Elastic pressure gauges: which sensing element form is never used as the primary elastic member?

Introduction / Context:
Elastic pressure gauges convert fluid pressure into mechanical deflection using elastic elements. Common types include Bourdon tubes, diaphragms, and bellows. Recognizing which geometries are actually employed helps avoid design misconceptions and ensures correct selection for pressure range and media.

Given Data / Assumptions:

• An “elastic element” must flex under pressure-induced stress and translate it into measurable motion.
• Industrial families: Bourdon tube (C-type, helical, spiral), diaphragm, bellows.
• We are selecting the form that is not used as the elastic pressure-sensing element.

Concept / Approach:
Bourdon tubes are curved hollow sections that uncoil with internal pressure. Diaphragms are thin circular membranes that deflect with differential pressure. Bellows are convoluted cylinders expanding axially under pressure. A simple “strip” (solid bar) does not provide the hollow, pressure-containing geometry required to translate internal pressure into useful elastic deformation for measurement; it lacks an internal cavity and suitable sensitivity.

Step-by-Step Solution:

Verification / Alternative check:
Instrument catalogs and standards (e.g., ASME/EN) classify pressure elements exclusively as Bourdon, diaphragm, or bellows (and variants), confirming that “strip” is not a category.

Why Other Options Are Wrong:

Common Pitfalls:
Confusing temperature-sensing bimetal “strips” with pressure-sensing elastic elements; they are different instrument classes.

Final Answer:
strip