Abstract:
The present disclosure is directed to a valve assembly comprising a housing and a valve mechanism. The housing includes a pair of support rings connected together with a set of legs. The valve mechanism is supported within the housing and includes an open position and a closed position. The valve mechanism is constructed and arranged such that when in the open position, fluid is allowed to flow through the valve mechanism into the housing and exit the housing between the legs. More than four legs extend between the first support ring and the second support ring, the legs arranged circumferentially such that the legs are substantially equally spaced around the housing.

Description:
REFERENCE TO CO-PENDING APPLICATION 
   This patent application claims the benefit of prior U.S. provisional application filed on Mar. 19, 2004, having Ser. No. 60/554,698, and titled “High Temperature Valve Assembly”. 

   BACKGROUND 
   The present disclosure relates to valve assemblies for opening or closing fluid paths. More particularly, the present disclosure relates to valve assemblies, such as check valves, adapted for use with plunger pumps for high temperature and high stress applications such as car washes, and the like. 
   Fluid pumps are often described by the type of motion used, displacement, mechanism, cylinders and pressure. For example, a reciprocating pump converts rotary driving motion from a motor, or the like, to a linear pumping motion with a pumping mechanism. Driving speed of the motor in revolutions per minute is often directly related to the output of the reciprocating pump. A reciprocating positive displacement pump first moves fluids into the pump, and then the fluids are moved out of the pump. Plunger pumps are reciprocating positive displacement pumps that displace a given amount of fluid on each cycle, or stroke, of the plunger. The reciprocating motion of the plunger, with check valves on each side of the pump body, creates the pumping action of the fluid. On the suction stroke, or up stroke, low pressure in the pump body closes a discharge, or outlet, check valve, opens a suction, or inlet, check valve, and pulls fluid into a pump cylinder in one example. On the discharge stroke, or down stroke, high pressure in the pump body closes the suction check valve, opens the discharge check valve, and pushes the fluid out of the pump cylinder in the example. Typically, these pumps include one to six cylinders. A simplex pump may only include one cylinder, but a more common configuration is a triplex pump with three cylinders. When pump forces fluid through a restriction in excess of about 150 pounds per square inch, the pump is often termed a high-pressure pump. 
   Plunger pumps include several advantages, and a few of these advantages are listed here. Plunger pumps provide a constant flow of fluid at high pressures over long periods of time, and they can operate without fluid allowing them to operate unattended. Also, plunger pumps are adapted to vary the amount of flow without having to vary the speed of the drive motor. Also, plunger pumps are durable and can operate in a variety of conditions. Several of the many applications of plunger pumps include septage and sludge, water treatment, desalination, and industrial cleaning such as car wash systems. 
   Car wash systems are a particularly useful and demanding application for plunger pumps. Plunger pumps in car wash systems are typically required to pump water at high temperatures, such as greater than approximately 165 degrees (about 74 degrees Celsius) Fahrenheit and often up to approximately 185 degrees Fahrenheit (about 85 degrees Celsius). These high temperatures sometimes cause premature damage to some of the internal components of the plunger pump, such as the check valves described above. 
     FIG. 1  shows an example of a prior art check valve assembly  10  that is provided here to illustrate how high temperatures sometimes cause premature damage. The check valve assembly  10  includes a housing  12  that surrounds and supports a spring-loaded valve mechanism  13 . The check valve assembly  10  is adapted to permit fluid to flow through the housing  12  when the valve mechanism  13  is open. The valve mechanism  13  includes a spring  14  that biases a valve plate  15  against a valve seat  16 . The housing includes a spring guide  17  that maintains the proper position of the spring  14  within the housing  12 . The housing includes a first support ring  18  distal to the valve seat  16  and a second support ring  19  proximate to the valve seat  16 . No more than four legs  20 , are coupled to and extend between the support rings  18 ,  19 . The legs  20  are spaced-apart around the support rings  18 ,  19 . The legs  20  and support rings  18 ,  19  provide the structural integrity of the valve assembly and are referred to as the valve cage. A stop ring  21  is also included in the valve cage to prevent over-travel of the valve plate  15  and to define a fully open position of the check valve assembly  10 . Water flows between the second support ring  19  and the valve plate  15  and in through a hole  22  in the valve seat. 
   The prior art check valve assembly  10  has proven itself effective in low temperature applications, but it has a tendency to develop stress fractures when used in high temperature applications. Specifically, the stress fractures typically occur on the second ring  19  in between the legs  20  as a result of high temperature applications and fluid cavitation. 
   Initial attempts to correct this problem have failed or have compromised the efficiency of the check valve assembly. For example, one proposed solution by those skilled in the art involved increasing the height of the second ring  19 . This proposed solution failed to prevent stress fractures after testing. Further, the flow characteristics of the check valve assembly were adversely affected and reduced the fluid flow through the housing when the valve plate  15  was in an open position. Another proposed solution by those skilled in the art was to increase the width of each leg  20 . This proposed solution also restricted flow of fluid through the check valve assembly as it narrowed the spacing between each leg. 
