Recycled material and mixing machinery

• US 6,971,783 B2
• Filed: 07/09/2001
• Issued: 12/06/2005
• Est. Priority Date: 07/19/2000
• Status: Expired due to Fees

• Current Assignee: Keanes Limited
• Original Assignee: Keanes Limited
• Inventors: Owen, Frank
• Primary Examiner(s): Cooley, Charles E.
• Application Number:
  US10/333,489
• Publication Number:
  US 20030164418A1
• Time in Patent Office: 1,611 Days
• Field of Search: 366/2, 366/6, 366/8, 366/14, 366/18, 366/19, 366/20, 366/33, 366/34, 366/35, 366/37, 366/38, 366/50, 374/03, 404/75, 404/92
• US Class Current: 366/6
• CPC Class Codes: B09B 3/25 using mineral binders or matrix
• CPC Class Codes: E02F 5/226 with means for processing the soil, e.g. screening belts, separators; Padding machines
• CPC Class Codes: Y02W 30/91 Use of waste materials as fillers for mortars or concrete

Abstract

Site-won spoil from an excavation which is a predominantly non-granular cohesive material can be converted into a material suitable for immediate use as a backfill material by a process of mechanically mixing the spoil with between 0 and 30% by weight or volume of added granular material and between 1 and 10% by weight or volume of a powder material comprising 1–5% lime or with the addition of 1–5% cement and/or 1–5% pulverized fly ash. The process works well with clay soils and the range of suitable spoil can be extended by adding cement to the powder material. The proportions in the mixture are chosen in dependence on the clay and moisture content of the spoil. A machine which can be set to mix the ingredients and water in the correct proportions on site is also described.

Claims

1. A process for recycling site-won spoil comprising predominantly non-granular cohesive material from an excavation into a material immediately suitable for use as a backfill, comprising the steps of loading extracted site-won spoil into a hopper of a machine for recycling site-won spoil, loading up to 30% added granular material into the hopper, breaking up site-won spoil and mixing it with the added granular material in the hopper with a rotavator, transferring the broken up site-won spoil and granular material from the hopper to a mixing means, adding between 1 and 10% of a powder material comprising lime or lime with the addition of cement and/or pulverised fly ash into the mixing means and mixing the components together into an output material.

2. A process as claimed in claim 1, wherein the site-won spoil comprises at least 20% clay.

3. A process as claimed in claim 1, wherein up to 5% cement is mixed with the spoil.

4. A process as claimed in claim 1, wherein up to 5% lime is mixed with the spoil.

5. A process as claimed in claim 1, wherein up to 5% pulverised fly ash is mixed with the spoil.

6. A process as claimed in claim 1, wherein water is added to the material during mixing.

7. A process as claimed in claim 2, wherein 3% of lime is used as the powder material.

8. A machine for recycling site-won spoil comprising predominantly non-granular cohesive material from an excavation for immediate re-use as a backfill, comprising means for receiving site-won spoil and added granular material, means located in the receiving means for breaking up the site-won spoil and mixing it with the added granular material, mixing means located outside the receiving means having at least one mixing screw for mixing the components and discharging them from the machine, means for transferring the broken up site-won spoil and granular material to the mixing means, means for adding a measured amount of powder material into the mixing means, water supply means providing water supply to the receiving means and the mixing means, and means for controlling the proportions of water, broken up site-won spoil/granular material and powder incorporated into the mix.

9. A machine as claimed in claim 8, further comprising means for storing different mix ratios depending on the site conditions in order to deliver a consistent backfill material.

10. A machine as claimed in claim 8, mounted on a trailer so as to be transportable.