GB2136585A

GB2136585A - Mixing and weighing materials

Info

Publication number: GB2136585A
Application number: GB08307111A
Authority: GB
Inventors: John Peter Moore
Original assignee: PARKER PLC FREDERICK
Current assignee: PARKER PLC FREDERICK
Priority date: 1983-03-15
Filing date: 1983-03-15
Publication date: 1984-09-19
Also published as: GB8307111D0; GB2136585B

Abstract

Materials such as particulate solids, aggregates, sand, bitumen, water, oil and so on may be added in turn to a mixing apparatus while a mixing operation is in progress. Each constituent is added singly and gradually until the weight of the apparatus has increased by an amount equivalent to the desired weight to be added. The next constituent is then added in the same way until all the constituents are mixed.

Description

SPECIFICATION Improvements in or relating to the weighing of materials.

The invention is concerned with improvements in or relating to the weighting of materials, particularly materials capable of being mixed. Such materials may, for example, include particulate solid and porous materials and liquids of various viscosities as required.

Where a number of materials are required to be mixed together, it is conventional practice to weigh out the constituent materials in apparatus separate from a mixing chamber and then transfer each constituent to the chamber for mixing.

The present invention provides a method of mixing a desired weight of materials comprising providing a mixing apparatus including a mixing chamber, monitoring the weight of the apparatus when the chamber is empty, adding material to the chamber while a mixing operation is in progress and monitoring the increase in weight of the apparatus until said increase equals the desired weight of materials.

Advantageously, a plurality of materials may be mixed in a desired weight ratio by adding a first constituent material to the mixing chamber until the weight increase equals the desired weight of the first constituent material, adding a further constituent material until a further weight increase equals the desired weight of the second constituent material and continuing in this way as required until all constituents are mixed.

Where convenient, a constituent material may aiso be added to the operating mixing chamber which material is blended externally of the chamber; Mixing apparatus suitable for carrying out the method above described may advantageously include mounting means incorporating load-detection devices. For example, the apparatus may be mounted upon beams incorporating load cells, or may be suspended by an arrangement incorporating a device capable of detecting increases in tension.

Any suitable mixing apparatus may be used, incorporating screws, paddles or the like, operating about vertical, horizontal or any conventional disposed axis. It is advantageous to provide means to isolate, for example, the load cells from the undue effects of vibration from the mixing operation, and this may be achieved simply by the insertion of suitable damping pads or the like.

An example of the carrying out of the method according to the invention will now be described. It will be understood that the description, which is to be read with reference to the drawings, is given by way of example only and not by way of limitation.

In the drawings: Figure 1 is a plan view of a paddle mixing machine; and Figure 2 is a side view of the machine of Figure 1.

The mixing machine comprises a mixing chamber 2 containing two horizontally-disposed shafts 4 mounted in bearings 6. Each shaft supports a plurality of paddle-shaped mixing blades arranged to inter-leave during operation to improve the mixing of materials. The machine is suitable for use, for example, with asphalt, bitumen tar macadam mixtures and the like, or with concrete or other cementitious materials, and lean mix, wet mix, oil gravel, base mix, continuous or batch.

The entire machine, including a prime mover and drive arrangement of a motor drive belt 8 and associated equipment is mounted upon four spaced beams 10, each incorporating a load cell. A vibration damping pad 12 is interposed between each beam 10 and the structure of the chamber 2 (see Figure 2).

When the machine is set up for operation a reading is received at a console (not shown) from the load cells. This reading is adjusted to sero although this is not essential, and the mixing operation commences with addition of, in the present example, agreegate material (solids and liquids such as agreegates, sands, filler, cement, bitumens, water, emulsions, oils, etc) to the chamber. This increase in weight is indicated by the console reading and additions are continued until the required weight of aggregate has been added and is being mixed. It is probable that a slight continuous fluctuation in the reading occurs due to at least in part to some of the aggregate being out of contact with both the paddles and the chamber wall due to the agitation of the mixing operation, but surprisingly this does not greatly affect the steadiness of the reading.Moreover, it has been found that where this fluctuation is measurable an average reading taken between adjacent high and low readings will correspond within operating tolerances with a static reading, i.e. one taken with the mixer having been halted during its operation.

Various modifications may be made within the scope of the invention.

1. A method of mixing a predetermined weight of materials comprising providing a mixing apparatus including mixing devices received within a mixing chamber, monitoring the weight of the apparatus when the chamber is empty, adding material to the chamber in a gradual manner concomitant with a mixing operation carried out by the mixing devices and monitoring the increase in weight of the apparatus until said increase is equivalent to the desired weight of material.

2. A method according to claim 1, wherein a plurality of materials are mixed in a desired weight ratio by gradually adding a first constituent material to the mixing chamber until the weight increase is equivalent to the desired weight of the first constituent material, adding a further constituent material until a further weight increase is equivalent to the desired weight of the second constituent material and continuing in this way as required until all constituents are mixed.

3. A method as claimed in either one of claims 1 and 2, wherein at least one constituent material is preblended externally of the chamber.

4. A method according to any one of the preceding claims wherein a weight reading is continuously

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

Claims

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

SPECIFICATION Improvements in or relating to the weighing of materials.

