Patent Publication Number: US-8534208-B2

Title: Product conveyance system for an agricultural implement

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a divisional of application Ser. No. 12/493,827 filed Jun. 29, 2009 now U.S. Pat. No. 8,234,987. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a product conveyance system for conveying product in an agricultural environment and, more particularly, relates to a planting implement with an improved inductor assembly for conveying seed and other particulate material to a planting unit for application in an agricultural environment. 
     BACKGROUND OF THE INVENTION 
     In recent years, agricultural implements have employed forced air conveyance systems to deliver seed, fertilizer and herbicides. As the size of these agricultural implements continues to grow, the versatility of such implements becomes more significant. In particular, large air carts or air seeders have become increasingly popular for conveying seed, fertilizer and other product without strict regard for the exact placement of the product. Typically, these large air carts are used for dry land farming (e.g., cereal crops, etc.). 
     For certain crop planting applications that require row crop planting or seed singulation (e.g., corn, soybean, etc.), the air cart can be combined with an inductor assembly adapted to feed seed or other product from a larger storage hopper into smaller reservoirs located at on-row planting units, also referred to as singulators or receivers. The combined air cart and inductor assembly enables a farmer to singulate planting of seeds on-row from one central hopper filling location. Thereby, the nurse inductor assembly and air cart allows a farmer to plant more acreage before having to stop to fill the central hopper again, resulting in quicker planting and less labor while maintaining the precision spacing available by on-row singulation. 
     U.S. Pat. No. 6,253,693 discloses a nurse inductor assembly in flow communication with a storage hopper of seed mounted on an air cart. The air cart includes a fan to provide a forced air stream through the inductor assembly. The forced air stream is directed by the inductor assembly to a general location of a seed mass delivered from the storage hopper. The forced air stream engages the seed mass, entraining the seed into the air stream. A movable seed control gate is configured to regulate an angle of repose of a surface of the seed mass, which affects the entrainment of the seed into the forced air stream. The inductor assembly conveys the combined stream of forced air and seed through a series of inductor sections that each leads to an isolated inductor distribution tube and ultimately to a distribution line leading to associated series of remote receivers for application of the seed in an agricultural field. When the receiver is full of seed, the air stream is restricted from escaping the receiver and ultimately reduces the capacity of the air stream at the inductor assembly to induce the seed into the inductor distribution tubes. 
     This nurse inductor assembly has several drawbacks. For example, the velocity of the combined stream of air and seed product through the distribution line slows as the stream encounters the increased resistance associated with traveling through the deposited seed product at the receiver. If allowed to be induced into the distribution lines below the minimum carrying velocity, the seed product causes blocking of the seed distribution lines. Any seed product that had been entrained into the slower flowing air stream drops out under the force of gravity. A certain quantity of dropped seed product will deposit toward low points in the distribution lines, increasing plugging opportunities. Another drawback of this nurse inductor assembly is that the movable gate is difficult to adjust for various products of different sizes and properties, which can cause uneven product flow to the receivers and/or plugging opportunities in the inductor assembly or distribution lines. Also, the interference of the seed control gate to the flow of the combined stream of air and seed will cause the seed to bridge across the inductor chamber of the inductor apparatus and inhibit the entrainment of seed into the forced air stream. 
     U.S. Pat. No. 7,222,029 to Johnson et al., and assigned to CNH America, LLC, the assignee of the present application, and the disclosure of which is incorporated herein by reference, describes an inductor assembly for a product conveyance system that overcomes many of the drawbacks of prior art inductor assemblies or “inductor boxes” such as that described in the &#39;693 patent. More particularly, the patent to Johnson et al. describes an inductor assembly for forced air conveyance of product that provides sufficient carrying capacity to convey seed through a distribution line to a remotely located receiver. 
     Notwithstanding the benefits provided an inductor assembly such as that described by Johnson et al., there remains a need for uniformity of the combined stream of air and product across the inductor assembly and into the distribution lines. That is, many inductor assemblies contain a series of inductor segments, with each inductor segment generally comprised of an upper conduit and a lower conduit. Each conduit has a respective inlet and a respective outlet, and each inlet is designed to receive a combined product and forced air stream that is passed through its corresponding outlet. In a typical configuration, the length of the conduits is not uniform, which can result in a pressure differential across the profile of the inductor segments. In general, the flow rate through the shorter conduits is greater than the flow rate through the longer conduits. As a result, more product may be conveyed through some distribution lines than conveyed through others, which can ultimately lead to an uneven distribution of product to the individual on-row units. 
