Title:
Apparatus for sequentially evacuating and impregnating a textile web
United States Patent 3881445


Abstract:
Apparatus for sequentially evacuating and impregnating a textile web has a vacuum chamber leading directly into an impregnation vessel. The chamber is formed only by opposed sets of rollers mounted between opposed side walls, the adjacent rollers in each set being in sealing contact and the side walls sealingly contacting the adjacent end faces of the rollers. The rollers define a hollow evacuable space and opposed pairs of rollers at each end of the sets provide inlet and outlet roller pairs for moving a textile web in longitudinal movement through the vacuum chamber. The outlet rollers also form with the side walls the bottom of the impregnation vessel which is an open-topped trough the sides of which are formed by portions of large diameter intermediate rollers between which the outlet rollers are disposed. The rollers and side walls are movably mounted and a control system adjusts the sealing forces between contacting surfaces.



Inventors:
NOTHIGER OTTO
Application Number:
05/400092
Publication Date:
05/06/1975
Filing Date:
09/24/1973
Assignee:
CIBA-GEIGY CORPORATION
Primary Class:
Other Classes:
68/22B, 118/50, 118/405
International Classes:
D06B1/00; D06B1/14; D06B5/02; (IPC1-7): B05C3/12
Field of Search:
118/405,50,419-420,414,4 117
View Patent Images:



Primary Examiner:
Feldbaum, Ronald
Claims:
What is claimed is

1. An apparatus for the sequential evacuation and impregnation of a textile web, including:

2. An apparatus as claimed in claim 1, wherein each set of rollers includes an intermediate roller sealingly contacting said second, outlet roller of the set and having a diameter greater than said second roller, the axes of said outlet rollers and said intermediate rollers being in a common plane, portions of said intermediate rollers external of said vacuum chamber cooperating with said side walls to provide a further part of said impregnation vessel, said impregnation vessel being in the form of an open-topped trough the nip between said outlet rollers being at the bottom of the trough and said external surface portions of said intermediate rollers providing said portions of the trough.

3. An apparatus as claimed in claim 1, wherein said control means includes a jack mechanism coupled to each movable roller and to said side wall member to effect the controlled movement thereof, each jack mechanism being a hydraulic or pneumatic jack having a double-acting piston.

4. An apparatus as claimed in claim 2, wherein each roller in said sets is journalled in bearings movable in a direction transverse to the roller axis whereby the sealing forces between adjacent rollers are adjustable, and each side wall comprises a member movably mounted for movement in the direction of the roller axis whereby the sealing forces between each side wall member and the adjacent end faces of said rollers is adjustable, the apparatus further comprising control means being responsive to the pressure in said vacuum chamber to adjust the aforementioned sealing forces in dependence thereon.

Description:
BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to apparatus for the sequential evacuation and impregnation of a textile web. The evacuation and impregnation are carried out by moving the web longitudinally through a vacuum chamber and then through an impregnation vessel.

2. Description of the Prior Art

A known apparatus is described in British Pat. Specification 1,246,806. That specification describes a vacuum chamber with two superjacently disposed horizontally extending pairs of rollers. The two rollers of each pair roll sealingly upon each other and transport the textile web between them. The two end faces of each roller bear sealingly on the chamber walls. A sealing flap bears on each roller on the top of the upper roller pair as well as on the bottom of the lower roller pair, the sealing flaps being sealingly connected to the walls of the vacuum chamber. The vacuum chamber is therefore enclosed on all sides through its walls, the sealing flaps and the rollers. The walls of the vacuum chamber are slightly extended above the upper roller pair to form a trough for dye liquor or impregnating liquid. The bottom of the trough is formed directly by the sealing flaps and the roller pair.

In this prior apparatus the textile web which is to be treated is introduced into the vacuum chamber from below between the two lower rollers and passes through the chamber and out via the two upper rollers directly into the liquor bath. Despite its advantages in terms of process technology the apparatus has practical difficulties in ensuring that the sealing flaps provide a satisfactory sealing action in order to enable a sufficient vacuum to be obtained in the vacuum chamber.

