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
  • Request
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: Constant Flow Valve Principle
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
  • Request
Follow US
All rights reserved. Reproduction in whole or in part without written permission is prohibited.
Inst Tools > Blog > Control Valves > Constant Flow Valve Principle

Constant Flow Valve Principle

Last updated: January 24, 2019 2:29 pm
Editorial Staff
Control Valves
1 Comment
Share
3 Min Read
SHARE

Constant Flow Valve keep flow rate of gases or liquids at constant value even when the supply or load pressure changes.

Contents
Applications :1. Supply Pressure Variations2. Bubbler Level Measurement3. Purging for Orifice Plate Application

Constant Flow Valve

Control valve with diaphragm automatically acts following the change of pressure. They are normally delivered together with flowmeter as a “Purge set”.

Primary (Inlet) pressure variation control type and Secondary (Outlet) pressure variation control type are ready to meet all possible applications.

PRESSURE CONTROL VALVE

In the PRIMARY (INLET) PRESSURE VARIATION CONTROL TYPE, the fluid, of which inlet pressure varies, is introduced from IN to the lower chamber of the C series Constant Flow Valve.

The load pressure (Secondary pressure) is connected to the upper chamber. The differential pressure between the lower chamber and the upper chamber is always constant, thanks to the function of the Spring and the Diaphragm.

The differential pressure across the needle valve is kept always constant and the fl ow rate of the fluid is proportional only to the opening of needle valve.

Flow Control Valve

The opposite action is taken for SECONDARY (OUTLET) PRESSURE VARIATION CONTROL TYPE and the flow rate is kept also constant even when the load pressure changes.

Applications :

1. Supply Pressure Variations

Valve Supply Pressure Variations

As shown above, in case one large supply line branches into several lines and the supply pressure changes because of stoppage of some branches.

Primary Pressure Variation type Purge set will be suitable in keeping the purging volume of fl uid.

2. Bubbler Level Measurement

Bubbler Level Measurement

Liquid level in tanks is measured by the Back-pressure at the edge of purging pipe. The outlet pressure at the tank bottom changes depending on the liquid level, and constant bubbling is required.

Thus, Secondary Pressure Variation type purge set is used for this application. A DP transmitter is often connected to pressure line instead of pressure gauge for remote transmission.

3. Purging for Orifice Plate Application

Orifice Plate Purging

For the measurement of flow rate of corrosive liquids and/or liquids with solids by orifi ce plate, an equal pressure purging both to Hi and Lo pressure parts so as not to introduce liquid and/or solids into DP Pressure lead pipe. Dual mount type purge set used.

Source : tokyokeiso.co.jp

Articles You May Like:

Flow Nozzle Principle

Flow Standards

Control Valve Questions

Gas Valve Sizing

Needle Valves Applications

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

Valve Materials Comparison Notes
Basic Parts of Control Valves
Control Valve Testing for Noise Measurement
Solenoid Valves Types & Functions
Objective Questions on Valves
What is Mixing or Diverting Valve ?
Share This Article
Facebook Whatsapp Whatsapp LinkedIn Copy Link
Share
1 Comment
  • Gopal says:
    October 25, 2017 at 5:40 pm

    Which type of purging ( inlet Pressure or outlet pressure variation type) method used for measurement of flow and level?

    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

What is Instrument Air Manifold ?
Level Control Valve with Horizontal Float
Butterfly Valves – Concentric, Double-offset, and Triple-offset
Control Valve Recommended Practices for Harsh Process Conditions
How to Protect Pumps from Cavitation? – Reasons, Solutions
What is a Pilot Valve? When do we use a Pilot Valve?
What is a 2-way Solenoid Valve ?
Exclusive Control Valve Sequence

Keep Learning

Piping Schematic for Two Solenoid Valves Double Acting

Different Types of Control Valve Actuators

Erratic Stroking Control Valves

Erratic Stroking Control Valves Delaying the Shutdown Plant Restart

noise-abatement trim

Control Valve Noise Problems

Control Valves Questions and Answers

Control Valve Questions and Answers

double-ported globe valve

What is Double-ported Globe Valve ?

Control Valve Preventive Maintenance

Control Valve Preventive Maintenance

3-way directional control valves

Directional Control Valves Working Principle

Kv-value of a valve is determined by a standardised test

Calculate Flow Coefficient Kv of Solenoid Valve

Learn More

Overview of Tank Gauging Technologies

Control Valves Pre-Commissioning Checklist

Control Valves Pre-Commissioning Checklist

Electronic Devices & Circuits Objective Questions

Electronic Devices & Circuits Quiz – Set 2

Why is Motor Control Required in Control Systems

Why is Motor Control Required in Control Systems?

Spectrometers Questions and Answers

Total Reflection Spectrometer Questions & Answers

Pressure and Instrumentation MCQ - Questions & Answers

Pressure and Instrumentation MCQ – Questions & Answers

Target Flow Transmitter Problem

Target Flow Transmitters Failed the Very Midnight

DP Transmitter Problem

DP Transmitter Problem

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?