Abstract: A flat blow molding machine adapted to extrude flat hollow parison from clearance between a flat core and a flat die surrounding the core, characterized in that both ends of the die are slidable in a width direction with respect to a center, the core is replaceable in accordance with expansion and contraction of the die in the width direction. According to this construction, it is possible to change the width of the flat hollow parison extruded from the clearance between the core and the die by sliding the both ends of the die in the width direction and replacing the core upon expansion and contraction of the core in the width direction. Further, if the flat core is constructed from a planar replaceable portion and curved (three dimensional) non-replaceable portions and only the planar replaceable portion is exchanged upon replacement, preparing a plurality of inexpensive-to-manufacture planar replaceable portions having different lengths is enough and the cost is reduced.

Abstract: A method of fabricating a bundle-like pipe unit using a blow molding machine having a plurality of heads feeding parisons into a molding die comprises the steps of forming a plurality of hollows independent from each other in the molding die, forming one or more channels connecting the hollows to each other laterally, feeding the parisons into the hollows from the respective heads of the blow molding machine, and blowing air into the parisons in a manner such that a plurality of independent pipes are molded in the respective hollows and the pipes are joined with each other at the lateral walls thereof by the parisons which are forced into the channels upon air blowing. Suction forces are preferably applied on the parisons when the parisons are fed into the hollows of the molding die. The pipe unit thusly fabricated is light in weight and possesses flexibility as well as anti-corrosion properties due to the characteristics of the parisons.

Abstract: A method of fabricating a bundle-like pipe unit using a blow molding machine having a plurality of heads feeding parisons into a molding die includes the steps of forming a plurality of hollows independent from each other in the molding die, forming one or more channels connecting the hollows to each other laterally, feeding the parisons into the hollows from the respective heads of the blow molding machine, and blowing air into the parisons in a manner such that a plurality of independent pipes are molded in the respective hollows and the pipes are joined with each other at the lateral walls by the parisons which are forced into the channels upon air blowing. Suction forces are preferably applied on the parisons when the parisons are fed into the hollows of the molding die. The pipe unit thusly fabricated is light in weight and possesses flexibility as well as anti-corrosion properties due to the characteristics of the parisons.

Abstract: In disposing an insert or inserts within a blow-molded product, before the blow molding step is started, an inner supporting device supporting the insert at an end thereof is inserted into a parison and then the mold is closed so that the insert is made into contact with the parison. Thereafter the blow molding is effected so that the insert is securely welded to the parison.

Abstract: An extrusion head for use in blow molding machines for molding parison having a single layer or wall or a plurality of layers or walls, in which a plunger is slidably interposed between a head body and a core and the plastic material is successively accumulated in an accumulation chamber defined between the extruding end of the plunger, the head body and the core so that the faster the plastic material is introduced into the extrusion head, the faster it is extruded.

Abstract: A blow molding method and machine and more particularly a method and machine for extruding a multi-layer parison for blow molding, wherein at least two layers of molding plastics, each plastic compensating the poor or undesirable physical and chemical properties of the other plastic and/or each having a different color are forced to flow through different passages having an annular cross sectional configuration, and are joined at the junction of a short passage to be extruded into a multi-layer parison.

Abstract: A liquid containing abrasives is projected through nozzles under high pressure upon the surface of an object to be treated such as sheet steel to descale and clean the surface thereof, and the projected abrasive liquid is recovered so that abrasives of suitable particle sizes may be reused. The jet liquid is a mixture of high pressure liquid and slurry abrasives which are substantially uniform in density and granular size. The mixed slurry after projection against the sheet steel workpiece is returned to a vertical style classifier before it settles to the bottom of the collecting tank. The scales which are removed from the sheet steel workpiece are separated out in the classifier while at the same time the density and the granular sizes of the abrasives are made uniform. In addition, the minuscule abrasives are caused to overflow from the classifier while the liquid and the slurry abrasives made uniform in density and granular size are conveyed to the nozzles.