Modern air-jet looms have become the fastest-growing type of shuttleless looms and the preferred type for textile enterprises to expand production scale because of their high speed, high quality, high efficiency and high automation monitoring level. In order to meet the needs of model selection, we have conducted research on four types of foreign jet looms on the market at present, Toyota JAT710 in Japan and Zax-N in Tsudaju, OMNI-plus in Pigano, Belgium and Mythos-TEC in Sumet, Italy. Through technical exchanges with manufacturers, we have also visited the manufacturers (Zax-N just produced, There is no user in China, only seen in the exhibition). The performance characteristics of the above four kinds of air-jet looms are understood. The following description is given.

1. On the opening mechanism, the positive opening mechanism is used in European air-jet looms.
apanese models have advantages in passive opening, such as Toyota and Tsudaku, which both produce passive opening cams themselves. Of course, they can also adopt active opening mechanism at the request of customers. At present, the active cam generally uses STAUBLI T1661, while the latest model of Shumet's Mythos-TEC air-jet loom uses FIMTEXTILE ME. Dobby machines generally use STAUBLI 2861 or 2871. 2871 is a high-speed dobby made by STAUBLI.

The disadvantage of active opening is that it is more expensive than passive opening. The energy consumption of air-jet loom is larger and the workload of variety modification is larger. Its advantages include weft insertion (more than 280 door width is obvious); weaving thick fabrics; motion precision of the heald frame is high and stable; active cam can be used for both positive and reverse weaving (asymmetric cam is not possible); and passive cam can not achieve the function of automatic leveling, automatic leveling is weaving twill or twill. When satin fabric is parked, the heald frames of each page can be automatically placed at the same height, thus greatly eliminating the tension difference of warp yarns, which is conducive to reducing the production of fabric parking gear.

Electronic dobby has more advantages than active cam. It not only eliminates the heavy work of overturning the cam, but also freely sets the angle of the flat heald. It can also arbitrarily set the motion mode of each weft heald frame, and can weave more complex pattern structure.

It is worth mentioning that both Toyota and Tsudaku have developed their own electronic opening devices. Compared with the electronic dobby, the electronic opening is a step forward in technology. The electronic opening is a servo motor controlled one page heald frame. It can not only freely set the movement mode of each page heald frame, but also freely set the heald time and static angle of each page heald frame, so the variety adaptability is greatly improved. Of course, electronic open air-jet looms are expensive, require high maintenance technology, and have high operating costs.

2. Weft insertion mechanism

Weft insertion mechanism is the most complex part of air-jet loom. In recent years, the technological progress of air-jet looms is the progress of electronic control technology, and the greatest progress of electronic control technology is weft insertion control technology.

The four kinds of air-jet looms mentioned in this paper can achieve 8-color weft selection, but at this time, due to the greatly reduced speed and the increased cost caused by the use of special reeds, their benefits are not superior to rapier looms, so it is rare to match more than 6-color weft selection in actual use.

Weft accumulator can be divided into two types: ordinary yarn type and yarn type (forced yarn feeding type). The former yarn is closely arranged, while the latter yarn has spacing, which avoids the intertwining between yarns. It is especially suitable for yarn weaving with long hairiness, such as wool yarn. Four kinds of air-jet looms can be equipped with these two kinds of weft accumulators, including OMNI-plus loom and automatic switching system of weft accumulator. When a weft accumulator fails to insert weft, it will automatically switch from two channels to single channel without stopping, which is very helpful to improve efficiency.

Nowadays, the speed of air-jet looms is getting higher and higher, and the weft insertion rate is getting higher and higher accordingly. In this case, it is necessary to install auxiliary main nozzles in air-jet looms. The function of auxiliary main nozzle is to accelerate the weft with lower air pressure, which can prevent the damage to the weft. Even under the condition of high speed or wide weaving, which is easy to cause weft burden, the weft breakage can be stabilized with less weft breakage. The auxiliary main nozzles of JAT710 and Zax-N are series horns, which realize high thrust weft insertion under low pressure.

OMNI-plus uses the "unit weft insertion system", which means that its main nozzle, auxiliary main nozzle, weft accumulator and so on are completely modular, can increase or decrease their number at any time and operate very simply, at the same time, maintenance is also very convenient, in the future upgrade to multi-color weft insertion is no longer troublesome.

All four models have weft brake devices, but the names of each are different. OMNI-plus is "programmed weft tension controller", JAT710 is "ABS", Zax-N is "WBS", Mythos-TEC is "electronic controlled weft tension device". The principle of these weft brake devices is basically the same. They all reduce the speed of weft at the end of weft insertion to reduce the huge instantaneous tension at sudden stop, thereby reducing the probability of weft breakage. The air-jet loom has obvious effect on high loom speed (800rpm) and wide loom, especially when the weft strength is low.

In order to reduce the air consumption, the number of secondary nozzles controlled by each auxiliary solenoid valve is relatively reduced. Mythos-TEC and MIN-PLUS have only two secondary nozzles controlled by one auxiliary solenoid valve. JAJAT710 is equipped with a small high sensitivity solenoid valve newly developed by Toyota Loom. The volume of the valve chamber is reduced by 85%, the power consumption is reduced by 15%, the reaction time is shortened by 50%, and the compressed air is eliminated.