WO2003056944A1 - Method of converting mixing apparatus to automatically coat granular products - Google Patents

Abstract

A method of converting a mixing apparatus to automatically coat granular material fed from a suply (6) thereof to a weighing station (20) via a supply duct (8a) with an auger therein driven by a motor (9). Spray nozzles (19a) are positioned around outlet (10) which coat the feed as it falls under gravity into bucket (21). Control means (30) ensure that the coating additive is only sprayed onto granular material leaving outlet (10).

Description

Method of Converting Mixing Apparatus to Automatically Coat Granular Products

This invention relates to a method of converting a known mixing apparatus which mixes an additive with granular products so that it can be used to coat said material automatically with the additive.

In the commercial rearing of broiler chickens, it is common practice to mix whole-wheat grain to manufactured feed compound on site to make savings on broiler ration costs. However, the lower nutritional value of the whole-wheat when compared to the feed compound limits the amount that can be added to the feed compound so the potential to take full advantage of feed-cost savings is limited.

In a broiler house, each bird has its own preference for wheat or compound feed. This can lead to different growth rates and therefore variations in bird weights due to the nutrient gap between the whole-wheat and compound feed. The higher the proportion of wheat supplied to the birds, the greater the problem. This problem can be overcome by mixing an additive with the whole- wheat grain before feeding to close the nutrient gap. One form of additive is a liquid blend of amino acids - lysine and methionine, enzymes such as Avizyme (Trade Mark), soya oil and molasses products. Mixing this additive adds amino acids to the whole-wheat grain thereby bringing its nutrient value closer to that of a manufactured compound feed as the additive boosts lysine intakes and thus narrows the nutrient gap between the whole-wheat and manufactured feed. The inclusion of the feed enzyme Avizyme increases the availability of energy and protein in the added wheat thereby helping to improve the food conversion ratio (i.e. the number of kilos of feed to be eaten by a bird to put on 1 kilo of weight) and live weight gain. By narrowing the nutrient gap between the whole-wheat and manufactured feeds, the level of the added wheat can be increased thereby making bigger savings in feed costs. A major problem with known apparatus used to mix an additive with the wholewheat is that it is pumped from a supply thereof and mixed with the whole-wheat while it is being conveyed to a weighing station by a powered auger located in a supply duct. The additive is poured into the supply duct before it reaches the weighing station and is mixed with the whole-wheat by the action of the auger as it is conveyed along the supply duct. However, because the additive has a high content of molasses and due to the location where it is introduced into the whole-wheat, there is a tendency for the additive to bind with the chaff and wheat dust in the supply duct and coagulate. This can cause the auger to progressively slow down until it finally stops. In some cases, the motor which drives the auger can burn out or, in extreme cases, the supply pipe can even explode due to the build up of pressure therein. Once the auger has stopped, repairs can take some time to carry out and it is not uncommon for the feed apparatus to be "down" for between 4 and 6 hours while it is repaired. This down time will have a dramatic effect on the eventual weight of the birds in the broiler house when they come to be killed particularly if there have been several down times during the period up to slaughter which is not uncommon.

It is an object of the invention therefore to provide a method of converting known prior art mixing apparatus to operate in a manner which will overcome or substantially reduce these problems.

According to the invention, there is provided a method of converting an apparatus for mixing additive with granular material fed from a supply thereof to a weighing station, the apparatus including feed means for feeding the granular material to an outlet at the weighing station and a pump for supplying liquid additive to the granular material as it is fed to the weighing station, the method being characterised by mounting sensing means on the apparatus to sense when material is exiting said outlet, positioning spray means to coat the granular material as said material falls under gravity from the outlet into the weighing station and control means for controlling the pump and spray means so that coating liquid is only sprayed onto the granular material while said material is exiting said outlet. Compressed air may be added to the additive before it is sprayed onto the granular material.

Preferably the coating liquid is stored in a container and the pump is mounted on the top of said container.

Conveniently the spray means are positioned around the outlet for the granular material where said material falls under gravity into the weighing station.

