US3343418A - Thermal responsive assembly - Google Patents

Description

Sept. 26, 1967 BRAN H: ET AL 3,343,418

THERMAL RESPONSIVE ASSEMBLY Original Filed Sept. l5, 1%} 2 Sheets-Sheet 1 FIG.|

FIGA

I X VEXTORS WILLIAM H. BRANCHEA GLEN A. WHITE.

B X CZW ATTORNEY.

Sept. 26, 19.67 w BRANCHE ET AL 7 3,343,418

THERMAL RESPONSIVE ASSEMBLY Original Filed Sept. 15, 1961 2 Sheets-Sheet 2 S ing t FIG. 2

I N VENTORS.

WILLIAM H. BRANCHE.

GLEN A. WHITE.

ATTORN EY.

United States Patent 3,343,418 THERMAL RESPONSIVE ASSEMBLY William H. Branche, Indianapolis, and Glen A. White,

Westfield, Ind., assignors to Carrier Corporation, Syracuse, N.Y., a corporation of Delaware Original application Sept. 15, 1961, Ser. No. 143,992, now Patent No. 3,216,479, dated Nov. 9, 1965. Divided and this application Aug. 6, 1965, Ser. No. 487,349 1 Claim. (Cl. 73--363) This application is a division of copending application, Ser. No. 143,992, filed Sept. 15, 1961, now Patent No. 3,216,479, for Fluid Control Means.

This invention relates to control means, more particularly to means controlling the flow of fluids in response to the proper utilization of the fluid at a desired delivery point. Particular reference will be had to an embodiment of the invention in connection with a pilot light for gas burners where the flow of gas to the pilot will be controlled in response to the presence of a flame at the pilot.

A variety of situations exist in which it is necessary to control the flow of fluid through a supply conduit so that the fluid flow will be stopped upon the occurrence of some undesirable condition at the point of delivery. To this end, different types of safety valves responsive to the desired condition have been evolved. The positioning of the valve to control fluid flow is effected by some sensing member arranged to detect the presence or absence of the desired condition.

In the case of gas burners, contemporary technological advances have given rise to the utilization of a pilot flame adjacent the gas burner serving to initiate operation of the burner. In most installations, the burner is not maintained operative continuously, and the pilot functions to ignite any gas supplied to the burner so as to permit the on-oif operation required by automatic systems. As is apparent, any gas supplied to the pilot must be burned so as to prevent the flow of inflammable gas into an area Where it might prove dangerous. In order to insure that gas is supplied to the pilot only when a flame is present, controls of the type here involved are employed.

As is the case with all burner equipment, it is desirable that any controls, employed be relatively small, foolproof in operation, and utilizing a minimal number of components so as to minimize maintenance and production costs. It is additionally desirable to promote the proper mixture of air with the gas to attain combustion; and further to insure the sensing of the desired combustion by the sensing member.

It is with these problems and desiderata in mind that the present control means have been evolved, means providing for a compact pilot structure in which gas flow is controlled in a simple eflicient manner; proper air-gas mixtures are implemented; and sensing of the flame is facilitated.

It is accordingly a primary object of this invention to provide an improved control for regulating the flow of fluids in response to conditions at a delivery point.

Another object of the invention is to provide an improved pilot light structure in which the flow of gas to the pilot will be stopped upon the extinguishment of the pilot flame.

A further object of the invention is to provide an improved valve arrangement subject to formation in a compact relatively small volume.

' An additional object of the invention is to provide for an improved mounting for a thermally responsive eler nent, insuring the transfer of heat to the element.

Another object of the invention is to provide a pilot structure in which the pilot flamewill be relatively protected from extinguishment.

A further object of the invention is to provide for de sired air-gas mixtures at the pilot.

These and other objects of the invention which will become hereafter apparent are achieved by provision of a duct through which fluid may be directed to a desired point. A valve member is arranged to control the flow of fluid through said duct, and a member sensing the effect of proper utilization of said fluid at the discharge point of said duct controls the operation of the valve member. In the preferred embodiment of the invention here illustrated, the novel structure will be seen embodied in a pilot light assembly for gas burners. The duct is a pilot stem through which gas is directed to a target plate serving to direct the pilot flame partially to the burner to be lit thereby and partially to a valve controlling sensing element. An ignition or escapement stem is provided for igniting the gas supplied by the pilot stem. The valve is controlled by a magnetically actuated armature, and a magnet for actuation of the armature is coupled to a thermally responsive arm which is arranged to be impinged on by a portion of the flame striking the pilot target plate. A novel chimney structure is provided for mounting the pilot stem and the escapement stem so as to insure proper admixture of primary and secondary air with the gases, and serving to prevent the dissipation of heat and accidental extinction of the pilot flame.

