US3850548A

US3850548A - Oil burner pump

Info

Publication number: US3850548A
Application number: US00331611A
Authority: US
Inventors: W Delancey
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-02-12
Filing date: 1973-02-12
Publication date: 1974-11-26
Anticipated expiration: 1991-11-26

Abstract

In a variable capacity pump with an inlet port and a discharge outlet adapted for connection to a nozzle, a cylinder within the pump body having a casing and a pump stator slidably mounted in the cylinder and receiving a vaned rotor for receiving fluid from said inlet and discharging to said outlet; the improvement which includes a delivery chamber receiving said pumped fluid with a cut off valve opening. Said opening includes a valve seat with a soft valve in one end of the movable stator normally engaging said seat. A spring retainer is normally spaced outwardly of one end of the stator and a weak air release spring is interposed between said retainer and said stator. A discharge pressure spring is interposed between the pump body and said retainer, normally holding the retainer during initial movement of the stator towards and into engagement with the retainer so that initial low pressure air delivered to said chamber lifts the soft valve from said seat for delivery to said nozzle. Solid liquid subsequently pumped to said chamber of progressively increasing pressure causes the stator to move further radially outward against the action of said discharge pressure spring further opening said valve to reach an equilibrium of volume of pumped liquid delivered to said nozzle. The improved pump includes opposed pairs of intake and outlet grooves upon opposite sides of the stator registerable with corresponding pairs of intake and discharge ports extending through the inner and outer walls of the pump cylinder together with opposed bosses upon opposite sides of said stator normally closing one of each pair of intake and discharge ports whereby, the stator is reversible face to face, depending upon the direction of rotation of the rotor. An improved drive shaft seal is incorporated into the pump body which includes a stationary seal element on the body and a rotative seal element engageable therewith and connected with said drive shaft.

Description

United States Patent [191 DeLancey 1 3,850,548 [451 Nov. 26, 1974 1 1 OIL BURNER PUMP [76] Inventor: Warren H. DeLancey, 1580 Prospect Rd., Apt. 1-1-4, Elyria, Ohio 44035 [22] Filed: Feb. 12, 1973 [21] Appl. No.: 331,611

[52] U.S. C1 417/220, 418/31, 417/310 [51] Int. Cl. F04b 49/00 [58] Field of Search 417/310, 213, 219, 220, 417/315, 442, 259; 418/15, 31, 39, 97, 100, 26, 24, 25, 27

[56] References Cited UNITED STATES PATENTS 2,291,424 7/1942 Wichorek 417/239 2,451,279 10/1948 DeLancey 417/213 2,518,578 8/1950 Tomlinson 418/27 2,678,607 5/1954 Hufferd et a1. 417/220 2,746,391 5/1956 Jaworowski et a1. 417/239 3,187,676 6/1965 Hartmann 418/31 3,379,006 4/1968 Eickman 417/220 Primary Examiner-William L. Freeh Attorney, Agent, or Firm-Cul1en, Settle, Sloman & Cantor [57] ABSTRACT In a variable capacity pump with an inlet port and a discharge outlet adapted for connection to a nozzle, a cylinder within the pump body having a casing and a pump stator slidably mounted in the cylinder and receiving a vaned rotor for receiving fluid from said inlet and discharging to said outlet; the improvement which includes a delivery chamber receiving said pumped fluid with a cut off valve opening. Said opening includes a valve seat with a soft valve in one end of the movable stator normally engaging said seat.

