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US 2023/0295871 A1Published application
Displacement dewatering a web using compressed gas
OwnerDavid Beckinventor
Life of this patent
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OwnerDavid Beckinventor
Estimating the term…
Apparatus, methods, and fabrics for dewatering a nascent paper web, carried in a web sandwich, in a dewatering section of a papermaking machine. Water is driven from the web by a combination of mechanical pressure and compressed air, both typically applied in a nip. The mechanical pressure and air pressure can be applied in the same nip, or in separate nips, where the mechanical pressure is applied upstream, in the papermaking machine, from the air pressure application. The mechanical pressure can be lower than pressures used in conventional press sections of known papermaking machines. Air pressure is that pressure which can be contained in a seal section between the web sandwich and the structure supplying the air. Fabrics supporting the nascent paper web through the air dewatering station have limited lateral air flow under compressed air conditions, whereby air flows generally perpendicularly through the web being dewatered.
A method for removing water from a nascent paper web in a papermaking machine in the process of fabricating a finished paper product, the nascent paper web comprising papermaking fibers and water, and having first and second opposing web surfaces which extend between first and second opposing edges of such nascent paper web, the nascent paper web having a generally continuous length, and a width, a first carrier fabric being disposed on the first surface of the nascent paper web and a second carrier fabric being disposed on the second opposing surface of the nascent paper web, the first and second carrier fabrics and the nascent paper web collectively defining a web sandwich, the web sandwich having first and second opposing sandwich surfaces, and a web machine direction corresponding with a machine direction of the papermaking machine, and a web cross machine direction, the web sandwich moving in the machine direction of the papermaking machine, the method comprising:
Apparatus for removing water from a nascent paper web in a papermaking machine in the process of fabricating a finished paper product, the nascent paper web comprising papermaking fibers and water, and having first and second opposing web surfaces which extend between first and second opposing edges of such nascent paper web, the nascent paper web having a generally continuous length, and a width, a first carrier fabric being disposed on the first surface of the nascent paper web and a second carrier fabric being disposed on the second opposing surface of the nascent paper web, a web sandwich comprising said first and second carrier fabrics and said nascent paper web, said web sandwich having first and second opposing sandwich surfaces, and a web machine direction corresponding with a machine direction of the papermaking machine, and a web cross machine direction, the web sandwich moving in the machine direction of the papermaking machine, said apparatus comprising:
Apparatus as in claim 63 wherein said perforated membrane is a first layer or sub-layer, and the respective said carrier fabric further comprises a second layer or sub-layer.
A papermaking fabric having lateral leakage, using the “DB Lateral Air Flow Test”, of no more than 8 cubic feet per minute, optionally no more than 6 cubic feet per minute, optionally no more than 3 cubic feet per minute, optionally no more than 2 cubic feet per minute.
Dependencies are inferred from the claim text.