Abstract:
An eductor for mixing two liquids wherein the eductor includes a closed or non-air gap back flow prevention member. The vacuum profile of the eductor is altered by changing an opening in a passage portion to controllably divert water flow around the venturi tube or diverting the water without the opening. This affords the changing of the vacuum profile without redesigning the entire eductor.

Description:
RELATED APPLICATIONS 
     This patent application is a continuation of and claims priority to U.S. patent application Ser. No. 11/997,641 filed Feb. 1, 2008 and issued on Jun. 7, 2011 as U.S. Pat. No. 7,954,507, which is a 371 national-stage entry application of PCT Application No. PCT/US06/029315 filed on Jul. 27, 2006, which claims priority to U.S. patent application Ser. No. 11/195,052 filed on Aug. 2, 2005. Priority is hereby claimed to all of these patent applications, the entirety of each of which is hereby incorporated by reference. 
    
    
     TECHNICAL FIELD 
     This invention relates generally to apparatus employed in the mixing of chemical concentrate with a diluting liquid. More particularly, it relates to an eductor for drawing chemical concentrate from a container and into the diluting liquid wherein the reduced pressure in the eductor can be easily adjusted. 
     BACKGROUND 
     The use of eductors for mixing chemical concentrates into a stream of liquid to provide a diluted solution is well known. For example, see U.S. Pat. Nos. 5,927,338 and 6,279,598 issued to S.C. Johnson Commercial Markets, Inc., which teachings are incorporated herein by reference. 
     Eductors without an air gap are known. One is described in U.S. Pat. No. 6,240,983. 
     Certain advances in technologies and changes in regulatory communities have given rise to non-air gap means of backflow prevention. One of the new backflow prevention methods is to use an elastomer in a critical path in such a manner that if a back siphonage occurs, the elastomer will seal the path closed, thus preventing backflow. The atmosphere of an enclosed water supply system lends itself well to Herschel-type venturi systems. Vacuum profiles are based on standard inlet lengths, diameters and cone angles, which are proportional to exit throat lengths, diameters and cone angles. To change a vacuum profile requires a redesign of the entire venturi. 
     The prior art does not provide a non-air gap eductor wherein the vacuum profile can be changed without redesigning the entire venturi. 
     The objects of certain embodiments of the invention therefore are: 
     Providing an improved eductor for a mixing and dispensing apparatus. 
     Providing an improved non-air gap eductor. 
     Providing an improved non-air gap eductor wherein the vacuum profile can be changed without redesigning the entire unit. 
     Providing an improved non-air gap eductor of the foregoing type which can be easily retrofitted. 
     Providing an improved non-air gap eductor of the foregoing type which can be manufactured at minimal cost. 
     SUMMARY 
     The foregoing objects are accomplished and the shortcomings of the prior art are overcome by the eductor of this invention which in one embodiment includes a body member providing a longitudinal axis. A flow path extends longitudinally through the body member, the flow path defined by a first flow guide and a second flow guide, the second flow guide constructed and arranged to receive liquid from the first flow guide. A closed back flow prevention member is operatively associated with the first flow guide. A venturi tube is positioned in the flow path for receiving liquid from the second flow guide, the second flow guide and the venturi tube are connected by a passage portion. There is an opening in the passage, the opening is constructed and arranged to produce a desired vacuum in the venturi tube. At least one channel is provided laterally to the longitudinal axis for flowing a liquid concentrate into the venturi tube. The flow path further includes a discharge passage extending from the venturi tube to the outside of the body member. 
     In one aspect the channel includes a check valve and there are present two lateral channels. 
     In another embodiment the eductor includes a body member providing a longitudinal axis. A flow path extends longitudinally through the body member, the flow path defined by a first flow guide and a second flow guide, the second flow guide constructed and arranged to receive liquid from the first flow guide. A closed backflow prevention member is operatively associated with the first flow guide. A venturi tube is positioned in the flow path for receiving liquid from the second flow guide, the second flow guide and the venturi tube are connected by a passage portion. There is an opening in the passage. The second flow guide is defined by a tubular portion extending over the opening in the passage. At least one channel is provided laterally to the longitudinal axis for flowing a liquid concentrate into the venturi tube. The flow path further including a discharge passage extending from the venturi tube to the outside of the body member. The extension of the tubular portion over the opening in the passage is designed to afford a desired vacuum profile. 
     In still another embodiment, the eductor includes a body member providing a longitudinal axis. A flow path extends longitudinally through the body member, the flow path defined by a first flow guide and a second flow guide, the second flow guide constructed and arranged to receive liquid from the first flow guide. A closed back flow prevention member is operatively associated with the first flow guide. A venturi tube is positioned in the flow path for receiving liquid from the second flow guide, the first flow guide and the second flow guide positioned in a spaced relationship so as to divert some of the liquid from the venturi tube to produce a desired vacuum in the venturi tube. At least one channel lateral to the longitudinal axis for flowing a liquid concentrate into the venturi tube. The flow path further including a discharge passage extending from the venturi tube to the outside of the body member. 
