High-versatility device for cleaning surface by means of a liquid jet

A device for cleaning surfaces in general by means of a liquid jet comprises a cleaning liquid entry duct (1) in which a hollow shaft (3) fitted with a drive impeller (9) is rotatably mounted. After traversing the impeller, the liquid enters the shaft to then exit in the form of a compact filiform jet through a nozzle (6) which is inclined to the longitudinal axis of rotation of the shaft. The speed of rotation of the shaft and hence of the jet can be adjusted at will from zero to a maximum value by a braking unit (23, 24). There is also provided a selector (88) arranged to assume a first position in which it enables all the liquid to enter the hollow shaft, and a second position in which part of the liquid is deviated upstream of the impeller and discharged downstream of the impeller as an atomized conical jet.

SUMMARY OF THE INVENTION 
The present invention relates to a device for cleaning surfaces by means of 
a high-speed water jet. 
In this type of device, for a given available power, the jet efficiency is 
proportional to its speed, and this is obtained at the expense of the jet 
cross-section being a maximum when the jet assumes a filiform 
configuration. 
This creates a drawback in terms of the smallness of the surface covered by 
the jet, this drawback being remedied in known devices by using inclined 
nozzles which rotate at high speed and by which the jet travels through a 
conical surface and basically reproduces circumferences on the surface to 
be cleaned. However because of the tendency of the jet to atomize on 
contact with the air, a tendency aggravated by the fact that the jet 
rotates, the known methods only rarely enable sufficient efficiency to be 
obtained at the desired distance. 
This gives rise to the requirement of being able to infinitely adjust at 
least the rotational speed of the jet. A further drawback of known 
delivery devices is that they have only one delivery mode, i.e. with a 
nozzle of small cross-section and a high-speed jet. This delivery mode 
involves high pressure, which makes it impossible for the ejector to 
operate as a venturi tube through which the detergent is mixed. This 
results in a requirement for delivery devices which can operate both at 
high pressure, with small cross-section nozzles, and at low pressure, with 
larger cross-section nozzles, and which can be switched from one operating 
mode to another by a simple action on the device. The present application 
provides a high-versatility device which is able to deliver both a 
filiform jet rotating at a speed adjustable from zero to a maximum value, 
and an atomized conical jet of greater cross-section. 
To this end the device comprises, rotatably mounted on a water feed duct, a 
shaft provided at its end with an inclined nozzle and at its base with a 
bladed impeller traversed by the water, and an infinitely adjustable 
centrifugal brake, for example of the ball type, provided on said shaft in 
an intermediate position. 
According to the present invention the aforesaid system is contained in a 
sleeve which forms with the shaft an interspace through which all or part 
of the flow can be bypassed in order to be delivered concentrically to 
said rotatable nozzle. 
Finally according to the present invention said outer sleeve can be moved 
axially to the shaft, by which said bypass is made to progressively open 
or close, and also be turned about the shaft, by which the centrifugal 
brake is made to progressively engage or disengage. 
The centrifugal brake is in the form of a series of balls or rollers housed 
in respective transverse seats which rotate rigidly with the shaft, and 
are urged by centrifugal force against an outer annular track. This latter 
can be adjusted longitudinally relative to the shaft, and comprises 
roughness the degree of which increases when moving from one end to the 
other, so that the resistance offered to the rotary motion of the balls 
depends on the position occupied by the annular track. A locking member is 
also provided fixed to the rotatable shaft and arranged to engage with the 
annular track to halt the rotation of the hollow shaft and thus the jet, 
and therefore to keep the jet orientated in the desired direction.

DETAILED DESCRIPTION OF THE INVENTION 
FIGS. 1 to 6, and in particular FIGS. 1 and 2, show a hollow cylindrical 
member 1 forming the entry duct for the cleaning liquid, such as water or 
water mixed with detergents. The member 1 is intended to be connected to a 
pressurised liquid source, such as a fixed or portable pump, or piston or 
other type of similar device. With reference to the operating position 
shown in FIG. 1, at its exit from the member 1 the liquid enters rotatable 
hollow shaft 3, to the base of which there is fixed the impeller 9 of a 
turbine 2, which is traversed by the water flow. 