SUMMARY OF THE INVENTION

It is an object of the invention to provide an apparatus having a sequential vacuum chamber and impregnation vessel for treating a textile web, in which the vacuum chamber does not rely on the sealing action of sealing flaps contacting rollers.

The present invention now provides apparatus for the sequential evacuation and impregnation of a textile web, including:

A VACUUM CHAMBER DEFINED BY A PAIR OF OPPOSED SIDE WALLS AND FIRST AND SECOND SETS OF ROLLERS DISPOSED BETWEEN SAID SIDE WALLS WITH THE END FACES OF EACH ROLLER IN SEALING RELATIONSHIP WITH RESPECTIVE ONES OF SAID SIDE WALLS AND IN EACH SET ADJACENT ROLLERS BEING IN SEALING CONTACT WITH ONE ANOTHER, FIRST AND SECOND ROLLERS OF SAID FIRST SET BEING DISPOSED ADJACENT FIRST AND SECOND ROLLERS, RESPECTIVELY, OF SAID SECOND SET TO PROVIDE, RESPECTIVELY, INLET AND OUTLET PAIRS OF ROLLERS FOR GUIDING A TEXTILE WEB INTO AND OUT OF, RESPECTIVELY, SAID VACUUM CHAMBER, AND AT LEAST ONE ROLLER OF SAID SETS BEING ARRANGED AS A DRIVEN ROLLER FOR LONGITUDINALLY MOVING A TEXTILE WEB THROUGH SAID VACUUM CHAMBER; AND

AN IMPREGNATION VESSEL AT LEAST PARTIALLY DEFINED BY SURFACE PORTIONS OF SAID PAIR OF OUTLET ROLLERS EXTERNAL OF SAID VACUUM CHAMBER AND ADJACENT PORTIONS OF SAID SIDE WALLS WHEREBY A TEXTILE WEB LEAVING THE NIP OF SAID OUTLET ROLLERS PASSES INTO SAID IMPREGNATION VESSEL.

The two sets of rollers can be regarded as providing transverse side walls of the vacuum chamber between the aforementioned side walls, the transverse walls extending longitudinally from the inlet to the outlet of the chamber so that additional sealing flaps are not required. In a preferred form of apparatus the outlet rollers are directly above the inlet rollers, the two sets of rollers being disposed symmetrically about a vertical plane. The impregnation vessel is in the form of an open-topped trough the nip of the outlet rollers being at the bottom of the trough and side portions of the trough being formed by an external surface portion of a respective intermediate roller in each set and the aforementioned side walls. To this end these intermediate rollers which sealingly contact respective ones of the outlet rollers have a greater diameter than the outlet rollers and have their axes in the same plane as the outlet rollers.

Provision is made in the preferred apparatus for adjusting the sealing forces between rollers and between the side walls and the end faces of the rollers so that the desired degree of vacuum is obtained without excessive friction and wear.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention and its preferred practice may be better understood an embodiment of it will now be described with reference to the accompanying drawings in which:

FIG. 1 is a diagrammatic side view of the apparatus from which bearings, drives, feed devices and the like have been omitted; and

FIG. 2 is also a diagrammatic drawing and is a view from below of a part of the apparatus illustrating the control system for one side wall and two rollers.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The apparatus of FIG. 1 comprises a vacuum chamber 5 comprised of a pair of parallel side walls or plates 6 (only the front one of which is seen in FIG. 1) between which are mounted first and second sets of rollers with their axes normal to the walls 6. Each set comprises three rollers 1, 3 and 4 and the two sets are arranged symmetrically on each side of the vertical path of movement of a textile web 2 which is to be treated. The roller (i.e. cylindrical) surfaces of adjacent rollers in each set are in sealing contact, though as will be described later the contact force between the rollers is adjustable. The rollers 1 cooperate to provide an inlet pair of rollers between the nip of which the textile web 2 is guided into the vacuum chamber. The intermediate rollers 3 are spaced from the web 2 which leaves the vacuum chamber by passing between the nip of the rollers 4 which thus provide a pair of outlet rollers from the chamber. The axes of rollers 4, which are disposed between the intermediate rollers 3, lie in the same plane as the axes of rollers 3, the latter having a substantially greater diameter than rollers 4. The plates 6 bear in a sealing fashion against respective end faces of each roller so that the hollow space within the sets of rollers is evacuable by means not shown in FIG. 1 to evacuate the web 2 as it is longitudinally moved through the vacuum chamber in an upward direction. At least one of the rollers is arranged to be driven.

