US3168872A

US3168872A - Positive displacement piston pump

Info

Publication number: US3168872A
Application number: US253475A
Authority: US
Inventors: Harry E Pinkerton
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-01-23
Filing date: 1963-01-23
Publication date: 1965-02-09
Anticipated expiration: 1982-02-09

Description

Feb. 9, 1965 H. E. PINKERTON POSITIVE DISPLACEMENT PISTON PUMP 3 Sheets-Sheet 1 Filed Jan. 23, 1965 INVENTOR. HARRY P/N/(EE'TON ATTORNEYS Feb. 9, 1965 H. E. PINKERTON POSITIVE DISPLACEMENT PISTON PUMP 3 Sheets-Sheet 2 Filed Jan. 23, 1963 INVENTOR. HA RE) E. P/NKEKTO/V fia/ EM Maw 1965 H. E. PINKERTON 3,168,872

POSITIVE DISPLACEMENT PISTONPUMP Filed Jan. 23, 1963 3 Sheets-Sheet 3 F /6'. /4 F 6. l5 Jag 58a

52b

58b

46b

56a 56a 52a 52a /60 we /56 ms 30 be exposed to the chamber on the piston upstroke.

United States Patent 3,168,872 POSITIVE DISPLACEMENT PITON ?UMP Harry E. Pinkerton, R0. Box 387, Mill Neck, N.Y. Filed Jan. 23,19e3, Ser. No. 253,475

' 13 (Eiaims. (Cl. 103-157) Heretofore, a composite of gear, piston and variable .1

vane pumps have been proposed in a variety of forms, including the classical swash plate and wobble plate pumps, slide block pumps as well as others. However, because of their complex nature, such pumps have typically been susceptible to only a limited number of applications where clean filtered hydraulic fluid being pumped bathes all working parts for essential lubrication, heat transfer and shock cushioning. These pumps. are, therefore, rarely applied to routine product handling in the food, chemical and processing industries. In these cases, eithergear, piston, or vane pumps are commonly employed in a number of varieties exemplified by the pumps commercially available today. Unfortunately, these pumps are either not reversible or variable in displacement to mention a few disadvantages. There is also the usual requirement for inlet or outlet check valves which ordinarily detract from the accuracy, longlife and ultimate pump properties and characteristics.

The present invention has, for one of its principal objects, a pump incorporating the optimum and salient features of such prior art pumps without concern withthe enumerated disadvantages by providing a valveless, positive displacement, piston pump capable of producing stepless variable and reversible fluid flow. 1

Another object is to provide a simple positive displacement pump having a rotating and reciprocating ducted pistonand possessing only one moving part, notably the piston, in the pumpfluid stream with valves, pintles, throttles, bearings, springs and other such components being unnecessary.

A further object is to provide a pump of this nature wherein complete handling of substantially any fluid including hydraulic fluid is possible particularly where control of flow rate and/or direction is of importance by the mere proper selection of only two component materials, namely that of the piston and cylinder.

A still further object is to provide such a pump with design simplicity and versatility for a wide number of applications where flow directivity and control of flow rate from zero to maximum in either direction is desired particularly from a constant speed, uni-directional power source. 7

Still another object is to provide such a pump for applications where system costs, variable flow, valve-problems, pumping eificiency, flow reversal or gland leakage are significant factors.

A pump incorporating the teachings of the present invention employs a ducted piston which reciprocates and rotates synchronously in a bi-ported'cylinder. The piston duct is so arranged as to connect the ports alternately with the pumping chamber. Under such circumstances, one port will communicate with the pumping chamber on the down stroke of the piston whereas the other port will Reversal of duct timing resultsin reversal of flow direction. Essentially, at least three cylinder-piston arrangements are contemplated for establishing the foundationfor pump versatility thereby covering a majority of modern day fluid handling requirements. Each arrangement lends it- "Ice self advantageously to gland scavenging whereby piston and gland bypass fluids can be returned at negative pressure to .the suction side of the pump system or directly to the fluid source at atmospheric pressure. Thus, gland leakage problems are effectively eliminated. Multiple units in monophase or multiphase relationships are also contemplated for providing a wide variety of output characteristics ranging from the typical pulse and suck mode of valve type piston pumps to substantially constant flow. It should be understood that all models are valveless and variable; and all can be arranged in uni-directional or reversible flow. As will be explained in detail, the three basic cylinder-piston arrangements are, respectively, termed monoplex, double monoplex and duplex.

