Title:
Pressure-assisted toilet flush cartridge
Kind Code:
A1


Abstract:
A pressure assisted toilet flush cartridge that reduces noise output by controlling water flow. One aspect of the noise reduction is to reduce the initial discharge increase in flow rate. Another aspect is to create a vortex in discharge water to reduce cavitation and quiet the discharged water flow through the bowl.



Inventors:
Martin, Raymond Bruce (Bloomfield Hills, MI, US)
Application Number:
11/156718
Publication Date:
12/21/2006
Filing Date:
06/20/2005
Assignee:
Water Control Technology Corporation
Primary Class:
International Classes:
E03D1/00
View Patent Images:
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Primary Examiner:
NGUYEN, TUAN N
Attorney, Agent or Firm:
FISHMAN STEWART PLLC (TROY, MI, US)
Claims:
What is claimed is:

1. A mechanism for initiating a flush of a pressure assisted toilet, comprising: a generally cylindrical housing having a top end, a bottom end, an internal surface and a discharge aperture having a first predetermined area; a flush valve interposed within said housing and having a top flange, a generally hollow body with a top flange opening, and a lower extension, wherein said flange and said internal surface define a generally annular gap having a second predetermined area, and wherein said first predetermined area is larger than the second predetermined area.

2. The mechanism of claim 1, wherein said flush valve further comprises a flush valve seal selectively in sealing contact with a pressure tank outlet.

3. The mechanism of claim 2, wherein said hollow body selectively contains a predetermined volume of water, and wherein said volume of water provides a motive force to assist said flush valve seal to seat with the pressure tank outlet.

4. The mechanism of claim 2, wherein said lower extension selectively extends through the pressure tank outlet.

5. The mechanism of claim 1, wherein said housing further comprises a retaining element disposed on said internal surface, wherein said retaining element interferes with said top flange to prevent said flush valve from undesirably passing through said bottom end.

6. The mechanism of claim 1, wherein said wherein said lower extension has a generally helical muffler surface.

7. The mechanism of claim 6, wherein said generally helical muffler surface comprises a helical groove formed within said lower extension.

8. The mechanism of claim 1, wherein said lower extension imparts a vortex in fluid flowing past said lower extension.

9. The mechanism of claim 1, wherein said flush valve is actuated by a decrease in pressure within said housing.

10. A flush valve for a pressure assisted toilet, comprising: an edge circumscribing a first predetermined area; a flush valve seal selectively in sealing contact with a vessel outlet; a generally hollow body connecting said edge and said valve seal and having an opening, wherein said hollow body selectively contains a predetermined volume of water, and wherein said volume of water provides a motive force to assist said flush valve seal to seat with a vessel outlet.

11. The flush valve of claim 10, further comprising a lower extension, wherein said lower extension has a generally helical muffler surface.

12. The flush valve of claim 11, wherein said generally helical muffler surface comprises a helical groove formed within said lower extension.

13. The flush valve of claim 11, wherein said generally helical muffler surface comprises a helical fin extending from said lower extension.

14. The flush valve of claim 10, wherein said flush valve is selectively interposed within an outer housing of a flush cartridge, the flush cartridge including a passageway of a second predetermined area, said edge and an internal surface of the outer housing define a generally annular gap having a third predetermined area; wherein a lower portion of said flush valve is selectively interposed within a discharge outlet, said lower portion and the discharge outlet defining a gap having a fourth predetermined area; and wherein the second predetermined area is greater than the combination of the third predetermined area and the fourth predetermined area.

15. The flush valve of claim 10, wherein said lower extension creates a vortex in fluid flowing past said lower extension.

16. A method of reducing flushing noise in a pressure assisted toilet, wherein the pressure assisted toilet includes a pressure-assisted tank, the method comprising: imparting a swirling effect in a fluid discharged from the pressure tank to create a vortex.

17. The method of claim 16, further comprising: determining an initial flow rate of water discharged from said pressure tank; and reducing the initial flow rate.

