US3358928A

US3358928A - Cutoff valve for oil burner circuit

Info

Publication number: US3358928A
Authority: US
Inventors: Harold A Melendy
Original assignee: TRW Inc
Current assignee: Northrop Grumman Space and Mission Systems Corp
Priority date: 1965-11-08
Filing date: 1965-11-08
Publication date: 1967-12-19
Anticipated expiration: 1984-12-19

Description

Dec. 19, 1967 INVENTOR. Mea/ 0 ,42m/ue Megs/voy Hyg@ ATTORNEYS 2 Sheets-Sheet 2 H. A. MELENDY CUTOFF VALVE FOR OIL BUNER CIRCUIT Dec. 19, 1967 Filed Nov. 8, 1965 /fww United States Patent O 3,358,928 CUTOFF VALVE FOR OIL BURNER CIRCUIT Harold' A. Melendy, Royal Oak, Mich., assignor to TRW Inc., Cleveland, Ohio, a corporation of Ohio Filed Nov. 8, 1965, Ser. No. 506,650 Claims. (Cl. 239-111) ABSTRACT OF THE DISCLOSURE A control valve for regulating the ow of fuel oil between the cutoff point and the burner nozzle of an oil burner circuit and wherein iiow from the cutoff is open to the inlet after the ow has been cut off, thereby allowing any flow caused by compressed air expanding after pressure cut off to return to the burner pump inlet, instead of dribbling out of the nozzle into the rebox.

In ordinary oil burner circuits, the oil flow between the cutoff and the nozzle will have entrained air trapped in the coil. Since this flow is under pressure, the entrained air is compressed. Thus, when the flow is cut off and the pressure is reduced, the compressed `air will be allowed to expand. This expanding air forces a dribble of oil from the nozzle to go into the firebox.

In accordance with the principles of the present invention, a two-element cutoff valve is provided including inner and outer telescoping parts. In addition to regulating the ow of oil past a valve seat and through the valve to the nozzle, the inner and outer parts of the valve control a separate orifice which opens up the flow valve body to the inlet after the liow has been cut ofi by normal closure of the valve, thereby -allowing any flow caused by the compressed air expanding after pressure cut off to return to the burner pump inlet.

On the drawings:

FIGURE 1 is a somewhat schematic plumbing diagram of an oil burner circuit incorporating an oil burner pump having a cutoff valve incorporating the principles of the present invention;

FIGURE 2 is a fragmentary cross-sectional view taken on line II-II of FIGURE l; and

FIGURE 3 is a view similar to FIGURE 2 but showing the valve components in a different position.

As shown on the drawings:

In the oil burner circuit of FIGURE l, a fuel oil tank is shown generally at for containing a supply of fuel oil indicated within the tank and extending to a level 11. The tank 10 is supported on a frame 12 adapted to be carried on a support surface 13.

An inlet tube 14 has an inlet opening 16 near the bottom of the tank and is connected by means of a conduit 17 to an inlet tting 18 on one end of a boss 19 formed on the casing 20 of an oil burner pump.

The pump has a fitting 21 adapted to be connected to Aa by-pass conduit 22 for bypassing excess fuel back to the tank 10 through a by-pass outlet 23 at the end of the conduit 22.

Fuel at discharge pressure is supplied to a pump outlet fitting 24 connected to a discharge conduit 26 leading to an oil burner nozzle 27 adapted to atomize and project the fuel, as shown at 28, into a irebox for combustion.

Fuel at discharge pressure can also be used, if desired, to actuate a Warning alarm system in response to deviations from a reference pressure and to that end the pump is provided with a tting 29 connected to a conduit 30.

In order to accomplish the objectives of the present invention, the pump is provided with an integral boss 31 in which is formed the means for accommodating the cutoff valve of the present invention. Thus, referring to ICC FIGURES 2 and 3, it will be noted that the boss 31 has formed therein a cylindrical valve chamber 32 provided with a threaded opening 33 at one end in which is received the correspondingly threaded shank 34 of the fitting 24 and to which is connected the discharge conduit 26. A radial face 36 on the end of the shank 34 bottoms one end of a coil spring 37 and the other end of the coil spring 37 is bottomed against a radial face 38 of a spool valve shown generally at 39 and slidably disposed within the bore 32 for movement towards and away from a closure ball 40 pressed in firm assembly within a reduced diameter recess 41 formed at one end of the bore 32. The closure ball 40 effectively seals and closes a passage 42 interconnecting the bore 32 with a correspondingly shaped recess 43 in the other end of the boss 31 which, as noted previously, may be utilized, if desired, for connection to a warning alarm system via the connector 29 and the conduit 30.