     SUMMARY OF THE INVENTION 
     The present invention provides an inductor assembly configured to be attached in flow communication to receive a flow of product from a storage hopper of a product conveyance system. The product conveyance system further includes a forced fluid source operable to provide a forced fluid stream to the inductor assembly. The inductor assembly includes an inductor housing configured to receive a flow of product from the storage hopper. The inductor housing includes an inlet configured to direct a first portion of the forced fluid stream in a path to engage the flow of product so as to generate the combined stream of forced fluid and product. The inductor assembly further includes multiple inductor segments, wherein each inductor segments defines at least one conduit having an inlet and an outlet. The inlet of the at least one conduit is located to receive the combined stream of forced fluid and product 
     The present invention therefore is directed to an apparatus for controlling the flow rate through the various conduits such that a desired flow rate pattern in a single inductor segment or across multiple inductor segments is realized. In one preferred implementation, one or more of the conduit inlets is fitted with an orifice plate having an opening through which the combined forced air and product stream may be passed. The inlets fitted with such an orifice plate have a restricted air flow characteristic when compared to those inlets not fitted with such an orifice plate. Thus, through judicious use of such orifice plates, a desired air flow profile for the inductor assembly, or individual inductor segments, can be defined. 
     In one preferred embodiment, the inductor segments associated with shorter distribution lines are fitted with such orifice plates to slow down the flow rate characteristic of the shorter distribution lines and therefore provide for a more uniform air flow velocity across the distribution lines. The size of the opening in the orifice plate can be selected based on the amount of air flow restriction that is desired. Furthermore, the orifice plates may be machined with the conduit inlets or take the form of an insert that is secured to the inlets. 
     The conduits of a single inductor segment may have orifice plates at each inlet or, alternately, only one of the conduits of the inductor segment may have an orifice plate depending upon the desired flow rate characteristics for the inductor segment. For that matter, one or more of the inductor segments of the inductor assembly may not be fitted with any orifice plates and thus the flow rate characteristics of the distribution lines for those inductor segments would be unchanged. 
     In a further preferred inductor assembly, motive air, such as that provided by a fan, is provided to the inductor assembly through an upper air inlet and a lower air inlet. Air received through the upper air inlet is designed to increase the volume of air that is provided to the distribution lines and air that passes through the lower air inlet is designed to fluidize product into the air stream that is created by the air that passes through the upper air inlet. In this preferred inductor assembly, an air flow restrictor is mounted to the inductor assembly and is designed to alter the size of the lower air inlet across the width of the lower air inlet. The restrictor, which in one form is a restrictor plate mounted to the inductor assembly generally adjacent the lower air inlet, reduces the size of the lower air inlet at certain points along the lower air inlet. This effectively restricts air flow through certain portions of the lower air inlet to reduce the air flow rate through those certain portion of the lower air inlet. 
     Therefore, in accordance with one aspect of the invention, an inductor segment is provided that defines a first conduit and a second conduit, the first conduit having a first inlet and a first outlet, and the second conduit having a second inlet and a second outlet. The second outlet of the second conduit is stacked above the first outlet of the first conduit, and in a like manner, the second inlet of the second conduit is generally stacked above the first inlet of the first conduit. One of the inlets has an opening through which the combined forced air and product stream passes that is sized differently than the opening of the other one of the inlets. Thus, air flow through the one inlet, relative to the other one of the inlets, is restricted. 
     In accordance with another aspect of the invention, an inductor assembly is provided for conveying product in a storage hopper of a planting implement for application in an agricultural field. The planting implement includes a forced fluid source operable to provide a forced fluid stream. The inductor assembly includes an inductor housing configured to receive the flow of product from the storage hopper. The inductor housing includes an inlet to direct the forced fluid stream in a direction toward the flow of product so as to generate the combined stream of forced fluid and product. The inductor assembly further includes a first inductor segment that defines at least one first conduit in flow communication to receive the combined stream of forced fluid and product generated in the inductor housing. The inductor assembly also includes at least one second inductor segment that defines at least one conduit in flow communication to receive the combined stream of forced fluid and product generated in the inductor housing. The at least one first conduit has a first inlet and the at least one second conduit has a second inlet. The sizes of the first and the second inlets are different such that the flow rate through the first and the second inlets are different from one another. 
