US2496214A

US2496214A - Pilot fuel flow control

Info

Publication number: US2496214A
Application number: US544055A
Authority: US
Inventors: Roy W Johnson
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-07-08
Filing date: 1944-07-08
Publication date: 1950-01-31
Anticipated expiration: 1967-01-31

Description

Jaim EL X95@ m, W, JQHNSQN ZQ PILOT FUEL FLOW CONTROL Filed July $3, 1944.

INVENTOR. E05/ W Joy/VSGA! Patented Jan. 31, 1950 y y y 2,496,214

UNITED STATES PATENT yOFFICE:

Roy W. Johnson, Milwaukeatwis.

Application J uly 8, 194.4, feral No. 544,0;55

This invention relates to improvements in devicesior controlling the flow of fuel oil from a reservoir to a burner of the gravity feed type and particularly to means controlling the supply of oil to the pilot flame of such burner.

Devices of the character to which the present invention relates are known to the art as shown for example in Patent 2,120,364, issued to Roy W. Johnson on J-une 14, 1938. In such devices an inlet valve `actuated by a oat controls the iiow of oil to maintain a substantially constant level of oil `in a chamber. Oil ows from the chamber to one or more burners under the control of a metering valve or valves adjustable manually and/ or thermostatically. y

A pilot flamemust be kept constantly burning to provide for ignition of the oil supplied to the main burner so that oil must be constantly suppliedto the` pilot flame regardless of the 'position` of the valve for metering the flow `of oil to the main burner. The volume of oil nowing to the burner is varied by temperature changes or changes in the composition of the oil itself and means must therefore be Iprovided :for adjusting the flow of fuel to the :pilot to compensate for such changes. A passage o f relatively smallcross sectional area can be used to controlthe ow of provide means which may be readily adjusted tot compensate for changes in the flow Aof oil to the pilot name or burner of an oil burner.

. Another object of!l the presentinvention isito provide a device for =cor'itrolling vthe flow of [fuel o il to a pilot flameorlpilot burnerto secure the I desired volume of oil regardless of changesV in the characteristics of the oil. gw.

Another object of the invention is to tcontrol sectional area, or sci-called capillary passage, of which the effective length may bereadily adjusted and which may easily b e `kept free from materials depositingifrom the oil.

Another objectof the invention is to provide a capillary passage for controlling the now of oil to a burner for pilot operation in which a part of` the means forming the Ipassage may removed ,i

for cleaning without disturbing adjustment-oi the device for either its control of flow for main flame `or 'pilot flame W operation I- of the .burner.` .l .I i Objects and-advantages other than those aboven set `f ort1iwill pibe.. apparent *from` xthe` following.

I 9 Claims. (Cl. 137;-21) i i i the flow of oil during pilot .operation of a burner.

by means of a passage of relatively small cross-` 2 description when read in connection with the accompanying drawings, in which:

Fig. 1 is a top plan view of a constant level oil control device embodying the present invention with all of the parts not essential to disclosure of the present invention omitted therefrom;

Fig. 2 is a vertical cross-sectional View taken on the plane of the broken line II-II of Fig. 1;

Fig. 3 is a vertical sectional view taken on the plane of the line III-III of Fig. 2;

Fig. 4 is an enlarged fragmentary View of 'the structure forming a capillary ypassage between the casing chamber land a portion of the outlet passage therefrom, in a constant level oil flow control device; and

Fig. 5 is a vertical sectional View similar to that i shown in Fig. 3 but illustrating a modified embodiment or" the present invention.

Referring more particularly to the drawings by characters of reference, numeral II designates a casing -divided substantially into a main chamber I2 and an auxiliary chamber I3 by a partition or ydarn I4 having its crest slightly above the normal level of the oil to be maintained in 'the main chamber. The casing is formed with ears I5 for attachment thereto of a cover I6 by suit--` .able means such as screws I 1. A fuel supply conduit 20 is preferably formed integral `with the casing I I and is provided with a nipple 2| by which a pipe connection with a reservoir for fuel (not shown) may be made. The conduit 20 is adapted to receive a suitable filter such as is shown for example in the above patent.

