US2682016A

US2682016A - Burner control system

Info

Publication number: US2682016A
Application number: US41129A
Authority: US
Inventors: Russell B Matthews
Original assignee: Milwaukee Gas Specialty Co
Current assignee: Milwaukee Gas Specialty Co
Priority date: 1948-07-28
Filing date: 1948-07-28
Publication date: 1954-06-22
Anticipated expiration: 1971-06-22

Description

June 1954 R. B. MATTHEWS BURNER CONTROL SYSTEM 2 Sheets-Sheet 1 Filed July 28, 1948 h m I m W I I n n N u! R WY 7 Qh W Qmv NO mu WNW June 22, 1954 R. B. MATTHEWS 2,682,

BURNER CONTROL SYSTEM Filed July 28, 1948 2 Sheets-Sheet 2 {35/ 194mm, J z

Patented June 22 2,682,016 BURNER CONTROL SYSTEM Russell B. Matthews, Wauwatosa, Wis., assignor to Milwaukee Gas Specialty Company, Milwaukee, Wis., a corporation of Wisconsin Application July 28, 1948, Serial No. 41,129

6 Claims.

This invention relates, in general, to burner control systems, and has particular relation to burner control systems of the type in which an electric circuit for an electroresponsive valve in ject to the heat of a pilot burner.

While the particular systems which I shall describe hereinafter in connection with the drawings are, in general, of the type in which there is under the control of the thermoelectric generator an electroresponsive valve in the fuel supply pipe for a main burner combined with a thermoelectric safety shutoff valve for the fuel supply for the pilot burner whereby 100% shutoff may be secured, it is to be understood that the invention in its broader aspects is not limited to this particular type of system, but may be embodied in other systems as suitable and desired.

One of the main objects of the present invention is to provide an improved burner control system wherein means is provided for utilizing a thermoelectric generator subject to the heat of the pilot flame to control the flow of current through an electron tube, the output of which is used to control the circuit for the electroresponsive valve in the fuel supply pipe for the main burner.

Another and more specific object of the invention is to provide an improved burner control system wherein the flow of current through the electron tube-the output of which controls the circuit for the electroresponsive valve in the fuel supply pipe for the main burner-is controlled (1) by passing current generated by the thermoi electric generator through a coil located on the outside of and in uxtaposition to the electron control grid.

Another object of the invention is to provide in a burner control system of the class described means operated by the output of the electron tube to open and hold open the electroresponsive valve in the fuel supply pipe for the main burner when the pilot burner is ignited, and in which extinguishment of the pilot flame cuts off the flow of current through the electron tube, thus deenergizing the electroresponsive valve which operates to shut off the supply of fuel to the main burner.

Another object of the invention is to provide in a burner control system of the class described means for controlling the'electroresponsive valve without mechanical contacts or the like.

Further objects and advantages of the invention will be apparent from the following detailed description, taken in connection with the accompanying drawings in which:

Figure 1 is a diagram showing schematically the parts and circuit connections of one form of system embodying the present invention; and

Figure 2 is a diagram similar to Figure 1, showing the parts and circuit connections of another form of system embodying the present invention.

Referring first to the embodiment of the invention shown in Figure 1, the burner indicated at I is a main burner. It may be the main burner for a room or space heater, or it may be the burner for a water heater or for a floor furnace,

gas range, or any other burner, and of any suitable construction.

A fuel supply pipe or conduit 2 leads to the burner l chamber 3 to which air is admitted through adjustable air inlets (not shown), as well understood in the art. The flow of gas through the conduit 2 is controlled by a valve l of any suitable electroresponsive or electrically operated type. For purposes of illustration, the valve 4 may be a solenoid valve operated to open position by the flow of electric current through its coil and to closed position by a spring.