By way of a thrust bearing 4 the shaft 3 is mounted in a support socket 5 
which is screwed onto the downstream end of the member 1. After traversing 
the hollow shaft 3, the liquid enters a nozzle 6, from which it emerges at 
high speed as a compact filiform jet. As can be seen, the nozzle 6 is 
inclined to the longitudinal axis of the hollow shaft 3, and is housed in 
a head 7 fixed onto the downstream end of the amount of shaft. In the 
illustrated case said inclination is about 4 degrees, between said nozzle 
6 and shaft 3 there being interposed a member 8 with its cross-section in 
the form of a right cross (see FIG. 4), the purpose of which is to 
straighten the fluid threads in transit. With further reference to FIG. 1, 
the turbine 2 for driving the hollow shaft 3 comprises a bladed impeller 9 
which is fixed onto the upstream end of the shaft 3, and is struck by the 
liquid leaving a stator 10, which is locked within the member 1. The 
stator 10 comprises a central nose and a circumferential series of 
equiorientated equidistant inclined passages, the inclination of which 
opposes that of the blades of the impeller 9. An aperture 12 is provided 
diametrically in the shaft 3 to open into the axial cavity of the latter. 
The aperture 12 collects the water which has passed through the impeller. 
Finally, it should be noted that the stator 10 is fixed by an annular 
member 13 which is inserted in a fluid-tight manner into the member 1 and 
is traversed in a fluid-tight manner by the shaft 3. In addition, the 
annular member 13 is fixed by a ring 14, which is clamped against the 
upstream end of the member 1 by the said support socket 5. 
According to the present invention the elements heretofore described enable 
the device, when in the configuration shown in FIG. 1, to generate a 
compact rotating filiform jet which sweeps a conical surface having its 
origin in the nozzle 6. It is apparent that the rotational speed of the 
shaft 3 and hence of the jet depends inter alia on the pressure and flow 
rate of the entering liquid. By way of example, in tests carried out with 
a model according to the present invention, a rotating speed of the 
filiform jet of more than 10,000 r.p.m. was attained when the operating 
pressure was 60-70 atm. 
According to the present invention the speed at which the filiform jet 
rotates can be adjusted by the means described hereinafter, to values of 
the order of 1000-2000 r.p.m. 
With reference to FIGS. 1, 2 and 3 said means comprise a bushing 15 
provided with at least two outer longitudinal ribs 16 which are received 
in corresponding longitudinal channels 17 provided in the inner surface of 
an outer sleeve 18. As can be seen, this outer sleeve encloses all the 
previously described elements and is provided on its downstream end with a 
nosepiece 19 tapered toward the center to form a mouthpiece 20. 
The mouthpiece 20 is not struck by the filiform jet leaving the nozzle 6. 
However it has been found that the action of the jet as it rotates and 
skims the mouthpiece 20 creates a sucking action which causes any water 
which may have seeped into the zone surrounding the nozzle to be drawn 
out. It should be also noted that the grooves 17 in the sleeve 18 are 
torsionally but not axially engaged with the ribs 16 of the bushing 15. In 
addition, the number of grooves 17 is greater than the number of ribs 16 
(see FIG. 4) for the reasons given hereinafter. 
From FIGS. 1 and 2 it can be seen that the bushing 15 is provided 
internally with an intermediate threaded portion which is engaged by a 
corresponding thread 21 provided on the socket 5. 
The upstream end of the bushing 15 is divided into sectors by a 
circumferential series of longitudinal cuts, each sector being provided 
with an inner terminal tooth 22 arranged to act as a limit stop for the 
forward movement of the bushing 15 (see FIG. 2). In addition, the threaded 
portion of the bushing acts of a limit stop for its rearward movement as 
shown in FIG. 4. Downstream of said inner threaded portion there is 
provided inside the bushing 15 a cylindrical surface, a 
downstream-situated portion of which is perfectly smooth, while its 
remaining upstream portion is provided with a circumferential series of 
small equidistant longitudinal projections 23. As can be seen in FIG. 3, 
these projections have a convex-arched transverse shape and their 
downstream ends (see FIGS. 1 and 2) are connected to said perfectly smooth 
portion by respective inclined planes. 
