DE102018105384A1 - Apparatus and method for producing a fiber foam - Google Patents

Abstract

An apparatus for producing a fiber foam comprises: a container (110), a rotatably mounted stirring tool (120) and at least two compartments (130). The container (110) defines an axially extending interior (115) for receiving a liquid medium, the interior (115) including a first axial portion (111) and a second axial portion (112). The rotatably mounted stirring tool (120) has an axis of rotation (R) parallel to the axial extent of the inner space (115). The at least two compartments (130) extend perpendicularly from a container wall into the interior space (115), wherein the at least two compartments (130) extend further into the interior space (115) in the first axial section (111) than in the first axial section (111) second axial portion (112) to form a stirring portion (117) in the second axial portion (112) and to suppress rotational movement of the liquid medium in the first axial portion (111) due to rotation of the agitating tool (120).

Description

The present invention relates to an apparatus and a method for producing a fiber foam and in particular to the production of a fiber foam by means of a rapidly rotating stirring tool or a Flotationsinjektors, wherein the produced fiber foam can be used as a thermal insulation material.

background

Mineral wool, polystyrene foams or other mineral oil-based foams are common materials that are often used as thermal insulation materials. However, their production is very energy-intensive and disposal and recycling complicated - often only a thermal recovery is feasible.

It can also renewable resources such as wood wool, cork, or cellulose are used, which are available as thermal insulation materials mainly as plates, mats, felt or as beds. For example, to produce plates from these raw materials are pressed, for example, under a high pressure and high temperatures. Other insulating materials from renewable raw materials are felted into fleece-like mats such as flax, hemp, coconut fibers and cotton. It is also possible to produce flakes from waste paper by mechanical comminution and to introduce them as loose fill in the injection or spraying process. Known methods foam paper fibers to produce paper foam products by injection molding or extrusion, also known as flupis or paperfoam. Examples are in the EP 0 447 792 A1 and EP 2 556 953 A1 disclosed.

However, a solution of fiber foam comparable to mineral wool does not yet exist for renewable raw materials.

Therefore, there is a need for a replacement insulation for the conventional mineral wool and plastic foams, the replacement insulation having the same thermal and acoustic insulation values but being biodegradable. In particular, there is a need for thermal insulation materials from renewable resources.

Brief description of the invention

At least part of the above-mentioned problems are solved by a device according to claim 1 or 4 and a method for producing a fiber foam according to claim 7. The dependent claims define further advantageous embodiments of the subject-matter of the independent claims.

The present invention relates to an apparatus for producing a fiber foam. The device comprises a container, a rotatably mounted stirring tool and at least two compartments (e.g., fixed). The container defines an axially extending interior for receiving a liquid medium, the interior comprising a first axial portion and a second axial portion. The rotatably mounted stirring tool has an axis of rotation which runs parallel to the axial extent of the inner space. The at least two compartments extend vertically from a container wall into the interior, wherein the at least two compartments extend further into the interior space in the first axial section than in the second axial section to form a stirring zone in the second axial section in the first axial portion to suppress a rotational movement of the liquid medium as a result of rotation of the stirring tool.

Optionally, the container is cylindrically formed about the axis of rotation of the agitating tool and further includes a container inlet and a container outlet formed in the second axial portion. Optionally, the container further comprises at least one air passage in the first axial portion to allow pressure equalization to an environment.

Optionally, the stirring tool comprises a shank and a disc element. The shaft may extend through the first axial portion and define the axis of rotation, wherein the disc element is formed at one end of the shaft in the second axial portion perpendicular to the axis of rotation. Optionally, it is also possible that the shank does not extend through the first axial section but is inserted into the vessel from below (through the second axial section).

Optionally, the agitator provides a speed of at least 4,000 rpm or at least 5,000 rpm (e.g., about 7,000 rpm).

