Support structure of plate-and-frame filter presses\nIn typical chemical plants, the main supporting legs/frame of a plate-and-frame filter press are generally constructed from which material?

Introduction / Context:
Plate-and-frame filter presses remain workhorses in solid–liquid separation for chemicals, food, and minerals. Their structural frame must withstand large hydraulic closing forces while being economical and durable, prompting common material choices for frames and supporting legs.

Given Data / Assumptions:

• The question refers to the main press frame/legs that bear mechanical load, not necessarily the wetted plates or cloths.
• Operating environments are typical industrial settings with basic corrosion control.

Concept / Approach:
Cast iron has historically been favored for the frames and supports of filter presses due to its high compressive strength, rigidity, good castability, and cost-effectiveness. While stainless steel is used for wetted components and special hygiene or corrosion services, the primary support structure in many standard installations remains cast iron or carbon steel. Wood is obsolete for structural frames in modern plants; high-speed steel is a tooling material, not a structural one; FRP lacks the stiffness for large closing loads in classic designs (though FRP can be used for corrosion-resistant components elsewhere).

Step-by-Step Solution:

Verification / Alternative check:
Legacy OEM catalogs and many installed units list “cast iron frame” or “cast steel frame” as standard offerings, with stainless optional for special-duty frames.

Why Other Options Are Wrong:

• Stainless steel: used but less common for main frames due to cost unless corrosion dictates.
• High-speed steel: inappropriate for structural frames.
• Wood: not used for modern industrial frames.
• FRP: insufficient stiffness for large presses.

Common Pitfalls:
Assuming the material of filter cloth/plates is the same as the frame; wetted and structural materials are chosen independently.

Final Answer:
Cast iron