Compressed Air Turbine Flow Meter
Audit Standard Sub-Metering on Plant Air
Accuracy of ±0.5% of rate
Pipe DN25 to DN300
Turndown 1:30 for off-shift drift
- 3.6 V lithium battery option, 5-year typical service life
- 4G GPRS output for off-grid AMR endpoints
- Aluminium / 304 / 316L body for cost or chemistry service
LWGQ for compressed-air sub-measurement, ISO 50001 audit, tenant billing on shared compressors, and off-shift leak detection across DN25–DN300. Integrated flow conditioner + rotor + magnetic pickup; built-in T+P compensation outputs corrected Nm³/h on 4-20 mA. Turbine sits below DN300 where 1:30 turndown captures off-shift drift and 3.6 V lithium AMR removes SCADA wiring (LUGB vortex covers DN300+ headers). Aluminium body for tenant sub-meters; 304/316L for chemical compressor halls.
Benefits
- Audit standard ±0.5 % rate: factory K-factor for ISO 50001 baseline and ISO 11011 assessment.
- 1:30 turndown: trickle flow 1:15 vortex misses; where leak audits find savings.
- 3.6 V lithium AMR: ~0.3 mA standby, ~5-year service life on remote sub-meters.
- 4G GPRS output: streams to plant EMS/tenant-billing with no SCADA cabinet.
- Pre-pay controller option: retail tenant measurement where air is sold by Nm³.
- Dual hazardous-area: Ex d II CT6 Gb + Ex ia II CT6 Ga for compressor halls and classified zones.
- Lead time 5–7 business days from the factory.
Typical applications
Four sub-measurement applications where turbine wins on turndown, battery AMR, and accuracy.
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ISO 50001 plant-air energy audit
ISO 50001 plant-air audit: branch consumption, idle-drift, recoverable-leak baseline. 1:30 turndown reads trickle 1:15 vortex misses; logger preserves the audit trail.
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Tenant sub-measurement on shared compressor halls
Industrial parks on tenant feeds for cost allocation. Pre-pay controller feeds retail billing per Nm³; 3.6 V battery removes SCADA wiring.
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Leak detection on idle and off-shift drift
Branch-line returns track off-shift drift; trickle flow that signals leaks. 1:30 turndown catches what compressors hide; 4G streams night/weekend baseline.
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Plant-utility branch flow measurement for cost allocation
Multi-department sites allocate air cost across production, packaging, maintenance, utilities. Aluminium body cost-optimizes rollouts; RS-485 Modbus on EMS bus.
Specifications
| Measurement principle | Velocity-type turbine with magnetic-pickup pulse output |
|---|---|
| Pipe size range | DN25 – DN300 (1″ – 12″) standard, DN350 – DN400 special build |
| Accuracy | ±0.5 % of rate (billing-grade tenant) / ±1.0 % of rate (departmental) / ±1.5 % of rate (audit screening) |
| Turndown | 1:10 to 1:30 (depending on G-class flow rating selection) |
| Working pressure | 1.6 / 2.5 / 4.0 / 6.3 / 10 MPa metric, ANSI 150 LB / 300 LB / 600 LB |
| Medium | Dry compressed air (post-dryer, oil-removed); see FAQ for wet-air OOB redirect |
| Medium temperature | −25 to +80 °C |
| Ambient range | −20 to +65 °C, 5 % to 90 % RH non-condensing, 86 to 106 kPa atmospheric |
| Body material | Aluminium alloy (cost-optimized tenant sub-meter), 304, 316L (chemical-plant compressor halls) |
| Sensor material | 304 / 316L / titanium alloy |
| Compensation | Temperature, pressure, or none (T+P standard for Nm³/h normalized output) |
| Output signals | Pulse 3-wire, 4-20 mA 2-wire / 3-wire, RS-485 Modbus RTU, HART, GPRS / 4G IoT, pre-pay controller (factory option) |
| Power supply | 24 V DC standard, 3.6 V lithium battery (~0.3 mA standby, 5-year typical service life) |
| Display | Instantaneous flow, cumulative volume, temperature, pressure on integrated LCD |
| Data logging | Daily log + timed-interval log (audit-trail retrievable) |
| Transmission distance | Pulse 3-wire ≤ 300 m, 4-20 mA 2-wire ≤ 1500 m (load ≤ 500 Ω), RS-485 / HART ≤ 1200 m |
| Ingress protection | IP65 / IP66 |
| Hazardous area | Ex d II CT6 Gb (flameproof) + Ex ia II CT6 Ga (intrinsically safe) |
| Approvals | EMC 2014/30/EU (Annex II), ISO 9001 calibration certificate with each meter |
Installation
Five install rules for LWGQ on dry compressed-air service.
- Place the meter downstream of the dryer and oil-removal filter The LWGQ requires clean dry air. Install on the post-dryer leg with an oil-coalescing filter upstream when the compressor lubrication is mineral oil. Wet-air placement upstream of the dryer voids the K-factor calibration.
