Precision Fluid Dispensing Using Peristaltic Roller Control

Abstract

A precision fluid dispensing system that can be effectively used for accurate fluid dispensing in peristaltic pumps if roller control is used. A peristaltic pump driven by a primary motor with a first encoder can be combined with pinch valves allowing a dispense tube to be open while a source tube is blocked. Controlled roller movement is used to move the next roller to the same starting position as the previous roller was on the previous dispense, the dispense pinch valve is closed and the source valve is opened. The system uses roller positioning where the each roller is properly positioned so that each dispense cycle starts in the same position. The precision and accuracy is better than 0.3% total. Tubing can be pre-stretched using a second motor and second encoder. Tube wear and stretch during use can be monitored by the second encoder.

Description

[0001]This application is a continuation-in-part of application Ser. No. 14 / 685,161 filed Apr. 13, 2015 which claimed priority from, U.S. Provisional Patent Application No. 61 / 978,911 filed Apr. 13, 2014. Application Ser. No. 14 / 685,161 and 61 / 978,911 are hereby incorporated by reference in their entirety.BACKGROUNDField of the Invention[0002]The present invention relates to peristaltic pumps and more particularly to a precision fluid dispensing using peristaltic roller control.Description of the Prior Art[0003]Peristaltic pumps find use for fluid dispensing in many fields where pump contamination is a concern, aggressive fluids can be used, slurries that can pass through the peristaltic pump or minimizing shear in shear sensitive fluids. A peristaltic pump mostly uses rollers to squeeze, occlude, flexible tubing against a pressure shoe forcing fluid to move between rollers. It is generally assumed in the art that it is very difficult to achieve accurate, repeatable precision dispen...

AI Technical Summary

Benefits of technology

The present invention is about a peristaltic system that can accurately dispense fluids using roller control. This system can be combined with pinch valves to open a dispense tube while blocking a source tube. When the roller movement is used to move the next roller to the same starting position, the dispense pinch valve is closed and the source valve is opened. Drip retention is used to move the fluid back from the dispensing tips so that the valve actuation safely moves the fluid in the tube. The technical effect of this invention is to provide a reliable and efficient fluid dispensing system that prevents clogging and minimizes fluid waste.

Problems solved by technology

It is generally assumed in the art that it is very difficult to achieve accurate, repeatable precision dispensing with this type of pump due to roller progression, We have found that this is true except where each cycle can be repeated with the rollers in the same place for the start of a dispense.

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