GB2105969A

GB2105969A - Production of animal feed by a double pelleting process

Info

Publication number: GB2105969A
Application number: GB08226736A
Authority: GB
Inventors: Richard Quentin Carmichael
Original assignee: Simon Barron Ltd
Current assignee: Simon Barron Ltd
Priority date: 1981-09-19
Filing date: 1982-09-17
Publication date: 1983-04-07

Abstract

Disclosed is a method of producing pelleted animal feed by (i) passing a supply of feed meal through a feeder/conditioner to which viscous liquids such as fats and molasses may also be supplied, (ii) working the conditioned meal into pellets in a first pelleting press, (iii) ripening the pellets by heating them for a predetermined period, (iv) conditioning the ripened pellets to increase the surface moisture thereon and then working them in a second pelleting press and, (v) cooling the final product. The double pelleting process allows increased quantities of viscous liquids to be added to the initial meal, and a product of superior quality to be produced.

Description

SPECIFICATION A method of producing pelleted animal feed THIS INVENTION concerns a method of producing pelleted animal feed.

It has long been a problem when producing animal feed in pelleted form to introduce into the feed, prior to pelleting, such viscous liquids as high fats, molasses and other materials having a high moisture content. The problem arises because of the difficulty of pelleting materials having a high content of such viscous liquids which cause the material to issue from the pelleting press in a sticky and unmanageable form or as soft pellets. Further, it is difficult to ensure that such liquids are uniformly and completely absorbed into the feed meal.

An object of the present invention is to provide a method of producing pelleted animal feed, wherein this problem is overcome to an extent which permits the inclusion of a higher content of liquids such as fats and molasses.

According to the present invention there is provided a method of producing pelleted animal feed, comprising the steps of taking a supply of feed meal, working same into pellets in a first press, allowing the pellets to ripen for a pre-determined dwell period, and passing the ripened pellets to a second pelleting press to produce the final pelleted product.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawing which is a flow diagram of a process for producing animal feed, and incorporating the process steps of the present invention.

At the start of the process raw animal feed consisting of such typical components as cereals, grass, proteins, etc. with additional ingredients such as essential vitamins, minerals and drugs at an average moisture content of approximately 14 per cent, is introduced into a feeder/conditioner 10 which, with the use of steam, pre-conditions it by the adjustment of its moisture content and/or temperature, and permits the addition at line 11 of certain viscous liquids such as fats and molasses. This unit also determines the rate at which the meal is fed to a first pelleting press 12 which converts it into pellets having a soft and crumbly consistency.The pellets are then fed to a ripener 13 in which they are retained for a predetermined period in the region of 20 minutes and in which the temperature of the pellets is maintained above a certain minimum, and typically within the range of 40 to 500 centigrade. At higher temperatures the existence of bacteria can be determined and controlled. These conditions permit the fats and molasses to become fully absorbed into the fibrous meal without deterioration of the majority of the micro-ingredients such as vitamins, minerals and drugs.

After the dwell period in the ripener 13, the soft pellets are passed to a conditioner 14 where, for example, steam or water may be added to increase surface moisture to aid extrusion of the pelleted meal which is then repelleted in a second pelleting press 15 to produce pellets having a more durable consistency. The pellets leaving the press 15 pass through a cooler 16 from which issues the final product. Hot and moist air at between 40 and 80"C extracted from the cooler 16 is supplied to the ripener 13 to maintain the working temperature therein. If necessary, a heat exchanger 17 may be included in the air return line to the ripener, in which excess moisture is removed from the air stream which can additionally be heated if necessary.

By subjecting the material to two pelleting stages it is thus possible to include increased quantities of fats and molasses in the meal, when compared with conventional single pelleting processes. Also, the addition of increased viscous material of this kind together with the action of the first pellet stage assists in binding together the fibrous material and the micro-ingredients therein to an extent where the air draught passing through the ripener cannot dislodge from the meal the light or powdery constituents thereof.

Additionally, double pelleting affords greater control over the moisture content of the final product.

Higher meal temperatures can be obtained without exceeding the normal conditioned meal moisture limit of about 18%. As is well known, higher meal temperatures improve the pellet quality and reduce the electrical power required at the pelleting press.

One method of increasing temperature is first to dry the raw materials to below 14% moisture, which then allows the addition of a greater quantity of steam before pelletising. This method requires additional energy for the initial drying and for producing the extra steam. Double pelleting with hot moist air re-cycled to the flow line between the pelleting operations achieves the same result without the need for pre-drying the meal and with only a small addition of steam at the final conditioner 14 to lubricate the meal and enhance the efficiency of the second pelleting operation.

Further advantages accrue from the double pelleting action, namely that the first pelleting press requires only low energy input in view of the lubricating characteristics of the fat, molasses or other viscous liquid, whilst a product of superior quality is produced.

In a modified form of the process, the hot and moist air recycled from the cooler 16 is fed, not to the ripener 13, but to the input line 11. In this case, the heat exchanger 17 is not required and the ability to use less steam in feeder/conditioner 10 is achieved.

1. A method of producing pelleted animal feed, comprising the steps of taking a supply of feed meal, working same into pellets in a first press, allowing the pellets to ripen for a pre-determined dwell period and passing the ripened pellets to a second pelleting press to produce the final pelleted product.

