with reference to fig1 a and fig1 b , a metering apparatus 100 is shown in which flow of agricultural product from a hopper 150 to an air distribution line 190 may be blocked by an inflatable balloon 105 between a meter roller 110 and an outlet 130 to the air distribution line 190 . the metering apparatus 100 comprises the meter roller 110 , in this case a pegged meter roller although any suitable meter roller ( e . g . a smooth roller , fluted roller or high output roller ) may be employed , disposed within a metering chamber 106 of a meterbox 107 . the metering chamber 106 is in communication with the hopper 150 via an inlet 115 so that the agricultural product in the hopper 150 can flow into the metering chamber 106 . the agricultural product collects on a floor 109 of the metering chamber 106 and engages with the meter roller 110 . as seen in fig1 b , when the balloon 105 is deflated , rotation of the meter roller 110 , in this case clockwise rotation , meters the agricultural product at a regulated rate up and over a lip 112 proximate an end of an inclined portion 113 of the floor 109 to exit the metering chamber 106 through the outlet 130 into the air distribution line 190 , which carries the agricultural product to product application outlets for distribution in a field . when it becomes desirable to cut off flow of the agricultural product to the air distribution line 190 , the balloon 105 may be inflated by directing air flow ( or some other gaseous or liquid medium ) into the balloon 105 . air for inflating the balloon may be provided by the same or different source as the air for the air distribution line . for example , an air compressor or other type of compressive device may be provided to inflate the balloon with any suitable gaseous or liquid medium . decompression may be accomplished by letting the medium vent into the environment . the balloon naturally retracts and decompresses to its deflated state . the balloon 105 comprises an external knob 104 that engages and seals against the lip 112 of the floor 109 of the metering chamber 106 when the balloon is inflated thereby sealing the outlet 130 away from the meter roller 110 so that the agricultural product cannot be metered through the outlet 130 even though the meter roller 110 continues to rotate . deflating the balloon 105 disengages the knob 104 from the lip 112 to once again permit the agricultural product to flow over the lip 112 through the outlet 130 and into the air distribution line 190 . the balloon 105 is made from a sufficiently flexible material , for example an elastomer such as natural or synthetic rubber , to permit inflation and deflation of the balloon . the knob 104 may be made of the same or different material as the balloon 105 . the knob 104 is preferably made of sufficiently flexible material to form a suitable seal with the lip 112 . both the balloon 105 and the knob 104 are preferably made of sufficient durable material to be able to resist the flow of agricultural product from a constantly rotating meter roller and to withstand repeated inflations and deflations . the balloon 105 may be secured in the metering chamber 106 by attaching base 103 of the balloon to a wall of the metering chamber 106 . when the balloon 105 is inflated as shown in fig1 a , agricultural product moved as a result of the meter roller 110 constantly rotating may travel up the side of the balloon 105 . to prevent agricultural product from overtopping the balloon 105 and falling down the other side , a duct may be provided to recycle the agricultural product back to the hopper 150 from the metering chamber 106 . further , a pressure equalizing duct 155 is provided for venting out air from above the meter roller 110 when the air distribution fan is turned off . furthermore , to be able to access the inside of the metering chamber 106 to effect maintenance , repair , cleaning or the like of the metering apparatus , a removable gate 170 may be included over an aperture in one of the walls of the metering chamber 106 . removing the removable gate 170 provides access to the inside of the metering chamber 106 through the aperture in the wall of the metering chamber 106 . with reference to fig2 a , fig2 b , fig2 c , fig2 d , fig2 e and fig2 f , a metering apparatus 200 is shown in which flow of agricultural product 220 from a hopper 250 to an air distribution line ( not shown ) may be blocked by a meter roller 210 protruding into the hopper 250 and forming a seal with the hopper 250 at an inlet 215 from the hopper 250 into a metering chamber 206 . the metering apparatus 200 comprises the meter roller 210 , in this case a smooth surfaced meter roller although any suitable meter roller ( e . g . a pegged roller , fluted roller or high output roller ) may be employed , disposed within the metering chamber 206 of a meterbox 207 . the metering chamber 206 is in communication with the hopper 250 via the inlet 215 so that the agricultural product 220 in the hopper 250 can flow into the metering chamber 206 when the meter roller 210 does not block the inlet 215 . the hopper 250 comprises first and second roller plates 251 , 252 having end surfaces 253 , 254 , respectively , that are configured to abut or almost abut the arcuate outer surface 211 of the meter roller 210 . the roller plates 251 , 252 are