Patent Abstract:
A ballcock valve with a valve body mounted on a tubular riser with a valve seat which passes water from the riser. The valve body includes a base and a removable cap which enclose valve workings. A screen body passed through the valve seat has a central passage and openings to the passage that exclude particulate solids. A flow control is fitted to the screen body. The combined screen body and flow control is upstream from the valve seat. Preferably a retainer releasably holds the screen body against axial movement when installed.

Full Description:
FIELD OF THE INVENTION 
     A readily serviceable screen for excluding particulate solids from rate-controlled pressure-actuated ballcock valves of the type used in toilet tanks. 
     BACKGROUND OF THE INVENTION 
     Municipal regulations regarding the use of water in the flushing of toilets generally require the use of flow-rate controls (flow controls) to limit the amount of water discharged for each flush and to discourage multiple flushes. Also, especially when the ballcock mechanism depends on a pressure differential, flow at an excessive rate can interfere with the proper functioning of the ballcock valve itself. 
     Accordingly, modern pressure-differential ballcock valves are mostly provided with a flow control whose function is to limit the rate of flow, making it constant over a substantial range of pressures. A pervasive problem with flow controls, and also with the pressure-responsive mechanism is its sensitivity to particulate solids that tend to plug up the necessarily small orifices. Many times this is solved in the control mechanism by placing rods in the critical orifices with clearances that movement of the rod tends to keep clear and which are too small for the particulates to pass. Also, it is common to place screens in the ballcock&#39;s water supply riser. The problem here is evident. After a time, the upstream side of the screen becomes clogged and the valve must be serviced to flush the line and clean the screen. 
     This sounds like a simple matter, and to a qualified person it is. A plumber finds it a pleasant, quick and financially rewarding task, and a householder who is skilled with his hands and is knowledgeable can do the job instead. However, in conventional installations the tank must be drained, the ballcock valve removed completely, the water turned back on to flush the line, taking care to divert the stream, the screen cleaned, and the valve re-installed. The task to the average person is not simple at all. 
     It is an object of this invention to provide a ballcock valve with a readily removable top mechanism which can expose a readily removable and replaceable combination of screen and flow control that can be lifted out to be cleaned and to permit the line to be flushed, and then replaced along with the top. This is an elegantly simple matter which a person with almost no skill can accomplish. 
     BRIEF DESCRIPTION OF THE INVENTION 
     This invention is carried out in a ballcock valve which has a tubular water supply riser rising into a tank. Atop the riser there is supported a pressure differential mechanism (sometimes herein called “valve workings”), whose opened or closed setting is determined by the elevation of a float in the tank. 
     The valve workings itself is housed in a body in a chamber formed of a base and a cap. Removal of the cap gives access to to the valve workings, and permits its removal. A combination flow-control and screen is held in the riser, directly upstream from the valve workings. 
     According to this invention, the screen projects into the riser to keep particulate solids in the riser, out of the chamber and out of the flow control. 
    
