The problem:
Cochran Steam boilers (10,000lb/hr) were installed on site and fitted with a Hamworthy Combustion burner. This burner was of the rotary cup design and its air/fuel ratio was controlled by ‘cam and cable’ which is no longer supported by the manufacturer and spares are obsolete.
Also, the existing burner has mechanical linkages along with a fixed speed fan causing hysteresis within the gas/air control with the fan operating at full speed regardless of combustion air requirements.
The Solution:
The Hamworthy burner was removed and replaced with an OilonUk RP-280 M HFO fully modulating pressure jet burner, complete with fully integrated Ecosafe controls.
The upgrade virtually eliminated any inherent hysteresis by controlling the air and oil servos to 0.1 of a degree and running self-checks to ensure repeatability without any drift. Due to a tighter level of gas/air ratio control, the burner operated at lower oxygen levels with an increased turn down ratio, achieving substantial fuel savings.
There was also substantial saving in electrical running costs due to the VSD optimising the FD fans speed to match the burner’s modulation.
The Ecosafe burner control system operated with its own fully adjustable PID pressure control and accepted a remote set point input (4-20mA). The burner control panel installed alongside the boiler incorporated the existing water level controls.
All existing boiler interlocks /controls were retained and electrical submitted for approval.