US2008151A - Fuel feeding device for oil burners - Google Patents

Description

July 16, 1935. R. E NEST ET AL FUEL FEEDING DEVICE FOR OIL BURNERS 2 Sheets-Sheet 1 Filed Feb. 17, 1934 v MYWN l INVENTOR RICHARD E.N.5T ND BY 170mm CELL/077 9 M AT ORNEYS July 16, 1935. NEST ET AL I 2,008,151

FUEL FEEDING DEVICE FOR OIL BURNERS Fil ed Feb. 1'7, 1954 2 Sheets-Sheet 2 J: I a kttri i m; j i J w f r INVENTOR. R/cHARn EJVESTAND;

DONALD U.ELLIOT ATTORNEYS.

Patented July 16, 1935 FUEL FEEDING DEVICE FOR 011. BURNERS Richard E. Nest and Donald C. Elliot, West Springfield, Mass., assignors to Gilbert & Barker Manufacturing Company, West Spring- I field, Mass., a corporation of Massachusetts Application February 17, 1934, Serial No. 711,687

2 Claims. (01. 158-86) This invention relates to improvements in liquid fuel burners of the type in which the fuel is fed in vapor form to the burner and of the 'so-called high-low" type, wherein combustion is usually maintained continuously in part of the burner to provide a low fire and wherein combustion is eifected in other parts of the burner, as and when additional heat from the burner is required.

More particularly, the invention relates to improved fuel feeding means which have been particularly designed to meet the needs of a burner of the general class described.

Such burners are usually supplied with fuel from a reservoir in which fuel is maintained at a constant level and from which fuel flows by gravity to the burner. For the high-low type of burner it has been customary to provide separate supply pipes from the reservoir to the burner and the flow of fuel in one of these pipes,--that supplying the high fire section of the burner,-is controlled by a valve which opens when there is a demand for heat and closes when such demand has been satisfied. The flow through the other pipe which supplies the low fire section of the burner is usually controlled by a valve which is fixed in a position adjusted to give a certain outlet port area. With this prior art arrangement, we have found that there is an increase in the amount of fuel supplied to the low fire section of the burner when the burner is operating on full or high fire, and an excessive amount of fuel is consumed at such time in the low fire section of the burner. The desired condition is to have the low fire section of the bu ner consume fuel at substantially the same rate, irrespective of whether the burner is operating on low fire or high fire. The constant outlet port area was originally thought to insure this result but experiment has proved that the increase in temperature of the burner which occurs when the change is made from low fire to high fire causes indirectly, in a manner hereinafter explained, an

increase in the pressure effective to force fuel to the low fire section of the burner.

The object of this invention is to provide'means for insuring a substantially constant flow of fuel to the low-fire section of the burner under both conditions of operation.

More particularly, the invention provides a means automatically operable on the opening of the high fire control valve to reduce the effective outlet port area of the low fire control valve, or otherwise to restrict the area at some point in the supply line to the low fire section of the burner to compensate for the increase in the pressure effective to force the fuel through such line.

The invention will be disclosed for illustrative purposes in connection with the accompanying drawings, in which:

Fig. 1 is a side elevational view, with parts broken away, of a fuel feed controlling apparatus embodying the invention;

Fig. 2 is a cross sectional view taken on the line 2-2 of Fig. 1, showing the control valves positioned for low fire operation of the burner;

Fig. 3 is a View taken similarly to Fig. 2, and showing the valves positioned for high fire operation of the burner;

Fig. 4 is a plan view of the burner base;

Fig. 5 is a sectional view taken on the line 5-5 of Fig. 4; and

Fig. 6 is a small scale view showing in more or less conventional form, the complete fuel feeding system. I

Referring to these drawings, the control unit shownin Figs. 1, 2 and 3 is intended for use with a burner of the general type shown in Figs. 4 and 5 and is interposed in the fuel supplypiping of such burner in the manner indicated in Fig. 6.

