Relighter control system

DESCRIPTION

1. Technical Field

The present invention relates generally to gas burner pilot assemblies and control systems for gas burners ignited by a pilot flame, and more specifically to relighter system for a gas burner pilot assembly used with fuel pipeline heaters.

2. Background Prior Art

A specialized type of heater apparatus is necessary for use on fuel pipelines, including natural gas pipelines. With natural gas fuel pipelines, the need for such heaters arises to prohibit the condensation of hydrocarbons in the pipelines. When there is a reduction in the pressure of the natural gas within the pipeline, such as is typically the case when a percentage of the gas in a main line is diverted to a separate pipeline to service a municipality or the like, the sudden loss in internal pipeline pressure may result in the development of undesirable condensation of hydrocarbons in the pipeline. The development of hydrocarbon condensation may lead to an obstruction or faulty flow of gas. This possible hydrocarbon condensation problem may be avoided by heating the pipeline.

Many gas burning heaters in use today often include a manually operated pilot flame ignition. These manually operated pilot flame ignitions are often provided without safety features such as reliable relighting of an extinguished pilot or main burner shut-off features. Further, many of the gas heaters presently being used are not reliable for preventing hydrocarbon condensation in the pipeline because they do not have safety features for detecting and reacting to pilot-burner flame failure. Further, because many of the heaters presently in use do not have reliable relighting features, they often require continual pilot flames even though the actual burner is used infrequently. The use of continual pilot flames, however, results in wasted fuel and unnecessary pilot burn time, thereby increasing the cost and decreasing the overall life of the burner components.

Additionally, other relighting systems presently in use in the industry have a pilot assembly with a structure having an ignitor terminal extending into the pilot flame. This often results in the deterioration of the ignitor terminal due to constant exposure in the pilot flame and/or loss of the important tolerance of the spacing of the ignitor terminal.

Many of these noted disadvantages have been overcome by U.S. Pat. No. 6,089,856, entitled “Pilot Control Assembly,” and U.S. Pat. No. 5,927,963, a divisional of the '856 patent. Both of these U.S. patents are commonly owned by the assignee of the present invention, and are hereby incorporated by reference herein. The inventions of the '856 and '963 patents resolved many of the above noted disadvantages, primarily by providing a specific structure of a pilot assembly, and by providing a pilot control means which optionally provides a continuous burning pilot or provides an on-demand pilot, both such pilot operations having safety features for shutting down the main burner valve and relighting the pilot, in the event the pilot is extinguished.

Notwithstanding the benefits of the '856 and '963 patents, the system configuration of many gas burner heaters utilizing pilot control means and pilot ignition devices may have certain drawbacks. Often, the burner control system in the prior art devices includes a control system. The control system in prior art devices included a control board with an ignitor coil. The ignitor coil receives a low voltage input (approximately 150-200 volts) and develops a high voltage charge (approximately 15,000 to 25,000 volts). Typically, a terminal is connected to the output of the ignitor coil, and a high voltage wire is connected from the terminal to the ignitor rod. Because of hysteresis, the maximum distance allowable between the ignitor coil and the ignitor rod is approximately 10 ft. At distances greater than 10 feet between the ignitor coil and the ignitor rod, the high voltage and low impedance charge from the ignitor coil becomes unreliable. An unreliable charge may not provide a spark at the ignitor rod tip, thus resulting in unreliable relighting, and the potential formation of hydrocarbon condensation due to the temperature drop from the line heater being down. As a result, prior art control boards and ignitor coils were connected to ignitor rods with a high voltage wire at a span of less than approximately 10 ft.

Additionally, because the high voltage charge created by the ignitor coil, and the proximity of this charge to a lit gas supply, it is often necessary to place the control system and ignitor coil in an explosion proof container. By placing the control system and ignitor coil in a sealed chamber or cabinet, and often an explosion proof container, it is thought that in the event of a gas leak, a potential fire hazard through ignition of any leaked gas may be avoided. Such containers, however, are extremely expensive.

Accordingly, there is a need for a reliable and effective relighter system for a burner control system used with fuel pipeline heaters.

SUMMARY OF THE INVENTION

The present invention provides a system for providing a spark to a pilot burner for a heater for a fuel pipeline. The system generally includes a controller, a pilot burner and an ignition coil. The controller is located at a first location, and the pilot burner is located at a second location remote from the first location. Additionally, the ignition coil is also located at the second location. Typically, the ignition coil is electrically connected to the controller and it receives a voltage input from the controller. After receiving the voltage input, the ignition coil charges until it subsequently provides a voltage output. The ignition coil transfers a current based on the voltage output to create a spark in the pilot burner to ignite an air/fuel mixture in the pilot burner.

