Flush Control System

Abstract

A flush system particularly adapted for toilets from which waste in pneumatically evacuated. A flush valve selectively admits flush fluid, under pressure, into the system. A portion of the flush fluid admitted to the system is directed into the toilet bowl to serve as a prerinse, a flush rinse and, to some extent, an after rinse; a portion is directed to actuate a soil discharge valve; and, a portion is directed to fill the reservoir compartment of an accumulator to serve as the bowl prefill for the subsequent use cycle. In both the soil discharge valve and the accumulator the flush fluid must overcome a predetermined resistance. The operation of the soil discharge valve and the accumulator are not only related to each other by virtue of their predetermined resistance to actuation in response to the pressure of the flush fluid but are also related to the period of time during which the flush valve remains open either by timing the open stage of the flush valve or by making the closure of the flush valve responsive to the pressure of the flush fluid within the system itself.

Description

BACKGROUND OF THE INVENTION

The present invention relates generally to a flush mechanism for toilets and specifically to a flush mechanism particularly adapted for use with a toilet by which waste is pneumatically evacuated thereform. A very successful pneumatic system for this purpose is disclosed in U.S. Letters Patent No. 3,663,970, and the flush mechanism of the present invention is eminently suitable for incorporation within such a system.

The system disclosed in the aforesaid U.S. Pat. No. 3,663,970 requires a certain degree of judgment, particularly in that at least a minimum volume of flush fluid must be admitted into the bowl properly to effect the flush. Moreover, there is an optimum period of time during which the soil discharge valve must remain open in such a system in order to effect not only evacuation of the bowl but also transportation of the effluent from the bowl to a holding tank or into a soil system. Closing the soil valve too soon tends to foul the system and hinder the effect operation of subsequent flush cycles. Although the problem does not exist in the system disclosed in U.S. Pat. No. 3,663,970, in those systems where the introduction of flush fluid is related to the period during which the soil discharge valve remains open keeping the valve open longer than absolutely necessary wastes flush fluid.

In addition, consistently satisfactory flush results are more assuredly achieved when the operator does not attempt to flush the toilet in a pneumatically operated system until the minimum subatmospheric pressure required to effect the flush has been attained within the system. Attempts have been made to obviate the necessity for having the operator be responsible for the existence of the necessary subatmospheric pressure preparatory to each flush by automatically sustaining the required subatmospheric pressure within the system, and while the concept of sustaining the subatmospheric pressure does preclude the necessity for operator judgment, the use of a ball valve, as disclosed in the aforesaid U.S. Pat. No. 3,663,970, militates against sustaining the desired subatmospheric pressure because the pressure differential across the ball valve tends to move it away from its seal and because the exposure of the ball tends to subject it to abuse even by so mundane an operation as cleaning the bowl.

SUMMARY OF THE INVENTION

It is, therefore, a primary object of the present invention to provide a toilet flush mechanism that is particularly adapted for use in systems which pneumatically evacuate waste from the toilet.

It is another object of the present invention to provide a flush mechanism, as above, that will provide a predetermined volume of flush fluid as a bowl prefill and is capable of admitting a substantially uniform volume of flush fluid to the bowl during, and just prior to, the actual evacuation thereof.

It is a further object of the present invention to provide a flush mechanism, as above, that will open the soil discharge valve in selected relationship to the admission of flush fluid into the system and maintain the soil discharge valve open for an optimum period of time.

It is still further object of the present invention to provide a flush mechanism, as above, in which the soil discharge valve is particularly adapted for sustaining subatmospheric pressure thereacross.

It is yet a further object of the present invention to provide a flush mechanism, as above, that utilizes relatively few moving parts and even those that do move need not be manufactured to close tolerances.

It is an even further object of the present invention to provide a flush mechanism, as above, that is quite reliable and relatively inexpensive to manufacture and maintain.

These and other objects, together with the advantages thereof over existing and prior art forms which will become apparent from the following specification, are accomplished by means hereinafter described and claimed.

