GB2387559A

GB2387559A - Apparatus and method for the automatic coating of granular products

Info

Publication number: GB2387559A
Application number: GB0208712A
Authority: GB
Inventors: Daniel Thomas Exely Ritchie
Original assignee: Forum Products Ltd
Current assignee: Forum Products Ltd
Priority date: 2002-04-16
Filing date: 2002-04-16
Publication date: 2003-10-22
Also published as: GB0208712D0

Abstract

A method and apparatus for automatically coating granular material supplied from storage hoppers (1,6 figure 1) through pipes 3a,8a to a weighing station 20. The granular material falls from outlets 5,10 of supply pipes 3a,8a directly into a funnel 100 which comprises a frusto-conical fabric body 103, a frusto-conical rigid plastic neck 102 and a cylindrical steel-tubing outlet 101. A liquid additive supply pipe 12 connects an additive storage container 11 to coating means comprising a manifold 18, flow valves 19b and manifold outlet pipes 19, and spray heads 19a mounted around the perimeter of the outlet 101. Compressed air 12b is mixed with the liquid additive in the delivery pipe 12 just upstream of the manifold 18. The granular feed material falls through the funnel 100 out of outlet 101 and is coated with liquid additive by the coating means before being collected in weighing bucket 21 of a weighing means (not shown). The granular material may be animal feed.

Description

1 2387559

Improved Apparatus and Method for the Automatic Coating of Granular Products This invention relates to an improved method and apparatus for automatically s coating granular products and is directed to an improvement of the method and apparatus disclosed in our earlier GB patent application no. 0200323.4 Our earlier patent application discloses a method and apparatus for automatically coating granular products, particularly but not exclusively animal feed material, and 10 describes in detail how the product is coated with a liquid additive delivered through spray heads as it falls through the outlet of a down-pipe into weighing means. It has been found however, that the liquid additive delivered through the spray-heads which are located around the perimeter of the down-pipe do not always evenly coat the feed. To solve this problem, and according to a first aspect of the 15 present invention, there is provided an improved method of automatically coating with an additive, granular material fed from a supply thereof to a feeding station comprising the steps of transporting granular material from said supply to a weighing station, discharging said granular material so that said material falls under gravity into the weighing station, coating said granular material with the additive as 20 it falls under gravity into the weighing station, weighing the required predetermined quantity of coated granular material from the weighing station and transporting said coated granular material to the feeding station, the improved method comprising introducing compressed air into the additive before said additive is applied to the granular material.

This improved method ensures a more even delivery from the spray-heads so that the granular can be coated more efficiently and evenly.

It was also found with our earlier invention that because several outlet pipes (in 30 some cases four or more pipes) discharge coated granular material directly into the weighing means, the spray-heads and associated valves mounted on each pipe outlet made the process of adjusting all of the valves to be very time consuming.

- 2 - Furthermore, having to provide spray-heads and supply lines on each outlet substantially increased the capital cost of the equipment.

This problem is solved according to a second aspect of the present invention by 5 providing an improved apparatus for automatically coating with an additive a predetermined quantity of granular material fed from a supply thereof to a feeding station comprising a storage hopper for the granular material, coating means located to apply the coating additive onto the granular material as said material falls under gravity into the weighing means and delivery means for delivering the weighed 10 quantity of coated material to the feeding station, the improved apparatus comprising providing a mixing hopper to receive the granular material before it reaches the weighing means, the coating means being mounted on an outlet for said mixing hopper so that the granular material is coated with additive as it passes through said mixing hopper outlet.

This arrangement allows all of the pipes which deliver granular material to the weighing means to discharge directly into the mixing hopper, so that the feed can be coated with the liquid additive as it drops through the mixing hopper outlet. The advantage provided by this improvement is that only one set of spray heads and 20 additive delivery pipes is needed on the mixing hopper outlet to coat the granular material regardless of the number of granular feed delivery pipes supplying feed thereto. Furthermore, the spray heads are nearer ground level so they are more accessible for maintenance and adjustment, making it easier to deal with any potential blockages at the liquid additive spraying stage.