A spring retainer is normally spaced outwardly of one end of the stator and a weak air release spring is interposed between said retainer and said stator. A discharge pressure spring is interposed between the pump body and said retainer, normally holding the retainer during initial movement of the stator towards and into engagement with the retainer so that initial low pressure air delivered to said chamber lifts the soft valve from said seat for delivery to said nozzle. Solid liquid subsequently pumped to said chamber of progressively increasing pressure causes the stator to move further radially outward against the action of said discharge pressure spring further opening said valve to reach an equilibrium of volume of pumped liquid delivered to said nozzle, The improved pump includes opposed pairs of intake. and outlet grooves upon opposite sides of the stator registerable with corresponding pairs of intake and discharge ports extending through the inner and outer walls of the pump cylinder together with opposed bosses upon opposite sides of said stator normally closing one of each pair of intake and discharge ports whereby, the stator is reversible face to face, depending upon the direction of rotation of the rotor. An improved drive shaft seal is incorporated into the pump body which includes a stationary seal element on the body and a rotative seal element engageable therewith and connected with said drive shaft.

15 Claims, 8 Drawing Figures on BURNER PUMP BACKGROUND OF THE INVENTION The present invention is an improvement over my earlier issued US. Pat. No. 2,451,279 issued Oct. 12, 1948 entitled VARIABLE CAPACITY VANE PUMP FOR OIL BURNERS.

Heretofore, in variable capacity pumps, particularly adapted for oil burners, though not limited thereto, and as shown in US. Pat. No. 2,451,279, fluid enters and leaves the pump through ports in the end cover at right angles to its movement in the pump. This construction is universally employed in oil burner pumps to this day. With the adventof the high speed oil burners, such porting requires the fluid at inlet and outlet to accelerate and decelerate twice during its passage through the pump to substantiallyhigh velocities, which in itself, is a measurable increase of torque requirement.

In present oil burner constructions, the direction of flow through the pump'has not been standardized and the pump manufacturers offer pumps which can be driven in either direction. This has, heretofore, required major changes of pump porting. and internal conduit arrangement.

Heretofore, it has been common practice in face seal constructions to have a spring which forces one face having a limited movement against another face of the seal which is fixed. One of these faces is stationary and the other revolves with the shaft to be sealed. The spring employed has a thrust in the oppositedirection which must be stablized between a moving and a stationary surface. It has been customary to make these surfaces as large as the seal itself which has roughly doubled the rubbing friction of the seal.

It has been common and universal construction in the past on oil burner pumps used on the popular so-called high pressure atomizing burners to prevent flow of fluid being pumped going to the nozzle 'until a predetermined and safe atomizing pressure was reached. Likewise, during operation when the pump has stopped at the end of an operating cycle, this valve to the nozzle would promptly close. These pressures were such that they could only be generated by the pump if it were pumping liquid. There was, however, occasions when there was not sufficient liquid in the pump, such as at original start or to start after a tank supply has been exhausted, and the burner has ceased operation for want of oil. It was, therefore, necessary to prime the burner through a priming plug which was often a costly service operation.

BRIEF DESCRIPTION OF THE INVENTION I It is an object of the present invention to provide an improved method of porting which increases pump efficiency. This is accomplished by providing an improved pump slide or movable stator which is thinned on both sides at inlet and outlet ports to provide access for fluid to the varying spaces provided by the blades and rotor. Thus, fluid can enter substantially in the direction of the flow through the pump and is discharged in the same direction. There is none of the violent accelera' tion and deceleration as formally, with consequent saving of power required to drive the unit.

It is another object to provide in the present variable capacity pump a symmetrically constructed movable stator with passages for inlet and discharge upon its opposite sides so that for a desired reversal in the direction of drive, the only change required is to reverse the positioning of the stator slide fromface to face. There is provided inlet and outlet passages or ports on both sides of the pump stator slide together with port covers upon opposite sides of the stator in the form of bosses over. The proper inlets in the rear pump plate and outlets on the front plate are covered or uncovered as required. No other changes are needed, no special parts or machining changes are required.

