an apparatus for measuring the sub nozzle efficiency of
TRANSCRIPT
AN APPARATUS FOR MEASURING THE SUB-NOZZLE EFFICIENCY OF AIR-JET WEAVING MACHINE.
Authors: Magdi EI-Messiry & ShaimaaYoussef
Textile engg. Deptt., Alexandria university ,
Egypt
Indian journal of fiber & textile research.
Vol. 35, dec.-2010.
By: Utkarsh Solanki (M.E.-Part 1)
OUTLINE• AIRJET WEAVING LOOM
• Design of sub-nozzle
• Proposed Instrument principle to Measure Sub-nozzle and Main Nozzle Efficiency• Design parameters of the apparatus
• Procedure for measuring the nozzle
• Conclusion
AIRJET WEAVING LOOM Airjet loom is a very good alternative to other weft
insertion systems, but its major drawback is its high
power consumption due to compressed air.
Air-jet looms mostly used because of its
versatility and high productivity.
Due to substantial consumption of air and
compressor electricity, the airjet weaving machine
becomes more expensive.
Some parameters has to be study
intensively to overcome this disadvantage like,
a) Main nozzle shape,
b) Exit shape of sub-nozzle,
c) Response time of solenoid valve,
d) Sub-nozzle locations.
Continued..
Energy saving is the main aspect of air-jet loom.
Compressor consume 60-80% electricity of
air-jet loom.
Sub-nozzles use almost all of the air consumption
in the air-jet loom because of their number.
The purpose of this paper is to investigate the
sub-nozzle efficiency, so we can save the energy lost
in air-jet loom by using its different design and
apparatus for measuring the sub-nozzle efficiency.
Continued..
• AIRJET WEAVING LOOM
• Design of sub-nozzle
• Proposed Instrument principle to Measure Sub-nozzle and Main Nozzle Efficiency
• Design parameters of the apparatus• Procedure for measuring the nozzle
• Conclusion
Design of sub-nozzle
Sub-nozzles are arranged in a group of 4 or 5.
An electro-magnetic valve is attached to each group
and the sub- nozzle of the same group jet
simultaneously.
Air consumption was also reduced by 10 percent
by adopting solenoid valves for every two
sub-nozzles.
Figure 1. Design of few sub-nozzles
Continued..
There are different sub-nozzle designs with
rectangular hole, circular hole, elliptical hole,
multi holes, two vertical holes ,and tapered hole.
It has been found that sub-nozzle with multi
holes (19 holes) gives blowing angle stable at
different pressure levels with 15% higher weft
yarn insertion speed than single hole.
Continued..
Figure 2. New design of sub-nozzle
Tsudakoma Co patented a
new design of the sub-
nozzle in which the
interior is wider at one end
than the other.
The nozzle’s pulling force
is augmented by 30%,
and air consumption of the
main nozzle is reduced by
10% in comparison to the
cylindrical nozzle.
Continued..
Figure 3. Nozzle Inspector TR-7700
The TR-7700 Nozzle Inspector is a maintenance tool for ensuring higher efficiency of air-jet loom performance by setting sub-nozzles as per the visual data gathered on loom.
Variations in nozzle angles and air flow details can be compared between different sub-nozzles on the same or different looms, and this information can be used to correct these discrepancies.
Continued..
In an ideal case, flow through a perfect nozzle
would be reversible. For instance, without heat
transfer, frictional effect, and shocks and will therefore
be isentropic.
During the weaving process or loom maintenance
the holes in the sub-nozzles are subjected to be
blocked partially. A nozzle inspector needs to be sure
that the right value of air velocity will come at the pre-
determined pressure.
Continued..
• AIRJET WEAVING LOOM
• Design of sub-nozzle
• Proposed Instrument principle to Measure Sub-nozzle and Main Nozzle Efficiency
• Design parameters of the apparatus• Procedure for measuring the nozzle
• Conclusion
Proposed Instrument principle to Measure Sub-nozzle and Main Nozzle EfficiencyFigure 4.Schematic diagram of the apparatus used for measuring the efficiency of both sub-nozzle and main nozzle
The compressed air was supplied through
a pressure gauge from the compressor, air
receiver, and flow meter using a separate air
valve for each of sub-nozzle or main nozzle
to operate main nozzle or sub-nozzle
individually during the test.
To measure the efficiency of sub-nozzle
and main nozzle, an apparatus was
constructed using a scaled glass tunnel
which is held by a special attachment.
Continued..
When the air is connected to the nozzle,
the height of the plastic ball determines the
air flow rate. The value of the ball height
defines the condition of the nozzle and,
hence its efficiency.
In the case of measuring the efficiency
of sub-nozzle, a ball weighting 17.3g was
used, while in the case of measuring main
nozzle, a ball was weighting 60g because
the air flow coming of the main nozzle is
higher than that of the sub-nozzle.
SCALE
Continued..
