Mr. Akshay H. Bohara
Bohara Impex (Airjet Weaving Division), Ichalkaranji, INDIA
1. Introduction to Air Jet Weaving
|Optimization of Air Consumption of AirJet Weaving Machine|
2. Terms Related to Air Jet Weaving Technology
2.1 Air Index value
2.2 Arrival Time
2.4 Filling Stop
2.6 Spun Yarn
2.7 Yarn Hairiness
2.8 Yarn Package
3. Brief Description of Air Jet Weaving Process
|Filling feeding system|
Comparative power consumption figures for different types of shuttle less looms and the shuttle loom (for 190 cm width looms) are worked out (i.e. estimated) and are given in Table below.
Figures in Table are only for loom drive and do not include power requirement for humidification, lighting, etc.
4. Optimization of Compressed Air
- Firstly, by minimizing wasteful compressed air consumed i.e. by preventing compressed air leakages and,
- Secondly by improving the efficiency of compressors. Ways and means for both these aspects are discussed.
5. Preventing Air Leakages
Leakages usually occur in small openings; but the cumulative effect is great. Some tips for preventing the air leakage are given herewith.
- Standardise on good hose clamps.
- Inspect steam packing of valves in the system periodically, repack when necessary.
- Replace/repair leaky shut-off valves.
- Install condensate separators with automatic traps to eliminate the need for operators, opening the manual valve to clear water, thereby wasting air.
- Use good quality air hoses to avoid breaks and leaks.
- A 1/16” leak may cost $523, 6.49 CFM
- A 1/8” leak may cost $2,095, 26 CFM
- A 1/4” leak may cost $8,382, 104 CFM
6. Improving Volumetric Efficiency of Air Compressors
- Clogged air inlet filters.
- Obstruction at the inlet valve.
- Piston ring leakage.
- Hot inlet air.
- Inter cooler working inefficiently.
- Increase in impeller-diffuser clearance in case of centrifugal compressors.
7. Cost Reduction Opportunities
7.1 Air Intake
7.2 Compressor Motor Efficiency
Improvements in motor design have led to increased energy efficiency in motor operation. New motors that are suitable for textile manufacturing plants operate at an efficiency of 95%, comparing to motors designed 15 years ago at 90% or less. Over time, the efficiency of the motors may be reduced.
7.2.1 Compressor Controls
The highest efficiency is reached when the compressor is operating at 100% capacity.
7.3 Distribution Lines
7.4 Physical Properties and Characteristics of Yarn
7.5 Opening & closing timing of nozzle
7.6 Pressure on the nozzle
7.6.1 Setting of nozzle
|Setting of Nozzle|
- Distance between two nozzles: Improper setting between to relay nozzle will cause to variation in air pressure and will cause m/c performance to be in decreasing the air consumption will be unnecessary increases.
- Nozzle height: Proper height setting of relay nozzle will causes reduction in air pressure during weft insertion & air consumption can be reduced. Proper setting of the nozzle height will provide the uniform displacement of yarn during insertion.
- Nozzle angle: For uniform weft insertion of yarn during insertion proper nozzle angle will reduce air consumption. Pressure required for insertion can be reduced.
7.6.2 Multi hole versus single hole
|Multi-hole Nozzle Vs. Single-hole Nozzle
7.6.3 Different Hole patterns
|Types of Relay Nozzles 1.C Type 2.S Type 3.D type 4.B type.
7.6.4 Insertion time
7.6.5 Higher performance
|Air Consumption Vs. Yarn Speed|
7.6.6 DLC Coating
The D-type nozzles are exclusively coated with Diamond -Like carbon coating which is superior to any other coating. It increases life time up to 5 times and avoids wear and yarn cuts. DLC coating is therefore specially recommended for abrasive warp yarns.
7.6.7 Control of sub-nozzles
Control of sub-nozzles by increased groups conventionally, as in Fig. sub-nozzles are arranged in groups of 4 nozzles. An electro-magnetic valve is attached to each group and the sub-nozzles of the same group jet simultaneously.
8. Effect of costing
- 1 kwh = 5.5 Cfm
- 1kwh = Rs. 2.98
- 11 Cfm = Rs. 5.96/hr/loom
= Rs. 2574720/year/50 loom shed.
Thus a huge amount of capital can be saved just by proper setting of various machine parts without having any additional cost incurred.
- This shows that the weaving mills could obtain considerable saving in energy cost by just improving the work practices and by avoiding ignorance in settings.
- Reduction of air consumption by about Rs. 2574720/year/50 loom shed by achieving shortest possible blowing time of various nozzles, and optimizing this setting by trial and error method without affecting the performance of loom and quality of fabric can be achieved.
- Hence considerable saving in Energy cost can be achieved and Miracles can be created thus Investors can be boosted to move to Airjet technology resulting into new scale of measure of woven fabric production.
- Adanur, S., and Mohamed, M. H., Analysis of Air Flow in Air-Jet Filling Insertion, Text. Res. J., 61(5), 253-258 (1991).
- Adanur, S., and Bakhtiyarov, S., Analysis of Air Flow in Single Nozzle Air-Jet Filling Insertion: Corrugated Channel Model, Text. Res. J., 66(6), 401-406 (1996).
- Adanur, S., and Turel, T., Effects of Air and Yarn Characteristics in Air-Jet Filling Insertion Part II: Yarn Velocity Measurements with a Profiled Reed, Text. Res. J., 74(8), 657-661 (2004).
- Mohamed, M. H., and Salama, M., Mechanics of a Single Nozzle Air-Jet Filling Insertion System Part I: Nozzle Design and Performance, Text. Res. J., 56(11), 683-690 (1986).
- Ishida, T, “Air-Jet Loom, Present and Future, Part 5: Technical Problems Caused by Air-Jet”, JTN, November, 1982.
- Tarabadkar, S. A., Sharma, H. M., and Yadav, D. H., “Assessment of Compressed Air Requirement for Spinning and Weaving Machines”, Vol. XXXI, No. 3, The Bombay Textile Research Association, September, 2001.