US3766879A

US3766879A - Apparatus for coating under water

Info

Publication number: US3766879A
Application number: US00247704A
Authority: US
Inventors: D Jones
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-05-05
Filing date: 1972-04-26
Publication date: 1973-10-23
Anticipated expiration: 1990-10-23
Also published as: DE1924450A1; AU434363B2; FR2044049A5; AU5466069A

Abstract

A method of applying a protective coating to a surface under water which comprises forcing a protective coating composition through an applicator pad, for example using compreseed air, at a pressure at least equal to the ambient pressure of the water at the depth at which the coating is applied, and applying the coating composition to the surface by a smearing action of the pad. Apparatus for carrying out the method includes a porous applicator pad, a reservoir for a protective coating composition to be supplied to the applicator pad, a sensing device for sensing the ambient water pressure, and a control device operative to maintain the pressure at which the composition is supplied to the applicator pad at least equal to the sensed pressure. The applicator pad may be a layer of foamed plastics material having an open interconnected cellular structure.

Description

United States Patent [1 1 Jones Oct. 23, 1973 1 APPARATUS FOR COATING UNDER WATER [76] lnventor: David Fitzherbert Jones, Plummet Water, Narley Woods, Lymington, England [22] Filed: Apr. 26, 1972 [21] App]. No.: 247,704

Related US. Application Data I [62] Division of S er. No. 821,776, May 5, 1969,

abandoned.

[52] US. Cl 114/222, 15/l.7, 118/7, 118/266, 401/204 [51] Int. Cl B631) 59/00 [58] Field of Search 118/7, 9, 10, 266,

[56] v References Cited UNITED STATES PATENTS 2,007,603 7/1935 Green 118/307 X 3,143,756 8/1964 Sisko.... .l. 401/188 3,159,499 12/1964 Jorda 117/2 3,340,561 9/1967 Schwartzman.. 401/206 X 3,396,423 8/1968 Hope .f. 114/222 X Roberts 277/59 X Willcox 114/222 Primary Examiner- Morris Kaplan Attorney-Davis, Hoxie, Faithfull & Hapgood 57 ABSTRACT A method of applying a protective coating to a surface under water which comprises forcing a protective coating composition through an applicator pad, for example using compreseed air, at a pressure at least equal to the ambient pressure of the water at the depth at which the coating is applied, and applying the coating composition to the surface by a smearing action of the pad. Apparatus for carrying out the method includes a porous applicator pad, a reservoir for a protective coating composition to be supplied to the applicator pad, a sensing device for sensing the ambient water pressure, and a control device operative to maintain the pressure at which the composition is supplied to the applicator pad at least equal to the sensed pressure. The applicator pad may be a layer of foamed "plastics material having an open interconnected cellular structure.

9 Claims, 3 Drawing Figures maintenance of marine vessels. In the case of yachts and smaller vessels, it is necessary to haul the vessel out of the water in order to apply paint to the surface of the vessel which is normally under water. In the case of larger vessels, the ship must be placed in a dry dock in order to carry out painting of the lower parts of the hull. In both cases, substantial time and expense are involved in putting the vessel into a condition where the paint can be applied using normal methods. In the case of merchant vessels, the time involved in waiting for a dry dock to be vacant and putting the vessel into the dock is frequently a substantial proportion of the time actually involved in preparing and painting the hull. This, of course, represents a substantial amount of lost revenue while the vessel is out of commission. Nowadays, with larger and larger merchant vessels being built, there are fewer dry docks available for the very large vessels and maintenance of the lower parts of the hulls under water becomes an increasingly intractable problem. i r

Paints are, however, available which are capable of setting to form an adherent coatinglunder water butdifficulty has been experienced in devising a satisfactory method of applying such paints to surfaces under water.

According, there isprovided a method of applying paint to a surface under water which comprises forcing paint to an applicator pad at a pressure'at least equal to the ambient pressure of the water at the depth at which thepaint is applied, and applying the paint tothe FIG. 3 is a sectional side view of the applicator shown in FIG. 2.

Theapparatus shown in FIG. 1 comprises an applicator 1 connected by a conduit 2 to a paint reservoir 3. The paint reservoir 3 may be located on a quay or diving tender, but where the apparatus is portable, it is conveniently carried on the back of a diver. Paint is forced from the reservoir 3 to the applicator by means of compressed air which is fed along a conduit 4 from a control unit 5. The control unit 5 is connected to a source of compressed air (not shown) by means of a conduit 6 having a suitable self-sealing adaptor 7. The pressure in the compressed air conduit 4 is monitored by means of a gauge 8 which is connected to conduit 4 by means of an air line 9. The gauge 8 is conveniently worn on the divers wrist. It will be appreciated that each of the

conduits

2, 4, 6 and 9 are constructed from a flexible material such as rubber or a thermoplastics material. The air supply system also includes a pressbutton operated bleed valve 10 which can be operated .by the diver in order to releasepressure from the system and thus to stop the flow'of paint to the applicator.

. Pressure in the system can be increased by operating a control valve 11 in the control unit 5. The effect of this is to increase the air pressure fed to the reservoir 3 and thus to increase the flow of paint to the applicator 1.

FIGS. 2 and 3 show the construction of the applicator l in more detail. As will be seen, the applicator cornprises a housing member or body 20 formed from a corrosion resistant metal which is provided with a main longitudinal passage 21 for feeding paint to its lower surface. A transverse passage 22 extends from a side wall of the body 20 and communicates with the end of the passage 21 remote from the lower surface of the body 20., The passage 22 is appropriately sized to receive the constrictedend of a stainless steel tube 23 which is formed with an aperture 23a which coincides with the upper end of the passage 21. The tube 23 is clamped into the body-20 by means of two bolts 24 and sealed intothe body by means of an epoxy resin glue.

