FR2845017A1 - DEVICE FOR CLEANING BY SPRAYING A POWDER / GAS MIXTURE UNDER REGULATED PRESSURE - Google Patents

Abstract

The present invention relates to a device for cleaning the surface of a support, by spraying onto this surface a flow comprising a mixture of abrasive particles and compressed air or another gaseous fluid under pressure, this mixture being produced in a circuit or a tank (1) of mixture supplied with compressed air and receiving or containing a powder of abrasive particles, this mixture being projected through a projection orifice (40) of a projection handle (4) operated by a operator, characterized in that the pressure of the projected air is regulated by a regulator (20) controlled by an electronic circuit (6), receiving on the one hand information supplied by at least one pressure sensor (5) and representing the air pressure downstream of this regulator (20), and on the other hand electrical information supplied by an adjustment device actuated by the operator and representing a setpoint value to be obtained for the air pressure in downstream of the regulate ur (20).

Description

Device for cleaning by spraying a powdery gas mixture under

  regulated pressure The present invention relates to a device for cleaning the surface 5 by spraying gaseous fluid charged with particles, humidified or not, presenting possibilities of adjustments to the handle with a response time.

  decreased and a locked settings allowed.

  The cleaning by spraying of surfaces which are in particular non-planar or which have a non-smooth surface state constitutes a field of technical development in terms of the materials available. These materials no longer apply

  often cleaning or stripping exterior surfaces, for example walls or slabs, made of materials such as stone, concrete, brick, plaster.

  The purpose of this cleaning is generally to remove one or more layers of dirt, such as pollution or oxidation, or coating such as paint or graffiti or chewing gum. A technique, known as

  name of gumming and developed for about twenty years, consists in projecting on the surface to clean fine abrasive particles in air under pressure. Depending on the types of surfaces to be cleaned, this exfoliation can be carried out in the form of a hydro-exfoliation, by adding water in variable quantity to the mixture of air and particles.

  This technique can be applied in many fields, which range from cleaning public buildings or monuments to cleaning antiques or archaeological pieces. Depending on the type of surface to be cleaned, the nature of the powders used may vary as well as the pressure of the air used to spray the particles. For the same type of particles, a higher pressure will allow a more effective cleaning or pickling for resistance stains, and also a faster process for a support having a large surface. On the other hand, too much pressure can easily damage the surface to be cleaned in itself and destroy its reliefs. In a good number of cases, it is therefore important to be able to obtain and maintain an air pressure chosen according to a compromise between the effectiveness of cleaning.

  and safeguarding the support surface to be cleaned.

  Patent FR 2 709 257 discloses a hydrogumming device using an air compressor to pressurize a reservoir containing an abrasive powder. In its lower part, this reservoir expels air charged with particles by a pipe leading to a projection handle provided with a trigger which can interrupt the projection. This handle is also connected to a water inlet at a pressure of around 60 bars. This water is used to moisten the sprayed mixture without increasing the pressure, or to rinse the surface to be cleaned by spraying water only. In this device, the regulation of the air pressure, which conditions the effectiveness and the aggressiveness of the projection, is done by a manual regulator located at the entry of the mixing tank. The handle or the spray lance is at the end of a pipe of a certain length and can be moved to the support to be cleaned, even at a great distance from the tank. However, everything

  Changing the air pressure setting requires the presence of a different operator from the projection operator, or a displacement of the latter.

  This represents significant drawbacks in terms of personnel or working time, in particular when the support to be cleaned comprises 20 different parts requiring or allowing different adjustments.

  To improve this aspect of the implementation of such a method, patent EP 0 832 718 describes a device comprising a pressure adjustment, the control of which is offset at the level of the projection handle. This adjustment is made by two regulators, one at the inlet of the mixing tank, and the other on the handle. This handle regulator receives air regulated by the first, therefore at the tank pressure, and uses it to pneumatically control the adjustment of the tank inlet regulator, according to the

pressure it measures.

  However, this device has the disadvantage of a long response time during a change of setting, which can be up to 20 seconds, which means that work must be suspended for this duration during each of these changes. In addition, the slightest leak in the air lines between the tank regulator and the handle can cause variation in the

  pressure in this tank, without the operator noticing.

