BURKERT Type 8745 (SKU 20077380) is a mass flow controller (MFC) / mass flow meter (MFM) suitable for controlling the mass flow of large gas quantities. It can be configured as an MFM or MFC according to demand. The thermal inline sensor located directly in the main gas stream achieves very fast response times with minimal pressure loss. As the actuator, a Bürkert direct-acting proportional valve guarantees high response sensitivity. This specific model is configured for CO2 with a capacity of 90 kg/h, utilizing PROFINET communication and FKM seals.

General Technical Data

Feature	Description
Seal Material	FKM or EPDM (depending on gas)
Housing Material	PC (polycarbonate)
Base Block Material	Aluminium or stainless steel 1.4404/316L
Wetted Parts (Sensor)	Stainless steel 1.4404/316L, Al2O3, PPS GF40, epoxy resin, silicon, silicon nitride
Operating Voltage	24 V DC (±10% voltage tolerance, ±2% residual ripple)
Operating Medium	Neutral, pure gases (others on request)
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
Installation Position	Horizontal or vertical

Note on Temperature

When using an electromotive proportional valve, the minimum medium temperature is 0 °C.

Actuator Variants

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 (response times) of a few hundred milliseconds (< 500 ms).

• Nominal flow range (QN): MFC: 20...1500 lN/min (N2); MFM: ≤ 2500 lN/min (N2)
• Operating pressure: Max. 25 bar (depends on medium and nominal valve size)
• Measuring accuracy: ±1.5% MV, ±0.3% FS
• Turndown ratio: 1:50
• Power consumption: Max. 4 W (as MFM); Max. 12.5...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, which can reduce the energy consumption of a plant dramatically. Without electrical power, the valve remains in its current position.

• 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
• Settling time (t95): < 5 s
• Power consumption: Max. 4 W (as MFM); Max. 12 W (as MFC)

Approvals and Conformities

• North America (USA/Canada): Optional UL Listed (UL 61010-1, CAN/CSA-C22.2 No. 61010-1).
• Foods and Beverages/Hygiene: FDA (Code of Federal Regulations), USP (United States Pharmacopeial Convention) biocompatibility, EC Regulation 1935/2004.
• Oxygen: Optional suitability for gaseous oxygen.

Performance Specifications

Nominal Flow Rate of Typical Gases

All values refer to 1013.25 mbar abs and 273.15 K (0 °C).

Gas	Min. QN [l/min]	Max. QN [l/min]
Acetylene	20	320 (from 65 l/min with air calibration)
Ammonia	8	1000
Argon	20	1600
Carbon dioxide	20	800 (1000 for MFM)
Air	20	2500
Methane	20	1200
Propane	20	200
Oxygen	20	2500
Nitrogen	20	2500

MFM Pressure Loss Diagram

The diagram shows an example of the pressure loss curves with air flowing through. To determine the pressure loss of other gases, the corresponding air equivalent must first be calculated.

Derating Diagram for Electromotive Variants

Product Operation

Measurement Principle

This sensor works as a hot-film anemometer in the CTA operational mode (Constant Temperature Anemometer). 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 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.

• 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.

Electrostatically sensitive components

The device contains electronic components that are susceptible to the effects of electrostatic discharging (ESD). Meet the requirements specified by EN 61340-5-1 to minimize or avoid the possibility of damage.