Pumps – Expansible chamber type – Inlet and discharge distributors at opposite ends of tubular...
Reexamination Certificate
1999-02-16
2001-07-31
Walberg, Teresa (Department: 3742)
Pumps
Expansible chamber type
Inlet and discharge distributors at opposite ends of tubular...
Reexamination Certificate
active
06267570
ABSTRACT:
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.
REFERENCES:
patent: 4365943 (1982-12-01), Durrum
patent: 5033943 (1991-07-01), Durrum et al.
patent: 5064358 (1991-11-01), Calari
patent: 5620313 (1997-04-01), Fockenberg
patent: 1910436 (1970-09-01), None
Bielen, Jr. Theodore J.
Patel Vinod D.
Walberg Teresa
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