Abstract:
A sillcock which has freeze resistance, backflow contamination resistance and back pressure release from the downstream water, having a resilient, radially compressible and expandable back pressure seal valve which is also axially movable a controlled amount to thereby cover or uncover an inner vent hole between the water passage and a vent passage, to allow pressure release from the water flow passage to the atmosphere.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to water valves, at times known as sillcocks, and at times known as water hydrants, and more particularly relates to sillcocks normally intended to be mounted at the exterior of a wall of a building, and having freeze resistant characteristics, anti-backflow contamination resistant characteristics, vacuum breaking characteristics, and downstream pressure venting. 
     A variety of sillcocks having both freeze resistant and contamination resistant characteristics have been proposed heretofore. The freeze resistant characteristic results from the shutoff valve being actuated by an exterior control handle with the valve located a significant distance inwardly from the handle to be well within the protective confines of the building. Efforts to achieve contamination resistance typically involve a check valve which opens to allow water outflow but closes against water inflow. Thus, resistance to backflow of water under back pressure as from an external water hose back into the system, for example, is provided. This is desirable to eliminate contamination of the potable water supply to satisfy requirements such as ASSE 1019 which has been widely adopted by many communities. Contamination can occur if back pressure allows reverse flow of water back through the water outlet to contaminate the internal potable water supply in a building. 
     Unfortunately, the known sillcocks or hydrants achieving freeze resistant and anti-backflow contamination features are complex in structure and costly to fabricate. Immediate backflow resistant character can be provided using a resilient, radially compressible-expandable check valve such as that set forth in U.S. Pat. Nos. 3,122,156 and 4,209,033. This latter patent also incorporates a vacuum breaking or release vent system for the space between the main shutoff valve and the water outlet, for release of a potential vacuum which could be created in that zone to cause back siphonage as from a hose. 
     SUMMARY OF THE INVENTION 
     An object of this invention is to provide a novel sillcock which has freeze resistance, backflow contamination resistance, vacuum breaking, and back pressure release from the downstream water, and which accomplishes all of these desirable characteristics with a simple, relatively inexpensive structure and combination. The novel sillcock achieves backflow resistance and vacuum breaking with a resilient, radially compressible and expandable back pressure seal valve which is also axially movable a controlled amount along the axis of either the main water valve or of the hollow tubular stem that connects the external control handle to the interior main water valve. The axial movement thereby radially covers or uncovers an inner vent hole between the water passage and a vent passage through the hollow stem, to allow pressure release through the inner vent hole, through the vent passage, to an added outer vent hole communicating with the atmosphere. Thus, when the pressure in the water flow passage communicating with the water outlet is greater than the main water pressure upstream of the back pressure seal valve, the seal valve will not only be radially expanded to close off against reverse flow, but will also shift axially inwardly to uncover the inner vent hole and thereby allow the pressure to be vented and released through the hollow stem to the outer vent hole and hence to the atmosphere. 
     The resilient seal has an annular lip around the largest diameter portion of the seal, to sealingly engage the inner periphery of the water tube. It also has a pair of axially spaced, inner periphery seal lips around the smallest diameter portion of the resilient seal member, to sealingly engage the outer periphery of the main water valve or alternatively the tubular stem, astraddle the inner vent hole in the normal sealing position, closing off the inner vent hole. Yet, when axially shifted under the pressure differential which may be encountered, the inner seal valve axially shifts to expose the inner vent hole and allow the pressure release. 
