FR2527126A1 - STACKING PLANT OF ANY SHAPED PIECES BY MEANS OF AN ORIENTABLE LANCE - Google Patents

Abstract

BLASTING INSTALLATION OF PARTS OF ANY SHAPES, INCLUDING AN ORIENTABLE LANCE 1 SUITABLE TO PROJECT A SHOTGUN ON THE PART, MOUNTED ON A 3 MOBILE PLATFORM. PLATFORM 3 IS VERTICALLY MOVABLE ON A FIXED BASE, LANCE 1 IS SLIDING FITTED AXIALLY THROUGH WALL 4 OF PLATFORM 3, AND ROTATING AROUND ITS AXIS BY MEANS OF A ROTATING JOINT 25, AND IT HAS A PROJECTION NOZZLE 5 OF SHOTGUN ARTICULATED SO AS TO BE ABLE TO BE INCLINED UP TO PERPENDICULAR WITH THE AXIS OF LANCE 1, A IMPELLER 76 BEING INSTALLED IN FRONT OF GLASS 11. THIS ARRANGEMENT ALLOWS NOZZLE 5 TO ALL DEGREES OF FREEDOM TO EXPOSE THE TOTALITY FROM PART TO SHOTGUN, WHILE TURBINE 76 PROTECTS GLASS 11 AGAINST SHOTGUN KICKBACK.

Description

The present invention relates to an installation

  blasting of parts of any shape, for example descrusting foundry pieces or forge to be de-scaled, by means of a directional lance capable of projecting a jet of shot on the piece. To carry out this type of shot blasting, one carries out currently in three ways: or in a purely manual way, the operator inside a cabin being covered with a kind of protective suit against the rebounds of shot and the dust , and bearing the full weight of the end of the spear, or the operator is located at

  outside and works with arms tied in gloves

  There are also facilities with a pod supporting the operator and vertically movable the piece to be blasted being disposed in a closed cabin along one of the walls of which moves the pod. , spear

  through this wall in a sealed manner by means of a

  appropriate, arranged further to provide guidance

  the lance in various directions to perfect the grenaille-

the room.

  the manual shot blasting in the cabin has many drawbacks: first of all, it is painful for the operator, who must remain for the duration of shot peening in a protective suit and must support the weight of the lance. the safety of the operator, who breathes air polluted by dust, and must also

  nuisance caused by the noise of shot blasting.

  manual shot blasting with gloves attached to the wall greatly reduces the operator's field of action, not to mention the fatigue caused by maneuvering the machine.

throws (even suspended).

  mechanical shot peening by means of a mobile nacelle is obviously much less painful for the operator, who is no longer exposed to the dust-filled atmosphere of the shot blasting cabin, and is relatively isolated from the

  On the other hand, other disadvantages are observed.

  This shows that the bounces of

  against the window pane dais dais The wall of the cabin, to allow the control blasting by the operator, depo-

  smooth in the long run, which must then be replaced

  The movements that the lance can execute in different directions are not always sufficient to complete the blasting of certain pieces of complex shape. Finally, even if the operator does not

  to bear all the weight of the spear, the maneuver of this: -

  it still requires manual efforts relative-n + imzorz-

  who become peril at the end of a certain time.

  The object of the invention is therefore to propose

  blasting plant of the kind comprising a mobile blasting machine

  the, which is arranged of metiir? eliminate these inconveniences.

  According to the invention, the installation is cao terized by the fact that, in combination, the nacelle eeg

  vertically displaceable - a support, the lance c-

  wears a terminal spray nozzle of grenvaille

  articulated on a tubular body of the lance, in order to

  put a proper orientation of the shot blast, the body of the lance is slid axially through

  the vertical wall of the nacelle, and a protection turbine

  the glass pane against the bounces of shot closing the observation opening of the wall is subject to the latter The combination of the vertical displacement of the nacelle, the axial displacement of the lance through the

  the nacelle wall and the nozzle of the

  jection on the body of the lance, allows the operator to position the spray nozzle in three dimensions at all the desired locations to allow Lu complete shot blasting of the entire surface of the piece to be blasted,

  even if this piece has a particularly complex shape.