   Accordingly, there is a need for a reinforced check valve assembly that resists stress fractures as a result of high temperature applications and fluid cavitation, and that does not reduce fluid flow capacity. The check valve assembly should also be close enough to the external dimensions of existing check valve assemblies so as to be interchangeable in existing plunger pumps. 
   SUMMARY 
   The present disclosure is directed to a valve assembly comprising a housing and a valve mechanism. The housing includes a pair of support rings connected together with a plurality of legs. The valve mechanism is supported within the housing and includes an open position and a closed position. The valve mechanism is constructed and arranged such that when in the open position, fluid is allowed to flow through the valve mechanism into the housing and exit the housing between the legs. More than four legs extend between the first support ring and the second support ring, the legs arranged circumferentially such that the legs are substantially equally spaced around the housing. 
   The check valve assembly of the present disclosure meets the above needs by providing a valve assembly with an improved housing design. In addition to providing the features of the prior art housing, one aspect of the present disclosure provides six rather than four legs. Despite conventional wisdom of those skilled in the art, the six legs do not restrict the flow space from the prior art. The legs in this aspect are narrower than the legs of the prior art. Surprisingly neither the strength of the legs or the strength of the second ring are reduced in this aspect. Rather, the check valve assembly is able to withstand high temperatures and cavitation to retain a longer lifespan than the prior art, and the check valve assembly uses the same valve mechanism components and is interchangeable with existing pumps. 

   
     BRIEF DESCRIPTION OF THE FIGURES 
       FIG. 1  is perspective view of a prior art valve assembly. 
       FIG. 2  is a schematic drawing of an environment of the present disclosure. 
       FIG. 3  is a cross-sectioned plan view of a plunger pump including features of the present disclosure. 
       FIG. 4  is a perspective view of a valve assembly of the present disclosure shown in  FIG. 3 . 
       FIG. 5  is a plan view of the valve assembly of  FIG. 4 . 
   

   DESCRIPTION 
   This disclosure relates to valve assemblies. The disclosure, including the figures, describes the valve assembly with reference to an illustrative example. For example, the disclosure proceeds with respect to a valve assembly used in a plunger pump mechanism of a car wash system described below. However, it should be noted that the present invention could be implemented in other systems or pump mechanisms, as well. The present invention is described with respect to the plunger pump mechanism in a car wash system for illustrative purposes only. Other examples are contemplated and are mentioned below or are otherwise imaginable to someone skilled in the art. The scope of the invention is not limited to the few examples, i.e., the described embodiments of the invention. Rather, the scope of the invention is defined by reference to the appended claims. Changes can be made to the examples, including alternative designs not disclosed, and still be within the scope of the claims. 
     FIG. 2  shows a schematic view of a car wash  23 , which is one example of an environment of the present disclosure. The car wash can include an automatic, manual, or conveyor type car wash. Other types of industrial cleaning systems, or high temperature fluid systems are also suitable for the present environment. The car wash  23  includes a pump  24  coupled to a heated water supply  26  and receives water from the water supply  26 . Typically, the water supply  26  can be heated to approximately 185 degrees Fahrenheit (about 85 degrees Celsius) and the pump  24  is adapted for high temperature conditions, and possibly for high-pressure conditions. The pump  24  provides the water to the nozzles  28  that are adapted to spray the water onto a vehicle  25  in the car wash  23 . 
     FIG. 3  shows a general schematic diagram of a pump  30 , which is an example of pump  24  shown in  FIG. 2 . The pump  30  includes a pump housing  32  and an outlet manifold  34 . A first plunger  35   a , second plunger  35   b  and third plunger  35   c  are illustrated in this example. The plungers  35   a ,  35   b ,  35   c , extend within a first chamber  36   a , second chamber  36   b  and third chamber  36   c , respectively. The chambers, or cylinders, also include seal stacks  38 . The pump  30  has an inlet  40  for providing a supply of fluid, and an outlet  42  for providing the pressurized fluid to subsequent devices, such as the nozzle  28 . In the example, the housing  32  is configured so that housing inlet  40  is in communication with first chamber  36   a , second chamber  36   b  and third chamber  36   c , so that fluid can be provided to each of these chambers. 
   The pump also includes a plurality of check valve assemblies. In the example, two check valve assemblies are coupled to each chamber. A first inlet check valve assembly  44  is disposed proximate the first chamber  36   a  near the inlet. Similarly, a second inlet check valve assembly  46  and a third inlet check valve assembly  48  are disposed proximate the first and second chambers  36   b ,  36   c , respectively. Each chamber  36   a ,  36   b ,  36   c  also has an appropriate outlet check valve assembly. Chamber  36   a  includes a first outlet valve  50 , chamber  36   b  includes a second outlet valve  52 , and chamber  36   c  includes a third outlet valve  54 . 
