The invention relates to a nozzle for compressed air to control a jet of compressed air. The invention in particular concerns a nozzle for compressed air, creating a swirling and sweeping jet of compressed air.

A compressed-air jet is typically used for e.g. cleaning, moving material, and carrying out process activities. The jet is controlled by various nozzles whose shaping aims to achieve a suitable form for the jet for any situation. Conventional nozzles are fixed and simple in structures, which does not lead to an adequately good form for the jet. This results in having to increase the duration, amount and/or pressure of the air stream to achieve the desired effect, which contributes to adding to the cost of using compressed air, which is high to begin with.

A stream of compressed air through small cross sections, such as small nozzles, is laminar as concerns its physical nature, that is, steady even at high rates of the air stream, which for its part is due to the low kinematic viscosity of air. As a result, conventional fixed nozzles do not very easily achieve a turbulent, or swirling, air stream. If a fixed nozzle is formed to generate more swirl by e.g. choking or increasing the air stream, the result is higher pressure losses, which increase the cost of compressed air.

When a hand-held compressed-air gun is used e.g. to clean surfaces, sweeping motions aim to move material out of the places being cleaned. In such a case, the goal is to boost the effect of the laminal jet coming out of the nozzle by rotating and back-and-forth motions of the hand, which adds to the stress of such work.

The compressed-air nozzle of the invention creates a swirling air stream even at low rates of the stream of air. This lead to lower consumption of compressed air, with less strain and wear on nozzle members, whereby the costs of producing compressed air also decrease. The invention allows a desired form and

turbulence for the air stream by means of shaping the members of the nozzle.

The inventive compressed-air nozzle consists of a body, fixed nozzle, rotating nozzle, turbine part, and bearing. The body includes a compressed-air connection and air channels running from the compressed-air connection through the body. The fixed nozzle is adapted on the body by a joint member, such as a thread or another mechanical coupling. Adapted running through the fixed nozzle, there are channels through which compressed air is led. The rotating nozzle is adapted to rotate within the fixed nozzle by means of a bearing. At one end, the rotating nozzle is adapted to the fixed nozzle by a sliding fir and supported at the middle to the fixed nozzle by means of said bearing. At a first end of the rotating nozzle, a turbine part is arranged, rotating under the effect of the air stream. At a second end of the rotating nozzle, there are grooves through which the air stream exits the nozzle. The inventive compressed-air nozzle operates so that the air stream coming from the compressed-air connection is guided to rotate the turbine part which is in connection with the rotating nozzle, and the rotating nozzle which is in connection with the turbine part. The air stream is led out of the compressed-air nozzle trough the channels of the fixed nozzle. As the air stream is coming out, it runs through the grooves at the second end of the rotating nozzle, which adds to the turbulence or the air stream. At the same time, the air stream coming out increases the torque that the rotating nozzle is subjected to. The turbulent air stream assumes a conical form once released from the nozzle. This means that the air stream from a nozzle connected to a compressed-air gun may be used to sweep surfaces clean without making much extra rotating or back-and-forth movement with the hand.

By shaping internal parts of the compressed-air nozzle, the turbulence of the exiting air stream and the form of the jet may be affected. For example, by changing the pitch of the grooves at the second end of the nozzle, or other geometry thereof, jets of various form and turbulence are achieved.

The present invention removes deficiencies of prior art solutions and a

compressed-air nozzle is created, generating a jet of compressed air with the desired turbulence and form. The invention allows a compressed-air nozzle which produces a swirling air stream even at low rates of air streams. This lead to lower consumption of compressed air, with less strain and wear on nozzle members, whereby the costs of producing compressed air also decrease.

Said advantages are achieved by the compressed-air nozzle which is characterized by what is defined in the claims.