The plates 6 substantially project above the outlet rollers 4, as do the rollers 3, so as to form with portions of the surfaces of the rollers 4 and the intermediate rollers 3 which are external of the vacuum chamber, an impregnation vessel in the form of a trough 7 which is open at the top and in which an impregnating liquid is received. Thus on leaving the vacuum chamber through the nip of rollers 4 the moving web passes straight into the bottom of trough 7 and through the impregnating liquid in the trough. The outlet rollers 4 and the intermediate rollers 3 are supported in movable journal bearings so as to be slidable relative to each other in the common plane of their axes as indicated by the double-headed arrows marked thereon, while the inlet rollers 1 are supported in movable bearings so as to be slidable at an angle with respect to their respective adjacent rollers, as indicated by the double-headed arrows marked on rollers 1. The plates 6 are supported so as to be slidable in the axial direction of the rollers.

To ensure that the rollers bear sealingly upon each other and that the plates bear sealingly upon the rollers, a control system designated generally by the reference numeral 8 is provided as is illustrated in FIG. 2. The control system comprises a control unit 11 and a plurality of hydraulic (or pneumatic) jacks 10 which are controlled by the afore-mentioned control unit. The jacks are of the kind having double-acting pistons in the jack cylinders. The jacks 10 act on the slidable journal bearings of the rollers 1 and 3 as well as on the slidable plates 6. A pressure-sensing device 9, which projects into the vacuum chamber 5, detects the negative pressure which is established in the said chamber (approximately 0.25 atm abs or less in operation) and transmits this value to the control unit 11 which regulates the contact pressure between the rollers or between the plates and the rollers via the jacks 10 in dependence upon the afore-mentioned value. It is of course also possible to provide separate control units for regulating the contact pressure between rollers and between rollers and plates.

In order to bring the apparatus into operating condition the rollers (namely first the rollers 3 and then the rollers 1) and the plates are initially pressed strongly against each other in order to obtain a high sealing force and to facilitate the build-up of negative pressure in the vacuum chamber, by a vacuum pump (not shown) communicating with the chamber through a conduit 13. Progressive pressure reduction however causes the jacks to be controlled so that they partially relieve the initial forces between rollers and plates, that is to say they compensate the reciprocal pressure resulting from the negative pressure in the vacuum chamber to the amount required to maintain an adequate sealing force (approximately 200 kg/cm of the roller length). Friction problems resulting from excessive contact pressures are thus substantially avoided.

In order to achieve the most uniform possible wear of the seal surfaces between the plates 6 and the individual rollers it is necessary for the said seal surfaces to be of equal size in each roller. Reduction of the sealing force resulting from abrasion can thus be substantially avoided.

To longitudinally feed the textile web at least one pair of rollers, for example the inlet pair 1 as may be seen by reference to FIG. 2, is driven by means of gearwheels 12 which are coupled to a motor. The gearwheels 12 are provided with a so-called corrected tooth system. This is a special tooth system in which the reciprocal power transmission depends on small changes of the centre spacing between both gearwheels. In order to protect the web and more particularly in the treatment of very fine fabrics it is also possible for the pass rollers 4 to be driven. A pair of squeeze rollers 13 may also be provided above the trough to remove excess impregnating liquid from the web.

In operation of such a system a textile web is guided through the nip of the inlet rollers 1 into the vacuum chamber 5 which is partially evacuated through the evacuting conduit 13. The web is subsequently guided through the nip of the rollers 4 into the trough 7, which is filled with impregnating liquid, and in which the fabric of the web is filled with liquid due to the prior evacuation. The excess liquid which adheres to the web is removed by the squeeze rollers after the web leaves the trough and the web may then be subjected to the usual after-treatment.

Reversing rollers for the web may also be provided in the interior of the vacuum chamber so that a substantial length of the said web can be maintained within the vacuum.