2. A method according to Claim 1, wherein said feed meal is pre-conditioned, by the use of steam, to adjust its moisture and temperature.

3. A method according to Claim 1 or Claim 2, wherein to said feed meal is added a supply of viscous liquids such as fats and molasses, prior to entry into said first pelleting press.

4. A method according to any preceding claim, wherein the pellets issuing from said first pelleting

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION A method of producing pelleted animal feed THIS INVENTION concerns a method of producing pelleted animal feed. It has long been a problem when producing animal feed in pelleted form to introduce into the feed, prior to pelleting, such viscous liquids as high fats, molasses and other materials having a high moisture content. The problem arises because of the difficulty of pelleting materials having a high content of such viscous liquids which cause the material to issue from the pelleting press in a sticky and unmanageable form or as soft pellets. Further, it is difficult to ensure that such liquids are uniformly and completely absorbed into the feed meal. An object of the present invention is to provide a method of producing pelleted animal feed, wherein this problem is overcome to an extent which permits the inclusion of a higher content of liquids such as fats and molasses. According to the present invention there is provided a method of producing pelleted animal feed, comprising the steps of taking a supply of feed meal, working same into pellets in a first press, allowing the pellets to ripen for a pre-determined dwell period, and passing the ripened pellets to a second pelleting press to produce the final pelleted product. An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawing which is a flow diagram of a process for producing animal feed, and incorporating the process steps of the present invention. At the start of the process raw animal feed consisting of such typical components as cereals, grass, proteins, etc. with additional ingredients such as essential vitamins, minerals and drugs at an average moisture content of approximately 14 per cent, is introduced into a feeder/conditioner 10 which, with the use of steam, pre-conditions it by the adjustment of its moisture content and/or temperature, and permits the addition at line 11 of certain viscous liquids such as fats and molasses. This unit also determines the rate at which the meal is fed to a first pelleting press 12 which converts it into pellets having a soft and crumbly consistency.The pellets are then fed to a ripener 13 in which they are retained for a predetermined period in the region of 20 minutes and in which the temperature of the pellets is maintained above a certain minimum, and typically within the range of 40 to 500 centigrade. At higher temperatures the existence of bacteria can be determined and controlled. These conditions permit the fats and molasses to become fully absorbed into the fibrous meal without deterioration of the majority of the micro-ingredients such as vitamins, minerals and drugs. After the dwell period in the ripener 13, the soft pellets are passed to a conditioner 14 where, for example, steam or water may be added to increase surface moisture to aid extrusion of the pelleted meal which is then repelleted in a second pelleting press 15 to produce pellets having a more durable consistency. The pellets leaving the press 15 pass through a cooler 16 from which issues the final product. Hot and moist air at between 40 and 80"C extracted from the cooler 16 is supplied to the ripener 13 to maintain the working temperature therein. If necessary, a heat exchanger 17 may be included in the air return line to the ripener, in which excess moisture is removed from the air stream which can additionally be heated if necessary. By subjecting the material to two pelleting stages it is thus possible to include increased quantities of fats and molasses in the meal, when compared with conventional single pelleting processes. Also, the addition of increased viscous material of this kind together with the action of the first pellet stage assists in binding together the fibrous material and the micro-ingredients therein to an extent where the air draught passing through the ripener cannot dislodge from the meal the light or powdery constituents thereof. Additionally, double pelleting affords greater control over the moisture content of the final product. Higher meal temperatures can be obtained without exceeding the normal conditioned meal moisture limit of about 18%. As is well known, higher meal temperatures improve the pellet quality and reduce the electrical power required at the pelleting press. One method of increasing temperature is first to dry the raw materials to below 14% moisture, which then allows the addition of a greater quantity of steam before pelletising. This method requires additional energy for the initial drying and for producing the extra steam. Double pelleting with hot moist air re-cycled to the flow line between the pelleting operations achieves the same result without the need for pre-drying the meal and with only a small addition of steam at the final conditioner 14 to lubricate the meal and enhance the efficiency of the second pelleting operation. Further advantages accrue from the double pelleting action, namely that the first pelleting press requires only low energy input in view of the lubricating characteristics of the fat, molasses or other viscous liquid, whilst a product of superior quality is produced. In a modified form of the process, the hot and moist air recycled from the cooler 16 is fed, not to the ripener 13, but to the input line 11. In this case, the heat exchanger 17 is not required and the ability to use less steam in feeder/conditioner 10 is achieved. CLAIMS

4. A method according to any preceding claim, wherein the pellets issuing from said first pelleting press are ripened whilst maintaining the temperature of the pellets at least at 40"C thus to permit the liquid content of said pellets to become fully absorbed into the solids substantially without deterioration of the principal ingredients.

5. A method according to any preceding claim, wherein steam or water is added to the pellets issuing from said first press, to increase the surface moisture of the pellets thus to aid extrusion in the second pelleting press.

6. A method according to any preceding claim, wherein the pellets issuing from said second press are passed to a cooler from which hot moist air is extracted and recycled to the pellets in the ripening stage.

7. A method according to any one of Claims 1 to 5 wherein the pellets issuing from said second pelleting press are passed to a cooler from which hot moist air is recycled to the pellets prior to entry into said first pelleting press.

8. A method according to Claim 6 wherein said recycled air is further heated in a heat exchanger.