  The addition of a turbine to the installation, mounted in front of the observation window of the nacelle, effectively protects the window by preventing the grains of shot from bouncing up to it, these grains being indeed caught by the and returned to the interior of the cabin before they could reach the window. Under these conditions, almost all the shot grains are

  actually stopped, which prevents

  gression of the window which does not need any more to be replaced

after a certain time.

  According to a feature of the invention, the tubular body of the lance is rotatably mounted about its axis on a fixed rotation connection, located on the operator's side relative to the wall of the nacelle, via a bearing provided with seals, one of which closes the bottom of an annular chamber opening inside the rotating body and the fixed connection, and means are provided for injecting compressed gas during shot blasting into the annular chamber in order to constantly push back the grains of shot tending to penetrate

  in this chamber and to damage the seal.

  The compressed gas, preferably air, is injected into the annular chamber via a conduit, or into a ring for holding the bearings and the seals integral with the rotating body, or in their fixed connection. advantage of securing the injection pipe of the compressed gas with

  a fixed part, instead of a rotating part.

  The injection of a ring of compressed gas into the junction zone between the rotating body and the fixed connection of the lance thus very effectively protects the seal located on this side, and if necessary the bearing

ball.

  According to another feature of the invention, the nacelle is suspended from a flexible vertical curtain carried by the frame and whose ends can be wound and unwind simultaneously around horizontal axes, one of which is coupled to a motor. and the sides of the nacelle are guided by vertical guides

of the frame.

  The turbine provided by the invention comprises

  blades whose angular deviation and rotation speed-

  are determined in correlation with the average velocity of shot grains projected towards the window, so that these grains are, in almost all cases, caught and returned by the blades before they could reach the window This turbine is driven by an electric motor attached to the wall of the nacelle, the inner side

to the shot blasting cabin.

  In one embodiment of the installation, -

  the projection nozzle-comprises a flexible tubing of which

  one end is attached to the tubular body, and this tubular

  The lure can be folded in a vertical plane to a position substantially perpendicular to the axis of the body of the lance by a device operable from the nacelle by the operator. Other features and advantages of

  the invention will appear during the description that will

  follow, with reference to the accompanying drawings which represent by way of example, an embodiment

non-limiting.

  Figure 1 is a perspective view of the mobile nacelle of the shot blasting system according to the invention. FIG. 2 is a perspective view of the interior of the shot blasting cabin, showing the portion

  of the inner lance & this one and a piece to be blasted.

  Figure 3 is a side elevational view

  on an enlarged scale of the installation of Figures 1 and 2.

  FIG. 4 is a front elevational view of the nacelle of FIG. 3 and of its support frame on which it is mounted vertically. FIG. 5 is a longitudinal half-elevation view of the lance fitted to the installation. , showing

  in particular an embodiment of its flexible nozzle.

  FIG. 6 is an axial half-sectional view, half

  elevation, on an enlarged scale, of the connection device

  from the flexible nozzle to the rigid body of the lance.

  Figure 7 is an elevational view

  arrow K in FIG. 5 of the device allowing the operation

  to control the flexion of the flexible injection nozzle

in a vertical plane.

  Figure 8 is a cross-sectional view

following VIII-VIII of Figure 5.

  Figure 9 is a top view partially broken away of the glass protection turbine

  of the nacelle, and its drive motor.

  Figure 10 is an elevational view of the -

  turbine and motor of Figure 8.

  FIG. 11 is an axial sectional view

  of the rotary joint arranged in the part of the outer lance

  than the shot blasting cabin, and allowing the spear

to turn around its axis.

  The installation shown in the drawings is intended for the blasting of parts of any shape for the descaling desabler or for any other shot blasting treatment It comprises a lance 1 adjustable, able to project a shot of shot on a part 2 (Figure 2), and a nacelle 3 for supporting the lance 1, which passes through

  the wall 4 about halfway up.