18. The method of claim 16, wherein said vortex is created outside said pressure tank.

19. The method of claim 16, further comprising: determining the a maximum flow rate of water discharged from said pressure tank; and reducing said maximum flow rate.

20. The method of claim 16, further comprising limiting the initial discharge flow rate from the pressure tank by limiting the effective area for flow of fluid as the fluid begins to flow.

21. A flush valve cartridge for a toilet comprising: an outer housing having an internal surface; a passageway having a first predetermined area to permit flow of a fluid; and a flush valve at least partially interposed within said outer housing, said flush valve including an edge and a lower portion, wherein said edge and said internal surface define a gap having a second predetermined area, said lower portion is at least partially interposed within a discharge outlet of the toilet, said lower portion and said discharge outlet defining a generally annular gap having a third predetermined area, and wherein said first predetermined area is larger than the combination of said second predetermined area and said third predetermined area.

22. The cartridge of claim 21, wherein said lower portion is selectively raised relative to the discharge outlet and said third predetermined area increases as said lower portion is selectively raised.

23. The cartridge of claim 21, wherein said flush valve further comprises a generally hollow body selectively adapted to fill with a fluid.

24. The cartridge of claim 21, further comprising a helical groove formed on said lower portion.

Description:

TECHNICAL FIELD

The present invention relates to a pressure assisted toilets, and more specifically to a flush cartridge for a pressure assisted toilet.

BACKGROUND OF THE INVENTION

A pressure assisted toilet system typically includes a vessel, a supply system and a flush cartridge. The supply system typically includes a backflow prevention and a pressure regulator to ensure that the vessel is maintained below a desired pressure. Since the vessel is fully sealed, it retains the supply pressure after each flush cycle refill. This supply pressure, typically 45-55 psi, pressurizes the pressure tank to its prescribed level and provides a motive force for a subsequent flush of a toilet bowl. Prior art pressure assisted toilet systems are found in U.S. Pat. Nos. 4,223,698, 5,361,426, and RE37,921 the disclosures of which are hereby incorporated by reference in their entireties.

FIG. 1 illustrates a prior art pressure assisted toilet system 20. System 20 is typically encased in an outer vitreous china housing 22, a vessel 24 having a discharge outlet 28 and an inlet 30, and a flush valve cartridge 36. Flush valve cartridge 36 includes a flush valve 38 having a seal 40, a top flange 42, and an escape hole 44 formed therein, a flush valve enlargement 46 interposed through and sealing with the escape hole 44, and a flush valve spring 48. Seal 40 of flush valve 38 seats against discharge outlet 28 in order to allow pressure tank 24 to fill with water. When ready to be flush, upper chamber 47 contains both water and air compressed by the pressure To flush system 20, an actuation lever urges valve enlargement 46 downward, which permits water (and air) to flow through escape hole 44, thereby reducing the pressure above flush valve 38 within cartridge 36. With this pressure reduced, flush valve 38 is forced upward by the pressure differential created between the tank 24, and the area above the flush valve. As the flush valve lifts, water is discharged through discharge outlet 28.

A disadvantage of the prior art pressure assisted toilet system is that the noise generated during flushing has restricted its use in residential applications where excessive noise is undesirable. This noise is partially due to the rapid change in water flow rate, cavitation, and flow direction. Additionally, multiple parts are required to flush prior art toilets, thus adding to the expense of these systems. What is needed, therefore, is a pressure assisted toilet system that controls the flow of water such that noise is reduced to more acceptable levels.

SUMMARY OF THE INVENTION

The present invention relates to reducing the noise output of a pressure assisted toilet. The inventor has found that reducing the rate of initial water flow during a flush and swirling the water discharge from the pressure tank to the bowl individually reduce undesirable noise, and that a combination of these two reduce noise even further when compared to units such as, for example, the U.S. Pat. No. 4,223,698 Patent.

