Abstract:
This pressure regulator is specifically designed to operate with a portable compressed gas cartridge thus reducing the high vapor pressure found in compressed gas cartridges down to a substantially consistent outlet pressure. Due to the nature of the crowded regulator art, the soon to be embodied pressure regulator has been specifically embodied for use in the portable compressed gas cartridge harnessing art and this specific use is carried into the claims. Exemplified in the pressure regulator embodiments is a reduced amount of components over existing designs. Additionally, safety and reliability features have been integrated into the design and will shortly be taught in the following paragraphs. A burp-off feature in all embodiments will be exemplified that vents back-pressure spikes as well as a method of adjusting the burp-off back-pressure spikes independent of regulated pressure in some embodiments.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     Provisional patent application No. 60/579,763 filed Jun. 16, 2004. 
     FEDERALLY SPONSORED RESEARCH 
     Not applicable. 
     REFERENCE TO A MICROFICHE APPENDIX 
     Not applicable. 
     FIELD OF THE INVENTION 
     This invention relates to a piston-type fluid pressure regulator featuring a novel fluid inlet valve, capable of regulating inlet pressures ranging from low to high. More particularly, the present invention is capable of regulating portable, compressed gas cartridges at high pressure down to a workable, substantially constant outlet pressure. Fewer components over the prior-art are one design emphasis thus making a simplistic and reliable regulator that is both easy and relatively inexpensive to manufacture. 
     BACKGROUND OF THE INVENTION 
     Pressure regulators have existed for many years and the field is crowded with different designs. Yet, innovative features are still being introduced into pressure regulators such as safety features, compatibility with different fluids, construction materials and others. 
     Two major species of mechanical fluid pressure regulators are common: piston-type and diaphragm-type. In general, however, these have not proven entirely satisfactory in practice. 
     A piston-type regulator uses a spring-biased piston in a bore to regulate output pressure with the piston always trying to reside in equilibrium. When not in equilibrium, the piston moves up or down in the bore thus opening or shutting an intake valve from a high-pressure source. One side of the piston is biased by a spring force and the other side of the piston is biased by pressurized gas. 
     A diaphragm-type regulator works in a very similar way. Rather than moving a piston in a bore, a diaphragm acts as a flexure, biased on one side typically by a spring. The other side of the diaphragm contains the regulated pressure. When the biasing forces on each side are not in equilibrium, the diaphragm flexes thus opening or closing an inlet valve from the high-pressure source. 
     Regulators that are designed to handle high source pressures, whether they be of the piston-type or diaphragm-type typically use a hard valve and seat as the major components of the inlet valve assembly. The design of a hard valve and seat works well until the smallest bit of contamination, corrosion, or surface imperfection or seal ‘set’ is introduced into the valve assembly. The result is a faulty regulator that will not predictably produce a substantially constant outlet pressure. 
     Likewise, a piston-type or diaphragm-type regulator designed to regulate lower source pressures typically uses a soft elastomeric seal in the valve assembly to hold back the source pressure. This art is less prone to failure due to contamination, corrosion, or surface imperfections compared to the hard valve and seat because the elastomeric seal conforms to minor valve imperfections. Unfortunately, an elastomeric seal is not capable of retaining high source pressures because the high pressures may cause permanent deformation and/or swelling. In addition, explosive decompression results when the high-pressure source is suddenly removed from an elastomeric seal sometimes causing a permanently defective seal. 
     U.S. Pat. No. 6,843,388, titled  Compressed Gas Cartridge Dispensing System Allowing Interchangeable Use Of Different Capacity Compressed Gas Cartridges And Novel Storage Feature , filed Jul. 22, 2002 by Hollars (same inventor) extensively elaborates on methods of harnessing threaded and non-threaded compressed gas cartridges. The same referenced application also discusses many of the available capacities and dimensions of compressed gas cartridges commonly available. 
