Pumps – Motor driven – Fluid motor
Reexamination Certificate
2002-04-16
2004-01-13
Tyler, Cheryl J. (Department: 3746)
Pumps
Motor driven
Fluid motor
C417S502000, C417S505000, C417S503000, C417S400000, C417S401000, C222S253000, C222S129100, C222S136000, C222S250000
Reexamination Certificate
active
06676387
ABSTRACT:
RELATED U.S. APPLICATIONS
Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
REFERENCE TO MICROFICHE APPENDIX
Not applicable.
1. Field of the Invention
The present invention relates to a metering device.
2. Background of the Invention
Metering devices have been proposed before. One type of metering device is used to control the dispensing of a liquid or fluid, which may be supplied to the metering device under pressure, and the metering device acts to dispense a precisely predetermined quantity of the liquid or fluid. An alternative form of metering device monitors the flow rate of liquid or fluid passing through the device.
The present invention seeks to provide a metering device which may be used for either of the purposes outlined above.
It is to be noted that it has been proposed previously to use metering devices to control the relative metering of two or more reactive liquids which together form a two-component reactive system in ratio to each other prior to their being mixed and dispensed. Examples of such two-component reactive systems are epoxies, polyurethanes, acrylics, silicones and polysulphides with their typical functions as sealing, bonding, encapsulating, coating, mould making, moulding and electrical or thermal insulating. Needless to say, such materials are currently used in nearly every type of production circumstance and across a very broad range of industries.
Despite their current importance and level of application, it should be appreciated that the use of multi-component reactive liquid systems, despite all the advantages, is still the subject of considerable scepticism by designers and production engineers. This is for the simple reason that “state of the art”shot or flow metering, mixing and dispensing machinery does not assure that the correct relative proportioning of the two or more chemical components takes place within a tolerance, or even that it takes place at all. Mixed resin color changes, such as yellow and blue mixing to become green, can sometimes be used for visually checking that a degree of correct proportioning has taken place, but many premixed components are of approximately the same color and therefore no change is identifiable visually. Also, mixed product testing can be done on a random basis but if it is, it is not a check on the total product. Therefore, with the fact that “state of the art”machines can, and do, partially fail, fluctuate in failure, progressively fail through wear or totally fail, this is an area where the end mixed product specification is unqualified and where part or total failure of the end product remains a hazard. The scepticism of production engineers concerning this type of process is understandable, especially since quality assurance standards demand total control. Only sectors of the aircraft industry can presently justify a costly one hundred percent quality assurance system whereby part of a product batch is applied to a structure with its position in a structure being recorded while the other part of the batch is laboratory tested, rejected or approved, documented and stored.
While two or more component reactive systems have been mentioned, there are other areas of great significance where metering takes place such as with multiple chemical stream processes or in a single component metered shot application as, for instance, with grease being placed within a bearing. In all applications, the need remains to assure performance but in some applications the need is to ensure the avoidance of a catastrophe through product failure in the field.
EP 0,646,776A discloses a metering device for fluids which is specifically intended for use in a proportioning and mixing apparatus for a two-component material. The device is an oscillatory device.
In the arrangement disclosed in EP 0,646,776A, a housing is provided having a fluid inlet and a fluid outlet. A passage, within the housing, forms a communication between the fluid inlet and the fluid outlet. A rotary member is provided located within the passage which effectively seals the passage, the rotary member defining a diametrically extending bore which, in two rotational positions of the rotary member, becomes aligned with the passage. A ball is contained within the bore, and is adapted to form a sealing engagement with each of two seats provided for that purpose, at opposed ends of the bore.
In use of the metering device, shown in EP 0,646,776A, after the apparatus has been primed, so that the flow passage Within the housing and the bore within the rotary member are both full of liquid to be dispensed, when the rotary member is moved to a first position, with the ball engaging the seat located closest to the fluid inlet, fluid will flow through the fluid inlet and into the bore, pushing the ball away from the seat so that the ball moves axially of the bore until the ball engages the other seat. Fluid that was initially contained with the bore is thus expelled into the part of the passage adjacent the fluid outlet so that fluid is forced out of the metering device. When the ball engages the seat which is located adjacent the fluid outlet, no further fluid can flow through the device.
The rotatable element is then rotated through 180° so that the ball is again located at a position adjacent the fluid inlet. The cycle of operation then repeats. The rotatable element is rotated at such a rate that it is anticipated that the ball completes the journey from one seat to the other seat on every occasion that the rotatable element is in a position such that the bore is aligned with the passageway.
It is often difficult to maintain appropriate seals in the arrangement disclosed in EP 0,646,776A, bearing in mind that the ball is subjected permanently to the source of the fluid under pressure.
BRIEF SUMMARY OF THE INVENTION
The present invention seeks to provide an improved metering device.
According to this invention there is provided a metering device, the metering device comprising means defining a chamber having two opposed ends comprising an elongate bore, each end of the elongate bore accommodating a respective probe, the inner ends of which bound the chamber, at least one probe being axially adjustable in position, each probe having electrically conductive means extending from the inner end face of the probe, there being inlet means to enable fluid to enter one end of the chamber and inlet means to enable fluid to enter the other end of the chamber, there being outlet means to enable fluid to exit from said one end of the chamber, and outlet means to enable fluid to exit from the other end of the chamber, there being a shuttle provided within the chamber at a position intermediate said two ends, at least the opposed ends of the shuttle being electrically conductive, the shuttle acting sealingly to separate the two ends of the chamber, the shuttle being movable between two terminal positions, each probe being responsive to physical contact with the shuttle to generate a respective electrical signal when the shuttle reaches each one of said two terminal positions, there being valve means to control fluid flow which, in one condition, permit the entry of fluid into one end of the chamber and permit the simultaneous exit of fluid from the other end of the chamber and which, in another condition, permit the entry of the fluid into said other end of the chamber and permit simultaneous exit of fluid from the said one end of the chamber, there being control means adapted to change the condition of the valve means on receipt of a said electric signal generated when the shuttle reaches a said terminal position.
Advantageously the inlet and outlet means incorporate ports in the side-wall of the chamber and the inner-most end of each probe which defines the chamber is configured to permit the entry or exit of fluid if the inner-most end of the probe is aligned with a said port.
Conveniently the inner-most ends of the probes which defines the chamber are of reduced diameter.
Preferably the shuttle has a central part which is a sea
Sayor Emmanuel
Tyler Cheryl J.
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