Method of blending textile fibers

Individual fiber components are blended in accordance with the properties of a required intermediate product such as a card sliver or an end product such as a yarn. The fiber bales are combined into component groups and the fiber components in the groups are accurately supplied by metering devices to a blender in which the components are uniformly mixed. The product from the blender may be cleaned and thereafter carded into a sliver. The characteristics of the sliver, such as the color, fiber, fineness and quantity, are tested and adjustments made in the blending in dependence upon any deviation from preset values for the characteristics.

This invention relates to a method of blending textile fibers. 
Heretofore, it has been known to process textile fibers by mixing the 
fibers from a plurality of bales in order to improve uniformity. In the 
past, several attempts have been made to mechanize the operation, such as 
described in U.S. Pat. Nos. 4,009,663 and 4,100,651. Generally, in 
conventional methods of blending, bales of varying origin are arranged in 
a row and are opened by an extraction device moving in reciprocation over 
them and extracting fiber flocks from the surface and transferring them to 
a conveying means. Alternatively, parts of bales are extracted manually or 
by machine and conveyed successively to a conveyor belt of an opening 
machine, in which the parts are opened to form fiber flocks and delivered 
to a conveying means. 
The conveying means can be mechanical or pneumatic and convey the flocks to 
"blending boxes" into which the fibers are poured and constitute a flock 
mixture. The fiber flock mixture from the blending boxes is then conveyed 
at varying speeds to a collective conveyor in order to obtain a folding 
effect, the aim being to homogenize the fiber flock mixture. Homogenizing 
devices for this are shown and described e.g. in German patent 
specifications 196 821 and 31 51 063. 
However, the aforementioned extraction and blending process has a 
disadvantage in that, since the rows of bales are stationary, the blend is 
unchangeable until the row has been finally extracted. Thus, the blending 
ratio remains the same during the whole time. The second extraction and 
blending process also increases the inaccuracy of the amount which has 
been extracted. 
Accordingly, it is an object of the invention to be able to quickly alter a 
fiber blending process to produce an accurate homogeneous fiber blend. 
It is another object of the invention to provide a relatively simple 
technique for controlling the quality of an end product produced from a 
plurality of fiber bales of different origin. 
It is another object of the invention to be able to control a fiber 
blending process in an automated manner to produce a quality product. 
Briefly, the invention provides a method of blending textile fibers which 
comprises the steps of extracting a fiber flock component from each of a 
plurality of fiber bales of varying origin and blending the fiber flock 
components from the fiber bales in controlled variable proportions to form 
a uniform blend. In accordance with the invention, a value of a 
characteristic of a product made from the uniform blend is measured and a 
deviation of the measured value from a pre-set value is obtained to 
immediately and automatically correct the blending of the fiber flock 
components in response to a deviation in order to eliminate the deviation 
in the product. This product may be an intermediate product such as a card 
sliver or an end product such as a yarn. 
The properties of the fiber of each bale may also be determined in advance 
by sample-taking from the bales. In this way, the fibers can be exactly 
blended in desired proportions to obtain the required properties of an 
intermediate product, such as a card sliver or an end product, such as a 
yarn.

Referring to FIG. 1, a plurality of conveyor belts 1 are arranged, as 
indicated, so as to convey a plurality of rows of fiber bales 2 of 
different origin to individual fiber extraction means 3. 
Each extraction means 3 moves on stationary rails disposed e.g., diagonally 
across the bales 2 on the conveyor belt 1. A device of this kind is known 
in principle from Swiss Patent No. 503 809. As a variant, use can be made 
of the device shown and described in Swiss Patent Application No. 
00399/88-8, where the extraction means 3 is movable up and down on an 
extraction device (not shown) movable in reciprocation on horizontal rails 
along the bales 2 and is obliquely adjustable for diagonal extraction. 
The extraction output can be controlled by varying the speed of the 
extraction means 3 along the diagonal path, or by varying the speed of 
advance of bales 2 by varying the speed of the individual conveyor belt 1. 
Each extraction means 3 extracts fiber flocks from a foremost bale 2 in 
each row via a drum to form a fiber flock component which is removed in 
known manner through a pneumatic conveying line 5 (not described here). 
The flocks are conveyed through the pneumatic line 5 to a blender 6, where 
they are mixed to form a uniform blend. 
