Grain processing apparatus

Abstract: An apparatus and method for processing grain by raising the moisture content of the grain relative to a target level. As the grain is moved through a processing area, the moisture content (27) and the mass flow of the grain (29) are measured. Each measurement is converted to an electronic signal and the signals are fed to a programmable controller (33) which blends the two signals and produces a single output control signal that is fed to a proportional control valve (35). The control valve (35) acts responsive to the control signal to adjust the amount of moisture added to the grain at a wetting station (39). An additive (43) such as a surfactant can be metered into the water supply.

Description: The present invention is an apparatus and method for processing grain by raising the moisture content of the grain to a target level. Grain processing facilities, such as a commercial livestock feed mill, typically have a central processing area and several bulk grain storage bins. Grain flows from these bins into the processing area either by gravity or through augers that draw grain from the bottoms of the bulk bins. In either case, the flow rate of the grain from the various sources is quite variable. It is not uncommon for there to be as much as 100 percent variation between the highest and lowest grain flow rates within a particular facility. The first automated grain conditioning apparatus was designed to monitor and adjust the moisture content of a single grain entering a processing area, where the flow rate of the grain was assumed to be relatively constant. When more than one grain flow rate was encountered, various manual adjustments were made to control the signal to produce the desired result. This approach worked, but was entirely empirical, and produced a less then fully automated system. The apparatus had a capability to adjust the amount of moisture added to the incoming grain only according to changes in the moisture content of the grain. The apparatus had no capability to track and adjust for any changes in the mass flow rate. If an individual grain source changed flow rate after the initial calibration, or if there were variations in grain flow during operation, there was no automatic adjustment of the amount of moisture being added. U.S. Patent No. 4,993,316 discloses an apparatus for applying moisture to seed grain that automatically and precisely applies sufficient moisture to the seed grain to bring it to a target moisture content sufficient for germination. The apparatus includes: a hopper for holding a supply of seed grain; a conveyor for moving the seed grain from an outlet of the hopper to a discharge location; a sensing station and a wetting station on the conveyor between the hopper outlet and the discharge location, the wetting station being located downstream of the sensing station; a moisture sensor, positioned at the sensing station, to measure the moisture content of a sample of the passing seed grain and to convert the measurement into an electronic signal; a liquid applicator at the wetting station to disburse liquid upon passing seed grain; and a controller to regulate the rate of moisture addition to the seed grain according to the electric signal generated by the moisture sensor. The object of the present invention is to provide an apparatus and method which overcome the foregoing problems. The present invention provides a grain processing apparatus for moisturizing grain to an approximate target moisture content through the controlled addition of moisture derived at least in part from a water supply, as the grain moves in a downstream direction through a grain processing area from a first location toward a second location, comprising electrically operated grain conveying means for moving grain in said downstream direction to and through the grain processing area, having a sensing station and a wetting station located downstream of the sensing station; a moisture sensor at the sensing station located to intercept a sample of passing grain for substantially continuous measurement of the moisture content of the sample and translation of the measurement into a first electronic signal; liquid applicator means at the wetting station to disburse liquid derived at least in part from a water supply upon passing grain; a liquid supply line connected to the liquid applicator means for connection to the water supply; a proportional flow control valve located in the liquid supply line having an electronically actuated valve control movable between an open and a closed position to regulate the amount of liquid flow to the liquid applicator means for application to passing grain; programmable controller for receiving the first electronic signal and providing an output control signal; means connecting the programmable controller to the proportional flow control valve so that the valve control operates responsive to the output control signal according to the difference between the moisture content of the grain sample and the target moisture content; characterized by an electric current sensor associated with the grain conveying means to continuously measure the electric current drawn by the grain conveying means and convert the measurement into a second electronic signal; means connecting the moisture sensor and electric current sensor to the programmable controller for receipt of the first and second electronic signals; and programmable controller having means for blending the first and second electronic signals and creating a resultant output control signal. The present invention also provides a method of processing grain as it is moved through a grain processing area from an upstream location along a path toward a downstream location, through regulated addition of moisture derived at least in part from a water supply, in order to regulate the moisture content of the grain relative to an approximate target moisture content, comprising providing a moisture sensor specifically calibrated to measure moisture content of the type of grain to be conditioned and adapted to generate a first electronic signal proportional to the moisture content; moving the grain on electrically operated conveying means; measuring the moisture content of a sample of the