- It is another object to provide an improvedmeans of taking up the spring thrust from the face seals for the drive shaft to greatly reduce torque requirement on such seals. For this purpose, there is provided a stationary seal in the pump body which receives the drive shaft and spring biased thereagainst is a nose piece with an annular flanged surface for sealing engagement therewith and which is movable on the said shaft and wherein, a seal drive is mounted upon the shaft in en gagement with the nose piece and, the spring forces between the seal drive and the nose piece maintain the nose piece in contact withthe seal to limited areas, but at the same time, the thrust from the spring may be transmitted to the drive shaft with means to provide for limited friction and thrust take up and wherein, seal drive and the nose piece may be drivingly connected.

It is another object of the present invention to provide within the discharge chamber a valve seat assembly which permits the discharge of initial air through the conduit to the nozzle at constant low pressures while still requiring normal higher adjustable operating pressures when pumping solid oil. This improvement is also applicable to the fixed displacement type of pump where a separate piston type of bypass valve control is employed. It is the purpose of the present invention to provide a means for discharging the air atrelatively low pressure out of the nozzle conduit into the tire box while at the same time, providing that when oil reaches the pump, the normal adjustable pressure will be generated.

These and other objects will be seen from the following specification and claims in conjunction with the appended drawings:

THE DRAWINGS FIG. 5 is a side elevational view of the front pump plate shown in FIG. 1;

FIG. 6 is an end elevational view of the interior of the pump body with the cylinder removed taken in the direction of arrows 6-6 of FIG. 1, on a reduced scale;

FIG. 7 is a right end elevational view of the pump shown in FIG. 1, on a reduced scale;

FIG. 8 is a schematic vertical section of a constant displacement type of pump showing a modified nozzle shut off valve in conjunction with an air control spring and a main pressure control and bypass spring with a valve controlling piston in the discharge chamber.

DETAILED DESCRIPTION OF THE INVENTION It will be understood that the above drawings illustrate merely a preferred embodiment of the invention and that other embodiments are contemplated within the scope of the claims hereafter set forth.

Referring to the drawings, a variable capacity pump 11 is shown, FIGS. 1, 2 and 7, including body 13 with removable cover 15.

Fluid inlets 17 and 19 are formed as a part of the body, FIG. 2, and may be selectively used. One such inlet is closed by the plug 21, providing communication to chamber 23 upon the interior of said cover.

A cylinder is provided within the pump body which includes the upright rear pump plate 25 having an annular exterior groove 27 formed therein, FIG. 1, adjacent the hardened metal shroud 29 secured to the rear pump plate and extending outwardly thereof.

The cylinder has an upright front pump plate 31 which includes the lateral hub 33 having a bore 35 adapted to receive a power operated pump shaft 37 which is connected to and drives the rotor 39, FIGS. 1 and 2.

Thrust cone 41 is formed upon the inner end of shaft 37 and is adapted for cooperative end thrust registry with the shroud 29.-

The rotor has nested within its opposite sides suitable rings 43 for mechanically keeping the pump vanes 45 in contact with the bore of stator slide 51. A series of and upon the opposite side, the delivery chamber 49.

Said stator is nested within a pump outer casing 52 and includes at opposite ends the extensions or guide plates 53 movable within corresponding radial slots 55 fonned in the pump outer casing and suitably sealed with respect thereto at 57.

One of the extensions or guide plates 53 forms with slot 55 a delivery chamber 59 adapted for connection with a discharge outlet as at 139, FIG. 2, for connection with a nozzle such as employed in an oil burner.

The chamber 59 includes a cut off valve opening which consists of the nozzle cut off valve seat 61 and a soft valve 63 mounted upon the slide extension 53 of the stator 51 and normally in registry with said seat for closing off flow to the discharge passage 139.

Upon the opposite side of the body 13 there is provided the radial boss 65 within which is positioned spring'retainer 69 which normally bears upon the rear and front pump plates 25 and 31 with air release spring 67 interposed between the stator slide 51 and said spring retainer.

The air release spring is a relatively weak spring adapted to yield at pressures in the range of between and 35 pounds per square inch. A much stronger discharge pressure spring 71 is nested within the boss 65 and interposed between the spring retainer and the body adapted to normally resist relative outward movement of said spring retainer.

