DE10005694A1 - Process for the production of a finished stock suspension and constant part of a paper or board machine - Google Patents

Abstract

The invention relates to a manufacturing process for stock suspension by admixing newly prepared fiber and filler to a white water circuit and a constant part of a paper machine with a mixing tube (30). DOLLAR A The invention is characterized in that a large number of individual injections (1-6) into the mixing tube (30) are used to produce a final material suspension, the free flow cross sections in the mixing tube (30) and in the individual injections (1- 6) are designed so that the flow rate in the mixing tube (30) is greater than 0.2 m / s, preferably greater than 0.45 m / s and the flow rates of the supplied suspension in a nozzle v¶D¶ and the main flow around the nozzle v¶U¶ form a ratio of v¶D¶ / v¶U¶ between 3-15.

Description

The invention relates to a method for producing a finished stock suspension for the production of a paper or Cardboard web by adding newly processed fiber and Filler with possibly different properties and / or composition to form a white water cycle, preferably the white water I cycle, in the constant part a paper or board machine. In addition, the Invention the constant part of a paper or Board machine.

A similar process for blending thick matter into one existing white water cycle and a similar constant Part is for example from the published patent application DE 32 44 142 A1 (≈ US 4,477,313). Here is one in several subdivided white water cycle previously prepared Thick matter via a mixing pump the white water supplied added again and the resulting material suspension one Headbox fed. This thick matter consists in known way from fiber and fillers that according to the specifications of the paper maker before feeding processed in the white water cycle, i.e. in predetermined mixing ratios in a mixing chest is merged and mixed.  

In the known paper or cardboard machines in the constant part of the paper or cardboard machine a considerable amount of mechanical effort is required to process such a thick material. In Fig. 1 (composed of Figs. 1a and 1b) there is shown a schematic representation of this stock preparation in the constant part of the paper or board machine, which provided the fibrous materials and fillers open mixing vat and an open machine chest for mixing the individual components in which the uniform mixing of the individual components takes place.

Such a configuration of the constant part of a paper or board machine, especially the stock preparation very complex and requires a considerable amount of machinery and Space requirements, which means significant investment and Operating costs arise.

It is therefore an object of the invention to provide a method describe the space required for the Thick matter preparation and mixing with the white water can be significantly reduced, but at the same time the quality and uniformity of mixing the individual stock suspension components versus one At least a method using mixed paper should be equivalent. It is also a task for you to specify a constant part of a paper or board machine, with which the inventive method is to be carried out.

The object of the invention is achieved by the features of independent claims solved.  

The inventor has recognized that it is possible to use the individual Components of the stock suspension of a paper or Cardboard machine directly into a white water circuit feed in, to mix the individual components now no mixing chest is necessary, just a mixing tube is used, the main flow through a white water cycle is formed in which the new prepared fiber and fillers as individual components and without mixing them together beforehand. Here is crucial among which Speeds and speed ratios Mixing of the individual components takes place.

Accordingly, the inventor proposes a process for the production of a finished stock suspension for the production of a paper or cardboard web by admixing newly prepared fiber and filler with possibly different properties and / or composition to form a white water cycle, preferably the white water I cycle, in the constant part of a paper - or cardboard machine with at least the following process steps: leading a white water recirculating from the paper or cardboard machine, in particular white water I, into an optionally angled mixing tube ( 30 ) with a main flow direction and injection of a large number of, preferably newly prepared, individual components of the fiber and / or filler into the mixing tube ( 30 ), the flow rate in the mixing tube ( 5 ) being greater than 0.2 m / s, preferably greater than 0.45 m / s and the flow rates of the supplied suspension in a nozzle v _D and the house pt flow of the environment around the nozzle v _{U form} a ratio of v _D / v _U between 3-15.

According to the invention, this method does not find a first one Premix the individual components into a thick material instead of the individual components of the fiber and fillers directly into a white water Mixing tube injected, and the mixing of each Components takes place directly in the white water itself, so that this then as a finished stock suspension Manufacturing process can be supplied.