. Thetube 23 is conveniently provided with a handle 25 surface by a smearing action of the padi'Normally; the

paint is; forced to the applicator by means of compressed-air; l I n The invention provides apparatus for carrying out the method which includesa porous applicatorpad, a reservoir-for paint to be supplied to the applicator pad, a

sensing device for sensing the ambient water pressure,

and a control device operative to maintain the pressure at which the paintissupplied to the applicator pad at least equal to the sensed pressure.

I Preferably, theporous pad is of flexible foamed plas-,

tics material having an open interconnected cellular structure. Examples of suitable foam jplastics materials are polyether, polyester and polyurethane foams having open interconnected cellular structures. It has been (see FIG. 1) and atits free end with a pipeunion26 for connection to the rest of'the ap'paratus'As shown in FIG. 3, the lower face of the ll$ody20 is convexly curved and a layer 27'of flexible foamed plastics material having an open interconnected cellular structure is held in contact with the lower face of the body 20. Desirably, this foam layer is about 5 cms. thick and its flexibilityenables it to conform torthe shapeof the surface being painted and to exclude water from the interface. A ring 28 of brassor other corrosion resistant metal serves to clamp'the pad comprising the foamed plastics layer 27,an'd a towelling outer cover 29 into found advantageous in practice to cover the free face of the plastics foam with a porous fabric and a particularly useful fabric has beenfoundto be a pile fabric contact with theib'ody Snap fasteners 30 (shown hold the ring 28 to the body 20.

only in FIGS. 1 and 2) aregconveniently provided to It vwill be appreciated that the body 20 of the applicator, the tube 23 and the ring 28 may alternatively be manufactured from aplastics material, for example nylon, and in this case the tube 23 may be moulded inte grally with the body during manufacture.

In the use of the apparatus, air is fed along conduits 6 to the control unit 5 which includes means for sensing the ambient pressure at which the apparatus is used and is arranged to supply air along the conduit 4 at a pressure which is at least equal to the ambient pressure.

This ensures that water is not forced backwardly through the applicator pad into the apparatus. When the diver wishes to vary the rate at which paint is fed to the applicator pad, he operates the valve 11 to increase or decrease the rate of supply of compressed air and applies the paint by moving the applicator 1 across the surface to be painted using a smearing action. If the diver wishes to stop the flow of paint to the applicator this can be done by turning the control valve 11 back and pressing the operating button of the bleed valve 10. The control unit 5, however, ensures that the pressure does not drop below the prevailing ambient pressure, 7

because although the air supply is cut off, the pressure within the paint reservoir cannot fall below the external pressure at the pad, unless of course the apparatus is taken to a greater depth.

It is found that using the apparatus in accordance with the invention, it is possible to apply an anti-fouling paint to a thickness of 0.05 mm. in one pass of the applicator. Since there are no cocks, valves or other moving parts in contact with the paint the possibility of clogging is eliminated and cleaning and maintenance are facilitated. When a particular painting operation has been completed and the apparatus returned to the surface, the paint line can be cleaned by simply replac ing the reservoir 3 with a receptacle filled with a suitable paint solvent. By blowing the solvent through the conduit 2 and the applicator 1, the apparatus is effectively and conveniently cleaned.

The applicator 1 can be manipulated by hand, and the one illustrated is designed for such use. However, the applicator may also be manipulated by mechanical means. For example, an applicator may be mounted on an underwater vehicle and be driven so that it performs an orbital movement in contact with the surface to be painted. In a further development of the apparatus, the applicator may be arranged to travel on a magnetic track along the ships bottom or other steel surface and the operator cansimply follow the applicator and control its direction and the flow of paint to the applicator 4 pad.

What is claimed is:

1. Apparatus for applying paint to a surface under water comprising a porous applicator pad, a reservoir for paint, means for supplying paint under pressure from said reservoir to said pad, sensing means for sensing the ambient water pressure adjacent said pad and control means responsive to said pressure sensing means for regulating the pressure at which paint is supplied from said reservoir to said pad.

2. Apparatus according to claim 1, in which the applicator pad is a layer of foamed plastics material having an open interconnected cellular structure.

3. Apparatus according to claim 2, in which the free face of the layer of foamed plastics material is covered with a porous fabric. i

4. Apparatus according to claim 3, in which the fabric is towelling.-

5. Apparatus according to claim 1, in which the pad is held between a retaining ring and a housing member, said housing member having a passage or passages for supplying the paint to the pad.

6. Apparatus according to claim 5, in which the housing member is connected to the reservoir, and the reservoir is connected by a supply line to a source of compressed air for forcing paint from the reservoir ot the applicator.

7. Apparatus according to claim 6, in which a pressure regulator is disposed in the supply line whereby the pressure in the apparatus and hence the rate of feed of the paint can be controlled.

8. Apparatus according to claim 6, in which the supply line includes a normally-closed bleed valve which is adapted on operation to release compressed air from the supply line and thus to reduce the pressure in the supply line.

9. Apparatus according to claim 8, in which a pressure gauge is connected into the supply line.

Claims

3. Apparatus according to claim 2, in which the free face of the layer of foamed plastics material is covered with a porous fabric.

4. Apparatus according to claim 3, in which the fabric is towelling.

6. Apparatus according to claim 5, in which the housing member is connected to the reservoir, and the reservoir is connected by a supply line to a source of compressed air for forcing paint from the reservoir to the applicator.