SPIRAX SARCO · FLOW MEASUREMENT
Spirax Sarco VLM30 In-line Vortex Flowmeter for Steam, Liquid & Gas Flow Measurement
Spirax Sarco VLM30 in-line vortex flowmeter for steam, liquid & gas measurement. DN15-DN300 sizes, PN16-PN100 ratings. Buy from PC Engineering India.

Overview
The Spirax Sarco VLM30 is an in-line vortex flowmeter designed for accurate measurement of liquid, gas, and steam flow in industrial applications. The meter operates on the vortex shedding principle — a bluff body within the flow path generates vortices at a frequency directly proportional to flow velocity. This proven physical relationship ensures reliable and repeatable flow measurement across varying process conditions.
The VLM30 utilises three primary sensing elements: a vortex shedding velocity sensor, an internal RTD temperature sensor (or external temperature transmitter), and an external pressure transducer (supplied separately). Using local velocity data combined with fluid type, pipe size, and Reynolds number, the flowmeter calculates average pipe velocity and volumetric flowrate. Two variants are available: the VLM30-S for saturated steam, liquid, and gas applications with optional binary output, and the VLM30-E with integrated flow computer, energy calculation, and connectivity for external transmitters.
The VLM30 is suitable for any gas, liquid, or steam compatible with stainless steel wetted parts. It is not recommended for multi-phase fluids. The unit complies with EMC Directive EN 61326-1:2013, PED Directive EN 12516-2:2014, and holds CRN approval for Canada.
Key Features
- Measures flow of saturated steam, superheated steam, liquids, and gases
- Vortex shedding principle ensures no moving parts and minimal maintenance
- VLM30-S: graphical display, optional binary output, integrated temperature measurement
- VLM30-E: integrated flow computer with energy calculation and external transmitter inputs
- HART 7 protocol and Modbus RTU communication options
- IP66/IP67 and NEMA 4x enclosure rating for harsh environments
- Stainless steel 316Ti/316L wetted parts for broad chemical compatibility
- Available in flanged and wafer-type configurations
Specifications
| Parameter | Value |
|---|---|
| Sizes (Flanged) | DN15 to DN300 / ½" to 12" |
| Sizes (Wafer) | DN25 to DN150 / 1" to 6" |
| Flange Standards | EN 1092-1 PN16, PN40, PN63, PN100; ASME B16.5 Class 150, 300, 600 |
| Wafer Pressure Rating | PN63 / ASME Class 300 (PN100 / Class 600 on request) |
| Meter Tube Material | Stainless steel 1.4571 (AISI 316Ti) / AISI 316L / CF8C / C3FM |
| Sensor Material | Stainless steel 1.4571 (AISI 316Ti) |
| Sensor Gasket Options | PTFE O-ring / Kalrez 6375 / Graphite (high-temp) |
| Temperature Range | -60°C to 350°C (-76°F to 662°F) |
| Supply Voltage (HART) | 12 to 24 Vdc |
| Supply Voltage (Modbus) | 9 to 30 Vdc |
| Power Consumption | < 1 W |
| Output Signal | 4–20 mA, HART digital, Modbus RTU (RS485) |
| Enclosure Rating | IP66, IP67, NEMA 4x (EN 60529) |
| Cable Glands | M20 x 1.5 or ½" NPT (2 places) |
| Compliance | EMC EN 61326-1:2013, PED EN 12516-2:2014, CRN 0F24350.5C |
Applications
The Spirax Sarco VLM30 vortex flowmeter is widely used across process industries requiring accurate steam, gas, or liquid flow measurement:
- Steam flow monitoring and energy management in power plants and utilities - Process steam metering in pharmaceutical, food & beverage, and chemical manufacturing - Compressed air and industrial gas flow measurement - Thermal oil and hot water flow in heating systems - Boiler house efficiency monitoring and steam cost allocation
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