JP2921976B2 - Expiratory valve device in ventilator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an exhalation valve device in a ventilator.

(Prior art and its problems) In a ventilator, an expiration circuit and an expiration circuit are connected to a common circuit connected to the lungs of a patient. From the inspiratory circuit, air whose humidity and oxygen concentration have been adjusted is supplied to a common circuit, that is, a patient's lung, while air after gas conversion by the patient's lung is externally passed through the exhalation circuit from the common circuit. Is discharged to And
The intake circuit is provided with an intake valve, while the exhalation circuit is provided with an exhalation valve.

The exhalation valve is used for controlling the exhalation pressure and the exhalation flow rate.
This is the so-called balloon type. That is, the valve body of the exhalation valve itself is formed of a balloon, and the degree of expansion of the balloon is changed to adjust the degree of opening of the exhalation circuit.

However, such a balloon-type exhalation valve has poor responsiveness and accuracy, and some measures are desired in this regard. For example, PEEP in ventilators
In the apparatus, it is desired to control the exhalation-valve with good responsiveness and high accuracy in order to maintain the PEEP pressure at a predetermined pressure, but such a demand could not be satisfied.

On the other hand, as another type of the exhalation valve, there is a so-called injection type. This is to inject air in the reverse flow direction into the expiration circuit and adjust the injection pressure and the injection amount, thereby performing substantially the same as the opening degree adjustment of the expiration circuit. . However, this injection type is still unsatisfactory in terms of its responsiveness and accuracy. In addition to this, as the air to be injected, a large amount of similarly adjusted intake gas is consumed, and therefore, it is actually used very little.

In order to solve the above-mentioned problems, the present applicant has already adopted a type in which the opening of the exhalation circuit is adjusted by a valve body as an exhalation valve, and a type in which the valve body is directly driven by a reciprocating electromagnetic actuator. Has been proposed (Japanese Patent Laid-Open No. 60-2929).
No. 65).

The present invention is based on the premise that the valve element is directly driven by a reciprocating electromagnetic actuator, and while fully satisfying the responsiveness and accuracy points, can be made compact as a whole. The purpose is to provide.

(Structure, operation, and effect of the invention) In the present invention (claim 1) for achieving the above object, a casing, a leaf spring held by the casing, and one face side of the leaf spring are opposed to each other. A valve seat member that is provided in the casing to guide exhalation from an exhalation circuit into the casing, and is attached to the leaf spring on one surface side of the leaf spring;
A valve body that is moved toward and away from the valve seat member in accordance with the displacement of the leaf spring in the plate thickness direction; and the leaf spring is housed in the casing on the other surface side of the leaf spring. Directly in the thickness direction,
An exhalation valve for a respirator, comprising: electromagnetic drive means for driving; and an exhalation release port formed on the one surface side of the leaf spring in the casing to release the inside of the casing to the atmosphere. It is configured as a device.

In order to achieve the above object, according to the present invention (claim 2), a casing, a leaf spring held by the casing, and an exhalation provided in the casing so as to face one surface of the leaf spring. A valve seat portion that guides exhalation from a circuit into the casing, and attached to the leaf spring on one surface side of the leaf spring;
A valve body that is moved toward and away from the valve seat member in accordance with a displacement of the leaf spring in a plate thickness direction; and an electromagnetic force formed between the leaf spring and a casing on the other surface side of the leaf spring. And an electromagnetic drive means for driving the leaf spring in the thickness direction thereof, wherein the valve body is pivotally supported with respect to the leaf spring. It is configured as a device.

In order to achieve the above object, according to the present invention (claim 3), a casing, a leaf spring held by the casing, and an exhalation provided in the casing so as to face one surface of the leaf spring. A valve seat member for guiding exhalation from a circuit into the casing, and attached to the leaf spring on one side of the leaf spring;
A valve body that is moved toward and away from the valve seat member in accordance with a displacement of the leaf spring in a plate thickness direction; and an electromagnetic force formed between the leaf spring and a casing on the other surface of the leaf spring. Electromagnetic driving means for driving the leaf spring in the thickness direction thereof, wherein the electromagnetic driving means is provided on the casing corresponding to the coil provided on the leaf spring and the coil And an exhalation-valve device in a ventilator, comprising a magnet.

