Abstract:
A dispensing system for mixing at least first and second components and dispensing an expanding foam is disclosed. The system includes separate vessels, each containing a foam component, and a dispensing apparatus. The dispensing apparatus includes a cartridge assembly mounted on a body assembly. The cartridge assembly includes a mix chamber and first and second ports, each for supplying a foam component to the mix chamber. A pair of adjusting valves is mounted to the cartridge assembly with each valve operable to adjust the flow of each foam component to the mix chamber. A pair of hoses connects the vessels to the cartridge assembly. Each adjusting valve is a variable orifice device in the cartridge assembly having the capability of varying the flow area of the port. The present invention also includes a method for adjustably controlling, at the dispensing apparatus, the flow of each of the first and second components to the mixing chamber to alter their ratio therein. Additionally, the throughput of the dispensing apparatus can be controlled by the variable orifice devices.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority from Provisional Application Serial No. 60/354,714, filed on Feb. 8, 2002, which is incorporated herein in its entirety by reference. 
    
    
     STATEMENTS REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     REFERENCE TO A MICROFICHE APPENDIX 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a system, apparatus and method for mixing and dispensing foams and, more particularly, to a system, apparatus and method for mixing and dispensing expanding foams employing an adjustable orifice flow regulating device for controlling the composition of the resulting foam. 
     2. Description of the Related Art 
     Various foam dispensing systems and apparatuses, including guns, have been proposed and used for mixing and dispensing synthetic foams, including such expanding synthetic foams as polyurethane or polyisocyanurate foams. Typically, preparation of an expanding synthetic foam requires the uniform mixing of two fluid components. For example, in a polyurethane foam, one component is a polyol component, referred to as the B component, and the other component is an isocyanate component, referred to as the A component. The A and B components may include one or more other agents, including, but not limited to, foaming agents, curing agents, catalysts or accelerators. The A and B components are conventionally stored in separate containers prior to use. Typically, the two components are combined in the mixing chamber of a dispensing apparatus or dispensing gun to create the expanding foam. When the two components are mixed in proper proportions, they typically react quickly to form and solidify into the expanding foam. 
     Current methods of regulating the ratio of these streams leverage the control of the viscosity of the chemicals and/or the pressure of each component stream. Controlling the viscosity of the chemical components typically requires the application of heat. Such a method of stream control is generally undesirable due to its cost. Controlling component streams with pressure has its own problems in that to change the pressure of the chemical components in a conventional system, the operator must take the gun back to the area where the chemical tanks and the pressure controls are located to make adjustments to the pressures and flow rates of the chemicals. In order to make these adjustments, each of the chemical vessels connected to the dispensing gun commonly employ separate pressure controls so that their respective pressures may be independently adjusted. 
     It is desirable to be able to regulate the ratio of the chemical component streams of a foam component mixing apparatus quickly and easily. It is also desirable to be able to regulate the ratio of the chemical components at the dispensing apparatus. It is also desirable to be able to vary the throughput of the dispensing apparatus at the apparatus. 
     SUMMARY OF THE INVENTION 
     The present invention includes a method, apparatus and system for mixing and dispensing chemical component streams of a foam component wherein regulating the ratio of the chemical component streams is quick and easy and controlled at the dispensing apparatus. Additionally, the present invention allows the operator to control the throughput at the dispensing apparatus. 
