JPH0432772A - Device for detecting air flow through path - Google Patents

Abstract

PURPOSE: To detect an air flow through a passage by letting an air flow through a passage strike against a piezoelectric film sensor and generating an electric signal corresponding to the impact. CONSTITUTION: An automatic suction unit 10 comprises a tubular housing 12 having a small generally tubular passage 28. A piezoelectric film sensor 36 is formed in the passage 28 by first and second air flow limiters 40, 42. The limiters 40, 42 function as means for directing the air flow passing through the passage 28 toward the sensor 36. The air flow passing through the passage 28 (inspired gas of a user) causes a relatively large oscillation in the sensor 36 whereas the air flow in the opposite direction (expired gas) causes a relatively small oscillation in the sensor 36. An electric signal of high amplitude (inspired gas) generated from the sensor 36 is discriminated from an electric signal of low amplitude (expired gas) and a fluid is discharged from an aerosol container 14 into the housing 12 only for an appropriate time.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus for detecting air flow through passageways, and more particularly, to not only detect the presence of airflow, but also detect the presence of airflow through such passageways. This invention relates to devices for detecting direction and magnitude. In one embodiment, the present invention is suitable for use in an inhalation device for dispensing fluids or administering medications to a user.

DESCRIPTION OF THE PRIOR ART Small, portable inhalation devices are in widespread use, particularly for administering prescribed doses of aerosol medications to people with respiratory failure conditions such as asthma or other conditions. Such devices typically include a plastic, generally tubular, generally L-shaped housing at one end adapted to receive an aerosol container or module containing some form of propellant as well as a drug. The other end of the housing is provided with a mouthpiece adapted for insertion into the mouth of the user. The housing also includes a mouthpiece of some kind for releasing the drug from the aerosol container for inhalation by the user. An actuation device is also included, typically requiring the aerosol container to be moved inwardly relative to the housing to release the drug.

As mentioned earlier, inhalation devices of the type described are widely used for dispensing such drugs. However, many people are unable to utilize these devices successfully. Devices generally require that the aerosol container be moved relative to the housing to release the drug into the housing substantially simultaneously with or shortly after inhalation in order to receive the full benefit of the drug. Due to illness, old age, etc., many people are unable to carry out such two-step processes simultaneously or quickly. Eventually, they also do so and do not have access to inhalation devices at all, or in some cases use drugs. only partially benefit from it.

[Purpose of the invention]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an inhalation device that can solve the problems of conventional devices as described above.

[Structure of the Invention] The present invention is used as part of an automatic inhalation device in which only a single action is required on the part of the user, or part of the inhaler. Detects inhalation by the user and thereby
Means is provided for automatically activating the aerosol container to release a predetermined amount or dose of drug without any further action by the user.

In another embodiment, the invention may be used to monitor a user's breathing. For example, the present invention may be used with tracheal tubes, mouth- or nose-inserted breathing tubes to monitor a user's breathing. The present invention allows for monitoring not only changes in breathing rate, but also breathing rate and depth of breath.

Briefly, the present invention is a device for detecting air flow through a passage having a first opening and a second opening for flowing air, the air flowing in through the first opening. The liquid then flows through the passage either in a first direction outflowing from the second opening or in a second direction flowing in from the second opening and outflowing from the first opening. The device includes a piezoelectric film sensor positioned within the passageway. Flow directing means are provided within the passageway for directing air towards the piezoelectric film sensor. The piezoelectric film sensor has a first
and a second electrical signal if the air flows in a second direction. Discrimination means electrically coupled to the piezoelectric film sensor is provided for receiving the first electrical signal and the second electrical signal and thereby identifying the direction of air flowing through the passageway.

DESCRIPTION OF THE EMBODIMENTS Like reference numbers represent like elements.
The figure illustrates a partially cut away side view of a preferred embodiment of an automatic inhalation device 10 according to the present invention. Automatic inhalation device 10 generally includes a tubular housing 2 similar in size and shape to that of currently available inhalation devices.

As shown in FIG. 1, the housing 2 is generally L-shaped in cross section. Preferably, housing 12 is constructed from a lightweight, high strength plastic material of the type currently available and used for manufacturing inhalation devices. However, as will be apparent to those skilled in the art, the housing may be constructed from any other suitable material, and the housing may be of any other size and or shape.