In an embodiment, the compressed-air nozzle comprises a body which comprises a plurality of mutually parallel air channels of the body, and a fixed nozzle which is immovably connected to the body and which comprises a plurality of mutually parallel air channels of the fixed nozzle. The compressed-air nozzle comprises a turbine part which is adapted to rotate in relation to the body, and a rotating nozzle which is immovably coupled to the turbine part and which comprises a plurality of grooves. At a first phase, the air stream is adapted to run along the plurality of air channels of the body to the turbine part, and at a second phase, along the plurality of the air channels of the fixed nozzle out of the turbine part, and after the air channels of the fixed nozzle out of the compressed-air nozzle through the grooves of the rotating nozzle, whereby the air stream is more turbulent than prior to the first phase.

In the following, the invention will be described in closer detail by means of preferred embodiments and with reference to the accompanying drawings.

Figure 1 is sectional side view of the structure of a compressed-air nozzle according to the invention.

Figure 2 is sectional side view of the structure of a body of the compressed-air nozzle according to the invention.

Figure 3 is sectional side view of the structure of a fixed nozzle of the compressed- air nozzle according to the invention.

Figure 4 is side view cut along line A-A of the structure of a rotating nozzle of the compressed-air nozzle according to the invention.

Figure 4a is a side view of the structure of the rotating nozzle of the compressed- air nozzle according to the invention.

Figure 4b is a side view obliquely from above of the structure of the rotating nozzle of the compressed-air nozzle according to the invention.

Figure 5 is a side view of the structure of a turbine part in connection with the rotating nozzle of the compressed-air nozzle according to the invention. Figure 5a is a side view cut along the line A-A of the structure of the turbine part in connection with the rotating nozzle of the compressed-air nozzle according to the invention.

Figure 5b shows the structure of the turbine part in connection with the rotating nozzle of the compressed-air nozzle according to the invention turned 90 degrees right from the position of Figure 5.

Figure 5c shows obliquely from above the structure of the turbine part in

connection with the rotating nozzle of the compressed-air nozzle according to the invention.

Figure 6 is a sectional side view of a bearing of the compressed-air nozzle according to the invention.

Figure 6a shows obliquely from above the structure of the bearing according to the compressed-air nozzle according to the invention

Figure 7 is an exploded view of an assembly of the compressed-air nozzle according to the invention.

Figures 1 to 7 show a compressed-air nozzle which includes a body 1 , fixed nozzle 2, rotating nozzle 3, turbine part 4, and bearing 5.

The body 1 has compressed-air connection 11 at a first end of the body and air channels 12 running through the body from the compressed-air connection 11. The compressed-air connection 11 consists of a thread to which an arm part (not shown in the drawings) of a compressed-air gun may be hooked up. There may be several air channels 12, such as 3 of them, and they are adapted to guide a stream of air on the outer periphery of an impeller 41 of a turbine 4. A second end of the body has fastening members 14 to attach a fixed nozzle 2. The second end of the body further has a recess 13 in which the turbine 4 may be adapted.

The best outer form for the body 1 is that of an axially symmetrical part with the diameter in the range 15 to 20 mm. The thread of the compressed-air connection is in the range M5 to M6.

The fixed nozzle 2 is adapted by its first end to the body by a connecting element 21 such as a thread or another mechanical joint that fits in the fastening member 14 of the body. Adapted running through the fixed nozzle, there are air channels

22 through which compressed air is led. The air channels 22, of which there are e.g. 5, lead the air stream from the turbine to a second end of the rotating nozzle 3 and at the same time to a second end of the fixed nozzle. The rotating nozzle 3 is adapted to rotate inside the fixed nozzle by means of a bearing 5 which is adapted in a bearing housing 23. At its second end, the rotating nozzle is adapted to the fixed nozzle whereby a fit, suitable from the viewpoint of the rotation of parts, is formed between an inner hole 24 of the fixed nozzle and a cylindrical surface 31 of the rotating nozzle, such as a sliding fit. At the middle, the rotating nozzle 3 is supported to the fixed nozzle bu means of the bearing 5. The bearing 5 is adapted to a bearing surface 32 of the rotating nozzle.