An important feature of the invention resides in the improved construction of the magnetically actuated valve which permits formation of the valve as a simple compact structure occupying a minimal volume and simple in production and maintenance. By use of a disc-shaped armature, proper valve operation is attained regardless of its orientation.

A11 additional feature of the invention resides in the novel chimney mounting for the pilot stem providing for the desired gas-air mixture.

A further feature of the invention resides in the mounting for the sensing element which insures a response of the element only to flame heat and not to other heat in-the area.

Another important feature of the invention resides in the novel target which permits primary aeration.

An additional feature of the invention resides in the sensing arm structure with its warpage preventing structure.

The specific details of a preferred embodiment of the invention and their mode of functioning will be made most manifest and particularly pointed out in clear, concise, and exact terms in conjunction with the accompanying drawings wherein:

FIGURE 1 is a perspective view of a pilot assembly embodying the details of the instant novel control means;

FIGURE 2 is a cross-sectional view taken on line 2-2 of FIGURE 1 illustrating the relationship between the valve, the pilot stem, the target plate, and the sensing arm;

FIGURE 3 is a cross-sectional view taken on line 3-3 of FIGURE 1 illustrating the relationship between the ignition or escapement stem, the pilot stem, and the valve; and

FIGURE 4 is a top plan view of the assembly illustrated in FIGURE 2.

Referring now more particularly to the drawings, like numerals in the various figures will be employed to designate like parts.

The control means forming the subject of this inven tion is an improvement over the unit described in United States Patent No. 2,630,860, issued March 10, 1953. Ref erence may be had to the patent for a description of the preferred usage of the invention.

' The pilot assembly as best seen in FIGURES 2 and 3 is formed with a valve body 11 made up of a nonmagnetic material such as zinc or aluminum. A pilot port 12 extends through the body 11 and is formed to extend along a straight path 13 and a skew path 14 from inlet 15 to outlet 16. The outlet 16 is provided with a tapped recess to receive an orifice structure 17. A valve seat 20 is positioned in the pilot port 12 between the straight path 13 and skew path 14, as best seen in FIGURE 2. The valve member 21 comprises an armature 22 of ferro magnetic material in the shape of a frusto-conical disc having an aperture within which a steel ball 23 is securely held. The diameter of ball 23 is such that it will seat on valve seat 20 blocking fluid flow through port 12. Spring 25 is arranged to engage a flange 26 on armature 22 and bear against an emboss 27 in sealing cup 28.

Escapement port 30 extends through valve body 11 and is formed in a straight path 31 between inlet 32 and outlet 33, which is provided with an orifice structure 34. Orifice structure 34 is a hexhead bolt with an appropriate opening formed therein to permit the passage of desired quantities of gas similar to orifice structure 17.

The escapement stem as best seen in FIGURE 3 is formed of an elongate cylindrical configuration having an open lower end adapted to extend about the opening in orifice structure 34, and having its upper end closed off by dome structure 41. A slot 42 extends through the dome structure and down a portion of the length of the stem so as to insure the burning of all of the gas fed to the stem orifices 43 and 44. Where automatic ignition is desired, an aperture 45 is formed in stem 40, and an electric ignition coil (not shown) of a conventional type is positioned adjacent this aperture to effect ignition of gases passing through the stem.

The pilot stem is similarly formed of an elongate cylindrical configuration with an open lower end of a diameter encompassing the opening in orifice structure 17. The upper end of pilot stem 50 is cut at a slant as best seen in FIGURES 2 and 3 to provide for outlet 51.

A chimney mounting structure or shroud is formed of sheet material such as sheet steel or the like and supports and encompasses the escapement stem 40 and pilot stem 50. The escapement stem 40 is rigidly supported in position between a spaced upper escapement mounting plate 56 and lower escapement mounting plate 57. As best seen in FIGURES 2 and 3 a space is left between the bottom of escapement stem 40 and the top of orifice structure 34 for a purpose to be made hereinafter more apparent. Pilot stem 50 is supported within a rectangular chamber 58 formed within mounting chimney 55.

