FR2573328A1 - Device for injecting a loose fibrous or granulated product into a cavity - Google Patents

Abstract

The invention relates to a device enabling a loose fibrous or granulated product to be injected into a cavity so as to improve the thermal or acoustic insulation performance thereof as well as to improve the mechanical characteristics thereof. The device includes an inlet for the loose product and for pressurised air via a transparent hose 14 connected to a quick-release coupler 8. A cone 1 reduces the diameter of the transport hose to the diameter of the injection orifice 16. Helical blades 6 in this cone impart a rotary movement to the product. This movement is accelerated by a tangential air inlet 18. A valve 9 enables the gun to open. In order to prevent blocking, the product returns to the machine via an orifice 2 made in the gun connected to a return hose 3 and a compressed-air inlet 18 expels the plug. The jet of air and loose product will be oriented parallel to the plane of the cavity by a deflector 4 which includes orifices 5 via which an air jet will orient the product. It will be possible to saturate the deflection air with an adhesive mist introduced into the compressed-air circuit via a venturi nozzle 12 sucking in the adhesive. A manual or remote-controlled valve adjusts the intake of compressed air. The device according to the invention is particularly intended for thermal or acoustic insulation and for enhancing the mechanical characteristics of hollow cavity walls by pneumatic injection of a loose fibrous or granulated insulation until it is filled.

Description

 The present invention relates to a device making it possible to inject a fibrous or granulated product in bulk into a cavity, for example to improve the thermal or sound insulation characteristics as well as the mechanical characteristics.

 Until the beginning of the oil crisis, that is to say around 1975, most of the buildings were constructed using the technique of double hollow walls. An air space was left between the exterior wall and the interior wall. This technique has the advantage of constituting healthy and dry walls thanks to the air layer which eliminates any risk of moisture transmission from the exterior wall to the interior wall by providing air circulation.

 Unfortunately, these walls are not insulating. To correct this defect and to isolate this type of building, we have so far tried to use a certain number of products: synthetic foams (urea formaldehyde resin, phenolic resin, polyurethane resin ...) are difficult to apply. work, cause the walls to swell, are hydrophilic.

 We have tried to fill these cavities with powdery bulk products such as vermiculite, granules of cellular insulators, glass or expanded clay beads, expanded polystyrene beads, etc. These bulk products have the drawback of do not have mechanical strength in the wall and flow down or empty through the slightest opening.

 Some attempts have been made to fill these cavities by injecting loose mineral wool into them, but without much success.

 In fact, the machines available on the market did not make it possible to obtain complete filling with the certainty of not leaving large pockets without having to create too many injection orifices. The techniques, in their current state, also do not prevent the packing of the mineral fibers injected in bulk.

 The machines for processing mineral wool are now well known. They are widely used for the projection of a fibrous insulator with simultaneous bonding. This is how we flock the undersides of high floors and ceilings, cellar, crawl spaces, etc. These machines are also used for insulating lost roof spaces by spreading with a pneumatic machine d '' loose insulation.

 There are two types of machines.

 10 a simple fan: a paddle wheel is driven at high speed. It causes an aspiration of air by which the insulator is introduced which is thus, on the one hand, ground, on the other hand, mixed with the flow of carrier air. A pipe transports the "air-insulating" mixture to the attic.

20 the second type of more elaborate machine comprises a storage tank in which the bags of loose insulation are emptied, a system for demoding the blocks, a feeding system, generally an Archimedes screw which opens into a card with rotary fingers . The wool thus transported is opened, arrives at the entrance of a rotary lock which intro
feeds alr by a booster

duit in the pneumatic circuit / These machines are now well known and widely used. However, they do not allow a simple, safe, economical way to inject mineral fibers or other insulators in bulk in the hollow walls or in the other cavities to be filled.

It is indeed observed that if the filling of the beginning of the cavity is possible by drilling a hole of large diameter, generally 60 to 100 mm, very quickly the piping clogs unpredictably and one obtains a filling of the cavity quite made random and always irregular.

 The present invention makes it possible to remedy these defects. It therefore relates to an injection gun adaptable to machines of all types. This pistol, object of the present invention, comprises the following elements.

