CA2541606A1 - Control of an adjustable secondary air controller for a burner - Google Patents
Control of an adjustable secondary air controller for a burner Download PDFInfo
- Publication number
- CA2541606A1 CA2541606A1 CA002541606A CA2541606A CA2541606A1 CA 2541606 A1 CA2541606 A1 CA 2541606A1 CA 002541606 A CA002541606 A CA 002541606A CA 2541606 A CA2541606 A CA 2541606A CA 2541606 A1 CA2541606 A1 CA 2541606A1
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- Prior art keywords
- controller
- valve
- air
- burner
- pressure
- Prior art date
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- Granted
Links
- 238000000034 method Methods 0.000 claims abstract description 50
- 239000000446 fuel Substances 0.000 claims description 67
- 238000009966 trimming Methods 0.000 claims description 24
- 238000010438 heat treatment Methods 0.000 claims description 22
- 238000004891 communication Methods 0.000 claims description 6
- 238000013022 venting Methods 0.000 claims description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 abstract description 24
- 239000003345 natural gas Substances 0.000 abstract description 12
- 230000018044 dehydration Effects 0.000 abstract description 6
- 238000006297 dehydration reaction Methods 0.000 abstract description 6
- 238000004519 manufacturing process Methods 0.000 abstract description 5
- 238000012545 processing Methods 0.000 abstract description 5
- 239000007788 liquid Substances 0.000 abstract description 4
- 239000003209 petroleum derivative Substances 0.000 abstract description 4
- 239000003570 air Substances 0.000 description 185
- 239000007789 gas Substances 0.000 description 37
- 230000008569 process Effects 0.000 description 33
- 238000010304 firing Methods 0.000 description 32
- 230000001276 controlling effect Effects 0.000 description 22
- 238000002485 combustion reaction Methods 0.000 description 18
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 14
- 239000001301 oxygen Substances 0.000 description 14
- 229910052760 oxygen Inorganic materials 0.000 description 14
- 230000035900 sweating Effects 0.000 description 11
- 230000004044 response Effects 0.000 description 9
- 230000007423 decrease Effects 0.000 description 8
- 238000010926 purge Methods 0.000 description 7
- 230000003247 decreasing effect Effects 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 230000008901 benefit Effects 0.000 description 4
- 230000006835 compression Effects 0.000 description 4
- 238000007906 compression Methods 0.000 description 4
- 238000013461 design Methods 0.000 description 4
- 239000002737 fuel gas Substances 0.000 description 4
- 230000004913 activation Effects 0.000 description 2
- 239000012080 ambient air Substances 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000004880 explosion Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000033228 biological regulation Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- GUIJLPKNGJMXKV-AZUAARDMSA-N rod-188 Chemical compound C1=CC(C)=CC=C1S(=O)(=O)N1[C@@H]([C@H]2OC(=O)CC2)C2=CC=CC=C2CC1 GUIJLPKNGJMXKV-AZUAARDMSA-N 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N3/00—Regulating air supply or draught
- F23N3/04—Regulating air supply or draught by operation of single valves or dampers by temperature sensitive elements
- F23N3/042—Regulating air supply or draught by operation of single valves or dampers by temperature sensitive elements using electronic means
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
- F23L13/00—Construction of valves or dampers for controlling air supply or draught
- F23L13/06—Construction of valves or dampers for controlling air supply or draught slidable only
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
- F23N5/02—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2225/00—Measuring
- F23N2225/08—Measuring temperature
- F23N2225/10—Measuring temperature stack temperature
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2235/00—Valves, nozzles or pumps
- F23N2235/02—Air or combustion gas valves or dampers
- F23N2235/06—Air or combustion gas valves or dampers at the air intake
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Control Of Combustion (AREA)
- Regulation And Control Of Combustion (AREA)
Abstract
The present invention relates to a system and method for controlling a burner's adjustable secondary air controller. Specifically, the system relates to a control logic for the control of an air supply to a burner such as a natural gas burner used in th e production and/or processing of liquid and gaseous petroleum products and in natural gas dehydration systems.
Description
PATENT APPLICATION
CONTROL OF AN ADJUSTABLE SECONDARY AIR CONTROLLER
FOR A BURNER
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is related to U.S. Patent Application No. 11/064,253, titled "Control of an Adjustable Secondary Air Controller for a Bumer", filed February 22, 2005.
BACKGROUND OF THE INVENTION
Field of the Invention (Technical Field):
The present invention relates to a system and method for controlling a bumer's adjustable secondary air controller. Specifically, the system relates to a control logic for the control of an air supply to a bumer such as a natural gas burner used in the production and/or processing of liquid and gaseous petroleum products and in natural gas dehydration systems.
Background Art:
Burners are used for various applications such as, for example, the production and/or processing of liquid and gaseous petroleum products. However, the typical burner with no variable air controller utilizes an excessive amount of air and oxygen, and such use is inefficient and wasteful since that excessive, unnecessary air is heated.
To increase efficiency, the variable air controller described in U.S. Patent No.
4,568,268, was directed to controlling the total air flowing into the burner housing as a function of the pressure of the natural gas supplied to the bumer. That air controller regulates the amount of air, and thus the desired 3% to 5% excess oxygen, and achieves a significant savings of fuel gas. In addition to allowing a primary supply of air which is always available, the secondary air controller controls the overall excess oxygen by controlling only a secondary air flow. Therefore, that air controller allows regulation of the air fuel ratio over the flring range for 3% to 5% of excess air.
However, the air controller of U.S. Patent No. 4,568,268 is prone to several problems.
When*the burner is at a low firing condition or completely off, many times low stack temperatures, as a result of reducing the air flow in the stack, resulted in stack sweating. Stack sweating was, at times, severe enough to cause water to flow back through the firetube and out of the breech of the flame arrestor. When the burner is off and the secondary air controller is closed, there is insufficient oxygen in the firetube to support firing of the main burners. When the process calls for heat, the main burners will begin firing before the secondary air controller can open creating a lack of oxygen and minor explosions in the firetube. The minor explosions are commonly referred to as "wolfing".
Also, the use of throttling thermostats, which are preferable in many applications, can create firing problems when the heat requirements for the process are low and the gas pressure to the burner is below the pressure required to create the gas velocity needed to properly draw and mix the primary air in the burner venture.
It is also difficult to adjust that air controller. Adjustment of the secondary air controller involves a trial and error changing of the compression springs which oppose the movement of the diaphragm on the secondary air controller. Differences in firetube size, altitude, gas composition, etc. requires adjustment of the secondary air controller. The adjustment entails firing the burner and analyzing the stack gases. If the stack gases do not meet the requirements, the burners are shut down, the compression springs are changed, the burner is relit, and the stack gases are again analyzed. The process of firing analyzing and changing compression springs is continued until the right composition of stack gases is obtained.
Getting the correct compressions springs installed has proven to be, at times, a long and difficult task.
CONTROL OF AN ADJUSTABLE SECONDARY AIR CONTROLLER
FOR A BURNER
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is related to U.S. Patent Application No. 11/064,253, titled "Control of an Adjustable Secondary Air Controller for a Bumer", filed February 22, 2005.
BACKGROUND OF THE INVENTION
Field of the Invention (Technical Field):
The present invention relates to a system and method for controlling a bumer's adjustable secondary air controller. Specifically, the system relates to a control logic for the control of an air supply to a bumer such as a natural gas burner used in the production and/or processing of liquid and gaseous petroleum products and in natural gas dehydration systems.
Background Art:
Burners are used for various applications such as, for example, the production and/or processing of liquid and gaseous petroleum products. However, the typical burner with no variable air controller utilizes an excessive amount of air and oxygen, and such use is inefficient and wasteful since that excessive, unnecessary air is heated.
To increase efficiency, the variable air controller described in U.S. Patent No.
4,568,268, was directed to controlling the total air flowing into the burner housing as a function of the pressure of the natural gas supplied to the bumer. That air controller regulates the amount of air, and thus the desired 3% to 5% excess oxygen, and achieves a significant savings of fuel gas. In addition to allowing a primary supply of air which is always available, the secondary air controller controls the overall excess oxygen by controlling only a secondary air flow. Therefore, that air controller allows regulation of the air fuel ratio over the flring range for 3% to 5% of excess air.
However, the air controller of U.S. Patent No. 4,568,268 is prone to several problems.
When*the burner is at a low firing condition or completely off, many times low stack temperatures, as a result of reducing the air flow in the stack, resulted in stack sweating. Stack sweating was, at times, severe enough to cause water to flow back through the firetube and out of the breech of the flame arrestor. When the burner is off and the secondary air controller is closed, there is insufficient oxygen in the firetube to support firing of the main burners. When the process calls for heat, the main burners will begin firing before the secondary air controller can open creating a lack of oxygen and minor explosions in the firetube. The minor explosions are commonly referred to as "wolfing".
Also, the use of throttling thermostats, which are preferable in many applications, can create firing problems when the heat requirements for the process are low and the gas pressure to the burner is below the pressure required to create the gas velocity needed to properly draw and mix the primary air in the burner venture.
It is also difficult to adjust that air controller. Adjustment of the secondary air controller involves a trial and error changing of the compression springs which oppose the movement of the diaphragm on the secondary air controller. Differences in firetube size, altitude, gas composition, etc. requires adjustment of the secondary air controller. The adjustment entails firing the burner and analyzing the stack gases. If the stack gases do not meet the requirements, the burners are shut down, the compression springs are changed, the burner is relit, and the stack gases are again analyzed. The process of firing analyzing and changing compression springs is continued until the right composition of stack gases is obtained.
