Rieter

Operating principle

Index

Fig. 88 – Modern high-performance card

In modern installations, raw material is supplied via pipe ducting (Fig. 88, 1) into the  feed chute (of different designs) (2) of the card. An evenly compressed batt of about 500 - 900 ktex is formed in the chute. A transport roller (3) forwards this batt to the feed arrangement (4). This consists of a feed roller and a feeder plate designed to push the sheet of fiber slowly into the operating range of the licker-in (5) while maintaining optimal clamping.

The portion of the sheet projecting from the feed roller must be combed through and opened into tufts by the licker-in. These tufts are passed over grid equipment (6) and transferred to the  main cylinder (8). In moving past mote knives, grids, carding segments (6), etc., the material loses the majority of its impurities. Suction ducts (7) carry away the waste. The tufts themselves are carried along with the main cylinder and opened up into individual fibers between the cylinder and the flats in the actual carding process.

The flats (10) comprise 80 - 116 individual carding bars combined into a belt moving on an endless path. Nowadays some 30 - 46 (modern cards about 27) of the flats are located in the carding position relative to the main cylinder; the rest are on the return run. During this return, a cleaning unit (11) strips fibers, neps and foreign matter from the bars. Fixed  carding bars (9) and (12) are designed to assist the operation of the card.  Grids or cover plates (13) enclose the underside of the main cylinder. After the carding operation has been completed, the main cylinder carries along the fibers that are loose and lie parallel without hooks. However, in this condition the fibers do not form a transportable intermediate product. An additional cylinder, the doffer (14), is required for this purpose. The doffer combines the fibers into a web because of its substantially lower peripheral speed relative to the main cylinder.

A stripping device (15) draws the web from the  doffer. After calender rolls (16) have compressed the sliver to some extent, the coiler (18) deposits it in cans (17). The working rollers, cylinder and  flats are provided with clothing, which becomes worn during fiber processing, and these parts must be reground at regular intervals.