In one embodiment of this invention, a piston-cylinder assembly is coupled with the output of a drive motor through an interposed collar or yoke. The piston includes at its outer end a laterally projecting arm having a ball hearing which is adapted to ride in a socket in the collar to thereby provide a universal joint between these parts. A cylinder conveniently receives the piston and is mounted on a bracket rotatable about a vertical axis. The cylinder is provided with at least one pair of ports both of which communicate with the cylinder pumping chamber.

When the axis of the collar and that of the piston and cylinder are substantially coaxial, the piston does not reciprocate in the'cylinder during rotation of thecollar. Under such circumstances, no pumping action takes place. When the cylinder is rotated about its pivot, the piston will rotate at a corresponding amount relative to the collar. The direction of rotation, that is either clockwise or counterclockwise, determines the direction of feed. The magnitude of rotational movement determines the amplitude of piston stroke and, consequenty, flow rate.

In another embodiment, contemplatedby this invention, the yoke rather than the cylinder is pivotal. Under these circumstances, the outer end of the piston includes a collar having a splined connection with the output shaft of the drive motor. Thus, when the yoke is pivoted in one direction or the other, an eccentric elliptical path of travel of the ball in the yoke socket is induced, with the reciprocating movement of the piston at its coupling with the output shaft being compensated for by the splined connections. It should be understood in passing that other connections between the piston and motor drive are contemplated in providing the valveless,

reversible and variable pump of this invention and such are embraced by the protection afforded herein.

Other objects and advantages will become apparent from the following detailed description which is to be taken in conjunction with the accompanying drawings illustrating preferred as well as exemplary embodiments of this invention and in which:

FIG. 1 shows a basic monoplex pump coupled with the output shaft of a drive motor with certain parts broken away and removed and sectioned;

FIG. 2 is an enlarged fragmentary top plan view of this pump with certain parts broken away and removed and sectioned;

FIG. 3 is a similar ,view with the pump adjusted to provide reverse fluid flow;

FIG. 4 is an enlarged fragmentary cross sectional view taken along the line 44 of FIG. 2;

FIGS. 5 to 8 are fragmentary perspective views par tially sectioned showing the sequence of operation of the pump of'FIG. 2 and the steps transgressed by the piston during the pumping cycle;

FIGS. 9 to 12 are similar views showing the sequence of operation of the pump of FIG. 3;

FIG. 13 is a diagrammatic fragmentary view of a basic monoplex pump illustrated in the preceding figures;

FIG. 14"is a similar view of a basic double monoplex FIG. 15 shows a basic duplex pump;

FIG. 16 shows a scavenger monopl-ex pump;

'FIG. =17 shows a scavenger double monoplex pump;

FIG. 18 shows a scavenger duplex pump;

FIG; 19 shows a multiple monoplex pump; 7

FIG. 20 shows a multiple double monoplex pump;

FIG. 21 shows a multiple duplex pump;

FIG. 22 is a fragmentary perspective view with cer tain part designated with phantom lines of another embodiment of pump of this invention; and

FIG. 23 is a longitudinal sectional "view of this pump.

Refer now to FIGURE 1, a positive displacement piston pump 39 this invention is shown coupled with the output of a drive motor 32, both of which are mounted on the platform support 34. Naturally, the support will vary'depending upon the selected pump application. The motor is secured to the support by mean of the suitably anchored motor bracket 36. The pump 39, on the other hand, is provided with an angle bracket 3%, leg 4% of which rests on the support 34 and is coupled thereto by means of the pivot pin =42. The bracket leg 44 has suitably secured thereto the open end of the cylinder 46. Piston '48 extends through bore 50 provided in the bracket arm 44 into the interior of the cylinder.

The inner end of the piston 48 is provided with a cutout or recessed portion 52 functioning as a duct which together with the cylinder interior at thehead of the 'piston, cooperates in forming the cylinder pumping chamber 54, The cylinder is provided with ports, 56 and 58 (see FIGS. 2 and 3) adapted to perform as both inlet and outlet ports and communicate with the pump chamber 54. Tubing may be suitably coupled with these ports as part of the circuit or systemior fluid to be pumped.

As 'will be'readily appreciated, the forward end of the piston 48 is adapted to close off or seal each port depending upon the extent of relative rotation of the piston in the cylinder. On the other hand, the duct 52 is adapted to simultaneously expose the pumping chamber 54 to the other port to permit free passage into the chamber of the pump iiuid. The piston head operates toshear the fluid on the suction stroke as it rotates in the 'path past the ports. No suction check valve is needed since outlet pressure is never felt at theinlet port. Similarly, the outlet port is never open to the inlet, therefor, a discharge check is not necessary. The pumping cycle and sequence of operation of the pump will be explored in detail shortly.

