typically controlled by a float that senses tank water level. A flapper controls the flow of the tank water through an outlet at the bottom of the tank. Depressing the trip lever unseats the flapper so that water can empty from the tank into the bowl. As the tank water drains, the float drops with the water level in the tank, thereby triggering inlet water flow. The water level drops faster than the inlet water enters so that the flapper can drop down to reseal the outlet, and the water level in the tank can be re-established. As the tank refills, the float rises with the water and eventually closes the inlet valve to shut off the water supply.
The ability of the toilet, particularly low water consumption toilets, to operate efficiently during a flush cycle is largely a function of the pathway through which the water has to travel to exit the toilet. This pathway runs from the flush valve and through the vitreous path of the bowl. Various trapway configurations have been devised to optimize flow characteristics during the flush cycle.
Relatively little of the prior efforts to improve flush performance has been to address the impact of the tank flush valve. Conventional flush valves typically have a circular opening with a cylindrical passage leading down to the outlet of the tank, see e.g., U.S. Pat. No. 5,325,547. The cylindrical construction of such valves may create an air pocket in the flow pathway after a flush is initiated because the water in the tank narrows as it accelerates under gravity through the valve. Flush valves with non-cylindrical passageways have been devised. For example, U.S. Pat. No. 5,195,190 discloses a flush valve with a passageway in the form of conical section. The decreasing diameter of the passageway in such a valve helps reduce the volume of unwanted air. However, while an improvement, the frusto-conical passageway provides less than optimal flush efficiency.
Another part of the flush valve that can have low flow efficiency is the overflow. The overflow is used in the toilet to provide a drain passage for excess water in the tank that may arise if the water supply was not shut off in time, for example by failure of the inlet seal or the float tripping the inlet valve too late. The overflow connects to the outlet of the flush valve so that excess water can pass into the bowl and to the waste plumbing lines. Conventional overflow tubes are long upright cylinders with the lower end communicating with the main flow passage of the flush valve and the upper end extending slightly above the desired normal full water level in the tank, see e.g. U.S. Pat. No. 4,433,446. Such cylindrical overflow tubes suffer similar less than optimal flow characteristics as do the cylindrical flush valves.
U.S. Pat. Nos. 6,401,269 and 6,651,264 both disclose flush valve assemblies that have stout, rectangular overflow tubes with relatively large mouths at the upper ends and tapering walls. While the wide mouth and narrowing construction do affect flow efficiency relative to conventional cylindrical overflow tubes, the generally rectangular cross-section still provides less than ideal flow.
Thus, a need exists for a flush valve with improved flow characteristics.
The present invention provides a toilet flush valve that has improved flow characteristics resulting from a flow passage with a non-linearly narrowing flow profile which more closely follows the narrowing exhibited by falling water as it accelerates under gravity. The non-linear flow profile of the valve flow passage reduces the presence of air in the valve after a flush cycle is initiated so that greater flush efficiency can be achieved. The flush valve can also have a narrowing overflow, preferably non-linearly, to similarly improve flow in an overflow situation.
Specifically, in one form the invention provides a flush valve for controlling the flow of water from a toilet water tank. A valve body has a valve seat and a flow passage leading from the valve seat. An inner surface of the valve body that defines the flow passage such that at least a portion of the flow passage narrows non-linearly away from the valve seat. A seal can seat against the valve seat to close off the valve seat. The non-linear surface of the valve body can be computationally derived and expressed as a polynomial equation.
The valve body defines two openings at each end, one at the upper end with the valve seat and another at the lower end that attaches to the outlet of the tank. Given the narrowing of the flow passage, the lower opening is of a lesser dimension than the opening at the valve seat.
The flush valve can have a flapper seal with a hollow inner cavity and a yoke having a pair of legs (each having an opening defining the pivot axis) such that the flapper seal is pivotal with respect to the valve body. The flapper seal and/or the yoke can have an attachment site for attaching a trip connector operable to unseat the flapper seal.
The flush valve can also have an improved overflow. The overflow defines an overflow passage in communication with the flow passage of the valve body that narrows between a wide mouth upper opening of the overflow and a lower opening of the overflow. The overflow passage preferably narrows from its wide mouth for some of its length or all of the way to the lower opening in some way, such as in a funnel shape, or more preferably non-linearly. The overflow can be a separate component and permanently or removably connected to the valve body.
The advantages of the invention will be apparent from the detailed description and drawings. What follows are preferred embodiments of the present invention. To assess the full scope of the invention the claims should be looked to as the preferred embodiments are not intended as the only embodiments within the scope of the invention.
The flush valve assembly 26 is mounted vertically upright in the tank 12 and includes a valve body 28, an overflow tube 30 and a flapper seal 32. The valve body 28 and overflow 30 are preferably a non-corrosive material, such as a suitable plastic. The lower end of the valve body 28 has three prongs 36 that are used to engage an underside of the horizontal wall 16, and an outer flange 38, with a suitable gasket 40, engages an upper side of the wall 16, to mount the flush valve assembly 26 to the tank 12. This connection is similar to that disclosed in U.S. Pat. No. 4,433,446, which is assigned to the assignee of the present invention, and the disclosure of which, particularly
As shown in
As water accelerates from gravity the sectional area of the water decreases. This narrowing occurs non-linearly. The flow profile of the valve is designed to more closely follow the natural path that water takes as it falls under gravity. By forming the flow profile of the valve in this way, less air is present in the flow passage during a flush cycle. Reducing the air in the flow passage promotes a more efficient flush, since the air must otherwise be vented or entrained within the water, which reduces the flush efficiency of the toilet.
As
The profile can be computationally derived from a polynomial expression. The expression can vary to suit different parameters, such as a different axial distance between the openings 46 and 48 or different sized openings 46 and 48. In the preferred example of
wherein DU is the diameter of the upper opening 48 and DL is the diameter of the lower opening 46 and h is the length of the flow passage 44. However, as mentioned, other computational derived mathematical expressions can be employed to achieve a non-linear flow profile that is optimal for the other parameters of the valve, including such expressions of any order less then or greater than one.
In one standard size (shown in
Referring again to
The overflow 30 defines an overflow passage 58 in communication with the flow passage 44 of the valve body 28 through the channel 54 of the extension 52. The overflow 30 has a wide mouth upper opening 60 and narrows at an upper portion 62 to the cylindrical portion 58 with a lower opening 64, with circular horizontal cross-sections throughout. The inner surface of the overflow 30 at the tapered upper portion 62 preferably defines a non-linearly narrowing overflow passage so that flow benefits can be gained similar to that through the flow passage 44. Also like the flow passage 44, a suitable polynomial expression can be used to define the inner wall of the overflow to arrive at a preferred non-linearly narrowing profile.
However, since the overflow 30 is used for infrequent overflow situations where the flow rate is much less than the typical rate of a flush cycle, the upper portion of the overflow could follow a simple conical section profile, such as a funnel shape, which would be easier to manufacture and yet still provide improved performance over a straight cylindrical profile. In any event, the wide mouth of the upper opening 60 increases the perimeter distance of the overflow to permit a greater volume of excess water to transition quickly from the tank to the overflow passage 58, and then down to waste plumbing.
The upper opening 60 is preferably at least 1½ inches (3.8 cm), and in one standard size (shown in
Referring again to
Prior to performing a flush operation, the flush valve is in the position shown in
It should be appreciated that merely preferred embodiments of the invention have been described above. However, many modifications and variations to the preferred embodiments will be apparent to those skilled in the art, which will be within the spirit and scope of the invention. Therefore, the invention should not be limited to the described embodiments. To ascertain the full scope of the invention, the following claims should be referenced.
