# US 8,783,591 B2 · Method of preparing wood fibers for a cultivation substrate

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- Number: US 8,783,591 B2
- Document ID: US8783591B2
- Status: Granted
- Kind: B2
- Application number: 13/330,121
- Filed: 2011-12-19
- Published: 2013-03-28
- Granted: 2014-07-22
- Earliest claimed: 2011-09-26
- Assignees: Florentaise
- Applicants: Eric Beaudet; Jerome Cowper
- Inventors: Eric Beaudet; Jerome Cowper
- Web page: https://patentgrep.com/patent/US8783591B2

## CPC

- D21B 1/30: Defibrating by other means
- A01G 24/23: Wood, e.g. wood chips or sawdust
- D21B: FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
- A01G: HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING (picking of fruits, vegetables, hops or the like A01D46/00; propagating unicellular algae C12N1/12)

## Abstract

Wood chips are fed into a sheath containing two parallel screws that mesh with each other, their respective threads having, at least an upstream series of segments and a downstream series of segments, each of which comprises a drive upstream zone in which the chips are driven downstream and a braking downstream zone through which the chips are forced, the chips thus being driven through the sheath while being braked in the braking zones and while being transformed into fibers. The transit time for which the chips remain in the sheath lies in the range 1.5 s to 80 s, and provision is made for the pressure to be at least substantially equal to 90 bars upstream from the braking zone of the upstream series, so that a temperature lying in the range 120° to 150° C. is reached inside the sheath (10) without supplying external heat.

## Claims

### Claim 1

A method of preparing wood fibers for use in the composition of a cultivation substrate, wherein wood chips are fed into a defibration sheath containing two parallel screws driven in rotation in such a manner as to mesh with each other via their respective threads, said threads having, in succession, in the direction going from upstream to downstream, at least an upstream series of segments and a downstream series of segments, each of which comprises a drive upstream zone in which the chips are driven downstream and a braking downstream zone through which the chips are forced under the drive effect procured by the upstream zone, the chips thus being driven through the sheath while being braked in the braking zones and while being transformed into fibers that are recovered at the outlet of the defibration sheath, the transit time for which the chips remain in the sheath lying in the range 15 s to 80 s, and provision is made for the pressure to be at least substantially equal to 90 bars upstream from the braking downstream zone of the upstream series, so that a temperature lying in the range 120° to 150° C. is reached inside the sheath without supplying external heat.

### Claim 2 (depends on 1)

A method according to claim 1, wherein the transit time for which the chips remain in the sheath lies in the range 25 s to 60 s.

### Claim 3 (depends on 1)

A method according to claim 1, wherein the screws are caused to turn at a speed lying in the range 250 rpm to 400 rpm.

### Claim 4 (depends on 1)

A method according to claim 1, wherein the screws are caused to turn at a speed lying in the range 300 rpm to 380 rpm.

### Claim 5 (depends on 4)

A method according to claim 4, wherein, in the braking downstream zones, each reverse thread of the braking downstream zone of the downstream series has in the range 2 notches to 6 notches, the ratio of the sum of the sections of the notches of such a thread to the fiber output rate lying in the range 60 mm2/m3h−1 to 80 mm2/m3h−1.

### Claim 6 (depends on 4)

A method according to claim 4, wherein, in the braking downstream zones, each reverse thread of the braking downstream zone of the downstream series has in the range 2 notches to 6 notches, the ratio of the sum of the sections of the notches of such a thread to the fiber output rate lying in the range 70 mm2/m3h−1 to 75 mm2/m3h−1.

### Claim 7 (depends on 1)

A method according to claim 1, wherein, in the drive upstream zones, the chips are put into contact with forward threads, whereas, in the braking downstream zones, the chips are put into contact with reverse threads.

### Claim 8 (depends on 1)

A method according to claim 1, wherein, in the braking downstream zones, the chips are caused to pass through notches provided in the threads.