A passage 44 is formed within the pump casing 20 and in the boss 31 and the passage 44 includes a leg 46 which is disposed radially with respect to the bore 31 to intersect the bore 31 at an inlet area 47.

The pump casing 20 in the boss 31 is further characterized by a by-pass passage 48 spaced from the

passage

44, 46 and having an opening 49 disposed at an intermediate portion of the bore 32,

In accord-ance with the principles of the present invention, the spool valve 39 has two components including inner and outer parts shown at 50 and 60, respectively.

The inner part 50 is a generally tubular member having a center bore 51 and yan enlarged headed portion at one end 52 through which the bore 51 opens, thereby to form -a radial shoulder 53. At the opposite end, the inner member 50 has a reduced wall portion which is reversely turned as at 54, thereby receiving and confining a ringshaped stop member 56 which provides .a nadial :abutment surface 57 projecting radially outwardly of the outer periphery of the inner v-alve member 50.

The outer valve part 60 is also a generally cylindrical member of somewhat shorter laxial or longitudinal length than the inner member and has a radial wall 38 at one end which engages the coil spring 37 and underlies the shoulder 53. At its opposite end there is a radial surface 61 which is engageable with the radial surface 57 of the ring stop member 56.

The outer valve part 60 has an inner through bore 62 sized to slidably receive the outer peripheral 4wall of the inner part 50. At the end of the bore 62 'adjacent the wall 61, a counterbore 63 is formed in which is received la coil spring y64 having its coils bottomed at one end against a radial shoulder 66 and having its coils bottomed at the other end against the radial wall 57 of the ring stop 56. Thus, a continuous biasing force is applied to the inner valve part 50 tending to orient the inner and outer valve j parts with respect to one another..

The outer valve part 60 is also provided with an outer peripheral recess adjacent the radial wall 61 which helps to form -an inlet area adjacent the opening 47. The recess 65 also results in the formation of a circumferentially extending radial shoulder 67 which together with the end wall 61 forms a surface against which pump discharge pressure is exerted tending to force the spool valve 39 towards an open position against the bias of the coil spring 37.

Referring specifically =to FIGURE 2, it will be noted that the reversely turned portion 54 o-f the inner valve part 50 forms a valve head which engages I'against the valve seat formed by the closure ball 40, thereby closing the iiow passage which is formed through the valve by the inner bore 51 of the valve assembly 39 and ythe bore 32.

The outer valve part 60 is also characterized by the formation in its outer periphery of a circumferentially extending recess 68 at an intermediate portion thereof, thereby leaving a land 69 and a land 70 on opposite sides thereof. The recess 68 is of longer longitudinal extent than the opening 48, thereby to insure communication therewith. A plurality of radial holes 71 extend through the outer valve part 60 and intercommunicate the bore 62 of the outer valve part with the recess 68.

The inner valve part 50 is formed with a plurality of smaller radial holes shown at 72 and which holes 72 extend between the inner bore 51 and the outer peripheral surface. Thus, when the valve is in the closed position of FIGURE 2, the holes 72 of the inner valve part 50 are in register with the holes 71 of the outer valve part and the interior of the valve assembly 39 is thus communicated with lthe inlet by-pass passage 48.

When the valve is moved to open position, the outer valve part 60 moves against the bias of the coil spring 37 and the inner valve part 50 is biased by the coil spring 64 towards the left using 4the orientation of FIGURES 2 and 3, thereby moving the holes 72 out of register with the holes 71 and discharge flow from the passage 44 passes past the valve seat provided by the closure ball 40 to the nozzle 27.

After flow has been cut oi by movement of the valve to a closed position, the holes 72 are again registered with the holes 71, as in the FIGURE 2 position of the valve, thereby allowing any ow caused by compressed air expanding after pressure cut off to return the oil to the inlet passage 4S and preventing the dribbling of oil through the nozzle 27 into the lirebox.

Although minor modifications might be suggested by those versed in the art, it should be understood that I wish to embody within the scope of the patent warranted hereon all such modifications as reason-ably and properly come within the scope of my contribution to the art.

