US3285180A

US3285180A - Oil burner pump

Info

Publication number: US3285180A
Application number: US332107A
Authority: US
Inventors: Robert A Mccallum
Original assignee: National Union Electric Corp
Current assignee: White Consolidated Industries Inc
Priority date: 1963-12-20
Filing date: 1963-12-20
Publication date: 1966-11-15
Anticipated expiration: 1983-11-15
Also published as: GB1088959A; SE310398B; NL6414838A; BE657418A; DE1528994A1; DK107964C; AT263981B

Description

Nov. 15, 1966 R. A. MCCALLUM 3,285,180

OIL BURNER PUMP Filed Dec. 20, 1963 5 Sheets-Sheet 1 Nov. 15, 1966 A. MCCALLUM 3,285,180

OIL BURNER PUMP Filed Dec. 20, 1963 5 Sheets-Sheet 2 16 6 INVENTOR.

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R. A. M CALLUM OIL BURNER PUMP Nov. 15, 1966 -Sheet 3 v 5 Sheets Filed Dec. 20, 1963 3 505m w, W a

United States Patent 3,285,180 OIL BURNER PUMP Robert A. McCallum, Normal, 11]., assignor to National Union Electric Corporation, Stamford, Conn., a corporation of Delaware Filed Dec. 20, 1963, Ser. No. 332,107 11 Claims. (Cl. 1037) This invention relates to pumps and more particularly relates to an improved pump for use with an oil burner.

Among the many considerations to be taken into account in the design and the construction of an oil burner pump are those of stability of the oil flow to the burner, efliciency and reliability of operation, and reduction in the overall size and cost of the unit. Many of the presently available oil burner pumps do not satisfy the foregoing considerations in that either they fail to maintain a stable oil flow under varying pressure conditions at the pump inlet or they fail to maintain reliability and efliciency when the size and cost of the unit are reduced.

Accordingly, it is the general object of the present invention to provide a novel and improved oil burner pump.

Another object is to provide a novel flow control system for an oil burner pump, which results in a more stable oil delivery.

A further object is to provide a novel flow control system of the foregoing character which automatically compensates for variations in the pressure of the oil at the inlet of the pump.

Still another object is to provide a novel pressure lubrication system for the shaft journal of an oil burner pump which eliminates the usual seals associated with the shaft.

A further object is to provide a novel and improved oil burner pump which is simple in construction, reliable in operation, and economical to manufacture.

These and other objects will become apparent from the following description and accompanying sheets of drawings, in which:

FIG. 1 is a longitudinal sectional view of an oil burner pump embodying the features of the present invention;

FIG. 1a is an enlarged fragmentary sectional View of a portion of the pump shown in FIG. 1;

FIGS. 2, 3, 4 and 5, are a series of vertical sectional views taken substantially along the lines 2-2, 33, 4-4 and 5-5, respectively, of FIG. 1;

FIG. 6 is an elevational view of the right end of the pump as viewed in FIG. 1;

FIG. 7 is an end elevational view of the left end of the pump as viewed in FIG. 1;

FIG. 8 is a fragmentary sectional view of the oil flow control structure of the pump and showing an alternate construction thereof;

FIG. 9 is a somewhat enlarged sectional view taken substantially along the line 99 of FIG. 8; and

FIG. 10 is a semi-diagrammatic view of the flow control and fluid displacing structure of the pump and showing the relationship thereof with respect to an associated oil tank.

Briefly described, the present invention contemplates an oil burner pump capable of supplying a stabilized flow of oil and air under pressure to an oil burner. Such unit, to be hereinafter described, employs a sliding vane type pump as the pressurizing means for supplying a frothy oil-air mixture to the burner. The burner, which forms no part of the present invention, includes means for separating the oil-air mixture into separate flows of oil and air which are supplied to the atomizing nozzle in the blast tube of the burner.

According to the present invention, novel flow control 3,285,186 Patented Nov. 15, 1966 means is provided for controlling the oil flow to the fluid displacing or pump means and hence the quantity and rate of oil flow being discharged by the pump. Such flow control means comprises a pressure responsive flow control valve and a metering orifice operably disposed in the oil inlet passages of the pump, between the oil inlet of the pump and pump means. The metering orifice is disposed downstream of the flow control valve.

The flow control valve comprises a shiftable plunger having a duct therein providing an oil flow path to the pump means. A diaphragm connected to one end of the plunger varies the position of the latter and the size of a port at one end of the duct, the port controlling the oil flow rate to the pump means. The diaphragm is mounted in a cavity in the pump and defines a pressure responsive chamber on each side of the diaphragm. One of the chambers is connected to the suction side of the pump means and the other chamber is at all times connected to the atmosphere. Spring means is provided for urging the plunger in a direction to close the valve, the force of the spring being overcome and the plunger shifted in a direction to open the valve when a predetermined negative pressure is obtained in the one chamber.