In general, a flush system embodying the concept of the present invention employs a flush valve by which to effect the admission of flush fluid, under pressure, into the system. Downstream of the flush valve the pressurized flush fluid is directed to three purposes. A portion of the flush fluid is directed into the bowl as a preflush rinse; a portion is directed to open a soil discharge valve and retain it open during evacuation of the bowl; and, a portion is directed into the reservoir of an accumulator where at least a portion thereof is retained to serve as the prefill for the next use of the bowl following the actual flush and closure of the soil discharge valve.

In both the soil discharge valve and the accumulator the pressure of the flush fluid admitted to the system must overcome a predetermined resistance. In the soil discharge valve the pressure of the flush fluid must overcome a predetermined resistance to open the valve and permit evacuation of the bowl, and in the accumulator the flush fluid must overcome a predetermined resistance to fill the reservoir with at least that volume of fluid required to constitute the bowl prefill for the next use of the toilet.

It has been found that by relating the operations of the soil discharge valve and the accumulator to each other, and to the time during which the flush valve remains open, an optimum efficiency can be achieved for the flush system. In one disclosed embodiment of the flush system, the flush valve remains open for a preselected period of time, and that time period is selected in order to permit actuation of the soil discharge valve and actuation of the accumulator to be effected in response to the pressure at which the flush fluid is normally available.

In an alternative embodiment, closure of the flush valve is made directly responsive to actuation of the accumulator. The alternative embodiment also permits actuation of the soil discharge valve to be pre-established in pressure responsive relationship to the interaction between the accumulator and the flush valve.

One preferred embodiment of a flush system embodying the concept of the present invention, in conjunction with two alternative embodiments of a flush valve, are shown by way of example in the accompanying drawings and described in detail without attempting to show all of the various forms and modifications in which the invention might be embodied; the invention being measured by the appended claims and not by the details of the specification.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a flush system embodying the concept of the present invention;

FIG. 2 is an enlarged view taken substantially along line 2--2 of FIG. 1 depicting the toilet bowl represented in FIG. 1 in section and further depicting, in side elevation, a flush valve and a soil discharge valve;

FIG. 3 is an enlarged, vertical section through a soil discharge valve taken substantially on line 3--3 of FIG. 1 and further depicting, in elevation, a source of biasing pressure by which the soil discharge valve is continuously urged to the closed position;

FIG. 4 is an enlarged, horizontal section through an accumulator taken substantially on line 4--4 of FIG. 1;

FIG. 5 is an enlarged, vertical section through a flush valve taken substantially on line 5--5 of FIG. 2; and,

FIG. 6 is a vertical section through an alternative form of flush valve, the interaction of the trip mechanism associated with said flush valve being schematically represented in conjunction with an accumulator.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring more particularly to the drawings, a flush mechanism embodying the concept of the present invention is designated generally by the numeral 10 on the attached drawings and is depicted as being incorporated in a toilet assembly 11.

The toilet assembly 11 is of the type commonly referred to as a "trapless" toilet that has a bowl portion 12, the inner surface 13 of which curves convergingly downwardly from the rim 14 in the conventional fashion to a drain 15.

An elbow soil discharge valve 20 is operative to open and close the drain 15 and effect a seal between the ambient atmospheric pressure present within the bowl portion 12 communicating with the inlet port 21 of the valve 20 and the subatmospheric pressure applied to that portion of the system communicating with the exhaust port 22 of valve 20.

As best seen in FIGS. 2 and 3, the axis 23 of the inlet port 21 is oriented at a right angle with respect to the axis 24 of the exhaust port 22, and the two ports selectively communicate with each other across a first diaphragm compartment 25 within the housing 26 of the soil discharge valve 20. A circumferential anchor bead 28 on the flexible first diaphragm 29 is sealed between an annular groove 30 in the base portion 31 of the housing 26 and an opposed groove 32 in an extension component 33 secured to the base portion 31, as by a plurality of nut and bolt combinations 34. The first diaphragm compartment 25 is defined by a cavity formed between the juxtaposed base portion 31 and extension component 33.