     The dispensing system for mixing first and second components and dispensing an expanding foam preferably includes separate vessels containing each foam component and a dispensing apparatus. The dispensing apparatus preferably includes a cartridge assembly mounted on a body assembly. The cartridge assembly further preferably includes a mix chamber and first and second ports, each port for supplying a foam component to the mix chamber. A pair of adjusting valves is also preferably mounted to the cartridge assembly with each adjusting valve operable to individually adjust the flow of each foam component to the mix chamber. A pair of hoses preferably connects the component vessels to the cartridge assembly. Each adjusting valve preferably includes a variable orifice device in the cartridge assembly operable to vary the flow area of the port. The present invention further includes a method for adjustably controlling, at the dispensing apparatus, the flow of each of the first and second foam components to the mixing chamber such that the ratio of the foam components therein may be easily altered and controlled. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The objects, advantages, and features of the invention will become more apparent with reference to the drawings appended hereto and wherein like numerals indicate like parts and wherein an illustrated embodiment of the invention is shown, in which: 
     FIG. 1 is an elevation view of a foam dispensing system formed in accordance with teachings of the present invention; 
     FIG. 2 is an elevation view, partially in section, of a dispensing apparatus formed in accordance with teachings of the present invention; 
     FIG. 3 is a view taken along lines  3 — 3  of FIG. 2; 
     FIG. 4 is a view taken along lines  44  of FIG. 3; 
     FIG. 5 is a partial view, in section, of an adjustable orifice valve formed in accordance with teachings of the present invention; and 
     FIG. 6 is an exploded view of a portion of an embodiment of a dispensing apparatus formed in accordance with teachings of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The dispensing system of the present invention, designated generally as  20  in FIG. 1, is described below with reference to the drawings. The present invention is particularly well suited for mixing and dispensing expanding foams, such as polyurethane and polyisocyanate foams, and is generally described below in this context. However, the present invention has other applications that may be appreciated by those skilled in the art and, as such, it is to be understood that application of the present invention is not limited to expanding foams. 
     Referring to FIG. 1, one embodiment of an expanding foam dispensing system  20  is shown. The expanding foam dispensing system  20  preferably includes a foam dispensing apparatus or dispensing gun  22  operable to mix and dispense chemical reactants used in forming an expanding foam, such as a polyurethane or polyisocyanate foam. The foam dispensing system  20  also preferably includes vessels  24  and  26 , each for separately storing the chemical reactants A and B, respectively, commonly used in forming the polyurethane foam. A source  28  is preferably connected to the vessels  24  and  26  and is generally employed for the transfer of the chemical reactants in the vessels  24  and  26  to the foam dispensing gun  22 . As shown in FIG. 1, the source  28  may be a pressurized source, such as a tank of pressurized nitrogen, having a regulating valve  25  operably coupled thereto. An alternative source  28  may consist of a pump assembly (not expressly shown) operable to pump the foam components from the vessels  24  and  26  to the dispensing gun  22 . 
     The chemical reactants or foam components for a polyurethane foam are typically a liquid polymer resin designated as component B and an isocyanate compound designated as component A. Components A and B are typically supplied to the dispensing gun  22  through suitable hoses or feed lines  27  and  29 . In many foam dispensing systems, hoses or feed lines  27  and  29  may range from between one-hundred (100) to two-hundred (200) feet in length. 
     Still referring to FIG. 1, the foam dispensing system  20  may also include a supply hose  21  from the source  28  to the dispensing gun  22 . In the embodiment shown in FIG. 1, the supply hose  21  preferably provides compressed air or nitrogen from the source  28  to operate an air piston-type foam dispensing gun  22 . In an alternate embodiment, the air piston-type dispensing gun  22  may be powered by a compressed air source that is separate from the source  28 . In yet another embodiment, the dispensing gun  22  of the present invention may be a mechanically-operated dispensing gun. In an embodiment of the present invention in which a mechanically-operated dispensing gun is used, there is generally not a need for the supply hose  21  coupling the source  28  to the dispensing gun  22 . In addition, the chemical vessels  24  and  26  may themselves be pressurized such that it is not necessary to employ the pressurized source  28  in the system  20  or a compressed air source that is separate from the source  28 . Both air piston-type dispensing guns and mechanically-operated dispensing guns are known in the art. Teachings of the present invention include an improvement to dispensing guns and are applicable to both air piston and mechanically-operated dispensing guns. 
