Burner Technology
Several
patentable features have been included in the INOV8 Waste
Oil Burner design to deal with the carbon precipitation and
gassing-off problems as follows:
- A recirculation system is provided to maintain
high levels of heat transfer (velocities over three feet
per second) as the oil is heated to prevent the occurrence
of the nucleate boiling and graphite precipitation.
- The recirculation system has automatic venting allowing
the released gases to escape and to maintain steady oil
flow to the nozzle.
- The recirculation system in combination with an
automatic vapor eliminator provides a unique feature in
that the oil pump becomes self-priming. In fact, the charged
recirculation loop causes the burner pump to act like a
vacuum pump with very low-pressure capabilities. Most codes
require locating the furnace (unit heater) eight feet off
the floor.
- With all competitive units, it is necessary to
use either a remote floor mounted pump or involve rigorous
priming. The self-contained oil pump on the burner housing
is adequate for most applications.
- A filter is included in the recirculation loop immediately
after the heater circuitry to entrap any small particles
before the oil enters the passage leading to the nozzle.
Competitive units do not have such a practical method to
filter all oil between the heating system and the fine aperture
oil nozzle. The general solution has been to sacrifice good
atomization by using a large aperture nozzle.
- The recirculation loop system pumps hot oil so that
viscosity variations are minimized to maintain uniform firing
rates over wide oil conditions.
- The recirculation system uses a built-in relief
valve of the pump to a desirable advantage. The flow rate
through the valve is ten times greater than what is encountered
in the firing rate of the burner making pressure regulation
much more manageable.
- A pneumatic/mechanical device moves a needle through
the combustion gun to the aperture of the oil nozzle. This
needle will prevent nozzle drip at shut down, will maintain
an open orifice for consistent firing, and will ignite immediately
since oil does not drain out of the final delivery circuit.
 The
fact that other manufacturers of waste oil furnaces use the
less expensive residential combustion controller is not justification
for its use here, particularly when personnel and/or property
would be placed in peril. There have been many cases where
buildings have been destroyed by fire initiated by explosions
of waste oil furnaces. The design of this waste oil furnace
includes a number of innovative concepts directed specifically
to safety and reliability, and yet, this manufacturer is convinced
that a more sophisticated primary combustion control is absolutely
necessary.
The INOV8 burner uses an industrial rated primary safety
control at a cost ten times greater than the aforementioned
residential control. It is an industrially rated control
qualified to monitor combustion equipment as large as 2.5
million BTUH. The primary safety control features the following
programmed sequence:
- An oil temperature interlock to prevent firing of cold
oil.
- An air pressure interlock to prevent oil delivery without
proof of atomizing air.
- A 90 second purge to insure venting of explosive vapors
prior to each start sequence insures there is no residual
fire before introducing new oil
- Start mode consists of a ten second trial-for-ignition
period.
- Automatic sequence from start-mode to run-mode upon flame
detection.
- A three second timing to terminate oil delivery if a
flame outage occurs during run mode.
- One attempt to re-establish flame, but only then, after
repeating steps 1, 2, 3 and 4 above.
- If flame is not detected within the ten second trial-for-ignition
period, the unit reverts to a full safety shutdown wherein
power is terminated to the combustion motor (oil pump) and
the oil heater. After safety shutdown occurs as indicated
by a red light, manual reset is required.
- Termination of spark ignition after flame established
to lengthen the life of the ignition transformer and the
electrodes.
The primary safety control uses an ultra-violet flame detector.
The ultra-violet detector is not sensitive to daylight or artificial
light, as is the case with the cadmium cell detector, previously mentioned.
The ultra-violet sensor will "see" and respond to the flicker of a match or
candle at a distance of four feet, but will not "see" a strong artificial light
at any distance. This feature alone will prevent dangerous situations from
occurring. One of the more appealing aspects of the burner is the serviceability.
The heart of the burner is the "Slide-Out Fire Control Module". It is designed for
ease of servicing and should it need replacing a new Module can be replaced within
five minutes. This Module includes all of the operating controls; temperature sensors,
electric pre-heater and the needle actuator, which could be subject to field failure.
Replacing of this unit would not require highly qualified technicians.
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