API RP 550-1-12-1977 PDF

Scope: This section discusses recommended practices for the installation of the more commonly used instruments and devices for indicating@ recording@ and controlling liquid levels and liquid-liquid interface levels normally encountered in petroleum refinery processes. The types of instruments covered are: 1. Locally mounted indicating gages (Par. 2.3)@ including tubular gage glasses@ armored-type gage glasses@ float-and-cable (automatic) tank gages@ hydrostatic head pressure gages@ and differential pressure level indicators. 2. Level transmitters (Par. 2.4)@ including displacers@ differential pressure types@ hydrostatic head types@ and electric and electronic types. 3. Locally mounted controllers (Par. 2.5)@ including displacers@ ball floats@ and differential pressure types. 4. Remote or panel-mounted receivers (Par. 2.6). 5. Level alarms (Par. 2.7). 6. Accessories (Par. 2.8)@ including seals and purges@ gage glass illuminators@ and weather protection.

API RP 550-1-12-1977 history

1977 API RP 550-1-12-1977 Manual on Installation of Refinery Instruments and Control Systems - Part I - Process Instrumentation and Control Section 2-Level (Third Edition)