According to the first aspect of the present invention, the exhalation-valve apparatus according to the present invention drives the leaf spring directly by controlling the electromagnetic driving means, that is, the current (voltage). The quantity can be changed responsively and accurately. The displacement of the leaf spring determines the relative position of the valve body with respect to the valve seat member, that is, the degree of opening of the exhalation circuit,
The degree of opening of the expiration circuit can be changed responsively and accurately to a desired one.

In addition, the leaf spring, the valve seat member, the valve body, and the electromagnetic driving means are effectively arranged with respect to the casing, so that the whole can be made compact. In particular, since the electromagnetic drive means of the leaf spring is arranged on the side opposite to the valve element and the valve seat member with the leaf spring interposed therebetween, the electromagnetic drive means also prevents the discharge of expiration through the valve seat member. There is no such thing as.

Further, since the valve body is attached to the leaf spring, the leaf spring can be used as a mounting member for the valve body, and at the same time, can also have a function as a return spring by utilizing its original spring property. .

According to the second aspect of the invention, the valve seat member is pivotally supported by the leaf spring, as a matter of course. This is preferable in that the valve body is securely brought into close contact with the valve body to obtain the reliable valve closing action.

According to the third aspect of the present invention, not only can the overall size be reduced while sufficiently satisfying the responsiveness and accuracy, but of course, an electrode can be supplied to the coil by using a coil and a magnet as the electromagnetic driving means. The leaf spring can be displaced in the plate thickness direction by the repulsive force between the coil and the magnet caused by the electromagnetic force generated when this occurs. In this case, the magnet is preferably provided integrally with the casing as a permanent magnet in order to secure the magnetic force as large as possible, and is preferably provided integrally with the coil leaf spring, which is small and lightweight.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, an example of the exhalation-valve device according to the present invention will be described first, and then a usage example of the exhalation-valve device according to the present invention and a comparative example of a conventional device will be described.

1, the exhalation valve device In FIG. 1, C is a casing, and this casing C is a bolted or screwed lower casing C1, an annular middle casing C2, and a closed tubular upper casing C3. It is configured by being integrated by coupling or the like.

The casing C holds a leaf spring 31.
More specifically, the leaf spring 31 is formed in a disk shape, and its outer peripheral edge is sandwiched between the middle casing C2 and the upper casing C3 via the waterproof packing 32. Such a leaf spring
Due to 31, the upper exhalation release space X
And a lower drive mechanism storage room Y. The exhalation release space X is always released to the atmosphere via a release port 33 opened on the top wall of the upper casing C3.

A cylindrical valve seat member 34 is screwed to the top wall of the upper casing C3, and is prevented from rotating by a lock nut 34A.
The valve seat member 34 extends in the up-down direction, the lower end opening is opened in the exhalation release space X, and the upper end portion is connected to the exhalation circuit using a joint or the like.

The lower end of the valve seat member 34 serves as a valve seat 34a.
A valve seat 35 is attached to the leaf spring 31 so as to face 4a. This valve element 35 is pivotally supported by the leaf spring 31. That is, a pivot bearing 36 having a spherical tip is fixed to the upper surface of the leaf spring 31, and a substantially conical recess 35 formed on the lower surface of the valve pair 35 is provided at the spherical tip of the pivot bearing 36.
a is inserted. Then, the valve body 35 and the pivot bearing 36
Are connected so as not to be separated from each other by an annular locking band 37 formed so as to surround the pivot bearing. The locking band is formed of an elastic material such as rubber so that the valve body 35 can swing 360 degrees around the spherical tip of the pivot bearing 36.

An electromagnetic drive mechanism D for driving the leaf spring 31 and thus the valve element 35 in the vertical direction is formed in the drive mechanism storage chamber Y. Hereinafter, the electromagnetic drive mechanism D will be described in detail.

First, an annular permanent magnet 41 is fixed to the lower casing C1. An annular inner magnetic pole member 42 is fixed to the upper surface of the permanent magnet. The lower casing C1 is made of a ferromagnetic material such as iron, and the inner surface of the upper end portion of the lower casing C1 forms an outer magnetic pole 43 facing the inner magnetic pole member.

On the other hand, a coil support member 44 is fixed to the lower surface of the leaf spring 31. The coil support member 44 has an annular coil holding portion 44a extending at a predetermined interval between the inner magnetic pole member 42 and the outer magnetic pole 43, and the coil 45 is held by the coil holding portion 44a. I have. Thus, a linear motor is constituted by the coil 45 and the magnetic poles 42 and 43.