The housing 12 includes means for receiving and engaging an aerosol container or module 4 containing a fluid or drug to be dispensed under pressure. Aerosol containers of this type are generally well known in the art and are available from a number of manufacturers. These aerosol containers generally contain a predetermined amount of the above-mentioned fluid or other drug, together with a suitable propellant, usually a gas. The push-down valve is adapted to release the fluid or drug when depressed by the user. These aerosol containers are generally cylindrical in shape; may vary in diameter and/or length depending on the amount of drug. In the presently preferred embodiment, housing 12 is generally cylindrical, with an inner diameter or portion of the housing wall surrounding aerosol container 14 extending therethrough. The aerosol container 14 is at least slightly larger than the outer diameter of the aerosol container 14 so that air can freely pass through it. Like inhalers currently in use, the aerosol container 14 can be conveniently removed from the housing 12 when completely exhausted and replaced with a new filled aerosol container.

This allows the inhalation device 10 to use different aerosol containers in the series.

In the presently preferred embodiment of the invention, the valve 16 of the aerosol container 14 is adapted for insertion within one end of a generally tubular, L-shaped conduit 18.

A portion of the aerosol container 14
is held in place and valve 16 is pressed down 2 to open as shown when inserted into conduit 18 and to allow pressurized fluid to flow into conduit 18. . The other end of conduit 18 is secured to one end of a low power mechanical actuation means. In the presently preferred embodiment, the actuation means comprises a valve 20 formed using shape memory alloy fibers. This type of valve is generally well known in the art and is manufactured by Tokia in Ilvain, California.
It is commercially available from merica Technologies and sold under the category "BIOMETAI".

A complete description of the construction and operation of such valves is available from the manufacturer and is not necessary for a complete understanding of the invention. Suffice it to say that the valves are generally tubular and generally include a single fiber of a shape memory alloy such as titanium-nickel. Such fibers are in the range of 6 mils in diameter and, depending on their structure, operate like human muscles. By passing a small current on the order of about 300 milliamps through the fibers at a low voltage on the order of 15 volts, the fibers contract, thereby opening the valve. When the current flowing through the fiber is stopped, the fiber relaxes or expands and returns to its original position, closing the valve. A discharge opening 22 is provided at the other end of the valve 20.

Valve 20 thus substantially replaces valve 16, and when valve 20 is actuated, fluid flows into aerosol container 1.
4 into the housing 12. For those skilled in the art,
Although the BIOMETA valve is currently preferred, it will be appreciated that other lightweight, low pressure mechanical or electromechanical actuators may be used.

Housing 12 also includes a mouthpiece 24 for engaging the user's mouth in the same manner as inhalation devices currently in use. The mouthpiece 24 has a discharge opening 22
It has a mouthpiece opening 26 adjacent to it. When a user positions their mouth over mouthpiece 24 and inhales, air is forced through housing 12 (around aerosol container 14) and into the user's mouth through mouthpiece opening 26. This causes the fluid or drug released into the housing through the release opening 22 to be inhaled.

Housing 12 also includes a small, generally cylindrical passageway 28. The passageway 28 is located lower within the housing 12 and proximate the mouthpiece 24 in the presently preferred embodiment. Those skilled in the art will recognize that the passageway 28 may alternatively be located at other locations within the housing 12. A first end 30 of the passageway 28 is open to the atmosphere beyond where the user would position the mouth for air intake. A second end 32 of passageway 28 communicates with mouthpiece opening 26 . Thus, when a user positions their mouth over mouthpiece 24 and inhales, a small portion of the inhaled air flows through passageway 28, as shown by arrow 34.

Detection means are provided within the passageway 28 for detecting the user's inhalation through the mouthpiece opening 26 and generating an electrical signal in response. In the presently preferred embodiment, the sensing means includes a piezoelectric film sensor 36. The piezoelectric film sensor 36 is preferably formed from an electrode-coated, unthin layer of piezoelectric polymer film of the type commercially available from Pennwalt Co., Philadelphia, Pennsylvania under the name KYNAR piezoelectric film. be done. Piezoelectric film sensor 6 is also available. It also includes a pair of electrical wires coupled to the control means in a manner to be disclosed hereinafter.

