Abstract: A method for distributing fluid along the interior wall of a pipeline wherein a quantity of fluid is placed at a location in the pipeline and exposed at one side to a force acting in an axial and rotational direction. This force will cause at least a portion of the fluid to enter a helical path adjacent the pipeline which will force the material to be coated on the inner wall of the pipeline. As the fluid is coated on the pipeline wall it is exposed to an axial wiping force which smooths out the fluid coated onto the inner wall of the pipeline by removing the excess material.

Abstract: In the practice of the sputter ion plating of refractory metals or refractory metal compounds on substrates to form smooth dense substantially porous-free coatings a method whereby the substrate bias potential can be reduced, thereby reducing the generation of substrate heat, is provided wherein the source material consists of a refractory metal or a refractory metal compound and one or more further metals. The further metal may be another refractory metal. Typical refractory and further metals are tungsten and tantalum.The source material may suitably be a bundle of wires consisting of wires of the refractory metal or metal compound and wires of the further metal.For predetermined glow discharge conditions of source and substrate potentials and ionizable gas pressure, the source material preferably consists of the refractory metal or metal compound and the further metal in proportions to form a solid solution on the substrate.The ionizable gas should be an inert gas of high atomic number.

Abstract: A one step method of applying a sealant onto the inside surface of a pipe, such as a gas pipe, to repair any defective portions that are likely to cause a leak and should be repaired. The sealant is applied and it is then dried and solidified to seal the leak portions of the pipe. Preferably, an injection means is used for supplying the sealant in a cylindrical shape so that every portion of the inner surface of the pipe will be coated.

Abstract: A method of lining a passageway, such as an undergound sewer is disclosed. A fluent but thixotropic cementitious composition is sprayed onto the surface of the passageway, to form a lining of predetermined thickness and before the material has had time to flow to change its distribution on the surface, a flexible tube is everted onto the applied material, holding it in position until it is sufficiently cured.

Abstract: A method of lining a large pipe and small pipes branching therefrom with a seal composition, in which the pipes are lined as connected together, and the large pipe or the small pipes are lined first. The portion of the seal composition forced into the small pipes when the large pipe is lined with use of a running body is returned into the large pipe again and is subsequently applied, without being discharged from the system, to the lining layer of the large pipe as a top coat with use of a running body having a slightly smaller diameter than the running body. When one of the pipes has a greatly bent portion, a running body is used which comprises two members each shaped symmetrically, congruent with each other and interconnected by a flexible linear member.

Abstract: A process and apparatus for coating the interior of a fiber-reinforced tube formed of cellulose hydrate in which a tube filled with a coating liquid is passed through a special conveying and pumping device which also serves to replenish the coating liquid. Above the level of the coating liquid, the tube is inflated with a support gas and is gradually flattened. The flattened tube then travels through a metering device made up of wipers in the form of doctor blades or rollers, which retain the major quantity of the coating liquid which is present on the inside surface of the tubing so that a thin, uniform film of the coating liquid is formed. The tubing is thereafter dried to remove the volatile constituents of the coating liquid, and is subsequently wound up.

Abstract: Coatings made from soluable cross-linkable elastomers are shown. Particularly, techniques for solution cross-linking perfluorocarbon copolymers to generate resistant coatings for lining and coating applications are disclosed.

Abstract: A method for producing stratification mass for the production of top surfacing layers particularly through dipping, painting, filling or spraying on a carrier (especially for friction/slide layers of bearing laminates having metallic base members) of a matrix foundation substance of fluoride-held polymers which has admixed metal or metal-alloy particles and/or additive material with friction and/or slide-improving characteristics. The applied layer material is subjected to heat to melt the same, and the layer is then cooled and pressed. The synthetic substance of the matrix can contain a primer, such as chromium oxide.

Abstract: A polymeric foam pipeline pig, having its cells filled with a gel, is resistant to compression when subjected to pipeline pressure.

Abstract: An apparatus for use in selectively coating all or a portion of the interior surface of a tubular article, the apparatus including a plurality of axially spaced apart masks adapted to fit within the tubular article, support structure spacing apart the masks, and an electrically conductive coating means between the masks. The coating means may be electrically activated to spray the unmasked portion of the inside surface of the tubular article.The apparatus is useful in making tubular articles which are coated on their interior surfaces at selective locations. An alternative embodiment of the apparatus includes masks which have been chamfered. When this alternative apparatus is used to coat the interior surface of the interconnect, a non-uniform coating is delivered to the ends of the area which are coated. Using this alternative apparatus, a stress graded coating may be applied to the selectively coated interior surface.

