US3402891A

US3402891A - Furnace pump and oil burner circuit

Info

Publication number: US3402891A
Application number: US481366A
Authority: US
Inventors: Hubert M Clark; Gilbert H Drutchas; Becker Philipp
Original assignee: TRW Inc
Current assignee: Northrop Grumman Space and Mission Systems Corp
Priority date: 1965-08-20
Filing date: 1965-08-20
Publication date: 1968-09-24
Anticipated expiration: 1985-09-24
Also published as: DE1553248A1; FR1464360A; GB1132590A

Description

Sept 24, 1968 H. M. CLARK ETAL FURNACE PUMP AND OIL BURNER CIRCUIT 5 Sheets-Sheet l Filed Aug. 20, 1965 www.

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INVENT0R5 #05527' /14 (242K 64 55er H @farm/4s PAUL /Pp sczee BY@ LQ ATTORNEYS .v I y Sept 24, 1958 H. M. CLARK ETAL 3,402,891

FUHNACE PUMP AND OIL BURNER CIR-CUIT Filed Aug. 2C, 1965 5 Sheets-Sheet Z INVENTORS #055er /l/. 24e/K 6M 55er A( @earn/4s @am /PP 55cm/e2 BY@ ATTORNEYS sept. 24, 1968 Filed Aug. 20, 1965 H. M. CLARK ETAL 3,402,891

FURNACE PUMP AND OIL BURNER CIRCUIT 5 Sheets-Sheet.l 3

. INVENTORS /c/fer M 6242K GM 55er A @ez/rams A// /PP EcKER ATTORNEYS Sept- 24, 1968 H. M. CLARK ETAL 3,402,891

FURNACE PUMP AND OIL BURNER CIRCUIT INVENTORS /z/fe //Z C4421( GM 5627' A( Deuren/4s /D /L /Pp BECA/52 Hyg@ M @1494/ ,a ATTORNEYS SePf- 24, 1968 H. M. CLARK ETAL 3,402,891

FURNACE PUMP AND OIL BURNER CIRCUIT v Filed Aug. 20, 1965 5 Sheets-Sheet 5 INVENTORS 05527- /l/f. 624,61(

G/L saar Deuren/As f4/L /Pp 55C ze@ *l ATTORNEYS United States Patent O 3,402,891 FURNACE PUMP AND OIL BURNER CIRCUIT Hubert M. Clark and Gilbert H. Drutchas, Birmingham, and Philipp Becker, Utica, Mich., assignors to TRW Inc., Cleveland, Ohio, a corporation of Ohio Filed Aug. 20, 1965, Ser. No. 481,366 7 Claims. (Cl. 239-127) ABSTRACT OF THE DISCLOSURE A11 oil burner circuit characterized by a furnace pump utilizing a pivoted pump ring forming a pumping chamber for a double stage slipper pump wherein slippers rock angularly and move radially in following' the contour of an adjoining inner wall of the pump ring so that pivotal adjustment of the pump ring will vary the displacement and thereby the output of the pump in direct proportion to the eccentricity for maintaining a given pressure drop across a fixed orifice nozzle while minimizing by-pass ow.

In an ordinary oil burner circuit, the ow output of a furnace pump is usually controlled by a relief and bypass valve. After the fixed orifice nozzle is satisfied, the excess output of the pump is by-passed and dumped. However, in acting on the liquid through the pumping operation, energy is expended because work is being performed.

In accordance with the principles of the present invention, a slipper-type pump is provided wherein one or more slippers carried in a rotatable rotor are free to move radially and to rock angularly in following the contour of 'a pumping bore formed in the center of a pivoted pump ring which is infinitely adjustable within the range of geometry of the pumping mechanism. Adjustment of the pump ring will vary the displacement and thereby the output of the pump in direct proportion to the eccentricity. Such adjustment will permit the operation of the oil burner circuit with the minimum displacement necessary to maintain a given pressure drop across any fixed orifice nozzle with no excess to be dumped.

By virtue of the provisions of the present invention, ya different orifice size can be easily changed and adjusted so lthat the pressure drop of the new orifice would again be whatever the requirement might be for the new condition. The by-pass oil for normal operation is therefore zero at all times.

