Working principle of auxiliary nozzle

The position of the spray hole on the auxiliary nozzle is usually slightly concave, which can prevent the hair head of the spray hole from piercing or scraping the warp yarn. The included angle between the injection angle of the auxiliary nozzle and the main jet is small, about 9 °, which makes the change rate of the two jets after collision small, and can make full use of the air velocity after confluence. The auxiliary nozzle is fixed on the reed, and its spacing depends on the consumption of the main jet. Generally, it is thinner in the front and middle section near the main nozzle and denser in the rear section, which helps to maintain the high air velocity at the weft outlet and reduce weft shrinkage defects.

After using the auxiliary nozzle, the air consumption of air-jet weft insertion is greatly increased. In order to save compressed air, the way of grouping and sequential air supply is generally adopted as shown in the figure. Generally, 2 ~ 5 auxiliary nozzles are in a group, controlled by one valve, and each group is sprayed successively according to the direction of weft yarn. The valves controlling the main nozzle and auxiliary nozzle are solenoid valves, which are convenient to adjust the injection time and realize automatic control. The solenoid valve used in air-jet loom has the characteristics of high working frequency and fast response, so as to adapt to the high speed of loom.

A special auxiliary nozzle, also known as extension nozzle, is installed outside the outlet side of some air-jet looms. Its function is to stretch the weft at the end of weft insertion, which can effectively reduce the weft shrinkage defects of air-jet weft insertion.