Abstract: A method for lining main pipes, to which branching domestic connection pipes are connected, with an internal coating of a hardening plastic composition with which the main pipe is spread, comprising introducing from the interior of a house an inflatable bladder with a connected pressure line into an opened domestic connection pipe into a region of its junction with the main pipe, inflating the bladder through the pressure line and closing the domestic connection pipe tightly in pressure-tight manner by the bladder in the region of the junction with the main pipe, spreading the main pipe with plastic composition to form an internal coating therein. A composition plug, being determined in size by the position of the bladder, thereby is forced into the junction of the domestic connection pipe.

Abstract: The invention relates to a process for providing an adherent coating of polytetrafluoroethylene (PTFE) on the inner walls of a hollow metal body wherein a flexible membrane is used to form a space between the inner walls of the hollow metal body and the inner walls of a flexible membrane, filling the space with PTFE, compressing the PTFE by deformation of the membrane under isostatic pressure, removing the membrane, filling the inner cavities of the hollow metal body with a substantially incompressible solid substance having fluid flow characteristics and being thermally stable at the temperatures to which the PTFE is to be heated, heating the thus-formed assembly to a temperature above the melting point of the polytetrafluoroethylene for a period of time sufficient for the latter to lose its crystallinity.

Abstract: A method of curing a layer of RTV encapsulating material (24) disposed between a substrate (20) and a chip carrier (22), without the formation of voids in the material immediately adjacent opposed surfaces (32 and 34) of the substrate and the chip carrier, respectively, initially involves cleaning the substrate-chip carrier assembly (20-22) with an activating solvent (e.g., xylene), after which the assembly is blow-dried. The encapsulating material (24), having a viscosity on the order of 6-9 poise, then is flowed between the substrate (20) and the chip carrier (22) and a layer of the material also may be flowed over the top of the assembly. The assembly (20-22) next is immersed in a water bath (46), which includes on the order of 10 milliliters of water for each cubic centimeter of the material (24) to be cured, at room temperature under a hydrostatic head on the order of 3-4 inches for on the order of 16 hours or more, while the material cures.

Abstract: A method of impregnating the inner absorbent layer of a long flexible tube with a curable resin is begun by introducing a mass of the resin into one end of the tube. A window is formed in the impermeable outer layer of the tube at a distance from the resin mass. A vacuum in the interior of the tube is drawn through the window and concurrently the resin mass is pushed toward the evacuated region by passing the tube between a pair of squeezing members. When the flowing resin reaches the vicinity of the window, the window is sealed. Another window is formed in the tube farther downstream of the previously formed window. A vacuum is drawn through the new window while the squeezing members force the resin to flow toward the newly evacuated region. The procedure is repeated until the resin has spread through the entire inner absorbent layer of the tube.

Abstract: Disclosed is a process for forming an uninterrupted coating of uniform thickness on the inside of a length of tubing which comprises the steps of forming a loop of tubing with a downwardly inclined portion and an upwardly inclined portion; filling the cavity of the tubing forming the loop with a coating liquid; transporting the tubing along its longitudinal axis in a substantially vertically upward direction to coat the inside of the tubing, above the level of the coating liquid, with an initial layer of coating material; constricting the tubing to lay partially flat along a narrow zone running transverse to the direction of transportation above the level of the coating liquid to retain the greater part of the coating liquid in the constriction zone and form a thin layer of coating liquid of desired thickness on the inside; of the tubing issuing from the constriction zone; filling the cavity of the tubing issuing from the constriction zone with support gas; and exposing the tubing to the action of heat at a s

Abstract: Disclosed is a process for coating the inside of a length of tubing comprising the steps of forming at least one loop of tubing with a downwardly inclined portion and an upwardly inclined portion; filling the cavity of the tubing forming the loop with a coating liquid; transporting the tubing along its longitudinal axis in a substantially vertically upward direction to coat the inside surface of the tubing above the level of the coating liquid with an initial layer of coating liquid; constricting the tubing adjacent to and above the level of the coating liquid with a metering device having a constriction zone which flattens a portion of the tubing passing therethrough to substantially eliminate all of the initial layer thereon and partially flattens the remaining portion of the tubing to allow a desired quantity of coating liquid to remain on the tubing issuing from the constriction zone; filling the cavity of the tubing issuing from the constriction zone with support gas; and, exposing the tubing to the acti