The quantities conveyed to the blender 6 through the individual pneumatic 
conveying lines 5 will hereinafter be called "fiber flock components" or 
simply "components". 
The blenders 6 can be batch or continuous, depending on whether the 
aforementioned quantities are the weights of individual batches (kg) or 
the quantity travelling per unit time (kg/h). 
For simplicity, the conveying lines 5 in FIG. 1 are shown diagrammatically 
as opening directly into the likewise diagrammatic blender 6, but this can 
be different in practice, depending on the nature of the blender. For 
example, air-fiber separators can be used in order to separate each fiber 
and air mixture, so that the fiber flocks can fall freely into the blender 
6 whereas the air is discharged into an outgoing air duct. Separators of 
this kind are well-known in practice and are therefore not shown here 
separately. 
The quantities of the aforementioned individual flock components delivered 
to the blender 6 are controlled by a control system 7 in accordance with a 
control program. 
The control program can be a computer program comprising a 
component-blending program which can be adapted or altered for adaptation 
to alterations in the blend. 
Another variant would be a digital control system for each component, in, 
which the output of individual components can be chosen or altered by 
hand. 
The functions determining the extraction output of the components, e.g., 
the speed of advance of the respective conveyor belt 1 or the motion of 
the extraction means 3, are controlled by one or the other control system. 
Of course, the pneumatic conveying lines need not convey the extracted 
product directly to the blender; mechanical conveying elements such as 
conveyor belts can be inserted in between. In such cases, the fiber and 
air separators deliver the fiber product to the mechanical conveying 
elements. 
Each extraction means 3 is connected by a control line 8 and each conveyor 
belt 1 is connected by a control line 19 to the control system 7. 
The three control lines 67, 68, 81 entering the control system 7 will be 
described hereinafter. 
FIG. 2 shows a variant of FIG. 1, in which like components are given like 
reference numbers. In FIG. 2, the pneumatic conveying lines 5 convey the 
extracted fibers or fiber flocks (also called the product) not directly to 
the blender 6 but to component cells 9, from which the product is 
discharged by a discharge device 10 followed by a metering device 11 which 
delivers the product to the mixer 6. 
The discharge device 10, depending on its nature, may alternatively also be 
used for metering. 
The amount discharged from the individual component cells 9 is controlled 
by a control system 7.1 which actuates the individual metering devices 11 
or, in a variant, the discharge devices 10 via control lines 12. 
In the first-mentioned arrangement, the metering devices 11 can each be 
actuated by a control line 13 via the discharge devices 10 in order to 
co-ordinate the discharge with the metering. Alternatively, the discharge 
devices can be directly actuated by the control means 7.1. 
The component cells 9 are filled by elements 1 to 5 already mentioned in 
connection with FIG. 1. The use of two rows of bales, each with elements 1 
to 4, has been chosen by way of example only. In practice, a number of 
rows of bales or alternatively just a single row could be chosen per 
component cell 9. The decision depends on the number or blend of origins 
per row of bales which are to form a blend component to be supplied to a 
corresponding cell 9. 
The filling of the component cells 9 is controlled e.g., by a full-level 
indicator 14 and an empty-level indicator 15 provided in each cell via a 
control system 16. To this end, the control system 16 for reciprocating 
the extraction means 3 is connected by control lines 17 to each extraction 
means 3 and by control lines 18 to each motor driving the conveyor belts 
1. 
FIG. 3 shows another embodiment in which elements already shown and 
described in FIG. 2 are given the same reference numbers, i.e., bales 2, 
component cells 9, discharge devices 10, metering devices 11, blender 6, 
control system 7.1 and control lines 12 and 13. 
The bales 2 are in this case placed directly on the ground. As before, for 
the purpose of extraction, the bales 2 are divided into groups 
corresponding to the respective origin of the bales. Extraction is by 
means of a travelling extraction device 20 which moves along the groups of 
bales and extracts fibers or fiber flocks from the surface thereof. A 
device of this kind is known under the name "Unifloc" in the technical 
spinning sector and is sold throughout the world by Rieter Machine Ltd. 
The extraction device 20 conveys the extracted fibers in known manner 
through a pneumatic conveying line 21 to the corresponding component cells 
9. 
As already described in the case of FIG. 2, the component cells 9 comprise 
full-level indicators 14 and empty-level indicators 15 which deliver 
signals to a control system 22. This control system 22 is connected by a 
line 24 to the extraction device 20 and controls the extraction of fiber 
flocks from the corresponding groups of bales in order to fill the 
corresponding component cells 9. 