The burner is of the type in which combustion may be maintained at a low rate when there is no demand for heat from the burner, and increased to a high rate when such a demand exists. As indicated in Fig. 6, the burner is of theperforated combustion tube type,--embodying a base ring 10, shown separately in Figs. 4 and 5, from which the perforated combustion tubes ll upstand. Fuel from a supply tank I2 is conveyed by a pipe l3 to the control unit 14 and distributed, under the control of valves contained in such unit, by pipes l5 and Hi to the burner base. supplies fuel at all times to the burner base to maintain combustion at a low rate. The pipe l6 supplies fuel to base l0 intermittently, as and when required, for the high fire and its valve (contained in unit I l) is electrically actuated under suitable control, as for example under the controlof a room thermostat I! which closes the electrical circuit l8 when there is a demand for heat and opens that circuit when the demand has been satisfied.

The wires l8 extend through the removable cap ill on unit M, as shown in Fig. 1, to terminals 20 on a panel 2|, supported by and insulated from a bracket 22 upstanding from the top wall of unit It. These terminals 2|] are connected by wires (not shown) to an electromagnet 23 which is supported by a bracket 24, fixed to an upright 25 The pipe I5.

. in the base wall of chamber 35.

'38 can enter the chamber only by way of passages upstanding from the top wall 'of unit l4. The armature 26 of the electromagnet is pivoted to bracket 24 at 21 and has an extension arm 28 which at its free end is forked to straddle the screw threaded upper end of a valve stem 29. The arm 28 is also slotted intermediate its ends to receive the stud 25' which projects upwardly from the central part of the bracket 25 to receive the screw l9 by which the cap I9 is held in place. The stem 29 is mounted for vertical sliding movement in a hub 30 upstanding from the top wall of unit I4. Suchhub is slotted at 3! to receive a pin 32 fixed in and passing transversely through stem 29, whereby the stem is held against rota tion. The forked end of arm 28 underlies a collar 39 adjustably mounted on stem 29. Hence, when magnet 23 is energized, stem 29 will be lifted and the valve controlling the inlet to pipe l6 opened. A spring 34 encompassing stem 29 and disposed within the chamber 35 in unit 14, acts between the upper wall of such chamber and a transverse pin 36 on stem 29 to close the valve. A collar 31, adjustably mounted on stem 29, is adapted to abut the top of hub 30 and limit the downward movement of stem 29 by spring 34. This collar is usually so adjusted as to allow the valve to completely close.

The chamber 35 is adapted to contain the fuel which is maintained therein at a constant level, such as that indicated by the line l--l, by any suitable means. For example, the main supply pipe l3 feeds oil into a cored passage 38 (Fig. 2)

Oil from passage 39 (Fig. 2) under the control of a valve 40 operated by a float 4| and the levers 42 in the usual way. Extending upwardly from the base wall of chamber 35 to a point above the level l-ll are two hollow hubs 43 and 43 ' affording wells 44 and 44, connected by lateral passages 45 and 45', respectively, to the pipes l6 and I5. Fixed in the base of well 44 and extending upwardly therein in spaced concentrical relation therewith, is a sleeve 46 to the interior of which fuel is supplied from chamber 35 by way of passages 41. The lower end of stem 29 is of slightly less diameter than the rest and such end slidably fits the interior wall of sleeve 46. A passage 48 extends from the lower end of stem 29 axially upward therein and then laterally outward to its periphery to communicate with chamber 35 at a point which will always lie above the level I--l, regardless of whether or not the valve is in open or closed position. for venting purposes. The lower end of the stem has a vertical'slot 49 therein through which fuel from sleeve 46 can pass laterally out into well 44 and enter passage 45, provided of course that stem 29 is raised enough to expose the slot 49 above the top of sleeve 46. The valve is shown fully closed in Fig. 2 and fully open in Fig. 3. The purpose of Fig. 3 is simply to show another position of the valve and much of the mechanism shown in Fig. 2 has been omitted from Fig. 3.

Associated with the well 44' are other parts, 45' to 49',-which are duplicates of the parts 45 to 49. The stem 29' acts as a'valve similarly to stem 29 and is similarly mounted in a slotted hub 30' except that no separate valve closing means similar to spring 34 is provided.