   Both the inlet valves  44 ,  46 ,  48  and the outlet valves  50 ,  52 ,  54  are one-way pressure activated valves that operate to allow fluid to move one direction while prohibiting its movement in an opposite direction. Fluid is drawn into the first chamber  36   a  when the first plunger  35   a  is in a down, or suction stroke. The negative pressure within the chamber  36   a  causes the inlet check valve assembly  44  to open and fluid enters the chamber  36   a  from the inlet  40 . The negative pressure within the chamber  36   a  also causes the outlet check valve assembly  50  to close, so fluid does not exit the chamber  36   a  into the outlet  42 . Fluid exits the first chamber  36   a  when the first plunger  35   a  is in an upstroke. The positive pressure within the chamber  36   a  causes the outlet check valve assembly  50  to open and fluid exits the chamber  36   a  into the outlet  42 . The positive pressure within the chamber  36   a  also causes the inlet check valve assembly  44  to close, so fluid does not enter the chamber  36   a  from the inlet  40 . The details of the check valve assemblies are described below. 
     FIG. 4  shows a perspective view of the check valve assembly  60  that corresponds to and is a detailed view of inlet check valve assemblies and outlet check valve assemblies in  FIG. 3 . Check valve assembly  60  includes housing  62  that surrounds and supports a spring-loaded valve mechanism  64 . The check valve assembly  60  is adapted to permit fluid through flow through the housing  62  when the valve mechanism  64  is open. 
   The valve mechanism  64  includes a spring  66  that biases a valve plate  68  against a valve seat  70 . The valve plate  68  in the example does not include a stem, i.e., stemless, and can float freely within the housing. The spring  66  in the example is a coil spring that is disposed around a spring guide  72  that is coupled to the housing  62  to maintain the proper position of the spring  66 . The spring  66  urges the valve plate  68  toward the valve seat  70 . The valve seat  70  includes an annular member  71  on an outer face. The annular member  71  is adapted to accept an O-ring to help seal the valve assembly against the plunger pump. The annular member  71  also defines a passage  73  in the valve seat  70 . Fluid can enter valve assembly  60  through the passage  73  and then pass into the housing. The valve assembly  60  is in a closed position when the valve plate  68  is urged up against the valve seat  70  to cover the passage  73 , and the valve assembly  60  is in an open position when the valve plate  68  is spaced apart from the valve seat  70  by fluid pressure allowing fluid to pass through the passage and into the housing  62 . 
   The housing  62  includes a plurality of support rings  74 ,  76  and more than four spaced-apart legs  78 , that form a valve cage  75 . The valve cage  75  provides the structural integrity of the valve assembly  60 . The first support ring  74  is distal to the valve seat  70 , and the second support ring  76  is proximate the valve seat  70 . The first and second rings  74 ,  76  are generally co-axially located on the housing around the coil spring  66 . The first and second rings  74 ,  76  are generally in parallel planes to one another. The legs  78  extend axially and are connected to the first and second rings  74 ,  76 . In the example shown, the housing includes six legs  78 , although a valve housing including five or more legs is contemplated. In the example shown, the valve seat  70  is snap-fit within the second support ring for easy assembly. The housing  62  also includes a stop ring  80  that is coaxially located with the first and second rings  74 ,  76  and between them. The stop ring  80  is connected to the legs  78  at an intermediate portion. The stop ring  80  is included in the housing  62  to prevent over-travel of the valve plate  64  and to define a fully open position of the check valve assembly  60 . Fluid flows around the legs  78  between the second support ring  76  and the valve plate  68  and in through the passage  73  in the valve seat  70 . 
     FIG. 5  is a plan view of the check valve assembly  60  taken along line of sight  82  in  FIG. 4 . The legs  78  in the example are spaced-apart at equal angular intervals. In this case, the centers of the legs are spaced apart at approximately sixty-degree intervals. The width of the legs  78 , as indicated at  84 , is approximately one-seventh of the diameter of the passage  73 . Further, the maximum distance between the valve plate  68  and the second support ring  76 , in this example, is about the width of the legs, or about one-seventh of the diameter of the passage  73 . The example shows the legs  78  to have approximately equal thickness. It is contemplated that the thickness of the legs can vary, in which case the average thickness of the plurality of legs can be used to calculate the appropriate dimensions of the valve assembly. The described dimensions of the valve assembly  60  in the example provides the appropriate flow capacity while structural support to withstand high temperature applications and still be sized to fit within existing pumps. 
   In one example, the valve cage is constructed from a material including a polyamide resin and fiberglass. One suitable polyamide resin is polyamide 11, such as that sold under the trade designation RILSAN, available from the Arkema Group of Paris, France, with locations throughout the world. In the example where the valve cage is constructed out a material including polyamide 11 and fiberglass, the fiberglass content is approximately six percent of the material. This material along with the design of the example provides a valve housing  62  resistant to damage from high temperature applications. 
   The present invention has now been described with reference to several embodiments. The foregoing detailed description and examples have been given for clarity of understanding only. Those skilled in the art will recognize that many changes can be made in the described embodiments without departing from the scope and spirit of the invention. Thus, the scope of the present invention should not be limited to the exact details and structures described herein, but rather by the appended claims and equivalents.