Abstract: A process is disclosed for coating the inside surface of a length of tubing comprising the steps of forming at least one loop of tubing with a downwardly inclined portion and an upwardly inclined portion; filling the cavity of the tubing forming the loop with a coating liquid; transporting the tubing along its longitudinal axis in a substantially vertically upward direction to coat the inside of the tubing above the level of the coating liquid with an initial layer of coating liquid; constricting the tubing adjacent to and above the level of the coating liquid along a constriction zone transverse to the longitudinal axis of the tubing, the constriction zone progressively diminishing in width in the direction of travel of the tubing to reduce the thickness of the initial layer and form a thin layer of desired thickness on the inside of the tubing issuing from the constriction zone; filling the cavity of the tubing issuing from the metering device with support gas; and exposing the tubing to heat at a sufficien

Abstract: A process of enameling the inside surface of hollow vessels, which have two openings at opposite points. In a hot-water reservoir to be enameled these openings are provided at both ends. One opening is connected to a vacuum pump and the other to a conduit which incorporates a valve and leads to an enamel slip reservoir. In a first step, a vacuum pump is operated to pre-evacuate the interior of the hollow vessel so that air is removed from the pores at the inside surface of the hollow vessel. In this step the valve in the slip conduit remains closed. When the vessel has been preevacuated to about 40 to 80 torrs absolute, the valve is opened so that slip flows suddenly into the hollow vessel and fills the pores while the evacuation is continued and slip is sucked into the hollow vessel until the slip emerges from the opening through which the hollow vessel is being evacuated.

Abstract: A method for coating the interior of electrically non-conductive pipes by means of a reactive separation from a gas flowing through the pipe, whereby the gas is dissociated by an electrical gas discharge, and wherein the separation occurs simultaneously throughout the total pipe length. Pulse discharges are used having pulse lengths which are so adjusted to the transit time of the gas through the pipe that the time period between two successive pulses corresponds to the time which is required for filling the pipe with unused gas.

Abstract: A method of evaporating an adherent metal electrode coating onto a surface of the zirconia exhaust gas oxygen sensor body. The zirconia is heated to an elevated temperature and the electrode metal evaporated onto the zirconia surface from an adjacent helix. The helix conforms to the zirconia surface and has electrode metal distributed throughout its length. After deposition at a rate of about 0.5-1.0 micrometers per minute is terminated, the zirconia is maintained at the elevated temperature for a few minutes and then slowly cooled for exposure to ambient conditions. Evaporation is from a conforming, closely spaced helix that also preheats the sensor body.

Abstract: The walls 41 (FIG. 4) of thru holes 11 in a printed wiring board substrate 12 are coated with a liquid 24 by inserting fingers 22 into the thru holes. Each of the fingers has a diameter slightly less than the diameter of the associated thru hole and has a length no greater than the thickness of the substrate 12. After ink 24 has been applied to the top surface of the substrate, the inserted fingers 22 are withdrawn, thereby drawing the ink down into the thru holes and coating the walls 41. In another embodiment, fingers 62 are aligned with selected portions 52 of an edge 55 of the substrate 50 to coat the portions of the edge as the fingers are moved by the edge after the heads of the fingers have been coated with the ink 24.

Abstract: A method for coating a tubular food casing includes subjecting an inflated section of the food casing to a cloud of electrostatically charged dry particles and sintering the coated food casing. The process provides a pin-hole free coating and permits a continuous operation.

Abstract: In a process for impregnating a reel of thread in the form of a spool with a liquid resin composition, the thread is arranged on a perforated rigid mandrel so as to form a uniform reel in which the volume of open space approximately corresponds to the desired volume of resin to be impregnated, each spool is then gripped and completely sealed against resin leakage from its ends and, finally, the composition is injected under pressure into the interior of the perforated mandrel whereby there is a homogeneous loss of pressure from the mandrel to the spool's entire exterior curved surface and the resin diffuses uniformly to fill all voids through the spool.

Abstract: Quantity production of friction nuts prepared for subsequent fusion of thermoplastic resin particles deposited in thread grooves therein, in which the nuts are supported with their axes vertical, a fluid slurry of the particles in a liquid carrier is introduced into the threaded interior of the nuts to fill the threaded opening, including the thread grooves therein, to a predetermined level from the bottom of the nuts. Excess slurry is then drained from the bottom ends of the openings. In order to leave the threads clear of obstruction at the bottom of the nut, the deposited slurry, after partially drying, is removed from the bottom thread convolutions by repeatedly inserting and withdrawing a sponge-like material directly into and out of the lower end of the thread opening, or by strongly agitating a small quantity of water in the lower part of the threaded opening.

