Patent Application
20140373303
1. Field of the Invention
The subject invention is generally related to media blasting systems and is specifically directed to a pressurized media delivery system for cleaning padeyes and similar open-topped, closed recesses or tie-downs.
2. Discussion of the Prior Art
Generally, a padeye is a recessed cleat or tie-down on the deck of a ship. Padeyes and other components for securing cargo or equipment to a ship are generally referred to as tie-downs, which generically includes padeyes. This invention is directed to padeyes and tie-downs substantially flush mounted on a surface and having a recess or cavity, sometimes referred to as a can, positioned beneath the surface. The terms padeye and tie-down are used interchangeably throughout this disclosure and refer to any unit which is substantially flush mounted on a surface with a recess beneath the surface. Such units are typically set flush with the surface of the deck or floor so that they do not create an obstruction to the surface when not in use.
There are several types of padeyes currently in use. They are generally used to tie-down or secure cargo or equipment in place on the deck of the ship using lines which are secured at one end to the cargo and at the other end to the padeye. Several types of padeyes are shown and disclosed in the following U.S. Pat. Nos. 4,672,909; 5,004,388; 5,106,248; 5,301,627 and 5,535,694. All of theses padeyes have one thing in common. Each is housed in a can or receptacle which is recessed in the deck. Currently, one of the most common padeye has an inverted dome shaped receptacle mounted in the deck with a flat cover having a cross-opening or clover-leaf opening designed to engage a link of chain for securing the cargo to the ship deck. The center opening of the padeye is enlarged to permit the link to be removed for loosening or tightening the chain. Because of the location of the padeye or other tie-down in the deck of a ship, it is in a highly corrosive environment. This requires frequent cleaning of the padeye or tie-down, in particular of the receptacle which is recessed in the deck. The receptacle is prone to collect seawater, oil and other materials which may collect on the deck.
The prior art cleaning methods included removing the padeye or tie-down for cleaning, or using a water or fluid blasting system for pressure washing. The liquids used were somewhat limited because of the need to protect the deck from corrosive materials. At best these systems are expensive and time consuming, and marginally effective.
Typically, the water blasting system of the prior art would permit the cleaning of approximately two or three padeyes per hour. A typical U.S. Naval cargo ship may have several hundred padeyes on the top deck, meaning is would take one hundred or more hours just to clean the padeyes. Since the padeyes have to be cleaned regularly, this has become an almost full time job. In most fluid cleaning systems, the system was open-looped, permitting the fluid to run over the deck during the cleaning process.
Also, since the open top member is generally welded to the receptacle, it is difficult to clean the entire padeye with just a liquid blast. The pressurized stream needs to flow directly from the nozzle to the surface being cleaned. Once a liquid stream hits a surface it dissipates rapidly and there is little or no rebound benefit. Basically, even if such systems were functional for cleaning that portion of the padeye receptacle they were of marginal effect when cleaning the underside of the cover or the junction between the top and the receptacle around the perimeter.
Inability to provide thorough cleaning of padeyes or other tie-downs of this nature results in premature failure, requiring costly replacement. There is a need for a more efficient and more effective system for in situ cleaning of padeyes and the like.
The subject invention is a closed loop system, wherein the cleaning material may be recycled and reused as the padeye is cleaned. It uses a solid, particulate media cleaning agent which is propelled under pressure air to drive the media into the surface of the padeye for abrasively removing corrosion and dirt. In its preferred form the cleaning system of the subject invention includes a housing with an open bottom which may be placed over the padeye. An input conduit or tube is selectively extendable through the housing and into the padeye receptacle. The lower end of the tube is coupled to a nozzle assembly having one or more nozzles. The tube extends above the housing and is rotatable to direct each nozzle to various points in the receptacle. The nozzles may be angled to direct the propelled media to different locations in the receptacle.
Where desired, the tube and nozzles may be selectively positioned above the padeye for cleaning the surface area surrounding the padeye.
In the preferred embodiment, the invention comprises a base housing having a housing outlet designed to be positioned in communication with the opening in a padeye. A media inlet tube or conduit extends through the housing for introducing a pressurized media flow into the base housing and/or through the housing and the opening in the padeye and into the padeye recess. A media outlet nozzle assembly releases a directed pressurized media flow into the area surrounding the padeye or into the padeye recess, as desired. A media exhaust port is provided for removing the released media flow from the padeye surface, padeye recess and the base housing. The system may be a closed loop with the recaptured, exhausted released media reintroduced into the media inlet conduit, or may be a vacuum sealed open circuit with the recaptured media being stored or disposed of, or a combination thereof.
In the preferred form the padeye cleaning system is mounted on a wheeled carriage or dolly for supporting the base housing, supply conduit and nozzles. This makes the system easy to maneuver with little or no disassembly required as the system is moved from work station to work station.
The use of a solid particulate matter provides several advantages over the prior art. First, it can be applied at a lower pressure than the liquid systems. Pressurized water, for example, must be propelled at a pressure of greater than 1400 psi to be effective. The solid particulate media can be propelled under a pressure of around 70 psi or more with better results.