The outer end of the piston 48 has secured thereto a laterally projecting drive pin or arm 57. A ball 59 is securedto the outer terminal end of this arm 57 and forms part of a universal ball and socket joint. In this connection, 'a collar or yoke 69 mounts the socket part 62 of .this joint. A reduced boss 54 extends concentrically from the collar fitland is adapted to be keyed to the motor output shaft 66.

When the yoke lliis disposedin a substantially coaxial relationship with respect to the piston 48 in a manner substantially designated by FIG. 1, the piston will have no stroke nor will it reciprocate upon energization of the motor 32 and, consequently, rotation of output shaft66 and the yoke 60. Under such circumstances, no pumping action takes place. When the'cylinder is pivoted about its pivot pin 42 which, incidentally, is aligned with the vertically extending axis of the yoke 60 in a counterclockwise direction, as viewed'in FIG. 2, the piston 48 will be pivoted a corresponding amount. Assumingthe depicted rotation of the motor output shaft 65, the elliptical path of travel of the ball 59 and induced reciprocation of the piston 48 will cause the pumping fluid to be pumped out fromthe pumping chamber 54through the port 58. In this connection,the port 56 will function as the inlet port; Pivoti'ng of the cylinder 46 in a clockwise direction, as shown in FIG. 3, will reverse fluid flow.

7 upon the degree of pivoting of the cylinder.

The magnitude of pivotal movement of the cylinder will determine the amplitude of piston stroke and, consequently, the rate of fluid flow.

The cycle of operation of the pump 30, when disposed in the manner illustrated in FIG. 2, is shown clearly in FIGS. S'through 8. Thus, in FIG. 5 as in FIG.'2, the piston will be at the end of its retraction or backstroke at which the pump chamber 54 is in communication with the outlet port'58 with the inlet port 56 sealed by the head of the piston 48. The continuously rotating piston will then be forced for-wardlyinto the cylinder '46 thereby forcing the fluid out from the chamber 54 through the outlet port "58 as a result of passage afforded by the duct 52, as shown in FIG. 6. When the piston traverses .180 rotational'dis'placement, the piston will either bottom or stop short of the bottom of the cylinder 46 depending At this time, the piston will be disposedv at the beginning of its retraction stroke at which the outlet port 58 is sealed by the piston head and the ducts 52'open the pumping chamber 54 to the inlet port 56, as'illustrat'ed in FIG. 7. As the piston 48 is retracted or withdrawn in the cylinder 46, the created suction will forcethe pumping fluid into the expanding plumpinglchamber 54 through the duct 52 from the inlet port 55, as shown in FIG. 8, until such time as the piston is disposed in the cylinder at the start of the cycle, as represented in FIG. 5. The inlet port 56 will, at this point, be sealed by the piston head; and the pumping chamber 54 will be in communication with the outlet port 58 by means of the interposed ductSZ.

When the cylinder is pivoted 'in aclockwise direction, as shown in FIG. 3 and as represented 'by E1629, the piston 48 will be bottomed or at the beginning of the suction part of the pumping cycle.' The port 58, under such circumstances, will be the inlet port with port 56 serving as th outlet. At the start of the cycle, the outlet port 56 will be sealed by the piston head and the inlet port 5% opened to' permit introduction of the pumping fluid through the duct 52 into the pumping chamber 54. As the piston 48 rotates, it will be retracted, as shown in FIG. 10, such that the created suction will force the-pumping fluid into the chamber S through the space afforded by the duct 52; When the piston has rotated the inlet port 5 8 will be sealed by the piston head and the outlet port 5% opened and the piston will be disposed at the end of its retraction stroke andbeginning of its forwardpumping stroke, as shown'in FIG. 11. Accordingly, the piston willthen be forced inwardly of the cylinder 46 whereby the pumping fluid in the chamber 54 will be forced through the duct 54 out through the outlet port 56, a depicted by FIG. 12, until the start of the cycle is reached at which the disposition of parts is that illus trated in FIG. 9. With the foregoing in mind, the operation of the'several contemplated pumps illustrated in FIGS. 13 to 21 will be readily apparent. With respect. to the monoplex pumps, typified by FIGS. 13, 16 and 19, the changes from pumping to suction phase and from suction to pumping phase are not accompanied by valve suck back losses because'of the elimination of check valves. Thus, metering values are more accurately predictable and reproducible with these units than with valve type piston metering pumps. These pumps are single acting units that pump with single phase, half sign wave output characteristics.

