Patent Publication Number: US-2010108156-A1

Title: Fluid flow valve

Description:
This is a National Phase Application filed under 35 U.S.C. 371 as a national stage of PCT/IL2008/000878, filed Jun. 26, 2008, an application claiming the benefit under 35 USC 119(e) U.S. Provisional Application No. 60/929,670, filed Jul. 9, 2007, the content of each of which hereby incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to fluid flow valves of the type adapted on the one hand to allow discharge of trapped gas at relatively small or large quantities, and on the other hand allow ingress of air so as to provide vacuum relief when the line is drained. 
     BACKGROUND OF THE INVENTION 
     Such air purge valves are generally fitted to liquid conduits such as, for example, water mains distribution lines or other liquid supply lines, and are designed to ensure the release of air or other gases from the conduits, thereby avoiding the production of air locks, for example, which would interfere with the flow of the liquid. 
     For this purpose, two different kinds of air purge valves are known. In both kinds, a float is located in a housing which is coupled at a lower end thereof to the conduit to be vented and which is provided at its upper end with a venting aperture. In the course of normal operation with the flow of liquid through the conduit, the housing fills with liquid and the spherical float is forced upwardly against the outlet aperture sealing the same. When, however, air accumulates in the conduit, the float is displaced downwardly under its own weight thereby opening the outlet aperture with consequent venting of the air. 
     In a first kind of air purge valve, often referred to as the ‘automatic valve’, the outlet aperture is of relatively small dimensions and the float is displaced downwardly as soon as any air appears in the housing, thereby allowing for the continuous, automatic venting of the conduit. However, in view of the relatively small dimensions of the aperture, this automatic type cannot cope with situations wherein large quantities of air have to be vented and where such a situation arises, not all the air is released and some of it passes into the line, causing a build-up of air pressure and ultimately the creation of an air lock. 
     In order to cope with the situation wherein sudden large quantities of air appear in the line and have to be released, the so-called ‘kinetic valve’ is used. This valve has a relatively large aperture through which large quantities of air can be rapidly and effectively vented. However, with such kinetic valves, once the housing thereof has filled with liquid and the float has been pressed against the large aperture so as to seal it, the valve will only reopen once the pressure in the housing has dropped to atmospheric pressure and, in consequence, the kinetic valve cannot be used for the continuous release of small amounts of air. 
     In view of these limitations on the respective use of the automatic and kinetic valves, so called ‘combined valves’ have been designed which effectively consist of a kinetic valve and, superimposed thereon, an automatic valve. With such combined valves, continuous release of relatively small amounts of air throughout operation take place through the automatic valve, whilst sudden bursts of large quantities of air are released through the kinetic valve. 
     U.S. Pat. No. 4,770,201 discloses in its abstract a fluid flow valve such as a faucet or air-purge valve comprising a housing having defined therein a fluid through-flow aperture with a valve seating formed in the housing and bounding said aperture. A flexible closure membrane is secured at one end to the housing and is adapted to be biased, under fluid pressure in the housing, against the valve seating so as to seal the aperture. Membrane displacing means are secured to an opposite end of the membrane so that displacement of the displacing means in a first sense progessively detaches successive transverse portions of the membrane from the seating so as to open the aperture while displacement of the displacing means in an opposite sense allows for the membrane to become sealingly biased against the seating. 
     U.S. Pat. No. 6,145,533 discloses in its abstract an air release valve comprising a housing having a fluid inlet and a fluid outlet, a valve plate within the housing between the inlet and outlet, the valve plate having a pair of apertures; a valve seal assembly including a seal engageable with the valve plate overlying the apertures; a float located in the housing upstream of the valve plate and connected to the seal, the float displaceable between first and second positions in the housing such that displacement of the float in one direction opens the apertures, the float having a tapered end remote from the seal, the tapered end having a truncated substantially flat bottom surface and a groove extending across the flat bottom surface. 
