WO2009106794A1

WO2009106794A1 - Apparatus and method for measuring ingredient content

Info

Publication number: WO2009106794A1
Application number: PCT/GB2009/000400
Authority: WO
Inventors: Stephen Neil Shingler
Original assignee: Datastor Systems Limited
Priority date: 2008-02-27
Filing date: 2009-02-13
Publication date: 2009-09-03
Also published as: GB0803592D0

Abstract

An apparatus having a mixer (3) and a measurement device (4) arranged to measure ingredient content of a material in the mixer. The ingredient may be or contain water.

Description

Apparatus And Method For Measuring Ingredient Content

The present invention relates to an apparatus and method for measuring ingredient content of material. Particularly, although not exclusively, the invention relates to an apparatus and method for measuring moisture content of animal feed. Animal feed products are typically sold in either 'meal' or 'pellet' form and are typically manufactured by blending together a wide range of raw materials such as cereals and other natural ingredients.

In known batch processes for the production of animal feed a batch of raw ingredients is weighed and then conveyed, possibly via other process equipment to a mixer where they are mixed for a certain length of time (known as the "dry mix" phase). An amount of water is then added to and mixed with the ingredients in the mixer (known as the "wet mix" phase).

Raw materials for producing animal feed delivered to a manufacturer typically have a wide variation in moisture content and the specific value of moisture content of each batch of a particular raw material often differs from the value specified by its supplier. In addition when the raw materials are stored, prior to use in the manufacturing process, the moisture content of the raw materials may change as the materials may absorb moisture from or lose moisture to their surroundings, depending on how and where the materials are stored. Therefore the dry moisture content of animal feed will generally vary.

Animal feed products are manufactured to a formulation which specifies the desired characteristics of the product. One of these characteristics is maximum moisture content. Manufacturers of animal feed strive to ensure that the moisture content of feed approaches the maximum permitted level as close as possible since this reduces the cost of producing the feed. In doing so however they must ensure that the maximum permitted level is not exceeded, since this could render the feed un-saleable. Therefore, in order to minimise the cost of production, it is necessary to accurately determine the moisture content of the raw ingredients in order to calculate the precise amount of water to be added to the raw ingredients to achieve an end product with the desired moisture content.

Additionally, in the animal feed industry there is demand for large volumes of animal feed product. Production processes run generally continuously in order to satisfy this demand. The efficiency and speed of production therefore has a large effect on the overall costs of production.

It is a first object of the present invention to improve moisture control in a production process.

According to a first aspect of the invention there is provided an apparatus comprising a mixer and a measurement device arranged to measure ingredient content of a material in the mixer.

According to a second aspect of the invention there is provided a method of measuring ingredient content of a material in a mixer, the method comprising providing apparatus according to the first aspect of the invention and measuring the ingredient content of the material in the mixer using the measurement device. Preferably the measurement device is comprised in the mixer. Preferably the measurement device is operative to measure the ingredient content of the material while it is being processed by the mixer.

Preferably the ingredient content of the material in the mixer is measured while the material is being processed by the mixer. Measuring the ingredient content of material while it is being mixed enables the ingredient content of the material to be accurately determined.

Preferably the measurement device is arranged to take a plurality of said measurements. Preferably a plurality of said measurements is taken by the measurement device.

In a process involving dry mix and wet mix phases it is preferred that moisture content is measured during the dry mix phase, enabling the amount of water to be added to the mix to be calculated. If measurements are made during the wet mix phase the results can be misleading unless sufficient time is allowed for free moisture to be absorbed by the mix which can lead to an unacceptable delay in the production process.

Preferably said apparatus is arranged to measure the ingredient content of the material prior to the addition of ingredient in the mixer. Preferably in said method the ingredient content of the material is measured prior to the addition of ingredient in the mixer.

Preferably the measurement device is a microwave based measurement device such as the Moisturescan XT produced by Doescher & Doescher Gmbh. The values measured by the measurement device may be the moisture content of the material. The measurement device is preferably able to take account of the density and temperature of material when determining moisture content.