Getting the correct compressions springs installed has proven to be, at times, a long and difficult task.
BRIEF SUMMARY OF THE INVENTION
The present invention provides a system for controlling a secondary air controller of a heating apparatus comprising a control logic for controlling flow of fuel to the heating apparatus and controlling the opening of a valve of the secondary air controller. An embodiment of the control logic preferably comprises a plurality of lines for communicating signals, a plurality of relays connected to the lines, and at least one controller to send a pressure signal to the relays, and the relays activate the flow of fuel and the opening of a valve of the secondary air controller.
The control logic preferably further comprises a permission start control linking at least one fuel valve and at least one relay. The system preferably comprises a stack temperature control linked to the valve of the secondary air controller. The system preferably comprises a biasing relay providing adjustment to regulate pressure to a diaphragm of the secondary air controller. The system preferably comprises a trimming air control valve to control introduction of air into a fire tube of the heating apparatus. The trimming air control valve is preferably linked to an accumulator and responds to an increase in pressure within the accumulator.
The present invention also provides a system for controlling a secondary air controller of a heating apparatus comprising a control logic for controlling flow of fuel to the heating apparatus and controlling the opening of a valve of the secondary air controller, said control logic comprising a plurality of lines for communicating signals, a plurality of relays connected to the lines to activate the flow of fuel, at least one controller to send a pressure signal to the relays, a temperature control valve in communication with the controller(s) to receive a pressure signal from the controller(s), and a biasing relay in communication with the temperature control valve to vent pressure on the secondary air controller and control the opening of a valve of the secondary air controller.
The present invention provides a system for controlling a secondary air controller of a heating apparatus comprising a control logic for controlling flow of fuel to the heating apparatus and controlling the opening of a valve of the secondary air controller. An embodiment of the control logic preferably comprises a plurality of lines for communicating signals, a plurality of relays connected to the lines, and at least one controller to send a pressure signal to the relays, and the relays activate the flow of fuel and the opening of a valve of the secondary air controller.
The control logic preferably further comprises a permission start control linking at least one fuel valve and at least one relay. The system preferably comprises a stack temperature control linked to the valve of the secondary air controller. The system preferably comprises a biasing relay providing adjustment to regulate pressure to a diaphragm of the secondary air controller. The system preferably comprises a trimming air control valve to control introduction of air into a fire tube of the heating apparatus. The trimming air control valve is preferably linked to an accumulator and responds to an increase in pressure within the accumulator.
The present invention also provides a system for controlling a secondary air controller of a heating apparatus comprising a control logic for controlling flow of fuel to the heating apparatus and controlling the opening of a valve of the secondary air controller, said control logic comprising a plurality of lines for communicating signals, a plurality of relays connected to the lines to activate the flow of fuel, at least one controller to send a pressure signal to the relays, a temperature control valve in communication with the controller(s) to receive a pressure signal from the controller(s), and a biasing relay in communication with the temperature control valve to vent pressure on the secondary air controller and control the opening of a valve of the secondary air controller.
The present invention also provides a method for controlling a secondary air controller of a heating apparatus comprising the steps of controlling flow of fuel to the heating apparatus via a control logic and controlling opening of a valve of the secondary air controller via the control logic. The method also comprises the control logic communicating signals via a plurality of lines, connecting a plurality of relays to the lines, controlling the flow of fuel and the opening of a valve of the secondary air controller via the relays and the lines, and sending a pressure signal to the relays via at least one controller.
The method further comprises providing a permission start control and linking at least one fuel valve and at least one relay with the permission to start control.
The method also preferably comprises providing a stack temperature control, and linking the stack temperature control to the valve of the secondary air controller. The method preferably comprises adjusting and regulating pressure to a diaphragm of the secondary air controller via a biasing relay.
The method preferably comprises providing a trimming air control valve and controlling introduction of air into a fire tube of the heating apparatus. Preferably, the method comprises linking an accumulator to the trimming air control valve and sending a pressure signal from the accumulator to the trimming air control valve.
The invention also provides a method for controlling a secondary air controller of a heating apparatus via a control logic to control a flow of fuel to the heating apparatus and to control opening of a valve of the secondary air controller, said method comprising communicating signals via a plurality of lines, connecting a plurality of relays to the lines, controlling the flow of fuel via the relays and the lines, sending a pressure signal to the relays via at least one controller, sending a pressure signal to a temperature control valve via the at least one controller, sending a pressure signal to a biasing relay via the temperature control valve, and venting pressure on the secondary air controller via the biasing relay to control the opening of a valve of the secondary air controller.
The method further comprises providing a permission start control and linking at least one fuel valve and at least one relay with the permission to start control.
The method also preferably comprises providing a stack temperature control, and linking the stack temperature control to the valve of the secondary air controller. The method preferably comprises adjusting and regulating pressure to a diaphragm of the secondary air controller via a biasing relay.
The method preferably comprises providing a trimming air control valve and controlling introduction of air into a fire tube of the heating apparatus. Preferably, the method comprises linking an accumulator to the trimming air control valve and sending a pressure signal from the accumulator to the trimming air control valve.
The invention also provides a method for controlling a secondary air controller of a heating apparatus via a control logic to control a flow of fuel to the heating apparatus and to control opening of a valve of the secondary air controller, said method comprising communicating signals via a plurality of lines, connecting a plurality of relays to the lines, controlling the flow of fuel via the relays and the lines, sending a pressure signal to the relays via at least one controller, sending a pressure signal to a temperature control valve via the at least one controller, sending a pressure signal to a biasing relay via the temperature control valve, and venting pressure on the secondary air controller via the biasing relay to control the opening of a valve of the secondary air controller.
A primary object of the present invention is to overcome the problem of stack sweating, lack of oxygen when the burner comes on, and low firing pressure.
A primary advantage of the present invention is that it allows for easy and quick adjustment to the secondary air controller.
Another advantage of the present invention is that it allows for the use of a secondary air controller in a burner utilized in a natural gas dehydration system.
Other objects, advantages and novel features, and further scope of applicability of the present invention are set forth in part in the detailed description to follow, taken in conjunction with the accompanying drawings, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
The accompanying drawings, which are incorporated into and form a part of the specification, illustrate one or more embodiments of the present invention and, together with the description, serve to explain the principles of the invention. The drawings are only for the purpose of illustrating one or more preferred embodiments of the invention and are not to be construed as limiting the invention. In the drawings:
Fig. 1 is an elevational, schematic view of a typical burner heating system described in U.S. Patent No. 4,568,268;
Fig. 2 is a cross-sectional view taken along the line 2--2 of Fig. 1;
Fig. 3 is an enlarged, cross-sectional view of the variable air controller of U.S. Patent No. 4,568,268;
Fig. 4 is a schematic of a control logic of an embodiment of the present invention;
A primary advantage of the present invention is that it allows for easy and quick adjustment to the secondary air controller.
Another advantage of the present invention is that it allows for the use of a secondary air controller in a burner utilized in a natural gas dehydration system.
Other objects, advantages and novel features, and further scope of applicability of the present invention are set forth in part in the detailed description to follow, taken in conjunction with the accompanying drawings, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
The accompanying drawings, which are incorporated into and form a part of the specification, illustrate one or more embodiments of the present invention and, together with the description, serve to explain the principles of the invention. The drawings are only for the purpose of illustrating one or more preferred embodiments of the invention and are not to be construed as limiting the invention. In the drawings:
Fig. 1 is an elevational, schematic view of a typical burner heating system described in U.S. Patent No. 4,568,268;
Fig. 2 is a cross-sectional view taken along the line 2--2 of Fig. 1;
Fig. 3 is an enlarged, cross-sectional view of the variable air controller of U.S. Patent No. 4,568,268;
Fig. 4 is a schematic of a control logic of an embodiment of the present invention;
Fig. 5 is an enlarged cross-sectional view of a mechanically adjustable embodiment of a variable air controller of the present invention; and Fig. 6 is a schematic of a control logic of an embodiment of the present invention wherein an air control valve responds to a biasing relay.
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention provides a system and method for controlling a burner's adjustable secondary air controller. Specifically, the system comprises a control. The present invention may be used in any burner wherein the control of an air supply to the burner as described herein is desired. Such burners include, but are not limited to, natural gas burners used in the production and/or processing of liquid and gaseous petroleum products.
As used herein, the terms "a", "an", and "the" mean one or more.
A non-limiting embodiment of the invention comprises a control logic to: (1) ensure that the burner gas supply closes when the burner gas pressure lowers to a predetermined pressure and does not open again until the burner gas supply pressure rises above the predetermined pressure or higher; (2) ensure that the air controller is open before the main burners begin firing; and (3) prevent stack temperatures from getting low enough to create stack sweating.
While the present invention may be used in connection with a burner in various types of uses, for purposes of illustration only the following discussion incorporates the burner and air controller described in U.S. Patent No. 4,568,268.
Referring to Fig. 1, the invention of U.S. Patent No. 4,568,268 is directed to a heating apparatus such as burner 110 comprising a housing 120 with atmospheric air inlet 122, preferably including a flame arrestor 124, which is covered by a hood 126 for keeping out debris and/or snow. Baffle 130 in housing 120 separates housing 120 into primary air inlet chamber 132 and combustion chamber 134. Main burner 136 and pilot burner 138 extend through baffle 130. Main burner 136 and pilot bumer 138 each includes a metering device such as venturis 140 and 142 for mixing air and fuel and metering devices 140 and 142 are positioned in primary air inlet chamber 132. Main burner 136 and pilot burner 138 each includes burner tips 144 and 146 which are positioned in combustion chamber 134. Therefore, primary air enters combustion chamber 134 and is mixed with the fuel by the metering devices and provides a flame at main burner 136 and pilot burner 138. In addition, adjustable secondary air controller 170 is provided for controlling secondary air so as to optimize the air fuel ratio. Secondary air controller 170 comprises valve 172 positioned between ambient air and combustion chamber 134, and a fuel pressure responsive means such as diaphragm 196 is connected to valve 172 for controlling the amount of secondary air in response to fuel pressure.
