Combination pressure head

Combination Pressure Head and Die Assemblies for Technical Ceramics... 

Fig. 2 Combination pressure head and die assemblies for ceramic monoliths...

Fig. 3 Laboratory production with a combination pressure head and die assembly for oval ceramic monoliths at 400 c.p.s.i.

Fig. 4 Combination pressure head and die assembly for experimental catalytic-converter monoliths used in diesel particulate control systems...

Of cotorse, the same criteria also apply to combination pressure head and die assemblies destined for use in the extrusion of profiles, tubes and multi-channel tubes optimal body feed from extruder to die. Any necessary internals, e.g., die-core plates and braces, must be designed and located such that they are sure not to initiate any shear textures in the column. 

Figure 10 is an exploded view of a standard combination pressure head and die assembly of the kind presently in widespread use for the manufacture of common building bricks. It comprises a slide-regulated pressure head and die. The die normally comprises a mounting (or front) plate, a die frame with a wear liner, a slide plate for regulating the column advance, and cores in a corebar. 

The combination pressure head and die assembly shown in figure 12 is in service at a number of plants. It produces as many as 12 columns at once, all well expressed and exhibiting minimal differences in column advance at penetrometric levels up to approximately 2.5. Of course, this presumes that the body is well-prepared and consistent. 

Example Combination Pressure Head and Die Assembly for use in the Manufacture of Thermal Insulating Bricks and Other Filigree Products... 

Figures 16 and 17 show a hydraulically optimized combination pressure head and die assembly for use in extruding roof-tile slugs. A flexible liner in the pressure head alters the feed contour to regulate the column advance. External control is possible by way of, say, a regulating screw during the ongoing extrusion process. This enables manipulation of the column flow without need of brakes.

In most cases, either a convenhonal type of combination pressure head and die assembly is used, or, depending on the properties of the body and on the requirements to he met hy the end product, a hydraulically optimized version. Smooth, streakless surfaces depend on fine-processed clays, hut the lack of coarse fractions in such clays makes them susceptible to lamination and structurahon. Shale clays are especially critical in this sense, because their clay parhcles tend to become oriented in the extrusion direction, with restrahfication of the column - a problem that often remains undetected until after firing. Hence, this aspect must always be given special attention in connechon with pressure heads and dies for split-tile extrusion. 

Figure 21 shows the makeup of a combination pressure head and die assembly of a kind now in widespread use for the manufacture of backing and facing bricks. It consists of ... 

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