moving grain at a first station on the path of travel of the grain, using the moisture sensor to substantially continuously monitor the moisture content of moving grain and translate the measurement into a substantially continuously generated first electronic signal; providing a programmable controller, providing liquid to the liquid applicator apparatus through a liquid line extended from a water supply; providing a proportional flow control valve in the liquid line of the type having an electronic valve control for regulating the opening and closing of the valve to regulate water flow through the valve by an electronic signal; and controlling the valve control of the automatic valve with the output control signal generated by the programmable controller to modulate the flow of water to the liquid applicator apparatus, characterized by providing an electric current sensor to measure the electric current drawn by the grain conveying means adapted to generate a second electronic signal proportioned to the mass flow of the grain; and measuring the mass flow of the grain using the electric current sensor to continuously measure the electric current drawn by the grain conveying means and translate the measurement into a substantially continuously generated second electronic signal; connecting the second electronic sensor to the programmable controller for receipt of the second electronic signal and blending the first and second electronic signals to produce said output control signal. In the drawings: Figure 1 is a schematic view of the grain processing apparatus of the invention partially fragmented for purposes of illustration; and Figure 2 is a schematic of an alternative control system for the apparatus of Figure 1. Referring to the drawings, there is shown in Figure 1 a grain processing apparatus according to the invention indicated generally at 10 positioned to intercept a flowing grain 11 for the purpose of conditioning it through the addition of liquid comprised of either water alone or water mixed with an additive such as a nutrient, a surfactant or a flavoring agent. A purpose of adding the liquid to the grain is to bring the grain up to a uniform target moisture content. For example, it is desirable to bring feed grain up to a target moisture content to enhance the digestibility of the feed to the animal as expressed with respect to the apparatus shown in US-A,4,898,092. By way of further example, seed grain requires moisture for germination, preferably water mixed with a surfactant to enhance moisture penetration of the grain. It is desirable to bring the seed grain to a target moisture level only, as excess moisture will be wasteful of the surfactant as expressed with respect to the apparatus shown in US-A-4,993,316. Grain as introduced to the apparatus 10 will be of varying moisture content. The grain that has been in storage will have a relatively low moisture content, while grain more recently harvested will usually have a somewhat higher moisture content. The grain conditioning apparatus 10 continuously senses and monitors the moisture content of the incoming grain and adjusts the amount of liquid added as required to bring the moisture content to the target level. Another purpose of adding liquid to grain is the use of water as a solvent or carrier for an additive such as a flavor enhancer or mold inhibitor. Excessive addition of water can accelerate spoilage. In this situation the target moisture level effectively becomes an upper limit which can be approached but not exceeded. Not only will the initial moisture content of grain 11 vary greatly, but the mass flow rate of grain introduced to the processing area will also vary. Grain 11 can be transported from a location of origin such as a storage bin, an elevator or a grain truck, so as to be traveling usually in a downstream direction of travel but at different mass flow rates according to location of origin. Grain processing apparatus 10 includes grain conveyor means for moving the grain 11 in a downstream direction form an input location to a discharge location and comprising an auger assembly 14. Auger assembly 14 includes an auger housing 15 with a centrally located auger shaft 16. A helical auger flight 17 surrounds the auger shaft 16. An inlet chute 19 admits the grain at the upstream end of auger housing 15. An outlet chute 20 is located at the opposite end for discharge of processed grain. The upstream end 21 of auger shaft 16 extends outwardly of the auger housing 15 and is connected to an electric motor 23. Electric motor 23 has an electric wire power cord 24 connected to an alternating current power source 25. A capacitance type moisture sensor 27 is installed at a moisture sensing station in the auger housing 15 with a portion thereof extended into the interior of the auger in the path of traveling grain so as to be able to intercept a sample of the passing grain and continuously measure the moisture content thereof. Moisture sensor 27 is calibrated according to the type of grain being conditioned. The auger flight 17 is truncated as at 28 in order to provide clearance for the moisture sensor 27 in the interior of auger housing 15. Moisture sensor 27 provides a first control signal for control of application of liquid to the passing grain. While moisture sensor 27 is shown located in the auger housing 15, it could be located elsewhere wherever it might be able to continuously sample a portion of passing grain for measurement of the moisture thereof. Moisture sensor 27 can be of the variety disclosed in US-A-4,898,092. A calibrated electric current load sensing device 29 is associated with the motor 23 to sense the amount of work being done by the motor 23. Load sensing device 29 can be connected in the power cord 24 of motor 23 in the fashion of a conventional ammeter or galvanometer. In one preferred embodiment, the electric load sensing device 29 includes a torus shaped sensor having cord 24 passing centrally through it so as to measure the strength of the electromagnetic field generated by the current flowing through the wire. The purpose of load sensing device 29 is to measure the mass flow of the grain passing through auger housing 15. The load sensing device 29 produces a mass flow signal by measuring the electric current