     According to another aspect of the invention, a mobile air cart includes a product conveyance system configured to distribute a supply of product in an agricultural environment. The product conveyance system includes a hopper configured to contain the supply of product, a forced air source operable to provide a stream of force air, a distribution system, and an inductor assembly. The distribution system is configured to convey a combined stream of product and forced air to a planting unit for application of the product in the agricultural environment. The inductor assembly is configured to generate the combined stream of forced air and product. The inductor assembly includes an inductor housing configured to receive a flow of product from the storage hopper. The inductor housing includes an inlet configured to direct a first portion of the forced air stream in a path to engage the flow of product delivered from the storage hopper in such a manner as to generate the combined stream of forced fluid and product. The inductor assembly further has a first inductor segment that defines at least one conduit having an inlet and an outlet and at least one second inductor segment also defining at least one conduit having an inlet and an outlet. The inlet of the first conduit is located in flow communication to receive the combined stream of forced fluid and product. Similarly, the inlet of the second conduit is located in flow communication to receive the combined stream of forced fluid and product. The inlet of the first conduit has an inlet size that is different than the inlet size of the inlet of the second conduit. Thus, the flow rates through the first and second inlets differ from one another. 
     Other objects, features, and advantages of the invention will become apparent to those skilled in the art from the following detailed description and accompanying drawings. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred exemplary embodiments of the invention are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout. 
         FIG. 1  schematically illustrates a side elevation view of an air cart in combination with an inductor assembly in accordance with one aspect of the present invention. 
         FIG. 2  schematically illustrates a front view of a planter associated with the air cart and inductor assembly of  FIG. 1 . 
         FIG. 3  schematically illustrates an isometric view of the inductor assembly of in  FIG. 1 . 
         FIG. 4  schematically illustrates a detailed cross-sectional view of the inductor assembly along line  4 - 4  in  FIG. 3  in combination with the storage hopper. 
         FIG. 5  schematically illustrates an interior view of the inductor assembly shown in  FIG. 3 , with a portion of the inductor housing removed. 
         FIG. 6  schematically illustrates a front elevation view of the inductor assembly shown in  FIG. 4 . 
         FIG. 7  schematically illustrates a front elevation view of the inductor assembly shown in  FIG. 4  with a lower air inlet cover removed. 
         FIG. 8  schematically illustrates an exploded view an inductor segment of the inductor assembly shown in  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A wide variety of inductor assemblies for conveying product with forced fluid, e.g., air, could be constructed in accordance with the invention defined by the claims. Hence, while preferred embodiments of the invention will now be described with reference to a product conveyed by an air cart, it should be understood that the invention is in no way so limited. The type of conveyance system or machine (e.g., air seeder, row-crop planter, spreader, etc.) can vary. The description generally refers to use of the present invention to convey product, and the invention can be utilized to convey a wide variety of product (e.g., seed, fertilizer, herbicide, pesticide, etc.) and is not limiting on the invention. In addition, the type and size of the product (e.g., soybean, corn, cereal grains, fertilizer, herbicide, etc.) can vary. 
       FIG. 1  illustrates an inductor assembly  10  of a product conveyance system in accordance with present invention configured to be pulled by a tow vehicle (not shown) in a forward direction of travel (illustrated by arrow  12 ). The exemplary embodiment of the product conveyance system is a planting implement that includes a conventional air cart  14  in combination with a planter  16  ( FIG. 2 ). The air cart  14  generally includes a main or central storage hopper  18 , and a pressurized or forced air source  20 . The forced air source  20  (e.g., blower fan, etc.) is operable to provide a stream of pressurized air (illustrated by arrow  22 ) to the inductor assembly  10 . Although the inductor assembly  10  is illustrated in combination with an air cart  14  and a planter  16 , it is understood that the type and configuration of the planting implement can vary. For example, the inductor assembly  10  can be mounted with the forced air source  20  on the planter  16 . 
