Fluid handling – Systems – With flow control means for branched passages
Reexamination Certificate
2000-04-19
2001-04-24
Fox, John (Department: 3753)
Fluid handling
Systems
With flow control means for branched passages
C137S329050
Reexamination Certificate
active
06220299
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a multi-way valve for a fluid, such as a liquid or gas.
BACKGROUND OF THE INVENTION
A prior art valve is disclosed in U.S. Pat. No. 4,431,019; and European Patent Nos. 0,578,168 and 0,085,298.
The valve according to the present invention is particularly intended to be used in a dialysis machine which, in its liquid-preparation stage, comprises a plurality of valves of this type. These valves are usually solenoid-operated. The valve can be of the one-way or two-way type or any multi-way type of valve.
These types of valves are provided with a diaphragm which abuts a valve seat in the valve. Wear arises during operation of the valve and abutment of the diaphragm against the valve seats. The function of the valve deteriorates and after a certain period of time leakage arises. In order to ensure reliable operation of these valves, the diaphragm is thus exchanged once a year. This implies that a service engineer travels out to the machine and disassembles the machine and all of the valves to exchange the diaphragms. The costs for this service are therefore high, and particularly the labor costs.
It has been proposed to arrange the diaphragm in some form of cassette which would be simpler to exchange to thereby reduce the precautionary service time.
One object of the present invention is thus to provide an arrangement in a valve which permits simplified procedures during such precautionary services.
A further object of the present invention is to suggest a construction which implies that the diaphragm does not need to be exchanged, whereby the service costs can be radically reduced.
The present invention thus relates to a valve comprising at least one inlet and at least one outlet for a fluid such as a liquid or gas. The inlet and/or the outlet are provided with a valve seat for cooperation with a diaphragm. An operating arrangement causes the diaphragm to abut the valve seat for selective operation of the valve.
SUMMARY OF THE INVENTION
In accordance with the present invention, these and other objects have now been realized by the invention of a valve comprising a housing including at least one fluid inlet, and at least one fluid outlet, a valve seat for at least one of the fluid inlet and the fluid outlet, the valve seat having a predetermined size, a diaphragm movable between a first position engaged with the valve seat and a second position disengaged from the valve seat, the diaphragm having a predetermined surface area which is greater than the predetermined size of the valve seat whereby the predetermined surface area of the diaphragm is greater than a surface area necessary for abutment against the valve seat, an actuator for selectively actuating the diaphragm between the first and second positions, and an activator for displacing the diaphragm whereby an at least partially unused portion of the predetermined surface area of the diaphragm is exposed to the valve seat upon the displacement of the diaphragm. Preferably, the fluid comprises a liquid or a gas.
In accordance with one embodiment of the valve of the present invention, the diaphragm is circular and has a center, and the activator is adapted to rotate the diaphragm about the center. Preferably, the activator is adapted to rotate the diaphragm through an angle of between about 10 and 45°, and preferably to an angle of about 18°.
In accordance with another embodiment of the valve of the present invention, the activator is adapted to linearly displace the diaphragm in a direction substantially perpendicular to the valve seat.
In accordance with another embodiment of the valve of the present invention, the activator is adapted to displace the diaphragm stepwise by an amount whereby a completely unused portion of the predetermined surface area of the diaphragm is exposed to the valve seat upon the displacement.
In accordance with another embodiment of the valve of the present invention, the activator includes locking means for preventing reintroduction of a previously exposed portion of the predetermined surface area of the diaphragm to exposure to the valve seat upon the displacement.
In accordance with another embodiment of the valve of the present invention, the housing includes a pair of fluid outlets, and including a valve seat for each of the pair of fluid outlets.
In accordance with another embodiment of the valve of the present invention, the valve includes a power source for operating the activator. Preferably, the power source comprises a solenoid or motor.
According to the present invention, the diaphragm has a dimension which is greater than that which is necessary for abutment against the valve seat. Furthermore, an activation arrangement is provided for displacement of the diaphragm so that a new, at least partially unused, region of the diaphragm is exposed to the valve seat.
Preferably, the diaphragm is circular, whereby the activation arrangement rotates the diaphragm about its center so that a new sector is exposed to the valve seat. The rotation can take place through an angle of about 10°-45°, particularly 18°, depending on the desired operating life.
Alternatively, the diaphragm can be displaced linearly and substantially perpendicular to the valve seat.
The diaphragm can be displaced in steps by an amount such that a completely new portion of the diaphragm is exposed to the valve seat.
Alternatively, displacement can take place substantially continuously or in small steps so that the diaphragm is continuously, or substantially continuously, renewed.
Preferably, a locking arrangement is provided which prevents return of a previously exposed portion of the diaphragm to exposure to the valve seat.
The valve is preferably a two-way valve which comprises an inlet and two outlets, these being aligned with each other and whereby each outlet has a valve seat.
The activation arrangement can be powered by a power source such as a solenoid or motor. In this manner, there is no longer any need to dismantle the machine; instead “exchange” of the diaphragm can be initiated electrically, for example by pressing a button or via a micro-computer which may be remote controlled.
REFERENCES:
patent: 998543 (1911-07-01), Meyer
patent: 1618119 (1927-02-01), Walling
patent: 3296026 (1967-01-01), Long
patent: 4431019 (1984-02-01), Kopp et al.
patent: 5653422 (1997-08-01), Pieloth et al.
patent: 1 425 632 (1968-11-01), None
patent: 0 085 298 B1 (1986-06-01), None
patent: 0 578 168 A1 (1993-07-01), None
patent: 180 779 (1962-09-01), None
Arvidsson Lars
Brunk Nina
Jonsson Jorgen
Lennerstedt Malte
Malm Ingmar
Fox John
Gambro Lundia AB
Lerner David Littenberg Krumholz & Mentlik LLP
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