     These and other objects, advantages and features of the invention will become apparent upon studying the following specification in conjunction with the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a sectional elevational view of the first embodiment of the novel sillcock assembly taken on plane I--I of FIG. 6; 
     FIG. 2 is an end elevational view of one form of back pressure seal valve for the combination in FIG. 1; 
     FIG. 3 is a sectional view taken on plane III--III of FIG. 2; 
     FIG. 4 is an end elevational view of a second form of back pressure seal valve for the combination in FIG. 1; 
     FIG. 5 is a sectional view taken on plane V--V of FIG. 4; 
     FIG. 6 is an end elevational view of the sillcock assembly; 
     FIG. 7 is an enlarged sectional view of a portion of the assembly in FIG. 1; and 
     FIG. 8 is a sectional elevational view of the second embodiment of the novel sillcock. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings, the water sillcock assembly 10 comprises a hydrant body 12 having an inner end 12&#39; and an outer end 12&#34;, as well as a threaded water outlet spout 12a of conventional type. Connected to inner end 12&#39; of sillcock body 12 is a water tube 14 which is elongated so as to extend through a wall and inside a building structure (not shown) against which flange 12b of body 12 abuts in conventional fashion. Although water tube 14 may be an initially integral part of a one piece body, preferably it is attached to it as by soldering to the socket on the inner end of body 12 as shown. 
     At the inner end 14&#39; of tube 14 is what is known as an adapter end 16 which has its downstream end 16&#34; connected to the inner end 14&#39; of tube 14, and having its upstream end 16&#39; adapted to receive a water pipe (not shown) from a water supply source for inflow of water to adapter end 16. At the discharge end 16&#34; of adapter end 16 is a conventional main water valve 18 which may be rotated to open or close the water flow line in conventional fashion. Valve 18 has a seal disc 18a to seal against adapter end valve seat 16a. Valve 18 has outer peripheral threads 18b engaging inner peripheral threads in adapter end 16. To rotationally operate water valve 18 to open or close it, an elongated actuator stem 20 is provided. The inner end 20&#39; of stem 20 is flared and receives downstream end 18&#34; of water valve 18 to which it is affixed as by soldering. Connected to the outer end 20&#34; of actuator stem 20 is a conventional actuator handle 22. Actuator stem 20 is hollow, forming a hollow vent tube with an internal vent passage 20a. An inner vent hole 20b through the wall of the hollow cylindrical downstream end 18&#34; of water valve 18 allows fluid flow communication between the annular water flow passage 14a between tubes 14 and 20, and passage 20a. Tube 20 also includes an outer vent hole 20c through the wall of the tube, between inner vent passage 20a and the ambient atmosphere adjacent handle 22. Specifically, this outer vent hole 20c is axially between handle 22 and packing seal 24 that seals off the end of the water tube between the outer periphery of vent tube 20 and the inner periphery of body 12 downstream of water outlet 12a. This packing seal may include a conventional packing nut 24a threaded to the interior of outer end 12&#34; of body 12. 
     Referring now specifically to the inner end of hollow actuator stem and vent tube element 20, there is a back pressure seal valve 26 around the periphery of the cylindrical end 18&#34; of valve 18. This seal valve is of generally frustoconical configuration, having its larger diameter portion downstream and its smaller diameter portion upstream. This seal is of elastomeric material such as rubber or the equivalent, being flexible to be radially compressed and expanded under the action of water flow and pressure, and its inherent resilience and memory. The inner diameter and periphery are basically the same as or slightly smaller than that of the outer periphery of valve end 18&#34;. The outer diameter and periphery of seal valve 26, when expanded, abut against the inner periphery of water tube 14. When water flows from the adapter end past the flow control valve 18 toward outlet 12a, seal valve 26 is resiliently radially compressed to allow water to flow past its outer periphery. However, when water flow is terminated and especially if back pressure is applied to this seal valve, it is again expanded radially into sealing contact at its outer periphery with the interior periphery of outer tube 14 to serve as a check valve against reverse flow. 
     This seal valve also has another unique feature using the combination vent tube and vent holes. More specifically, it can move axially along the valve end 18&#34; a controlled amount between the two positions depicted in solid lines and in dashed lines in FIG. 7. Thus, under the pressure of outward water flow, not only will this seal valve be radially compressed, but it also will move axially outwardly to the solid line position in FIG. 7 where the inner periphery collar abuts against an outer axial stop which is preferably the flared inner end 20&#39; of tube 20. In this position, the inner diameter ring of the seal valve covers vent hole 20b and seals this vent hole. This sealing action preferably occurs because of a pair of peripheral sealing lips 30 and 30&#39; (FIG. 3) axially spaced from each other on the smallest diameter portion, i.e., inner periphery, of seal valve 26, so as to straddle vent hole 20b in this position. Therefore, during water outflow, no fluid passes through vent hole 20b. Two alternative configurations of the seal valve are depicted in FIGS. 2 and 3, and FIGS. 4 and 5, respectively. The second configuration seal valve 126 also preferably includes the pair of axially spaced inner periphery sealing lips 30 and 30&#39;, but the two have a somewhat different configuration on the outer sealing lip 26&#39; and 126&#39; respectively. 