     Still referring to  FIG. 1 , the inductor assembly  10  is generally configured to direct or guide the stream of forced air (shown by arrow  22 ) provided from the forced air source  20  into a path that engages the product fed from the storage hopper  18 . The forced air stream conveyed from the forced air source  20  into to the inductor assembly  10  pressurizes the inductor assembly  10 , as well as agitates the product accumulating in the inductor assembly  10 . The turbulence of the forced air stream agitates the accumulation of the product, separating and entraining the product into the air stream. 
     The forced air stream also creates a vacuum in the inductor assembly  10  such that the combined stream of forced air and entrained product shown by arrow  22  is swept toward and into one or more distribution lines  24  that lead to the planter  16  ( FIG. 2 ). The planter  16  includes a distribution or receiver header  26  in communication with one or more planting units  28  (See  FIG. 2 ). The distribution lines  24  will typically have varying lengths to accommodate the variable spacing of the planting units  28  from the storage hopper  18 . The planting unit  28  generally includes a receiver or mini-hopper  30 . The individual seed product remains suspended or entrained in the air stream while passing through the receiver header  26  to the planting unit  28 . In another embodiment of the planter  16 , the combined stream of forced air and entrained product may pass from the one or more distribution lines  24  directly to one or more planting units  28 . In a known manner, the air bleeds off through an air vent (not shown) at the planting unit  28 , and the entrained individual seed product falls by gravity into a second pile or mass at the receiver or mini hopper  30 . The planting unit  28  is thereafter operable to singulate the product for application into a furrow in the ground. 
     Although the illustrated inductor assembly  10  is shown mounted on the air cart  14 , the inductor assembly  10 , the hopper  18 , and/or the forced air source or combination thereof can be mounted on the planter  16  and is not limiting on the invention. 
     At the inductor assembly  10 , the product is suspended and carried away by the forced air stream only when the velocity of the forced air stream is above the minimum carrying velocity to entrain the product in the air. A forced air stream velocity below the minimum carrying velocity will allow gravity to deposit or remove the product from the air stream. 
     The inductor assembly  10  generally includes an inductor housing  32  configured to enclose a series of inductor segments  34 . As shown in  FIG. 4 , the inductor housing  32  is mounted underneath and in flow communication with the storage hopper  18  of the air cart  14 . The preferred inductor housing  32  generally includes an air inlet  36  to receive the forced air stream  22  from the forced air source  20 . As shown in  FIG. 3 , an access door  38  is pivotally coupled to allow access to the interior of the inductor housing  32 , as well as to empty the contents of the inductor housing  32 . The access door  38  is pivotally mounted by a pivot pin  40  located at the rearward end of the inductor housing  32 . A low profile latch mechanism  42  is provided to selectively secure the access door  38  in a closed position against the inductor housing  32 . In securing the access door  38  in the closed position the latch mechanism  42  is configured to engage structure  44  mounted on the access door  38 . 
     As illustrated in  FIGS. 3-6 , the series of inductor segments  34  are located side-by-side along a lateral width of the inductor housing  32 . Each inductor segment  34  in combination with the housing  32  defines a nozzle region  46  that directs the forced air stream along a flow path that tangentially engages the pile of product supplied from the hopper  18  at the rearward end of the series of inductor segments  34 , relative to the forward direction of travel. 
     Referring to  FIGS. 4 and 5 , the forced air stream  22  received at the inlet  36  of the inductor assembly  10  is spread across the entire series inductor segments  34 . The nozzle regions  46  defined by the inductor segments  34  generally split the air stream  22  at the general location where the product is delivered from the storage hopper  18  of the air cart  14  to the inductor assembly  10 . Optionally, a vane, such as that described in U.S. Pat. No. 7,222,029, may be located forward of the nozzle regions  46  of the inductor segments  34  and positioned at an angle with respect to horizontal. U.S. Pat. No. 7,222,029 teaches that a vane may enhance the smooth transition of the flow path of the forced air stream from the inductor inlet  36  toward the pile of product that enhances the air to product ratio, and thereby enhances the efficiency of the forced air stream in suspending the product in the forced air stream. 
