Sierra Instruments' Model 640S Compressed Air Flow Meter facilitates compressor audits and enhances plant management and control strategies. Virtually immune to variations in temperature and pressure, the meter provides an accurate mass flow measurement under varying loads. Its rugged, no-moving parts design is also ideal for the high-vibration environment found in most compressor applications.

Hot-tap mounting, a variety of self-diagnostic and field-adjustment features, as well as the ability to confirm or "field-validate" the meter's calibration and measurement accuracy ensures traceability in compressor audits. The Model 640S also offers outstanding low-flow sensitivity, fast response, and low maintenance requirements for point-of-use measurement, cost-allocation and system diagnostics applications.

The microprocessor-based transmitter integrates the functions of flow measurement, flow-range adjustment, meter validation and diagnostics in a compact, explosion-proof housing. Mass flow rate and totalized flow, as well as other configuration variables, are displayed on the meter's 2 x 12 back-lit LCD panel. The programmable transmitter is easily configured via an RS-232 com port and Sierra's Smart Interface PC-based software; or via the display and membrane switches on the front panel of the device.

The Model 640S permits field-configuration of the following parameters: flow range, totalizer, alarm settings, time response, zero flow cut-off and a calibration correction factor to compensate for flow profile variations or specific application conditions. Smart Interface also furnishes a means to directly adjust the meter's calibration for a different gas composition or flow range.