Preferably the feed means is an auger driven by a motor and the sensing means senses when said motor is running.

Preferably the control means includes means to convert a 240 volt single phase power supply thereto into a three phase supply for the pump.

Although the invention is particularly concerned with the automatic coating of granular feed material supplied to broiler houses, it could be used in other applications such as the disinfecting of products or dosing of medicinal products.

The invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is an illustration of a prior art apparatus; Figure 2 shows a preferred method of the invention;

Figure 3 shows in more detail a preferred delivery system for spraying additive onto the product processed by the apparatus shown in Figure 2; and Figure 4 is the control system for the delivery system shown in Figures 2 and 3.

The apparatus shown in Figure 1 consists of a first hopper 1 for manufactured feed compound which is supported above the ground on legs 2 and having an outlet 3 in its base. A supply pipe 3a is connected to the base of the hopper and extends into the upper region of a weighing station 20 where it terminates in a vertical down-pipe section 5. There is also provided a second hopper 6 for whole-wheat, which is supported above the ground on legs 7 and has an outlet 8 in its base. A supply pipe 8a is connected to the outlet 8 in the base of the hopper and extends into the upper region of the weighing station 20 where it terminates in a vertical down-pipe section 10. Both ends 5 and 10 of the supply pipes 3a, 8a are positioned above the open top of a weighing bucket 21 which forms part of a weighing device (not shown). The weighing bucket 21 is positioned above a third hopper 23 which has an outlet 24 in its base connected to a pipe 24a which runs to a feed building 25 wherein it is connected to a feeder pipe 26. Down-pipes 27a,b,c connect the feed pipe 26 to feed trays 28a,b,c respectively. A flexible centreless auger 3B,8B is mounted in the supply pipes 3a, 8a powered by motors 4 and 9 respectively. A container 11 for liquid additive is connected to a pump 13 by a pipe 12, a pipe 14 joining the supply pipe 8a for the second hopper 6 at 15.

The motors 4, 9 drive the augers 3B,8B within supply pipes 3a, 8a to convey material from the hoppers 1 ,6 into the weighing station 20, where it drops from the down-pipe sections 5, 10 under gravity into the weighing bucket 21. The pump 13 pumps liquid from the container 11 along pipe 14 and into the supply pipe 8a at 15 wherein it mixes with the material from the hopper 6 being conveyed by the auger 8B. The material from the hoppers 1 , 6, together with the additive from the container 1 1 continue to fill bucket 21 until the weighing device (not shown) detects that the required pre-determined weight of material has been reached at which time motors 4, 9 are switched off so that the augers 3B,8B in the feed pipes 3a, 8a stop and no further material exits from the ends 5 and 10 of the supply pipes 3a, 8a. Base 22 of the weighing bucket 21 then opens to release the pre-determined weight of mixed material into the third hopper 23. A motor 29 drives a centreless auger 24B contained within pipe 24a to convey the mixture leaving the hopper 23 via outlet 24 into the feeder pipe 26 within the feed building 25. The mixture is then distributed into down-pipes 27 ,b,c and falls under gravity into feed trays 28a,b,c. Problems with this prior art system arise due to the location where the liquid additive from container 11 is mixed with the wheat being conveyed along supply pipe 8a. Furthermore, the motion of the material in the supply pipe 8a is such that the chaff and dust from the wheat settles on top of the wheat grains as it passes along the pipe. As a significant proportion of the liquid additive is molasses and it enters the supply pipe 8a as a heavy stream from pipe 14, it has a tendency to bind with the chaff and wheat dust and then coagulate. This can cause the auger to bind up and jam, and the continuing driving power from the motor 9 can then destroy the auger. Expensive mechanical repairs are then needed which can hold up the delivery of feed for 4-6 hours.