secured to an inside wall of the hopper 250 and flank the inlet 215 , protruding partially into the inlet aperture 215 . when the meter roller 210 is in a closed position a seen in fig2 a and fig2 b , the end surfaces 253 , 254 of the roller plates 251 , 252 , respectively , are abutting or in close proximity to the arcuate surface 211 of the meter roller 210 so that there is insufficient space between the arcuate surface 211 and the end surfaces 253 , 254 to permit agricultural product 220 from entering the metering chamber 206 from the hopper 250 . at the same time , the arcuate surface 211 may not actually touch the end surfaces 253 , 254 or may only touch slightly so that the meter roller 210 can continue to rotate or to accommodate surface features on the meter roller , e . g . pegs , in which case a brush may be disposed at the inlet to prevent product from flowing when the meter roller is in the closed position . to open the inlet as shown in fig2 d and fig2 e , the meter roller 210 may be pivoted downward by rotation of a driven sprocket 265 geared to a gear 217 on a roller shaft 213 on which the meter roller 210 is mounted . pivoting of the meter roller 210 causes the arcuate surface 211 to move away from the end surface 253 of the first plate 251 thereby opening a gap 219 between the arcuate surface 211 of the meter roller 210 and the end surface 253 of the first plate 251 . the gap 219 permits the agricultural product 220 from the hopper 250 to enter the metering chamber 206 and to be metered down at a regulated rate to outlet 230 at the bottom of the metering chamber 206 by the rotating meter roller 210 , which in this case is rotating clockwise . further , varying the width of the gap 219 provides an opportunity to change the rate of metered product , permitting changes for various sizes and rates of agricultural product in addition to being able to vary the speed of the meter roller 210 . the outlet 230 is in communication with the air distribution line , which carries the agricultural product 220 to product application outlets for distribution in a field . the sprocket 265 and shaft 213 are configured so that pivoting of the meter roller 210 does not appreciably change the distance between the arcuate surface 211 and the end surface 254 of the second plate 252 . reversing the pivoting motion of the meter roller 210 causes the gap 219 to close between the arcuate surface 211 and the end surface 253 of the first plate 251 thereby preventing flow of the agricultural product 220 from the hopper 250 to the metering chamber 206 . with reference to fig3 a , fig3 b , fig3 c , fig3 d , fig3 e and fig3 f , a metering apparatus 300 is shown in which flow of agricultural product 320 from a hopper 350 to an air distribution line ( not shown ) may be blocked by an endless belt 311 of a belt meter 310 that may form a seal with the hopper 350 at an inlet 315 from the hopper 350 into a metering chamber 306 . the metering apparatus 300 comprises the belt meter 310 , in this case a smooth belt although any suitable belt ( e . g . a pegged belt or fluted belt ) may be employed , disposed within the metering chamber 306 of a meterbox 307 . the metering chamber 306 is in communication with the hopper 350 via the inlet 315 so that the agricultural product 320 in the hopper 350 can flow into the metering chamber 306 when the endless belt 311 of the belt meter 310 does not block the inlet 315 . the hopper 350 comprises first and second belt plates 351 , 352 having end surfaces 353 , 354 , respectively , that are configured to abut or almost abut the outer surface of the endless belt 311 of the belt meter 310 . the belt plates 351 , 352 are secured to an inside wall of the hopper 350 in the inlet 315 leaving a sufficiently sized aperture for the agricultural product 320 to flow through the inlet 315 . when the belt meter 310 is in a closed position a seen in fig3 a and fig3 b , the end surfaces 353 , 354 of the belt plates 251 , 252 , respectively , are abutting or in close proximity to the outer surface of the endless belt 311 of the belt meter 310 so that there is insufficient space between the outer surface of the endless belt 311 and the end surfaces 353 , 354 to permit agricultural product 320 from entering the metering chamber 306 from the hopper 350 . at the same time , the outer surface of the endless belt 311 may not actually touch the end surfaces 353 , 354 or may only touch slightly so that the endless belt 311 can continue to rotate or to accommodate surface features on the endless belt , e . g . pegs , in which case a brush may be disposed at the inlet to prevent product from flowing when the belt meter is in the closed position . the belt meter 310 comprises the endless belt 311 looped around driven pulley 323 and idler pulley 324 . the driven pulley 323 is mounted on drive shaft 313 and the idler pulley 324 is mounted on idler shaft 314 . the inside surface of the endless belt 311 and the outside surface of the pulleys 323 , 324 may comprise mated engagement elements 326 , 327 that engage each other to assist with preventing slippage of the endless belt 311 when the endless belt 311 is being driven . slippage would be problematic for the regulated metering of agricultural product 320 by the belt meter 310 . in alternate embodiments , the shaft 314 