Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K47/00—Means in valves for absorbing fluid energy
  • F16K47/02—Means in valves for absorbing fluid energy for preventing water-hammer or noise
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K25/00—Details relating to contact between valve members and seat
  • F16K25/005—Particular materials for seats or closure elements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K47/00—Means in valves for absorbing fluid energy
  • F16K47/08—Means in valves for absorbing fluid energy for decreasing pressure or noise level and having a throttling member separate from the closure member, e.g. screens, slots, labyrinths
  • F16K47/16—Means in valves for absorbing fluid energy for decreasing pressure or noise level and having a throttling member separate from the closure member, e.g. screens, slots, labyrinths the throttling member being a cone

Definitions

• This invention relates to an improved fluid shut off valve and particularly to a valve incorporating properties of fluid shock reduction in a conduit such as a water pipe by combining physical design with material specification.
• the valve is particularly suitable for use in domestic water taps and industrial fluid circuits.
• valves are used to regulate fluid flow through a particular conduit.
• valves are used to regulate the flow of water through a water pipe.
• valves One common use of valves is with screw down pattern taps and cocks which include a tap body having a fluid flow pathway extending therethrough, a valve seat located intermediate the fluid flow pathway, a tap spindle which is moveable towards and away from the valve seat usually by rotation, with the tap spindle having a recess or bore located in the lower face, and a tap head which connects to the tap body and which houses the tap spindle.
• the tap head includes an opening in the top through which an upper portion of the tap spindle extends and about which a handle is fixed to allow the tap spindle to be rotated in the tap head and towards and away from the valve seat.
• This type of tap is commonly used in domestic dwellings and industrial facilities as water outlet taps and also as the mains water isolation cock.
• Valves which are commonly used with this type of tap otherwise known as a loose tap washer include a disc like a seal which overlies the valve seat and a stem which extends from the disc-like seal and locates within the tap spindle. In this manner, advancement of the tap spindle results in the seal being brought into the engagement with the valve seat thereby stopping fluid flow through the tap body.
• the invention resides in a valve for reducing fluid shock in a conduit, the valve having a sealing face for sealing engagement with a valve seat which extends about a bore, and a fluid shock absorbing portion which, when the valve is in the closed position, overlies the bore.
• the valve is suitable for use in household taps and cocks or the mains isolating cock connecting the household to mains water supply although it should be appreciated that the valve is equally applicable in industrial situations, e.g. check valves (non-return) or commercial situations.
• the sealing face is suitably formed on one front face of a sealing body.
• the sealing body may be substantially cylindrical in configuration to suit an annular valve seat. It should be appreciated that valve seats of different configurations (i.e. polygonal) will result in the sealing body adopting a similar configuration.
• the face and preferably the sealing body is suitably formed from an elastomeric material and a suitable elastomeric material comprises rubber or a rubber blended with an elastomeric plastomer.
• a suitable rubber/plastomer blend is SANTOPRENE (registered trade mark of the Monsanto Corporation) 8000 Series butyl based rubber and EXCEED (trade mark of the Exxon Corporation) metalocene polyolefine plastomer/elastomer.
• the EXCEED may be a polyethylene derived form which is currently used only as a packaging material and has not been used for engineering applications.
• the properties of EXCEED and other metalocene derived polyolefine plastomer/elastomers are beneficial for the purposes of fluid seal construction described in the Elastomeric Seal Material Formulation below.
• the outer portion of the sealing face may be adjacent the peripheral edge of the sealing face.
• the outer portion may be profiled or otherwise configured to facilitate sealing engagement with the valve seat.
• the profile includes one or more ribs.
• the profile comprises a pair of spaced ribs extending around the valve seat and for annular valve seats, these edges or ribs are suitably annular in configuration.
• the pair of spaced edges or ribs may define between them a recessed portion which suitably has a substantially inverted "V" configuration to define inclined edges.
• a substantially inverted U-shaped configuration may be appropriate.
• the sealing face may also include a recess spaced inwardly 4 from the edges or ribs and suitably corresponding to the inner edge of the valve seat and adapted to extend across the inner edge.
• the inner recess is suitably annular in configuration.
• the recess may be substantially rectangular in cross-section.
• the inner portion may extend substantially across the aperture defined as the valve seat.
• the outer edge of the inner portion is defined by the annular recess described above.
• the sealing body is suitably provided with a configuration on a rear face thereof which can increase the strength of the body and also may increase flexibility during deformation of the inner portion.
• the configuration is preferably dished shape.
• the configuration is preferably of a size corresponding at least to the size of the inner portion.