Should the fixed orifice nozzle be plugged for any reason, then the oil would be by-passed and a flow or pressure-sensitive alarm system can be connected into the by-pass to indicate such plugged condition of the nozzle.

It is an object of the present invention, therefore, to provide yan adjustable slipper pump wherein a pivoted pump ring can be adjusted to vary the displacement and thereby the output of the pump in direct proportion to the eccentricity of the ring.

Another object of the present invention is to provide an oil burner circuit wherein the pump is readily adjustable for matching to the fixed orifice nozzle.

Yet another object of the present invention is to provide an oil burner circuit wherein by-passing is substantially eliminated or minimized.

A still further object of the present invention is to provide a double staged slipper pump wherein the pumping chamber is formed by a pivotally mounted pumping ring infinitely adjustable 4to vary the displacement and thereby the output of the pump and wherein the capacity of the double stages is selected to afford optimum operating conditions.

Many other features, advantages and additional objects ICC of the present invention will become manifest to those versed in the 'art upon making reference to the detailed description which follows and the accompanying sheets of drawings in which a preferred structural embodiment of an oil burner circuit and a furnace pump is shown by way of illustrative example.

On the drawings:

FIGURE 1 is a somewhat schematic plumbing diagram but showing an oil burner circuit utilizing a furnace pump provided in accordance with the principles of the present invention;

FIGURE 2 is an elevational view of the furnace pump per se;

FIGURE 3 is a cross-sectional view of the pump of FIGURE 2 taken substantially on line III-III of FIG- URE 2;

FIGURE 4 is `an end elevational View of the pump shown in FIGURES 2 and 3;

FIGURE 5 is a cross-sectional view taken on line IV IV of FIGURE 4;

FIGURE 6 is a cross-sectional view taken on line VI- VI of FIGURE 4; and

FIGURE 7 is a cross-sectional view taken on line VII--VII of FIGURE 4.

As shown on the drawings:

Referring, first of all, to FIGURE 1, an oil reservoir tank is shown generally at 10 and is supported by a stand 11 on a supporting surface 12. The tank 10 is shown filled with a supply of fuel oil to a level 13 and an inlet tube 14 has an open end 16 located near the bottom of the tank. The inlet tube 14 is connected by means of a conduit 17 to a furnace pump shown generally at 18. In the form of the invention illustrated, the pump 18 comprises a socalled slipper pump wherein a plurality of slippers carried in a rotor are free to move radially and to rock angularly in following the adjoining wall of a pumping chamber or pumping bore. Thus, the slipper pump can advantageously provide -two separate pumping circuits including an outer circuit and an inner circuit, which two circuits may be staged. As shown in FIGURE 1, the pump 18 has an inlet 19 and the fluid after entering the pump 18 passes through a strainer assembly shown generally at 20, whereupon the fluid enters a rst stage intake designated at 21.

After initial pressurization, the fluid is brought out of a rst stage discharge 22 and any excess fluid enters a by-pass 23 under the regulation of a by-pass control valve 24. For a two-pipe system with a return to the reservoir tank 10, there is provided in the pump 18 a passage portion 26 in which is pressed a ball 27 so that a conduit 28 connected to the tting 26 will discharge the by-pass to a return tube 29 entering the tank 10 and discharging the Iby-passed uid as at 30 above the level of the liquid 13 near the top of the tank 10.

Fluid acted upon by the first stage then enters a second stage intake shown at 31 and when the fluid is additionally pressurized, it is discharged from 4the second stage discharge 32 where it is directed through a conduit or passage 33 towards -a point of utilization which, in the case of an oil burner circuit, constitutes a fixed orifice nozzle shown at 34. A pressure regulating Iand shut-olf valve is shown at 36 in the discharge line.

As will be evident from an inspection of the pump as shown in FIGURE 1, a pumping chamber is provided by a pump ring 37 pivoted on an axis 38 and the pump ring 37 is adjustably pivoted within a housing 39 by setting a pair of diametrically opposed

eccentricity adjustment screws

40 and 41 which constitute a locking screw means.

