CENTRIFUGAL LIQUID SPRAYING DEVICE WITH FRICTION-FREE DYNAMIC SEAL

Abstract

The present invention relates to a centrifugal spraying device for a liquid product, said device comprising a movable rotary electric motor (1) rotating about an axis (XX') and disposed in a concentric sleeve (2). The centrifugal spraying device according to the invention is configured so as to prevent liquid from entering the electric motor (1), without resorting to static sealing elements such as seals or sealed ball bearings, by taking advantage of the rapid rotation of the motor (1) to create an air overpressure in the vicinity of the motor's axis of rotation (XX'), thereby directing all of the liquid away from the motor's axis of rotation. Figure for the abbreviation: 1

Description

Title of the invention: CENTRIFUGAL LIQUID SPRAYING DEVICE WITH FRICTION-FREE DYNAMIC SEAL Technical field of the invention

[0001] The present invention belongs to the technical field of centrifugal liquid spraying devices. More particularly, the present invention relates to such devices in which sealing is achieved dynamically. Technical background

[0002] Currently, centrifugal liquid spraying devices known to those skilled in the art typically comprise a rotary electric motor rotating about an axis and disposed within a concentric sleeve, a disc support mounted on the motor shaft, and a thin rotating disc fixed to this disc support. The motor enables the disc to rotate at a very high speed. The sleeve is generally capped with a capsule whose upper face is very close to, but not in contact with, the lower face of the disc. A network of channels formed within the sleeve and the capsule to create a continuous and sealed system allows the liquid to be introduced into these spraying devices.Because the speed of the disk is very high, the liquid is broken down into a multitude of very small droplets as soon as it comes into contact with the disk, and these droplets are then projected at high speed in all directions, in the plane of the disk.

[0003] In such centrifugal liquid spraying devices, while almost all of the liquid is sprayed, residual volumes of liquid sometimes do not come into contact with the underside of the rotating disc and flow towards the motor shaft, thus constituting a risk of failure of mechanical, electrical or electronic components within the motor by corrosion or flooding.

[0004] To mitigate such a risk of failure, a conventional solution is to place a seal or a sealed ball bearing between the shaft of the electric motor (rotating part) and the bore of the sleeve (stationary part) in order to contain any residual fluid upstream of the sensitive parts of the electric motor. However, since the rotational speed of the electric motor is very high, these components wear out rapidly, which implies frequent maintenance operations, or even a risk of premature failure. Description of the invention

[0005] In order to overcome the aforementioned drawbacks, the applicant has developed a device centrifugal spraying of a liquid product to prevent liquid from entering the electric motor, without using static sealing devices such as seals or sealed ball bearings, by taking advantage of the rapid rotation of the motor to create an overpressure of air in the vicinity of the axis of rotation of the motor, which has the effect of directing all of the liquid so that it moves away from the axis of rotation of the motor.

[0006] More specifically, the applicant has developed a centrifugal spraying device for a liquid product comprising:

[0007] - a mobile rotary electric motor rotating around an axis of rotation XX', said rotary electric motor comprising a rear part of diameter D and axis of symmetry and a front part of diameter d disposed in the extension of said rear part and with the same axis of symmetry, with d being less than D,

[0008] - a static chamber) in the form of a sheath arranged concentrically to the said a rotating electric motor with respect to said axis of rotation XX' and partially surrounding the rear part of the rotating electric motor, said static chamber having a rear face and a front face, said static chamber comprising a first means for conveying the liquid to be sprayed formed longitudinally to allow said liquid to flow from the rear face of the static chamber to the front face of the static chamber,

[0009] - a support designed to be mounted concentrically on the front part of said electric motor and on which is fixed

[0010] - an object with axial rotational symmetry such as a flat disk, preferably of thin (specifically on the order of 0.1 to 1 mm), this disc being suitable for being driven in rotation at high speed by said rotary electric motor,

[0011] - a capsule fitted concentrically onto said front face of the chamber static, so that the upper face of said capsule is disposed just below said flat disc to avoid any contact with said flat disc, being separated from it by a distance e (preferably between 0.05 mm and 0.5 mm), said capsule having an inner lateral face surrounding said support, said capsule comprising a second means for conveying the liquid to be sprayed formed longitudinally to allow said liquid to flow from said front face of the static chamber to the face of said flat disc located opposite the upper face of said capsule, said first and second means of conveying,said capsule and said static chamber being arranged in said centrifugal spraying device in such a way that said first and second conveying means are in fluidic communication and form a continuous network, allowing the liquid to be sprayed from the rear face of the static chamber to the face of said flat disc located opposite the upper face of said capsule, ,

[0012] the spraying device according to the invention being characterized in that it further comprises blind orifices formed radially in said support and extending radially towards the axis XX', and

[0013] in that said inner face of said capsule has the shape of a diverging nozzle whose section perpendicular to the axis XX' has a diameter increasing up to the level of the upper face of the capsule.