An advantageous embodiment of the invention The procedure is that at least part of the remaining recirculating suspension from the paper or Cardboard machine production is mixed in the mixing tube, whereby it is particularly advantageous if the rest recirculating suspensions in the mixing tube downstream of the Injection of individual components can be supplied. Through this Practically all mixed chests that were previously in the measure Area of a paper or board machine in the constant part were necessary to be saved. This reduces also the circulated volume of white water is significant, since at least the volume of the previous blended paper ceases to exist that the changeover time between different Types of paper can be significantly shortened.

According to the inventive concept, a is preferably angled mixing tube used because of the bend of the mixing tube additional secondary currents in the mixing tube arise that the mixing process in its uniformity promote significantly.

According to a broader idea of the invention suggested that the individual components before bending of the mixing tube are supplied. Can continue  advantageous after the remaining recirculating suspensions be fed to the bend of the mixing tube.

By dividing the supply of fiber and / or Fillers or the remaining recirculating Suspensions in the mixing tube will be particularly good and uniform mixing of the individual components reached.

According to the requirements for the uniformity of the Stock suspension is further proposed according to the invention, that the relative quantitative ratio of the individual components with Fibers is regulated to each other. The type of scheme can according to the known methods, either via a speed-controlled pump or via a valve throttling of the Throughput of a pump.

It is also suggested that the relative Quantity ratio between the total amount of Individual components with fibers and the total amount of Individual components with filler is regulated. For this Regulation of the proportions can after the exit of the Mixing tube concentration measurements of each Components, i.e. the substances to be regulated, take place and the measurement result in the control loop as a controlled variable be used.

To avoid unwanted fiber wiping or other unwanted particles in the stock suspension can between sorting and / or the mixing tube and the headbox Sighting of the stock suspension take place.  

According to the inventive concept, a constant part of a paper or board machine is proposed, which is characterized in that a mixing tube with a main supply for white water recirculating from the paper machine, preferably white water I, is provided and this forms a main flow in the mixing tube, further that a A large number of individual injections into the main flow are provided for all the individual components required to produce a final stock suspension, the free flow cross sections in the mixing tube ( 30 ) and in the individual injections ( 1-6 ) being designed such that the flow velocity in the mixing tube ( 30 ) is greater than 0.2 m / s, preferably greater than 0.45 m / s and the flow velocities of the supplied suspension in a nozzle v _D and the main flow of the environment around the nozzle v _{U is} a ratio of v _D / v _U between 3-15 form.

An advantageous embodiment of the mixing tube provides that the injection of the individual components in the direction of Main flow are arranged one after the other.

The mixing tube can advantageously be angled, in order to mix the to improve individual components.

Furthermore, an injection for accept material from a deculator and / or from a vertical classifier 2 can additionally be carried out. Level and / or other material recirculation can be provided.

With regard to the arrangement of the injections, it can also be advantageous if the injection of the individual components before the injection of accept material from a deculator and / or from a vertical classifier 2 . Stage and / or other material recirculation is arranged. It is also advantageous to inject the individual components before angling the mixing tube and to inject accept material from a deculator and / or from a vertical classifier 2 . Stage and / or other material recirculation is arranged after the bend of the mixing tube.

Fresh fiber materials (= TMP) can be used as individual components and / or waste paper (= DIP) and / or committee from the Paper machine and / or filter backing and / or paint and / or chemicals and / or filler are used.

Additional features and advantages of the invention result from the following description of a preferred Embodiment with reference to the drawings.

The invention will now be described with reference to the drawings are explained. In detail:

Figs. 1a and 1b: Known embodiments the stock preparation in a paper and board machine;

Fig. 2: Exemplary embodiments of a stock preparation according to the invention in the constant part of a paper or board machine;

Fig. 3: Detailed representation of an injection in the mixing tube.

Fig. 1 is composed of FIGS. 1a and 1b and shows the constant part of a paper or board machine, according to the prior art, with the middle part of the overall figure can be seen on the two FIGS. 1a and 1b.

