SU827028A1 - Device for measuring parameters of breathing - Google Patents

Description

one

The invention relates to medical technology, namely to devices for pulmonary research, and to be used to measure parameters of pulmonary ventilation and temporary parameters of respiration in various conditions of human activity.

A device for measuring breathing parameters is known, which contains a mask with inhalation and exhalation valves, a restrictive chamber with a lattice airflow laminator, a capsule with through-holes containing a thermal sensor thread, and a protective screen in the form of a reflector mounted on the outer side of the restrictive chamber 1J.

A disadvantage of the known device is the absence in its output signal of information on the amount of inhaled air. In addition, the result of measuring the volume of exhaled air of sushi depends essentially on the non-linearity of the characteristic of the thermal sensor, its inertia and the temperature of the surrounding medium.

The aim of the invention is to improve the accuracy of measuring the volume of inhaled and exhaled air.

The goal is achieved by the fact that a second thermal sensor and a second air flow laminator are inserted into the restrictive chamber of the device, while the thermal sensors are spaced apart along the axis of the chamber and located between the laminators that are installed at its inlet and outlet.

In addition, the temperature sensors are made in the form of thermistors.

FIG. 1 shows schematically a device for measuring respiratory parameters; FIG. 2 and 3 - timing charts of the device.

The device contains a respiratory mask 1, to which the restrictive chamber 2 is attached in the form of a tube for communicating the subject with the atmosphere. Inside the limiting chamber, two inlet and outlet laminates 3 and 4 are installed at its inlet and outlet, which serve to create a flow of air during entry and expiration that is uniform over the cross section of this chamber. Thermal sensors 5 and 6 are installed inside the limiting chamber 2 between the laminators 3 and 4 and are spaced apart by the distance / i of the chamber axis.

Thermocouples 5 and 6 used the same highly sensitive thermistors.

Claims (2)

The device works in the following way. In the initial state, the thermal sensors 5 and 6 have a temperature t C (the average value between the ambient temperature t C and the temperature of the exhaled air / 2 C). When you exhale, the air from the lungs passes through the mask 1, the laminator 3 and the chamber 2 and at the time point i begins to heat the thermal sensor 5 to temperature (solid curve in Fig. 2). Through time, the heat front of the exhaled flow passes the distance / and begins to heat the temperature sensor 6 to a temperature t2 C (dotted curve in Fig. 2) and then through the laminator 4 the exhaled air enters the atmosphere. If after expiration of an exhalation at the moment of time s there is a science between respiratory cycles, then both thermal sensors are cooled to the initial temperature. During inhalation, air from the atmosphere through the laminator 4 is sucked into chamber 2 and at time t cools the temperature sensor 6 to temperature tl C, and after a time the temperature sensor 5 cools down to temperature iC and enters the lungs through the laminator 3. If the inhalation and exhalation follow each other continuously, then the A / pause section 4–3, equal to the pause time between inhalation and exhalation, is absent and the time diagram has the form shown in FIG. 3. The presence of time intervals in the output signal of the sensor (Fig. 2): - expiration time - inspiration time, - time of thermal flow front propagation for distance / during expiration - thermal penetration time / during inspiratory allows to calculate tidal volumes when you inhale and exhale: VL-- Wed-vdd - Ibr. out) where UVD is the FULL volume of inhaled air; LOST, - the full volume of exhaled air; average linear velocity. air - air flow velocity in the restrictive chamber when inhaling; average linear CD. vul - air flow in the restriction chamber during expiration; S is the cross section of the restrictive chamber; / - spacing between temperature sensors. Introducing a second thermal sensor into the device allows one to produce an output signal proportional to the volume of inhaled and exhaled air. The output signal of the sensor is a function of time and does not depend on the type and degree of nonlinearity of the characteristics of the thermal sensors, the temperature of the exhaled air and the environment. This allows the use of highly sensitive thermistors as thermal sensors. The inertia of thermal sensors, influencing the rate of change of their temperature (angles tti and css in Fig. 3), does not introduce a significant error in determining A, as for thermal sensors of the same type. Thus, the design of the device makes it possible to increase the accuracy of measuring the volume of inhaled and exhaled air, which expands the area of use of the device. Claim 1. A device for measuring breathing parameters, comprising a breathing mask with a restriction chamber attached to it, inside which an air flow laminator and a thermal sensor are located, characterized in that, in order to improve the accuracy of measuring the volume of inhaled and exhaled air, a second a thermal sensor and a second air flow laminator, wherein the thermal sensors are spaced apart along the axis of the chamber and located between the laminators that are installed at its inlet and outlet. 2. Device io p. 1, characterized in that the temperature sensors are made in the form of thermistors. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 386622, cl. A 61B 5/08, 1971. CXJb  Nxx