 A cone (1) reduces the diameter of the hose to allow the wool to be injected into the cavity through a small injection hole (16).

 To avoid constant and unpredictable blockages, an orifice (2) is provided at the almost end of this cone) t is connected to this orifice, a return pipe (3) of suitable diameter. As soon as the injection into the wall begins to meet some resistance, the pressure increases and the flow of wool which can no longer enter directly into the wall is deflected through the orifice (2) formed and goes into the return pipe (3 ) to the machine.

 A close observation of the path of the wool flakes shows that they violently strike the wall of the interior of the wall and then move perpendicular to the cavity.

 All the kinetic energy of the particles is absorbed in the shock which they undergo when they leave the orifice (16) to enter the wall. All the kinetic energy lost could be usefully used to ensure better filling and effective packing of the insulation.

 In order to avoid this defect and to facilitate the change of direction, there is opposite the injection nozzle (16) which extends the cone (1) a jet deflector (4) composed of a cone in which one can make holes (5). Through these orifices (5) a jet of compressed air will emerge which will push the insulation in a direction perpendicular to the direction of arrival and parallel to the plane of the cavity.

 A propeller (6) arranged in the injection pipe will give the flow a rotary movement facilitating its ejection by centrifugal force.

 In order to avoid the risks of a possible blockage by the arrival of an insulator while the cavity is filled, a pressure switch will be placed on the machine. This will instantly stop the supply of granules or fibers to the piping as soon as the back pressure reaches the determined value. The pressure tap of this pressure switch will be done either on the machine at the outlet of the booster, or by a pipe (17) located either close to the injection pipe (16) or just before the discharge port (2) .

Thus, as soon as the cavity is filled, an air back pressure will appear in the orifice (17). This back pressure will stop the supply of bulk material. The little insulation that will still remain in the piping will be deflected in the return pipe (3) and returned to the machine which
principa e will avoid clogging of the piping /. In order to avoid the exaggerated losses of air which could leak by the orifice (2), one will dispose inside the gun a cone (7) which will behave like a venturi. This venturi will remove unwanted air loss.

 To facilitate the use of this gun, all connections will be made by means of quick couplings (8) allowing immediate disassembly and reassembly.

 A closing valve (9) controlled by a lever (10) will stop sending wool and close the orifice as soon as the cavity is full.

This closing is indeed essential when working in an occupied apartment so as to avoid the projection of insulators which would soil the housing.

 The inlet into the cone (1) as well as the outlet (2) of the discharge orifice will be connected to their respective piping by transparent pipes (14).

 The air deflector orifices (5) (4) are supplied with air by a pipe (11).

The pipe (11) is connected to the outlet of a venturi (12). The compressed air passing through this venturi nozzle causes a vacuum in an orifice (13) which is connected to a pipe. The depression found in this pipe is used to suck up an adhesive which will be used to glue the wool
or other loose insulation so as to avoid settling over time.

The rotary movement created by the helical blades (6) could be
accelerated and increased by a tangential compressed air supply (18)
During the tests carried out, it was noted that this additional air intake
(18) was particularly useful for ensuring the unblocking of the pistol.

 The figure shows a section of the device according to the invention and will allow a better understanding of its operation. It is therefore a question of filling a cavity with a small hole, of packing the material which is injected, of possibly dispersing an adhesive therein to ensure good mechanical strength, while avoiding clogging the piping when the cavity is full.

 The object of the present invention gun is therefore connected to the machine by three pipes.

 A first pipe ensuring the supply of bulk insulation and air carrying the low pressure insulation, this pipe is generally of a diameter of 40 to 80 mm. For the realization of the present invention the dimension 50 mm (2 inches) has proved to be particularly interesting.

 A second pipe allows the return to the machine. This piping is advantageously with a diameter between 15 and 40 mm, a diameter which is determined by the length of return piping, the diameter of the granules which it is desired to inject into the wall.

 A third pipe brings compressed air.

 Optionally a fourth pipe is connected to the gun to indicate to a pressure switch, mounted on the machine, the pressure prevailing in the gun.

Another pipe is connected to the orifice (13) and joins a container of glue
The machine is started and delivers a mixture of low pressure air and wool diluted in the air. This mixture arrives at the gun by a large diameter pipe which will preferably be transparent in the last part.

