VA 521

Compact In-line Flow Meter for Compressed Air and Gases — VA 521

Спецификация VA 521

Available on request
Delivery across Russia
Order phone: +7(800)777-18-50

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Description

The new VA 521 flow meter combines modern digital interfaces for connection to energy monitoring systems with a compact design. The VA 521 is used in cases where many devices (compressed air consumers) need to be included in the energy monitoring network.

Thanks to the built-in flow rectifier, no straight pipe sections are required before the flow meter.

Advantages

Compact design for installation in systems after the service unit
Interface configuration from the device display
Digital Modbus RTU interface
Analog output 4...20 mA for current flow
Galvanically isolated pulse output (counter).
Optional: M-Bus, Ethernet, PoE

Specifications
Overall Drawing
Applications

Characteristic	Value
Measurable parameters:	m³/h, l/min (1000 mbar, 20 °C) for compressed air or n.m³/h, n.l/min (1013 mbar, 0° C) for other gases
Units of measurement:	m³/h, m³/min, l/min, l/s, ft/min, cfm, m/s, kg/h, kg/min, g/s, lb/min, lb/h
Measurement principle:	Thermal mass flow meter
Measurement medium:	Air, gases
Types of gases (selectable via software or data loggers):	Air, nitrogen, argon, carbon dioxide, oxygen, etc.
Measurement range:	90 m³/h, 170 m³/h, 290 m³/h, 530 m³/h, 730 m³/h, 1195 m³/h
Accuracy: (FS = full scale)	± 1.5 % of reading ± 0.3 % FS On request: ± 1 % of reading ± 0.3 % FS or ± 6 % of reading ± 0.5 % FS
Measurable pressure:	0...16 bar, accuracy: 1 %
Operating temperature:	-30...80 °C
Operating pressure:	Up to 16 bar, optionally up to 40 bar
Digital interface:	RS 485 interface (Modbus RTU), optional: M-Bus, Ethernet or PoE
Analog output:	4...20 mA for m³/h or l/min
Pulse output:	1 pulse per m³ or l, galvanically isolated. Configuration is done via display. Can also be used as a signal relay.
Power supply:	18...36 V (DC), 5 W
Load:	< 500 Ohm
Housing material:	Polycarbonate (IP 65)
Measuring section material:	Aluminum, 316L
Connection thread:	From G 1/2“ to G 2“ or from 1/2“ to 2“ NPT
Installation position:	Any

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Compact Insertion Flow Meter for Compressed Air and Gases VA 521

Effective energy consumption management at an enterprise begins with accurate measurements. The VA 521 compressed air flow meter is a modern device for flow monitoring, specially designed for tasks where compactness and high accuracy without complex installation are important. The device combines an electronic measurement system, a display, and a built-in flow straightener, making it a unique tool in its segment.

This device is ideal for integration into systems, allowing monitoring of consumption on specific lines, detecting leaks, and optimizing the use of air and technical gases.

If you need to request additional technical documentation for the product or require consultation on selecting a configuration for your task, contact our specialists via the form on the website or by phone.

Key Features and Advantages of the VA 521 Flow Meter

The main difficulty when installing most measuring devices is the need for long straight sections of pipeline before and after the sensor. In dense factory layouts or inside compressor cabinets, providing free 10–15 pipe diameters is often impossible.

The VA 521 technical gas and air flow meter solves this problem. Thanks to the built-in flow straightener in the measuring section, the device does not require straight sections. This allows it to be installed immediately after the air preparation unit, filters, or shut-off valves without loss of measurement accuracy.

List of main advantages:

Compactness: Ideal for installation in tight spaces and distribution cabinets.
Interface versatility: Equipped with Modbus RTU (RS 485) for data transmission. Also features an analog output 4...20 mA and galvanically isolated pulse output.
Informative display: The screen shows current flow (m3/h, l/min), accumulated flow (m³, l, kg), and temperature. The display image can be rotated 180° if the device is installed upside down.
Replaceable sensor: The measuring unit is easily removable from the section for cleaning. This is critically important for systems where the air may contain oil impurities.