Interposed in the fuel supply pipe 2 anterior of valve 4 is a thermoelectric safety shutoff valve 8. The thermoelectric safety shutoff valve 8 it comprises a valve body having an inlet at 9 for receiving gaseous or other fuel and an outlet it through which this fuel is delivered to the valve 4 and thence, when valve 4 is open, to the main burner. Contiguous sections of pipe 2 are connected to inlet 9 and outlet is. A passage, shown more or less diagrammatically in dotted lines at H, provides for communication between inlet 9 and outlet l0, and a safety shutoff valve, shown in dotted lines at I2, is adapted to seat, for example, upon a valve seat at one end of pas- An electromagnet having a magnet frame it A coil 5| is located physically on the outside of the vacuum tube 39 and connected electrithereby the valve l2 open when the thermocally so that the magnetic field produced by electric generator-such as a thermocouple or flow or" current through it opposes that produced thermopile-is heated by the pilot flame. When 5 by coil 33 and thereby allows diode 38 to conthe pilot I3 is extinguished, the electromagnet, duct. The coil 5| is connected in series circuit which is connected in circuit with the thermorelation with the elements of a thermoelectric electric generator, ceases to hold the valve l2 generator 52 (thermocouple or thermopile) which open, and this valve moves to closed position, for is disposed so that the hot junction 53 thereof example, under the action of a spring l8 to shut (or hot junctions) is subject to the heat of the off the supply of fuel to burner I; also the supply pilot flame as shown. of fuel to the pilot burner. In operation, cocking oi the thermoelectric A reset button is adapted to be pressed safety shutofi valve 8 by depressing the button inwardly to move valve I? to open position with IS opens the valve l2, thus admitting gas to the accompanying movement of armature IE to atpilot burner l3 which, when ignited, heats the tracted position and to hold the armature in hot junctions of the thermoelectric generators attracted position until the pilot is ignited and I1 and 52. In cocking or resetting the thermoheats the thermoelectric generator sufiiciently electric safety shutoff valve, the flow interrupter to retain armature l6 attracted and valve 5?. open. valve member moves to closed position to and a coil I5 is adapted for holding armature l6 connected to valve l2 in attracted position and A flow interrupter valve 2Q may be provided 0 shut oil the flow of fuel to the main burner for shutting off the flow of fuel to the main burner during the resetting operation and until the valve I2 is held in open position by the electromagnet and button |9 is released and returned to its outwardly projected position with accompanying operation of the flow interrupter valve 2s to open position. The details and mode of operation or a suitable reset and how interrupter valve arrangement are shown and deer-iced in the above identified patent of Clarence Wantz; also in Charles J. l-lildebrecht Patent No. 2,1l4/l6, issued April 19, 1938.

The pipe 2| for supplying fuel to the pilot burner l3 may be connected, for example, as shown more or less diagrammatically at 22 to the interior of the body of the thermoelectric safety shutoff valve 3 between the above mentioned valve seats at opposite ends of the passage 1|. In this way the valve it, when in closed position, shuts off the supply or fuel to both the main burner and pilot burner l3, and fuel flows to the pilot burner l3 whenever the valve I2 is open and regardless of whether the now interrupter valve 29 is or is not open.

Electric power for operating the valve :3 is supplied from a suitable source, for example, from the line wires 23 of a suitable source of alternating current, such as a household current supply line of the type which averages about 115 volts.

6 be supplied, for example, by the secondary winding 24 of a transformer having a primary winding 25 connected to the line wires 23.

One side of a secondary 3i is connected by a conductor 32 to. a rectifier 33 at 31%. The other side of secondary 3| is connected by a conductor 35'to rectifier 33 at 35. One side of rectifier 33 is connected by a conductor it to the anode 33 of an electron tube 39 shown in the form of a diode. The cathode is of tube 3? is connected to the other side of rectifier 33 by a conductor 4|.

The rectifier $3 energizes a coil 43 disposed in proximity to tube 39 and connected at one end by a conductor 4% to conductor 3'5 between the rectif er and tube. The other end of coil 13 is connected to a conductor through an adjustable control 46. A third secondary d! has its opposite sides connected by conductors 63 and ll? to a heater 56 for the cathode dd.

When coil i3v is energized without energization of a coil 5| to, be presently described, the coil as directs magnetic fiux lines across the electron travel from cathode lil to anode 33 to prevent the tube 39 from conducting.

Power for the operation of the valve I during the resetting operation and until the pilot I3 is ignited and heats the thermoelectric generator sufficiently to hold valve l2 open. Then upon release of button It, valve member 28 moves to open position, admitting gas to solenoid valve 4.

When the pilot burner I3 is ignited, the flame thereof also heats the hot junction of the thermoelectric generator 52, thus setting up a flow of thermoelectric current through the coil 5|. Line voltage applied to the primary induces a voltage in secondaries 3| and 4? and applies voltage to the elements of diode Coil 5| is, as previously stated, physically located on the outside or diode 39 and is connected electrically so that the magnetic field produced by the flow of current set up through it by the heat of the pilot burner on the hot junction of the thermoelectric generator 52 opposes that produced by the coil 43, thus allowing diode 3?} to conduct. The rectifier 33 also supplies plate voltage to the diode 39, and when coil 5| is energized, the diode conducts and causes current to flow through the conductor Al.

Extinguishment of pilot burner i3 removes the source of heat from the hot junction of the thermoelectric generator 52 which cools, thereby decreasing the flow of current to the coil 5|. This decreases the magnetic held of the coil 5| and the magnetic field of the coil takes precedence and cuts off the fiow of current through the diode 35, thereby deenergizing and closin the solenoid valve. This opens the contacts 28, 29, thereby deenergizing the solenoid valve which operates to closed position shutting off the supply of iuel to. the main burner.