Piezoelectric film sensor 36 may be formed from an elongated piezoelectric or other suitable film material.

In a presently preferred embodiment, piezoelectric film sensor 36
detects intake air based on the presence of air flowing through the passage 28. Alternatively, the piezoelectric film sensor 36 is
It can be used to detect a change in the temperature of the air flowing through the passage, ie, the user's exhaled air is warmer or the air he inhales is cooler.

A piezoelectric film sensor 36 is generally located at the first end 30 of the passageway.
It is generally positioned within a bulge-shaped space 38 formed within the passageway 28 by a first airflow restrictor 40 facing the passageway and a second airflow restriction βR body 42 generally facing the second end 32 of the passageway. First air flow restrictor 40 and second air flow restrictor 42 are preferably formed from the same material used to form housing 12, or may otherwise be formed from any other suitable material. obtain. In the presently preferred embodiment, the first air flow restrictor 40 and the second air flow restrictor 42 have a generally circular first aperture 44 and a second aperture 46, respectively, centered within the passageway. Annular to define.

The first air flow restrictor 40 and the second air flow restrictor 42 act as directing means for directing the air flow through the passageway 28 to impinge on the piezoelectric film sensor 36. It is understood by those skilled in the art that the first air flow restrictor 40 and the second air flow restrictor 42 need not be annular, and that the first aperture 44 and the second aperture 46 be circular and not centered within the passageway 28. (Let's recognize that this is a good thing.

In the presently preferred embodiment, a generally circular aperture 48 also extends through the piezoelectric film sensor 36. The aperture 48 may also have a shape other than circular if desired.

As best shown in FIGS. 1 and 2, first aperture 44 has a larger diameter than second aperture 46. As best shown in FIGS. Similarly, the diameter of aperture 48 is preferably at least slightly larger than that of second aperture 46.

The piezoelectric film sensor 36 is located inside the cup-shaped space 38.
Note that the air flow restrictor 42 is positioned proximate to the airflow restrictor 42 of the The piezoelectric film sensor 36 is thus mounted inside the cup-shaped space 38, and the first opening 44,
The reason for changing the diameters of the second openings 46 and 48 in this way is to make it possible to identify the flow direction of the air flowing through the passage 28 based on the degree of vibration of the piezoelectric film sensor 36. . Air flow (due to user inhalation) through the passageway 28 in the direction indicated by the arrow 34 is directed against the piezoelectric film sensor 36 because the first opening 44 has a relatively large dimension with respect to the cup-shaped space 38. It has a strong impact force and causes relatively large vibrations in the piezoelectric film sensor 36. As a result, when the user inhales, a relatively large amplitude electrical signal is generated by the piezoelectric film sensor 36, as indicated by the reference numeral 50 in FIG. Alternatively, arrow 8134
Because the dimensions of the circular second aperture 46 are relatively small, the air flow (user exhaust air) in the direction opposite to the flow indicated by is impinging on a relatively small portion of the piezoelectric film sensor 36. The sensor 36 is caused to vibrate to a relatively small degree, causing a relatively small amplitude electrical signal to be generated by the piezoelectric film sensor 36, as shown at 52 in FIG. Piezoelectric film sensor 3
By distinguishing between large-amplitude electrical signals (inhalation) and small-amplitude electrical signals (exhaust) generated from
Fluid is discharged from the aerosol container 14 into the housing 12.

The device 10 further includes control means 54 within the housing 12. The control means 54 is electrically connected to the detection means or piezoelectric film sensor for receiving an air flow electrical signal from the detection means and generating an actuation signal in response to receiving the electrical signal. The control means 54 is also electrically connected to the actuating means or valve 20 in order to send an actuating signal to the actuating means or valve 20 to cause it to open. In the presently preferred embodiment, the control means 54 preferably includes:
Inside the lower end of the housing 12 (see FIG. 1) is a valve 20.
is positioned close to the However, the control means 54 may be positioned at any suitable location within the housing 12.