A guide pin 46 extends downward and is integrated with the coil holding member 44, and the guide pin 46 is connected to the inner hole 42 of the inner magnetic pole member 42.
a and extends into the inner hole 41a of the permanent magnet 41 communicating therewith. A cylindrical guide member 47 such as Teflon having a small sliding resistance is fixed to the inner surface of the inner hole 42a of the inner magnetic pole member 42, and the guide pin 46 is smoothly guided by the guide member 47. The diameter of the inner hole 41a of the permanent magnet 41 is
It is made sufficiently larger than the outer shape of 6 to form an escape space for the guide pin 46.

The inner holes 41a and 42a, the guide pin 46, the spherical tip of the pivot bearing 36, and the valve seat member 34 are located on the center axis of the casing C. Of course, a lead wire (not shown) extending from outside the casing C is connected to the coil 45. In the figure, reference numeral 48 denotes an opening to the atmosphere.

The exhalation-valve apparatus configured as described above performs the following operations. First, when the valve body 35 is opened when the valve body 35 is separated from the valve seat 34a, the exhalation from the valve seat member 34 is released to the atmosphere from the release port 33 through the exhalation release space X. Leaf spring 31
As the valve is displaced upward, the valve body 35 approaches the valve seat member 34, that is, the valve seat 34a, and the opening degree of the valve seat member 34, that is, the opening degree of the expiration circuit is reduced. Thus, the opening of the expiration circuit is adjusted according to the vertical displacement of the leaf spring 31.

The vertical position of the leaf spring 31 is changed by controlling the current supplied to the coil 45. That is,
When the coil 45 is energized, it receives an electromagnetic driving force such that the energized coil 45 is displaced in the vertical direction (Fleming's law).
31 Therefore, it corresponds to the vertical displacement position of the valve body 35. The electromagnetic driving force is increased as the current (voltage) applied to the coil 45 increases. More specifically, when the current supplied to the coil 45 is zero, the valve body 35 is largely separated from the valve seat 34a and the opening degree of the expiration circuit becomes 100
%, When the coil 45 is energized, the coil 45 and thus the valve body 35 are displaced upward, and the amount of upward displacement is increased as the energizing current to the coil 45 is increased.

As described above, by controlling the current supplied to the coil 45, the opening degree of the valve seat member 34 and thus the expiration circuit is reduced.
It is varied in the range of 0-100%. Since the valve element 35 is pivotally supported by the leaf spring 31, the valve element 35 is connected to the valve seat 34a.
, And is reliably prevented from leaking when the valve is closed. Also, if the setting force of the locking band is relatively small, the valve body 35
While the valve is open from the valve seat 34a, the exhalation pressure from the valve seat member 34 is received to correct the valve body 35 to a position that is always perpendicular to the valve seat 34a. Can be uniformly discharged to the exhalation release space X.

Here, the magnet 41 can be an electromagnet. Further, the magnet 41 can be provided on the leaf spring 31 side, and the coil 41 can be provided on the casing C side. However, providing a magnet 41 in the casing C which requires a larger space and a heavier weight than the coil 45 is more advantageous in terms of a package in terms of a leaf spring.
31 Therefore, it is also preferable in reducing the reciprocating inertia of the valve body 35 and improving its responsiveness.

FIG. 2 shows an example of use of the exhalation valve device according to the present invention, and shows a case where the device is used for PEEP pressure control. In FIG. 2, 1 is a Y-shaped common circuit,
The merging end 1a is connected to the lung H of the patient (generally airtightly connected to the mouth of the patient via an adapter).
An intake circuit 2 is connected to one of the two branch ends 1b and 1c, and an expiration circuit 3 is connected to the other. The exhalation circuit 2 is connected to an air tank 4 as a pressure source, and the tank 4 stores air of a predetermined pressure which has been adjusted in humidity and oxygen concentration as known.

An electropneumatic converter 5 (voltage-pneumatic converter) as an intake pressure adjusting means is connected to the intake circuit 2. The exhalation circuit 3 is connected to (the valve seat member 34 of) the exhalation valve device according to the present invention via the joint 6.

In FIG. 2, reference numeral 8 denotes a control unit constituted by a microcomputer, which basically comprises a CPU, a ROM, and a RAM. For the control unit 8, each of a pressure sensor 9 and a PEEP pressure setting switch 10 is provided. A signal is input, and a signal V1 or V2 is output from the control unit 8 to the electropneumatic converter 5 and the coil 45 of the exhalation valve device. And outputs the detected pressure to the control unit 8 as a voltage signal PA. The switch 10 changes a set PEEP pressure, that is, a target PEEP pressure by manual operation, and outputs a voltage signal PT corresponding to the target PEEP pressure to the control unit 8. In the embodiment, the switch 10
Can set the PEEP pressure steplessly within the range of 5 cm to ₂₀ cmH ₂ O.