According to one aspect of the present invention, a low voltage line connects the controller and the ignition coil. In one embodiment, the first location is located a distance of approximately at least 10 feet from the second location. Additionally, the first location may be located a distance of approximately between 10 feet and 100 feet from the second location. Finally, the first location may be located a distance of at least 100 feet from the second location.

According to another aspect of the present invention, the voltage input the ignition coil receives from the controller is a low voltage input, and the voltage output of the ignition coil is a high voltage output. Generally, the low voltage input received from by the ignition coil is in the range of approximately 10 volts to approximately 200 volts.

According to another aspect of the present invention, an ignitor module is located at the second location and adjacent the pilot burner assembly. The ignitor module has a housing with the ignitor coil and a transformer therein. The transformer is electrically connected to the ignition coil. The transformer receives a first low voltage input from the controller and converts the first low voltage input to a second low voltage input. Typically, the second low voltage input is of a higher voltage than the first low voltage input. The second low voltage input is transferred from the transformer to the ignition coil. In one embodiment, the first low voltage input is approximately 12 volts, and the resulting second low voltage input is approximately 150-200 volts.

According to another aspect of the present invention, the ignitor coil and transformer are potted in the ignitor module housing in a thermoplastic resin. Additionally, the ignitor module also has a terminal strip electrically connected to the transformer and the ignitor coil, and a terminal extending from the ignitor coil and through a wall in the housing.

According to yet another aspect of the present invention, an ignitor rod is provided. The ignitor rod has a first end electrically connected to a terminal at an exit of the ignitor coil, and a second end adjacent the pilot burner. Current corresponding to the high voltage output is transferred from the ignitor coil to the ignitor rod. Conduction of the electrical current between the second end of the ignitor rod and the pilot burner causes a spark to ignite the air/fuel mixture in the pilot burner, thereby creating a pilot flame.

Other features and advantages of the invention will be apparent from the following specification taken in conjunction with the following drawings.

BRIEF DESCRIPTION OF THE DRAWING

To understand the present invention, it will now be described by way of example, with reference to the accompanying drawings in which:

FIG. 1

is a side elevation view of the relighter apparatus of the present invention;

FIG. 2

is a side sectional view of the spark area of the present invention;

FIG. 3

is a top plan view of the ignitor module of the present invention; and,

FIG. 4

is a block diagram of the control system and relighter apparatus of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

While this invention is susceptible of embodiments in many different forms, there are shown in the drawings and will herein be described in detail, preferred embodiments of the invention with the understanding that the present disclosures are to be considered as exemplifications of the principles of the invention and are not intended to limit the broad aspects of the invention to the embodiments illustrated.

Referring now in detail to the Figures, and initially to

FIG. 1

, there is shown a pilot assembly including a relighter system

10

for providing a spark to a pilot burner for a heater for a fuel as constructed in accordance with the teachings of the present invention. Typically, the system

10

generally includes a controller

12

, a pilot burner

14

and an ignition coil

16

. One type of ignition coil

16

is a spark transformer. The controller

12

is located at a first location

18

, and the pilot burner

14

and ignition coil

16

are located at a second location

20

separate from and remote from the first location

18

. One embodiment of the pilot burner

14

is shown in

FIGS. 1 and 2

, however it is understood that the relighter system

10

of the present invention is applicable with other controllers

12

and pilot burners

14

. Additionally, one type of controller

12

includes a control means whereby the control means sends a signal, typically a low voltage signal across an electrical current supply line

38

which is generally a low voltage line, to the ignition coil or spark transformer. As shown in

FIG. 4

, the control means

12

or controller

12

may have computer data operation adapted to receive a signal to ignite the pilot burner and to respond by providing an electrical control to open a gas valve solenoid and also to provide a low voltage signal to the spark transformer. Such operation of the controller is fully explained in U.S. Pat. No. 6,089,856, which is incorporated herein by reference.

Typically, the pilot burner assembly

14

receives a fuel supply which is provided by a pilot fluid supply pipe

22

. The pilot fluid supply pipe

22

is adapted to provide a flow of combustible gaseous fuel therethrough. The fluid supply pipe

22

has a venturi means

24

with at least one opening

26

to expose air to the pipe

22

and to provide for mixing the air with the fuel passing therethrough. As such, the distal end

28

of the fluid supply pipe

22

delivers a gas/air mixture as the pilot fuel to the pilot burner.

