Inst ToolsInst ToolsInst Tools
  • Courses
  • Automation
    • PLC
    • Control System
    • Safety System
    • Communication
    • Fire & Gas System
  • Instrumentation
    • Design
    • Pressure
    • Temperature
    • Flow
    • Level
    • Vibration
    • Analyzer
    • Control Valve
    • Switch
    • Calibration
    • Erection & Commissioning
  • Interview
    • Instrumentation
    • Electrical
    • Electronics
    • Practical
  • Q&A
    • Instrumentation
    • Control System
    • Electrical
    • Electronics
    • Analog Electronics
    • Digital Electronics
    • Power Electronics
    • Microprocessor
Search
  • Books
  • Software
  • Projects
  • Process
  • Tools
  • Basics
  • Formula
  • Power Plant
  • Root Cause Analysis
  • Electrical Basics
  • Animation
  • Standards
  • 4-20 mA Course
  • Siemens PLC Course
Reading: Air Consumption Calculation for ON/OFF Valves
Share
Notification Show More
Font ResizerAa
Inst ToolsInst Tools
Font ResizerAa
  • Courses
  • Design
  • PLC
  • Interview
  • Control System
Search
  • Courses
  • Automation
    • PLC
    • Control System
    • Safety System
    • Communication
    • Fire & Gas System
  • Instrumentation
    • Design
    • Pressure
    • Temperature
    • Flow
    • Level
    • Vibration
    • Analyzer
    • Control Valve
    • Switch
    • Calibration
    • Erection & Commissioning
  • Interview
    • Instrumentation
    • Electrical
    • Electronics
    • Practical
  • Q&A
    • Instrumentation
    • Control System
    • Electrical
    • Electronics
    • Analog Electronics
    • Digital Electronics
    • Power Electronics
    • Microprocessor
Follow US
All rights reserved. Reproduction in whole or in part without written permission is prohibited.
Inst Tools > Blog > Instrumentation Design > Air Consumption Calculation for ON/OFF Valves

Air Consumption Calculation for ON/OFF Valves

Last updated: May 26, 2019 9:25 pm
Editorial Staff
Instrumentation Design
9 Comments
Share
2 Min Read
SHARE

Air Consumption Calculation for ON/OFF Valves

Generally we specify air consumption in SCFM ( standard cubic feet per minute) for on/off valve as an intermediate (Non-continuous) service.

Air Consumption calculation for ON/OFF valves are given in liters by many European actuator vendors and Process Engineer demands consumption in SCFM. (I faced this in one project here)

Now let us learn how we can calculate the consumption in SCFM from Liters .

Actuator Manufactures select actuator based on Valve details and Torque Valves and selected actuator Displacement volume is in Liters (capacity)

1) ESDV -100 with 18″ full bore 900 RTJ size , Selected actuator is having 160.15 Liter (Displacement volume)

2) Convert the actuator displacement volume, Liter in SCF (standard cubic feet)

1L = 0.035315ft³

160.15 Liter – 5.65 ft³

3) Now ESDV is fail close valve and air consumption is more during opening of the valve ( actuator volume gets filled) and valve closing time for ESDV-100 is say 54 Sec (3 Sec per inch)

Actuator volume 5.65 cubic feet has to be filled in 54 sec (Air consumption)

Per second air consumption is 5.65 / 54 = 0.1046 Cubic Feet per second

Now convert this in Minutes

0.1046 CFS = 6.276 Cubic Feet Minute.

It shall be noted that air consumption always depends on air supply pressure and need to be specified as SCFM @ air supply pressure.

Credits : VINAYAK DUMBRE

Don't Miss Our Updates
Be the first to get exclusive content straight to your email.
We promise not to spam you. You can unsubscribe at any time.
Invalid email address
You've successfully subscribed !

Continue Reading

Basics of Permissive and Interlock Circuits
Motor Control Signal Interface
Interface Level Measurement Selection Guide
4-20 mA Loop Splitter
Failsafe Wiring Practices
Thermowell Insertion and Immersion Length
Share This Article
Facebook Whatsapp Whatsapp LinkedIn Copy Link
Share
9 Comments
  • David Sirjue says:
    June 7, 2018 at 9:13 pm

    The last sentence need to be checked for accuracy. SCFM references volume at standard conditions of temperature and atmospheric pressure so ‘SCFM @ air supply pressure’ is contradictory.

    Reply
  • azetou says:
    July 16, 2019 at 7:01 pm

    was gonna write this and then I saw your comment

    Reply
  • jagadish bhushi says:
    December 4, 2019 at 6:36 am

    What is normal pnematic On/off valve sizes say100 nb,150nb,200nb

    Reply
  • Aquatech Systems says:
    January 28, 2020 at 5:50 pm

    Anyone please suggest how to calculate compressor capacity for pneumatic valves.

    Reply
  • Karik says:
    April 24, 2020 at 1:36 pm

    This is incorrect calculation. The air will be consumed during the opening process, not closing which is venting to ATM. Also the volume is not converted into standard condition.

