STANDALONE DEVICE FOR PRODUCTION OF FOAM WITH BUILT-IN BREATHING DEVICE

Description

[0001] The present invention relates to a self-contained foam generating device with an integrated breathing apparatus.

[0002] It will be useful in particular in decontamination or depollution work, in which foams must be applied to large surfaces which may be steeply inclined or vertical, or in volumes, belonging for example to buildings or other immobile structures, which may be difficult to access, and must remain on these surfaces for a time long enough to act on the polluting products, without running or degrading in any other way.

[0003] The foams used may be viscosified, i.e. enriched with a gelling agent which increases the physical stability of the foams and makes them less likely to flow on even very inclined or vertical surfaces. Examples are given in FR 2 841 802 A1. The invention is not, however, limited to these particular foams.

[0004] A problem with these treatments, often carried out in hostile environments, is that the operator may have to face toxic atmospheres due to gases or fumes, and must then be provided with respiratory assistance.

[0005] An example of a foam generating device is described in W0 2013 / 067401 A2; this device is partially portable, designed for firefighting, but without breathing assistance.

[0006] CN110251865 A describes a foam spraying apparatus in which a compressed air cylinder that supplies the gaseous fraction of the foam also supplies a breathing mask through another conduit. An alarm device warns the user of impending air exhaustion.

[0007] An object of the invention is to integrate, under better conditions than in the last document above, respiratory assistance for the operator into the rest of the apparatus and in particular into the on-site manufacture of the foam.

[0008] Other objects of the invention are: to be able to transport the device without difficulty to places that are difficult to access and without any source of supply, for example water or electricity; and to offer certain safety advantages to the operator.

[0009] According to a general definition, the invention relates to a foam generation device, comprising a reservoir of a foaming liquid, a container of compressed air, a first conduit exiting the reservoir and passing through a pneumatic pump while being connected to suction and discharge ports of said pneumatic pump, a second conduit exiting the container, which ends at the pneumatic pump, the first conduit and the second conduit leading to a mixer of the foaming liquid and the compressed air, in which the foam is formed; the second conduit comprising a bifurcation, provided with an atmospheric pressure regulator, which leads to a breathing apparatus intended for an operator of the device; characterized in that the second conduit is provided with a shutter downstream of the bifurcation;and the shutter is associated with a compressed air pressure tap at the outlet of the container, which automatically closes the shutter when said pressure falls below a threshold, thus automatically cutting off the supply of compressed air to the pneumatic pump and to the mixer in order to reserve the air for the breathing of the operator wearing the breathing apparatus.;

[0010] The residual air is thus allocated entirely to the user's breathing, which increases their safety.

[0011] According to some optional improvements: the bifurcation comprises a branch ending at a valve of one half of a quick coupling, intended to connect another breathing apparatus; the shutter is a valve pushed back by the compressed air in the pressure tap and pushed back in the opposite direction by a spring; the apparatus comprises a pressure reading manometer connected to the second conduit.

[0012] The invention will now be described in its various aspects, characteristics and advantages, by means of the following figures, which illustrate a particular embodiment, given for purely illustrative purposes: there Figure 1 is a diagram of an embodiment of the invention; the Figure 2 represents the mixer; the Figure 3 represents the end of the projection lance; the Figure 4 illustrates a concrete arrangement of the realization; the Figure 5 represents an additional detail of the realization; and the Figure 6 represents another additional detail of the realization.