In FIG. 16, the basic monoplex pump is shown with incorporated scavenging means '70. In this embodiment, those part corresponding to those previously discussed will be similarly numbered with accompanying primes. In this embodiment, rod and gland scavenging'is facilitatedwhereby piston and gland bypass iluids can be returned at negative pressure to the suction side of the fluid system or directly to the fluid source at atmospheric pressure, thus eliminating gland leakage problems.

In FIG. 19, a multiple pump unit in monophase relationship'is provided in which the half sign wave out-put characteristics of each are superimposed to provide a substantially single phase rectified full Wave fluid output characteristic. In this embodiment of the twin monoplex pump, each pump is arranged to pnovide for uni-directional or reversible flow. Since the basic pump unit of this embodiment corresponds with that of FIG. 13, the parts will be similarly numbered. It should be understood, as is likewise the case with the other versions of multiple pump to be discussed, that more than two pumps may be employed in an effort to obtain the desired flow patternand characteristics. In addition, suitable means may provide for identical piston stroke and reciprocation or piston reciprocation in a prescribed ratio.

With respect to the double 'monoplex pumps exemplified by FIGS. 14, 17 and 20, two separate compatible fluids can be handled simultaneously at proportionate flow rates. These pumps may either have equal chamber and duct capacites at both ends of the rotatable and reciprocal piston or specified chamber and duct ratios. As is evident, either midchamber or rod end scavenging versions of this pump are possible. a

In the double acting pump of FIG. 14, the cylinder 46:: contains the rotatable and reciprocal piston 43a which includes at both of its interior ends ducts 52a each of which serve to open and close during the pumping cycle, two pairs of

ports

56a and 58a. The clearance provided between the end of one duct and the beginning of the next is determined by the diameter of the opposed ports in the cylinder and is ordinarily this dimension or larger. The output flow characteristics resemble essentially a single phase rectified full wave. These double acting pumps can obviously be operated at negative pressures for piston packing glands while head pressures are highly positive. This may be accomplished by operating the packing gland end of the piston as a feeder tor the head pressure end of the piston. By the same expedient, this double acting unit can be used as a blender, drawing from two, separate solution sources simultaneously and discharging the mechanically mixed product of the two sources into a single discharge port.

In the double monoplex scavenger pump of FIG. 17, a scavenging means 749a is incorporated at the rod end of the cylinder. The remaining parts or components will find their counterparts in the embodiment of FIG. 14 and, for this reason, will be similarly numbered with accompanying primes. r

In the twin double monoplex pump of FIG. 20, a rectified multiphase flow transfer characteristic is provided. As the number of individual pump units of this version increases, a broad range of flow characteristics are possible. Since the individual pumps of this composite unit are essentially the double monoplex pump of FIG. 14, the parts will be similarly numbered.

Referring now to the duplex pumps illustrated in FIGS. 15, 18 and 21, it should be initially appreciated that these pumps otter optimum single piston pumping characteristics with a two port arrangement. The pumping efiiciency of this pump is extremely high and, due to the sharp flow cutoff at the end of each half cycle, ripple suppression of both input and output may be effected through relatively low volume accumulators. These duplex pump units are exceptionally versative and work equally Well in compressonyalve, flow regulator and pump applications. In the basic duplex pump of FIG. 15, a cylinder 46b contains the rotatable and reciprocal piston 48b having at both of its interior ends a somewhat elongated duct 52b. The clearance provided between the end of one duct and the beginning of the next is determined by the, diameter of the opposed ports in the cylinder and is ordinarily this dimension or larger. The chambers at both of the piston ends will alternatively serve in a pumping and suction capacity in transferring the pumping fluid between the

opposed ports

56b and 58b. The flow characteristics of this version is essentially single phase rec'- tified full wave.

In the duplex scavenger pump of FIG. 18, a scavenging means 70b is incorporated in the unit at the rod end of the piston. The remaining parts of this pump find their counterpart in the pump of FIG. 15 and, consequently, will be similarly numbered.

The twin duplex pump of FIG. 21 representing one version of a wide range of multiple pumps is made up of individual pump units corresponding to the basic duplex pump of FIG. 15. Accordingly, like parts will be similarly numbered. These multiple pump units produce a broad range of rectified multi-phase transfer characteristics.