A novel pressure lubrication system for the journal of the pump shaft is also contemplated. Such lubrication system comprises a bore in the pump which intersects a portion of the shaft journal. The bore communicates with the discharge passage of the pump and serves as a reservoir for receiving and retaining a quantity of oil from the mixed flow of oil and air under pressure in the discharge passage. The oil in the reservoir is thus subject to discharge pressure which forces the oil along the shaft journal to effect lubrication of the journal. The aforementioned reservoir is defined around a tubular member or standpipe which serves as part of an air by-pass passage for returning excess amounts of air in the oil-air mixture to the suction side of the pump. Oil leakage from the shaft journal is also returned to the suction side of the pump means by a connection with the air inlet passage.

In FIGS. 1 and 2, an oil burner pump embodying the features of the present invention is illustrated. Such pump generally comprises a multiple section housing 11, including a right end section 12, a plate section 13, a central cylinder section 14, and a left end section 15. The various sections 1215 are detachably secured together, as by screws 16, to form the housing 11.

Secured to and extending somewhat outwardly from the right end section 12 is an oil filter or strainer 17. The strainer 17, in the present instance, comprises a generally cylindrical convoluted screen assembly 18 having its left end extending into an annular recess 19 in the outer end face of the end'section 12. The right end of the screen assembly 18 projects outwardly of the end section 12 and is enclosed and supported by a cup-shaped cover or cap 21. The cap 21 is held against an annular end face 22 on the end section 12 by .a screw 23 which extends through the end wall of the cap and into engagement with a yoke structure mounted on the end section 12, as will be described more fully later. An annular seal 24 is provided between the annular end face 22 and an annular flange 25 around the inner end of the cap 21. A spring 26 is interposed between the inner end wall of the cap 21 and the right end of the screen assembly 18 to urge the latter into engagement with the end section 12. An annular seal 27 is disposed between the inner end of the screen assembly 18 and the end section 12.

Fluid to be pumped, in this instance oil from a remote source such as a tank T (FIG. 10), may enter the right end section 12 through one of three bores, indicated at 31, 32, and 33, in FIG. 2. The end portion, indicated at 34, of a pipe which is connected to the tank T, is shown engaged with the bore 32 in FIGS. 1, 2, 6 and 7. The bores 31-33 thus comprise inlets for the oil. The unused bores, in this instance the

bores

31 and 33, are closed by plugs. 36.

After entering the housing section 12, the oil passes through the filter screen assembly 18 of the strainer 17 for passage through a novel flow control means which includes a control valve 100 and a metering orifice 150 located downstream of the control valve 100. The details of the construction and operation of the flow control means will be described more fully hereafter.

For effecting oil flow from the tank T to the pump and from the pumpto the oil burner (not shown), fluid displacing or pump means is provided. Such pump means, in the present instance, comprisesa sliding vane positive displacement type pump 30 (FIGS. 1, 4 and Thus, cylinder section 14 of the housing 11 is provided with a generally cylindrical opening or cavity having an inner peripheral wall 42. A cylindrical rotor 43 is disposed in the cavity and is mounted on the inner or right end of a drive shaft 44 (FIGS. 1 and 5) which is rotatably journaled in an axial bore 46 in the housing section 15. The axes of rotation of the shaft 44 and rotor 43 are eccentric vertically upwardly of the center of the cavity in the housing section 14 so that the periphery of the rotor 43, which is of a somewhat smaller diameter than that of the cavity, is substantially tangent to the wall 42 at a point adjacent the uppermost vertical extent of the cavity.

A plurality of longitudinally extending circumferentially spaced slots or grooves 47 are formed in the outer periphery of the rotor 43 for slidably receiving plate-like vanes 48. In the present instance, six circumferentially spaced slots 47 are provided, each of which is inclined in the direction of rotation of the rotor 43, which is indicated by the arrow in FIGS. 4 and 5. The vanes 48 thus comprise the fiuid displacing or pumping elements of the pump 30. Preferably, the outer radial edge, indicated at 52, of each vane 48 is convex or radiused outwardly so that each vane will at all times contact the inner wall 42 of the housing section 14 along a line of tangency as the vane rotates through a complete revolution. The curvature of the edges 52, which has been exaggerated somewhat in FIGS. 4 and 5, provides hydrodynamic lubrication between the engaging surfaces of the vanes 48 and the wall 42 which minimizes scraping or galling. When engaged with the wall 42, adjacent pairs of the vanes 48 define pumping chambers 53 therebetween, the volume of which changes as the rotor 43 rotates due to its eccentric mounting.

