BURKERT 20143453 Type 8741 mass flow controller (MFC) / mass flow meter (MFM) for gases is suitable for a variety of applications. This specific model is configured for Helium (He) with a nominal flow range of 60 Nl/min, featuring an aluminium body, EPDM seals, G 1/4" internal thread, and a 4-20 mA analogue output signal. The thermal MEMS sensor is located directly in the gas stream and therefore achieves very fast response times. As an actuator, a Bürkert direct-acting proportional valve guarantees high response sensitivity.

Key features of the Type 8741 series include:

• High accuracy in measurement and repeat accuracy
• Very fast response times
• Easy device exchange due to configuration memory
• Optional: USP Class VI, FDA, EC 1935 compliant

General Technical Data

Product Properties	Description
Material
Seal	EPDM (Ethylene-propylene-diene rubber)
Housing	PC (polycarbonate)
Base block	Aluminium
Wetted parts	Stainless steel 1.4310/302, 1.4113/434, 1.4305/303
Total weight	Approx. 500 g (aluminium base block)
Performance Data
Nominal flow range	60 Nl/min (He helium)
Operating pressure	Max. 25 bar
Measuring accuracy	±0.8% MV ±0.3% FS (under calibration conditions)
Repeatability	±0.1% FS
Turndown ratio	1:50
Settling time (t95)	<300 ms
Electrical Data
Operating voltage	24 V DC
Residual ripple	±2%
Voltage tolerance	±10%
Environment and Installation
Installation position	Horizontal or vertical
Ambient temperature	-10 °C...+50 °C
Degree of protection	IP20

Approvals and Conformities

Note

The approvals and conformities listed below must be stated when making enquiries. Not all available variants can be supplied with the below mentioned approvals or 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 options available.
• Oxygen: Optional suitability for use with gaseous oxygen.

Measurement Principle

The measured values are recorded in a secondary channel. A laminar flow element in the main channel creates a slight pressure drop. A part of the gas flow is thereby directed into the secondary channel. The sensor located there records the mass flow as a temperature difference. The measurement is performed in a specially shaped flow channel whose wall contains a silicon chip with an etched membrane. A heating resistor and 2 temperature sensors, one upstream and one downstream, are attached on this membrane.

If the heating resistor is fed with a constant voltage, the differential voltage of the temperature sensors indicates the flow rate of the gas flowing over the chip.

Performance Specifications

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 and the base block used for the other gas must be taken into account.

Dimensions

Small Nominal Flow Rates, with Internal Thread

Thread (A)	Thread depth [mm]
G 1/4, NPT 1/4	12
G 1/8, NPT 1/8	12

Product Connections

Analogue Communication

D-Sub plug, 9-pin	Pin	Assignment
1	Digital input
2	GND (for supply voltage and digital input)
3	24 V
4	Relay, normally closed contact
5	Relay, reference contact
6	Set-point value input +
7	Set-point value input GND
8	Actual value output +
9	Actual value output GND
Housing	Shielding

Replacement Instructions (Substitute for 8701, 8711, 8703, 8713)

Type 8741 serves as a compact and technically up-to-date replacement for legacy devices (Type 8701, 8711, 8703, 8713).

Installation Compatibility

• Installation length: The devices have been adapted to be compatible with the installation length.
• Mounting holes: The devices have been adapted to allow for continued use of the existing mounting holes.
• Flange connection: The devices have been adapted to be compatible with the existing flange pattern.

For electrical adaptation, adapter cables are available to connect the new device using existing analogue/D-Sub, PROFIBUS/M12, or RS422/RS485 connections.