     U.S. Pat. No. 7,011,105 discloses in its abstract a valve with a housing connectable to the pipeline or vessel. The housing has a first outlet venting to atmosphere and a control chamber which is exposed to internal pressure in the housing via a control chamber inlet. A first valve closure can move to open and close the first outlet. This valve closure is exposed to control chamber pressure tending to move it to close the first outlet and to internal housing pressure tending to move it to open the first outlet. When the housing is pressurized the first valve closure is maintained in a closed position by virtue of an unbalanced pressure force acting on it that is attributable to exposure of the valve closure to atmosphere through the first outlet. There is also a control chamber outlet from the control chamber to atmosphere. This outlet is larger than the control chamber inlet. The valve also incorporates a float in the housing which is arranged to be buoyed up by liquid entering the housing from the pipeline and a second valve closure carried by the float which is arranged to open and close the control chamber outlet in response to movement of the float caused by variations in the level of liquid in the housing. Downward movement of the float in response to a drop in liquid level in the housing, attributable to accumulation of air in the housing, causes the second valve closure to open the control chamber outlet. This allows the control chamber to vent to atmosphere. The pressure in the control chamber drops relative to the internal housing pressure and creates an unbalanced pressure force on the valve closure which causes it to open the outlet. The housing can then vent to atmosphere via the outlet: 
     It is an object of the present invention to provide an alternate flow-control valve of the combined type, with some improved features. 
     SUMMARY OF THE INVENTION 
     The present invention offers a cheep yet reliable valve which combines a kinetic stage valve for facilitating fluid flow at substantially high rate, and an automatic stage valve for substantially low flow rate. The device according to the present invention has the advantages of a large devise yet it is more compact in size and cheep in manufacture. 
     According to the present invention there is provided a gas purge valve comprising a housing formed with a fluid inlet and a fluid outlet, said fluid outlet bounded by a kinetic valve seating, and a sealing assembly comprising a float member coaxially displaceable within the housing, and a sealing cap coupled to said float member; the sealing cap being axially displaceable with respect to the float member between a first position in which it conjoins the float, and a second position in which it departs from the float; said sealing cap formed at an outside face thereof with a kinetic seal fitted for sealing engagement of the kinetic valve seating, and an automatic valve aperture formed in the sealing cap and bounded by an automatic valve seating; and an automatic sealing member articulated to the float member for sealing engagement of the automatic valve seating. 
     The valve according to the present invention has one or more of the following featuring characters:
         Alternatively, or in combination, the seal for the sealing cap may be fitted in the valve body.   The float member and the sealing cap articulated thereto, at the first position at least, form together an aerodynamic capsule-like shape;   The gas purge valve and its components are substantially symmetrical about a longitudinal axis thereof;   The sealing cap, at its second position, forms a space extending between a top surface of the float and a bottom surface of the sealing cap. By a particular embodiment this space is sealed at the said second position;   At high flow rates within the valve there is formed a low-pressure zone resulting in attachment forces acting between the float and the sealing cap so as to retain them at their articulated position;   The automatic sealing portion of the sealing assembly is axially displaceable within the housing and the configuration is such that it is axially displaceable within the kinetic sealing portion which is axially displaceable within the housing;   The automatic sealing member is in the form of a flexible strip articulated to the float member at least at one end thereof;   According to a particular design the automatic sealing member is in the form of a strip of resilient material secured to the top portion of the float at an inverted U-like shape, wherein at the second position thereof the resilient strip is axially deformed into sealing engagement with the automatic valve seating, to thereby seal the automatic valve aperture;   By modifications of the invention, the seal is connected at one end to the float and at the other end to the sealing cap, or the two ends of the seal are coupled to the float, or only one end is coupled to the float and the other end is loose;   There is provided a support member under the inverted U-like shaped sealing strip to prevent its buckling upon deformation and also to assist in sealing at low pressure;   One of the automatic sealing member and the automatic valve aperture are offset with respect to a longitudinal axis of the housing, thus giving rise to a non-homogenous pealing pattern of the automatic sealing member;   According to some particular features of the valve, the housing is designed with one or more of the following features:
           The housing is made of a single element integrated with the kinetic valve seating;   A coupling for fitting to a fluid line is integrated at the inlet of the housing. The coupling is for example an internal/external threading, bayonet coupling, a flange for coupling with a band, etc.;   The sealing assembly may be inserted as a whole through the inlet port of the housing having an aperture corresponding with a nominal diameter of the devise, though it may be assembled within the housing too;   The hosing is devoid of any static components apart for a flow regulator inserted intermediate the inlet port of the housing and the float member, said flow regulator supporting the float member at its lowermost position;   The housing is a substantially straight body without any major undercutting, i.e. the interior diameter of the housing is uniform;   
           The simple configuration of the housing renders it feasible to be manufactured of molded plastic material;   According to some particular designs the following geometrical ratios exist:       

         D   A   /D   n ≧0.32             where D A  is the fluid outlet diameter (the ‘kinetic seating’ diameter) and D n  is the nominal diameter of the thread of a pipe coupled to the valve;           
         D   ont   ≦D   n +28 mm             where D out  is the maximal external diameter of the housing.           