Along with this device, you may also be interested in the following similar instruments:

VA 500 Air and Gas Flow Meter with Digital Interface — immersion flow meter.
VA 520 Insertion Flow Meter for Gases and Compressed Air — negligible pressure loss.
Insertion Flow Meters — for flow control when stopping the technological process is impractical.

Operating Principle and Measurement Technologies of the VA 521 Compressed Air Flow Meter

The VA 521 belongs to the class of thermal mass flow meters. This measurement principle directly determines mass flow rather than volumetric flow. The operation is based on the calorimetric method. The sensor is heated to a certain temperature above the medium temperature. The passing gas flow cools the sensor. The current required to maintain the temperature difference is directly proportional to the mass of the passing gas.

Why this is important for industry:

Measurement principle and reference conditions
The device operates on the thermal mass principle, allowing flow measurement without additional pressure sensors. Flow readings are automatically converted to established reference conditions, which vary depending on the gas type:
- For compressed air: displayed in m3/h or l/min at 1000 mbar, 20˚C (according to ISO 1217 standard).
- For other gases: displayed in normal n.m3/h or n.l/min at 1000 mbar, 20˚C (can be changed in the device settings if necessary). [Note: If needed, reference conditions can be easily changed in the device settings].
This eliminates confusion in calculations and ensures correct consumption accounting regardless of parameter fluctuations.
High sensitivity: The device can detect even the smallest flows, making it an excellent tool for leak detection (pneumo-audit) during weekends or equipment downtime.

Application Areas: Where the VA 521 Insertion Flow Meter is Used

The device is designed for a wide range of tasks and is not limited to compressed air accounting only. The software allows adapting the device for use with various types of gases. Main usage options:

Compressed air accounting: Network balancing, cost distribution between workshops, compressor efficiency control.
Technical gases: Measurement of Nitrogen (N2), Argon (Ar), Oxygen (O2), Carbon Dioxide (CO2), and other gases.
Medicine and pharmaceuticals: Control of gas supply in clean rooms and hospital pipelines.
Food industry: Gas accounting during product packaging in modified gas atmospheres.

Technical Specifications and Properties

The key factor in choosing is the exact parameters. The VA 521 model is suitable for most industrial lines with diameters from 1/2" to 2" (DN 15 – DN 50).

Parameter	Value / Description
Measured medium	Compressed air, Nitrogen (N2), Argon (Ar), CO2, Oxygen (O2), etc.
Measurement principle	Calorimetric (thermal mass)
Accuracy (standard)	±1.5% of measured value ±0.3% of full scale (FS)
Accuracy (option)	±1.0% of measured value ± 0.3% of FS / ± 6 % of measured value ± 0.5 % FS
Operating pressure	up to 16 bar — standard; up to 40 bar — optional
Medium temperature	from -30 to 80 °C
Power supply	18...36 V (DC), 5 W
Output signals	analog 4...20 mA, pulse (galvanically isolated), Modbus-RTU (RS-485)
Enclosure protection class	IP 65 (dust tight, protection against water jets)
Enclosure material	Polycarbonate (impact resistant)
Section material	Aluminum, stainless steel 316L

Measurement Ranges (for compressed air)

Thread	Measuring section (DN)	Measurement range (up to)
G 1/2"	DN 15	90 m³/h
G 3/4"	DN 20	170 m³/h
G 1"	DN 25	290 m³/h
G 1 1/4"	DN 32	530 m³/h
G 1 1/2"	DN 40	730 m³/h
G 2"	DN 50	1195 m³/h

Note: For other gases, ranges may differ; details are provided in the user manual.

Where to Buy and How to Order a Compressed Air Flow Meter

The company «Izmerkon» offers original VA 521 series devices with full technical support. We will help you select the correct diameter and connection type for your tasks and requirements to avoid installation errors.

To place an order, submit an application on the website. Our specialists will provide current prices, delivery times, and all required certificates (the calibration certificate is supplied with the devices upon purchase).