Spray nozzle with laminar flow characteristics

Abstract

The invention relates to an improved spray nozzle (1), in particular for a cleaning device in a vehicle, comprising at least one nozzle body (2) having at least one channel (3), the channel (3) extending between an inlet orifice (4) and an outlet orifice (5) and being provided for forming a spray jet (4) from a cleaning fluid, the channel (3) is helically twisted at least in a portion thereof adjoining the outlet orifice (5), and wherein the cleaning fluid is ejected from the outlet orifice (4) and the channel (3) is helically twisted at least in the portion thereof adjoining the outlet orifice (5).

Description

Technical Field

[0001] The invention relates to a spray nozzle according to the preamble of claim 1 . Background Art

[0002] In order to clean optical surfaces in the exterior area of ​​a vehicle (e.g. glass panes, headlights, camera lenses, etc.), cleaning liquid in the form of a spray jet is usually sprayed under pressure from one or more spray nozzles of an on-board cleaning device onto the corresponding surface. The goal is always to use the limited supply of cleaning liquid as efficiently as possible, while at the same time the cleaning device should ideally ensure reliable and constant cleaning results under all operating conditions.

[0003] It has become common to form a spray jet in a channel in a separate nozzle body, which is inserted into the housing of the spray nozzle. Outdated solutions with a circular straight channel (so-called point nozzles) produce a spray jet with a circular cross section, which has proven to be inefficient especially for elongated surfaces such as windshields. Therefore, nozzle bodies with so-called fluid oscillators have been developed, which have an oscillator channel with a very complex shape, in which a spray jet that automatically oscillates or pivots in a plane and can wet elongated surfaces is formed by skillful use of pressure pulsations and turbulence. With regard to the relevant prior art, reference is made to WO 2006049622 A1 as an example.

[0004] However, the spray pattern of such a spray jet oscillating in a plane is relatively flat or narrow, and the kinetic energy of such a turbulent spray jet is also reduced, which means that stubborn dirt cannot be removed very effectively. For optimal cleaning of larger surfaces, it is therefore known to combine such an oscillator with other, for example, point nozzles or to use a plurality of oscillator channels oriented in different planes in one spray nozzle, as is known from DE 102005038292 A1. However, such a solution leads to higher manufacturing costs and requires more installation space.

[0005] Furthermore, such oscillators react sensitively to low temperatures due to their design (the viscosity of the cleaning liquid increases), which sometimes has a significant negative effect on the complex flow conditions inside and the resulting spray jet. Summary of the invention

[0006] It is therefore an object of the present invention to propose an improved spray nozzle which, with a simplified design, efficiently achieves a stable and effective cleaning result over a wide temperature range.

[0007] According to the invention, this object is achieved by a spray nozzle having the combined features of claim 1 .

[0008] The dependent claims together with the description reveal further embodiments and developments.

[0009] The invention provides that the passage through the nozzle body is completely twisted helically or at least twisted helically in its portion adjacent to the outlet orifice. The rotational moment thus generated in the flow in the passage allows the spray jet to expand with laminar characteristics and a spray pattern or cross-section that mirrors the passage cross-section in a scaled manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The invention and its further advantages are explained in more detail below with the aid of several drawings. In the drawings:

[0011] Figure 1 A highly simplified illustration of a common jet nozzle is shown;

[0012] Figure 2 A preferred embodiment of the nozzle body is shown in a spatial representation and in longitudinal section;

[0013] Figure 3 Shown according to Figure 2 The configuration of the channel of the embodiment;

[0014] Figure 4 Shown by Figure 2 and Figure 3 The formation and characteristic performance of the jet produced by the channel;

[0015] Figure 5 The rotation of the injection jet relative to the exit orifice is shown;

[0016] Figure 6 A secondary method for calculating the spread angle of the injection jet is shown. DETAILED DESCRIPTION

[0017] Figure 1

[0018] Figure 1 Previous view ( Figure 1 a) and longitudinal section ( Figure 1 b) shows a highly simplified spray nozzle 1 as used in particular in a cleaning device for a vehicle, for example for cleaning a windshield.