• the configuration suitably extends about % through the sealing body.
• the inner portion has a projection extendable into the opening defined by the valve seat.
• the projection may comprise a tapered hollow boss.
• the boss can also function as a self-aligning locating means to assist in locating the valve onto the valve seat.
• the tapered boss may include at lest one flute to assist in passing fluid along the boss.
• the flute(s) may be tapered to reduce the turbulence caused by the flow of fluid and induced vibration of the sealing body upon insertion of the projection into the opening.
• the front face of the projection may be recessed to reduce moulding shrinkage and dimensional variation of the valve during moulding.
• the stem member suitably extends at right angles from a rear portion of the sealing body and is insertable into a tap spindle.
• the stem member comprises a cylindrical rod.
• the stem member can exhibit limited pivotal motion relative to the sealing face.
• One manner of accomplishing this is to form the stem member and the sealing body monolithically from resilient material or to provide the stem member with a resilient base portion.
• the valve sealing body and stem member are integrally formed from an elastomeric material and is suitably moulded by any convenient method, such as by injection moulding. 5
• the valve may include a biasing means to bias the sealing face into engagement with the valve seat.
• the biasing means may comprise a spring.
• the spring may be tapered and suitably includes a helical spring.
• One end of the biasing means may be accommodated by an end member.
• the end member suitably includes an aperture to accommodate the stem member thereby allowing the end member to slide along the stem member.
• the end member comprises a substantially flat body having a configuration similar to that of the sealing body.
• the sealing body is substantially cylindrical, the end member is preferably of a round disc-like configuration.
• the end member may include a lower recess to accommodate one end of the biasing means and together with the recess in the rear face of the sealing body form a flexing cavity enabling the centre portion of the sealing body to move if impacted by a fluid shock wave.
• the lower recess suitably has a dished configuration.
• the lower recess together with the biasing means may assist in reducing fluid shock in the conduit upon operation of the valve by allowing the inner portion to deform at least partially into the lower recess.
• the lower face of the end member may be inclined inwardly from a peripheral edge to the lower recess.
• the stem member may include a longitudinal recess or groove to allow the water to drain from or air to bleed from the recess in the tap spindle upon insertion in the stem member. Thereby facilitating the correct functioning of the biasing member.
• Figure 1 is an exploded view of a valve according to an embodiment of the invention.
• Figure 2 is a section view of the valve of Figure 1 located between a tap spindle and a valve seat and in the open position.
• Figure 3 is a section view of the valve of Figure 2 in the closed 6 position.
• Figure 4 is a section view of the valve in Figure 3 absorbing a fluid shock.
• Figure 5 is a section view of an end member according to a preferred embodiment of the invention.
• Figure 6 is a view of a valve stem and sealing body according to a further embodiment of the invention.
• Figure 7 is a view of the valve of Figure 6 in association with an end member and a spring and in the closed position.
• Figure 8 is a view of the valve of Figure 7.
• Figure 9 is a composite view of a completed valve incorporating all of the abovementioned features.
• Figure 1 discloses a valve for reducing fluid shock in a conduit.
• the valve 10 comprises a stem member 11 and a sealing body 12 defining a sealing face 13.
• the valve further includes a biasing means 14 and an end member 15.
• Sealing body 12 and stem member 11 in the embodiment are integrally (monolithically) formed from an elastomeric material. It should be appreciated however that the valve could also be formed from a two-part assembly.
• Sealing body 12 is cylindrical in configuration and includes an upper face 16 and a lower sealing face 13. Stem member 11 extends at right angles from face 16. Lower sealing face 13 includes an outer portion 17 (which seals against the valve seat) and an inner portion 18 (which absorbs fluid shock). Outer portion 17 extends from an outer peripheral edge of sealing face 13, and to an inner edge which in use is adjacent the valve seat bore. Ribs 19, 20 are provided and define a recess 19A therebetween which has a substantially inverted V-shaped configuration.
• Sealing face 13 further includes annular inner recess 22 which is positioned to extend about the inner edge 23 of valve seat 24 (see Figure 7
• Ribs 19 and 20 function to facilitate sealing engagement of sealing face 13 with valve seat 24.
• the edges or ribs will provide a good line contact with valve seat 24 and any slight wear and tear can be accommodated by the resilient nature of the edges or ribs.
• the ribs also provide a localised region of enhanced elasticity, by virtue of decreased cross-section, of sufficient magnitude to accommodate the pressures required to seal the fluid flow without exceeding the physical limits of the material.
