Abstract:
A maple syrup production spout assembly ( 10 ) with a backflow check valve ( 79 ) is disclosed. The spout assembly is designed for use with vacuum-based maple syrup productions systems ( 200 ) and is used to prevent the backflow of sap ( 270 ) into the maple tree ( 100 ) and thus prevent the drying out of the taphole ( 110 ) due to microbial contamination. Certain existing maple production spout assemblies can be retrofitted to form the backflow check valve spout assembly disclosed herein. Methods of using the spout assembly in maple syrup production are also disclosed.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to maple syrup production, and in particular relates to spout assemblies used in vacuum-based maple syrup production systems. 
     BACKGROUND ART 
     Maple syrup production involves drilling holes into (i.e., “tapping”) maple trees, collecting the sap that exudes from the wound, and then reducing or “sugaring” down the sap using reverse osmosis and evaporators to form the final syrup. Details of maple syrup production are described in the publication entitled “North American Maple Syrup Producers Manual” (second edition), produced by Ohio State University, in cooperation with the North American Maple Syrup Council, and edited by Heiligmann, Koelling and Perkins, which is incorporated by reference herein by way of background information. 
     The traditional way of collecting maple sap uses buckets at the tap source. The sap is then collected in a tank and then transported to the “sugarhouse” for processing. Over the years, a variety of specialized hardware has been developed for this task, including both sap spouts and specialized sap collection buckets or bags. For many years, however, the basic techniques of maple syrup and sugar production remained essentially unchanged. 
     More recently, modern syrup producers have replaced the traditional bucket collection system with a tubing system that includes special spouts (usually 5/16″ or 7/16″ diameter) and plastic tubing “droplines” (usually 5/16″ diameter and about 18″ to 36″ in length) connected to the various spouts. The droplines are then connected to lateral lines (also usually formed from 5/16″ diameter plastic tubing) that run between different maple trees. The lateral lines are in turn connected to one or more “main lines” (usually ¾″ to 2″ diameter) that run to the sugar house. Such systems are described in, for example, U.S. Pat. Nos. 2,877,601, 2,944,369, 3,046,698, and 3,057,115, and may either be gravity fed or utilize a vacuum pump to move the sap to a central collection point (e.g., an evaporator in the sugarhouse). 
     The sap flows from the tree through the spout and then through the line system when the pressure within the tree is greater than that in the lines. The line system then conveys the sap to the evaporator. To facilitate the extraction and transportation of the sap from the tree and to the evaporator, some systems use a pump to pull a vacuum within the line system. This increases the pressure differential between the inside of the line system and the tree, thereby increasing the volume of sap flow as compared to that which would naturally occur by gravity. 
     One of the main problems with such a vacuum-based system is the risk of microbial contamination of the taphole. The taphole formed in the tree is a wound. When a tree is wounded, microbes found in the environment (primarily  Pseudomonas  spp.) may colonize the taphole, thereby initiating a natural wound response and the process of “drying out,” which is an industry term for the cessation of sap flow. Thus, once sap exits the tree and becomes contaminated by microbes, it should not be allowed to remain at the taphole or flow back into the tree. If the sap is allowed to move back into the tree, or if the taphole is open to the air within the tubing lines, the microbes will more readily colonize the taphole, initiate the wound-response process, and cause the taphole to dry out and cease yielding sap. 
     The droplines presently used in gravity-based maple syrup production systems help reduce sap backflow. However, in vacuum-based systems, due to the larger pressure gradient, droplines do not adequately prevent sap backflow when the vacuum is interrupted. 
     SUMMARY OF THE INVENTION 
     Current maple syrup spouts do not prevent sap from flowing back into the taphole when used in vacuum-based maple syrup production systems. The spout assembly of the present invention greatly reduces or prevents the backflow of sap into the tree through the use of a backflow check valve. This reduces microbial contamination of the taphole, increases soil-based water uptake by the tree, and increases sap yield for maple syrup production. The spout assembly can be manufactured separately, incorporated (retrofitted) into existing spout assembly designs, or incorporated into a spout assembly adapter that attaches to existing spout assemblies. Maple producers that utilize vacuum-based systems in their operations could benefit from the use of the maple spout assembly of the present invention. 