In order to provide a fiow path for oil from the inlets 31-33 to the pumping chambers 53 of the pump 30, passage means is provided. Such passage means includes a vertical bore 56 (FIG. 1) in the right housing section 12 communicating at its lower end with a chamber 57 defined by a recess or cavity 58 formed in the inner end wall of the housing section 12 and a flexible diaphragm 62 disposed between the engaging surfaces of the housing section 12 and the plate section 13. A space 59 between the opposite side of the diaphragm 62 and the plate section 13 is at all times in communication with the atmosphere by means of a port 60 and a connected radial bore 61 in the plate section 13.

The upper end of the bore 56 communicates with a flattened generally rectangular shaped chamber 63 (FIGS. 1, 1a and 2) formed by a depression or recess 64 in the upper surface of the housing section 12. A plate 66, preferably of thin gauge metal and extending transversely of the depression 64, defines the chamber 63. The plate 66 has a small opening therein defining the metering orifice 150. A shallow dish-shaped screen 67 is mounted immediately below the metering orifice 150 as a further precaution to the passage of foreign particles. The screen 67 is supported by a gasket 68 which engages the underside of the plate 66 and the upper surface of the 4 housing section 12 (FIG. 1a), and another gasket 69 is disposed between the upper surface of the plate 66 and a cover plate 70 which is secured to the housing section 12 by a plurality of screws 71.

The opening or metering orifice 150 is preferably formed by embossing or dimpling the material of the plate 66 to provide a hollow portion 72 projecting from the downstream side of the plate 66 and thereafter removing a sufiicient amount of material of the projecting portion 72 to break through the wall thereof and form the orifice opening 150. Preferably, the plate 66 is embossed or dimpled by a tool having a conically tapered point whose angle of taper is about 90 so that the inner side wall, indicated at 73, of the projecting portion 72 also has an included angle of taper of about 90. Because the inner side wall 73 thus formed is quite smooth, there is little chance that lint or other foreign particles will accumulate thereon.

The material of the projecting portion 72 is removed, preferably by grinding, to provide a fiat rear face 74 lying in a plane parallel to the downstream side of the plate 66. The intersection of the rear face 74 with the tapered inner side Wall 73 of the projecting portion 72 defines a sharp edge at the opening 150. This sharp edge minimizes the effects of visocity on the oil fiow through the orifice. The extent to which the embossed portion 72 is ground oif, of course, determines the size of the orifice.

The inner surface of the cover plate 70is recessed as at 75 to define a chamber 76 above the plate 66 and immediately downstream of the metering orifice 150. A transverse groove 77 (FIG. 2) in the under surface of the cover 70 connects the chamber 76 with a series of aligned

openings

78, 79 and 80 in the gasket 69, orifice plate 66, and gasket 68, respectively, and with the upper end of another vertical bore 82 (FIG. 2) in the housing section 12. The lower end of the bore 82 intersects an axially extending bore 83 which registers with coaxial bores 84 and 86 (FIG. 1) in the :plate section 13 and cylinder section 14, respectively. The inner or left end of the bore 86 intersects another vertical bore 87 in the cylinder section 14 (FIGS. 1 and 5) and has its lower end 88 opening into the cavity in the cylinder section 14. The opening 88 thus comprises aport for admitting oil to the pumping chambers 53 of the pump 30.

The upper end of the bore 87 may be enlarged and threaded as at 91 to provide a gauge port for measuring the suction pressure of the sliding vane pump 30 on the downstream side of the metering orifice 150. When not in use, the gauge port 91 may be closed by a plug 92.

Another gauge port defined by a vertical bore 93 (FIG. 2) is provided in the housing section 12 for measuring oil pressure immediately upstream of the metering orifice 150. Thus, the bore 93 communicates with the chamber 63 by means of a diagonal bore 94 in the housing section 12. The upper end of the bore 93 is threaded as at 96 to facilitate connection of a pressure gauge and to receive another plug 92, when the port is not in use.

As heretofore mentioned, the present oil burner pump is adapted to supplya mixture of oil and air under pressure to the oil burner. The structure which provides the air inlet and the various passages which connect the air inlet with sliding vane pump 30 will now be described.

As best seen in FIG. 1, the left end section 15 of the housing 11 includes an axially outwardly extending cylindrical boss portion 101 having a generally cylindrical axially inwardly extending recess 102 formed in the outer end face, indicated at 105, of the boss portion 101. A cupshaped mufiier cap 103 having a central opening 104 in its end wall is mounted on the outer end of the boss portion 101 in the manner illustrated in FIG. 1 with the shaft 44 extending through the opening 104. The diameter of the opening 104 is somewhat greater than that of the shaft 44 at its point of extension through the cap so that an annular space 106 is defined therebetween which comprises the air inlet for the flow of air entering the pump housing 11. The remote outer end, indicated at 107, of the shaft 44 is adapted to be connected to an electric motor or other power source for rotating the shaft 44 and rotor 43 of the pump 30.