The two inner surface portions of the bushing 15 form a rolling track for 
two balls 24 which are freely inserted into respective transverse cavities 
25 provided on a disc 26. The disc is torsionally engaged with the head 7 
by a prismatic fit, and is axially locked, as illustrated. It can also be 
seen from FIGS. 1, 2 and 4 that on the downstream end of the disc 26 there 
is provided an outer circumferential series of equidistant radial tongues 
27 which are inclined in the downstream direction and are elastically 
deformable. The free ends of the tongues 27 lie along an ideal 
circumference of diameter greater than the inner diameter of the smooth 
portion of the bushing 15 (see FIGS. 1, 4). 
Starting from the operating position shown in FIG. 1, in order to adjust 
(reduce) the speed at which the filiform jet rotates it is necessary only 
to rotate the sleeve 18, which then rotates the bushing 15. Because of its 
threaded engagement with the support 5, the bush 15 moves downstream as it 
rotates. This means that the resistance offered to the balls by the 
projections 23 continuously increases with simultaneous reduction in the 
speed with which the shaft 3 rotates. On continuing to turn the sleeve 18, 
at a certain point the braking effect of the projections 23 is increased 
by the friction action of the tongues 27. Finally, when the bushing 15 
mounts these latter to deform them, the hollow shaft 3 stops. After this, 
the bushing 15 can still be rotated through at least one complete 
revolution to enable the now stationary inclined filiform jet to be moved 
into the desired angular position relative to the longitudinal axis of the 
device. This can be seen from FIG. 1. 
The reverse procedure is carried out to release the shaft 3 and increase 
its speed of rotation up to its maximum value, as stated heretofore. 
Finally, it is possible to pass from the configuration of FIG. 1 (compact 
filiform jet) to the configuration of FIG. 2 (atomized conical jet) 
whatever the degree of adjustment of the braking unit. To do this it is 
neceassary merely to push the sleeve 18 in a downstream direction by which 
most of the liquid flow enters a bypass ducting which will now be 
described. The ducting consists of an annular chamber 28 lying between the 
sleeve 18 and the member 1, the free grooves 17 of said sleeve 18, and the 
nosepiece 19 of the sleeve. In addition, on the upstream end of the member 
1 there is slidingly mounted, in a fluid-tight manner, a selector bush 88 
which is received in a fluid-tight manner in the sleeve 18. Said selector 
bushing 88 is provided with a circumferential ledge 29 which lies between 
the upstream ends of the projections defining the grooves 17 in the sleeve 
18, and a retention ring 30 removably fitted into the mouth of said sleeve 
18. When this latter is moved downstream as stated, the through holes 31 
provided in the bushing 88 communicate with the through holes 32 provided 
in the member 1 upstream of the stator 10. As stated, in this 
configuration most of the liquid reaches the nosepiece 19 without 
traversing the impeller 9. In addition, before reaching the nosepiece 19 
the liquid traverses a ring 33 embracing the head 7 (see FIG. 2), which is 
clamped between the sleeve 18 and the nosepiece 19. Finally, as can be 
best seen in FIGS. 5 and 6, the ring is provided with a circumferential 
series of equiorientated and equidistant inclined apertures 34. As the 
bypassing liquid traverses the apertures 34 it is subjected to a screwing 
movement which enables it to expand beyond the mouthpiece 20 in the form 
of an atomized conical jet which also contains that part of the liquid 
emerging from the nozzle 6. 
Lastly, the advantage should be noted deriving from the fact that the 
operating position of the device shown in FIG. 2 cannot be changed by the 
effect of the liquid penetrating into the nosepiece 19. This avoids the 
risk of the device passing accidentally from the low speed atomized 
conical jet condition to the high speed filiform jet condition, with its 
easily imaginable consequences. 
FIGS. 7 and 8 illustrate a different embodiment of the invention, in which 
those parts common with the embodiment shown in FIGS. 1 to 6 are 
identified by the same reference numerals. 