An end cap 35 is secured to the extension component 33, as by plurality of nut and bolt combinations 36, to form a second diaphragm compartment 38 in spaced relation with respect to the first diaphragm compartment 25. A circumferential anchor bead 39 on the flexible second diaphragm 40 is sealed between an annular groove 41 in the extension component 33 and an opposed groove 42 in the end cap 35.

A connecting rod 43 is received for reciprocating movement through a bore 44 in the central portion of the extension component 33 with one end of the rod 43 being secured to the nave portion 45 of the first diaphragm 29 and the opposite end being secured to the nave portion 46 of the second diaphragm 40. For example, a bolt 47 may be secured within a cup 48 provided in the nave portion 45 of the first diaphragm 29, and a similar bolt 49 may be secured within an opposed cup 50 provided in the nave portion 46 of the second diaphragm 40. The opposite ends of the connecting rod 43 may then be threadably connected to the respective bolts 47 and 49. An annular recess 51 is provided along the axial extent of bore 44 to receive a ring seal 52 by which to preclude communication between the diaphragm compartments 25 and 38 along the connecting rod 43.

The second diaphragm 40 divides the second diaphragm compartment 38 into a first and second chamber 53 and 54, respectively. A biasing means is operative within the first chamber 53 normally to maintain the first diaphragm 29 in sealed relationship against the anvil 55 presented by the intersection of the adjacent portions of the cylindrical walls 56 and 58 which define the inlet and exhaust ports 21 and 22, respectively.

The biasing means may well comprise a spring, not shown, interposed between the second diaphragm 40 and the end cap 35 or a pressurized fluid such as Nitrogen provided from a supply cylinder 59 that communicates with the first chamber 53 through a conduit 60. When pressurized fluid is utilized it may be presented at a predetermined pressure from supply cylinder 59, or a regulator 61 may be provided along the conduit 60 in order to permit selective predetermination of the biasing pressure within the first chamber 53 for a purpose more fully hereinafter explained.

In any event, the biasing pressure within the first chamber 53 as well as the subatmospheric pressure applied by the system to the exhaust port 22 combines to compound the sealing effect of the first diaphragm 29 against anvil 55 and thereby makes the construction of the soil discharge valve 20 eminently suitable for use in a system that transports waste by pneumatic pressure.

The exhaust port 22 of the soil discharge valve 20 communicates with the inlet 64 of an air entraining drop well 65 (FIG. 1). In order to entrain sufficient air within the effluent it is highly desirable that the drop well 65 be of sufficient magnitude to allow a dispersion of the effluent as it leaves the soil discharge valve 20. For example, the exhaust port 22 may comfortably be approximately 2 inches in diameter, and in relation to an exhaust port 22 of that size the internal diameter of the drop well 65 would preferably be on the order of 3 to 5 inches.

The outlet 66 of the drop well is in the nature of an orifice that is preferably oriented at substantially a right angle with respect to the vertical axis (may comprise an extension of axis 24) of the drop well 65. To ensure sufficient entrainment of air into the effluent as it passes between the soil discharge valve 20 and orifice outlet 66 it has been found that the outlet 66 should be spaced well below the inlet 64 of the drop well 65. Continuing the aforesaid example, the orifice means works most satisfactorily when spaced at least 3 to 4 inches below the inlet 64.

At this point it should be emphasized that the internal diameter of the orifice outlet 66 and the soil conduit 68 may be relatively small by comparison to the internal diameter of piping used in conventional soil systems. For example, it has been found to be quite satisfactory if the internal diameter of the orifice outlet 66 is only on the order of one inch and the internal diameter of the soil conduit 68 is only on the order of one and one quarter inches.

The relatively small diameter of the orifice outlet 66, and its angular disposition with respect to the axis of the drop well 65, contribute not only to the efficiency with which the effluent is fragmentized but also to the desired high velocity with which the fragmentized effluent is discharged into the soil conduit 68. The internal diameter of the outlet 66 must not be so small, however, that the system will tend to jam. The suggested one inch diameter has been found to provide a satisfactory balance between these antipodal criteria.

