SU1407839A1 - Mixer for spraying two-component highly reactive foamed polyurethane compositions - Google Patents

Abstract

The invention relates to the production of foams by spraying and casting, consisting of two components, foaming when mixed. The purpose of the invention is to intensify the mixing of the components by creating additional vortex flows. Components C and D are fed into the mixing chamber 4 of the mixing gun through channels 7 and 9, and air is fed through channel 8. Channels 7 and 9 are parallel to the axis of the mixing chamber 4. Channels 7 and 9 pass through the plug 6 and enter the mixing chamber camera 4 in the plane of its bottom. The outlet openings of these channels are diametrically opposite and lie adjacent to the side wall of the mixing chamber 4. The air supply channel 8 passes through the plug 6 and ends at the exit from it, intersecting with the through hole that is perpendicular to it steps at the ends and connected to the mixing chamber 4. The openings of the holes are made in the bottom of the mixing chamber at the points where channels 7 and 9 enter it, while those forming these holes intersect with the axes of the channels 7 and 9. 1 z.p "f-ly, 8 ill. (L

Description

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The invention relates to the production of foams by spraying and casting, consisting of two components, foaming during mixing, and can be used in various areas of the national economy to obtain thermal insulation,

The aim of the invention is to intensify the mixing of the components by creating additional vortex flows.

Figure 1 shows the gun-mixer, a general view; figure 2 is a view of And figure 1; Fig. 3-6 shows the assembly 1 in Fig. 2 (the position of the plug of the closure element when it is rotated at a certain angle in Fig. 7 is the housing of the spray gun, front view; in Fig. 8, section B-B in Fig. 7 .

The mixing gun includes a housing 1 in which a nozzle 2 with an interchangeable nozzle 3 is installed. The space between the housing 1 and the nozzle 2 forms a mixing chamber 4. In the housing 1, perpendicular to the axis of the mixing chamber 4, the locking element made in the form of a plug 6, In the body 1 of the gun parallel to the axis of its mixing chamber 4, channels 7–9 are arranged, located in a vertical plane, and the channels

7 and 9 serve for the supply of components

8 and G in the mixing chamber 4, and the channel 8 - for the supply of air into it. The channels 7 and 9 pass through the plug 6 and enter the mixing chamber 4 through its bottom. The outlet openings of the channels 7 and 9 are diametrically opposed and matched with the circumference of the mixing chamber 4. The channel 8 passes through the plug 6 and ends at the exit from it. A stopper groove is made in the plug 6 at the exit point of the air inlet channel 8, whose width is equal to the diameter of the opening of the air inlet channel 8, and its cross section is at least 0.75 of the cross section of the air inlet channel 8.

In channels 7 and 9, fittings 10 to 12, respectively, are installed, to which hoses 13 to 15 are connected, respectively, which serve to supply the components C and D of polyurethane foam and air.

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A hollow handle 16 is attached to the body 1 of the pistol, made, for example, from plastic.

At the exit of the plug 6, the air inlet channel 8 intersects with an opening 17, which is made with threaded steps at the ends in which plugs 18 are installed.

0, the aperture 17 is made with a diameter equal to the diameter of the air passage 8. In the places where the steps pass, the aperture 17 is made apertures 19 and 20 connecting the aperture 17

5 mixing chamber 4.

Holes 19 and 20 are made at an acute angle about the bottom of the mixing chamber 4 and an acute angle p, to the radii of the circle on which

0 centers of the outlet openings of channels 7 and 9 for the supply of components. Forming holes 19 and 20 intersect with the axes of channels 7 and 9 in the plane of the bottom of the mixing chamber 4.

5 The optimal angles of i- ft at vy-. The openings 19 and 20 are angles 32 ° - 3 ° and - 28 °.

To prevent ejection of the nozzle 2 during operation, it is fixed by a nut 21.

The bottom of the mixing chamber 4 is made convex to prevent the cone from forming the foam composition with frequent stops during the operation of the gun. The convexity of the bottom of the mixing chamber 4 is directed towards the orifice of the nozzle 2. The convexity contains grooves .22 of variable cross section, tapering in the direction opposite to the direction of the air inlets 19 and 20.