  The blasting lance 1 therefore comprises an outer portion -à to the shot blasting cabin in which is the piece 2, and an interior portion to this cabin, having a nozzle 5 shot projection The vertical wall 4 of the pod 3 is soliqaiçe a horizontal platform 6 capable of receiving utn operator 7 which controls the orientation and positiomnement of the lance 1 and its nozzle 5 by appropriate means 6 s :, including a handwheel 9 integral with the lance 1, monitoring the operation being possible by a glazed opening it made in the upper part of the wall 40 The nacelle 3 advantageously comprises a seat

  12 (Figures 3 and 4), allowing the operator 7 to sit.

  The nacelle 3 is mounted vertically movable on a fixed support frame 13, comprising two vertical uprights 14 connected at their apex by a cross member 15, which supports a flexible curtain 16 which is suspended from the nacelle 3

  last, hanging from the curtain 16, can slide vertically

  between the uprights 14 acting as slides, this sliding being guided by means of rollers 17 rolling

  on the uprights 14 (Figures 1 and 3).

  The ends of the flexible curtain 16 can

  curl up for one and unfold for the other, simul-

  at a time, about horizontal axes 18, 19, the upper axis 18 being placed on the crosspiece 15 and the lower axis 19 being fixed to the base of the uprights 14 The return rollers -i 2527126 7: 21 and 22 are mounted respectively at the top and at the base of the uprights 14 Finally, the vertical displacement of the curtain 16 and therefore the nacelle 3 is controlled by a geared motor 23 placed on the fixed frame 13 in the vicinity of the axis 18 (Figure 3). Under these conditions, when the curtain 16 is driven vertically in one direction or the other by the motor 23, the nacelle 3 suspended to this curtain slides vertically between the rails-constituted by the uprights 14 on which the guide rollers 17 roll.

  l-a launches 1 is fired by a shot

  flexible yau 20 (FIG. 1) in a manner known per se For each position in height of the nacelle 3, the lance 1 has several degrees of freedom which make it possible to properly position the injection nozzle 5 with respect to the part

to blast.

  Thus the lance 1 is: axially displaceable along the axis of its rigid tubular body 24 passing through the vertical wall 4, rotating about its axis XX '(FIG. 5) by means of a rotary joint 25 (see FIGS. 3 and 11), orientable inside a cone thanks to its articulation on the wall 4 by a ball joint device

26 (Figure 5).

  Finally the nozzle 5 of projection of the shot

  is flexible and articulated on the end of the tubular body.

  rigid 24 The articulation of the nozzle 5 is arranged to allow it to pivot from the horizontal to a downward inclined position, perpendicular

to the X-X 'axis of the lance 1.

  It is understandable that the combination of these differences

  opportunities for orientation and positioning of

  the nozzle 5 makes it possible to reach the most remote parts

  from Part 2 to shot blast, and to execute a grenaille-

  complete range of it regardless of the complexity of

its configuration.

  The means provided in the embodiment illustrated in the drawings will now be described to enable

  at lance 1 to execute the above moves.

  Articulation of the blasting lance 1 on

  the wall 4 of the nacelle (Figure 5) -

  The rigid tubular body 24 of the lance 1 treads

  pours two ball bearings 27 maintained by struts

  its 28, rings 29 coaxial with the body 24 and provided with seals 31, the spacers 28 being themselves

  arranged inside a spherical cap 32 or ball.

  Compressed air is injected between the two bearings 27, by means not shown to prohibit the introduction of shot The cap 32 is housed in a housing 33 which surrounds the body 24 and is fixed to the wall 4, of the c 8 external to the shot-blasting cabin by bolts or screws. Finally, all around the tubular body 24, the wall 4 has an annular opening 35 sufficiently large for

  allow angular movement of the lance 1 to the

  cone whose apex is the center of the ball 32 and whose edges pass through the periphery of the annular opening 35 The latter is closed by a membrane

  flexible 36 fixed on the one hand to the wall 4 by the screws 34.

  and on the other hand embedded in an annular groove of the

ring 29.