     A first aspect of the invention is a spout assembly for inserting into a taphole formed in a maple tree as part of a maple syrup production system that utilizes a line system under vacuum to convey sap from the maple tree. The assembly includes an input section defining an input channel and adapted for insertion into the taphole so as to receive a flow of sap from the maple tree, and an output section defining an output channel and configured to fluidly connect the output channel to the line system. The assembly also includes a main body section operably connected to the input and output sections and that defines an interior chamber to which the input and output channels are fluidly connected. The interior chamber contains a backflow check valve configured to substantially prevent the flow of sap in a direction from the output channel to the input channel and to allow the flow of sap in a direction from the input channel to the output channel. 
     A second aspect of the invention is a maple syrup production system that includes the above-described spout with its input end inserted into the taphole, and a line system operably connected to the spout assembly output end and to a vacuum pump that creates a vacuum differential between the line system and the taphole that causes the sap to flow from the taphole and through the spout assembly and through the line system. 
     A third aspect of the invention is a method of extracting sap from a maple tree. The method includes providing a spout assembly having an input end and output end, a main body section having an interior chamber fluidly connected to the input and output ends via respective input and output channels and that contains a backflow check valve that only allows sap to flow through the chamber from the input end to the output end. The method also includes forming a taphole in the maple tree and inserting the spout assembly input end into the taphole. The method further includes applying a vacuum to the spout assembly output end, wherein the application of the vacuum is subject to interruption, and substantially preventing sap that has exited the tree from reentering the tree through the spout assembly via activation of the backflow check valve during the interruption. 
     A fourth aspect of the invention is maple syrup production spout assembly for managing the flow of sap. The assembly includes a main body section defining a chamber that contains a backflow check valve comprising a floating blocking member configured to move within the chamber, and input and output sections having respective input and output channels with respective input and output ends, the input and output channels fluidly connected to the main body chamber. In a first operational state, the floating blocking member resides in first position within the chamber that allows sap to flow in a direction from the input end toward the output end, and in a second operational state the floating blocking member resides in a second position with the chamber that substantially prevents the flow of sap in a direction from the output end toward to the input end. 
     A fifth aspect of the invention is a method of extracting sap from a maple tree. The method includes forming a taphole in the maple tree and inserting a spout into the taphole at a spout input end, wherein the spout has an output end and does not have backflow prevention capability. The method also includes connecting a backflow check valve to the spout output end, wherein the backflow check valve has an input end and an output end that only allows sap to flow in a direction away from the tree. The method further includes applying a vacuum to the spout via the backflow check valve, wherein the application of the vacuum is subject to interruption. 
     Additional features and advantages of the invention are set forth in the detailed description that follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the invention as described herein, including the detailed description that follows, the claims, as well as the appended drawings. 
     It is to be understood that both the foregoing general description and the following detailed description present embodiments of the invention are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the invention, and together with the description serve to explain the principles and operations of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of a vacuum-based maple syrup production system that uses the spout assembly of the present invention; 
         FIG. 2  is a close-up view of an example embodiment of the spout assembly of the present invention as used in the system of  FIG. 1 , and showing an example embodiment of a backflow check valve geometry in the “flow” operational state; 
         FIG. 3  is the same as  FIG. 2 , but illustrating the operation of the backflow check valve in the closed position associated with the “blocking” operational state; 
         FIG. 4  and  FIG. 5  are similar to  FIG. 2  and  FIG. 3 , respectively, and illustrate another example embodiment of a backflow check valve that uses a floating disc; 
         FIG. 6  is a schematic side view of an example embodiment of the maple syrup production spout assembly of the present invention that is formed by retrofitting a commonly used plastic maple syrup production spout assembly; 
         FIG. 7  is an exploded view of an example of the spout assembly of  FIG. 6  wherein the spout assembly comprises a spout section and a mating adapter section; 
         FIG. 8  is a cross-sectional view of spout section taken in the X-Z plane that illustrates an example embodiment wherein the spout assembly of  FIG. 6  includes at least one groove formed in the chamber so as to allow sap to flow through the spout section from the input channel to the output channel; and 
         FIG. 9  is a side view of a spout assembly that includes a spout connected to a backflow check valve, wherein the spout does not include backflow-check capability. 