Mixers typically comprise a container for containing ingredients to be mixed and an agitator which can be moved relative to the container to mix ingredient within the container. A common type of mixer used to produce animal feed is the ribbon type mixer. It comprises a trough-shaped container with a longitudinally extending rotational drive shaft supporting a double helical mixing screw. The mixing screw is rotated relative to the container to mix ingredients in the container. A blade is fitted to each end of the drive shaft and arranged to wipe ingredient from the end faces of the trough shaped container.

When a microwave based measurement device is employed it is preferably mounted to the container of the mixer. Such measurement devices measure the moisture content of ingredient in a region extending from the device, typically of the order of 4cm. If any metal object, such as the agitator of a mixer, extends into or moves within the measurement region of the device it will affect the output of the device, rendering it unusable or inaccurate for determining ingredient content of material in the mixer. With a ribbon mixer, for example, it is convenient for a microwave moisture measurement device to be mounted on an end face of the mixer. If so, the blade fitted to the end of the drive shaft will pass in front of the measurement device as it rotates distorting the output of the device and thus preventing measurements being made whilst the mixer operates. In order to address this problem the apparatus is preferably arranged to ignore any measurement made by a microwave measurement device when its output is disrupted, or potentially disrupted, by a component of the mixer, such as an agitator or blade.

This can be achieved in a number of ways. A means can be provided to determine when a component of the mixer is in or near a measurement region of a measurement device. This can be arranged to cut off a signal from the measurement device when the output of the device is affected by the component. Or it could be arranged to generate a signal when a component of the mixer is in or near a measurement region of the measurement device and to transmit this signal to a processing means arranged to process the output of the measurement device, and arranged to ignore the output of the measurement device when the signal is present. Or, the output of the measurement device could be transmitted to a processing device arranged to analyse the output of the measurement device and, from the output itself, to determine if the output has been affected by a component of the mixer and then disregard an output so affected.

In one embodiment, where the apparatus comprises a microwave based measurement device, the apparatus preferably comprises a determination means arranged to determine when a component of the mixer is located within a microwave field produced by the measurement device. More preferably the apparatus further comprises a means of determining when a blade of the mixer is located within the microwave field produced by the measurement device.

The method preferably further comprises the step of determining, with a determination means, when a component of the mixer is located within the microwave field produced by the measurement device. The determination means may comprise a rotational position sensor arranged to measure the rotational position of a rotating component of the mixer. Alternatively the determination means may comprise a switch which is engaged or disengaged when the mixer component passes into and out of the microwave field. As a further alternative, the determination means may comprise a timing device that generates a timing signal which commences once a component of the mixing device begins to rotate.

The measurement device may be connected at an output to a processing means. The method may comprise the step of outputting the measured value or values to a processing means. Preferably the determination means is connected at an output to the processing means. The method preferably comprises the step of outputting to the processing means, the interval or intervals of time determined by the determination means.

Preferably the processing means is arranged to determine, from the values output to it from the measurement device and the determination means, the values output from the measurement device when the component of the mixer is not in a position which would disrupt the microwave field and to disregard the values output from the measurement device when the component of the mixer is in a position which would disrupt the microwave field. Preferably the processing means is also arranged to calculate an average of the former values and thereby produce an average value for measured ingredient content.

The method may comprise the step of the processing means determining, from the values output to it from the measurement device and from the determination means, the values output from the measurement device when the component of the mixer was not in a position which would disrupt the microwave field and disregarding the values output from the measurement device when the component of the mixer was in a position which would disrupt the microwave field. Preferably the method comprises the step of calculating an average of these determined values. The processing means is preferably connected to a display means and/or a control means. The average value is preferably output to a display means and/or a control means. The control means may be connected to an ingredient dispenser arranged to dispense ingredient to the material in the mixer. The control means may calculate the difference between the average value output from the processing means and a desired value of ingredient content. The control means may then send a signal to the ingredient dispenser in dependence on this difference value in order to attain the desired ingredient content of material in the mixer.

The ingredient may be or contain water. The measurement device may be for measuring moisture content. Preferably the material in the mixer is then passed to a number of different further processing lines, depending upon the end product to be manufactured. The apparatus and method may be for the manufacture of animal feed. The method may include some or all of the following steps: weighing one or more raw materials, conveying raw material(s) to a grinder, grinding raw materials, conveying ground or non-ground raw materials to the mixer and conveying mixed material from the mixer for subsequent processing.