The target 60 formed as illustrated in FIGURES 2 and 3 is provided with a supporting arm 61 secured to a wall of the chamber 58 surrounding and supporting pilot stem 50.

The configuration of the target 60 is such that most of the gas emitted from the outlet 51 of pilot stem 50 is directed outwardly, to the right as viewed in FIGURE 2, towards the burner to be ignited by the pilot. Some smaller portion of the gas is, however, directed to the left as viewed in FIGURE 2 against the thermally responsive arm 65.

Arm 65 includes leg portion 65a anchored at one end 76 and joining at the other, a generally U-shaped portion 65b and a leg portion 650 fixed at one end 65d to housing 68 and connected to leg 65a through integral bridge portion 652. Arm 65 is made up of a relatively thin band of rigid material such as stainless steel which will warp temporarily under the action of the flame directed thereagainst by the target. The lower end 65b of arm 65 has secured thereto a magnet 66 of alnico or the like. The magnet 66 is secured to the arm by means of an adjustable bracket 69 fastened by screw 70 to U-shaped portion 65b of arm 65 made integral with the arm.

The upper end of arm 65 is secured to a mounting plate by means of rivet 76 or the like fastener. Plate 75 is formed with heat dissipating apertures 77 serving to minimize the heat retention of the mounting plate, and functioning additionally to admit air to the shroud 55 to obtain the desired fuel air ratios.

As seen to the lower left in FIGURE 2, section 65h of U-shaped portion 65b of leg 65 has secured thereto an adjustable screw 78 which acts against contact blades 80 of switch 81 controlling flow of gas to the main burner serviced by the pilot forming the invention.

The purpose of the bracket 69 and adjusting screw 70 is to provide an adjustment for spacing the magnet 66 relative to the valve body 11.

The instant structure reveals an embodiment of a control device by means of which the flow of fluid is controlled in response to the utilization of the fluid at the deisred delivery point. It will be apparent to those skilled in the art that a variety of different types of fluids may be controlled by structures embodying the instant inventive concepts.

By way of example, the invention has been illustrated as utilized in conjunction with a gas pilot assembly 10.

Such pilot assemblies are employed to provide automatic ignition of a gas burner when it is desired to utilize the burner. Thus where gas burners are employed for residential heating purposes, whether for the production of hot water, or area heat, some thermostatic control is generally employed to regulate the supply of gas to the burner. When the thermostat determines the need for heat, the burner gas supply valves are opened supplying necessary fuel to the gas burner. This fuel is ignited by the pilot flame which is constantly maintained.

Since the gas supply to the pilot is constant, it is necessary to provide some control in the event that the flame goes out for some reason such as a draft, liquid spillage or the like.

The instant structure permits this function to be attained. Thus, in use, gas is fed to the ignition or escapement stem 40 by means of some manually controlled valve. The operator initiates gas flow to the escapement stem 40, and effects ignition thereof either manually with a match, or by means of an electric ignition coil. The flame produced by the escapement stem 40 extends into proximity with the discharge opening 51 of pilot stem 50 and against thermal arm 65.

The action of the flame on thermal arm 65 held rigid ly at points 76 and 65d is such as to cause the arm 65 to warp so as to move magnet 66 to the right as viewed in FIGURE 2. This movement of the magnet 66 results in an increase of flux density acting on armature 22 which causes the armature to move to the left as viewed in FIG- URE 2, thereby displacing ball 23 from valve seat 20 which permits the flow of gas through pilot port 12 from inlet 15 to outlet 16.

At outlet of orifice 17, the gas is mixed with primary air from chamber 58 with the resultant air-gas mixture moving upwardly through pilot stem 50. This air-gas mixture has secondary air added to it at outlet 51 and is ignited by the flame of escapement stem 40. With the construction illustrated, the primary air for flow through the pilot stem is induced to pass under and in the proximity of the flame as it passes downwardly through chamber 58 accommodating the pilot stem. During operation of the pilot, the pilot flame and the pilot stem 50 heat the primary air to an extent determined by the size of the flame and the temperature of the stem. This feature established a relation between the primary air and the gas flow from orifice 17 such that substantially constant flame characteristics are obtained over a relatively large variation in the pressure of the gas supplied to. the orifice. If, for example, the temperature of theflame rises, due to an increase in the pressure of the supply gas, the temperature of the air in proximity of the flame and the temperature of the stem also rises. The primary air is then subject to a flame and stem temperature of a higher value which, in turn, apparently reduces the rate of primary air flow as the air expands when subjected to the increased temperature to maintain the flow described.