A pilot burner head

30

of the pilot burner assembly

14

receives the gas/fuel mixture from the fluid supply pipe

22

. The pilot burner head

30

also receives the ignitor rod

32

, and provides a surface

36

adjacent the tip

34

of the ignitor rod

32

to provide for conduction of electrical current between those two elements to develop an adequate spark to ignite the gas/fuel mixture and create the pilot flame. The ignitor rod

32

is held in place with an ignitor brace

60

which is mounted to the pilot fluid supply pipe

22

and is attached to the ignitor rod

32

through a brace insulator sleeve

62

.

In the prior art, the electrical current for conduction was provided by an ignitor coil located adjacent the controller. The ignitor coil adjacent the controller received a low voltage input and developed a high voltage charge. A high voltage cable was connected from the ignitor coil, adjacent the controller, to the ignitor rod adjacent the pilot burner assembly. Because of hysteresis, the controller and ignitor coil in the prior art were located at a maximum distance of no more than approximately 10 ft. As such, the controller and the pilot burner assembly were proximally positioned at the same location.

Conversely, in the relighter system of the present invention, the controller

12

or control means

12

and the pilot burner assembly

14

are positioned completely separate, and at distinct and remote locations. Similarly, the ignition coil

16

of the present invention is located completely separate and distal from the location of the control means

12

. Further, the ignition coil

16

in the present invention is positioned at the same general location as the pilot burner assembly

14

, as opposed to being adjacent the controller as in the prior art.

As shown in

FIGS. 1 and 4

of the present invention, a system

10

is furnished to provide a spark to a pilot burner assembly

14

for igniting a fuel mixture in a fuel pipeline heater. The system

10

includes the controller

12

being located in the first location

18

. The pilot burner

14

is located at the second location

20

which is remote from the first location

18

. In terms of being located in a remote location, what is meant is that the first location

18

is positioned at a distance from the second location

20

which is greater than what previously was not allowable because of hysteresis during the transfer of a high voltage from the ignitor coil to the ignitor rod. This distance between the first location

18

and the second location

20

is typically greater than 10 feet, and may be preferably at least 25 feet. Similarly, what is meant by being located at the same location is that the members are located at relative location with a relative distance that is typically known as being the maximum allowable to prevent the development of hysteresis (i.e., within approximately 10 feet).

Additionally, in the preferred embodiment of the present invention the ignition coil

16

is also located at the second location

20

, remote from the first location

18

, and adjacent the pilot burner

14

. In the preferred embodiment, the ignition coil

16

is electrically connected to the controller

12

with a low voltage line

38

. When using a low voltage line

38

, the controller

12

may be located a distance of up to 100 feet from the ignition coil

14

. In other embodiments, the controller

12

at the first location

18

may be located a distance of greater than 100 feet from the ignition coil

14

at the second location

20

. As appropriate, the controller

12

provides a signal to the ignition coil

16

through the low voltage line

38

. In the preferred embodiment, the signal provided to the ignition coil

16

from the controller

12

will be a low voltage signal. In such a configuration, the ignition coil

16

receives the signal as a low voltage input, and correspondingly develops a high voltage output

58

. The ignition coil

16

transfers a current based on its high voltage output to create a spark in the pilot burner

14

to ignite the air/fuel mixture in the pilot burner

14

. In the preferred embodiment, while the voltage input received by the ignition coil

16

is a low voltage input, the voltage output developed by the ignition coil

16

is a high voltage output

58

which is necessary to create the spark in the pilot burner

14

.

As shown in

FIGS. 1 and 3

, the ignition coil

16

may be part of a ignitor module

40

. The ignitor module

40

is located at the second location

20

and adjacent the pilot burner assembly

14

. The ignitor module

40

comprises a housing

42

, with the ignition coil

16

and a transformer

44

located therein. The ignitor module

40

also has a terminal strip

46

for electrical connection therewith. In one embodiment, three of the connections on the terminal strip

46

are provided for electrical connection with the wire

38

extending from the controller

12

, including: an input for connection with the primary coil of the ignitor coil

16

at the first terminal location, an input for ground at the second terminal location, and an input from the controller for connection with the flame sensor

66

in the fourth terminal location. The third slot or terminal location on the terminal strip

46

is for a connection to a ground located on the venturi, and the fifth slot on the terminal strip

46

is for electrical connection directly with the flame sensor

66

. Typically, the input for the flame sensor

66

(at the fourth slot) and the fifth slot for connection with the flame sensor are electrically connected. The ignitor coil

