The Burkert Type 8745 is a high-performance mass flow controller (MFC) and mass flow meter (MFM) designed to control the mass flow of large gas quantities. It can be configured as an MFM or MFC according to demand, with the option to store up to four calibration curves in the device. The thermal inline sensor, located directly in the main gas stream, achieves very fast response times with minimal pressure loss. As an actuator, a Burkert direct-acting proportional valve guarantees high response sensitivity. The Type 8745 is available with either an electromagnetic or electromotive proportional valve, and supports Analogue, Industrial Ethernet, and Modbus RTU communication interfaces.

General Technical Data

Property	Value
Material
Seal	FKM or EPDM (depending on gas)
Housing	PC (polycarbonate)
Base block	Aluminium or stainless steel 1.4404/316L
Wetted parts (sensor)	Stainless steel 1.4404/316L, Al2O3, PPS GF40, epoxy resin, silicon, silicon nitride
Electrical data
Operating voltage	24 V DC
Residual ripple	±2%
Voltage tolerance	±10%
Medium data
Operating medium	Neutral, pure gases (others on request)
Calibration medium	Operating medium or air
Medium temperature	-10 °C to +70 °C (-10 °C to +60 °C with oxygen)
Environment and installation
Installation position	Horizontal or vertical
Degree of protection	IP20

Variant with Electromagnetic Proportional Valve

Type 8745 can be configured as MFM or MFC as required. The MFC variant uses direct-acting proportional valves of the 287x series (including Type 2836). These electromagnetic proportional valves are normally closed and stand for highest measuring accuracy and repeatability with settling times resp. response times of a few hundred milliseconds.

Performance data	Value
Nominal flow range (QN)	MFC: 20...1500 lN/min (N2) MFM: ≤ 2500 lN/min (N2)
Operating pressure	MFM: max. 25 bar MFC: max. 25 bar (depends on medium and nominal valve size)
Measuring accuracy	±1.5% MV, ±0.3% FS
Repeatability	±0.1% FS
Turndown ratio	1:50
Settling time (MFC) / Response time (MFM)	< 500 ms

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. Without electrical power, the valve remains in its current position.

Performance data	Value
Nominal flow range (QN)	20...2500 lN/min (N2)
Operating pressure	MFM: max. 22 bar MFC: depends on medium and nominal valve size
Measuring accuracy	± 2% MV, ± 0.5% FS
Repeatability	± 0.5% FS
Turndown ratio	1:50
Settling time (MFC) / Response time (MFM)	< 5 s

Approvals and Conformities

• North America (USA/Canada): Optional UL Listed for the USA and Canada according to UL 61010-1 and CAN/CSA-C22.2 No. 61010-1.
• Foods and Beverages/Hygiene: FDA (Code of Federal Regulations), USP (United States Pharmacopeial Convention), and EC Regulation 1935/2004 compliance available depending on variable codes.
• Oxygen: Optional suitability for use with gaseous oxygen.

Dimensions

MFC with valve Type 2836

Variant with base block 00 or A1 for small nominal flow rates.

Note

Dimensions in mm.

Product Operation

Measurement Principle

This sensor works as a hot-film anemometer in the so-called CTA operational mode (Constant Temperature Anemometer). 2 resistors with a precisely specified temperature coefficient located directly in the media flow and 3 further resistors are connected to form a measuring bridge. The first resistor in the gas flow measures the fluid temperature, while the second, low value resistor is always heated just enough to keep it at a fixed, specified excess temperature with respect to the fluid temperature. The heating current required for this is a measure of the heat dissipation and represents the primary measured variable.

Safety Information

Electric shock due to electrical components

Touching live parts can result in severe electric shock. This can lead to serious personal injury or death.

• Before working on the device or system, switch off the power supply. Secure it against reactivation.
• Observe any applicable accident prevention and safety regulations for electrical devices.

Medium under pressure

Medium under pressure can seriously injure people. In the event of overpressure or pressure surges, the device or lines can burst. Pneumatic lines that are defective or not securely fastened can come loose and swing around.

• Before working on the device or system, switch off the pressure. Vent or empty the lines.
• Adhere to the permitted pressure ranges of the medium.

Hot surfaces and fire hazard

The surface of the device can become hot with fast-switching actuators or with hot media.

• Wear suitable protective gloves.
• Keep highly flammable substances and media away from the device.