AT525247B1 - Mixing nozzle for mixing a liquid with air - Google Patents

Abstract

Mixing nozzle (1) for mixing a flowing liquid with air, comprising a substantially cylindrical outer part (2) with a central, in the flow direction running first flow channel (12) having a first region (10) which tapers in the flow direction, and an adjoining second area (11) which widens in the direction of flow so that a constriction is formed in the first flow channel (12), a substantially cylindrical inner part (3) with a central second flow channel (12') running in the direction of flow , wherein the inner part (3) is arranged concentrically in the outer part (2), wherein a peripheral groove (4) and an adjoining collar (5) projecting radially outwards are provided on the outer circumference of the inner part (3), the collar ( 5) has at least one opening (6) for introducing air into the liquid, with a radial opening (9) opening in the circumferential groove (4) of the inner part (3), with the second S flow channel (12') ends in the flow direction in front of the constriction of the first flow channel (12).

Description

Description

MIXING NOZZLE FOR MIXING A LIQUID WITH AIR

The invention relates to a mixing nozzle for mixing a liquid, in particular hot water from a shower with air.

Fittings, shower systems and similar sanitary devices consume large amounts of water. Conventional shower systems in particular are a major consumer of hot water or energy in households. Therefore, mixing nozzles have already been proposed in the prior art that reduce the water consumption of conventional sanitary facilities by introducing air into a water flow and replacing a certain volume fraction of the water flow with air.

[0003] For example, DE 100 08 438 A1 discloses an aeration device in which air is added to the inflowing shower water. The water is accelerated through a funnel and decelerated again in a subsequent diffuser area. WO 2005/054591 A1 proposes a flow limiter with a mixing chamber in the shape of a truncated cone.

In order to introduce the largest possible volume fraction into a water flow, however, a strong negative pressure must be generated in the mixing nozzle. In known constructions, this is achieved by the suction effect of a Venturi nozzle, the suction effect increasing as the cross-section of the nozzle opening decreases.

However, a decreasing cross-section of the nozzle opening or a high flow rate of the liquid in the mixing nozzle results in increased fluid friction losses, which is why a very small diameter of the nozzle opening also causes an undesirably high pressure loss in the shower system.

Furthermore, there is also the problem with known systems that the air-water mixture can back up in the air openings in a calcified shower hose with high friction losses and water may escape.

The geometry of the air intake tract can also have a disadvantage in known mixing nozzles, since pressure waves can rise in the moving compressible air in the intake tract, which further lead to a pulsating flow of the air/water mixture when showering.

The object of the invention is therefore to solve these and other problems and to create a mixing nozzle in which the flow pressure loss through the mixing nozzle is as low as possible, but a large volume of air can be sucked in and the risk of back pressure in the air openings is minimized is.

The problem of reducing the pressure difference between a pipe-side inlet and a pipe-side outlet of a mixing nozzle when reducing a water volume flow and at the same time maximizing the volume flow of an air flow entering the shell side is seen as a conflict of objectives.

[0010] These and other objects are solved by a mixing nozzle having the features of the independent claim.

A mixing nozzle according to the invention is designed for mixing a liquid flowing in a direction of flow with air and comprises a substantially cylindrical outer part with a central first flow channel running in the direction of flow.

The first flow channel has a first area that tapers in the direction of flow and has an adjoining second area that widens in the direction of flow, so that a constriction is formed in the first flow channel. In particular, it can be provided that the first area is located in the first flow channel in the area of the constriction

convergently tapered and the second area divergently expanded.

Furthermore, a mixing nozzle according to the invention comprises a substantially cylindrical inner part with a central second flow channel running in the direction of flow. The inner part is arranged or can be arranged concentrically in the outer part, so that the flow channels run coaxially and merge into one another. On the outer circumference of the inner part, there is a circumferential groove and a collar that connects to it and projects radially outwards, with the collar having at least one opening for introducing air into the liquid flow. The outer part has at least one radial opening leading to the outside, the radial opening opening into the peripheral groove of the inner part. According to the invention, it is provided that the inner part is arranged in the outer part in such a way that the second flow channel ends in the flow direction in front of the constriction of the first flow channel.