may be driven and the shaft 313 may be an idler or both shafts may be driven . to open the inlet as shown in fig3 d and fig3 e , the belt meter 310 may be pivoted downward about driven shaft 313 . pivoting of the belt meter 310 in this way causes the outside surface of the endless belt 311 to move away from the end surface 353 of the first plate 351 thereby opening a gap 319 between the outside surface of the endless belt 311 and the end surface 353 of the first plate 351 . in addition , the belt meter 310 becomes downwardly inclined toward the side of the inlet 315 at which the gap 319 has opened . the gap 319 permits the agricultural product 320 from the hopper 350 to flow through the inlet 315 on to the endless belt 311 , which in this case is rotating clockwise , to be metered at a regulated rate by the belt meter 310 through the metering chamber 306 down to outlet 330 at the bottom of the metering chamber 306 . further , varying the size of the gap 319 provides an opportunity to change the rate of metered product , permitting changes for various sizes and rates in addition to being able to vary the speed of the belt meter 310 . the outlet 330 is in communication with the air distribution line , which carries the agricultural product 320 to product application outlets for distribution in a field . reversing the pivoting motion of the belt meter 310 causes the gap to close between the outer surface of the endless belt 311 and the end surface 353 of the first plate 351 thereby preventing flow of the agricultural product 320 from the hopper 350 to the metering chamber 306 . with reference to fig4 a , fig4 b , fig4 c , fig4 d , fig4 e and fig4 f , a metering apparatus 400 is shown in which flow of agricultural product 420 from a hopper 450 to an air distribution line ( not shown ) may be stopped from entering the air distribution line by lowering the agricultural product 420 in a metering chamber 406 away from a continuously turning meter roller 410 to disengage the agricultural product 420 from the meter roller 410 . the metering apparatus 400 comprises the meter roller 410 , in this case a pegged meter roller although any suitable meter roller ( e . g . a smooth roller , fluted roller or high output roller ) may be employed , mounted on shaft 417 and disposed within the metering chamber 406 of a meterbox 407 . the metering chamber 406 is in communication with the hopper 450 via the inlet 415 so that the agricultural product 420 in the hopper 450 can flow into the metering chamber 406 . the agricultural product 420 collects on a floor 409 of the metering chamber 406 and engages with the meter roller 410 . as seen in fig4 d and fig4 e , when the floor 409 of the metering chamber 406 is in a raised position , rotation of the meter roller 410 , in this case clockwise rotation , meters the agricultural product 420 at a regulated rate up and over a lip 412 proximate an end of an inclined portion 413 of the meterbox 407 to exit the metering chamber 406 through an outlet 430 into the air distribution line , which carries the agricultural product 420 to product application outlets for distribution in a field . when it becomes desirable to cut off flow of the agricultural product 420 to the air distribution line , the floor 409 of the metering chamber 406 is lowered proximate the lip 412 as seen in fig4 a and fig4 b . the metering chamber 406 comprises a trough portion 401 , the trough portion 401 comprising side walls , the floor 409 and a back wall 402 hingedly secured to the hopper 450 ( or an immovable part of the meterbox 407 ) by a hinge 427 proximate the inlet 415 . allowing the trough portion 401 to swing counter - clockwise around the hinge 427 ( in the configuration depicted in fig4 d and fig4 e ) causes the floor 409 to become lower proximate the lip 412 as seen in fig4 a and fig4 b . because the floor 409 proximate the lip 412 is now lower , the meter roller 410 cannot engage the agricultural product 420 resting on the floor 409 thereby stopping flow of agricultural product 420 over the lip 412 and stopping flow of agricultural product 420 into the outlet 430 . to prevent agricultural product 420 from slipping between the inclined portion 413 of the meterbox 407 and the floor 409 when the floor 409 is in the lowered position , the floor 409 comprises a matching inclined portion 403 that slides along the inclined portion 413 maintaining a seal between the metering chamber 406 and the exterior of the meterbox . further , to ensure that the metering chamber 406 doesn &# 39 ; t simply fill up with agricultural product 420 to the level of the meter roller 410 when the floor 409 is in the lowered position , an inlet guard plate 418 depending down from the hopper 450 into the metering chamber 406 is configured to be long enough that the end of the inlet guard plate 418 is at the level of or lower than the lip 412 . to bring the agricultural product 420 back into contact with the meter roller 410 , the trough portion 401 is swung in the reverse direction to raise the floor 409 back to the height depicted in fig4 d and fig4 e . the trough portion 401 may be raised and lowered by an actuator , for example a linear actuator or a hydraulic cylinder , connecting the trough portion 401 to the hopper 450 . as shown in fig4 d , fig4 e and fig4 f , the actuator may be