  Furthermore, compliance with the maximum or minimum pressure thresholds to be used rests solely with the operator, and this permanently during the duration of the cleaning site. Such a device provides the building owner, or the site sponsor, with few guarantees other than the thresholds defined during

  initial tests will be observed on the entire surface to be cleaned.

  The object of the invention is to overcome one or more of these drawbacks. The present invention therefore aims to overcome the drawbacks of the prior art by proposing This object is achieved by a device for cleaning the surface of a support, by spraying onto this surface a flux comprising a mixture of abrasive particles and compressed air or other gaseous fluid under pressure, this mixture being produced in a circuit or a mixing tank supplied with compressed air and receiving or containing a powder of abrasive particles, this mixture being sprayed through a projection orifice of a projection handle operated by an operator, characterized in that the pressure of the projected air is regulated by a regulator controlled by an electronic circuit, receiving on the one hand information supplied by at least one sensor pressure and representing the air pressure downstream of this regulator, and on the other hand electrical information supplied by a regulating device 25 actuated by the operator and representing a setpoint at

  obtain for air pressure downstream of the regulator.

  According to another particular feature, the device comprises storage means capable of storing electronic information representing at least one air pressure value to be obtained and corresponding to a maximum threshold or information corresponding to a minimum threshold or both, the circuit electronic being able to regulate the air pressure so that it does not exceed the maximum threshold value or does not decrease below the

  minimum threshold value or both.

  According to another particular feature, the device includes means 5 for identifying a control operator authorized to fix or modify the value of at least one of these thresholds.

  According to another particular feature of the device, the mixing is carried out in a mixing tank containing the abrasive powder and receiving compressed air by a pressure adjustment valve, the regulation of the air pressure in this tank being carried out by a regulating device, called positioner, receiving air at the pressure prevailing in the tank or information representing this pressure, by a measurement circuit, and controlling the pressure adjustment valve, by a pneumatic pressure control circuit or by electrical control of an actuator, the positioner comprising an electronic circuit comprising means for

  calculation communicating with means for measuring the pressure of the measurement circuit and controlling adjustment means able to supply the control circuit with air at a determined pressure, these calculation means using the information from these measurement means to supply the circuit control 20 so as to regulate the pressure in the tank.

  According to another feature of the device, the positioner comprises

  input means and means for storing one or more threshold values, these storing means communicating with the calculation means to provide them with information representing the threshold values to be respected.

  According to another particular feature of the device, the positioner comprises means for entering and means for storing at least one authorization code, the entry of this authorization code being necessary for entering

  or store one or more threshold values.

  According to another particularity, the adjustment device comprises a potentiometer or a rheostat supplied with a voltage lower than 48V, this adjustment device being integral with the projection handle and operating by displacement of a cursor, either linear or rotary according to a stroke of less than a turn. According to another particular feature, the device comprises a vehicle or a supporting frame supporting the mixing tank, an air compressor supplying this mixing tank, the positioner and the circuits carrying out the regulation of the pressure in the mixing tank, the handle of projection 10 being connected to the rest of the device by a supply beam of a length

  determined to allow the operator a certain autonomy of movement during cleaning without displacement of the chassis or of the carrier vehicle, this bundle comprising at least one pipe supplying the handle with a mixture to be sprayed and one or more electric wires transmitting the value of setpoint from the handle to the positioner.

  According to another particular feature, the device comprises means for adding at least one liquid to the projected abrasive mixture, as well as

  means for adjusting the quantity of liquid added to this mixture.

  According to another particular feature of the device, the projection handle 20 comprises means for projecting at least one liquid, this projection of

  liquid that can be done in the absence of projection of the abrasive mixture.

  According to another particular feature of the device, the carrier vehicle or chassis further comprises a liquid pressurization pump supplying the

  projection handle by the power beam.

  The invention, with its characteristics and advantages, will emerge more

  clearly on reading the description made with reference to the accompanying drawings

  in which: - Figure 1 shows a functional diagram of the device

according to the invention.

  - Figure 2 shows a diagram of the air pressure regulation system used in the invention - Figure 3 shows an overview and outside of the

device according to the invention.

  - Figure 4 shows a rear view of a vehicle

  incorporating the device according to the invention.

