Combined thermocouple and thermopile capable of generating multiple EMF signals

BACKGROUND OF THE INVENTION

Gas fired room heaters and decorative gas fireplace logs are in use in commercial and residential applications in large numbers. Many of these appliances are remotely controlled. These remotely controlled appliances utilize thermocouples and thermopiles to generate singular EMF signals to energize safety devices and activate remote control circuitry. A pilot flame or burner flame in contact with the thermocouple and thermopile generates the EMF signals required by each device via the Peltier heating and cooling effect. Typically at least one thermopile and one thermocouple are mounted to a pilot bracket or gas burner. Newer controls require more than one thermopile mounted to the pilot bracket or gas burner. As the number of EMF generators required to operate the number of control devices increases so does the physical size of the pilot assembly or gas burner bracket. Likewise, as the thermopile device grows in physical size in order to generate an EMF signal sufficient to activate the control devices so does the amount of energy required to generate a flame substantial enough to heat the generators. In addition as the mass of the thermopile increases so does the length of time required to generate the required EMF signal or to dissipate heat fast enough to deactivate the safety control devices connected to them creating potentially hazardous conditions.

The primary object of this invention is to provide a combined thermocouple and thermopile EMF generator capable of producing multiple EMF signals in one unit.

A further object is to provide an improved space factor, that is to provide a smaller pilot or burner gas bracket with a combined thermocouple and thermopile that is capable of generating multiple EMF signals.

A further object is to minimize the number of thermopiles necessary to supply the required EMF signals by utilizing one thermopile to generate primarily two signals although more signals may be generated.

A further object of this invention is to provide multiple EMF signals from one device.

A further object is to provide an improved response time by isolating the combined thermocouple of lesser mass from the thermopile of greater mass.

A further object is to provide a thermocouple and thermopile construction wherein a thermocouple of a construction commonly know to the industry is longitudinally centered within a thermopile of commonly know construction.

A further object is to provide a thermopile and thermocouple construction wherein the conductors of the thermopile are comprised of dissimilar metals joined at each end to form hot and cold junctions, arrayed in a circle and enclosed in a metal sleeve or jacket; and a thermocouple assembly comprised of a standard ferric chrome, nickel chrome or inconel tip; a constantan wire longitudinally centered within and permanently connected to the tip and an insulated copper wire permanently affixed to the outside of the tip. The thermocouple assembly being longitudinally centered within and isolated from the metallic sleeve and thermopile array contained within a metallic sleeve.

A further object of the invention is to provide a thermopile construction wherein wire extension leads connected to cold junctions at each single metal strip at either end of the array provide one EMF signal and one wire extension connected to a cold junction at an intermediate position providing a second EMF signal are arrayed in a circle and enclosed in a metal sleeve or jacket. A thermocouple assembly longitudinally centered within and isolated from the thermopile array contained within a metallic sleeve or jacket adds an EMF of lesser potential thus providing a total of three EMF signals from the combined thermocouple and thermopile.

Yet another object of this invention is to provide such a combined thermocouple and thermopile that is easy to manufacture, sturdy in use, and easy to assemble.

Other objects and advantages and features of this invention will become apparent from the following detailed description and annexed drawings.

SUMMARY OF THE INVENTION

In accordance with the principles of this invention, the above objects are accomplished by providing a combined thermocouple and thermopile as summarized in the abstract. A thermopile comprised of dissimilar metals joined at each end to form hot and cold junctions are arrayed in a circle and enclosed in a metal sleeve or jacket. The thermocouple array of which the thermopile is comprised, is capable of delivering at least two EMF signals. A thermocouple constructed of a tip, a constantan wire and a copper wire lead which is centrally located within the thermopile assembly, with the tip located at the hot junction end and isolated from the metallic sleeve and thermopile array. The combined thermocouple and thermopile provides at least three EMF signals, occupies less space and improves response time when in the presence or absence of a flame.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

is an isometric view of a typical pilot burner with associated thermocouple and thermopile.

FIG. 2

is an isometric view of a typical gas burner with associated thermocouple and thermopile.

FIG. 3

is an enlarged view of a section of the combined thermocouple and thermopile.

FIG. 4

is an isometric view of a preferred form of combined thermocouple and thermopile.

FIG. 5

is a sectional view taken along the line

5

—

5

.

FIG. 6

is an exploded schematic view illustrating the thermopile elements and the wire extension leads used to tap multiple EMF signals.

