Which primary element is robust for moderate pressures in pressure transmitters?

Which primary element is robust for moderate pressures in pressure transmitters?

• A. Capsule
• B. Diaphragm
• C. Bourdon Tube
• D. Bellows

Answer: (C)

When a pressure transmitter needs to measure moderate pressures with rugged durability, a Bourdon tube is a natural choice. The sensing element is a curved, elastic tube that tends to straighten as internal pressure increases. This simple, robust geometry converts pressure into a predictable mechanical motion with good overpressure tolerance and resistance to misalignment, making it durable in everyday process conditions. Because it relies on straightforward elastic deformation rather than thin membranes or highly folded components, it handles shocks, vibrations, and pressure surges well, which is ideal for moderate ranges where rugged performance matters. Other elements are more sensitive or more prone to fatigue. A capsule uses a sealed membrane assembly and excels at very low pressures but isn’t as robust at higher moderate pressures. A diaphragm provides high sensitivity with thin membranes, but the membrane can fatigue or yield under overpressure, reducing durability. Bellows offer fine, high-sensitivity measurements but involve more complex, fatigue-prone folded structures that are less rugged under typical process conditions.

When a pressure transmitter needs to measure moderate pressures with rugged durability, a Bourdon tube is a natural choice. The sensing element is a curved, elastic tube that tends to straighten as internal pressure increases. This simple, robust geometry converts pressure into a predictable mechanical motion with good overpressure tolerance and resistance to misalignment, making it durable in everyday process conditions. Because it relies on straightforward elastic deformation rather than thin membranes or highly folded components, it handles shocks, vibrations, and pressure surges well, which is ideal for moderate ranges where rugged performance matters.

Other elements are more sensitive or more prone to fatigue. A capsule uses a sealed membrane assembly and excels at very low pressures but isn’t as robust at higher moderate pressures. A diaphragm provides high sensitivity with thin membranes, but the membrane can fatigue or yield under overpressure, reducing durability. Bellows offer fine, high-sensitivity measurements but involve more complex, fatigue-prone folded structures that are less rugged under typical process conditions.