Method and apparatus for extraction of aloe vera gel

An apparatus for extraction of uncontaminated aloe vera gel from the leaves of aloe vera plants. The harvested leaves of the aloe vera plants are positioned between a pair of endless moving belts for passing by a plurality of crushing rollers arranged in a desired pattern. The rollers first crush the core of the leaf to enable the gel to flow internally while a second set of rollers extrudes the gel from the leaf. The crushed leaf and extruded gel is then deposited on a drain grate to enable gravity flow separation of the gel from the crushed leaves. The drainage grate is sloped in order that the leaves will slowly move across the drain grate to enable separation of the gel while removing the leaf from the gel collection area prior to the flowing of the contaminate aloin from the leaf.

BRIEF SUMMARY OF THE INVENTION 
1. Technical Field 
This invention relates broadly to the extraction of aloe vera gel from 
agricultural plant leaves and in particular to an apparatus for extracting 
high purity aloe vera gel in a commercial quantity. 
2. Background Art 
While the present invention relates broadly to the field of a method and 
apparatus for extracting a liquid component from agricultural products, 
the present invention is disclosed in the setting of an embodiment of a 
method and apparatus for obtaining a desired gel extract from the leaves 
of aloe vera plants. 
Most agricultural products contain a single desirable juice or liquid to be 
extracted by extruding the ripened product. For example, citrus fruits 
such as oranges or grapefruit or other fruits, such as apples, are 
frequently processed by crushers that force or extrude the juice from the 
fruit for enabling subsequent separation of the solid or pulp material 
from the juices. 
The following patents of which Applicant is presently aware relate to 
various methods and apparatus for extracting a desired liquid from 
agricultural products or for separating a liquid from a slurry: 
______________________________________ 
U.S. PAT. NO. PATENTEE 
______________________________________ 
91,210 C. L. Carter 
198,226 Zacharias Thoman 
248,083 O. F. Boomer 
348,019 J. E. Jones 
1,659,733 F. M. Barbeck 
3,126,819 A. Wehner 
3,601,039 Donald S. Schover 
3,613,564 M. A. Wheeling, et al 
3,720,159 Otto Gunkel 
3,851,685 Ahrweiler, et al 
______________________________________ 
The Boomer U.S. Pat. No. 248,083 discloses a roller press having a 
plurality of gear driven rollers pressing on a pair of movable endless 
belts to continuously squeeze liquid from the material placed between the 
moving belts. Cider is one of a number of liquids listed as suitable for 
extraction from apples by this machine. The Carter U.S. Pat. No. 91,210 is 
entitled "Cider Mill" and discloses a pair of slatted endless moving belts 
that provide a converging pressing channel therebetween for crushing 
apples to extract and separate the juice. 
Another embodiment "Cider Mill" is disclosed in Thoman U.S. Pat. No. 
198,226. The apples are ground before an endless belt passes or carries 
them between a series of pairs of pressing rollers to extrude the juice. 
The "Cider Press" disclosed in Jones U.S. Pat. No. 348,019 also uses an 
endless carrying belt passing between pairs of pressing rollers. 
U.S. Pat. No. 1,659,733 to Harbeck also discloses an endless apron 
operating "Cider Press" but is of much later vintage. To increase the 
capacity of the press spring created urging or pressing forces are used to 
produce the constant crushing of the fruit to extract the liquid. 
The more recent patents noted above disclose rather sophisticated presses 
for various liquid extraction purposes. For example, press platens having 
an arrangement for reducing contact friction between the moving belt and 
the crushing force of the platens are disclosed in Ahrweiler et al. U.S. 
Pat. No. 3,851,685. A sequential operated juice press having a controlled 
arrangement for maintaining the crushing force on the fruit for a 
predetermined time to assure maximum juice extraction and unique 
separation or flow path through the endless filter cloth for the extracted 
liquid is disclosed in Gunkel U.S. Pat. No. 3,720,159. U.S. Pat. No. 
3,613,564 to Adamski et al discloses a dewatering press for solid sludge 
formation as does Schover U.S. Pat. No. 3,601,039. A sludge dewatering 
press is also disclosed in Wehner U.S. Pat. No. 3,126,819. 
