CA2635509A1

CA2635509A1 - Production system and method for manufacturing lightweight fiber reinforced concrete panels

Info

Publication number: CA2635509A1
Application number: CA 2635509
Authority: CA
Inventors: Shannon Mcnair; Todd Leblanc; Wanda Arnold
Original assignee: VIDABODE GROUP Inc
Current assignee: VIDABODE GROUP Inc
Priority date: 2008-06-20
Filing date: 2008-06-20
Publication date: 2009-12-20
Also published as: WO2009152615A1; CA2669873A1

Abstract

A production system and method for manufacturing individual building blocks or panels of lightweight fiber reinforced concrete, the method consisting of generating raw materials, conveying measured ingredients, mixing ingredients in accordance with a formula of additives, fiber, cement powder, water, and specially coated and sized Expanded Polystyrene (EPS) beads, and conveying the resultant lightweight admixture through distribution into molds on casting elements, is provided. The production line for manufacturing the lightweight fiber reinforced concrete panels has a main conveyance system, material lifts, storage racks, climate controlled curing facility, yard conveyor system, cross-transfer units, return conveyor, wash station, drying station, release agent station, framework manufacturing equipment. The main conveyance system has casting elements which are designed to receive in an operable arrangement frames and molds.
The frames and molds are produced by framework manufacturing equipment based on the design specifications shapes and sizes determined by a CAD system.

Description

PRODUCTION SYSTEM AND METHOD FOR MANUFACTURING
LIGHTWEIGHT FIBER REINFORCED CONCRETE PANELS

FIELD OF THE INVENTION

The invention relates to a system and method for manufacturing lightweight fiber reinforced concrete articles, such as, for example block-shaped or flat rectangular concrete elements.

BACKGROUND OF THE INVENTION

Concrete materials have been made and used, in particular, in the construction field in the past years. Light weight concrete building materials, that incorporate foamed polystyrene particles which are coated, prior to their addition to the concrete mixture, have gained significant importance in the recent years for their improved performance and relative low cost manufacturing.

Research and development into lightweight concrete began, and the idea of lightweight concrete with EPS beads was introduced, in Germany in the early 1980s. Previous early attempts at lightweight concrete did not venture much further than adding EPS beads to concrete in different volumes and mixing it, without addressing the difficulties arising from using foamed polymer particles as ingredient of concrete mixtures.

Use of foamed polymer particles, such as, for example expanded polystyrene, as an additive for building materials is not straightforward. The introduction of granules or beads of foamed plastic material into concrete or plaster posses difficulties in obtaining adequate binding between the concrete and the granules. It is a known problem of building materials of this type that the granules are easily broken away from the concrete or plaster, with the result that the material tends to disintegrate at the edges as the granules break away.

Production line equipments to manufacture these lightweight concrete building materials, for example lightweight concrete panels, using various concrete mixtures are known in the art.

For instance, U.S. Patent No. 3,904,723 issued September 9, 1975 to Prince discloses a method of manufacturing concrete. U.S. Patent No. 4,098,563 issued July 4, 1978 to Prince is a divisional of the above-identified U.S.
Patent directed to the concrete product manufacturing apparatus.

U.S. Patent No. 4,547,331 issued October 15, 1985 to Batstra describes a method and system for manufacturing lightweight shaped concrete materials incorporating sphere-shaped particles of a foamed plastic material with a binder.
Batstra's teachings describe that the foamed plastic material is coated with a firs portion of dry cement and a second portion of dry cement and sufficient water to harden the cement. Batstra teaches that adding a binder and cement and admixing the cement with the spheres of plastic material ensures that the spheres which have been individually coated with the binder will adhere to the cement so that a firm product is obtained consisting of spheres of foamed plastic material lying in a matrix of cement.

PCT International Application No. W095/9723 published on April 13, 1995 to Nordin et al., discloses a method and device for producing reinforcement fibres and adding them to concrete.

PCT International Application No. WO01/19584 published on March 22, 2001 and U.S. Patent No. 6,676,862 issued January 13, 2004 to Jensen, both describe a method and apparatus for efficiently forming individual building units.
The method of Jensen provides the ability to measure the amount of cementitious slurry in each batch in order to control to the extent possibie the

2 quantity of cementitious slurry poured into each mold and the ability to precisely control the dimensions of each building unit produced.