Abstract: A method whereby slip is applied for providing an enamel coating to interior surfaces of a tank such as a heat exchanger of a hot water boiler, electric water heater and the like fabricated beforehand as by welding. In this method, a larger amount of slip than that actually required for applying the slip coating to the interior surfaces of the tank is introduced into the tank to be applied thereto with the tank being rotated, and the excess slip which has not been applied to the surfaces is forcedly drained from the tank at a rate higher than the rate at which the slip moves relative to the enameled surfaces and which moving rate is determined by the liquid level of the slip within the tank and the size of a discharge port, so that an enamel coating of a desired thickness can be formed on the interior surfaces of the tank. In order to forcedly drain the excess slip from the tank, pneumatic pressure is supplied to the interior of the tank prior to slip application.

Abstract: Disclosed is a method for obtaining a tenacious insitu coating deposition of calcite on the inner surface of water pipes. The calcite coating method according to the present invention has an advantage that it is able to maintain a completely corrosion-free system during the coating, thus assisting the formation of a protective coating of good bonding properties. The method consists in the incorporation of a reagent selected from the group consisting of alkali metal sulfite and hydrazine, in an amount which is at least the stochimetrically required to deoxygenate the aqueous solution utilized for said coating, which is supersaturated with respect to calcium carbonate having a dissolved calcium and carbonate levels of above 100 ppm. The calcite producing ingredients are supplied to the water stream in quantities supplementing concentrations available in the natural water used, giving the required supersaturation levels by addition of suitable salts.

Abstract: A reference electrode is rapidly automatically applied to the interior of tapered vitrified zirconia thimbles for an exhaust gas oxygen sensor. The coating is consistently smooth and predetermined in physical and electrical characteristics. In a specific example, a hollow elastomeric finger is nested within the thimble after dispensing a measured quantity of conductive ink into the thimble bottom. A gas jet applied to the ink from the finger lower end flows the conductive ink throughout a coating cavity below a shoulder in the finger after the ink quantity is substantially all applied to cavity walls, it no longer blocks a cavity vent, and allows the gas to flow freely through the cavity. Gas flow is then discontinued, and the finger withdrawn from the thimble.

Abstract: The modified chemical vapor deposition process is practiced using an rf source as the external heat source. An rf plasma is thus established within a glass tube through which appropriate glass precursor vapors are passed. As a result of the ensuing chemical reactions, particulate material is formed within the tube and deposits on it. The hot plasma zone may be used to consolidate this particulate material into a transparent glass, and onto the interior wall of the tube. The tube is subsequently drawn into an optical fiber.

Abstract: A method of powder coating the inside of tubular goods, such as oil field pipe and the like, by connecting one end of the pipe to a means for producing a flow of compressible gases therethrough. The other end of the pipe is open to atmospheric pressure. A valve means is connected upstream of the pipe between the inlet end thereof and a container for holding a single charge of plastic powder. The charge of powdered plastic is isolated upstream of the pipe inlet. The charge is of sufficient size to coat the entire inside peripheral wall surface of the pipe with a substantial uniform coating of plastic.

Abstract: A solderless electrical connector comprising a printed circuit board and electrical contact terminals mounted therein. A printed circuit board is fabricated to the construction stage wherein conductive circuitry interconnects plated through holes formed therethrough. The exposed circuitry and plated through holes are covered with a conformal coating of insulative material which seals the outer surfaces of the conductive materials from the environment and its effects. The insulative coating obviates the need for solder to protect the conductive materials as well as precludes the use of solder for electrical interconnection therewith. The plated through holes are constructed for press fit insertion of contact terminals in tight frictional engagement therein. The press fit insertion of a contact having an angular edge portion effectively penetrates the insulative coating by deforming it away from that portion of the plated through hole brought to bear against the contact.

Abstract: A method for controlling the coating with alumina of ceramic monolithic catalyst supports on a production basis to achieve repeatability of coating utilizing a vacuum system to distribute a coating slurry of alumina over the interior surfaces of and purge the excess coating slurry from the support at the same time that plugged tubular passageways through the support are unplugged, comprising the steps of applying the coating slurry to the support which has at least about 100 axially aligned tubular passageways to the square inch and subjecting the support to a vacuum to draw the slurry through the passageways and remove plugging and excess slurry to form a coating of alumina on the passageway surfaces. The support is dried and calcined to fix the alumina coating on the passageway surfaces.