I claim as my invention:

1. An oil burner circuit comprising,

a pump for pressurizing a supply of oil,

hydraulic conduit means for carrying the pressurized oil in the form of a stream,

a nozzle receiving the stream of oil for combustion,

and 4a valve in said conduit -means comprising a valve body having a through bore and an opening at one end of said bore for receiving the pressurized oil from said pump and discharging the oil to said nozzle at the opposite end of said bore, said valve body further including -a by-pass opening intermediate Ithe ends of said bore for communicating with a zone of lower pressure, means forming a seat in said bore at said one end, and a spool valve in said bore including inner and outer tubular parts slidable in said bore and slidable with respect to each other,

said outer part having an annular recess and a radial opening communicating therewith for registry with said by-pass opening at all positions of said valve, said inner part having radial openings movable into and out of registry with said radial opening of said outer part, a loading spring bottomed against said outer tubular part and urging said spool valve closed,

said inner part being slidably mounted in said outer part and being longer in length than said outer part,

thereby to form a valve head for eng-aging said seat, said inner valve part having radially outwardly extending 4abutments limiting the relative movement of said parts,

and spring means between said inner and outer valve parts normally biasing said parts to move said radial openings out of registry when said spool valve is open and yieldable to move said radial openings into registry when said spool valve is closed,

thereby venting the interior of the valve after shut-off to prevent dribbling through the nozzle.

2. A valve for controlling oil ow between the cut-off and the nozzle in an oil burner circuit comprising a valve seat,

a movable hollow spool valve having an annular closure head engaging said seat to open and control a flow passage extending past said seat and through the hollow interior of said spool valve.

and means including said spool valve forming a valve controlled relief passage which is opened in response to movement of said spool valve towards said seat to vent any compressed air trapped in said valve after closure,

thereby to prevent forced dribble of oil from the nozzle after closure of the valve.

3. A cutoff valve for an oil burner circuit comprising,

valve body means forming a bore through which oil in said circuit is discharged to a burner nozzle at one end and having a valve seat at the opposite end,

an intermediate by-pass opening into said bore,

and a two-piece spool valve including an inner part having a through bore and an annular valve head engageable with said seat to open and close said circuit,

and an outer part slidable in said bore,

said inner and outer parts having intermediate apertures formed therein adapted to mate with said by-pass opening when the valve is closed to vent the circuit after cut oil.

4. A cutoff valve as defined in claim 3 and further characterized by said inner valve part being longer than said outer valve part and having a generally tubular body formed with a reversely turned end to provide said annular valve head.

a ring stop surrounding said inner part and engaging against said reversely turned portion,

and a spring engaging said ring stop and engaging against said outer part.

5. A cutoff valve as defined in claim 4 and further characterized by said inner valve part having a headed portion forming a radial `abutment surface overlying said outer part thereby to limit the relative movement between the parts.

References Cited UNITED STATES PATENTS 1,731,806 10/1929 Aldrich 239-111 2,248,395 7/1941 Taper et al. 158-36 2,695,662 11/1954 Hagelin et al. 239-126 X 2,837,148 6/1958 Jay 158-36 2,915,015 12/1959 Erikson et al. 158-36 3,246,663 4/ 1966 Jakowchuk 137-102 FOREIGN PATENTS 722,878 2/1955 Great Britain.

M. HENSON WOOD, JR., Primary Examiner.

VAN C. WILKS, Assistant Examiner.

Claims

2. A VALVE FOR CONTROLLING OIL FLOW BETWEEN THE CUT-OFF AND THE NOZZLE IN AN OIL BURNER CIRCUIT COMPRISING A VALVE SEAT, A MOVABLE HOLLOW SPOOL VALVE HAVING AN ANNULAR CLOSURE HEAD ENGAGING SAID SEAT TO OPEN AND CONTROL A FLOW PASSAGE EXTENDING PAST SAID SEAT AND THROUGH THE HOLLOW INTERIOR OF SAID SPOOL VALVE AND MEANS INCLUDING SAID SPOOL VALVE FORMING A VALVE CONTROLLED RELIEF PASSAGE WHICH IS OPENED IN RESPONSE TO MOVEMENT OF SAID SPOOL VALVE TOWARD SAID SEAT TO VENT ANY COMPRESSED AIR TRAPPED IN SAID VALVE AFTER CLOSURE, THEREBY TO PREVENT FORCED DRIBBLE OF OIL FROM THE NOZZLE AFTER CLOSURE OF THE VALVE.