Increasingly, structural stability and ability to withstand major weather events and cope with climates issues (extreme heat/cold) is a key concern of concrete construction.

The invention was made in recognition of the need for a system and method for manufacturing individual building blocks or panels of lightweight concrete with a view to minimizing labor costs, and shortening occupancy waits to meet the demand of the growing market for affordable housing.

SUMMARY OF THE INVENTION

An object of the present invention is, thus, to provide a method and system for manufacturing individual building blocks or panels of lightweight concrete.

In accordance with an aspect of the present invention, there is provided a method including the steps of generating raw materials, conveying measured ingredients, mixing ingredients in accordance with a formula of additives, fiber, cement powder, water, and specially coated and sized Expanded Polystyrene (EPS) beads, and conveying the resultant lightweight admixture through distribution into molds on casting elements.

In accordance with another aspect of the present invention, there is provided a concrete product manufacturing system having storage means for supplying raw materials, including EPS beads and cement; mixer means positioned to receive said raw materials from said storage means and for mixing said raw materials with additives, fiber, and/or water to continuously form a wet concrete mixture; conveying means with molds adjacent said mixer means and in

3 position at all times for continuously receiving said wet concrete mixture from said mixer means into the molds, the molds being adjacent said receiver means for repeatedly receiving charges of said wet concrete mixture from said receiver means to form pre-cured concrete products; curing means, including a climate-controlled curing area; treatment means, including pressure washer, air dryer, and/or mold release agent; distribution means; labeling means for apposing identification and production information labels as well as an electronically readable bar code for identification and "picking" storage on the procured concrete products; and transport means adjacent said molds for successively receiving said pre-cured products from said molds and placing said pre-cured products in a vertical or horizontal palletizing orientation in layers for storage or offsite transportation.

BRIEF DESCRIPTION OF THE DRAWINGS
Exemplary embodiments of the present invention will now be described, by way of example only, in conjunction with the following drawings, in which:

Fig. 1 shows a diagram of the concrete product manufacturing system of the present invention;

Fig. 2 shows a perspective view of the main conveyance system in accordance with an embodiment of the present invention;

Fig. 3 shows a perspective view of the formwork conveyance system of the present invention;

Fig. 4a and 4b show a side and front sectional views, respectively, of the distribution head in accordance with an embodiment of the present invention;

4 Fig. 5 shows the Washdown/Dry-Off/Release Agent Application Station in accordance with an embodiment of the present invention; and Fig. 6 shows a plan top view of the EPS plant layout in accordance witrh a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following description is presented to enable a person skilled in the art or science to which the present invention pertains to make and use the invention, and is provided in the context of a particular application and its requirements.
Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art or science, and the general principles defined herein may be applied to other embodiments and applications without departing from the scope of the invention. Thus, the present invention is not intended to be limited to the embodiments disclosed, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

With reference to the Fig. 1, shown is the concrete product manufacturing system, which has raw material storage bunkers 1 which include, but are not limited to, Expanded Polystyrene (EPS), sand, and cement silos (5, 7, 11), and EPS, sand, and cement bins (6, 8, 12). At least one bunker 13 may be provided with separate compartments for additives, fibers, and water. The sand silo 7 is provided with sand via a sand conveyor 9 which runs from a sand bunker 10, preferably remotely located. The EPS silo 5 is provided with the EPS beads by an EPS beads conveyor 4. The EPS beads are conveniently foamed polystyrene coated with a coating composition which improves adherence of the beads to the cement. From the bins 6, 8, 12, and/or 13 measured quantities of concrete ingredients are poured into the mixer 20.
VPS Process Flow Formwork System The Formwork System processes raw materials to produce framing that is integrated into the Vidacrete panel. Raw materials are conveyed into an Autocon continuous mixture. A CAD System is integrated with the Mixer to provide EDI &
MRP data. The mixed materials are dispensed into a Formwork Material Hopper.
From the Formwork Hopper, the Mixed Material is poured into molds of varying geometry mounted on the Formwork Conveyor. As the poured Formwork moves the length of the Formwork Conveyor (40 feet or more) its cures and is off-loaded automatically onto a power conveyor to the Formwork Cut & Assembly Work Stations. The Formwork framing is assembled and sent to the Infeed Panel Casting Prep Station where it is placed on a 9' wide X 19' long X 1"
thick Casting Element. The top of the casting element effectively becomes the bottom of the panel mold while the Formwork frames the perimeter of the mold.