By ending the second flow channel in the direction of flow before the constriction of the first flow channel, an optimized transition area from the second flow channel to the first flow channel is formed. A ring-shaped transition area is created for the meeting of the liquid flow and the introduced air, so that the liquid jet emerging from the second flow channel is closely encased by the sucked-in air. Due to the maximum flow speed at the constriction, this area has the greatest negative pressure relative to the environment and thus the strongest local suction effect.

The nozzle opening of the second flow channel is thus arranged in the flow direction in front of the smallest flow cross section of the first flow channel, so that the liquid jet after the nozzle opening of the second flow channel through the tapering shape of the first area of the first flow channel and the sucked-in air up to the constriction of the first Flow channel is further accelerated.

In the constriction of the first flow channel there is essentially a laminar and rotationally symmetrical flow, the air flow enclosing the liquid jet concentrically and in the form of a circular ring.

After the smallest flow cross-section of the first flow channel, vortices break out in the originally laminar and rotationally symmetrical layered flow, and an essentially homogeneous air/water mixture is increasingly formed along the transport direction. Due to the renewed cross-sectional increase in the widening second area, the dynamic pressure increases there again.

Thus, the mixing nozzle according to the invention can be regarded as a two-phase pressure reducer, the exiting air/water mixture being formed by a water flow entering the pipe and an air flow entering the shell. The water inlet on the pipe side is subjected to a pressure of about 2.5 to 6 bar, which is usual in the sanitary area, so that a flow, driven by the water pressure and possibly stationary, occurs in the mixing nozzle.

The distance between the constriction of the first flow channel and the end of the second flow channel, i.e. in particular from the nozzle opening of the inner part, can be less than 5 mm, preferably less than 3 mm, particularly preferably about 2 mm, in order to achieve particularly good enveloping of the liquid jet with air.

According to the invention it can be provided that the inner part can be removed from the outer part. In alternative embodiments, however, it can also be provided that the inner part is formed in one piece with the outer part.

According to the invention it can be provided that the collar of the inner part bears against the inner surface of the first flow channel of the outer part. As a result, a direct flow transition can be formed between the openings in the collar and the first flow channel. In addition, this ensures that the air sucked in from the outside only flows through the opening of the collar into the first flow channel.

[0022] Preference can be provided that the first flow channel at the transition from the first

th area to the second area is continuous and continuously curved. As a result, oscillating flows can be dampened, since such a transition has a flow-stabilizing effect.

In addition, it can be provided that the second flow channel is nozzle-shaped and the inner part has a nozzle extension extending in the direction of flow with a nozzle opening, the nozzle opening being arranged in the direction of flow before the constriction of the first flow channel. As a result, the flow channels can preferably merge into one another and the transitional volume of the two flow channels can be designed in such a way that the flow in this area is as laminar as possible.

In particular, it can be provided that the second flow channel upstream has an inlet funnel which narrows in the direction of flow and which is rounded on the inside, in particular in the shape of a circular arc. As a result, pressure losses in the water flow and the formation of turbulence can be reduced.

According to the invention it can be provided that the collar has two to ten, preferably four to eight, particularly preferably six openings arranged uniformly along the circumference of the collar.

Optionally, it can be provided that the outer part has two to six, preferably two to four, particularly preferably three radial openings arranged uniformly along the circumference of the outer part.

Furthermore, with a corresponding geometric design of the intake tract, an oscillating flow can also be established, with the air mass flow being sucked in at a speed that oscillates around an average speed. Such a flow can be prevented with a special design of the air intake tract, in particular an adapted geometry of the openings in the flange of the inner part, so that a stationary flow is achieved if necessary.

The geometry of the air intake tract means the cavity of the mixing nozzle in which unmixed air can flow during operation of the mixing nozzle - i.e. the radial openings, the circumferential groove of the inner part, the openings of the inner part, and the first flow channel, in particular the first area of the first flow channel.

