Abstract:
A peristaltic pump utilizing a fluid inlet from a source of fluid which communicates with a flexible conduit. The flexible conduit is compressed utilizing a motor which rotates a shaft. An eccentric member is locked to the shaft and contacts the inner race of a bearing which is circumferentially located relative to the eccentric member. The outer race of the bearing contacts a lifter which squeezes the conduit against a fixed plate. A check valve arrangement assures flow through the conduit in one direction.

Description:
BACKGROUND OF THE INVENTION 
     Peristaltic pumps have been devised to provide a steady flow of fluid through a conduit by pressing a member along the length of the conduit. In the past, moveable members have been rolled along the length of the conduit to squeeze fluid from the same in aliquot amounts. For example, U.S. Pat. Nos. 5,064,358 and 5,620,313 describe this type of peristaltic pump. Unfortunately, such peristaltic pumps have suffered from low pressure outputs and pulses or surges which render such pumps as unsuitable for analytical, preparatory or other uses. 
     U.S. Pat. Nos. 4,365,943 and 5,033,943 show peristaltic pumps having low flow rates which utilize a rotating shaft to turn a cam that either directly or indirectly contacts a plurality of flexible conduits sequentially. In either case a relatively small portion of such flexible conduits are deformed to produce the flow. 
     A peristaltic pump which exhibits high flow rate characteristics and eliminates surge would be a notable advance in the field of mass transport. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention a novel and useful peristaltic pump for delivery of fluid from a source is herein provided. 
     The pump of the present invention utilizes a fluid inlet which passes fluid from a source such as a reservoir. The fluid inlet communicates with a flexible conduit having an elongated dimension. Such flexible conduit further includes a fluid outlet. In many cases, a plurality of flexible conduits may be employed and are located in spaced relationship from one another. 
     Compressing means is also used for pressing the flexible conduit or conduits. Such compressing means utilizes a motor and a shaft which is axially rotated by the motor. A first eccentric member is locked to the rotating shaft, and a plate is located adjacent the flexible conduit. In opposition to the plate is a conduit lifter which is capable of being positioned adjacent the flexible conduit and being moved toward and away from the flexible conduit. The conduit lifter, thus, sandwiches or squeezes the flexible conduit to the stationary plate to cause flow of fluid through the flexible conduit. A first bearing having an inner race contacts the first eccentric member. The outer race of the first bearing engages the conduit lifter. Thus, rotation of the eccentric member moves the bearing into contact with the conduit lifter to squeeze the conduit during certain portions of rotation of the shaft of the motor. Such squeezing or collapse of the flexible conduit, in part, against the plate causes fluid to flow through the conduit. Check valve means directs flow of the fluid in one direction. 
     In certain embodiments of the present invention, the conduit lifter may include at least one protuberance which extends toward and contacts the outer race of the first bearing. Where a second bearing is employed, the conduit lifter may include a second protuberance contacting the outer race of the second bearing. In such a case, the second bearing would also be located in circumferential relationship with a second eccentric member locked to the shaft of the motor. Thus, a pair of bearings would operate a single conduit lifter to cause flow through the conduit in this embodiment. 
     In addition, where a second flexible conduit is employed in the present invention, the first eccentric member may support at least another, or third, bearing which would contact a second conduit lifter radially separated about the axis of the shaft from the first conduit lifter. Separation between the flexible conduits and associated lifters may be determined in order to pump fluid through the second conduit when the first conduit has already begun discharging of fluid. Thus, a continuous flow of fluid is obtained from the pump of the present invention. In addition, more than two conduits may be employed in the present invention in sequential fashion, each conduit being operated by a single shaft and by both eccentric members. Again, bearings may independently contact each conduit lifter associated with each flexible conduit about the axis of rotation of the shaft of the motor. Locking collars may hold the multiple bearings location relative to each of the eccentric members. Locking collars may also be located about the motor shaft and about the outer surface of any of the eccentric members. 
     It may be apparent that a novel and useful peristaltic pump has been described hereinabove. 
     It is therefore and object of the present invention to provide a peristaltic pump for delivery of fluid from a source that utilizes a multiplicity of flexible conduits which are sequentially activated to produce steady flow of fluid. 
