Bürkert 20087874 (Type 8745) is a high-performance Mass Flow Controller (MFC) and Mass Flow Meter (MFM) designed for controlling the mass flow of large gas quantities. Configured for air with a nominal flow rate of 90 Nm³/h and a G 3/4" internal thread connection, this specific model utilizes PROFINET communication for seamless industrial integration. The thermal inline sensor, located directly in the main gas stream, achieves very fast response times with minimal pressure loss. As an actuator, a Bürkert direct-acting proportional valve guarantees high response sensitivity.

Key features of the Type 8745 family include:

• Nominal flow range from 20 lN/min to 2500 lN/min (re. nitrogen)
• High accuracy and repeatability
• Communication via standard signals or Industrial Ethernet (PROFINET, EtherCAT, EtherNet/IP, Modbus TCP)
• Electromagnetic and electromotoric valve actuation available
• Easy device exchange due to configuration memory

General Technical Data

Property	Description
Housing Material	PC (polycarbonate)
Base Block Material	Aluminium or stainless steel 1.4404/316L
Seal Material	FKM or EPDM (depending on gas)
Operating Voltage	24 V DC (±10% voltage tolerance, ±2% residual ripple)
Medium Temperature	-10 °C to +70 °C (-10 °C to +60 °C with oxygen)
Ambient Temperature	-10 °C to +50 °C
Degree of Protection	IP20
Turndown Ratio	1:50

Actuator Variants

Type 8745 can be configured with different proportional valves depending on the application requirements.

Variant with Electromagnetic Proportional Valve

The MFC variant uses direct-acting proportional valves of the 287x series. These electromagnetic proportional valves are normally closed and stand for highest measuring accuracy and repeatability with settling times of a few hundred milliseconds.

• Operating Pressure: Max. 25 bar (depends on medium and nominal valve size)
• Measuring Accuracy: ±1.5% MV, ±0.3% FS (under calibration conditions)
• Settling Time (t95): < 500 ms
• Power Consumption: Max. 12.5 to 31.5 W (as MFC)

Variant with Electromotive Proportional Valve

Type 8745 with electromotive proportional valve is especially suitable for applications with high inlet pressures of up to 22 bar or high flow rates at a low pressure drop. The motor’s power consumption to hold a specific opening position is nearly zero, drastically reducing energy consumption.

• Operating Pressure: Max. 25 bar (MFM max. 22 bar)
• Measuring Accuracy: ± 2% MV, ± 0.5% FS (under calibration conditions)
• Settling Time (t95): < 5 s
• Power Consumption: Max. 12 W (as MFC)

Measurement Principle

This sensor works as a hot-film anemometer in the CTA (Constant Temperature Anemometer) operational mode. Two resistors with a precisely specified temperature coefficient located directly in the media flow and three further resistors are connected to form a measuring bridge. The heating current required to maintain a fixed excess temperature is a measure of the heat dissipation and represents the primary measured variable.

Communication and Connections

The 20087874 model features PROFINET communication via Industrial Ethernet. All Industrial Ethernet-based devices (except for the EtherCAT® protocol) from software version A.13.00.00 onwards have an integrated web server accessible via the device's IP address.

Industrial Ethernet Terminal Strip (3-pin):

Pin	Assignment
1	FE (functional earth)
2	DGND
3	24 V

Approvals and Conformities

Depending on the specific configuration, Type 8745 devices can meet various industry standards:

• North America: Optional UL Listed for the USA and Canada (UL 61010-1).
• Foods and Beverages/Hygiene: FDA compliance, USP Class VI, and EC Regulation 1935/2004 available for specific wetted materials.
• Oxygen: Optional suitability for use with gaseous oxygen.

Product Accessories

Bürkert Communicator Software

The Bürkert Communicator is the most important software component of the EDIP (Efficient Device Integration Platform). It simplifies the configuration, parametrisation, and diagnosis of devices. The connection to the PC is established with a USB-büS interface set.

Configuration Management

If a device needs to be replaced, the memory card can be removed from the defective device and inserted into the new device. This transfers all data to the new device, provided both devices have the same article number.

Safety Information

The device contains electronic components that are susceptible to the effects of electrostatic discharging (ESD). Do not touch electronic components when the supply voltage is connected. Touching live parts can result in severe electric shock. Before working on the device or system, switch off the power supply and secure it against reactivation.