Measuring and dispensing system for solid dry flowable materials

A portable apparatus for measuring and dispensing solid dry flowable materials, comprising a hopper for containing material, a quantitative measuring device having a dispensing outlet, material inlet means in communication with said hopper and said quantitative measuring device for regulating the flow of material between, system control means in communication with quantitative measuring device for controlling type of measurement and quantity of material and a receptacle in communication with the dispensing outlet of said quantitative measuring device. The invention includes a method of measuring a solid dry flowable material comprising feeding the material into a quantitative measuring device having a screw, rotating the screw a specified number of turns dependent upon material type and quantity of material desired such that material is transported along the length of the screw to material outlet means while being measured and metered and passing the material through the material outlet means and directly into a receptacle.

FIELD OF THE INVENTION
 The present invention relates to a system for measuring and dispensing
 solid dry flowable materials. More particularly, the present invention
 relates to apparatus for measuring and dispensing solid dry flowable
 agricultural products.
 BACKGROUND OF THE INVENTION
 Apparatus and devices for handling granular chemicals have been developed
 for a variety of purposes. U.S. Pat. No. 5,029,624 discloses a closed
 granular chemical handling system comprising a dispensing valve and a
 receiving valve that are configured to operate in a desired sequence. U.S.
 Pat. No. 4,054,784 discloses a weigh feeder system including a device for
 controllably discharging a substance from a container and apparatus for
 weighing the container. WO95/10363 pertains to a metering device for dry
 direct injection into a spray tank. Dosieren zur
 Prozen.beta.automatisierung--Systematik, Materialflu.beta.,
 Dosiergenauigkeit, by G. Vetter, Wagen und Dosieren, vol. 23, no. 1,
 (1992) discloses dosing applications and various dosing methods. There
 exists a need for a portable apparatus to accurately measure and dispense
 solid flowable materials such as dry flowable (DF) materials especially in
 agriculture where hand held measuring devices are routinely used in field
 conditions.
 SUMMARY OF THE INVENTION
 A portable apparatus for measuring and dispensing solid dry flowable
 materials, comprising:
 a hopper for containing material;
 a quantitative measuring device having a dispensing outlet;
 material inlet means in communication with said hopper and said
 quantitative measuring device for regulating the flow of material
 therebetween;
 system control means in communication with quantitative measuring device
 for controlling type of measurement and quantity of material; and
 a receptacle in communication with the dispensing outlet of said
 quantitative measuring device.
 The present invention also includes a method of measuring a solid dry
 flowable material comprising feeding the material into a quantitative
 measuring device having a screw, rotating the screw a specified number of
 turns dependent upon material type and quantity of material desired such
 that material is transported along the length of the screw to a material
 outlet means while being measured, metered and reduced in particle size,
 and passing the material through the material outlet means and directly
 into a receptacle.

DETAILED DESCRIPTION OF THE INVENTION
 It is an object of the present invention to provide a portable system for
 accurate measuring and dispensing of solid dry flowable materials. Solid
 dry flowable materials of this invention are powders, granules, or in
 general, solid materials which are flowable. Typical solid dry flowables
 can be, but are not limited to, agricultural products, pharmaceuticals,
 inorganic or organic pigments, plastics, cosmetics, foods like dehydrated
 dairy products, animal feeds and the like. Product specific refers to a
 single product. This invention is especially useful for providing a
 portable means to transfer low use rate agricultural products in a way
 that minimizes spillage, accurately measures and dispenses a specific
 product, provides minimum operator exposure to the product dispensed,
 improves recordkeeping, labeling and inventory control.
 SYSTEM DESCRIPTION
 This invention can be more fully understood from the following detailed
 description of the invention. Having reference to FIGS. 1, 2 and 3, there
 is shown a system useful for measuring and dispensing solid dry flowable
 materials.
 The measuring and dispensing system comprises a weather proof, lockable
 cabinet within which is mounted housing (12). Within lockable cabinet (10)
 is on/off power strip (14) which controls electrical power to the system.
 Housing (12) contains the operating components of the system. Mounted in
 the upper portion of housing (12) is hopper (16) having inlet opening (18)
 and outlet opening (20). Hopper (16) is capable of containing a suitable
 amount of solid, dry flowable material and can be connected to and
 operated in cooperation with material inlet means (22). Hopper (16) is
 preferably made of a material that is resistant to corrosion and that has
 a relatively low coefficient of friction. In a preferred embodiment, the
 hopper can be sealed substantially air-tight. Normally hopper (16) will be
 mounted on top of, i.e., above, quantitative measuring device (26) of the
 present invention, and the material will be gravity fed to the material
 inlet means. Alternative means for introducing material to material inlet
 means (22) and sealing the apparatus can be used without departing from
 the present invention.
 Attached to the bottom of hopper (16) surrounding outlet opening (20) is
 material inlet means (22) shown here as an electronic shutoff valve but
 which can be a manual shutoff valve. Material inlet means (22) allows the
 material to flow out of hopper (16) and into quantitative measuring device
 (26). Material inlet means (22) is shown here equipped with interlock
 sensor (24) which ensures that material inlet means (22) is in the open
 position before dispense of material is initiated from hopper (16).