The step of grinding the raw material may occur before the step of weighing the raw material or vice versa.

In order that the invention may be more clearly understood, an embodiment will now be described, by way of example, with reference to the accompanying drawings in which:

Figure 1 shows a flowchart schematically illustrating part of a simplified animal feed manufacturing plant, and

Figure 2 shows a perspective view of a mixer with moisture analyser according to the invention.

Referring to figures 1 and 2, an animal feed manufacturing plant comprises weighers 1 for weighing solid raw ingredients, typically cereals. The weighed ingredients may be conveyed to a grinder 2 in which the ingredients are ground into a suitable form. The ground or non-ground ingredients are then conveyed to a mixer 3. The mixer 3 is a "ribbon type" mixer comprising a container 10 housing a helical screw 11. The helical screw 11 is fixed to a shaft 12 connected to a rotational drive means (not shown). When the mixer 3 is operative, the rotational drive means drives the shaft 12 and the helical screw 11 rotates with the shaft 12, acting so as to mix any ingredients placed within the container 10. A blade 13 is attached at a first end to the shaft 12 and extends from the shaft 12 in a radial direction. The blade 13 rotates with the shaft 12 and is arranged such that, during mixing of ingredients within the mixer 3, the blade 13 scrapes the inside surface at one end of the mixer container 10. This acts to remove any of the mixture that has become adhered to the inner surface of the container 10 in order to facilitate efficient mixing. An equivalent blade (not shown) is provided at the opposite end of the shaft 12.

A moisture sensor 4, in this embodiment a Moisturescan XT produced by Doescher and Doescher Gmbh of Germany, is provided at one end of the mixer 3. The moisture sensor 4 detects the moisture content of the ingredients within the mixer by subjecting a portion of the ingredients to a microwave radiation field and measuring energy lost from the field to the ingredients. The moisture sensor 4 is able to account for both density and temperature of the ingredients measured. The sensor produces a microwave field which extends from the sensor about 4cm into the mixer and in which moisture content of ingredients in the mixer is measured. During each rotation of the shaft 12, the blade 13 passes through the microwave field produced by the moisture sensor 4. As the blade 13 is metallic it disrupts the microwave field as it passes through it. Accordingly, any measurement from the moisture sensor 4 which is taken when the blade 13 passes through the microwave field is affected. The moisture sensor 4 is connected at an output to a processing means 5 and, during mixing of the ingredients, outputs the measured values of moisture content of the ingredients to the processing means 5.

A rotational position sensor 8 is arranged with the shaft 12 to measure the rotational position of the blade 13 as it rotates with the shaft 12. The rotational position sensor 8 is connected at an output to the processing means 5 and outputs, to the processing means 5, the intervals of time when the blade 13 is within the microwave field produced by the moisture sensor 4.

The processing means 5 is arranged to determine, from the values output to it from the moisture sensor 4 and the rotational position sensor 8, the values output from the moisture sensor 4 when the blade 13 of the mixer is not in a position which would disrupt the microwave field and to disregard the values output from the moisture sensor 4 when the blade 13 of the mixer is in a position which would disrupt the microwave field. The processing means 5 is also arranged to calculate an average of the former values and thereby produce an average value for measured moisture content.

The processing means 5 determines, from the values output to it from the moisture sensor 4 and the rotational position sensor 8, the values output from the moisture sensor 4 when the blade 13 of the mixer is not in a position which would disrupt the microwave field and to disregard the values output from the moisture sensor 4 when the blade 13 of the mixer is in a position which would disrupt the microwave field. The processing means 5 then calculates an average of the former values and thereby produces an average value for measured moisture content.

The processing means 5 is connected at an output to a display means 6 and a control means 7 and outputs the average value to the display means 6 and a control means 7. The control means 7 is connected to a water dispenser 9 arranged to dispense water to the ingredients in the mixer 3. The control means 7 calculates the difference between the average value of moisture content produced by the processing means 5 and a desired value of moisture content. The control means 7 then sends a signal to the water dispenser 9, in dependence on this difference value, to dispense an amount of water to the ingredients in the mixer 3 in order to attain the desired moisture content of the ingredients. The dispensed water is then mixed with the ingredients in the mixer 3 in a "wet-mix" phase.