Conveniently, the mixing hopper is a funnel disposed between the end of the or each feed duct outlet and the weighing means located below them, so the granular material must pass through the funnel from the or each duct to reach the weighing means. In a preferred embodiment, the funnel outlet is a section of steel tube.

Conveniently, said steel tube is galvanised.

- 3 In a preferred embodiment, there is a stiff neck-section around the top of the outlet-section of the funnel. Preferably, the neck section is made of polypropylene.

In a preferred embodiment, the main body of the funnel is a fabric sleeve which forms a chute, and its bottom is connected to the top of the necksection of the 5 outlet of the funnel.

The apparatus preferably also includes control means operable to regulate the delivery of the additive to the coating means. The control means can incorporate a modem to allow remote control over the delivery of the additive to the granular 10 feed material via the coating means if required.

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 the method and apparatus disclosed in our earlier UK patent application no. 0200323.4; Figure 2 shows in more detail the preferred additive delivery system of our earlier UK patent application no. 0200323.4, for spraying additive onto the granular feed 20 product processed by the apparatus shown in Figure 1; Figure 3 shows the improved additive delivery system of the invention, for spraying additive onto the granular feed product; and Figure 4 is an enlarged scrap view of the improved apparatus of the invention.

25 Referring now to Figure 1, there is shown our earlier apparatus which comprises granular material storage hoppers 1,6 with outlets 3,8 and conveyance augers within supply ducts 3a, 8a, powered by auger motors 4,9. The supply ducts 3a, 8a lead into weighing station 20, where they terminate in vertical down-pipe sections 5,10 above weighing bucket 21. Coating means in the form of spray-heads 19a are fitted around 30 down pipe section 10 which are connected by additive manifold outlet pipes 19 to manifold 18 fed from additive storage tank 11 by delivery pipe 12. It should be noted however, that variations on this arrangement are possible, in that the spray heads 19a can be fitted around both down-pipe sections 5,10. Alternatively, there

- 4 can be more than two supply ducts leading into the weighing station 20 above the weighing bucket 21, each having coating means fitted thereto.

The apparatus shown in Figure 1 includes an additive delivery system shown in s greater detail in Figure 2 and comprises pump 13, to draw the liquid additive from the container 11, which is connected to delivery pipe 12, and incorporates non return valve 16 and filter 17 therein. The delivery pipe 12 leads to manifold 18 (also seen in Figure 1) from where manifold outlet pipes 19 connect via adjustable flow valves l9b, to the spray heads 19a located around the outlet 10 of the granular 10 material supply pipe (as shown in Figure 1).

Figure 3 is a schematic version of the improved additive delivery system of the present invention, which includes additional air-feed pipe 12a, which joins the liquid additive delivery pipe 12 just before the manifold 18.

Figure 4 shows the improvement to the apparatus of Figure 1 provided by the invention. For the purpose of illustration, only two supply ducts 3a, 8a are shown, although there could be more. Granular feed material supply ducts 3a,8a enter the weighing station 20 and terminate in vertical downpipe sections 5,10 below which a 20 mixing hopper or funnel 100 is located. The funnel 100 preferably comprises a galvanised steel tube section 101 with a rigid plastic frusto-conical section 102 extending upwardly from top edge lOla. The steel tube section 101 acts as the outlet for the funnel 100. A conical fabric section 103 with an upper edge 104 is attached to top edge 102a of the plastic rigid frusto-conical section 102. The outlets 2s for the supply pipes 5,10 are located directly above the funnel 100 within the area defined by the perimeter of its top edge 104.

The weighing bucket 21 of a weighing means (not shown) is located below the steel outlet tube 101.

Mounted around the perimeter of the steel outlet tube 101 is the coating means, which comprises the inwardly facing spray heads 19a connected by pipes 19 to the manifold 18. Valves l9b can be used to adjust the flow rate of the liquid additive

- 5 supplied from the storage tank 11 to the manifold 18 via delivery pipe 12.

