Wet-End Manufacturing Process for Bitumen-Impregnated Fiberboard
AssigneeW. R. Meadows, Inc.
InventorTariq Mahmood Malik
Life of this patent
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Abstract
A process for manufacturing fiberboard by preparing a fiber slurry mixture including containing cellulose fibers and water then atomizing a liquid bituminous material, such as asphalt. The liquid bituminous material is atomized by mixing it with a pressurized gas, such as compressed air, forming a mist comprising droplets of bituminous material having a diameter between 20 microns and 50 microns. A water spray solidifies the bituminous material droplets thereby forming bituminous particles which fall into the fiber slurry within the spray chamber. From there the slurry is sheared, dewatered, and dried, forming a finished fiberboard.
Claims25
A process for manufacturing fiber board comprising the steps of:
- preparing a fiber slurry mixture by adding a material containing cellulose fibers to water and agitating the fiber slurry mixture;
- transferring the fiber slurry mixture to a spray chamber;
- heating a bituminous material to a temperature between 300 and 440 degrees F., wherein the bituminous material is in a liquid state;
- atomizing the liquid bituminous material within the spray chamber by mixing the liquid bituminous material with a pressurized gas, forming a mist comprising droplets of bituminous material having a diameter between 20 microns and 50 microns;
- solidifying the bituminous material droplets by spraying water into the mist thereby forming bituminous particles which fall into the fiber slurry within the spray chamber;
- shearing the slurry containing cellulose fibers and bituminous particles;
- dewatering the slurry containing cellulose fibers and bituminous particles, leaving a wet mat containing fibers and bituminous material;
- drying the wet mat thereby forming a fiber board;
- and
- optionally, further including the step of applying a coating to both major sides of the dried fiberboard.
A process for producing bituminous particles by atomizing a molten bituminous material comprising the steps of:
- heating a bituminous material to a temperature such that the bituminous material is in a liquid state;
- passing the liquid bituminous material through a nozzle, the nozzle having a liquid passage and a plurality of gas passages, and an atomization chamber, wherein the liquid bituminous material and a pressurized gas provided through the plurality of gas passages are mixed together within the atomization chamber forming a mist of liquid bitumen droplets;
- solidifying the liquid bitumen droplets by spraying with water;
- wherein the bituminous material is heated to a temperature between 300 and 440 degrees F.;
- and
- wherein the bituminous material is atomized by mixing with a gas having a pressure of between approximately 10 psi and 50 psi;
- alternatively, wherein the bituminous material is atomized by mixing with a gas having a pressure of between approximately 20 psi and 40 psi.
A process for manufacturing fiber board comprising the steps of:
- preparing a fiber slurry mixture by adding a material containing cellulose fibers to water and agitating the fiber slurry mixture,
- the material containing cellulose fibers being selected from the group consisting of wood pulp, sugar cane, switch grass, straw, and recycled paper pulp, and wherein the solid content of the slurry is less than about 10% weight but greater than about 8% weight;
- heating a bituminous material to a temperature between 300 and 450 degrees F., wherein the bituminous material is in a liquid state;
- atomizing the liquid bituminous material within the spray chamber by mixing the liquid bituminous material with a gas,
- wherein the gas is supplied at a pressure between 20 psi and 40 psi, and
- wherein the gas is supplied at a temperature between 200 degrees F. and 300 degrees F.,
- producing a mist comprising droplets of bituminous material having a diameter between 20 microns and 50 microns;
- solidifying the bituminous material droplets by spraying water into the mist,
- the water having a temperature between 45 degrees F. and 55 degrees F., thereby forming bituminous particles having a diameter between 20 microns and 50 microns which fall into the fiber slurry within the spray chamber, wherein the asphalt content of the slurry is less than about 30% weight but greater than about 10% weight;
- shearing the slurry containing cellulose fibers and bituminous particles;
- dewatering the slurry containing cellulose fibers and bituminous particles, leaving a wet mat containing fibers and bituminous material;
- and
- drying the wet mat thereby forming a fiber board, the finished fiber board having a total bitumen content between about 10% and 40% by weight.
A process for producing bituminous particles from a molten bituminous material comprising the steps of:
- heating a bituminous material to a temperature such that the bituminous material is in a liquid state;
- passing the liquid bituminous material through a liquid passage for receiving an adjustable flow of liquid bituminous material thereby forming liquid bitumen droplets;
- and
- allowing the liquid bitumen droplets to enter a slurry and solidify in the slurry, wherein the slurry comprises a material containing cellulose fibers and water.
Dependencies are inferred from the claim text.