     Each inductor segment  34  generally includes a first product tube  48  and a second product tube  50 . The first product tube  48  includes a first inlet  52  and a first outlet  54 , and the second product tube  50  includes a second inlet  56  and a second outlet  58 . The outlets  54  and  58  of the first and second product tubes  48  and  50 , respectively, are connected in flow communication with distribution lines that lead to associated receiver headers  26  and receivers  30  (see  FIG. 2 ). The first and second product tubes  48  and  50  of each inductor segment  34  thereby split the air and entrained product flow to different receivers  30  associated with the respective distribution lines  24  connected to the first and second product tubes  48  and  50 . The first and second product tubes  48  and  50  thus prevent a crossover of the combined stream of forced air and entrained product between the different distribution lines  24  and associated receivers  30 . The split or division of the combined stream of forced air and product by each inductor assembly  34  enhances operation of the receivers  30  because each distribution line  24  is operable to run at different times, depending on demand as represented by the level of the product amassed at the associated receiver  30 . The forced air stream is split in accordance to the demand of the respective receivers  30 , as the forced stream of air tends to go to the inductor segments  34  and associated distribution lines  24  in communication with receivers  30  having a lower airflow resistance. 
     As illustrated in  FIG. 4 , a cross-sectional area of each of the first and second product tubes  48  and  50 , respectively, is greater relative to a cross-sectional area of the associated distribution lines  24 . Thereby, the velocity of the combined stream of forced air and product increases upon entering the distribution line  24  above the minimum carrying velocity of the product so as maintain suspension of the product in the forced air stream through the distribution line  24  to the receiver  30  (See  FIG. 2 ). 
     The first and second product tubes  48  and  50  of each inductor segment  34  direct the air and entrained product stream with relatively small directional changes so as to enhance the efficiency to the forced air source  20 . The first product tube  48  and the second product tube  50  of each inductor segment  34  are generally aligned in a modular configuration such that the first inlet  52  of the first product tube  50  is adjacent to the second inlet of the second product tube  50 , and the outlet  58  of the second product tube  50  stacks on top of the outlet  54  of the first product tube  48 . The vertical nature of this modular design of each inductor segment  34  enhances the compactness of the inductor assembly  10 . This modular design configuration also allows the inductor assembly  10  to be readily adapted to different widths and numbers associated with the number of distribution lines  24  and/or receivers  30 . The first and second outlets  54  and  58  and respective distribution lines  24  attached thereto are stacked in generally vertical pairs that optimize space beneath the air cart  14 . 
     In operation, the inlet  36  of the inductor housing  32  of the inductor assembly  10  receives the forced air stream from the forced air source  20 . The nozzle regions  46  of the series of inductor segments  34  guide the forced air stream in path toward the pile of product delivered from the storage hopper  18 . The forced air stream strips away product from the pile of product into suspension in the forced air stream, and the storage hopper  18  replenishes product to the created cavity in the pile of product. The closer to the bottom of the inductor housing  32  that the product is stripped away, the more quickly the product is replenished. 
     If the forced air stream velocity falls below the carrying velocity of the product, any seed particles that had been entrained into the slow flowing air stream fall out of the airflow and are dropped back into the pile of product. Thus, the seed particles are picked up and carried by the air stream only when the velocity of the forced air stream is above the minimum carry velocity, thereby allowing the forced air stream to flow without transporting any entrained product into the product tubes  48  and  50  of each inductor segment  34 . 
     The distribution or receiver header  26  splits the combined stream of air and product among multiple receivers  30 . As an alternate configuration, the combined stream of air and product may be sent directly to the receivers without being split. The receivers  30  are designed to separate the product the forced air stream and product and allow the forced air to readily escape when the level of product is below a predetermined vent level, and limits the amount of the forced air stream to escape when the product level is above the predetermined vent level. The more steady that a rate of the product is induced into the forced air stream, the more reduction in plugging opportunities in the distribution lines  24  and the greater the efficiency of the forced air source  20 . 