FIG. 3 is a functional block diagram of a presently preferred embodiment of control means 54. Preferably, the airflow electrical signal from the piezoelectric film sensor 36 is first applied to a first discriminator, such as a filter 56. In the presently preferred embodiment, filter 56 is a bypass filter that filters out unwanted low frequency signals from piezoelectric film sensor 36. Such low frequency signals may be generated by heat, other noise, and/or vibrations that are not representative of what the piezoelectric film sensor 36 is detecting, ie, the operation of the intake air. The filtered signal from the piezoelectric film sensor 36 is then applied to a second identification device, such as a comparator 58, which compares the amplitude of the filtered signal to a predetermined reference value. The predetermined reference value is established as being of an amplitude greater than the level of the signal generated by the piezoelectric film sensor 36 during user exhaustion, as shown in FIG. When a signal with an amplitude greater than the predetermined reference value is received, comparator 58 immediately generates an electrical trigger signal, which is applied to dosing regulator 60 . The dosing regulator 60 operates as a timing device and, when actuated by an electrical trigger signal from the comparator 58, dispenses a desired amount of fluid or a desired dose of drug from the aerosol container 4 to the housing 12. An actuation signal of a predetermined length corresponding to the time required to open the valve 20 is generated.

The length of the actuation signal can be varied depending on the particular type of fluid or drug being dispensed and the needs of the particular user.

The control means 54 also includes a power source 62. In the presently preferred embodiment, the power source 62 is small and is an electric battery of the type commonly used in hearing aids or watches, although other power sources such as solar cells may be used. Power from the power supply 62 is supplied to the control means 54 through an actuation switch 64.
Applies to other parts of. In the presently preferred embodiment, actuation switch 64 carries a small push-button type switch located near control means 54 in housing 12. However, those skilled in the art will recognize that activation switch 64 may include any other suitable type of switch, such as a slide switch, and may be located at any other suitable location within housing 12. The activation switch 64 is intended to act as a safety device to prevent unauthorized activation of the aerosol container 14, thereby preventing undesired loss of fluid or drug.

FIG. 4 is a presently preferred electrical circuit diagram for implementing the schematic functional block diagram shown in FIG. The electrical circuit shown in FIG. 4 is mainly composed of individual components. Those skilled in the art will recognize that other types of discrete components may alternatively be used to perform the same function. Those skilled in the art will also recognize that the same functionality may be otherwise accomplished using other forms of electronic circuitry, such as custom or semi-custom integrated circuits or chips, in a manner well known in the art. .

Referring to FIG. 4, bypass filter 56 is comprised of resistor R2 and capacitor C1. It is implemented using an RC filter, the value of which is determined by the path and/or the frequencies that are desired to be excluded. Register R1 acts as a stabilization resistor.

The function of comparator 58 is performed by operational amplifier OA1. The operational amplifier OAI receives the output from resistor R2 and capacitor C1 from its positive input terminal. The negative input terminal of operational amplifier OAI is coupled to a voltage divider formed by resistors R3 and R4 for establishing a predetermined reference value or threshold voltage. The values for resistors R3 and R4 are determined by the piezoelectric film sensor 36 during user evacuation.
is selected to provide a reference value or threshold voltage that is greater than the maximum amplitude of the electrical signal generated by. When an inspiratory signal greater than the reference value or threshold voltage at the negative input terminal (denoted A in FIG. 5) is received at the positive input terminal, the operational amplifier OAI performs the timing control of FIG. Generates an output trigger signal in the form of a small positive voltage pulse shown in the diagram.

The output trigger signal from the operational amplifier OA+ is applied to the input terminal of the first timer T1.

In the presently preferred embodiment, the first timer T1 is "453".
It is an 8° timer or one shot. In another way, “5
A 55° timer may be used. These two devices are well known in the art and are commercially available. Other timers or related components or circuits may alternatively be used. Timer T1 functions as a dosing regulator 60 and generates an activation signal as indicated by C in the timing diagram of FIG. The length of the actuation signal is established by the time constant of the RC circuit formed by the R5C2 filter. As previously discussed, the time constant of timer T1 may vary depending on the amount of fluid or drug released into housing 12, depending on the characteristics (i.e., strength) of the particular drug and/or fluid and/or characteristics of the user. may be modified to vary the dosage.