     In yet another aspect there is a method of establishing a vacuum profile in a closed back flow prevention eductor which includes modifying the opening in a passage of the eductor. 
     In another aspect the second flow guide and the tubular portion are in the form of a funnel member. 
     These and still other objects and advantages of the invention will be apparent from the description which follows. In the detailed description below, a preferred embodiment of the invention will be described in reference to the full scope of the invention. Rather, the invention may be employed in other embodiments. 
     Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of a type of dispensing equipment with which the new eductor may be used; 
         FIG. 2  is an elevational view of the eductor; 
         FIG. 3  is a sectional view of one embodiment of the invention; 
         FIG. 4  is a sectional view of another embodiment of the invention; 
         FIG. 5  is a partial enlarged view of the embodiment shown in  FIG. 3 ; 
         FIG. 6  is a partial enlarged view of the embodiment shown in  FIG. 5  taken along line  6 - 6 ; 
         FIG. 7  is a view of the components shown in  FIG. 6  with the components displaced; 
         FIG. 8  is a sectional view of another embodiment of the invention; 
         FIG. 9  is a view similar to  FIG. 8  with the embodiment turned 45 degrees; and 
         FIG. 10  is a view similar to  FIG. 9  showing another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , there is shown a schematic diagram for a type of dispensing equipment generally in which the eductor  10  of the invention is employed. The equipment  11  has an enclosure  13  and containers  15  in the enclosure  13  or, possibly, outside the enclosure  13  but connected as shown by lines  19 . Normally, each container  15  is filled with a different liquid  17   a  and  17   b . But as explained below, there may be occasions where it is desirable to have two containers  15  filled with the same liquid  17 . 
     The inlet line  21  of the equipment  11  is connected to a source of water feeding a header  23 . Branch pipes  25  are connected to the header  23  and each branch pipe  25  includes a valve  27  “dedicated” to that pipe  25 . When a particular valve  27  is actuated, water flows through the related eductor  10  and mixes a concentrated liquid  17  with such water to form a dilute solution. Each mixed dilute solution is dispensed through a separate tube  29 . The amount of concentrate introduced to the eductor  10  can be controlled by the valves  32 . 
     As seen in  FIG. 2 , the eductor  10  includes a generally tubular body  33  with two opposing ribs  43  and  44 . It has an inlet end  35  and an outlet section  37 , the latter having an outlet fitting  39  attached thereto. Such fitting  39  has a necked-down portion  41  for connection to outlet tube  29 . 
     As shown in  FIG. 3 , the inlet section  35  of eductor  10  includes a core structure  48  with a barrel  50  surrounded by the ribs  52 . There are fluid outlets  54  at the top of barrel  50  as well as a resilient sleeve  56  and a seal ring  53 . An outer casing  58  surrounds the resilient sleeve and has the vents  60 . These previously described components are illustrated in PCT Application No. PCT/US03/08428, which teachings are incorporated by reference. Their function is described in this patent application and serve as a normally closed siphon-breaking air gap. 
     An outlet passage  61  communicates with a funnel member  64  or first flow guide seated in the conical section  63 . A seal  66  is positioned between the outer casing  58  and the conical section  63 . A second flow guide  67  is connected to the first flow guide  64  and the second flow guide  67  is connected to venturi tube  65  by a passage portion  69  provided by the funnel portion  80  of the first flow guide  64 , the conical section  63 , and the second flow guide  67 . An opening  70  is provided in the passage portion  69  of the second flow guide  67 . 
     Inlet section  35  is interconnected to the tubular body  33  by the connecting portion  62 . It includes input connections  72  and  73  communicating with channels  75  and  76  which in turn communicate with passage  78 . A check valve assembly,  74  preferably of the ball check type, is connected to input connection  73 . It will be seen in  FIG. 3  that check valve assembly  74  is shown on an opposing side from that shown in  FIG. 2 . Also, input connection  72  is shown. 
     The embodiments  10 A,  10 B and  10 C illustrated in  FIGS. 4 ,  8 ,  9  and  10  include many of the same components as described in  FIG. 3 , with similar numbers referring to similar components except with an “A”, “B” or “C” suffix. One of the differences between embodiment  10  and embodiments  10 A,  10 B and  10 C is that in embodiments  10 A,  10 B and  10 C they do not include the funnel member  64 . 
     As best illustrated in  FIGS. 5-7 , embodiment  10  shows the positioning of funnel stem  80  of funnel member  64  over a portion of the opening  70 . The purpose of this is explained in the Operation to follow. 
     Referring to  FIGS. 8 and 9 , eductor  10 B differs from eductor  10 A in the configuration and connection between the first flow guide  64 B and the second flow guide  67 B. Other differences are the one piece molding of outer casing  5813  with ribs  43 B and  44 A and the additional connecting portion  62 B between the inlet section  35 B and venturi section  36 B. 