     The most similar prior-art pressure regulation device located in a prior-art search that even remotely resembles the present invention utilizes an equal or greater number of components. U.S. Pat. No. 5,628,350 by Gibb titled Inflating device that comprises, at minimum, thirteen components to achieve similar results. Yet, Gibb&#39;s patent offers no pressure relief features that prevent the regulated fluid pressure from becoming excessive as will be elaborated in the following embodiments. 
     SUMMARY OF THE INVENTION 
     This pressure regulator is specifically designed to operate with a portable compressed gas cartridge thus reducing the high vapor pressure found in compressed gas cartridges down to a substantially consistent outlet pressure. Due to the nature of the crowded regulator art, the soon to be embodied pressure regulator has been specifically embodied for use in the portable compressed gas cartridge harnessing art and this specific use is carried into the claims. Exemplified in the pressure regulator embodiments is a reduced amount of components over existing designs. Additionally, safety and reliability features have been integrated into the design and will shortly be taught in the following paragraphs. A burp-off feature in all embodiments will be exemplified that vents back-pressure spikes as well as a method of adjusting the burp-off back-pressure spikes independent of regulated pressure in some embodiments. 
     The present invention has solved the problems cited above. Broadly, this is a regulator design comprising rather typical regulator architecture but with a unique hybrid valve design that has the advantages of both hard seat and soft elastomeric seal. This valve is designed to be sealed by an elastomeric seal while being supported on a rigid seat. 
     The benefits in this design allow source pressures to be rather low or extremely high. Typically, the flow-obstructing component of this assembly is a rigid ball or substantially circular disk. The rigid seat allows only the obstructing component of the valve to compress the elastomeric seal a pre-determined amount. Any additional forces on the valve obstructing part, such as from a high source pressure, transfer to the rigid valve seat, thus not further compressing the elastomeric seal and damaging it. 
     This hybrid valve assembly allows increased versatility over previous designs and has proven to work well in a pressure regulator. One major benefit is that the source pressure can start out high such as occurs when harnessing a compressed gas cartridge, or when a harnessed compressed gas cartridge is subjected to heat where only the traditional hard valve and seat design would reliably retain such source pressures. At a later time, such as when some of the fluid in a compressed gas cartridge has been consumed, the source pressure is lower. A traditional elastomeric sealed inlet valve would appropriately retain the lower pressure but would not have worked when the source pressure was higher. Therefore, a need exists for a valve that can handle extremely high inlet pressures and reliably work as the inlet pressure considerably decreases. In practice, this scenario is typical when harnessing a compressed gas cartridge and desiring a substantially constant outlet pressure regardless of cartridge (source) pressure. 
     Additionally, because the rigid valve seat is supporting the flow-obstructing component of the valve, the elastomeric seal is prevented from taking a compression-set and works well as valve assembly temperature varies. This is also resistant to contamination or corrosion allowing long-term reliable containment of high or low pressures providing advantages of both valve prior-art designs without the disadvantages of either. 
     The main regulator body is preferably molded from a fiber-reinforced plastic therefore features can easily be reproduced on each unit once the initial molds are built. 
     A safety feature that particularly is preferred is negative vents that allow fluid to escape the regulator should the pressure contained by the piston and biased by the regulator main spring become excessive. It is an object of the invention to provide adequate system adjustability so that the regulator can burp off excessive back-pressure. 
     This regulator is intended to be manufactured from as few components as possible. 
     The regulator is intended to be manufactured utilizing as many parts as possible out of a plastic material. 
     The intention of this design is simplicity through fewer parts with perhaps lower manufacturing cost than any existing regulator available today. Additionally, high reliability should be realized from the repeatability standpoint of plastic molded parts. Once the design is proven, each duplicate part should be substantially equal. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The figures are exemplary of different embodiments of the present invention. Each illustration conveys the invention and is not to be considered as limiting, rather, exemplary to the scope and spirit of the present invention. Like components in the figures share identical numbering. 