An adjustable screw nut 73 bears against the outer end of the discharge pressure spring 71 and threadedly receives adjusting screw 75 anchored with respect to seal plates 77 with screw seal 79 interposed therebetween.

Referring to FIGS. 1 and 7, the pump body includes an elongated axial boss which tenninates in mounting flange 81. Seal cover 83 is apertured to receive the pump shaft 37 and is secured to the outer face of flange 81 and mounts an apertured disc-like seal 87 seated against the body with seal 87 gasket imposed.

A longitudinally adjustable and rotatable nose piece 89 has an axially extending annular seal flange 91 adapted for sealing has a laterally extending seal flange 91 adapted for sealing registry throughout 360 with the seal 87 with a suitable O ring 93 interposed between said nose piece and shaft. Said nose piece is of carbon or other suitable material.

Seal drive 95 is mounted upon shaft 37 and secured thereto for rotation therewith by the transverse pin 101. Seal spring 103 is interposed in compression between said seal drive and nose piece 89 normally urging said nosepiece into cooperative sealing registry with seal 87.

Suitable drive means are employed between the seal drive and the nose piece in the form of splines 99 between the corresponding registering ends of the seal drive and nose piece so that the nose piece rotates with the drive shaft.

Since the compression spring 103 is biased against the seal drive due to the pin 101,'said spring tends to urge the pump shaft 37 axially inward and its end thrust is taken up with a minimum of friction due to the conical end 41 in registry with shroud 29.

Within the rear pump plate 25 in registry with its exterior annular groove 27 are a pair of spaced

axial ports

105 and 107 which communicate with the fluid in chamber 23 upon the outside of the cylinder for delivery into pumping chamber 47,49.

Diammetrically opposed bosses 109 and 111 FIG. 3 project from opposite sides of stator 51 so that in one position of said stator between saidend plates the boss 109 covers and blocks one of the

ports

105 and 107. Central portions of the stator upon its opposite sides are thinned out to define upon the opposite faces thereof, slots or inlet passages 1 13 which communicate with the chamber 115 within the pump casing and likewise communicate with one of the

ports

105 and 107 in the rear pump plate.

Upon the opposite side of the stator which is also thinned out, there are provided a pair of slots or outlet passages 117, one of which is adapted for communication with one of the outlet ports 119 and 121 formed in the front pump plate 31.

The latter outlet ports 119 and 121 communicate with annular groove 123 in the outer face of the front pump plate, FIG. 5. This annular groove is thus, delivering discharged fluids from the rotor chamber 49 for communication with the pair of angular grooves 125 and 127 formed in the inner surface of the pump casing, FIG. 6.

The one end of the said grooves have restricted axial passages 129 formed through said body which communicate with the transverse bore 131 shown in FIG. 7

across the end of the body. In the illustrative embodiment, the opposite ends of the bore'I31 are closed by a pair of plugs 133.

It is contemplated under some conditions that one of these plugs may be removed and a return line provided for any excess fluids back to a fluid storage sump.

The front pump plate 31 is in snug registry with the inner surface of the body corresponding to the grooves 125 and 127, to provide communication from one of the said grooves to a corresponding inlet 135 and passage 137, FIG. 2 within stator 51 for delivering pumped fluids into the discharge chamber 59.

With the soft valve 63 unseated, due to pressure build up within said chamber, air in the first instance and later liquids are delivered through the ported valve seat 61 into the outlet 139, FIGS. 1 and 2, which communicates with a corresponding passage 141 in the pump front plate and thence to the bore 143 and into transverse passage 145, also shown in FIG. 7. Passage 145 is a discharge passage adapted for connection to a burner nozzle, for illustration, of an oil burner or for any other discharge receiver. The other end of the passage 145 is closed by a plug 149, FIG. 7.