  The amplitude-of the angular clearance allowed by the ball joint 26 is therefore connected to the angular opening between the center of the ball 32 and the periphery of the ball joint.

the opening 35.

  To mechanically position the lance 1 within the cone defined above, the nacelle is equipped with a jack 36 (Figure 3) preferably electric, whose body is articulated on the wall 4 under the lance 1; and whose rod 37 is articulated on the outer ring 29 to

  the shot-blasting cabin The control of this electric cylinder

  36 exempts the operator from providing the effort to manually direct the lance, which he can however do in

  case of necessity with the help of the steering wheel 9.

  Device for articulating the projection nozzle relative to the body 24 of the lance

(Figures 5 and 6.

  The projection nozzle 5 comprises a flexible tube 38, one end 38a of which is embedded in the end piece 39 of the body 24, and fixed to this end piece by members such as screws 30. The opposite end 38b is also embedded. in a rigid end

  41 to which it is fixed by a ring 42 clamping tra-

  poured by screws 43 The length of the flexible tubing 38 is determined to allow it to be folded at an angle

  right with the X-X 'axis of the rigid body 24 (position representing

Figure 5).

  To allow the bending of the nozzle 5 to this orientation and of course the reverse maneuver, the invention provides a manoeuvrable control device

of the nacelle 3 by the operator.

  In the embodiment described, these means of maneuvering the nozzle 5 comprise two cables 44, preferably made of steel, diametrically opposed from each other.

  and other of the tubing 38 and which extend from the end

  38 b of it to a control device 45 mounted on the body 24 inside the nacelle 3.

  ends of the cables 38 are clamped between the ter-

  minal 41 and the screws 43 which thus ensure their retention in place at the end of the flexible tubing 38 Between the tip 39 and the tip 41, the cables 44 are maintained

2527126

  by several collars 46 coaxial to the tubing 38,

  means of screws not shown Between the mouthpiece 39 and the disc

  positive control 45, the cables 44 extend in a reserved annular space between the tubular body 24 and a coaxial sleeve 47 secured to the body 24 by a series

of screws such as 48.

  The means for controlling the inclination of the flexible nozzle 5 on the axis XX ', constituting Cspar the device

  are described hereinafter with reference to FIGS. 5 and 7).

  These means comprise two links 49 arranged on each side of the tubular body 24, secured by spacers 51 and rotatably articulated on pins 52 supported by the body 24 The spacers 51 are secured with the ends 44 to the cables 44, 1-5 by winding said ends around the spacers 51, so that the pivoting of the links 49 about their axes 52 causes a pull on wl cable 44 and a push on the other cable, which cause a

bending of the flexible nozzle 5.

  It can be seen in FIG. 5 that the ends 44 wound around the spacers 51 are held in place by means of a pin 52 inserted in the loop formed by the folded end 44, and by a ring 53

  squeezing the loop on the pin 52.

  The tilting of the rods 49 about their axes 52 is controlled, in this example, by a crank 54 fixed to a threaded rod 55 passing through a connecting piece 56 between the lower ends of the rods 49, in which it bears by means of

  bearings 57 sliding in oblong holes 58 of the bi-

your 49.

  The threaded rod 55 is supported at its ends.

  mitiated by the walls of a casing 59 which contains the links 49 and the walls of which are fixed the pins 52 The casing 59 is traversed by the tubular body 24, between the rods 49, and is supported on this body 24

by a piece 61.

  The operation of the flexible nozzle 5 by means of the control device which has just been described is easily understood: the nozzle 5 being in horizontal position in the extension of the tubular body 24, the rods 49 are in their extreme positions opposite to those shown in Figure 5, that is to say that their lower ends are at the end of the rod 55 opposite the crank 54 The rotation of the crank 54 causes the pivoting rods 49 on their axes 52 in the direction of the arrow F, so that the lower ends

  rods 49 move on the rod 55 to the handle

  Similarly, the lower spacer 51 exerts

  a pull on the lower cable 44, the upper spacer

  51 instead of pushing on the cable

44 corresponding.