EPS System EPS Raw Materials are fed into a hopper. A weighing system meters the raw material & a blower unit draws the raw material into the EPS Pre Expander.
Steam is provided to the EPS Pre-Expander by a boiler. Steam expands the EPS material to form beads which are forced into a heated Fluidized Bed Dryer.
A steam heating coil and forced air blower move the beads through An EPS
Bead Coating System. From there the coated Beads are blown into storage silos.

Concrete Batching System Cement, water, sand, EPS Beads and additives are conveyed to a Mixer.
A CAD System is integrated with the Mixer to provide EDI & MRP data. Software for Labeling & Inventory Control is also incorporated. Vidacrete is dispensed from the Mixer directly over the Curing Station onto the Casting Element and into each Formwork Assembly to create -a panel of specific length, width and thickness.

Curing System The Assembled Formwork Framing and Casting Element is conveyed to the Curing Station from the Infeed Panel Casting Prep Station. Vidacrete is poured into the Formwork Assemblies on the Casting Elements as they move under the Mixer. Steam, vibration and time in the Curing Station result in a completed panel exiting the Curing Station.

Prep System The Prep System ensures Formwork Assemblies are returned to the Curing System on clean Casting Elements treated with release agent.

OutFeed Shipping / Storage System After exiting the Curing Station, completed Vidacrete panels are pushed off the Casting Element by an actuator. Completed Panels are conveyed to Shipping or to Storage.

Prep System After Vidacrete Panels are removed, empty Casting Elements are conveyed to the Washdown / Dry-Off / Release Agent Application Station.

It should be noted that the EPS beads are specifically manufactured to the correct size and density for the process. Preferably, EPS pre-expanders 2 which come equipped with "fluid bed dryers" for the finishing of the EPS beads once they have been expanded to the proper size from their original resin state are employed. Once the EPS beads have been treated with the coating composition, they are transported by the EPS bead air conveyor 4 to the EPS silo 5 after which they are sent to specially measured EPS bin 6. The beads in the EPS bin 6 are emptied into the automated concrete batch mixer 20 at the correct time and with the precise volume amount. Sequencing of time and conveyance of EPS
and all other materials/ingredients may be handled by a computer automated system, including a CAD system 60.

As stated above sand is delivered and dumped into a sand bunker 10 located near the concrete manufacturing system. From the sand bunker 10 the sand is conveyed by the sand conveyor system 9 to the 150 ton sand silo 7, preferably located adjacent to the manufacturing plant building near the mixers.

The sand can be aerated and warmed in the sand silo 7 before being conveyed to the mixer 20, as required by the computer automated system. Sand and cement from the cement bin 12 come into the mixers where they are mixed with the other admix items in preparation for distribution.

The lightweight concrete mixture is prepared using a formula of additives, fiber, cement powder, water, and specially coated and sized EPS beads, all of which is bound together in a precise sequence (a) in a twin shaft mixer 20 (b). It is to be noted that in accordance with a preferred embodiment the system requires twin shaft mixers.

In the precise sequence: (a) the twin shaft mixers make up a component of the manufacturing system. The mixers cycle in 90 seconds, meaning that from the time the mixer is loaded with cement, sand, water, additives and EPS beads only approximately 90 seconds will elapse until the pour. Research and development has shown that EPS beads are susceptible to abrasion damage in the mixers. The mixers are designed such that they thoroughly finish he mixing of each batch without damaging the EPS beads; in particular, the twin shaft mixer 20 has mixing paddles designed to draw the EPS beads down into the base admixture, and if said paddles are not designed to specifications, the EPS
beads will float on top of the mix without properly becoming a part of the mass mixture, and will wear down through the abrasive action of the aggregate in the mix.
Consolidation of the mix cannot be realized without the proper mixing technique:
and (b) the sequence requires that the sand, cement, and water be placed in the mixer 20 first, and after several turns of the drum, the additives and fibers are added (specific by weight and volume), and the mixer further rotated. Once it is clear that the contents are thoroughly mixed, the EPS beads are added and the mixer runs for a short time, approximately 10-15 seconds, in order to draw the EPS beads completely into the mix. The entire mixing process takes approximately 90 seconds, and should not exceed 120 seconds.

