Compensator for controlling airflow in fired heater

Abstract

A compensator, system, and method of controlling airflow through a fired heater or furnace. The compensator has a stationary plate disposed across the burner intake and a movable plate disposed adjacent to the stationary plate that is movable between first and second lateral positions to control the airflow through the intake. In the first lateral position, second openings of the movable plate are at least partially aligned with first openings of the stationary plate, thereby defining a first level of airflow through the intake. In the second lateral position, the second openings of the movable plate are at least partially misaligned with the first openings of the stationary plate, thereby defining a second level of airflow through the intake. The airflow through the intake at the second level is less than the air flow through the intake at the first level.

What is claimed is: 
     
         1 . A compensator for a burner of a fired heater or furnace, the burner having an intake for airflow, the compensator comprising:
 a stationary plate disposed across the intake and across a direction of the airflow through the intake, the stationary plate including one or more first openings; and   a movable plate disposed adjacent to the stationary plate and including one or more second openings, the movable plate being movable between first and second lateral positions with respect to the stationary plate to control the airflow through the intake,   wherein in the first lateral position, the one or more second openings of the movable plate are at least partially aligned with the one or more first openings of the stationary plate, thereby defining a first level of airflow through the intake,   wherein in the second lateral position, the one or more second openings of the movable plate are at least partially misaligned with the one or more first openings of the stationary plate, thereby defining a second level of airflow through the intake, and   wherein the airflow through the intake at the second level is less than the air flow through the intake at the first level.   
     
     
         2 . The compensator of  claim 1 , wherein in the first lateral position, the one or more second openings are substantially aligned with the one or more first openings such that the first level is a maximum amount of airflow allowed through the intake, and in the second lateral position, the one or more second openings are substantially misaligned with the one or more first openings such that the second level is a minimum amount of airflow allowed through the intake. 
     
     
         3 . The compensator of  claim 1 , wherein the first and second openings are configured to vary the airflow for the intake in a linear relationship between the first and second levels with the movement of the movable plate between the first and second lateral positions. 
     
     
         4 . The compensator of  claim 1 , further comprising a movable support member being movable in a lateral direction relative to the stationary plate that is generally transverse to the direction of the airflow through the intake, the movable plate being releasably coupled to the movable support member, and the movable support member being configured to move the movable plate with respect to the stationary plate between the first and second lateral positions. 
     
     
         5 . The compensator of  claim 4 , wherein the movable support member is a slidable elongated bar. 
     
     
         6 . The compensator of  claim 4 , further comprising an actuator configured to slide the bar with respect to the stationary plate. 
     
     
         7 . The compensator of  claim 4 , wherein a coupling removably connects the movable plate to the bar, and the coupling comprises a mount disposed on the movable plate, a flange disposed on the bar, and a locking pin removably connecting the flange to the mount. 
     
     
         8 . The compensator of  claim 1 , further comprising a housing configured to affix to the burner and having an opening, a first end of the housing communicating with the intake, and a second end of the housing having the stationary plate disposed across the opening. 
     
     
         9 . The compensator of  claim 1 , further comprising a breaker plate disposed adjacent to the movable plate and being configured to interrupt the airflow to the first and second openings to address interference due to wind directions. 
     
     
         10 . The compensator of  claim 1 , further comprising a friction reducer supporting the movable plate on the compensator. 
     
     
         11 . The compensator of  claim 10 , wherein the friction reducer comprises a support plate, track, or guide disposed between a first surface of the movable plate and a second surface of the compensator. 
     
     
         12 . The compensator of  claim 1 , further comprising at least one sensor being configured to measure one or more characteristics associated with operation of the burner, and a controller in communication with the sensor and being configured to control the moveable plate based on the measured characteristic to adjust the airflow through the intake. 
     
     
         13 . The compensator of  claim 12 , wherein the sensor comprises one or more of an oxygen sensor, a fuel gas BTU sensor, and a calorimeter. 
     