     
    
    
     DETAILED DESCRIPTION OF INVENTION 
       FIG. 1  shows a schematic diagram of an example maple syrup production system  200  that includes spout assembly  10  connected to tree  100  at a taphole  110  formed therein. Spout assembly  10  is described in greater detail below. System  200  includes a line system  208  that includes a dropline  210 , a lateral line  220  and a mainline  230 . A first end  212  of a dropline  210  is fluidly connected to an output end  66  of spout assembly  10  while the other end  214  is fluidly connected to lateral line  220 . 
     Lateral line  220  in turn is operably connected to mainline  230 , which in turn is operably connected to vacuum pump system  240  that includes a vacuum pump  242 , an extractor  244  and a sap storage tank  246  An evaporator  250  is operably connected to vacuum pump system  240  Vacuum pump system  240 , extractor  244 , storage tank  246  and evaporator  250  are shown as housed in a sugarhouse  260 . System  200  thereby provides vacuum-assisted fluid communication between taphole  110  and evaporator  250  so that sap can flow from tree  100  to the evaporator. It is noted here that “fluid communication” refers to both the sap as a fluid and the air the line system as a “fluid.” Said differently, line system  208  is sufficiently air-tight so that vacuum system  240  can pull a sufficient vacuum (e.g., 15-28 inches of mercury). 
       FIG. 2  is a schematic cut-away close-up side view of an example embodiment of maple spout assembly  10  according to the present invention as used in maple syrup production system  200  of  FIG. 1 . Maple spout assembly  10  in includes a nose section  20 , a main body section  40  that defines an interior chamber  42  therein, and a neck section  60 . In an example embodiment, nose section  20  is tapered to facilitate insertion into taphole  110 . Nose section  20  defines a nose (input) channel  22  having an open distal end  24 , an open proximal end  26 , and a central axis A 1 . Proximal channel end  26  is open to interior chamber  42 . 
     Neck section  60  defines a neck (output) channel  62  having a central axis A 2  and an open distal end  64  and an open proximal end  66 . Output channel  62  is connected to chamber  42  at open proximal end  66 . In an example embodiment, channel central axes A 1  and A 2  intersect within chamber  42  at an angle θ, where angle θ is preferably a right angle or an obtuse angle. Input channel  22  and output channel  62  are fluidly connected via a flow path FP that passes through chamber  42  in first operational state referred to herein as the “flow” or “ON” operational state. 
     Chamber  42  contains a blocking member  70 . In an example embodiment, blocking member  70  is free to move (i.e., “float”) within the chamber generally along the direction of axis A 1 , and is captive within the chamber. Blocking member  70  is preferably sized to be larger than the input channel proximal end  26  and is generally configured so that it can block off (seal) input channel  22  at the proximal end when the blocking member is brought into contact therewith to prevent fluid communication between the input channel and chamber  42  over flow path FP. This geometry represents a second operational state of spout assembly  10 , also called the “blocking” or “OFF” operational state. 