         FIG. 1  illustrates a partial cross-sectional view of an exemplary piston-type pressure regulator of the present invention comprising a compressed gas cartridge and cartridge-retaining cup threadably attached, in accordance with an embodiment of the present invention; 
         FIG. 2  illustrates a cross-section of an exemplary piston-type pressure regulator assembly of the present invention similar to that shown in  FIG. 1 , comprising a non-threaded lance housing, less a cartridge and cartridge-retaining container; 
         FIG. 3  illustrates an exemplary sectioned close-up view of a piston seal situated in its approximate operating position with respect to the regulator bore, in accordance with an embodiment of the present invention. Note: piston not illustrated in this view; 
         FIG. 4  illustrates a cross-section view of an exemplary piston-type pressure regulator assembly comprising an adjustable height plunger and non-threaded lance housing, in accordance with an embodiment of the present invention; 
         FIG. 5  illustrates a cross-section view of an exemplary piston-type pressure regulator assembly comprising an adjustable height plunger and a threaded lance housing, in accordance with an embodiment of the present invention; 
         FIG. 6  illustrates an assembled cross-section view of a piston-type pressure regulator assembly comprising a threaded lance housing, in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an exemplary embodiment of a pressure regulator  20  of the present invention. Although the present invention is primarily intended to be used with a pressurized cartridge  21  consisting essentially of CO 2  gas, other pressurized gases or fluids may be harnessed out of compressed gas cartridges such as nitrogen or oxygen. Pressure regulator  20  generally includes a cartridge-retaining container  38  and a regulator body  44 . Cartridge-retaining container  38  and regulator body  44  are preferably molded from a glass-filled nylon or similar material. A female thread  59  on cartridge-retaining container mates with a male thread  63  that is integrally formed as a feature on regulator body  44 . Naturally, other materials exhibiting the afore-mentioned characteristics are equally suitable. Compressed gas cartridge  21  comprises a neck  26  that fits into a non-threaded lance housing  24  that is an integral feature of pressure regulator  20 . 
       FIG. 2  illustrates a cross-section view of an exemplary assembled pressure regulator  20 , in accordance with an embodiment of the present invention. A lance  30  is press-fit into the upstream end of a valve chamber  45  and punctures compressed gas cartridge seal, distally located on neck  26 , shown in  FIG. 1  when the same is brought into contact with lance  30 . Current art utilizes both hollow and solid piercing lance designs. Hollow piercing lance  30  is illustrated showing a fluid port  32  disposed directly through the middle of piercing lance  30 . 
     Formed within the interior wall of a lance housing  24  is an annular groove  31  that receives a piercing lance sealing ring  28 . Upon harnessing compressed gas cartridge  21 , shown in  FIG. 1 , sealing ring  28  creates an airtight seal between lance fluid port  32  and distal face of cartridge neck  26 , shown in  FIG. 1 . Lance housing  24  currently has two major variations in the art being non-threaded and threaded. This embodiment illustrates non-threaded lance housing  24  and requires the use of cartridge-retaining container  38  to harness compressed gas cartridge  21 , both shown in  FIG. 1 . 
     Further downstream from piercing lance  30  is valve chamber  45 . At the upper end of valve chamber  45  is a valve assembly  22  that controls the flow of gas passing through pressure regulator  20 . Main valve assembly  22  includes a rigid valve ball  46 , a spring  50 , and a valve ball sealing ring  48 . Rigid valve ball  46  is preferably made of a hard, metallic material such as stainless steel or hard-chrome plated steel. Other materials, even non-metallic, possessing adequate material properties are also considered to be within the scope and spirit of this invention. Main valve assembly  22  is incorporated into body  44  in the following manner. Valve ball sealing ring  48  is inserted into valve chamber  45  and positioned within a groove  41  provided at the downstream end of valve chamber  45 . Following insertion of sealing ring  48 , valve ball  46  is positioned in contact with sealing ring  48 . The leading end coil of compression spring  50  is then positioned about the circumference of valve ball  46  and is compressed within valve chamber  45  by press-fitting piercing lance  30  into the upstream end of valve chamber  45 . 