According to the invention it can be provided that the total area of all openings in the collar is essentially the same size as the total area of all radial openings in the outer part. As a result, a stationary flow can be achieved during air intake or, in other words, a flow cavity, which leads to a pulsating flow in the air/water mixture, being formed in the cavity of the circumferential groove of the inner part, can be prevented.

Optionally, it can be provided that the openings of the collar are adjacent to the outer surface of the nozzle extension. As a result, the air flow can be brought as close as possible to the water jet or to the area of the strongest local suction effect, so that the air volume flow can be increased.

It can also be provided that the openings of the collar are adjacent to the inner surface of the first flow channel. In this way, the air flow can be guided into the outer part in the most streamlined manner possible, without flow breaks being formed at an additional edge and thus lower pressure losses occurring as a result of flow deflections.

It can preferably be provided that the nozzle extension has a chamfered or rounded outer edge in the area of the nozzle opening. As a result, further stalls can be prevented and the air can flow as directly as possible in the direction of the nozzle opening without major deflections, thus avoiding further pressure losses.

If necessary, it can be provided that the inner part and the outer part are connected by a press connection according to DIN 8593.

It can be provided that the outer part has an external thread and an opposite

has low internal threads, which are preferably designed as Whitworth pipe threads according to ISO 228-1.

In particular, it can be provided that the mixing nozzle is set up for mounting on a shower hose and/or for mounting on a sanitary fitting.

According to the invention it can be provided that the circumferential groove is formed up to the outer diameter of the nozzle extension. As a result, the air can be distributed evenly in the circumferential groove and identical volume flows can be achieved through the openings in the collar.

It can preferably be provided that the mixing nozzle is set up after installation between a shower hose and a sanitary fitting to reduce the original water consumption of a shower system by at least 25%, preferably from 25% to 40%, in particular by up to 55%. to reduce.

It can be provided that in the outer part a sealing body rests against the inner end face of the internal thread, so that the mixing nozzle is watertight after assembly.

According to the invention it can be provided that the inner part and the outer part comprise brass, or that the outer part and/or the inner part is electrolytically chrome-plated.

Optionally, it can be provided that the inner part has six evenly spaced openings in the collar and the outer part has three evenly spaced radial openings. As a result, a mixing nozzle can be realized which is improved both with regard to the production outlay in terms of manufacturing technology and with regard to the aerodynamic requirements.

The openings in the collar of the inner part can each have a diameter of 0.8 mm to 2.0 mm, preferably 1.0 mm to 1.4 mm, particularly preferably 1.2 mm.

The radial openings of the outer part can each have a diameter of 0.8 mm to 2.5 mm, preferably 1.0 mm to 2.0 mm, particularly preferably 1.7 mm.

The diameter of the outer part can be in the range of 10 mm to 40 mm, preferably 20 mm to 30 mm, particularly preferably about 25 mm. The length of the outer part can be in the range of 30 mm to 45 mm, preferably about 36 mm, with the length of the first flow channel preferably being about 20 mm.

The diameter of the inner part can be in the range of 5 mm to 20 mm, preferably 8 mm to 15 mm, particularly preferably about 11 mm. The length of the inner part can be in the range of 7 mm to 12 mm, preferably about 9 mm, with the second flow channel extending over the entire length of the inner part.

The diameter of the first and/or second flow channel can be in the range of 1.5 mm to 4 mm, preferably 2 mm to 3 mm, particularly preferably about 2.6 mm.

The peripheral groove can have a depth in the range of 1.5 mm to 4 mm, preferably 2 mm to 3 mm, particularly preferably about 2.5 mm. The length of the circumferential groove in the direction of flow can be approximately 1.0 mm to 3 mm, preferably 1.2 mm to 2 mm, particularly preferably approximately 1.5 mm.