OPERATION It is one of the purposes of the present invention to provide a means of discharging air at relative low pressure into the

nozzle conduit

139, 141, 143 and 145 and into the fire box and at about the same time, providing that when oil reaches the pump that the normal adjustable pressure will be generated. This is accomplished in the following manner:

Flow of oil from the discharge chamber 49 of the pump to the nozzle is accomplished by passing through a cut off valve opening which consists of the seat 61 formed in the cylinder casing 52 through which projects discharge passage 139 in conjunction with the soft valve 63 on the stator slide 51.

As pressure under said slide within delivery chamber 59 builds up from the operation of the pump 39, it tends to lift the soft valve 63 away from its seat, causing the valve to open. This movement is resisted for a short distance by a relatively weak spring referred to as air release spring 69 on the opposite side of the slide for a distance of about 0.015 inches.

The slide then strikes the'spring retainer 67 which is resting on the pump end plates 25 and 31 and further movement is controlled by the heavier adjustable spring referred to as discharge pressure spring 71, FIG.

When the pump first starts up, it is wetted with oil from assembly or its previous operation. The suction line and piping is substantially filled with air. While the orifice in the burner nozzle forms a substantial constriction, it could discharge air or gas to the full volume of the pump at relatively low pressure if it could get by the nozzle shut off valve 63-61.

In the past, this valve has always been closed by the full pressure of the main adjustable spring which is commonly set at 125 pounds. To pump air to this pressure, even in a wetted pump, would require very close tolerances in the displacement used. In the present invention, therefore, the initial movement of the shut off valve for approximately 0.015 inches is controlled by a far weaker spring 67 of approximately 25 pounds pressure. This permits the valve to crack at about that pressure and discharge air out of the nozzle going through discharge passage 139.

However, when solid liquid reaches the pump and nozzle, further pressure is generated due to the inability of the nozzle to pass that volume of liquid, and the slide has to move and overcome the pressure of the main spring 71 in order to reachan equilibrium of volume with the pump discharge.

It is noted that in all cases, the shut off valve 63 is held against its seat 61 by the relatively weak air release spring 67 which is nonadjustable. Heretofore, the valve was held on its seat by a spring which could be adjusted from to 175 pounds operating pressure, and the same valve was used for springs up to 300 pounds operating pressure or more.

The valve, therefore, had to be relatively hard and capable of standing the maximum pressure without permanent deformation. With the present construction since the pressure is lighter and always uniform, a valve most suitable for this pressure alone can be employed.

MODIFICATION The basic idea of an air release through the nozzle at low pressure is equally applicable to the present constant displacement oil motor pumps, such as shown in FIG. 8, which use a piston type of bypass valve to bypass the surplus oil which is pumped but not used at the nozzle. These pumps cannot prime themselves, except on two pipe systems which are costly to install.

A bleed slot is used in the piston type of bypass valve which in a two pipe system permits air to return to the tank and in a single pipe system to the suction side of the pump.

Referring to the schematic illustration, FIG. 8, of such a system, there is provided a positive 'oil burner pump with a modified piston type of bypass valve 169. It has no bleed slot and the cut off would have to be obtained by means of a centrifugal clutch or solenoid valve, either of which has other desirable features.

In FIG. 8 there is illustrated a constant displacement type of pump which includes in a single pipe system 151, a fixed capacity gear pump 153 connected to a suitable pump drive shaft 155 within the pump housing 157 having inlet 159 from a tank of liquid.

Said housing includes outlet 167 adapted for connection to a nozzle of a burner or for other purposes receiving fluids from delivery chamber'163' within the housing. The nozzle shut off valve seat 165, FIG. 8, communicates with the discharge passage 167 to such nozzle.

Nozzle shut off valve 169 has a body in the form of a piston which is movable in a bore which corresponds to and merges with chamber 163. Said valve includes a soft valve 170 adapted nonnally for registry with seat 165 closing off flow of pumped fluids to discharge passage 167.

