Method of compensating for changes in flow characteristics of a dispensed fluid
US5920829A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 31, 1997 |
| Grant date | Jul 6, 1999 |
| Priority date | — |
| Expiry date | Oct 31, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05D7/0623
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A fluid dispensing control for controlling the dispensing of a fluid by a metering valve through a nozzle onto a workpiece. An initial value of a flow characteristic of the fluid is determined that is correlated to the relationship between the flow rate of the fluid and nozzle pressure. Desired nozzle pressure values are periodically determined by evaluating a model of flow rate of the fluid through nozzle in response to the initial value of the flow characteristic and a desired flow rate value. Thereafter, the control provides command signals to the metering valve as a function of the desired nozzle pressures. A new value of the flow characteristic is determined as a function of the measured volume of fluid dispensed during the dispensing cycle to the measured nozzle pressure. During a subsequent dispensing cycle, the control determines the desired nozzle pressures by evaluating the model of flow rate of the fluid through the nozzle as a function of the new value of the flow characteristic. The process of reevaluating the flow characteristic over successive dispensing cycles as a function of measured volumes of fluid dispensed and measured nozzle pressures, and using those updated…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.