Design Calculators - Mechanical

World-Class P&ID Symbol Library for Mechanical Engineers

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Piping & Instrumentation Diagram (P&ID) Symbol Library

This library provides a comprehensive reference of standard P&ID symbols commonly used in mechanical, chemical, and process engineering across various industries. Adherence to these symbols is crucial for clear and consistent engineering diagrams, following international standards like ISA S5.1 and ISO 10628.

Browse through categories to find the symbols you need for piping, valves, pumps, heat exchangers, instrumentation, and more.

Lines & Connections

  • Process Line (Primary)
    Main process flow.
    ISA S5.1
  • Minor Process Line / Intermittent
    Secondary or intermittent flow.
    ISA S5.1
  • Pneumatic Signal Line
    Instrument signal (air).
    ISA S5.1
  • Electrical Signal Line
    Instrument signal (electrical).
    ISA S5.1
  • Data Link
    Digital communication link.
    ISA S5.1
  • Concentric Reducer
    Reduces pipe size concentrically.
    ISO 10628
  • Eccentric Reducer
    Reduces pipe size eccentrically.
    ISO 10628

Valves

  • Gate Valve
    For on/off service.
    ISA S5.1 / ISO 10628
  • Ball Valve
    Quarter-turn, on/off.
    ISA S5.1 / ISO 10628
  • Butterfly Valve
    Flow regulation/isolation.
    ISA S5.1 / ISO 10628
  • Globe Valve
    For throttling flow.
    ISA S5.1 / ISO 10628
  • Check Valve (Swing)
    Prevents backflow.
    ISA S5.1 / ISO 10628
  • Control Valve (Actuated)
    Regulates flow based on signal.
    ISA S5.1 / ISO 10628
  • Safety Relief Valve (PSV)
    Protects against overpressure.
    ISA S5.1 / ISO 10628
  • Diaphragm Valve
    For corrosive or abrasive fluids.
    ISO 10628
  • Plug Valve
    Quarter-turn valve for on-off service.
    ISO 10628
  • Angle Valve
    Globe valve with flow path at 90 degrees.
    ISO 10628
  • Three-Way Valve
    Directs flow to one of two outlets or mixes two inlets.
    ISO 10628
  • Needle Valve
    Precise flow control.
    ISO 10628
  • Check Valve (Lift / Piston)
    Prevents backflow, lifts with flow.
    ISO 10628

Pumps & Compressors

  • Centrifugal Pump
    Increases fluid pressure/flow.
    ISA S5.1 / ISO 10628
  • Positive Displacement Pump
    Displaces fixed fluid volume.
    ISA S5.1 / ISO 10628
  • Axial Compressor
    Compresses gas with axial flow.
    ISA S5.1 / ISO 10628
  • Fan / Blower
    Moves air or gas.
    ISA S5.1
  • Ejector / Jet Pump
    Uses fluid stream to pump another fluid.
    ISO 10628
  • Reciprocating Compressor
    Compresses gas using a piston.
    ISO 10628
  • Rotary Compressor
    Compresses gas using rotating elements.
    ISO 10628

Heat Exchangers & Furnaces

  • Heat Exchanger (General)
    Transfers heat between fluids.
    ISA S5.1 / ISO 10628
  • Shell and Tube Heat Exchanger
    Common type, uses tubes inside a shell.
    ISO 10628
  • Furnace / Fired Heater
    Heats process fluid using combustion.
    ISA S5.1
  • C
    Condenser
    Condenses vapor to liquid.
    ISO 10628
  • R
    Reboiler
    Vaporizes liquid at the bottom of a column.
    ISO 10628
  • Air Cooler / Fin Fan Cooler
    Cools fluid using ambient air.
    ISO 10628
  • Plate Heat Exchanger
    Transfers heat through plates.
    ISO 10628