The present invention also relates to an apparatus for producing a fiber foam, comprising: a container defining an interior for receiving a suspension; a flotation injector for introducing air into the suspension; and a step diffuser at an exit of the flotation injector. The step diffuser has one or more step-shaped cross-sectional widenings to allow successive pressure drops along a flow direction of the To produce suspension and then spray the suspension into the container.

Optionally, the flotation injector operates on the jet pump principle and the step diffuser can cause sudden pressure drops along the flow direction of the suspension.

Optionally, the step diffuser comprises at least two step-shaped cross-sectional widenings which are spaced apart along the flow direction and which each form an abrupt increase in a flow diameter, wherein the cross-section can step-broaden, for example in a range between 1 mm and 20 mm.

Optionally, a funnel element is arranged at the outlet of the stage diffuser to provide a continuous cross-sectional enlargement along the flow direction of the suspension.

Embodiments thus solve at least part of the above-mentioned problems by an apparatus for producing bulky foams having a high porosity. In order to achieve this property, a self-priming flotation injector in combination with a stepped diffuser is used in particular. This works on the principle of a water jet pump and sucks air into the flowing suspension.

• - Bereitstellen einer Suspension in einem Behälter;
• - Erzeugen eines aufschwimmenden Schaumes durch:
  • ein Verrühren der Suspension mittels des Rührwerkzeugs bei einer Drehzahl von zumindest 2.000 U/min oder
  • ein Pumpen bzw. Einsprühen der Suspension in den Behälter; und
• - thermisches Trocknen des aufschwimmenden Schaumes.

The present invention also relates to a process for producing a fiber foam using one of the devices previously defined. The method comprises the steps:

• - Providing a suspension in a container;
• - generating a floating foam by:
  • stirring the suspension by means of the stirring tool at a speed of at least 2,000 rpm or
  • pumping or spraying the suspension into the container; and
• - thermal drying of the floating foam.

Optionally, the suspension of water, fibers and a surfactant (e.g., sodium lauryl sulfate, SDS) comprises at least one of the following: starch, whey protein, gelatin, lecithin, calcium carbonate, or other fillers. The surfactant is used to achieve foaming and the other additives improve product properties. The suspension can be formed with the following concentrations: pulp fibers with 0.98-1.9%, water with 94-99%, sodium lauryl sulfate with 0.01-0.9% and with the addition of starch with 0-1%, whey protein with 0-1%, gelatin with 0-1%, lecithin 0-1% and chalk 0-0.5% (concentrations may be% by mass). In addition, optionally, a flame retardant may be present, in which case in particular at least one of the following agents can be used: kaolin, soda, aluminum trihydroxide (ATH), aluminum phosphate (APP), melamine phosphate (MP), red phosphorus. In contrast to borax, these flame retardants, for example, have a low water hazard class and are readily biodegradable.

• - Einbringen des aufschwimmenden Schaumes in eine Form; und
• - Erhitzen der Form auf eine Mindesttemperatur, um den Schaum zu trocknen.

Optionally, the thermal drying is carried out pressure-free (eg without pressing) and comprises the following steps:

• - introducing the floating foam into a mold; and
• - Heating the mold to a minimum temperature to dry the foam.

Optionally, the thermal drying is performed at a minimum temperature for a predetermined period of time. The minimum temperature may be one of the following temperatures: 70 ° C, 80 ° C, 90 ° C or 100 ° C. The predetermined period of time should be until a desired degree of humidity is reached and may, for example, be between 12 and 24 hours.

Optionally, the speed of the stirring tool is at least 4,000 rpm, or at least 5,000 rpm, or between 4,000 and 7,000 rpm.

The present invention also relates to a use of a fiber foam produced by a previously defined method for at least one of the following applications: as a thermal insulation material, as an insulation material, as a sound insulation, as a filter, as a packaging material.

The desired properties are achieved in particular by the suspension flowing through having pulp and / or wood pulp fibers, water, sodium lauryl sulfate (SDS) and various additives, such as starch, whey protein, gelatin, lecithin and chalk, which are foamed in the described apparatus at high speeds become. The floating foam, for example, withdrawn after about 30 minutes and can be filled in molds. This is followed by a thermal drying, for example at 100 ° C. A pressing can be performed, but is not required according to embodiments.