The activating signal from timer TI is applied to the gate terminal of a field effect transistor (FET) Q, a switching transistor or device of the ground type. When an actuation signal is applied, field effect transistor Q1 becomes conductive, thereby allowing current to flow through the actuator or valve 20 to cause said valve 20 to open for the time of the actuation signal, thereby causing a predetermined amount. of the fluid or drug is released into the housing 12. Interrupting the timing circuit with resistor R5 and capacitor C2 stops the actuating signal from timer T1, causing field effect transistor Q to become non-conductive again, stopping current flow to valve 20, and causing valve 20 to close. Release of fluid or drug into housing 12 is stopped.

A second timer T2, preferably a "4538" timer, but alternatively any other timer or similar circuit, also receives the output trigger signal from the operational amplifier OAI and is shown in the timing diagram of FIG. generates a positive output signal shown as . The output signal of the second timer T2 is applied to the gate of a second field effect transistor FET Q2 or other switching transistor or device. The gate of the second field effect transistor Q2 and other switching transistors or devices eventually becomes R2C
1 is coupled between the input to the filter and ground. When the signal from the second timer T2 is received and the second field effect transistor q2 becomes conductive, the piezoelectric film sensor 3
Further signals from 6 are connected to ground through said second field effect transistor 02 and thus applied to operational amplifier OA+.

In this way, the second actuation signal from the operational amplifier OAI and the first timer T1 is prevented from occurring for a second predetermined period of time corresponding to the signal length indicated by line D in FIG. Ru. Since the second predetermined time period is longer than the first predetermined time period (indicated by C in FIG. 5), subsequent malfunctions of the aerosol container 14 due to a long inhalation or a series of short inhalations are prevented.

The functions of power supply 62 and activation switch 64 are illustrated in FIG. 4 by battery VB, switch SWI, and voltage regulator VRI. All of these components are of a type well known in the art.

To use the inhalation device O, the user first assembles the aerosol container 14 containing the desired fluid or drug into the housing 12 into the position shown in FIG. Mouthpiece 24 is then positioned within the user's mouth and activation switch 64 is depressed. As previously discussed, power is provided to the circuit by depressing the activation switch 64 and the control means 54 is then enabled. Air is then drawn around aerosol container 14 and through passageway 28 in the direction of arrow 34 and into housing 12 by the user inhaling. The flow of air through passageway 28 causes piezoelectric film sensor 36 to vibrate as previously described, thereby generating airflow electrical signal 50. If the airflow electrical signal 50 exceeds a reference value or threshold signal (indicating inspiration), a first predetermined length activation signal C is activated.
is generated. This actuation signal C is used to apply electrical current through the shaved metal valve 20. Such application of an actuation signal causes the shaved metal valve 20 to open for a first predetermined period of time, which causes the aerosol container 14 to dispense a predetermined amount of fluid or medicament into the housing 12 near the mouthpiece opening 26. Let it be released.

Inhalation by the user draws additional air into the housing from both the passageway 28 and the surroundings of the aerosol container 14;
The additional air carries the released fluid or drug into the user's mouth and subsequently into the user's lungs.

A first predetermined period of time C has elapsed and the appropriate amount of fluid or drug has been
Once the aerosol container 14 is inhaled and inhaled by the user, a second timer T2 prevents further activation of the aerosol container 14 even with continued inhalation by the user. When the user receives or takes fluid or medication, the activation switch 64 activates the control means 5.
4 to remove and/or stop power from the aerosol container 14, thereby preventing further movement of the aerosol container 14.

Referring to FIG. 6, a breathing tube device 110 according to the present invention is shown. Breathing tube device 110 generally includes a flexible tubular member 112 , which includes tubular member 11 .
2 has a free or unattached end 114 adapted to be inserted into a user's mouth or nose in a manner well known in the art. The other end of tubular member 112 is secured to a generally cylindrical connector member 116, also of a type generally known in the art. The connector member 116 is generally a cylindrical housing 1.
It is removably fixed to one end of 18. Housing 11
8 is a pair of generally annular flange members 120a and 1
It is formed from two engaged subhousings 118a2 and 118b interconnected by 20b. A second connector member, shown in phantom line 122, may be used to provide communication through a flexible second tubular member 124 to a ventilator, shown in phantom line 26. Alternatively, the other end or distal end 121 of the housing 118 may be
It can be in a non-attached state as shown by the solid line in FIG.