     According to an embodiment of the invention, an outlet deflector is fitted over the fluid outlet of the housing. Typically said deflector is fitted with a protective screen against dirt, insects and vandalism. Said deflector may be integrated with the body. 
     According to a variation of the invention there a one-way stopper is fitted within the deflector, over the fluid outlet, to thereby restrict fluid flow in an outwards direction only, i.e. to prevent fluid ingress into the housing via said fluid outlet. Optionally the stopper is biased into sealing engagement of the fluid outlet and will displace into an open position upon fluid egress through the fluid outlet. Thus, the valve may serve for the following functions:
         Allowing air ingress and prohibiting egress;   Allowing air ingress and only partial air egress;   Allowing air egress and prohibiting air ingress.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to understand the invention and to see how it may be carried out in practice, several embodiments will now be described, by way of non-limiting examples only, with reference to the accompanying drawings, in which: 
         FIG. 1  is a perspective general view of a valve according to an embodiment the present invention; 
         FIG. 2  is a perspective, longitudinally sectioned view of the valve of the present invention; 
         FIGS. 3A and 3B  illustrate a sealing cap used in the valve according to the invention, at a top perspective view and a bottom perspective view, respectively; 
         FIG. 4  is a top perspective view of a float closure used in the valve according to the invention; 
         FIGS. 5A to 5C  are longitudinal sections illustrating the valve according to the invention at a fully opened position, a fully closed position and at an automatic open position, respectively; 
         FIG. 6A  is a perspective view of a valve according to an embodiment of the invention, fitted with a one way stopper; 
         FIG. 6   b  is a bottom perspective view of the stopper seen in  FIG. 6A ; and 
         FIGS. 7A and 7B  are representations of modifications of the valve&#39;s housing coupling arrangements. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Attention is first directed to  FIGS. 1 and 2  of the drawings illustrating a gas purge valve in accordance with the present invention and generally designated  10 . It is noted that the valve in  FIG. 1  is fitted with a threaded coupler  12 , absent in  FIG. 2 , as will be discussed hereinafter in further detail. 
     The valve  10  comprises a generally cylindrical housing  14  formed with a coupling portion  16  which in the present embodiment is internally threaded at  18 , and is formed with a fluid inlet  20  and a fluid outlet  24 , the latter formed at a bottom face thereof with a kinetic valve seating  26 . 
     Several axial ribs  28 , radially extending are provided, two of which are seen in  FIG. 2 , and serve for the purpose of restricting displacement of a sealing assembly  30  to axial displacement within the housing and preventing rotation thereof. 
     The sealing assembly  30  comprises a float member  32  composed of a cylindrical bottom portion  34  sealed by a float closure member  38 , together defining a sealed float member. The float is formed with axial recesses slidingly displaceable over the axial ribs  28 . 
