DUNGS MBC-...-VEF, Infinitely variable air/gas ratio control mode

[{"filename":"mbc-vef-dn65-dn100_datasheet_en_238600.pdf","text":"Double solenoid valve\n Combined pressure\n regulator and safety\n valves\n Gas-air-ratio-control\n\n MBC-...-VEF\n DN 65 - DN 100\n\n 7.36\n\n\n\n\n Technical Description Application\n The DUNGS multiple actuator MBC-...-VEF The gas-air ratio regulator permits optimal\n integrates 2 valves and 1 gas-air ratio regu- mixture formation in forced air burners and\n lator in one compact unit: premix burners. This applies to modulating\n and two-stage variable operating modes.\n - Solenoid valves up to 500 mbar (50 kPa) Suitable for gases belonging to gas families\n as per DIN EN 161 Class A Group 2 1, 2, 3 and other inert gaseous media.\n - Fine setting of gas and air pressure ratio\n - Servo pressure regulator as per DIN EN 88 Approvals\n class A group 2; EN 12067-1 EC type testing certificate as per:\n - Internal stepping lines for optimised outlet • EC-Gas Appliances Regulation\n\n\n\n\n Printed in Germany • Edition 01.18 • Nr. 238 600\n pressure stability, external as an option. • EC-Pressure Equipment Directive\n - Flange connection as per ISO 7005 Approvals in other important gas-consum-\n - Easy to install ing countries.\n\n As this system has a modular design, we\n can offer individual solutions with valve\n testing system, mini/maxi pressure switch\n and pressure limiter. Despite the compact\n design, high flow rates can be achieved at\n low pressure difference.\n\n1…8\n\fFunctional Description\nGas flow Schematic diagram MBC-...-VEF\n1.If the valves V1 and V2 are closed, V1 V2\n\n chamber a is subjected to inlet pres-\n sure up to the double seat of the\n valve V1. a b c\n2.The min. pressure switch (option) is p1\n connected to chamber a via a bore pBr\n hole. If the inlet pressure exceeds M\n the desired value set on the pressure V3 V4\n D\n switch, the pressure switch connects 7\n through to the gas burner control\n system. 8 pF\n V N pamb\n3.The valves V1 and V2 open after they Gas/air ratio control\n are enabled by the gas burner control 9\n system. Gas flow through chambers pL\n a, b and c is enabled. V1\t\t Main valve 1 a, b, c\t\t Pressure chambers\n V2\t\t Main valve 2 \t\t in flow direction\n V3\t\t Control valve 3 p1\t\t Inlet pressure\nFunctional description of the com- V4\t\t Control valve 4 pBr Burner pressure, outlet pressure\nbined valve-regulator unit at valve V1 pamb Ambient pressure\nA regulator (pressure regulator unit) M\t\t Working diaphragm\nwith admission pressure compensation D\t\tRestrictor 2, 3, 4, 5 Screw plug G 1/8\n V\t\t Ratio setting 1, 6\t\t Screw plug G 1/4\nis integrated in valve V1. The plunger V1 N\t\t Zero point compensation 7, 8, 9\t\t Stepping line pBr, pF, pL\nis not connected to the valve disc unit.\nWhen the plunger opens, it preloads\nthe compression spring and releases\nthe regulator unit. When the plunger\ncloses, the closing pressure is applied\ndirectly to the valve discs of the regula-\ntor unit. Valves V1 and V2 are driven\ntogether electrically. When valve V3 is\nin the closed position, it closes off the\npressure chamber under the working\ndiaphragm M so that this chamber is\nnot affected by the inlet pressure p1\nin chamber a. The plunger of valve V1\ncontrols the valve V3. The pressure un-\nder the working diaphragm M depends\non a variable flow cross-section D. The\ncomparison diaphragms for burner\npressure pBr and blower pressure pL\nare connected with a bar. The ratio V\ncan be set by shifting the bearing point.\nThe zero point compensation N acts on\nthis bar. Ambient pressure pamb or firing\nchamber pressure pF must be applied\nto the opposite side of the comparison Pressure taps, gas train diagram\ndiaphragms. The firing chamber over-\npressure reduces the burner pressure MBC-...-VEF 8 1 2 3 4 5 9\nwhen the ratio V > 1. If there are any\nchanges in the equilibrium of forces,\nthe flow cross-section D after the valve\nV4 is changed. The pressure under the 7\n 6\nworking diaphragm is re-adjusted, and\n 10\nthe valve disc unit V1 changes the free\ncross-section.\n 8 1 2 3 4 11 12 5 9\nFunctional description valve V2\nThe plunger of the valve V2 is con- diaphragm M so that this area is not\nnected to the valve disc unit. When the affected by the burner pressure.\nplunger opens, it preloads the com-\npression spring. The valve V2 opens Closing function\ncompletely without any delay. The valve If there is an interruption in the power\nV4 is actuated by the valve V2. When supply to the solenoid coils of the main\nthe valve V4 is in the closed position, valves V1 and V2, they are closed by\nit closes off the area under the working the compression springs in <1s.\n 2…8\n\f Technical Data\n\n Nominal widths DN\t\t65\t\t80\t\t100\n Connection flanges as per EN 1092-1 for welding neck flanges as per\n DIN 2633 (PN16) DN 65 - DN 100\n Length as per DIN 3202 part 1, series F1.\n\n Max. operating overpressure 500 mbar (50 kPa)\n Inlet pressure range pe : 15 mbar (1.5 kPa) to 360 mbar (36 kPa)\n Burner pressure range pBr : 0,5 mbar (0.05 kPa) to 100 mbar (10 kPa)\n Guiding range pL : 0,4 mbar (0.04 kPa) to 100 mbar (10 kPa)\n\n Media Gases belonging to gas families 1, 2, 3 and other inert gaseous media.\n\n Ambient temperature -15 °C to +60 °C\n\n Dirt trap device Filter. A suitable gas filter must be connected upstream.\n For further information, see data sheet 11.02 “Gas and air filter”.\n\n Pressure switch The system can be equipped with pressure switch types GW A5, ÜB A2, NB A2 as per DIN\n EN 1854. In case of DN 65 GW…A5 cannot be mounted on item 2. For further information,\n see data sheets 5.07 and 5.02 “Pressure switches for DUNGS multiple actuators”.\n\n Servo pressure regulator Pressure regulator with admission pressure compensation, sealed with valve\n V1 when switched off, as per DIN EN 88 Class A\n Gas-air ratio regulator with adjustable ratio V as well as zero point compensation\n N and firing chamber pressure connection\n\n Ratio setting range V Ratio V = pBr / pL 0.75 : 1 … 3 : 1, other ratios on request\n\n Zero point compensation N possible\n\n Solenoid valve V1, V2 Valve as per DIN EN 161 Class A Group 2; fast-closing, fast-opening\n\n Measuring gas connection G 1/4 DIN ISO 228; at inlet and outlet flanges, G 1/8 on both sides after the filter,\n on both sides between V1 and V2, after V2 (if the pressure switch is assembled,\n it may not be possible to install a measuring gas connection in some cases)\n\n Burner pressure monitoring device pBr after valve V2\n\n Stepping line G 1/8 connection as per DIN ISO 228 for burner pressure (pBr; gas)\n Stepping and connection lines must be made of steel and ≥ PN1, DN4. Con-\n densate from stepping and connection lines may not enter the fitting. The\n operating and assembly instructions must be strictly followed.\n\n Voltage / frequency ~ (AC) 50 -60 Hz 230 V -15 % +10 %\n Standard voltages:…