HFM-D-300/HFC-D-3020 pages

www.teledyne-hi.com
TELEDYNE HASTINGS INSTRUMENTS
MODELS
HFM-D-300
HFC-D-302
FEATURES
• Flows from 0-5 sccm (N2 Equivalent)
up to 0-25 slm (N2 Equivalent)
• Accuracy in Nitrogen ± (0.2% of Full scale +
0.5% of Reading)
• All Metal Seals, Kalrez® Valve Seat
• Flexible Operation with ±12, ±15 or 24 VDC
Power Supply
• RS232/485
• Auto-Zero (HFC-302 Flow Controller Only)
• Self-Diagnostics –Sensor, Valve and Overflow
• Analog or Digital Control and Indication
• Can Store Up To 10 Gas Calibrations
• Can Provide Totalized Flow
• Can Provide Alarms
APPLICATIONS
• Process gases
• Industrial gas distribution
• Petrochemical
• Fuel cell testing
• Pharmaceutical production
• Secondary calibration reference
• Gas generation
BENEFITS
• Enhanced Accuracy
• Superior Linearity
• Digital Communications
• Metal Seals
Digital 300 Series - Low Capacity
DESCRIPTION
The Teledyne Hastings Instruments Digital Metaline thermal
mass flow meter or controller complements an extensive
array of wide-ranged analog flow instruments.
The heart of the instrument is the same patented thermal
transfer sensor and a patented laminar flow shunt assembly
that are used in the analog HFM-300 series flow instrumentation.
Each of these parts were improved over the standard
parts by examining the physics behind the nonlinearities in
the common thermal sensor and flow shunt design and
altering the operation and construction of these to remove
the primary sources of error.
The major source of non-linearity's for a laminar flow element
is a result of pressure drops due to a fluid entering or
exiting from a flow channel. The 300 series laminar flow
element is designed such that the pressure drops that are
measured occur in an annular region around the flow shunt
after the entrance effects and before the exit effects. This
greatly improves the linearity of the flow divider and minimizes
the large changes in linearity that typically occur when
the specific gravity of the flowing medium changes.
The typical errors in thermal sensors are due to the use of
a difference in the voltage in the heating circuit between the
upstream and downstream heater coil. The 300 series thermal
sensor controls the heated coils to a - (cont)