  As a result, the flexible tubing 38 undergoes downward bending, which increases as the rotation of the crank 54 continues as well as the pull on the lower cable 44 while the upper cable 44 is released end of rotation of the crank 54, the links 49 are in their extreme position visible in Figure 5, with their lower ends abutting against the wall of the housing 59 The nozzle 5 is then oriented vertically downwards, assuming that the tubular body 24 is horizontal If the latter has an inclination on the horizontal plane, the axis of the end portion of the nozzle 5 is perpendicular

12 2527126

  to the axis X-X 'of the body 24 To return the nozzle 5 to its initial position, it is obviously carried out by rotation of

  the crank 54 in the opposite direction.

  Description of the rotary joint 25 of the lance

  shot blasting. As can be seen in FIG. 11, the end of the tubular body 24 located in the nacelle 3 is rotatably mounted about the axis of said body 24 on a fixed connection 62, integral with a tubing 63. through a ball bearing

  64 provided with two annular seals 65, 66.

  The bearing 64 and the seals 65, 66 are held on the coupling 62 by rings 67, 68 coaxial with the coupling 62, bolts such as 69 ensuring the fixing of the ring

68 on the ring 67.

  The junction between the body 24 and the ring 67 is provided by a ring 71 welded to the body 24, and sealingly applied against the ring 67. The seal 66 located on the side of the body 24 closes the bottom of an annular chamber 72 reserved between the end of the fixed connection 62 and the ring 67, this chamber 72 opening into the interior of the body

24 and the ring 71.

  Means are provided for injecting a compressed gas (preferably air) during shot blasting into the annular chamber 72, in order to constantly push back

  shot grains injected in the direction of -

  arrow G inside-the lance, which tend to penetrate inside the chamber 72 and therefore

to damage the seal 66.

  In the exemplary embodiment illustrated in FIG. 11, these means consist in an annular channel 73 formed in the ring 67 and which communicates with a bore 74 also formed therein. The channel 73 opens into the chamber 72, and a pipe 75 communicating with the piercing 74 feeds it and the channel 73 into the air

compressed during shot peening.

  Under these conditions, the compressed air constantly coming out of the chamber 72 delivers the shot grains towards the body 24, which avoids any risk of damage to the seal 66 or even, if appropriate, of the bearing 64 by the

shot grains.

  However, in this mode of injection of the compressed air, the supply-compressed air pipe 75 is integral with a rotating part, namely the ring 67 which in fact rotates solidly with the body 24, which constitutes A disadvantage The latter can be overcome by arranging, according to an advantageous variant, the injection channel of the compressed air transversely in the tubing 63, then longitudinally in the fixed connection 62, until it opens into the chamber 72. compressed air supply is then solidarisée with

the tubing 63 fixed in rotation.

  The turbine protecting the glass opening 11 of the pod 3 will now be described, with reference to

  more particularly in Figures 9 and 10.

  The turbine 76, known per se, comprises a set of blades 77 arranged radially about an axis 78 fixed to the end of a support arm 79, itself secured to an electrically driven drive motor 81 so fixed known per se to the wall 4 of the nacelle, the

  c 8 tee of the shot blasting cabin The blades 77 are solid

  The angular spacing between the blades 77 and their rotational speed are determined in correlation with the mean speed of the grains of a rotary bearing 82, mounted coaxially on the axis 78 with rolling interposition 83. shot to the window 11, so that these grains are struck and returned by the blades 77 before they could reach the

  11 In practice, a few grains are still

  less to glass 11, but in extremely low percentage relative to the total mass of shot rebounds). As an indicative numerical example, for an average speed of shot grains in rebounds of the order of 40 m / s can be used a turbine whose blades have an angular difference of 24 degrees, a width of 40 mm

  and a rotation speed of about 4000 rpm.

