The subject of the invention is a pipe con nection of the air duct port with an insulation lagging wal l i n a ventilation or an air conditioning system, where at least one of the parts: the port or the laggi ng is made of flexible plastic. The insu lation lagging can, for example, cover fan or air conditioni ng units, recuperators, sterilizers, flow dividers.

There are known part con nectors made of foamed plastic, where the port along the sleeve section extending from the lagging wal l has a diameter equal to the inside diameter of the air duct, while at the other end it has a flange with which it is pressed into the wal l opening and is abutted axial ly against the shou lder of the opening in the wal l. Such a solution is presented, among others, in the patent description no. KR101294247 of a fan u nit insu lation lagging with air duct ports. I n the EP1959208 description pertaining to the air divider with a chamber made of foamed polypropylene, the air supplied by a line th rough the port to the divider chamber flows to several branches through lines connected to the cham ber wal ls. There are also known, for exam ple from the PL152861 description, plastic l ine connectors, where the wave shape of the connected lines is used.

The pu rpose this invention is to develop a pipe connection port with an insulation laggi ng wal l, made of plastic, which wi l l provide rigid and tight positive fit detachable connection taking advantage of the elasticity of materials.

Similar to known solutions, the connection according to the invention has a port with a section of an external sleeve with the diameter equal to the internal diameter of the air duct, while at the other end it has a flange which is press-fitted with the circu mferential su rface and abutted against the shou lder in the opening of the wal l with a com plementary profile. The essence of the solution according to the invention consists in the fact that the port, on the side su rface of the flange has at least one wave-shaped bu lge with the largest height enabling pressing the port into the shou lder of the opening withi n the range of elastic deflection of material, and axial ly behind the flange it has a sleeve section, which is con nected with a slight press-fit in the inner opening of the shou lder. I n the corner of the front face of the flange, a groove is made with a semi-circu lar profile, in which the O-type sealing ri ng is embedded.

It is preferable that, while maintaini ng the similarity of shape, the dimensions of the bu lge on the port and the lagging wal l are differentiated so that, in com bination, they form a loose fit with gaps on fragments of the front su rface of the bulge and the front su rface of the flange, and a press fit on the rear surface of the bulge with tolerances within the range of the elastic deflection of the material.

The bu lge wave is of a height within the range of 2 to 5% of the outer diameter of the flange.

It is also preferable when the port on the outer sleeve has at least two axial ly spaced flat retaining rings with an outer diameter by 2 to 4% greater and whose faces are bevel led or have a radial profile.

Wave-like geometry of the bu lge with selected fits of elastical ly deformable materials generates compressive stresses, which ensure strong and rigid connection of the port with the lagging wal l and at the same time permanent pressure of the gasket against the shoulder.

The pipe con nection according to the invention is explai ned with a description of an em bodiment shown in the figu res, where Fig. 1 shows an axial cross section of the connection, Fig. 2 - a front half-view of the port and Fig. 3 - an en larged view of a part of the con nection cross section.

Port 1 is seated in wal l 2 of the fan unit i nsu lation lagging, both connected parts are made of foamed polypropylene with a closed cel l structure. Port 1, along the section extending from wal l 2 has an external sleeve 1.1 with diameter dz equal to the internal diameter of air pipe 4. At the other end it has a flange 1.2 which on the side surface has a wave-like bu lge 1.3 of height h from 2 to 5% of the outer diameter dzl of flange 1.2. Flange 1.2 is pressed into the opening of wal l 2 and its front face is abutted against shou lder 2.1 in the wal l 2 opening. Axial ly behind flange 1.2 port 1 has a sleeve section 1.4 which is lightly press-fitted i n the internal opening of shoulder 2.1. I n the corner of the front face of flange 1.2, a groove 1.5 is made with a semi-circular profile, in which an O-type sealing ring 3 is embedded. The width of the flange 1.2 and the sleeve section 1.4 is less than the width of the wal l 2. Port 1 on the outer sleeve 1.1 has two retaining rings 1.6 spaced apart axial ly, with the outer diameter dz2 lager by 2 to 4% than the internal diameter dz of the air duct 4. The front faces of retaining rings 1.6 have a radial profile which makes it easier to attach the air duct 4.

The dimensions of bulge 1.3 on port 1 and wal l 2 of the lagging are differentiated so that while maintai ning the shape similarity in com bination they cause the occurrence of an axial force pressing the seali ng ring 3 against the shoulder 2.1. Loose fits with gaps yl, y2 are present on sections of the front face 2.2 of bulge 1.3 and front face of flange 1.2, and the press fit z on the back surface 2.4 of bu lge 1.3, within the tolerances in the range of elastic deflection of the material.

List of designations in the figure

1. Port

1.1. outer sleeve

1.2. flange

1.3. bulge

1.4. sleeve section

1.5. groove

1.6. retaining ring

2. I nsulation lagging wall

2.1. shoulder

2.2. wall section with a loose fit

2.3. wall section with a loose fit

2.4. wall section with a press fit

3. O-type sealing ring

4. Air duct dz. external sleeve diameter

h. bulge wave height

dzl. flange outer diameter

dz2. retaining ring outer diameter

yl. loose fit gap

y2. loose fit gap

z. fit