     In one example embodiment, floating blocking member  70  is a ball and input channel proximal end  26  has a frustro-conical shape that accommodates the ball to form a leak-proof seal. In another example embodiment, floating blocking member  70  is a disk and input channel proximal end  26  is flat and accommodates the disc to form a leak-proof seal (see  FIG. 4  and  FIG. 5 ). In an example embodiment, input channel proximal end  26  includes a gasket  72  to help form the leak-proof seal in the blocking operational state. Other shapes and configurations for blocking member  70  are also possible, such as a flap-type member (not shown) that is anchored at one of its end within chamber  42  and that can rotate into place to block off input channel proximal end  26  to prevent the backflow of sap  270 . 
     In an example embodiment of spout assembly  10 , a stand-off member  76  is arranged within chamber  42  to prevent blocking member  70  from moving into a position where it might otherwise block off flow path FP at proximal neck channel end  66 . This arrangement of floating blocking member  70  and stand-off member  76  within chamber  42  forms one type of automatic backflow check valve  79  that allows for only the one-way flow of sap  270  through spout assembly  10  in the direction from nose section  20  towards neck section  60 . Thus, nose distal end  24  constitutes a spout assembly “input end” and neck distal end  64  constitutes a spout assembly “output end.” 
     In a preferred example embodiment, spout assembly  10  is made of plastic (e.g., injection-molded plastic), as is blocking member  70  contained therein. Blocking member  70  may be, for example, a plastic or rubber ball. Other materials suitable for use as spout assemblies for maple syrup taps may also be used. Spout assembly  10  of  FIG. 2  is shown in the flow operational state wherein blocking member  70  rests against stand-off member  76  so that sap  270  can flow through the spout assembly from input end  24  to output end  64  over flow path FP. 
     With reference to  FIG. 1  and  FIG. 2 , in the operation of maple syrup production system  200 , vacuum pump  240  is activated to pull a vacuum in line system  208  to facilitate the flow of sap  270  out of maple tree  100  and into spout assembly input end  24  (see arrows  260 ). In this situation, the pressure differential caused by the vacuum causes blocking member  70  to move into position against stand-off member  76 , thereby placing spout assembly  10  in the flow operational state. This allows sap  270  to flow through input channel  22 , through chamber  42 , around the blocking member  70  contained therein, and then through channel  62  to dropline  210  via flow path FP. Sap  270  then runs through the rest of line system  208  to evaporator  250 . It is noted here that sap storage tank  246  is connected to the evaporator, sometimes with an intermediate stage passing through a reverse osmosis machine (not shown). 
     On those occasions when the operation of vacuum system  240  is interrupted either intentionally or through a system malfunction or shutdown, the pressure differential in system  200  reverses so that there is less pressure in tree  100  than in line system  208 . This causes the flow of sap  270  to reverse so that sap that has left the tree will seek to flow back into the tree. As discussed above, this is disadvantageous because microbes in the sap will initiate a reaction in tree  100  that will cause taphole  110  to “dry out.” 
     With reference now also to  FIG. 3 , to prevent this sap flow reversal from occurring during vacuum interruption, the reversed pressure difference automatically causes blocking member  70  to move along axis A 1  until it forms a seal at input channel proximal end  26 . This places spout assembly  10  in the blocking operational state, which blocks the flow path FP and substantially prevents sap  270  from returning to taphole  110 , thereby substantially preventing the taphole from drying out. The blocking operational state of spout assembly  10  also has the added benefit of facilitating the uptake of water by tree  100  via the soil  102  rather than via dropline  210 . Note also that sap  270  residing in input channel  22  is prevented from flowing back to the taphole because sealing off the input channel at proximal end  26  creates a vacuum within the input channel itself as sap tries to flow back towards input end  22 . Note also that the reverse flow of sap  270  itself will cause blocking member  70  to move to the blocking position within chamber  42 . The reverse flow of sap stops quickly in this case because blocking member  70  moves quickly over the short distance within chamber  42  to move into place against input channel proximal end  26 . 
