Pumps – Motor driven – Fluid motor
Reexamination Certificate
1997-10-27
2001-10-09
Tyler, Cheryl J (Department: 3746)
Pumps
Motor driven
Fluid motor
C417S533000, C417S538000
Reexamination Certificate
active
06299415
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to a double-acting pump of the kind which includes two cavities, each of which is divided into an operating chamber and a working chamber by means of a respective movable partition wall in the form of a piston or diaphragm, wherein each of the operating and working chambers is provided with a valve-controlled inlet and outlet for a gaseous driving and operating medium and for a pump-transported liquid working medium respectively, and wherein a device for transmitting movement of one partition wall to the other, and vice versa, extends between the movable partition walls.
DESCRIPTION OF THE RELATED ART
Double-acting pumps of this kind are known to the art from European Patent Specifications 0 132 913 and 0 181 756, for instance. The operating medium is normally air and the working medium one of the liquids that are pumped through pipes primarily in the food industry, the chemical process industry and the pharmaceutical industry. One drawback with known double-acting pumps is that they tend to generate undesirable pulsations in the transported working medium as a result of the particular conditions that prevail when the movement direction of the partition walls reverses.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a novel and advantageous double-acting pump with which the aforesaid drawback is at least substantially eliminated. It is also an object of the present invention to provide a pump of the aforesaid kind which has a long working life, is reliable in operation, incurs low operating costs, has low specific driving-medium consumption and small space requirements.
To this end, there is proposed in accordance with the present invention a double-acting pump of the aforesaid kind in which the movement transmission device is resilient or springlike in the movement transmission direction. As a result of this arrangement, an operating chamber will be evacuated when reversing the pump stroke direction essentially independently of the filling of the other operating chamber, wherein the energy which in known double-acting pumps is initially consumed in emptying said one chamber while generating pulsations and delaying the filling of said other chamber is now stored in the resilient transmission device without impeding filling of said other chamber. The energy or power stored in the transmission device is utilized during the continuation of the pump stroke to empty said one chamber, when the pressure in this chamber has been reduced. In this way, the occurrence of pulsations caused by changes in direction of the movement of the partition walls is essentially avoided and the pump will consume less energy. Further energy savings and smoothness in the transportation of the liquid working medium can be achieved by using flap valves in the valve-controlled working medium inlets and outlets.
The movement transmission device includes a rod which is journalled for axial movement in the movement transmission direction and which has at least one end connected to an associated partition wall through a spring element. The spring element may be connected to the associated partition wall through connecting means which enable the end of the spring element to be positioned obliquely in relation to the partition wall and the rod end respectively.
As a further embodiment, the rod can include a two-part rod which is journalled for axial movement in the movement transmission direction and whose mutually opposing ends are each connected to a respective partition wall. The rod parts are then mutually connected through the medium of a spring element.
In accordance with the invention, the working chambers may be located closest to one another, with the operating chambers located outwardly of an associated partition wall. Additionally, each of the working chambers is connected to a common working medium inlet chamber located between the working chambers, through the medium of a flap valve mounted in a respective chamber wall, and each of the working chambers is further connected to a common working medium outlet chamber located between the working chambers, through the medium of a flap valve mounted in a respective chamber wall.-before
REFERENCES:
patent: 1835919 (1931-12-01), Waseige
patent: 2526331 (1950-10-01), Copping
patent: 2877715 (1959-03-01), Rittenhouse
patent: 4008984 (1977-02-01), Scholle
patent: 4496294 (1985-01-01), Frikker
patent: 4521165 (1985-06-01), Handleman
patent: 5219274 (1993-06-01), Pawlowski et al.
patent: 0132913 (1985-02-01), None
patent: 763846 (1956-12-01), None
patent: 1435-814-A (1988-11-01), None
Jacobson & Holman PLLC
Tyler Cheryl J
LandOfFree
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