In this way, embodiments offer compared to the prior art the The following advantages: Biodegradable foams can be produced with low material, cost and energy expenditure. Various known plastic foams can be removed in many applications such as insulation and insulation material, but also as packaging material by fibrous foam produced herewith. Embodiments also have the advantage that after a generation of the foam there is the possibility of dewatering or drying without the need for pressing.

list of figures

• 1 zeigt eine Querschnittsansicht einer Vorrichtung zur Herstellung des Faserschaums gemäß einem Ausführungsbeispiel der vorliegenden Erfindung.
• 2 zeigt eine weitere Querschnittsansicht der Vorrichtung aus der 1, wobei die beiden Fächer sich senkrecht zur Zeichenebene erstrecken.
• 3 zeigt eine Querschnittsansicht der Vorrichtung senkrecht zur Drehachse des Rührwerkzeugs.
• 4 zeigt einen Injektor mit einem Stufendiffusor.
• 5 zeigt ein Flussdiagramm für ein Verfahren zur Herstellung eines Faserschaums gemäß Ausführungsbeispielen der vorliegenden Erfindung.

The embodiments of the present invention will be better understood from the following detailed description and the accompanying drawings of the different embodiments, which should not, however, be construed as limiting the disclosure to the specific embodiments, but for explanation and understanding only.

• 1 shows a cross-sectional view of an apparatus for producing the fiber foam according to an embodiment of the present invention.
• 2 shows a further cross-sectional view of the device of the 1 , wherein the two compartments extend perpendicular to the plane of the drawing.
• 3 shows a cross-sectional view of the device perpendicular to the axis of rotation of the stirring tool.
• 4 shows an injector with a stage diffuser.
• 5 FIG. 10 shows a flow chart for a method of manufacturing a fiber foam according to embodiments of the present invention.

Detailed description

1 shows an embodiment of the apparatus for producing the fiber foam. The device comprises: a container 110 , a rotatably mounted stirring tool 120 and at least two subjects 130 , The container 110 defines an axially extending interior 115 for receiving a suspension (liquid medium), wherein the interior 115 a first axial section 111 and a second axial section 112 includes. The rotatably mounted stirring tool 120 has a rotation axis R parallel to the axial extent of the interior 115 , The at least two subjects 130 extend vertically from a container wall in the interior 115 into it, the at least two subjects 130 in the first axial section 111 further into the interior 115 extend than in the second axial section 112 to be in the second axial section 112 a stirring area 117 to form and in the first axial section 111 a rotational movement of the liquid medium as a result of rotation of the stirring tool 120 to suppress.

The container 110 is from the top through a cover 113 closed, for example, a passage for the stirring tool 120 having.

The container 110 may for example have a height of 10 ... 40 cm or about 20 cm. The stirring tool 120 may be different from the cover 113 extend so far that the disc element 125 has a distance to the ground of 5 ... 15 cm or about 10 cm. The disc element 125 may for example have a diameter of 2 ... 10 cm or about 6 cm. The container 110 may have a diameter of 8 ... 20 cm or about 12 cm. The subjects 130 can be in the first axial section 111 for example, up to the shaft 122 of the stirring tool 120 extend, leaving a gap of only a few millimeters or centimeters to allow sufficient space for possible vibrations of the stirring tool 120 to offer. The invention should not be limited to specific dimensions. The stated values can also be scaled up accordingly if, for example, relatively large amounts of foam are to be produced.

2 shows a cross-sectional view along the cross-sectional line AA from the 1 , The two subjects 130 now extend perpendicular to the drawing plane and the interior 115 extends in the container 110 from the floor to the top cover 113 , Optionally includes the top cover 113 a vent 119 , which serves to make a pressure equalization with an environment, so that in the container 110 the suspension can be filled or sprayed without a counter-pressure.