According to the invention, it can be provided that the inner part and outer part are manufactured with a high surface quality, in particular with a mean roughness value of less than Ra 1.6 according to DIN 3141. As a result, a low Reynolds number can be achieved in the first flow channel, so that fewer friction losses occur in the flow.

[0048] Further features according to the invention result from the description of the exemplary embodiments, the figures and the patent claims.

The invention is explained in detail below using a non-exclusive exemplary embodiment.

1 shows the cross section through a first embodiment of an outer part of a mixing nozzle according to the invention;

Figure 2 shows section A-A of the embodiment of Figure 1;

Figure 3 shows a side view of a first embodiment of an inner part of a mixing nozzle according to the invention;

Figure 4 shows section B-B of the embodiment of Figure 3;

Figure 5 shows the cross section of a first embodiment of a mixing nozzle according to the invention;

6 shows a three-dimensional oblique view of a first embodiment of a mixing nozzle according to the invention.

1 shows the cross section through a first embodiment of an outer part 2 of a mixing nozzle 1 according to the invention. The sectioned volume body of the outer part 2 is shown hatched, with the outer part 2 in this embodiment having an internal thread and an external thread, which are only symbolically indicated by lines are shown. In this embodiment, the two threads are in the form of Whitworth pipe threads in accordance with ISO 228-1. The horizontal dashed line represents the essentially rotationally symmetrical axis of the outer part 2 and the vertical dashed line A-A represents the progression of the sectional plane of FIG.

The outer part 2 is essentially cylindrical in shape and has a circular recess which is arranged concentrically to the outer diameter of the outer part 2 and in which an inner part 3 can be arranged concentrically. In the illustrated embodiment, the recess is provided with a flat chamfer at the edge, so that an inner part 3 can be inserted into the outer part 2 without problems and without tilting.

Furthermore, the outer part 2 has three radial openings 9 in the recess, which are offset from one another by 120°, and one of the three radial openings 9 is shown in section in the lower region of FIG.

In the area of the recess, the lower opening of a further circular radial opening 9 is shown as an ellipse due to the view projection. In this embodiment, the total area of all three radial openings 9 corresponds to three times the cross-sectional area normal to the axis of such a radial opening 9.

The outer part 2 forms a central first flow channel 12, which has a first region 10, which tapers in the direction of flow, and an adjoining second region 11, which widens in the direction of flow. The first flow channel 12 extends in the flow direction from the edge of the recess to the opposite edge of the outer part 2 and is divided in this embodiment into a first area 10, a second area 11 and an area with a constant diameter. In other embodiments, no third area with a constant diameter can be provided. In the illustration shown, the transition from the first area 10 to the second area 11 is marked as a vertical dashed line and thus also clearly shows the constriction in the first flow channel 12.

Fig. 2 shows the section A-A through the outer part 2 of the embodiment of Fig. 1, wherein the plane of the radial openings 9 is cut and four concentric circles are shown. The innermost circle shows the constriction in the first flow channel 12. The second smallest circle shows the inner diameter of the outer part 2, which essentially encloses the nozzle extension 7 when the inner part 3 is inserted, and on which the openings 6 tangentially border on the outside. The second largest circle shows a diameter that corresponds to the outside diameter of the inner part 3 .

3 shows a side view of a first embodiment of an inner part 3 of a mixing nozzle 1 according to the invention. The inner part 3 is constructed essentially cylindrically and has a central second flow channel 12'. On the outer periphery, the inner part 3 has a

Circumferential groove 4 and a collar 5 delimiting the groove. In the assembled state, the radial openings 9 of the outer part 2 open into the circumferential groove 4 of the inner part 3.

On the front side, the inner part has an inlet funnel 13 and, downstream, a nozzle extension 7 with a nozzle opening 8. In this embodiment, the peripheral groove 4 extends to the outer diameter of the nozzle extension 7.

The collar 5 has six openings 6, which in this embodiment are all formed with an identical bore diameter. In this embodiment, the total area of all openings 6 in the collar 5 corresponds to six times the illustrated area of such an opening 6 . In this way, the air can flow as closely as possible to the water jet, which emerges from the nozzle opening 8 of the second flow channel 12' when the mixing nozzle 1 is in operation. In the embodiment shown, the inner part 3 comprises brass and is electrolytically chrome-plated.