     The sealing assembly further comprises a sealing cap  40  articulated to the float closure  38 , as will be explained hereinafter. The sealing cap  40  is formed with an automatic valve aperture in the form of slit  44  and a kinetic disk-like seal  48  for sealing engagement with the kinetic valve seating  26  at the fluid outlet  24  of the housing  14 . 
     The automatic valve aperture  44  is bounded, at its bottom face with an automatic valve seating  50  sealingly engageable by an automatic sealing valve member  54 , in the form of a strip-like resilient material, secured on the top portion of the float closure  38 . In the embodiment as illustrated in  FIG. 2  and as clearly illustrated in  FIG. 4 , the top closure  38  comprises two receptacle grips  56  for coupling said automatic sealing valve member  54  however retaining its flexibility. As can be seen in  FIG. 5C , when the valve is at the so-called ‘automatic open position’ the automatic sealing valve member  54  is un-deformed and assumes a substantially U-like shape. However, upon sealing engagement with the automatic valve seating  50  ( FIGS. 2 ,  5 A and  5 B) the automatic sealing valve member  54  is deformed to ensure full contact sealing of the automatic valve seating  50 . 
     In order to ensure that the automatic sealing valve member  54  does not buckle at its deformed position, a support member  58  extends from the sealing cap  40 , under the U-like shaped sealing strip, such that at the sealing position ( FIGS. 2 ,  5 A and  5 B) it biases the resilient automatic sealing valve member  54  into sealing contact with the automatic valve seating  50 . 
     It is further noted, that in  FIG. 4 , that the float closure  38  is formed with two lateral projections  61  (one of which is seen) radially projecting therefrom, for snap engagement within recessed aperture  62  formed in the sealing cap  40 , thereby providing for some axial freedom of the sealing cap  40  with respect to the assembled float unit  32  however, ensuring that downward displacement of the float unit  32  entails retraction of the sealing cap  40  to thereby open the kinetic valve sealing as will be discussed in detail hereinafter. 
     The sealing cap  40  is axially displaceable with respect to the float member assembly  30  between a first position in which it conjoins the float assembly  32  and together assume an aerodynamic capsule-like shape ( FIGS. 2 ,  5 A and  5 B) and a second position, in which the sealing cap  40  departs from the float closure  38 , though remains articulated thereto as explained hereinafter in connection with lateral projection  62  and slidingly articulated within recesses  62 . 
     As can further be noted, for example in  FIG. 2 , the assembled float and sealing assembly are supported within the housing by a flow regulator  68  which in turn is retained within the inlet  20  of the housing  14  by an annular shoulder  70  snappingly received within a corresponding shoulder  72  formed in the inlet of the housing. The flow regulator  68  serves also to support the float and to adjust air flow between the float bottom and the regulator, so as to give rise to a low pressure zone assist in maintaining the float at the open stage during kinetic air venting. 
     As can further be seen in the drawings, the valve  10  is fitted with an outlet deflector  80 , snappingly mounted over the fluid outlet  24  of the housing. The deflector  80  is fitted with an outlet spout-like portion  82  to which a pipe extension may be fitted (not shown). A protective screen  84  is integrally fitted within the outlet reflector  80 , against dirt, insects, and vandalism. 
     The structure of the valve  10  in accordance with the present invention as illustrated in the drawings, has several unique features. For example, the housing  14  is made of a single element integrated with a kinetic valve seating  26  and the design is such that the housing is a substantially straight body without any undercutting i.e. the interior diameter of the housing is substantially uniform, allowing for its simple manufacture e.g. by molding plastic material. 
     According to the design of the valve  10 , the sealing assembly  30  is inserted into the housing  14  as a whole, through the inlet port  20  of the housing  14  having an aperture corresponding with a nominal diameter of the housing D. 
     According to some particular designs, the following geometrical ratios exist in the housing. 
         D   A   /D   n ≧0.32             where D A  is the fluid outlet diameter (the ‘kinetic seating’ diameter) and D n  is the nominal diameter of the thread of a pipe coupled to the valve;           
         D   out   ≦D   n +28 mm             where D ont  is the maximal external diameter of the housing.           