The soil conduit 68 may communicate with a holding tank (not shown), as suggested for the pnuematic system disclosed in U.S. Pat. No. 3,663,970, or the soil conduit may communicate with a collecting tank 70 on the inlet side of a pump 71 capable of pumping the fragmentized effluent as well as effecting and maintaining a subatmospheric pressure within the collecting tank 70 and back through the soil conduit 68 and drop well 65 to the soil discharge valve 20. It should be appreciated that a plurality of toilet assemblies 11 may empty into a single collecting tank 70.

Flush water is preferably introduced into the bowl around the upper rim thereof. As depicted in FIG. 2, the upper rim 14 of the toilet assembly 11 may be provided with a passageway 76 that is connected to a water supply more fully hereinafter described. Although the flush fluid may be admitted through a single aperture, in the embodiment depicted a plurality of apertures 78 pierce the lower side of the rim 14 adjacent the inner surface 13 of the bowl portion 12 to admit the flush fluid -- e.g., fresh water.

The source of the flush fluid may well constitute a pressurized water line 79 such as is available in most urban homes. The water line 79 is secured to the inlet port of a flush valve 80.

As shown in FIG. 5, the inlet port 81 is presented from the valve housing 82 and communicates directly with an upper, or inlet, chamber 83. An outlet port 84 is also presented from the valve housing 82 and communicates directly with a lower, or outlet, chamber 85. A bonnet 86 is received through the access opening 88 in the valve housing 82 and extends across the inlet chamber 83. A bonnet ring 89 secures the bonnet 86 to the housing 82. That end of the bonnet 86 within the housing 82 presents a conical sealing member 90 that cooperatively engages a seat 91 on the partition flange 92 to separate the inlet and outlet chambers 83 and 85. A valve stem 93 is slidably received within the bonnet 86 for reciprocating movement. A disc seal 94 is mounted on the valve stem 93 and is supported by a backing assembly 95 secured to the valve stem 93, as by lock nut 96. A spring 97 biases the seal 94 into engagement with a seat 98 presented about the radially intermost edge of the conical sealing member 90.

A cap 99 is secured to the upper end of the valve stem 93 so that the application of manual pressure thereto can overcome the biasing action of spring 97 to move the seal 94 out of engagement with seat 98. A plurality of apertures 100 connect the inlet chamber 83 to a passageway 101 defined by the dimensional differential between the inner diameter of the bonnet 86 and the outer diameter of the valve stem 93. As a result, when the seal 94 is moved out of engagement with the seat 98 the flush fluid will flow from the inlet chamber 83, through passageways 101 and into the outlet chamber 85.

The full open position of the flush valve 80 may be signalled by cooperative interaction of the cap 99 with the bonnet ring 89. For example, the cap 99 may be provided with a skirt portion 102 that circumscribes an upwardly directed cylindrical extension 103 of the bonnet ring 89. The full open position of the flush valve will be signalled when the skirt portion 102 bottoms against an upwardly directed stop shoulder 104 presented from the bonnet ring 89. In addition, if the skirt portion of 102 and the bonnet ring extension 103 are dimensioned for sliding engagement, their interaction will cooperate to assure that the valve stem 93 will be subjected solely to axial actuating forces irrespective of the manner in which manual pressure is applied to the cap 99.

Although it has proven moderately acceptable for the operator to determine the length of time for the flush valve 80 to remain open, it may be even more expeditous to extend the valve stem 93 across the outlet chamber 85, through the housing 82 and into a dashpot 105. As depicted, the valve stem 93 is secured to a piston 106 slidably received to within the dash-pot cylinder 108. The cylinder 108 is shown to be threadably mounted to the housing 82 in order that the axial location of the air holes 109 may be selectively disposed with respect to the movement of the piston 106, thereby permitting a predetermination as to the distance through which -- and therefore the period of time during which -- the piston will move against the air escaping from the dashpot through restricted orifice 110.