 Mounted in housing (12) is quantitative measuring device (26) to receive
 receptacle (32) and ensure proper alignment under material outlet means
 (22). The components of quantitative measuring device (26) are optionally
 mounted on a frame support (50) and device housing (52) for convenient
 access. The quantitative measuring device (26) can comprise an
 exchangeable module. One embodiment of quantitative measuring device (26)
 can measure the weight of material being dispensed into receptacle (26).
 Another embodiment of quantitative measuring device can measure the volume
 of material being dispensed into receptacle (32) and is dependent upon the
 bulk density of the material. An example of quantitative measuring device
 (26) for weight measurement is a 10K loadcell #MS4010 from measurement
 specialists of Palm Bay, Fla. Those skilled in the art will readily
 appreciate that other devices may be used.
 Description of Volumetric Measuring Device
 An example of quantitative measuring device (26) for volumetric measurement
 can be found in the PCT publication WO95/10363 and is depicted in a
 schematic side view in FIG. 4 herein.
 Longitudinal screw housing (40) having a cylindrical cavity has positioned
 within it screw (42) having flights designed to measure, transport and
 reduce the size of the solid dry flowable material that enters screw
 housing (40) by means of material inlet means (22) which is adjacent to
 screw (42) at one end of screw housing (40) and exits screw housing (40)
 and enters receptacle (32) at the other end through dispensing outlet (28)
 and material outlet means (30).
 Material inlet means (22) connects hopper (16) to screw housing (40) and
 admits material to a first portion of screw (42). Material inlet means
 includes a port in screw housing (40) which is suitably at least the width
 of 1 flight and preferably at least 1.5 flights so that composition is
 preferably being feed to more than one screw-flight. The port is also of a
 dimension and location such that preferably the particulate composition is
 always fed to a constant-depth portion of screw described hereinafter even
 when the longitudinal position of screw (42) is adjusted within screw
 housing (40), as described hereinafter.
 Means (56) for adjusting the longitudinal position of screw (42) within
 screw housing (40) adjusts the position of the screw flights relative to
 material inlet means (22) and material outlet means (30) which are in
 fixed position on screw housing (40).
 The amount of adjustment is limited so that material inlet means (22) will
 always feed to a constant-depth portion of screw flight.
 Means (34) for rotating screw (42) relative to screw housing (40) shown
 here as drive motor (34) is preferably adjustable by system control means
 (36) so that rpm of screw (42) can be varied, and once adjusted it must
 hold constant so that a steady amount of material is transported from
 inlet to outlet and into receptacle (32). Suitable means (34) includes a
 variable speed motor coupled to the screw shaft such that the motor has
 sufficient power to turn the screw at suitable rpm. Coupling of rotating
 means (34) to the shaft must be able to accommodate the longitudinal
 adjustment of screw (42).
 Screw (42) is mounted within housing such that the ends of screw (42) or a
 shaft that is supporting screw (42) form a seal with the respective ends
 of screw housing (42) such that if material inlet means (22) and material
 outlet means (30) are also sealed, none of the material that may enter the
 cavity will be able to exit the cavity other than through material outlet
 means (30). Close tolerances between the shaft ends and the respective
 portions of screw housing (40) can provide a seal to prevent passage of
 any material other than through material outlet means (30). Preferably
 there are additional seals (58) at each end of screw housing (40); such
 seals (58) include standard lip seals (single, double or triple) or
 pressure sealing rings. Preferred are lip seals.
 The constant depth portion of screw (42) is at the inlet end of screw (42),
 and flights with a tapered shaft become increasingly more shallow toward
 the outlet end.
 The constant-depth flights are preferably at least as deep as the diameter
 of the largest particle of the material, and preferably at least three
 times as wide as the diameter of the largest particle. The threads on
 screw (42) which form the flights can be any one of various shapes
 including triangular, square, rectangular, rounded or trapezoidal.
 Rectangular threads are preferred. The longitudinal distance between the
 center of the threads parallel to the screw axis is known as the pitch.
 Feed rate will be determined by the pitch, the depth of the threads, the
 slope of the threads, the shape of the threads and the speed at which the
 screw is rotated. The pitch chosen for screws useful in the apparatus of
 the present invention will preferably be from 0.1 to 3 per centimeter. A
 pitch of about 1 thread per centimeter is generally preferred for
 agricultural compositions in which the active ingredient is a sulfonylurea
 or materials of similar potency, which are generally applied at rates of
 ounces per acre. Of course, if less potent, larger volume compositions are
 used, a larger screw with a different screw configuration will be used to
 get the appropriate feed rate.