After passing through the annular inlet 106, the air enters an annular mufiling chamber 108 defined around the shaft 44 and then flows axially inwardly into the cylindrical recess 102 and thence into the outer end of an axial bore 112 which communicates at its inner end with a transverse bore 113 (FIGS. 1 and 3). The outer end of the bore 113 is enlarged and threaded, as at 114, to receive the threaded end, indicated at 116, of a by-pass air adjusting screw 117, to be hereinafter described.

Upon entering the transverse bore 113, the air flows toward the outer end of the bore where it enters the upper end of a generally vertically extending bore 118, the lower end of which is closed as by another plug 92. The bore 118 is intersected intermediate its length by a pair of axial bores 119 and 120 (FIGS. 1 and 3) which extend inwardly from the inner end face of the housing section 15 to a point of intersection with the bore 118. The inner ends of the

bores

119 and 120 communicate with a pocket or recess 122 (FIGS. 1 and 4) formed in the left end face of the cylinder section 14. The inner ends of the

bores

119 and 120 thus comprise ports for admitting air to the pumping chambers 53 of the pump 30.

As will be apparent from FIGS. 1, 4 and 5, the oil inlet port 88 is separate and spaced circumferentially a substantial distance from the

air inlet ports

119 and 120. This spaced location of the

ports

88 and 119, 120 in the pump cavity is such that certain of the pump vanes 48 are always interposed between the respective oil and air inlet ports so that the latter may be at different pressures. For example, the oil inlet port 88 will normally be subjected to a high vacuum of about 27 inches of mercury when the pump is operating, whereas the vacuum at the

air inlet ports

119, 120 will normally be less than about 2 inches of mercury, thereby providing maximum operating efficiency for the pump.

Upon entering the pumping chambers 53, the air becomes intimately mixed with the oil entering the chambers 53 from the port 88 so that a frothy oil-air mixture is obtained. Such mixture is carried in the pumping chambers 53 toward another recess 123 (FIG. 4) in the left end face of the cylinder section 14, as viewed in FIG. 1, and located substantially opposite from the recess 122. The recess 123 is intersected by a short axial bore 124 which extends outwardly from the inner end face of the housing section 15. The inner end of the bore 124 thus comprises an exit port for the oil-air mixture from the pump 30. The outer end of the bore 124 intersects the inner end of another transverse bore 126 disposed above the shaft 44 and its bore 46. The outer end of the bore 126 is threaded, as at 127, for receiving a pipe (not shown) for conducting the oil-air mixture to the burner.

Because a greater quantity of air would be drawn into the air inlet 104 and supplied to the pumping chambers 53 than would usually be required, a by-pass arrangement is provided :for by-passing a portion of the air in the transverse bore 126 back to the inlet bores 119 and 120. To this end, air by-pass passage means is provided, the effective size of which is controlled by the air by-pass adjusting screw 117. The screw 117 thus includes an elongated stem portion 127 (FIG. 3), the inner end of which, indicated at 1-28, is tapered for cooperation with a smaller diameter bore 129 which extends coaxially inwardly from the bore 113. The inner end of the bore 129 intersects the lower end of a bore 130 which extends downwardly in the housing section 15 from the upper surface thereof. The upper portion, indicated at 131, of the bore 130, intersects the transverse bore 126. An elongated tubular member in the form of a standpipe 132 has its lower end seated in the bore 130 in sealed relation with the housing in the manner illustrated in FIG. 3 so that the upper end of the standpipe 132 is disposed above the transverse bore 126. With such an arrangement, the standpipe 132 will act as a separating means in that substantially only excess air in the oil-air mixture flowing outwardly in the bore 126 toward the outlet 127 will flow into the open upper end, indicated at 133, of the standpipe 132 to be conducted by the

air passages

130, 129, 113 and 118, back to the

air inlet ports

119 and 120. Adjustment of the screw 117 in its threaded bore 114 controls the effective size of the bore 129 and consequently the amount of air by-passed.

As heretofore mentioned, the present pump includes a novel pressure lubrication system for the journal of the shaft 44. To this end, the enlarged portion 131 of the bore intersects the bore 46 in which the shaft 44 is mounted and provides an annular chamber or reservoir 134 around the lower portion of the standpipe 132 which receives a protruding or exposed portion of the journal of the shaft 44. The upper end of the enlarged bore 131 may be threaded as at 135 to receive a plug, such as the plug 36.

The annular chamber or reservoir 134 is in communication with the transverse bore 126 through which the frothy oil-air mixture is flowing and serves to entrap and retain a portion of the oil from the mixture which collects in the lower portion of the chamber. The exposed journal of the pump shaft 44 is thus in contact with oil contained in the reservoir 134, and because the latter is subject to pressure from the discharge side of the pump, such oil is forced inwardly along the shaft journal to effect lubrication.