4 shows section B-B of the exemplary embodiment of an inner part 3 from FIG. 3. The inner part 3 has an inlet funnel 13 in the second flow channel 12'.

Furthermore, the inner part 3 has a collar 5 and a nozzle extension 7 with a nozzle opening 8 . In this embodiment, six axial openings 6 are formed in the collar 5 and in the illustration shown, two of the six evenly arranged openings 6 are shown in section. During operation, water flows through the inner part 3 through the second flow channel 12 ′, the water entering through the inlet funnel 13 into the second flow channel 12 ′ of the inner part 3 and exiting again through the nozzle opening 8 . In this embodiment, the inlet funnel 13 is formed with a circular-arc curvature.

During operation, air enters via the cylinder jacket surface of the inner part 3 , flows through the peripheral groove 4 and finally exits axially through the openings 6 .

In other embodiments, the hollow volume of the circumferential groove 4 can form a flow cavity in which pressure waves can oscillate. By matching the total area of all openings 6 in collar 5 with the total area of all radial openings 9 in outer part 2, such an oscillation of pressure waves in circumferential groove 4 can be essentially prevented in the exemplary embodiment of FIG. In the area of the nozzle opening 8, the inner part 3 in the second flow channel 12' has an outer edge in the shape of a circular arc, so that the air can flow to the free water jet, which emerges from the nozzle opening 8, essentially without flow breaks.

5 shows the cross section of a first embodiment of a mixing nozzle 1 according to the invention, which comprises an outer part 2 and a substantially cylindrical inner part 3 arranged concentrically in the outer part 2 . The mixing nozzle 1 is flowed through in the flow direction S from left to right in the illustration shown. The inner part 3 has a central second flow channel 12' with a nozzle opening 8, a circumferential groove 4 on the outer circumference, a collar 5 with six openings 6 and a nozzle extension 7. In addition, three radial openings 9 are formed in the outer part 2 and open into the peripheral groove 4 of the inner part 3 . The outer part 2 has a central first flow channel 12 which comprises a tapering first area 10 and a subsequent widening second area 11 .

The transition from the first region 10 to the second region 11 of the first flow channel 12 is continuous and continuously curved, and in the direction of flow S the nozzle opening 8 is arranged in front of the constriction of the first flow channel 12 .

In this embodiment, in the area of the constriction in the first flow channel 12, the first area 10 tapers convergently and the second area 11 widens divergently. The openings 6 border on the inside tangentially to the diameter of the outer surface of the nozzle extension 7 .

Furthermore, the openings 6 border on the outside tangentially to that inner diameter of the outer part 2 which essentially encloses the nozzle extension 7 and where the air enters the first flow channel 12 of the outer part 2 for the first time. The second flow channel 12' has a nozzle opening 8 and a rounded outer edge in the area of the nozzle extension 7, so that

the air can flow tightly around the nozzle extension 7 towards the nozzle opening 8 . In this embodiment, the inner part 3 and the outer part 2 are connected by a press connection according to DIN 8593. In the embodiment shown, the inner part 3 and the outer part 2 are manufactured with a surface finish with a mean roughness value of less than Ra 1.6 according to DIN 3141.

6 shows a three-dimensional oblique view of a first embodiment of a mixing nozzle 1 according to the invention, which is composed of an inner part 3 and an outer part 2 . One of three uniformly arranged radial openings 9 and the mouth of the first flow channel 12 are visible in the illustration shown. The other contours are shown in dashed lines as hidden edges. In this embodiment shown, the outer part 2 comprises brass and is electrolytically chrome-plated.

The invention is not limited to the illustrated embodiment, but includes all mixing nozzles within the scope of the following patent claims.