     Illustrated in  FIG. 2  and additionally in  FIGS. 4-6 , a valve ball seat  49  extends into valve chamber  45  to limit the motion of valve ball  46  during inoperative periods and high-pressure situations such that sealing ring  48  is prevented from over-deformation and permanent deformation by rigid ball seat  49  that supports valve ball  46  when main valve assembly  22  is closed, thereby enabling long-term containment of unused gas. Additionally, this design of supportive valve ball seat enables extremely high pressures and pressure shocks to be reliably contained within valve chamber  45  as is the case upon lancing a compressed gas cartridge where initial cartridge lancing can slam main valve assembly  22  with high pressure gas. Additional benefits of rigid valve ball seat  49  limiting travel of valve ball  46  allows this valve assembly to handle cold and hot temperatures as well as temperature swings during service thereby affecting seal hardness as is common when harnessing high-pressure compressed gas cartridges, particularly at high flow rates where the gas is cool as it is changing from a substantially liquid phase in the cartridge to a gaseous phase as it is leaving the cartridge. The controlled limited compression of sealing ring  48  prevents sealing ring from taking a permanent compression set yet allows for a reliable seal. 
     Immediately downstream from valve ball seat  49  is a plunger channel  53 . Plunger channel  53  is dimensioned to receive a plunger  52  that communicates at a contact interface  47  with valve ball  46  to open valve assembly  22 . The dimensions of plunger  52  are slightly smaller than plunger channel  53 . Two reasons for these dimensions are to allow plunger  52  to freely move in plunger channel  53  as well as allowing means for a fluid connection between valve chamber  45  and downstream to a regulated pressure contained on the bottom side of a piston  54  as will be discussed next. 
     Plunger  52  extends from plunger to valve ball interface  47 , downstream through plunger channel  53  and integrally connects to piston  54 . In this exemplary embodiment, plunger  52  is monolithically formed as a feature of piston  54 . A piston guide  64  is formed as an integral feature of regulator body  44  and is dimensioned slightly smaller than piston skirt inside diameter thereby preventing an interference fit. These stated dimensions allow piston  54  to freely move along guide  64  as well as allowing means for fluid passage between plunger channel  53  and a piston bore  60 , also formed as an integral part of regulator body  44 . 
     In use, the pressure contained in piston bore  60  on the (bottom) plunger side of piston  54  will be defined as regulated pressure herein expressed as σ 2  (shown in  FIGS. 2 ,  4 ,  5 ,  6 ). Piston  54  freely moves in piston bore  60  aligned by guide  64 , and isolates regulated pressure σ 2  from the topside of piston  54  by piston seal  55 . 
     Located on the topside of piston  54  is a compression piston spring  57 . Piston spring  57  is inserted through the top of regulator body  44 , contacting the top of piston  54  and retained by a cap  58 . Cap  58  comprises a female thread at  67  and correspondingly threads to a male thread at  69  onto integrated threads in regulator body  44 . Cap  58  has grip features molded into the outer diameter enabling an easy grip when adjusting preload on piston spring  57 . Additionally, cap  58  has a large hole  78  in its top that allows a hose (not shown) to be mechanically connected to piston  54  and pass out of regulator assembly  20 . Large hole  78  also allows any pressure on the topside of piston  54  to vent to the atmosphere. 
     Prior to piston  54  bottoming out on a travel limit shelf  61  in piston bore  60 , plunger  52  contacts valve ball  46  at plunger to valve ball interface  47  and opens valve assembly  22 . When valve assembly  22  is open, pressure equilibrium is achieved between lance fluid port  32  which is in pressure equilibrium with compressed gas cartridge  21  ( FIG. 1 ), through valve chamber  45 , all the way downstream to piston bore  60 , contained by the bottom (plunger side) of piston  54  by piston seal  55 . When no compressed gas cartridge is attached to regulator  20 , valve  22  is biased in the open position by the force of piston spring  57 . 
