US3195163A

US3195163A - Air squeegee

Info

Publication number: US3195163A
Application number: US351649A
Authority: US
Inventors: Townley Eustace Raymond; Harvey Eric Alfred
Original assignee: Ilford Ltd
Current assignee: Ilford Imaging UK Ltd
Priority date: 1964-03-13
Filing date: 1964-03-13
Publication date: 1965-07-20
Anticipated expiration: 1982-07-20

Description

y 1965 E. R. TOWNLEY ETAL 3,

AIR SQUEEGEE Filed March 13, 1964 5 4 FIG] I /5 FIG-.3

United States Patent 3,195,163 AIR SQUEEGEE Eustace Raymond Townley and Eric Alfred Harvey, Ilford, Essex, and Howard Thomas Tillotson, London, England, assignors to lilford Limited, lltord, Essex, England, a British company Filed Mar. 13, 164, Ser. No. 351,649 Claims priority, application Great Britain, Mar. Ztl, 1963, 11,089/63 9 Claims. (Cl. 153ll6) The present invention relates to an apparatus for the removal of surface moisture from a wet travelling web.

According to the invention there is provided an apparatus for removing liquid from the surface of a wet travelling web which comprises a chamber through which the web is constrained to pass, inlet and outlet passages for the web at least one being constituted by the narrow gap between a pair of oppositely curved surfaces, the generating lines of which are parallel to the width of the web, one of said surfaces being fixed and the other being a surface of a floating member which is so mounted as to allow it a small degree of freedom of movement in a sense allowing variation of the thickness of the gap but limited in such movement so that the gap cannot be wholly closed thereby, means for introducing a current of air into said chamber so as to urge said floating member towards its co-operating curved surface and providing a path for such air to impinge on both faces of the web, and means whereby any increase in the thickness of a said gap beyond a predetermined value by reason of movement of the said floating member from a pre-set position causes an increase in the air pressure on said member tending to restore it to its pre-set position.

A particular use for an apparatus of this type is as an air squeegee for the rapid removal of surface water from a web of photographic film during processing. When a length of film is being processed in a normal continuous processing machine it is essential to remove excess surface moisture before the film enters the dryer. Further, when a length of film is being processed in a so-called rapid processor wherein the processing solutions are either sprayed or coated onto the film and then washed off, it may be essential to remove excess moisture after each water wash and before the next processing solution is applied, or before drying. In the past this has been carried out using squeegee rollers, air knives or air squeegees. Squeegee rollers are inclined to scratch the film surface and the air Squeegees and air knives hitherto produced have used too much air.

A film web for processing usually consists of lengths of film joined together or spliced. These splices may be more than twice the thickness of the normal film and so an air squeegee must be designed to enable splices to be passed easily through it and also to ensure that the wider gap caused by the passage of the splice should be quickly closed to its normal size to avoid the escape of too much air through this gap.

A particular embodiment of the invention has as its pair of curved surfaces a pair of cylinders of which one is fixed and the other free to move to a restricted extent. The cylinders can be prevented from wholly closing by providing either the fixed or the floating cylinder with flanges. In a preferred embodiment of the invention the fixed cylinder has flanges.

In order to ensure that after a splice has been passed through the apparatus the floating member returns to its pre-set position, the preferred apparatus is so constructed that when the floating member has been displaced it acts to divert the air supply to cause it to re-set the floating member in its working position.

In one preferred form of the invention, the cylinder ice used as the floating member is arranged to have restricted movement in a parallel sided recess formed in the body of the apparatus. When the cylinder is at the open end or" the recess it abuts the flanges of the fixed cylinder and when it is moved towards the closed end of the recess it acts to restrict the air passage to the central air chamber so causing an increased air pressure on its undersurface which forces it back to the position in which it abuts the flanges of the fixed cylinder. The preferred embodiment of the invention for use as an air squeegee during the processing of photographic film comprises a pair of oppositely curved surfaces at each of the inlet and outlet passages.

In order that the invention may be readily understood the preferred embodiment of the invention will now be described with reference to the accompanying drawings in which- FIG. 1 is an elevation of an air squeegee.

FIG. 2 is a plan view of the squeegee with an end plate removed to show the internal arrangement and to indicate by means of dotted lines the position of channels below the plane surface of the figure.

PEG. 3 shows two cylinders removed from the squeegee to illustrate their shape and shows how the floating cylinder abuts the flanges of the fixed cylinder.