• AIRJET WEAVING LOOM
• Design of sub-nozzle
• Proposed Instrument principle to Measure Sub-nozzle and Main Nozzle Efficiency
• Design parameters of the apparatus
• Procedure for measuring the nozzle
• Conclusion
Design parameters of the apparatus There are different sub-nozzles
with different shapes and hence, the
air velocity distribution from the
sub-nozzles also differs.
The position of the sub-nozzle in
the apparatus should be changed
according to the angle of the
confection of the air stream coming
from the sub-nozzle to enter the
edge of the glass tube. Figure 5. Principle for measuring sub-nozzle efficiency
The following equation are used to determine
the position of sub-nozzle in the apparatus:
D =D ball +4 mm
L= (D /2) / (tan(θ /2))where D ball is the diameter of ball ;
D is the diameter of glass tunnel ;
L= the distance between nozzle opening
and opening of glass tunnel ;
θ = the angle of the confection of air stream
coming from nozzle.
D
Continued..
• AIRJET WEAVING LOOM
• Design of sub-nozzle
• Proposed Instrument principle to Measure Sub-nozzle and Main Nozzle Efficiency
• Design parameters of the apparatus• Procedure for measuring the nozzle
• Conclusion
Procedure for measuring the nozzle
1.Adjust the position of the sub-nozzle and the
pressure gauge on the required air pressure.
2.Open the air-jet valve, put the ball in the air
stream inside the glass tunnel
3.Read the ball height from the scale on glass
tunnel
In a weaving mill random
samples of sub-nozzles
were tested on the designed
apparatus. The average
values of the floating ball
height (H) at different air
pressures are shown in Fig. 6
It is found that 19 holes
sub-nozzle gives less efficiency
than the single hole
either straight or inclined.
Figure 6. Comparison between different types of sub-nozzle at different values of the air pressure
Continued..
Figure 7 illustrates the testing
results of the main group
nozzle at the different air
pressure values.
The design of the suggested
apparatus is simple and
reliable and hence weaving
mills can use it to inspect the
nozzle’s efficiency on the
weaving machine, especially
after the maintenance or
when new nozzles are
supplied.
Figure 7. Effect of air pressure on the measuring ball height in the case of testing main nozzle
Continued..
The use of this apparatus assures that the
entire nozzles have the same efficiency
required for successful weaving at minimum
compressed air consumption.
Continued..
• AIRJET WEAVING LOOM
• Design of sub-nozzle
• Proposed Instrument principle to Measure Sub-nozzle and Main Nozzle Efficiency
• Design parameters of the apparatus• Procedure for measuring the nozzle
• Conclusion
ConclusionTo reduce the air consumption in airjet weaving,
the following subjects were studied: By measurement of dynamic air velocity found
that dynamic air velocity increases with time
(distance constant) and decreases with distance
from the nozzle.
By measurement of air flow velocity on the basis
of fluid dynamics each part of main nozzle with
help of pulls force formula found that decreasing
the diameter of the main nozzle can reduce energy
consumption; whereas increasing the length of the
thread tube can increase the pull force.
By studying the transonic/supersonic flow
analysis of main nozzle and shape they found
that the change in nozzle shape from the
square shaped needle end to the circular arc
causes static pressure to raise in the tube and
reduces total pressure losses in the nozzle.
For instance, air consumption can be
reduced slightly.
Continued..
By study of air consumption by single
nozzle design and performance analysis, the
found that the nozzle design has a great
influence on the flow characteristics at the
nozzle exit. The position of the yarn tube tip
relative to the entrance of the air tube
determines the amount of air flow through
the yarn tube. The yarn tube tip must be
placed at a position to create suction inside
the yarn tube. This makes the threading of
the yarn much easier.
Continued..
By study of flow characteristics of main nozzle
(by designing main nozzle, body, needle and
acceleration), they concluded that in order to
enhance the efficiency of the airjet in main
nozzle, the dimensions and harmony of the
needle tip, inner diameter, and length, among
other things, are very important.
From this study one can conclude that all
technological modifications can help to design
final main nozzle with minimum air
consumption.
Continued..
References1. Göktape. Ö. and Bozkan. O,, "Study on reduction of air consumption on air jet
weaving machine." Textile Research Journal, 78(9) :( 2008), p 816-824.
2. . T.H.OH, S.D.Kim. "A Numerical analysis of Transonic/supersonic flow in the Axisymmetric Main nozzle of an Air-jet loom." Textile Research Journal, 71(9): (September 2001), p 783-790
3. http://www.tsudkama.co.jp/textile/zax9100 (downloaded)
4. http://www.thaitakayamareed.co.th/tr_7700.html(downloaded)
5. https://en.wikipedia.org/wiki/Isentropic_process
6. Japan Machinery Federation Presidential Prize "Air Jet Loom that reduces compressed air consumption (ZAX9100." February 2006.