Vacuum extrusion system for production of cement-based articles
AssigneeThe American Equipment Systems Corporation
InventorTerence J. Fellabaum
Life of this patent
Estimating the term…
Abstract
A system for making extruded cement-based articles. The process can include forming a cement-based feed mixture including water, aggregate and binder and directing the feed mixture to a vacuum zone, wherein sufficient vacuum is maintained in the vacuum zone to remove entrained air and, preferably, excess water, from the feed mixture. The feed mixture is held in the vacuum zone at a negative pressure for a time sufficient to form a vacuum-treated or densified mixture. The vacuum-treated or densified mixture is passed through an extruder at an elevated pressure to provide an extruded cement-based article.
Claims57
A process of forming an extruded cement-based article, comprising the steps of:
- directing a cement-based feed mixture through an extruder at an elevated pressure and through a die chamber to a final die to thereby provide an extruded cement-based article;
- and,
- applying a vibrating force to the die chamber to facilitate the extruding of said article without transferring any substantial vibration to said extruder and said final die.
The process of clam 2, wherein said second volume of water is sufficient to provide excess water to the final feed mixture.
A process of forming an extruded cement-based article, which process includes forming a cement-based mixture from starting ingredients that include water, aggregate and hydratable binder and passing the mixture through an extruder, a die chamber adjacent to the extruder, and a final die adjaccnt to the die chamber, the improvement comprising the step of selectively vibrating the die chamber to provide substantial movement of the die chamber with substantial isolation of the extruder and the final die from the vibration.
A process of forming an extruded cement-based article, comprising the steps of:
- forming a cement-based mixture comprising water, aggregate and binder;
- directing the mixture through an extrusion zone at an elevated pressure to form a continuous unformed extrudate;
- directing the extrudate directly or indirectly from the extrusion zone to a transition zone and through the transition zone, said transition zone having a die chamber;
- selectively vibrating the die chamber without vibration of the extrusion zone;
- and
- directing the second mixture from the transition zone to a die and through the die to form an extruded cement-based article,
- wherein the die chamber is isolated from the extrusion zone and the die such that the extrusion zone and the die are substantially isolated from the vibration applied to the die chamber.
A process of forming an extruded cement-based article, comprising the steps of:
- directing a cement-based feed mixture through an extruder at an elevated pressure, wherein the extruder comprises an extrusion conduit and means for propelling the feed mixture through the extrusion conduit to provide an unformed continuous extrudate;
- directing the unformed continuous extrudate to a die chamber having an internal diameter that varies along its length, the die chamber further having a first opening operably connecting the extrusion conduit to the die chamber and a second opening operably connecting said die chamber to a die, and inwardly extending walls such that the internal diameter of said die chamber is larger proximate the first opening than the internal diameter of said die chamber proximate the second opening;
- and
- selectively vibrating said die chamber to provide substantial movement of said die chamber, said movement being in a direction substantially perpendicular to the direction of said unformed continuous extrudate, without providing substantial movement to the extrusion conduit;
- directing said unformed continuous extrudate through the selectively vibrating die chamber;
- and directing said unformed continuous extrudate through a final die to provide a formed extruded article,
- wherein the first opening operably connecting the die chamber to the extrusion conduit and the second opening operably connecting the die chamber to the die substantially isolate the extrusion conduit and the die from the vibration applied to the die chamber.
A process for forming an extruded, cement-based article, comprising:
- mixing a cement-based feed mixture including water, binder and aggregate;
- densifying the feed mixture in a vacuum zone, where the pressure within the vacuum zone is less than atmospheric pressure;
- extruding the densified material through an extrusion apparatus, a die chamber, and a die;
- and
- selectively vibrating the die chamber without substantially vibrating the extrusion apparatus and the die to form an extruded cement-based article,
- wherein the extrusion apparatus and the die is isolated from the die chamber such that vibrating the die chamber does not substantially vibrate the extrusion apparatus and the die, and the feed mixture is shredded after being mixed and before being fully densified.