• the ribs by their design provide additional mechanical advantage by "point loading" over a restricted zone and cross-sectional mass buttressed by the relatively more massive cross-section of the sealing body disc of which they are a part.
• effective function is achieved within the physical limits of the material and the design of the valve.
• the elasticity and hardness of the material are able to be balanced by mechanical design and material properties not previously possible with earlier designs and materials.
• the recess 22 will be pressurised when in contact with water pressure which will assist in deforming ribs 19, 20 into tighter engagement with the valve seat in direct proportion to the pressure.
• This mechanism provides improved sealing and reduces the need to apply unnecessarily, excess manual torque to the sealing mechanism.
• Annular recess 22 will also assist in reducing contact between sealing face 13 and the often sharp or roughened edge 23 of valve seat 24.
• Biasing means 14 in the embodiment comprises a tapered helical spring the upper end of which locates within end member 15 and which by virtue of its dimensions is able to collapse into a space defined by its diameter and wire gauge thickness, thus requiring minimal space.
• End member 15 includes an aperture 27 to allow the member to 8 freely slide up and down stem member 11.
• Figure 2 shows how end member 15 abuts against the lower face of tap spindle or tap screw 28. In this fashion, the biasing member 14 causes sealing face 13 to be biased into engagement with valve seat 24.
• Figure 3 shows the valve 10 in the closed position whereby fluid can no longer flow through the opening defined by valve seat 24.
• Figure 3 also shows how annular recess 22 prevents contact of sealing face 13 with the sharp or roughened edge 23 of the valve seat 24.
• Figure 4 shows how the valve assists in reducing fluid shock in a conduit by coordinated mechanical movements and elastic deformation.
• a shock wave S (indicated by the arrows in Figure 4) passing through valve seat 24, the inner portion 18 of sealing face 13 is resiliently deformed upwardly and results in absorption of the fluid shock.
• the shock absorbing mechanism takes the form of a fixed diaphragm formed by the sealing body 12 being clamped to the valve seat 24 only over the valve seat surface, thus leaving the concave rear surface of the centre portion over the port opening defined by the valve seat 24 free to reciprocate against the biasing means 14 in response to fluid shock waves as they arise.
• Outer portion 17 is still in sealing engagement with valve seat 24 upon deflection of inner portion 18 thereby allowing the valve 10 to absorb fluid shock while preventing opening of the valve.
• This effect is enhanced when more than one such valve is incorporated in the same fluid circuit creating a coordinated system whereby the fluid shock load is distributed over multiple valves.
• the biasing means 14 can move from its position shown in Figure 3 to its position shown in Figure 4 to permit the resilient deflection of inner portion 18.
• Tapered portion 30 also assists in the deflection by distributing some of the clamping force radially inwards thus reducing radial "creep” or cold flow distortion of the sealing body by opposing the opposite forces generated by the clamping pressure, pressure waves and the normal reaction from the fluid in the conduit.
• Biasing means 14 takes the form of a helical tapered spring which is so dimensioned as to be able to collapse within the depth of its own wire gauge, and in so doing, requires a minimum of space to accommodate it.
• valve according to the embodiment of the invention is effective in facilitating the reduction of fluid shock while still maintaining a steady fluid seal by having an inner deformable portion and an outer clamped portion which maintains its seal upon deformation of the inner portion.
• Biasing means 14 provides further advantages in the prevention of violent oscillation between fully open and fully closed positions which commonly occurs in non-biased valves and which is a contributing factor to severe and damaging fluid shock, by making the valve a spring relief valve 10 facilitating controlled opening and closing of the valve.
• a further advantageous and preferred feature of the invention in an embodiment is to have stem member 11 resiliently formed relative to the sealing body to allow the stem member and body to hinge. This allows the sealing face 13 to engage with valve seat 24 in a fully mating manner notwithstanding that many tap spindles 28 are poorly machined and extend at an angle relative to the valve seat 24. If stem member 11 was rigid in construction, and the tap spindle 28 was slightly angled or bent, this would result in sealing face 13 contacting valve seat 24 at an angle and rotating in a planetary motion resulting in a poor seal and accelerated destructive wear and tear on the sealing body generally and on the sealing face 13 occurring.
• Biasing means 14 also functions to minimise or prevent reflux or back suction occurring in the tap. The phenomenon is relatively common and results in fluid being sucked back into the fluid circuit thereby providing a potential source of contamination. If the tap outlet were fitted with a non- spring biased valve and connected via a garden hose to a fertiliser dispenser or insecticide sprayer, the back suction may result in potentially poisonous material being drawn into the mains supply thereby endangering all users of outlets on the main. Biasing means 14 therefore adds a safety check valve function to the valve, if there should be insufficient fluid pressure present then the valve will close automatically by the action of the spring even when the tap spindle is fully open.