The control unit, as thus far described, is of old form and the present invention relates to an operation of the valve on stem 29' in coordinated relation with the valve on stem 29 for the accomplishment of certain useful results in a burner of the general type shown in Figs. 4 and 5. In the old form of control unit, the valve on stem 29' was manually adjustable and was set -to afford at all times a certain definite effective outlet port area, i. e., that of the upper portion of slot 49' (Fig. 2) which lies above the top of sleeve 46'. According to the present invention, this valve is automatically movable to vary the effective outlet port area when the valve on stem 29 is opened,-- the purpose being to cut down the effective area of the port, through which oil is supplied to the low fire section of the burner, whenever the high fire section of the burner is supplied with fuel.

To accomplish this purpose, a lever 5|] is pivotally mounted at its central point on a stud 5| fixed to bracket 25 and has near each end outwardly projecting pins 52 and 52. The pin 52 is engaged in a circumferential groove formed in collar 31, so that vertical movement of stem 29 will rock the lever. The pin 52' extends between two collars 53 and 54, each adjustably mounted on stem 29'. These collars are spaced apart a distance greater than the diameter of pin 52' to provide lost motion whereby the stroke of stem 29 may be less than that of stem 29. The arrangement is such that an opening of the valve on stem 29 causes a partial closing of the valve on stem 29' but not a complete closing thereof because the collar 54, by abutment with hub 30', prevents. As shown in Fig. 3, the valve on stem 29 is partly open while that on stem 29 is fully open. When stem 29 is lowered into the completely closed'position shown in Fig. 2, the valve on stem 29 will be more widely opened,--that is more of the slot 49 will be exposed above the top of sleeve 46' to provide increased effective port area for oil to flow into well 44. With the valve on stem 29 in fully closed position, as in Fig. 2, the collar 53 is adjusted on stem 29' until the desired maximum degree of opening of the valve on stem 29' is secured. Then the collar 54 is adjusted on stem 29 to fix the minimum degree of opening of the valve on stem 29'. Obviously, various other mechanisms will readily occur to those skilled in the art for performing the described functions of valve operation and enabling the desired adjustments thereof and it is not intended to limit the invention to the details of the one specific mechanism herein described as an illustrative example of one suitable means for securing the desired results.

Referring now to Figs; 4 and 5, it is deemed essential to a proper understanding of the in vention to describe the special type of burner for which the improved control unit is designed. The burner base In includes a series of endless and, as here shown, circular fuel grooves separated one from another by air spaces 56. As shown, the burner has an inner fuel groove 51 which forms the low-fire section of the burner and three other grooves 58 which together form the highfire section of the burner. There is a central air opening 59 in the base. The vertical side walls I of each groove 51 and 58 are flanged to receive a pair of the usual perforated combustion tubes I I between which a combustion chamber is formed in overlying relation with the groove. Air flows into each combustion chamber through the perforations in its tubes, such air being received from the space intervening between adjacent tubes of adjacent pairs and overlying the spaces 56 or from the central chamber overlying the opening 59. The construction is that usually used in burners of the perforated combustiorf tube type. The inner ring 51 is supplied with fuel at one or more points from the pipe l5. In starting the H burner up from a cold condition, the fuel supplied to groove 51 is liquid and a wick 50 is pro- 51 in normal operation.

The other grooves 58 are supplied with vaporiz'ed fuel from one or more vaporizing devices. In Fig. 5 of the drawings two such devices are shown, each including a hollow cylindrical hub El depending from the bottom wall of groove 51' and therefore kept warm by the fire which is continuously burning in such groove during normal operation. The lower end of hub 6| is closed by a plate 62, held in place bya nut 63 applied to the lower end of a stud 64 which is secured at its upper end to base IIJ. Plate 62 hasflxed thereto acylindrical sleeve 65 which extends upwardly within the hollow hub 6| in spaced concentrical relation therewith and terminates short of the upper end of the hub. An outlet pipe 66 for vapor is formed in the upper wall of hub 61 and this outlet is connected to one end of a cored passage 6! which is formed in base I0 and extends outwardly in underlying relation with the several grooves 58 and is connected to each by a port 68. The fuel supply pipe I6 is connected to hub 6! and fuel is admitted to the annular chamber 69. vaporization occurs here from the heated wall BI and normally all vaporization is effected here. However, in thetransition period,-'when a change is made from low to high fire,some vaporization occurs in the inner chamber 10 from the heated rod 64. During such period the temperature of wall 6| is relatively low and insufficient to vaporize oil at a rate equal to thatat which it flows into chamber 69. Hence, some oil will overflow into chamber 10 and be vaporized there. After the burner has been operating at high fire for a short interval, there is a substantial rise in the temperature of the base l0 and all parts connected thereto, and then wall 6| will be hot enough to vaporize oil as fast as it flows in and no oil will overflow into chamber 10.