The outlet port 84 of the flush valve 80 is connected to a manifold 115 (FIG. 1) which directs the flush fluid from downstream with respcet to the flush valve 80 into three conduits. One conduit 116 connects the manifold to the passageway 76 within the upper rim 14 of the bowl portion 12.

The second conduit 118 connects the manifold 115 to the second chamber 54 of the second diaphragm compartment 38 within the soil discharge valve 20 for a purpose more fully to be understood in conjunction with the explanation as to the operation of the present flush mechanism 10.

The third conduit 119 connects the manifold 115 to an accumulator assembly 120. As best seen in FIG. 4 the accumulator assembly 120 employs a rigid, impervious, cylindrical housing 121 having a base portion 121A and a cap portion 121B. The base and cap portion 121A and 121B present annular, radially extending flanges 122 and 123, respectively, which are juxtapositionable to facilitate joining the two portions 121A and 121B. A plurality of nut and bolt combinations 124 may serve as suitable means for effecting the joinder.

A plunger assembly 125 divides the interior of the accumulator 120 into a reservoir compartment 126 and a closed compartment 128. The third conduit 119 connects the manifold 115 to the reservoir compartment 126.

The plunger assembly 125 may comprise a bellows and piston combination. Specifically, an annular recess 129 in flange 122 is opposed by a corresponding annular recess 130 in flange 123 to anchor the mounting bead 131 of a bellows 132 that is made of flexible material to permit introversion thereof between the charged and discharged positions depicted by the chainline and full line representations, respectively, depicted in FIG. 4.

A piston 133 is slidably received within the closed compartment 128 of accumulator housing 121. The head portion 134 of the piston 133 engages the closed end portion 135 of the bellows 132 and the engaged portions are preferably maintained in contact by a retainer 136 which overlies the engaged closed end portion 135 of bellows 132 and the head portion 134 of the piston 133. The retainer 136 is secured in position by resilient flange means 138 that grippingly embraces the cylindrical body portion 139 of the piston 133 through the bellows 132.

The outer diameter of the body portion 139 and the inner diameter of the housing 121 are selected to afford a space 140 within which the bellows 132 may be introverted, as shown in FIG. 4, and at the end of the body portion 139 most remote from the head portion 134 a circumferential wiper flange 141 extends radially outwardly of the piston slidably to engage the inner surface 142 of housing 121 and thereby stabilize the piston 133 as it moves within the closed compartment 128. This stability may be further enhanced by employing an aligning guide in the form of an axial stem 145 that is secured to the piston 133 to be slidably received within the sleeve 146 secured to the end wall 148 of the base portion 121A.

That side of the bellows 132 defining the closed compartment 128 shall be termed the dry side of the accumulator assembly 120 because the flush fluid does not gain admission thereto. The opposite side of the bellows 132 -- i.e., the reservoir compartment 126 -- shall be termed the wet side of the accumulator assembly 120 because it stores the flush fluid received via the conduit 119 from the manifold 115.

Having now provided the foregoing basic description of the major components in a preferred embodiment of a flush mechanism 10, a brief description of its operation (during which additional structural details will be disclosed, as required) will assure a complete understanding of the concept embodied therein.

Initiation of the flush cycle is occasioned when the cap 99 is depressed to open the flush valve 80. The flush water will enter from the water line 79, through the valve 80 and into the manifold 115 from which it will be directed through the three conduits 116, 118 and 119.

It will be assumed that the fluid pressure available in line 79 is on the order of 80 pounds per square inch and that the flush valve 80 is of sufficient size to admit approximately 25 ounces of flush fluid per second. Flow through conduit 116 is restricted solely by the rate by which fluid can be emitted from the apertures 78 that pierce the lower side of the rim 14. The flow of preflush fluid through apertures 78 begins slowly and increases in response to the pressure applied to passageway 76, but even in response to full line pressure the flow emitted from apertures 78 should preferably not exceed approximately 6 ounces per second.