Referring to the figures: FIG. 1 shows an elevation of an air squeegee wherein '7 and 8 are two halves of the squeegee which contain in recesses the

cylinders

1 and 2 and which are held together by the end plates 5. Two pins 4 are held in recesses in the

blocks

7 and 8 and de termine the path of a film by preventing it rubbing against the end plates 5. An air inlet pipe 6 is attached to block 8. The gap between the cylinders l and 2 which is formed by cylinder 2 resting on the flanged ends of cylinder 1 is designated at 3. It is through this gap that the film is threaded and out of which the air is forced.

FIG. 2 which is a plan view of the apparatus with the end plates 5 removed shows how cylinders l are con tained in recesses in block 7 and are locked in place by' rubber sealing strips 9. Cylinders 2 are mounted in recesses it) in block 8 but are free to move in these recesses. They are normally held against the flanged ends of the cylinders l, as shown in the figure, by air pressure. The ends of the pins 4 are contained in recesses in the

blocks

7 and 8. An air inlet pipe 6 is attached to blocks 8. The gap into which the film 14 is threaded is designated at 11.

The dotted lines on the surface show the air channel which is below the surface of the plane of the figure.

These channels enable air to be fed from the air inlet 6' to the cylinder recesses 19. The portion of cylinder block 8 between the cylinder recesses 10 is designated at 12. This is cut away below the surface to enable air from the cylinder recesses ill to be fed into the main air chamber 13.

FIG. 3 shows the

cylinders

1 and 2 removed from their recesses to illustrate their shape and show how cylinder 2 rests on the flanged ends 15 of cylinder 1. The ends of cylinders 2 are rounded off to prevent them jamming against the end plates 5.

When in use air from the inlet 6 enters the cylinder recesses ltl forcing the cylinders 2 to rest on the flanges 15 of cylinders 1. Air also passes from recesses It) into the channel under 12 to the main air chamber 13. As can be seen from FIG. 1 the length of the air chamber 13 is longer than the width of a film threaded into gap 3 by at least the width of the pins 4. This gap either side of a film traveling through the apparatus enables air to be forced to the back of the film. The air is then forced out of the apparatus via the two gaps on either side of the film so preventing the film ever touching either of the two pairs of cylinders.

When a length of film is joined to another length a splice which may be more than twice the normal thickness of the film is formed. When a spliced portion of film enters the apparatus the extra thickness of the film causes at first one of the cylinders Z to go back into its recess and then the other one. passed and film of a normal thickness is passing through the apparatus the air forces back the cylinders 2 onto the flanges of cylinders 1. Excess air pressure to do this is not required because when the cylinders 2 are forced back into the recesses 10 they restrict the air passage into the main air chamber 13 via the channel underportion 12 and therefore all the air is used to force back the cylinders 2 onto cylinders 1. This reopens the passage to chamber 13.

An air squeegee of this type ensures very good squeegeeing characteristics by making use of a very small air gap between the cylinders but still ensuring that the film in the normal way never touches the cylinders. A squeegee of this type is able to pass slices very easily and the cylinders return straight away to their normal position without excessive air pressure having to be used. A squeegee When the splice has of this type may be used in any position or at any angle as the movable cylinder is returned to its original position by aid pressure and not by any reliance on gravity.

It is an advantage of the present invention that excess air pressure is not required to move the cylinders 2. (as noted above). This is of importance because it will be appreciated that when a number of air Squeegees are used on an air supply of limited capacity, increase in air consumption caused by the multiplicity of units would drop the pressure to all theunits, and thus cause relative inefficiency.

We claim as our invention.

1. An apparatus for removing liquid from the surface of a wet travelling web which comprises a chamber through which the web is constained to pass, inlet and outlet passages for the web at least one being constituted by the narrow gap between a pair of oppositely curved surfaces, the generating lines of which are parallel to the width of the web, one of the sa'id'surfaces being fixed and'the other being a surface of a floating member which is somounted as to-allow it a small degree of freedom of movement in a sense allowing variation of the thickness of the gap but limited in such movement so that gap cannot be wholly closed thereby, means for introducing a current of air into said chamber so as to urge said float.- ing member towards its cooperating curved surface and providing a path for such air to impinge on both faces of the web, and means whereby any increase in the thickness of the said gap beyond a predetermined value by reason of movement of the said floating member from a pre-set position causes an increase in the air pressure on said member tending to restore it to its pre-set position.