[0019] A nozzle body 2 with a channel 3 is arranged in a housing 7. The channel 3 extends through the entire nozzle body 2 between an inlet orifice 4 and an outlet orifice 5. A cleaning fluid, for example a cleaning liquid, is supplied under pressure via a supply passage 9. The cleaning fluid enters the channel 3 through the inlet orifice 5, flows through the channel, and is ejected from the outlet orifice 5 in the form of a spray jet 10 in a spray direction B. In the illustrated embodiment, the channel 3 extends along a channel axis K, which also corresponds to the spray direction B or is parallel to the spray direction.

[0020] In the embodiment shown, the supply passage 9 is formed in a connection piece 8 for connecting a supply line (not shown here). However, other construction solutions for supplying the inlet orifice 4 with cleaning fluid remain equally permissible in the present invention.

[0021] In principle, it is also conceivable that the channel axis K is not generally rectilinear as shown, but may have a course deviating therefrom, for example being L-shaped. However, it is important that the channel axis K has a rectilinear course at least in the portion adjacent to the outlet orifice 5, ideally orthogonal to an imaginary surface spanned by the periphery of the outlet orifice 5.

[0022] According to the principle of the preferred embodiment shown here, the nozzle body 2 is arranged in the housing 7, in a receiving seat having spherical corresponding sealing surfaces and contact surfaces, so that the nozzle body 2 can be adjusted relative to the housing 7 around all three spatial axes (specifically the vertical axis, the transverse axis and the longitudinal axis).

[0023] In the present invention, an offset support solution for the nozzle body 2 is still permitted, as is the possibility of forming the nozzle body 2 integrally with the housing 7 .

[0024] Figure 2

[0025] Figure 2 Transparent space diagram ( Figure 2 a) and a longitudinal section through the channel axis K ( Figure 2 b) shows an optimized spherical preferred embodiment of the nozzle body 2 according to the invention.

[0026] The channel 3 turns or twists helically in its course through the nozzle body 2 while continuously tapering. This means that the channel section 6 twists along the channel course about a channel axis K, which always passes through the center of the channel section 6, wherein the channel section 6 or its area decreases continuously and proportionally along the course. This will be discussed in more detail below.

[0027] The embodiment shown shows a clockwise twist. However, the opposite twist direction is also possible.

[0028] Figure 3

[0029] Figure 3 The course of a channel through the nozzle body 2 (shown here only in a simplified manner) is shown.

[0030] from Figure 3 It can be seen from the view of FIG. 5 that the outlet opening 5 is significantly twisted in the clockwise direction relative to the inlet opening 4. This can be seen in particular from Figure 3 c's view and from Figure 3 d to understand the associated cross-section in the view.

[0031] Figure 3 The view of b shows the rear part of the nozzle body 2, wherein the inlet orifice 4 is located in the center. In the embodiment shown, the channel section 6 of the channel 3, which is optimized in particular for windshields, is formed without corners, is rounded and elongated, has a defined cross-sectional width L and a defined cross-sectional height W. The cross-sectional width L is significantly greater than the cross-sectional height W. In addition, the channel section 6 is designed to be symmetrical with respect to two orthogonal symmetry axes S1, S2 intersecting at the channel axis K. Avoiding corners in the channel section 6 contributes greatly to reducing flow losses. This cross section in the form of a flat oval corresponds approximately to, for example, a Cassini curve (Cassinischen Kurve) or a Lamésches Oval (Lamésches Oval).

[0032] Figure 3 View c shows the base body 2 in a top view with the indicated series of cross sections A, B and C. The arrows show the flow direction of the cleaning fluid.

[0033] from Figure 3 It is clear from the cross section of view d that the angular position and size of the channel cross section 6 are different at different positions (6A, 6B, 6C).

