Compared with a plate-and-frame filter press, a shell-and-leaf (pressure leaf) filter typically offers which combination of advantages in operation?
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ALess labor cost
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BFiltration under higher pressure
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CMore effective washing
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DAll (a), (b) & (c)
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ENone of these
Answer
Correct Answer: All (a), (b) & (c)
Explanation
Introduction / Context:Filter selection balances labor, pressure capability, washing efficiency, and ease of cake discharge. Pressure leaf (shell-and-leaf) designs differ significantly from plate-and-frame presses.
Given Data / Assumptions:
- Vertical or horizontal pressure leaf units are considered.
- Batch operation with precoat or body feed possible.
Concept / Approach:Pressure leaf filters provide enclosed operation at relatively high pressures, allow uniform cake washing by spray or reslurry, and often require less manual labor than opening and cleaning a plate-and-frame press. Cake discharge can be automated by vibration or sluicing.
Step-by-Step Solution:Assess labor: leaf filters minimize manual plate handling.Assess pressure: designed for high-pressure service.Assess washing: improved access to cake surfaces and spray washing.
Verification / Alternative check:Manufacturer literature highlights reduced OPEX and improved CIP/cleanability for pressure leaf units.
Why Other Options Are Wrong:Single benefits only: understates the combined advantages.
Common Pitfalls:Comparing only cloth cost without considering labor downtime for press opening/closing.
Final Answer:All (a), (b) & (c)