It will be noted that no seals are provided along the bearing bore 46 of the shaft 44. Thus, a portion of the lubricating oil flow from the lubrication reservoir 134 flows along the shaft journal toward the cylinder section 14 and ultimately finds its way into the pumping chambers 53 to be discharged through the port 124. The other portion of the lubricating oil flow works its Way toward the outer end of the housing section 15 at which point it gravitates across the outer end face 105 of the boss portion 101 toward the cylindrical recess 102. Such oil is caused to flow axially inwardly in the recess 102 toward the bore 112 and connected air inlet passages due to the air flow from the inlet 106 entering these passages.

Thus, the aforementioned shaft journal lubrication system not only eliminates the needs for seal-s at the ends of the shaft bearing bore, but also provides for the return of the lubricating oil flow back to the pumping chambers of the device.

In some instances, it may be desirable to minimize the size of the air inlet 106. To permit such minimization, it would be necessary to provide another or supplemental air inlet passage communicating with the pumping chambers 53 for supplying additional air thereto. A suit-able air filter and muflier could be provided at the inlet end of such other passage. Because an air flow rate must be maintained through the annular recess 102 and bore 112 sufficient to draw lubricating oil back into the pumping chambers should not be so small nor supplemental air passage be so large that the air flow through the recess 102 and bore 112 would fall below the aforementioned minimum.

As heretofore mentioned, the present oil burner pump includes flow control means for controlling oil flow to the pumping chambers 53 of the pump 30, such flow control means being effective to compensate for variations in the oil pressure at the inlets 31-33 resulting from changes in the oil level in the tank T (FIG. 10).

Referring again to FIGS. 1 and 2, the flow control valve 100, in this instance, comprises a tubular plunger 136 slidably mounted in a tubular bushing 137 which is pressed into an axial bore 139 formed in a central axially outwardly extending boss 140 on the outer side of the housing section 12. The bushing 137 has an annular radially outwardly extending flange 141 at one end '53, the size of the air inlet 106 the effective size of the thereof, which is adapted to engage the flat end face of the boss 140. The plunger 136 has a length such that its inner end at all times extends into the chamber 57 throughout the range of movements of the plunger 136. The interior of the tubular plunger thus comprises a duct for the flow of oil from the interior of the strainer 17 to the chamber 57. A dished or shallow cup-shaped member 142 is secured to the inner end of the plunger 136 to provide an enlarged area of contact for engaging the diaphragm 62.

A cup-shaped cap member 143 having an radially outwardly extending flange 144 around its open end is pressed onto or otherwise secured to the outer end of the plunger 136. Means in the form of a collar, in this instance an O-ring 146, is mounted on the plunger 136 for cooperation with the adjacent end faces of the bushing 137 and cap member 43 to vary the flow through the duct in the plunger 136. The O-ring 146 normally engages the cap 143 in the manner illustrated in FIG. 1 and, together with the adjacent end face of the bushing 137, defines an annular variable area space or port 147 which Iar6ies in size as a function of the position of the plunger In order to permit oil to enter the upstream end of the duct in the plunger 136, the latter is provided with at least one, and in the present instance, a pair of axially spaced diametrical bores 148 which are arranged closely adjacent and at each side of the usual position of the O- ring 146. Another diametrical bore 149 is provided in the plunger 136 toward its inner end to provide the aforementioned continuous communication of the plunger duct with the chamber 57. Thus, when the plunger 136 shifts outwardly or toward the right, as viewed in FIG. 1, oil may flow from the interior of the strainer through the annular port 147 and through either or both of the bores 148, depending upon the position of the O-ring 146 with respect to the plunger 136. Upon entering the duct in the plunger 136, oil flows inwardly and then outwardly through the bore 149 into the chamber 57. Thus, the axial position of the plunger 136 determines the sin of the annular port 147 and consequently the flow rate through the passage or duct in the plunger 136.

Means in the form of a spring 151 is provided for normally urging the plunger 136 inwardly or in a direction to reduce the size of the angular port 147. The spring 151 is mounted between the legs, indicated at 152, of a U-shaped yoke 153 so that the inner end of the spring 151 is piloted on the cap member 143 and in engagement with the flange 144, the outer end of the spring engaging the connecting or web portion, indicated at 154, of the yoke. The yoke 153 may be secured to the housing section 12 by screws 156 (FIG. 2) which extend through openings in flanges 157 on the inner ends of the legs 152 and which are threaded into the fiat end face of the boss 140. The right or outer end of the spring 151 is piloted by a guide or spud 158 mounted in the web portion 154 of the yoke 153. The spud 158 includes a tubular axially outwardly extending portion 159 which is internally threaded to receive the screw 23.

Referring now to FIG. in conjunction with FIG. 1, the operation of the control valve 100 will be described. In FIG. 10 the portions of the pump which are necessary for an understanding of the operation of the control valve 100 are illustrated semi-diagrammatically in order to simplify the description. Thus, as will be apparent from the figure, a quantity of oil to be pumped is shown contained in the reservoir or tank T. The level of the oil when the tank T is full is indicated at l; and at 1 when the tank T is nearly empty. A conduit or pipe 163 connects the tank T with the inlet 32 which communicates with the strainer 17 (not shown in FIG. 10), and thence withthe control valve 100. A shutoff valve 164 may be provided in the conduit 163.