An embodiment of the pressure assisted toilet flush cartridge includes a generally cylindrical housing having a top end, a bottom end, an internal surface and a discharge aperture having a first predetermined area. The cartridge further includes a flush valve interposed within the housing and having a top flange, a generally conical hollow body with a top flange opening, and a lower extension, where the flange and the internal surface define a generally annular gap having a second predetermined area, and where the first predetermined area is larger than the second predetermined area.

Another embodiment of the present invention provides a flush valve for a pressure assisted toilet that includes a top outer edge circumscribing a predetermined area, a flush valve seal selectively in sealing contact with a vessel outlet and a generally hollow body connecting the top outer edge and the valve seal. The body has an opening and contains a predetermined volume of water, where the volume of water provides a motive force to assist reseating the flush valve seal to seat with a vessel outlet.

A further embodiment includes method of reducing noise in a pressure assisted toilet that includes imparting a swirling effect in a fluid discharged from the pressure tank to create a vortex.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a sectional elevation view of a prior art pressure assisted flush system including the flush cartridge.

FIG. 2 is a similar sectional elevation view as in FIG. 1 except that a flush cartridge in accordance with an embodiment of the present invention has replaced the prior art version

FIG. 3 is an enlarged partial sectional elevation view of the flush cartridge of FIG. 2.

FIG. 3A is an enlarged sectional elevation of the flush cartridge of FIG. 2.

FIG. 3B is an enlarged sectional elevation view similar to FIG. 3A, illustrating an alternate embodiment of a portion of the flush cartridge.

FIG. 4 is a sectional view of a conceptual actuator cartridge for the flush cartridge of FIG. 2.

FIG. 5 is a graphical depiction of flow/volume results of a prior art flush cartridge.

FIG. 6 is a graphical depiction of flow/volume results of an embodiment of a flush cartridge of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 2 illustrates a pressure assisted toilet flush system 70 in accordance with an embodiment of the present invention. The system 70 includes a vessel, or pressure tank, 74 having a discharge outlet 78 and an inlet 80, and a flush cartridge 82. Discharge outlet 78 is preferably defined in part by a frusto-conical interior surface 84 and a generally cylindrical surface 86, as discussed below.

With reference to FIGS. 2 and 3, flush cartridge 82 includes a jacket, or outer housing, 88, a flush valve 90, and a top cap 92. Outer housing 88 includes a cylindrical body (or jacket) 94 that extends from a top end 96 to a bottom end 98, and an internal surface 100. Top end 96 defines a larger inside diameter than bottom end 98, and internal surface 100 is accordingly tapered from top end 96 to bottom end 98. Internal surface 100 includes a retaining element 104 disposed thereon and extending inwardly from the internal surface 100. Preferably, retaining element 104 is three equally spaced retaining lugs formed on the internal surface during forming of outer housing 88.

The flush valve 90 includes a seal retaining portion 108, a seal 110, a top flange 112, a generally hollow frusto-conical body 114 extending therebetween, a lower portion 116 extending below the seal 110, and a top flange opening 120 that extends from body 114 past top flange 112, thus providing a hole for filling body 114 of flush valve 90, as discussed below. Preferably, seal 110 is a conventional o-ring that is restrained within seal retaining portion 108 and extending radially therefrom in sealing contact with discharge outlet 78 when flush valve 90 is closed, as discussed in greater detail below. Top flange 112 includes a top outer edge 118 that defines a predetermined area.

A generally annular gap 122 is located between top outer edge 118 and internal surface 100. Gap 122 increases slightly as flush valve 90 rises within outer housing 88 due to the taper of internal surface 100. Gap 122 allows fluid to pass from pressure tank 74 to flush cartridge 82, as discussed below.

Lower portion 116 is illustrated with a helical groove 126 formed therein. Helical groove 126 is illustrated with a semi-circular section, although any suitable section may be formed on lower portion 116. The effective width, W of helical groove 126 increases as helical groove 126 extends away from seal retaining portion 108. As best seen in FIG. 3, helical groove 126 has an effective width W1 at the end closest to seal retaining portion 108. Helical groove 126 has an effective width W2 at about the midpoint of helical groove 126 and an effective width W3 adjacent the end that is opposite seal retaining portion 108. W3 is greater than W2, which is greater than W1. Preferably, W3 is about 50% greater than W1. Varying the size of the semi-circular passages of helical groove 126 varies both the effective area of gap 124 and the initial discharge flow rate and thus varies the rate of lift and the circularity of water into the bowl adjacent generally cylindrical surface 86, as discussed below. With reasonable extremes, the more circularity, the greater the flow noise reduction.

