A method for coating a pipe involves applying a coating material of cellular structured extruded thermoplastic material to the pipe and enclosing it on the outside by an outer covering layer of compact plastic. In an extrusion head, the annular opening for supplying coating material can be adjusted to a desired temperature by a region having coolant channels separated from the annular opening by an annular heat exchange surface. Before being applied to the pipe, the flowable coating material is guided along the heat exchange surface and cooled to a temperature just above the solidification temperature thereof. After the coating material leaves the annular opening, the coating material expands in a controlled manner, widening the outer covering layer depending on the adjusted temperature of the coating material, until the coating material begins to solidify. The outer covering layer surface condition can correspond to or be different from the pipe.

A large-aperture spiral welded steel pipe with metal linings and a manufacturing method thereof, wherein the pipe includes a pipe body spirally winded by a main steel belt; a first lining and a second lining are arranged on a body inner wall, the first lining is spirally laminated on the main steel belt surface, the first lining width is smaller than the main steel belt width, the second lining is spirally laminated on a spiral seam formed between adjacent pipe bodies, the second lining left and right sides are respectively welded with the adjacent first lining, and the first lining and the second lining cover the inner wall of the entire body; and a reinforcement ring with a semi-closed section is spirally arranged along a body outer wall, and a spiral passage is formed between the inner wall of the reinforcement ring and the body outer wall.

A large-aperture spiral welded steel pipe with metal linings and a manufacturing method thereof, wherein the pipe includes a pipe body spirally winded by a main steel belt; a first lining and a second lining are arranged on a body inner wall, the first lining is spirally laminated on the main steel belt surface, the first lining width is smaller than the main steel belt width, the second lining is spirally laminated on a spiral seam formed between adjacent pipe bodies, the second lining left and right sides are respectively welded with the adjacent first lining, and the first lining and the second lining cover the inner wall of the entire body; and a reinforcement ring with a semi-closed section is spirally arranged along a body outer wall, and a spiral passage is formed between the inner wall of the reinforcement ring and the body outer wall.

An apparatus comprising a multi-layer duct liner which can be inserted into existing duct systems such as HVAC system ducts. In facilities where micro-organisms are a concern, the linings may be chemically treated. When it is time to clean the ducts, the innermost lining is removed by detaching it from the remaining layers and removing it from the system.

An apparatus comprising a multi-layer duct liner which can be inserted into existing duct systems such as HVAC system ducts. In facilities where micro-organisms are a concern, the linings may be chemically treated. When it is time to clean the ducts, the innermost lining is removed by detaching it from the remaining layers and removing it from the system.

An underground steel-concrete structure pipeline with a spiral composite reinforcement ring on an inner wall and a manufacturing method thereof. The pipeline includes a pipe body, multiple rows of concrete overflow holes spirally arranged on a pipe wall of the pipe body, a reinforcement ring capable of wrapping the concrete overflow holes, and concrete is filled in a hollow cavity between the reinforcement ring and the pipe wall to form a spiral concrete flow passage. The advantages are that the overall annular strength of the pipeline is reinforced by the reinforcement ring; the concrete filled between the reinforcement ring and the inner wall of the pipe body improves the compressive strength of the pipe body; the concrete overflowing from the overflow holes on the pipe wall combines the pipe body with a pit; and the pipeline solves the difficulty of using large-size steel structure products in underground common pipeline projects.

An underground steel-concrete structure pipeline with a spiral composite reinforcement ring on an inner wall and a manufacturing method thereof. The pipeline includes a pipe body, multiple rows of concrete overflow holes spirally arranged on a pipe wall of the pipe body, a reinforcement ring capable of wrapping the concrete overflow holes, and concrete is filled in a hollow cavity between the reinforcement ring and the pipe wall to form a spiral concrete flow passage. The advantages are that the overall annular strength of the pipeline is reinforced by the reinforcement ring; the concrete filled between the reinforcement ring and the inner wall of the pipe body improves the compressive strength of the pipe body; the concrete overflowing from the overflow holes on the pipe wall combines the pipe body with a pit; and the pipeline solves the difficulty of using large-size steel structure products in underground common pipeline projects.

A pipeline has two groups of reinforcing circular ring bodies welded on large flanges at two ends of the pipeline, reinforcing rebar plates and integral reinforcing steel circular pipe fittings are combined and welded symmetrically. Microcrystalline glass lining has level-8 Mohs hardness. By adopting an openable and closeable extra-long horizontal electric heating furnace provided by the present invention and an intelligent temperature control instrument in combination with a new heating-while-rotating process, the extra-large and extra-long integral large micro-crystallized glass-lined pipeline which is high in glass lining layer quality, smooth in circulation, durable, non-corrosive, wear-resistant, high in seismic performance and safe in operation is developed. Various existing pipelines will be inevitably and comprehensively replaced due to comprehensive extra-strong advantages.

The liner includes a rib formation with a transverse section configured to mechanically lock the liner to a concrete shell and a joint to allow the rib formation to flex. The joint for the rib formation can comprise a first side spaced apart from a second side with each joined to the transverse section to allow each side to flex with respect to each other. The space between the first side and the second side can be filled with a weld material to add rigidity to the rib formation while allowing it to flex. Each of the first side and the second side can be combined at the other end to a shell. The combined rib formation and shell are spirally wound to create the liner.

The liner includes a rib formation with a transverse section configured to mechanically lock the liner to a concrete shell and a joint to allow the rib formation to flex. The joint for the rib formation can comprise a first side spaced apart from a second side with each joined to the transverse section to allow each side to flex with respect to each other. The space between the first side and the second side can be filled with a weld material to add rigidity to the rib formation while allowing it to flex. Each of the first side and the second side can be combined at the other end to a shell. The combined rib formation and shell are spirally wound to create the liner.