[0014] Advantageously, the electric motor can be mounted in the sheath by means of several screws.

[0015] As means of conveyance (first and second means of conveyance), pipelines, and in particular cylindrical pipelines, will be used advantageously.

[0016] As regards the blind orifices formed radially in the support (in particular by machining or molding, or any other forming method suitable for this technology), they allow the creation of air pockets. Preferably, they can be in the form of turbine blades or cylinders.

[0017] The combination of the presence of radially formed blind orifices in the support and the diverging nozzle-shaped inner face of the capsule results in the air contained in the blind orifices in the support being subjected to a centrifugal force when the engine is rotating rapidly. This creates an air pressure gradient, with an overpressure outside the blind orifices (or pockets) and an underpressure near the axis of rotation. The combination of the nozzle geometry and this air pressure gradient induces an airflow towards the front, where the bore diameter is larger.The channels promoting air circulation around the motor allow this airflow to establish itself stably, so that it opposes any potential liquid flows towards the motor axis while redirecting them outwards, thus ensuring that all of the liquid comes into contact with the underside of the rotating disc and consequently its atomization and ejection.

[0018] Advantageously, the continuous network enabling the delivery of the liquid to be sprayed can be made sealed using O-rings arranged respectively between the capsule and the static chamber, as well as between the rotary electric motor and the support.

[0019] Advantageously, the device according to the invention may further include a fitting for introducing the liquid to be sprayed into the device according to the invention, this fitting being disposed on the rear face of the static chamber so as to be in fluidic communication with the continuous network. The liquid to be sprayed, which is thus introduced into the device via the fitting, can be set in motion by means of a pump (not shown), and then conveyed through the network of pipes to come into contact with the underside of the disc.

[0020] Advantageously, the device according to the invention may further include a high-flow fan disposed beneath the device according to the invention. By creating a powerful airflow, it deflects the trajectory of the droplets in a direction parallel to the axis of rotation of the disc.

[0021] Advantageously, the device according to the invention may further include a tachometer adapted to control the rotation speed of the motor, so as to prevent the liquid to be sprayed from entering the device according to the invention when the disc rotates at nominal speed.

[0022] Other advantages and features of the present invention will result from the following description, given by way of non-limiting example and made with reference to the following figures and examples. Brief description of the figures

[0023] The following examples illustrate the invention, in conjunction with the figures discussed above, without however limiting its scope:

[0024] [Fig-1]: [Fig.1] is a schematic perspective representation showing the cross-section of an example of a centrifugal spraying device according to the invention (the internal parts of the device being illustrated on the section and the external parts in perspective);

[0025] [Fig.2]: [Fig.2] is also a schematic perspective representation showing the cross-section of the centrifugal spraying device shown in [Fig.1], but without the rotating flat disc;

[0026] [Fig.3]: [Fig.3] is a schematic cross-sectional representation of the centrifugal spraying device shown in [Fig.1] (with rotating flat disc);

[0027] [Fig.4]: [Fig.4] is a detailed view of [Fig.3] showing more specifically the fitting of capsule 6 onto the sheath 2 and the inner face of the nozzle-shaped capsule; and

[0028] [Fig. 5]: [Fig. 5] is a schematic representation in full perspective of the centrifugal spraying device. Detailed description of the invention

[0029] Figures 1 to 4 schematically illustrate an example of a centrifugal spraying device according to the invention 1 comprising:

[0030] - a rotary electric motor 1 mobile in rotation around an axis of rotation XX' and comprising a rear part 11 of diameter D and axis of symmetry XX' and a front part 12 of diameter d arranged in the extension of the rear part 11 and with the same axis of symmetry XX', with d being less than D (D and d visible in figures 3 and 4), the rotary electric motor 1 being mounted by means of screws 3 in

[0031] - a sheath 2 having a rear face 21 and a front face 22, the sheath 2 being arranged concentrically to the rotary electric motor 1 with respect to the axis of rotation XX', so as to partially surround the rear part 11 of the motor 1, the sheath 2 having a first channel 7 formed longitudinally to allow the liquid to flow from its rear face 21 to its front face 22,