     Another object of the present invention is to provide a peristaltic pump for delivery of fluid from a source which is capable of delivery of fluid at relatively high pressures. 
     Another object of the present invention is to provide a peristaltic pump for delivery of fluid from a source which greatly eliminates surge or pulsation associated with the flow of fluid from peristaltic pumps of the prior art. 
     A further object of the present invention is to provide a peristaltic pump which utilizes multiple eccentric members located on a shaft to operate a single conduit lifter in order to maximize the volume of flow therefrom. 
     Yet another object of the present invention is to provide a peristaltic pump which is sturdy and may be employed in rugged environments. 
     Another object of the present invention is to provide a peristaltic pump which is extremely durable at high speeds of operation. 
     Another object of the present invention is to provide a peristaltic pump that may be simply retrofitted with components to alter flow rate and pressure parameters of operation. 
     The invention possesses other objects and advantages especially as concerns particular characteristics and features thereof which will become apparent as the specification continues. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of the embodiment of the present invention with a portion of the lifter supports shown in section. 
     FIG. 2 is a sectional view showing the sequential operation of the peristaltic pump of FIG. 1 taken along line  2 — 2  of FIG.  1 . 
     FIG. 3 is a top plan schematic view of the flow pattern of the pump depicted in the prior figures. 
    
    
     For a better understanding of the invention reference is made to the following detailed description of the preferred embodiments thereof which should be taken in conjunction with the prior described drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Various aspects of the present invention will evolve from the following detailed description of the preferred embodiments which should be referenced to the hereinbefore delineated drawings. 
     The invention as a whole is depicted in the drawings by reference character  10 . The peristaltic pump  10  includes as one of its elements a fluid inlet  12  which may feed from a fluid reservoir (not shown). Fluid inlet  12  flows through a manifold  14  which essentially splits fluid inlet  12  into multiple streams. In the embodiment  10  depicted in FIGS. 1-3, fluid inlet  12  has been split into four separate streams,  16 ,  18 ,  20 , and  22 , shown schematically in FIG.  3 . FIG. 1 depicts fluid streams  16  and  22  most clearly. Directional arrows  24  illustrate the split of inlet stream  12 . Check valve means  26  insures the flow of fluid from inlet  12  from outlet  28  in one direction through the action of pump  10 . This operation will be described in greater detail hereinafter. Directional arrow  30  shows the flow of fluid from pump  10 , in this regard. Again, FIG. 3 depicts check valve means  26 , schematically, with respect to fluid stream  16 ,  18 ,  20 , and  22 . That is to say, check valves  32  and  34  are associated with fluid stream  16 , while check valves  36  and  38  are associated with fluid stream  22 . Similar check valves operate with respect to fluid streams  18  and  20 . Manifold  40  combines the flow from fluid stream  16 ,  18 ,  20 , and  22  into fluid outlet  28 . Eductor  29  may connect inlet  12  with outlet  28 , to allow a small portion of outlet fluid to travel back to the inlet stream. Eductor  29  permits pump  10  to run at high speeds, which will be discussed more fully hereinafter. 
     Each fluid stream,  16 ,  18 ,  20 , and  22  has an associated flexible conduit. Turning to FIG. 2, it may be observed that flexible conduits  42 ,  44 ,  46 , and  48  are associated with fluid streams  16 ,  18 ,  20 , and  22 , respectively. For the sake of clarity, FIG. 1 depicts flexible conduits  42  and  46  most clearly. Flexible conduits  42  and  46  are elongated and communicate with fluid inlet  12  as well as fluid outlet  28 . Thus, exemplary conduit  42  includes a fluid inlet portion  50  and a fluid outlet portion  52 . The same relationship exists with respect to flexible conduits  44 ,  46 , and  48 . Each conduit may range in size from 1 inch to 5 inches in diameter and be able to withstand pressure up to 2,500 psi. For example, conduits  42 ,  44 ,  46 , and  48  may take the form of industrial hoses composed of elastomeric material having multiple high tensile strength steel belts imbedded within the hose wall. 
