Lesson 13 - Control of Fluid Flow 3 SAQ
This lesson allows you to test yourself on the material covered in the Control of Fluid Flow 3 lesson and determine the level to which you have met the learning outcomes.
Suggested Response - Q2
***You are the cellar manager at a brewery where fermenter overpressure protection is achieved using spring-loaded mechanical pressure relief valves. An alternative option being proposed by a vendor is the use of bursting discs. What would your initial thoughts be on such a system? Give justifications.
(This is quite a far-reaching question. Try some searching on the internet and also discuss with brewery employees if you have a chance.)
Response:
Initial thoughts would include:
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A bursting disc is certainly a simpler design. It has no moving parts as a spring-loaded relief valve does which requires maintenance which may be attractive. However, discs degrade over time so need to be replaced regularly.
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A bursting disc is easier to clean as part of a vessel CIP. The seat and valve of a relief valve may require more complex cleaning, e.g. seat-lifting during vessel CIP which may not be effective enough.
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Bursting discs cannot be pressure tested in the same way as a relief valve can be. Think about it, if you test a bursting disc, then you cannot re-use it as you would have burst it.
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Once a bursting disc ruptures, the ruptured disc then becomes essentially an open hole in the top plate of the fermenter through which air and other contaminants can enter, and carbon dioxide can leave. If the disc is not replaced immediately, this situation can present a risk to product quality. In order to know when a disc ruptures, we must use a sensor system and have it incorporated into our control system, which adds extra complexity. A relief valve, on the other hand, should re-set itself and preserve the integrity of the fermenter contents.