Simultaneously with the beginning preflush flow through apertures 78 the flush fluid will not only enter the second chamber 54 in soil discharge valve 20 through conduit 118 but will also enter the reservoir compartment 126 in accumulator assembly 120 through conduit 119.

The flush fluid entering the reservoir compartment 126 forces the plunger assembly 125 to compress the air within the closed compartment 128. The base edge 143 on the cylindrical body portion 139 of piston 133 bottoms against the stop ledge 144 in base portion 121A of accumulator assembly 120 to limit the compressibility of the air, or other fluid, within the closed compartment 128 and determine the maximum volumetric capacity of the reservoir compartment 126. Continuing the assumption that the pressure of the flush fluid available from line 79 is on the order of 80 pounds per square inch, it has been found to be quite satisfactory if the piston 133 bottoms against the stop ledge 144 after the air pressure within the closed compartment 128 reaches approximately 20 pounds per square inch.

As soon as the piston 133 bottoms against the stop ledge 144 the pressure in the reservoir compartment 126 will rather quickly approach the pressure in feed line 79 and at the same time the pressure in chamber 54 of the soil discharge valve 20 will reach a comparable pressure.

The opening of the soil discharge valve 20 is accomplished when the pressure applied by chamber 54 against the diaphragm 40 exceeds the opposing force applied by the biasing means -- i.e., the pressure in chamber 53 -- and any pressure differential across diaphragm 29 occasioned by the subatmospheric pressure applied to port 22. For consistently satisfactory results a subatmospheric pressure on the order of 10 inches of mercury should be applied by pump 71 to the collecting tank 70 and back through the soil conduit 68 and drop well 65 to the port 22 of the soil discharge valve 20. Thus, the precise moment at which the soil discharge valve opens during the flush cycle may be predetermined by regulating the biasing pressure applied to diaphragm 40 from chamber 53.

In order that the flush cycle need not be unduly protracted, the soil discharge valve may advantageously be opened at such time as the piston 133 bottoms in the base portion 121A of the accumulator assembly 120. According to this criterion the soil discharge valve 20 may be regulated to open in response to the application of approximately 20 pounds per square inch pressure in chamber 54. With the soil discharge valve 20 so opened, the agglomerated effluent is discharged into the drop well 65 and fragmentized as it is pulsatingly discharged through the orifice opening of outlet 66, much like the result effected by the apparatus disclosed in U.S. Pat. No. 3,663,970.

From the moment that the flush is initiated by depressing the cap 99 on the flush valve 80 approximately 1.5 to 2.0 seconds elapse before the contents of the bowl have been evacuated through the soil discharge valve 20. As such, the flush valve 80 may well be of a construction that requires the operator to maintain the cap 99 depressed until the bowl is evacuated. On the other hand, the valve 80 may incorporate a dashpot 105 in order to effect a timed delay to the closing of the flush valve 80.

In an alternative embodiment of the flush valve, identified by the numeral 180 in FIG. 6, the inlet port 181 is presented from the valve housing 182 and communicates directly with an inlet chamber 183. The outlet port 184 is also presented from the valve housing 182 and communicates directly with an outlet chamber 185. A combined bonnet and bonnet ring 187 is secured to the access opening (not shown) in housing 182 in the customary fashion. A valve stem 193 is slidably received within the combined bonnet and bonnet ring 187 and carries a disc seal 194 that cooperatively engages a seat 198 that circumscribes a passageway 197 that the partition wall 192 which separates the inlet and outlet chambers 183 and 185.

The valve stem 193 extends completely across both the inlet and outlet chambers 183 and 185, respectively, within the housing 182. That end of the valve stem 193 which protrudes through the combined bonnet and bonnet ring 187 presents a cap 199 that is secured thereto. The opposite end of the valve stem 193 extends slidably through the base wall 200 of the inlet chamber 183 in the housing 182 and terminates in a neutral pressure chamber 201 closed to the fluid in the inlet chamber 183 by virtue of the seal ring 202 through which the valve stem 193 slides. By thus terminating the valve stem 193 out of communication with the inlet chamber 183 and by not employing any additional means to bias the valve stem 193, the flush valve 180 is bistable and will reamin either in the opened or closed condition unless acted upon by an outside influence.