    
     The above and other features of this invention will be fully understood from the following detailed description and the accompanying drawings, in which: 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an axial cross-section of a ballcock valve incorporating the preferred embodiment of the invention; 
     FIG. 2 is an exploded view of a portion of the valve of FIG. 1, with its upper portion removed; 
     FIG. 3 is a side view of a combined screen and flow control; 
     FIG. 4 is a bottom view of FIG. 3; and 
     FIG. 5 is a top view of FIG.  3 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A ballcock valve  10  incorporating the invention is shown in FIG. 1. A vertical tubular water supply riser  11  is connected by means not shown to a source of water. It is conventionally fitted into a port in the bottom of a water tank. The tank holds water to be released to the toilet when a flush is needed. The details of mounting the riser are omitted as being unnecessary to an understanding of the invention. 
     The ballcock valve includes a body  24  having base  25  with a peripheral rim  26 . This rim bears a set of bayonet flanges  27 . A central opening  28  opens from the riser into a valve seat  29 , which in turn opens into a dish-like, flow channel  30 . A tank supply port  31  discharges into a tank supply tube  32 . A peripheral seal  33  extends around an upper surface. 
     The body also includes a cap  35  having bayonet flanges  36  which can engage flanges  27  when in one rotated position, and can free the cap in another. The cap has a top  37  with a central aperture  38 . It also carries a hinge base  39  and hinge pin  40  to support a lever  41 . Lever  41  and arm  42  support a float (not shown), whose elevation in a tank in which the valve is mounted determines the opening or closing of the valve and thereby the water level in the tank. 
     Base  25  and cap  35  when joined together form a chamber  43 . Valve workings  50  are mounted in the chamber. They are releasably held to the cap. As shown in FIG. 1, when the cap is tightened onto the base, the columnar top  57  of the workings fits in the central opening of the cap and is held there, for example by a tooth  52  which passes through a slot  53  when aligned. When the top is turned, the tooth holds the workings to the cap. The details of these workings will be found in applicant&#39;s co-pending U.S. patent application Ser. No. 09/487,551 filed Jan. 19, 2000, entitled Ballcock Valve For Water Tanks now U.S. Pat. No. 6,244,929 issued Jun. 12, 2001, which is incorporated by reference herein in its entirety to show these details. 
     Briefly stated, these valve workings include a flexible diaphragm  60  which can be moved against valve seat  29  to close it against flow, and moved away from it to open the valve to flow. The selection is made by changing the pressure in valve chamber  61  from atmospheric to water system pressure. This is accomplished by positioning a shaped control rod  64  in vent passage  65 . This rod is moved by lever  41 , which moves in response to water level in the tank. When vent passage  65  is open it permits system pressure to enter the valve chamber  61  and the valve will be closed, passage  66  being closed. When passage  65  is closed and passage  66  is opened, the diaphragm will move upwardly to open the valve. This is a well-known operation, whose details are unnecessary to an understanding of this invention. What is important is that when the cap is attached to the base, the workings are in place and the valve is operable. 
     The objective of this invention is to keep particulate solids out of the valve beyond the valve seat. For this purpose a screen  70  is provided, to which flow control  71  is attached. 
     Screen  70  is a body  70   a  formed as a hollow tapered structure with a peripheral wall  71  having a plurality of axially extending slots  72  of a size chosen to exclude undesired solids. A collar  73  on the screen fits snugly in wall  74  of the riser (a socket may if desired be provided). Axial slits  75  are formed in the riser wall. 
     Radial protuberances  77  are formed on the screen body. In the illustrated embodiment, these are formed as fingers which are reversely tapered so that, when they have been moved past a tapered portion  78  of wall  74  of the riser, the screen can be rotated and they abut it. This will prevent axial removal of the screen unless and until the screen is turned again to align the fingers and slits. When they are aligned, water pressure in the riser will force the screen out of the tube. Until the screen is turned it will resist removal. 
     The illustrated fingers are tapered fins to match an adjacent tapered structure. Instead a straight finger adapted to engage a flat shoulder could be used for the same purpose. 
     Flow control  71  is a conventional type. It is a characteristic of these devices that, over a relatively wide pressure range, the flow rate through the valve will be essentially constant. These flow controls, include a body  80  with ports  81  facing upstream, and circular flexible O rings  82  which adjustably cover these ports so that when the pressure varies the flow rate remains constant. 
     Importantly to this invention, the flow control is immediately downstream from the screen slots, so it is protected against being fouled by solids. As a convenience, the flow control can include a slot  83  which when engaged by a blade can provide for rotating the screen to align (or misalign) the fins relative to the slots. 
     To service this valve, one needs only to turn the cap to release and remove it, rotate the screen to align the fingers and slots, turn on the water pressure to expel the screen and flow control, and let the water run long enough to clear the tube of debris. Then turn off the water, clean the screen, and reverse the procedure. That is all. 
     The fingers shown are a single example of radial protuberances which can interfere with surrounding structure unless aligned with a release path such as an axial slit. 
     This invention is not to be limited by the embodiments shown in the drawings and described in the description, which are given by way of example and not of limitation, but only in accordance with the scope of the appended claims.

Technology Classification (CPC): 8