In the above configuration, the actual PEEP
The pressure, that is, the pressure detected by the pressure sensor 9, can be changed by the following factors, assuming that the patient's respiratory state is a certain stationary state. That is, by changing the pressure of the exhalation circuit 2, the actual PEEP pressure PA increases as the exhalation pressure increases. The adjustment of the intake pressure is performed by controlling the first electropneumatic converter 5.

By changing the opening degree of the exhalation valve device (valve seat member 34), the smaller the opening degree, the greater the exhalation discharge resistance from the exhalation circuit 3 and the actual PEEP pressure PA.

Next, the contents of control by the control unit 8 will be described with reference to the flowchart shown in FIG. In the following description, S indicates a step.

First, in S1, the target PE set by the switch 10 is set.
The EP pressure PT and the actual PEEP pressure PA of the common circuit 1 detected by the pressure sensor 9 are read. Next, in S2, PA
Is subtracted from PT to calculate the differential pressure ΔP. In S3, it is determined whether or not the differential pressure ΔP is equal to or greater than zero. When the determination in S3 is YES, the actual PEEP pressure PA
Is greater than or equal to the target PEEP pressure PT, and in this case, the output voltage signal to the electropneumatic converter 5 and the coil 45 of the exhalation valve device.
V1 and V2 are set as S4 or S5. That is,
In S4, V2 = 0 is set (no air supply from the expiration circuit 2). Also, it is set to _{V1 = K 1 × PT-K} 1 '× ΔP in S5. Note that K ₁ and K ₁ ′ are control gains, respectively. Thus, when the actual PEEP pressure PA is equal to or higher than the target PEEP pressure PT, S4 and S4 are used to reduce the actual PEEP pressure PA.
V1 and V2 in S5 are set.

After the above S5, in S6, it was set as described above
V1 and V2 are output to the electropneumatic converter 5 or the coil 45.

On the other hand, when the determination in S3 is NO, the actual PEEP pressure PA is too small than the target PEEP pressure PT. In this case, after ΔP is first converted into an absolute value in S7, after V1 and V2 are set in S8 and S9, V1 and V2 are output to the electropneumatic converter or the coil 45 in S6. when the route passing through, provided for increasing the actual PEEP pressure PA, is set to V2 = K ₂ × ΔP, also it is set to _{V1 = K 1 × (PT +} ΔP). Incidentally, K ₂ is a control gain.

Thus, while comparing the actual PEEP pressure PA with the target PEEP pressure PA, the voltage converter 5 and the coil 45 of the exhalation-valve device are controlled, and the pressure of the common circuit 1 (actual PEEP pressure PA) is set to the target value.
Maintained at PEEP pressure PA. Note that the control gains K ₁ , K ₁ ′, K ₂
May be obtained in advance by experiments.

FIG. 4 shows the effect of the case where the expiratory valve device according to the present invention is incorporated in the PEEP device (shown in FIG. 2) as compared with the PEEP device using the conventional expiratory valve device. 1 shows a test apparatus used to obtain data for performing the test. Note that, in FIG. 4, elements corresponding to those in FIG. 2 are denoted by reference numerals with “′”. In addition, as a PEEP device incorporating a conventional exhalation valve device, a Bennet 7200a which is currently said to be the world's highest level is used, but since this is a balloon type exhalation valve device,
The feedback control of the exhalation-valve device is not performed (it is impossible to perform the feedback control because of poor response).

First, reference numeral 21 in FIG. 4 is a device called HARVARD APPARATUS for artificially creating a constant respiratory state using a kind of cylinder device. With this device 21,
With a displacement of 670 cc (one breath), a breathing rate of 30 breaths / minute was artificially created. Reference numeral 22 denotes a hot wire type flow meter which is connected to the common circuit 1 'and measures the actual respiratory volume produced by the device 21. Further, in order to check the fluctuation state of the PEEP pressure, the actual pressure of the common circuit 1 'was measured by the pressure sensor 23 connected to the common circuit 1'. Then, a PEEP device incorporating the expiratory valve device according to the present invention or a conventional PEEP device is connected to the exhalation circuit 2 'and the exhalation circuit 3', and the respiratory volume V when the PEEP device is operated is determined. An actual PEEP pressure P and a PV diagram obtained by the both are obtained. More specifically, each signal from the flow meter 22 and the pressure sensor 23 is input to the microcomputer 24, and the above-mentioned “P”, “V” and “PV” are displayed on the display 25.
"Diagram" is displayed.