Accordingly, a trip mechanism 205 may be associated with the valve 180 in order to achieve a closure of the valve in direct response to the condition of the accumulator assembly 120. In this way the flush cycle need not be dependent upon the judgment of the operator and need not be the rigid function of a timed response, but rather, may vary in response to the conditions within the system itself.

The trip mechanism 205 employs a cylinder 206 in which a double acting piston 208 is slidably received. A piston rod 209 extends outwardly from the piston 208 in axial alignment with the valve stem 193 and is slidably received through the lowermost wall 210 of housing 182. A seal 211 obviates communication between the neutral pressure chamber 201 and the adjacent, first work chamber 212 in cylinder 206. The first work chamber 212 does, however, communicate with the closed compartment 128 in the accumulator assembly 120, as by conduit 213. The second work chamber 214 in the trip mechanism 205 communicates with the reservoir compartment 126 in the accumulator assembly 120, as by conduit 216. Because of this arrangement, the flush valve 180 will close in response to the system itself.

Specifically, when the flush cycle is initiated by depressing the cap 199, the flush fluid will flow past the seal 194 and through the passageway 197. The bistability of the valve 180 holds its open until some external closing force is applied.

During the time it takes the flush fluid to fill the reservoir compartment 126 of the accumulator assembly 120 the pressure in the reservoir and closed compartments 126 and 128 increase at substantially the same rate. As such, the pressure applied against the opposed work faces 218 and 219 of the piston 208, coupled with the biasing pressure of the preloading spring 220, maintains the piston rod 209 in its retracted position. However, as soon as the piston 133 in the accumulator assembly 120 bottoms, the pressure in the reservoir compartment 126 increases rapidly beyond that in the closed compartment 128, and the resulting pressure differential across the piston 208 in the trip mechanism 205 applies a greater force to the work face 219, thereby extending the piston rod 209 against the valve stem 193 to drive the disc seal 194 against its seat 198 to close the valve 180.

Irrespective of the configuration employed for the flush valve, once the flush valve is closed the flush fluid within the system will exit through the apertures 78 in the rim 14. The pressure of the flush fluid within the system will be correspondingly reduced, and when the pressure in chamber 54 of the soil discharge valve 20 is reduced below the biasing pressure applied in chamber 53, the soil discharge valve 20 will close in response to the pressure differential across the diaphragm 40. The flush fluid flowing through the bowl after the flush valve 80 closes but before the soil discharge valve 20 closes constitutes the after rinse.

As will be recalled, it is desirable that the biasing pressure in chamber 53 be such that the soil discharge valve 20 was opened in response to approximately 20 pounds per square inch pressure in chamber 54. Thus, when the pressure in chamber 54 is reduced to approximately that amount, the soil discharge valve will close at substantially the same time as the pressure in the reservoir compartment 126 of the accumulator assembly 120 equals the pressure in the closed compartment 128 thereof.

At the instant the equalization of the pressures in compartments 126 and 128 occurrs, the piston 133 is still bottomed against the stop ledge 144 in the base portion 121A of the accumulator assembly 120, and the volume of water remaining in the reservoir compartment 126 is available after the soil discharge valve 20 closes to constitute the bowl prefill for the next usage of the toilet. This volume may be adapted to the particular sewage system with which the toilet is operated, but for the majority of systems presently in operation a volume of up to 32 ounces should certainly suffice. The biasing effect of the captured air pressure within the closed compartment 128 against the plunger assembly 125 forces the fluid in reservoir compartment 126 to flow outwardly, via conduit 119, into the manifold 115 and through conduit 116 to passageway 76 in rim 14 from which it enters the bowl portion 12 by apertures 78. It may also be desirable to provide a modest biasing means in the form of a spring 149 to assist in that movement of the plunger assembly 125 required to discharge the flush fluid from the reservoir compartment 126. A biasing pressure equivalent to approximately one pound per square inch applied by spring 149 has been found sufficient to overcome any tendency for frictional restraint to impede the discharging movement of the plunger assembly 125.