[0013] Referring to the figure 1 , the apparatus comprises a reservoir 1 of foaming solution in the liquid state, a container such as a bottle 2 of compressed air, a pressure gauge 3, a main regulator 4, a pneumatic pump 5, a mixer 6, a foam ejection end 7, a frame 8, a breathing mask 9 and a connector, called a Y, 10. A first conduit 11 connects an outlet orifice of the reservoir 1 to a suction orifice 12 of the pneumatic pump 5; it emerges from the pneumatic pump 5 through its discharge orifice 13, passes through the mixer 6 and ends at the end 7. A second conduit 14 connects an outlet orifice of the bottle 2 to the main regulator 4, then joins the first conduit 11 at a junction 15 made between the discharge orifice of the pneumatic pump 5 and the mixer 6.A branch 16 of the second conduit 14 leads to an orifice 17 for setting the rotor of the pneumatic pump 5 in motion (possibly via a second pressure reducer 43 to independently adjust the pressure at this point); another branch 18 leads to the breathing mask 9. Since the main pressure reducer 4 still delivers compressed air at a pressure significantly higher than ambient pressure, the compressed air is supplied to the breathing mask 9 after passing through a third pressure reducer 19 at the outlet of the branch 18, which expands the compressed air to 1 bar. The third pressure reducer 19 can be integrated into the breathing mask 9. The branches 16 and 18 leave the second conduit 14 just downstream of the main pressure reducer 4 and therefore transport slightly compressed air at constant pressure (7 bar for example).The pressure gauge 3 is connected by a pressure tapping conduit 20 to the second conduit 14, upstream of the main regulator 4, and it therefore makes it possible to measure the gas pressure at the outlet of the bottle 2 and to evaluate the filling of the latter.

[0014] The chassis 8 carries the tank 1, the bottle 2, the main regulator 4, the pneumatic pump 5, at least a first portion of the first conduit 11 and the second conduit 14. As shown in the figure 4 , the frame 8 can be vertical and belong to a backpack carried by the operator of the device; the frame 8 can also be a rolling trolley, for example. The breathing mask 9 is not fixed to the frame 8, and the bifurcation 18, at the end of which it is located, is flexible, which allows the operator to put on the breathing mask 9, or on the contrary to move it aside. The foam ejection end 7 is also not fixed to the frame 8, but it is located at the end of a flexible lance 21, which the operator holds and which extends to the junction 15.

[0015] The mixer 6 can be placed upstream of the lance 21. It is shown in figure 2 It comprises two flat grids 28 following one another in the bore 24 of a cylindrical wall and occupying its entire section, two sealing joints 29 to which the grids 28 are respectively fixed and which serve as support for the wall of the bore 24, and two spherical and rigid balls 30 free to move between the grids 28. The sealing joints 29 serve to hold the grids 28 in place and to form between them a cage 31, still delimited by the wall of the bore 24, and in which the balls 30 are retained. They also force all the fluids circulating in the bore 24 to pass through the interior of the cage 31. The mixer 6 thus defined can occupy the entire volume of the bore 24 or almost, that is to say that the upstream grid 28 is close to the inlet of the bore 24, and the downstream grid 28 rests on the rear face of an end piece 26 which constitutes the end 7.

[0016] Other embodiments of the mixer 6 would also be suitable for a good implementation of the invention.

[0017] There figure 3 shows that the end 7 is attached to one end of a barrel 33 of a gun 32 held by the operator; the other end of the barrel 33 is joined to the lance 21. The operator opens the lance 21 by pressing a trigger 35 of the gun 32. The supply of the breathing apparatus 9 remains whatever the state of the trigger 35.

[0018] There figure 4 illustrates a possible arrangement of the equipment on chassis 8, where a spare tank 1' is still shown, used when the first (tank 1) has been emptied.

[0019] There figure 5 illustrates that the bifurcation 18 is provided with a branch 38, which completes the Y-connector 10, at the end of which is placed a valve 39 of one of the halves of a so-called quick connector of known type. The branch 38 is used to add a second breathing mask for another operator, identical to the breathing mask 9, or to connect to an air hose for assistance, if necessary: ​​it is sufficient to couple a supply conduit of this mask, equipped with the other half of the quick connector, to the valve 39.

