IMPROVEMENTS IN AND RELATING TO WOOL CARDING

Abstract: A wool card has at least one burr-beater morel unit (15a, 15b) for the removal of vegetable matter, the morel roller (16, 20) of which is fitted with a plurality of burr-beaters (30, 31), preferably two, arranged about the morel roller (16, 20) so that, in operation of the card, the fibre web is fed directly along the morel roller from one burr-beater (31) to the other (30) substantially without intervening inversion of the web or displacement of vegetable matter in the web.

Description: IMPROVEMENTS IN AND RELATING TO WOOL CARDING Field of the Invention 5 This invention is concerned with the carding of wool and is concerned in one aspect with modifications of a wool card to facilitate the operation of the card at a speed substantially higher than conventional card speed. Background Art 10 It has been proposed that worsted card productivity may be doubled or even tripled without detriment to sliver quality or card yield by simply substantially increasing the card speed above the conventional level (Gravolin et al, Proceedings of the Textile Institute Annual World Conference, Sydney, 1988, 15 "Doubling or Even Tripling Worsted Card Productivity"). Experimental work with existing commercial cards has, however, shown a difficulty with vegetable matter (VM) removal efficiency, a role typically played by a pair of burr-beater morel units. Attempts to re-establish the VM removal efficiency by speeding up the burr beaters to match the increased speed of the morels are often not feasible 20 because of inherent resonance related limitations on the speed of the burr- beaters. The natural conclusion from these experiments, taking into account the inherent limitations just mentioned, is that the morel units simply cannot operate as efficiently at the higher speeds. One might expect this from a consideration of the manner of operation of the morel units: the morel rollers have a very fine 25 surface mesh of a special configuration which accommodates the fibres of a web but not the vegetable matter. The vegetable matter is left exposed for dislodgement by the blades of hollow burr-beater cylinders rotating at high speed adjacent the mesh. French patent publication 2232626 discloses a VM removal unit in which 30 an enlarged morel roller accommodates a pair of burr-beaters separated by a reverse worker/ stripper carding unit which functions to invert the web on the SUBSTITUTE SHEET morel mesh to bring the shives and burrs which lie on the inside of the web at the first burr-beater to the outside of the web for dislodgement by the second burr- beater. Disclosure of the Invention It has been surprisingly found, in accordance with the invention, that enhanced vegetable matter removal efficiency can be obtained by fitting one or both morel units of a card with a pair of burr-beaters in which the web travels directly from one burr-beater to the other without intervening treatment by a worker/stripper carding unit. It has been further found that, contrary to the expectation that vegetable matter removal efficiency must inevitably deteriorate with substantial increases in card speed, the provision of such an arrangement results in the restoration of VM removal efficiency to a value close to the efficiency of conventional cards working at conventional card speeds. The invention accordingly provides a wool card having at least one and preferably two burr-beater morel units for the removal of vegetable matter, characterised in that the morel roller of said at least one unit, or one or each of said units, is fitted with a plurality of burr-beaters, preferably two, arranged about the morel roller so that the fibre web is fed directly along the morel roller from one burr-beater to the other substantially without intervening inversion of the web or displacement of vegetable matter therein. Preferably, the wool card further includes a swift and an associated double doffer arrangement including a pair of doffer rollers by means of which the fibre web is doffed from the card. The invention also provides a method of wool carding comprising directing a fibre web along a wool card which includes at least one burr-beater morel unit for the removal of vegetable matter, characterised in that the morel roller of said at least one burr-beater morel unit is fitted with a plurality of burr-beaters and in that said fibre web is fed directly along the morel roller from one burr-beater to the other substantially without intervening inversion of the web or displacement SUBSTITUTE SHEET of vegetable matter therein. The method preferably further includes doffing the fibre web from the card by double doffing the fibre web as two mats by means of a pair of doffer rollers associated with the swift of the card. Best Mode s) For Carrying Out the Invention The invention will now be further described, by way of example only, with reference to the accompanying drawing, which is a diagrammatic side elevation of a worsted card in accordance with the invention. The illustrated card 10 is of known general configuration and comprises a series of main cylinders including, in sequence, a licker 14, a breast 18, a first morel 16, a second morel 20 and a swift 22. The licker, breast and swift have the usual stripper /worker carding units 24 and doffing from the swift is achieved with a double doffer arrangement 26. The fibre web is fed along the sequence of cylinders, doffed as two mats by the successive doffer rollers 26a, 26b, and then converged from the double doffer by a cone (not shown) to form sliver. The double doffer, which is in contrast to the single doffer conventionally found on wool cards, is found to be necessary if adequate doffing efficiency is to be achieved at card speeds substantially above normal speeds. It has also been found that double doffing helps overcome problems arising from increased layer thickness or fibre density at higher card speeds, and enhances card production rate or transfer efficiency by 10 to 25% relative to single doffing. The morel rollers 16, 20 are respective components of a pair of vegetable matter removal units 15a, 15b which are depicted in a tandem configuration but may well be separated by one or more intervening rollers. Each morel roller is of conventional construction and has a cylindrical surface defined by a very fine mesh designed to accommodate the fibres of the web but to leave shives, burrs and other vegetable matter exposed. In conventional morels, a singe burr-beater 30a, 30b is disposed adjacent the surface mesh at the top of the roller and includes a longitudinally bladed hollow cylinder which rotates very rapidly and SUBSTITUTE SHEET acts to sweep the exposed vegetable matter into an adjacent tray for recovery and disposal. In accordance with the present invention, however, each unit 15a, 15b is fitted with a second burr-beater 31a, 31b located between the take-up point on the morel and the other burr-beater 30a, 30b. Most conveniently, the two burr-beaters 31a, 30a; 31b, 30b of each pair are of substantially conventional construction and are typically identical, including the usual longitudinally bladed hollow cylinder and an adjacent longitudinally extending tray. To physically accommodate the additional burr-beater, the morel rollers 16, 20 are typically made larger than is usual in current or previous carding practice, for example at least 450mm in diameter. It will be noted that the fibre web is fed directly along each morel roller 16, 20 from the first burr-beater 31a, 31b to the second 30a, 30b. No intervening provision is made to invert the web or otherwise displace the vegetable matter among the fibres, as in French patent publication 2232626, or indeed to modify the web in any way. Experiments have been conducted to ascertain the effect of a second burr- beater on the VM removal efficiency of a morel unit in a wool card operated at a card speed substantially above normal card speed. More specifically, a two swift Thibeau card was modified by substituting a 510 mm diameter morel roller for the roller of the second morel (normally 360 mm) and fitting two instead of one burr-beaters to this second morel. For the purposes of the experiment, the modified second morel was operated as a first morel by increasing the fibre loading to that of a normal first morel while disconnecting the first morel burr- beater. In a series of experiments, the morel roller was successfully operated at a normal speed of 95 m/min and at a substantially higher speed of 207 m/min. Two burr-beater speeds, 1200 and 2200 rpm were used. The results are summarised separately in Table 1 for shive and burr. SUBSTITUTE SHEET TABLE 1 Carding Conditions Double BB Morel The results demonstrate that the tandem burr beater pair maintains VM removal fairly constant in spite of large increases in card speed. It is thought that the second burr-beater of the pair is acting on surface vegetable matter missed by the first burr-beater, and that the expectation that failure to dislodge by one burr- beater will not be compensated for by a second burr-beater, is not supported by the results. The table also shows that the wool loss for the tandem burr-beaters is low and comparable to that of a morel after the first swift or licker. This suggests that wool loss should not be an impediment to operating tandem burr-beater pairs commercially. SUBSTITUTE SHEET

