Industrial furnaces can be heated electrically or using gas. Metal tools and components can be annealed and tempered via heat treatment in these furnaces.
The heat treatment processes in the furnaces should be carried out in a protective gas environment to avoid unnecessary chemical reactions such as combustion and oxidation. In addition, the furnaces should be devoid of formation of gases like helium, argon and nitrogen. However, the flow of protective gas into the furnace remains continuous to displace oxygen in presence of limited gauge pressure.
This article describes how KROHNE’s variable area flowmeter can measure protective gas reliably and accurately even at low operating pressure.
Measurement Conditions
The protective gas environment is created based on the adjustment and control of nitrogen in the range of 15 to 40Nm3/h. The 8bar gauge pressure is minimized to 100mbar in two steps.
The flowmeter is available with limited space carrying short outlet and inlet runs, facilitating compact installation.
The desired nitrogen flow is regulated by controlling the adjustment valve of a superimposed system by a 4...20mA current output signal.
KROHNE’s H 250 M40 Variable Area Flowmeter
KROHNE has introduced a DN50, H 250 M40 variable area flowmeter integrated with flange connections for measuring nitrogen.
The device features a local, analogue display without any power supply and a 4...20mA current output with 2-wire connection technology for controlling the adjustment valve. The measurement allows up to 1.6% measurement inaccuracy.
The H 250 M40 has an intelligent design which allows the integration of highly developed digital electronics.
.jpg)
Advantages of H 250 M40 Variable Area Flowmeter
Variable area flowmeters are widely used for measuring gases and liquids at low flow volumes. Unlike other measuring principles which require minimum flow velocity or density, variable area flowmeters are specifically designed for measuring gas flows with simultaneously low operating pressure.
Other key benefits include short inlet and outlet runs for easy installation, and low manufacturing and maintenance costs.
Key Features of H 250 M40 Variable Area Flowmeter
The main features of the H 250 M40 variable area flowmeter are:
- Measuring inaccuracy of 1.6% is allowed based on the VD! /VDE 3513, Bl. 2 IqG = 50%1
- Universal Ex concept: Ex i and Ex d
- A number of process connection variants available: weld-on ends, clamped, screwed, flanged, etc
- Rigid design withstands temperature and media resistance, and high pressure
- Unique and modular concept of mechanics
- Compact installation with short inlet and outlet runs
- Local analogue display ensures operation using 2-wire connection linking LCD, digital counter and current and binary outputs, or without power supply
Conclusion
This article discusses the technique used for reliably and precisely measuring protective gas with the help of KROHNE’s solution - H 250 M40 variable area flowmeter, its benefits and features.
About KROHNE Messtechnik GmbH
KROHNE is a world-leading manufacturer and supplier of solutions in industrial process instrumentation.
KROHNE offers supporting products and services for one-stop-shopping and in industries as widespread as oil & gas, water & wastewater, chemical & petrochemical, food & beverage, power, minerals & mining and marine.
This information has been sourced, reviewed and adapted from materials provided by KROHNE Messtechnik GmbH.
For more information on this source, please visit KROHNE Messtechnik GmbH.