     As further noted in the drawings, the gas purge valve  10  and its components are substantially symmetrical about a longitudinal axis of the valve being the result of the simple structure of the device. 
       FIGS. 5A to 5C  illustrate different operative positions of the valve. In  FIG. 5A  the valve  10  is in the so-called ‘fully opened position’, wherein the valve assembly  30  rests on the flow regulator  68  and wherein the sealing assembly  30  is at its so-called first position namely wherein the sealing cap  40  rests over the float closure  38 , such that the kinetic valve fluid outlet  24  is entirely open, allowing for the discharge of substantially large amounts of gas therethrough. Gas flow is facilitated through a gap existing between the float assembly  32  and the inner walls of the housing  14 . The capsule-like design of the float and sealing assembly are such that at high flow rates within the valve, there is formed a low pressure zone designated at  88  and resulting in attachment forces acting between the float assembly (namely the float closure  38 ) and the sealing cap  40  so as to retain them at their articulated, adjoining position. 
       FIG. 5B  illustrates a position in which liquid flows into the housing  14  through the fluid inlet  20 , resulting in buoyancy forces acting on the float assembly  32 , urging the float and the articulated sealing assembly into tight sealing engagement of the kinetic fluid outlet  24  by means of kinetic seal  48  sealingly engaged with kinetic valve seating  26  and by sealing engagement of the automatic sealing valve member  54  with the automatic valve seating  50  of the automatic valve aperture  44 . 
     The space extending between the sealing cap  40  and the float closure  38  is substantially closed and by an embodiment of the invention this space may be tightly sealed, e.g. by the provision of a sealing ring on either or both of the mating portions of the sealing cap and the float closure, respectively. 
     In  FIG. 5C  the valve  10  is illustrated in a position in which liquid level within the housing  14  decreases, allowing for descending of the float assembly  30  to thereby progressively detach the automatic sealing valve member  54  from the automatic valve seating  50  of the automatic valve aperture  44  whereby gas may now bleed through the automatic valve aperture  44  and facilitate in further detachment of the automatic sealing valve member into full disengagement resulting in further descending of the float assembly and entailing corresponding descending and disengagement of the sealing cap  40  so as to open the kinetic fluid outlet as in the position of  FIG. 5A . 
     It is noted that the automatic sealing portion of the sealing assembly is in fact axially displaceable within the housing and a configuration is such that it is axially displaceable within the kinetic sealing portion which is in turn axially displaceable within the housing. 
       FIG. 6A  illustrates a valve in accordance with a modification of the invention the difference being in the provision of a one-way stopper  90  formed with a stem portion  92  slidingly received within a receptacle  94  of the deflector  80  and comprises a sealing portion  96  fitted for sealing engagement with the automatic fluid outlet  24 . 
     The arrangement is such that the stopper is a one-way valve normally biased downwards under its self-weight into sealing engagement of the outlet  24 . However, owing to its light weight, it will displace upwardly (not shown) to disengage from the outlet  24  and facilitate free flow through the kinetic fluid outlet  24 . According to a modification, there may be a biasing member the force of which being controllable so as to determine the opening force required for displacing the valve into its open position. 
     Turning now to  FIG. 7A , there is illustrated an embodiment of the invention wherein the coupling portion  16 ′ of the housing portion  100  is fitted with an external threading  102  for coupling within a corresponding threaded pipe portion (not shown). In the embodiment of  FIG. 7B , the coupling portion  16 ″ comprises a laterally extending flange  106  for coupling to a corresponding flanged tube member  108  by means of a bolt and knot  112  or by means of a brace member  116 . 
     According to still an embodiment of the invention, one of the automatic sealing member and the automatic valve aperture are off-set with respect to a longitudinal axis of the housing, thus giving rise to the non-homogeneous pealing pattern of the sealing member. 
     While there has been shown a preferred embodiment of the invention, it is to be understood that many changes may be made therein without departing from the spirit of the invention.