CPC Definition - Subclass D21G

Last Updated Version: 2016.11
CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES (winders or rewinders for finished products, means for adjustment of wrinkles or lateral extensions B65H)
Definition statement

This place covers:

Calenders, smoothing apparatus.

Rolls for calenders, controlled deflection rolls, doctors, safety devices for paper machinery, damping devices, paper making control systems, devices for threading web tails through a paper machine.

Coating devices in combination with calenders or other sections in a paper machine.

References
Informative references

Attention is drawn to the following places, which may be of interest for search:

Rolls for rolling metal

B21B 27/00

Registering, tensioning, smoothing or guiding webs

B65H 23/00

Methods and devices for coating paper webs in general

D21H

Rolls in general

F16C 13/00

Special rules of classification

Subgroups and head groups.

If a document concerns embodiments which are covered by several subgroups dependent on a higher hierarchy group, the following rules apply:

the specific technical information relevant for some of the subgroups is classified in all said subgroups;

if relevant, the structural association (e.g. the combination) of the elements covered by the subgroups is classified in the head group;

analogously, if generic technical information common to all of the subgroups is disclosed and only schematic embodiments of the specific subgroup embodiments are represented, the documents is classified in the head group only.

Glossary of terms

In this place, the following terms or expressions are used with the meaning indicated:

Section

portion of a paper production machine effecting a certain process step, for example forming, pressing, drying, calendering, coating, ...;

Doctor

device or cleaning the surface of a band, cylinder or roll or for metering a coating substance on the surface of a web

Doctors
Definition statement

This place covers:

Doctor devices for paper machines in general.

References
Informative references

Attention is drawn to the following places, which may be of interest for search:

Application blades in general

B05C 11/04

Doctors for crêping

B31F 1/14

Doctors for printing machines

B41F 9/10

Doctors for coaters

D21H 23/34, D21H 25/10

Damping devices
Definition statement

This place covers:

Damping devices for paper machines, i.e. devices for applying moisture in form of water or steam.

References
Limiting references

This place does not cover:

Web conditioning devices arranged in calenders

D21G 1/0093

Damping devices for printing machines

B41F 7/24

Steam blow boxes arranged in the paper machine

D21F 7/008

Other accessories for paper-making machines
Definition statement

This place covers:

Devices that can be used e.g. for controlling or measuring parameters, not essential for the technical functioning of the machine; Control systems and methods; Coating devices in combination with paper machine sections;

{Paper-making control systems}
References
Informative references

Attention is drawn to the following places, which may be of interest for search:

Sensor rolls

G01L 5/00

Fault detection

G01N 21/89

Measuring paper sheets

G01N 33/34

{Apparatus for glaze-coating paper webs}
Definition statement

This place covers:

Coating processes using two rolls rotating at different speed.

Complete papermaking machines (i.e. at least two sections in combination) comprising a coating section in combination with other paper machine sections, e.g. calendering or drying section.

References
Informative references

Attention is drawn to the following places, which may be of interest for search:

Apparatus for coating paper webs in general

D21H 23/00