  Finally, the shot blasting system referred to by the invention comprises (FIG. 2) a plate 84 for receiving the piece 2 to be blasted, rotatably mounted

  around a vertical axis on a carriage 85 movable horizontally

  The tray 84 is provided at its periphery with

  86, constituted by vertical plates sie Imezm under the plate 84, and arranged at equal angular intervals. When the jet of shot is directed on a fin 86, the plate 84 is rotated about its axis and consequently the piece to be blasted, the entire surface of which can thus be exposed to the shot jets.

  after a complete rotation of 3600.

  The lance 1 is equipped with at least one projection

  tor (not shown), known per se, which illuminates

  manence the work area The light from this projector is chosen to allow the operator to see through the cloud of dust caused by the cleaning of the room.

  The operation of the grenaille-

  the purpose of the invention clearly results from the

  The operator can control the position of the end of the spray nozzle 5 in relation to the piece to be blasted according to several parameters on which it can act successively or simultaneously, in order to reach all parts of the room The operator can thus raise and lower the nacelle 3 by controlling the drive motor 23 thereof by means known per se and not shown; it can slide the lance 1 axially through the wall 4 by exerting a thrust on the handwheel 9; it can also rotate the lance 1 about its axis through the rotary joint 25, tilt the lance in a vertical plane by means of the electric cylinder 36, the

  rotate inside a cone as shown below.

  above, and finally tilt the nozzle 5 until

  pendicular with the axis of the rigid body 24.

  The blasting installation according to the invention

  tion has the following advantages.

  In the first place, the nacelle allows the opera-

  from the outside of the grenaille-lage cabin all shot blasting operations on

  This eliminates the arduousness of the operations

  hand-held helmets, avoids the operator to breathe air polluted by dust, and protects him from the noise caused by

shot blasting.

  In addition, the operator is protected from the rebounds of the shot on the workpiece, and can work sitting on the seat 12, without a suit, helmet or

protective gloves.

  The electric jack 36 relieves the operator of the weight of the lance, which he can control effortlessly

  moving in a vertical plane On the other hand,

  the operator must manually operate the communication device.

  Mande 45 of the lance rotating on itself, by maneuvering 1 6

crank 54.

  Being able to tilt the ending part

  The flexible lance 5 of the lance 1 with respect to the axis X-X 'of the lance in a plane perpendicular to this axis gives the shot jet an essential degree of freedom, which makes it possible to completely treat the entire surface.

of the room.

  The turbine 76 operating continuously during shot blasting, in the immediate vicinity of the pane 11, protects it against bouncing grain and thus prevents its plucking, which required periodically changing the glass with the previous installations, or at least to clean it, which is

  an important advantage of the invention.

  Finally, as already indicated, the permanent injection of a ring of compressed gas in the rotary joint eliminates the risk of deterioration of the seal 66 and, if appropriate, of the bearing 64 by bouncing shots. The invention is not limited to the embodiments described above and may have many variants of execution. Thus, it is obvious that more than two cables could be provided such as 44 to incline the flexible nozzle 5. even, these cables can be replaced by a jack articulated on the flexible tubing 38 and carried by the rigid body 24 I 1 is also possible to perform the bending of the flexible tubing by fixing on it a controlled sleeve of the pod 3 by a cfble The installation

  may be equipped with cylinders or additional electric motors

  to assist high-speed movements or-

  at large amplitude of the lance, that is to say axially

and angularly from the bottom up.

  In case you have to blast repetitive pieces or series of important pieces, you can program the following movements of the lance in a

  predetermined cycle, thus transforming this system

  mechanized and motorized pulverizer in an automatic robot

  computer-controlled shot blasting.