     Upon introduction of a high-pressure fluid from lancing a compressed gas cartridge, that exceeds 800 pounds per square inch pressure at room temperature for carbon dioxide, this fluid travels through valve assembly  22  and creates a new regulated pressure σ 2 , pushing up on piston  54  and piston spring  57 . The selected spring rate of piston spring  57  combined with the pre-loading of piston spring  57  by cap  78  determines regulated pressure σ 2 . A higher spring force creates a higher regulated pressure σ 2 . 
     An exit conduit  62  of regulated pressure σ 2  taps off the top of piston  54 . An alternate exit conduit  73  of regulated fluid pressure could tap into regulator body  44  anywhere downstream from valve assembly  22  within pressurized piston bore  60  contained by piston seal  55  such as through a port in regulator body  44  rather than through the top of piston  54 . Conduit is typical hose barb, NPT (National Pipe) threads, or similar connection and leads to any pneumatic or hydraulic device requiring a regulated, substantially constant working pressure to operate. 
     As regulated pressure σ 2  is tapped off exit conduit  62 , regulated pressure σ 2  decreases, and in effect reduces the pressure contained on the bottom side of piston  54 , allowing piston  54  to move down in piston bore  60  ultimately opening valve assembly  22  with plunger  52 . Opened valve assembly  22  again introduces additional high-pressure fluid through plunger channel  53  and increases the pressure contained by piston  54 , in effect, biasing piston  54  upward in piston bore  60  closing valve assembly  22 , thereby substantially maintaining a consistent regulated pressure σ 2 . 
     An over-pressurization prevention feature  70  is illustrated in  FIGS. 2-6  more specifically comprising a negative vent or plurality of negative vents  72  visible in  FIG. 3 . 
       FIG. 3  illustrates an exemplary over-pressurization feature  70  detailing negative vents  72 , in accordance with an embodiment of the present invention. Preferably, negative vents  72  are arranged in plurality, evenly spaced around piston bore though a single negative vent  72  could still be effective in its function. Piston seal  55  is shown in a sectioned close-up view in its approximate operating position in the regulator bore. Piston  54  ( FIGS. 2 ,  4 - 6 ) is not shown in this view allowing a clear view of internal vent(s)  72  and their relation to piston seal  55 . In the event that regulator valve assembly  22 , ( FIGS. 2 ,  4 - 6 ) fails to retain the high source pressure from compressed gas cartridge  21  ( FIG. 1 ), or excessive pressure is introduced into regulator  20  ( FIGS. 2 ,  4 - 6 ) through exit conduit  62 , the potential exists for excessive pressure to enter piston bore  60 . If this introduction of high pressure were to happen, excessive regulated pressure σ 2  would bias piston  54  upward, overcoming compressed piston spring  57  as pressure and spring force remain in equilibrium. As piston  54  and piston seal  55  translate upward, high pressure is allowed to escape through negative vent(s)  72 . Pressure spikes downstream from regulator  20  that return to piston bore  60  are thus minimized by design. The gradual depth increase of negative vent(s)  72  as vents extend farther away from the resting location of piston seal  55  allow regulator to burp off any excessive pressure without damaging seal  55  due to the gradual transition, and preferably plurality of negative vents  72 . In contrast, if negative vent  72  were simply a through hole (not illustrated) that exits regulator body  44  perpendicular to piston  54  main axis, the likelihood of piston seal  55  to extrude into the exit hole from pressure and tear at the exit hole as the piston moves is greatly increased. In  FIG. 3  a bore height h is shown as a reference for the height that piston seal  55  must travel in order for pressure blow-off to occur and will be explained more fully below. 