In addition, the solid particulate media stays intact after impact, providing rebound cleaning as it bounces around in the receptacle. This assures better cleaning of hard to reach places, especially around the upper perimeter at the junction between the top of the can or receptacle and the bottom wall of the padeye top member.
In the preferred embodiment of the invention a plurality of nozzle configurations may be used. A first configuration points slightly downward to assure cleaning of the base of the receptacle. A second configuration is substantially horizontal for general cleaning. A third configuration points slightly upward to clean the perimeter of the top of the receptacle and to clean the underside of the padeye cover.
Where desired, a nozzle configuration placing the conduit above the padeye the nozzle outlet above the padeye cover may be used to clean the exposed, upper surface of the padeye cover, and the surrounding deck surface where desired.
In the preferred embodiment of the invention the housing is wheeled to facilitate movement of the housing from padeye to padeye along the deck of a ship.
Using this system, each padeye generally takes approximately ten to fifteen minutes to fully clean, permitting cleaning of up to six padeyes in an hour, versus two when using prior art systems. In addition, when using either the closed loop system or the captured exhaust system, there is only a minimum of clean-up after each padeye is completed. This is in contrast with liquid systems which almost always release the cleaning liquid to the deck. In addition, water blasting requires rust inhibiting additives so only rust inhibitive compatible paint can be used on the surfaces being cleaned. The water has to dry before re-painting can begin and protective gear is required to worn by the operator. The system of the present invention eliminates these issues.
The closed loop and/or recovery system of the subject invention is also desirable over the open systems of the prior art because it minimizes any environmental hazard. Basically, the padeye cleaning system of the present invention provides a safer, cleaner, faster and less expensive system for cleaning recessed padeyes on a ship deck.
A basic configuration of the padeye cleaning system of the subject invention is shown in
In the preferred embodiment the system is mounted on a wheeled dolly 20 for portability and maneuverability. As shown in
The control box 24 houses the indicator lights for blast air ON, grit flow ON, and vacuum sensed inside base chamber. The control system for the padeye cleaning system operates in typical manner as is well-known in the industry and provides controls for initiating and terminating flow through the inlet tube 26 via the flexible blast hose 28 and the connector 30. Typically the control box 24 includes a three position switch for system OFF, grit blasting (compressed air and grit ON), or compressed air only, AIR, (no grit). The compressed air only mode is used to help purge the tie down and base chamber of residual grit and trash.
Below is the control box on the dolly is the vacuum switch 32 which disables the system until sufficient vacuum is sensed inside the base chamber 34, see
The blast hose 28 terminates at one end at a swivel coupling 36, and at the other end at the coupling 30 which is used to connect the system to a blast pot (not shown) which properly mixes the grit and compressed air and conveys it to the angled blast nozzles in the nozzle assembly 27. The flexible blast hose permits vertical adjustment of the inlet tube 26 and the nozzle assembly 27. The inherent curve 38 of the blast hose at this location is an accelerated wear point. By providing the short modular section of hose 28 the end user will only have to replace a small length of hose instead of the entire supply hose from the blast pot to the input tube coupler 36.
The wheel 40 is provided for rotating the nozzle inlet tube 26 and nozzle assembly 27 during operation.
Between the threaded rod plate 54 and the base flange 58 is a gasket 62 to seal the blasting chamber 34 inside the base 11. Below the base flange 58 and located on the base 11 is an atmospheric vacuum intake port 36 (
A clean out port 68 is provided for purging the system and cleaning out the blast chamber 34 during blast and purge operations. The clean out port is connected to a vacuum system (not shown) for reclamation, screening and reusing the abrasive.
In the preferred embodiment of the invention the inlet tube (blast wand) 26 and nozzle assembly 27 are mounted in the lift tube 50 for rotation and vertical adjustment relative to the base 11. As shown, the fixed threaded rod 52 is mounted on the base plate 58 which is removably secured to the base 11 by the disconnects 60. In the exemplary embodiment a threaded receptacle such as, by way of example, the nut 70, is provided in or on the base plate 54. The threaded rod 52 is then secured in the receptacle 70. This prevents dirt and grit from accumulating in these gaps.
A similarly threaded receptacle or nut 72 is secured to the lower end 74 of the lift tube 50. Handles 76 are mounted in the lift tube 50 to facilitate rotation and vertical adjustment of the lift tube relative to the threaded rod 52 and to the base 11. In the embodiment shown the handles 76 are hollow pipes or tubes open to the interior of the lift tube. These function as a fresh air intake to continuously purge the gap between the internal diameter of the threaded rod 52 and the outer diameter of the blast wand 26, see opening at 78.
As best seen in
As also best shown in
The nozzle positions during operation are illustrated in
Where desired, the wheel 25 may include indexing marks 110, 112 on its perimeter to show the position of the nozzles during rotation. This permits non-visual systematic geometric blast coverage by providing an external indication of each nozzle position during rotation. As shown in
While certain features and embodiments of the invention have been described in detail herein, it should be understood that the invention includes all modifications and enhancements within the scope and spirit of the following claims.