 In order to be able to quickly assemble and disassemble the pistol, it is advantageous to connect the transparent hose (14) to a quick connector, of the fire engine, Guillemin connector type or any other figured quick connector system (in (8)).

 The air and mineral wool flow is introduced into the large diameter of the gun, about 50 mm, and meets helical blades (6) which put the wool in rotation.

The wool flow then enters a cone which reduces the passage diameter and therefore increases the speed of the flow. down to the smallest diameter
of this cone (7).

 At the height of the smallest part of the cone (7), an orifice (2) is formed with a diameter of 15 to 40 mm, but generally around 30 mm.

After reducing the diameter of the cone (7), a flaring is caused to constitute a sort of venturi
At the passage (7), there is a slight depression in the tube (2). The flow expands after one nozzle (7), passes through a valve (9), controlled by an open lever (10). A new conical part forces the flow of insulation and air to reach a nozzle (16) which will serve as an injection orifice in the cavity. This nozzle (16) will have a diameter between 10 and 50 mm depending on the flow rate and the material available.

 Generally the optimum dimension is between 15 and 30 mm.

 When the valve (9) is open, the mineral wool crosses it and passes through the nozzle (16) inside which new helical blades (6) have been placed.

 The flow of insulation and air then meets the jet deflector (4).

This jet deflector will consist of a cone and made of steel resistant to abrasion. The flow of insulation and air will thus be deflected perpendicularly and, while conserving its energy, so that it can be projected further inside the cavity, avoiding losing kinetic energy by direct impact against the wall facing the nozzle (16).

 This jet deflector (4) can be supplied with compressed air by a pipe (11) with an internal diameter of 2 to 6 mm.

 This deflector will also include orifices (5), formed in the periphery of the cone at the bottom. By these orifices (5), a jet of compressed air will be released, which coming to meet the jet leaving through the nozzle (16) will communicate to the insulating granules an additional kinetic energy allowing them to be projected further, while ensuring better compaction of the insulation in the wall.

 The orifices (5) can be either fixed, or made up of small nozzles, such as Solex nozzles allowing the exact flow rate to be adjusted.

 The deflector (4) may be made of steel or any material which is particularly resistant to abrasion.

 This deflector (4) will be manufactured without major difficulty by machining an outer cone and an inner cone into which the pipe (11) will open.

 This internal cone will be filled either with a screwed disc, or with a disc glued or fixed by a circlip or by any other means available to those skilled in the art.

Thus the wool or loose insulation arrives through the nozzle (16), the
blades (6) imparted a rotational movement to it. The centrifugal force will already communicate to the insulator a tendency to take a direction parallel to the plane of the cavity. The mechanical deflector (4) will increase this tendency which will be further developed by the jets of pressurized air supplied by the pipe (11) and exiting through the orifices (5).

 As the air and insulation flow, the cavity fills until the back pressure encountered in the piping (3), connected to the gun at (2), is less than the counter pressure presented by the introduction of the insulation into the wall at the outlet of the orifice (16).

At this time, there are several possibilities 10 / The operator notes that the insulator pushes back in the piping (3), through the transparent part (read), it is enough for him to close the valve (9), maneuvered by the lever (10). The nozzle (16) being closed, no more product leaves it. The operator removes the injection pipe and goes to another hole in the wall. bar'
As soon as the nozzle (16) has been reintroduced into the new orifice, the operator reopens the valve (9) by operating the lever (10). Immediately, the flow of air and insulation meets a free orifice and the exit being easier by the nozzle (16) than by the exit (2), the flow of insulation will go in a preferential way in the wall.

25
It has been found that closing the valve (9) and forcing all the material to return to the machine or to be discharged through the orifice (2) has a drawback. To avoid this drawback, the present invention also claims the idea of carrying out a measurement of the internal pressure of the piping. This pressure can be measured either at the outlet of the air generator under low pressure from the machine, or rather by a nozzle (17) mounted on the gun.

 As soon as the insulation ejected from the nozzle (16) has almost filled the cavity, the pressure increases in the gun at the level of the cone (1) and the reduction (7).