These problems are overcome in the method of the present invention which shows in Figure 2 how the known apparatus of Figure 1 can be converted to prevent any risk of the augers 3B or 8B from becoming clogged and seizing up. The apparatus shown in Figure 2 is substantially the sa e s that of Figure 1 and comprises a hopper 1 for the manufactured feed compound which is supported above the ground on legs 2 and has an outlet 3 in its base. Supply pipe 3a is connected to the base of the hopper and extends into the upper region of weighing station 20 where it terminates in vertical down-pipe section 5. Second hopper 6 for whole-wheat is supported above the ground on legs 7 and has outlet 8 in its base. Supply pipe 8a is connected to the outlet 8 in the base of the hopper and extends into the upper region of the weighing station 20 where it terminates in vertical down-pipe section 10. Both ends 5 and 10 of the supply pipes 3a, 8a are positioned above the open top of a weighing bucket 21 which forms part of a weighing device (not shown). The weighing bucket 21 is positioned above third hopper 23 which has outlet 24 in its base connected to pipe 24a which runs to feed building 25 wherein it is connected to feeder pipe 26. Down-pipes 27a,b,c connect the feeder pipe 26 to feed trays 28a,b,c respectively. A flexible centreless auger 3B,8B is mounted in the supply pipes 3a, 8a, powered by motors 4 and 9 respectively. A container 11 for liquid additive is connected to a pump 13 by a pipe 12. In order to convert the apparatus of Figure 1 to automatically coat the granular material without the augers 3B or 8B becoming clogged or seizing up in accordance with the preferred method of the invention, pump 13 is mounted on top of the container 11 , the outlet of the pump being connected by pipe 12 to the weighing station 20. A non-return valve 16 and a filter 17 are mounted in the pipe 12 between the pump 13 and the weighing station 20. Inside the weighing station 20, the pipe 12 is connected to a manifold 18 (shown in more detail in Figure 3) which is connected by a pipe 19 to spray-heads 19a mounted around the circumference of the down-pipe section 10 of the supply pipe 8a from the second hopper 6.

The operation of the liquid supply pump 13 and hence the delivery of liquid from the container 11 to the manifold 18 and spray heads 19a, is controlled by a control unit 30 which monitors the operation of the auger motors 4, 9.

Figure 3 is a view on an enlarged scale of the delivery system for the liquid additive supplied from the liquid container 11 to the spray heads 19a. The system comprises pump 13, liquid delivery pipe 12 connecting the container 11 , non- return valve 16 and filter 17 to the manifold 18. Manifold outlet pipes 19 connect the manifold 18 via adjustable flow nozzles 19b to the spray heads 19a. The pump 13 is electrically connected to a control means 30 which monitors the operation of the auger motors 4, 9. The operation of the control means 30 will be described in more detail later with reference to Figure 4. The container 11 has a capacity of 1000 litres, but this is preferred rather than essential.

Figure 4 is a schematic diagram of the control means 30 for the delivery system shown in Figures 2 and 3, and comprises a first sensor 33, which is connected to the auger motor 4 for the first hopper 1, and a second sensor 34 which is connected to the auger motor 9 for the second hopper 6. Both sensors 33, 34 are connected to a relay 35 which has a 3-way selector switch 36, positionable in an 'off, an 'A' or a 'B' position. The relay 35 is connected to a motor drive unit 37 which receives electrical 240V single-phase mains supply power through a cable 40 via an electrical filter 38 to prevent power surges. The output from the motor drive unit 37 is a screened power cable 39 which is connected to the pump 13 on the liquid container 11. The relay 35 incorporates a known programmable timer which sets a maximum time that a 'run' signal will be sent to the motor drive unit 37. The motor drive unit 37 is provided with a function whereby a delay can be programmed into the unit between when it receives a signal from the relay 35 to when it supplies power via the output power cable 39 to the liquid feed pump 13.

Material from the hoppers 1,6 falls through the respective outlets 3 and 8 into the supply pipes 3a, 8a and is conveyed by the augers 3B,8B powered by their respective motors 4, 9 to the down-pipe sections 5, 10 where it falls under gravity into the weighing bucket 22.