2. An apparatus according to claim 1 which has as its pair of oppositely curved surfaces a pair of cylinders one of which is fixed and the other of which is floating.

- 3. An apparatus according to claim 1 which has as itspair of oppositely curved surfaces a pair of cylinders one of which is fixed and has flanges at each end and the other, of which is floating.

4. An apparatus according to claim 1 which has as its pair of oppositely curved surfaces a pair of cylinders one of which is fixed and has flangesat each end and one of which is a floating cylinder which is arranged to have restricted movement in a parallel sided recess, one end of which is open and the other end of which is closed, formed in the body of the apparatus so that when the cylinder is at the open end of the recess it abuts the flanges of the fixed cylinder and when it is moved towards the closed end of the recess by a temporary variation in the thickness of the web, it acts to restrict air passage to the air chamber so causing an increased air pressure on its surface which forces it back to the position in which it abuts the flanges of the fixed cylinder.

5. An apparatus according to claim 4- wherein a said pair of cylinders is provided at said outlet passages. V

6. An apparatus for removing liquid from the surface of a wet travelling web which comprises a chamber through which the web is constrained to pass, inlet and outlet passages for the web at least one being constituted by the narrow gap between a pair of oppositely curved surfaces, the generating lines of which are parallel to the width of the web, one of the said curved surfaces being fixed and having its ends raised and the other being a floating cylinder which is arranged to have a restricted movement in a parallel sided recess, one end of which is open and the other end of which is closed and which is formed in the body of the apparatus, and means for the introduction of air into the said chamber at the closed end of the said recess, said air acting to urge the floating cylinder towards the fixed curved surface whereby when the floating cylinder is at the open end of the recess it abuts the raised ends of the fixed curved surface such air is enabled to pass into said chamber and impinge on both surfaces of the web butwhen the floating cylinder is displaced away from the position in which is abuts the raised ends of the fixed curved surfacedue to a variation in thickness of the travelling web the said floating cylinder acts to block off the air to the chamber so causing an increased air pressure on its u'ndersurface which forces it back to the position in which it abuts the raised ends of the fixed curved surface.

7. An apparatus according to claim 6 wherein the fixed curved surface with raised ends is a fixed cylinderwit-h flanges on each end.

8. An apparatus according to claim 6 wherein a pair of oppositely curved surfaces are located at both the said inlet and outlet passages.

9. An apparatus according to claim 8 wherein said pair of oppositely curved surfaces consists of a floating cylinder and a fixed cylinder with flanges at each end.

both the said inlet and l References Cited by the Examiner UNITED STATES PATENTS CHARLES A. WILLMUTH, Primary Examiner, ROBERT w. MICHELL, Examiner.

Claims

1. AN APPARATUS FOR REMOVING LIQUID FROM THE SURFACE OF A WET TRAVELLING WEB WHICH COMPRISES A CHAMBER THROUGH WHICH THE WEB IS CONSTAINED TO PASS, INLET AND OUTLET PASSAGES FOR THE WEB AT LEAST ONE BEING CONSTITUTED BY THE NARROW GAP BETWEEN A PAIR OF OPPOSITELY CURVED SURFACES, THE GENERATING LINES OF WHICH ARE PARALLEL TO THE WIDTH OF THE WEB, ONE OF THE SAID SURFACES BEING FIXED AND THE OTHER BEING A SURFACE OF A FLOATING MEMBER WHICH IS SO MOUNTED AS TO ALLOW IT A SMALL DEGREE OF FREEDOM OF MOVEMENT IN A SENSE ALLOWING VARIATION OF THE THICKNESS OF THE GAP BUT LIMITED IN SUCH MOVEMENT SO THAT GAP CANNOT BE WHOLLY CLOSED THEREBY, MEANS FOR INTRODUCING A CURRENT OF AIR INTO SAID CHAMBER SO AS TO URGE SAID FLOATING MEMBER TOWARDS ITS COOPERATING CURVED SURFACE AND PROVIDING A PATH FOR SUCH AIR TO INPINGE ON BOTH FACES OF THE WEB, AND MEANS WHEREBY ANY INCREASE IN THE THICKNESS OF THE SAID GAP BEYOND A PREDETERMINED VALUE BY REASON OF MOVEMENT OF THE SAID FLOATING MEMBER FROM A PRE-SET POSITION CAUSES AN INCREASE IN THE AIR PRESSURE ON SAID MEMBER TENDING TO RESTORE IT TO ITS PRE-SET POSITION.