A generally cylindrical passageway substantially identical to passageway 28 (not shown in FIG. 6) extends through the entire housing 118 to a second passageway.
Distracted in substantially the same manner as shown in the figures. The passageway has a first opening adjacent the distal end 21 of the housing 118 and a second opening adjacent the connector member 116. Housing 118 also includes a first ventilator, a second ventilator (not shown), and a piezoelectric film sensor shown in phantom 119. The piezoelectric film sensor 119 is secured within the passageway of the housing 118 in substantially the same manner as the corresponding component shown in FIG. A suitable electrical wire or lead 128 is connected to the housing 118.
Internally, an electrical circuit in the form of a discriminator 130 extends from the piezoelectric film sensor 119. In the presently preferred embodiment, flexible tubular member 112, like connector member 116 and housing 118, is preferably formed from plastic materials of a type well known in the art and commonly used to form such components. be done. However, these parts may be formed from other materials suitable for the intended purpose as will become apparent.

One particular use for breathing tube device 110 is to detect airflow into and out of a user's lungs. In such use, the flexible tubular member 12 is installed within the user's mouth or nose.

Alternatively, housing 118 may be coupled to the distal end of a tracheal tube (not shown) using a suitable connector member.

A distal end 121 of housing 118 spaced from connector member 116 is generally open to the atmosphere, thus forming a first opening to the passageway substantially similar to opening 30 of FIG. Similarly, a second opening within the passageway is connected to the connector member 1.
16 and, via a flexible tubular member 112, to the user's ventilator. Inhalation by the user thus causes air to flow into the passageway through the first opening and exit the passageway through the second opening.

Similarly, the user's exhaust air causes air to enter the passageway through the second opening and exit the passageway through the first opening.

As previously described in detail with respect to FIG. 2, two ventilators (not shown in FIG. 6) are located at housing 118.
A flow directing means is provided for directing the air flow therethrough to impinge on the piezoelectric film sensor 119. Second
As in the piezoelectric film sensor described in connection with the figures, piezoelectric film sensor 119 generates a first electrical signal upon the user's inspiration and a second electrical signal in response to the user's exhaust. Examples of this type of electrical signal are shown in FIG. 5 by reference numerals 50 and 52, respectively.

Electric signal beam from piezoelectric film sensor 119
8 along with the discriminator 130. Discriminator 1
30 discriminates or differentiates between the two electrical signals to identify the user's intake and exhaust air. Figure 7 shows the discriminator unit 3.
A functional schematic block diagram of 0 is shown. Discriminator 130 includes a filter 132 that is used to filter out noise and other unspecified signals received by piezoelectric film sensor 119. The filtered signals from the piezoelectric film sensor are then applied to a comparator 134, which compares the signals to one or more fixed reference values. Comparator 134 produces an output signal to indicate the presence of airflow caused by inhalation or airflow caused by exhaustion. Discriminator 130 may be implemented by one skilled in the art using circuitry similar to control means 54 as shown in FIG. 4 and described in detail above. Alternatively, the discriminator may be implemented using other components and/or integrated circuits.

The output signal from comparator 134 may be used to monitor various aspects of the user's breathing. For example, the output signal may include a counter or other such accumulating device (not shown).
, and the user's ventilation rate can be counted or calculated by these devices. The ventilation rate may then be visually displayed using known display devices for immediate use by doctors, nurses, medical assistants, etc. to analyze the user's breathing status. Alternatively, the ventilation rate may be continuously recorded on a chart or other suitable storage media for continued observation and analysis of the user's ventilation rate over time. The ventilation rate is also electrically connected to the one or more preset limits to generate an audible or other alarm if it exceeds any of the one or more preset limits. can be compared.