  The device for cleaning the surface of a support, by spraying onto this surface a flow comprising a mixture of abrasive particles and compressed air or another gaseous fluid under pressure will be described in connection with the figures. 1 to 4. The mixture of abrasive particles and compressed air is produced in a circuit or a tank 1 of mixture supplied with compressed air by a regulated air supply system 2. The tank 1 receives or contains a powder of abrasive particles, the mixture of which with a fluid is sprayed through a projection orifice 40 of a projection handle 4 controlled by a trigger 41 operated by an operator. The pressure of the air used to spray the mixture is regulated by a regulator 20 controlled by an electronic circuit 6, which receives on the one hand information supplied by at least one pressure sensor 5 arranged for example on the pistol grip 4 and representing the air pressure downstream from this regulator 20, and on the other hand from the electrical information supplied by an adjustment device 42 mounted on the spray gun handle and actuated by the operator. This electrical information provided by the adjustment device 42 represents a value of

  setpoint to be obtained for the air pressure downstream from regulator 20.

  The electronic circuit 6 includes storage means 60, 61, 25 62 able to store electronic information representing at least one value of air pressure to be obtained and corresponding to a maximum threshold 61 or information corresponding to a minimum threshold 60 or both, the electronic circuit 6 being able by software to control the regulation of the air pressure so that it does not exceed the maximum threshold value 30 or does not decrease below the minimum threshold value or both,

  stored in the two memories 60, 61. The electronic circuit 6 also includes software comparing an authorization code entered on an alphanumeric keyboard 63 of a control panel of the device with a value stored in a memory 62 of the electronic circuit 6 for 5 constitute means of identifying a control operator authorized to fix or modify the value of at least one of these thresholds.

  The mixing is carried out in a mixing tank 1 containing the abrasive powder 10 and receiving compressed air 23 by a pressure control valve 200. The regulation of the air pressure in this tank 1 is carried out by a regulating device 20, called positioner, receiving air 24 at the pressure prevailing in the tank 1 or information 25 representing this pressure, by a circuit of measurement. This information controls the pressure adjustment valve 200, by a pneumatic pressure control circuit or by an electrical control of an actuator. The positioner 15 20 comprises an electronic circuit comprising calculation means

  communicating with the circuit pressure measurement means for controlling adjustment means 21, 22 able to supply the control circuit with air at a determined pressure. These calculation means use the information from the measuring means to supply a control signal to the valve making it possible to regulate the pressure in the tank.

  The positioner 20 comprises in association with the electronic circuit

  6 input means and storage means 61, 60 of one or more threshold values, these storage means communicating with the calculation means of the electronic circuit 6 to provide them with information 25 representing the threshold values to be observed.

  The pistol grip includes a potentiometer or rheostat 42

  powered by a voltage less than 48V, this adjustment device is integral with the projection handle and operates by moving a cursor, either linear or rotary according to a stroke of less than one turn, to be supplied by the wires.

  The entire device is mounted on a vehicle or a supporting frame supporting the mixing tank 1, an air compressor 23 supplying this mixing tank, the positioner 20 and the circuits 6, 21, 22 carrying out the pressure regulation in the mixing tank, the projection handle 5 is connected to the rest of the device by a supply beam 9 of a determined length to allow the operator some autonomy of movement during cleaning without moving the chassis or of the carrier vehicle. This bundle 9 comprises at least one pipe supplying the handle with a mixture to be sprayed and one or more electrical wires 421 10 transmitting the set value from the rheostat 42 of the

handle 4 to the positioner.

  The device also comprises means 3 for adding at least one liquid to the projected abrasive mixture, as well as means 31, 7 for

  adjustment of the quantity of liquid added to this mixture.

  The projection handle comprises means 5 for projecting at least one liquid, this projection of liquid being able to take place in the absence of

  projection of the abrasive mixture controlled by the trigger 41.

  The vehicle 8 or supporting frame may further comprise a pump

  for pressurizing the liquid supplying the spray handle by the supply beam 20.

  Thus the pressure measurement and the adjustment being carried out near the operator, the suspension of working time is extremely reduced and the risk of mistreatment as a result of an error in the measurement or in the

settings is also eliminated.

