Hauck MRO oil-air ratio regulators are designed
to serve as the essential control device in a cross-connected oil-air
delivery system. They support applications requiring wide turndown
and/or low flow rates and repeatability. The MRO is engineered to
function properly over a wide range of air pressures and may be used on
either single or multiple burner applications. A constant oil pressure
is required at the inlet of the regulator.
A connection is provided on the regulator for an
air pressure sensing line. This line extends from the MRO to a
connection on the downstream side of the air control valve in the
secondary combustion air supply line. The MRO translates these air
pressure variations into proportional changes in the oil pressure. The
MRO automatically varies the oil pressure in exact proportion to the air
delivered to the burners. Thus, the desired ratio of oil to air is
constantly maintained.
The MRO’s modular design allows the critical
parts of the regulator to be disassembled for maintenance without
removing the regulator body from the oil piping. Critical elements, such
as the air diaphragm and the valve cartridge, are engineered to allow
them to be removed and replaced as a packaged unit which greatly reduces
and simplifies maintenance requirements.
If the secondary air pressure is greater than 6.9 kPa, an air impulse filtered bleed assembly must be installed
into the air pressure sensing line to the MRO for precise control of
air and fuel oil to the burners. The MRO must be preceded in the oil
line by a suitable filter. Use of clean air and oil greatly enhance the
operational life of the MRO.
The Hauck MRO ratio regulator can be used with No. 1 through No. 6 fuel
oil. It is suitable for use with oil temperatures up to 132ºC.