[0032] - a support 4 (or disk support) designed to be mounted concentrically on the front part 12 of the electric motor 1 and on which is fixed

[0033] - a thin flat disk 5 (visible in Figures 1 and 3 only), suitable to be driven into high-speed rotation by the rotary electric motor 1,

[0034] - a capsule 6 fitted concentrically onto said front face 22 of the sheath 2, so that its upper face 61 (visible in [Fig.2] only) is positioned just below the flat disk 5 to avoid any contact with the flat disk 5, separated from it by a distance e, 1

[0035] - the capsule 6 having an inner lateral face 62 (visible in figures 3 and 4) surrounding the support 4, the capsule 6 includes a second channel 8 formed longitudinally to allow the liquid to flow from the front face 22 of the sleeve 2 to the face of the flat disc 5 located opposite the upper face of said capsule 6, the channels 7, 8, the capsule 6 and the sleeve 2 being arranged so that the channels 7, 8 are in fluidic communication and form a continuous network 9 allowing the liquid to be sprayed to be conveyed from the rear face 21 of the sleeve 2 to the face of the flat disc 5 located opposite the upper face of the capsule 6, this inner face 62 having the shape of a diverging nozzle whose cross-section perpendicular to the axis XX' has a diameter increasing up to the level of the upper face 61 of the capsule 6, and finally

[0036] - blind orifices 41 (visible in figures 3 and 4) in the form of channels, in particular cylindrical ones formed radially in the support 4 and extending radially towards the axis XX'.

[0037] Figures 1 to 4 further show that the device 1 according to the invention also includes O-rings (static seals) 10 and 111 arranged respectively between the capsule 6 and the sleeve 2 (seal 10), and between the motor 1 and the support 4 (seal 111), to seal the continuous network 9 allowing the delivery of the liquid to be sprayed in the device 1 according to the invention.

[0038] Fig. 5 shows in particular that the device according to the invention can further include a fitting 112 for introducing the liquid to be sprayed, this fitting 112 in fluidic communication with the continuous network 9 being disposed on the rear face 22 of the sleeve 2. EXAMPLES

[0039] EXAMPLE 1 (comparative)

[0040] Between 2020 and 2022, the Applicant sold or replaced (corrective maintenance) an average of fifty motors per year on various machines. These machines were equipped with one or two prior art spray heads: specifically, these prior art spray heads comprise a rotary electric motor rotating around an axis and housed in a concentric sleeve, a disc support mounted on the motor shaft, and a thin rotating disc fixed to this disc support. The sleeve is capped with a capsule whose upper face is very close to the lower face of the disc without, however, being in contact with it. A network of channels formed within the sleeve and the capsule to create a continuous and sealed system allows the liquid to be introduced into these spray devices.Unlike the spraying device according to the invention, there are no radially formed blind orifices in the support, and the inner face of the capsule does not have the shape of a diverging nozzle, but rather a sealing gasket or a sealed ball bearing between the shaft of the electric motor and the bore of the sleeve. With such motors, a high rate of problems has been observed, specifically corrosion caused by liquid penetration along the rotor, which is the main source of motor deterioration and therefore necessitates their replacement.

[0041] EXAMPLE 2 (according to the invention): centrifugal spraying of water

[0042] The centrifugal spraying device according to the present invention and as shown in Figures 1 to 5 was tested on a standard disinfectant dispenser, the usual device (with static sealing) having been replaced by a prototype of the invention, in a relatively unconstrained environment: a warehouse with a ceiling height of 8 m, using water as the liquid to be sprayed, so that the environment was neither saturated (significant dispersion effect throughout the entire volume of the warehouse) nor exposed to chemicals (tests with water). The tests consisted of verifying that the liquid did not penetrate upstream of the motor shaft. The tests were carried out over a period of approximately 6 months, corresponding to about sixty hours of machine operation. At the end of this testing phase, the following observations were made:

[0043] - no engine degradation, which confirms the effectiveness of the process sealing,

[0044] - the motor's consumption at rated speed did not increase by compared to that which would be achieved using a static sealing system, meaning no performance degradation attributable to any degradation,

[0045] - finally, a visual examination of the engine shows the absence of any traces of liquid or corrosion upstream of the motor shaft.