When the auger motor sensors 33, 34 detect that their respective motors 4 and 9 are running, a signal is sent to the relay 35. If the relay selector switch 36 is set to the corresponding motor, (position 'A' for the motor 4 or position 'B' for the motor 9), an electrical run-signal is sent to the motor drive unit 37, for the duration of time programmed into the maximum run-period timer within the relay 35. Once the motor drive unit 37 receives the signal when the programmed delay time has elapsed, electrical power is converted from the single phase 240 volt mains supply, (via the electrical filter 38) into a 3-phase supply and conducted along the output power cable 39 to the pump 13 on the container 11.

The pump 13 then draws liquid from the container 11 out through the supply pipe 12, and supplies it via non-return valve 16 and filter 17, to the manifold 18 located inside the weighing station 20. The liquid additive then leaves the manifold 18 through the manifold outlet pipes 19 and passes via the adjustable flow nozzles 19b to the spray heads 19a which are arranged circumferentially around the end region of the vertical down-pipe section 10 of the supply pipe from the second hopper 6. The ends of the spray heads 19a face inwards towards the centre of the pipe. As the whole-wheat from the second hopper 6 falls under gravity through the down-pipe section 10, liquid from container 11 is sprayed from the spray-heads 19a onto the falling feed, thereby coating it before it reaches the weighing bucket 22.

The auger 3B from the first hopper 1 simultaneously conveys the manufactured feed along its corresponding supply pipe 3a to the down-pipe section 5 where it also falls under gravity into the weighing bucket 21. When the weighing device (not shown) detects that the required pre-determined weight of feed has been reached, the motors 4 and 9 driving the augers 3B,8B stop, thus halting delivery of feed compound and whole- wheat from the hoppers 1, 6. The motor sensors 33, 34 simultaneously detect that the motors 4 and 9 are not running so the relay 35 to which they are connected stops the 'run' signal being sent to the motor drive unit 37. This cuts off the supply of electrical power to the liquid pump 13 thus stopping further liquid being sprayed from the spray heads 19a around the down-pipe 10.

The base 22 of the weighing bucket 21 is then opened to allow the feed mixture in the bucket 22 to fall into the third hopper 23 located below it. The motor 29 drives the auger 24B within the supply pipe 24a to convey the feed mixture from the hopper 23 via outlet 24 along the pipe up into the feed pipe 26 whereby it falls under gravity via down-pipes 27a,b,c into the feed trays 28a,b,c respectively.

From the foregoing description, it can be seen that the invention provides a method of converting a prior art system such as that shown in Figure 1 so that the liquid additive can be sprayed onto the wheat to coat it, rather than being poured onto it. As a result, it is in a finer state, and therefore significantly more effective at being evenly absorbed by the wheat grains. Furthermore, because the liquid is added as the wheat as it falls under gravity past the spray heads 19a, there is no chance of it coagulating in the supply pipe 8a and the auger cannot jam. The function of the control means 30 is to stop the spray of liquid additive as soon as the conveyance of wheat stops when the required weight of feed material has been reached, thus preventing wastage of liquid additive.

Claims

Claims

1. A method of converting an apparatus for mixing an additive with granular material fed from a supply thereof to a weighing station, the apparatus including feed means for feeding the granular material to an outlet at the weighing station and a pump for supplying liquid additive to the granular material as it is fed to the weighing station, the method being characterised by mounting sensing means on the apparatus to sense when granular material is exiting said outlet, positioning spray means to coat said granular material as said material falls under gravity from the outlet into the weighing station and control means for controlling the pump and spray means so that coating liquid is only sprayed onto the granular material while said material is exiting said outlet.

2. A method as claimed in claim 1 wherein the coating liquid is stored in a container and the pump is mounted on the top of the container.

3. A method as claimed in claim 1 or claim 2 wherein the spray means are positioned around the outlet for the granular material where said material falls under gravity into the weighing station.

4. A method as claimed in any of claims 1-3 wherein the feed means is an auger driven by a motor and the sensing means senses when said motor is running.

5. A method as claimed in any preceding claim wherein the control means includes means to convert a 240 volt single phase power supply thereto into a three phase supply for the pump.

6. A method as claimed in any preceding claim wherein compressed air is added to the additive before it is sprayed onto the granular material.