Spouted bed wood chip debarker/cleaner

This invention relates to a spouted bed wood chip debarker/cleaner. Such structures of this type, generally, cause wood chips and bark to undergo attrition by accelerating the wood chips and bark with a jet of air. In particular, the accelerated wood chips and bark are impinged on a screen. When the wood chips hit the screen, bark and wood chips experience attrition. Small pieces of bark and other debris (sand, for example) will be exhausted through the screen which is too fine of a mesh to let desirable size wood chips be exhausted.

BACKGROUND OF THE INVENTION 
1. Field of the Invention: 
This invention relates to a spouted bed wood chip debarker/ cleaner. Such 
structures of this type, generally, cause wood chips and bark to undergo 
attrition by accelerating the wood chips and bark with a jet of air. In 
particular, the accelerated wood chips and bark are impinged on a screen. 
When the wood chips hit the screen, bark and wood chips experience 
attrition. Small pieces of bark and other debris (sand, for example) will 
be exhausted through the screen which is too fine of a mesh to let 
desirable size wood chips be exhausted. 
2. Description of the Related Art: 
It is known, in prior debarking systems, to remove bark from wood chips by 
mechanically agitating the wood chips in a drum. This agitation has been 
done with and without items other than wood chips, i.e., metal balls, 
metal blocks, logs, etc. These approaches have generally removed attached 
bark from the wood chips, but the loosened bark was then ground back into 
the wood chips, which is undesirable. 
It is also known, in debarking systems, to employ the use of a stream of 
gas. Exemplary of such prior art is U.S. Pat. No. 4,140,281('281) to O. T. 
Fulghum et al., entitled "Separation of Dirt and Bark from Wood Chips". 
The '281 reference entails the mixing of wood chips in a stream of gas, 
impinging the resulting stream of dispersed solids onto an impact surface 
to dislodge particles of dirt and bark from the wood chips, and 
thereafter, subjecting the solids to a classifying operation which 
separates the finer particles of dirt and bark from the coarser wood 
chips. However, a more advantageous debarker/cleaner would be presented if 
such amounts of dirt and bark could be more easily removed. 
It is apparent from the above that there exists a need in the art for a 
system which is capable of debarking/cleaning wood chips, and which at 
least equals the debarking/cleaning characteristics of the known 
debarkers/cleaners, but which at the same time is able to more easily 
debark/clean the wood chips. It is the purpose of this invention to 
fulfill this and other needs in the art in a manner more apparent to the 
skilled artisan once given the following disclosure. 
SUMMARY OF THE INVENTION 
Generally speaking, this invention fulfills these needs by providing a 
spouted bed wood chip debarker/cleaner, comprising a spouted bed means 
having a first and second end, an air inlet means operatively connected to 
the first end of the bed means, a wood chip inlet means operatively 
connected to the bed means, a wood chip outlet means operatively connected 
to the bed means and located a predetermined distance away from the wood 
chip inlet means, a tube means having a first and second end located 
substantially within the bed means such that the first end of the tube is 
located substantially adjacent to the first end of the bed means and the 
second end of the tube means is located substantially adjacent to the 
second end of the bed means, and a screen means operatively connected to 
the second end of the bed means. 
In certain preferred embodiments, the wood chip inlet and outlet means are 
located substantially above the air inlet means. Also, the tube means is a 
draft tube. 
In another further preferred embodiment, the wood chips are more easily 
debarked/cleaned due to the acceleration of the wood chips with the jet of 
air. As the accelerated wood chips are impinged on the screen, wood chips 
and bark undergo attrition and debris is removed from the wood chips. The 
debris is exhausted through the screen while the desirable wood chips are 
retained and transported back into the debarker/cleaner. Some of the 
desirable wood chips are transported out of the debarker/cleaner. 
The preferred wood chip debarker/cleaner, according to this invention, 
offers the following advantages: ease of assembly and repair; good 
stability; good durability; excellent economy; and excellent 
cleaning/debarking characteristics. In fact, in many of the preferred 
embodiments, these factors of economy and cleaning/debarking are optimized 
to an extent that is considerably higher than heretofore achieved in 
prior, known wood chip cleaners/debarkers.

DETAILED DESCRIPTION OF THE INVENTION 
With reference to the FIGURE, there is illustrated an advantageous 
environment for the use of the concepts of this invention. As shown in the 
FIGURE, wood chip debarker/cleaner 2 includes, in part, bed 4, air inlet 
6, air stream 8, wood chip inlet 10, uncleaned wood chip stream 12, draft 
tube 14, screen 16, bark and other debris 18, wood chip outlet 20, and 
debarked/cleaned wood chip stream 22. 
With respect to bed 4, air inlet 6, wood chip inlet 10, draft tube 14, and 
wood chip outlet 20, these, preferably, are constructed of any suitable 
high strength material, such as metal. The mesh size of screen 16, 
preferably, is such that desirable size wood chips will not be exhausted 
through screen 16. A screen size hole of approximately three-sixteenths of 
an inch or less would be sufficient to accomplish the task. 
During the operation of wood chip debarker/cleaner 2, whole tree wood chips 
12 are fed into bed 4 through wood chip inlet 10. Wood chips 12 may also 
be introduced into bed 4 with jet of air through air inlet 6. Wood chips 
12 drop down to the bottom of bed 4 in the annular ring outside of draft 
tube 14. Steep angled sides at the bottom of bed 4 form a funnel which 
feeds wood chips 12 to the center of bed 4. At the center and bottom of 
bed 4 is a jet of air 8 with sufficient velocity, volume and an 
appropriate diameter to entrain the wood chips 12 in the air flow. 
Preferably, the air velocity is such that the wood chips and bark 
experience attrition when they impact screen 16. Typical air velocities 
are approximately 500 to 3,000 feet/minute. The entrained wood chips 12 
are carried up inside of a draft tube 14 and are accelerated. Wood chips 
12 and air 8 exit the top of draft tube 14 and impinge on screen 16 at the 
top of the debarker/cleaner 2. When the wood chips 12 impinge upon screen 
16, on wood chips 12 experience attrition. Air 8 exits bed 4 through 
screen 16 along with debris 18 sufficient to fit through the screen 16, 
i.e., bark, dirt, sand, pins, fines, and leaf matter. Wood chips 12 
impinging on screen 16 either bounce off of screen 16 or are pushed off of 
screen 16 by other wood chips 12 or the air flow. Wood chips 12 then move 
back to the bottom of bed 4 to repeat the process. Bark and/or debris may 
also be removed from wood chips 12 as wood chips 12 move to the bottom of 
bed 4. Debarked/cleaned wood chips 22 leave the debarker/cleaner 2 through 
outlet 20. 
It is to be understood that the present invention can be used in either a 
batch mode or a continuous mode. The spouted bed wood chip 
debarker/cleaner 2 can be used in either a parallel arrangement or a 
series arrangement of debarkers/cleaners or both. There are a number of 
variables that can control wood chip attrition/chip cleaning. For example, 
the impingement velocity of the wood chips on the screen will influence 
debarking/cleaning. Also, the residence time of wood chips 12 in the 
debarker/cleaner 2 affect attrition cleaning. Finally, screen 16 mesh size 
will impact attrition/cleaning. 
Once given the above disclosure, many other features, modifications or 
improvements will become apparent to the skilled artisan. Such features, 
modifications or improvements are, therefore, considered to be a part of 
this invention, the scope of which is to be determined by the following 
claims.