FIG. 7

is an isometric view of a typical pilot burner with the proposed embodiment attached.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1

shows a typical exemplary pilot burner

10

carried by a bracket

11

. Fittings for connecting the supply tube are designated at

14

. Numeral

12

designates a support member carried by the bracket

11

which carries the thermopile

13

. Numeral

15

designates a support member carried by the bracket

11

which carries the thermocouple

16

.

FIG. 2

shows a typical gas burner

17

with bracket

18

attached. Numeral

19

designates a support member carried by the bracket

18

which carries the thermopile

20

. Numeral

21

designates a support member carried by bracket

18

which carries the thermocouple

22

.

FIG. 3

shows an enlarged sectional view of the combined thermocouple and thermopile. The thermopile assembly is housed within metallic sleeve

23

. The thermopile

24

is separated from the metallic sleeve

23

by insulator

25

. The thermocouple assembly is comprised of tip

26

which is affixed to an insulated

27

constantan wire

28

at

43

and an insulated copper lead

29

which is affixed to a constantan wire

28

at

42

is centrally positioned within thermopile assembly. Thermopile leads

30

are affixed to the thermopile array at

41

. Thermocouple lead

29

and thermopile leads

30

exit the assembly through strain relief

31

which is crimped to the sleeve

23

at

32

. Wire leads

29

and

30

are crimped within strain relief

31

at

33

to prevent their dislocation in the event of excessive force on the leads and to maintain the relationship of the thermocouple assembly relative to the thermopile

24

, insulation

25

and metallic sleeve

23

. Thermocouple tip

26

is isolated from thermopile sleeve

23

by insulation

25

to prevent thermal and electrical conductance through the thermopile sleeve

23

. Wire lead

34

is permanently affixed to thermocouple tip

26

to function as the cold junction and ground.

FIG. 4

is an isometric view of the preferred embodiment which shows thermocouple tip

26

which is isolated from thermopile sleeve

23

by insulation

25

. Strain relief

31

is shown crimped

35

to thermopile sleeve

23

. Thermopile wire leads

30

and thermocouple wire leads

29

are shown crimped within strain relief

31

.

FIG. 5

is a sectional view

5

—

5

of the combined thermocouple and thermopile. The thermopile elements

35

consisting of two groups of dissimilar elements

36

and

37

joined at their ends to provide hot thermocouple and cold thermocouple junctions. The two groups of elements are arrayed circularly as illustrated. Insulation

25

separates the thermocouple array from the metallic sleeve

23

. The insulated copper wire lead

38

of the thermocouple is centrally positioned and isolated from the thermopile by the wire lead insulation

39

and an insulating magnesium oxide material

40

shown in FIG.

3

.

FIG. 6

shows the assembly of the thermopile elements developed rather than being in a circular configuration. As may be seen element

36

is joined at one end to an element

37

forming a hot junction as designated by numeral

41

. The element

36

is joined at its opposite end to the next adjacent element

37

forming a cold junction as designated at

42

. The junctions are formed by spot welding the outer ends of the elements. The hot junctions are formed at one end and the cold junctions are formed at the opposite end. Numerals

43

, and

45

designate the electrical terminal connections to the cold junctions which provide the maximum EMF signal from the thermopile. Numeral

44

designates an intermediate terminal connection to a cold junction which provides a second lesser value of EMF.

FIG. 7

shows a typical pilot burner

46

carried by bracket

47

. Fittings for connecting the supply tube are designated at

48

. Numeral

49

designates a support member carried by the bracket

47

which carries the combined thermocouple and thermopile. Numerals

50

,

51

,

52

, and

53

designate the combined thermocouple and thermopile leads exiting the preferred embodiment.

The thermopile configuration as described and shown is uniquely different from prior art constructions which as previously indicated typically utilize two electrical terminal connections to provide one EMF signal. The construction as shown is an improved design utilizing three terminals for providing two EMF signals.

The configuration as described and shown is uniquely different from prior art constructions which as previously indicated is comprised of a thermopile consisting of flat wires or bands constituting a radial design with welds between flat surfaces adjacent to ends of the flat wires; and a centrally located thermopile which consists of a nickel chrome or ferric chrome tip, an insulated constantan wire permanently connected to the tip and an insulated copper lead wire permanently connected to the constantan wire positioned longitudinally. The combined unit which has three electrical leads eminating from the strain relief is capable of providing two EMF signals. Where the thermopile has more than two electrical connections the combined thermopile is capable of providing three EMF signals. A combined unit of the type previously described is capable of operating three safety devices or remote controls.