Compressed air 12b is supplied from a source (not shown) via air-feed pipe 12a into the delivery pipe 12 just upstream of the manifold 18.

s The operation of the apparatus will now be described. Granular material such as wheat or feed compound in the hoppers 1,6 falls through their respective outlets 3,8 into the supply ducts 3a, 8a and is conveyed along said ducts by augers, powered by auger motors 4,9, to the down-pipe sections 5,10, where it falls under gravity into the open topped fabric sleeve section 103 of the funnel 100. It is guided 10 downwardly towards the steel outlet tube 101 by the rigid plastic flange 102 which prevents the fabric sagging under the weight of the feed material, should it collect in a recess, crease or fold therein.

Referring to Figure 1, pump 13 draws liquid additive from the container 11 and 15 pumps it through delivery pipe 12, via non-return valve 16 and filter 17 to the manifold 18. Compressed air 12b is supplied through airfeed pipe 12a into the liquid flow of additive in pipe 12 so that a mixture of liquid additive and compressed air is fed to the manifold 18. The addition of the compressed air promotes droplet formation of the additive in the liquid flow as it continues from 20 the manifold 18 through the outlet pipes 19 via the adjustable flow valves 19b to the spray heads 19a. Thus, when the mixture is emitted from the spray heads 19a, it is as a fine mist of significantly smaller droplets than is achieved with our earlier apparatus. This provides a much more even coating of the granular material falling past the spray heads, and also results in much more efficient use being made of the 25 coating additive liquid.

As the material falls through the outlet steel tube 101 of the funnel 100, it is coated with the liquid additive delivered from the spray heads 19a which face inwardly and are circumferentially spaced around the steel outlet-section 101. The coated material 30 then falls into the weighing bucket 21 of the weighing device (not shown), in the same way as the process described in our earlier UK patent application no. 0200323.4.

- 6 A major advantage of placing the spray heads 19a around the outlet 101 of the funnel 100 is that even though several feed tubes 5,10 may empty into the funnel 100, only one set of spray heads 19a is needed around the outlet to coat the feed material. As the spray heads are located at the base of the funnel 100, they are much more accessible for servicing, adjusting or repairing. Also, any blockages in the outlet 101 can be dealt with more easily, as only one outlet may need attention instead of several located much higher as in our earlier apparatus.

Claims

- 7 - Claims

1. An improved method of automatically coating with an additive, granular material fed from a supply thereof to a feeding station comprising steps of s transporting the granular material from said supply to a weighing station, discharging said granular material so that said material falls under gravity into the weighing station, coating said granular material with the additive as it falls under gravity into the weighing station, weighing the required predetermined quantity of coated granular material from the weighing station and transporting said coated 10 granular material to the feeding station, the improved method comprising introducing compressed air into the additive before said additive is applied to the granular material.

2. An improved apparatus for automatically coating with an additive a 15 predetermined quantity of granular material fed from a supply thereof to a feeding station comprising a storage hopper for the granular material, coating means located to apply the coating additive onto the granular material as said material falls under gravity into the weighing means and delivery means for delivering the weighed quantity of coated material to the feeding station, the improved apparatus 20 comprising providing a mixing hopper to receive the granular material before it reaches the weighing means, the coating means being mounted on an outlet for said mixing hopper so that the granular material is coated with additive as it passes through said mixing hopper outlet.

25

3. An apparatus according to claim 2 wherein the mixing hopper is a funnel disposed between the outlet of the or each feed duct and the weighing means so that the granular material must pass through the funnel from the or each duct to reach the weighing means.

30

4. An apparatus according to claim 3 wherein the funnel outlet is a section of steel tube.

- 8

5. An apparatus according to claim 4 wherein a stiff neck-section is provided around the top of the outlet-section of the funnel.

6. An apparatus according to claim 5 wherein the main body of the funnel is a s fabric sleeve which forms a chute, the bottom of said chute being connected to the top of the neck-section of the outlet of the funnel.

7. An apparatus according to any of claims 4 to 6 wherein the steel tube is galvanised.

8. An apparatus according to any of claims 5 to 7 wherein the neck section is made of polypropylene.

9. An apparatus according to any preceding claim further comprising control 15 means operable to regulate the delivery of the liquid additive to the coating means.

10. An apparatus according to claim 9 wherein the control means incorporates a modem to allow remote control over the delivery of the liquid additive to the granular feed material via the coating means.