       FIG. 4  and  FIG. 5  are similar to  FIG. 2  and  FIG. 3 , respectively, and illustrate an example embodiment of spout assembly  10  in the “flow” and “blocking” states, respectively, wherein the spout assembly employs a floating disc-type blocking member  70 . Stand-off member  76  of the disc embodiment includes a number of conduits  77  that allow for the flow path to run through the stand-off member. 
     An example plastic spout assembly  10  that can be retrofitted to form the backflow check valve spout assembly  10  of the present invention is made by the Leader Evaporator Company of Swanton, Vt.  FIG. 6  is a schematic side view of an example embodiment of the maple syrup production spout assembly  10  of the present invention that is a retrofit to the Leader plastic maple syrup production spout assembly. Cartesian X-Y coordinates are shown in  FIG. 6  for the sake of reference. 
     Spout assembly  10  of  FIG. 6  includes a spout section  10 A and a mating adapter section  10 B, as shown in the exploded view of  FIG. 7 . Spout portion  10 A includes its own “nose” portion  20 ′ that mates with adapter portion  10 B, which also constitutes the nose portion  20  of the spout assembly. In an example embodiment, spout assembly  10  of  FIG. 6  is retrofitted with a floating ball type of blocking member  70  that is free to move within a channel-type chamber  42  generally along axis A 1 , i.e., along the +X and −X directions (see arrow  65 ). 
     A groove (not shown in  FIG. 6 ; see, e.g., groove  49  in  FIG. 8 ) in channel-type chamber  42  allows for the sap to move past blocking member  70  in the “flow” operational state when the blocking member is at the rear (i.e., the right-most position in  FIG. 6 ) of the channel-type chamber. Note that in this example embodiment of spout assembly  10 , backflow check valve  79  does require the use of a stand-off member  76 . 
     In the blocking operational state caused by a reversal of the pressure differential between input and output ends  24  and  64  as discussed above, ball-type blocking member  70  moves along axis A 1  in the −X direction from chamber portion  43  until it reaches input channel proximal end  26  and seals off input channel  22 . This cuts off the (reverse) flow path FP, thereby substantially preventing the flow of sap back into taphole  110 . 
       FIG. 8  is a cross-sectional view of spout portion  10 A taken in the X-Z plane that illustrates another example embodiment of spout assembly  10 , wherein the spout assembly of  FIG. 6  includes at least one groove  49  formed in channel-type chamber  42 . Groove  49  connects chamber (channel)  42  to output channel  62  to allow sap  270  to flow past ball-type blocking member  70  even while this blocking member resides in a position within channel  42  that would otherwise close of sap flow through the output channel. 
       FIG. 9  is a side view of a spout assembly  10  that includes a spout  110 ′ connected at its output end  64  to a backflow check valve  10 CV. In this embodiment, spout  110 ′ does not include backflow-check capability of the other spout assemblies  10  as described above and in this sense is a conventional maple spout. 
     In the example embodiment of spout assembly  10  as shown in  FIG. 9 , backflow check valve  10 CV is connected directly to conventional spout  10 ′ at output end  64 , but it can also be connected directly to spout  10 ′ via a section of dropline  120 . Backflow check valve  10 CV includes a body  40  with a chamber  42  that is connected at one end to an input channel  40  and at another end to an output channel  62 . Blocking member  70  is provided within chamber  42 . Stand-off member  76  formed within chamber  42  is configured to prevent blocking member  70  from blocking output channel  62  while also allowing sap  270  to flow through backflow check valve  10 CV when vacuum system  240  is in operation. In an example embodiment similar to that shown in  FIG. 8 , blocking member  70  is formed from part of body  40 , and one or more grooves are provided that allow for sap to flow through chamber  42  in the direction input channel  22  to output channel  62 . 
     This embodiment of spout assembly  10  that employs a conventional maple spout  10 ′ and a backflow check valve  10 CV operably connected thereto allows for the use of conventional maple spouts without having to retrofit the spouts, or to use the spout assembly  10  of the present invention that has built-in backflow-check capability. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.