Claims (1)

1 Apparatus for blasting pieces of any shape comprising a steerable lance (1) capable of projecting a grenaillemontée jet onto a mobile platform (3) support, which can receive an operator (7) and which has a vertical wall (4) ) pierced by a glazed opening (11), characterized in that, in combination, the nacelle (3) is displaceable vertically on a support frame (13), the lance (1) comprises a terrminal nozzle ( 5) for projecting the shot articulated on a tubular body (24) of the lance (1) to allow a proper orientation of the shot jet, the body (24) of the lance (1) is slidably mounted to through the vertical wall (4) of the nacelle (3), and a turbine (76) for protection against the bouncing of shots from the window closing the opening (11) for observation of the wall (4) is subject to this last. 2 Installation according to claim 1, characterized in that the tubular body (24) of the lance (1) is rotatably mounted about its axis (X-X ') on - a connection (62) fixed in rotation located from the c 8 of the operator with respect to the wall (4) of the nacelle (3), by means of a bearing (64) provided with tench seals (65, 66) of which the one closes the bottom of an annular chamber (72) opening into the interior of the rotating body (24) and the fixed connection (62), and means are provided for injecting compressed gas during shot blasting into the annular chamber (72) to constantly push out the shot grains tending to penetrate into this chamber and to damage the seal (66). 3 Installation according to claim 2, characterized in that the compressed gas is injected into the annular chamber (72) by a duct formed either in a ring (67) for holding the bearing (64) and joints ( 65,66) integral with the rotating body (24) or in the fixed connection (62). 4 Installation according to one of claims I to 3, characterized in that the nacelle (3) is suspended from a flexible vertical curtain (16) carried by the frame (13) and whose ends can be wound and unwind simultaneously around axes (21,22), one of which is coupled to a driving motor (23) entralnement, and the sides of the nacelle (3) are guided by vertical rails (14) of the frame (13). Installation according to one of claims 1 to 4, characterized in that the nacelle is equipped with a jack (36), preferably electric, supporting the lance (1) and for orienting the latter in a plane vertical. 6 Installation according to one of claims 1 to 5, characterized in that the turbine (76) comprises blades (77), the angular difference and the rotational speed are determined in correlation with the average speed of the shot grains shot to the window (11), so that these grains are struck and returned by the blades (77) before they can reach the window (11) 7 Installation according to one of claims 1 to 6, characterized in that the projection nozzle (5) comprises a flexible tubular (38), one end of which is fixed to the tubular body (24), and this tubing can be folded in a vertical plane to a position substantially perpendicular to the axis (X-X ') of the body (24) of the lance (1) by a device (45) operable from the nacelle (3) by the operator (7). 8 Installation according to claim (7), characterized in that the device (45) for operating the flexible nozzle (5) comprises at least two cables (44) diametrically opposite on either side of the nozzle (5). ), extending along the latter and the tubular body (24), fixed at their ends to the end portion (41) of the nozzle (5) and of which these opposite ends (44 a), located in the nacelle (3) can be actuated by control means, and cables (44) are secured to the flexible nozzle (38) of the nozzle (5) by suitable members such as clamps (46) distributed intervals around the tubing (38) and held by screws. 9 Apparatus according to claim 8, characterized in that the cable control means (44) comprise two rods (49) arranged on each side of the tubular body (24) of the lance (1), made solid by spacers ('51) and articulated rotatively on pins (52) supported by the body (24), the spacers (51) being secured to the ends (44a) of the cables (44) so that the pivoting of the biellet - Tees (49) on their axes (52) causes a pull on a cable (44) and a push on the other cable (44) which causes a bending of the flexible nozzle (5), and the tilting of the rods (49). ) is controlled for example by means of a handle (54) fixed to a threaded rod (55) passing through a connecting piece (56) between the rods (49). Installation according to one of the claims   1 to 9, comprising a plate (84) for receiving the piece (2) to be blasted, rotatably mounted about a vertical axis on a carriage (85) movable horizontally, characterized in that the plate (84) is provided with winglets (86) preferably disposed vertically at its periphery, and capable of pivoting the plate (84) when the lee of them at   less is exposed to the shot blast.