While body 114 is described as being frusto-conical shaped, body 114 may be any suitable shape that retains fluid and connects top flange 12 to seal retaining portion 108. Flange opening 120 allows water to enter body 114 while body 114 retains the water to provide a downward force (illustrated as D in FIGS. 2 and 3). Top cap 92 includes a top passageway 130 extending there through and connecting outer housing 88 with an actuation port 132. The actuation of flush valve 90 via actuation port 132 is discussed with reference to FIG. 4, below.

With specific reference to FIG. 3A, a generally annular gap 124 is located between generally cylindrical surface 86 and lower portion 116 adjacent width W1 of helical groove 126. Gap 124 allows water to travel from pressure tank 74 to the bowl (not shown). Gap 124 controls the discharge flow rate from pressure tank 74 as discussed in greater detail below.

The area of passageway 130 (FIG. 3) is greater than the combination of the area defined by gap 122 (FIG. 3) and the area defined by gap 124 (adjacent width W1, FIG. 3A). Preferably, the area of passageway 130 is at least 20% greater than the combination of the area defined by gap 122 and the effective area defined by gap 124.

FIG. 3A illustrates the lower portion 116 of FIG. 2 with helical groove 126. FIG. 3B illustrates an alternate embodiment where a lower portion 116′ includes a helical protrusion 126′. Helical protrusion 126′ creates an outwardly extending fin that imparts a swirling effect within the water discharged from pressure tank 74

FIG. 4 illustrates a simple actuator assembly 140. Actuator assembly 140 includes an actuator body 142 having an inlet 144, an outlet 146, a cylindrical interior surface 148, and an endcap 150. Endcap 150 has a plunger 152 extending there through and connects an actuator handle 160 with a grommet seal 162. Plunger 152 has an elastomeric cup seal 164 attached thereto with a return spring 166 extending between. Actuator handle 160 is rotatable with respect to plunger 152 via pin 170. Actuator handle 160 includes an actuation surface 172 that defines a generally equiangular spiral. That is, actuation surface 172 is curved such that distance H is greater than distance G. Inlet 144 is in fluid communication with the actuation port 132. Outlet 146 is open to the atmosphere within china housing 72 or can be connected to the vessel's outlet below seal 110. While actuator assembly 140 can be made of any suitable material, acetal plastic would be preferred.

When installed, system 70 is filled with water through inlet 80. The American National Standard mandates that the typical residential water pressure range between 20 psi to no more than 80 psi. Preferably, a pressure relief valve (not shown) is located in the water line between a water source and inlet 80 to restrict inlet water pressure to the desired pressure (usually around 25 psi). After filling, vessel 74 is pressurized to the inlet water pressure setting. This tank pressure urges seal 110 into a binding contact with discharge outlet 78 and grommet seal 162 into a binding contact with outlet 146. Since air is compressible and water is not, as vessel 74 refills after being flushed, the air within the vessel 74 and flush cartridge 82 is compressed into flush cartridge 82. During the first fill, some water will pass through gap 122 and enter body 114. When the pressure within vessel 74, flush cartridge 82, and actuation assembly 140 equalize, flow into the assembly ceases.

In operation, an operator rotates actuation handle 160 such that grommet seal 162 is unseated from outlet 146. This releases compressed fluid from actuator assembly 140 and outer housing 88 such that the pressure above flush valve 90 is reduced and falls below the pressure within vessel 74. The pressure above flush valve 90 falls below the pressure within vessel 74 because the area of passageway 130 is greater than the area defined by gap 122 plus the area defined by gap. The relationship between outlets 130 and 146 to gaps 122 &124 is critical because if their combined area is too close to equal, the flush valve's lift will be restricted causing an insufficient discharge flow rate to cause proper extraction of the water closet bowl. fluid released through outlet 146 flows into the china housing (not shown) and eventually through a drain passageway into the water closet bowl.