Depending upon the position of the tank T with respect to the valve 100, a positive or negative pressure will be imposed upon the valve 100. Such pressure acts on the cap member 143, in addition to the force of the spring 151, and tends to close or open the valve 100. Assuming a tank arrangement such as shown in FIG. 10, it will be apparent that the control valve will be subject to a postive pressure when the tank is full, such pressure becoming less positive as the oil level falls from the level 1 to the level 1 where a slight negative pressure may occur. The spring 151 has a rating such as will maintain the valve 100 closed when the pump 30 is inoperative or when the valve is subject to negative pressures as when the level of the oil in the tank T is below the height of the valve. Because the eifective area of the cap 143 is relatively small in comparison to the effective area of the diaphragm 62, positive or negative pressures in the interior of the strainer 17 have a negligible efiect on the position of the plunger 136.

When an associated thermostat or temperature sensitive device energizes the motor to which the pump shaft 44 is connected, the rotor 43 will be rotated and suction will be developed at the oil inlet port 88 and the pressure in the chamber 57 will drop. The sliding vane pump 30 produces a vacuum of approximately 27 inches of mercury or 13 psi. negative which is present in the chamber 76. The size of the opening of the metering orifice 150, the area of the diaphragm 62 at one side of the chamber 57, and the rating of the spring 151 are chosen so that a vacuum of approximately 9 or 10 inches of mercury or about 4 /2 p.s.i. negative is obtained in the

chambers

57 and 63. Thus, a substantially constant pressure drop of approximately 17 to 18 inches of mercury is maintained across the metering orifice 150. I have found that such a drop is obtained when the exposed area of the diphragm 62 in the chamber 57 is approximately two' square inches and the force exerted by the spring 151 on the plunger 136 is about 9 pounds.

When the pressure in the chamber 57 drops to a value such that atmospheric pressure acting on the diaphragm 62 and the plunger 136 is sufficient to overcome the force of the spring 151, the plunger 136 will shift toward the right to open the valve 100. The plunger 136 will continue to shift toward the right to increase the size of the annular port 147 untilan oil flow rate is obtained through the plunger duct equal to that through the metering orifice 150. A stable flow condition will thus be obtained. However, as the level of the oil in the tank T drops, say from the level to the level l the oil inlet pressure will also fall resulting in a decrease in flow rate through the port 147 and the plunger duct and a decrease in fluid pressure in the chamber 57. Consequently, the plunger 136 will shift farther toward the right or in a direction to provide a larger port area 147 and a greater oil flow through the plunger duct thereby maintaining a substantially constant pressure drop across the orifice 150.

Because of the fact that atmospheric pressure is at all times present in the chamber 59 on the opposite side of the diaphragm 62, any failure of the latter will result in movement of the plunger toward the left and a closing of the valve. Such failure or rupture of the diaphragm 62 will be manifest by oil dripping from the lower end of the passage 61.

It will thus be apparent that the valve 100 not only functions as a shutolf valve when the pump is inoperative, but also as an oil control valve when the pump is operating in that it serves to maintain a substantially uniform pressure drop across the orifice 150 and consequently a substantially constant flow rate to the inlet 88 of the sliding vane pump, regardless of changes in the inlet oil pressure in the strainer 17.

As an incident to controlling oil flow to the pump 30, the valve 100 also exerts a control efiect on the above mentioned shaft lubrication system, particularly the flow of lubricating oil along the shaft journal. Thus, when the valve 100 is functioning to maintain a substantially constant oil How to the pump 30 it also serves to maintain a substantially constant flow of lubricating oil along the shaft journal.

In FIGS. 8 and 9 an alternate construction of the control valve is illustrated and indicated generally at 170, the latter comprising a second embodiment of the invention. Like reference numerals have been used to indicate parts identical with those of the control valve 100.

The valve 170 is mounted in the right end section 12 of the housing 11 in the same manner as the valve 100 for controlling oil flow to the chamber 57. The valve 170 thus includes an elongated plunger 171 shiftably mounted in a bushing 172 pressed into an axial bore 173 in the housing section 12. A shallow cup-shaped member, generally in the form of a disk 174, is secured as by a screw 176 to the left or inner end of the plunger 171 for engaging the diaphragm 62. A cup-shaped cap member 177 is pressed onto or otherwise secured to the opposite end of the plunger 171 and an O-ring 146 is mounted on the plunger 171 between the bushing 172 and the cap 177 in the manner illustrated in FIG. 8. The inner end of the spring 152 bears against the cap member 177 in the same manner as in the previous embodiment.

