Plastic and nonmetallic article shaping or treating: processes – Recycling of reclaimed or purified process material – Of gaseous process material
Patent
1987-07-16
1990-05-01
Lorin, Hubert C.
Plastic and nonmetallic article shaping or treating: processes
Recycling of reclaimed or purified process material
Of gaseous process material
241 18, 241 19, 241 28, 264115, 264116, 264121, 264518, 425 831, 425197, 425217, D01G 700, D01G 2100, D04H 100
Patent
active
049216503
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to the dry forming of webs.
Dry forming implies that the fibre material dispersed in air is caused to flow against a running forming wire. The fibres precipitate on the wire while the air passes therethrough. In commercially available plants for dry forming, the web is formed by using nets or screen plates, through which the fibres are to pass prior to their precipitation on the wire. The finer the net, the cleaner the web, but at the same time the fibre flow is reduced and an ever increasing amount of fibres are separated as reject and recycled for repeated defibration. The result is low capacity and degradation of the fibres. A further disadvantage is that the fibres easily can clog the holes in the net or screen and thereby cause non-uniform fibre distribution.
SUMMARY OF THE INVENTION
The present invention relates to a method and device for forming a web where the aforesaid disadvantages are eliminated. According to the invention, no nets or screen plates are used in connection with the forming, but undefibrated fibres are separated at a previous stage, and the distribution of the fibre material on the forming wire is brought about in that the fibre dispersion on its path to the forming wire is caused to flow along a curved surface. The characterizing features of the invention become apparent in greater detail in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described in greater detail in the following by way of an embodiment thereof and with reference to the accompanying drawings.
FIG. 1 shows a forming head according to the invention.
FIG. 2 is a basic flow diagram for a plant according to the invention.
FIG. 3 is a flow diagram for a preferred embodiment.
DESCRIPTION OF THE INVENTION
The forming head 1 is provided with an inlet 2, which is designed so as to have successively decreasing height and increasing width, The cross-section of the inlet 2, thus, can transform from circular to rectangular. The final height of the inlet 2 is adjustable by means of a swing lip 3, which co-operates with the stationary lower wall 4 of the inlet. The lip 3 can be divided into individually adjustable sections for controlling the final height of the inlet 2 in the transverse direction and thereby controlling the transverse profile of the web. After the lip 3, the wall 4 transforms to a continuous single-curved convex surface 5. the radius of which must exceed 100 mm. This curved surface 5 leads to an accept outlet 6, which is so directed downwards that it forms an angle of about 90.degree. inlet 2. Other angles between 45.degree. and 180.degree., however, can also be used.
A screen 7 is located spaced from the curved surface 5 and extends along the entire width of the inlet, thereby forming a passage 8 between the screen 7 and curved surface 5. The narrowest section of the passage is defined by the leading edge 9 of the screen which is located after about half of the curved surface 5. The screen 7 being movable, the distance between the leading edge of the screen and the curved surface 5 can be varied. The screen 7 is substantially in parallel with a tangent to the curved surface 5 in a point directly in front of the edge 9. The screen 7 delimits the accept outlet 6 from a reject outlet 10.
Above the screen 7 an adjustable wall 11 is located, which together with the edge 9 of the screen defines a passage 12 above the screen 7. This passage 12 communicates with the reject outlet 10. The wall 11 is pivotal about a hinge 15 by means of an adjustable stay member 4. The wall 11 further is sealed against the upper portion of the forming head 1 by a sealing 15, thereby preventing return flow of the reject in the forming head.
The fibre material is supplied to the forming head in the form of fibres dispersed in air. The flow rate in the narrowest section of the inlet must exceed 100 m/sec. Hereby the fibres are dispersed which may have entangled (fibre fluff pieces). The incoming fibre/air flow deflects along the curved surface 5, which should be
REFERENCES:
patent: 2845661 (1958-08-01), Sverde et al.
patent: 3482287 (1969-12-01), Flewwelling
Ek Bo R.
Eriksson Kjell G.
Eriksson Nils L.
Wallin Stig G.
Lorin Hubert C.
Sunds Defibrator Aktiebolag
LandOfFree
Method and apparatus for liquid treatment of pulp does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for liquid treatment of pulp, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for liquid treatment of pulp will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-828281