Mass Flow Controller (MFC)/ Mass Flow Meter (MFM) for Gases

Transcription

1 Mass Flow Controller (MFC)/ Mass Flow Meter (MFM) for Gases Type 8746 can be combined with Inline MFC/MFM for full scale rates from 2 l N /min to 15 l N /min, MFM up to 25 l N /min High accuracy and repeatability Protection class IP65 Communication via fieldbus based on CNopen Optional: TEX Zone 2 compliance Type ME2X System Control Unit with Gateway functionality Type 8746 for high flow rates can be configured either as MFC or MFM and is intended for the use in a büs or CNopen network. The büs network technology which is based on CN physics was developed by Bürkert especially for applications with quite a number of control loops run by Industrial Ethernet or other fieldbuses. The System Control Unit (SCU) Type ME2X (please see datasheet) transfers a customer s PLC fieldbus into the proprietary büs communication and operates all connected electronic devices. The communication of the devices can be switched from büs to CNopen. Given that, Type 8746 can also be integrated into an existing CNopen infrastructure. Type 8746 meters (MFM) or controls (MFC) the mass flow of gases using an inline sensor. The sensor works according to the thermal principle (constanttemperature anemometer). The measurement is made in the main channel and therefore reaches very fast response times of a few hundred milliseconds. The MFC/MFM can be optionally calibrated for two different gases, the user is able to switch between them. direct-acting solenoid control valve as regulating unit ensures high sensitivity and good flow control of the device. Type 8746 is especially designed for use in harsh environments due to a low sensitivity to contamination, high IP and explosion protection (see p. 2). Technical data Nominal flow range (Q nom ) 2 to 15 l N /min (N 2 ), MFM up to 25 l N /min (N 2 ) Turn-down ratio 5:1 1) Operating medium Neutral, non-contaminated gases, (others on request) Calibration medium Operating gas or air Max. operating 1 bar (with MFCs the max. pressure pressure depends on the orifi ce of the valve) optional up to 25 bar for MFM Medium temperature -1 C to +7 C (-1 C to +6 C with oxygen) mbient temperature -1 C to +45 C (higher temperatures on request) ccuracy ±1.5% v.m. ±.3% v.e. (after 1 min. warm up time) Repeatability ±.1% v.e. Settling (MFC)/ < 5 ms response(mfm) time (t 95% ) Materials Body Stainless steel or aluminium Housing luminium die casting (coated) Seals FKM or EPDM (depending on gas) Port connection G 1/4, 3/8, 1/2, 3/4, 1, NPT 1/4, 3/8, 1/2, 3/4, 1 1) With vertical installation and fl ow downwards the turn-down ratio is 1:1 Technical data Control valve (prop. normally closed valve) Valve orifi ce range.8 to 12 mm k v s value range.2 to 2.5 m 3 /h Electr. connection M12 plug, 5-pin Operating voltage 24V DC Voltage tolerance ± 1% Power consumption Max W (as MFM), Max. 19 to 37 W (as MFC, independent from Proportional valve Type) Residual ripple ± 2% Digital Comm. CNopen or CN based büs Removable memory EEPROM (SIM card: büs relevant data and information about spec. control loop in order to ease replacement) Input-/ Output signals none, communication via bus Protection class IP65 and IP67 TEX compliance II 3G Ex n IIC T4 Gc 2) Dimensions See drawings on p. 4-7 Total weight ca. 1.8 kg (l, 16 W-valve), ca. 3.1 kg (V, 16 W-valve) Installation Horizontal or vertical Device status RGB-LED based on NMUR NE17 2) acc. to DIN EN 679-:21-3 and DIN EN :21 p. 1/9

2 Nom. flow ranges of typical Gase (Other gases on request) Gas Min. Q Nom [l N /min] Max. Q Nom [l N /min] cetylene mmoniac rgon 2 15 Carbon dioxide 2 8 ir 2 15 (MFM 25) Methane 2 75 Propane 2 4 Oxygen 2 15 (MFM 25) Nitrogen 2 15 (MFM 25) Features to fulfill the TEX requirements The operation of Type 8746 without restrictions in Zone 2, Kat. 3 is ensured by the following features: Impact protection cap prevents damage of the M12 plug and all connected elements if mechanical stress is applied. No particular TEX sockets are required Standard requirements for cable glands are fulfilled for versions with external valve Screws prevent uncoupling of the M12 connection under tension Diecast housing maintains IP protection under high mechanical stress LED display protected against mechanical stress M12 plug achieves protection class IP65 and IP67 with and without mounted counterpart Pressure Loss Diagram of a MFM (ref. to air, with 25μm inlet filter) p [mbar] G1/4 G3/8 G1/2 G3/4 G Q [ln/min] The diagram shows exemplarily the pressure loss characteristics when air flowing through. For determining the pressure loss with another gas it needs to calculate the air equivalent and respect the fluidics needed with the other gas. Notes Regarding the Configuration For the proper choice of the actuator orifice within the MFC, not only the required maximum flow rate Q nom, but also the pressure values directly before and after the MFC (p 1, p 2 ) at this flow rate Q nom should be known. In general, these pressures are not the same as the overall inlet and outlet pressures of the whole plant, because usually there are additional flow resistors (tubing, additional shut-off valves, nozzles etc.) present both before and after the controller. Please use the request for quotation form on p. 8 to indicate the pressures directly before and after the MFC. If these should be unknown or not accessible to a measurement, estimates are to be made by taking into account the approximate pressure drops over the flow resistors before and after the MFC, respectively, at a flow rate of Q nom. In addition, please quote the maximum inlet pressure p 1max to be encountered. This data is needed to make sure the actuator is able to provide a close-tight function within all the specified modes of operation. The request form on page 8 contains the relevant fluid specification. Using the experience of Bürkert engineers already in the design phase provide us with a copy of the request containing the necessary data together with your inquiry or order. p. 2/9