The valve 170 differs from the valve 100 as to the construction of the duct which connects the annular space or port 147, defined between the O-ring 146 and the adjacent end face of the bushing 172, with the chamber 57. Thus, the plunger 171 is provided with a plurality of axially extending circumferentially spaced grooves or serrations 178 (FIG. 9) in its outer periphery, the serrations 178 extending for the full length of the plunger and thus together defining a duct through which oil may flow. The combined cross-sectional area of the serrations 178 is sufliciently great as will prevent any appreciable restriction of the flow at this point.

Control of the area of the duct in the plunger 171 is achieved in the same manner as in the valve 100, that is by the position of the O-ring 146 with respect to the adjacent end face of the bushing 172 which controls the size of the annular space or port 147.

Variations and modifications of the structure herein disclosed may be effected without departing from the scope of the invention as set forth in the appended claims.

I claim:

1. In a fluid pump adapted for use with an oil burner or the like, the combination of a housing having an inlet and an outlet and a cavity therein, pump means in said cavity, inlet passage means connecting said inlet with said cavity, outlet passage means connecting said cavity with said outlet, and flow control means including valve means responsive to the difference between suction pressure in said inlet passage means and atmospheric pressure for varying the position of said valve means, said flow control means also including spring means acting on said valve means in opposition to the force resulting from the difference between suction and atmospheric pressure, and a plate extending transversely of said inlet passage means and having an opening therein having a side wall tapering inwardly toward the downstream side of said plate, said opening defining a metering orifice cooperating with said valve means to control fluid flow to said pump means.

2. The structure of claim 1 further characterized in that said side wall is conically tapered and has an included angle of taper of about 90.

3. The structure of claim 1 further characterized in that said plate is embossed to provide a hollow portion projecting from the downstream side of said plate, and a portion of the material of said projecting portion is removed to provide said opening, said material being removed so as to define a flat face on said projecting portion providing a sharp edge at said opening, whereby the effects of viscosity on the fluid flow through said opening are minimized.

4. In an oil burner pump comprising pump means having an air inlet, an oil inlet, and an outlet for an airoil mixture, the improvement comprising oil passage means for supplying oil from a source to said oil inlet, metering orifice means of fixed size in said oil passage means upstream from said oil inlet, a control valve in said oil passage means upstream from said metering orifice means, spring means normally urging said valve to closed position, diaphragm means connected to said valve for opening and varying the position of the same, said oil passage means including means subjecting one side of said diaphragm means to suction pressure from said pump means between said metering orifice means and said valve, and means subjecting the opposite side of said diaphragm means to atmospheric pressure, whereby said valve is movable in response to changes in the pressure difference on opposite sides of said diaphragm means to vary the flow through said oil passage means, said valve thereby coacting with said metering orifice means to control flow to said pump means.

5. In a fluid pump adapted for use with an oil burner or the like, a housing having an inlet, an outlet and a cavity therein, said housing also having an end wall and a bore therethrough, inlet passage means connecting said inlet with said cavity, outlet passage means connecting said cavity with said outlet, pump means in said cavity providing suction at said inlet and discharge at said outlet, flow control means for controlling fluid flow through said inlet passage means comprising a shiftable plunger slidably mounted in said bore in said end wall, said plunger having a duct therein comprising a portion of said inlet passage means, one end of said duct opening on the outer side of said end Wall and the other end of said duct opening on the inner side of said end wall, a collar mounted on said plunger adjacent said one end of said duct, said collar coacting with the outer side of said end wall to control the flow through said duct, and diaphragm means in said housing connected to said other end of said plunger for shifting the latter in said bore, said diaphragm means and said end wall defining a chamber communicating with the suction side of said pump means and comprising another portion of said inlet passage means, the opposite side of said diaphragm means and said housing defining another chamber exposed to atmospheric pressure, whereby movements of said plunger in response to changes in the pressure difference between said chambers causes variations in the flow through said duct to thereby control fluid flow through said inlet passage means.

6. In a fluid pump adapted for use with an oil burner or the like, a housing having a liquid fuel inlet, an air inlet, a mixed fluid outlet, and a cavity therein, liquid fuel passage means connecting said liquid fuel inlet with said cavity, air inlet passage means connecting said air inlet with said cavity, mixed fluid passage means connecting said cavity With said mixed fluid outlet, said housing also having a bearing bore therein disposed below said mixed fluid passage means, a rotatable shaft having a journal mounted in said bearing bore, rotary pump means mounted on said shaft and operably disposed in said pump cavity, said rotary pump means providing suction at said liquid fuel and air inlets and discharge at said mixed fluid outlet upon rotation of said shaft, air and liquid fuel separating means communicating with said mixing fluid passage means, and means associated with said separating means defining a lubrication reservoir in said housing communicating with said shaft journal and said mixed fluid passage means, said lubrication reservoir receiving liquid fuel from mixed fluid passage means and being subject to discharge pressure from said pumps means, whereby liquid fuel in said reservoir is forced along said shaft journal to effect lubrication thereof.