16

and transformer

44

in the ignitor module

40

are potted in the housing

42

in a high temperature thermoplastic resin, which may be a phenol. A terminal

49

extends from the output of the ignition coil

16

and through a hole in a wall of the housing

42

. In one embodiment, the transformer

44

receives a first low voltage

46

input from the controller through the low voltage line

38

. The first low voltage input

46

is approximately 12 volts, however, one of ordinary skill in the art understands that any low voltage input, including, but not limited to approximately 12 volts, is acceptable. The low voltage input may be as low as approximately 9 to 10 volts, but preferably at least 12 volts, to approximately 150-200 volts, but typically less than approximately 220 volts. However, greater voltages may be possible as the low voltage input. The transformer

44

subsequently converts the first low voltage input

46

to a second low voltage input

48

, and the second low voltage input

48

is transferred from the transformer

44

to the ignition coil

16

. Typically, the second low voltage input

48

is generally of a higher voltage than the first low voltage input

46

. In one embodiment, the resulting second low voltage input

48

is approximately 150-200 volts, stepped up from the first low voltage input

46

of 12 volts.

The ignition coil

16

receives the second low voltage input

48

from the transformer

44

. The incoming second low voltage input

48

passes through a primary winding circuit (not shown) and a secondary winding circuit (not shown) in the ignition coil

16

that raises the power to a high voltage output of about 15,000 to 25,000 volts. As is understood by one of ordinary skill in the art, the primary winding circuit typically contains numerous turns of a heavier wire, typically copper, that are insulated from each other. The primary circuit wire goes into the ignition coil

16

through a positive terminal and exits through the negative terminal. The secondary winding circuit typically contains numerous turns, typically more than the primary winding, of a finer copper wire, which are also generally insulated from each other. To further increase the coils magnetic field, both windings may be installed around a soft iron core. As the current from the second low voltage input

48

flows through the coil, a strong magnetic field is built up. Then, when the current is shut off, the collapse of the magnetic field induces a high voltage in the secondary circuit that is released through the center terminal, which in one embodiment is a terminal

49

as shown in

FIGS. 1 and 3

. In general, the low voltage input passes through the primary circuit, which induces a high voltage in the secondary circuit, which is then directed to the terminal

49

and the ignitor rod

32

electrically connected to the terminal

49

. The purpose of the ignition coil

16

is to create a voltage high enough (typically at least 15,000 volts) to arc-cross the gap between the tip

34

of the ignitor rod

32

and the pilot burner

14

, thus creating a spark strong enough to ignite the air/fuel mixture for combustion.

As best shown in

FIG. 1

, the ignitor rod

32

has a first end

52

that is electrically connected to the terminal

49

at an exit of the ignition coil

16

. The ignitor rod

32

also has a second end

54

(shown in FIG.

2

), typically having a tip

34

, that is adjacent the pilot burner

14

. The first end

52

of the ignitor rod

32

is connected to the terminal

49

with a mating connector (not shown). In a preferred embodiment, a joy plug at the first end

52

of the ignitor rod

32

connects the ignitor rod

32

to the terminal

49

. An insulating sleeve

56

, preferably a silicon boot, is placed over the terminal

49

and the first end

52

of the ignitor rod

32

to provide electrical insulation for those components and for the current passing therethrough.

Thus, the current corresponding to the high voltage output

58

is transferred from the ignitor coil

16

, through the terminal

49

and to the ignitor rod

32

. Further, as shown in

FIGS. 2 and 4

, the electrical current corresponding to the high voltage output

58

that is transferred through the ignitor rod

32

conducts at the tip

34

thereof with the pilot burner

14

to cause an adequate spark to ignite the air/fuel mixture in the pilot burner

14

, creating the pilot flame.

In one embodiment, as shown in U.S. Pat. No. 6,089,856, and partially schematically illustrated in

FIG. 4

hereto, a flame sensor

66

may be provided to indicate the presence/absence of a pilot flame to the computerized control means

12

which is connected to the sensor

66

by a wire. When the flame sensor

66

indicates that a pilot flame is not present, the control means controls the ignitor rod

32

by providing current to the ignitor module

40

to initiate a spark at the ignitor tip between the tip and the pilot burner wall. The computerized control means is also electrically connected to a pilot fuel supply valve

68

which is in fluid communication with the pilot supply pipe

22

. The control means

12

controls the pilot valve and main valve to open the valves with electrical current, and also maintains the main valve open with electrical current of decreased voltage when the pilot flame sensor

66

senses the pilot flame and provides an indication of the same.

It will be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.