     
         14 . The compensator of  claim 1 , further comprising a curb disposed between the movable plate and the stationary plate on each side of the one or more first openings, the curbs being configured to reduce leakage of the air from the sides between the plates. 
     
     
         15 . The compensator of  claim 1 , wherein the one or more first openings comprise two first openings having a first width in the lateral direction, the two first openings separated by a first separation at least as great as the first width, and wherein the one or more second openings comprise two second openings having a second width in the lateral direction, the two second openings separated by a second separation at least as great as the second width. 
     
     
         16 . The compensator of  claim 15 , wherein the first width is substantially equal to the second width; wherein the first separation is substantially equal to the second separation. 
     
     
         17 . The compensator of  claim 15 , wherein a first shape of the first openings is the same as a second shape of the second openings. 
     
     
         18 . The compensator of  claim 1 , wherein the one or more first and second openings each comprise a quadrilateral having sides of unequal length, vertical ones of the sides being parallel to one another, a lateral one of the sides being orthogonal to the vertical sides, another lateral one of the sides being oblique to the vertical sides. 
     
     
         19 . A compensator system for a fired heater or furnace having a plurality of burners, each burner having an intake for airflow, the compensator system comprising:
 at least one movable support member being movable laterally relative to the intakes in a direction generally transverse to a direction of the airflow;   a plurality of stationary plates disposed across the intakes of the burners, respectively, each of the stationary plates including one or more first openings; and   a plurality of movable plates disposed adjacent to the plurality of stationary plates, respectively, each of the movable plates including one or more second openings, and each movable plate being releasably coupled to the movable support member; and   a controller configured to move each of the plurality of movable plates between first and second lateral positions via movement of the moving support member to control the airflow through the intake of each burner, respectively,   wherein in the first lateral position, the one or more second openings of each movable plate are at least partially aligned with the one or more first openings of a respective stationary plate, thereby defining a first level of airflow through the intake of each burner, respectively,   wherein in the second lateral position, the one or more second openings of each movable plate are at least partially misaligned with the one or more first openings of the respective stationary plate, thereby defining a second level of airflow through the intake of each burner, respectively, and   wherein the airflow at the second level is less than the air flow at the first level.   
     
     
         20 . The compensator system of  claim 19 , wherein the controller is configured to move each of the movable plates between the first and second lateral positions at substantially the same time via the movable support member. 
     
     
         21 . The compensator system of  claim 20 , wherein the controller automatically controls the airflow between the first and second levels. 
     
     
         22 . The compensator system of  claim 19 , wherein an actuator coupled to the movable support member is configured to slide the movable support member with respect to the stationary plates. 
     
     
         23 . The compensator system of  claim 22 , wherein the movable support member is an elongated bar. 
     
     
         24 . The compensator system of  claim 19 , further comprising a bearing configured to support the bar to a portion of the fired heater. 
     
     
         25 . A method of controlling airflow through a fired heater or furnace comprising the step of adjusting the airflow using the compensator system according to  claim 19 . 
     
     
         26 . A fired heater or furnace, comprising:
 a radiant firebox having a floor, walls, a roof, and a stack;   a plurality of burners disposed in the firebox at the floor, walls, or roof, each of the burners having an intake for airflow; and   a compensator according to  claim 1  disposed at the intake of one or more of the burners.   
     
     
         27 . The fired heater or furnace of  claim 26 , wherein the burners are arranged in at least two rows; and at least two movable support members are each arranged on one of the at least two rows. 
     
     
         28 . The fired heater or furnace of  claim 27 , further comprising at least one actuator coupled to the at least two movable support members and being configured to move the at least two movable support members along the rows. 
     
     
         29 . The fired heater or furnace of  claim 28 , wherein each movable support member is an elongated bar. 
     
     
         30 . The fired heater or furnace of  claim 26 , wherein a controller is configured to automatically adjust the airflow through one or more of the burners via one or more of the compensators between the first and second levels.