Title of Invention

AIR JET SPINNING MACHINE FOR PRODUCING SPUN THREADS FROM STAPLE FIBRE STRANDS

Abstract An air jet spinning machine for producing spun threads from staple fibre strands comprises a number of spinning positions, to each of which compressed air nozzles are arranged for the purpose of generating the spinning twist. A joint compressed air regulator is connected upstream of the spinning positions, which regulator comprises a pressure sensor and a regulating device. The compressed air regulator is set at a reference pressure, which corresponds to the unregulated static pressure, which prevails when all spinning positions are in operation. In the case of a change in the static pressure, the compressed air regulator re-adjusts to the reference pressure.
Full Text DE 10 2004 052 510.2 2
BACKGROUND AND SUMMARY OF THE INVENTION
Air jet spinning machine
The present invention relates to an air jet spinning machine for producing spun
threads from staple fibre strands, comprising a number of spinning positions, to each
of which compressed air nozzles are arranged for the purpose of generating the
spinning twist, also comprising a joint compressed air regulator connected upstream
of the spinning positions, said regulator comprising a pressure sensor and a
regulating device for adjusting the measured static pressure.
An air jet spinning machine is known from German published patent application DE
38 36 481 C2, on which the preamble of the present invention is based, and which
discloses a compressed air regulator which reacts to changes in the constantly
monitored spinning tension. In one variation an attempt is made to keep the spinning
tension constant in that the pressure acting on the compressed air nozzles is
correspondingly adjusted. For this purpose a pressure sensor is arranged to the
compressed air regulator, which transfers the measured data to a control system for
analysis. The control system comprises a regulating device for changing the
respective pressure.
In the case of the air jet spinning machines according to the present invention, the
problem is somewhat different, as it is not provided that the pressure on hand at the
compressed air nozzles is adjusted at any one time to the monitored spinning twist.
Rather, a solution is sought in which the static pressure acting on the compressed air
inlet of a longer air jet spinning machine is independent of how many spinning
positions are operational at any one time. The operational pressure of the spinning
mill, namely that which is considered to be constant, prevails at the compressed air
inlet of an air jet spinning machine and measures as a rule 6 bar. If, however, all
spinning positions are in operation, the static pressure can fall below 5 bar. If only a
number of the spinning positions are in operation, the drop in static pressure is
correspondingly lower. The latter is for example the case when the air jet spinning
machine is starting up, or when several spinning positions are temporarily not in
operation due to an end break. 2

DE 10 2004 052 510.2 3
It is an object of the present invention to permanently maintain a constant level of
static pressure independently of how many spinning positions of an air jet spinning
machine are in operation.
This object has been achieved in accordance with the present invention in that the
compressed air regulator is set at a reference pressure, which corresponds to the
unregulated static pressure which prevails when all the spinning positions are in
operation, and in that the compressed air regulator re-adjusts to the reference
pressure when a change in the static pressure occurs.
According to the invention, the compressed air regulator, which comprises a
compressed air sensor and a regulating device, is designed as a true actuator, by
means of which the static pressure at the compressed air inlet of the air jet spinning
machine is kept constant. If, for example, a number of spinning positions fail,
resulting in an increase in the static pressure, the compressed air regulator adjusts
the static pressure back down to the level of the reference pressure. When the
stopped spinning positions are subsequently put into operation again, the
downwardly adjusted pressure drops again, but is adjusted upwards again to the
level of the reference pressure by the compressed air regulator.
The reference pressure cannot of course be greater than the lowest unregulated
level of static pressure occurring when all the spinning positions of an air jet spinning
machine are in operation. It is, however, by all means possible to choose the
reference pressure at a lower level than that of the above mentioned static pressure.
In an embodiment of the present invention it is provided that the chosen reference
pressure is lower than the unregulated static pressure when all spinning positions are
in operation. A lower level reference pressure is by all means possible within certain
limits and has the advantage in that the static pressure can always be adjusted
upwards and also downwards. This "pressure play" permits for example not only the
static pressure to be kept constant, but also permits variations in the yarn twist within
certain limits at a pre-determined draw-off speed of the spun thread.
BRIEF DESCRIPTION OF THE DRAWINGS
These and further objects, features and advantages of the present invention will
become more readily apparent from the following detailed description thereof when
taken in conjunction with the accompanying drawings wherein:
3

