PL180786B1 - Pneumotahographic head - Google Patents

Abstract

The invention solves the problem of elimination of rigid dams in the air flow duct and makes the measurement conditions more natural. A pneumotachograph comprises an external tube (1) having a first, bigger diameter, and on the inside thereof at least one internal tube (2) of smaller diameter situated preferably concentrically with the external tube (1). The external tube (1) of bigger diameter is shorter than the latter (1) tube whereas the orifice of the external tube (1) of bigger diameter has a closure (A) between its edge and the internal tube (2) of smaller diameter so that the air flow duct is the internal tube (2) of smaller diameter. At least one measuring orifice (B) is situated within the measuring area comprising the external wall of the tube (2) of smaller diameter, the internal wall of the closure (A) of the tube (1) of bigger diameter, the internal wall of the tube (1) of bigger diameter and the space confined within the mentioned walls.

Description

The subject of the invention is a pneumotachograph tube for testing the flow velocity and volume of the flowing air, in particular for the assessment of respiratory system function.

A pneumotach tube is known from the utility model description No. Ru 56 734, which consists of two funnel members joined by faces of larger diameter and defining an air flow channel, and containing a mesh-shaped abutment at the joint of the fronts. The tube is also equipped with connectors on both sides of the partition, intended for mounting the air ducts connecting the tube with the measuring system. Both funnel members have the same shape of the socket section, differing in the length of the tubular section, and each member has a circumferential groove at the contact face of the socket section. A ring with an axial length not greater than the sum of the depths of both grooves is pressed into the groove between the faces. The net placed between the faces is unframed, it is clamped between the bottom of one of the grooves and the face of the ring, and it is stretched by the pressure of the ring. The stub pipes leading out of the contact zone of both front faces are located parallel and concurrently to each other, while the longitudinal axes of the longer stub channels are parallel to the contact plane of the fronts. The openings of the shorter channels of stub pipes, the axes of which are perpendicular to the contact plane of the fronts, are situated at a distance not greater than one-fourth of the diameter segment of the socket segment of the member at its widest point.

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A device for measuring the parameters of a flowing gas is known from the patent description US 4 372 170, in which the outer tube with a larger diameter contains inside a tube with a smaller diameter arranged concentrically. The section of the inner tube located inside the larger diameter tube is shorter than it. The test port is located in the area between the outer surface of the smaller diameter tube and the inner surface of the larger diameter tube.

The essence of the solution according to the invention consists in the fact that the opening of the outer tube with a larger diameter between its edge and the inner tube with a smaller diameter has a closure, the air flow channel is an inner tube with a smaller diameter, and at least one measurement opening is located in the measurement area including the outer wall. smaller diameter tubes, the inner closure wall of the larger diameter tube, the inner wall of the larger diameter tube and the space bounded by said walls. The face of the inner tube is flush with the closure of the face of the outer tube. The closure may be integral or detachable. The outer tube together with the inner tube may constitute a module assembled with the ends of the tubes with an analogous symmetrical module or an asymmetrical module. Preferably, the outer tube has a socket with a portion tapering on the closure side of the tube. The inner tube has a shaped edge, preferably cut at an angle to the tube axis.

The advantage of the solution according to the invention is the simplicity of construction. The modular repeatability of the tube structure allows it to be assembled into assemblies that enable various measurements to be made. Thanks to the elimination of a continuous partition, the resistance of the flowing air has been minimized, which results in measurement conditions similar to natural ones. The tube can be used as personal equipment for the patient or it can be a single-use item.

The solution according to the invention is shown in the exemplary embodiments in the drawing, in which Fig. 1 shows the tube in a longitudinal section with a partial side view, Fig. 2 - a variant of the tube with a different location of the stub, Fig. 3 - two tube modules put together at their ends, Fig. 4 the variant with the funnel member in the variant with the tube extended beyond the front of the funnel and in the variant with the tube ending flush with the front of the funnel, Fig. 5 - variant with the funnel members aligned with their faces.

