Field of Search:
4/26,31,30,47,48,60,61,62,67R 138/31 137/572,576 251/144
Description:
BACKGROUND OF THE INVENTION
The present invention relates to the conservation of water resources and is concerned more particularly with the efficient use of low volumes of water in the emptying and cleaning of toilets and in other water usages.
BRIEF DESCRIPTION OF THE PRIOR ART
A variety of attempts have been made in the hopes of reducing the volume of water consumed by toilets.
These have ranged from "commercial" or "industrial" units, employing time-controlled valves, to the current, ridiculous vogue of placing dams in toilet tanks to prevent discharge of a portion of the water in the tank. This latter approach has been found to require two, three and sometimes four such reduced-volume flushings to properly remove solids and their traces from the toilet bowl.
Certain reasonably-successful arrangements have been tried in which energy is stored in the form of trapped, compressed-air volumes. This stored energy is released at the time of flushing the toilet. At best, these air-accumulators only provide a guarantee of flowrate from the tank, without concern for line-pressure loss in the pipes feeding the system.
None of the prior units has been found to be entirely satisfactory.
SUMMARY OF THE INVENTION
In general, the preferred form of the invention comprises a chamber including a main piston forming an air chamber, an internal, coaxial subchamber within and smaller than the chamber and having a sub-piston therein mounted on the main piston. Means are included for supplying water at available "line" pressure into the chamber beneath the main piston and into the sub-chamber beneath the sub-piston, while preventing loss of water from either chamber.
Each chamber is provided with its own exclusive outlet and has valves associated with the outlets.
In general, the method of my invention comprises the steps of compressing a trapped volume of air against a large piston, confining a volume of liquid against a small piston coupled to the large piston, and subsequently releasing the liquid volume to a point of use.
BRIEF DESCRIPTION OF THE DRAWINGS
A better understanding of the invention may be derived from the following description and accompanying drawings, in which:
FIG. 1 is a sectional view of the preferred form of pressure unit, and
FIG. 2 is a schematic view of the unit of FIG. 1 associated with a toilet.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in FIG. 1, the preferred form of pressure unit of the invention includes a cylindrical tank 1 having end walls 2 and 3 and defining a chamber 4.
A cylindrical sub-tank 5 extends coaxially within the tank 1 from the end wall 3 and for a major portion of the lengths of this tank 1, to form an internal sub-chamber 6.
A piston assembly 7, which includes a large piston 8 within the chamber 4 and a smaller sub-piston 9 within the sub-chamber 6, is mounted on an axial shaft or rod 10 which is free to reciprocate within this tank 1.
The piston 8 subdivides the chamber 4 into an air zone 12 adjacent the end wall 2 and a liquid zone 13 between the piston and the end wall 3.
The sub-piston 9 defines a high pressure zone 14 within the sub-chamber 6 between the sub-piston 9 and the end wall 3. The sub-tank 5 has an inlet check-valve 15 communicating with the zone 14 and the end plate 3 has an outlet 16 communicating with the zone 14. The space above the piston 9 in sub-chamber 6 is in free communication with the chamber 4.
The end plate 3 further has an inlet 17 communicating with the chamber 4 and receiving water from a supply pipe 18 via a valve 19. A drain 20 is provided in the end plate 3 to drain water from the chamber 4 and is provided with a valve 21.
It is of particular importance to my invention that the chamber 4 is to be evacuated or pressure-relieved sufficiently earlier than the evacuation of the sub-chamber 6 by the assembly. Stated another way, it is imperative that, during evacuation of the sub-chamber 6, there should be no back pressure--or, at most, minimal back pressure--on the underside of the piston 8.
To this end, I prefer to use an outlet 20 (and its piping and fittings) of a size several times larger than the size of the discharge 16 and its piping and fittings. In this way, the back pressure of the smaller discharge 16 is dominant, while the pressure-drop through the drain 20 is negligible. Therefore, when the drain 20 and discharge 16 are simultaneously released, the compressed air is free to force the piston assembly down without significant back pressure on the underside of this piston 8.
Alternatively, the water in the chamber 4 may be drained to another point of use, such as being recycled to a pump intake, well in advance of the discharge of the sub-chamber 6.
OPERATION OF PREFERRED UNIT
In operation, water at ordinary supply pressure (e.g., 40 psig) is supplied by opening the valve 19 with the valves 21 and 16a closed. Water will continue to fill the chamber 4-- and sub-chamber 6 via valve 15-- forcing the piston assembly 7 upwards and compressing the air in zone 12 until an equilibrium is reached. The valve 19 is then closed.
The drain valve 20 and discharge valve 16a may then be opened, whereupon the water in the chamber 4 is quickly drained to another point of use. The water in the sub-chamber 6, however, is forced through the outlet 16 at a multiplied pressure by the compressed air acting on the large piston 8 and applying its wide area force on the much smaller-area piston 9.
Avoiding a dissertation on hydraulics, I will generalize by pointing out that the piston 8 and sub-piston 9 can be sized to produce pressures at the discharge 16 in the order of three, four or five times the supply pressure in this intake line. The advantageous effect of such increased pressure is apparent in such services as toilet-flushing.
DESCRIPTION OF FIG. 2 EMBODIMENT
As shown in FIG. 2, the preferred form of unit is associated with a flushing toilet T. The unit of FIG. 2 is substantially similar to the unit of FIG. 1 and the parts thereof are identified by the same numerals, primed, as those used with regard to FIG. 1.
The pressure unit 1' is mounted with at least a portion of its chamber 4 at an elevation higher than the level of the flush-inlets F at the upper region of the bowl of the toilet. The flush-inlets F are supplied with water via a manifold 25 served by a pipe 26 from the drain valve 21'.
At the uppermost region of the bowl, the toilet T has a spray manifold 27 including a plurality of spray ports 28 directed against the inner surface of the bowl. The spray manifold 27 receives high pressure water from the discharge valve 16a via a pipe 29.
The valves 21', 16a' and 19' preferably are solenoid operated and controlled by a suitable sequencing means such as a timer "T" via lines 30, 31 and 32, respectively.
OPERATION OF FIG. 2 EMBODIMENT
The timer is arranged to open valve 21' for a predetermined interval before opening the valve 16a', so that the water of chamber 4' is flushed generally by gravity into the bowl through the inlets F. I prefer to include an air-bleeder check valve 33 to the chamber 4 when the chamber is to be substantially entirely emptied by gravity.
After the predetermined open period of valve 21', the high-pressure discharge valve 16a' is opened to provide a high-pressure, scouring spray against the walls of the bowl.
Upon completion of this cycle, the timer closes the valves 21' and 16a' and opens valve 19' to refill the unit 1' with a water charge. After a predetermined filling interval, the valve 19' is closed and held closed until the valves 21' and 16a' have recycled and the unit requires refilling.
It is to be understood that the particular form of timer 29 is not important to my invention. A simple cam-timer, such as used in dishwashers, would be suitable, as would a system using plain, stacked valves and dashpot delay means.
Various changes may be made in the details of the invention without sacrificing the advantages thereof or departing from the scope of the appended claims.