Fluid handling – With leakage or drip collecting
Reexamination Certificate
2000-03-10
2001-06-05
Lee, Kevin (Department: 3753)
Fluid handling
With leakage or drip collecting
C137S398000
Reexamination Certificate
active
06240954
ABSTRACT:
TECHNICAL FIELD
The present invention relates to float controlled valve assemblies which include at least one valve means installed into a liquid flow in a pipeline or a pipeline armature, and a liquid receptacle that is fed with at least a part of a liquid flowing, through the valve means or escaping, as a result of a sealing failure, from a liquid supply system including said at least one valve means. The valve assembly further includes at least one balance float connected to a rotatable free end of a pivoted balance lever. The at least one balance float stays at a hither position above or with respect to the liquid level of the liquid in the receptacle while sad liquid level is below a pre-determined or permitted level, and the balance float stays at a lower position with respect to the liquid level of and immerses, at least partially, into the liquid contained in the receptacle when said liquid level reaches or exceeds said pre-determined or permitted level in the liquid receptacle. The valve means of the valve assembly comprises a flow passage determined by a valve seat that is arranged between a pressure chamber and an outlet chamber of the valve means. The valve means also comprises a piston-like- closure member having, a valve shaft and a piston head at one end of the valve shaft. The valve shaft is slideably guided between a first end position and a second end position. The closure member maintains a thoroughfare flow passage through the valve means in the first end position of the valve shaft, and the closure member closes the flow passage through the valve means when the valve shaft is moved to its other, second end position The piston head of the closure member is arranged within the pressure chamber of the valve means, and the valve assembly further includes a mechanism arranged between the balance lever and the valve shaft of the closure member of the valve means.
BACKGROUND ART
It is a common characteristic of most hitherto known float controlled valve assemblies used for monitoring and influencing the liquid level of receptacles that a flow passage of a valve means is altered by a displaceable closure member. The closure member is generally movable between two end positions associated with an open and a closed state of the valve means, respectively. Such known valve assemblies also have a definite mechanical linkage between the float and the closure member of the valve means which is moved, at least in certain phases of the changes in the liquid level of the receptacle, by the float. A known valve assembly of the kind indicated is described for example in U.S. Pat. No. 5,072,751, where a float is secured to the end of a longer arm of a single-arm lever capable of tilting around a fulcrum secured to a valve housing, and the closure member of the valve is assigned to the end of a shorter arm of the single-arm lever in a way that an upper end of the closure member is permanently pressed by the pressure of water flowing across the valve against the lever while said lever is driven between its two end positions by the float in both directions. As a result of this, during filling up or refilling the receptacle after discharge, the movement of the closure member in the closing direction of the valve slows down gradually and proportionally to the gradually slowing rate of the rise of the float. Thus, the time period needed for filling or refilling the receptacle is extremely long, and the closure member of the valve narrowing the flow passage of the valve gradually over such long periods of time, as well as the co-acting valve seat are subject to rapid wear. This is an inherent and major disadvantage of the type of known valve assemblies referred to and dealt with e.g. in U.S. Pat. No. 5,072,751.
Patent specifications EP-A-768487, EP-A-709607, U.S. Pat. No. 5,230,361, FR-A-1223714 and GB-A-2067271 disclose float controlled valve assemblies in which a spring mechanism between a pivoted balance lever and a closure member of a valve means provides for self-locked states of the balance lever and thus, said closure member of the valve means in both a first and a second end position of said closure member corresponding to a closed and a thoroughfare state of the valve, respectively. In addition to this, the mechanism has a snap-action function in both directions of movement between said first and second end position for quick opening/closing of the valve. In these known prior art approaches however, for initiating the snap-action of the mechanism in both directions, the respective self-locked states of its end positions must be overcome by exerting a definite torque load, acting on the balance lever in the one sense of rotation in the first end position and acting on said balance lever again, in the opposite sense of rotation in the second end position of the closure member of the valve. Consequently, the balance float(s) of the valve assembly must be connected-to the balance lever of the valve via a rigid linking member e.g. a rod which must be capable of bearing and transmitting both, tensile and compressing load. This characteristic feature of the known valve assemblies of self-locking and snap-action function involves the disadvantage that due to the necessity of maintaining a rigid linkage between the balance float(s) and the balance lever of the assembly, the valve means cannot be located at any remote or distant location from the receptacle, it must rather be arranged within or at least in the nearest proximity of the liquid receptacle. Thus, with the known valve assemblies cited and listed further above, a “remote control” of the liquid level of receptacles can not be performed without using known additional means of signal and/or power transmission.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a float controlled valve assembly, in which the rate of the closing and opening displacement of a closure member of the valve is not subject in any of the two directions, to the rate of the movement of the float, and which is, by appropriate dimensioning, suitable for both, the float controlled closing and re-opening of the valve.
Another objective of the present invention is the provision of a float controlled valve assembly, which enables the actuation of valves of large flow passages, even of valves of industrial sizes, by at least one relatively low weight float, whereby the valve assembly can also be used in industrial applications for automatically controlling the liquid level in all kinds of receptacles.
A yet another object of the present invention is to provide a valve assembly which also allows for a float controlled operation of valves that are located distantly from the liquid receptacle and thus, from the float associated therewith.
Finally, a further object of the invention lies in the provision of a float controlled valve assembly suitable for monitoring liquid, especially water supply systems of rooms, buildings, industrial plants and workshops, and for automatically closing the liquid, especially water supply when a leakage of the liquid or flooding resulting from pipe breakage or another sealing failure is detected.
In accordance with the above and other objects, the valve assembly of the present invention and having the characteristic features listed and described in the introductory part of the present description is characterised by a novel mechanism that is designed so as to having and staying in an at least approximately self-locked state when the valve shaft of the closure member of the valve means of the valve assembly stays in its first end position, the at least approximately self-locked state of the mechanism being substantially resistant to forces exerted onto and biassing the valve shaft towards its second end position in the sense of closing the thoroughfare flow passage through the valve means but the at least approximately self-locked state of the mechanism being, in accordance with the spirit of the invention, released when said at least one balance float loosing, at least partially, its weight by immersing, at l
Lee Kevin
Wood Herron & Evans L.L.P.
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