A process for forming an extruded cement-based article, comprising:
- mixing together a cement-based feed mixture including water, binder and aggregate;
- densifying the feed mixture to form a densified cement-based material;
- extruding the densified material through an extrusion apparatus, a die chamber, and a die to form an extruded cement-based article;
- and
- selectively vibrating the die chamber,
- wherein the extrusion apparatus and the die are isolated from the die chamber such that the vibration applied to the die chamber is not substantially transferred to the extrusion apparatus and the die, and
- the process includes the steps of (a) measuring a thickness of said feed mixture during mixing, (b) comparing the measured thickness of said feed mixture with a reference value;
- and (c) adding water to said feed mixture in response to the comparison between said measured thickness and the reference value.
A process of forming an extruded cement-based article, comprising the steps of:
- forming a cement-based feed mixture comprising water, aggregate and binder;
- directing said feed mixture through a pretreatment zone with an entry section and an exit section in which flow of said feed mixture is restricted in an amount sufficient to increase a density of the said mixture and decrease a volume flow rate of said feed mixture, the pretreatment zone having a tortuous flow path extending between the entry and exit sections thereof that said feed mixture follows as it is directed through said pretreatment zone, said tortuous flow path applying a resistance force to said feed mixture;
- directing said feed mixture to a vacuum zone, wherein sufficient vacuum is maintained in the vacuum zone to remove entrained air from said feed mixture, said resistance forces applied to said feed mixture at least partially resisting suction forces imposed on said feed mixture by said vacuum zone;
- holding said feed mixture in said vacuum zone for a time sufficient to form a densified feed mixture;
- directing the densified feed mixture trough an extruder, a die chamber adjacent to the extruder, and a final die adjacent to the die chamber at an elevated pressure to provide an extruded, cement-based article;
- and
- vibrating the die chamber while substantially isolating the extruder and the final die from the vibrations applied to the die chamber.
An apparatus for forming an extruded cement-based article, comprising:
- a vacuum section configured to receive a feed mixture comprising an aggregate, a binder, and water, wherein a preselected level of vacuum is maintained in an amount sufficient to remove a preselected amount of entrained air and excess water from said feed mixture and thereby provide a densified vacuum-treated mixture of a desired density;
- and,
- an extrusion section for providing an extruded cement-based article, operably connected to said vacuum section, and including an extruder for receiving said densified vacuum-treated mixture from said vacuum section, a final die, and a die chamber interposed between the extruder and the final die and configured to be vibrated, wherein the die chamber is isolated from the extruder and the final die to prevent transferring a substantial amount of the vibrations to the extruder and the final die.
An apparatus for providing a formed, extruded cement-based article from a cement-based feed mixture, comprising:
- an extrusion conduit configured to receive the feed mixture;
- a die chamber for directly or indirectly receiving the feed mixture, the die chamber having an interior passage extending for a length of said die chamber, said die chamber having a first opening operably connecting the extrusion conduit to the die chamber interior passage, a second opening operably connecting said die chamber interior passage to a die, said die chamber interior passage having a cross-section that varies in dimension along its length such that said die chamber interior passage cross-section is larger proximate the first opening than proximate the second opening;
- a vibrator for selectively vibrating the die chamber to apply vibration to said die chamber, with substantial isolation of said extrusion conduit from the vibration;
- a final die operably connected to the die chamber for providing the formed, extruded cement-based article;
- and,
- said die chamber being interposed between said extrusion conduit and said final die, said die chamber further being isolated from abutting contact with said extrusion conduit and final die by flexible members interposed between said die chamber and said extrusion conduit and final die, whereby said substantial vibration applied to said die chamber is substantially not transferred to said extrusion conduit and said final die, said vibration facilitating passage of said feed mixture through said die chamber.
Dependencies are inferred from the claim text.