D
SECTION D — TEXTILES AND PAPER
  
PAPER
 D21
PAPER-MAKING; PRODUCTION OF CELLULOSE
 D21D
TREATMENT OF THE DIGESTED MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE; PROCESSES FOR ADDING SUBSTANCES TO THE FORMED WEB ON THE PAPER-MAKING MACHINE
 D21D 1/00
Methods of beating or refining; Beaters of the Hollander type (knotter screens D21F)
 D21D 1/02
·  Methods of beating; Beaters of the Hollander type
 D21D 1/04
·  ·  Beater rolls and bars
 D21D 1/06
·  ·  Bed plates
 D21D 1/08
·  ·  Beaters with means for driving the pulp quickly
 D21D 1/10
·  ·  Beaters with means for regulating the pressure between the beater roll and the bed plate
 D21D 1/12
·  ·  Beaters with means for continuous pulp discharge
 D21D 1/14
·  ·  Beaters with one beater roll and with vertical stuff circulation canal
 D21D 1/16
·  ·  Beaters with means for returning the pulp over the head of the beater roll
 D21D 1/18
·  ·  Beaters with two or more beater rolls
 D21D 1/20
·  Methods of refining
 D21D 1/22
·  ·  Jordans
 D21D 1/24
·  ·  ·  Jordan rolls
 D21D 1/26
·  ·  ·  Jordan bed plates
 D21D 1/28
·  ·  Ball or rod mills
 D21D 1/30
·  ·  Disc mills
 D21D 1/32
·  ·  Hammer mills
 D21D 1/34
·  ·  Other mills or refiners
 D21D 1/36
·  ·  ·  with vertical shaft
 D21D 1/38
·  ·  ·  with horizontal shaft
 D21D 1/40
·  ·  Washing the fibres
 D21D 3/00
Processes for adding substances to the wet pulp or to the formed web on the paper-making machine, e.g. sizing, impregnating (bleaching cellulose D21C 9/10; paper or cardboard produced by adding substances to the pulp or to the formed web on the paper-making machines D21H 3/00)
 D21D 5/00
Purification of the pulp suspension by mechanical means; Apparatus therefor (centrifuges, cyclones B04)
 D21D 5/02
·  Straining or screening the pulp
 D21D 5/04
·  ·  Flat screens
 D21D 5/06
·  ·  Rotary screen-drums
 D21D 5/08
·  ·  ·  combined with a rocking movement
 D21D 5/10
·  ·  ·  ·  of the tank
 D21D 5/12
·  ·  ·  ·  of the screen
 D21D 5/14
·  ·  ·  ·  of the tank and the screen
 D21D 5/16
·  ·  Cylinders and plates for screens
 D21D 5/18
·  with the aid of centrifugal force
 D21D 5/20
·  ·  in apparatus with a horizontal axis
 D21D 5/22
·  ·  in apparatus with a vertical axis
 D21D 5/24
·  ·  in cyclones
 D21D 5/26
·  De-aeration of paper stock
 D21D 5/28
·  Tanks for storing or agitating pulp