SU1292731A1 - Respiratory tube of pneumotachograph - Google Patents

Abstract

The invention relates to the field of medicine and can be used to study breathing. The chain of invention is the reduction of the influence of artifacts. The tube contains a confuser 1, connected to the mouthpiece 2 of the patient, a diffuser 3, open to the atmosphere, and a receiving element 4 of the air flow sensor. The radii of the arcs of the circles forming the confuior are from 1.0 to 2.0 diameters of the smallest cross section of the confuser. The ratio of the smallest and largest sections of its areas is from 0.64 to 0.25. 1 il. c (O (L

Description

The invention relates to medical technology, namely to devices for the study of respiration.

The aim of the invention is to reduce the effect of artifacts caused by the effect of dead space.

The drawing shows a schematic of a breathing tube.

The tube contains a confuser 1, connected to the mouthpiece (or mouthpiece) 2 of the patient, the diffuser 3, open to the atmosphere, and the receiving element 4 of the air flow sensor. The profile of the confuser generatrix is made by arcs of two circles with centers 0 (and Oj 5 lying in the largest planes. C, and the smallest Cg sections of the confuser with radii from 1.0 to 2.0 diameters D.

The degree of constriction, confuser, defined by the ratio of the areas of its smallest and largest sections, is from 0.64 to 0.25.

With the indicated dimensions of the breathing tube and the total length of the confuser, equal to (0.8-2.0) Dd, the velocity distribution plot is leveled at the installation site of the receiving element 4.

The diffuser 3 is made along an arc of a circle with a radius of 2 Dd and with center 0 lying in the junction plane of the diffuser 3 with confuser 1.

Such an embodiment of the diffuser 3 for the purposes of pneumotachography provides satisfactory results both with respect to flow resistance and the shape of the velocity distribution plot at the installation site, the receiving element 4 of the air flow sensor 5 and with respect to the dead space of the breathing tube,

In the breathing tube, the confuser 1 with the diffuser 3 is conjugated along the smallest section, so that they have a common longitudinal axis.

Thus, the total length of the described breathing tube is (O, 95-2.2) Other, which provides the minimum dead space of the breathing tube and, consequently, improves the accuracy of the study of multiple breathing by reducing the effect of artifacts due to the effect of dead space. ,

Pneumotachograph with a breathing tube works as follows.

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The patient is attached to device 2 through device 2 (к {sleeve or mouthpiece) to the breathing tube. When you inhale air through the diffuser 3 enters the breathing tube. At the same time, directly behind the diffuser 3, at the installation site of the receiving element A, it will take place almost uniformly over the cross section of the velocity distribution diagram. Having passed the diffuser 3 and the installation location of the receiving element 4, the air flow enters the smoothly expanding channel of the confueor 1 of the breathing tube, which acts on the inhale as a diffuser, and then goes to the patient

To inhale to measure the velocity head associated with a known relationship with the flow rate of air in the breathing tube with a smoothly shaped diffuser 3, it is sufficient to measure the static pressure P directly behind the diffuser 3 in the plane of its coupling with the confuser 1 g of the breathing tube and compare it At atmospheric pressure P, this allows measuring the velocity head and the associated air flow in the breathing tube during inhalation, measuring the pressure in the pressure receiver 4 and comparing it with the atmospheric pressure.

When you exhale, the air flow through the device 2 for connecting the patient enters the flexible-prone confuser 1 breathing tube with low hydraulic resistance. In confuser 1, the air flow is accelerated, and the flow velocity distribution is equalized. Pass the installation location of the receiving element 4, the air flow through the diffuser 3 goes into the atmosphere.

In order to measure the output velocity associated with

 known dependence with air flow in the breathing tube with a diffuser 3, it is sufficient to measure the total pressure directly in front of the diffuser 3 in the plane of its interface with confuser 1 and compare it with atmospheric pressure. This makes it possible to measure the velocity head and the flow rate of air in the breathing tube on the exhalation associated with the NCSP, by measuring the pressure in the receiver element 4 and comparing it with the atmospheric pressure.

Thus, the proposed breathing tube allows to increase

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the validity of the study of multiple respiration due to the alignment and stabilization of the air flow in it, which is produced by its special profiling with a small internal volume (dead space) of the breathing tube. This reduces the impact on the result of the study of artifacts created with the dead space of the breathing tube.

F o rm ula invention

A pneumotachograph breathing tube containing an airflow laminariser, made in the form

Editor K. Voloshchuk

Compiled by F. Rogozhansky

Tehred l. Oleynik Proofreader A.Zimokosov

Order 305/3 Circulation 596 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., d.A / 5

Production and printing company, Uzhgorod, Projecto st., 4

confuser and diffuser, in the interface which are: installed receiving element of the air flow sensor

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different with

that, in order to reduce

by that

the influence of artifacts caused by the dead space effect, the profile of the confuser generatrix is made by arcs of two conjugate circles, with centers lying in the planes of the largest and smallest sections of the confuser, and the radii of the arcs of the circles forming the confuser are from 1.0 to 2.0 diameters of the smallest cross section of the confuser, and the ratio of the areas of its smallest and largest cross sections is from 0.64 to 0.25.

Claims (1)

Claim A breathing tube of a pneumotachograph containing a laminarizer of the air flow, made in the form of a confuser and a diffuser, in the interface of which there is a receiving element of the air flow sensor, characterized in 5 that, in order to reduce the influence of artifacts caused by the dead space effect, the profile of the generatrix of the confuser is made by arcs of two conjugate circles, with the centers lying in the planes of the largest and smallest sections of the confuser, and the radii of the arcs of the circles forming the confuser are from 1.0 to 2.0 smallest diameters 15 sections of the confuser, and the ratio of the areas of its smallest and largest sections is from 0.64 to 0.25.