The vaporized fuel fed into grooves 58' will find its way through cross passages 12 into the inner groove 51 and be ignited, the flame flashing back and igniting the vapor'in the grooves 58. Or ignition of the fuel vapor flowing into grooves 58 may be effected in any other suitable way.

In operation, combustion is maintained continuously in the inner groove 51 and the burner operates under a low fire, sufficient however to maintain the baselfl and the parts which are connected thereto, and which are relied on for effecting the vaporization function, at vaporizing temperature. Such temperature is subsequently increased when combustion occurs in all grooves of the burner, so that there is a minimum as well as a maximum vaporizing temperature to be considered. Now if the low fire control valve 49 is adjusted to allow the proper rate of flow of fuel to pipe l5 to supply the inner groove 51 to maintain a low fire of the desired proportions and is left in that position of adjustment at all times, we

having found out that there will be an excessive supply of fuel to that groove when the burner is operating at high fire, Hence, the purpose of the mechanism of Fig. 2 is to reduce the valve opening 48' when the high fire control valve 49 is opened. The reason why there is an excess supply of fuel to groove 51 on high fire, under the condition described, is that there is then an increased head of liquid effective to cause flow and since the head increases, the flow increases unless the valve opening is reduced. The level of fuel in chamber 35 remains constant at the level l-I which is above the bottom of groove 51. On low fire operation, vaporization occurs in pipe 15 and the oil therein drops to a certain level below the level ll. The difference between these levels is the effective head acting to cause fiow of oil through the orifice 49 and such flow will be constant. .'But when the temperature of base I!) increases,

as it does' when the burner is operating on high fire, the fuel will vaporize more rapidly and the oil in pipe l5 will drop to a lower level, giving an increased head and causing an increase in the rate of flow of, fuel to groove 51. To counteract for this increase in head,'the effective area of 'the outlet port 49' is reduced with the end in view of maintaining the fuel supply to groove 51 substantially the same on high fire as it is on low fire.

- u The invention has been disclosed herein, in an embodiment at present preferred, for illustrative purposes, but the scope of the invention is defined by the appended claims rather than by. the forelevel reservoir, a first conduit "connecting said reservoir and vaporizer for the gravity flow of fuel from the former to the latter, a first valve operable from the closed to the normally open position and controlling the flow through said first conduit, means for opening and closing said valve, a second conduit connecting said reservoir to at least one other of said grooves for the gravity flow of fuel from the reservoir to the last named groove, a second-valve operable from a partially closed position ,to the normally open positionand controlling the flow through the second conduit and means interconnecting said valves for simultaneous movement thereof,

whereby when said first valve is opened said second valve is moved to its partially closed position and vice versa.

2. A fuel control device for burners, comprising, a member having therein afuel reservoir with a fuel inlet thereto and first and. second fuel outlets therefrom, said first and second outlets adapted for connection to separate sections of the burner, an inlet valve to open and close said inlet, a float in said reservoir connected to .operate said valve, opening or closing it accordingly as the fuel in said reservoir falls below or rises above a predetermined level, a first outlet valve operable from the closed to the normally open position and controlling the flow through said first outlet, a second outlet valve operable from a partially closed to the normally open position and controlling the flow through said second outlet, and means interconnecting said outlet valves for, simultaneous movement thereof, whereby when said first outlet valve is opened the second outlet valve is moved to its partiallyclosed position and vice versa.

. RICHARD E. NEST.

DONALD'C. ELLIOT.

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