     Referring now to FIG. 2, an enlarged view of an air piston-type dispensing gun  22  is shown. The air piston dispensing gun  22  generally includes several features described in assignee&#39;s U.S. Pat. No. 5,163,584. Applicant herein incorporates by reference U.S. Pat. No. 5,163,584 as to the components of the disclosure describing the common features of the dispensing gun  22 . 
     As shown in FIG. 1, the supply hose  21  preferably supplies compressed air or other pressurized gas from a source  28  to the dispensing gun  22  through a suitable regulating valve  23 . The feed lines  27  and  29  supply foam components A and B to a carrier assembly  30  of the dispensing gun  22  as shown in FIG.  3 . Referring to FIGS. 2 and 6, the dispensing gun  22  preferably also includes a handle assembly  36 , an air cylinder assembly  40 , and a cartridge assembly  44 . The primary components of the dispensing gun  22  may be fabricated from any suitable wear resistant material which is chemically inert with respect to the components to be mixed. Suitable materials include, but are not limited to, aluminum, aluminum alloys, steel and copper alloys, and plastics such as acetal resin, epoxy, glass-filled epoxy, nylon and glass-filled nylon. 
     Referring to FIG. 2, the air cylinder assembly  40  may be secured to an upper end  46   a  of a handle body  46  of the handle assembly  36 . Preferably, a carrier body  52  is releasably secured to the upper end  46   a  of the handle body  46 . As shown in the embodiment of FIG. 6, the carrier body  52  may include one or more holes  52   a  therethrough aligning with corresponding holes  46   b  in the upper end  46   a  of the handle body  46 . Preferably, threaded fasteners  52   b  extended through the holes  52   a  and engage the holes  46   b  to secure the carrier body  52  to the handle body  46 . Further, a cartridge body  56  is preferably releasably secured to the carrier body  52 , as, for example, with a threaded fastener  60  and an associated nut  58 . The nut  58  is shown as a thumbnut in the embodiment of FIG. 6 for ease of installation and removal. 
     Although not expressly shown, the air cylinder assembly  40  preferably includes a sliding piston and cylinder. During operation, the piston is pneumatically driven by compressed air from the supply hose  21  in response to depression of a trigger  37  included on the handle assembly  36 . Alternate means for operating the air cylinder assembly  40  may be appreciated by persons having skill in the relevant art and, as such, are contemplated within the scope of the present invention. 
     The construction and details of an embodiment of the carrier assembly  30  and the cartridge assembly  44  are described in further detail with reference to FIGS. 2-6. It is to be understood that the present invention is not restricted to the illustrated carrier and cartridge assemblies  30  and  44 , respectively, but the present invention contemplates a variety of configurations and shapes of these assemblies. The cartridge assembly  44  is generally constructed in the manner described in U.S. Pat. No. 5,163,584. The cartridge assembly  44  preferably includes the cartridge body  56  having a mixing or mix chamber  48  (FIGS.  2  and  4 ). The cartridge body  56  is preferably formed of stainless steel, metal, or other such suitable material which will not be chemically attacked by the polymer resin, polyisocyanate, or polyurethane foam. Further, the material chosen for the cartridge body  56  is preferably capable of withstanding any mechanical stresses typically imparted thereon. 
     As shown in FIG. 2, the cartridge body  56  preferably includes a longitudinal cavity  62  for receiving a core  64 . The core  64  is preferably formed from or at least coated with Teflon or a similar, suitable material. The core  64  preferably also includes a longitudinal bore  64   a  extending therethrough. The core  64  is generally confined within the longitudinal cavity  62 . An opening  68   a  is also preferably included and generally extends through a wall  68  in the cartridge body  56 . Preferably, a nozzle  70  having a bore  70   a  is releasably coupled to the discharge end of the cartridge body  56 . 
     Still referring to FIG. 2, a slide rod  72  longitudinally extends into the cartridge body  56  and is slidably received in an interference fit within the longitudinal bore  64   a  of the core  64 . The slide rod  72  is preferably adapted to releasably connect to a piston rod  42  of the air cylinder assembly  40 . 
