Method and apparatus for reducing the thickness of a skin formed on a slab of polyurethane foam
AssigneeFoamex L.P.
InventorsBruce W. Peterson, Theodore J. Bartsch
Life of this patent
Estimating the term…
Abstract
Methods and apparatus for eliminating or reducing a surface skin when producing a flexible polyurethane foam slab are disclosed. The top surface of the chemically reactive polyurethane foaming mixture is heated during and/or after the foaming mixture expands. The heating preferably is conducted so as to prevent a significant temperature gradient from forming between the internal temperature of the foaming mixture and the top surface of that mixture. Preferably, heat is applied so as to heat from the top surface of the foaming mixture in an escalating fashion to higher temperatures as the foam is conveyed along a conveying path away from the foaming mixture dispensing device.
Claims19
A method for reducing or eliminating a surface skin when producing a flexible polyurethane foam slab, comprising the steps of:
- (a) feeding a chemically reactive polyurethane foaming mixture into a region in which foaming expansion occurs wherein the chemically reactive polyurethane foaming mixture defines an internal temperature and defines a temperature at its top surface during its foaming expansion;
- and
- (b) heating the top surface of the polyurethane foaming mixture to a temperature in the range of about 230 to 260° F. (110 to 128° C.) for at least a part of the time during which the mixture expands to form the polyurethane foam slab.
An apparatus for producing a skinless or low skin flexible polyurethane foam slab, comprising:
- a dispensing device into which a chemically reactive polyurethane foaming mixture is introduced;
- a fall plate onto which the chemically reactive polyurethane foaming mixture is fed from the dispensing device;
- a conveyor for conveying the expanding foam away from the fall plate, said conveyor and fall plate together defining a conveying path along which the chemically reactive polyurethane foaming mixture is conveyed as it expands, wherein the chemically reactive polyurethane foaming mixture defines an internal temperature and defines a temperature at its top surface during its foaming expansion;
- and
- a heating source for heating at least a portion of a top surface of the chemically reactive polyurethane foaming mixture as the foaming mixture is conveyed along the conveying path, said heating source being mounted for tilting movement with relation to the conveying path.
Dependencies are inferred from the claim text.