The data (PV diagram) obtained as described above are shown in FIGS. 5 (a) and (b) to FIGS. 8 (a) and (b). In each figure, (a) shows the case where the exhalation valve device according to the present invention is used, and (b) shows the case where the conventional exhalation valve device is used. Then, the Fig. 5 when the target PEEP pressure is 5 cmH ₂ O, FIG. 6 is a time target PEEP pressure is 10 cm H ₂ O, 7
The figure shows when the target PEEP pressure is 15 cmH ₂ O, and FIG. 8 shows the target PEEP pressure.
This is shown when the pressure is 20 cmH ₂ O.

As understood from FIGS. 5 (a) and (b) to FIGS. 8 (a) and (b), the exhalation valve device according to the present invention was used.
The PEEP device has a PEEP
It can be seen that the variation in pressure (P) is very small, which results in a significant reduction in the respiratory work of the patient (the respiratory work increases with the area enclosed by the PV diagram).

In the above embodiment, the case where the exhalation valve device is used for controlling the PEEP pressure has been described. However, the present invention is not limited to this, and can be used in various ways such as for controlling the exhalation pressure and the exhalation flow rate. Further, the leaf spring 31 may be formed in an elongated shape so that both ends thereof are held by the casing C.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing one embodiment of an exhalation valve device according to the present invention. FIG. 2 is a system diagram showing an example in which the exhalation valve device according to the present invention is used for PEEP pressure control. FIG. 3 is a flowchart showing a control example of the PEEP device shown in FIG. FIG. 4 is an overall system diagram showing a test device used to compare the effect of the exhalation valve device according to the present invention with a conventional device. 5 (a) to 8 (a) are diagrams showing test results of a PEEP device using the exhalation valve device according to the present invention. 5 (b) to 8 (b) show test results of a PEEP device using a conventional exhalation valve device as it is. C: Casing X: Expiration release space Y: Drive mechanism storage room D: Drive mechanism 31: Leaf spring 34: Valve seat member 34a: Valve seat 36: Pivot bearing 41: Magnet 42: Inner magnetic pole member 43: Outer magnetic pole 44: Coil Holding member 45: Coil

Claims (3)

(57) [Claims] 1. A casing, a leaf spring held by the casing, and a valve seat member provided on the casing so as to face one surface of the leaf spring and guiding exhalation from an exhalation circuit into the casing. A valve body that is attached to the leaf spring on one surface side of the leaf spring, and is moved toward and away from the valve seat member in accordance with displacement of the leaf spring in the thickness direction; and the other surface side of the leaf spring. An electromagnetic driving means for directly driving the leaf spring in the thickness direction thereof by an electromagnetic force, formed on the one surface side of the leaf spring in the casing, and exposing the inside of the casing to the atmosphere. An expiratory valve device in a ventilator, comprising: an exhalation release port for releasing. 2. A casing, a leaf spring held by the casing, and a valve seat member provided on the casing so as to face one surface of the leaf spring and guiding exhalation from an exhalation circuit into the casing. A valve body that is attached to the leaf spring on one surface side of the leaf spring, and is moved toward and away from the valve seat member in accordance with displacement of the leaf spring in the thickness direction; and the other surface side of the leaf spring. And electromagnetic driving means for driving the leaf spring in its thickness direction by electromagnetic force, wherein the valve body is pivotally supported with respect to the leaf spring. An expiratory valve device for a ventilator, comprising: 3. A casing, a leaf spring held by the casing, and a valve seat member provided on the casing so as to face one surface of the leaf spring and guiding exhalation from an exhalation circuit into the casing. A valve body that is attached to the leaf spring on one surface side of the leaf spring, and is moved toward and away from the valve seat member in accordance with displacement of the leaf spring in the thickness direction; and the other surface side of the leaf spring. And electromagnetic driving means for driving the leaf spring in its thickness direction by electromagnetic force, wherein the electromagnetic driving means is provided on the leaf spring. An expiratory valve device for a ventilator, comprising: a coil; and a magnet provided on the casing corresponding to the coil.