    Reply
  • Kris K says:
    October 26, 2022 at 1:53 am

    This is not correct. If the air consumption is sized like this for every valve in the plant, you will need a giant air compressor. The calculation for air consumption would be:

    Actuator Vol / cycle x no of expected cycles per hr or day
    In this case the valve needs 5.65 ft3 say at 80 psig (convert this into std conditions) = 33 SCF and the valve opens once per hr this valve consumes require 33 SCF/hr on average. For peak Conditions add a factor to size the total consumption. Ensure the accessories can handle the peak flow (6.276 SCFM) for the max specified Pressure Drop.

    Reply
  • Pruthviraj Suryawanshi says:
    December 27, 2022 at 10:36 am

    This calculation in incorrect. Because we cant consider displacement volume , we have to understand that compressed air can be stored more or less within that displacement volume as per air pressure. Lets consider an example. If you have 1 bottle having 1 L volume then @ 4bar this bottle can store say 3L air but @ 5bar same bottle can store about 4L air. So, to calculate air consumption you must consider an Air pressure. Please find attached calculation for more understanding.

    air consumption for one cycle in L/stroke = volume of actuator for open stroke in L x (( air pressure in bar +atmospheric air pressure in bar )/atmospheric air pressure in bar)

    Kindly note that in single acting actuator, closing or backward motion needs no air supply this stroke is achieved by spring force Hence for spring return actuator, no need to consider closing stroke air consumption. For double acting actuator you must have to consider.

    To convert this in to Litres per hour you must know operating time of actuator. Assume that opening time is 5 sec & closing time is also 5 sec then total operating time for spring return/single acting actuator will be 10 sec for 1 complete cycle.

    for Double acting actuator,
    total air consumption for one cycle = air consumption for opening stroke + air consumption for closing stroke

    air consumption in LPH=(air consumption for one cycle/total operating time)x3600
    air consumption in LPM=(air consumption for one cycle/total operating time)x60

    Now you can convert it to any unit easily through any calculator on google.

    Reply
  • arun says:
    December 28, 2022 at 11:34 am

    Dear Pruthviraj,

    But finally not conclude air compressor sizing selection or consumption calculation in statement.

    please advice for Double acting actuator.

    Reply
    • Pruthviraj Suryawanshi says:
      January 4, 2023 at 6:21 pm

      Dear Arun,

      for double acting actuator,
      air consumption for opening stroke= volume of actuator for open stroke in L x (( air pressure in bar +atmospheric air pressure in bar )/atmospheric air pressure in bar)

      air consumption for closing stroke= volume of actuator for close stroke in L x (( air pressure in bar +atmospheric air pressure in bar )/atmospheric air pressure in bar)

      Air consumption for one cycle in L/stroke =air consumption for opening stroke + air consumption for opening stroke

      air consumption in LPH=(air consumption for one cycle/total operating time)x3600
      air consumption in LPM=(air consumption for one cycle/total operating time)x60

      for higher than 55CFM or 76410 LPH
      Screw type Compressor sizing= summation of all actuator & pneu. eqp. air consumption x factor of safety 1.4

      for less than 55CFM or 76410 LPH
      for piston type Compressor sizing= summation of all actuator & pneu. eqp. air consumption x factor of safety 1.6

      You may not found exact required compressor in market hence consider higher available compressor model.

      Reply

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Stay Connected

128.3kFollowersLike
69.1kFollowersFollow
210kSubscribersSubscribe
38kFollowersFollow

Categories

Explore More

Instrument Process Datasheet (IPDS)
Diaphragm Seal Material Selection
Cut-outs between Platforms or Grating for Field Instruments
Thermowell Installation near Critical Equipment
Cable Routing
Control Valve Recommended Practices for Harsh Process Conditions
How to Select a Conductivity Meter
Package Control and Safety Systems Implementation Methods

Keep Learning

Analog signal with noise

Signal Coupling and Cable Separation

Instrumentation and Control General Specifications

Instrumentation and Control (I&C) General Specifications

Instrument Air (IA) System

Process Design of Instrument Air System

Guided Wave Radar Level Transmitter Compensation

Guided Wave Radar Level Sensor Pressure and Temperature Effects

Motor Primary Resistance Starter

Electrical Motor Starter Circuits

Pressure Gauge Problems

Pressure Gauge Problems

Instrumentation Earthing

Instrumentation Earthing

pressure switch control two lamps wiring

Draw Wiring of a Pressure Switch to control two lamps

Learn More

Why Grounding

Basics of Grounding

Motor Disconnector Switch

What is a Motor Disconnector Switch? – Purpose, Principle, Factors

Instrument Air (IA) System

Process Design of Instrument Air System

Programmable Logic Controller (PLC)

What is Interposing Relay in a PLC System ?

P&ID

Over Pressure Protection Devices

Digital Electronics MCQ

Logic Gates and Networks Objective Questions

TON Timer in RSlogix

Why is RTO used in the Place of TON Timer?

Types of Failures in Control Valves

Types of Failures in Control Valves

Menu

  • About
  • Privacy Policy
  • Copyright

Quick Links

  • Learn PLC
  • Helping Hand
  • Part Time Job

YouTube Subscribe

Follow US
All rights reserved. Reproduction in whole or in part without written permission is prohibited.
Welcome Back!

Sign in to your account

Username or Email Address
Password

Lost your password?