     Counting the number of components in the exemplary pressure regulator  20  illustrated in  FIG. 2 , comprises a total of twelve, including cartridge-retaining container  38  and compressed gas cartridge  21  (illustrated in  FIG. 1 ). These components are as follows: 
     Adjuster cap  58   
     Main spring  57   
     Regulator body  44   
     Piston seal  55   
     Sealing ring  48   
     Sealing ball  46   
     Sealing ball spring  50   
     Piercing lance  30   
     Cartridge seal  28   
     Piston  54   
     Cartridge-retaining container  38  ( FIG. 1 ) 
     Non-threaded neck compressed gas cartridge  21  ( FIG. 1 ) 
       FIG. 4  illustrates an exemplary pressure regulator  400  featuring an adjustable height plunger  452 , in accordance with an embodiment of the present invention. Operation is as follows: A threaded plunger  75  mates with a piston female thread  76 . A slot  77  located on the top of threaded plunger  452  allows an operator to thread plunger  452  higher or lower into piston  254 . The purpose of the adjustable plunger height allows the ability for one to tune the regulator to blow off at a desired back-pressure, independent of preload on piston spring  57 . In operation, cap  58  preloads piston spring  57  thus providing a substantially constant spring force on regulator piston  254 . Allowing plunger  452  to be moveable with respect to piston  254 , the relationship between piston equilibrium position (and position of piston seal  55 ) and opening degree of valve assembly  22  can be tailored. Mostly to benefit from this feature is that the blow-off pressure is tunable. Rather than make bore height h ( FIG. 3 ) of the regulator body over-pressurization prevention feature  70  differ in order to achieve vents at differing bore heights h, one species of regulator body  44  comprising negative vent(s)  72  in the same location can be used with tunable piston  254  and plunger  452  to achieve desired blow-off pressures rather than produce a variety of different regulator bodies  44  possessing differing bore height h. 
     In the embodiment illustrated in  FIG. 4 , one more component is added relative to the aforementioned embodiment illustrated in  FIG. 2 , threaded plunger  452 , thus bringing the number of components up from twelve to thirteen (including compressed gas cartridge  21  and cartridge containing retainer  38 , both shown in  FIG. 1 ) but with added tuning capabilities. 
       FIG. 5  details yet another exemplary regulator  500  comprising the capability to dispense compressed gas cartridges possessing a threaded neck or non-threaded neck, in accordance with an embodiment of the present invention. An additional feature to a regulator body  544  differs slightly from regulator body  44  ( FIGS. 2 and 4 ) in that a lance housing  524  is internally threaded. No cartridge-retaining container  38  ( FIG. 1 ) is necessary in order to harness a compressed gas cartridge comprising threads on the cartridge neck is necessary in order to thread into lance housing  524 . A compressed gas cartridge comprising a threaded neck is not illustrated in the FIGS. Similarly, non-threaded neck  26  compressed gas cartridge  21  utilized in conjunction with cartridge-retaining container  38  ( FIG. 1 ) can still be dispensed with regulator body  544 . 
     In the embodiment illustrated in  FIG. 5 , piston  254  and adjustable height plunger  252  share the same user-tunable blow-off pressure benefits as described in the embodiment illustrated and described in  FIG. 4 . 
     The number of components in the exemplary embodiment regulator  500  illustrated in  FIG. 5  comprises twelve components from the elimination of cartridge-retaining container  38  when a threaded neck compressed gas cartridge  21  ( FIG. 1 ) is dispensed. If a non-threaded compressed gas cartridge is to be dispensed utilizing a cartridge-retaining container  38  ( FIG. 1 ), the exemplary assembly comprises thirteen components. 
       FIG. 6  illustrates an exemplary pressure regulator  600  capable of utilizing the least amount of components to function of the illustrated embodiments, in accordance with an embodiment of the present invention. Regulator body  544  comprises an internally threaded lance housing  524  capable of threadably mating to a threaded neck compressed gas cartridge (cartridge not illustrated). Regulator  600  features the same type of piston  54  and plunger  52  as exemplified in the embodiment illustrated and described in  FIG. 2 . 
     When a threaded neck compressed gas cartridge is dispensed, this embodiment comprises eleven components in order to function, including the compressed gas cartridge.