 This increase in pressure causes the wool to flow back through the orifice (2) and return to the ~ piping (3). To prevent the machine from continuing to supply the piping with product, it suffices that the pressure switch, informed of the overpressure, by the taps (17) stops the machine feeding. The pressure switch will therefore control a relay which will instantly stop the supply system by isolating from the machine such as screws, card, lock, etc.

 Thus will be discharged through the orifice (2! And the pipe (3) that the material remaining in the piping. However, this material is generally sufficient to ensure perfect filling of the cavity.

The discharge port (2) was placed after a venturi nozzle
Indeed, we know that a venturi nozzle causes a depression.
The purpose of this venturi nozzle is to prevent the piping from blowing air excessively during the filling operation where the air is fully useful.

 To also avoid the exaggerated return, in normal operation, of the product through the orifice (2) opening into the pipe (3), it is possible to mount, on this pipe (3), a calibrated valve which will increase the overpressure and will avoid parasitic leaks. This calibrated valve will open as soon as the back pressure encountered at the outlet of the nozzle (16) is sufficient.

 To be sure that the insulation is perfectly packed and mechanically solid in the wall, or in the cavity, it seemed interesting to be able to glue it. For this, the spray gun object of the present invention may include an inlet of glue added to the inlet of pressurized air.

 The introduction of glue into the compressed air emerging through the orifices (5) and supplied by the pipe (11) can be carried out by any means, such as a pump, a pressure pot, etc. However, it seems advantageous placing a venturi nozzle (12) on the pipe (11). This venturi nozzle will cause the passage of compressed air, the suction of the glue through the orifice (13), itself connected to the glue tank.

The passage of compressed air through the nozzle (12) causes the suction of the adhesive, which is then diffused into the heart of the material through the orifices (5).

 A mechanical or remote-controlled valve (15) will ensure the synchronization of the air intake and the injection of insulation into the walls.

 The device according to the invention is particularly intended for the thermal insulation of old or new buildings by filling walls with double partitions. It can also be used whenever it is desired to inject a fibrous product or a granulated product or in flakes of light or heavy material into a cavity to ensure its filling.

This gun is particularly suitable for the thermal insulation of
vertical walls, cavities between the ceiling tops and the
under parquet floors, all cavities needing to be
insulated, such as water heaters, solar collectors, heating pipes,
cooling piping. In summary, whenever we need to rem
fold a cavity with a bulk product.

Claims (1)

l) Device for injecting a granulated or fibrous product in bulk into a cavity characterized in that it comprises a cone (1) reducing the diameter up to an injection nozzle (16) of a smaller diameter and than an orifice (2), connected to a return pipe (3) has been formed in the cone so as to ensure the discharge or the return of the product when the cavity to be filled is full.  2) Device according to claim nD1 characterized in that a valve (9) operated by a lever (10) allows to stop the arrival of the product.  3) Device according to one of the preceding claims, characterized in that a jet deflector (4) is arranged opposite the nozzle (16) and that this jet deflector (4) may include an inlet for compressed air. evacuated by nozzles (5). The purpose of compressed air is to facilitate deflection of the jet.  4) Device according to one of the preceding claims characterized in that a venturi nozzle has been provided before the orifice (2) of discharge.  5) Device according to one of the preceding claims characterized in that helical blades are arranged on the flow passage so as to rotate it to ensure better movement of the product to be injected into the cavity to be filled. 6) Device according to either of the preceding claims, characterized in that an arrival of glue or any other additive is added. This arrival of glue or additive is distributed in the wool either before or after the nozzle. injection (16). In this case the dispensing of the additive or the glue is done through the orifices (5) formed in the jet deflector (4). The additive or glue can be supplied by pressure or by passage through a venturi.  7) Devices according to one of the preceding claims, characterized in that a pressure tap (117) makes it possible to control a pressure switch which determines the stopping of the supply of product to be injected as soon as the overpressure inside the system d injection exceeds a preset setpoint.  8) Device according to one of the preceding claims, characterized in that an additional air inlet (18) causes a rotational movement facilitating the ejection of the product and the filling of the cavity, and allowing instant unblocking of the nose ( 16) of the ejection nozzle.