     The inductor housing  32  has air inlet  36  that receives the forced air stream. The air inlet  36  is in flow communication with an upper air inlet  36 ( a ) and a lower air inlet  36 ( b ). In accordance with one preferred embodiment, a cover plate  60  is removably mounted to the inductor housing  32  by fasteners  62 , which in the illustrated embodiment are wing nuts although; other types of fasteners may be used. When the cover plate  60  is removed, a restrictor plate  64  is exposed, as shown in  FIG. 7 . The restrictor plate  64  is fitted within the inductor housing  32  generally adjacent the lower air inlet  36 ( b ). The restrictor plate  64  is designed to restrict air flow through the lower air inlet  36 ( b ). The restrictor plate may have one of a number of different configurations to affect the flow of air through the lower air inlet  36 ( b ). In the illustrated embodiment, the restrictor plate  64  has a flange  66  that tapers from one end of the lower air inlet  36 ( b ) to the opposite end of the lower air inlet  36 ( b ). Thus, air flow through the lower air inlet  36 ( b ) is restricted in a generally linear fashion from one end of the lower air inlet  36 ( b ) to the opposite end of the lower air inlet  36 ( b ). 
     With additional reference to  FIG. 8 , one or more of the product tubes may be fitted with an orifice plate  68  having an opening  70  through which the combined forced air and product stream may pass. The orifice plates(s)  68  are designed to restrict air flow through the product tubes. In one preferred embodiment, orifice plates(s)  68  are fitted to one or more of the first product tubes. That is, product tubes  48  associated with shorter distribution lines  24  are fitted with orifice plates to counteract the increased airflow through the shorter distribution lines relative to the airflow through the longer distribution lines. In this regard, orifice plate  68 ( a ) may be used to create more uniformity in flow rates between the various distribution lines. As shown in  FIG. 8 , the inlets  52  and  54  each have a recessed seat  72 ,  74 , respectively, against which the orifice plates  68 ( a ) and  68 ( b ) sit. Further, it will be appreciated that orifice plate  68 ( a ) has a smaller opening  70 ( a ) than the opening  70 ( b ) of orifice plate  68 ( b ). Thus, orifice plate  68 ( a ) is more flow restrictive than orifice plate  68 ( b ). 
     It will be appreciated that the orifice plates may be machined with the product tube inlets or may take the form of a separate component that is fitted within the inlets. In one preferred embodiment, the inlets have a seat against which the orifice plates sit and a suitable sealant or other fastening means is then used to secure the orifice plate in place. Additionally, it is contemplated that the orifice plates may be removed and replaced with other orifice plates having differently sized openings to change the flow rate through the product tubes. 
     The embodiment of the inductor assembly  10  described above is described in combination with the standard air cart  14  having the hopper  18  and the pressurized air source  20 . Although the above-description referred to the inductor assembly  10  combined with an air cart  14 , it is understood that the inductor assembly  10  of the present invention is adaptable for use with a stand-alone blower and product storage tank or vessel, as well as adapted for incorporating with other types of agricultural implements. Furthermore, the above-described embodiment of the inductor assembly  10  of the invention can be constructed integrally with an air cart  14 , or as a modular unit that can be coupled to a standard air cart structure to convert the air cart  14  into a inductor-type of planter. 
     Furthermore, one skilled in the art will recognize that the present invention can be used to convey numerous types of products (e.g., seed, fertilizer, herbicides, pesticides, etc.) that exhibit suitable properties for forced air conveyance. Furthermore, the typical air cart  14  can be provided with multiple hoppers containing different types of products for application in an agricultural environment. For example, one hopper could have seed product stored therein, while another tank would have fertilizer and yet another tank could have herbicides or still another reservoir of fertilizer. In such multi-tank configurations, one of the tanks could be provided with the inductor assembly  10  to convey seed product to the planting devices, while another inductor assembly  10  is used to control the flow of fertilizer or other product to the planting devices. Thereby, the forced air source  20  on the air cart  14  can be used for both fertilizing and seed planting operations simultaneously. Furthermore, the combined air cart  14  and inductor assembly  10  can be used to apply the fertilizer or other product at a variable rate as controlled by an electronic controller, as is known for precision farming techniques. Other alternative configurations can include one inductor assembly  10  operable to convey seed product to all the receivers  30  (e.g., singulator), as well as multiple inductor assemblies  10  operable to convey seed product to any one particular receiver  30 . 
     Many changes and modifications could be made to the invention without departing from the spirit thereof. The scope of these changes will become apparent from the appended claims.