Press-frame design

Given the eost eonstraints imposed on the press frame design, and the desire to minimize dimensional variation, the same material was seleeted for the eon-rod eross-seetion. To determine the dimension, D, using the same steel for the eon-rod ... 

Press frame designs Two different frame designs exist which are distinguished by the location of the press rollers in respect to the frame. 

Filter Press The filter press, one of the most frequently used filters in the early years or the chemical industry, is still widely employed. Often referred to genetically (in error) as the plate-and-frame filter, it has probably over 100 design variations. Two basic popular designs are the flush-plate, or plate-and-frame, design and the recessed-plate press. Both are available in a wide range of materials metals, coated metals, plastics, or wood. 

Figure 263. Photograph of a roller press with keyed and bolted mill-shaft frame design. (Courtesy of Koppern, Hattingen/Ruhr, FRG)...

Figure 266. Schematic representation of an alternate hinged frame design for small roller presses ...

The type of base frame is determined by the design of the piston extruder. The loads exerted on the base frame are mainly of a static nature and are governed by the weight of the components, especially that of the hydraulic cylinder and that of the receiver, moreover by the position of the press frame with the resulting difference in load situations for the base frame and foundation. 

Therefore the receiver support within the press frame must be of an amply sturdy design. 

The two basic materials used in press-frame structures are cast iron and steel fabrications. Stress-strain curves for cast iron or steel indicate that steel has a relative straight-line relationship to the yield point, whereas cast-iron yield is a fracture. However, reputable builders use design criteria in the 4000-5000-... 

The design of a vertical 600-ton tube press with a central piercer bar passing through the main plunger, is illustrated in Fig. 105 and 106. The two piercer cylinders are inserted in the press frame at either side of the... 

Filter presses are made in plate sizes from 10 by 10 cm (4 by 4 in) to 1.5 by 1.8 m (61 by 71 in). Frame thickness ranges from 0.3 to 20 cm (0.125 to 8 in). Operating pressures up to 689 kPa (100 psig) are common, with some presses designed for 6.9 MPa (1000 psig). Some metal units have cored plates for steam or refrigerant. Maximum pressure for wood or plastic frames is 410 to 480 kPa (60 to 70 psig). 

Both faces of each plate are hollowed to form a chamber for cake accumulation between adjacent plates. This design has the advantage of about half as many joints as a plate-and-frame press, making a tight closure more certain. Figure 18-114 shows some of the features of one type of recessed-plate filter which has a gasket to further minimize leaks. Air can be introduced behind the moth on both sides of each plate to assist cake removal. 

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