 The shaft supporting screw (42) contains at least one groove (60) around
 the circumference of the shaft at a location on the shaft between the last
 screw flight at the outlet end of screw (42) and the seal formed between
 the outlet end of the shaft of the screw and the outlet end of screw
 housing (40), with the at least one groove (60) positioned on the shaft at
 a location adjacent to material outlet means (30). Groove (60) around the
 circumference of the shaft at a position on shaft between the last screw
 flight at the outlet end and the seal formed between the outlet end of the
 screw shaft and the outlet end of the housing helps prevent the exiting
 particulate composition from being forced into the outlet end seal (58)
 instead of dropping freely through the outlet into receptacle (32). Groove
 (60) is connected to the last flight, is at least as deep and wide as the
 last flight, and is smooth so as to avoid any points where solid
 composition might collect. Preferably groove (60) is deeper and wider than
 the last flight.
 Screw housing (40) and screw (42) can be made of any hard, wear-resistant
 material. Preferably screw housing is stainless steel and the screw is
 stainless steel or hardcoat anodized aluminum. Other parts of the present
 apparatus can be made of stainless steel, plastic, plexiglass, wood or
 other non-rusting, non-corroding sturdy materials.
 SYSTEM OPERATION
 The system is first calibrated to ensure that an accuarate quantity of
 material is metered each time. In the operation of the apparatus of the
 present invention, the material is loaded in the hopper and the hopper is
 preferably sealed. When the quantitative measuring device is activated,
 the material passes from the hopper, through material inlet means, into
 the quantitative measuring device and is forced toward the material outlet
 means. For volumetric measurements by the quantitative measuring device,
 adjustments to the number of turns of the screw controls the amount of
 material dispensed. For weight measurements by the quantitative measuring
 device, weight measurement controls the amount of material dispensed.
 A user will enter an amount of product required (or alternatively, a rate
 and number of acres) on a weather proof keyboard and the device will meter
 the required the amount of product into receptacle (32). To dispense
 product, receptacle (32) is placed under dispensing outlet (28) or
 material outlet means (30), if present, and material inlet means (22) is
 opened. The desired amount is entered into system control means (36) using
 the numeric key pad (44). The dispense cycle is initiated by pressing a
 start button ( ) which activates the quantitative measuring device (26)
 through system control means (36). Once the desired amount has been
 dispensed quantitative measuring device (26) shuts off automatically.
 System control means (36) at material outlet means (22) is closed and
 receptacle (32) is removed.
 To operate the system, product is loaded into hopper (16) and the operator
 first turns on the system using the electrical on/off switch located on
 power strip (14). Upon power up, the system control means (36) displays a
 request for a 4 digit Personal Identification Number (PIN). This number,
 which has been previously programmed into the system, controls access to
 the dispensing cycle of the system. Once the operator's PIN number has
 been entered using the numeric keypad (44), and accepted the display
 advances to the main operating screen. This screen provides access to the
 dispensing routine, a display of current hopper inventory and the update
 inventory routine. The update inventory routine is used when product is
 added to hopper (16). Access to update inventory routine is protected by a
 second 4 digit PIN which can be different from the power up PIN and
 controls who has access to inventory updating. When the dispensing routine
 is selected, a "Job Number" is requested. This "Job Number", which is
 entered by the operator, provides unique identification for each batch
 dispensed. Once the "Job Number" has been entered, the display prompts the
 operator to place an empty receptacle (32) on or beneath quantitative
 measuring device (26). The screen then displays the quantity requested and
 prompts the operator to press the "start" button to open material outlet
 means (30) and begin the actual dispense. Product is then dispensed into
 receptacle (32) until the targeted amount minus a preset quantity is
 reached. The system then goes into a dribble routine which dispenses very
 small individual batches of product into receptacle (32) until the exact
 targeted amount is reached.
 The quantitative measuring and dispensing apparatus of this invention
 provides a convenient way to accurately measure and dispense solid dry
 flowable materials; in the case of agricultural materials the quantitative
 measuring and dispensing apparatus allows last minute changes to acreage
 or changes in product use rate; keeps records of product use and
 inventory; helps address worker exposure issues since the transfer of the
 product can be done in a closed system. The field measuring and dispensing
 apparatus of this invention provides better accuracy (+/-2%) compared to
 hand-held measuring guide (+/-7%). The field measuring and dispensing
 apparatus of this invention is portable and can be mounted on a sprayer,
 in the bed of a pickup truck, or on a nurse tank trailer or truck or any
 similar vehicle and has been developed to accurately measure water
 dispersible granules under field conditions where it can operate on
 readily available 12 volt power. The field measuring and dispensing
 apparatus allows the operator to measure material at the point of use so
 that last minute changes to acreage or product use rate can be easily and
 accurately implemented. Field calibrations can accommodate changes in
 product bulk density. The apparatus is electronically controlled and can
 meter dry flowable materials in amounts ranging from about 15 grams to
 several kilograms accurately.
 In the above recitations, the term operator means anyone who uses the
 system of this invention and in the case of an agricultural product can
 mean a dealer, or an applicator.
 It is understood that the above described embodiments are meant to be
 illustrative of the principles of this invention and not all possible
 embodiments of this invention.