7. The structure of claim 6 further characterized in that said bearing bore is free of seals, thereby permitting liquid fuel to flow along said shaft journal and outwardly of said bearing bore.

8. The structure of claim 6 further characterized in that said mixed fluid passage means is disposed above said bearing bore and said housing includes a downwardly extending bore intersecting said mixed fluid passage means and said bearing bore and defining said lubrication reservoir, at least a portion of said shaft journal at all times being in direct contact with liquid fuel in said reservoir.

9. The structure of claim 6 further characterized in that said air and liquid fuel separating means includes a downwardly extending bore in said housing intersecting said mixed fluid passages means and said bearing bore, a tubular member is mounted in said downwardly extending bore with the lower end of said tubular member engaging said housing in sealed relation, and said lubrication reservoir is defined around said tubular member.

10. In combination in a fluid pump adapted for use with an oil burner or the like, a housing having a liquid inlet, an air inlet, a mixed fluid outlet, and a cavity therein, said housing also having a bearing bore therein, a rotatable shaft having a journal mounted in said hearing bore, air inlet passages means connecting said air inlet with said cavity, liquid inlet passage means connecting said liquid inlet with said cavity, and mixed fluid passage means connecting said cavity with said mixed fluid outlet, rotary pump means carried by said shaft and disposed in said cavity, said pump means providing suction at said inlets and discharge at said outlet upon rotation of said shaft, flow control means for controlling liqiud flow to said pump means comprising valve means operably disposed in said liquid inlet passage means, and means responsive to the difference between suction pressure in said liquid inlet passage means and. atmos pheric pressure for varying the position of said valve means to control liquid flow to said pump means, and means in said housing defining a lubrication reservoir communicating with said shaft journal and said mixed fluid passage means, said lubrication reservoir receiving liquid from said mixed fluid passage means and being subject to discharge pressure from said pump means whereby liquid in said reservoir is caused to flow along said shaft journal to lubricate the same, said valve means in said liquid inlet passage means also exerting a control efrect on the flow of lubricating liquid along said shaft journal as an incident to controlling liquid flow to said pump means.

11. The structure of claim 10, further characterized in that said flow control means includes a metering orifice in said liquid inlet passage means between said valve means and said pump means, said metering orifice coacting with said valve means to control liquid flow to said pump means.

References Cited by the Examiner UNITED STATES PATENTS 1,757,514 5/1930 Coulombe 103-7 1,791,363 2/ 1931 Lewis 230-223 2,044,867 6/ 1936 Woodard 103-40 2,468,118 5/1949 Schulty 103-7 2,779,533 1/1957 Ziocks 230-207 2,829,601 5/ 1958 Weinfurt et al. 103-76 2,918,009 12/ 1959' Crevoisier 103-7 2,992,769 7/1961 Manzanera 230-207 3,016,184 1/1962 Hart 230-207 3,057,546 10/1962 Power 230-207 3,088,660 5/ 1963 Voggenthaler 230-207 3,089,430 5/1963 Shafer et al. 230-223 3,117,525 1/1964 Rosaen 103-40 MARK NEWMAN, Primary Examiner.

DONLEY I. STOCKING, JULIUS E. WEST, Examiners.

W. L. FREEH, Assistant Examiner.

Claims

1. IN A FLUID PUMP ADAPTED FOR USE WITH AN OIL BURNER OR THE LIKE, THE COMBINATION OF A HOUSING HAVING AN INLET AND AN OUTLET AND A CAVITY THEREIN, PUMP MEANS IN SAID CAVITY, INLET PASSAGE MEANS CONNECTING SAID INLET WITH SAID CAVITY, OUTLET PASSAGE MEANS CONNECTING SAID CAVITY WITH SAID OUTLET, AND FLOW CONTROL MEANS INCLUDING VALVE MEANS RESPONSIVE TO THE DIFFERENCE BETWEEN SUCTION PRESSURE IN SAID INLET PASSAGE MEANS AND ATMOSPHERIC PRESSURE FOR VARYING THE POSITION TO THE FORCE RESULTING FLOW CONTROL MEANS ALSO INCLUDING SPRING MEANS ACTING ON SAID VALVE MEANS IN OPPOSITION TO THE FORCE RESULTING FROM THE DIFFERENCE BETWEEN SUCTION AND ATMOSPHERIC PRESSURE, AND A PLATE EXTENDING TRANSVERSELY OF SAID INLET PASSAGE MEANS AND HAVING AN OPENING THEREIN HAVING A SIDE WALL TAPERING INWARDLY TOWARD THE DOWNSTREAM SIDE OF SAID PLATE, SAID OPENING DEFINING A METERING ORIFICE COOPERATING WITH SAID VALVE MEANS TO CONTROL FLUID FLOW TO SAID PUMP MEANS.