Pumps – Expansible chamber type – Electrically or magnetically actuated distributor
Patent
1998-12-16
2000-10-17
Yuen, Henry C.
Pumps
Expansible chamber type
Electrically or magnetically actuated distributor
417514, F04B 4900, F04B 700
Patent
active
061321885
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a metering pump designed in particular for fitting to a machine for measuring out liquids.
BACKGROUND OF THE INVENTION
Metering pumps are known that comprise a pump body defining a cylindrical pump chamber having an admission orifice and a delivery orifice situated at opposite ends of the chamber. A piston associated with a drive rod is mounted inside the pump chamber to slide with reciprocating motion between the admission orifice and the delivery orifice. The piston has a pump orifice passing therethrough, which orifice is alternately opened and closed by a non-return valve.
With pumps of that kind, the fluid to be packaged comes into contact with both faces of the piston, thereby solving some of the liquid contamination problems that arise with conventional positive displacement pumps in which the liquid to be metered out comes into contact with one side only of the piston (the admission and delivery orifices of the pump chamber then both being situated at the same end of the chamber).
However, in existing pumps, the drive rod passes through the wall of the pump body, thus making it necessary to provide sealing between said wall and the drive rod. This sealing gives rise to difficult problems, particularly when the fluid to be packaged is abrasive or chemically aggressive, since the reciprocating motion of the drive rod runs the risk of damaging the gaskets quickly. Major problems also arise when fluids need to be packaged in sterile manner because of the pollution that might be conveyed by the drive rod in its reciprocating motion: it is then necessary to provide complex devices making use of sterile fluid or vapor barriers, or indeed membranes which are fragile.
OBJECTS AND SUMMARY OF THE INVENTION
The invention provides a metering pump comprising a pump body defining a cylindrical pump chamber having a longitudinal axis and presenting an admission orifice and a delivery orifice situated at opposite ends thereof, a piston having a pump orifice passing therethrough and mounted inside the pump chamber to slide in reciprocating motion between the admission orifice and the delivery orifice, a drive rod for driving the piston, a valve mounted to move relative to the piston between a position in which it opens the pump orifice and a position in which it closes it, and a sleeve of non-magnetic material mounted stationary inside the pump body parallel to the longitudinal axis of the pump chamber and possessing a closed end situated inside the pump body and an open end opening to the outside of the pump body, the drive rod being fitted with a magnetic element acting through the sleeve to co-operate with a magnetic cage surrounding the sleeve and coupled to the piston.
In this way, the drive rod which moves inside the sleeve is completely isolated by the sleeve from the flow inside the pump chamber. Sealing is provided only between the sleeve and the pump body which are fixed relative to each other. There is thus no risk of leakage or contamination of the above-mentioned fluid.
According to other advantageous characteristics of the invention: the sleeve with a second magnetic cage surrounding the sleeve and secured to the valve; and the second magnetic element is disposed to urge the valve constantly towards its closed position. The field generated between the second magnetic element and the second magnetic ring thus provides magnetic return for the valve. Unlike the resilient return force exerted by a spring, the magnetic force field decreases on opening and increases on closing, thereby improving the operation of the non-return valve.
In a variant embodiment, the valve and the second magnetic cage are mounted to pivot relative to the sleeve.
In an advantageous embodiment, the magnetic cage comprises at least two rings surrounding the sleeve and interconnected by a link member extending parallel to the sleeve, the magnetic element generating a magnetic field parallel to the axial direction of the sleeve and possessing two ends having the rings of the magnetic cage placed
REFERENCES:
patent: 2686280 (1954-08-01), Strong et al.
patent: 3532446 (1970-10-01), Herreshoff
patent: 3899703 (1975-08-01), Kinnison
patent: 4080112 (1978-03-01), Zimmermann
patent: 4231722 (1980-11-01), Teichmann
patent: 4465439 (1984-08-01), Seino
Gimie Mahmoud M
Serac Group
Yuen Henry C.
LandOfFree
Dosing pump with magnetic control does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Dosing pump with magnetic control, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dosing pump with magnetic control will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-462546