Bypivoting the pump ring 37 at the axis 38, the pump ring 37 can be adjusted in such a manner that the center of the rotor and the center of the pump ring 37 coincide or are separated by an infinitely adjustable amount within the range of the geometry of the pumping mechanism. This adjustment will vary the displacement and thereby the output of the pump in direct proportion to the eccentricity. That adjustment will permit lthe operation of the oil burner circuit with the minimum displacement necessary to maintain -a given pressure drop across any given orifice at 34 with no excess to be dumped. If desired, the system can be easily changed to a different oritice size and adjusted so that the pressure drop of the new orifice would again be whatever the requirement might be for the new condition. The by-pass oil for normal operation is therefore minimized.

In considering the oil burner circuit as a whole, in connection with the description of FIGURE l, it will be noted that the pump 18 has a portion shown generally at 42 included in the discharge line. A reduced neck 43 is provided in which is pressed a closure ball 44. There is thus formed a second discharge area 46 connected by means of a conduit or passage 47 to the second stage discharge 32 and a fitting 48 is provided by means of which the 4system may be connected to a suitable warning signal. The Warning signal could either be ow or pressure sensitive, thereby indicating a plugged nozzle or other adverse operating condition.

Referring now to the additional structural details of the pump 18 shown in conjunction with FIGURES 2-7, the pump 18 is shown as comprising an outer casing 39 and a cover 50 is provided through which projects a shaft 51 adapted to be connected to a suitable source of power at the flattened portion 52. The casing 39 and the cover 50 are retained in firm assembly with one another by a plurality of fasteners 53.

As shown in FIGURE 3, the casing 39 is provided with a pair of threaded openings 54 `and 56 in which are received the

eccentric adjustment screws

41 and 40. The screws 40 and -41 are each provided with slotted ends for cooperation with a suitable adjustment tool such as a screwdriver and protection caps may be provided as at 57 which have threaded apertures 58 thereby to effect a threaded-together assembly With each corresponding adjustment screw and a sealing gasket 59 is interposed between the casing 39 and the cap 57 to provide a sealed joint and thereby prevent leakage.

The pump ring 37 has an outer peripheral surface 60 and an inner bore 61 forming a pumping chamber. Rotatably received within the bore and driven by the shaft 51 is a rotor 62. The rotor 62 is provided with a plurality of notches 63 each characterized by a bottom Wall 64 and side walls 66 and 67.

A slipper indicated generally at 68 is provided for each notch 63. Each slipper has a curved outer sealing surface 69 which is contoured to be complementary to the bore Wall 61. The slipper sealing -surface being of a slightly smaller radius than the bore wall, contact between the surfaces will be, in effect, a land contact.

At one side of the slipper 68, there is provided an end Awall which is notched to receive a sealing means shown generally at 70. By virtue of such sealing means, the pump is particularly adapted to develop a dual pumping action characterized by the provision of inner and outer pumping circuits. Thus, the pump is suitably ported with inlet and outlet ports communicating with a working chamber 71 formed between the bore wall 61 and the outer peripheral surface of the rotor 62 so that a first pumping circuit will be established outwardly of the sealing means. Additionally, the pump is ported to communicate with the inner portions of the notches 63, thereby to establish `a second pumping circuit inwardly of the sealing means 70. The sealing means 70 is energized by the action of centrifugal force upon rotation of the rotor 62, thereby effecting a good sealing -action between the slipper 68 and the adjoining `wall 67 of the rotor 62.

In order to provide an additipnal outward loading of each slipper 68, there is provided a coil spring 72 for each slipper which is bottomed against the bottom wall 64 0f each corresponding notch and against the corresponding slipper.

It will be understood that the first stage intake 21 and the first stage discharge 22 communicate with the working chamber 71 while the second stage intake 31 and the second stage discharge 32 communicate with the inner portions of the notches 63.

The capacity of the outer circuit is preferably arranged to be in excess of the inner circuit, thereby giving a supercharging action for the second stage and any excess will be by-passed back to the fuel tank. The control of the circuit capacity is effected by properly proportioning the vane sections with respect to the relative eccentricity and width relationship so that the width of the slipper 68 and the corresponding notches 63 may be adjusted to correspondingly vary the capacities of the inner and outer pumping circuits.