     Referring now to FIG. 4, where portions of the dispensing gun  22  are shown cut away, the cartridge assembly  44  preferably includes a pair of apertures  74  extending radially therethrough and providing gas and/or fluid communication between the exterior of the cartridge body  56  and the longitudinal bore  64   a  of the core  64 . It is to be understood that only one of the pair of apertures  74  is shown in FIG. 4 due to the way the section was taken (see FIG.  3 ). That is to say, the left portion of FIG. 4 reflects the right portion of FIG. 4 with the only difference being that the left portion generally depicts a cut-away view of various components. Accordingly, it is to be understood that a second aperture  74  extends radially down and to the right similar to the aperture  74  shown extending down and to the left in FIG.  4 . 
     As shown in FIG. 4, an inlet member  76  may be inserted in the aperture  74  of the cartridge body  56 . It is to be understood that the pair of apertures  74  generally provide for the entry of the A and B components into the longitudinal bore  64   a  of the core  64  or the mixing chamber  48 . Enabling the A and B components the enter the mixing chamber  48  through the respective apertures  74  permits the expanding foam to be mixed and formed therein. As disclosed in U.S. Pat. No. 5,163,584, the apertures  74  are preferably arranged with respect to one another generally to enable the optimum mixing of the components. 
     Also as shown in FIG. 4, the cartridge body  56  is preferably arranged such that the apertures  74  may be positioned in communication with the fluid passageways  78  formed in the carrier body  52 . As discussed above, it is to be understood that a fluid passageway  78  is present on both the left and right sides of the carrier body  52  although expressly shown on only the left side of FIG.  4 . 
     Referring to FIGS. 4 and 5, each fluid passageway  78  preferably communicates with an enlarged passageway  80 . Each enlarged passageway  80  generally intersects with a substantially longitudinal passageway  82  (FIG. 3) extending to the rear  30   a  of the carrier assembly  30 . 
     Referring again to FIG. 4, a pair of valve bores  84  (illustrated generally on the right side of FIG. 4) intersect with the longitudinal passageways  82 . An on-off control valve  86  for the A component and an on-off control valve  88  for the B component are preferably inserted in the pair of valve bores  84 . The valves  86  and  88  are preferably sealingly attached to the carried assembly  30 . For example, FIG. 6 shows an O-ring  87  for providing a seal. On-off control valves  86  and  88  are preferably operable to permit or prevent the flow of foam components A and B, respectively, into the respective enlarged passageways  80 . With reference to FIGS. 3 and 4, the valve  86  includes a handle  86   a  for rotating a shaft  86   b  having a port  86   c  therethrough. In the “on” position the port  86   c  aligns with the passageway  82  (FIG.  3 ), and in the “off” position the port  86   c  is generally transverse to the passageway  82  and the shaft  86   b  prevents the flow of the foam component. The valve  88  is similarly constructed and operated. 
     As shown in FIG. 3, hoses  27  and  29  are preferably threadedly connected to the longitudinal passageways  82  at the rear  30   a  of the carrier assembly  30 . Thus, in the illustrated embodiment the A and B components are supplied to the mixing chamber  48  from the pressurized vessels  24  and  26  via the hoses  27  and  29  to the carrier assembly  30  through the on-off control valves  86  and  88  and then through the apertures  80  and  78  into the longitudinal bore  64   a.    