Extinguishment of pilot burner 53 also removes the source of heat from the hot junction of the thermoelectric generator H which cools and thereby discontinues or decreases the flow of current to the coil l5 of the thermoelectric sa iety shutoff valve 3. This valve ll thereby operates to closed position, shutting ofi the supply of fuel to the pilot burner [3 and also provides a safety shutoff for shutting on the supply of fuel to the solenoid valve 4.

The conductor 4|, which leads from the cathode of diode 39 is connected to the grid 62 of thyratron 6| which in turn is connected in series circuit relation with the grid 63 of thyratron by a conductor 64. The conductor 65, which is connected to the side of rectifier 33 opposite the side to which conductor 3"? is connected, is connected to the negative side of a bias cell or battery 65. The positive side of cell 65 is connected through conductors B6, 6?, and 6B and resistors 69 and 7D to anode H in parallel with cathode i and anode 16 in parallel with cathode 12.

One side of secondary 2c is connected by a conductor 73 to one side of the coil of solenoid valve 4. The other side of secondary 2A is connected by a conductor M to cathode '55 of thyratron 6i. The anode E6 of thyratron ti is connected by a conductor ii to the other side of the coil of the solenoid valve 4. The system shown in Figure 1 also has a resistor shown at 78. The tubes til and 6! are shown as provided with heaters indicated diagrammatically at 30.

In the operation of the system shown in Figure 1 the output of diode 39 is fed through the resistor "8. The flow of current through resistor it produces a positive bias on the grids of thyratrons cc and 6! which are connected up backto-baok. The application of the positive bias 1 causes the thyratrons to conduct, each one conducting when the plate is positive with respect to the cathode. This means that each tube conducts only during one-half of the cycle, causing the flow of alternating current through solenoid valve 5 which, being an A. C. valve, is opened and held open for the passage of fuel to the main burner I.

The purpose of the bias cell 65 in the grid circuit is to maintain a negative potential on the grids which prevents the thyratrons from firing when no current is fiowing through the resistor it, this being the condition that exists when the thermoelectric generator 52' is cold and the coil 5i" is deenergized.

The system shown in Figure 2 is the same as the system shown in Figure 1 except that the thyratrons 6t and 6! are used as a full wave rectifier, causing direct current to flow through the solenoid valve 5' the resistor 16'. The other parts and circuit connections of the system shown in Figure 2 which correspond with the parts and circuit connections shown in Figure 1 are designated by primed reference characters corresponding to those used in Figure 1. The system shown in Figure 2 permits the use of a D. C. solenoid valve t. The operation of this system is the same as that described in connection with the preceding embodiment of the invention, and therefore will not be repeated.

The embodiments of the invention shown in the drawings are for illustrative purposes only, and it is to be expressly understood that said drawings and the accompanying specification are not to be construed as a definition of the limits or scope of the invention, reference being had to the appended claims for that purpose.

I claim:

1. Control apparatus consisting of a first circuit including an electron tube having an anode and a cathode and means for energizing said tube to produce a flow of electrons from said cathode to said anode, and a flow of electric current in said circuit, a control circuit under control of electric current flow in said first circuit, first magnetic flux directing means connected in circuit with said first circuit for directing by energization of said first circuit magnetic flux lines across the electron travel from said cathode to said anode whereby to prevent the tube from con ducting electric current, a condition-responsive circuit including means responsive to a predetermined condition for directing magnetic flux lines in opposition to the magnetic flux lines when current flows through directed by said first magnetic flux directing means to cause said tube and said first circuit to conduct electric current to which said control circuit is responsive, said first magnetic fiuX directing means and said means responsive to a predetermined condition for directing magnetic flux lines in opposition to the magnetic flux lines directed by said first magnetic directing means constituting the sole magnetic flux directing means in co-acting relation with said electron tube, and a pair of thyratrons having grids connected in series in said control circuit.

2. Control apparatus consisting of a first circuit including an electron tube having an anode and a cathode and means for energizing said tube to produce a fiow of electrons from said cathode to said anode and a flow of electric current in said circuit, a control circuit under control of electric current flow in said first circuit, first magnetic flux directing means connected in circuit with said first circuit for directing by energization of said first circuit magnetic iiux lines across the electron travel from said cathode to said anode whereby to prevent the tube from conducting electric current, a conditiornrespcnsive circuit including means responsive to a predetermined condition for directing magnetic flux lines in opposition to the magnetic flux lines directed by said first magnetic flux directing means to cause said tube and said first circuit to conduct electric current to which said control circuit is responsive, said first magnetic flux directing means and said means responsive to a predetermined condition for directing magnetic fiux lines in opposition to the magnetic fiux lines directed by said first magnetic flux directing means constituting the sole magnetic flux directing means in co-acting relation with said electron tube, a pair of thyratrons having grids connected in series in said control circuit, and a bias cell in the grid circuit for said thyratrons for preventing the thyratrons from firing when the magnetic fiux directing means in the condi tion-responsive circuit is deenergized.