- Horizontal install with the housing arrow aligned to flow The LWGQ supports horizontal install only; vertical mount is not permitted. The flow direction arrow on the housing must match line flow.
- Maintain ≥ 3 DN upstream and ≥ 1 DN downstream straight pipe The integrated upstream flow conditioner accepts the 3 DN minimum upstream of any elbow, valve, or pressure regulator, and 1 DN minimum downstream. Tighter installs distort the velocity profile.
- Install isolation valves and a bypass loop on shared-feed lines Upstream and downstream isolation valves let the meter come out of service without shutting down the tenant or department. The bypass loop stays closed during normal service and opens only during maintenance windows.
- Earth-ground the meter housing on a separate ground line External-power builds require reliable earth grounding, but the meter ground must NOT share with the high-voltage system. Battery-powered builds are inherently isolated; mains-powered builds must keep grounding clean to avoid pickup interference on the pulse signal.
Frequently asked questions
What is a compressed air turbine flow meter and how does it work?+
A compressed air turbine flow meter measures volumetric air flow through a free-spinning rotor mounted in the pipe bore. Dry compressed air enters an integrated upstream flow conditioner that straightens and accelerates the profile, the rotor blades intercept the conditioned flow at a fixed angle, and a magnetic pickup reads pulses proportional to volumetric flow through the calibrated K-factor. Built-in temperature and pressure compensation outputs corrected normal-cubic-metre flow (Nm³/h) directly on the 4-20 mA loop for sub-measurement and energy-audit applications.
When does turbine beat vortex for compressed air sub-measurement?+
Turbine is the better pick for ISO 50001 plant-air audit, tenant sub-measurement on shared compressor systems, and leak detection on idle / off-shift drift. The 1:30 turndown captures the trickle flow that 1:15 vortex misses, and the 3.6 V lithium battery option supports off-grid AMR endpoints with a 5-year service life. Vortex (LUGB) stays the better choice for large-bore main-distribution measurement above DN300 where no moving parts and zero pressure drop matter more than turndown depth.
How does the meter support ISO 50001 plant-air audit?+
The integrated daily-and-interval data logger preserves an audit trail showing instantaneous flow, cumulative volume, temperature, and pressure on each interval. The factory K-factor calibration certificate with each meter provides traceability for ISO 50001 energy-baseline reporting. The 1:30 turndown captures the small idle-drift flows that compressed-air audits target as recoverable savings, and the 4G GPRS output streams data directly to plant energy-management systems without requiring SCADA cabinet integration.
What pipe sizes and accuracy classes support tenant sub-measurement?+
DN25 to DN300 covers most plant-air branch lines and tenant feeds in industrial parks and shared compressor halls. The ±0.5 % of rate accuracy class supports billing-grade tenant cost allocation; ±1.0 % of rate is acceptable for departmental cost-tracking; and ±1.5 % of rate is the audit-screening grade for early leak-detection scoping. Pre-pay controller output is available for retail tenant-side measurement where compressed air is sold by Nm³.
What is the dry-air requirement and what fluids fall outside the range?+
The LWGQ requires clean dry compressed air after the dryer and oil-removal filter. Wet compressed air (pre-dryer with carry-over condensate), 2-phase service, and steam are outside the range; carry-over liquid disturbs the rotor and biases the K-factor. For wet compressed air on the upstream side of the dryer, choose vortex (LUGB) or thermal-mass (TMF) instead. For very low flow below 0.5 m/s velocity (deep idle drift on small-bore lines), thermal-mass (TMF) with a 0.1 Nm/s low-flow detection is the better choice.
Is the battery option suitable for off-grid AMR endpoints?+
Yes; the 3.6 V lithium battery option with about 0.3 mA standby current supports a typical 5-year service life on remote sub-meter installations without permanent power. The 4G GPRS output streams readings directly to plant energy-management or tenant-billing systems without local SCADA. The integral display reads instantaneous flow, cumulative volume, temperature, and pressure on the LCD with a daily and timed-interval logging file preserved on-board for audit retrieval.
What is the lead time and what certifications ship standard?+
Standard lead time is 5 to 7 business days from order confirmation, factory direct. Each meter ships with an ISO 9001 calibration certificate listing the K-factor, calibrated DN, and tested flow range for each meter. Hazardous-area certification options are Ex d II CT6 Gb (flameproof, Zone 1) for petrochemical-adjacent compressor halls, plus Ex ia II CT6 Ga (intrinsically safe) for classified areas where flameproof housing rework is impractical. EMC compliance to the EU Electromagnetic Compatibility Directive 2014/30/EU (Annex II) ships standard with IP65 or IP66 ingress selectable.
Need help sizing a compressed-air sub-meter rollout?
Send line size, application, pressure, battery vs mains. Engineering replies in 1 day; lead time 5–7 business days from factory.