Triggering circuit for an aerosol drug-dispensing device

• US 7,357,133 B2
• Filed: 11/07/2001
• Issued: 04/15/2008
• Est. Priority Date: 11/13/2000
• Status: Expired due to Fees

• Current Assignee: The Technology Partnership PLC (TTP Group Ltd.)
• Original Assignee: The Technology Partnership PLC (TTP Group Ltd.)
• Inventors: Goodchild, Martin Scott
• Primary Examiner(s): DeMille; Danton D.
• Assistant Examiner(s): MATTER, KRISTEN CLARETTE
• Application Number:
  US10/416,307
• Publication Number:
  US 20040050382A1
• Time in Patent Office: 2,351 Days
• Field of Search: 128/200.14, 128/200.16, 128/203.12, 128/203.15, 128/203.21, 128/203.23, 732/041.5, 732/041.8, 738/618.5
• US Class Current: 128/200.14
• CPC Class Codes: A61M 11/005 using ultrasonics spraying or atomising liquids using ultrasonic vibrations in general B05B17/06
• CPC Class Codes: A61M 15/002 with air flow regulating means
• CPC Class Codes: A61M 15/0065 Inhalators with dosage or measuring devices A61M15/0028 takes precedence; dosage devices incorporated in aerosol cans B65D83/52
• CPC Class Codes: A61M 15/0085 using ultrasonics spraying or atomising liquids using ultrasonic vibrations in general B05B17/06
• CPC Class Codes: A61M 15/0086 Inhalation chambers
• CPC Class Codes: A61M 15/009 using medicine packages with incorporated spraying means, e.g. aerosol cans pocket atomiser of the injector type A61M11/08
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A61M 2205/073 Syringe, piston type
• CPC Class Codes: B05B 17/0638 spray being produced by discharging the liquid or other fluent material through a plate comprising a plurality of orifices
• CPC Class Codes: B05B 17/0646 Vibrating plates, i.e. plates being directly subjected to the vibrations, e.g. having a piezoelectric transducer attached thereto
• CPC Class Codes: G01P 13/006 by using thermal variables

Abstract

An electronic gas flow triggering circuit for use in an aerosol drug dispensing device has a voltage source and a self-nulling circuit to which voltage is supplied from the voltage source. A hot wire anemometer filament forms a component of the bridge circuit which is adapted to maintain a constant resistance of the anemometer filament, the bridge drive voltage being dependent upon the gas flow across the anemometer filament. A comparator compares the bridge output voltage with a reference voltage and provides a triggering signal to operate the device if the bridge drive voltage is greater than the reference voltage.

Claims

1. An electronic gas flow triggering circuit for use in an aerosol drug dispensing device, the circuit including:

a voltage source;

a self-nulling bridge circuit to which voltage is supplied from the voltage source;

a hot wire anemometer filament forming a component of the bridge circuit which is adapted to maintain a constant resistance of the anemometer filament, the bridge drive voltage being dependent upon the gas flow across the anemometer filament; and

a comparator for comparing the bridge drive voltage with a reference voltage such that a trigger signal is provided if a certain rate of change of gas flow is exceeded.

2. A triggering circuit according to claim 1, wherein the bridge circuit is a Wheatstone bridge.

3. A triggering circuit according to claim 1, wherein the reference voltage is derived from the bridge drive voltage, to prevent erroneous triggering due to changes in ambient temperature.

4. A triggering circuit according to claim 3, wherein the reference voltage is filtered to pass only low frequency signals. It is requested that multiple dependencies be removed from the application. If any multiple dependencies remain after amendment, said multiple dependencies should be deleted and the claim made dependent on the next previous claim.