As diagrammatically indicated in FIG. 3, the extraction device 20 comprises 
an extraction means 23 known from Unifloc and comprises a rotating drum 
(not shown) which extracts fibers from the surface of the bales. 
In known manner also, the extraction means 22 can be rotated through 
180.degree. as marked by arrow M so that the extraction means 22 can open 
the group of bales 2 on the opposite side. In this manner, either one of 
the facing groups of bales can be used as a reserve group or, if the 
extraction device 20 rotates automatically as indicated hereinbefore, the 
two facing rows of bales can be alternately opened in preset manner. 
FIG. 4 shows a variant of FIG. 3, where components already described and 
shown in FIG. 3 are given the same reference numbers. 
The difference between FIGS. 3 and 4 is that instead of a single extraction 
means 20 for the entire device, one extraction device is provided for each 
of two facing groups of bales. 
Accordingly, the control system is denoted 22.1 instead of 22, since four 
individual extraction devices 20 are each separately controlled via a 
corresponding control line 24. Also, a pneumatic conveying line is 
provided for each extraction device 20; the line, which correspondingly is 
marked 21.1 instead of 21, opens into a respective component cell 9. 
FIG. 5 shows an arrangement similar to FIG. 1, but instead of the 
individual conveyor belt I per group of bales in FIG. 1, each group of 
bales has a conveyor belt 30 used for conveying only and a conveyor belt 
31 for conveying and weighing. 
The conveyor belt 31 can be used for weighing by having the shafts of the 
guide rollers of the conveyor belt 31 mounted on known pressure cells 32 
which each deliver a signal 33 corresponding to the weight, the signal 
being transmitted by a respective control line 33 to a signal-processing 
control system 7.2. The aforementioned signals are then processed in the 
the control system 7.2 which uses them to elaborate control signals which 
actuate the motors of the aforementioned conveyor belts 30, 31 via control 
lines 35 and also actuate the extraction means 3 via control lines 34. 
Of course, other weighing machines can be used and combined with conveyor 
belts. 
During operation, the control system 7.2 actuates the extraction means 3 
and the conveyor belts 30 and 31 at preset speeds in order to extract 
fiber flocks from bales 2 and convey the fiber flocks through pneumatic 
lines 5 to the blender 6. 
Each extraction means 3 for the individual groups of bales conveys a preset 
amount, controlled by the control system 7.2, to the blender 6. The preset 
extracted amount (kp/h) for each group of bales is monitored by the 
respective weighing conveyor belt 31 or by the pressure-cell weighing 
device 31 and is converted into signals and transmitted through lines 33 
to the control system. If the amount (kp/h) extracted per group of bales 
does not coincide with the preset amount, the control system adjusts the 
amount for extraction until the actual amount coincides with the preset 
amount. 
The measuring device 32 is used when the extraction means 3 is stationary 
for a brief moment at the turning-point in its reciprocating travel. 
In this method of extraction, the extraction means 3 always travels in 
reciprocation along the same path, substantially diagonally across the 
bale to be opened. The amount (kp/h) of fiber flocks extracted from the 
bales is determined by means of the speed of advance of the conveyor belts 
30, 31 and the extraction means 3. 
The control system 7.2 can be electronic and analog-based or can be a 
microprocessor by means of which the individual quantities extracted per 
group of bales can be set and adjusted by the signals from the control 
lines 33 and by input signals (explained hereinafter). 
FIGS. 6 and 7 show a weighing system similar to that of FIG. 5, FIG. 7 
being a plan view of FIG. 6 in the direction of arrow A. 
As can be seen in FIG. 7, a number of rows or groups of bales 2 are 
disposed side by side and each forms a blend component. As shown in FIG. 
6, each bale 2 rests on a conveyor belt 40 and an adjacent weighing 
conveyor belt 41. Each weighing conveyor belt 41, like the weighing 
conveyor belt 31 in FIG. 5, can be mounted on pressure cells 42, from 
which a signal corresponding to the weight is delivered by a control line 
43 to a control system 44. 