• Stem member 11 may include a longitudinal groove or recess.
• the groove is desirable if the stem is a close tolerance fit in the spindle bore 28a to prevent hydraulic resistance to the reciprocating action of the stem within the bore, which would interfere with the free movement of the valve.
• the longitudinal groove provides an avenue of escape for the fluid which may otherwise become trapped behind the stem within the bore. It is desirable that the stem be a close tolerance fit within the bore to help limit variation in the seating location of the valve which is a major factor in premature valve failure.
• Stem 11 acts in cooperation with the hollow conical boss centre 11 portion of the sealing body 18 to maintain consistent axial alignment of the sealing body 12 with the valve seat 24.
• a locating device in the form of a frusto-conical boss 18 is provided to prevent excessive elastic lateral displacement of the sealing body 12 by turbulence caused by the fluid flow under pressure.
• the conical boss of the sealing body centre is so designed that even when the valve is fully open the conical portion is never fully withdrawn from the fluid port defined by valve seat 24. By this means, the sealing body is always held in axial alignment with valve seat 24.
• boss 18 of the sealing body 12 possesses at least two longitudinal tapered flutes along the sides.
• the flutes impose a degree of laminar flow on the fluid which aids in reducing undue turbulence induced by high fluid pressures thereby assisting in the consistent good sealing of the sealing ' body 12.
• a further benefit appears to derive from the tapered flutes in that particulate matter in the fluid stream is less likely to lodge between the sealing surfaces and reduce sealing capacity by interfering with the sealing of the valve.
• Boss 18 also can provide a degree of variable control of the fluid flow as the valve is opened or closed. This provides a variable degree of water flow control not possible with a flat discoid form of seal. Boss 18 is hollow and open ended and can provide additional buttressing of the seal body against very high pressures which are encountered in some fluid systems. The hollow centre of the boss helps to reduce the excessive shrinkage which occurs in thick section moulded parts during the cooling stages of moulding thereby assisting in the maintenance of dimensional stability.
• valve 40 has a valve stem 41 and a sealing body 42, the stem and body being 12 monolithically and integrally formed.
• the front face 43 of sealing body 42 is provided with a sealing face as described with reference to Figures 1 to 4, and a concave rear recess 45 extending about the base of stem 41.
• Recess 45 is annular in configuration and has a diameter larger than the diameter of resiliently deformable inner portion 46.
• Figure 7 shows an assembled valve assembly comprising the valve of Figure 6 with an end member 47.
• End member 47 is formed with an aperture to allow it to slide up and down stem 41.
• the front face 48 of end member 47 is provided with a concave recess 49.
• Recess 49 is substantially planar in configuration and extends about the aperture through which stem 41 passes.
• a helical conical spring 50 is positioned about stem 41 and is sandwiched between recess 49 and recess 45.
• Figure 8 shows how this valve arrangement absorbs fluid shock. As disclosed in Figure 8, upon a fluid shock wave arriving in opening 51 (in the boss 18), inner portion 46 deforms inwardly in the process the rear face 44 of valve 40 deforms upwardly to compress spring 50 within its recess. It can be seen that this arrangement is analogous to the arrangement described in Figures 2 to 4 with the exception that the concave recess is present on both the valve 40 and the end member 47.
• Figure 9 discloses the current composite modification and subject of the invention.
• the valve as described in Figure 9 comprises a stem 60, and a sealing body 61 having a rear face 62 and a front face 63.
• Front face 63 includes the improved sealing means as also described with reference to the previous figures.
• Front face 63 has an inner deformable portion 64 which can flex inwardly with reference to the seal body, or outwardly with reference to the fluid conduit, due to the combined cavity formed by the dished recess 65 on the sealing body and the concave recess 25 on the underside of member 12 Figure 5.
• inner portion 64 includes a locating means in the form of a tapered hollow boss 66 which extends from the inner portion 64 and is configured to pass into the opening defined by the valve seat.
• Tapered boss 66 is formed with two or three opposed equidistant flutes 67 (only one shown in Figure 9). Each of these 13 flutes is tapered in configuration and converges toward the inner portion 64.
• the flute dimensions may be varied in dimension from relatively shallow to deep and wide to alter the tapered boss 66 to a star shaped configuration for the purposes of reducing vibration from turbulence and valve positioning in high pressure applications.