Prior to the introduction of the casting elements to the mixing, the molds 63 are manufactured and assembled onsite to meet the specifications of the panels to be created. The design specifications, shapes and sizes are determined by the CAD system 60 which is communicated to the assembly site in sequence. Once the frames or molds 63 are created, they are queued for placement on the casting elements. The casting (galvanized face) elements 102, which are preferably custom designed honeycomb core, are lightweight and extremely rigid. These highly rigid casting elements 102 receive the formwork or molds and are transported along the main conveyance system 30 to the mixer 20. The formwork becomes and integral part of the finished panel.

As the casting element 102 passes under the mixers 20 the correct proportion of concrete will be laid into formwork/molds upon the casting elements. In accordance with a preferred embodiment this step is computerized and fully automated. Next the element will pass along the main conveyance system 30 to an automatic roller consolidation process screed (not shown), i.e.
roller screed, bull float, mag floats, etc., which will smooth the concrete to the necessary finish. Part of this component requires that onsite technicians monitor the quality and finish of each panel and ensure that it meets our high quality standards.

The panels may be coded with visible panel identifiers on three sides by the labeling system which is connected and controlled by the computer , . i . . ... . .. . . I . . . . I

automated system 60. This facilitates the correct "picking" of the panels for shipping. This system may be automated so that the identification and selection of the correct panels in the correct sequence can be achieved both on and off site.

The casting elements 102 and panels will then move along the conveyor system 30 to the climate controlled curing area 31. Once the curing process has completed, for example in approximately 3 hours, the panels are removed and raised to a horizontal position where they are conveyed through a tunnel wherein they are sprayed with a sealant. Once outside they are either placed on a yard conveyance system or upon specially designed pallets fro immediate shipping(not shown) which will move them to either immediate transport 50 or temporary storage 40.

The casting element 102, which remains on the conveyance system once the panels are removed as noted above, is cleaned and prepared for the next cycle while the panels are being conveyed out of the building. The conveyor system component handling the panels will maintain them in a horizontal position as they move out to storage and/or raise them 90 degrees into a vertical position as they move into the storage area.

As the casting element 102 moves down the system, it is pressure washed 32 to remove any concrete residue that may be sticking to the casting element. It will go through a drying process facilitated by an air dryer 33 to the next step after which a mold release agent 34 will be applied as part of the automated concrete batch plant and conveyor system.

The casting element will continue along to form placement and onward to the mixers where the concrete will be distributed into the formwork on the casting element in the next cycle.

Panels are designed to meet the customer's needs for a house, commercial building, residential garage, and other structures. The current design for the housing market consists of 4" and 6" thick panels The shape of the panel is determined by door and window openings as well as adjacent panel attachment be it another wall panel or a roof panel. The edges of the panel have to meet dimensional tolerances required by the adjacent panel adhesion.
When the pre-labelled panel is removed from the casting element at the end of the curing area 31 it will have identification and production information as well as an electronically readable bar code for identification and "picking". In the yard conveyance the panels are placed in a simple stacking yard conveyance system where it is then moved to storage or offsite transportation to the site of construct.
With reference to Fig. 2 shown is the main conveyance system 30 Curing Station The Infeed Prepstation Conveyor (101) moves the Casting Element (102) to the Gantry Lift Infeed (103). At this point in the process the Casting Element (102) carries the formwork assemblies and was sprayed with release agent. The Gantry Lift Infeed (103) moves the Casting Element (102) vertically to the uppermost level of the Curing Station. From there it is moved horizontally under the Pour Station. Vidacrete is metered onto the Casting Element and into the Formwork Assemblies. (104) shows a Pour Station / Poured Panel. Conveyors and Gantry convey using conventional mechanical drives. The Top Infeed Cross Transfer Conveyor (105) moves the Pour Station / Poured Panel (104) into position for a 90 degree change of direction. Although not shown at this point to simplify the schematic, a Cross Transfer Actuator as shown by (113) accomplishes the directional change without changing the orientation of the Casting Element. To accommodate changes in direction of the casting element, speed changes are made by drive controllers. A Cross Transfer Actuator (113) is located at every 90 degree corner. The Top Infeed Center Transfer Conveyor (106) moves the Casting Element into position for the next change in direction.