DE 10 2004 052 510.2 4
Figure 1 shows a diagram to demonstrate the dependence of the static pressure
prevailing at the compressed air inlet of the air jet spinning machine from the number
of the spinning positions in operation,
Figure 2 shows in a very schematic representation the provided joint compressed air
regulator for a number of spinning positions,
An air jet spinning machine comprises a number of spinning positions, of which only
two spinning positions 1 and 2 are schematically shown in Figure 2. Each spinning
position 1, 2 serves to produce a spun thread 3 from a staple fibre strand 4.
A spinning position 1, 2 comprises as essential components a drafting device 5, of
which only one delivery roller pair 6 bordering the drafting zone is shown, further an
air jet aggregate 7, a draw-off roller pair 8 and a winding device (not shown).
The staple fibre stand 4 fed in feed direction A is drafted in the respective drafting
device 5 to the desired degree of fineness. The thread 3 drawn off in draw-off
direction B receives in the respective air jet aggregate 7 its spinning twist. A number
of compressed air nozzles 9 are arranged for this purpose to the individual air jet
aggregates 7, as is known in many cases from prior art, so that the spinning process
itself need not be described in any detail. The individual compressed air nozzles 9
extend out advantageously from an annular space 10, whereby the annular spaces
10 of all air jet aggregates 7 are connected to a joint compressed air conduit 11
located upstream. This compressed air conduit 11 receives the operational pressure
installed in the respective spinning mill of for example 6 bar and can be seen as a
type of accumulator for the air jet spinning machine.
The static pressure prevailing at the compressed air inlet of the air jet spinning
machine is now dependent of the number of spinning positions 1, 2 ... of the air jet
spinning machine currently in operation. If only a few spinning positions 1, 2 ... are in
operation, then the static pressure present in the compressed air conduit can be
approximately equated with the operational pressure installed in the spinning mill. If,
however, all available spinning positions 1, 2 ... of the air jet spinning machine are in
operation, then the static pressure at the compressed air inlet of the air jet spinning
machine drops significantly, in certain circumstances by more than 1 bar. It is evident
that as a result, the intensity of the spinning twist of the individual threads 3, and
4

DE 10 2004 052 510.2 5
therefore the quality of the thread, varies. The present invention seeks to avoid this
situation.
The above mentioned problem is shown in Figure 1 in the form of a diagram, in which
the abscissa lists the number z of spinning positions 1,2... in operation at a given
time, while the ordinate lists the respective prevailing static pressure ps.
It can be seen with the aid of Figure 1 that when none of the spinning positions 1, 2
... is in operation, a static pressure p0 prevails at the compressed air inlet of the air
jet spinning machine. When, however, all spinning positions 1, 2 ..., in this case for
example 200 positions, are in operation, the static pressure drops to a value of pu.
Depending on the number of spinning positions 1, 2 ... in operation, a static pressure
prevails which lies between the uppermost pressure p0 and the lowest pressure pu.
In order to avoid this, measures are taken in accordance with the present invention
so that the prevailing static pressure ps remains constant during all operational states
of the air jet spinning machine.
For a number of spinning positions 1,2..., either for all spinning positions 1, 2 ... of
an air jet spinning machine or for only a pre-determined number of spinning positions
1,2 ... of a machine section, a joint compressed air regulator, connected upstream, is
provided which keeps the static pressure ps constant. For this purpose the
compressed air regulator is set at a so-called reference pressure pR. As shown
clearly in Figure 1, this reference pressure pRmust not be greater than the static
pressure pu described above. The reference pressure PR can, however, be
somewhat less than the pressure pu. In any case, the reference pressure pR
corresponds to that unregulated static pressure pu when all spinning positions 1, 2 ...
are in operation.
The compressed air regulator comprises a pressure sensor 12, for measuring the
overall prevailing static pressure at the compressed air inlet of the air jet spinning
machine or machine section, and a regulating device 13. The latter acts on a choke
valve 14 of the compressed air conduit 11. The compressed air regulator can
therefore constantly re-adjust to the reference pR in the case of a change in the static
pressure ps in the way described above. If, for example, a number of spinning
positions 1, 2 fail, the static pressure ps measured by the pressure sensor 12
increases. In this case, the reference pressure PR is immediately re-adjusted via the
5

DE 10 2004 052 510.2 6
regulating device 13 and the choke valve 14. In the reverse case, when previously
stopped spinning positions 1,2 ... are again in operation, the downwardly adjusted
pressure drops again, but is re-adjusted upwards again to the reference pressure pR.
The reference pressure pR can if required be equal to the static pressure pu. If the
reference pressure pR is set at a somewhat lower level, than a certain tolerance for
the regulation process exists, which tolerances range not only upwards but also
downwards. This can be used to advantage in that the spinning twist imparted to the
thread 3 can be varied within certain limits.
For the sake of clarity it is mentioned at this point that when the air jet spinning
machine is at a complete standstill, the regulation process is shut down and the
compressed air is shut off.
6