Fuel gas is supplied to the main burner venturi 140 by line 148 from on-off valve 150 from motor valve 149. Motor valve 149 automatically regulates the flow of gas to main burner 138 in response to the control of a pneumatic thermostat 152 from a line 154.
Gas supply pressure is supplied to thermostat 152 through line 156 which also supplied to burners 136 and 138. Gas for pilot burner 138 is supplied by line 158 through manual on-off valve 160 provided to allow shut-down of pilot 138 when the system is not in operation or to control the gas when pilot 138 is being lighted. Thermostat 152 and motor valve main burner valve 149 may be of either the on-off (snap) type or the throttling type.
Referring to Fig. 2, to regulate the air fuel ratio over the firing range of the burner between 3% to 5% of excess oxygen, secondary air is supplied to combustion chamber 134 through variable air controller 170. Variable air controller 170 is positioned between ambient air and combustion chamber 134 of the burner and is preferably positioned between primary inlet air chamber 132 and the combustion chamber 134 although air controller 170 may receive air in other ways. Air controller 170 includes valve element 172 which is connected to any suitable fuel pressure responsive means 174 for controlling the amount of secondary air supplied to combustion chamber 134 in response to the fuel pressure. Thus, pressure responsive means 174 may be connected to line 176 which in turn is connected to fuel line 148.
Air controller 170 of U.S Patent No. 4,568,268 is shown in more detail in Fig.
3. Air controller 170 automatically adjusts and controls the secondary supply of air flow to achieve the desired excess oxygen amount. Air controller 170 includes body 180 comprising variable size opening 182. Body 180 includes wall 181 which increases in size from a first end 184 to a second end 186 and is preferably tapered. Valve 172, such as a circular plate, is movable in opening 182 for changing the area of gap 183 between wall 181 and the outer edge of plate 172. Preferably, there is an air bypass in plate 172, such as leaving a minimum area open in gap 183, at all times which provides a minimum amount of air flow through air controller 170.
Plate 172 is mounted on a movable rod 188 which is slidable through well 189 of body 180 and secured to wall 190. Suitable biasing means such as one or more springs 192 and 194 are provided between walls 189 and 190 for yieldably urging plate 172 in a direction for reducing the volume of air flow through opening 182. Pressure responsive means, such as a diaphragm 196, is provided in housing 189 and on wall 190 and connected to valve 172 for moving valve 172 in a direction for increasing the volume of air in response to an increase in the pressure of the fuel. Diaphragm 196 is exposed to a port 198 which is connected to line 176. Therefore, increased pressure fuel acts on diaphragm 196 to move valve 182 towards second end 186 of tapered body 180 for increasing the annular area and increasing the volume of air. The area of valve opening 182 is varied approximately linearly with the pressurized fuel gas.
Additional secondary air for pilot burner 146 enters combustion chamber 134 through opening 164. Adjustment plate 162 provides a minimum area of opening consistent with stable burning of pilot burner 146 and to provide good lighting of the fuel air mixture at main burner tip 144 when main burner 136 is turned on.
When main burner 136 is turned on, additional secondary air is now required for complete combustion and to achieve the desired 3% to 5% excess oxygen.
Therefore, valve element 172 in air controller 170 opens and closes in proportion to the fuel gas pressure supplied to main burner 136 to achieve this desired result.
Referring to Fig. 4, control logic 200 of an embodiment of the present invention overcomes the problems of sweating, lack of oxygen when the burner comes on, and low firing pressure. Control logic 200 also preferably provides for adjustment of secondary air controller 170. Control logic 200 preferably comprises control pane1220. Preferably, lines for communicating pressure signals, such as, but not limited to, lines 301-327, are provided which form connections between relays and other components of the system.
Preferably, pressure gauges, 11-18, are also provided and disposed along lines 301-327. Ihstrument air or gas source 88 may be utilized to provide air or gas to control logic 200. If source 88 is utilized, control panel 220 is preferably vented to a safe location (not shown).
In an embodiment, control panel 220 comprises a permission to start control feature 83.
Control panel 220 preferably comprises at least one alarm 82 that informs an operator of any type of failure in the burner firing system (e.g., that the pilot light is no longer burning). When control panel 220 senses some type of alarm condition in the firing system, control panel 220 preferably shuts the firing system down until the problem or problems causing activation of alarm 82 have been corrected, and a permission to start signal has been sent to burner 110 and/or control logic 200. For example, once the pilot light (not shown) is relit, the operator can clear the alarm but the burner system will not restart until a permission to start signal has been sent to burner 110 and/or control logic 200.
Alarm 82 preferably vents the pressure signal shown as permission to start and causes valve 48 to close thereby stopping the flow of fuel to the burner and causing three-way pressure relay 50 to shift thereby venting the supply pressure so temperature control valve 46 cannot open. Also, normally opened pressure relay 62 is opened sending a pressure signal to fully open secondary air control valve 172 (shown in Fig. 3). Opening air control valve 172 purges fire tube 114 (shown in Fig. 1) and establishes conditions where the pilot light (not shown) can be safely relit.
In an embodiment, during cold start, air control valve 172 will preferably be wide open as throttling thermostat stack low temperature control 32 is cold and outputting a maximum signal of preferably between approximately 20 and 25 psig to relay 34. Relay 34 preferably communicates from thermostat stack low temperature control 32 to air control valve 172 via ports 36 and 38.
Process temperature controller 20 may be of any type known in the art and may include, but is not limited to, a throttling thermostat. When temperature controller 20 requests heat, output from temperature controller 20 at a signal of preferably between approximately 20 and 25 psig preferably goes to the diaphragm (not shown) of relay 40 which is adjusted to communicate ports 42 and 44 when the pressure on burner manifold 80 is greater than the minimum burner firing pressure. The firing pressure is preferably indicated by bumer fuel manifold gauge 47 preferably located downstream of temperature control valve 46. Relay 40, and other relays described herein, may be of any type known in the art capable of communicating pressure signals and may include, but are not limited to, snap acting switches.
Assuming that burners 136 and 138 (shown in Fig. 1) have a permission to start, valve 48 is preferably open and ports 52 and 54 of snap acting, start permission relay 50 are in communication. Output from snap acting relay 40 preferably activates time delay relay 56, which preferably comprises valve 58 and reservoir 60 through open ports 52 and 54 of start permission relay 50.
Time delay relay 56 preferably allows purging of combustion chamber 134 prior to introduction of fuel to burners 136 and 138. The length of the purge time may be altered by adjustment of valve 58. Valve 58 also preferably comprises an orifice check valve to rapidly vent the lines downstream of valve 58 when start permission relay 50 is vented.
When time delay relay 56 times out, pressure from start permission relay 50 will preferably close relay 62 and activate relay 64 to allow pressure to the diaphragm (not shown) of temperature control valve 46. Fuel will then flow to burners 136 and 138.
Because secondary air controller valve 172 is preferably fully open, there is adequate oxygen to support combustion without "wolfing".
Thermostat stack low temperature control 32 will preferably remain in control of air control valve 172 until thermostat stack low temperature control 32 is satisfied and relay 34 preferably switches ports to allow fuel manifold pressure to control air control valve 172 through bias relay 68. Bias relay 68 is preferably adjusted to compensate for fuel conditions including, but not limited to, heat content, site altitude, and stack draft.
'The adjustment will preferably regulate pressure to air control valve diaphragm 196 (shown in Fig.
3) to provide excess oxygen in the stack exhaust of 2 to 5% across the entire firing range.
Without changing the design of the air control valve 172, biasing relay 68 can be used to overcome the problem of adjusting air control valve 172 to allow for different operating conditions such as altitude, gas composition, stack height, etc. Biasing relay 68 is an apparatus that either increases or decreases a pressure signal and the magnitude of the increase or decrease in the pressure signal can be adjusted. Once the magnitude of the pressure increase or decrease has been set, the magnitude stays fixed until it is manually changed. For example, a burner unit that is firing without enough excess air indicates that springs 192 and 194, which resist the opening of air control valve opening 172, are exerting too great a force against the force created by diaphragm 196 of air control valve 172. The volume of secondary air flowing to burner 110 can be increased by adjusting biasing relay 68 to increase the pressure signal to diaphragm 196 of air control valve 172 thereby increasing the force exerted by diaphragm 196 against the force created by springs 192 and 194 further opening air control valve 172. The magnitude of the increase in force generated by diaphragm 196 would then remain constant throughout the firing pressure range of burner 110.
Referring to Fig. 4, the diaphragm (not shown) of biasing relay 68 is preferably connected to line 10 that supplies fuel to burner 110. Preferably, at all times biasing relay 68 is sensing the fuel pressure going to burner 110. If the amount of secondary air going to burner 110 must be increased or decreased, biasing relay 68 can be adjusted to change the magnitude of the pressure signal going to diaphragm 196 of air control-valve 172 thereby either increasing or decreasing air control valve opening 182 in response to burner firing pressure.