Gun-mixer works as follows.

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In the initial position, the plug 6 is in the closed position (FIG. 3). At the same time, the stopper 6 blocks the channels 7 and 9 for the supply of components, and the ca-. The air inlet 8 is disconnected from the through-hole 17. Thus, the supply of components and air to the mixing chamber 4 is shut off,

Before starting work, turn the handle 5 to turn the plug 6 on 45 ° to the left to the “Open” position (figure 4). 55 Liquid components C and D are pumped through hoses 13 and 15 through fittings 10 and 12 through channels 7 and 9 c. mixing chamber 4 with simultaneous

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air supply through the hose 14 through the fitting 11 through the channel 8.

When the crpyi, the components and the air in the mixing chamber / 4 collide, an air-liquid mixture is formed, which spirals towards the center of the chamber due to the described embodiment of air inlets 19 and 20 and entering the nozzle 2.

At the same time, due to the large areas of the 0-shaped outlets of the openings 19 and 20, in the flow of the air-liquid mixture itself, additional eddies appear, moving in a spiral 15 around the axis of the flow itself. This is due to the fact that the air, breaking out of the holes, increases dramatically in volume and, meeting with the movement of the flow of the mixed components, restrains it and, transferring to it a part of its energy, creates additional vortices in it.

As a result of the addition of these two movements, the air-liquid flow receives a complex movement, due to which the intensity of the mixing of the components in the flow increases.

Spinning, the streams are mixed, and when passing into the gap between the flash and the convexity of the bottom of the mixing chamber 4, the mixture partially changes the rotational suppression due to the presence of the anvans 22 on the convexity. Due to this, additional vortices appear in the flow of the mixed components in the cavity of the nozzle 2.

Spraying of the mixture occurs after it leaves the nozzle 3 due to a sharp expansion of air.

After spraying the handle

5 turn the plug 6 on 105 to the right (FIG. 5) or to the left (FIG. 6) to the floor. Purge. In this position, the tube 6 overlaps channels 7 and 9.

Thereby shut off the supply of components and purge the system with air, resulting in a cleaning of the mixing chamber 4 and the nozzle 2 from the remnants of the mixture. After 20-30 with a cork

6 is turned to the Closed position (FIG. 3).

During the operation of the proposed cone outgrowth mixer gun with short-term stockpiles in the mixing chamber, it does not appear.

The implementation in the device of the intersection of the forming air jets with the centers of the jets of the components in the plane g

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Types of the mixing chamber, as well as air supply to the mixing chamber at acute angles to the plane of the bottom of the mixing chamber and the radii of the circle on which the centers of the component jets are located, intensify the mixing of components and obtain a uniform foam structure of polyurethane foams, because -; in addition to the main movement in a spiral, an additional vortex flow is formed, which is directed in a spiral around the axis of the flow itself.

Claims (2)

1. A mixing gun for spraying two-component highly reactive polyurethane foam compositions comprising a housing forming a mixing chamber with channels for introducing components arranged parallel to the chamber axis, the outlet openings of which are diametrically opposite to the bottom of the mixing chamber and mated with its lateral surface, as well as with channels for the introduction of compressed air arranged in parallel planes and connected through the distributing system with the air supply channel, the locking device is made-, A tube installed in front of the mixing chamber perpendicular to the channels for entering components , the compressed air inlets are arranged intersecting with the channels for introducing the components in the plane of the bottom of the mixing chamber, and the compressed air supply channel is placed between the channels for introducing the components and connected through the stopper to the exhaust system, the stopper having a stepped groove, whose width is equal to the diameter of the compressed air supply channel. 2. The mixer gun according to claim 1, characterized in that the bottom of the mixing chamber is made convex R 51ch078; 396 the direction of the nozzle with canaries is retracted in the opposite to the channels for the variable section, narrowing of which is directed by the compressed air. 21 I turned 5 fig.Z InoSepny / no FIG. five 76 FIG. 2 I f7oSepfft / mo FIG. I f7oSep {// 77O fig gz 20 FIG. at