The fiber bales 2 on the weighing conveyor belt 41 are opened by an 
extraction device 48 according to Swiss Patent Application No. 00399/88-8, 
already mentioned in connection with FIG. 1. The main difference is that 
the extraction device 49 is long and extends over the preset number of 
rows of bales and comprises an extraction drum 51 which extracts fiber 
flocks simultaneously from all the predetermined rows of bales as shown in 
FIG. 7. 
Another difference between this method of extraction and that described in 
FIG. 1 is that the fiber extraction means 49 operates along an oblique 
track substantially corresponding to the diagonal across a preset number 
of adjacent fiber bales 2 in a line, e.g., four bales 2 as shown in FIGS. 
6 and 7. Of course, a different number of bales could be obliquely opened 
in the same manner, e.g., just a single bale as shown in FIGS. 1 and 2. 
Likewise, the possible length of the extraction means 49 determines the 
number of bales which can be lined up side by side in order to be opened 
simultaneously. 
The fiber material extracted by means 49 is conveyed along a pneumatic line 
50 which opens into a continuous blender 45. As described in the case of 
FIG. 1, line 50 can open into a previously-mentioned separator (not shown) 
which delivers the product to the blender 45. 
The speed of the extracting device 48 is also controlled by the control 
system 44 via line 46. 
Another control line 47 is provided for actuating the motors driving the 
guide rollers of the control belts 40 and 41. 
Of course, the guide rollers of the conveyor belts 40 and 41, not 
separately marked, for each group of bales have a separate drive motor, 
i.e., each motor has a separate control line 47 to the control system 44. 
During operation, the control system 44 controls the reciprocating motion 
of the extraction device 48 along the bales on the weighing and conveyor 
belt 41 nd the up and down motion of the extraction means 49 on device 48 
during the aforementioned reciprocating movement, so that the bales, as 
shown in FIG. 6, are opened in an inclined direction substantially 
corresponding to the diagonal across the four bales 2. 
The extraction motion is always along the same path and at a preset speed, 
so that the amounts extracted (kp/h) from the individual groups of fiber 
bales can be made different by individually adjusting the speeds of 
advance of the conveyor belts 40, 41. The different speeds of advance of 
the individual groups of bales correspond to an extraction program in 
which the amounts (kg/h) extracted from individual groups of bales vary in 
order to obtain the aforementioned blend. 
The motors driving the conveyor belts 40 and 41 are advantageously axial 
motors incorporated in the guide roller of the conveyor belts. Axial 
motors can be driven at varying frequency via frequency inverters, i.e., 
at varying speeds, this being a feature of the control system 44. 
The control system 44, as in all cases and especially mentioned in FIG. 5, 
can be analog or digital, for controlling the quantities of the individual 
components. If the individual quantities of components do not correspond 
to the set values they are corrected by signals from the pressure cells, 
which are transmitted through line 43 to the control system 44. 
FIG. 8 shows an extension of the previously described method, where the 
product leaving the blender 6 is delivered to a "cleaning station" 60 in 
which known cleaning machines are used. 
The cleaning station 60 can contain "coarse" cleaning machines 61 and 
"fine" cleaning machines 62. As before, the cleaning station is shown 
diagrammatically only. The same applied to a card 63 which follows the 
cleaning station 60 and can be a known card, e.g., card C4 sold throughout 
the world by Rieter Machine Ltd. The card 63 has a known control system 64 
which controls the carding operations and is adapted, inter alia, to 
ensure the uniformity and quantity (kp/h) of card sliver. 
After the card (relative to the belt conveying direction) and before the 
card sliver receiver (not shown), the characteristics of the sliver are 
measured to obtain a value thereof. For example, the card sliver is tested 
by a color sensor 65 and by a sensor 66 for measuring the fiber fineness. 
Both sensors or one or the other sensor can be used as required. 
In the case shown in FIG. 8, the color sensor 65 delivers a signal 
corresponding to the color of the sliver via a line 67, and the fiber 
fineness sensor 66 delivers a signal corresponding to fiber fineness via a 
line 68 to the control devices 7; 7.1; 7.2; 44 mentioned in conjunction 
with FIGS. 1 and 7 respectively controlling the individual fiber 
components. Another signal corresponding to the quantity of sliver (kg/h) 
is input by the card control system 64 via a line 81, likewise to the 
control systems 7; 7.1; 7.2; 44. These three signals are compared by the 
aforementioned control systems with the set values received in these 
control systems for, respectively, the sliver color, the fiber fineness 
and the output, so that any deviations therefrom during operation can be 
eliminated by varying the component mixture and the output. 
