US 3281885 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
Nov. 1, 1966 s. L. HERSH VACUUM OPERATED SQUEEGEE 2 Sheets-Sheet 1 Filed Sept. 28, 1964 M ASPIRATOR v I'- lili INVENTOR, sev/woun L. HERSH.
ATTORNEN Nov. 1, 1966 s. L. HERSH VACUUM OPERATED SQUEEGEE 2 Sheets-Sheet 2 Filed Sept. 28, 1964 FIG. 5
INVENTOR. SEYMOUR L. HERSH.
A T TORNE 3 United States Patent 3,281,885 VACUUM OPERATED SQUEEGEE Seymour L. Hersh, Freehold, NJL, assignor to the United States of America as represented by the Secretary of the Army Filed Sept. 28, 1964, Ser. No. 399,949 2 Claims. (Cl. -393) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment of any royalty thereon.
This invention relates to a squeegee type drying device for removing surface adherent liquids from such materials as photographic film or other materials from which surface liquid must be removed.
The invention is particularly directed to a spongelike highly absorbent means which is moved along the surface with light pressure to absorb the surface liquid therefrom by capillary action and to continuously and rapidly remove liquid accumulated in the sponge element thereby to maintain the sponge in a highly absorbent condition.
The invention may be used to remove liquids from a variety of sheet materials and is particularly useful upon material having wetted surfaces which are soft and sub- 'ect to abrasion such as photographic film or paper. It has been common practice to use a soft sponge or some sponge like material which is passed over the material to absorb the surface liquid. In this technique the liquid quickly loads the sponge to the point where it fails to function. To restore the sponge the liquid must be repeatedly squeezed to expel the liquid. This is wasted time and moreover the sponge functions at its optimum capacity for only a portion of it operating period.
In addition to the sponge various other manual Wiping devices have been used such as the simple rubber Wiper blade which is not an effective device and fails to protect sensitive surfaces from scratches and abrasions.
In the faster types of squeegee devices the air knife is used. This device applies a flat jet of high pressure air to the surface. This technique, although effective, requires complex and costly equipment for best operation.
Another technique is to use a vacuum cleaner type nozzle which is passed over the wetted surface. A large vacuum pump is required for this system and a tight seal must be maintained between the nozzle and the surface treated. This is difficult to accomplish and subjects the surface to damage by the sealing means.
The present invention overcomes the drawbacks of prior techniques and provides rapid and complete removal of liquid from the treated surface without damage thereto.
The invention is described briefly as follows. The main absorbing component consists of a body of soft resilient sponge which may be the natural variety or a synthetic type and having a working face for engaging the wetted surface. The sponge is enclosed within a casing of suitable material such as plastic or metal. The
casing encloses all but a small portion of the sponge adjacent its working face and is made to fit snugly but not tightly in the casing. The upper portion of the casing is provided with an opening within which is tightly received a tubular fitting to which is attached a flexible tube communicating with a vacuum pumping system. Substan tially the whole volume of the sponge is thus subjected to the vacuum. Thus when the squeegee is lightly moved over the wet surface the capillary action of the pores in the sponge removes the liquid from the surface. However when the liquid enters the sponge it is also acted upon by the vacuum which moves the liquid towards the vacuum connection from where it passes to a draining outlet. In this manner the sponge is continuously main- 3,231,885 Patented Nov. 1, 1%66 tained in optimum working condition and thus is able to remove the liquid rapidly without stopping to expel liquid from the sponge.
An important feature of the invention is the effective manner in which the applied vacuum is confined to the portion of the sponge in contact with the workpiece. By so confining the vacuum the optimum effectiveness of the device :is achieved and maintained.
It is a primary object of the invention to provide a squeegee whose operation is fast, effective and safe.
A further object of the invention is to provide a squeegee which uses the capillary action of a soft sponge and maintains its optimum operation by constant automatic removal of the liquid absorbed by the sponge.
A further object of the invention is to provide a squeegee which is simple in design, may be manufactured at low cost and which requires only a minimum of operating equipment.
A further object of the invention is to provide a squeegee which is rugged and whose effectiveness is not reduced by minor damage to its working surface which engages the area to be dried.