The Curing Station Enclosure (107) maintains the ambient conditions of temperature and humidity inside the Curing Station. The Live Steam Pipe /
Nozzle Assembly (108) is controlled to provides optimum conditions. Top Conveyor Level 1 (109) moves the Casting Element to the next Cross Transfer Conveyor (1011). A Vibrator (110) consolidates the mix for a preset time period after the pour. A Cross Transfer Center Conveyor (112) moves the Casting Element into position for the next change in direction. Again, a Cross Transfer Actuator (113) accomplishes the directional change without changing the orientation of the Casting Element. Curing Downflow Gantry (114) moves the Casting Element to the next level down. Curing Conveyor Level 2 (115) moves the Casting Element to Cross Transfer Conveyor Level 2 (116).

A Cross Transfer Center Conveyor similar to (112), but located on Level 2 moves the Casting Element into position for the next change in direction. A Cross Transfer Actuator similar to (113), but on Level 2 accomplishes the directional change without changing the orientation of the Casting Element. Curing Downflow Gantry (114) moves the Casting Element to the next level down.
Curing Conveyor Level 3 moves the Casting Element to Cross Transfer Conveyor Level 3 (117).

A Cross Transfer Center Conveyor similar to (112), located on Level 3 moves the Casting Element into position for the next change in direction. A Cross Transfer Actuator similar to (113), but on Level 3 accomplishes the directional change without changing the orientation of the Casting Element. Curing Downflow Gantry (114) moves the Casting Element to the next level down. Curing Conveyor Level 3 moves the Casting Element to Cross Transfer Conveyor Level 4 (118).

A Cross Transfer Center Conveyor similar to (112), located on Level 4 moves the Casting Element into position for the next change in direction. A Cross Transfer Actuator similar to (113), but on Level 4 accomplishes the directional change without changing the orientation of the Casting Element. Curing Downflow Gantry (114) moves the Casting Element to the next level down.
Curing Conveyor Level 3 moves the Casting Element to Cross Transfer Conveyor Level 5 (119).

A Cross Transfer Center Conveyor similar to (112), located on Level 5 moves the Casting Element into position for the next change in direction. A Cross Transfer Actuator similar to (113), but on Level 5 accomplishes the directional change without changing the orientation of the Casting Element. Curing Downflow Gantry (114) moves the Casting Element to the next level down.
Curing Conveyor Level 3 moves the Casting Element to Cross Transfer Conveyor Level 6 (120).