An opening is formed in a thickened portion 23 in the wall between the main chamber I2 and the conduit 2D and is internally threaded to receive a valve casing or body 24 which is formed with an axial Ipassage and transverse passages providing for communication between the conduit I and the chamber I2 under the control of a valve 25. The valve 25 is preferably formed as a needle having va beveled end seating on a shoulder 26 formed inthe valve body 24 and preferably adjacent the vjuncture of the axial and transverse passages therein. The valve 25 controls the ow of fuel oil from the cond-uit 20 in such manner as notch 29 inthe dam I4 into the auxiliary cha-mf ber I3 to-release a latch mechanism disclosed in` the above identied patent, `which positively closes the inlet valve 2 5.- I

The casing II is provided with a passage 3| terminating in nipples 32 and"Sato-whichpipes vmay be connectedforfseverally supplying fuelgoil toaiburnerorburners (not shownl-l--I It-willbeunderstood that when only one burner is to be supplied, the nipple not used is closed by a suitable plug. A valve casing or body 3d is inserted in one end of passage 3| and is formed with both axial and transverse 'passages through which oil may flow `under the control of a valve 35. The valve seats on a shoulder 36 formed in the valve body 34 and is formed with a tubular portion 3l extending beyond the seat and Iprovided with slots 38 for the purpose lof allowing precise metering of the quantity of oil suppiied to the main burner. The valve 35 has mounted thereon a collar 39 havin-g a ringer 40 extending therefrom and engaged between guide ribs 6I on a `wall of casing I I.

- Fuel is supplied for pilot operation of the main burner 'from the main chamber. l2 .by Way of a conduit lay-passing the metering. valve 35 and iiows through such lay-pass independently of the action of the metering valve 35. As Shown in Fig. 3, a well is formed in one side of the casing I and is connected at its lower end with the outlet passage 3l beyond the outlet valve seat 35 by tubing 4l. It will be seen from the drawings that the well i5 is within the main chamber i2 of the device and that oil may accordingly flow through such well and the tubing 47 to the outlet passage 3| except as such flow is controlled by a plug having a portion 5G and a portion 5|'. The plug portion 5D seats in the well 46 and blocks off ilow of oil therethrough except for such oil as may ovv through a groove on the plug portion 5% and extending from the upper edge of the well to the lower end of the plug portion. The groove in the plug portion 50 is shown as being formed by a'relatively coarse thread 52 which fits closely into thel well d6 so that the outside diameter of the thread in cooperation with the Wall of the Well deiines a passage of relatively small crosssectional area or a capillary passage which allows flow of oil from the chamber I2 through the well G6 at a rate dependent on the effective length of the passage, that is the length of the thread which is within the well itself.

The plug portion 5| is of less diameter than the plug portion 5i) and is threaded to engage with an adjusting nut seating on the wall forming the well 45 and forming a seat for one end of a compression spring 56 having its other end seated on the shoulder formed by the juncture of the plug portions 5b and 5|. Rotation of the 'nut -55 is limited byl a pin 5l extending from the nut and engaging with al rib 53 on the casing side wall. Theposition of the plug 59-5i in the Well 46 is adjusted by rotation of the plugin the nut byineans o'i` a suitable tool engaging the slotted upperend of the plug through liole in the Acover I6, which is normally closed by a but-V ton 6l). Rotation of the plug is limited by a collar 62 which is threaded on the plug portion or stem 5| and contacts on the nut 55 when the plug is in position to secure the maximum eliective length of the capillary passage. The collar 62 has an ear engaging a stop 63 to limitrotation of the collar. The entire plug is held in adjusted position by a springtil seatedbetween a shoulder on the plug stem 5| and the cover it. The plug 55-56 is formed with an axial passage therethrough to vent any gas released from the oil in the capillary by-pass and thus prevents so-called binding of the by-pass.

