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.