     Compressing means  54  is utilized to sequentially press or collapse conduits  40 ,  42 ,  44 ,  46 , and  48 . It may be apparent from FIG. 1 that compressing means utilizes a motor  56  which may be operated electrically, through an internal combustion mechanism, by manual means, and the like. In any case, motor  56  rotates the output shaft  58 . Shaft  58  is held to journals  60  and  62  and maintained in this position by supports  64  and  66 . 
     Locked to shaft  58  are a pair of eccentric members  68  and  70 , which necessarily, rotate with shaft  58 . A plurality of bearings  72  and a plurality of bearings  74  are associated with first eccentric member  68  and second eccentric member  70 , respectively. Turning to FIG. 2, it may be seen that bearings  76  and  78  are employed to collapse or squeeze flexible conduit  42 . In such a case, compressing means  54  takes the form of a conduit or hose lifter  80  which is movable upwardly and downwardly according to directional arrow  82 , FIG. 2. A plurality of rollers  84  fixed to journals  60  and  62  allow lifter  80  to move up and down. It should be noted that a fixed plate  86  lies in opposition to conduit lifter  80  to effect the squeezing or collapsing of conduit  42 , best shown in FIGS. 1 and 2. Consequently, plate  88  and lifter  90  collapse conduit  44 , plate  92  and lifter  94  collapse conduit  46 , and plate  96  and lifter  98  collapse conduit  48 , in a sequential manner as shaft  58  turns. Although the actual mechanism for such squeezing or collapsing has been thoroughly discussed with respect to conduit  42  and it should be understood that a similar mechanism applies to the squeezing of the remaining conduits. Eductor  29  allows conduits  42 ,  44 ,  46 , and  48  to quickly expand with fluid and rebound from a collapsed state when pump  10  runs at elevated speeds. 
     Conduit lifter  80  is provided with a pair of protuberances or blocks  100  and  102  which contact the outer races of bearings  76  and  78 . Viewing again, FIG. 2, bearing  76  is shown in greater detail, in which outer race  104  rotates relative to inner race  106 . Plurality of ball bearings  108  lie in between outer race  104  and inner race  106 . Blocks  100  and  102  allow the use of lifter  80  against elongated portion of conduit  42 , which maximizes the flow of fluid therefrom. It should be further seen that bar  103  may be employed to connect lifters  80  and  94  together. It has been found that multiple bearing sets acting on individual lifters reduce friction, conserving energy, and prolong the life of the moving components of pump  10 . 
     In operation, with respect to conduit  42  and compressing means  54  associated therewith, motor  56  turns shaft  58  and eccentric member  68  locked thereto. Bearings  76  and  78  are moved upwardly, in FIG. 2, such that the outer races of such bearings, including outer race  104  of bearing  76 , contact block  100  and block  102  formed on conduit lifter  80 . When this occurs, lifter  80  squeezes conduit  42  against plate  86  such that fluid flows from conduit  42  according to directional arrow  30  through outlet  28 . The direction of such flow is due to check valve means  26 . As shaft  58  turns according to directional arrow  110 , lifter  80  retreats toward shaft  58  and lifter  90  begins to collapse or squeeze conduit  44 . At this point, conduit  46  is in its fully extended position between lifter  94  and plate  92 . However, when shaft  58  continues to turn, conduit  46  will be collapsed between lifter  94  and plate  92  to force liquid from conduit  46  through outlet  28 . The sequential collapsing of conduits  42 ,  44 ,  46 , and  48  produces a high volume steady flow of fluid through outlet  28 . Following collapse, each conduit  42 ,  44 ,  46 , and  48  quickly expand due to the elastomeric material and the high tensile strength steel embedded in the conduit wall. Eductor  29  also aids in this endeavor. Pump  10  may be easily retrofitted with hoses, lifters, bearings, and the like, to meet particular operation demands of flow rate and pressure. 
     While in the foregoing, embodiments of the present invention have been set forth in considerable detail for the purposes of making a complete disclosure of the invention, it may be apparent to those of skill in the art that numerous changes may be made in such detail without departing from the spirit and principles of the invention.