Again in this embodiment the hollow member 1 comprises a thread 110 for 
fixing it to the end of the pipe feeding the pressurised water. 
In this embodiment, the member 1 comprises a baffle 90 downstream of the 
radial holes 32 and a tangentially inclined hole 320 downstream of the 
baffle 90. The baffle 90 and annular member 13 define the chamber in which 
the impeller 9 rotates, driven by the water entering through the hole 320. 
To the downstream end of the hollow member 1 there is screwed a socket 5 
with which there is engaged by a male-female threaded engagement, a 
bushing 15 which extends beyond the end of the member 1. Said bushing 15 
comprises a series of equidistant inner longitudinal projections 23 having 
an arched, transverse shape and tapered downstream ends. In that part of 
the bushing 15 provided with projections there is received a member 26 
rigid with the head 7 which rotates with the shaft 3. 
The member 26 comprises a series of radial cavities 25 housing the rollers 
240 (FIG. 8). 
In addition, immediately downstream of said radial cavities the member 26 
carries a rubber ring 260 lying in front of the tapered part of the 
projections 23. 
The member 26 is cup-shaped downstream and is provided with inclined outer 
channels 261 the purpose of which will be apparent hereinafter. On the 
upstream end of the member 1 there is slidingly mounted, in a fluid-tight 
manner, a bushing 300 to which an outer sleeve 18 is fixed by means of the 
rear ring nut 301 screwed onto the outer sleeve. 
Internal to the sleeve 18 there is a tube 302 provided with a hexagonal key 
seat 303 by which it is maintained in position between bushing 300 and the 
ends of a series of parallel ribs 17 provided on the inside of the sleeve 
18, so as to follow the movements of the sleeve 18. The appendices 16 of 
the bushing 15 slidingly engage between the ribs 17 of the bushing 15. 
At is downstream end, the sleeve 18 comprises the nosepiece 19 with the 
mouthpiece 20. 
The operation of the described second embodiment of the invention is as 
follows. 
In the configuration shown in the upper part of FIG. 7 the device is 
arranged to deliver water at high pressure. 
The water enters the member 1, passes through the holes 32 and is returned 
to the interior of the member 1 through the tangential hole 320. Here it 
operates the impeller 9 and reaches the nozzle 6 through the cavity of the 
shaft 3. 
The shaft rotates together with the impeller 9, the speed of rotation being 
braked by the engagement of the rollers 240 against the projections 23. 
The braking action can be increased by turning the sleeve 18 without moving 
it axially. 
The turning of the sleeve 18 is transmitted via the ribs 17 and appendices 
16 to the bushing 15 screwed onto the socket 5. 
On undergoing suitably directed rotation, the bushing advances towards the 
left in the figure until it contacts the ring 260 via the tapered ends of 
the projections 23. 
When the bushing 15 has sufficiently advanced, it halts the rotation of the 
shaft 3, and subsequent turning of the sleeve 18 moves the shaft 3 so as 
to orientate the inclined nozzle 6 as desired. 
In the configuration illustrated in the lower part of FIG. 7, which is 
obtained by pushing the sleeve 18 forwards (towards the left), the device 
operates at low pressure. 
The water which enters the member 1 and leaves through the radial holes 32 
is fed to the outside of the tube 302 and passes through the interspace 28 
between the sleeve 18 and said tube 302 and the bushing 15. 
After being orientated by the channels 261 so that it forms a jet which 
rotates about itself, the water emerges from the mouthpiece 20 without 
undergoing throttling through the nozzle. 
A diverging low-pressure jet is formed producing a rotational impulse, as 
described. 
It should be noted that in this configuration the water pressure remains 
below the limiting value for the operation of a possible detergent ejector 
located upstream of the device. 
The merits and advantages of the present invention are apparent from the 
aforegoing and from an examination of the accompanying figures. The 
invention is not limited to the illustrated and described embodiments, but 
includes all technical equivalents to the aforesaid means and their 
combinations provided they are implemented within the context of the 
following claims.