HFM-D-300/HFC-D-302 - Teledyne Hastings Instruments - #1

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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)