     The axially inward position of seal valve 26 is limited by the outer end of threads 18b of water valve 18, which threads form the axial inner stop. In this axial inner position, vent hole 20b is uncovered and exposed to the water passage 14a downstream, i.e., outwardly, of seal valve 26, and to the vent passage 20a in the vent tube/water valve stem. Movement to this position is caused by water back pressure so as to not only radially expand seal valve 26 against rearward, i.e., inward, flow of water into the system, but to also allow back pressure release with venting of fluid from the water tube chamber 14a between the seal valve 26 and the packing seal 24. That is, sufficient fluid can flow through inner vent hole 20b, vent passage 20a, and outer vent hole 20c to the atmosphere, to relieve this area of the water tube of greater than atmospheric pressure. This is advantageous to, among other things, assure against reverse flow of potentially contaminated water back into the water system within the building. Back pressure can be caused, for example, by water in a hose (not shown) attached to the water outlet 12a in conventional fashion. 
     In operation, therefore, when handle 22 is actuated to rotate it and rotate stem 20 and thereby main water valve 18 which moves on actuator end threads 18b to open the valve, water flows outwardly in the direction indicated by the arrow, past main valve 18, thereby shifting seal valve 26 to its outer position against outer stop 20&#39; to thereby close off vent hole 20b. The water radially compresses seal valve 26 to flow past its outer periphery to outlet 12a. When the water is subsequently shut off by rotating handle 22 in the opposite direction, to rotate tubular stem 20 and water valve 18, if there is residual back pressure in the water pipe downstream from the seal valve, this will cause two different types of movement of the seal valve, one being radial expansion of the seal valve to cause its outer lip, e.g., 26&#39;, to sealingly engage the inner periphery of water tube 14, and the second being to shift it axially to uncover vent hole 20b and thereby allow back pressure release of this section of water tube so that a continued back pressure is not applied to the seal. If there is a negative pressure, i.e., vacuum, in this space between seal valve 26 and packing seal 24, the conventional vacuum breaker 40 will allow atmospheric air input, to thereby release or break the vacuum. This vacuum breaker 40 comprises a cap 42 on body 44. Body 44 is threadably attached to the top of sillcock body 12, sealed by an O-ring 56. Inside body 44 is a passageway containing a valve 48 with an annular seal gasket 50 to close against an annular shoulder in the body passageway. This valve is normally closed but can open with an inward pressure differential between atmospheric and water passage 14a to break the vacuum. 
     In the first embodiment described above, seal valve 26 is located on the hollow extended end 18&#34; of water valve 18, with hollow tubular vent stem 20 integrally extending from end 18&#34;, and with vent hole 20b being through end 18&#34;. In a second alternative embodiment depicted in FIG. 8, seal valve 26 is positioned on tube 20 which has vent hole 20b through its wall. The other components of the assembly are like and have like numerals as in the first embodiment, except that the axial inner and outer stops for the seal valve are slightly different. Specifically, the axial outer stop 28 is a protrusion on tube 20, and the axial inner stop is the end 18a of water valve 18. A conventional vacuum breaker 40 as in FIG. 1 could and normally would be positioned on the top of body 12 as in FIG. 1. 
     Conceivably the various components of this assembly may be modified somewhat to suit a particular type of installation, but without departure from the concept presented. Therefore, it is intended that the invention is not to be limited to the preferred illustrative embodiments set forth, but only by the scope of the appended claims and the reasonably equivalent structures to those defined therein.