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NORA Oilheat Technicians Manual

Figure 5-17: Delavan ProTek valve ries, such as firebrick, tend to radiate more heat after shut down and thus are more likely to have this type of after-drip. To prevent this, line old refractory with ceramic. Oilburner nozzle anti-drip valves Another solution is the use of nozzles with check valves. These nozzles are designed to cut-off fuel flow from the nozzle quickly. See Figures 5-16 and 5-17. Nozzle check valves also eliminate the incomplete atomization that can occur on start up and shut down of the oilburner. They also eliminate after-drip associated with air bubbles in the nozzle line or expansion of the oil caused by reflected heat from the combustion chamber. Figure 5-18 shows how these valves reduce hydrocarbon (smoke) emissions. These check valves are built into the nozzle strainer assembly and must be installed or changed at the time the nozzle is changed. The check valve is calibrated to open and close within a very tight tolerance of the burner operating pressure. For this reason, different nozzle check valves are manufactured to match different operating pressures. If you are about to change the operating pressure of a burner, you should first check to see if it has a check valve installed. If it does, be sure to install the right check valve for the new operating pressure. Figure 5-18: Standard vs. anti-drip valve; emissions chart. Dark tint area is a standard nozzle, light shaded area is with a nozzle check valve. 5-16 Nozzles and Combustion Chambers Figure 5-16: Hago Ecovalve Without Check Valve With Check Valve Chapter 5 Nozzles and Chambers Burner Start Burner off Hydrocarbons PPM Steady State


NORA Oilheat Technicians Manual
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