In the multiple purnps, FIGS. 19, 20 and 21, the individual pumps are preferably interconnected by means which enable them to pivot a corresponding amount thereby permitting their respective pistons to reciprocate proportionately. Naturally, if desired, this pivotal movement can be equal or in terms of some prescribed ratio;

In FIGS, 22 and 23, another embodiment of valveless positive displacement pump capable of producing reversible as well as stepless variable flow is disclosed. Accordingly, a cylinder 146 advantageously contains a rotatable and reciprocal piston 14%. This piston includes an outwardly extending piston rod 149'also adaptedto rotate and reciprocate with respect to the opening 150 in the rear of the cylinder 146. As an exemplary embodiment, the pump 130 serves as a basic duplex pump corresponding to that disclosed in FIG. 15. Thus, both ends of the piston 148 are provided with ducts 152. In lieu of the single cutout for providing this duct, as suggested in the previous embodiment, a series of elongated slots, cutout or recessed portions may be employed. .In addition, a combination of an enlarged cutout portion similar to the previous embodiments together with these slots may be employed, it being understood that this invention contemplates many other configurations and combinations of ducts for accomplishing the intended objects and purposes. Both ends of the piston 148 provide with the interior cylinder Walls spaced and distal pumping chambers 154 which are adapted to alternatively communicate with the

ports

156 and 158 by means of the ducts 152 in generating the intake and output phases of the pumping cycle.

The terminal end of the piston rod 149 is provided with a laterally extending arm 157 the end of which conveniently mounts a ball 15h. This ball is adapted to cooperate with pivotal yoke 166) by riding in a circumferentially extending internally slotted raceway 162. The outer end of the piston rod 149 additionally includes a collar 164 which is coupled with the output shaft 166 of the motor drive 132. .The coupling of the collar and motor shaft is such as to render the piston rod 149 and, consequently, the piston 14% and cylinder 146 coaxially and permanently aligned with the output shaft. In order to obtain reciprocation of the piston 143 upon rotation of the motor output shaft 166, as well as reversibility of fluid flow, the yoke is permitted pivotal movement with respect to the rotational axis. In the exemplary embodiment, this pivotal movement is about a vertically extending axis. Assuming rotational movement and pivotal displacement of yoke 160 in a clockwise direction, as viewed in FIG. 23, the pumping fluid in the rear chamber 154 will flow through the rear piston ducts 152 out through the port 158. Simultaneously, therewith, the

' front chambers 154 will take in pumping fluid through the front piston ducts to the port 156. When the retraction stroke of the piston 148 has ended and the forward stroke begins, the fluid in the front cylinder chamber will be' pumped out through the port 158 and the rear chamber 154 filled with pumping fluid emanating from the port 156. Pivoting of the yoke 160 in acounterclockwise direction, as viewed in FIG. 23, will provide for reversal of fluid flow.

In order to maintain the coaxial relationship of the drive train, a spline connection means 168 is provided between the'collar 164 and motor drive shaft 166. This ,7 spline connecting means 168 may take the form of splines provided in the opposed surfaces of the collar interior and shaft exterior. Thus, the collar is provided with splines 17% whereas the shaft is provided with the splines 172. The associated splines are then interconnected with the interposed ball bearings 174. Accordingly, reciprocation of the piston and, consequently, the piston rod 149 will be taken up at the spline connecting means 168 and the rotational movement of the parts still maintained.

It will be readily obvious that the degree of rotation of the yoke 160 will determine the piston stroke and, consequently, the pumping rate. In addition, the means for obtaining variable degrees of piston reciprocation, as well as reversibility of flowof this embodiment, can

in FIGS. 13 through 21 as well as others. 1

In actual practice, pumps of this'invention are capable of flow rates from a few cubic centimeters per hour to hundreds of gallons per minute. Pressures attainable vary from inches of water to thousands of pounds per square inch. Component parts of the pumps can be manufactured from metals, plastics or cermets as well as other materials. 1

Basic simplicity is thusly provided by the pumps of this invention without limiting their versatility and application. These pumps can be employed for metering small or large fiows in virtually any head to suction relationship, namely, positive head pressure, negative suction pressure; zero head to zero suction; negative head, positive suction.

A pump incorporating the teachings of the present invention has particular application in the food and medical industries because they are readily adapted to meter and pump fluids while maintaining purity. Without check valves which clog, causing. cavitation and failure, the pumps can handle blood and other suspensions, as well as slurries and pastes effectively while providing many years of trouble-free service. In a multiple pump unit, one pump can proportion all of the ingredients of a constant mix or several pumps driven from one motor can vary the proportions of many mixtures while assuring simultaneous injection of every ingredient. With infinite turned down ratio, relatively minute quantities of additive such as spices and preservatives can be proportioned into food mixes; thick antibiotics'can be pumped into ampules for the pharmaceutical industry.