Preferably, the embodiment provides for a "warm shutdown". Generally, as process temperature is satisfied (i.e., when the heat output of fire tube 114 exceeds the heat required by the process utilizing burner 110) burners 136 and 138 are turned off at a preset minimum pressure to avoid pressure fluctuations and noise from low fuel pressure to burners 136 and 138. When process temperature controller 20 is satisfied, output to relay 40 and relay 64 declines. When the declining fuel pressure in manifold 80 reaches 1 to 2 psig (or at whatever point burner firing inconsistency occurs), temperature control valve 46 preferably will close as pressure to the diaphragm (not shown) of relay 64 will vent via port 45 of relay 40 (via relay 50). In turn, pressure to the diaphragm (not shown) of temperature control valve 46 will preferably vent through port 63 of relay 64. Relay 62 then preferably returns to its normally open position.
Air control valve 172 then preferably returns to its normally closed position -slightly open at the zero position. For all practical purposes, air flow through idle combustion chamber 134 is now blocked.
Following warm shutdown, startup from idle mode (burners off, process warm) preferably proceeds as follows. As process temperature controller 20 requests heat, output from temperature controller 20 goes to the diaphragm (not shown) of relay 40 which is adjusted to communicate ports 42 and 44 when the pressure on burner manifolq 80 is greater than the minimum burner firing pressure. Firing pressure is indicated by burner fuel manifold gauge 47 located downstream of temperature control valve 46.
Assuming that the burners have a permission to start, valve 48 is preferably open and ports 52 and 54 of start permission relay 50 are preferably in communication.
Output from relay 40 preferably activates time delay relay 56 through open ports 52 and 54 of start permission relay 50.
Time delay relay 56 preferably allows purging of the combustion chamber prior to introduction of fuel to the bumers. The length of the purge time may be altered by adjustment of valve 58.
When time delay relay 56 times out, pressure from start permission relay 50 will preferably close relay 62 and preferably activate relay 64 to allow pressure to the diaphragm (not shown) of temperature control valve 46. Fuel will then flow to the burners.
Air control valve 172 then preferably responds to pressure via relay 62 and relay 66, to put fully open air control valve 172 into purge mode in anticipation of burner ignition. As time delay relay 56 times out, the process preferably reverts to normal operation through bias relay 68.
The preferred embodiment of the present invention also prevents stack 31 from sweating during long idle periods. If the bumer system is idle (i.e., no heat is required by the process), and low stack temperature is detected, thermostat stack low temperature control 32 preferably outputs pressure to relay 34 and air control valve 172 will preferably open in : ... ...... . .... . ..:X' response to thermostat stack low temperature control 32. Wide open air control valve 172 will allow air flow to warm stack 31 to prevent sweating by removing heat from the process until process temperature controller 20 detects low process temperatures and begins controlling to initiate the cold start sequence described above.
The preferred embodiment of the present invention also preferably provides for emergency shutdown and restart of burner 110. If burner shutdown valve 48 activates, fuel to the burners is interrupted and start permission relay 50 will close and vent the signal to time delay relay 56 and the diaphragms (not shown) of relay 64 and relay 62. Loss of a permission signal will preferably close temperature control valve 46. Pressure flows to air control valve 172 via relay 62 and relay 66. This pressure preferably drives air control valve 172 to full open position and initiates purging of combustion chamber 34. When the problem causing the shutdown is rectified, burner shutdown valve 48 and start permission relay 50 will preferably reopen and startup will commence for cold startup or startup from idle as described above, depending on the temperature of stack 31 at the time of startup.
In some applications involving a natural gas dehydrator, the volume of gas recovered by the dehydration process will be insufficient to provide all the fuel required for a reboiler, but in other cases the volume of gas recovered by the process will exceed 60% or more of the fuel required for the reboiler. Utilizing a secondary air controller 170 on a natural gas dehydrator can increase firing efficiency of the reboiler to such an extent that the volume of gas recovered by the process exceeds the volume of fuel required to fire the reboiler, and the excess volume of recovered gas must then be used for other applications or else vented.
Therefore, to control the efficiency in combustion chamber 134 so that excess fuel recovered is completely consumed, trimming air control valve 70 is preferably provided as shown in Fig. 4.
Preferably, trimming air control valve is disposed on the same baffle 130 that holds the other air control valves and trimming air control valve 70 is preferably of the same design as the other air control valves. However, the pressure signal to the diaphragm (not shown) of trimming air control valve 70 is supplied by biasing relay; 74 rather than by biasing relay 68 which sends the pressure signals to the other air control valves located on the baffle.
Typically, on a natural gas dehydrator, the gas recovery system is designed to operate at between approximately 15 and 28 psig. As long as the volume of gas recovered by natural gas dehydration process does not exceed the volume of gas required to fire burner 110, the pressure in the recovered gas system will remain at the set pressure (e.g., between approximately 15 and 18 psig) for make-up fuel to begin feeding into the fuel system. If the installation of air controller 172 causes the volume of gas recovered by the natural gas dehydration process to exceed the volume of gas required to fire burner 110, pressure will begin to rise in the recovered gas system. If the volume of recovered gas is enough to fire bumer 110 and still cause the pressure in the recovered gas system to rise to, for example, approximately 28 psig, excess gas will be vented.
To prevent the pressure in the recovered gas system from reaching 28 psig, excess fuel is preferably accumulated in accumulator 72 comprising a reservoir such as, for example, a pressure tank. The normal operating pressure of accumulator 72 is preferably approximately 15 psig.
Preferably, in operation, there is a signal to the diaphragm (not shown) of biasing relay 74 or other type adjustable, throttling pressure pilot coming from accumulator 72. At a set point of preferably between approximately 18 and 23 psig, more preferably between approximately 18 and 20 psig pressure in accumulator 72, biasing relay 74 preferably sends a pressure signal to multiplying relay 76. Multiplying relay 76 preferably sends a pressure signal to the diaphragm (not shown) of trimming air control valve 70 thereby opening trimming air control valve 70. Multiplying relay 76 preferably multiplies the signal output of biasing relay 74 by as much as six times or as necessary to provide adequate pressure to open trimming air control valve 70. As trimming air control valve 70 opens, additional air is admitted into fire tube 114 thereby decreasing firing efficiency and causing burner 110 to begin consuming the accumulated fuel. Opening trimming air control valve 70 introduces excess secondary air into fire tube 114 thereby decreasing firing efficiency and causing burner 110 to begin consuming more fuel. Preferably, multiplying relay 76 amplifies pressure from accumulator 72 above the set point pressure to obtain a quick response of trimming air control valve 70. Preferably, the pressure rise in accumulator 72 is limited to from between approximately 1 and 5 psi above the set point.
When the excess fuel in accumulator 72 is consumed and the pressure in accumulator 72 decreases to the set point (e.g., 18 psig) or less, biasing relay 74 and multiplying relay 76 preferably vent the pressure from the diaphragm (not shown) of trimming air control valve 70, and trimming air control valve 70 closes. When trimming air control valve 70 closes, air controller 170 returns to normal operation.
In another embodiment, shown in Fig. 5, the invention may comprise secondary air controller 90 that may be utilized in lieu of biasing relay 68 for adjustment purposes.
Secondary air controller 90 preferably comprises tension springs 91 that oppose the movement of diaphragm 92 on secondary air controller 90. This provides, without disassembly of the diaphragm case, for adjustment of the spring tension by simply rotating bolt 93 thus changing the force exerted against diaphragm 92. Bolt 93 is preferably connected to plate 94 which is preferably connected at the top to springs 91. Springs 91 are preferably connected at the bottom to plate 95. Plate 95 is preferably connected to resist the downward movement of diaphragm 92. Without disassembly or shutting off burner 110, the amount of secondary air induced into fire tube 114 can be adjusted, in a real time mode, by preferably turning bolt 93 either clock wise or counter-clock wise to decrease or increase the tension in springs 91.
Another embodiment of the present invention is applicable for use on smaller dehydrators, heaters, and other production equipment where utilization of all features described above may not be economically warranted, but where significant fuel savings may be realized.
_,....: .. ... . sx The majority of firetube applications in the oil and gas industry are typically small wellhead separators, treaters, dehydrators, and heaters. Most of this equipment requires smaller amounts of heat for the process - generally less than 500,000 BTU per hour and frequently less than 100,000 BTU per hour. For these smaller applications, a full adjustable secondary air controller system, as described above, may be considered to be too complicated and/or too expensive. But because such a system may still provide for more economical processing of gas, the following described embodiment is applicable.
Thus, the following embodiment preferably addresses only the issues of fuel economy, stack sweating during low firing and off periods, and adjustment for fuel content, altitude, and stack draft. In this embodiment, the adjustable secondary air controller housing, burner, pilot and air control valve are constructed in a fashion similar to that shown in Fig. 1. However, the air control valve will respond to the an output from a biasing relay and low temperature thermostat as described below and as shown in Fig. 6.
Referring to Fig. 6, control logic 400 overcomes the problems of sweating and provides for adjustment of secondary air controller 172 (shown in Fig. 3). Preferably, lines for communicating pressure signals, such as, but not limited to, lines 401 - 410, are provided which form connections between relays and other components of the system.
Preferably, pressure gauges, 411- 414, are also provided and disposed along lines 401-410. Instrument air or gas source 419 may be utilized to provide air or gas to control logic 400.
Control logic 400 may comprise at least one alarm 420 that senses a problem with the burner or the process (for example, that the pilot light is no longer burning), and interrupts the control signal to temperature control valve 415 which shuts the firing system down until the problem or problems causing activation of the alarm(s) have been corrected.