The annular flange 171 forming a part of piston 169 is normally in registry with such portion of the wall of the chamber as to close off the outlet 172 to bypass conduit 173 in the housing.

The formed spring retainer 175 is nested within the bore which forms an extension of chamber 163 and extends up into the piston valve 169 and is held in such position by the discharge pressure bypass spring 177.

Said retainer, flared at its outer end, is adapted for registry with the stop shoulder 179 in said housing. This end of the spring retainer engages the shoulder under the bias of bypass spring 177 after it has closed the bypass 173 by the movement of the valve 169 to a position above what is shown in FIG. 8. Due to the engagement of the retainer with stop shoulder 179 the soft valve element 170 has not been fully closed against the seat 165, leaving a gap of about 0.015 inches.

This last movement of soft valve 170 is obtained by the much weaker air control spring 185 which is interposed between the inner end of retainer 175 and the shut off valve piston 169, thus forcing the valve against the seat 165. Here again the force is lighter and without adjustment, so a much more resilient valve can be safely used.

At the opposite end of the bypass spring 177 there is provided spring retainer 181 under the control of the adjusting screw 183 threaded into said housing.

OPERATION The operation of the positive pump is as follows: When the pump starts up and the line is full of air and requires priming, it will be pumping full capacity and can readily pump the low pressure needed to overcome an adequate orifice to accommodate the full volume at low pressure.

However when solid liquid reaches the pump 153, and said nozzle, additional pressure is build up through the inadequacy of the small nozzle orifice to handle this substantial volume of liquid, with the result that the piston 169 is forced further outward and eventually must overcome the pressure of the main adjustable spring 177 in order that the piston valve reach the bypass position shown in FIG. 8 and to, thus, stabilize the pressure fluid and with some of the fluid not flowing through the discharge passage returning via the bypass 173 back to the tank.

It will be seen that this construction permits both the variable capacity and fixed capacity pumps, FIGS. 1 and 8, to be self-priming on a single pipe system by discharging the air through the nozzle where it can do no harm. Not only does it eliminate the need for costly two pipe systems, but it also in most cases, eliminates the need for two stage pumps.

Having described my invention, reference should now be had to the following claims.

I claim:

1. In a variable capacity pump having a body with a liquid inlet port and a discharge outlet adapted for connection to a nozzle;

a cylinder within the body formed by a hollow casing,

and front and rear pump plates secured thereto;

a pump stator slidably mounted in said cylinder engaging said pump plates and having an cylindrical opening therethrough;

a rotor with radially movable vanes mounted in said opening with the vanes adapted to move over the boundary of said opening for a pump action, receiving liquid through a port in said rear pump plate and discharging liquid through a port in said front plate;

the improvement comprising a drive shaft mounted and journalled in said body extending through said pump plates and secured to said rotor;

opposed extensions on said stator slidably movable respectively within a radial first slot extending through said casing;

and a radial second slot extending into said casing;

said second slot outwardly of one statorextension defining a discharge chamber adapted to receive pumped fluids;

there being a cut off valve opening in said casing adapted for connection to said discharge outlet;

said cut off valve opening including a seat in said chamber, and a soft valve on one stator extension normally in registry with said seat;

a spring retainer within said pump body normally spaced radially outward of the other stator extension and supported upon said pump plates;

an air release spring interposed between said retainer and said stator extension, yieldably resisting radial outward movement thereof;

and a discharge pressure spring coaxial of and interposed between said retainer and said body normally holding said retainer during initial movement of said stator towards and into engagement with said retainer, so that initial low pressure air delivered to said chamber lifts the soft valve from said seat for delivery to said nozzle;

solid liquid subsequently pumped to said chamber of progressively increasing pressure causing the stator to move further radially outward against the action of said discharge pressure spring, further opening said valve to reach an equilibrium of volume of pumped liquid delivered to 'said nozzle.