The greater pressure below flush valve 90 causes flush valve 90 to rise. When flush valve 90 rises, seal 110 unseats from discharge outlet 78, thereby permitting water from vessel 74 to escape through discharge outlet 78. After the majority of water within pressure tank 74 has discharged through discharge outlet 78, thereby reducing the pressure within pressure tank 74, flush valve 90 falls due to the force of gravity and seal 110 reseats on discharge outlet 78. Because the water within body 114 of flush valve 90 is retained, this creates an extra force that ensures that the flush valve falls, or returns to a seated position. Flush valve lower portion 116 ensures that the flush valve 90 remains centered for proper seating and sealing. As pressure tank 74 refills, pressure within pressure tank 74 increases, thereby ensuring a proper seat between seal 110 and discharge outlet 78, and grommet seal 162 and outlet 146.

Helical grooves 126 divert the water flowing through gap 124 into a swirling pattern, or vortex, as a portion of the flowing water flows within each helical groove 126. As flush valve 90 begins to lift from its seat on surface 84, a limited amount of water is allowed to flow through discharge outlet 78 as the effective area defined by gap 124 is limited by dimension W1 of helical grooves 126 and the clearance between surface 86 and lower portion 116. As flush valve 90 continues to rise, the effective area defined by gap 124 increases as the width of helical grooves increase, thereby permitting greater flow. This characteristic of flush valve 90 results in a gradual increase in flow of water through discharge outlet 78 as flush valve 90 rises.

As best seen in FIG. 5, a prior art flush valve, such as the flush valve disclosed in U.S. Pat. No. 4,223,698, without a helical groove formed on a lower portion, and installed on a major manufacturer's pressure-assisted bowl permits an initial spike in discharge flow that results in a maximum discharge flow of 57 gpm within 0.1 second after flushing. Of special interest is that the initial increase in flow rate of water discharged spikes as the flush valve is opened. At a tank test pressure of 50 psi and background noise level of 40 db, the operation illustrated in FIG. 5 was measured at 84.2 db.

FIG. 6 illustrates a similar flush valve with helical groove 126 formed on a lower surface extending through the discharge outlet 78 when the flush valve 90 is in the unseated position to restrain the maximum discharge flow to 46 gpm at approximately 0.2 seconds after flushing. When compared to FIG. 5, the initial increase in flow rate is more gradual, thereby reducing the flow noise. This gradual increase in flow rate is due, at least in part, to the width W1 of helical groove 126 being less than the width W3. Since the width W1 makes the effective area of gap 124 less as the flush valve 90 begins to rise, the volume of water permitted through discharge outlet 78 in about the initial second of flow is less than the volume of water permitted. Also, because of the changed relationship between inflow and outflow areas, the duration of discharge above 20 psi is extended, thus allowing improved extraction capability. At a water supply test pressure of 50 psi and background noise level of 40 db, the operation illustrated in FIG. 6 was measured at 78.0 db. The graphical representations of FIGS. 5 and 6 illustrate that the initial increase in flow rate of water discharged and existence of backpressure affect noise levels.

Additionally, the vortex imparted into the flow illustrated in FIG. 6 reduces cavitation immediately past the lower portion 116 as the pressure is reduced due to the increase in area for water flow, thereby reducing noise. Also, the vortex flow through the inner areas of the bowl (not shown) reduces noise associated with normal pressurized water flow through a pressure assisted toilet bowl.

While the invention has been described with respect to specific examples including preferred modes of carrying out the invention, those skilled in the art will appreciate that there are numerous variations and permutations of the above described systems and techniques that fall within the spirit and scope of the invention as set forth in the appended claims. Specifically, bowl tolerances and hydraulic designs may effect the overall noise levels during a flush.





 
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