Abstract: A method for controlling the coating of ceramic monolithic catalyst supports on a production basis to achieve repeatability of coating utilizing a vacuum system to distribute the coating slurry over the interior surfaces of and purge the excess coating slurry from the support at the same time that plugged tubular passageways through the support are unplugged, comprising the steps of applying the coating slurry to the support and subjecting the support to a vacuum to draw the slurry through the passageways and remove plugging and excess slurry to form a coating on the passageway surfaces. Apparatus for practicing the method is adapted to either dipping the support in the slurry or charging the slurry to the support at its upper end as positioned in the apparatus.

Abstract: A vacuum metallizing apparatus and method for coating the inside of hollow articles, e.g. tap control knobs, in which the article is engaged with a seating of a hollow body so that the interior of the article and the hollow body define a chamber in which high vacuum can be induced through the hollow body. A heating assembly is mounted in the hollow body for vaporizing the coating metal. The heating assembly is enclosed by a shield and may be associated with a shutter that is movable to interfere with deposition inside the article for certain coating metals.

Abstract: A method and apparatus for impregnating a tube of absorbent material in which a mass of flowable material to be absorbed is inserted into the tube by a supply conduit, a vacuum is applied to the tube in spaced relation to the inserted material by a suitable source of vacuum, a flattening device is provided to compress the tube, and the tube is transported by an elongated conveyor through the flattening device commencing at the absorbent material and progressing toward the vacuum to spread the material from side to side of the tube and to extrude the material along the tube.

Abstract: A method and apparatus are provided for applying liquid to solid surfaces to which access may be limited or restricted. Liquid is continuously fed to an applicator where the liquid clings to a supporting surface to form a bead defining an outwardly exposed meniscus protruding beyond the applicator. The applicator is moved along the surface in a proximate relationship thereto which brings the protruding meniscus into contact with the surface to wipe liquid onto the surface, the applicator all the while being spaced a slight but noncritical distance from the surface. A portion of the liquid wiped onto the surface is immediately aspirated from the surface by suction applied through the applicator to leave on the surface a deposit of liquid controlled in quantity by the degree of aspiration accompanying the wiping of liquid onto the surface.

Abstract: A hybrid integrated circuit package and a method for fabricating the package. The package comprises a ceramic substrate having a blank metallization and feedthroughs screen printed thereon. A ceramic seal ring is joined to the substrate to form the side walls of the package. The substrate metallization is plated with nickel and gold and external leads are brazed to the ends of the feedthroughs. As such the package is suitable for use with a large number of different integrated circuits. The package can be adapted for use with a particular integrated circuit function by selectively patterning the blank substrate metallization. This is accomplished by laminating a preformed piece of dry film photoresist material to the package bottom. This piece of photoresist is then exposed through a photographic mask using a collimated light source.

Abstract: There are disclosed a method and an apparatus for the production of photographic materials by vacuum deposition of silver halides on a continuously moving substrate. The silver halides are heated in a crucible placed within a vacuum chamber by radiant heating means disposed outside the chamber and the crucible is so shaped and positioned so close to the continuously moving substrate that a stream of silver halide vapour impinges perpendicularly on the substrate and silver halide is deposited on the substrate at a rate of 200 to 2000 A/sec. The substrate is usually primed with a layer of a material which enhances deposition of the silver halide thereon. The use of the photographic material thus produced in the production of direct positive and negatively emitting photographic materials is described.

Abstract: An improved electrical grade concrete insulator is prepared by immersing a self-supporting concrete body impregnated with an uncured polymer in a liquid curable resin bath, curing said polymer, separating said body from said resin bath whereby said body has a secondary impregnation filling the voids produced when the primary impregnation shrinks on curing. The residual resin on the outside also forms a thin sealant coating on the surface of said body.

Abstract: The interior of a pipe is coated with a uniform thickness of plastic. A fluidized bed of heat-meltable plastic material in particular form is connected to the inlet end of the pipe, while the opposed end of the pipe is made attachable to a source of reduced pressure. A source of compressible fluid is also connected to the inlet end of the pipe. The pipe is preheated and then rotated axially while the compressible fluid flows therethrough. The compressible fluid flowing to the inlet is suddenly terminated while a flow from the fluidized bed is immediately established so that the vacuum at the outlet end of the pipe causes uninterrupted mass flow and pulls a finite pocket of the finely divided plastic into the pipe. The flow of particular plastic material is terminated, while the flow of compressed gas is immediately re-established, thereby pushing the pocket of plastic material into and through the pipe.