2. In the pump of claim 1, said air release spring being relatively-weak responding to pressures in the range of 5 to 35 pounds per square inch, said discharge pressure spring being relatively strong responding to liquid pressure in the range of 50 to 200 pounds per square inch.

3. In the pump of claim 1, said pump body having a chamber loosely enclosing said cylinder defining an annular space around said cylinder communicating with said inlet port; a cover on said body closing said chamber; there being an annular groove on said rear pump plate, in registry with the rear pump plate port.

4. In the pump of claim 3,-said stator being chamfered upon its opposite faces defining inlet and outlet passages; said inlet passages communicating with said rear pump plate port for delivery of fluid to the intake side of said rotor.

5. In the pump of claim 4, said outlet passages receiving pumped fluid from the discharge side of said rotor for delivery to said front plate port and to said discharge chamber.

6. In the pump of claim 5, there being a second axial port in the rear and front pump plates spaced from its respective first port; said second port in said rear pump plate communicating with its annular groove and adapted to communicate with said stator inlet passages; said second port in said front pump plate adapted for communicating with said stator outlet passages and said discharge chamber; said stator adapted to be reversed face to face for respective communication of the inlet passages with the second port in said rear pump plate and communication of the outlet passages with the second port in said front pump plate; there being diammetrically opposed axial bosses projecting from the respective opposite sides of said stator; said bosses selectively closing one port in said rear pump plate and one port in said front pump plate, whereby upon rotation of said rotor in the reverse direction, all that is required is to reverse the position of said stator face to face.

7. In the pump of claim 5, conduit means for delivering pumped fluids from said front plate port to said discharge chamber, said conduit means including a passage in said stator outletting to said discharge chamber, and a slot upon the inner face of said body adjacent said pump front plate in registry with the front pump plate port and with said stator passage.

8. In the pump of claim 7, there being an annular slot in the outer face of said front pump plate in registry with its port and communicating with said body slot.

9. In the pump of claim 7, there being a fluid return axial port in said body inner face in registry with said inner face slot; and a restricted fluid return outlet on said pump body connected to said body port adapted for connection to a fluid storage tank for bypassingof pressure fluid.

10. In the pump of claim 1, a radial boss on said body having a bore receiving said spring retainer and said discharge pressure spring; an adjusting screw nut in said bore retainingly engaging the outer end of said discharge pressure spring; and a discharge pressure adjustment bolt rotatively anchored in said boss and threaded into said nut.

11. In the pump of claim 1, a hardened steel shroud mounted over the rear pump plate; the inner end of said drive shaft having a conical end in axial end through engagement with said shroud. I

12. In the pump of claim 11, an axial boss on said body receiving said drive shaft; an apertured seal cover on the outer end of said boss receiving said shaft;'an -an-' nular apertured seal receiving said shaft seated on the outer end of said boss and anchored by said seal cover;

- from said nosepiece, secured upon said shaft and rotatable therewith; a compression spring between said seal drive and seal face nose piece; and drive means between said seal drive and nose piece, said hose piece being longitudinally movable on said shaft; the thrust of said spring upon said nose piece tending to slide the drive shaft inwardly biasing the shaft conical end against said shroud minimizing friction due to the thrust from said spring.

13. In the pump of claim 1, an axial boss on said body receiving said drive shaft; an apertured seal cover on the outer end of said boss receiving said shaft; an annular apertured seal receiving said shaftseated on the outer end of said boss and anchored by said seal cover; a rotative seal'face nose piece within said boss in engagement on one side with said seal; a seal drive secured upon said shaft and rotatable therewith; a compression spring between said seal drive and said seal face nose piece; and a drive means between said seal drive and nose piece, said nose piece being longitudinally movable on said shaft.

1 4. In the pump of claim 13, and an annular flange on said one side of said nose piece in continuous engagement with said seal throughout 360.

