Clamp-on Ultrasonic Flow Meter

A clamp-on ultrasonic flow meter measures liquid volumetric flow by sound transit-time difference between an upstream-facing transducer and a downstream-facing transducer, both clamped to the outside of the host pipe with no pipe-cutting or shutdown. The on-board firmware sends ultrasonic pulses upstream and downstream alternately and computes the transit-time difference; flow velocity is proportional to that difference, with the time-difference signal resolved to 40 ps in the measurement circuit. Multiplying by pipe cross-sectional area returns volumetric flow. The UFM clamp-on covers DN15 to DN6000 host-pipe range via three transducer pairs (S / M / L) and reads bi-directional flow with reverse-direction detection.

The clamp-on supports steel, stainless steel, ductile iron, cast iron, copper, PVC, PE, HDPE, GRP, and concrete-lined pipe across the DN15 to DN6000 range. Pipe diameter range is divided by transducer-pair size: S transducer covers DN15 to DN100, M transducer covers DN50 to DN700, L transducer covers DN300 to DN6000. Cement-lined or scale-coated pipes may need acoustic-coupling treatment before transducer mounting; the engineering team confirms host-pipe compatibility at quote stage based on pipe material, wall thickness, and inner-surface condition. Particulate tolerance is up to 10 000 ppm suspended solids; for slurry above this threshold, go to the LEA polyurethane-lined slurry model.

Four mounting modes cover the full installation-condition range. V mode is the standard for standard host pipes; sound bounces once off the opposite pipe wall before reaching the receiving transducer; transducer spacing follows the spacing table per DN. Z mode is for large-bore service from DN100 to DN6000; sound passes through the pipe in single transit from one transducer face to the other, with transducer pair mounted on opposite sides of the pipe and typically 200 mm spacing. N mode is multi-reflection for adverse signal quality (degraded host-pipe surface, scaled inner wall); wider spacing, multiple bounces stretch the signal path for cleaner reception. W mode is the small-bore version for pipes below DN50; close-coupled transducer pair with multi-bounce path through the small pipe diameter. Specify the mounting mode at quote stage; the engineering team confirms based on pipe size, material, and operating conditions.

The installation procedure is fully non-invasive. The contractor identifies the longest available straight pipe run satisfying the 10D upstream / 5D downstream / 30D after pump straight-pipe rule, cleans the host-pipe outer surface, applies ultrasonic coupling gel between transducer face and pipe wall, and secures the transducer pair with stainless mounting straps at the specified spacing. The transmitter is wall-mounted near the transducer pair with SEYV75-2 sensor cable up to 500 m sensor-to-converter. Total field-install time is typically 1 to 3 hours per meter and does not require shutting down the upstream / downstream process service. Lead time for the meter itself stays 5 to 7 business days from the factory; field-install time is the buyer’s contractor scope.

Single-channel is the standard and suffices for HVAC sub-measurement, district-heating primary, data-center liquid cooling, and most utility-grade industrial service across DN15 to DN1000. Multi-channel makes sense in three patterns. First, large-bore custody-grade service above DN1000 where multiple acoustic paths cancel velocity-profile asymmetry for tighter accuracy. Second, irregular flow-profile service downstream of incomplete straight-pipe runs where averaging across multiple paths recovers reading stability. Third, redundancy for safety-instrumented function (SIF) or high-availability measurement where channel-pair failover is a procurement requirement. Specify single / dual / triple / five-channel at order; the engineering team confirms based on the bore, accuracy target, and any audit-trail requirements.

Three signal-output options cover the integration patterns. 4-20 mA analogue output (two channels standard) carries flow rate and totalizer into BMS / SCADA loop modules with 0.1 % output accuracy. RS-485 Modbus RTU exposes the totalizer register, instantaneous flow, alarm status, transducer-status diagnostics, and per-channel data over serial; fits LabVIEW, Python pymodbus, building-automation systems (BACnet via gateway), and SCADA Modbus polling. CAN bus is supported for industrial control networks. Pulse output (1-9999 Hz OCT) handles totalizer counting into PLC counter inputs. RS-232 is available for service-laptop direct connection during commissioning. HART is a factory option for HART-multiplexer rollouts where field-instrument digital overlay is already deployed.

Standard lead time is 5 to 7 business days from order confirmation, factory direct, including the transducer pair, coupling gel kit, and stainless mounting straps. The meter ships with an ISO 9001 calibration certificate listing the serial number, calibrated bore range, transducer pair size, and tested velocity range. EMC compliance to the EU Electromagnetic Compatibility Directive 2014/30/EU (Annex II) ships standard. IP65 is the standard ingress-protection rating on the fixed-mount transmitter housing; outdoor / submersible versions are factory-custom build at order. Hazardous-area Ex d certification is available as factory custom build but is not the standard option; Ex certification is buyer-arranged with the local notified body.