The pneumotach tube is an outer tube 1 of larger diameter containing an inner tube 2 of smaller diameter arranged concentrically. The inner tube 2 has a diameter ranging from 10% to 99% of the outer diameter of the tube 1.

The inner section of the tube 2 located inside the outer tube 1 is shorter than the outer tube 1. The opening of the outer tube 1 between the edge of its face and the inner tube 2 has a closure A, so that the air flow channel is the inner tube 2.

Closure A can be fitted integrally or releasably as a separate part. The inner tube 2 has a shaped face edge situated inside the outer tube 1, preferably cut at an angle with respect to the tube axis.

The measuring openings B are located in the measuring area comprising the outer wall of the tube 2 with a smaller diameter, the inner wall of the closure A of the larger diameter pipe 1, the inner wall of the larger diameter pipe 1 and the space limited by said walls.

The measuring openings are connected with stub pipes 3. The stub pipes 3 can be located along the pipe axis or perpendicular to it. Measurement openings B can also be the end of probes situated in said measurement area. The face of the inner tube 2 is flush with the closure A of the face of the outer tube 1.

In an embodiment, the inner tube 2 may protrude beyond the closed face of the outer tube 1.

In another embodiment, the outer tube 1 together with the inner tube 2 constitute a tube-end module with an analogous symmetrical module. An unsymmetrical variant is also possible.

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In a further embodiment, the outer pipe 1 has a socket C with a portion tapering on the closure side A of the pipe. Various variants of this embodiment are possible. The inner tube 2 may have a face flush with the socket closure or it may extend beyond the closure protruding outwardly from the outer tube 1. The two socket members may be face-to-face, in a symmetrical and asymmetrical variant. With this combination, the connecting element may be a ring 4.

In all exemplary embodiments, the measurement area may be divided by walls defining measurement fields, preferably located along the axis of the pipes 1, 2. The measurement area may also have additional openings. The inner tube 2 of smaller diameter may be a conduit in a bundle of tubes.

During use, the ends of the air conduits are put on the stubs 3, connecting the tube with the measuring system. During the examination, the patient holds the tube by the gripping part with his hand and blows or breathes through the tube through the mouthpiece.

The tube can also be used for non-medical purposes, for example for measuring air flow in ventilation systems, for aerodynamic studies and other studies related to the measurement of gas velocity and volume.

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Publishing Department of the UP RP. Circulation of 60 copies

Price PLN 2.00.

Claims (7)

Patent claims 1. A pneumotach tube for testing the flow velocity and volume of airflow, especially for the assessment of respiratory function, which is formed by an outer tube with a larger diameter, having an inner tube of a smaller diameter located concentrically, with a section of the inner tube with a smaller diameter located inside the outer tube of the larger diameter is shorter than it, characterized in that the opening of the outer tube (1) with a larger diameter between its edge and the inner tube (2) of smaller diameter has a closure (A), the air flow channel is formed by an inner tube (2) with a smaller diameter diameter, and at least one measurement opening (B) is located in the measurement area including the outer wall of the smaller diameter tube (2), the inner wall of the larger diameter tube (1), the larger diameter of the inner wall of the tube (1) and the space bounded by said walls. 2. Tube according to claim A device as claimed in claim 1, characterized in that the end face of the inner tube (2) is flush with the closure (A) of the end face of the outer tube (1). 3. Tube according to claim 2. The device of claim 2, characterized in that the closure (A) is releasably fitted. 4. Tube according to claim 1 3. The pipe according to claim 3, characterized in that the outer tube (1) together with the inner tube (2) constitute a tube-end module with an analogous symmetrical module. 5. Tube according to claim 1 3. The tube according to claim 3, characterized in that the outer tube (1) together with the inner tube (2) constitute a face-to-face module with an analogous unsymmetrical module. 6. Tube according to claim 3. A method according to any of the preceding claims, characterized in that the outer tube (1) has a socket (C) with a portion tapering on the closure side (A) of said tube. 7. Tube according to claim 1 6. The tube according to claim 6, characterized in that the inner tube (2) has a shaped edge, preferably cut at an angle with respect to the tube axis. * * *