The invention is concerned with improvements in or relating to the weighting of materials, particularly materials capable of being mixed. Such materials may, for example, include particulate solid and porous materials and liquids of various viscosities as required.

Where a number of materials are required to be mixed together, it is conventional practice to weigh out the constituent materials in apparatus separate from a mixing chamber and then transfer each constituent to the chamber for mixing.

The present invention provides a method of mixing a desired weight of materials comprising providing a mixing apparatus including a mixing chamber, monitoring the weight of the apparatus when the chamber is empty, adding material to the chamber while a mixing operation is in progress and monitoring the increase in weight of the apparatus until said increase equals the desired weight of materials.

Advantageously, a plurality of materials may be mixed in a desired weight ratio by adding a first constituent material to the mixing chamber until the weight increase equals the desired weight of the first constituent material, adding a further constituent material until a further weight increase equals the desired weight of the second constituent material and continuing in this way as required until all constituents are mixed.

Where convenient, a constituent material may aiso be added to the operating mixing chamber which material is blended externally of the chamber; Mixing apparatus suitable for carrying out the method above described may advantageously include mounting means incorporating load-detection devices. For example, the apparatus may be mounted upon beams incorporating load cells, or may be suspended by an arrangement incorporating a device capable of detecting increases in tension.

Any suitable mixing apparatus may be used, incorporating screws, paddles or the like, operating about vertical, horizontal or any conventional disposed axis. It is advantageous to provide means to isolate, for example, the load cells from the undue effects of vibration from the mixing operation, and this may be achieved simply by the insertion of suitable damping pads or the like.

An example of the carrying out of the method according to the invention will now be described. It will be understood that the description, which is to be read with reference to the drawings, is given by way of example only and not by way of limitation.

In the drawings: Figure 1 is a plan view of a paddle mixing machine; and Figure 2 is a side view of the machine of Figure 1.

The mixing machine comprises a mixing chamber 2 containing two horizontally-disposed shafts 4 mounted in bearings 6. Each shaft supports a plurality of paddle-shaped mixing blades arranged to inter-leave during operation to improve the mixing of materials. The machine is suitable for use, for example, with asphalt, bitumen tar macadam mixtures and the like, or with concrete or other cementitious materials, and lean mix, wet mix, oil gravel, base mix, continuous or batch.

The entire machine, including a prime mover and drive arrangement of a motor drive belt 8 and associated equipment is mounted upon four spaced beams 10, each incorporating a load cell. A vibration damping pad 12 is interposed between each beam

10 and the structure of the chamber 2 (see Figure 2).

When the machine is set up for operation a reading is received at a console (not shown) from the load cells. This reading is adjusted to sero although this is not essential, and the mixing operation commences with addition of, in the present example, agreegate material (solids and liquids such as agreegates, sands, filler, cement, bitumens, water, emulsions, oils, etc) to the chamber. This increase in weight is indicated by the console reading and additions are continued until the required weight of aggregate has been added and is being mixed. It is probable that a slight continuous fluctuation in the reading occurs due to at least in part to some of the aggregate being out of contact with both the paddles and the chamber wall due to the agitation of the mixing operation, but surprisingly this does not greatly affect the steadiness of the reading.Moreover, it has been found that where this fluctuation is measurable an average reading taken between adjacent high and low readings will correspond within operating tolerances with a static reading, i.e. one taken with the mixer having been halted during its operation.

Various modifications may be made within the scope of the invention.

1. A method of mixing a predetermined weight of materials comprising providing a mixing apparatus including mixing devices received within a mixing chamber, monitoring the weight of the apparatus when the chamber is empty, adding material to the chamber in a gradual manner concomitant with a mixing operation carried out by the mixing devices and monitoring the increase in weight of the apparatus until said increase is equivalent to the desired weight of material.

2. A method according to claim 1, wherein a plurality of materials are mixed in a desired weight ratio by gradually adding a first constituent material to the mixing chamber until the weight increase is equivalent to the desired weight of the first constituent material, adding a further constituent material until a further weight increase is equivalent to the desired weight of the second constituent material and continuing in this way as required until all constituents are mixed.

3. A method as claimed in either one of claims 1 and 2, wherein at least one constituent material is preblended externally of the chamber.

4. A method according to any one of the preceding claims wherein a weight reading is continuously provided during the additions of constituent material, and means are provided for averaging out continuous fluctuations in said reading.

5. Apparatus for carrying out the method according to claim 1, comprising a mixing chamber in which are received mixing devices, mounting means for the apparatus comprising monitoring means sensitive to weight changes.

6. Apparatus as claimed in claim 5, wherein the weight change sensitive means are load cells incorporated in beams of the mounting means.

7. Apparatus as claimed in claim 5, wherein the weight change sensitive means are strain gauges.

8. Apparatus as claimed in any one of claims 5 to 7, wherein vibration damping means are provided to isolate the means sensitive to weight changes at least partially from the effects of vibration from the operation of the mixing devices.

9. A method of mixing a predetermined weight of materials substantially as hereinbefore described with reference to the drawings.

10. Apparatus for carrying outthe method of claim 9, constructed arranged and adapted to operate substantially as hereinbefore described with reference to and as shown in the drawings.