In the energy-saving measures, in addition to the use of multiple air reservoirs and precision solenoid valve control, the use of various energy-saving and durable auxiliary nozzles has become one of the most important means. Therefore, the selection and use of various forms of auxiliary nozzles has become an important topic. The air-jet looms sold in the market mainly include European models, Japanese models and domestic models with foreign technology.
The auxiliary nozzles they use are generally divided into several categories:
European models: porous and special-shaped holes; The shape of the air tube is arc, and the surface is stainless steel natural color or titanium plating (golden yellow) on the surface. For example, the air-jet loom of donier company.
Asian Models: the shape of small hole and single hole gas pipes is square, and the surface is stainless steel natural color or surface oxidation treatment; For example: Tsuda Ju, Toyota's air-jet loom.
Take the auxiliary nozzle commonly used in ZA series air-jet loom of Tsudakoma company of Japan as an example. One is 1.5s, which is suitable for warp staple fabric and has long service life; Because the short fiber has small friction, round and thick head shape, large cross-sectional area, sufficient air flow and good fluidity, it has outstanding advantages and is widely used from the perspective of aerodynamics. One is 1.5f, which is suitable for warp short silk fabric. The nozzle head is sharp and thin, the cross-sectional area is small, and the spacing of auxiliary nozzles is mostly 80mm. This is because the filament has high strength, high friction and easy fuzzing. Therefore, this auxiliary nozzle must be used. In the south of China, the majority of users do not use this nozzle when weaving filament, resulting in a large number of defective fabrics. According to the experimental analysis from the dynamics, the air of this kind of nozzle is insufficient and needs a large pressure. In order to ensure the smooth weft insertion, the auxiliary nozzle spacing is generally 65 mm, which requires a greater air pressure. Therefore, the selection of different auxiliary nozzles for different varieties has a significant impact on the economic efficiency of textile mills.
The main brands of porous and special-shaped holes in Europe are Sulzer, bijiale, sumet, etc. the types of porous holes include 19 holes, 9 holes and 7 holes, as well as rectangular holes and five-star holes (very rare now).
The advantage of porous is that in the process of weft insertion, the gas flow is softer than that of single hole or porous, the air flow area is large, there is no excessive strain on the yarn, and the inclusion of the yarn is good, which makes the weft insertion more stable. This kind of nozzle is suitable for fabrics with weak yarn strength and elasticity. The disadvantage is that the small hole is blocked and needs to be cleaned every year, and the manufacturing cost is high and the gas consumption is high. The brands of small hole and single hole nozzles in Asia are: Tsuda Ju, Toyota, Nissan, Shuanglong, etc. The main types are double hole, single hole, single taper hole, eccentric taper hole and small diameter single hole (the hole diameter is less than 1.5mm).
The advantages of single hole mainly lie in high speed, good air clustering and low manufacturing cost. For example, the previous equipment of Toyota 600 was mostly double hole, but later it was changed to single hole. Its advantages are obvious, especially the speed advantage of conical hole nozzle. Moreover, Toyota 610, 710, Tsuda Zax series and Tsuda zax-n are the best series at present. The advantages of single hole nozzle are low gas consumption, low weaving cost and low manufacturing cost. The disadvantage is that the weft insertion is relatively porous, the air speed is relatively fast, the requirements for yarn are relatively high, the weft is easy to break, the inclusion of filament is poor, and the weft insertion is relatively porous and unstable.
Because the nozzle rubs with the yarn for a long time in the weaving process, especially the warp rubs the nozzle surface, the wear resistance of the nozzle directly affects the service life and indirectly affects the weaving. At the same time, in order to improve the service life of auxiliary nozzle and weaving efficiency and benefit under the condition of saving energy consumption, various air-jet loom manufacturers adopt different surface treatment methods, usually three kinds: stainless steel natural color, surface titanium plating and surface oxidation treatment.
There are many disputes about which way to adopt. Through analysis and test, it is considered that each has its own advantages and disadvantages, and each textile manufacturer will choose according to the actual situation in use. Generally speaking, Japanese and Chinese loom manufacturers pay attention to practicality, and it is common to adopt stainless steel natural color and nitriding; Most European machines adopt stainless steel natural color and titanium plating.
Due to the cross-section shape of the reed and the height of the air groove of the special-shaped reed on the air-jet loom, the auxiliary nozzle can only be inserted into the shed during weft insertion. The auxiliary nozzle must have the injection angle A and injection angle β, Because of the jet angle β Therefore, the auxiliary nozzle can only be inclined to the warp when entering and leaving the shed β The angle can not be parallel to the warp yarn, which tightens the warp yarn and intensifies the wear between the auxiliary nozzle and the warp yarn. The warp yarn will be ground and broken, the broken warp parking platform will increase, the operation efficiency will be reduced, and the auxiliary nozzle itself will accelerate the grinding of thread marks and shorten the service life. According to the damage data of the manufacturer, more than 90% of the auxiliary nozzles are scrapped in advance due to grinding line marks and cannot be used.
The innovative design of wear reducing auxiliary nozzle is characterized by moving the injection direction angle formed by the assembly of the original nozzle and round sleeve up to the head end of the nozzle, and directly pressing the injection direction angle on the plane. This ensures that the auxiliary nozzle can enter and exit the shed in parallel with the original thickness, reduces the wear with warp, improves product quality and weaving efficiency, and prolongs the service life of the auxiliary nozzle.
To sum up, for the application technology of auxiliary nozzle, it can be seen that the use of single hole auxiliary nozzle is more economical and practical than multi hole nozzle, and the compressed air energy is saved by 2%; However, it is unfavorable to weak yarn strength and weft insertion of elastic fabric. When weaving filament fabric, the use of 1.5f auxiliary nozzle can ensure the fabric quality, but the air pressure is 30% higher than that of 1.5s, and the air loss is about 15% higher than that of 1.5s. The energy-saving effect of antifriction auxiliary nozzle is relatively good. The auxiliary air supply pressure decreases by about 7% and the energy-saving is about 3%. In addition, when processing the auxiliary nozzle, the quality must be guaranteed and tested. Grouping according to the wind direction angle can save about 1% of energy.
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