The action of the flames induces secondary air and also preheats primary air prior to its entrance into chamber 58 through a path indicated by the dotted arrows.

At this time the supply of gas to escapement stem 40 is shut off. The flame at the outlet of pilot stem 50 impinges on target 6t) whence a major portion thereof is diverted to the right as viewed in FIGURE 2 towards the gas burner to be ignited thereby, and a secondary portion of the flame is diverted to the left as viewed in FIG- URE 2 against thermal arm 65 to maintain same in a warped condition permitting magnet 66 to attract arrnature 22.

So long as the pilot flame remains ignited, the arm 65 is warped to this position permitting attraction of the armature 22. Upon the extinction of the flame, the arm cools returning to its original position pulling magnet 66 to a position sufliciently remote from armature 22 so that the flux density of magnet 66 no longer overcomes the force exerted by spring 25 so that the ball is again seated on valve seat 20 shutting off the flow of gas to the pilot stem 50.

When arm 65 returns to its non-warped condition, contact blades 80 are separated, and if these contact blades are arranged in the thermostat circuit the supply of gas to the burner can no longer be initiated. Obviously a variety of signal circuits may be controlled by contacts 80 to indicate the extinction of the pilot flame.

It will be observed by those skilled in the art that the construction of the novel magnetic valve is such as to permit fabrication of the structure in a relatively small volume, light in weight, simple of assemblage and requiring minimal maintenance. The spring biased armature provides for positive orientation of the valve ball 23 against the seat regardless of the position of the valve. The sealing cup 21 serves to prevent any accumulations of foreign matter Within the valve body.

An important feature of the valve 23, together with its actuating mechanism, is the reliability of operation assured by a construction free of linkage or equivalent structure prone to mechanical failure. With the parts shown and described, adjustment may be made whereby the contacts 80 engage either before or after the gap between the magnet 66 and cup 21 is reduced to an extent such that attraction of the armature 22, together with opening of the valve passage, is accomplished.

The mounting shroud 55 for the escapement stem 40 and pilot stem 51 provides for a chimney efiect in which the desired flow of secondary and primary air to the gases supplied to the stems is insured.

The mounting plate 75 for arm 65 with its apertures 77 serves to permit air flow into the shroud and additionally minimizes heat retention by the arm thereby insuring proper functioning thereof.

It is thus seen that a simple means for controlling the flow of fluid has been provided which automatically cuts off fluid flow when the utilization of the fluid at the point of delivery is not as desired. The invention has been disclosed as embodied in a gas pilot whereby extinction of the pilot flame automatically results in a cessation of gas flow. The novel structure is compact, light in weight, with few moving parts, simple of manufacture and maintenance, and functioning regardless of orientation.

The above disclosure has been given by way of illustration and elucidation, and not by way of limitation, and it is desired to protect all embodiments of the herein disclosed inventive concept within the scope of the appended claim.

We claim:

A thermal responsive assembly including a member comprising a first leg portion having an end fixedly secured to supporting structure and a generally .U-shaped free end, a second leg having an end fixedly secured to a supporting structure, said legs being connected by a bridge portion with the area of attachment disposed intermediate the first leg and at the other end of the second leg; an adjustable bracket mounted on a first section of the U-shaped free end of the first leg, said bracket being effective to support valve actuation means; an ad justable switch actuator mounted on a second section of the U-shaped free end of the first leg; said adjustable bracket and actuator being effective upon warpage of the member in response to the application of heat to the first leg to effect valve and switch actuation.

References Cited UNITED STATES PATENTS 2,630,860 3/1953 Cerny et al. 73-36 X 2,868,278 1/1959 Antrim 73363.1 X 3,044,299 6/1962 Weber et al 73363 LOUIS R. PRINCE, Primary Examiner.

S. C. SWISHER, Assistant Examiner.

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