1. Latest News
  2. Submit Press Release
  1. PR Home
  2. Latest News
  3. Feeds
  4. Alerts
  5. Submit Free Press Release
  6. Journalist Account
  7. PRNewswire Distribution
Mass Flow Measurements of Liquids Logo

Omkar_Walambe_Flow_Launches New Animations For Flow Measurement Instrument Understanding Part-1

Understanding Everything Related To Thermal Mass Flowmeter Right From A to Z

FOR IMMEDIATE RELEASE

 
 
thermal
thermal
PRLog (Press Release) - Oct. 17, 2012 - There are two types of thermal flow meters in industry. Industrial thermal mass flow meters, also known as thermal dispersion or immersible mass flow meters comprise a family of instruments for the measurement of the total mass flow rate of a fluid, primarily gases, flowing through closed conduits. A second type is the capillary-tube type of thermal mass flow meter. Many mass flow controllers (MFC) which combine a mass flow meter, electronics and a valve are based on this design.

Both types measure fluid mass flow rate by means of the heat convected from a heated surface to the flowing fluid. In the case of the thermal dispersion, or immersible, type of flow meter, the heat is transferred to the boundary layer of the fluid flowing over the heated surface. In the case of the capillary-tube type, the heat is transferred to the bulk of the fluid flowing through a small heated capillary tube. The principles of operation of the two types are both thermal in nature, but are so substantially different that two separate standards are required. Additionally, their applications are much different. Thermal dispersion flow meters are commonly used for general industrial gas flow applications in pipes and ducts, whereas capillary types are primarily used for smaller flows of clean gases or liquids in tubes. This type is most widely used for thermal mass flow meters in industry. Nevertheless, the capillary type is not the subject of this discussion.

Thermal Dispersion Mass Flow Meters

The operation of thermal dispersion mass flow meters is attributed to L.V. King who, in 1914, published his famous King's Law revealing how a heated wire immersed in a fluid flow measures the mass velocity at a point in the flow. King called his instrument a "hot-wire anemometer". However, it was not until the 1960s and 1970s that industrial-grade thermal dispersion mass flow meters finally emerged.

How Thermal Mass Flow Meters Work

Thermal mass flow meters are used almost entirely for gas flow applications. As the name implies, thermal mass flow meters use heat to measure flow. Thermal mass flow meters introduce heat into the flow stream and measure how much heat dissipates using one or more temperature sensors. This method works best with gas mass flow measurement. It is difficult to get a strong signal using thermal mass flow meters in liquids, due to considerations relating to heat absorption.

While all thermal flow meters use heat to make their flow measurements, there are two different methods for measuring how much heat is dissipated. One method is called the constant temperature differential. Thermal flow meters using this method have two temperature sensors — a heated sensor and another sensor that measures the temperature of the gas. Mass flow rate is computed based on the amount of electrical power required to maintain a constant difference in temperature between the two temperature sensors.

A second, and less popular concept, is called a constant current method. Thermal mass flow meters using this method also have a heated sensor and another one that senses the temperature of the flow stream. The power to the heated sensor is kept constant. Mass flow is measured as a function of the difference between the temperature of the heated sensor and the temperature of the flow stream. Both methods are based on the principle that higher velocity flows result in a greater cooling effect. Both measure mass flow based on the measured effects of cooling in the flow stream.

Industrial Applications

The primary reason thermal mass flow meters are popular in industrial applications is the way they are designed and built. They feature no moving parts, nearly unobstructed straight through flow path, require no temperature or pressure corrections and retain accuracy over a wide range of flow rates. Straight pipe runs can be reduced by using dual-plate flow conditioning elements and installation is very simple with minimal pipe intrusions.

Photo:
http://www.prlog.org/12001663/1

--- End ---

Click to Share

Contact Email:
***@measurementsystemsindia.com Email Verified
Source:Omkar_Walambe_P_Mass_Flow_Measurements_Of_Liquids
Phone:9370078081
Zip:412105
City/Town:Pune - Maharashtra - India
Industry:Business, Industrial
Tags:Omkar Walambe, Omkar_Walambe_Company, Omkar_Pune_Walambe, Omkar_Walambe_Pune, Omkar_Walambe_India
Shortcut:prlog.org/12001663
Disclaimer:   Issuers of the press releases are solely responsible for the content of their press releases. PRLog can't be held liable for the content posted by others.   Report Abuse

Latest Press Releases By “

More...

Trending News...



  1. SiteMap
  2. Privacy Policy
  3. Terms of Service
  4. Copyright Notice
  5. About
  6. Advertise
Like PRLog?
9K2K1K
Click to Share