For example, once the pilot light (not shown) is relit, the operator can clear the alarm and the adjustable secondary air controller / burner system will restart.
Alarm 420 preferably vents the pressure signal through line 401 and causes valve 415 to close thereby stopping the flow of fuel to the burner and returning air control valve 172 (shown in Fig. 3) to its idle position. At idle position, air controi valve 172 is slightly open to allow enough air flow to permit the pilot light (not shown) to be safely relit.
Preferably, during cold start, air control valve 172 will be wide open as throttling thermostat stack low temperature control 417 is cold and outputting a maximum signal of preferably between approximately 20 and 25 psig to relay 418. Relay 418 communicates from thermostat stack low temperature control 417 to air control valve 172 via ports 422 and 423.
Relay 418, and other relays described herein, may be of any type known in the art capable of communicating pressure signals and may include, but are not limited to, snap acting switches.
I
Process temperature controller 20 (previously described) may be of any type known in the art and may include, but is not limited to, a throttling thermostat.
Assuming the pilot is established and alarm(s) 420 is in a permissive position, when temperature controller 20 requests heat, output from temperature controller 20 at a signal of preferably between approximately 20 and 25 psig goes to the diaphragm (not shown) of valve 415 via line 401 to permit pressure on bumer manifold 404. The firing pressure is indicated by bumer fuel manifold gauge 411 preferably located downstream of temperature control valve 415.
Assuming that burner 136 (shown in Fig. 1) has a permission to start via alarm(s) 420, valve 415 is open and fuel will flow to burner 136. Because secondary air controller valve 172 is fully open, there is adequate oxygen to support combustion without "wolfing".
Preferably, thermostat stack low temperature control 417 will remain in control of air control valve 172 until thermostat stack low temperature control 417 reaches its low set point (usually in the range of approximately 300 to 400 degrees F) and relay 418 switches ports to allow fuel manifold pressure to control air control valve 172 through bias relay 416. Preferably, bias relay 416 is adjusted to compensate for fuel conditions including, but not limited to, heat content, site altitude, and stack draft. The adjustment regulates pressure to air control valve diaphragm 196 (shown in Fig. 3) to provide excess oxygen in the stack exhaust of approximately 2 to 5% across the entire firing range.
Without changing the design of air control valve 172, biasing relay 416 can be used to overcome the problem of adjusting air control valve 172 to allow for different operating conditions such as altitude, gas composition, stack height, etc. Preferably biasing relay 416 is an apparatus that either increases or decreases a pressure signal, and the magnitude of the increase or decrease in the pressure signal can be adjusted. Once the magnitude of the pressure increase or decrease has been set, the magnitude stays fixed until it is manually changed. For example, a burner unit that is firing without enough excess air indicates that springs 192 and 194 (shown in Fig. 3), which resist the opening of air control valve opening 172, are exerting too great a force against the force created by diaphragm 196 of air control valve 172. The volume of secondary air flowing to burner 110 can be increased by adjusting biasing relay 416 to increase the pressure signal to diaphragm 196 of air control valve 172 thereby increasing the force exerted by diaphragm 196 against the force created by springs 192 and 194 further opening air control valve 172. The magnitude of the increase in force generated by diaphragm 196 would then remain constant throughout the firing pressure range of burner 110.
Referring to Fig. 6, the diaphragm (not shown) of biasing relay 416 is preferably connected to line 404 that supplies fuel to burner 110. Preferably, at all times, biasing relay 416 senses the fuel pressure going to burner 110. If the amount of secondary air going to burner 110 must be increased or decreased, biasing relay 416 can be adjusted to change the magnitude of the pressure signal going to diaphragm 196 of air control valve 172 thereby either increasing or decreasing air control valve opening 182 in response to burner firing pressure.
This embodiment provides for a "warm shutdown". Generally, as process temperature _ ....,-.. ___ .. .._x is satisfied (i.e., when the heat output of fire tube 114 exceeds the heat required by the process utilizing burner 110) burner 136 is turned off. When process temperature controller 20 is satisfied, output to alarm(s) 420 and temperature control valve 415 declines.
As the output pressure from the process temperature controller 20 declines, temperature control valve 415 will close, and biasing relay 416 will revert to its normal position and vent the pressure on the air control valve diaphragm 92 (shown in Fig. 5) via vent ports 424 and 425.
Air control valve 172 then returns to its normally closed position - slightly open at the zero position. For all practical purposes, air flow through idle combustion chamber 134 is now blocked.
Following warm shutdown, startup from idle mode (burners off, process warm) preferably proceeds as follows. As process temperature controller 20 requests heat, output from temperature controller 20 goes to alarm(s) 420 and to the temperature control valve 415.
Assuming that the burner has a permission to start, alarm(s) 420 is in a permissive mode, and the control signal from process temperature controller 20 is communicated to the diaphragm of temperature control valve 415. Fuel will then flow to the burner.
This embodiment also prevents stack 31 from sweating during long idle periods.
Preferably, if the burner system is idle (i.e., no heat is required by the process), and low stack temperature is detected, thermostat stack low temperature control 417 outputs pressure to relay 418, and air control valve 172 will open in response to thermostat stack low temperature control 417. Opening air control valve 172 allows air flow to warm stack 31 to prevent sweating by removing heat from the process until process temperature controller 20 detects low process temperatures and begins controlling to initiate the cold start sequence Oescribed above.
Preferably, this embodiment also provides for emergency shutdown and restart of burner 110. If alarm(s) 420 activates, temperature control valve 415 will close and fuel to the burner is interrupted, biasing relay 416 vents pressure from the air control valve diaphragm 92 (shown in Fig.5), and air control valve 172 returns to its idle position. When the problem causing the shutdown is rectified, alarm(s) 420 allows pressure to the diaphragm of temperature control valve 415 and startup will commence for cold startup or startup from idle as described above, depending on the temperature of stack 31 at the time of startup.
This embodiment is useable in concert with the trimming control valve as shown in Fig. 4 and whose function and design are described above. ' The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.
Although the invention has been described in detail with particular reference to the preferred embodiments in the attachment, other embodiments can achieve the same results.
Variations and modifications of the present invention will be obvious to those skilled in the art and it is intended to cover all such modifications and equivalents. The entire disclosures of all references, applications, patents, and publications cited above, and of the corresponding application(s), are hereby incorporated by reference.
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention provides a system and method for controlling a burner's adjustable secondary air controller. Specifically, the system comprises a control. The present invention may be used in any burner wherein the control of an air supply to the burner as described herein is desired. Such burners include, but are not limited to, natural gas burners used in the production and/or processing of liquid and gaseous petroleum products.
As used herein, the terms "a", "an", and "the" mean one or more.
A non-limiting embodiment of the invention comprises a control logic to: (1) ensure that the burner gas supply closes when the burner gas pressure lowers to a predetermined pressure and does not open again until the burner gas supply pressure rises above the predetermined pressure or higher; (2) ensure that the air controller is open before the main burners begin firing; and (3) prevent stack temperatures from getting low enough to create stack sweating.
While the present invention may be used in connection with a burner in various types of uses, for purposes of illustration only the following discussion incorporates the burner and air controller described in U.S. Patent No. 4,568,268.
Referring to Fig. 1, the invention of U.S. Patent No. 4,568,268 is directed to a heating apparatus such as burner 110 comprising a housing 120 with atmospheric air inlet 122, preferably including a flame arrestor 124, which is covered by a hood 126 for keeping out debris and/or snow. Baffle 130 in housing 120 separates housing 120 into primary air inlet chamber 132 and combustion chamber 134. Main burner 136 and pilot burner 138 extend through baffle 130. Main burner 136 and pilot bumer 138 each includes a metering device such as venturis 140 and 142 for mixing air and fuel and metering devices 140 and 142 are positioned in primary air inlet chamber 132. Main burner 136 and pilot burner 138 each includes burner tips 144 and 146 which are positioned in combustion chamber 134. Therefore, primary air enters combustion chamber 134 and is mixed with the fuel by the metering devices and provides a flame at main burner 136 and pilot burner 138. In addition, adjustable secondary air controller 170 is provided for controlling secondary air so as to optimize the air fuel ratio. Secondary air controller 170 comprises valve 172 positioned between ambient air and combustion chamber 134, and a fuel pressure responsive means such as diaphragm 196 is connected to valve 172 for controlling the amount of secondary air in response to fuel pressure.
Fuel gas is supplied to the main burner venturi 140 by line 148 from on-off valve 150 from motor valve 149. Motor valve 149 automatically regulates the flow of gas to main burner 138 in response to the control of a pneumatic thermostat 152 from a line 154.
Gas supply pressure is supplied to thermostat 152 through line 156 which also supplied to burners 136 and 138. Gas for pilot burner 138 is supplied by line 158 through manual on-off valve 160 provided to allow shut-down of pilot 138 when the system is not in operation or to control the gas when pilot 138 is being lighted. Thermostat 152 and motor valve main burner valve 149 may be of either the on-off (snap) type or the throttling type.
Referring to Fig. 2, to regulate the air fuel ratio over the firing range of the burner between 3% to 5% of excess oxygen, secondary air is supplied to combustion chamber 134 through variable air controller 170. Variable air controller 170 is positioned between ambient air and combustion chamber 134 of the burner and is preferably positioned between primary inlet air chamber 132 and the combustion chamber 134 although air controller 170 may receive air in other ways. Air controller 170 includes valve element 172 which is connected to any suitable fuel pressure responsive means 174 for controlling the amount of secondary air supplied to combustion chamber 134 in response to the fuel pressure. Thus, pressure responsive means 174 may be connected to line 176 which in turn is connected to fuel line 148.