• the flutes assist with the uniform passage of fluid along the tapered boss 66 as the valve moves in and out of the fluid orifice described by valve seat 24 and assists in the prevention of particulate entrapment under the sealing face 63.
• the end face 68 of tapered boss 66 may include a recess or hollow. The recess or hollow functions to assist in moulding the valve by controlling shrinkage during the cooling phase of injection moulding.
• the valve shown in Figure 9 also reduces fluid shock by inward deformation of inner portion 64.
• the valve is formed from specified materials which complement the ability of the valve to absorb water hammer.
• the physical demands placed upon a screw down pattern valve seal are severe; not only must the valve be able to cope with a wide range of physical misalignments which are very common in valve housings such as water cocks, it must also be able to tolerate the habitual over tightening which is also commonly applied by operators as a consequence of experience with badly designed valves and taps and the high mechanical advantage provided by the tap screw thread. If the valve does not shut off because of an alignment fault or other tap fault the operator usually and inappropriately responds by over tightening the valve in an attempt to force the valve to close.
• the valves must also be able to tolerate a wide range of operating pressures ranging from 20psi to well over 1000psi as is common in domestic and industrial water supplies.
• the elastomeric material described previously for the composition of the sealing body provides satisfactory material properties which can overcome the above problems.
• Thermoplastic Elastomeric materials capable of being injection moulded and performing these functions 14 has in the past been limited by levels of water absorption which seriously alters the physical properties of the material thereby often leading to an unacceptable degree of unreliability. In a water valve this is a serious problem which various manufacturers have tried to solve by a large variety of mechanical and material designs but with varying and limited degrees of success.
• the elastomeric materials described above are effective in providing the valve with its mechanical potential.
• a weakness of elastomers used in known valves has been the problem that the degree of elasticity required to seal a valve is quite small and this needs to be matched with a sufficient degree of hardness such that the valve could resist the effects of over tightening.
• the material is required to provide a degree of physical sensation to the operator of a screw down pattern valve such that a suitable end point has been reached and that this must coincide with the actual fluid flow shut off. By this means the operator not only observes that the valve has shut off but also obtains the coincidental physical sensation of resistance to further tightening which a successful closure provides.
• the difficulty with most elastomers is that at the shut off point they still retain a large degree of elasticity and low levels of hardness i.e.
• injection moulding is the preferred method of manufacture because it is much more efficient in terms of labour, energy and wastage.
• Other methods of manufacture required material to calendered into a sheet of appropriate thickness from which the washers are stamped out.
• the materials available were usually not thermoplastic but thermosetting therefore with high compression set and cold flow indices. When seals are punched out of the sheet as much as 50% of the material can be wasted (cannot be reused).
• Injection moulding materials thermoplastic
• Injection moulding materials provide the capacity to deliver just the right quantity of material to a die with usually less than 25% loss in the sprues and gates but that 25% is recoverable and can be returned to the moulding process resulting in considerable economy of energy, labour and material.
• Injection moulding also permits the formation of complex shapes which are required to bring together the physical properties of the material with functional properties of the over all valve design.
• an effective composition which can be used in the manufacture of valves, and especially valves which can absorb fluid shock.
• polyolefins such as polypropylene and polyethylene as these are cheap, can be injection moulded, are water resistant and have other advantageous characteristics.
• polyolefins do not have significant or useful elastic properties and therefore are quite unsuitable for valve seals, even though they have great chemical stability.
• compounds have now been found which hitherto have not been used in the manufacture of valve seals but which have suitable properties.
• These compositions are polyolefins which are given elastic properties by production of the polyolefins using a metalocene catalyst. 16
• the metalocene manufactured plastomers acquire quite remarkable degrees of elasticity while retaining much of their original hardness and plastomeric properties, as well as their high water and chemical resistance properties. These materials offer large cost savings in manufacture which allow more complex designs to be considered which in the past could not be used for reasons of cost or because such properties were simply not available. These new polymers blur the classification and division between plastomers and elastomers allowing plastomeric and elastomeric properties to be mixed in ways not hitherto possible.

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Citations (7)

• 1998
  • 1998-03-23 AU AUPP2485A patent/AUPP248598A0/en not_active Abandoned
• 1999
  • 1999-03-23 KR KR1020007010394A patent/KR20010042051A/ko not_active Application Discontinuation
  • 1999-03-23 WO PCT/AU1999/000199 patent/WO1999049252A1/en not_active Application Discontinuation
  • 1999-03-23 CN CN99804231A patent/CN1293741A/zh active Pending

Patent Citations (7)

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