A further object of the invention is to provide a squeegee of the vacuum .type which requires only a low degree of vacuum such as that provided by a conventional aspirator.
A further object of the invention is to provide a squeegee which may be made relatively large in area and will function to provide removal of surface liquid with uniform effectiveness throughout large surface areas.
A further object of the invention is to provide a squeegee which may be adapted for manual use or for application to and to function together with other equipment such as at liquid seals in tanks where the liquid tends to seep from the tank as from resilient lip sealing means in tank walls at points of entry and egress of film strips.
Other objects and features of the invention will more fully appear from the following description and will be particularly pointed out in the claims.
To provide a better understanding of the invention specific embodiments thereof will be described and illustrated in the accompanying drawings wherein:
FIG. 1 is a general view of an embodiment of the device in perspective.
FIG. 2 is a cross section on line 2-2 FIG. 1.
FIG. 3 is a cross section of a different embodiment of the invention.
FIG. 4 is a partial cross section showing a fixed installation of the invention wherein the both sides of a strip type workpiece are acted upon simultaneously.
FIG. 5 is a detail cross section on line 5-5 FIG. 4.
FIG. 6 is a cross section on line 6-6 FIG. 4.
A basic form of the device is shown in FIGS. 1 and 2 wherein a rectangular sponge 10 is received in a solid walled casing 11 which covers the sponge except for the bottom working face 12 thereof and a small portion 13 of the sides thereof. The clearance 13 is provided to prevent contact of the casing with the workpiece 14 which may for example be a photographic film bearing a saturated gelatine emulsion which is very prone to damage.
The sponge should be soft in texture and have good absorption characteristics. It may be of the natural variety or a synthetic type but should have good active capillary action. The principals of the structure and function of the invention depend upon and are supported by the large number of capillary tubes in the body of the sponge which serve as channels for conveying vacuum throughout the sponge in a manner to be described and also to convey liquid from the contacting surface 12 to a waste collecting means or to recirculate the liquid back to a supply tank.
The sponge should be received snugly in the casing but not tightly against the walls thereof. A tubular fitting is secured in an aperture in the top wall of the casing. The fitting is connected to an aspirator 16 or other vacuum producing means. The vacuum thus applied to the sponge permeates throughout the capillary system thereof and adds its motivating force to the natural capillary forces acting within the sponge. Thus only a relatively small capacity vacuum generator is required.
For manual operation the squeegee may be supplied with a handle 17 shown in dotted lines. The device is moved over the surface of the workpiece 14 and while so doing a slight pressure is applied. The resiliency of the sponge acts to insure perfect contact of the entire area of its working face 12 upon the workpiece. Thus as the device is moved over the surface to be dried all liquid is removed leaving no skips or partial removal areas and moreover the operation may be continuous and the squeegee effect remains at optimum effectiveness at all times.
FIG. 3 illustrates a modified construction which substantially increases the operating capacity of the squeegee.\ In this form of the invention the sponge may be of the same construction and is received in a casing having an opening in its top wall to receive a vacuum connection of special construction. Extending upward from the aperture in the casing is a short tubular section or conduit 18 having a plate 19 secured in its upper end and having a plurality of small apertures formed therein. Certain of these apertures 20 have secured therein small capillary tubes 21 which extend down into the sponge to a substantial depth. The lower ends of these tubes may be perforated with small holes 210. Any suitable number of these tubes may be used. As shown in FIG. 6 there are 5 of them the outer tubes being bent outwardly to reach the outer portions of the sponge. The plate 19 also has a plurality of holes 22 shown in FIG. 5 which communicate between the chamber in the tubular portion 18 and a chamber 23 leading to a hose connection 24 which is coupled to a tube or hose 25 leading to a vacuum generator.
The chamber 23 communicates with a small tank 26 the upper rim 27 of which is substantially in line with the plate 19. The tank 26 is supplied with a drain valve 28 through which accumulated liquid may be drained from the tank.
In operation as the squeegee is moved over the workpiece the suction plus the capillary action of the sponge draws the liquid into the chamber in the portion 18 of the casing and also draws liquid through the small tubes 21 wherein the movement of liquid is accelerated by the smooth capillary action of the tubes themselves. Thus the liquid is carried to the top of the plate 19 and flows by gravity into the tank 26 from where it may be disposed of in any suitable manner. It will be seen in this form of the device the full volume of the chamber 23 is maintained free of liquid and thus the full force of the vacuum action is always at its optimum and there is substantially no reverse flow of liquid to the sponge.