Air controller 170 of U.S Patent No. 4,568,268 is shown in more detail in Fig.
3. Air controller 170 automatically adjusts and controls the secondary supply of air flow to achieve the desired excess oxygen amount. Air controller 170 includes body 180 comprising variable size opening 182. Body 180 includes wall 181 which increases in size from a first end 184 to a second end 186 and is preferably tapered. Valve 172, such as a circular plate, is movable in opening 182 for changing the area of gap 183 between wall 181 and the outer edge of plate 172. Preferably, there is an air bypass in plate 172, such as leaving a minimum area open in gap 183, at all times which provides a minimum amount of air flow through air controller 170.
Plate 172 is mounted on a movable rod 188 which is slidable through well 189 of body 180 and secured to wall 190. Suitable biasing means such as one or more springs 192 and 194 are provided between walls 189 and 190 for yieldably urging plate 172 in a direction for reducing the volume of air flow through opening 182. Pressure responsive means, such as a diaphragm 196, is provided in housing 189 and on wall 190 and connected to valve 172 for moving valve 172 in a direction for increasing the volume of air in response to an increase in the pressure of the fuel. Diaphragm 196 is exposed to a port 198 which is connected to line 176. Therefore, increased pressure fuel acts on diaphragm 196 to move valve 182 towards second end 186 of tapered body 180 for increasing the annular area and increasing the volume of air. The area of valve opening 182 is varied approximately linearly with the pressurized fuel gas.
Additional secondary air for pilot burner 146 enters combustion chamber 134 through opening 164. Adjustment plate 162 provides a minimum area of opening consistent with stable burning of pilot burner 146 and to provide good lighting of the fuel air mixture at main burner tip 144 when main burner 136 is turned on.
When main burner 136 is turned on, additional secondary air is now required for complete combustion and to achieve the desired 3% to 5% excess oxygen.
Therefore, valve element 172 in air controller 170 opens and closes in proportion to the fuel gas pressure supplied to main burner 136 to achieve this desired result.
Referring to Fig. 4, control logic 200 of an embodiment of the present invention overcomes the problems of sweating, lack of oxygen when the burner comes on, and low firing pressure. Control logic 200 also preferably provides for adjustment of secondary air controller 170. Control logic 200 preferably comprises control pane1220. Preferably, lines for communicating pressure signals, such as, but not limited to, lines 301-327, are provided which form connections between relays and other components of the system.
Preferably, pressure gauges, 11-18, are also provided and disposed along lines 301-327. Ihstrument air or gas source 88 may be utilized to provide air or gas to control logic 200. If source 88 is utilized, control panel 220 is preferably vented to a safe location (not shown).
In an embodiment, control panel 220 comprises a permission to start control feature 83.
Control panel 220 preferably comprises at least one alarm 82 that informs an operator of any type of failure in the burner firing system (e.g., that the pilot light is no longer burning). When control panel 220 senses some type of alarm condition in the firing system, control panel 220 preferably shuts the firing system down until the problem or problems causing activation of alarm 82 have been corrected, and a permission to start signal has been sent to burner 110 and/or control logic 200. For example, once the pilot light (not shown) is relit, the operator can clear the alarm but the burner system will not restart until a permission to start signal has been sent to burner 110 and/or control logic 200.
Alarm 82 preferably vents the pressure signal shown as permission to start and causes valve 48 to close thereby stopping the flow of fuel to the burner and causing three-way pressure relay 50 to shift thereby venting the supply pressure so temperature control valve 46 cannot open. Also, normally opened pressure relay 62 is opened sending a pressure signal to fully open secondary air control valve 172 (shown in Fig. 3). Opening air control valve 172 purges fire tube 114 (shown in Fig. 1) and establishes conditions where the pilot light (not shown) can be safely relit.
In an embodiment, during cold start, air control valve 172 will preferably be wide open as throttling thermostat stack low temperature control 32 is cold and outputting a maximum signal of preferably between approximately 20 and 25 psig to relay 34. Relay 34 preferably communicates from thermostat stack low temperature control 32 to air control valve 172 via ports 36 and 38.
Process temperature controller 20 may be of any type known in the art and may include, but is not limited to, a throttling thermostat. When temperature controller 20 requests heat, output from temperature controller 20 at a signal of preferably between approximately 20 and 25 psig preferably goes to the diaphragm (not shown) of relay 40 which is adjusted to communicate ports 42 and 44 when the pressure on burner manifold 80 is greater than the minimum burner firing pressure. The firing pressure is preferably indicated by bumer fuel manifold gauge 47 preferably located downstream of temperature control valve 46. Relay 40, and other relays described herein, may be of any type known in the art capable of communicating pressure signals and may include, but are not limited to, snap acting switches.
Assuming that burners 136 and 138 (shown in Fig. 1) have a permission to start, valve 48 is preferably open and ports 52 and 54 of snap acting, start permission relay 50 are in communication. Output from snap acting relay 40 preferably activates time delay relay 56, which preferably comprises valve 58 and reservoir 60 through open ports 52 and 54 of start permission relay 50.
Time delay relay 56 preferably allows purging of combustion chamber 134 prior to introduction of fuel to burners 136 and 138. The length of the purge time may be altered by adjustment of valve 58. Valve 58 also preferably comprises an orifice check valve to rapidly vent the lines downstream of valve 58 when start permission relay 50 is vented.
When time delay relay 56 times out, pressure from start permission relay 50 will preferably close relay 62 and activate relay 64 to allow pressure to the diaphragm (not shown) of temperature control valve 46. Fuel will then flow to burners 136 and 138.
Because secondary air controller valve 172 is preferably fully open, there is adequate oxygen to support combustion without "wolfing".
Thermostat stack low temperature control 32 will preferably remain in control of air control valve 172 until thermostat stack low temperature control 32 is satisfied and relay 34 preferably switches ports to allow fuel manifold pressure to control air control valve 172 through bias relay 68. Bias relay 68 is preferably adjusted to compensate for fuel conditions including, but not limited to, heat content, site altitude, and stack draft.
'The adjustment will preferably regulate pressure to air control valve diaphragm 196 (shown in Fig.
3) to provide excess oxygen in the stack exhaust of 2 to 5% across the entire firing range.
Without changing the design of the air control valve 172, biasing relay 68 can be used to overcome the problem of adjusting air control valve 172 to allow for different operating conditions such as altitude, gas composition, stack height, etc. Biasing relay 68 is an apparatus that either increases or decreases a pressure signal and the magnitude of the increase or decrease in the pressure signal can be adjusted. Once the magnitude of the pressure increase or decrease has been set, the magnitude stays fixed until it is manually changed. For example, a burner unit that is firing without enough excess air indicates that springs 192 and 194, which resist the opening of air control valve opening 172, are exerting too great a force against the force created by diaphragm 196 of air control valve 172. The volume of secondary air flowing to burner 110 can be increased by adjusting biasing relay 68 to increase the pressure signal to diaphragm 196 of air control valve 172 thereby increasing the force exerted by diaphragm 196 against the force created by springs 192 and 194 further opening air control valve 172. The magnitude of the increase in force generated by diaphragm 196 would then remain constant throughout the firing pressure range of burner 110.
Referring to Fig. 4, the diaphragm (not shown) of biasing relay 68 is preferably connected to line 10 that supplies fuel to burner 110. Preferably, at all times biasing relay 68 is sensing the fuel pressure going to burner 110. If the amount of secondary air going to burner 110 must be increased or decreased, biasing relay 68 can be adjusted to change the magnitude of the pressure signal going to diaphragm 196 of air control-valve 172 thereby either increasing or decreasing air control valve opening 182 in response to burner firing pressure.
Preferably, the embodiment provides for a "warm shutdown". Generally, as process temperature is satisfied (i.e., when the heat output of fire tube 114 exceeds the heat required by the process utilizing burner 110) burners 136 and 138 are turned off at a preset minimum pressure to avoid pressure fluctuations and noise from low fuel pressure to burners 136 and 138. When process temperature controller 20 is satisfied, output to relay 40 and relay 64 declines. When the declining fuel pressure in manifold 80 reaches 1 to 2 psig (or at whatever point burner firing inconsistency occurs), temperature control valve 46 preferably will close as pressure to the diaphragm (not shown) of relay 64 will vent via port 45 of relay 40 (via relay 50). In turn, pressure to the diaphragm (not shown) of temperature control valve 46 will preferably vent through port 63 of relay 64. Relay 62 then preferably returns to its normally open position.
Air control valve 172 then preferably returns to its normally closed position -slightly open at the zero position. For all practical purposes, air flow through idle combustion chamber 134 is now blocked.
Following warm shutdown, startup from idle mode (burners off, process warm) preferably proceeds as follows. As process temperature controller 20 requests heat, output from temperature controller 20 goes to the diaphragm (not shown) of relay 40 which is adjusted to communicate ports 42 and 44 when the pressure on burner manifolq 80 is greater than the minimum burner firing pressure. Firing pressure is indicated by burner fuel manifold gauge 47 located downstream of temperature control valve 46.
Assuming that the burners have a permission to start, valve 48 is preferably open and ports 52 and 54 of start permission relay 50 are preferably in communication.
Output from relay 40 preferably activates time delay relay 56 through open ports 52 and 54 of start permission relay 50.
Time delay relay 56 preferably allows purging of the combustion chamber prior to introduction of fuel to the bumers. The length of the purge time may be altered by adjustment of valve 58.