     As shown in  FIG. 10 , eductor  10 C differs from the other eductors  10 ,  10 A and  10 B in that there is no window in the second flow guide  67 C. Instead the first flow guide  64 C is spaced from the second flow guide  67 C. This provides a diversion of water away from venturi tube  65 C. 
     Operation 
     A better understanding of the eductors  10 ,  10 A,  10 B and  10 C will be had by a description of their operation. Referring first to eductor  10 , and FIGS.  3  and  5 - 7 , it will be connected into the dispensing equipment  11  as previously described in conjunction with  FIG. 1 . Water flows into branch pipe  25  and into inlet section  35 . From there it flows through fluid outlets  54  and between barrel  50  and resilient sleeve  56 . It then flows through outlet passage  61 , into funnel member  64 , after which it flows into passage portion  69 , over opening  70  and into venturi tube  65 . As the water passes into venturi tube  65  it creates a reduction in pressure sufficient to open ball check valve assembly  74  and draw a chemical concentrated from a container  15  into inlet connection  73  and into channel  76 . From channel  76  it is mixed with water flowing through passage  78 . The combined solution of water and concentrate exits through outlet fitting  39  and outlet tube  29  providing a discharge passage as seen in  FIG. 1 . 
     The purpose of ball check valve assembly  74  is to serve as a primer for the vacuum in passage  76  and keep prime on the container  15 . It also prevents pressurized water from source to contaminate concentrate to chemical from inlet  73 . 
     An important aspect of eductor  10  is the positioning of funnel portion  80  in conjunction with opening  70 . This controls the amount of water flowing through the venturi tube  65  and accordingly, the amount of negative pressure created therein. It will be appreciated that the greater the extension of the funnel stem over the opening  70 , the greater the volume of water will flow into the venturi tube  65 , and the greater the negative pressure. Diverted water passes through the opening  70  and forms a secondary stream which passes into the chamber  68  and subsequently into outlet port  71 , whereafter it is combined with the stream of water and chemical concentrate exiting from passage  78 . This concentric flow of the secondary stream and the primary stream through the venturi tube  65  is illustrated in U.S. Pat. No. 5,927,338. It is also described in conjunction with eductor  10 B in  FIG. 9 . 
     Eductors  10 A and  10 B function in substantially the same manner as described for eductor  10 . Instead of funnel stem  80  covering a portion of the opening  70 , the openings  70 A and  70 B are designed with specific dimensions to direct a predetermined amount of water away from the venturi tubes  65 A and  65 B and thus effect a desired vacuum.  FIG. 9  is presented to show the secondary stream which forms as a result of water being diverted from the venturi tube  65 B. The stream will flow outwardly into chamber  68 B and follow the path shown by the arrows until it exits into hose  82 B. At the same time chemical concentrate diluted by the water passing through venturi tube  65 B will exit in tube  83 B. As stated previously, this flow of a primary and a secondary stream of water and diluted chemical concentrate and a secondary stream of water is described in U.S. Pat. No. 5,927,338. 
     The eductor  10 C shown in  FIG. 10  operates without an opening  70 . It relies on the spacing of first flow guide  64 C from the second flow guide  67 C to divert water away from the venturi tube  65 C and thereby create the desired vacuum effect. This is a unique feature as it has never been done before in conjunction with a non-air gap eductor. 
     The siphon-breaking air gap provided by barrel  50  and resilient sleeve  56  operates in the manner described in the previously referred to PCT Application No. PCT/US03/08428. As water flows through fluid outlets  54 , it will expand sleeve  56  and water will flow between the sleeve and barrel  50  into funnel member  64  and ultimately to venturi tube  65 . When there is no flow of water from the water supply  21  and  25 , the resilient sleeve  56  contracts and fits lightly around the barrel  50  to prevent any reverse flow of water. If a siphon action occurs in the water lines  21  and  25 , such as when there is a sudden drop in pressure of the main water supply, the resilient sleeve  56  is already sealed against the barrel  50 , as already discussed. Fluid instead passes into the space between the sleeve  56  and the outer casing  58  and exits through the vents  60 . 
     It will then be seen that there is now provided an eductor wherein the vacuum profile can be changed without redesigning the entire venturi. 
     The eductors  10  and  10 A have been shown with two inlet ports or connections  72  and  73 . If desired, only one could be used as shown in conjunction with eductor  10 B. In that instance, the other would be plugged. Alternatively, the inlet connections can be connected to two containers  15  each with the same liquid chemical concentrate or, alternatively, with different chemical concentrate. Ribs  43 A,  44 A and inlet section  35 A are shown as one piece and outer casing  58  as another. If desired, these could be molded from a suitable plastic material as one piece as indicated in  FIGS. 8 ,  9  and  10 . Other variations and modifications of this invention will be obvious to those skilled in the art. This invention is not to be limited except as set forth in the following claims.