The invention in any of its embodiments may be provided with means for securing it to a fixed support in which case the workpiece would be moved over the sponge surface. A fixed system for operating on both sides of a workpiece is shown in FIG. 4, wherein a squeegee device as shown in FIG. 3 acts upon the top surface of the workpiece 14. This device is secured to a fixed support 30. The bottom face of the workpiece is acted upon by a device similar to that shown in FIG. 3 but without the tank 26. The lower squeegee is operated in inverted position and is secured toa support 31. The liquid removed from the lower surface of the strip 14 will flow by gravity through the vacuum fitting 32 and move freely through the tube 33 leading to a vacuum device such as an aspirator. In this arrangement the workpiece is drawn between the two squeegee units 4 which act simultaneously to strip the liquid from both faces of the workpiece 14.
It will be noted that the invention may readily be incorporated into completely integrated automatic systems such as in continuous processing of photographic film wherein the squeegee would be applied to the film after its final washing and may be a fixed station such as that shown in FIG. 4. It should be noted that the invention is well adapted for application to such a system using a plurality of steps in sequence such as in processing exposed photographic materials in which case a squeegee would be applied to each station including stripping wash water therefrom after final washing. By so doing the various solutions stripped from the workpiece surface could be returned to the respective processing tank without contaminating subsequent solutions. In this manner solutions are conserved and due to the effectiveness of the device the quality of the final product is enhanced it being free of water spots, scratches and abrasions.
When using the squeegee in positions other than on the top surface of a horizontal workpiece it is best to choose the form of the invention which affords the best drainage of liquid from the squeegee. A suggested form would be one similar to the lower squeegee in FIG. 4 or the form shown in FIGS. 1 and 2.
The sponge may also be used upon curved surfaces such as when the film strip or other material passes over a guide roll. In this case the operating surface of the sponge should for best performance be shaped to conform with the roll surface. A cylindrical shaped sponge may also be used in which case means should be provided for rotation of the sponge within a casing having a vacuum connection and designed to enclose most of the sponge but exposing a working area thereof suflicient for best operation.
An important aspect of the invention resides in its facility for close control and elimination of vacuum leakage in the device. This vacuum control constitutes a major reason for the high efficiency and efiiectiveness of the device.
To increase the vacuum control the sponge element may be specially constructed to prevent vacuum leakage at the outer surfaces 13 adjacent the operating surface 12. To achieve this end those areas 13 and a small adjacent portion of the sponge surface extending beneath the casing are coated with an impervious and flexible layer such as a thin film 29 of rubber or other material which will bond itself to the sponge and seal off the capillaries therein but will allow complete flexibility of the sponge. This layer should be soft and quite thin. Thus the effective vacuum acting within the sponge is sealed off down to the operating surface thereof despite manipulation of the sponge and moreover the surface of the workpiece is protected from scratches and abrasions.
What is claimed is:
1. Apparatus for stripping liquid from a wetted surface comprising an absorbing member of soft sponge-like material having a capillary cell structure and presenting a working surface; a closely fitting gas tight casing enclosing all but a small portion of said absorbent member extending adjacent said working surface, a hollow liquid controlling enclosure secured to said casing having a relatively large diameter vertical conduit extending from inside said casing to a position within said enclosure located upon substantially a median plane between the top and bottom of said enclosure said conduit having a closure plate at the end within the enclosure, a plurality of capillary tubes in said conduit with their upper ends secured in said plate and terminating adjacent the upper end of said vertical conduit so as to communicate with the hollow enclosure and their lower ends extending a substantial distance into the body of said absorbing member, a liquid reservoir in said enclosure positioned below said median plane and arranged to receive free fiow of References Cited by the Examiner UNITED STATES PATENTS 3/1926 Satterwhite et a1. 5/1964 Compton 15-323 X 6/1964 TOlin 15-419 X 6/1965 Koppehele 15394 X 7/1965 Wisner 15-322 X FOREIGN PATENTS 6/1950 France.
ROBERT W. MICHELL, Primary Examiner.