The product delivered by blender 6 is conveyed by a conveyor system to the 
cleaning station 60 and thence via a conveying system 70 to the card 63. 
These conveying systems can be mechanical or pneumatic. Conveying systems 
may also be disposed between fine cleaning machines and coarse cleaning 
machines. 
Likewise, the method is not restricted to a single cleaning station 60 and 
a single card 63 after the blender 6. A plurality of cleaning stations 60 
and a plurality of cards 63 behind the blender 6 can be supplied with the 
product from blender 6 or, if a single mixing station is provided after 
the blender 6, a plurality of cards 63 can be supplied with the product 
from the cleaning station 60. 
If a number of cards are provided, a color sensor 65 and/or a 
fiber-fineness sensor 66 can optionally be provided after each card, or 
alternatively, if a number of cards process the same product, the two 
lastmentioned sensors can be provided only for a "master" card. 
FIG. 9 illustrates the possibility of disposing the cleaning station 60 
between the fiber extractor and the component cells 9, so that the fiber 
material in the component cells 9 and available for blending is already 
clean. 
The device for conveying from the extraction device 20 to the cleaning 
station 60 is basically similar to the pneumatic conveying line 21, and in 
this case also the conveying means need not be pneumatic but can be 
mechanical. 
Likewise, the conveying means between the cleaning station 60 and the 
component cells 9 can also be a pneumatic conveying line, as marked at 21, 
but any conveying system can be used. 
Likewise, the cleaning station 60 is not restricted to a combination with 
the device in FIG. 3. Of course, the fiber components in all the 
arrangements shown in the drawings, except for FIGS. 6 and 7, can first be 
cleaned before reaching the blender 6. It is only a question of expense, 
since a separate cleaning station needs to be provided for each of the 
components in FIGS. 1, 2, 4 and 5. 
FIG. 10 shows a variant of the arrangement in FIG. 9, in which the cleaning 
station is divided into a coarse cleaning device comprising the cleaning 
machines 61 and a fine cleaning device comprising the fine cleaning 
machines 71, each being preceded by a storage container 72 (for simplicity 
only one is shown). 
The fine-cleaning machines 71 are started or stopped by a control system 
73, i.e., are stopped via an empty-level indicator 74 and started via a 
full-level indicator 75 (only one of each is shown). The full and 
empty-level indicators deliver signals through lines 76 and 77 to the 
control system 73. 
The coarse cleaning machines 61 are loaded by a fiber conveyor 78, which 
can be similar to the pneumatic conveying line 21 in FIG. 9 or any known 
fiber conveying means. The same applies to the means 79 for conveying 
fibers between the coarse cleaning machine 61 and the storage containers 
72. 
The fine cleaning machines deliver their products to a respective 
component-blend cell 9, as already described in connection with FIGS. 2-4 
and FIG. 9. 
Correspondingly, the other previously-described components are given the 
same reference numbers and not additionally described for FIG. 10. 
During operation, the components are individually cleaned and, accordingly, 
the empty-level indicators 15 for the individual component cells 9 cause 
fibers to be extracted from the corresponding bale group a or b or c or d, 
in order to clean the extracted fibers in the coarse-cleaning machine and 
deliver them to the corresponding storage container 72, which delivers the 
preset component to adjacent fine-cleaning machines 71. 
The product is demanded by the empty-level indicator 15 because the 
corresponding fine-cleaning machine does not continue to deliver the 
product, since the empty-level indicator 74 in the storage container 72 
has likewise indicated an empty level. Accordingly, the corresponding 
group a to d is opened until the corresponding full-level indicator 75 
indicates that the level of the extracted component is full. The 
corresponding fine-cleaning machine can then be restarted, until the 
full-level indicator 14 of the corresponding component cell 9 indicates a 
full level. 
The device for conveying fibers between the blender 6 and the card 63 can 
be similar to a fiber-conveying means marked 70 and described in FIG. 8. 
In this variant likewise, a blender 6 can serve a number of cards, so that 
the fiber-conveying means conveys the product from the blender to the 
corresponding number of cards. 
The invention thus provides a relatively simple method of blending fiber 
flocks from different fiber bales into a uniform blend and maintaining the 
blend during processing of the fiber flocks into a product such as a card 
sliver.