Apparatus for Oil Flow Control

Abstract

The current invention discloses a method of controlling the flow rate of a heavy fuel oil in a fluid transfer apparatus having a point of use outlet to a boiler. It not only controls the flow rate of the fuel oil directly, but also indirectly control the viscosity of the fuel oil without measuring its viscosity. It relies on combustion curves established during the commissioning period using a typical fuel oil at a predetermined trim heater temperature. During normal operation, it sets the flow control valve according to the combustion curves, measures the flow rate and compares to the flow rate target. Instead of using the flow rate measurement feedback to control the flow control vale, it modulates the trim heater to vary the viscosity to arrive at the desired flow rate.

What is claimed is: 
     
         1 . An apparatus for controlling a fuel oil, comprising
 An oil pump  10  for drawing the fuel oil from a source and raising a pressure of the fuel oil;   A pressure regulator  15  for regulating the pressure of the fuel oil downstream of the pressure regulator to a desired value;   A trim heater  20  for controlling a temperature of the fuel oil;   A temperature sensor  30  for measuring the temperature the fuel oil;   A flow control valve (FCV)  40  for controlling a flow rate of fuel oil;   A flow meter  50  for measuring the flow rate of the fuel oil;   A combustion controller  70 ;   A heater controller  90 ; and   A burner capable of burning said fuel oil in a boiler, wherein the combustion controller  70  receives a call for heat signal from the boiler, and determines a target flow rate of the fuel oil for the heater controller  90  and a target setting for the FCV  40 ; the heater controller  90  receives feedback signals from the temperature sensor  30  and the flow meter  50 , and controls the trim heater  20  to drive the flow rate of the fuel oil toward the target flow rate of the fuel oil.   
     
     
         2 . The apparatus in  claim 1 , wherein the combustion controller  70  receives a call for heat signal from the boiler, and calculates the target flow rate of the fuel oil according to a combustion curve established during a commissioning period and sends a signal to inform the heater controller  90  regarding the target flow rate, and calculates the target setting for the CFV  40 , and sends a commend signal to drive the FCV to the target setting. 
     
     
         3 . The apparatus in  claim 1 , wherein the fuel oil is a heavy fuel oil. 
     
     
         4 . The apparatus in  claim 1 , wherein the heater controller  90  sets a higher temperature setpoint for the trim heater  20  when the flow rate measured by the flow meter  50  is lower than the target flow rate set by the combustion controller  70  in order to drive the measured flow rate toward the target flow rate, and vice versa. 
     
     
         5 . The apparatus in  claim 1 , wherein the burner is capable of burning both the fuel oil and a gaseous fuel. 
     
     
         6 . The apparatus in  claim 1 , wherein the burner includes a forced-draft combustion blower and an oil atomization gun. 
     
     
         7 . The apparatus in  claim 6 , further comprising a flue gas recirculation (FGR) duct and an FGR control damper.