Patent for Dynamically Adjustable Reciprocating Fluid Dispenser

by | Metering Pumps, Patents, Zaxis Inc

Electronic Variable Metering Pump (eVmP)

The patented eVmP system is a precision metering and fluid dispenser combined with a detachable Touch Screen Interface (TSi) for simple programing and immediate teach and control. This pump technology combines precision ceramic pump components and an electronically controlled linear stepper actuator to make ultra-fine adjustments to angle position, thereby changing the volume of metered liquid. This allows the eVmP system to provide dynamic fluid displacement to overcome variations in viscosity and surface tension. The eVmP is the latest in fluid metering and dispense technology.

Summary of the Invention

The present invention relates to accurately and repeatably dispensing fluid. In particular, the present invention relates to systems and methods for providing a dynamically adjustable, synchronously and/or asynchronously reciprocating fluid dispenser. 

Implementation of the present invention takes place in association with a reciprocating fluid pump. A pump drive motor is coupled to the reciprocating fluid pump to actuate a pump shaft within a pump cylinder, wherein the pump shaft includes a cut out portion (duct) that allows fluid to selectively pass thereby within the pump cylinder. As the pump shaft rotates within the pump cylinder, fluid is allowed to enter into a pump bore defined by a portion of the pump cylinder through a pump ingress port. As the pump shaft rotates, it blocks the pump ingress port. Further rotation allows the duct to allow the fluid in the pump bore to be dispensed through a pump egress port. This process may be repeated for subsequently dispensing volumes of fluid using the reciprocating fluid pump. 

Implementation of the present invention further includes an adjustment motor (e.g., a linear actuator, etc.) that is coupled to an adjustment mechanism, which selectively adjusts the volume of the pump bore. In at least one implementation, the volume of the pump bore is adjusted as the angle of the pump shaft is modified. A modification of the angle changes the stroke of the pump shaft. In another implementation, the volume of the pump bore is adjusted through a system of gears to selectively change the stroke of the pump shaft. Further, at least some implementations allow for synchronous and/or asynchronous reciprocation. 

Further implementation includes a controller coupled to the adjustment motor to dynamically control the adjustment motor to cause the adjustment mechanism to be precisely and repeatably modified. As such, the volume of fluid dispensed is extremely accurate, repeatable, and dynamic. Moreover, a controller may be used to provide control over the particular waveform of a synchronously and/or asynchronously reciprocating fluid dispenser. 

As the methods and processes of the present invention have proven to be useful in the area of dynamically dispensing fluid, those skilled in the art can appreciate that the methods and processes can be used in a variety of different applications, in a variety of different areas of manufacture to yield, and embrace a variety of different kinds of fluids. Examples of such industries include the medical industry, the industrial industry, the electronics industry, the food industry, the dairy industry, the precision cleaning industry, the cosmetic industry, the hygene industry, etc. Examples of such fluids include adhesives, lubricants, chemicals, drugs, paints, pigments, resins, solvents, epoxies, inks, ceramic slurries, solutions, candy coatings, polishes, flavorings, food preservations, cleaning agents, pigments, fragrances, gases, liquids, ets. 

These and other features and advantages of the present invention will be set forth or will become more fully apparent in the description that follows and in the appended claims. The features and advantages may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. Furthermore, the features and advantages of the invention may be learned by the practice of the invention or will be obvious from the description, as set forth hereinafter. 

Background of the Invention

The present invention relates to accurately and repeatably dispensing fluid. In particular, the present invention relates to systems and methods for providing a dynamically adjustable, synchronously and/or asynchronously reciprocating fluid dispenser. 

A variety of industries require a safe, accurate handling of fluid. One such industry is the medical industry. By way of example, in the medical industry an assay testing procedure is typically employed to determine whether an infectious disease (e.g., hepatitis or another infectious disease) is present in a particular blood serum. As part of the testing procedure, a biological sample is disposed into a testing receptacle. A reagent is added to the biological sample. In performing the test, it is important that the amount of the biological sample and the amount of the reagent are accurate. In particular, the amount of the reagent added to the biological sample may be in the range of 50 .mu.L-100 .mu.L, with a required accuracy of .+-.0.5 .mu.L. 

The assay testing procedure may further include a variety of separate test receptacles to perform a variety of assay tests to confirm and/or compare results. Some assay testing procedures may include disposing a series of specific reagents. 

Valveless, positive displacement pumps have been used in applications that require a safe, accurate handling of fluid. An example of a valveless, positive displacement pump is disclosed in U.S. Pat. No. 4,008,003. While the pump disclosed in U.S. Pat. No. 4,008,003 is an available technique, the pump does not provide an accurate calibration for metering and dispensing fluids. For example, the piston stroke of the pump is not easily adjusted and the angular displacement of the ports cannot be readily calibrated. 

Further problems with techniques used in industries that require a safe, accurate handling of fluid include the fact that complex pump designs increase the likelihood for error in manufacturing and assembling the pumps. And, pump designs with moving parts contribute to field failure and maintenance costs. 

Thus, while techniques currently exist that are used in industries requiring a safe, accurate handling of fluid, challenges still exist with such techniques, including a requirement for calibration of the fluid-handling device for each surrounding condition, an inability to provide accurate calibration, an increased likelihood for error, an increased likelihood for field failure, increased maintenance costs, and other such challenges. Accordingly, it would be an improvement in the art to augment or even replace current techniques with other techniques. 

United State Patent
Granted May 4, 2010 to
Zaxis, Inc.

-Assignee-
Patent No. US7,708,535 b2

Systems and methods for providing a dynamically adjustable reciprocating fluid dispenser