In the use of the device, oil flows from the chamber I2 beneath a portion of the nut 55 and enters the capillary passage defined by the thread 52 and the wall of the Well 45. Oil ows downwardly through the capillary passage, as indicated by the arrows, into the Well e6 and thence through the tube II'I to the outlet passage 3|. The amount of oil owing through the above path is determined by fluid friction on the Walls and hence by the length of the capillary passage which is readily adjusted merely by turning the plug to increase or decrease the length of the groove formed by the thread Within the Well. If the capillary passage becomes partially or wholly clogged, removal of the cover I6 and the spring 64 allows the plug Sil- 5l to be lifted out of the Well '46 for cleaning. It Will be seen that the entire area and length of the capillary passage is then exposed and can be thoroughly cleaned. Ifcare is taken that the nut is/not turned dur-Y ing the cleaning operation, replacement 0i the cleaned plug in the Well with the pin 5l' between the rib 58 avoidsany necessity for readjustments not required by temperature or oil composition changes.

The structure shown in Fig. 5 is generally similar to and functions in a manner generally similar to that shown in Fig. 3 excepting that the oil flows upwardly through the capillary passage. In the modified structure, a Well 66 is formed with aninlet @l and an outlet 68. A solid plug with portions Se and l@ is provided on its portion 69 with a coarse thread 7| tting into the well and, in combination with the Well, denes a capillary passage of'which the effective length may oe determined by positioning the plug portion e9 relative to the outlet 68. An adjusting nut l2 is threaded on the plug stem portion 'I0 and engages a locking bar 'I3 which is preferably guided in its movements by ribs 'M on the casing Wall. A lock Washer 'I5 contacts both the nut 'l2 and the locking bar 'I3 and prevents accidental movement of the plug under the influence of a spring i6 between the nut and the cover. The oil flowing through the capillary passage is discharged into a sump 'il' formed in the casing adjacent the well 66 and from there flows through Y the sump outlet 'I8 into the casing outlet passage 3|.

It will be seen that the present invention provides a structure in which a capillary passage bypasses the main flame ow control valve for a liquid fuel burner, thus providing for continuous flow of fuel to the burner during the pilot portion of its cycle. ends ci the capillary passage are both below the level of the fuel maintained in a supply chamber so that the volume of fuel flowing through the passage is variable merely by varying the eiiective length of the passage. Such variation is obtained merely by adjusting they position of a grooved plug in a well, both the plug and the Wall of the well being required to define the capillary pas- The position of the plug is readily adjust-g entire area and length of the groove for maintenance of the initial cross-sectional area andthe original frictional characteristics of the groove Wall. And the plug is readily replaced without disturbing the adjustment of the metering valve or change in the setting of the 'by-pass.

Although but two embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modincations may'bemade therein without' departing from the spirit of the The inlet and the discharge invention or from the scope of the appended claims.

I claim:

1. In a device controlling the iiow of liquid fuel to a burner of the gravity feed type, a casing having a fuel supply chamber provided with an outlet passage and a well connected with the chamber and the passage, and a plug mounted in the well for axial movement therein and denning with a portion of the wall of the well a capillary passage therewith for maintaining a continuous and limited ow of fuel to the burner, and means for axially adjusting the plug within the well to vary the effective length of the capillary passage.

2. In a device controlling the flow of liquid fuel to a burner of the gravity feed type, a casing having a chamber with an outlet passage therefrom and a well connected between the chamber and the passage, and a plug mounted in the well and having a groove coacting with the wall of the well to dene a capillary passage for maintaining a continuous flow of fuel to the burner and means for adjusting the plug axially of the well to bring portions of the groove into and out of the path of liquid now through the well.

