Plastic pipe is continually produced from a curable resin on a plurality of horizontal mandrels which are repeatedly simultaneously moved between plastic pipe production stations. There is at least one station for applying resin to a mandrel, at least one station for curing resin on the surface of a mandrel, and at least one pipe removal station for removing pipe from a mandrel. The pipe stations are substantially radially equidistant from a central horizontal axis and are circumferentially spaced apart by substantially equal increments around the horizontal axis. Each mandrel is progressively rotated between the stations. The temperature of each mandrel is controlled by passing a fluid through the mandrel. Heating fluid passes through mandrels in resin cure stations and cooling fluid passes through mandrels in resin application and pipe removal stations. A control system minimizes mixing of the cooling and heating temperature control fluids when the mandrel is rotated between stations. A distributor system distributes temperature control fluids from fluid reservoirs to the mandrels. Mandrels having a flow path for the temperature control fluid include a cylindrical shell closed at one end and open at the opposed end with a fluid inlet and outlet at the open end. The flow path through the mandrel comprises an open outlet duct within the shell for transferring fluid out of the mandrel through the fluid outlet and an inlet passage between the duct and the inner surface of the shell for transferring fluid into the mandrel from the fluid inlet.
A method of making O-rings by depositing a filament of a liquid hot-melt material onto a rotating spindle, or directly upon the shank of a rotating fastener.
A process is disclosed for forming a thermoplastic structure on the exterior surface of the heated mold form. A mold is heated to approximately two times the melting temperature of a thermoplastic material and particulate thermoplastic material then sprinkled onto the exterior surface of the heated mold. An adhesively bondable material may then be added to the semi-molten thermoplastic material structure. The mold is then cooled and the resulting thermoplastic structure removed. An apparatus for practicing the above process comprising a mold form, heating system, and particulate thermoplastic material dispensing system is also disclosed.
A refrigeration compressor includes a polyamide annular thrust bearing pressfit within a countersunk recess in the rotor aperture and having radially extending lubricating oil grooves on a lower surface thereof. A vertical crankshaft being concentrically disposed within and secured to the rotor at one end and being journalled for rotation within a vertical bore defined by a bearing hub formed in a frame. The bearing hub supports the rotor and crankshaft combination. The bearing hub includes an upper end face which is machine ground and polished to a smooth surface and which is in contact with the smooth lower surface of the thrust bearing thereby forming a frictional pair. A reduction in mechanical friction and power consumption is realized by use of the polyamide thrust bearing and the smooth polishing of the hub upper end face thereby increasing the overall efficiency associated with the refrigeration compressor.
A refrigeration compressor includes a polyamide annular thrust bearing pressfit within a countersunk recess in the rotor aperture and having radially extending lubricating oil grooves on a lower surface thereof. A vertical crankshaft being concentrically disposed within and secured to the rotor at one end and being journalled for rotation within a vertical bore defined by a bearing hub formed in a frame. The bearing hub supports the rotor and crankshaft combination. The bearing hub includes an upper end face which is machine ground and polished to a smooth surface and which is in contact with the smooth lower surface of the thrust bearing thereby forming a frictional pair. A reduction in mechanical friction and power consumption is realized by use of the polyamide thrust bearing and the smooth polishing of the hub upper end face thereby increasing the overall efficiency associated with the refrigeration compressor.
An apparatus for flanging tubular articles of a thermoplastic polymer which has been drawn and heat-set to an elevated temperature comprises a heating die (20) shaped to receive an end of one of the tubular articles (10) and to restrain it from shrinkage, transfer means such as a star wheel (24) to transfer the article (10) from the heating die (20) to a forming die (22) shaped to form an outward flange (12) on said end. Heater coils (33,40) are provided to maintain the dies at the required temperatures; namely the heating die (20) at a softening temperature above the glass transition temperature of the polymer but below the elevated temperature to which it has been heat-set and the forming die (22) at a forming temperature below the softening temperature. Means, such as a pneumatic system (48,50,52) are provided to apply an end of one of the tubular articles (10) to the heating die (20) so that this end is softened whilst restrained from residual shrinkage by the heating die (20) and also for forcing the forming die (22) and the heat-softened end of the tubular article (10) together to form the outward flange (12). Once the flange (12) has been formed, it is cooled e.g. by cooling air whilst restrained against deformation by the forming die (22) to set the flange in accordance with well-defined dimensions.
