Question

A set of symbols seen on P&IDs are shown in Figure P1.30. Identify all the instrument types and instrument connections (electrical, pneumatic, capillary).

Fibure P1.30

 

A Set of Symbols Seen on P&IDs, to Be Used in Problem 1.30

Answer 1

(a) A temperature (sensing) element (TE) in the plant is connected via a capillary line to a temperature transmitter (TT) also located in the plant. The TT sends an electrical signal to temperature high (TAH) and temperature low (TAL) alarms located on the front of a panel in the control room. 

(b) A level switch (LS) located in the plant sends an electrical signal to … 

(c) A pressure control valve (LCV) located in the plant is connected by a pneumatic (air) line to the stem of a control valve. 

(d) A local flow indicator (FI) is attached to a flow orifice both instruments are located in the plant.

(e) A safety (pressure) relief valve is shown attached to two process lines. The top process line appears to vent to atmosphere but could be attached to a flare system – there is not enough information to determine this based on the sketch provided.