being drawn under load by the motor 23. The motor 23 has a baseline current draw, meaning the electrical current required to operate the conveying device empty. As the mass flow of grain through the conveyor increases, the electric current (amperes) needed to run the motor also increases proportionally. The electric load sensing device 29 produces a second control signal for controlling the amount of liquid to be applied to the grain. While the control device 29 is shown also with respect to the auger motor 23, it could as well be associated with other motors characteristically encountered in the grain processing industry and used for conveying the grain through the processing apparatus such as a grain elevator, a mixing auger, a pit auger, a bin auger or the like. The output signal of the moisture sensor 27 is carried through the moisture sensor control signal line 31. The output signal of the load sensing device 29 is carried through the load device signal line 32. Both of these lines lead to an electronic control module 33 where a programmable controlling device blends, or proportions the first and second signals according to a predetermined ratio to produce a third resultant signal. This third resultant or control signal is used to position a proportional flow control valve 35 through an output signal line 36. Means for introduction of a liquid mixture to the grain includes a spray nozzle 37 for delivering a spray product 39 to the grain in auger housing 15. Spray nozzle 37 is mounted on auger housing 15 and communicates with the interior thereof at a wetting station located downstream of the sensing station. Spray nozzle 37 is connected to one end of and derives liquid product from a liquid product supply line 40. The opposite end of liquid supply line 40 is connected to the output side of the proportional flow control valve 35 which supplies water in regulated amounts to the liquid line 40. The input side of proportional flow control valve is connected to a water supply line 41. Water supply line 41 is connected to source of water under pressure as from a community water source or the like (not shown). Liquid additive such as a surfactant is contained in a supply container 43 which rests on a commercial scale 44 for purposes of determining depletion thereof. An additive pump 45 is connected to the container 43 and derives additive from it for pumping through an additive supply line 47 which is connected to the liquid line 40. An additive pump control signal line 48 connects the additive pump 45 to the output line of the electronic control module 33. In use, as grain flows into the mixing auger 14, the moisture sensor 27 generates a first electronic signal proportional to the moisture content of the grain. As the auger fills, more energy is required to turn the auger shaft than when the auger was empty. The current or load sensing device 29 generates a second electronic signal proportional to the mass flow of the grain. The load sensing device could also be used with the motor of another characteristic conveyance means feeding grain into the mixing auger, such as an elevator (leg), pit auger feeding the elevator or a bin auger moving grain from a storage bin into the process stream. Locating the load sensor on the mixing auger is generally preferred because of its immediacy to the point of treatment. The moisture sensor is positioned to intercept a representative sample of the grain entering the processing stream. Other sensor designs and geometries available make it possible to intercept the grain sample in a variety of locations such as the spout bringing the grain to the mixing auger, or immediately below a grain cleaner or scalper, or at the top or bottom of an elevator. The moisture and load output signals are fed into the electronic control module 33 where the programmable controlling device blends, or proportions the signals according to a predetermined ratio to provide the signal at the output line 36 that is used to position the proportional flow control valve. This signal also is used to control the additive pump 45 in order to meter the amount of additive being added to the liquid line 40 according to the amount of water flowing through the proportional control valve 35. An amount of resultant fluid is added to the grain regulated according to the moisture content of the grain and the mass flow of the grain. This fluid is throughly mixed with the grain through the action of the mixing auger. In another configuration, there is provided a water flow meter 50 located in the liquid line 40 and having a water flow meter output signal line 51 connected to the electronic control module 33. Water flow meter device 50 is used in the event that the water pressure at the water input line 41 is variable whereby the output at the proportional flow control valve 35 at a given control signal would vary with fluxuating water pressure. The water meter 50 provides a signal indicative of the liquid flow through the pipe 40. The blended output signal at the electronic output line 36 is used as a target and the proportional, flow control valve position is adjusted by the controller until the signal received from the water flow meter matches the proportioned signal. If desired, in order to insure that the additive supplied to the liquid pipe 40 is proportionate to the supply of water, the additive pump can be controlled by the water meter 50. This is indicated by the phantom additive pump signal line 53 in Figure 1. Figure 2 depicts a scheme wherein the amount of additive supplied to the grain is proportioned to the mass flow. The load sensor 29 and moisture sensor 27 provide control signals through the respective control signal lines 32, 33 which are blended at the programmable controlling device 33 providing a result in control signal 36 which positions the proportional control valve 35. A load sensor signal line 54 provides the load sensor signal alone for control of the additive pump 45. The amount of additive will be regulated by mass flow of grain alone independent of the moisture content. This scheme is useful for the addition of substances requiring addition rates based on the total mass of grain processed and not moisture content, such as for the addition of mold inhibitors and micro-nutrients.

