Flow rate accuracy of a fluidic delivery system
AssigneeCodman Neuro Sciences Sarl
InventorsRocco Crivelli, Alec Ginggen, Toralf Bork
Life of this patent
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Abstract
Improving the accuracy of the flow rate of a valve in a fluidic delivery device in which a desired flow rate may be achieved by varying the duty cycle of the valve. The flow rate of fluid delivery from the valve over its lifetime is stabilized by minimizing the voltage OPENING time of the valve to account for valve and piezoelectric actuator drift. Also, the valve OPENING time of one or more fluidic parameters that impact on the flow rate delivery by the valve and differ among fluidic delivery devices is compensated to optimize the flow rate accuracy.
Claims30
A method for optimizing, flow rate accuracy of a fluidic delivery system by compensating for at least one fluidic parameter effecting the flow rate accuracy of fluid dispensed by a valve, a block representing a predetermined duration of time over which the valve opens once and closes once, the valve being associated with a fluidic delivery device including a first fluidic delivery device processor and a first non-volatile memory device having stored therein at least one calibrated fluidic parameter determined for the fluidic delivery device, the fluidic delivery device being programmable by a control device having a control device processor, the method comprising the steps of:
- (a) calculating using the control device processor an Integer Compensated Valve OPENING Time Per Block and a Remainder Compensated Valve Opening Time Per Predetermined Time Interval based on the at least one calibrated fluidic parameter retrieved from the first non-volatile memory device;
- wherein the Integer Compensated Valve OPENING Time Per Block is determined as:
- Integer Compensated Valve OPENING Time Per Block=integer(Maximum Flow Rate Compensation Component+Valve OPENING Time Compensation Component+Valve CLOSING Time Compensation Component+Compliance Effect Compensation Component+Temperature-Pressure Relationship Compensation Component);
- (b) transmitting from the control device to the fluidic delivery device the calculated Integer Compensated Valve OPENING Time Per Block and the Remainder Compensated Valve Opening Time Per Predetermined Time Interval;
- (c) distributing the Remainder Compensated Valve OPENING Time Per Predetermined Time Interval as uniformly as possible to the blocks in the predetermined time interval;
- (d) determining for each block per predetermined time interval a Total Compensated Valve OPENING Time by adding the integer Compensated Valve OPENING Time Per Block and, if distributed to that particular block in the predetermined time interval, the uniformly as possible distributed Remainder Compensated Valve OPENING Time Per Predetermined Time Interval;
- and
- (e) Optimizing the flow rate accuracy of the fluidic delivery device by opening the valve based on the Total Compensated Valve OPENING time which has compensated for the fluidic parameters.
A fluidic delivery system with optimized flow rate accuracy by compensating for at least one fluidic parameter effecting the flow rate accuracy of fluid dispensed by a valve, a block representing a predetermined duration of time over which the valve opens once and closes once, comprising:
- a control device having a control device processor;
- and
- a fluidic delivery device including the valve, a first fluidic delivery device processor and a first non-volatile memory device for storing the flow rate and at least one calibrated fluidic parameter associated with the fluidic delivery device;
- the fluidic delivery device being programmed by the control device;
- the control device processor being programmed to:
- (a) calculate using the control device processor an Integer Compensated Valve OPENING Time Per Block and a Remainder Compensated Valve Opening Time Per Predetermined Time Interval based on the at least one calibrated fluidic parameter retrieved from the first non-volatile memory device;
- (b) transmit from the control device to the fluidic delivery device the calculated Integer Compensated Valve OPENING Time Per Block and the Remainder Compensated Valve Opening Time Per Predetermined Time Interval;
- wherein the programming of the first fluidic delivery device processor to calculate the Integer Compensated Valve OPENING Time Per Block is determined as:
- Integer Compensated Valve OPENING Time Per Block=Integer(Maximum Flow Rate Compensation Component+Valve OPENING Time Compensation Component+Valve CLOSING Time Compensation Component+Compliance Effect Compensation Component+Temperature-Pressure Relationship Compensation Component);
- the first fluidic delivery device processor being programmed to:
- (c) distribute the Remainder Compensated Valve OPENING Time Per Predetermined Time interval as uniformly as possible to the blocks in the predetermined time interval;
- (d) determine for each block per the predetermined time interval a Total Compensated Valve OPENING Time by adding the integer Compensated Valve OPENING Time Per Block and, if distributed to that particular block in the predetermined time interval, the uniformly as possible distributed Remainder Compensated Valve OPENING Time Per Predetermined Time Interval;
- and (e) optimize the flow rate accuracy of the fluidic delivery device by opening the valve based on the Total Compensated Valve OPENING time which has compensated for the fluidic parameters.
Dependencies are inferred from the claim text.