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The Flow Meter: 3925-0160

Our flow meter operates on the thermodynamic principle. The device utilizes the linear relationship between flow velocity and transported energy. Two thermal resistance elements are mounted on a thin stainless steel tube. A portion of the gas flow passes through this bypass sensor within the flow meter and is heated by two constant-power heaters. Due to the heat transfer, the two temperatures diverge. The temperature difference is directly proportional to the mass flow.

Flow Meter in Detail: Here Are the Benefits

In industry, flow measurement is frequently used for product testing. A flow meter can be used to test pipe assemblies (e.g., exhaust systems), valves, fittings, and many other products.

Direct measurement of mass flow represents a highly accurate measurement technique. Combined with a wide selection of possible measuring ranges and a broad turndown ratio of 1:50, our flow meters are ideally suited for a diverse range of applications.

Various methods can be employed for mass flow measurement. Our device features a thermal mass flow meter which, unlike volumetric flow meters, requires no additional temperature and pressure sensors for accurate mass flow measurement. Consequently, the installation of our flow meters is remarkably simple, facilitating the quality inspection of your products.

How the Flow Meter Works

The automation and optimization of workstations must also be implemented in quality assurance. For the inspection of serial parts, it is therefore essential that the flow meter integrates seamlessly into automated manufacturing processes. The microprocessor-controlled 3925-0160 flow meter meets the following requirements:

Automated testing sequence
Storage of test programs
Contamination-free testing
Reproducible measurement results
Short cycle times combined with high precision
Unambiguous measurement results
Indication of measured values in ml/min, etc.
Variable test pressures and test times for optimal adaptation to the manufacturing of diverse components
Ease of operation through guided user interfaces
Service-friendly modular design

Operating Principle of the Flow Meter

A high-precision thermal mass flow meter with high sensitivity serves as the transducer for the flow meter. It consists of a measuring tube and an interchangeable bypass that determines the measuring range. The measuring tube and bypass are designed to ensure laminar flow.

The airflow through the sensor is split into a main flow and a secondary flow. A precision laminar flow element is utilized for this purpose. The secondary flow passes through a bypass sensor.

Two thermal resistance elements are mounted on a thin stainless steel tube. The gas flow is heated by two constant-power heaters. Due to heat transfer, the two temperatures drift apart. The temperature difference is directly proportional to the mass flow. Thanks to the precise split between the bypass and main flow, the sensor signal is also proportional to the total mass flow.

Operation

Operating our flow meter is exceptionally straightforward. Test parameters are programmed via a menu-guided interface, requiring no prior specialized knowledge. The required parameters for the test program are prompted and stored in the program memory. Data security is ensured via a write-protection switch. When the device is secured, parameters can be read but cannot be modified.

Higher-level control systems can communicate with the flow meter via various interfaces. A standard serial interface is provided for connecting to computer systems or a printer. The digital interface for communication with machine controllers is also included as standard. Furthermore, the flow meters can be optionally equipped with a ProfiBus or ProfiNet interface.

Pneumatic Section Design

Microprocessor-controlled electronic pressure regulation for filling and test pressure
Thermal mass flow meter, pressure rating PN100
Function monitoring

Electronic Section Design

Modular processor system
Data backup in battery-backed RAM
Alphanumeric keyboard
5-inch color display
Write-protection switch against unauthorized parameter modification
Plain text error messages
Menu-guided programming and calibration
Various interfaces for communication with higher-level control systems

Microprocessor:

Modular system

Program memory:

Battery-backed RAM

Transducer:

Mass Flow Meter (MFM) Pressure Rating: PN100

Measured value display:

5" color LCD display, 320x240 pixels

Keypad:

Alphanumeric input field

Measuring range:

0 ... 50; 100; 200; 500 ml/min, 0 ... 1000; 2000 ml/min, 0 ... 5; 10; 20; 50; 100 l/min, other measurement ranges available upon request

Measurement resolution:

via high-resolution sigma-delta A/D converters—1 converter per measurement channel

Measured values:

In ml/min, l/min, and m³/h

Test programs:

Filling and test pressure:

Electric pressure adjustment with tolerance monitoring—1.0 ... 0 bar/g; 0.1 ... 1.0 bar/g; 0.15 ... 2.5 bar/g; 0.2 ... 6.0 bar/g; 0.5 ... 10.0 bar/g; 0.5 ... 12 bar/g; other pressure ranges available upon request

Test parameters:

Filling pressure ... bar Test pressure ... bar Filling time 0.1 ... 999.9 s Stabilization time 0.1 ... 999.9 s Measurement time 0.1 ... 999.9 s Lower tolerance from ... Upper tolerance from ... Series error from ... "Non-conforming" parts

Write protection:

via key switch

Status display:

Lower Tolerance (UT) OK Upper Tolerance (OT) "Error"

Measurement data memory:

Up to 8,000 test results (internal battery-backed RAM); larger data sets via USB storage devices that can be connected to the front panel

Interfaces:

Control inputs: 24 V; 500 mA 1-bit automatic 1-bit machine ready 1-bit start 1-bit fill 8-bit program selection 1-bit cancel

Enclosure:

19" rack-mount unit, 3 HU

Dimensions:

165 x 590 x 420 mm (H x W x D)

Power supply:

115/230 V ±10 %, 50 ... 60 Hz

Power consumption:

approx. 100 VA

Air supply:

Test air: 1.5 bar > test pressure; control air: max. 6 bar, dry, oil-free, and filtered

Pneumatic connections:

Supply air connection G¼", test medium connection G¼" (optional), test connection G¼", venting via silencer G¼"

Weight:

approx. 15 kg

Standard accessories:

Power cord, approx. 2.5 m long; Key for the write-protect switch; User manual

Order no.:

Flow meter 3925-0160

Downloads

Data Sheet

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