The FIG. 1 thus shows the known in the prior art constant part of a paper or cardboard machine for the preparation of pulp suspension for feeding to a sectionally consistency can and volume-controlled headbox 17th At the beginning of the constant part, freshly prepared individual components of the thick matter are introduced one after the other into a mixing chest 7 via lines 1 to 6 . The individual components are fresh fibrous material (TMP = Thermo mechanical pulp) via line 1 , processed waste paper (DIP = deinked paper) via line 2 , processed scrap from the paper machine via line 3 , filter residues via line 4 , color and / or Chemicals via line 5 and filler via line 6 .

In the mixing chest 7 , the individual components are mixed uniformly and the desired thick matter is processed. According to the prior art, the individual feed lines 1 to 6 have control mechanisms which set the quantitative ratios of the individual components in the desired manner in order to achieve the correct final composition of the thick matter.

The thick matter produced in the mixing chest 7 is then passed into the machine chest 8 , from where it is fed to the white water I tank 9 .

In the white water I container 9 , the thick matter is then diluted to the desired concentration and then the stock suspension is fed via line 13 to the deculator cleaner system, in which the newly prepared stock suspension is vented. From Deculator cleaner system, the suspension is supplied via the supply conduit 14 again via a vertical separator for cleaning and brought the stock material through the line 26 to the headbox 17th

A stock suspension with a somewhat lower concentration is likewise fed from the deculator cleaner system via the feed line 15 to a further vertical separator 12 and from there via the feed line 16 to the headbox 17 . In a known manner, the two differently concentrated stock suspensions are sectionally regulated in the headbox 17 , mixed and transferred to the wet end 18 . To control the entire system, a measuring frame 28 is provided in a known manner at the end of the paper or board machine, which collects information about the mass-transverse profile, the mass-longitudinal profile and the ash content of the paper web produced and is available for regulating the composition of the white water stands.

All in all, the constant part of the paper machine, especially the material center 29 with the feeds 1 to 5 , the mixing chest 7 , the machine chest 8 and the white water I container 9 requires a large amount of space and thus represents an enormous factor with regard to the investment and operating costs of the paper machine represents.

According to the invention, attempts are now being made to reduce these costs by merging the individual parts into a single mixing element, but at the same time the quality of the resulting material suspension is to be retained. A corresponding method and a correspondingly equipped constant part of the paper machine is shown in FIG. 2. Here, the entire area 48 shown in dashed lines from FIG. 1 is concentrated by using a mixing tube 30 .

In the mixing pipe 30, the recycled white water is introduced I 38 and guided in a main flow direction along the center line 47 of the mixing tube 30th

In the mixing tube 30 , the individual components TMP via the feed line 1 , DIP via the feed line 2 , rejects from the paper or board machine via the feed line 3 , filter waste via the feed line 4 , finally paint and chemicals via the feed line 5 and filler via the Supply line 6 supplied. The individual components are supplied here, for example, in the vertical section of the mixing tube 30 , before it is angled into the horizontal section.

It should be noted that it is within the scope of the invention is a free selection of the individual components to be fed to be taken, choosing the individual components regarding their composition and the relative Quantity relationship to each other of the paper to be produced or carton is dependent. For example it is also possible on the waste paper portion or the TMP portion to waive when a corresponding end product is manufactured shall be.

Subsequent to the angling of the mixing tube, the supply takes place via a nozzle 35 of accept material 36 from the deculator and accept material 37 from the vertical classifier 2 . Step. Due to the bending of the mixing tube, secondary currents are generated, which bring about a particularly good mixing of the individual components of the suspension. Subsequent to the mixing tube 30 , the stock suspension is fed via a feed pump 39 to a downstream classifier 44 and the accept material 45 from the classifier is fed to the deculator cleaner system, while the classifier return 46 is fed back to the processing unit.

A control system 40 (usually referred to as QCS = Quality Control System) is used to control the system shown, which receives the necessary information about the fiber concentration via the measuring sensors 49 and the measuring line 41 . Likewise, the filler concentration of the finished stock suspension is measured via the sensor 50 and fed to the control system 40 via the measuring line 42 . The control system 40 has a predetermined quantitative ratio for the components TMP, DIP, rejects and filter waste, so that these components are always supplied in the predetermined quantitative ratio, the total amount of these fibrous materials being increased via the control system 40 or vice versa if the concentration of fibrous materials is too low can be.