REFERENCE MARKS

1 mixing nozzle 2 outer part 3 inner part

4 circumferential groove

5 fret

6 opening

7 nozzle extension

8 nozzle opening

9 radial opening

10 First area

11 Second area

12 First flow channel 12° Second flow channel 13 Inlet funnel

S flow direction

Claims (15)

patent claims 1. Mixing nozzle (1) for mixing a liquid flowing in a flow direction S with air, comprising a. a substantially cylindrical outer part (2) with a central first flow channel (12) running in the direction of flow, which has a first area (10) which tapers in the direction of flow and an adjoining second area (11) which extends in Flow direction widened, so that a constriction is formed in the first flow channel (12), b. a substantially cylindrical inner part (3) with a central second flow channel (12°) running in the direction of flow, wherein ji. the inner part (3) is arranged concentrically in the outer part (2), so that the flow channels (12, 12°) run coaxially and merge into one another, with il. on the outer circumference of the inner part (3) there is a circumferential groove (4) and an adjoining collar (5) which projects radially outwards, the collar (5) having at least one opening (6) for introducing air into the liquid, where c. the outer part (2) has at least one radial opening (9) leading to the outside, the radial opening (9) ending in the circumferential groove (4) of the inner part (3), characterized in that the second flow channel (12') in the direction of flow before the Constriction of the first flow channel (12) ends. 2. Mixing nozzle (1) according to claim 1, characterized in that the inner part (3) can be removed from the outer part (2). 3. Mixing nozzle (1) according to claim 1, characterized in that the inner part (3) is in one piece with the outer part (2). 4. Mixing nozzle (1) according to any one of claims 1 to 3, characterized in that the collar (5) rests against the inner surface of the first flow channel (12). 5. Mixing nozzle (1) according to any one of claims 1 to 4, characterized in that the first flow channel (12) at the transition from the first region (10) to the second region (11) is continuously curved and runs continuously. 6. Mixing nozzle (1) according to one of claims 1 to 5, characterized in that the second flow channel (12°) is nozzle-shaped and the inner part (3) has a nozzle extension (7) with a nozzle opening (8) extending in the direction of flow, the nozzle opening (8) being arranged upstream of the constriction of the first flow channel (12) in the direction of flow. 7. Mixing nozzle (1) according to claim 6, characterized in that the second flow channel (12°) has an inlet funnel (13) that narrows in the direction of flow and is rounded on the inside, in particular in the shape of a circular arc. 8. Mixing nozzle (1) according to one of Claims 1 to 7, characterized in that the collar (5) has two to ten, preferably four to eight, particularly preferably six, openings (6) arranged uniformly along the circumference of the collar (5). . 9. Mixing nozzle (1) according to one of claims 1 to 8, characterized in that the outer part (2) has two to six, preferably two to four, particularly preferably three radial openings (9) arranged uniformly along the circumference of the outer part (2). . 10. Mixing nozzle (1) according to one of claims 1 to 9, characterized in that the total area of all openings (6) in the collar (5) is essentially the same size as the total area of all radial openings (9) in the outer part (2). 11. Mixing nozzle (1) according to one of claims 1 to 10, characterized in that the openings (6) of the collar (5) adjoin the outer surface of the nozzle extension (7) and/or that the openings (6) of the collar ( 5) adjoin the inner surface of the first flow channel (12). 12. Mixing nozzle (1) according to one of claims 1 to 11, characterized in that the nozzle extension (7) has a chamfered or rounded outer edge in the area of the nozzle opening (8). 13. Mixing nozzle (1) according to any one of claims 1 to 12, characterized in that the inner part (3) and the outer part (2) are connected by a press connection according to DIN 8593. 14. Mixing nozzle (1) according to one of claims 1 to 13, characterized in that the outer part (2) has an external thread and an opposite internal thread, which are preferably designed as Whitworth pipe threads according to ISO 228-1. 15. Mixing nozzle (1) according to one of claims 1 to 14, characterized in that the mixing nozzle (1) is set up for mounting on a shower hose and/or for mounting on a sanitary fitting. 3 sheets of drawings