US3654955A

US3654955A - Kinetic energy cisterns

Info

Publication number: US3654955A
Application number: US96178A
Authority: US
Inventors: Ronald John Roach; Graham George Mitchell
Original assignee: Gramall Industries Pty Ltd
Current assignee: Gramall Industries Pty Ltd
Priority date: 1969-12-11
Filing date: 1970-12-08
Publication date: 1972-04-11
Anticipated expiration: 1989-04-11
Also published as: CA924990A

Abstract

A cistern for connecting to a low pressure hot water supply network containing two float valves, one float valve being positioned above an ejector contained within the cistern and arranged to eject water from the cistern upon opening of that float valve to thereby further lower water level and open that float valve still further, so that kinetic energy of flow of discharge from the float valve is utilised in lieu of elevation of the cistern to provide head for hot water flow, the second float valve being arranged to discharge directly into the cistern after the first has partially opened to thereby prevent hunting of the first float valve.

Description

United States Patent Roach et a1.

[54] KINETIC ENERGY CISTERNS [72] Inventors: Ronald John Roach; Graham George Mitchell, both of Blair Athol, Australia [73] Assignee: Gramall Industries Proprietary Limited,

Blair Athol, Australia [22] Filed: Dec. 8, 1970 211 App1.No.: 96,178

[30] Foreign Application Priority Data Dec. 11, 1969 Australia ..6S124/69 [52] U.S. Cl ..137/423 [51] Int. Cl ..F16k 31/28 [58] Field olSearch ..l37/409, 386,416, 423,428,

[451 Apr.l1, 1972 Primary Examiner-Henry T. Klinksiek Assistant Examiner-David R. Matthews Attorney-Oldham & Oldham [5 7] ABSTRACT A cistern for connecting to a low pressure hot water supply network containing two float valves, one float valve being positioned above an ejector contained within the cistern and arranged to eject water from the cistern upon opening of that float valve to thereby further lower water level and open that float valve still further, so that kinetic energy of flow of discharge from the float valve is utilised in lieu of elevation of the cistern to provide head for hot water flow, the second float valve being arranged to discharge directly into the cistern after the first has partially opened to thereby prevent hunting of the first float valve.

5 Claims, 4 Drawing Figures PATENTEBAPR 11 m2 3.654.955

' sum 1 er 2 KINETIC ENERGY CISTERNS This invention relates to a cistern of the type wherein kinetic energy of discharge from a float controlled valve is utilized in lieu of pressure to provide a high rate of water flow in a water network, for example a hot water supply network.

In the conventional low pressure hot water network it is customary to use a cistern positioned several feet above the highest of the outlet openings of the network so that a head of water exists which provides necessary flow rate. In our Australian Patent No. 289,998 a cistern of another type is described wherein the kinetic energy of discharge from a float controlled valve is employed to provide the required flow rate, and this has the great advantage of enabling the cistern to be positioned, for example, immediately on top of a hot water storage tank. It is found in practice that under average conditions to be expected the rate of flow from a float controlled valve is sufficient to induce a flow of water from the cistern, in turn dropping the water level and still further increasing flow rate. If the intake of water flow from the cistern is through a high efficiency ejector, it is possible under extreme conditions to burst a hot water storage tank made from light gauge metal. It is therefore necessary to limit the efiiciency of the outlet fitting of the cistern which functions as the ejector so that the ejector is capable of drawing not less than inches of mercury and not more than 15 inches of mercury on normal water flow when the float controlled valve is fully open. This inefficient ejector also avoids the possibility of auto-circulation.

Commonly used ball valves which are most satisfactory are each provided with a sliding piston which is operated by a ball cam mechanism, the piston moving to a closure position against a valve face when the ball float rises and moving to an open position away from the valve face when the ball float falls, thus allowing water to flow inwardly into the cistern to again raise the level until the valve is closed. When the valve is partly open the water is deflected by the end face of the valve member and a force is applied thereto due to the change of direction of the water, and this force tends to urge the valve member to move further into the open position. As the valve opens further the ball is urged more into the water against its own buoyancy, until the water level rises owing to excess of supply over demand, whereupon the valve tends to close as the float rises. In closing however the mass of water flowing per minute is reduced and therefore the thrust tending to urge the valve member open is also reduced, and the valve member therefore moves further inwardly than it would if the mass flow rate were unaltered. In other words the valve tends to hunt when in a partly open position, and that is the position in which it would be used under normal circumstances. This hunting results in irregular supplies of water, and although in most instances this is of little consequence, if the cistern is coupled to a shower the hunting results in discomfort to the user.

The main object of this invention is to provide means whereby hunting can be avoided and at the same time a satisfactory air break can be supplied.

In one form the invention consists of a cistern comprising a container having a base and side walls, a water outlet fitting in the base (or in a side wall near the base), the outlet fitting having an internal conduit with three openings (at least) in water flow communication with one another, including an outlet opening directed outwardly from the container, a first inlet opening in alignment with the outlet opening, and a second inlet opening in communication with the space in the lower portion of the container, a first float controlled valve in the container, a conduit extending between the discharge opening of said first valve and said first inlet opening, a second float controlled valve in the container, and pipe connection means on the inlet ends of each said valve connectable with a high pressure water supply, so constructed and arranged that upon initial outward water flow from the outlet opening, the water level in the container drops and the first float controlled valve opens whereupon water flow through said outlet fitting induces water flow from the container thereby further dropping the water level whereupon said second float controlled valve opens.

It is found that tendency to hunt is substantially reduced by utilising a second valve, if the second valve is arranged to open after the first. Thus rapid drop of water level is restrained due to discharge of the second valve, resulting in a more stable water level and in turn substantially avoiding fluctuations of position of the first valve. This result is surprising and unexpected since at first sight partial closure of the second valve which occurs during hunting would appear to result in faster discharge through the second valve thus further closing the first valve. In practice however it is found that the first effect far outweighs the second effect and the invention makes possible a simple and inexpensive means for avoidance of hunting.

