Bentone BG 450-2 Two-Stage Gas Burner 120-550 kW

Overview

The Bentone BG 450-2 is a two-stage gas burner at the top of Bentone’s intermediate family, above the BG 300 and BG 400. Bentone lists the BG 450 family at 90 to 550 kW and approves it to EN 676, with Annex J/K builds to EN 746-2 for industrial ovens, kilns and steam boilers. The two-stage BG 450-2 with LME22 control and a DUNGS MB-ZRDLE 412 to 420 gas train is documented in its manual at 120 to 550 kW on all four test gases, G20, G25, G30 and G31.

Seven Star LLC supplies the Bentone BG 450-2 and its replacement parts to facility managers, boiler contractors and plant engineers in Oman and across the GCC, with engineering support in Muscat. At up to 550 kW this burner is sized for the main boilers of large hotels, hospitals, shopping malls, laundries and process plants, where a two-stage firing pattern gives a useful turndown without the cost of full modulation.

Operating Principle

Each start of the Bentone BG 450-2 follows the LME22 programme: air pressure check, fan start, a 20 second prepurge and 3 seconds of pre-ignition before the start gas is released and lit. An ionisation probe supervises the flame; the manual specifies a minimum ionisation current of 5 microamps with flame and a maximum of 20 microamps, a lockout within 3 seconds if no flame forms and a reaction within 1 second if the flame is lost. Faults are shown by a multi-coloured LED that blinks a code, for example two blinks for no flame at the end of the safety time and three blinks for an air pressure switch fault.

After ignition the Bentone BG 450-2 settles at stage 1 and steps up to stage 2 on demand. The air damper is moved by a damper motor whose cam discs define the closed, low-load and high-load positions, and a cam also switches the stage 2 gas valve. On the gas side the MB-ZRDLE has a 360 mbar maximum inlet pressure and slow-opening valves with separate start load, stage 1 and stage 2 adjustment. Its regulator range depends on size: 4 to 50 mbar for the 405 to 412 S50, and 4 to 20 mbar (S20) or 20 to 50 mbar (S50) for the 415 and 420. Bentone recommends 4 plus or minus 1 percent O2 in the flue gas.

Engineering Design of the Bentone BG 450-2

The larger housing of the Bentone BG 450-2 accepts three flame tube lengths, 256, 356 and 456 mm, giving insertion depths (dimension A) of 226, 326 and 426 mm, with tube diameters of 159 and 162 mm at measures B and C. For the boiler connection the manual gives a bolt circle of 255 to 290 mm, or 210 mm as an alternative, and an opening of 170 mm. The flange dimensions of the Bentone BG 450-2 are markedly larger than on the BG 400, so the two burners are not interchangeable on the same boiler front without checking the flange.

Electrical supply to the Bentone BG 450-2 is 230 V single-phase at 50 Hz with a current of 4.6 A and IP20 protection. Unlike the smaller burners, the manual lists two fuse ratings: 6.3 A for the operating circuit and 10 A for the motor. The NOx class is 3 and the sound power level is 89 dBA. The wiring diagram shows a main switch, a stage II indicator lamp, the damper motor and two solenoid valves, so the burner panel gives operators a clear view of firing state.

Key Features

The Bentone BG 450-2 brings the following documented features to larger heating and process plants:

• A two-stage firing range of 120 to 550 kW applies to natural gas G20 and G25 and to LPG G30 and G31.
• NOx class 3 on all gases is stated in the technical specification.
• Three flame tube lengths, 256, 356 and 456 mm, suit deep or shallow combustion chambers.
• The Siemens LME22 control provides ionisation flame supervision and blink-code fault diagnosis.
• The DUNGS MB-ZRDLE gas train is available from the 407 up to the 420 size to match gas pressure and flow.
• A cam-adjusted damper motor sets closed, low-load and high-load air positions and can be released for service.
• Separate operating and motor fuses protect the control circuit and the fan motor independently.
• Service once a year or every 3,000 operating hours is recommended, including filter, electrodes, brake plate, motor and fan wheel.

Industrial Applications

Typical duties for the Bentone BG 450-2 are hot water and steam boilers in the 120 to 550 kW range, larger air heaters and industrial ovens. Users include hotel and hospital central plant rooms, commercial laundries, district heating substations, food and beverage factories and paint or drying lines, where load varies but a full modulating burner is not required. Two-stage operation reduces the number of starts compared with on-off firing, which lowers purge losses and wear.

Across Oman, from Muscat to the Duqm, Sohar and Salalah industrial areas, Seven Star LLC can supply the Bentone BG 450-2 together with flame supervision and gas train parts such as the Lamtec FFS08 Flame Sensor for Burner Flame Monitoring, the Dungs GW A6 Compact Pressure Switch for Gas and Air and the DUNGS VPS 504 219881. Smaller boilers are covered by our Bentone BG 300 and BG 400 pages.

Technical Specifications

Bentone BG 450-2 values below are reproduced from the manufacturer’s LME22 MB-ZRDLE 412-420 manual, available as a download on this page, and from the bentone.com model table.

How to Order

Need a Bentone BG 450-2 or parts for one already in service? Send Seven Star LLC the burner designation and article number from its label, the fuel and the boiler output, and we will confirm the configuration from the attached manual and arrange delivery within Oman and the GCC.