  It should be obvious to those skilled in the art that the present invention allows embodiments in many other specific forms without departing from the scope of the invention as claimed. Therefore, the present embodiments are for illustrative purposes, but may be

  modified in the field defined by the scope of the appended claims, and the invention should not be limited to the details given above.

Claims (11)

  1. Device for cleaning the surface of a support, by spraying onto this surface a flow comprising a mixture of abrasive particles and compressed air or another gaseous fluid under pressure, this mixture being produced in a circuit or a mixing tank (1) supplied with compressed air and receiving or containing a powder of abrasive particles (10), this mixture being sprayed through a projection orifice (40) of a projection handle (4) operated by an operator, characterized in that the pressure of the projected air is regulated by a regulator (20) controlled by an electronic circuit (6), 10 receiving on the one hand information supplied by at least one pressure sensor (5) and representing the air pressure downstream of this regulator (20), and on the other hand electrical information supplied by an adjustment device (42) actuated by the operator and representing a set value to be obtained   for the air pressure downstream from the regulator (20).   2. Device according to claim 1, characterized in that it comprises storage means (60, 61, 62) capable of storing electronic information representing at least one value of air pressure to be obtained and corresponding to a maximum threshold (61) or information corresponding to a minimum threshold (60) or both, the electronic circuit (6) being able to regulate the air pressure so that it does not exceed the maximum threshold value   or does not decrease below the minimum threshold value or both.   3. Device according to one of claims 1 to 2, characterized in that it   includes means for identifying a control operator authorized to fix   or modify the value of at least one of these thresholds (60, 61).   4. Device according to one of claims 1 to 3, characterized in that   mixing is carried out in a mixing tank (1) containing the abrasive powder (10) and receiving compressed air by a pressure adjustment valve (200), regulating the air pressure in this tank (1 ) being produced by a regulating device (20), called a positioner, receiving air at the pressure prevailing in the tank (1) or information (25) representing this pressure, by a measuring circuit, and controlling the valve pressure adjustment (200), by a pneumatic pressure control circuit or by an electrical control of an actuator, the positioner comprising an electronic circuit comprising calculation means communicating with means for measuring the pressure of the pressure circuit measuring and controlling adjustment means capable of supplying the control circuit with air at a determined pressure, these calculation means using the information from these measurement means to supply the control circuit with fa how to regulate the pressure in the tank (1).   5. Device according to claim 4, characterized in that the positioner (20) comprises input means and means for memorizing one or more threshold values (60, 61), these memorizing means communicating with the means to provide them with   information representing the threshold values to be observed.   6. Device according to one of claims 4 to 5, characterized in that   the positioner (20) comprises means for entering and means for memorizing at least one authorization code (62), the entry of this authorization code being necessary for entering or memorizing one or more threshold values (60, 61).   7. Device according to one of claims 1 to 6, characterized in that   the adjustment device comprises a potentiometer or a rheostat (42) supplied with a voltage lower than 48V, this adjustment device being integral with the projection handle (4) and operating by moving a cursor, either   linear, or rotary according to a stroke of less than one turn.   8. Device according to one of claims 4 to 7, characterized in that   the device comprises a vehicle or a supporting frame (8) supporting the mixing tank (1), an air compressor (23) supplying this mixing tank (1), the positioner (20) and the circuits carrying out the regulation of the pressure in the mixing tank (1), the projection handle being connected to the rest of the device by a supply beam (9) of a determined length to allow the operator some autonomy of movement during the cleaning without moving the chassis or the carrying vehicle, this bundle (9) comprising at least one pipe supplying the handle (4) with a mixture to be sprayed and one or more electric wires (421) transmitting the set value from the handle (4 ) to the positioner (20).   9. Device according to one of claims 1 to 8, characterized in that   the device comprises means for adding (3) at least one liquid to the projected abrasive mixture, as well as means (31, 7) for adjusting the quantity   of liquid added to this mixture.   10. Device according to one of claims 1 to 9, characterized in that   that the spray handle (4) comprises means for spraying at least one liquid, this spraying of liquid being able to take place in the absence of spraying of the abrasive mixture.   11. Device according to one of claims 4 to 10, characterized in that   that the carrier vehicle or chassis (8) further comprises a liquid pressurization pump supplying the projection handle (4) by the beam supply (9).