U.S. Pat. No. 3,878,197 to Maret is entitled "Process For Preparing 
Extracts Of Aloe Vera" and sets forth many of the problems encountered in 
extracting the desired gel from the center of the leaves of the aloe vera 
plants. The aloe vera plant is more formally known as aloe barbadensis 
Miller and provides a large triangular shaped leaf having a thickness that 
may approach one inch (2.54 cm). The leaves of the aloe vera plant have a 
relatively dense outer layer, rind, or peel surrounding the relatively 
soft leaf core that is filled with aloe vera gel. Disposed between the gel 
containing core and the outer peel is a thin liquid layer of aloin which 
is released when the peel is cut or broken, such as during harvesting. The 
aloin is a highly undesirble yellowish colored liquid extract which is 
considered a contaminate for the aloe vera gel extract. Among the 
undesirable characteristics of aloin are a bitter taste and a cathartic 
action which render the aloe vera completely unacceptable for human 
consumption. The bright yellowish color of the aloin also colors any aloe 
vera containing product intended for external use that substantially 
reduces consumer acceptance. As noted in the Maret patent, crushing the 
entire aloe vera leaves, such as with the equipment or apparatus disclosed 
in the previously mentioned patents, results in a contamination of the gel 
with the yellowish aloin which produces a low grade extract of limited 
commercial use. At the present time, there is no available commercial 
process for separating the aloin from the gel to upgrade the contaminated 
gel. As a result, the contamination of the aloe vera gel renders the gel 
valueless. 
Because of the contamination of the gel by the aloin, most gel extraction 
has been done by hand trimming or filleting each leaf to remove all traces 
of the layer of aloin. This has entailed cutting the peel away from the 
core of gel material and thereafter squeezing the fillet or core of the 
leaf in a conventional manner to extract the gel, as is disclosed in the 
Maret Patent. While this method produced the desirable uncontaminated gel, 
it was an extremely wasteful operation as a substantial portion of the gel 
containing core portion of each leaf was severed and discarded. In 
addition, the process of filleting each leaf was time consuming, expensive 
and somewhat hazardous due to the sharp cutting knives employed. 
BRIEF SUMMARY OF THE INVENTION 
The present invention relates to a method and apparatus for extracting high 
purity aloe vera gel from the leaves of the aloe vera plants. 
The harvested leaves are cleansed or washed to remove any trace of the 
undesired aloin remaining on the outer rind from the severing of the 
leaves during the harvesting operation. The washed leaves are then passed 
through an extraction press having a pair of continuously moving belts 
positioned between crushing rollers arranged to selectively force the aloe 
vera gel from the core of the leaf and enable gravity flow separation of 
the gel from the leaf before the aloin in the leaf rind begins to extrude 
or flow. The crushed leaves are removed from the aloe vera gel recovery 
zone before the aloin can contaminate the extracted aloe vera gel. The 
resulting uncontaminated aloe vera gel is then collected and processed 
further as desired. 
The continuously moving endless belts enable a high rate of operation as 
they greatly speed movement of each leaf between the crushing rollers as 
well as increasing gel recovery by assuring complete crushing of each 
leaf. The apparatus and method of use of the present invention provide a 
commercial operation for extracting the aloe vera gel without having to 
first remove the layer of aloin.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The apparatus, generally designated A, of the present invention is best 
illustrated in the perspective view of FIG. 1. The apparatus provides a 
commercial method for the extraction of aloe vera gel from harvested 
leaves of the aloe vera plant with a minimum of prior treatment. The 
triangular shaped aloe vera leaves are normally in the range of 7.0 to 
10.0 centimeters wide at the base and usually have a length of 
longitudinal axis exceeding 50.0 centimeters. The leaves are shaped 
substantially in the form of equilateral triangles when harvested with the 
base of the triangle formed by the severed or cut end portion of the leaf 
to separate it from the trunk of the aloe vera plant. 
The aloe vera leaves are formed of a relatively soft core filled with the 
desired aloe vera gel. The core is surrounded by a protective dense outer 
peel or rind. Disposed between the outer peel and the core is a layer of 
aloin, a yellowish contaminant of the aloe vera gel. The presence of the 
layer of aloin has in the past required that it be separated from the core 
prior to crushing the core to extrude the aloe vera gel. The apparatus A 
of the present invention provides a method for recovering the aloe vera 
gel without the need to remove the layer of aloin prior to crushing the 
aloe vera leaf for extracting the gel. 
The apparatus A of the present invention includes a structural support 
frame, generally designated 10 formed with support members of sufficient 
strength and rigidity to maintain the apparatus A in operating condition 
or relationship. The particular arrangement of the members of the support 
frame is not critical to the present invention and are described for 
illustrative purposes only, since those skilled in the art may desire to 
modify the support frame for other purposes 
In the illustrated embodiment (FIG. 1), a rectangular base is formed by 
horizontally disposed members 12 and 14 having corresponding members (not 
illustrated) disposed in parallel relationship to form the rectangular 
base. The horizontal members 12 and 14 are supported by a suitable 
plurality of support legs 16 in the conventional manner. 
A plurality of parallel upwardly extending or vertical support members 20, 
22 and 23 extend upwardly from the side horizontal member 12. The vertical 
members 20 and 22 are connected at spaced intermediate locations by 
horizontal side structural support members 24, 26 and 28 as desired. 
Suitable horizontal cross members 30 and 32 may be employed to connect 
with vertical members 22a and 20a with sufficient rigidity and strength. 