These pumps have utility in instrumentation service where metering and pumping of fluids while maintaining product purity is desired or dictated. Small orifice, needle valve openings and other components sensitive to contamination can be supplied with pure, clean fluids for their operation. The variable flow pattern of the pumps is especially suited for accurate control of actuator'traveler valve operator position. In fluid power systems, the reverse capability to full reverse flow permits forward and backard flow at rates equal to each other. Without check valves which cause cavitation and failure, the pumps are insensitive to minor grit and other impurities in hydraulic fluids.

The pumps also have application to the chemical, petroleum, marine and general manufacturing industries where metering and pumping of fluid while maintaining automatedbakery, the lard, water, spices, preservatives and vitamin concentrates would be automatically added to the continuous flour mix. Each additive rate would be controlled independently at a central control panel in precise volumetric relationship'to product requirement. All pistons and cylinders would be hand removable for periodic cleaning and sterilization.

In a chemical processing plant, mechanically coupled pumps of this invention could provide, from a single power source, system command control facility on a positive hydraulic basis in the positioning of gates, diverters and other such system mechanisms. Other pumps could meter additives and trace materials into the main flow. The main fiow could be precisely moved by slave pumps responding to flow rate and pressuredernands of the command units. Valve clogging slurries and semi-solids would be handled directly by pumps of this invention without danger of valve failure or centrifugal separation of product. 7

It will be noted that the duct and port relationship herein described acts in a true shearing manner. Thus, in sewage and waste handling applications, pumps of this invention, particularly those equipped with multiduct .pistons as illustrated in FIGURES 22'and 23, provide unique facility for shredding and pulping of fluid-borne solids.

- Provided with sharp duct and port edges of hard material such as tungsten carbide, these pumps would reduce suspended solids and waste materials. such as paper and fabric to predetermined maximum size for precise chemical treatment and optimum disposal and, at the same time, would perform the essential transfer function Without danger of clogging.

In a prime mover application, such as a bull doz'er, the engine could drive mechanically coupled pumps of this invention to provide independently controlled motive power, steering, blade adjustment, winch operation as well as other functions. Obviously, clutches, shafts, valves, brakes, gear changers and other such presently used system parts would be eliminated. less variation of work rates to meet varying load requirements would enhance operating control and machine capability. The pumps could also be applied to com- .pression of gases with particular advantages in that the power source canbe started againstzero load and then be brought on to the line after sustaining velocities have been reached. System back-pressure can be employed to directly servo'pumping rates precisely to demandrates and since no valves or bypasses are involved, power consumption in continuous operation can be dramatically reduced. The doubleactingpiston pumps previously described in feeder arrangement provide an extra measure of leakage protection through negative packing gland pres- I sures in the handling of controlled gases.

purity is desired. The pumps, as stated, are reversible slurries as easily as clear fluids, and give years of trouble free service. Internal parts can be readily removed for cleaning, ifnecessary. 4

In specific application considerations, the versatility of the pumps become particularly significant. A- typical food application would employ a single electric motor to provide independentlycontrollable insertion of all required additives in a continuous mix system. For example, in an i If it is desired to provide a variable rate of rotation other than some preselected or prescribed value, a potentiometer or the like control can be employed for varying the motor output. Under such circumstances, a gear reduction system need not be employed.

Thus, among others, the aforenoted objects and advantages are most effectively attained. Although somewhat preferred embodiments have been disclosed herein,

itshould be understood that this invention is in no sense limited thereby and is to 'be determined by the communicable with said port means for transferof said,

fluid to andfrom the cylinderydrive means for said .piston having an axis; means for'permitting said piston to reciprocate in said cylinder while rotating, in atimed ,relation; with respect'to said port means; and means for reversing such timed relationship, said reversing means In addition, smooth step being operable to reverse the relative angularity between said axes to obtain fluid flow reversal.

2. A single valveless, reversible, variable fluid flow, positive displacement metering pump comprising in combination: a'cylinder having port means for pump fluid; a piston in said cylinder; duct means on said piston communicable with said port means for transfer of said pump fluid to and from the cylinder; means for coupling said piston to a source of rotational energy for rotating said piston; means for reciprocating said piston while rotating, in a timed relationship with respect to said port means to cyclically open and close said port means; means for varying. the extent of relative reciprocation of said piston; means for reversing said timed relationship; and scavenging means for removing pump fluid that escaped between the associated walls of the piston and cylinder, such latter means including a passage in direct communication with the interior of said cylinder, said passage being adapted to receive the escaping pump fluid upon reciprocation of the piston.