The stirring tool 120 comprises a disc element 125 at one end of a shaft 122 is mounted and driven by an external drive (not shown). In the embodiment shown, the drive takes place via an opening in the upper cover 113 so that the shaft 122 through the first axial section 111 extends through. In further embodiments, it is also possible that the stirring tool 120 from a bottom of the container 110 is driven. In this case, the shaft becomes 122 of the stirring tool 120 down through the container 110 led out and powered by a motor.

The container shown 110 Can be used to make from a colloidal suspension fiber foam with excellent insulation properties wherein the colloidal fiber foam is formed from two surfactant layers. To achieve this, the suspension is subjected to a rotation so that foam forms from the surfactant layers on a surface as a result of resulting trombus formation.

The stirring tool 120 is driven at a high speed to achieve the desired properties of the fiber foam. The speed of the stirring tool is, for example, greater than 3,000 rpm or at least 4,000 rpm or at least 5,000 rpm. The disc element 125 does not need to have any further structures. Due to the high rotation, a droplet-like shape forms in the container, as indicated by the dashed line 210 is shown. The shape of the subjects 130 (please refer 1 ) prevents rotation of the suspension at the edge of the container and in the first axial section 111 , Advantageously, the container 110 only so far filled with the suspension, so that in the resting state (without rotation), the surface of the suspension in the stirring 117 lies.

3 shows a cross-sectional view perpendicular to the axis of rotation R along the cross-sectional line BD from the 1 , with the line of sight on the right side of the cover 113 pointing vertically downwards (all underlying elements are dashed) and on the left side the cut along the cut line DC is shown. Accordingly, on the left side is the fan 130 shortened, while on the right side the dashed line shows the fan 130 represents how he almost reaches the shaft 122 enough.

4 shows an example of an injector, with the aid of which the suspension can be sprayed into a container. For spraying a different container can be used as in the 1 shown container 110 (because the stirring tool 120 and the subjects 130 for the production of the foam by spraying are not absolutely necessary). The injector includes a flotation injector 300 and a stage diffuser 400 downstream of the flotation injector 300 connects and both a river channel 340 provide for the suspension. The flotation injector 300 works on the principle of the jet pump and includes an inlet 310 for the suspension. The feed 310 narrows continuously along the flow direction F to an exit 312 , This increases the flow velocity. In the narrowing region, the inlet extends 310 through a chamber 320 that have an air intake 330 includes. The flow of the suspension through the inlet 310 to the exit 312 leads to a suction of air from the air inlet 330 That along with the suspension after the exit 312 is mixed.

The subsequent stage diffuser 400 exemplifies two step-shaped cross-sectional widenings 410 . 420 in which the cross-section spreads rapidly. First is the cross section of the river channel 340 in the stage diffuser 400 constant. At a first stage 410 the cross-section widens suddenly. Thereafter, the cross section again remains nearly constant until it reaches a second stage 420 again increased in leaps and bounds to stay constant again afterwards. The stage diffuser 400 may also have other stepped widenings. Subsequently, at the outlet of the stage diffuser 440 an optional funnel element 470 arranged, which has a continuously spreading cross-section along the flow direction F into the container.

In another embodiment, it is also possible that only one step is formed, which leads to a cross-sectional widening. The invention is not intended to be limited to a certain number of stages (step-shaped cross-sectional enlargements) 410 . 420 , ... be restricted. At the steps 410 . 420 .. The sudden cross-sectional enlargements lead to a sudden pressure drop, which produces the desired suspension mixture.

Although the invention is not intended to be limited to specific dimensions, it has proven advantageous if the container and / or the injector has certain dimensions.