Claims: CLAIMS: 1. A wool card having at least one burr-beater morel unit for the removal of vegetable matter, characterised in that the morel roller of said at least one burr- beater morel unit is fitted with a plurality of burr-beaters, arranged about the morel roller so that, in operation of the card, the fibre web is fed directly along the morel roller from one burr-beater to the other substantially without intervening inversion of the web or displacement of vegetable matter therein. 2. A wool card according to claim 1 wherein said wool card has at least one further burr-beater morel unit. 3. A wool card according to claim 2 wherein said further burr-beater morel unit is also fitted with a plurality of burr-beaters arranged about the morel roller so that, in operation of the card, the fibre web is fed directly along the morel roller from one burr-beater to the other substantially without intervening inversion of the web or displacement of vegetable matter therein. 4. A wool card according to claim 3 wherein said burr-beater morel units fitted with a plurality of burr-beaters are arranged in tandem in the card. 5. A wool card according to any preceding claim wherein the or each burr- beater morel unit fitted with a plurality of burr-beaters is fitted with two burr- beaters. 6. A wool card according to any preceding claim further including a swift and an associated double doffer arrangement including a pair of doffer rollers by means of which the fibre web is doffed from the card. 7. A wool card according to any preceding claim wherein the morel roller of the or each burr-beater morel unit fitted with a plurality of burr-beaters is of diameter SUBSTITUTE SHEET at least 450 mm. 8. A method of wool carding comprising directing a fibre web along a wool card which includes at least one burr-beater morel unit for the removal of vegetable matter, characterised in that the morel roller of said at least one burr-beater morel unit is fitted with a plurality of burr-beaters, and in that said fibre web is fed directly along the morel roller from one burr-beater to the other substantially without intervening inversion of the web or displacement of vegetable matter therein. 9. A method according to claim 8 further comprising doffing the fibre web from the card by double doffing the fibre web as two mats by means of a pair of doffer rollers associated with the swift of the card. 10. A wool card substantially as hereinbefore described with reference to the drawing. 11. A method of wool carding substantially as hereinbefore described with reference to the drawing. SUBSTITUTE SHEET

Inventors: ATKINSON KENNETH ROSS, HARROWFIELD BARRY VALENTINE, ROBINSON GARY ALFRED, ATKINSON, KENNETH, ROSS, HARROWFIELD, BARRY, VALENTINE, ROBINSON, GARY, ALFRED
Applicants: COMMW SCIENT IND RES ORG, COMMONWEALTH SCIENTIFIC & INDUSTRIAL RESEARCH ORGA
Application year: 1990
Main classification: D01G15
IPC codes: D01G15