3. A valveless, variable fluid flow, positive displacement pump comprising in combination: a cylinder having a pair of ports for pump fluid; a rotatable and reciprocal piston having opposed ends in said cylinder adapted to provide with the cylinder interior a pump chamber at each end thereof, each of which chamber is adapted to vary in size upon reciprocation of said piston; a pair of duct means on said piston, each of which are in opposed relationship and located at the piston ends, each of said duct means being in communication with one of said ports for transfer of said fluid to and from the associated chamber; means for permitting said piston to reciprocate in said cylinder, while rotating, in a predetermined relationship with respect to said ports to alternately communicate each of the duct means with the other of said ports; and means for varying the extent of relative der having an inlet and outlet port; a piston reciprocally and rotatably disposed in said cylinder and being formed with a duct means communicable with each of said ports; drive means adapted to be coupled with a source of rotational energy for cooperating to rotate said piston in said cylinder; actuator means for reciprocating said piston upon operation of said drive means whereby fluid is drawn into said cylinder through said duct means from one of said ports and then out of said cylinder through said duct and out through the other of said ports; fluid flow reversing means for reversing such fluid flow by reversing the intake and output functions of said ports; and scavenger means for removing fluid that escaped between the associated walls of the piston and cylinder,

such latter means including a passage in direct communication with the interior of said cylinder, said passage being adapted to receive the escaping pump fluid upon reciprocation of the piston.

5. The invention in accordance with claim 4 wherein said cylinder is provided with at least two pairs of said ports, and said piston is provided with a corresponding number of duct means each of which being cooperable in transmitting fluid between the associated pair of ports.

6. The invention in accordance with claim 4 wherein the piston is provided with another duct means adapted to communicate with said ports for supplementing the transfer of fluid by the other duct means.

7. A piston for a reversible, variable flow positive displacement pump comprising a cylindrically shaped piston body having cylindrical side walls and a first and second end, a first duct means formed in said side walls at said first end for providing passage of pump fluid, a second duct means in said side walls at said second end for providing passage of pump liquid, and at least one of said duct means comprising a series of spaced and parallel elongatedrecessed portions extending from a point intermediate the ends of the body to the associated piston end.

- 8. A single valveless positive displacement pump comprising in combination: a cylinder having port means for pump fluid; a piston reciprocally disposed in said cylinder; duct means on said piston communicable with said port means for transfer of said pump fluid to and from the cylinder; means for coupling said piston to a source of rotational energy; actuator means for reciprocating said piston upon operation of the source of rotational energy through the coupling means whereby fluid is drawn into said cylinder through said duct means and then out of cylinder through said duct means through said port means in a timed relationship such that said port means is cyclically opened and closed by said piston, and

scavenger means for removing fluid that escaped between the associated walls of the piston and cylinder, such latter means including a passage in direct communication with the interior of said cylinder, said passage being adapted to receive the escaping pump fluid upon reciprocation of the piston.

9. A valveless pump comprising in combination: a cylinder having an inlet and outlet port; a piston reciprocally and rotatably disposed in said cylinder and being formed with a duct means communicable with each of said ports; drive means adapted to be coupled with a source of rotational energy for cooperating to turn said piston in said cylinder; actuator means for reciprocating said piston upon operation of said drive means whereby fluid is drawn into said cylinder through said duct means from one of said ports and then out of said cylinder through said duct means and out through the other of said ports, said actuator means comprising pivotal means .for changing the angular relationship between the axis of the piston and said drive means to change the stroke of thepiston and vary the fluid flow, said pivotal means pivotally supporting said cylinder such that said cylinder is pivotal about a vertical axis, an arm extending laterally from the exterior end of said piston, a cylindrical yoke coaxially coupled with the rotational output of said drive means; and a universal ball and socket joint means coupling the terminal end of the arm and the yoke whereby upon pivotal movement of the cylinder to a position at an angle to the axis of the yoke, the ball of the joint traverses a substantially elliptical path of travel in a plane normal to the axis of said piston thereby reciprocating said piston while it turns.