When time delay relay 56 times out, pressure from start permission relay 50 will preferably close relay 62 and preferably activate relay 64 to allow pressure to the diaphragm (not shown) of temperature control valve 46. Fuel will then flow to the burners.
Air control valve 172 then preferably responds to pressure via relay 62 and relay 66, to put fully open air control valve 172 into purge mode in anticipation of burner ignition. As time delay relay 56 times out, the process preferably reverts to normal operation through bias relay 68.
The preferred embodiment of the present invention also prevents stack 31 from sweating during long idle periods. If the bumer system is idle (i.e., no heat is required by the process), and low stack temperature is detected, thermostat stack low temperature control 32 preferably outputs pressure to relay 34 and air control valve 172 will preferably open in : ... ...... . .... . ..:X' response to thermostat stack low temperature control 32. Wide open air control valve 172 will allow air flow to warm stack 31 to prevent sweating by removing heat from the process until process temperature controller 20 detects low process temperatures and begins controlling to initiate the cold start sequence described above.
The preferred embodiment of the present invention also preferably provides for emergency shutdown and restart of burner 110. If burner shutdown valve 48 activates, fuel to the burners is interrupted and start permission relay 50 will close and vent the signal to time delay relay 56 and the diaphragms (not shown) of relay 64 and relay 62. Loss of a permission signal will preferably close temperature control valve 46. Pressure flows to air control valve 172 via relay 62 and relay 66. This pressure preferably drives air control valve 172 to full open position and initiates purging of combustion chamber 34. When the problem causing the shutdown is rectified, burner shutdown valve 48 and start permission relay 50 will preferably reopen and startup will commence for cold startup or startup from idle as described above, depending on the temperature of stack 31 at the time of startup.
In some applications involving a natural gas dehydrator, the volume of gas recovered by the dehydration process will be insufficient to provide all the fuel required for a reboiler, but in other cases the volume of gas recovered by the process will exceed 60% or more of the fuel required for the reboiler. Utilizing a secondary air controller 170 on a natural gas dehydrator can increase firing efficiency of the reboiler to such an extent that the volume of gas recovered by the process exceeds the volume of fuel required to fire the reboiler, and the excess volume of recovered gas must then be used for other applications or else vented.
Therefore, to control the efficiency in combustion chamber 134 so that excess fuel recovered is completely consumed, trimming air control valve 70 is preferably provided as shown in Fig. 4.
Preferably, trimming air control valve is disposed on the same baffle 130 that holds the other air control valves and trimming air control valve 70 is preferably of the same design as the other air control valves. However, the pressure signal to the diaphragm (not shown) of trimming air control valve 70 is supplied by biasing relay; 74 rather than by biasing relay 68 which sends the pressure signals to the other air control valves located on the baffle.
Typically, on a natural gas dehydrator, the gas recovery system is designed to operate at between approximately 15 and 28 psig. As long as the volume of gas recovered by natural gas dehydration process does not exceed the volume of gas required to fire burner 110, the pressure in the recovered gas system will remain at the set pressure (e.g., between approximately 15 and 18 psig) for make-up fuel to begin feeding into the fuel system. If the installation of air controller 172 causes the volume of gas recovered by the natural gas dehydration process to exceed the volume of gas required to fire burner 110, pressure will begin to rise in the recovered gas system. If the volume of recovered gas is enough to fire bumer 110 and still cause the pressure in the recovered gas system to rise to, for example, approximately 28 psig, excess gas will be vented.
To prevent the pressure in the recovered gas system from reaching 28 psig, excess fuel is preferably accumulated in accumulator 72 comprising a reservoir such as, for example, a pressure tank. The normal operating pressure of accumulator 72 is preferably approximately 15 psig.
Preferably, in operation, there is a signal to the diaphragm (not shown) of biasing relay 74 or other type adjustable, throttling pressure pilot coming from accumulator 72. At a set point of preferably between approximately 18 and 23 psig, more preferably between approximately 18 and 20 psig pressure in accumulator 72, biasing relay 74 preferably sends a pressure signal to multiplying relay 76. Multiplying relay 76 preferably sends a pressure signal to the diaphragm (not shown) of trimming air control valve 70 thereby opening trimming air control valve 70. Multiplying relay 76 preferably multiplies the signal output of biasing relay 74 by as much as six times or as necessary to provide adequate pressure to open trimming air control valve 70. As trimming air control valve 70 opens, additional air is admitted into fire tube 114 thereby decreasing firing efficiency and causing burner 110 to begin consuming the accumulated fuel. Opening trimming air control valve 70 introduces excess secondary air into fire tube 114 thereby decreasing firing efficiency and causing burner 110 to begin consuming more fuel. Preferably, multiplying relay 76 amplifies pressure from accumulator 72 above the set point pressure to obtain a quick response of trimming air control valve 70. Preferably, the pressure rise in accumulator 72 is limited to from between approximately 1 and 5 psi above the set point.
When the excess fuel in accumulator 72 is consumed and the pressure in accumulator 72 decreases to the set point (e.g., 18 psig) or less, biasing relay 74 and multiplying relay 76 preferably vent the pressure from the diaphragm (not shown) of trimming air control valve 70, and trimming air control valve 70 closes. When trimming air control valve 70 closes, air controller 170 returns to normal operation.
In another embodiment, shown in Fig. 5, the invention may comprise secondary air controller 90 that may be utilized in lieu of biasing relay 68 for adjustment purposes.
Secondary air controller 90 preferably comprises tension springs 91 that oppose the movement of diaphragm 92 on secondary air controller 90. This provides, without disassembly of the diaphragm case, for adjustment of the spring tension by simply rotating bolt 93 thus changing the force exerted against diaphragm 92. Bolt 93 is preferably connected to plate 94 which is preferably connected at the top to springs 91. Springs 91 are preferably connected at the bottom to plate 95. Plate 95 is preferably connected to resist the downward movement of diaphragm 92. Without disassembly or shutting off burner 110, the amount of secondary air induced into fire tube 114 can be adjusted, in a real time mode, by preferably turning bolt 93 either clock wise or counter-clock wise to decrease or increase the tension in springs 91.
Another embodiment of the present invention is applicable for use on smaller dehydrators, heaters, and other production equipment where utilization of all features described above may not be economically warranted, but where significant fuel savings may be realized.
_,....: .. ... . sx The majority of firetube applications in the oil and gas industry are typically small wellhead separators, treaters, dehydrators, and heaters. Most of this equipment requires smaller amounts of heat for the process - generally less than 500,000 BTU per hour and frequently less than 100,000 BTU per hour. For these smaller applications, a full adjustable secondary air controller system, as described above, may be considered to be too complicated and/or too expensive. But because such a system may still provide for more economical processing of gas, the following described embodiment is applicable.
Thus, the following embodiment preferably addresses only the issues of fuel economy, stack sweating during low firing and off periods, and adjustment for fuel content, altitude, and stack draft. In this embodiment, the adjustable secondary air controller housing, burner, pilot and air control valve are constructed in a fashion similar to that shown in Fig. 1. However, the air control valve will respond to the an output from a biasing relay and low temperature thermostat as described below and as shown in Fig. 6.
Referring to Fig. 6, control logic 400 overcomes the problems of sweating and provides for adjustment of secondary air controller 172 (shown in Fig. 3). Preferably, lines for communicating pressure signals, such as, but not limited to, lines 401 - 410, are provided which form connections between relays and other components of the system.
Preferably, pressure gauges, 411- 414, are also provided and disposed along lines 401-410. Instrument air or gas source 419 may be utilized to provide air or gas to control logic 400.
Control logic 400 may comprise at least one alarm 420 that senses a problem with the burner or the process (for example, that the pilot light is no longer burning), and interrupts the control signal to temperature control valve 415 which shuts the firing system down until the problem or problems causing activation of the alarm(s) have been corrected.
For example, once the pilot light (not shown) is relit, the operator can clear the alarm and the adjustable secondary air controller / burner system will restart.
Alarm 420 preferably vents the pressure signal through line 401 and causes valve 415 to close thereby stopping the flow of fuel to the burner and returning air control valve 172 (shown in Fig. 3) to its idle position. At idle position, air controi valve 172 is slightly open to allow enough air flow to permit the pilot light (not shown) to be safely relit.
Preferably, during cold start, air control valve 172 will be wide open as throttling thermostat stack low temperature control 417 is cold and outputting a maximum signal of preferably between approximately 20 and 25 psig to relay 418. Relay 418 communicates from thermostat stack low temperature control 417 to air control valve 172 via ports 422 and 423.
Relay 418, and other relays described herein, may be of any type known in the art capable of communicating pressure signals and may include, but are not limited to, snap acting switches.
I
Process temperature controller 20 (previously described) may be of any type known in the art and may include, but is not limited to, a throttling thermostat.
Assuming the pilot is established and alarm(s) 420 is in a permissive position, when temperature controller 20 requests heat, output from temperature controller 20 at a signal of preferably between approximately 20 and 25 psig goes to the diaphragm (not shown) of valve 415 via line 401 to permit pressure on bumer manifold 404. The firing pressure is indicated by bumer fuel manifold gauge 411 preferably located downstream of temperature control valve 415.
Assuming that burner 136 (shown in Fig. 1) has a permission to start via alarm(s) 420, valve 415 is open and fuel will flow to burner 136. Because secondary air controller valve 172 is fully open, there is adequate oxygen to support combustion without "wolfing".
