DUNGS MBC-300/700/1200-VEF, Infinitely variable air/gas ratio control mode

[{"filename":"mbc-300-700-1200-vef_datasheet_en_243549.pdf","text":"GasMultiBloc\n Combined regulator and\n safety valve\n Gas-air-ratio-control\n\n MBC-300-VEF\n MBC-700-VEF\n MBC-1200-VEF\n\n 7.03\n\n\n\n\n • Max. operating pressure\n 360 mbar (36 kPa)\n\n • Compact design\n\n • High flow values\n\n • Low weight\n\n • Low power consumption\n\n • Modulating mode\n\n • Adjustable outlet pressure up\n to 300 mbar (30 kPa)\n\n • Other available servo pres-\n sure regulator models:\n\n - zero pressure\n\n - constant pressure\n\n • Mountable accessories\n Technical Description Application\n - Pressure switch The DUNGS multiple actuator MBC…VEF The servo pressure regulator permits\n offers filter, valves and servo pressure optimum mixture formation in forced air\n regulator in one compact unit: burners and premix burners; this applies\n - VPS\n to modulating and multi-stage variable\n - Dirt trap: microfilter operating modes.\n • Ratio V = pBr / pL = 0.4:1…3:1 - 2 solenoid valves up to 360 mbar (36 kPa) Suitable for gases of gas families 1, 2, 3\n as per DIN EN 161 class A group 2 and other neutral gaseous media.\n • Zero point correction possible - Servo pressure regulator as per DIN EN\n 88 class A group 2; EN 12067-1 Approvals\n • Internal pulse line pBr - Fine setting of gas and air pressure ratio EC type testing certificate as per:\n\n\n\n\n Printed in Germany • Edition 2025.01 • Nr. 243 549\n - Flange connections with pipe threads as • EC-Gas Appliances Regulation\n per ISO 7/1 or NPT • EC-Pressure Equipment Directive\n - Easy to install Approvals in other important gas-consum-\n - Low weight ing countries.\n\n As this system has a modular design, we\n can offer individual solutions with valve\n inspection system, pressure switches mini/\n maxi and pressure limiters. High flow values\n at low pressure difference.\n\n1…8\n\fFunctional Description\nGas flow Block diagram MBC...VEF\n1. If the V1 and V2 valves are closed,\n chamber a is under inlet pressure. a b\n2. The min. pressure switch (option) is p1 R\n pBr\n connected to chamber a via a bore-\n hole. M pBr pBr\n If the inlet pressure exceeds the D internal\n standard\n external\n option\n\n reference value set in the pressure\n switch, the switch switches through S1\n\n to the automatic burner control.\n3. The V1 and V2 valves open after they V\n pF\n pamb\n are enabled by the automatic burner\n control.\n S2 N pL\n Gas flow through the chambers a\n and b is enabled.\n M Working diaphragm a, b Pressure chambers\nFunctional description of the valve- D Restrictor in flow direction\nregulator combination S1 Servo diaphragm for burn- p1 Inlet pressure\nValves V1 and V2 can be controlled er pressure pBR pBr Burner pressure,\nelectrically and independent of each S2 Servo diaphragm for blow- outlet pressure:\nother. Each valve pretensions its own er pressure pL Pamb Ambient pressure\npressure spring when the plunger R Regulator disc pL Blower pressure\nopens. If both valves are open, a pres-\nsure pulse is sent under the working\ndiaphragm M. The intensity of this pres-\nsure pulse changes depending on the\nadjustable restrictor point D. 16\n\n\nThe comparison diaphragms S1 for\n 15\n 14\n\nburner pressure pBr and S2 for blower 11 13\n\n\npressure pL are connected with each\nother via a rod. The ratio V can be set\n 10\n 9\n\nby shifting the bearing point.\nZero point correction N acts on this rod\nmechanism via the air diaphragm S2. 8\n\nAmbient pressure pamb or firing chamber 7\n 6 V1\npressure pF must be applied to the area 5 V2 12\n\nbetween the comparison diaphragms. 4\n\n\nThe firing chamber pressure reduces p1 pBr\n\nthe burner pressure at a ratio of V > 1.\n 18\n\n 3 17\n\nChanges in the equilibrium of forces 2\n\nresult in a change in the flow cross- 1\n pF\n\nsection. pL\nThe pressure under the working dia-\nphragm is re-adjusted. The regulator\nunit adapts the free valve cross-section 1 Pressure regulator unit 8 Plunger V1 15 Solenoid V2\ndepending on the new flow require- 2 Regulator spring 9 Solenoid V1 16 Solenoid housing\nment. 3 Connecting flange 10 Printed circuit board Setting:\n 4 Micro-filter 11 Electrical connection 17 Gas-air ratio\nClosing function 5 Valve V1 12 Valve V2 18 Zero point\nIf the supply voltage of the solenoid 6 Closing spring V1 13 Closing spring V2 correction\ncoils of V1 and V2 valves is interrupted, 7 Housing 14 Plunger V2\nthe pressure springs close the valves\nin <1s. Pressure taps, gas train diagram\n MBC...VEF\n\n 2 3 4\n\n\n\n…