10. A valveless pump comprising in combination: a cylinder having an inlet and outlet port; a piston reciprocally and rotatably disposed in said cylinder and being formed with a duct means communicable with each of said ports; drive means adapted to be coupled with a source of rotational energy for cooperating to turn said piston in said cylinder; actuator means for reciprocating said piston upon operation of said drive means whereby fluid is drawn into said cylinder through said duct means from one of said ports and then out of said cylinder through said duct means and out through the other of said ports, said actuator means including a pivotal yoke for changing the stroke of the piston and varying the fluid flow; and coupling means for the piston and drive means, said coupling means being operable to maintain the angular relationship between the axis of the piston and drive means constant, said coupling including a splined connection 'between the exterior of the piston and the rotational output of said drive means such that relative reciprocation is permitted therebetween While the angular relationship is maintained therebetween upon pivoting of the yoke means, the splined connection inat an angle less than 90 to the axis of said piston, the

ball traverses a substantially elliptical path of travel in means whereby fluid is drawn into said cylinder through said duct means from one of said ports and then out of said cylinder through said duct means and out through the other of said ports; and scavenger means for removing fluid from the interior of the cylinder that escapes between the associated walls of the piston and cylinder.

12. A pump comprising in combination: a cylinder having an inlet and outlet port; a piston reciprocally and rotatably disposed in said cylinder and being formed with a duct means communicable with each of said ports; drive means adapted to be coupled with a source of rotational energy for cooperating to rotate said piston in said cylinder; actuator means for reciprocating said piston upon operation of said drive means whereby fluid is drawn into said cylinder through said duct means from one e f said ports and then out of said cylinder through said "duct and out through the other of said ports, said actuator means comprising pivotal means for changing the angular relationship between the axis of the piston and said drive means, said pivotal means pivotally supporting said cylinder such that saidcylinder is pivotal about a vertical axis, an arm extending laterally from the exterior end of said piston, a cylindrical yoke being coaxially coupled with the rotational output of said drive means; and a universal ball and socket joint means -ccu-' pling the terminal end of the arm and the yoke whereby upon pivotal movement of the cylinder to a position at an angle to the axis of the yoke, the ball of the joint traverses a substantially elliptical path of travel in a plane normal to the axis of said piston thereby reciprocating said piston while it rotates; fluid flow reversing means for reversing such fluid tlow by reversing the intake and output functions of said ports; and scavenger means for removing fluid that escaped between the associated walls ot'the piston and cylinder.

13. A pump comprising in combination: a cylinder having an inlet and outlet port; a piston reciprocally and rotatably disposed in said cylinder and being .formed with a duct means communicable with each of said ports; drive means adapted to be coupled with a source of rotational energy for cooperating to rotate said piston in said cylinder; actuator means for reciprocating said piston upon operation of said .drive means whereby fluid is drawn into said cylinderfthrough'said ductmeans from one of said ports and then out of said cylinder through said duct and out though the other of said ports; coupling means being provided for maintaining the angular relationship betweenthe axis of the piston and drive means and the axis of rotation constant, and a pivotal yoke means for changing the relationship between the duct means and 'ports, the coupling means including 'a splined connection between the exterior end of the :piston and the rotational outputof said drive means such that relative reciprocation is permitted and a coaxial relationship is maintained therebetween, said piston including a laterally extending arm having a ball hearing at its terminal'end, said yoke means including an internal raceway in which said ball is adapted to travel, whereby upon pivotal movement of said yoke means to a position at an angle less than to theaxis of said piston, the

ball traverses a substantially elliptical path of travel in a plane at said angle to the axis of said piston while said piston rotates; fluid flow reversing means for reversing such fiuid'flow by reversing the intake and output functions of said ports; and scavenger means for removing'fluid thatescaped between theassociated Walls of the piston and cylinder.

' 1 References Cited by theExaminer UNITED STATES PATENTS LAURENCE V. EFNER, Primary Examiner.

WARREN E. CQLEMAN, Examiner.

Claims

1. A SINGLE VALVELESS REVERSIBLE POSITIVE DISPLACEMENT PUMP COMPRISING IN COMBINATION: A CYLINDER HAVING PORT MEANS FOR PUMP FLUID; A ROTATABLE PISTON IN SAID CYLINDER, SAID PISTON HAVING AN AXIS; DUCT MEANS ON SAID PISTON COMMUNICABLE WITH SAID PORT MEANS FOR TRANSFER OF SAID FLUID TO AND FROM THE CYLINDER; DRIVE MEANS FOR SAID PISTON HAVING AN AXIS; MEANS FOR PERMITTING SAID PISTON TO RECIPROCATE IN SAID CYLINDER WHILE ROTATING, IN A TIMED RELATION WITH RESPECT TO SAID PORT MEANS; AND MEANS FOR REVERSING SUCH TIMED RELATIONSHIP, SAID REVERSING MEANS BEING OPERABLE TO REVERSE THE RELATIVE ANGULARLY BETWEEN SAID AXES TO OBTAIN FLUID FLOW REVERSAL.