Abstract: A method and an apparatus for lining the interior surface of metal tubing with a protective coating made from either thermoplastic or thermosetting resins. The process is effectuated by the insertion of said resins into the tubing in the form of a knitted or braided mesh, smooth surfaced rods, latticed rods, or rods with perforations; the formation of a vacuum within said tube, and the rotation and heating of the outer surfaces of the tubing.

Abstract: A method for producing a tubular multi-layered porous barrier comprising the step of depositing fine powder onto at least one of the inner and outer surfaces of a sintered tubular porous support member in a layer of uniform thickness to form a fine powder layer and pressurizing said powder layer against said support member to form a porous barrier layer on the support member.

Abstract: Disclosed is a pitch-impregnated fiber pipe having a surface coating of pitch containing aluminum pigment. The method of manufacture comprises suspending unimpregnated, conventionally manufactured porous fiber pipe tubes in a suspension of aluminum powder in the liquid pitch and forcing the pitch into the pores and interstices of the fiber pipe tubes.

Abstract: A burner assembly in which various elements are joined in a manner which ensures gastight integrity of the assembly. A porcelain-coated base plate is formed of a pair of overlying steel sheets with integral embossments defining air-gas ducts to burner heads mounted on the base plate and defining ignition tubes for conducting a flame from a pilot housing to the burner heads. The air-gas ducts are sealed by establishing a pressurized flow of a slurry of ceramic frit therethrough, which is effective to coat the full interior of the ducts and close any crevices formed between the sheets. The burner head elements are arranged to provide metal-to-metal sealing engagement with peripheral edges of apertures in the base plate sheets which are characteristically free of porcelain enamel coating. An annular embossment on one of the sheets is preloaded by deflecting it toward the other sheet during assembly of the burner head elements.

Abstract: A method of and apparatus for sealing porous material defining a recess therein by placing sealing liquid in the recess, inserting a tubular means therein, pressure sealing said means with respect to the recess and forcing said sealing liquid into the pores by a gaseous pressure applied through said tubular means.

Abstract: A method for repairing ruptured or otherwise damaged or weakened large diameter pipes such as underground water or sewer pipes, includes opening the opposite ends of the pipe to provide access, cleaning debris from within the pipe and smoothing its inside surface. A peripherally expandable fibrous web reinforced synthetic organic resinous tube which is either thermoplastic or thermosetting and in an uncured state is inserted in the pipe and clamp to the ends thereof by end plates and expanded into tight engagement with the pipe wall by circulating hot pressurized air through the tube. The interface of the pipe and tube may be provided with a heat sensitive adhesive and where the tube resin is thermosetting, the hot air is maintained until curing or setting is effected. Thereafter the repaired pipe is flange reconnected to the opposite end pipes.

Abstract: A method is provided for the continuous manufacture of self-locking internally threaded fasteners having a locking body or patch comprised of resilient thermoplastic material, applied to the fastener in powder form. A support member having a plurality of cavities for receiving said fasteners, and a nozzle associated with each of said cavities, is moved along a path through a plurality of locations wherein the fastener is deposited at a cavity aligned with a respective nozzle at a first location, material is forced through the nozzle onto the fastener at a second location, the fasteners are removed from the respective support at a third location, and the nozzles are purged of material at a fourth location prior to the initiation of a subsequent sequence of operations by the apparatus.

Abstract: This invention relates to a method for coating inner faces of metal pipes of a small diameter which comprises feeding a stream of a powdery resin at a rate of 2 to 10 m/sec into a metal pipe of a small diameter preheated at a temperature higher by 20.degree. to 70.degree.C. than the melting or softening point of said powdery resin so that the concentration of said powdery resin or a mixture of said powdery resin and a carrier is 5 to 40% by volume.

Abstract: A method for coating the inner surface of a metal pipe having an inner diameter of about 1 to 15 cm, which comprises feeding from one end of said metal pipe dry particles of a coating composition into the interior of the metal pipe preheated at a temperature of from a softening point of said coating composition to below a melting point thereof, sucking air at the same time from the other end of the metal pipe so as to form an air stream carrying the particles and flowing in the interior of the pipe at a flow rate of about 4 to 20 m/sec and to allow the particles to deposit on the inner surface of the pipe, and fusing the deposited particles at a reduced pressure of 10 to about 100 mm Hg to form a continuous film on the inner surface of the pipe.