Outfeed Chain Deck Conveyor (121) moves the Casting Element out of the Curing Station. After exiting the Curing Station the completed panel is pushed off the Casting Element by a Cross Transfer Actuator (113). The Casting Element is conveyed to the Wash / Dry / Release Conveyor Washdown Station by the Cross Transfer Conveyor to the Washdown Station (125) where the soiled Casting Element is cleaned with a washdown solution, dried and sprayed with release agent. From there it is conveyed to the Panel Casting Prep Station where the Formwork Assemblies are placed on the Casting Element. From here the process is repeated by moving the Formwork Assembies on the Preped Casting Element on the Infeed Prepstation Conveyor (101) to the Gantry Lift Infeed (103).
The Completed Panel (124) moves to Conveyor Outfeed Shipping / Storage System (131) for further processing.
Referring now to Fig. 3 shown is the formwork conveyance system in accordance with an embodiment of the present invention.
Formwork Conveyor A continuous mixer pours into the Formwork Hopper. The Formwork Hopper dispenses the mixed formwork material directly into the formwork molds. The Hopper is equipped with dispensers. The molds are conveyed under the hopper dispensers while the mixed formwork material is being poured. The Slat Conveyor Leading Edge (201) is where the pour starts. The Slat Conveyor Trailing Edge (202) represents the maximum possible length of a Form. The length of the Conveyor and speed are based on the curing time required for the form to harden enough to remove from the mold. The Slat Conveyor Belt (203) allows continuous casting to occur using multiple series of formwork molds.
The number of forms that can be cast simultaneously is determined from the width of the Slat Conveyor Belt (203) and the width of the Form Molds used. Form Molds are fastened to the Slat Conveyor Belt (203). Relatively short lengths of Form Molds interconnect so that that they rotate effectively seamlessly on the Slat Conveyor Belt (203). Rotation occurs during non-pour periods in the cycle.
Form 1 Mold (204) represents the first in a series of Form Molds connected to the Slat Conveyor Belt (203) by the Mold To Belt Fastener (205). To produce a specific lengths using Form 1 Mold (204), Form 1 End Cap / Divider Leading (206) is inserted at the leading edge and Form 1 End Cap / Divider Trailing (207) is inserted at the trailing edge. Form 1 (208) is conveyed for a predetermined period of time so that it is cured sufficiently enough to be safely removed from the Mold. Removal is accomplished automatically as Form 1 Mold (204) begins its rotation around the conveyor. The empty Form 1 Mold (204) returns for the next pour. Form N End Cap / Divider Leading (209) and Form N End Cap / Divider Trailing Leading (210) are used to produce Form N (211). Form N (211) is the last Form on the Conveyor. Several Forms Molds (not shown) may be fastened to the Conveyor between Form 1(208) and Form N (211) to produce additional Forms.

Fig. 4a and 4b show a side and front sectional views, respectively, of the distribution head. The distribution head consists of seven (7) clamshell gates that are aligned straight along the bottom of the unit. Each gate operates independently and is manipulated through batch control software and hardware for opening and closing sequencing. The batched crete is deposited into the distribution gate which receives volumes based on production parameters dictated by CAD drawings which determine the volume based upon the dimensions of the panel (width x length). The appropriate sequencing of gates is determined by the placement of the forms on the casting elements. Initially the sequencing will be done manually until the system "learns" the sequencing and a database of volume, sequence and dimension are determined and catalogued.
Fig. 5 shows the Washdown/Dry-Off/Release Agent Application Station.

Out-fed Vidacrete Panels from the Curing Station are removed from the Casting Element (W1). The Casting Element (W1) is conveyed in the prescribed direction (W2) under the Wash down/Dry-off/Release agent application Station (W2). A pump delivers the wash down liquid at the required pressure from a reservoir to the wash-down liquid feed line (W3). A Wash down Supply/Manifold (W4) houses the Wash down Spray Nozzles (W5). The Wash down Spray (W6) is directed onto the Casting Element (W1). A Rotating Brush (W7) scrubs the surface of the casting element as it moves by. The Rotating Brush (W7) is indirectly rotated by a brush drive motor (W8) and a Brush Speed Reducer (W9).
The motor may be electric, pneumatic or hydraulic. Drives may be chain, belt or direct. The speed reducer may be a gear type; or use electric speed modulation, pneumatic speed modulation or hydraulic speed modulation. Where practical mechanical, electrical & ancillary components are located on the Hardware Mounting Framework (W10). The Wash down Liquid Containment Hood (W20) minimizes overspray. A Brush to Casting Element Surface Contact Springs Adjustment Assembly (W11) maintains contact pressure between the Rotating Brush (W7) and the Casting Element (W1). A Squeegee (W12) starts the drying process by removing unwanted liquid as the Casting Element (W1) moves under it. A Forced Air Blower / Motor Assembly (W13) develops airflow for drying.
The Blower Hood (W14) directs Forced Air (W15) at the Casting Element (W1). A
pump delivers the release agent) at the required pressure from a reservoir to the Release Agent Feed Line (W16). A Release Agent Supply/Manifold (W17) distributes liquid to the Release Agent Supply Nozzles (W18) to apply the Release Agent Spray (W19). The prepped Casting Element is conveyed to the Infeed Prep Station to have the Formwork placed on the panel.

Referring now to Fig. 6 shown is a preferred layout of an EPS plant in accordance with the present invention. The x and y axis are in feet for preferred, but not limited to, placement reference only.