     Referring now to FIGS. 3-5, a pair of adjustable orifice valves, preferably needle valves,  90  and  92  are preferably threadedly connected to each enlarged passageway  80  (FIG. 4) of the carrier body  52 . Preferably, the adjustable orifice valves  90  and  92  include a needle  94  having a tapered nose  94   a  adapted to sealingly engage the fluid passageways  78  when in a closed position. FIG. 4 shows the adjustable orifice valve  92  in a substantially closed position. In the closed position, the foam component or fluid will generally not be able to pass through passageway  78  nor enter the mixing chamber  48 . In FIG. 5, the adjustable orifice valve  90  is shown in a fully open position which generally allows full flow of a foam component through the passageway  78 . It is to be understood that the adjustable orifice valves  90  and  92  enable the dispensing gun operator to make fine adjustments to the ratio of the A and B components of the dispensing gun  22  rather than at the source  28  or the foam component vessels  24  and  26 , to achieve the desired results. In the embodiment of FIG. 6, a seal ring  95   a  and a filter screen  95   b  may be used for sealing and filtering of each of the foam components. As an alternate embodiment, a single adjustable orifice valve may be used to control one of the foam component streams, and thus control the ratio of that foam component stream relative to the second component stream. 
     Thus, the dispensing gun  22  of the present invention combines in the mix chamber  48  two separate foam component streams, such as liquid polyurethane chemical, which, when mixed together, react to form a polyurethane foam or elastomer. The preferred embodiment of the present invention preferably incorporates an adjustable orifice valve for each foam component stream which is conveniently located in the dispensing gun  22  to generally provide the following benefits: 
     1. The operator may make ratio adjustments without going back to the source of the chemicals or foam components. This capability eliminates the operator needing to take the dispensing gun back to the area in which the foam component vessels are located to make adjustments on the flow rate. Consequently, with the new adjustable orifice valves  90  and  92  of the present invention, the operator may adjust the foam component flow at the dispensing gun  22  itself, thereby eliminating the need to drag the dispensing gun  22  back to the area where the tanks  24  and  26  are located. 
     2. The adjustable orifice valves  90  and  92  of the present invention permit the operator to control and vary the throughput of the dispensing gun  22 . A high throughput or output is obtained with the valves  90  and  92  fully open whereas a low output is obtained with the valves slightly open. Thus, when desired to adjust the rate of throughput, the operator can make the adjustment right at the dispensing gun  22 . 
     3. The extra expense of pressure regulating equipment can be cut in half (only one pressure control device  25  is needed as shown in FIG.  1 ). In many conventional systems, each of the two foam component vessels connected to the dispensing gun typically have separate pressure controls such that their respective pressures may be independently varied. With the new adjustable orifice valves  90  and  92  of the present invention, both foam component vessels may be pressurized using a single pressure control device  25 . 
     4. The variable size of the orifice valves  90  and  92  generally eliminates the need to have varied sizes of fixed ratio orifice mix chambers. The new adjustable orifice valves  90  and  92  of the present invention permit the dispensing gun operator to use one mix chamber with a high output flow rate, then reduce the flow rate with the adjustable orifice valves  90  and  92 . The new adjustable orifice valves  90  and  92  of the present invention also permit the adjustment of foam component flow from the maximum allowable flow to negligible or zero flow. 
     5. The present invention may also be useful with currently available disposable kits which utilize a molded plastic dispenser gun having fixed orifices. The chemical tanks provided with these disposable kits are typically pre-pressurized and sealed. The pressure in these tanks generally cannot be adjusted by the operator. However, there are instances when the flow of the chemicals or foam components through the plastic gun may be altered by a partial blockage, or incorrect pressure on the sealed tank. By using a dispensing gun equipped with the adjustable orifice valves  90  and  92  of the present invention, the operator may adjust the chemical or foam component flow on either the A component or B component, despite the inability to alter the pressure on the tanks directly. 
     As should be apparent from the above discussion, the present invention is not limited to the embodiments described and disclosed in the figures. Instead, the present invention may be incorporated in numerous other types and configurations of dispensing apparatus and systems. The present invention provides many advantages over the conventional systems and dispensing apparatus. 
     The description given herein is intended to illustrate a preferred embodiment of the present invention. It is to be understood that the present invention should not be unduly limited to the foregoing embodiment which has been set forth for illustrative purposes. Various modifications and alterations of the invention will be apparent to those skilled in the art, and such modifications and alterations may be made without departing from the true scope of the invention. Therefore, it is intended that all such variations be included within the scope of the present invention as claimed herein.