Referring to FIGURE 6 in connection with FIGURES l, 2 and 4, a strainer clean-out plug is shown at 76 and is threaded into a correspondingly threaded opening 77 formed in the casing 39 in cooperation with a gasket 78 in order to afford ready accessibility to a removable strainer shown generally at 20. The strainer 20 includes a retainer bowl 79 which is of cup-shaped configuration and has side walls engaged by an O-ring gasket 80 carried in a circumferentially extending groove 81 formed in an opening 82 of an end plate 83. The retainer bowl 79 has an embossed end wall as at 83 which bottoms and retains a generally tubular forarninous screen 84 which functions as a filter element in straining all of the fuel drawn into the pump from the fuel tank 10.

The end plate 83 has an outer peripheral groove 84 in which is received an O-ring sealing member 86 which engages and seals against the inner surface 87 of the casing member 39, thereby dividing the interior of the casing 39 into two separate zones on opposite sides of the lsealing member 86.

The end plate 83 constitutes one part of a stack-up which includes a porting plate 90 and a backing plate 91 in addition to the pump ring 37 and the rotor 62. The entire stack-up is placed under an initial compressive load by means of a plurality of coil `springs 93 which are spaced circumferentially and each has one end bottomed against the end Wall of the casing 39 and the other end bottomed in recesses 94 for-med in a motive surface 96 constituting one face of the end plate 83.

As shown in FIGURE 7, one of the recesses 94 is eX- tended through the end plate 83 and is formed with a valve seat 97 seating the ball valve 24 which regulates the by-pass ow back to the fuel tank 10. In FIGURE 7, it will be noted that the ball valve 24 is continuously biased by a coil spring 98 bottomed against a shoulder 99 formed to extend circumferentially around a passage 100 in the porting plate 90. The passage 100, in turn, communicates with a through passage 101 formed in the pump ring 37 from whence the fiuid flows through a passage 102 formed in the backing plate 91 and to a passage 103 formed in the cover 50. The passage l103 corresponds to the conduit 23 shown in FIGURE 1 and may be connected with a suitable return line in a twopipe system by means of a nipple connector 104 (FIG- URE 4).

As described in connection With FIGURE l, the fitting 26 constitutes the cover portion 50 of the pump and at the end opposite the nipple connection 104, there is provided another nipple connector 106 by means of which the conduit 17 may be connected to communicate the pump with the fuel tank 10 and the inlet tube 14. Thus,

as shown in FIGURE 6, the inlet formed in the cover 50 is again designated at 19 and communicates inlet fiuid through a passage 107 and into an inlet 108 surrounding the pump ring 37 as well as the backing plate 91, the porting plate 90 and portions of the end plate 83. The

inlet fluid passes through the strainer 84 and then through an inlet port 21 formed in the porting plate 90 for communication with the working chamber 71 of the first stage or outer pumping circuit. After being acted upon in 4the working chamber 71, the iiuid at an intermediate pressure is directed to a zone at intermediate pressure between the end wall of the casing 39 and the motive surface 96 of the end plate 83.

The liuid at intermediate pressure tends to pressure load the motive surface 96, thereby assisting in keeping the stack-up of parts clamped together for improved pumping etiiciency without requiring any special clamping means or other mechanical assistance.

From the space behind the motive surface 96, the fiuid passes through the end plate 83 via a passage 109 and passes through the porting plate 90 via a passage 110 to a second stage intake 22. The iiuid is then acted upon in the second stage and is discharged out of the second stage discharge 32. As shown in FIGURE 6, the end -plate 83 has a through opening 112 in which is slidably received the Valve member 36. The valve member 36 is generally cup-shaped in configuration having side Walls 113 forming a recess in which is bottomed one end of a coil spring 114. The opposite end of the coil spring 114 is engaged against a pressure adjustment screw 116 retained in a nut 117 threaded into the end Wall of the casing 39 and enclosed by a closure cap 1'18. The valve 113 has a reduced end portion 119 which carries a rubber sealing gasket 120. There is provided a passage 8S formed in the end plate 83 which is normally closed by the side walls of the valve member 36, however, if the valve 36 opens sutiiciently to expose the passage 85, it will act as a relief or by-pass passage to direct fluid at outlet pressure back to the low pressure inlet zone 108.

