Burner installations and methods of commissioning and operating burner installations

Abstract

A burner installation includes a stack, a burner, a fuel valve, an air valve and a control device including a store storing burner pairs of values of air and fuel valve settings at firing rates and for controlling air and fuel valve settings. A stack flow regulator adjusts flow of combustion products through the stack and a pressure sensing arrangement monitors pressure of combustion products downstream of the burner. Respective pairs of stack flow regulator setting values and a measured value from the pressure sensing arrangement are stored for pairs of air and fuel valve settings values. The control device receives a feedback signal from the pressure sensing arrangement for comparing an actual pressure value with a stored pressure value and to trim the stack flow regulator setting to cause the actual pressure value from the pressure sensing arrangement to move closer to the stored pressure value.

1 . A burner installation comprising a stack and a burner upstream of the stack for burning fuel in air to produce combustion products which are passed into the stack; a fuel valve for adjusting flow of fuel to the burner; an air valve for adjusting flow of air to the burner; a control device including a store arranged to store pairs of values of air and fuel valve settings at various firing rates of the burner and for controlling the air and fuel valve settings in dependence upon the stored air and fuel valve settings; a stack flow regulator for adjusting flow of combustion products through the stack; and a pressure sensing arrangement for monitoring pressure of combustion products downstream of the burner; wherein the store is arranged for storing respective pairs of values of a setting of the stack flow regulator and a measured value from the pressure sensing arrangement for the pairs of values of air and fuel valve settings; and wherein the control device is arranged to receive a feedback signal from the pressure sensing arrangement for comparing an actual pressure value with a stored pressure value and to trim the setting of the stack flow regulator to cause the actual pressure value from the pressure sensing arrangement to move closer to the stored pressure value. 
     
     
         2 . A burner installation according to  claim 1 , wherein the burner installation further comprises a flue for conveying combustion products from the burner to the stack. 
     
     
         3 . A burner installation according to  claim 2 , wherein the stack flow regulator is disposed in the flue. 
     
     
         4 . A burner installation according to  claim 1 , wherein the stack flow regulator comprises a valve having one or more vanes. 
     
     
         5 . A burner installation according to  claim 1 , wherein the pressure sensing arrangement comprises a pressure sensor upstream of the stack flow regulator 
     
     
         6 . A burner installation according to  claim 5 , wherein the pressure sensing arrangement is a differential pressure sensing arrangement and is arranged to measure a pressure difference between the pressure sensor upstream of the stack flow regulator and ambient pressure. 
     
     
         7 . A burner installation according to  claim 6 , wherein the pressure sensing arrangement is connected to the control device to provide a pressure value representing the difference in pressure measured between the pressure sensor upstream of the stack flow regulator and ambient pressure. 
     
     
         8 . A method of operating a burner installation, comprising the following steps:
 providing a burner installation comprising a stack and a burner upstream of the stack for burning fuel in air to produce combustion products which are passed into the stack, a fuel valve for adjusting flow of fuel to the burner, an air valve for adjusting flow of air to the burner, a control device including a store, a stack flow regulator for adjusting the flow of combustion products through the stack, and a pressure sensing arrangement for monitoring pressure of combustion products downstream of the burner;   storing, at various firing rates of the burner, pairs of values of air and fuel valve settings and associated pairs of values of a setting of the stack flow regulator and a measured value from the pressure sensing arrangement;   operating the burner and controlling the air and fuel valve settings and the stack flow regulator valve setting in dependence upon the stored air and fuel valve settings and the associated stack flow regulator setting;   receiving at the control device a feedback signal of an actual pressure value from the pressure sensing arrangement;   comparing the actual pressure value from the feedback signal with a stored pressure value; and   trimming the setting of the stack flow regulator to cause the actual pressure value from the pressure sensing arrangement to move closer to the stored value.   
     
     
         9 . A method according to  claim 8 , wherein the pressure sensing arrangement measures a pressure difference between a pressure sensor upstream of the stack flow regulator and ambient pressure, and the pressure difference is a pressure value fed back as a signal to the control device. 
     
     
         10 . A method of commissioning a burner installation, comprising the following steps:
 (i) providing a burner installation comprising a stack and a burner upstream of the stack for burning fuel in air to produce combustion products which are passed into the stack, a fuel valve for adjusting flow of fuel to the burner, an air valve for adjusting flow of air to the burner, a control device including a store, a stack flow regulator for adjusting flow of combustion products through the stack, and a pressure sensing arrangement for monitoring pressure of combustion products downstream of the burner;   (ii) adjusting air and fuel valve settings to positions where desired combustion conditions are obtained for a, first firing rate of the burner,   (iii) storing the pair of values of air and fuel valve settings that provide the desired combustion conditions;   (iv) adjusting a setting of the stack flow regulator to a position where, for the first firing rate of the burner, a desired stack flow of combustion products is obtained;   (v) storing a value of the setting of the stack flow regulator and the pressure value from the pressure sensing arrangement with the values of the air and fuel valve settings; and   (vi) repeating steps (ii) to (v) above at other firing rates of the burner.   
     
     
         11 . A method according to  claim 10 , wherein the pressure sensing arrangement measures a pressure difference between a pressure sensor upstream of the stack flow regulator and ambient pressure, and the pressure difference is the pressure value stored. 
     
     
         12 . A method according to  claim 10 , further comprising the following subsequent steps:
 operating the burner, controlling the air and fuel valve settings in dependence upon the stored air and fuel valve settings, and setting the stack flow regulator according to the value stored in association with the air and fuel valve settings;   receiving at the control device a feedback signal of an actual pressure value from the pressure sensing arrangement;   comparing the actual pressure value from the feedback signal with the stored pressure value associated with the stack flow regulator setting value; and   trimming the setting of the stack flow regulator to cause the actual pressure value from the pressure sensing arrangement to move closer to the stored value.   
     
     
         13 . A method according to  claim 12 , wherein the pressure sensing arrangement measures a pressure difference between a pressure sensor upstream of the stack flow regulator and ambient pressure, and the pressure difference is the pressure value fed back as a signal to the control device. 
     
     
         14 . A method according to  claim 12 , wherein the setting of the stack flow regulator is trimmed until the actual pressure value from the pressure sensing arrangement is the stored value.