US 2003/0196660 A1 · Vibrating element liquid discharging apparatus having gas pressure sensing

Abstract

A nebulizer determines the pressure and flow direction of the receiving gas for atomized liquid. A member of the apparatus is subjected to pressure exerted by the gas. The member is coupled to a bi-directional mechanical-electrical conversion element, such as a piezoelectric element, to form a pressure transducer. The member exerts a mechanical loading on the element responsive to the gas pressure to which it is subjected. In one embodiment, the element mechanically vibrates responsive to alternating electrical energization to discharge the liquid into the gas. The electrical admittance of the element is alterable by the mechanical loading applied to the element by the member. The difference between admittances measured in the loaded condition of the element and in an unloaded condition at the selected energization frequency is an indication of the pressure of the gas. By observing whether the magnitude of the admittance in the loaded state is greater or less than that in the unloaded state, the flow direction of the gas may also be determined. Or the flow direction may be determined by observing the changes in admittance as the frequency of the electrical energization is varied. In another embodiment, the piezoelectric element is not energized. The electrical output of the element, when subjected to a mechanical loading from the gas pressure, is used to detect gas pressures and/or as an indication of the gas pressure.

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Claims87

Dependent claims

A method for use with a discharging means discharging a fluid substance into a receiving gas, said method determining the pressure of the receiving gas, said method comprising the steps of:

(a) placing the discharging means in fluid communication with the receiving gas so that a bidirectional mechanical-electrical conversion element is subjected to mechanical loading responsive to the gas pressure of the receiving gas, the element mechanically vibrating responsive to the application of alternating electrical energization to the element, the element having an admittance, the admittance of the element at a given frequency of alternating electrical energization being alterable by a mechanical loading of the element;
(b) applying alternating electrical energization to the element at a selected frequency;
(c) subjecting the element to mechanical loading responsive to the pressure of the receiving gas;
(d) measuring the admittance exhibited by the element in the loaded condition when energized by the electrical energization of the selected frequency;
and
(e) determining the difference between the admittance measured in step (d) and another value as an indication of the pressure of the receiving gas.

3 more elements

A method for use with a discharging means discharging a fluid substance into a receiving gas, said method determining the flow direction of the receiving gas, said method comprising the steps of:

(a) placing the discharging means in fluid communication with the receiving gas so that a bidirectional mechanical-electrical conversion element is subjected to mechanical loading responsive to the gas pressure of the receiving gas, the element mechanically vibrating responsive to the application of alternating electrical energization to the element, the element having an admittance, the admittance of the element at a given frequency of alternating electrical energization being alterable by a mechanical loading of the element opposite directions of flow of the receiving gas subjecting the member to differing pressures and exerting differing mechanical loading on the element;
(b) applying alternating electrical energization to the element at a selected frequency other than the resonance frequency of the pressure transducer;
(c) measuring the admittance exhibited by the element in an unloaded condition when energized by the electrical energization of the selected frequency;
(d) subjecting the element to mechanical loading responsive to the pressure of the receiving gas;
(e) measuring the admittance exhibited by the element in the loaded condition when energized by the electrical energization of the selected frequency;
(f) comparing the admittance obtained in step (c) with the admittance obtained in step (e) to determine the relative magnitude of the measured admittances;
and
(g) determining from the relative magnitudes of the measured admittances, the direction of flow of the receiving gas.

5 more elements

Dependencies are inferred from the claim text.

Description13,077 words

Summary1,777 words

#The present invention relates to an improved apparatus, such as a nebulizer apparatus, for discharging fluids, and to a method of operating same. Nebulizers, or atomizers, are devices that generate a fine spray or aerosol, usually of a liquid. A particularly useful application for nebulizers is to provide a fine spray containing a dissolved or suspended particulate or colloidal pharmaceutical agent for administration to a subject by inhalation. Such inhalation treatment is highly effective for conditions affecting the subject's respiratory organs. Further, since the lungs are close to the heart and the circulatory system of the body, drug administration by inhalation provides an effective and rapid delivery system for a drug to all organs of the body. In other applications, nebulizers provide a fine spray of water for humidification.

#When used to dispense a pharmaceutical agent to a subject, a nebulizer in the form of an inhaler may be placed directly in the mouth or nose of the subject so that the spray can be entrained in the respiratory gases which are inhaled during normal, spontaneous breathing of the subject.

#In other applications, the subject breathes with the aid of a respiratory ventilator. A typical ventilator has a breathing circuit comprising an inhalation limb and an exhalation limb connected to two arms of a Y-connector. The third arm of the Y-connector is connected, via a patient limb, to a mouthpiece, mask, or endotracheal tube for the subject. The ventilator provides a complete or partial supply of breathing gas to the subject through the inhalation limb during inhalation. The contraction of the subject's lungs discharges gases through the exhalation limb during exhalation. When a nebulizer is employed in conjunction with a ventilator, it is typically placed in the patient limb to discharge into the breathing gases inhaled by the subject but it can also be placed in the inhalation limb of the breathing circuit.

Brief description of the drawings18 figures

#The present invention will be further understood by reference to the following detailed description and accompanying drawings, in which

#FIG. 1 is a somewhat schematic, cross-sectional view of a fluid discharging apparatus of the present invention in the form of a nebulizer connected to a breathing circuit which, in turn, is connected to a ventilator;

#FIG. 2 is an exploded, cross-sectional view of the apparatus of FIG. 1;

Detailed description10,870 words

#In the drawing figures, in which like reference numerals designate like parts throughout the disclosure, a fluid discharging and pressure sensing apparatus constructed according to the present invention is indicated generally by the reference numeral 1 in FIG. 1. In the application shown in FIG. 1, apparatus 1 is a nebulizer operatively connected to a breathing circuit 2 and a control unit 4. Control unit 4 is typically located separately from nebulizer 1 but may be incorporated in ventilator 3, if desired.

#The substance to be nebulized typically comprises a solution, or a particulate or colloidal suspension, of a product but could comprise other substances, such as a dry fluid material. The substance may comprise water for humidification. For purposes of explanation, the fluid substance undergoing nebulization or atomization is hereinafter generally described as a liquid.

#Nebulizer 1 atomizes the liquid for delivery in a breathing gas flow to a subject, for example, as a drug treatment for a patient. Breathing circuit 2 includes an inhalation limb 5, one end of which is coupled to ventilator 3 at inhalation limb connector 6, and an exhalation limb 7, one end of which is connected to ventilator 3 at exhalation limb connector 8. Inhalation limb 5 and exhalation limb 7 are connected at their opposite ends to two adjacent arms 9a and 9b, respectively, of a Y-connector 9. A third arm 9c of the Y-connector 9 is connected to one end of patient limb 10. The other end of patient limb 10 is directed to a gas administration structure (not shown) for the subject, such as a mouthpiece, a facemask, or an endotracheal tube.

Vibrating element liquid discharging apparatus having gas pressure sensing

Life of this patent

Vibrating element liquid discharging apparatus having gas pressure sensing

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims87

Description13,077 words

Drawings

Classification5 codes

Life of this patent

Description13,077 words