Level measurement

96

Continuous level measurement in liquids

4. Instrument selection within the measuring principle

Installation instructions hydrostatics (differential pressure)

Closed tanks with Deltabar FMD71/FMD72 electronic dp • LP (low pressure) install sensor above the maximum measuring point • HP (high pressure) if possible, install sensor below the minimum measuring point • In case of outdoor installation it is recommended to mount the transmitter at a position where it is protected against the environment • It is recommended to install the pressure transmitter behind a stop valve to facilitate easy cleaning and functioning checks • Do not install the instrument in the following positions: – in the flow of product as it is filled – in the tank outlet – at a location in the tank which might be affected by the pressure impulses of the agitator • In case of media which might cure as they cool down, the instrument must be included in the insulation Foam of formation • Foam of formation does not have any noticeable influence on hydrostatic level measurement

max.

LP

p 2

Transmitter

min.

p 1

HP

C

Tank installations • Obstacles do not affect hydrostatic level measurement

Closed tanks with PMD78B (diaphragm seal plus side) • Always connect the minus side above the maximum level • Install Deltabar PMD78B directly at the tank below the lower measuring connection • Generally speaking, the installation of separators and discharge valves makes sense to collect deposits, pollution or liquids in the upper

max.

p 2

pressure piping and to remove them • Calibrate at operating temperature

min.

p 1