[0020] There figure 6illustrates an additional safety improvement, consisting of a switching device 40 which automatically cuts off the supply of compressed air to the pneumatic pump 5 and to the lance 21 when the bottle 2 begins to empty and the air pressure at its outlet falls below a threshold, in order to reserve the air for breathing by the operator wearing the breathing mask 9. A valve 41 controlling the supply to the pneumatic pump 5 and the lance 21 is then switched to cut off the supplies. The operation can be automatic if it is controlled by a pressure tap 42 of the second conduit 14 upstream of the main regulator 4, which presses on the valve 41 against the action of an opposing spring. Other embodiments of automatic switching or cutting devices are possible; it is also possible simply to rely on the indications of the pressure gauge 3.

[0021] Here is how the operation of the device and its advantages can be described. Since the device is free from any servitude, that is to say, any supply from the outside, the operator can put it on or transport it without constraint to remote or inaccessible places. He grasps the lance 21 by the gun 32 and presses the trigger 35 when he is in front of the surface to be covered with foam. The opening of the lance 21 allows the compressed air to flow through the second conduit 14. Part of the flow passes through the pneumatic pump 5, starts it up and is used to suck an invariable flow, proportional to the air flow passing through the pump 5, of the foaming solution from the tank 1. The pumped foaming solution and the main flow of compressed air, which is directed towards the lance 21, converge at the junction 15, upstream of the mixer 6.Here too, the flow rate of the foaming solution and that of the compressed air which mixes with it are proportional and therefore have an invariable ratio, determined by the physical characteristics of the fluids and the device. The foam is formed by the mixing of the air and the foaming solution, passing through the mixer 6. The grids 28, and especially the balls 30, are very effective in obtaining a foam with high expansion, that is to say with a low liquid fraction.

[0022] Some additional indications, of a concrete nature, are given below to describe more fully a particular example of this realization of the device and its performances. Bottle 2: capacity of 3l, starting pressure of 300 bar; Tanks 1 or 1': capacity of 8l each; Main regulator 4: reduces the pressure to 7 bar; Second regulator 43: reduces the pressure to 4 bar; Foaming solution: water, with Glucopon 215UP [BASF] at 10g / l, and Xanthan Gum (G1253) [Sigma Aldrich] at 3g / l;

[0023] Layer projected onto vertical surface: 10m 2< , 1cm thick, in 120s; sliding speed less than 1cm / min. In the case where the foam is used to fill a volume, the foam holding time is at least 120min;

[0024] Expansion of the foam obtained: approximately 16.7 (approximately 100 liters of foam produced for 6 liters of foaming solution consumed).

[0025] The balls 30 could be replaced by another solid body freely movable in the cage 31, and their number could also be different, only one solid body being possible.

Claims

1. Foam-generating device, comprising: - a reservoir (1) of foaming liquid, - a container (2) of compressed air, - a first pipe (11) leaving the reservoir (1) and passing through a pneumatic pump (5), being connected to suction (12) and delivery ports (13) of said pneumatic pump (5), - a second pipe (14) leaving the container (2) and ending in the pneumatic pump, - the first pipe and the second pipe leading to a mixer (6) of the foaming liquid and compressed air, wherein the foam is formed; - the second pipe (14) comprising a bifurcation (18), fitted with an atmospheric pressure expansion valve (19), which leads to a breathing apparatus (9) intended for an operator of the device; characterized in that - the second pipe (14) is fitted with an obturator (41) downstream of the bifurcation (18), and in that the obturator is associated with a compressed air pressure tap at the outlet of the container, which automatically closes the obturator (41) when said pressure drops below a threshold, thereby automatically cutting off the supply of compressed air to the pneumatic pump and the mixer (6) in order to reserve the air for the breathing of the operator wearing the breathing apparatus.

2. Foam-generating device according to Claim 1, characterized in that the bifurcation (18) comprises a branch (38) finishing at a valve (39) of a quick coupling half, intended to connect to another breathing apparatus.

3. Foam-generating device according to Claim 1 or 2, characterized in that the obturator is a valve pushed back by the compressed air in the pressure tap and pushed back in the opposite direction by a spring.

4. Foam-generating device according to one of Claims 1 to 3, characterized in that it comprises a pressure reading gauge connected to the second pipe.