Cleaning and liquid contact with solids – Processes – Including application of electrical radiant or wave energy...
Reexamination Certificate
2000-06-08
2003-03-04
Stinson, Frankie L. (Department: 1746)
Cleaning and liquid contact with solids
Processes
Including application of electrical radiant or wave energy...
C134S002000, C134S022120, C134S008000, C015S003500, C015S104062
Reexamination Certificate
active
06527869
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a system for cleaning the interior of pipes. In particular, the invention comprises a system for cleaning deposits from the walls of pipelines or other pipe systems.
2. Background
Pipeline systems are utilized throughout the world to transport petroleum products, water, municipal wastes, chemical slurries and other fluids. During the transport of these materials there is often a build-up of materials, including paraffin, calcium and silica, on the inner wall of the pipeline. One of the materials which builds up most frequently in petroleum pipelines is paraffin. As the deposits of paraffin and/or other materials increase, the bore of the pipeline or other piping through which the fluid flows becomes restricted, resulting in a loss of fluid flow. or an increase in energy required to maintain the fluid flow.
Pipeline pigs have been used for many years to remove deposits from the inside of pipes. A pipeline pig comprises a body having an outer circumference closely matching the inner circumference of the pipe. The pig is inserted in the pipe and is forced through the pipe by fluid pressure. As the pig travels through the pipe it scrapes the deposits from the interior wall of the pipe and transports these deposits along the pipeline. The pig needs to be substantially rigid in order to scrape deposits form the wall of the pipe, but the pig also needs to be somewhat compressible in order to pass by restrictions in the internal pipe cross-section or obstructions that may be present in the pipe. Typically the exterior surface of a pipeline pig is formed from a plastic material, such as polyurethane. A disadvantage of these pigs is that the build-up of paraffin or other material inside the pipe may be so rigid that the pig will compress and ride over the build-up, which results in insufficient cleaning. Normally, the fluid pressure for propelling the pig through the pipe is supplied by water or other liquids which are injected into the pipe at high pressure following insertion of the pig into the pipe. It is also known to the prior art to initially inject high pressure water behind the pig and to then discontinue the injection of water and inject only a gas to complete the propulsion of the pig through the pipe.
Fluids have been used in conjunction with pipeline pigs for certain cleaning purposes. U.S. Pat. No. 5,795,402, which issued on Aug. 18, 1998 to Hargett, Sr. et al., discloses a pipeline pig having a plurality of nozzles positioned on the forward end of the pig for allowing fluid under pressure to flow from the nozzles onto the inner wall of the pipeline. When the pig encounters an obstruction which hinders forward movement, pressure is increased sufficiently to move a valving member to the open position which allows fluid under pressure to spray from the nozzles to provide sufficient heating to melt the paraffin or other build-up. In one embodiment of the system disclosed in U.S. Pat. No. 5,795,402, a first chemical compound, preferably hydrochloric acid, is positioned forward of the pig, and a second chemical compound, preferably anhydrous ammonia, is positioned to the rear of the pig. When an obstruction is encountered, fluid in a chamber
36
reaches a certain pressure and a sealing member
74
within a pressure valve
70
moves forward, allowing fluid to flow into the nose cone of the pig and out the nozzles. Upon this happening, the anhydrous ammonia encountering the hydraulic acid will create an exothermic reaction and the resulting heat will melt the built up paraffin. When the paraffin has been sufficiently softened the pig is then able to move forward under pressure applied to the rear of the pig. In another embodiment disclosed in U.S. Pat. No. 5,795,402, the water which is used to push the pig is heated to a very high temperature, above the temperature for melting paraffin. When the pig reaches an obstruction of paraffin, valve member
70
is activated, which allows the super heated water to flow into the nose cone of the pig and out of the nozzles under pressure to begin melting or softening the wax build-up. As the pig moves forward, pressure is reduced and the valve
70
closes, and the pressure of the water simply moves the pig along the pipeline until it encounters another obstruction.
U.S. Pat. No. 4,498,932, which issued on Feb. 12, 1985 to Kruka, discloses a pipeline pig having a restricted fluid bypass channel which serves to bring fluid from the back of the pig to its front. This fluid agitates and suspends discrete solids such as sand or rust, or commingles with paraffinic and asphaltic deposits which have been scraped from the pipe wall by the pig as it moves through the line, to prevent the buildup of a solid bed or plug of sufficient thickness or viscosity in front of the pig so as to cause the pig to partially collapse and ride over it or to become stuck. The passageway through the pig is terminated by nozzles or orifices which are fastened to the pig. The orifices are chosen to give a desired flow rate and pressure drop across the pig. In this disclosure, fluid flow through the nozzle is intended to agitate and suspend discrete solids such as sand or rust, or to commingle with scraped paraffinic and asphaltic deposits which have been scraped from the pipe walls by the pig. There is no suggestion, however, of blasting the paraffinic or asphaltic deposits from the pipeline wall with the force of the fluid stream emanating from the nozzles.
U.S. Pat. No. 5,875,803, which issued on Mar. 2, 1999 to Leitko et al., shows a conduit cleaning pig which includes a sealing means for preventing a significant flow of fluids from the upstream side of the pig to the downstream side of the pig between the conduit and the pig. The pig includes a rotating element connected to the downstream side of the seal means and a plurality of nozzles connected to the rotating element, each nozzle defining a flow path. The flowpath through the nozzles is in communication with a channel from the upstream side of the seal. The flowpaths through the nozzles are aligned in part tangentially to the cylinder around the central axis of the pig and aligned in part toward the inside wall of the conduit. Liquid jets of the fluid transporting the pig down the conduit impinge on the conduit in front of the pig and remove deposits from the wall of the conduit. The fluid passing through the pig then transports the solids through the conduit ahead of the pig.
Another system which utilizes a fluid flow to assist in cleaning the inside of a pipe is disclosed in U.S. Pat. No. 5,444,887, which issued on Aug. 29, 1995 to Rufolo. This patent discloses a cleaning device for removing shellfish obstructions from an interior surface of an underwater intake pipe. The system includes a member having a blade-like front surface and a blade-like rear surface for scraping foreign matter from the inside surface of a conduit. The cleaning device also includes fluid jet nozzles for producing a jet stream used in transferring the foreign matter along the pipe's floor. While the system uses a fluid stream to transfer foreign matter scraped from the pipe wall by the blades, there is no suggestion of using the fluid stream to blast the foreign matter from the pipe walls.
Hydro blasting is another method which has been utilized to clean the inside of pipes. The hydro blasting process for cleaning the interior of a pipe typically employs a line mole attached to the end of a hose, which is inserted into the pipe, such as the system illustrated in a brochure from Euro Aqua Drill, of Webster, Tex. High pressure water is supplied to the line mole through the hose, which will extend to the line mole from a high pressure water pump on the exterior of the pipe. The line mole includes nozzles through which water is ejected at a high velocity as the line mole travels through the pipe. Some of these nozzles face in a diagonally forward direction or perpendicular direction with respect to the axis of the pipe, and the water which is ejecte
Stinson Frankie L.
Thigpen E. Eugene
LandOfFree
Method for cleaning deposits from the interior of pipes does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for cleaning deposits from the interior of pipes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for cleaning deposits from the interior of pipes will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3009660