Bottom rollers Fig. 4 Fluting of the bottom rollers; a) axial flutes, b) inclined flutes (spiral flutes), c) knurled fluting – Bottom rollers are made of steel and are mounted in roller stands or in the frame by means of needle, roller or ball bearings. They are positively driven from the main gear transmission or by a separate drive. In order to improve their ability to carry the fibers along, they are formed with flutes of one of the following types (see Fig. 4): axial flutes (a), inclined flutes (spiral flutes) (b), knurled fluting (c). Knurled fluting is used on rollers receiving aprons, to improve transfer of drive to the aprons. Other rollers have axial or, increasingly, spiral fluting. The latter gives quieter running and more even clamping of the fibers compared with axial fluting. Rolling of the top rollers on spiral flutes takes place in a more even manner and with less jerking. The diameter of the bottom rollers can lie in the range of 20 - 90 mm, but normally diameters between 25 and 50 mm are used. A drafting arrangement includes three to six such rollers. In long machines (e.g. ring spinning machines) the bottom rollers are made up by screwing together short lengths. Distances between the rollers of the drafting arrangement are usually adjustable and can then be adapted to the fiber lengths. One of the tasks of the drawframe is dust removal. Release of dust occurs almost exclusively in the drafting arrangement and this should be totally enclosed so that dust does not pass into the surrounding atmosphere. The dust-laden air must be extracted by suction (as shown in Fig. 10 for the Rieter machine). Each roller of the arrangement has an associated cleaning device (scraping bar and suction tube) so that fly and fibers tending to adhere to the rollers can also be carried away. In addition, on the Rieter drawframe the scraping bars are lifted from the intermittently. Trash collections therefore pass into the dust removal system. The air extracted is passed via tubes directly to filters within the machine and then into the exhaust ducts of the air-conditioning system or directly into those ducts. Filters within the machine are cleaned manually or by a wiper. This latter arrangement has the advantage not only of easier handling but also of constant suction pressure, resulting in constant cleaning efficiency.
Bottom rollers Fig. 4 – Fluting of the bottom rollers; a) axial flutes, b) inclined flutes (spiral flutes), c) knurled fluting Bottom rollers are made of steel and are mounted in roller stands or in the frame by means of needle, roller or ball bearings. They are positively driven from the main gear transmission or by a separate drive. In order to improve their ability to carry the fibers along, they are formed with flutes of one of the following types (see Fig. 4): axial flutes (a), inclined flutes (spiral flutes) (b), knurled fluting (c). Knurled fluting is used on rollers receiving aprons, to improve transfer of drive to the aprons. Other rollers have axial or, increasingly, spiral fluting. The latter gives quieter running and more even clamping of the fibers compared with axial fluting. Rolling of the top rollers on spiral flutes takes place in a more even manner and with less jerking. The diameter of the bottom rollers can lie in the range of 20 - 90 mm, but normally diameters between 25 and 50 mm are used. A drafting arrangement includes three to six such rollers. In long machines (e.g. ring spinning machines) the bottom rollers are made up by screwing together short lengths. Distances between the rollers of the drafting arrangement are usually adjustable and can then be adapted to the fiber lengths. One of the tasks of the drawframe is dust removal. Release of dust occurs almost exclusively in the drafting arrangement and this should be totally enclosed so that dust does not pass into the surrounding atmosphere. The dust-laden air must be extracted by suction (as shown in Fig. 10 for the Rieter machine). Each roller of the arrangement has an associated cleaning device (scraping bar and suction tube) so that fly and fibers tending to adhere to the rollers can also be carried away. In addition, on the Rieter drawframe the scraping bars are lifted from the intermittently. Trash collections therefore pass into the dust removal system. The air extracted is passed via tubes directly to filters within the machine and then into the exhaust ducts of the air-conditioning system or directly into those ducts. Filters within the machine are cleaned manually or by a wiper. This latter arrangement has the advantage not only of easier handling but also of constant suction pressure, resulting in constant cleaning efficiency.
draw_frame1.docx