secured to the outside of the hopper 450 at attachment 455 and to the outside of the back wall 402 of the trough portion 401 at attachment 405 . with reference to fig5 a , fig5 b , fig5 c , fig5 d , fig5 e and fig5 f , a metering apparatus 500 is shown in which flow of agricultural product 520 from a hopper 550 to an air distribution line ( not shown ) may be stopped from entering the air distribution line by raising a meter roller 510 away from the agricultural product 520 in a metering chamber 506 to disengage the agricultural product 520 from the meter roller 510 . the metering apparatus 500 comprises the meter roller 510 , in this case a pegged meter roller although any suitable meter roller ( e . g . a smooth roller , fluted roller or high output roller ) may be employed , mounted on shaft 517 and disposed within the metering chamber 506 of a meterbox 507 . the metering chamber 506 is in communication with the hopper 550 via the inlet 515 so that the agricultural product 520 in the hopper 550 can flow into the metering chamber 506 . the agricultural product 520 collects on a floor 509 of the metering chamber 506 and engages with the meter roller 510 . as seen in fig5 e , when the meter roller 510 is in a lowered position , rotation of the meter roller 510 , in this case clockwise rotation , meters the agricultural product 520 at a regulated rate up and over a lip 512 proximate an end of an inclined portion 513 of the floor 509 of the meterbox 507 to exit the metering chamber 506 through an outlet 530 into the air distribution line , which carries the agricultural product 520 to product application outlets for distribution in a field . when it becomes desirable to cut off flow of the agricultural product 520 to the air distribution line , the meter roller 510 is raised as seen in fig5 a and fig5 b . the meter roller 510 may be raised by lifting the shaft 517 . because the meter roller 510 is now higher , the meter roller 510 cannot engage the agricultural product 520 resting on the floor 509 thereby stopping flow of agricultural product 520 over the lip 512 and stopping flow of agricultural product 520 into the outlet 530 . further , to ensure that the metering chamber 506 doesn &# 39 ; t simply fill up with agricultural product 520 to the level of the meter roller 510 when the meter roller 510 is in the raised position , an inlet guard plate 518 depending down from the hopper 550 into the metering chamber 506 is configured to be long enough that the end of the inlet guard plate 518 is at the level of or lower than the lip 512 . to bring the agricultural product 520 back into contact with the meter roller 510 , the meter roller 510 is lowered back into contact with the agricultural product 520 as depicted in fig5 e . with reference to fig6 a and fig6 b , two side - by - side metering apparatuses 600 a , 600 b are depicted each operating similarly to the metering apparatus depicted in fig5 a to fig5 f . both metering apparatuses 600 a , 600 b are housed in the same meterbox 607 . the metering apparatus 600 a comprises a roller housing that is shown housing meter roller 610 a in a raised , product disengaging position , while the metering apparatus 600 b comprises a roller housing that is shown housing meter roller 610 b in a lowered product engaging position . the housing that houses meter roller 610 a is raised and lowered by actuator 674 a , while the housing that houses meter roller 610 b is raised and lowered by actuator 674 b . the actuators 674 a and 674 b may be independently controlled so that one or the other or both meter rollers 610 a , 610 b may be metering or not metering agricultural product . the meter rollers 610 a , 610 b are constantly driven by the same drive axle 627 , whether in the raised or lowered positions . the meter rollers 610 a , 610 b are mounted on separate shafts ( not shown ) together with separate gears . gear 615 a for meter roller 610 a can be seen in fig6 a . the gears are intermeshed with sprockets 628 a , 628 b mounted on and driven by the drive axle 627 . the drive axle 627 drives the sprockets 628 a , 628 b , which in turn drive the gears and thus the meter rollers 610 a , 610 b . the drive axle 627 also provides an axis for the meter rollers 610 a , 610 b to pivot about when being raised and lowered by the actuators 674 a and 674 b . raising and lowering the meter rollers 610 a , 610 b does not disengage the gears from the sprockets so the meter rollers 610 a , 610 b are always driven , whether or not they are actively metering agricultural product . because the meter rollers 610 a , 610 b are mounted on separate shafts , servicing the meter rollers 610 a , 610 b , for example , cleaning or changing out the meter rollers , is facilitated as the meter rollers 610 a , 610 b may be accessed , and if needed individually removed , through access ports 621 a , 621 b . the structure and operation of the remainder of the metering apparatuses 600 a , 600 b are like that described in connection with fig5 a to fig5 f . the metering apparatuses 600 a , 600 b are shown in cooperation with air distribution lines 640 a , 640 b therebelow . the air distribution lines 640 a , 640 b are housed in an air distribution box 645 and each line 640 a , 640 b receives agricultural product metered by the metering apparatus directly