For example, at the steps 410 . 420 , In each case a sudden increase in a flow diameter by a value in a range between 1 mm and 20 mm (or between 5 mm and 10 mm) take place. The flotation injector 300 may for example have a length of 10-20 cm and the flow channel 340 along the flow direction F may for example have an input diameter of 2 ... 5 cm or about 3 cm and an initial diameter of 0.5 ... 2 cm or about 1 cm. This leads to an increased flow velocity at the outlet, the air via the air opening 330 aspirated and mixed with the suspension. The container used for this purpose can be sufficiently large so that there is enough volume available for the sprayed suspension (eg more than 100 L or more than 1 m ³ or more than 10 m ³ ).

• - Bereitstellen S110 einer Suspension in einem Behälter;
• - Erzeugen S120 eines aufschwimmenden Schaumes durch:
  • ein Verrühren der Suspension mittels des Rührwerkzeug 120 bei einer Drehzahl von zumindest 2.000 U/min oder zumindest 4.000 U/min (oder zumindest 5.000 U/min), oder
  • ein Pumpen/Einsprühen/Injizieren durch den Flotationsinjektor; und
• - thermisches Trocknen S130 des aufschwimmenden Schaumes

5 shows a flow chart for a method for producing a fiber foam using a device described above. The method comprises the steps:

• - Provide S110 a suspension in a container;
• - Produce S120 a floating foam through:
  • stirring the suspension by means of the stirring tool 120 at a speed of at least 2,000 rpm or at least 4,000 rpm (or at least 5,000 rpm), or
  • a pumping / injecting / injecting by the flotation injector; and
• - thermal drying S130 of the floating foam

According to embodiments, sufficient foam is initially formed, which can then be skimmed off or drained by overflow. Thereafter, it can be filled or poured into molds, for example, and then dried. The drying can be done, for example, at the following temperatures: at about 70 ° C, about 80 ° C, about 90 ° C or about 100 ° C and for a predetermined period of time between 12 and 24 hours.

The suspension used may have the following composition: pulp fibers or wood pulp fibers at 0.98-1.9%, water at 94-99%, sodium lauryl sulfate at 0.01-0.9%; 0-1% starch, 0-1% whey protein, 0-1% gelatin, 0-1% lecithin and 0-0.5% chalk. Optionally, a flame retardant may be added (e.g., kaolin, soda, aluminum trihydroxide, aluminum phosphate, melamine phosphate, red phosphorus, or others).

• - mit geringem Material-, Kosten- und Energieaufwand herstellbar,
• - biologisch abbaubar und somit nachhaltig (nachwachsende Rohstoffe werden verwendet; als Zellstoff können beispielsweise Holzstofffasern oder NBSK-Zellstoff (Northern Bleached Softwood Kraft; eine Mischung aus Kiefer/Fichte) genutzt werden,
• - geeignet, um damit herkömmliche Kunststoffschäume abzulösen.

The resulting thermal insulation shows many advantages. In particular, the fiber foam is:

• - can be produced with low material, cost and energy expenditure,
• - biodegradable and therefore sustainable (renewable raw materials are used, for example wood pulp fibers or NBSK pulp (Northern Bleached Softwood Kraft, a mixture of pine / spruce) can be used as pulp,
• - suitable to replace conventional plastic foams.

The fiber foam produced in accordance with embodiments of the present invention may be used to advantage in the following applications: as an insulating material, as sound insulation, as a filter technique, or as a packaging material.

The features of the invention disclosed in the description, the claims and the figures may be essential for the realization of the invention either individually or in any combination.

LIST OF REFERENCE NUMBERS

110

container

111

first axial section

112

second axial section

113

cover

115

inner space

117

stirring region

119

vent

120

agitator

122

Shaft of the stirring tool

125

Disc element of the stirring tool

130

at least one fan

210

Trombenförmige surface curvature

300

Flotationsinjektor

310

funnel-shaped inlet

312

Outlet of the funnel-shaped inlet

320

air chamber

330

air supply

340

river channel

400

StepDiffusor

410, 420

Steps of the stage diffuser

440

Output of the stage diffuser

470

funnel member

R

axis of rotation

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0447792 A1 [0003]
• EP 2556953 A1 [0003]

Claims (14)