3 Measuring Principle This sensor works as a hot-film anemometer in the so-called CT operational mode (Constant Temperature nemometer). To do this, two resistors with precisely specified temperature coefficients located directly in the media flow and three resistors located outside the flow are connected together to form a bridge. The first resistor in the gas flow (RT) measures the fluid temperature, while the second, low-value resistor (RS) is heated so that it is maintained at a fixed, predefi ned over-temperature with respect to the fl uid temperature. The heating current required to maintain this is a measure of the heat being removed by the fl owing gas, and represents the primary measurement. n adequate flow conditioning within the MFC and the calibration with high-quality flow standards ensure that the mass of gas flowing per time unit can be derived from the primary signal with high accuracy. Software Bürkert Communicator Part of Bürkert s new EDIP program (Efficient Device Integration Platform) is the Bürkert Communicator. This software can be run under MS-Windows and allows users to program further parameters in MFCs or watch process controls. It is freely available on Bürkert s website. n accessory part, the büs stick please see ordering chart for accessories, serves as the interface between computer and process instrument I want to connect to. It transfers USB data to CN data. The Communicator allows: - Diagnosis - Parameterization - Registration and storage of process data - Data logging - To watch graph of process - To update firmware of the büs device connected - To program system controls by User-f(x) e.g. gas blending - Pin Configuration M12 Plug, 5-pin (-coded) Pin Configuration 1 SHIELD V Coding 3 DGND 4 CN_H 5 CN_L p. 3/9

4 Dimensions [mm] MFC with valve type 2873 (9 W-coil) 4 x M4 1 4 ca G 1/4; NPT 1/4 G 3/8; NPT 3/8 p. 4/9

5 Dimensions [mm] MFC with valve type 2875 (16 W-coil) 4 x M Version with standard base block ca G 1/4; NPT 1/4 G 3/8; NPT 3/ Version with base block for large nominal flow rates ca G 1; NPT 1 p. 5/9

6 Dimensions [mm] MFC with valve type 2836 (24 W-coil) 4 x M4 1 ca Version with standard base block G 1/4; NPT 1/4 G 3/8; NPT 3/ Version with base block for large nominal flow rates G 1; NPT 1 p. 6/9

7 Dimensions [mm] MFM version 4 x M Version with standard base block G 1/4; NPT 1/4 G 3/8; NPT 3/8 Version with base block for large nominal flow rates G 1; NPT 1 p. 7/9

8 Ordering Chart for ccessories rticle Item no. büs cable extension M12.1m büs cable extension M12.2m büs cable extension M12.5m büs cable extension M12 1m büs cable extension M12 3m Connector M12, female, straight 1) Connector M12, male, straight 1) Connector M12, female, angled 1) Connector M12, male, angled 1) Y junction Y junctionr for connecting two separately powered segments of a büs network Termination resistor 12 Ohm M12 male Termination resistor 12 Ohm M12 female büs-stick Set 1 (incl. cable (M12)) büs-stick Set 2(incl. cable (M12), büs termination, power supply, and software) SIM card on request Software Bürkert Communicator Download from 1) It is possible that the M12 connectors cannot be used together on the same side of a Y-junction. If that is the case, please use a prefabricated cable which uses typically a thinner connector. Male M Female M OR termination resistor male termination resistor female Y junction Y junction Power interrupt The coding of the M12 plug (see p.3) and the housing limit the orientation of the Y or T-junctions. If you select and use your own junctions, please consider these limitations. Female M12 with cable Male M12 with cable Female M p. 8/9

9 MFC/MFM-applications - Request for quotation Please complete and send to your nearest Bürkert sales centre Company Contact person Customer No ddress Postcode/Town Department Tel./Fax MFC-pplication MFM-pplication Quantity Required delivery date TEX compliance Medium data Type of gas (or gas proportion in mixtures) Density kg/m 3 8) Gas temperature [ºC or ºF] ºC ºF Moisture content g/m 3 brasive components/solid particles no yes, as follows: Fluidic data Flow range Q nom Min. l N /min 8) l S /min (slpm) 9) Max. m N3 /h 8) kg/h cm N3 /min 8) cm S3 /min (sccm) 9) l N /h 8) l S /h 9) 1) Inlet pressure at Q nom p 1 = bar(g) Outlet pressure at Q nom p 2 = bar(g) Max. inlet pressure P 1max bar(g) MFC/MFM port connection without screw-in fitting 1/4 G-thread (DIN ISO 228/1) 1/4 NPT-thread (NSI B1.2) with screw-in fitting (acc. to specification for pipeline) mm Pipeline (external Ø) inch Pipeline (external Ø) Flange version Installation horizontal vertical, flow upwards mbient temperature C vertical, flow downwards Material data Body base luminium Stainless steel Seal FKM EPDM Electrical data Signals for set point CNopen or büs and actual value Please quote all pressure values as overpressures with respect to atmospheric pressure bar(ü) 8) 9) 1) at: 1,13 bar(a) and ºC at: 1.13 bar (a) and 2 ºC matches with calibration pressure To find your nearest Bürkert facility, click on the orange box g In case of special application conditions, please consult for advice. Subject to alteration. Christian Bürkert GmbH & Co. KG 155/2_EU-en_89528 p. 9/9