15. In the pump of claim 13, said seal drive means between said seal drive and nose piece being a series of splines.

Claims

1. In a variable capacity pump having a body with a liquid inlet port and a discharge outlet adapted for connection to a nozzle; a cylinder within the body formed by a hollow casing, and front and rear pump plates secured thereto; a pump stator slidably mounted in said cylinder engaging said pump plates and having an cylindrical opening therethrough; a rotor with radially movable vanes mounted in said opening with the vanes adapted to move over the boundary of said opening for a pumping action, receiving liquid through a port in said rear pump plate and discharging liquid through a port in said front plate; the improvement comprising a drive shaft mounted and journalled in said body extending through said pump plates and secured to said rotor; opposed extensions on said stator slidably movable respectively within a radial first slot extending through said casing; and a radial second slot extending into said casing; said second slot outwardly of one stator extension defining a discharge chamber adapted to receive pumped fluids; there being a cut off valve opening in said casing adapted for connection to said discharge outlet; said cut off valve opening including a seat in said chamber, and a soft valve on one stator extension normally in registry with said seat; a spring retainer within said pump body normally spaced radially outward of the other stator extension and supported upon said pump plates; an air release spring interposed between said retainer and said stator extension, yieldably resisting radial outward movement thereof; and a discharge pressure spring coaxial of and interposed between said retainer and said body normally holding said retainer during initial movement of said stator towards and into engagement with said retainer, so that initial low pressure air delivered to said chamber lifts the soft valve from said seat for delivery to said nozzle; solid liquid subsequently pumped to said chamber of progressively increasing pressure causing the stator to move further radially outward against the action of said discharge pressure spring, further opening said valve to reach an equilibrium of volume of pumped liquid delivered to said nozzle.

2. In the pump of claim 1, said air release spring being relatively weak responding to pressures in the range of 5 to 35 pounds per square inch, said discharge pressure spring being relatively strong responding to liquid pressure in the range of 50 to 200 pounds per square inch.

4. In the pump of claim 3, said stator being chamfered upon its opposite faces defining inlet and outlet passages; said inlet passages communicating with said rear pump plate port for delivery of fluid to the intake side of said rotor.

9. In the pump of claim 7, there being a fluid return axial port in said body inner face in registry with said inner face slot; and a restricted fluid return outlet on said pump body connected to said body port adapted for connection to a fluid storage tank for the bypassing of pressure fluid.

11. In the pump of claim 1, a hardened steel shroud mounted over the rear pump plate; the inner end of said drive shaft having a conical end in axial end thrust engagement with said shroud.

12. In the pump of claim 11, an axial boss on said body receiving said drive shaft; an apertured seal cover on the outer end of said boss receiving said shaft; an annular apertured seal receiving said shaft seated on the outer end of said boss and anchored by said seal cover; a rotative seal face nose piece within said boss in engagement on one side with said seal; a seal drive spaced from said nose piece, secured upon said shaft and rotatable therewith; a compression spring between said seal drive and seal face nose piece; and drive means between said seal drive and nose piece, said nose piece being longitudinally movable on said shaft; the thrust of said spring upon said nose piece tending to slide the drive shaft inwardly biasing the shaft conical end against said shroud minimizing friction due to the thrust from said spring.

13. In the pump of claim 1, an axial boss on said body receiving said drive shaft; an apertured seal cover on the outer end of said boss receiving said shaft; an annular apertured seal receiving said shaft seated on the outer end of said boss and anchored by said seal cover; a rotative seal face nose piece within said boss in engagement on one side with said seal; a seal drive secured upon said shaft and rotatable therewith; a compression spring between said seal drive and said seal face nose piece; and a drive means between said seal drive and nose piece, said nose piece being longitudinally movable on said shaft.

14. In the pump of claim 13, and an annular flange on said one side of said nose piece in continuous engagement with said seal throughout 360*.