A flush mechanism embodying the concept of the present invention will thereby automatically recycle in preparation for successive flushes and otherwise accomplish the objects of the invention.

Claims

What is claimed is:

1. A flush system comprising; a toilet having a bowl portion and a drain, a flush valve, conduit means to direct flush fluid from downstream with respect to said flush valve into the bowl portion of said toilet, a soil discharge valve selectively to open and close said drain, means to open and close said soil discharge valve in response to the pressure of the flush fluid in said system, an accumulator, a plunger assembly in the form of a piston and a bellows, said bellows being secured within said accumulator to divide said accumulator into a reservoir compartment and a closed compartment and to effect a seal therebetween, said piston being movable within said accumulator to delineate the volumetric capacity of said reservoir compartment, means to conduct flush fluid from downstream with respect to said flush valve into said reservoir compartment and from said reservoir compartment into the bowl portion of said toilet, and means within said closed compartment resiliently biasing said plunger assembly to discharge the flush from said reservoir compartment.

2. A flush system, as set forth in claim 1, in which said soil discharge valve comprises; a first diaphragm compartment, an inlet and exhaust port communicating with each other across said diaphragm compartment, an anvil means located in said first diaphragm compartment between said inlet and exhaust ports, a diaphragm secured within said first diaphragm compartment, a second diaphragm compartment, a second diaphragm secured within said second diaphragm compartment to define a first and second chamber in said second diaphragm compartment, means connecting said first diaphragm to move in response to movement of said second diaphragm, conduit means to direct flush fluid from downstream with respect to said flush valve into said second chamber, and means in said first chamber to apply a continuously biasing pressure against said second diaphragm.

3. A flush system, as set forth in claim 2, further comprising; a source of fluid pressure, and conduit means connecting said source of fluid pressure to said first chamber.

4. A flush system, as set forth in claim 3, in which regulating means are provided for determining the biasing pressure admitted into said first chamber.

5. A flush system, as set forth in claim 1, in which the means resiliently biasing said plunger assembly applies a lesser force to said plunger assembly than the flush fluid admitted to the system from said flush valve and in which means are provided to limit the movement of said plunger assembly and thereby determine the maximum volumetric capacity of said reservoir compartment.

6. A flush system, as set forth in claim 5, in which the means resiliently biasing said plunger assembly comprises a closed compartment containing a compressible fluid.

7. A flush system, as set forth in claim 1, in which said piston is slidable in the closed compartment side of said bellows and has a skirt means that engages a stop ledge to limit the compressibility of the fluid within said closed compartment and determine the maximum volumetric capacity of said reservoir compartment.

8. A flush system, as set forth in claim 1, in which said flush valve is bistable and in which a trip mechanism effects closure of said flush valve, said trip mechanism being actuated in response to said accumulator.

9. A flush system, as set forth in claim 6, in which said flush valve is bistable and in which a trip mechanism effects closure of said flush valve, said trip mechanism being actuated in response to the pressure differential between the reservoir and closed compartments in said accumulator.

10. A flush system, as set forth in claim 9, in which the flush valve employs a seal means mounted on a valve stem for movement therewith, and a seat, movement of said seal away from and into engagement with said seat respectively effecting opening and closing of said flush valve, and in which said trip mechanism has a means to engage and move said valve stem to close the flush valve, a piston in said trip mechanism actuates the means to engage said valve stem, said piston being of the double acting variety and being interposed between two work chambers in said trip mechanism, the application of pressure to the first of said work chambers tends to drive said piston so as to actuate the means to engage and move said valve stem to close the flush valve, said first work chamber communicating with the reservoir compartment in said accumulator, the other said work chamber communicating with the closed compartment in said accumulator.

11. A flush system, as set forth in claim 1, in which means are provided continuously to bias said flush valve to the closed position and in which a dashpot is provided to delay closure of said flush valve for a predetermined period of time.