[0034] It is clear that the inlet orifice 4 is significantly larger than the outlet orifice 5 and that the channel cross section 6 decreases continuously between the two orifices. Thus, the channel 3 acts as a spoiler which increases the flow velocity and thereby also the kinetic energy of the ejected spray jet 10. As a result, the spray range and cleaning efficiency are improved and the influence of the traveling airflow is reduced.

[0035] Although the contour of the channel cross section 6 is twisted about the channel axis K, it does not change along its course but is merely scaled. The contour of the outlet opening 5 thus corresponds to the reduced contour of the inlet opening 4 and overall to the contour of the channel cross section 6 .

[0036] The invention is not limited to a profile of the channel cross section 6 that scales along the channel course. In further embodiments (not explicitly shown here), the ratio of the cross-sectional height to the cross-sectional width W / L at the inlet opening 4 may also be greater than the ratio of the cross-sectional height to the cross-sectional width at the outlet opening 5, wherein the area of ​​the channel cross section 6 decreases continuously from the inlet opening 4 toward the outlet opening 5. With such a channel 3, the effect as a spoiler is maintained, wherein, due to the smaller flatness of the inflow area, the pressure losses and the flow resistance are even smaller compared to the embodiment shown.

[0037] It is also obvious that the inlet opening 5 can be designed to optimize the flow without sharp edges, but instead with a rounded or funnel-shaped mouth area, for example Figure 2 shown.

[0038] The nozzle body 2 for the cleaning system is usually made of thermoplastic by injection molding in a suitable injection molding tool. The taper of the channel 3 along its course also simplifies the manufacture of the nozzle body 2, because the taper acts as a kind of demoulding slope and helps to remove the nozzle body from the injection molding tool.

[0039] Figure 4

[0040] Figure 4 The spiral channel 3 is shown to shape or influence the spray jet 10. The nozzle body 2 is as Figure 3 The illustration is simplified and shown in a transparent manner.

[0041] Figure 4 The view in a shows a top view of the nozzle body 2; the arrows show the flow direction of the cleaning fluid that can be supplied.

[0042] The section required for a complete revolution or twist of the channel section 6 through 360° corresponds to the pitch P. The channel section 6 does not necessarily have to make a complete revolution along the channel path. It is assumed that a total twist of the channel section 6 of between 90° and approximately 180° is practically relevant, wherein it is understood that deviations from these values ​​are still permissible in the present invention.

[0043] Figure 4 The view in b intuitively shows the formation of the injection jet 10.

[0044] The cleaning fluid enters the channel 3 through the inlet orifice 4 under pressure and flows through the channel in the form of a laminar flow. Due to the helical shape of the channel 6 twisted about the channel axis K, the flow in the channel is given a rotational component in addition to the translational component. The cleaning fluid leaves the channel 3 through the outlet orifice 5, wherein the direction at each point of the outlet orifice 5 is tangential to the instantaneous flow direction of the cleaning fluid. This enables the formation of a spray jet 10, which expands constantly at an expansion angle A. The laminar flow characteristics are maintained in the process.

[0045] As already indicated above, the ratio of the cross-sectional height W to the cross-sectional width L remains constant along the entire helically twisted channel 3 .

[0046] Figure 4 c shows a side view of the spray jet 10 incident on the surface 12, and Figure 4 d shows the corresponding top view. It is noted that, by the described profile of the channel section 6, the shape of the wetted impact area 11 on the surface 12 is very favorable for the windshield. Thus, in a suitable design, even a single spray nozzle according to the invention is sufficient to clean the entire windshield, wherein the cost and installation effort of the cleaning device will be significantly reduced.

[0047] Figure 4 The view of e shows a vertical front view of the channel section 6 shortly before the incident on the surface 12. Due to the laminar flow characteristics, all sections spaced apart from each other in both the channel 3 and the injection jet 10 remain proportional to each other and correspond to each other in scaled form. The following equation always applies:

[0048]

[0049] Figure 5

[0050] The cross section or spray pattern of the injection jet 10 corresponds to the scaled channel cross section 6 as already described above, but due to the tangential spraying direction is twisted by a twist angle V about the channel axis K relative to the outlet orifice 5 in the impact region 11 . Figure 5 This effect is demonstrated using the example of a particularly practically optimized design with a twist angle V of 90°.