DE 10 2004 052 510.2 7
CLAIMS:
1. Air jet spinning machine for producing spun threads (3) from staple fibre
strands (4), comprising a number of spinning positions (1, 2 ...), to each of
which compressed air nozzles (9) are arranged for the purpose of generating
the spinning twist, also comprising a joint compressed air regulator connected
upstream of the spinning positions, said regulator comprising a pressure
sensor (12) and a regulating device (13) for adjusting the static pressure
(ps), characterized in that the compressed air regulator (12,13) is set at a
reference pressure (pR), which corresponds to the unregulated static pressure
(pu) which prevails when all spinning positions (1, 2 ...) are in operation, and
in that the compressed air regulator (12, 13) re-adjusts to the reference
pressure (pR) in the case of a change in the static pressure (ps).
2. Air jet spinning machine according to claim 1, characterized in that the
chosen reference pressure (pR) is less than that of the unregulated static
pressure (pu) when all the spinning positions (1, 2 ... ) are in operation.
7

An air jet spinning machine for producing spun threads from staple fibre strands
comprises a number of spinning positions, to each of which compressed air nozzles
are arranged for the purpose of generating the spinning twist. A joint compressed air
regulator is connected upstream of the spinning positions, which regulator comprises
a pressure sensor and a regulating device. The compressed air regulator is set at a
reference pressure, which corresponds to the unregulated static pressure, which
prevails when all spinning positions are in operation. In the case of a change in the
static pressure, the compressed air regulator re-adjusts to the reference pressure.

Documents:

01052-kolnp-2007-abstract.pdf

01052-kolnp-2007-claims.pdf

01052-kolnp-2007-correspondence others 1.1.pdf

01052-kolnp-2007-correspondence others 1.2.pdf

01052-kolnp-2007-correspondence others 1.3.pdf

01052-kolnp-2007-correspondence others.pdf

01052-kolnp-2007-description complete.pdf

01052-kolnp-2007-drawings.pdf

01052-kolnp-2007-form 1.pdf

01052-kolnp-2007-form 2.pdf

01052-kolnp-2007-form 3.pdf

01052-kolnp-2007-form 5.pdf

01052-kolnp-2007-gfa.pdf

01052-kolnp-2007-international publication.pdf

01052-kolnp-2007-international search report.pdf

01052-kolnp-2007-pct others.pdf

01052-kolnp-2007-pct request form.pdf

01052-kolnp-2007-priority document.pdf

1052-KOLNP-2007-ABSTRACT 1.1.pdf

1052-KOLNP-2007-AMANDED CLAIMS.pdf

1052-KOLNP-2007-CANCELLED PAGES.pdf

1052-KOLNP-2007-CORRESPONDENCE.1.3.pdf

1052-KOLNP-2007-CORRESPONDENCE.pdf

1052-KOLNP-2007-DESCRIPTION (COMPLETE) 1.1.pdf

1052-KOLNP-2007-ENGLISH TRANSLATION.pdf

1052-KOLNP-2007-EXAMINATION REPORT.1.3.pdf

1052-KOLNP-2007-FORM 1.1.pdf

1052-KOLNP-2007-FORM 18.1.3.pdf

1052-KOLNP-2007-FORM 2.1.pdf

1052-KOLNP-2007-FORM 26.1.3.pdf

1052-KOLNP-2007-FORM 3.1.3.pdf

1052-KOLNP-2007-FORM 3.1.pdf

1052-KOLNP-2007-FORM 5.1.3.pdf

1052-KOLNP-2007-FORM-27.pdf

1052-KOLNP-2007-GRANTED-ABSTRACT.pdf

1052-KOLNP-2007-GRANTED-CLAIMS.pdf

1052-KOLNP-2007-GRANTED-DESCRIPTION (COMPLETE).pdf

1052-KOLNP-2007-GRANTED-DRAWINGS.pdf

1052-KOLNP-2007-GRANTED-FORM 1.pdf

1052-KOLNP-2007-GRANTED-FORM 2.pdf

1052-KOLNP-2007-GRANTED-LETTER PATENT.pdf

1052-KOLNP-2007-GRANTED-SPECIFICATION.pdf

1052-KOLNP-2007-OTHERS.1.3.pdf

1052-KOLNP-2007-OTHERS.pdf

1052-KOLNP-2007-PETETION UNDER RULE 137.pdf

1052-KOLNP-2007-REPLY TO EXAMINATION REPORT.1.3.pdf

1052-KOLNP-2007-REPLY TO EXAMINATION REPORT.pdf


Patent Number 247476
Indian Patent Application Number 1052/KOLNP/2007
PG Journal Number 15/2011
Publication Date 15-Apr-2011
Grant Date 11-Apr-2011
Date of Filing 26-Mar-2007
Name of Patentee MASCHINENFABRIK RIETER AG
Applicant Address KLOSTERSTRASSE 20 CH 8406 WINTERTHUR SWITZERLAND
Inventors:
# Inventor's Name Inventor's Address
1 SCHAFFLER, GERNOT NARZISSENWEG 4, 73116 WASCHENBEUREN GERMANY
PCT International Classification Number D01H 4/02
PCT International Application Number PCT/EP2005/011193
PCT International Filing date 2005-10-18
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10 2004 052 510.2 2004-10-21 Germany