The output signal from comparator 134 may also be used to determine the depth of a user's breathing or the magnitude of airflow into and out of the user's lungs. It should be appreciated that the amplitude of the electrical signal generated by piezoelectric film sensor 119 is proportional to the volumetric flow rate of air flowing through the passageway. Similarly, the length of the electrical signal generated is proportional to the user's inspiration time. The amplitude and length of the output signal from comparator 134 similarly corresponds to air volume flow and time. By knowing the dimensions or cross-sectional areas of the passageway and the various openings through the passageway in relation to the volumetric flow rate and the length of the intake or exhaust signal, the user can calculate the can determine the depth of breathing. Additionally, suitable circuitry (not shown) may be developed to automatically calculate the depth of a user's breaths after suitable calibration of a particular breathing tube device 110.

Another use for the invention is to detect the presence of air flow through a passageway. Here, a breathing tube 110 is used to detect whether or not the user is breathing.
Other such devices may be used. If the output signal from comparator 134 is absent for a predetermined period of time, ventilator 126 may be activated on demand to assist the user in breathing.

From the above description, it will be appreciated that the present invention includes an apparatus for determining the presence and/or direction of airflow through a passageway. Although the present invention has been described above with reference to specific examples,
It is to be understood that many modifications may be made within the invention.

[Brief explanation of drawings]

FIG. 1 is a partially cut away side view of an intake device according to the invention. Figure 2 is an enlarged view of the park shown in Figure 1. FIG. 3 is a schematic block diagram illustrating the operation of the apparatus of FIG. FIG. 4 is a circuit diagram illustrating a preferred embodiment of the schematic block diagram of FIG. FIG. 5 is a timing diagram representing signals generated in connection with operation of the circuit diagram of FIG. FIG. 6 is a side view of a breathing tube illustrating another embodiment of the invention. FIG. 7 is a schematic block diagram used in the apparatus shown in FIG. The names of the main parts in the figure are as follows. 10 automatic inhalation device 12: housing 14: aerosol container 18z conduit 20: valve 22: discharge opening 24: mouthpiece 26: mouthpiece opening 28: passage 30: first end 32: second end 36: piezoelectric film sensor 40 : first air flow restrictor 42 : second air flow restrictor 44 , first aperture 46 : second aperture 48 : aperture 54 : control means 56/filter 58 : comparator dosing regulator 62 , power supply 64 : actuation switch for

Claims (1)