The back side of the apparatus A is arranged in a similar manner. 
As noted hereinabove, the precise arrangement or location of the various 
members of the support frame 10 may be arranged in a different manner as 
desired as long as the resulting frame is of sufficient strength and 
rigidity to maintain the components of the apparatus A in operating 
relationship when processing the aloe vera leaves. 
The apparatus A further includes a first or lower pair of belt drums 40 and 
42 that are rotatably mounted with the support frame 10 in any desired 
conventional manner at spaced apart locations with the drums 40 and 42 
extending substantially the width of the cross members 14. Disposed about 
the first pair of belt drums 40 and 42 is a first endless belt 44 formed 
of suitable impervious flexible material. Disposed above the first pair of 
belt drums 40 and 42 is a second or upper pair of belt drums 46 and 48 
that are also rotatably mounted with the support frame 10 at spaced apart 
locations. (In the illustrated embodiment, the pairs of belt drums are 
spaced apart different distances, but it is understood that the pairs of 
belt drums may be spaced apart the same distances without departing from 
the present invention). A second endless belt 50 similar to the belt 44 is 
disposed about the second pair of belt drums 46 and 48 and in contact with 
the belt 44 to form a zone therebetween. 
Mounted with the support frame 10 is a suitable power or drive means such 
as electric motor 52 having rotatable pulley 54 operably connected thereto 
such as by a suitable intermediate gear box 56. The gear box 56 may also 
be used as the mounting base for the electric motor 52 to the support 
frame 10. 
While the illustrated manner of driving or rotating the belt drums 48 and 
42 in opposite directions will be described, it will be understood that 
other arrangements for driving either one or both of each pair of belt 
drums are well known to those skilled in the art. In the illustrated 
embodiment, belt 57 mounted with pulley 54 rotates pulley 58 mounted with 
the belt drum 48 for effecting its rotation. Spur gear 60 mounted with the 
belt drum 48 engages spur gear 62 for rotating the belt drum 42 in the 
opposite direction in order that the belts 44 and 50 move in the same 
direction between the pairs of belt drums. A pulley 64 also mounted on 
belt drum 48 drives the belt 66 for turning the pulley 68 on roller wiper 
70 for a purpose to be described in greater detail hereinafter. While the 
use of the spur gears 60 and 62 would indicate that there would be 
synchronized movement of the belt drums 42 and 48 and thereby no relative 
movement between the contacting portions of the first belt 44 and the 
second belt 50, it would also be understood that a slight variation or 
slippage in movement between the belts may be desired or may result from 
slippage. The desired rotation of the belt drums 48 and 42 is arranged 
that when the leaf L is positioned at the inlet end on the endless belt 44 
the leaf will be fed between the endless belts 44 and 50 for movement 
through the apparatus A from adjacent the rollers 40 and 46 towards the 
driven rollers 42 and 48 where the leaf L will be discharged from the zone 
between the belts 44 and 50. 
Angularly disposed adjacent the lower discharge belt drum 42 is a drainage 
platform or grate 72 which is pivotly mounted with the support frame 10 to 
ride only endless belt 44 to enable the leaves L to slide or transfer from 
the lower belt 44 onto the drainage grate 72. The drainage grate 72 
enables the gravity flow of the extruded gel or liquid from the aloe vera 
leaf into a receiver or collecting vat 74 disposed below the collection 
grid. The rotating wiper 70 serves to prevent flow of the desired gel from 
the grate 72 and directs such flow back into the receiver 74, and is wiped 
clean by rubber wiper attached to receiver 74. Suitable piping, not 
illustrated, is provided to the receiver 74 for collecting the aloe vera 
gel for further processing as desired. 
As will be explained in greater detail hereinafter, the grate 72 is 
tapered, angled or slanted to enable the crushed aloe vera leaves to slide 
across the grate 72 at a rate or speed which will enable the desired aloe 
vera gel to separate from the leaf and flow into the receiver 74. The 
crushed leaf will slide off of the grate to a collection bin (not 
illustrated) for discarding before the undesired aloin begins to flow from 
the leaf. 
To crush the aloe vera leaves, a plurality of rollers is disposed between 
the first pair of belt drums 40 and 42 for supporting a crushing portion 
of the first or lower endless belt 44. The plurality of rollers is mounted 
by a plurality of air cylinders 82 having a first end 82a operably 
connected with the horizontal support member 24. By mounting the plurality 
of rollers 80 with the air cylinders 82 arranged to maintain the plurality 
of rollers urged upwardly towards the belt 44 a controlled crushing force 
is provided to the zone between the belts 44 and 50 while enabling 
sufficient limited movement of the plurality of rollers 80 and lower belt 
44 to enable passage of thickened portions of the leaves L. 
