LOW-P-FLOW Mass Flow Meters/Controllers0 pages

> Introduction
Bronkhorst High-Tech B.V., the European market leader in thermal
Mass Flow Meters/Controllers and Electronic Pressure Controllers,
has more than 25 years experience in designing and manufacturing
precise and reliable measurement and control devices. With a wide
range of instruments, Bronkhorst High-Tech offers innovative solutions
for many different applications in many different markets.
The instruments are made to customers’ specification, in various
styles, suitable for use in laboratory, industrial and hazardous
areas, in such diverse applications as semiconductor and
analytical installations, to name but two.
> LOW-ÄP-FLOW series for low pressure
drop or corrosive gases
In a number of applications for measuring and controlling gas
flows there is only little differential pressure available and/or allowable.
These are the applications for which Bronkhorst High-Tech
developed the LOW-ÄP-FLOW series, in which the flow resistance
is minimised by using a large bore capillary (thermal bypass sensor)
in combination with a cylindrical flow splitter (laminar flow
element). Based on this concept, mass flow capacities between
0…10 mln/min and 0…1000 m3
n/h can be measured. At a flow
up to 2 ln/min a pressure drop of less than 1 mbar is required.
Furthermore the larger flow channels minimise the risk of clogging
and facilitate the cleaning and purging of these LOW-ÄP-FLOW
instruments, which will contribute to a significantly longer lifetime
when the instruments are used on corrosive gas service. All fluid
wetted parts are of electro-polished stainless steel. Optionally the
flow meter body, sensor and flow element can be supplied in
Hastelloy or Monel.
> For laboratory or industrial conditions
The LOW-ÄP-FLOW series are derived from the laboratory style
EL-FLOW series, however they can also be supplied with a rugged
IP65 (dust and waterproof) IN-FLOW housing, suitable for industrial
environments. The latter are also ATEX Category 3, approved for
use in Zone 2 hazardous areas. In addition to the standard analog
I/O-signals and the RS232 connection, there is the possibility of
integrating an interface board with DeviceNetTM, Profibus-DP®,
Modbus-RTU or FLOW-BUS protocol.
> Mass flow control with low differential
pressure
The control of mass flow with small pressure difference comprises
the LOW-ÄP-FLOW Mass Flow Controllers in compact construction
(model series F-200/201/202). The integrated proportional, electromagnetic
control valves of these MFC’s have extremely fast and
smooth control characteristics. Depending on the operating
properties, the maximum flow in these models is 1…50 ln/min
air-equivalent.
For the control of higher flow rates at very low differential pressures
Bronkhorst High-Tech have devised special control valves with
pressure compensation bellows (series F-004). These control
valves are close-coupled to the flow meter while the electric
PI-control function is an integral part of the flow meter. This F-004
valve has proven to be an excellent alternative to large, slow and
expensive servo driven valves.
> LOW-ÄP-FLOW features
u very low pressure drop
u suitable for corrosive gases
u wetted parts: electro-polished stainless steel; other on request
u also available with IP65 housing, ATEX approval Cat.3, Zone 2
u analog and digital (fieldbus) communication
u alarm and counter functions
LOW-ÄP-FLOW
Mass Flow Meters/Controllers for
low pressure drop or corrosive gas service