[0046] EXAMPLE 3 (according to the invention): Centrifugal spraying of hydrogen peroxide

[0047] The same device as in Example 1 was used to operate under normal conditions commonly encountered in the sectors of activity in which the company operates. This device was installed in a 31 m³ room with a 2.5 m ceiling height. The disinfection operations were carried out according to the protocols usually recommended by the company: vaporization of hydrogen peroxide and validation of the decontamination performance using biological indicators. Fifteen successive tests were conducted, confirming that the decontamination results met expectations and that the machine's motor had not suffered any damage at the end of all the test operations. References

[0048] 1: rotary electric motor

[0049] 11: rear part of the rotary electric motor,

[0050] 12: front part of the rotary electric motor,

[0051] 2: a static chamber,

[0052] 21: rear face

[0053] 22: front face

[0054] 3: screw for fixing the motor 1 in the static chamber (description only),

[0055] 4: a flat disk support,

[0056] 5: disk-plane

[0057] 6: capsule

[0058] 61: upper face

[0059] 62: inner lateral face in the shape of a nozzle

[0060] 7: first means of conveying the liquid to be sprayed,

[0061] 8: second means of conveying the liquid to be sprayed

[0062] 9: continuous network comprising the first and second means of routing 7, 8,

[0063] 10: O-ring between capsule 6 and static chamber 2

[0064] 111: O-ring between the rotary electric motor 1 and the support 4.

[0065] 122: connection.

Claims

Claims

1. Device for centrifugal spraying of a liquid product comprising: - a rotary electric motor (1) rotatable about an axis of rotation (XX'), said rotary electric motor (1) comprising a rear part (11) of diameter D and axis of symmetry (XX') and a front part (12) of diameter d arranged in the extension of said rear part (11) and of the same axis of symmetry (XX'), with d being less than D, - a static chamber (2) in the form of a sheath arranged concentrically with said rotary electric motor (1) relative to said axis of rotation (XX') and partially surrounding the rear part (11) of said rotary electric motor (1), said static chamber (2) having a rear face (21) and a front face (22),said static chamber (2) comprising a first conveying means (7) for the liquid to be sprayed formed longitudinally to allow said liquid to circulate from the rear face (21) of the static chamber (2) to the front face (22) of the static chamber (2), - a support (4) designed to be mounted concentrically on the front part (12) of said electric motor (1) and on which is fixed - an object with axial revolution symmetry such as a flat disc (5), capable of being driven in rotation at high speed by said rotary electric motor (1), - a capsule (6) fitted concentrically on said front face (22) of said static chamber (2), so that the upper face (61) of said capsule (6) is arranged just below said flat disc (5) to avoid any contact with said flat disc (5), being separated therefrom by a distance e, said capsule (6) having an inner lateral face (62) surrounding said support (4),said capsule (6) comprising a second conveying means (8) for the liquid to be sprayed formed longitudinally to allow said liquid to circulate from said front face (22) of the static chamber (2) to the face of said flat disc (5) located opposite the upper face of said capsule (6), said first and second conveying means (7, 8), said capsule (6) and said static chamber (2) being arranged in said centrifugal spraying device so that said first and second conveying means (7, 8) are in fluid communication and form a continuous network (9) allowing the conveying of the liquid to be sprayed from the rear face (21) of the static chamber (2), up to the face of said flat disc (5) located opposite the upper face (61) of said capsule (6), said spraying device being characterized in that it further comprises blind orifices (41) formed radially in said support (4) and extending radially towards the axis (XX'), and in that said inner face (62) of said capsule (6) has the shape of a divergent nozzle whose section perpendicular to the axis (XX') has a diameter increasing up to the level of the upper face of the capsule (6).

2. Device according to claim 1, according to which said continuous network (9) allowing the conveyance of the liquid to be sprayed is made watertight using O-rings (10) and (111) arranged respectively between said capsule (6) and said static chamber (2) and between said rotary electric motor (1) and said support (4).

3. Device according to any one of claims 1 and 2, further comprising a connector (112) for introducing the liquid to be sprayed into said device, said connector (112) being arranged on the rear face (22) of said static chamber (2) and in fluid communication with said continuous network (9).

4. Device according to any one of claims 1 to 3, according to which the distance e between the upper face (61) of said capsule (6) and said flat disc (5) is between 0.05 mm and 0.5 mm.

5. Device according to any one of claims 1 to 4, according to which said blind orifices (41) formed radially in said support (4) are in the form of turbine blades or cylinders.

6. A device according to any one of claims 1 to 5, further comprising a tachometer adapted to monitor the rotational speed of the engine.

Images