Claims: A grain processing apparatus for moisturizing grain to an approximate target moisture content through the controlled addition of moisture derived at least in part from a water supply, as the grain moves in a downstream direction through a grain processing area from a first location toward a second location, comprising electrically operated grain conveying means (14) for moving grain in said downstream direction to and through the grain processing area, having a sensing station and a wetting station located downstream of the sensing station; a moisture sensor (27) at the sensing station located to intercept a sample of passing grain for substantially continuous measurement of the moisture content of the sample and translation of the measurement into a first electronic signal; liquid applicator means (37) at the wetting station to disburse liquid derived at least in part from a water supply upon passing grain; a liquid supply line (41) connected to the liquid applicator means for connection to the water supply; a proportional flow control valve (35) located in the liquid supply line having an electronically actuated valve control movable between an open and a closed position to regulate the amount of liquid flow to the liquid applicator means for application to passing grain; programmable controller (33) for receiving the first electronic signal and providing an output control signal; means connecting the programmable controller to the proportional flow control valve (35) so that the valve control operates responsive to the output control signal according to the difference between the moisture content of the grain sample and the target moisture content; characterized by an electric current sensor (29) associated with the grain conveying means to continuously measure the electric current drawn by the grain conveying means and convert the measurement into a second electronic signal; means (31,32) connecting the moisture sensor (27) and electric current sensor (29) to the programmable controller for receipt of the first and second electronic signals; and programmable controller (33) having means for blending the first and second electronic signals and creating a resultant output control signal. The grain processing apparatus of Claim 1, characterized in that said grain conveying means includes a mixing auger (17) and electric motor (23) to drive the auger. The grain processing apparatus of Claim 2, characterized in that said electric current sensor (29) is associated with a power cord to the auger motor (23) to sense electric loading on the auger motor proportionate to mass flow of grain being conveyed. The grain processing apparatus of Claim 3, characterized by a supply means (43) to supply liquid additive for mixture with the water for application to the grain and means (47) connecting the additive supply means to the liquid supply line for mixture of additive and water preparatory to application to the grain. The grain processing apparatus of Claim 4, characterized in that said additive supply means includes an additive supply container (43), and additive pump (45) connected to the additive supply container, and an additive supply line (47) connected between the additive pump and the liquid supply line to supply additive in regulated amounts to the liquid supply line for mixing with the water preparatory to application to the grain. The grain processing apparatus of Claim 5, characterized by means (48) connecting the additive pump (45) to the programmable controller (33) so that supply of additive is controlled by the output signal. The grain processing apparatus of Claim 5, characterized by means (54) connecting the additive pump (45) to the electronic load sensor (29) so that the supply of additive is controlled by the second electronic signal. The grain processing apparatus of any of claims 1 to 7, characterized by a water flow meter (50) located in the liquid supply line (41) to measure the flow of liquid and produce an electronic signal proportionate to the flow of liquid; said programmable controller (33) having means for blending the first and second electronic signals and creating a resultant output control signal, and means for comparing the resultant output signal with the electronic signal from the water flow meter; and means (51) connecting the programmable controller (33) to the proportional control valve (50) so that the valve control is operated responsive to the comparison between the output control signal and the water flow meter signal. The grain processing apparatus of Claim 8, characterized by means (53) connecting the additive pump to the water flow meter (50) so that the supply of additive is controlled according to the liquid flow in the liquid supply line (41). A method of processing grain as it is moved through a grain processing area from an upstream location along a path toward a downstream location, through regulated addition of moisture derived at least in part from a water supply, in order to regulate the moisture content of the grain relative to an approximate target moisture content, comprising providing a moisture sensor specifically calibrated to measure moisture content of the type of grain to be conditioned and adapted to generate a first electronic signal proportional to the moisture content; moving the grain on electrically operated conveying means; measuring the moisture content of a sample of the moving grain at a first station on the path of travel of the grain, using the moisture sensor to substantially continuously monitor the moisture content of moving grain and translate the measurement into a substantially continuously generated first electronic signal; providing a programmable controller, providing liquid to the liquid applicator apparatus through a liquid line extended from a water supply; providing a proportional flow control valve in the liquid line of the type having an electronic valve control for regulating the opening and closing of the valve to regulate water flow through the valve by an electronic signal; and controlling the valve control of the automatic valve with the output control signal generated by the programmable controller to modulate the flow of water to the liquid applicator apparatus, characterized by providing an electric current sensor to measure the electric current drawn by the grain conveying means adapted to generate a second electronic signal proportioned to the mass flow of the grain; and measuring the mass flow of the grain using the electric current sensor to continuously measure the electric current drawn by the grain conveying means and translate the measurement into a substantially continuously generated second electronic signal; connecting the second electronic sensor to the programmable controller for receipt of the second electronic signal and blending the first and second electronic signals to produce said output control signal.

Inventors: GREER DAVID G, GREER, DAVID G.
Applicants: AGRICHEM INC, AGRICHEM, INC.
Application year: 1992
Main classification: B02B1
IPC codes: B02B1