[Claims] 1. An apparatus for detecting the presence of air flow through a passageway comprising a first opening and a second opening for air circulation, the apparatus comprising: a device for detecting the presence of airflow through a passageway, the apparatus comprising: a piezoelectric film sensor for directing an air flow passing through the passageway to impinge on the piezoelectric film sensor and cause the piezoelectric film sensor to generate an electrical signal responsive to the impingement; and air flow directing means. 2. a first passage of air through a passageway comprising a first opening and a second opening for communicating air, the air entering into said first opening and exiting from said second opening; or a second direction in which the air enters a second aperture and exits the first aperture, the piezoelectric film being positioned within the passageway; a sensor; causing an air flow passing through the passageway to impinge on the piezoelectric film sensor, and when the air flows through the passageway in the first direction, causing the piezoelectric film sensor to impinge upon the piezoelectric film sensor in response to the impingement; generating a first electrical signal and causing the piezoelectric film sensor to generate a second electrical signal in response to the impingement when the air flows through the passageway in the second direction; , air flow directing means for directing air flow through the passageway to the piezoelectric film sensor; and receiving the first electrical signal and the second electrical signal and directing the two electrical signals through the passageway. and discriminating means electrically coupled to the piezoelectric film sensor for discriminating to identify the direction of air flow. 3. Air flow directing means directing the air flow through the passageway in a first direction to impinge on the piezoelectric film sensor with a first force, and directing the air flow through the passageway in a second direction. 3. The apparatus according to claim 2, wherein the piezoelectric film sensor is caused to strike the piezoelectric film sensor with a second force equal to the first force. 4. The amplitude of the first electrical signal is greater than that of the second electrical signal, and the discriminating means discriminates the two electrical signals by comparing the amplitudes of the two electrical signals with a predetermined reference value. The device according to item 2 of the scope of the invention. 5. The air flow directing means includes a first restrictor facing the first opening within the passageway and a second restrictor facing the second opening within the passageway.
3. The device of claim 2, further comprising a limiting body, wherein the piezoelectric film sensor is positioned between the first limiting body and the second limiting body. 6. The first limiter forms an opening in a first predetermined area, the second limiter forms an opening in a second predetermined area, and the first limiter forms an opening in a second predetermined area;
3. The apparatus of claim 2, wherein the predetermined area is larger than the second predetermined area. 7. A device for detecting the direction of air flow into and out of a user's lungs, the passageway having a first opening and a second opening, the second opening being connected to the user's artificial respiration system. such that inhalation by a user causes air to flow into the passageway through the first opening and air to flow out of the passageway through the second opening, and exhaust air by the user causes air to flow into the passageway through the second opening. a passageway for allowing air to enter the passageway through a second opening and for air to exit the passageway through the first opening; a piezoelectric sensor within the passageway; and air flow directing means within the passageway. and causes the air flow to impinge on the piezoelectric sensor through the passageway, causing the piezoelectric sensor to generate a first electrical signal when the user inhales and a second electrical signal when the user exhales. the air flow directing means adapted to generate an electrical signal; and receiving the first electrical signal and the second electrical signal and using the two electrical signals to identify a direction of air flow through the passageway. and discriminating means electrically coupled to the piezoelectric film sensor for discriminating the piezoelectric film sensor. 8. The air flow detection means detects when the user inhales.
directing airflow through the passageway to impinge on the piezoelectric sensor with a first force; and upon exhaustion of a user, causing airflow through the passageway to impinge on the piezoelectric sensor with a second force equal to the first force; 8. The device according to claim 7, wherein the device is adapted to be caused to strike a target. 9. The amplitude of the first electrical signal is greater than that of the second electrical signal, and the discriminating means discriminates the two electrical signals by comparing the amplitudes of the two electrical signals with a predetermined reference value. The device according to item 7. 10. The air flow directing means has a first restriction body facing the first opening in the passageway and a second restriction body facing the second opening in the passageway, and the piezoelectric film sensor has a first restriction body facing the first opening in the passageway. 8. The device of claim 7, wherein the device is positioned between the limiting body and the second limiting body. 11. The first restriction body forms an opening in a first predetermined area;
8. The apparatus of claim 7, wherein the second restriction defines an opening in a second predetermined area, the first predetermined area being larger than the second predetermined area. 12. A device for detecting the magnitude of air flow to the lungs of a user, the passage having a first opening, a second opening, and a predetermined cross-sectional area, the second opening ventilator system, such that inhalation by a user causes air to flow through the first passageway into the passageway and through the second opening and out of the passageway. a piezoelectric sensor within the passageway; an air flow directing means within the passageway to direct a flow of intake air through the passageway and impinge on the piezoelectric sensor; said air flow directing means for generating an electrical signal having an amplitude corresponding to the volumetric flow rate of the air flow therethrough and having a time corresponding to the length of said air intake; and receiving said electrical signal and thereby generating a digital output. a discriminator means coupled to said piezoelectric sensor for generating a signal, said digital output signal having a pulse height proportional to the volumetric flow rate of air through said passageway and corresponding to the time of inhalation by the user; said discriminator means comprising a pulse having a pulse width, said pulse being used in conjunction with the cross-sectional area of said passageway to determine the amount of air entering the user's lungs. 13. Air passing through a passageway having a first opening and a second opening for air circulation, the air passing through the passageway having a first opening and a second opening for air circulation;
or the air flows into the second opening and exits from the second opening in the first direction;
A method for detecting airflow in a second direction exiting an opening in a passageway, the method comprising: providing a piezoelectric sensor within the passageway; and directing the airflow through the passageway to impinge on the piezoelectric sensor. providing a flow directing means for generating a first electrical signal when the airflow passes through the passageway in a first direction and a second electrical signal when the airflow passes through the passageway in a second direction; and discriminating between the two electrical signals to identify the direction of air passing through the passageway. 14. A first force causes the air to impinge on the piezoelectric sensor when the air passes through the passageway in a first direction, and causes the air to impinge on the piezoelectric sensor when the air passes through the passageway in a second direction. 14. The method of claim 13, including the step of impacting the piezoelectric sensor with a force of 2. 15. The method of claim 13, wherein the air flow is generated by the user's breathing.