Method and apparatus for accurately dispensing liquids and solids

• US 6,286,566 B1
• Filed: 10/03/2000
• Issued: 09/11/2001
• Est. Priority Date: 11/20/1996
• Status: Expired due to Term

• Current Assignee: Fluid Research Corporation
• Original Assignee: Fluid Research Corporation
• Inventors: Smith, Steven, Clark, Timothy S., Cline, David J.
• Primary Examiner(s): Douglas, Steven O.
• Application Number:
  US09/677,932
• Time in Patent Office: 343 Days
• Field of Search: 141/1, 141/2, 141/18, 141/83, 141/98, 222/63, 222/145.6, 222/459, 222/504, 222/1, 251/335.3
• US Class Current: 141/83
• CPC Class Codes: B01F 25/43141 composed of consecutive sections of helical formed elements
• CPC Class Codes: B01F 35/71775 using helical screws
• CPC Class Codes: B05C 11/1005 responsive to condition of liquid or other fluent material already applied to the surface, e.g. coating thickness, weight or pattern
• CPC Class Codes: B05C 5/0225 characterised by flow controlling means, e.g. valves, located proximate the outlet B05C5/0258, B05C5/0275 take precedence; supply valves upstream the coating head B05C11/1036
• CPC Class Codes: B29B 7/726 Measuring properties of mixture, e.g. temperature or density B29B7/724 takes precedence
• CPC Class Codes: B29B 7/728 Measuring data of the driving system, e.g. torque, speed, power, vibration B29B7/724 takes precedence
• CPC Class Codes: B29B 7/748 Plants B29B7/7433, B29B7/7485, B29B7/7495 take precedence
• CPC Class Codes: F04C 13/001 Pumps for particular liquids
• CPC Class Codes: F04C 13/002 for homogeneous viscous liquids
• CPC Class Codes: F04C 14/06 specially adapted for stopping, starting, idling or no-load operation
• CPC Class Codes: F04C 14/08 characterised by varying the rotational speed
• CPC Class Codes: F04C 2/1073 where one member is stationary while the other member rotates and orbits
• CPC Class Codes: F04C 2210/24 mixed, e.g. two-phase fluid
• CPC Class Codes: F04C 2210/44 Viscosity
• CPC Class Codes: F04C 2220/24 for metering throughflow
• CPC Class Codes: F04C 2270/00 Control; Monitoring or safety arrangements

Abstract

A system for metering and dispensing single and plural component liquids and solids as described herein. The dispensing system has a microprocessor-based control system and volumetrically efficient non-reciprocating pumps which provide a very accurate control of component ratios, shot sizes, flow rates and dispense durations. The dispensing system maintains constant pressure between the output of the pump and the dispense head. The progressive cavity pump is formed from individual, interlocking pressure sections, each of which has a double helix bore. A rotor is inserted into the double helix bore with an interference fit. The dispense head has no dynamic fluid sealing surfaces and instead uses bellows as a sealing mechanism. The dispensing system includes a simple, easy to use calibration procedure and a weight scale. The system also has numerous feedback components for accurately controlling the pressure, flow rates, fluid levels and amounts of fluids dispensed

Claims

1. A method of calibrating a dispensing system having a pump motor and an output nozzle, the method comprising the steps of:

1) requesting the dispensing system to dispense a certain amount of fluid;

2) placing a container under the output nozzle;

3) initiating the dispensing system to dispense the fluid into the container;

4) monitoring the rotation of the pump motor during the dispense cycle;

5) determining the expected amount of fluid dispensed based upon the monitored rotation of the pump motor during the dispense cycle;

6) weighing the fluid dispensed into the container;

7) comparing the expected weight of the fluid dispensed with the actual weight dispensed;

8) deriving the amount of rotation of the pump motor per unit measure of fluid dispensed.

2. A method of calibrating a multi-channel dispensing system having output nozzles, the method comprising the steps of:

1) requesting the dispensing system to dispense a certain amount of fluid;

2) placing a container under the output nozzle;

3) initiating the dispensing system to dispense the fluid into the container;

4) monitoring the amount of rotation of the pump motor during the dispense cycle;

5) using the monitored amount of rotation to determine the expected amount of fluid dispensed;

6) weighing the fluid dispensed into the container;

7) comparing the expected weight of the fluid dispensed with the actual weight dispensed;

8) deriving the proper amount of rotation of the pump motor per unit measure of fluid dispensed;

9) repeating steps (1)-(8) for each channel of the dispensing system.