3. In a device controlling the ow of liquid fuel to a burner of the gravity feed type, a casing forming a fuel supply chamber with an outlet passage therefrom and a well connected between the chamber and the passage and by-passing a portion of the passage, a plug mounted in the well and having a helical groove coacting with the wall of the well to define a capillary passage for maintaining a continuous flow of fuel to the burner. and means for axially adjusting the position of the plug in the well to vary the length of the capillary passage in the path of liquid iiow through the well.

4. In a device controlling the flow of liquid fuel to a burner of the gravity feed type, a casing defining a chamber and an outlet passage therefrom and a Well connected with the chamber and the passage, a plug having a groove coacting with the wall of the Well to define a capillary passage for maintaining a continuous ilow therethrough of fuel from the chamber to the passage and to the burner, a spring biasing the plug into the well, and means for limiting the action of the spring and adjustable to vary the position of the plug in the well.

5. In a device controlling the ilow of liquid fuel to a burner of a gravity feed type, a casing deiining a chamber and an outlet passage therefrom and a well connected with the chamber and the passage, a plug having a groove coacting with the wall of the well to define a capillary passage for maintaining a continuous iiow of fuel therethrough from the chamber to the passage and to the burner, the plug being movable axially within the well to vary the capillary effective length of the passage, means urging the plug into the well, and means limiting movement of the plug by the first said means.

6. In a device controlling the flow of liquid fuel to a burner of a gravity feed type, a casing delining a chamber and an outlet passage therefrom and a well connected with the chamber and the passage, a plug mounted within the well and having a helical groove extending from end to end of the plug and coacting with the wall of the well to define a capillary passage for maintaining a continuous flow of fuel therethrough from the chamber to the outlet passage and to the burner, a

spring acting along the longitudinal axis of the plug and urging the plug into the well, and means limiting movement of the plug by the spring and adjustable to vary the length of the groove in the path of liquid flow through the well.

7. In a device controlling the flow of liquid fuel to a burner of the gravity feed type, a casing having a well between a supply chamber and an out let passage, the wall defining the well having vertically spaced inlet and outlet apertures therein connecting the well with the chamber and the outlet passage respectively, a plug in the well for defining a capillary passage therewith between said inlet and outlet apertures to maintain a continuous ow of fuel to the burner, and means for axially adjusting the position of the plug in the Well to bring an intermediate part of the passage defining a portion of the plug into alignment with a controlling one of said apertures to thereby vary the effective length of the capillary passage below said controlling well wall aperture and in the path of liquid flow through the well.

8. In a device controlling the flow of liquid fuel to a burner of the gravity feed type, a casing having a well between a supply chamber and an outlet passage, the well wall having vertically spaced inlet and outlet apertures therein connecting the well with the chamber and the outlet passage respectively, a plug having a groove coacting with a wall of the well for defining a capillary passage between said inlet and outlet apertures to maintain a continuous flow of fuel to the burner, and means for axially adjusting the position of the plug in the well to bring an intermediate part of the groove into alignment with a controlling one of said apertures to thereby vary the effective length of the capillary passage below said controlling well wall aperture and in the path of liquid ow through the well.

9. In a device controlling the flow of liquid fuel to a burner of the gravity feed type, a casing defining a chamber and an outlet passage therefrom and a well bypassing a portion of the outlet passage, the well wall having vertically spaced inlet and outlet apertures connecting the well with the chamber and the outlet passage respectively, a plug in the well and having a groove coacting with a Wall of the Well to define a capillary passage between said inlet and outlet apertures for maintaining a continuous flow of fuel to the burner, the plug being adjustable axially in the well to bring portions of the groove above a controlling one of said apertures in the well wall to thereby vary the effective length of said capillary passage between said inlet and outlet apertures, the plug having a passage vertically therethrough for venting gases from the liquid owing through the well, a spring urging the plug toward the bottom of the well, and means limiting movement of the plug and adjustable to vary the plug position in the well.

ROY W. JOHNSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,858,557 Platt May 17, 1932 2,012,004 Hall Aug. 20, 1935 2,355,870 Johnson Aug. 15, 1944