At this stage the ingredients in the mixer 3 are typically passed to a number of different further processing lines to choose from, depending upon the end product to be manufactured. These are common to existing plants and will therefore not be described further.

The above arrangement has been described by way of example only and many variations are possible without departing from the scope of the invention.

Claims

1. An apparatus comprising a mixer (3) and a measurement device (4) arranged to measure ingredient content of a material in the mixer.

2. Apparatus according to claim 1 wherein the measurement device is comprised in the mixer.

3. Apparatus according to either of claims 1 or 2 wherein the measurement device is operative to measure the ingredient content of the material while it is being processed by the mixer.

4. Apparatus according to any preceding claim wherein said apparatus is arranged to measure the ingredient content of the material prior to the addition of ingredient in the mixer.

5. Apparatus according to any preceding claim wherein the measurement device is a microwave based measurement device.

6. Apparatus according to claim 5 wherein the apparatus is arranged to ignore any measurement made by the microwave measurement device when its output is disrupted, or potentially disrupted, by a component (13) of the mixer.

7. Apparatus according to claim 6 wherein the apparatus comprises a determination means (8) arranged to determine when the component of the mixer is located within a microwave field produced by the measurement device.

8. Apparatus according to claim 7 wherein the determination means comprises a rotational position sensor (8) arranged to measure the rotational position of the component of the mixer.

9. Apparatus according to either of claims 7 or 8 wherein the measurement device and determination means is connected at an output to a processing means (5) and the processing means is arranged to determine, from the values output to it from the measurement device and the determination means, the values output from the measurement device when the component of the mixer is not in a position which would disrupt the microwave field and to disregard the values output from the measurement device when the component of the mixer is in a position which would disrupt the microwave field.

10. Apparatus according to claim 9 wherein the processing means is arranged to calculate an average of the values output from the measurement device when the component of the mixer is not in a position which would disrupt the microwave field.

11. Apparatus according to claim 10 wherein the processing means is connected to a control means (7) which is connected to an ingredient dispenser (9) arranged to dispense ingredient to the material in the mixer in dependence on the difference between the average value calculated by the processing means and a desired value of ingredient content.

12. Apparatus according to any of claims 6 to 11 wherein said component of the mixer is a blade (13) of the mixer.

13. Apparatus according to any preceding claim wherein the ingredient is or contains water.

14. Apparatus according to any preceding claim wherein the apparatus is for the manufacture of animal feed.

15. A method of measuring ingredient content of a material in a mixer (3), the method comprising providing apparatus according to any preceding claim and measuring the ingredient content of the material in the mixer using the measurement device.

16. A method according to claim 15 wherein the ingredient content of the material in the mixer is measured while the material is being processed by the mixer.

17. A method according to either of claims 15 or 16 wherein the ingredient content of the material is measured prior to the addition of ingredient in the mixer.

18. A method according to any of claims 15 to 17 wherein the method further comprises the step of determining, with a determination means (8), when a component (13) of the mixer is located within a microwave field produced by the measurement device.

19. A method according to claim 18 wherein the method comprises the steps of outputting the interval or intervals of time determined by the determination means and the measured value or values to a processing means (5) which determines, from these values, the values output from the measurement device when the component of the mixer is not in a position which would disrupt the microwave field and disregarding the values output from the measurement device when the component of the mixer is in a position which would disrupt the microwave field.

20. A method according to claim 19 comprising the step of calculating an average of these determined values and calculating the difference between the average value and a desired value of ingredient content.

21. A method according to claim 20 wherein the control means sends a signal to an ingredient dispenser (9) which dispenses ingredient to material in the mixer in dependence on this difference value in order to attain the desired ingredient content of material in the mixer.

22. A method according to any of claims 15 to 21 wherein said component of the mixer is a blade (13) of the mixer.

23. A method according to any of claims 15 to 22 wherein the ingredient is or contains water.

24. A method according to any of claims 15 to 23 wherein the method is for the manufacture of animal feed.