Device for producing a fiber foam, having the following features: a container (110) defining an axially extending interior (115) for receiving a liquid medium, the interior (115) including a first axial portion (111) and a second axial portion (112); a rotatably mounted stirring tool (120) whose axis of rotation (R) extends parallel to the axial extent of the inner space (115); and at least two compartments (130) extending perpendicularly from a container wall into the interior space (115), wherein the at least two compartments (130) extend further into the interior space (115) in the first axial section (111) than in the second axial portion (112) to form a stirring portion (117) in the second axial portion (112) and to suppress rotational movement of the liquid medium in the first axial portion (111) due to rotation of the agitating tool (120). Device after Claim 1 wherein the agitating tool (120) includes a shank (122) and a disc member (125), the shank (122) extending through the first axial portion (111) and defining the axis of rotation (R) and the disc member (125). is formed at one end of the shank (122) in the second axial gate (112) perpendicular to the axis of rotation (R). Device after Claim 1 or Claim 2 wherein the agitating tool (120) provides a speed of at least 4,000 rpm or at least 5,000 rpm. Device for producing a fiber foam, having the following features: a container defining an interior for receiving a suspension; a flotation injector (300) for introducing air into the suspension; and a staged diffuser (400) at an exit of the flotation injector (300), the staged diffuser (400) having one or more stepped cross-sectional spacers (410, 420, ...) to produce successive pressure drops along a flow direction (F) of the suspension, and is adapted to subsequently spray the suspension into the container. Device after Claim 4 wherein the step diffuser (400) has at least two step-shaped cross-sectional extensions (410, 420, ...) spaced apart along the flow direction (F) and each having a sudden increase in a flow diameter by a value in a range between 1 mm and 20 mm. Device after Claim 4 or Claim 5 in which a funnel element (470) is arranged at the outlet (440) of the step diffuser (400) in order to provide a continuous cross-sectional enlargement along the flow direction (F) of the suspension. Process for the production of a fiber foam using a device according to one of the Claims 1 to 6 method comprising the steps of: providing (S110) a suspension in the container (110); Generating (S120) a floating foam by: stirring the suspension by means of the agitating tool (120) at a speed of at least 2,000 rpm or pumping or spraying the suspension into the container; and thermal drying (S130) of the floating foam. Method according to Claim 7 wherein the suspension comprises water, fibers and a surfactant, the suspension in particular comprising one of the following substances: pulp fibers, wood pulp fibers, sodium lauryl sulfate, starch, protein, whey protein, gelatin, lecithin, filler such as calcium carbonate. Method according to Claim 8 wherein the providing of the suspension (S110) comprises the steps of: suspending: pulp fibers or wood pulp fibers at 0.98-1.9%, water at 94-99%, sodium lauryl sulfate at 0.01-0.9%; Adding 0-1% starch, 0-1% whey protein, 0-1% gelatin, 0-1% lecithin and 0-0.5% chalk, optionally adding a flame retardant, more particularly at least one of the following Substances includes: kaolin, soda, aluminum trihydroxide, aluminum phosphate, melamine phosphate, red phosphorus. Method according to one Claims 8 to 10 wherein the thermal drying (S130) is pressure-free and comprises: introducing the floating foam into a mold; and heating the mold to a minimum temperature to dry the foam. Method one of Claims 7 to 10 wherein the thermal drying (S130) is performed at a minimum temperature for a predetermined period of time and the minimum temperature is one of The following temperatures are: 70 ° C, 80 ° C, 90 ° C or 100 ° C. Method one of Claims 7 to 11 , wherein the predetermined period of time is between 12 to 24 hours. Method according to one of Claims 7 to 12 wherein the speed of the stirring tool (120) is at least 4,000 rpm or at least 5,000 rpm, in particular at 7,000 rpm. Using a fiber foam, with a method according to one of Claims 7 to 13 for at least one of the following uses: as thermal insulation material, as insulating material, as sound insulation, as filter, as packaging material.

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