Process Flow Diagram Symbols and Their Usage

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Do You Want to Create Your Process Flow Diagram?

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Process flow diagrams use special shapes to represent different types of equipments, valves, instruments and piping flow. This article provides plenty of process flow diagram symbols and helps you to understand and create process flow diagrams easily and quickly.

EdrawMax includes standard sets of symbols depicting mechanical equipment, piping, piping components, valves, equipment drivers, instrumentation, and controls. These PFD symbols are assembled on the drawing in a manner that clearly defines the process flow diagrams. With the pre-made PFD symbols in EdrawMax, you can make a process flow diagram in minutes!

Process Flow Diagram Symbols

What is a Process Flow Diagram?

The Process Flow Diagram is a graphical representation used to demonstrate major components of a process in an Industrial plant or manufacturer, it is widely used in Chemical/petroleum or process engineering.

The Process flow diagrams are used to understand the process and its sequence, model a process, document a process, ensure quality control and standards plus increase efficiency. It maps out the whole process from scratch to show how equipment and chemicals work in the plant. It is a visual way of stating a process, it includes tasks, steps with their sequence.

What's Included in a Process Flow Diagram?

A process flow diagram includes:

  • Equipment
  • Valves
  • Piping Lines
  • Instruments
  • Centrifuges
  • Heat Exchang
  • Crushers

And there are detailed introduction to these symbols below, you can learn them with symbols image.


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Process Flow Diagram Symbols - Equipment

Pumps and tanks come in a variety of designs and shapes.

Process Flow Diagram Symbols - Equipment

Compressor is a mechanical device that takes in a medium and compresses it to a smaller volume. A mechanical or electrical drive is typically connected to a pump that is used to compress the medium.

Pump refers to a mechanical apparatus using suction or pressure to raise or move liquids, compress gases, or force air into inflatable objects such as tires. The symbols for pumps may closely resemble those for compressors.

Mixing is a gear that combines some materials or put them together to form one substance or mass.

Mixing vessel is a container that is used to blend several components.

Process Flow Diagram Symbols - heat exchanger

Heat exchanger is used to transfer heat energy between two process flows. Heat exchangers transfer heat energy through conductive and convective heat transfer.

Cooling towers transfer heat energy to the outside air through the principle of evaporation.

Cooler is a device, container, or room that cools air through the evaporation of water or keeps cool.

Furnace means a tool for heating a continuous current of air through a fire within the apparatus and without mingling the fresh air with the products of combustion.

Boiler is a closed vessel in which water or other fluid is heated.

Tank is used to store process fluids of various types under different process conditions.

Part 3: Process Flow Diagram Symbols - Valves

Process Flow Diagram Symbols - Valves

Gate valve is a device used to control the flow of liquids and gases.

Check valve, also known as a one-way valve, is to prevent the line of medium back.

Globe valve refers to a mechanism used to control or stop liquid or gas flow through a pipe.

Ball valve is a valve with a spherical disc, the part of the valve which controls the flow through it.

Butterfly valve is installed between two flanges using a separate set of bolts for each flange.

Angle valve is oriented at a 90 deg angle of the gate valve.

Needle valve has a slender, tapered point at the end of the valve stem that is lowered through the seat to restrict or block flow.

Control valve is the valve used to control conditions such as flow, pressure, temperature, liquid level, etc.

Relief valve (RV) is a type of valve used to control or limit the pressure in a system or vessel.

Bleeder valve works by releasing air, or gas through a valve opening to reduce the built up pressure inside a tank or remove excess air or gas in a system.

Part 4: Process Flow Diagram Symbols - Piping Lines

Process flow diagrams use special piping lines to represent how signals are transmitted between equipments. These symbols are used to identify how the instruments in the process connect to each other. And what type of signal is being used. (electrical, pneumatic, data, etc)

Process Flow Diagram Symbols - Piping Lines

All lines are fine in relation to process piping lines.

Major pipeline is for the connection of the equipment in any position.

Major Straight line issued to connect the equipment in the same horizontal or vertical position.

Process connection help to create the process flow between equipment. Double click process connection to edit the description.

Flange is a projecting flat rim, collar, or rib on an object, serving for strengthening or attachment or (on a wheel) for maintaining position on a rail.

Reducer is the component in a pipeline that reduces the pipe size from a larger to a smaller bore (inner diameter).

Part 5: Process Flow Diagram Symbols - Instruments

Process Flow Diagram uses symbols and circles to represent each instrument and how they are inter-connected in the process.

Process Flow Diagram Symbols - Instruments

Indicator is a thing that indicates the state or level of something.

Thermomter is an instrument for measuring and indicating temperature.

Flow transmitter is a device used as a means of measuring the flow of a specific substance, usually liquid, through a series of pipelines or tubing.

Pressure transmitter is used to measure pressure, typically of gases or liquids.

Pressure recorder, as its name implies, is used to record the pressure.

Users can easily change types of instrumentation symbols by clicking the quick action button while designing.

Smart instrumentation symbols

Part 6: Process Flow Diagram Symbols - Centrifuges

A centrifuge is a device whose function is to extract insoluble particles from a solution through spinning on the basis of multiple factors including size, density, viscosity, shape of the medium and rotor speed.

Process Flow Diagram Symbols - Centrifuges


  • Benchtop centrifuge
  • Continuous flow centrifuge
  • Refrigerated centrifuges
  • Hematocrit centrifuge
  • High speed centrifuge
  • Low speed centrifuge
  • Gas centrifuge
  • Micro centrifuge

Part 7: Process Flow Diagram Symbols - Heat Exchangers

Process Flow Diagram Symbols - Heat Exchangers

Heat exchangers are devices that are used for transferring thermal energy from one fluid or gas to another one, when the two fluids are physically separated or blocked by a wall. It can be used for both heating and cooling purposes. The main use or purpose of this device is the transfer of heat from one medium to another, and it is also used for cooling purposes.


  • Shell and tube heat exchangers.
  • Double pipe heat exchangers.
  • Condensers, evaporators, and boilers.
  • Plate heat exchangers.

Part 8: Process Flow Diagram Symbols - Crushers

Crushers are machines that are used to reduce the size of heavy rocks, stones and ores into a desired shape and form. They are widely used in aggregate production, construction, recycling and in mining purposes. Crushers are used in industrial processes where machines use a metal surface to break or compress or deform materials into small fractional shapes or denser masses.

Process Flow Diagram Symbols - Crushers


  • Jaw crushers
  • Gyratory crushers
  • Cone crushers
  • Compound crusher
  • Crusher buckets
  • Jaw crushers
  • Mineral sizers
  • Vertical shaft impactors

Part 9: Use EdrawMax for Easy Process Flow Diagram Creation

EdrawMax provides an extensive range of symbol libraries. They are compatible with most of the mechanical and industrial requirements needed in piping, instrumentation, and all the required processes.

Process Flow Diagram Software

A Process flow diagram consists of a set of basic symbols to represent various functions, steps or phases and shows the sequence and interconnection of functions with lines and arrows between steps. It helps project stakeholders and members to identify the different phases of a process and understand the connections among them.

EdrawMax is Pro industrial, chemical, production or business process documentation software for making process flow diagrams, workflow diagrams, general flowcharts and technical charts by providing thousands of worthy templates. The flowchart or the diagram created in EdrawMax consists of graphical keys and notations including symbols, interface points, labels, callouts and textboxes to describe every phase and step of the process.

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