Preferably, thermostat stack low temperature control 417 will remain in control of air control valve 172 until thermostat stack low temperature control 417 reaches its low set point (usually in the range of approximately 300 to 400 degrees F) and relay 418 switches ports to allow fuel manifold pressure to control air control valve 172 through bias relay 416. Preferably, bias relay 416 is adjusted to compensate for fuel conditions including, but not limited to, heat content, site altitude, and stack draft. The adjustment regulates pressure to air control valve diaphragm 196 (shown in Fig. 3) to provide excess oxygen in the stack exhaust of approximately 2 to 5% across the entire firing range.
Without changing the design of air control valve 172, biasing relay 416 can be used to overcome the problem of adjusting air control valve 172 to allow for different operating conditions such as altitude, gas composition, stack height, etc. Preferably biasing relay 416 is an apparatus that either increases or decreases a pressure signal, and the magnitude of the increase or decrease in the pressure signal can be adjusted. Once the magnitude of the pressure increase or decrease has been set, the magnitude stays fixed until it is manually changed. For example, a burner unit that is firing without enough excess air indicates that springs 192 and 194 (shown in Fig. 3), which resist the opening of air control valve opening 172, are exerting too great a force against the force created by diaphragm 196 of air control valve 172. The volume of secondary air flowing to burner 110 can be increased by adjusting biasing relay 416 to increase the pressure signal to diaphragm 196 of air control valve 172 thereby increasing the force exerted by diaphragm 196 against the force created by springs 192 and 194 further opening air control valve 172. The magnitude of the increase in force generated by diaphragm 196 would then remain constant throughout the firing pressure range of burner 110.
Referring to Fig. 6, the diaphragm (not shown) of biasing relay 416 is preferably connected to line 404 that supplies fuel to burner 110. Preferably, at all times, biasing relay 416 senses the fuel pressure going to burner 110. If the amount of secondary air going to burner 110 must be increased or decreased, biasing relay 416 can be adjusted to change the magnitude of the pressure signal going to diaphragm 196 of air control valve 172 thereby either increasing or decreasing air control valve opening 182 in response to burner firing pressure.
This embodiment provides for a "warm shutdown". Generally, as process temperature _ ....,-.. ___ .. .._x is satisfied (i.e., when the heat output of fire tube 114 exceeds the heat required by the process utilizing burner 110) burner 136 is turned off. When process temperature controller 20 is satisfied, output to alarm(s) 420 and temperature control valve 415 declines.
As the output pressure from the process temperature controller 20 declines, temperature control valve 415 will close, and biasing relay 416 will revert to its normal position and vent the pressure on the air control valve diaphragm 92 (shown in Fig. 5) via vent ports 424 and 425.
Air control valve 172 then returns to its normally closed position - slightly open at the zero position. For all practical purposes, air flow through idle combustion chamber 134 is now blocked.
Following warm shutdown, startup from idle mode (burners off, process warm) preferably proceeds as follows. As process temperature controller 20 requests heat, output from temperature controller 20 goes to alarm(s) 420 and to the temperature control valve 415.
Assuming that the burner has a permission to start, alarm(s) 420 is in a permissive mode, and the control signal from process temperature controller 20 is communicated to the diaphragm of temperature control valve 415. Fuel will then flow to the burner.
This embodiment also prevents stack 31 from sweating during long idle periods.
Preferably, if the burner system is idle (i.e., no heat is required by the process), and low stack temperature is detected, thermostat stack low temperature control 417 outputs pressure to relay 418, and air control valve 172 will open in response to thermostat stack low temperature control 417. Opening air control valve 172 allows air flow to warm stack 31 to prevent sweating by removing heat from the process until process temperature controller 20 detects low process temperatures and begins controlling to initiate the cold start sequence Oescribed above.
Preferably, this embodiment also provides for emergency shutdown and restart of burner 110. If alarm(s) 420 activates, temperature control valve 415 will close and fuel to the burner is interrupted, biasing relay 416 vents pressure from the air control valve diaphragm 92 (shown in Fig.5), and air control valve 172 returns to its idle position. When the problem causing the shutdown is rectified, alarm(s) 420 allows pressure to the diaphragm of temperature control valve 415 and startup will commence for cold startup or startup from idle as described above, depending on the temperature of stack 31 at the time of startup.
This embodiment is useable in concert with the trimming control valve as shown in Fig. 4 and whose function and design are described above. ' The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.
Although the invention has been described in detail with particular reference to the preferred embodiments in the attachment, other embodiments can achieve the same results.
Variations and modifications of the present invention will be obvious to those skilled in the art and it is intended to cover all such modifications and equivalents. The entire disclosures of all references, applications, patents, and publications cited above, and of the corresponding application(s), are hereby incorporated by reference.
Claims (6)
1. A system for controlling a secondary air controller of a heating apparatus comprising a control logic for controlling flow of fuel to the heating apparatus and controlling the opening of a valve of the secondary air controller, said control logic comprising:
a plurality of lines for communicating signals;
a plurality of relays connected to said lines to activate the flow of fuel and the opening of a valve of the secondary air controller;
at least one controller to send a pressure signal to said relays; and a trimming air control valve to control introduction of air into a fire tube of the heating apparatus.
a plurality of lines for communicating signals;
a plurality of relays connected to said lines to activate the flow of fuel and the opening of a valve of the secondary air controller;
at least one controller to send a pressure signal to said relays; and a trimming air control valve to control introduction of air into a fire tube of the heating apparatus.
2. The system of claim 1 wherein said trimming air control valve is linked to an accumulator and responds to an increase in pressure within said accumulator.
3. A system for controlling a secondary air controller of a heating apparatus comprising a control logic for controlling flow of fuel to the heating apparatus and controlling the opening of a valve of the secondary air controller, said control logic comprising:
a plurality of lines for communicating signals;
a plurality of relays connected to said lines to activate the flow of fuel;
at least one controller to send a pressure signal to said relays;
a temperature control valve in communication with said at least one controller to receive a pressure signal from said at least one controller; and a biasing relay in communication with said temperature control valve to vent pressure on said secondary air controller and control the opening of a valve of said secondary air controller.
a plurality of lines for communicating signals;
a plurality of relays connected to said lines to activate the flow of fuel;
at least one controller to send a pressure signal to said relays;
a temperature control valve in communication with said at least one controller to receive a pressure signal from said at least one controller; and a biasing relay in communication with said temperature control valve to vent pressure on said secondary air controller and control the opening of a valve of said secondary air controller.
4. A method for controlling a secondary air controller of a heating apparatus via a control logic to control a flow of fuel to the heating apparatus and to control opening of a valve of the secondary air controller, said method comprising:
communicating signals via a plurality of lines;
connecting a plurality of relays to the lines;
controlling the flow of fuel and the opening of a valve of the secondary air controller via the relays and the lines;
sending a pressure signal to the relays via at least one controller; and providing a trimming air control valve and controlling introduction of air into a fire tube of the heating apparatus.
communicating signals via a plurality of lines;
connecting a plurality of relays to the lines;
controlling the flow of fuel and the opening of a valve of the secondary air controller via the relays and the lines;
sending a pressure signal to the relays via at least one controller; and providing a trimming air control valve and controlling introduction of air into a fire tube of the heating apparatus.
5. The method of claim 4 further comprising the steps of:
linking an accumulator to the trimming air control valve; and sending a pressure signal from the accumulator to the trimming air control valve.
linking an accumulator to the trimming air control valve; and sending a pressure signal from the accumulator to the trimming air control valve.
6. A method for controlling a secondary air controller of a heating apparatus via a control logic to control a flow of fuel to the heating apparatus and to control opening of a valve of the secondary air controller, said method comprising:
communicating signals via a plurality of lines;
connecting a plurality of relays to the lines;
controlling the flow of fuel via the relays and the lines;
sending a pressure signal to the relays via at least one controller;
sending a pressure signal to a temperature control valve via the at least one controller;
sending a pressure signal to a biasing relay via the temperature control valve;
and venting pressure on the secondary air controller via the biasing relay to control the opening of a valve of the secondary air controller.
communicating signals via a plurality of lines;
connecting a plurality of relays to the lines;
controlling the flow of fuel via the relays and the lines;
sending a pressure signal to the relays via at least one controller;
sending a pressure signal to a temperature control valve via the at least one controller;
sending a pressure signal to a biasing relay via the temperature control valve;
and venting pressure on the secondary air controller via the biasing relay to control the opening of a valve of the secondary air controller.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2541606A CA2541606C (en) | 2006-03-31 | 2006-03-31 | Control of an adjustable secondary air controller for a burner |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2541606A CA2541606C (en) | 2006-03-31 | 2006-03-31 | Control of an adjustable secondary air controller for a burner |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2541606A1 true CA2541606A1 (en) | 2007-09-30 |
| CA2541606C CA2541606C (en) | 2014-10-28 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2541606A Active CA2541606C (en) | 2006-03-31 | 2006-03-31 | Control of an adjustable secondary air controller for a burner |
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| CA (1) | CA2541606C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9932989B1 (en) | 2013-10-24 | 2018-04-03 | Rodney T. Heath | Produced liquids compressor cooler |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9353315B2 (en) | 2004-09-22 | 2016-05-31 | Rodney T. Heath | Vapor process system |
| WO2013170190A1 (en) | 2012-05-10 | 2013-11-14 | Heath Rodney T | Treater combination unit |
| US9527786B1 (en) | 2013-03-15 | 2016-12-27 | Rodney T. Heath | Compressor equipped emissions free dehydrator |
-
2006
- 2006-03-31 CA CA2541606A patent/CA2541606C/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9932989B1 (en) | 2013-10-24 | 2018-04-03 | Rodney T. Heath | Produced liquids compressor cooler |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2541606C (en) | 2014-10-28 |
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