For coacting with the lower plurality of rollers 80 for crushing the aloe 
vera leaves L, a plurality of rollers are arranged on the horizontal 
member 26 of the support frame 10 in the same predetermined crushing 
pattern. The plurality of rollers, generally designated R, are arranged in 
a two part pattern, best illustrated in FIG. 2 for crushing the aloe vera 
leaves positioned between the first and second endless belts in the zone 
between the plurality of rollers R and the plurality of rollers 80. The 
plurality of rollers R are journaled between horizontal support member 26 
and companion side horizontal support member 26a of the support frame 10. 
As each of the plurality of rollers R is mounted with the support frame in 
a similar manner only one of the plurality of conventional roller 
mountings will be described in any detail. In particular, each of the 
plurality of rollers R has a mounting shaft 100 extending between the 
horizontal members 26 and 26a and which are mounted therewith by securing 
pins (not illustrated). The support shafts 100 are of sufficient rigidity 
to maintain the rollers R in position as the aloe vera leaves L move past 
the rollers 
Each of the shafts 100 has one or more plastic bushing or belt contacting 
rollers R rotatably mounted thereon for rolling contact with the upper 
belt 50 and urging the endless belts 44 and 50 into contact with the lower 
plurality of rollers 80. The rollers R are arranged in a predetermined 
pattern of two sets or steps for initially crushing the leaf to provide an 
internal rupturing of the core to enable the gel to flow from the leaf and 
a second set of rollers to extrude the gel from the leaf. The first set of 
rollers are essentially v-shaped (FIG. 2) so the initially engaged base of 
the leaf L (shown in phantom) is contacted adjacent the outer peel with 
the rollers 102 located on the initial shaft 100. The rollers 102a and 
102b are spaced apart a sufficient distance for engaging the largest width 
leaf L and beginning the crushing of the core at the intersection of the 
rind and the outer portion of the harvesting cut or base of the triangle. 
The roller 104a and 104b mounted on the next shaft 100b are spaced closer 
together with a near or slightly overlapping relationship with the rollers 
102a and 102b to continue to force the gel outwardly into the space 
vacated by rollers 102a and 102b. The next set of rollers 106a and 106b 
are positioned in a similar manner but slightly closer together. Likewise, 
108a and 108b are positioned even closer together. The roller 109 is the 
sole roller located on that particular shaft and is centered in the 
machine. The resulting pattern formed by the first set of rollers provides 
a crushing action across the width of the leaf L for rupturing the core to 
form an outwardly flow passage to allow the escape of the gel from the 
core. Thereafter, the increasing width of rollers 110, 112, 114 and 116 
are used to extrude or force the aloe vera gel from the core of the leaf. 
For some reason, either viscosity of the aloin fluid or the softness of 
the core of the plant relative to the rind, the gel commences to flow 
after crushing the leaf before the aloin. 
Because of this feature when the leaf and extruded gel are then discharged 
between the belts 44 and 50 onto the grate 72 the gel is extruded, but not 
the aloin. The crushed leaves L slide across the grate 72 slowly in order 
that the aloe vera gel will separate from the leaf and flow by gravity 
into the receiver 74. Blade wipers (not illustrated) are used to scrape 
the gel from the lower belt 44 and upper belt 50 in a conventional manner. 
Likewise, the rotating scraper or roller 70 is used to catch the aloe vera 
gel flowing downwardly on the grate 72 for directing it into the receiver 
74 to enhance or increase the recovery of the desired gel. The leaves L 
slide from the grate 72 into a discard container before the aloin 
commences to flow from the leaf in order that an uncontaminated gel, is 
collected within the receiver 74. 
USE AND OPERATION OF THE PRESENT INVENTION 
In the use and operation of the present invention, the apparatus A is 
assembled and operated in the manner previously described. 
The aloe vera leaves L which have been harvested in the field by severing 
the base of the leaf from the plant are then washed or otherwise cleaned 
to remove any trace of aloin from the leaf resulting from the severing of 
the leaf during the harvesting operation. The cleansed leaf is then placed 
upon the endless belt 44 with the severed end toward Apparatus A and urged 
between the moving endless belts 44 and 50. The moving belts 44 and 50 
grasp the leaf L in the condition illustrated. The endless belts 44 and 50 
then move the leaf L between the plurality of rollers R and 80 which first 
crush the leaf L to enable the flow of the gel in the core of the leaf and 
then extrude the gel from the leaf with the second set of rollers. The 
leaves are then discharged from the belts 44 and 50 onto the discharge 
grid 72 where the gel is enabled to flow into the receiver 74. The leaves 
are discarded from the grid 72 prior to the aloin flowing from the leaf 
which would contaminate the gel within the receiver 74. 
The foregoing disclosure and description of the invention are illustrative 
and explanatory thereof, and various changes in the size, shape and 
materials, as well as in the details of the illustrated construction may 
be made without departing from the spirit of the invention.