At a first end of the rotating nozzle, a turbine part 4 is arranged, rotating under the effect of the air stream. The turbine part 4 is adapted by its inner hole to a cylindrical end 33 of the rotating part by a torque-transmitting joint such as a crimp fit, shrink fit or glue joint, or a form-locked joint.

At a second end of the rotating nozzle, there are grooves 34 through which the air stream exits the nozzle.

The turbine part 4 includes a hub 41 adapted to an axle 33 of the rotating part.

The turbine has an impeller 42 whose blades are at an angle B in relation to the longitudinal axis of the compressed-air nozzle. If desired, the blades may also be curved.

The bearing 5 is best a roller bearing such as a slotted sealed, ball bearing or rolling-contact bearing. An inner diameter 51 of the bearing is adapted on the bearing surface 32 of the rotating part, and an outer diameter 53 is adapted to a bearing surface 23 of the fixed nozzle.

The inventive compressed-air nozzle operates by two phases so that at the first phase an air stream coming from the compressed-air connection 11 is led to rotate the turbine part 4 in connection with the rotating nozzle 3 and the rotating nozzle in connection with the turbine part. Then, at the second phase, the air stream is led along the channels 22 of the fixed nozzle out of the compressed-air nozzle. At this point, as the air stream is coming out, it runs through the grooves 34 at the second end of the rotating nozzle, which adds to the turbulence or the air stream. The turbulent air stream assumes a conical form once released from the nozzle. This means that the air stream from a nozzle connected to a compressed-air gun may be used to sweep surfaces clean without making much extra rotating or back-and- forth movement with the hand.

In an alternative embodiment, the fixed nozzle further comprises a plurality of bypass channels of the fixed nozzle, through which a parallel air stream is adapted to run straight from outside the compressed-air nozzle to the plurality of air channels of the fixed nozzle, thus entirely bypassing the turbine part and joining, in the air channels of the fixed nozzle, the air stream coming from the turbine part.

By shaping the internal parts of the compressed-air nozzle, the turbulence of the exiting air stream and the form of the jet may be affected. By changing the angle B of the turbine 4 impeller and by changing the geometry of the air channels 12 and 22, it is additionally possible to affect the torque and strain the rotating nozzle is subjected to. For example, by changing the pitch of the grooves 34 at the second end of the nozzle, or other geometry thereof, jets of various form and turbulence are achieved. By selecting a pitch between 0 and 10 degrees for the grooves, jets significantly differing in form are achieved.

The outer dimensions of the compressed-air nozzle are small. The diameter is e.g. in the range 15 to 20 mm, and the length in the range 25 to 30 mm. Because of the small size and demanding geometrical form of the parts, their manufacturing requires advanced manufacturing methods. Depending on the selected material, the manufacturing may apply e.g. additive layer manufacturing, precision casting, and other casting methods. In the manufacture of prototypes and in product development, 3D printing has been successfully applied.

The parts are assembled as follows. First, the bearing 5 is installed in the bearing surface 32 of the rotating nozzle, which is followed by installing the turbine part 4 on the axle 33 of the rotating nozzle. After this, the part assembly formed by these parts 3, 5 and 4 is installed to the fixed nozzle 2 so that the bearing 5 settles in the bearing housing 23. Finally, the body 1 and fixed nozzle 2 are installed together by means of the fastening members 14 and 21. This makes the turbine part 4 to adapt in a space formed by the recess 13 of the body 1 and a space 25 at the first end of the fixed nozzle 2.

The drawings and their disclosure are only intended to illustrate the present invention. The inventive compressed-air nozzle and its structure may vary in detail within the scope of the inventive idea of the attached claims. It is obvious for a person skilled in the art that the dimensions, technical solutions, and material choices of the invention may vary due to the purpose of use. The embodiment of the invention may vary within the scope of operating conditions, customer needs, and production methods.