Vessels & Tanks

  • Vertical Vessel / Tank
    For liquid or gas storage/processing.
    ISA S5.1 / ISO 10628
  • Horizontal Vessel / Drum
    For liquid or gas storage/separation.
    ISA S5.1 / ISO 10628
  • Cone Roof Tank
    Atmospheric storage tank.
    ISO 10628
  • Open Top Tank
    Tank open to atmosphere.
    ISO 10628

Instrumentation

  • PI
    Pressure Indicator (PI)
    Measures and displays pressure.
    ISA S5.1
  • TI
    Temperature Indicator (TI)
    Measures and displays temperature.
    ISA S5.1
  • FI
    Flow Indicator (FI)
    Measures and displays flow rate.
    ISA S5.1
  • LI
    Level Indicator (LI)
    Measures and displays liquid level.
    ISA S5.1
  • TC
    Temperature Controller (TC)
    Controls temperature automatically.
    ISA S5.1
  • PC
    Pressure Controller (PC)
    Controls pressure automatically.
    ISA S5.1
  • TR
    Temperature Recorder (TR)
    Records temperature over time.
    ISA S5.1
  • FR
    Flow Recorder (FR)
    Records flow rate over time.
    ISA S5.1

Filters & Separators

  • Filter (General)
    Removes solids from fluid.
    ISO 10628
  • LIQUID GAS
    Two-Phase Separator / Knockout Drum
    Separates two fluid phases.
    ISA S5.1 / ISO 10628
  • Cyclone Separator
    Separates solids/liquids from gases using centrifugal force.
    ISO 10628
  • Strainer
    Removes solid particles from a flowing liquid or gas.
    ISO 10628
  • Hydrocyclone
    Separates particles from liquids based on density.
    ISO 10628

Mixers & Agitators

  • Mixer / Agitator
    Blends or mixes fluids.
    ISO 10628

Conveyors & Solids Handling

  • Belt Conveyor
    Transports bulk materials.
    ISO 10628
  • Screw Conveyor / Feeder
    Transports bulk materials using a rotating helical screw.
    ISO 10628

Drives & Motors

  • M
    Electric Motor
    Converts electrical energy to mechanical.
    ISA S5.1 / ISO 10628
  • T
    Turbine
    Converts fluid energy to mechanical.
    ISO 10628
  • Gearbox / Speed Reducer
    Changes rotational speed and torque.
    ISO 10628

Process Equipment (General)

  • Column / Tower
    For distillation, absorption, etc.
    ISA S5.1 / ISO 10628
  • V
    Storage Tank (Generic)
    Generic tank for liquid storage.
    ISO 10628
  • Sieve Tray Column
    Distillation column with sieve trays.
    ISO 10628
  • E
    Evaporator
    Converts liquid to vapor for concentration.
    ISO 10628
  • CR
    Crystallizer
    Forms crystals from a solution.
    ISO 10628
  • DR
    Dryer
    Removes moisture from solids or gases.
    ISO 10628
  • B
    Boiler
    Generates steam by heating water.
    ISO 10628

Reactors

  • R
    Reactor (General)
    Generic symbol for a reactor.
    ISO 10628
  • CATALYST
    Fixed Bed Reactor
    Reactor with a stationary catalyst bed.
    ISO 10628

Safety Devices

  • Rupture Disk
    Non-reclosing pressure relief device.
    ISA S5.1 / ISO 10628
  • AL
    Alarm (General)
    Indicates an abnormal condition.
    ISA S5.1
  • SD
    Shutdown Device
    Initiates a shutdown sequence.
    ISA S5.1
  • FA
    Flame Arrestor
    Prevents flame propagation in pipes/tanks.
    ISO 10628
  • SS
    Safety Shower / Eyewash
    Emergency decontamination station.
    ANSI Z358.1

Piping Components

  • Expansion Joint
    Absorbs thermal expansion/contraction.
    ISO 10628
  • Steam Trap
    Discharges condensate and non-condensable gases without steam.
    ISO 10628