A hollow pivot pin 121 is carried by the porting plate 90 in an aperture 122 and extends through an aperture 123 in the pump ring 37, thereby to form a pivotal support for the pump ring 37 and establishes the pivot axis 38. The pivot pin 121 extends into the interior bore 124 of a tubular member 126 which extends into an opening 127 formed in the backing plate 91. The member 126 also extends into a passage 128 communicating with a passage identified in FIGURE 1 at 33 and constituting an outlet passage in the pump which may be communicated to a point of utilization via an outlet nipple fitting 129.

A center passage 130 is formed in the hollow pivot pin 21 and is engaged by the sealing gasket 120 so that the valve 36 operates as a regulating Ishut-off Valve. The surfaces of'the valve 36 exposed to the discharge pressure and thestrength of the spring 114 are proportioned and selected so that' the pressure regulating and shut-off valve 36 will operate through a normal operating range. ln the view of FIGURE 6, the valve 36 is shown fully closed while in the lsomewhat schematic view of FIGURE 1, the valve is shown fully open.

To insure good sealing of the inlet area 108, the cover 50 is provided with a peripheral groove 131 receiving an O-ring sealing member 132 which engages the inside surface of the casing 39.

The rotor 62 is keyed in co-rotatable assembly with the shaft 51 by means of a key 133 and the ends of the shaft 51 are piloted in the porting plate 90 at a recess 134.

As shown in FIGURE 5, an end closure is provided on the cover 50 by means of a snap-on cap 140 which surrounds a shaft seal shown generally -at 141.

In order to limit the amount of adjustment, a stop pin is shown at 146 and is carried by the backing plate 91 and projects into an enlarged opening 147 formed in the pump ring 37.

In a typical operating arrangement, the burnernozzle is selected for operation at approximately 90 pounds per square inch and the flow regulator valve 36 is preset by the proper adjustment of the pressure adjustment screws 116 to afford a proper opening pressure. With the adjustability of the pump ring 37 available in accordance with the principles of the present invention, the output of the pump may be selectively varied to permit the operation of the circuit with the minimum displacement necessary to maintain a given pressure drop across any given orifice with no excess to be dumped.

Although minor modifications might be suggested by those versed in the art, it should be understood that we wish to embody within the scope of the patent warranted herein all such modifications as reasonably and properly come within the scope of our contribution to the art.

We claim as ou-r invention:

1. A pump comprising a casing establishing a reference axis,

a ring in said casing having a cylindrical bore Wall forming a pumping chamber,

a rotor rotatable in said pumping chamber on said reference axis,

means mounting said ring for pivotal movement in said casing to vary the relative displacement of said ring relative to said axis,

thereby to adjustably offset the -axes of said ring and said rotor,

means forming a peripheral axially extending recess in said motor having generally parallel side walls and a bottom wall,

la slipper in said recess having a radial outer sealing surface curved to engage the adjoining bore wall with surface contact and including first and second side walls disposed adjacent said side walls of said recesses,

said first and second side walls being shaped to permit said slipper to rock and to move inwardly and outwardly of said recess in following said bore wall,

said first side wall of said slipper engaging the adjoining side wall of said recess,

means forming a sealing pin interposed between said second side wall of said slipper and the other side wall of said recess,

and radially outer and inner porting means -in said casing respectively communicating with said pumping chamber radially outwardly of said sealing pin to form a first pumping circuit and with said recess radially inwardly of said sealing pin to form a second pumping circuit, said pumping circuits being connected in series with one another,

-a sealing pin recess in Ione of said side walls receiving said sealing pin for movement outward against the adjoining walls in sealed contact in response to centrifugal force to separate the pumping circuits,

and means forming diametrically opposed locking screw means offset from the pivot axis for locking said ring in adjustable locked position to vary the pumping output ofthe pumping circuits.