In addition, the fogging system 40 controls the addition of paint and chemicals via the control line 43.5 , which can optionally be divided again in order to determine the mixture of the individual chemicals.

Finally, the control system 40 also regulates the amount of filler supplied via the control line 43.6 , corresponding to the concentration of filler in the finished stock suspension measured by the measuring sensor 50 .

To clarify the flow conditions in the area of an injection in the mixing tube, this situation is shown again in detail in FIG. 3. Here it is shown how the main flow in the mixing tube 30 in the immediate vicinity of the nozzle 51 of the injection of a concentrated single component of the pulp suspension at a flow rate V _H flows around the nozzle 51, which exits the nozzle 51, the single component with the flow rate v _D and then with the Main flow is mixed. The optimal mixing takes place when the free flow cross sections of the mixing tube 30 and the respective nozzle 51 are designed so that the flow velocity v _H in the mixing tube ( 30 ) is greater than 0.2 m / s, preferably greater than 0.45 m / s and the flow velocities of the supplied suspension in a nozzle v _D and the main flow of the surroundings around the nozzle v _{U form} a ratio of v _D / v _U between 3-15.

By this inventive method and Execution of the constant part according to the invention will now possible to use the entire mixing area in the constant part of the Simplify paper or board machine considerably and in particular to greatly reduce the space required. As a positive side effect, this also means that the amount of suspensions in circulation is significant reduce, which means a much faster changeover of the Paper machine on new types of paper is possible.

In addition, it is pointed out that the characteristics of the Invention not only in the specified combination, but also in other combinations or alone can be used without departing from the scope of the invention.  

Reference list

1

TMP feed (mechanical pulp = fresh fibers)

2

Feed DIP (deinked paper = processed waste paper)

3rd

Feeding scrap from the paper machine

4

Feed back filter

5

Feeding paint / chemicals

6

Feed filler

7

Mixing chest

8th

Machine chest

9

White water I container

10th

Deculator cleaner system

11

Vertical classifier

12th

Vertical classifier

13

Supply line from the white water I tank to the Deculator Cleaner System

14

Supply line from the deculator cleaner system to the vertical classifier

15

Supply line from the vertical classifier

14

to the headbox

16

Supply line from the vertical classifier

12th

to the headbox

17th

17th

Sectionally controlled headbox (jet headbox modules)

18th

Screen sections

19th

Return of the white water I to the white water I tank

20th

White water II return

21

Retention agent regulation

22

Retention agent container

23

Filler control

24th

Filler reservoir

25th

Supply line from the retention agent container

22

to the Vertical classifier

11

26

Supply line from the vertical classifier

11

to the headbox

17th

27

Sorting

28

Measuring frame

29

Substance center

30th

angled mixing tube

31

speed-controlled pump

32

Flow meter

33

Throttle valve

34

Pump (constant speed)

35

Injection

36

Acceptable material from deculator

37

Acceptable material from vertical classifier

2

, step

38

White water I

39

Feed pump

40

Control system (quality control system)

41

Measuring line for fiber concentration

42

Measuring line for filler concentration

43.1

to

43.6

Control lines

44

Classifier

45

Acceptable material supply to the Deculator Cleaner system

46

Classifier return

47

Center line

48

Area

49

Sensor

50

Sensor
FFIC flow ratio display controller
FI flow sensor
FT flow transmitter
HIC manual adjustment
LIA level indicator alarm
LIC level indicator controller
LT level transmitter
PI pressure sensor
PT pressure transmitter
QIC quality (ash, fiber density) display regulation
QT quality (ash, fiber density) sensor
SIC speed display control
v _D

Flow rate in a nozzle
v _H

Main flow around a nozzle

Claims (16)

1. Process for the production of a finished stock suspension for the production of a paper or cardboard web by admixing newly processed fiber and filler with possibly different properties and / or composition to form a white water circuit, preferably the white water I circuit, in the constant part of a paper or cardboard machine with at least the following procedural steps:

• 1.1 1.1 guiding a white water recirculating from the paper or board machine, in particular white water I, in an optionally angled mixing tube ( 30 ) with a main flow direction and
• 2. 1.2 injection of a plurality of, preferably newly prepared, individual components of the fiber and / or filler into the mixing tube ( 30 ), wherein
• 3. 1.3 the flow velocity in the mixing tube ( 30 ) is greater than 0.2 m / s, preferably greater than 0.45 m / s and
• 4. 1.4 the flow velocities of the supplied suspension in a nozzle v _D and the main flow of the surroundings around the nozzle v _{U form} a ratio of v _D / v _U between 3-15.

2. The method according to claim 1, characterized in that at least part of the remaining recirculating suspensions ( 36 , 37 ) are mixed in the mixing tube ( 30 ). 3. The method according to claim 2, characterized in that the remaining recirculating suspensions ( 36 , 37 ) in the mixing tube ( 30 ) are fed downstream of the injection of the individual components. 4. The method according to any one of claims 1 to 3, characterized in that the individual components are supplied before the bending of the mixing tube ( 30 ). 5. The method according to any one of claims 2 to 4, characterized in that the remaining recirculating suspensions ( 36 , 37 ) are fed after the bending of the mixing tube ( 30 ). 6. The method according to any one of claims 1 to 5, characterized characterized in that the relative ratio of the Individual components with fibers are regulated to each other. 7. The method according to any one of claims 1 to 6, characterized characterized in that the relative quantitative ratio between the total amount of individual components with Fibers and the total amount of individual components Filler is regulated. 8. The method according to any one of claims 6 to 7, characterized in that the regulation of the quantitative ratios takes place via a concentration measurement of the substances to be controlled behind the outlet of the mixing tube ( 30 ). 9. The method according to any one of claims 1 to 8, characterized in that between the mixing tube ( 30 ) and the headbox ( 17 ) there is a sorting and / or screening of the stock suspension. 10. Constant part of a paper or board machine, characterized in that a mixing tube ( 30 ) with a main feed for from the paper or board machine recirculating white water, preferably white water I ( 38 ), is provided and this is a main flow in the mixing tube ( 30 ) forms, further that a large number of individual injections ( 1-6 ) are provided in the main flow for all the individual components required to produce a final stock suspension, the free flow cross sections in the mixing tube ( 30 ) and in the individual injections ( 1-6 ) being designed in this way are that the flow velocity in the mixing tube ( 30 ) is greater than 0.2 m / s, preferably greater than 0.45 m / s and the flow velocities of the supplied suspension in a nozzle v _D and the main flow of the environment around the nozzle v _{U are} a ratio of v _D / v _U between 3-15. 11. Constant part according to claim 10, characterized in that the injection ( 1-6 ) of the individual components are arranged one after the other seen in the direction of the main flow. 12. Constant part according to one of claims 10 to 11, characterized in that the mixing tube ( 30 ) is angled. 13. Constant part according to one of claims 10 to 12, characterized in that in addition an injection ( 35 ) for accept material from a deculator ( 36 ) and / or from a vertical light 2 . Stage ( 37 ) and / or other acceptances is provided. 14. Constant part according to claim 13, characterized in that the injection ( 1-6 ) of the individual components before the injection ( 35 ) of accept from a deculator ( 36 ) and / or from a vertical classifier 2 . Stage ( 37 ) and / or other acceptances is arranged. 15. Constant part according to claim 14, characterized in that the injection ( 1-6 ) of the individual components prior to the angling of the mixing tube ( 30 ) and the injection ( 35 ) of accept from a deculator ( 36 ) and / or from a vertical classifier 2nd ( 37 ) stage and / or other material recirculation after the bend of the mixing tube ( 30 ) is arranged. 16. Constant part according to one of claims 10 to 15, characterized in that as individual components fresh fiber (TMP) and / or waste paper (DIP) and / or scrap from the paper machine and / or Filter backing and / or paint and / or chemicals and / or filler can be used.