EP 0824159 A3 19980401 -
Publication
Application
Priority
DE 19632509 A 19960813
Abstract (en)
[origin: EP0824159A2] In a process for making a web of fibrous material (especially paper), the suspension of fibrous material (stock) is passed through two dewatering units of a twin wire former, and the dewatering performance of the first dewatering unit is controlled in such a way that the water quantity removed per unit time in the second dewatering unit is held at an at least approximately adjustable rate. Also claimed is a twin wire former having a first dewatering section with an adjustable dewatering performance, and a second which is fitted with a device which measures the amount of water being removed by it. Preferably the quantity of water removed per unit time in the second dewatering unit is measured, and the measurement is fed to a control device (66) in which it is compared with a set point value. In the event of a deviation, the control device adjusts the dewatering performance of the first unit so that of the second unit is restored to approximately the set point value. The first dewatering unit is subjected to a suction which is varied to obtain the required dewatering performance. Both sieve belts (11,12) in the first unit may be passed over at least one curved surface to which the suction device is connected. In the second unit, one sieve belt is passed over fixed rails, whilst the other is subjected to pressure from flexible rails. The controller has input channels for the measured value and the set point, and an output channel for a control signal which effects a change in the performance of the first dewatering unit.
IPC 1-7
IPC 8 full level
CPC (source: EP)
D21F 9/003 (2013.01); D21G 9/0027 (2013.01)
Citation (search report)
- [DY] WO 9102842 A1 19910307 - VOITH GMBH J M [DE]
- [Y] DE 3740577 A1 19880616 - BARTELMUSS HEINRICH ING [AT]
Designated contracting state (EPC)
AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
DOCDB simple family (publication)
EP 0824159 A2 19980218; EP 0824159 A3 19980401; CA 2212929 A1 19980213; DE 19632509 A1 19980305
DOCDB simple family (application)
EP 97111795 A 19970711; CA 2212929 A 19970813; DE 19632509 A 19960813