Laser-assisted dissociation: structural analysis of biomolecules

Contents

1. Liquid pressure gauges

1.1 U-tube

1.2 Micromanometers

1.3 Influence quantities

2. Solid-state pressure gauges

2.1 Diaphragm pressure gauges

2.2 Capsule pressure gauges

2.3 Bellows pressure gauges

2.4 Bourdon tube pressure gauges

2.5 Materials used

3. Manometric scales

4. Pressure gauges with electrical threshold detection

4.1 Electrical contact detection

4.2 Inductive detection

4.3 Microswitch control

4.4 Other devices

5. Choice of pressure gauges

The aim here is not to give a detailed, exhaustive description of the diversity of existing mechanical pressure gauges, but rather to place them in the general context of conventional pressure measurement. Specific technological aspects arising from the measurement of differential pressures or depressions will not be specifically addressed. Solutions for protection against harmful effects due to hostile environments or the characteristics of the fluid being controlled will be dealt with globally, i.e. with all instruments, in the fourth article.

Mechanical pressure gauges are mainly used for static (or quasi-static) measurements, and are designed to provide local information at the sampling site. They are characterized by their ergonomic readability - often used in supervisory software interfaces - and by their proven standardization, which makes them interchangeable. Aside from the fact that they still represent a major market share (replacing millions of mechanical pressure gauges installed worldwide), they are also becoming increasingly popular on sites where the use of electrical power is prohibited, and as verification instruments.

In their basic version, a distinction is made between liquid manometers and solid deformation manometers. The former are more or less derived from the U-shaped piezometer tube, while the latter are based on the principles of the deformable membrane and the Bourdon tube. They can be fitted with contacts (manometers with electrical threshold detection), or even with transmission devices, but in this case they are more akin to transmitters. Pressure balances are a separate category of pressure standards (primary and transfer).