An embodiment of the invention is described hereunder in some detail with reference to and is illustrated in the accompanying drawings in which:

FIG. 1 is a diagrammatic elevational view of a hot water installation including a hot water outlet network,

FIG. 2 is a top view of a cistern with its cover removed,

FIG. 3 is a section taken on line 3-3 of FIG. 2, and

FIG. 4 is an enlarged section showing the mechanism of the first float controlled valve and the outlet fitting.

In FIG. 1 a hot water outlet network 10 is connected to the top of a hot water container 11, the hot water container 11 being fed from a mains water supply 12 through a cistern 13.

The cistern 13 comprises a container having a base 16 and side walls 17, and a water outlet fitting 18 passing through the base 16, although of course it may be arranged to pass through a side wall 17 near the base if this is desired.

The water outlet fitting 18 is provided with an internal conduit 20 (FIG. 4), the internal conduit 20 having three openings which are in water flow communication with one another and which include an outlet opening 21, a first inlet opening 22 which is aligned with the outlet opening and a second inlet opening 23. In the cistern illustrated the fitting 18 is in the form of a simple T member, this providing a satisfactory range of pressure ejection in a mains water pressure supply system which varies between fifty and one hundred and fifty pounds per square inch. The fitting 18 however will need to more nearly approximate an ejector shape of higher efficiency if the mains supply pressure varies, say between l5 and 50 p.s.i. pressure. It will be clear to those skilled in the art, after very simple tests, the extent to which the fitting should approximate a conventional ejector.

The second inlet opening 23 is connected by means of a suction tube 26 to a space 27 which is near the base 16 of the cistern but on a side of an upstanding wall 28 which extends across the cistern and between two of the side walls 17, but only part way up the cistern, the top edge of the wall 28 being at or a little below normal water level within the cistern as shown in FIG. 3. The effect of this is that water flow induced from the container by the ejector action of the outlet fitting 18 quickly lowers the level in part of the container so that a rapid response occurs upon opening of a tap in the network 10. The head pressure under ordinary circumstances will be insufficient to ensure this desirable rapid response.

A side wall 17 of the container 11 supports a pair of float controlled valves, the first float controlled valve 30 being positioned with its discharge opening 31 directly above the first inlet opening 22 of the outlet fitting 18 and is connected thereto by means of a conduit 32 which contains an air break aperture 33 arranged well above water level so as to ensure against suction of water into the mains water supply 12 upon failure of pressure therein. Thus water flow discharging from the first float controlled valve passes directly through the outlet fitting 18 to induce water flow from the space 27 through the suction tube 26.

The second float controlled valve 35 is positioned alongside the first valve 30 but arranged to discharge directly into the container. As shown in FIG. 3, the float 36 of the first valve 30 is positioned above the float 37 of the second valve 35, so that the second valve does not commence to discharge until the water level lowers by an amount at least equal to the distance in height between the valve floats.

The two

valves

30 and 35 are interconnected at their inlet ends by a mains pressure conduit 39 (FIG. 2). A side wall of the cistern contains an overflow conduit 40, and the cistern has on it a removable closure cover 41. The capacity of the entire container must be sufficient to accommodate water which enters the container due to expansion in the hot water container 1 1.

Consideration of the above embodiment will indicate that the invention is exceedingly simple. However in practice it is found to greatly improve the operation of the cistern and avoid possibility of discomfort to a user. The cost of the additional valve is very much less than the additional costs incurred if the cistern 13 is installed several feet above the hot water container, for example above the roof of a house.

What we claim is:

1. A cistern comprising a container having a base and side walls, a water outlet fitting in the base (or in a side wall near the base), the outlet fitting having an internal conduit with three openings in water flow communication with one another, including an outlet opening directed outwardly from the container, a first inlet opening in alignment with the outlet opening, and a second inlet opening in communication with the space in the lower portion of the container, a first float controlled valve in the container, a conduit extending between the discharge opening of said first valve and said first inlet opening, a second float controlled valve in the container, and pipe connection means on the inlet ends of each said valve connectable with a high pressure water supply, so constructed and arranged that upon initial outward water flow from the outlet opening, the water level in the container drops and the first float controlled valve opens whereupon water flow through said outlet fitting induces water flow from the container thereby further dropping the water level whereupon said second float controlled valve opens.

2. A cistern according to claim 1 wherein the water outlet fitting is a T member.

3. A cistern according to claim 2 further comprising a wall within the container extending between the side walls of the container which divides the lower part of the container into two compartments, the floats of the float controlled valves being in the first compartment, the outlet fitting being in the second compartment, and a suction tube extending from said second inlet opening through the wall to the first compartment, the height of the wall being equal or nearly equal to the normal depth of water in the cistern when both float valves are closed, so constructed and arranged that the level of the water in the first compartment lowers but the level of the water in the second does not lower below the upper edge of the wall upon discharge of the container.

4. A cistern according to claim 1 wherein the wall of said conduit contains an air break aperture positioned above water level.

5. A hot water supply network having a hot water container, a hot water pipe leading from the hot water container, a series of outlet valves in the hot water pipe, and a cistern positioned above the container and above the'level of the highest hot water outlet, said cistern being according to claim 1.

nun-

Claims

2. A cistern according to claim 1 wherein the water outlet fitting is a ''''T'''' member.

5. A hot water supply network having a hot water container, a hot water pipe leading from the hot water container, a series of outlet valves in the hot water pipe, and a cistern positioned above the container and above the level of the highest hot water outlet, said cistern being according to claim 1.