2. A furnace fuel system comprising an oil tank having cond-uit means forming a fuel inlet near the bottom of the tank,

a slipper-type pump comprising a housing formed with an inlet 'and an outlet,

a pivotally Imounted pump ring in said housing having an inner bore forming :a pumping chamber,

a rotor having at least one notch formed therein with radially extending side walls and being rotatable on an axis eccentrically offset in said pumping chamber,

a slipper received in said notch,

said slipper being of a width and thickness suliiciently less than the width and depth of the notch so that said slipper is free to move radially and rock angularly while following and engaging the inner bore of said pump ring to move fluid in said pumping chamber from the inlet to the outlet,

biasing means bottomed in said notch and engaging -7 said slipper to preload said slipper radially outwardly, s

said housing having means iforming a second inlet and la separate second outlet at the respective inlet and outlet sides of the pump and communicating with the innermost portions of said notch, said slipper being radially reciprocable in said notch and completing a stroke between said second inlet and said second outlet to develop a second pumping action, sealing means interposed between said slipper Aand said notch comprising means forming a recess,

and a pin in said recess outwardly thereof into sealing engagement with said slipper and the adjoining rotor wall in response to centrifugal force, thereby to separate inner and outer pumping circuits in the pump, means staging said outer and inner circuits in series ow relation, and means for adjustably locking said pump ring in selected positions with the axes of said ring and said rotor relatively offset, thereby to vary the pumping output of the pump in order to match the output of the pump to the burner nozzle.

3. A `furnace fuel system as defined in claim 2 and by-pass means including a by-pass regulator valve between said first stage pumping circuit and said fuel tank,

said outer circuit comprising a first stage pumping circuit and having a `greater capacity than said inner circuit which comprises a second stage pumping circuit, thereby to supercharge the second stage pumping circuit and the excess uid being returned to said oil tank.

4. A furnace fuel system as defined in claim 2 and a pressure regulating and shut-off valve for regulating the discharge from the pump, and a fixed orifice burner nozzle receiving the discharge from the pump. 5. In combination, a slipper pump comprising a housing having an inlet and an outlet, a pump ring in said housing having an inner bore forming a pumping chamber, a rotor in said ring having slippers movable radially and lrockable an'gularly in following the contour of said inner bore andr operating to pump liquid from the inlet to the outlet, va fixed orifice nozzle connected to. said outlet and receiving liquid from said pump, means forming a valve controlled by-pass between said outlet and said inlet, and means mounting said ring for adjustable pivotal movement in said housing, thereby to vary the displacement and thereby the pump output to maintain a selected pressure `drop across said orifice. 6. In combination, a slipper pump as defined in claim 5 and further characterized by said pump having dual pumping circuits including an outer pumping circuit in said ring forming a first pumping stage receiving uid from said inlet, and an inner pumping circuit inwardly of said slipper forming a second pumping stage receiving iiuid from said rst pumping stage and discharging to said outlet. 7. In combination, a slipper pump as defined in claim 6 and further characterized =by said outer pumping circuit having a capacity in excess of said inner pumping circuit, thereby to supercharge the second pumping stage.

References Cited UNITED STATES PATENTS 2,955,542 10/1960I Gaubatz 103-120 2,958,295 11/1960 Stern 103-120 2,142,275 l/ 1939 L ane 103-120 3,064,583 11/1962 Burt 103-120 3,067,693 12/ 1962 Lambeck 103-120 1,326,642 12/ 1919 Brown 15S-36.3 2,451,681 10/1948 Logan 15S-36.3 2,604,047 7/1952 Beaman et al. 103-5 2,606,499 8/ 1952 Witherell 103-11 2,606,603 8/ 1952 Witherell et al. 15S-36.3 X 2,797,643 7/ 1957 Sherman 103--161 2,938,469 5/1960 Lauck 103-136 X 3,038,412 6/1962 Clark 103--136 X 3,081,706 3/1963 Drutchas 103-136 X 3,272,138 9/1966 Connoy et al. 10.3--120 FREDERICK L. MATTESON, JR., Primary Examiner.

R. A. DUA, Assistant Examiner.