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US 4,816,296 AGranted
Tangential jet air pipe coating apparatus and method
OwnerJack E. Gibsoninventor
Life of this patent
Estimating the term…
Abstract
The difficulty of applying uniform plastic coatings to the interior of pipe and other tubular goods increases in proportion to the diameter and length of the pipe. Epoxy is one of the most satisfactory plastic coatings for use on oilfield pipe. An epoxy coating preferably is applied on powdered form to the heated, rotating pipe interior, where the plastic is fused into a continuous film and thereafter the pipe is cooled as the film solidifies to provide a superior coating which protects the metal pipe surface from chemically reacting with the material flowing therethrough, thereby elongating the life of the pipe.
Claims13
Method of coating the interior of an elongated tubular member, such as oil field pipe, using a powdered synthetic resin which is fused into a continuous coating, comprising the steps of:
- preheating the pipe to a temperature in excess of the fusion temperature of the powdered synthetic resin material;
- rotating the preheated pipe about its longitudinal axis at a speed to cause any subsequently fused synthetic resin material to spread into a continuous film about the interior of the pipe;
- providing an elongated cylindrical housing with an inlet end and an outlet end;
- removably connecting one end of the preheated pipe to the outlet end of said elongated cylindrical housing;
- flowing air tangentially into the elongated cylindrical housing at a location spaced from the inlet and outlet ends of said elongated cylindrical housing;
- flowing air through an air valve means and axially into the inlet end of the elongated cylindrical housing;
- storing a charge of powdered synthetic resin within a container separate from said cylindrical housing, and flowing the charge through a powder valve means and into the elongated cylindrical housing at a location downstream of the inlet end and upstream of the tangential air inlet;
- said charge contains an excess of powdered synthetic resin required to coat the interior of the pipe;
- forming a pocket of powdered synthetic resin by sequentially operating the air valve means and the powder valve means respective to one another with said air valve means being opened immediately following expelling of the powered synthetic resin and thereby translocating the powdered charge by expelling a charge of powdered synthetic resin from the container into the elongated cylindrical housing, where the powdered synthetic resin admixes with the axial air flow and is forced downstream into the tangential air flow, whereupon the tangential air flow imparts a spiral flow into the pocket before the pocket enters the heated rotating pipe;
- said charge flows through the pipe as a spiraling pocket of powdered synthetic resin admixed with air;
- said pocket has a volume which is smaller than the volume of the pipe;
- said pocket flows only one time through the elongated cylindrical housing and into the pipe;
- whereby, the preheated rotating pipe is internally coated with a continuous coating of the synthetic resin material.
10 more elements
Method of powder coating the interior of a joint of pipe with a powdered synthetic plastic resin material, comprising the steps of:
- (1) preheating the pipe joint to be coated to a temperature in excess of the fusion temperature of the powdered plastic resin;
- (2) rotating the preheated pipe joint about its longitudinal axis at a rotational velocity which causes any subsequently fused plastic resin material applied to the internal surface thereof to spread out into a uniform continuous film;
- (3) removably connecting an inlet end of the rotating preheated pipe joint to an outlet end of a non-rotating cylindrical chamber, while the other end of the pipe joint is connected to a source of pressure which is less than the pressure contained within the cylindrical chamber;
- said cylindrical chamber having an inlet end spaced from said outlet end;
- (4) isolating a charge of powdered plastic material within a container which is separate from the cylindrical chamber;
- said charge being in excess of the quantity of material required to coat the interior of the pipe joint;
- (5) flowing air tangentially into a downstream marginal end of the cylindrical chamber by arranging at least one air nozzle to produce an air flow which moves tangentially respective to the interior of the chamber;
- (6) flowing air through an air valve means and axially into the inlet end of the chamber;
- (7) transferring the charge of plastic powder from said container, through a powder valve means, and into the chamber by sequentially operating the air valve means respective to the powder valve means within a time interval that results in the entire charge assuming the form of a fluidized pocket of plastic resin material which has a length less than the length of the joint of pipe;
- (8) transferring said charge into said chamber at a location upstream of said nozzle and downstream of the axial air inlet end;
- (9) whereby;
- said pocket assumes a spiral flow pattern as the pocket flows through the outlet end of the chamber and through the pipe, and the plastic material contained within the pocket contacts and fuses to the interior wall of the pipe to form a continuous coating.
9 more elements
Method of applying a coating of plastic resin on the interior of a joint of pipe by using a powdered plastic resin material, comprising the steps of:
- (1) selecting a plastic resin material in particulate form which is capable of being fused to the interior wall surface of the joint of pipe;
- (2) preheating the joint of pipe to a temperature in excess of the fusion temperature of the plastic resin material;
- (3) rotating the preheated joint of pipe about its longitudinal axis at a speed which enables any subsequently fused plastic resin material to spread onto the interior wall surface of the joint of pipe as a continuous film;
- (4) providing an elongated cylindrical housing with an inlet and an outlet, isolating a charge of the plastic resin material of step (1) within a container;
- said charge being in excess of the amount of plastic resin material required to uniformly coat the interior wall surface of the joint of pipe;
- (5) flowing air through an air valve means, into said housing inlet, and axially respective to the interior of said housing;
- flowing air through a nozzle arranged tangentially respective to the axial air flow at a location downstream of the housing inlet and upstream of the housing outlet;
- (6) communicating one end of the rotating, preheated, joint of pipe with the outlet of the housing while connecting the other end of the joint of pipe to a source of reduced pressure respective to the interior of the cylindrical housing;
- (7) using a powder valve means to connect said container to said cylindrical housing so that said charge can be rapidly transferred from the container into the cylindrical housing at a location upstream of said tangential air flow from said nozzle;
- (8) forming the charge of plastic resin material into a pocket comprising a mixture of air and plastic resin material by sequentially opening the air valve means and powder valve means and forcing the entire isolated charge of step (4) to flow from said container into the interior of the housing at a rate of flow which results in a pocket volume which is less than the volume of the joint of pipe, whereupon the pocket enters the pipe as it spirals about the longitudinal axis of the joint of pipe and plastic resin particles contact and fuse to the interior sidewall of the joint of pipe to provide the aforesaid coating of plastic resin.
7 more elements
Apparatus for powder coating the entire inside surface of an oil field pipe joint with a heat fusible powdered plastic resin, comprising:
- preheating means for heating the pipe joint to a temperature about the melting temperature of the powdered plastic resin;
- means for rotating the pipe joint about its longitudinal axis;
- means forming an elongated housing having an inlet spaced from an outlet, means forming a powder containing container separate from said housing, means by which said housing outlet can be removably flow connected to the inlet end of the rotating pipe to be coated;
- powder valve means including a powder inlet connecting the container interior to the interior of said housing at a location downstream of said inlet;
- air valve means connected to provide said container and said housing inlet with a source of compressed air;
- means by which a charge of powdered plastic resin can be placed within said container;
- said charge being of sufficient quantity to coat the inside of the pipe joint;
- air nozzle means supported by said housing and directed tangentially respective to the housing interior for producing a spiral flow of air within the marginal outlet end of the housing and through the pipe joint;
- said nozzle means are arranged about the circumference of the housing and have an outlet oriented to flow in a circumferential direction respective to the housing interior, said nozzle means being located downstream of the powder inlet and said powder inlet being located downstream of said housing inlet;
- whereby, when said air valve means and said powder valve means are moved to the open position, the charge of plastic resin is changed into a fluidized pocket of plastic particles which flow in a spiral through the pipe joint as the particles of plastic deposit and fuse to the interior wall of the pipe joint.
7 more elements
Dependencies are inferred from the claim text.