Method of and an arrangement for adding at least one additional stock component to an approach flow system of a fiber web machine

Patent metadata

Field	Value
Publication number	US-11459700-B2
Application number	US-202017127548-A
Country	US
Kind code	B2
Filing date	Dec 18, 2020
Priority date	Dec 20, 2019
Publication date	Oct 4, 2022
Grant date	Oct 4, 2022

Abstract

A method of and an arrangement for adding at least one additional stock component to an approach flow system (30) of a fiber web machine by mixing the at least one additional stock component to a fibrous stock such that the stock flow is equalized (50) and the at least one additional stock component is introduced to the stock flow by injection mixing (80).

First claim

The invention is:

1. A method of adding at least one additional stock component to a stock flow in an approach flow system of a fiber web machine headbox, wherein a fibrous stock is introduced by a headbox feed pump via a headbox screen, a headbox feed pipe and a chemical mixer to the headbox of a fiber web machine, the method comprises:
treating the stock flow by equalizing consistency differences prevailing in the stock flow downstream of the headbox screen to form an equalized but not dampened stock flow, and
after treating the stock flow to form the equalized but not dampened stock flow, mixing the at least one additional stock component with the already equalized but not dampened stock flow.

2. The method as recited in claim 1 , further comprising providing a stock flow equalizer to perform the step of the treating the stock flow by equalizing the consistency differences prevailing in the stock flow, wherein the stock flow equalizer is between the headbox screen and the chemical mixer at a distance from the chemical mixer.

3. The method as recited in claim 1 , further comprising using an injection mixing station to add the at least one additional stock component to the stock flow by using at least one of fresh pulp, recycled pulp, white water and fresh water as an injection liquid for the injection mixing station.

4. The method as recited in claim 1 , further comprising using an injection liquid to carry the at least one additional stock component into the equalized stock flow.

5. The method as recited in claim 1 , further comprising using an injection mixing station to add the at least one additional stock component to the stock flow, wherein the injection mixing station uses an injection liquid to carry the at least one additional stock component to the stock flow, and the injection liquid is stock from the headbox feed pipe take upstream or downstream of the stock flow equalizer and upstream of the injection mixing station.

6. The method as recited in claim 1 , wherein the at least one additional stock component is at least one of: a retention chemical, sizing agent, a starch, filler, paper dye or pigment, a micro-fibrillated cellulose, a nano-fibrillated cellulose, a bio-based fiber and a synthetic fiber.

7. A method comprising:
pumping a flow of stock of a suspension of fibers through a headbox pipe;
screening the flow of stock in a headbox screen connected to the headbox pipe;
equalizing consistency differences in the flow of stock downstream of the headbox screen and upstream of a headbox to form an equalized and turbulent flow of stock, wherein the equalizing consistency differences is performed without dampening the flow of stock;
after the step of equalizing consistency differences, mixing an additional stock component into the equalized and turbulent flow of stock upstream of the headbox and downstream in the flow of stock from the equalizing consistency differences, and
directing the equalized and turbulent flow of stock with the additional stock component through the headbox pipe and into the headbox.

8. The method of claim 7 wherein the equalizing of consistency differences is performed with a stock flow equalizer comprising a tube having an inside surface wetted by the flow of stock, wherein the inside surface has a diameter equal to an inner diameter of the headbox pipe, and the stock flow equalizer further comprises form parts arranged symmetrically around a circumference of the inside surface, wherein each of the form parts extends radially inward from the inside surface a distance in a range of 0.1 to 0.5 times an inner diameter of the headbox feed pipe.

9. The method of claim 8 , wherein the form parts each include a ramp extending downstream from the inside surface to an apex having a height 0.1 to 0.5 times the inner diameter of the headbox feed pipe.

10. The method of claim 9 , wherein each of the form parts has a downstream side parallel to a radial line and extending from the apex to the inside surface.

11. The method of claim 9 , wherein each of the form parts has a first triangular shape in a first cross section parallel to a flow direction through the tube of the equalizer and a second triangular shape in a second cross section perpendicular to the flow direction.

12. A method comprising:
screening the flow of stock in a headbox screen;
equalizing consistency differences in the flow of stock by creating turbulence in the flow of stock downstream of the headbox screen and upstream of a headbox, wherein the turbulence forms an equalized flow of stock, wherein the equalizing consistency differences is performed without dampening the flow of stock;
mixing an additional stock component into the equalized flow of stock upstream of the headbox and after the step of equalizing consistency differences, and
after the step of mixing the additional stock component, directing the equalized flow of stock with the additional stock component into the headbox.

13. The method of claim 12 , wherein the step of creating turbulence is performed without adding a stock component to the stock.

14. The method of claim 12 , wherein the stock flows through a headbox feed pipe from the headbox screen to the headbox, and step of equalizing consistency differences is performed in the headbox feed pipe a distance upstream of the step of mixing the additional stock component in a range of five to fifteen times a diameter of the headbox feed pipe.

15. The method of claim 12 , wherein the stock flows through a headbox feed pipe from the headbox screen to the headbox, and step of equalizing consistency differences is performed in the headbox feed pipe a distance upstream of the step of mixing the additional stock component at least one diameter of the headbox feed pipe.

Assignees

• Wetend Tech Oy
• Valmet Technologies Oy

Inventors

• Ketolainen Antti
• Matula Jouni
• Piippola Leif

Classifications

• D21F1/82

  adding fibre agglomeration compositions · CPC title

• D21F1/0018

  Devices for dispensing fibres in a fluid · CPC title

• D21F1/024

  Details of the feed chamber · CPC title

• D21H23/20

  Apparatus therefor · CPC title

• D21F1/08 Primary

  Regulating consistency · CPC title