thereabove . agricultural product metered into each line 640 a , 640 b is carried by a flow of air to product application outlets for distribution in a field . with reference to fig7 a , fig7 b and fig7 c , a metering apparatus 700 is shown in which flow of agricultural product from a hopper 750 to an air distribution line 751 may be stopped from entering the air distribution line 751 by moving , in this case lowering , the agricultural product in a metering chamber 706 away from a continuously turning meter roller 710 to disengage the agricultural product from the meter roller 710 . the metering apparatus 700 comprises the meter roller 710 , in this case a pegged meter roller although any suitable meter roller ( e . g . a smooth roller , fluted roller or high output roller ) may be employed , mounted on shaft 717 and disposed within the metering chamber 706 of a meterbox 707 . the metering chamber 706 is in communication with the hopper 750 via a tube 714 having an inlet 715 so that the agricultural product in the hopper 750 can flow through the tube 714 into the metering chamber 706 . the agricultural product collects on a floor 709 of the metering chamber 706 and engages with the meter roller 710 . as seen in fig7 b , when the floor 709 of the metering chamber 706 is in a raised position , rotation of the meter roller 710 , in this case counterclockwise rotation , meters the agricultural product at a regulated rate up and over a lip 712 proximate an end of an inclined portion 713 extending up from the floor 709 to exit the metering chamber 706 through an outlet 730 into the air distribution line 751 , which carries the agricultural product to product application outlets for distribution in a field . when it becomes desirable to cut off flow of the agricultural product to the air distribution line 751 , the floor 709 of the metering chamber 706 is lowered as seen in fig7 a and fig7 c . the meterbox 707 comprises a trough portion 701 , the trough portion 701 comprising the floor 709 , a back wall 702 and a ceiling portion 703 , the ceiling portion 703 secured to the tube 714 so that agricultural product may flow from the tube 714 into the metering chamber 706 through an aperture in the ceiling portion 703 . to lower the floor 709 , the trough portion 701 and the tube 714 to which the ceiling portion 703 of the trough portion 701 is secured , are linked to an actuator 727 ( e . g . a hydraulic cylinder or an electric actuator ) through a flange 728 secured to the back wall 702 of the trough portion 701 . the flange 728 is linked to a plunger 729 by a linkage pin 730 , and the plunger 729 is connected to an extendible rod 726 of the actuator 727 . extension of the rod 726 pushes the trough portion 701 and the tube 714 vertically downward to the lowered product disengaging position as seen in fig7 a and fig7 c , while retraction of the rod 726 pulls the trough portion 701 and the tube 714 vertically upward to the raised product engaging position as seen in fig7 b . a compression spring 731 seated around the plunger 729 is compressed when the rod 726 is extended thereby exerting a bias on the trough portion 701 and the tube 714 back toward the raised position . in case of a failure of the actuator 727 , the spring 731 ensures that the trough portion 701 and the tube 714 are in the raised position so that metering of agricultural product into the air distribution line 751 may continue . while the tube 714 is depicted as cylindrical , any suitable cross - sectional shape of tube may be employed , for example an elliptical or a polyhedral cross - section ( e . g . triangular , square , rectangular , pentagonal , hexagonal and the like ). a polyhedral cross - section provides a benefit of reducing a tendency of the tube to twist or move laterally while being raised and lowered . to further reduce the tendency of the tube 714 to move laterally while being raised and lowered , the tube 714 is bracketed by guides 734 and 735 , the tube 714 being allowed to move vertically freely within the guides 734 and 735 . the novel features of the present invention will become apparent to those of skill in the art upon examination of the detailed description of the invention . it should be understood , however , that the scope of the claims should not be limited by the preferred embodiments set forth in the examples , but should be given the broadest interpretation consistent with the specification as a whole .
a metering apparatus for distributing an agricultural product in a field has a meterbox configured for association with a hopper for receiving agricultural product from the hopper . a rotatable metering element is disposed within a chamber in the meterbox , and the rotating metering element is configured to deliver the agricultural product at a regulated rate from the hopper through the chamber to a product distribution line . delivery of the agricultural product to the product distribution line may be selectively stopped by a reversibly inflatable seal between the metering element and an outlet to the distribution line , a reversible seal formed by contact between the metering element and an inlet from the hopper to the chamber , or a disengagement structure for disengaging the agricultural product from the metering element while the metering element continues to rotate .