3. Control apparatus consisting of a first cir cuit including an electron tube having an anode and a cathode and means for energizing said tube to produce a flow of electrons from said cathode to said anode and a flow of electric current in said circuit, a control circuit under control of electric current flow in said first circuit, first magnetic flux directing means connected in circuit with said first circuit for directing by energization of said first circuit magnetic fiux lines across the electron travel from said cathode to said anode whereby to prevent the tube from conducting electric current, a condition-responsive circuit including means responsive to a predetermined condition for directing magnetic flux lines in opposition to the magnetic flux lines directed by said first magnetic flux directing means to cause said tube and said first circuit to conduct electric current to which said control circuit is responsive, said first magnetic flux directing means and said means responsive to a predetermined condition for directing magnetic flux lines in opposition to the magnetic flux lines directed by said first magnetic flux directing means constituting the sole magnetic flux directing means in co-acting relation with said electron tube, a pair of thyratrons having grids con nected in series in the control circuit, and a bias cell in the grid circuit for said thyratrons for preventing the thyratrons from firing when the magnetic flux directing means in the condi- 7 tion-responsive circuit is deenergized, the output of the electron tube being fed through a resistor and the thyratrons being used as a full wave rectifier whereby to cause direct current to flow in the control circuit when electric current flows through the resistor.

4. Control apparatus comprising a first circuit including an electron tube having an anode and a cathode and means for energizing said tube to produce a flow of electrons from said cathode to said anode and a flow of electric current in said circuit, a control circuit under control of electric current flow in said first circuit, first magnetic fiux directing means for directing magnetic fiux lines across the electron travel from said cathode to said anode whereby to prevent the tube from conducting electric current, means for directing magnetic flux lines in opposition to the magnetic flux lines directed by said first magnetic flux directing means to cause said tube and said first circuit to conduct electric current to which said control circuit is responsive, and a pair of thyratrons having grids connected in series in said control circuit.

5. Control apparatus comprising a first circuit including an electron tube having an anode and a cathode and means for energizing said tube to produce a flow of electrons from said cathode to said anode and a flow of electric current in said circuit, a control circuit under control of electric current flow in said first circuit, first magnetic fiux directing means for directing magnetic flux lines across the electron travel from said cathode to said anode whereby to prevent the tube from conducting electric current, means for directing magnetic flux lines in opposition to the magnetic flux lines directed by said first magnetic flux directing means to cause said tube and said first circuit to conduct electric current to which said control circuit is responsive, a pair of thyratrons having grids connected in series in said control circuit, and a bias cell in the grid circuit for said thyratrons for preventing the thyratrons from firing when the means for directing magnetic fiux lines in opposition to the 1 8 magnetic flux lines directed by said first magnetic flux directing means is deenergized.

6. Control apparatus comprising a first circuit including an electron tube having an anode and a cathode and means for energizing said tube to produce a flow of electrons from said cathode to said anode and a flow of electric current in said circuit, a control circuit under control of electric current flow in said first circuit, first magnetic flux directing means for directing magnetic flux lines across the electron travel from said cathode to said anode whereby to prevent the tube from conducting electric current, means for directing magnetic flux lines in opposition to the magnetic flux lines directed by said first magnetic fiux directing means to cause said tube and said first circuit to conduct electric current to which said control circuit is responsive, a pair of thyratrons having grids connected in series in the control circuit, and a bias cell in the grid circuit for said thyratrons for preventing the thyratrons from firing when the means for directing magnetic flux lines in opposition to the magnetic flux lines directed by said first magnetic flux directing means is deenergized, the output of the electron tube being fed through a resistor and the thyratrons being used as a full wave rectifier whereby to cause direct current to fiow in the control circuit when electric current fiows through the resistor.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,206,008 Spencer June 25, 1940 2,217,187 Smith Oct. 8, 1940 2,261,092 Peterson Oct. 28, 1941 2,306,578 Wetzel Dec. 29, 1942 2,329,423 Steghart Sept. 14, 1943 2,352,657 Potts July 4, 1944 2,432,748 Glass Dec. 16, 1947 2, -l42,l45 Ray May 25, 1948 2,518,804 Marvin Aug. 15, 1950