[0051] The twist angle V is substantially proportional to the pitch P of the channels 3. However, in practice, due to specific flow effects, deviations of about 10% to 20% are to be expected, which reduce the actual twist angle compared to its theoretical design.

[0052] Figure 6

[0053] The theoretical opening angle or spread angle A of the injection jet 10 can be easily derived from the known cross-sectional width L and the pitch P according to the following formula:

[0054]

[0055] In practice, the actual spread angle A may deviate from the theoretical value, but the deviation is usually very small.

[0056] The above-mentioned construction principle of the spiral channel according to the present invention is not limited to the above-mentioned application example of the spray nozzle for vehicle-mounted cleaning equipment, and can also be used in application scenarios such as in industry or other fields when fluids, especially liquids, are to be distributed with a defined spray pattern and laminar flow characteristics.

[0057] List of reference numerals:

[0058] 1 Spray nozzle

[0059] 2 Nozzle body

[0060] 3 channels

[0061] 4 Inlet port

[0062] 5 Outlet orifice

[0063] 6 Channel Cross Section

[0064] 7 Housing

[0065] 8 Connectors

[0066] 9 Supply Channels

[0067] 10 Jet

[0068] 11. Incident area

[0069] 12 Surface

[0070] A Expansion Angle

[0071] B Spray direction

[0072] K channel axis

[0073] L Section width

[0074] P Pitch

[0075] S Axis of symmetry

[0076] V twist angle

[0077] W Section height

Claims

1. A spray nozzle (1) for a cleaning device, in particular for use in a vehicle, comprising at least one nozzle body (2) having at least one channel (3), wherein: The channel (3) extends between an inlet opening (4) and an outlet opening (5) and is arranged to form a spray jet (4) from a cleaning fluid, which is ejected from the outlet opening (4), characterized in that the channel (3) is twisted helically at least in its portion adjacent to the outlet opening (5).

2. The spray nozzle (1) according to claim 1, characterized in that The channel (3) twists helically along the channel axis (K) with a defined pitch (P).

3. The spray nozzle (1) according to claim 1 or 2, characterized in that The channel cross section (6) of the channel (3) is elongated, having a defined cross-sectional width (L) and a defined cross-sectional height (W), wherein the cross-sectional width (L) is greater than the cross-sectional height (W).

4. The spray nozzle (1) according to claim 3, characterized in that The ratio of the cross-sectional height to the cross-sectional width (W / L) is constant in the region of the helically twisted portion of the channel (3).

5. The spray nozzle (1) according to claim 3, characterized in that The ratio of the cross-sectional height to the cross-sectional width (W / L) is greater at the inlet orifice (4) than at the outlet orifice (5).

6. The spray nozzle (1) according to at least one of claims 3 to 5, characterized in that The area of ​​the channel cross section (6) is larger at the inlet orifice (4) than at the outlet orifice (5).

7. The spray nozzle (1) according to claim 6, characterized in that The area of ​​the channel cross section (6) decreases continuously in the region of the helically twisted portion of the channel (3) in the direction of the outlet opening (5).

8. The spray nozzle (1) according to at least one of claims 3 to 7, characterized in that The channel cross section (6) is rounded, has no corners, has two orthogonal axes of symmetry (S1, S2), and is in particular substantially a Cassini curve or a flat oval or substantially a Lamé oval.

9. The spray nozzle (1) according to at least one of the preceding claims, characterized in that The nozzle body (2) is arranged in a housing (7) and is adjustable relative to at least one spatial axis.

10. The spray nozzle (1) according to claim 9, characterized in that The nozzle body (2) is arranged to be adjustable relative to the housing (7).

11. A cleaning device comprising at least one spray nozzle (1) according to at least one of the preceding claims.

Images