Spray nozzle and method for operating a spray nozzle

Abstract

Spray nozzle for spraying liquids with a housing (12) having an inlet opening (14) and an outlet opening (16) for the liquid to be sprayed, wherein at least one flow path for the liquid to be sprayed is provided between the inlet opening and the outlet opening, wherein the at least one flow path is formed at least sectionally between a piston displaceable within the housing and a piston seat of the housing, wherein the piston (20) is displaceable between a spray position and a cleaning position, wherein the piston (20) and the piston seat are formed at least sectionally in a frustoconical shape, and wherein in the spray position a frustoconical section (26) of the piston rests against a frustoconical section of the piston seat, and in the cleaning position the frustoconical section of the piston is lifted away from the frustoconical section of the piston seat.

Description

[0001] The invention relates to a spray nozzle for spraying liquids, comprising a housing with an inlet opening and an outlet opening for the liquid to be sprayed, wherein at least one flow path for the liquid to be sprayed is provided between the inlet opening and the outlet opening. The invention also relates to a method for operating a spray nozzle.

[0002] The invention aims to improve a spray nozzle and a method for operating a spray nozzle.

[0003] According to the invention, a spray nozzle having the features of claim 1 and a method having the features of claim 14 are provided for this purpose. Advantageous developments of the invention are mentioned in the subclaims.

[0004] A spray nozzle for spraying liquids comprises a housing with an inlet opening and an outlet opening for the liquid to be sprayed. At least one flow path for the liquid to be sprayed is provided between the inlet opening and the outlet opening. The at least one flow path is formed, at least in sections, between a piston that can be moved within the housing and a piston seat of the housing, wherein the piston can be moved between a spraying position and a cleaning position. By allowing the piston to be moved between a spraying position and a cleaning position, it is possible to provide a flow path with a defined, desired cross-section during spraying operation and a significantly larger cross-section during cleaning operation in order to flush out any contaminants that may be present.

[0005] In a further development of the invention, the piston and the piston seat are geometrically adapted to one another and the piston seat, which tapers at least in sections in the direction of flow, and the piston lie sealingly against one another in the spray position at least in the region of a contact line.

[0006] In this way, the flow of sprayed liquid between the piston seat and the piston can be restricted to defined channel-like recesses in the piston seat and / or the piston. This ensures that all sprayed liquid flows through the channel-like recesses between the piston seat and the piston, preventing leaks outside the channel-like recesses between the piston and the piston seat.

[0007] In a further development of the invention, the piston and / or the piston seat are at least partially frustoconical, wherein in the spraying position a frustoconical section of the piston rests against a frustoconical section of the piston seat and wherein in the cleaning position the frustoconical section of the piston is lifted off the frustoconical section of the piston seat.

[0008] The provision of a piston that is at least partially truncated cone-shaped and / or a piston seat that is at least partially truncated cone-shaped makes it possible to provide a flow path with a desired cross-section in a spraying mode and a significantly larger cross-section in a cleaning mode in order to flush out any contaminants that may be present. The movement of the piston between the spraying position and the cleaning position can be brought about, for example, by changing the pressure of the liquid to be sprayed, optionally in conjunction with a spring. This makes it very easy to switch between a spraying mode and a cleaning mode. Because the piston and / or the piston seat are at least partially truncated cone-shaped, a comparatively tight fit between the piston and the piston seat can be maintained even with frequent changes between spraying mode and cleaning mode.Losses of the sprayed liquid, i.e., liquid that does not follow the intended flow path, can thus be completely avoided or significantly reduced. The spray nozzle according to the invention can thus be operated efficiently. For example, a spherical or elliptical piston can be combined with a truncated cone-shaped piston seat.

[0009] In a further development of the invention, the piston and / or the piston seat has at least one channel-like recess which forms part of the flow path in the spray position.

[0010] In this way, a very precisely defined flow path can be created. For example, the downstream end of the flow path can form an outlet opening for the liquid to be sprayed. Due to the truncated cone-shaped design of at least a portion of the piston and the piston seat, the channel-like recess can be reliably sealed during spraying operation, so that all of the liquid to be sprayed introduced into the inlet opening of the spray nozzle flows through the channel-like recess and exits the spray nozzle again at the outlet opening.

[0011] In a further development of the invention, a cross section of the channel-like depression is reduced in the flow direction at least in sections.

[0012] In this way, for example, the spray pattern and the pressure loss in the spray nozzle can be adjusted as desired.

[0013] In a further development of the invention, the at least one channel-like recess runs straight along a surface line of the frustoconical section of the piston and / or the frustoconical section of the piston seat.

[0014] In a further development of the invention, at least one channel-like recess runs helically along the truncated cone-shaped piston and / or the truncated cone-shaped piston seat.

[0015] In this way, the liquid to be sprayed can be given a swirl to create, for example, a conical jet or a hollow conical jet.

[0016] In a further development of the invention, the piston is preloaded into the cleaning position by means of a spring.

[0017] If the pressure of the liquid to be sprayed drops below a predefined value, the spring force applied by the spring is greater than the force applied to the piston by the liquid to be sprayed. As a result, the piston moves from the spray position, where the piston rests against the piston seat, to the cleaning position, where the piston is lifted from the piston seat. If the pressure of the liquid to be sprayed then increases above the predefined value, the piston moves back to the spray position, and the spray nozzle returns to spraying mode.

[0018] In a further development of the invention, the spring is arranged within the housing and, at least during spraying operation, is surrounded by the fluid to be sprayed. The arrangement of the spring within the housing enables a compact design of the spray nozzle according to the invention. Since the spring is surrounded by fluid, at least during spraying operation, contamination of the spring is largely avoided.

[0019] In a further development of the invention, the piston is spaced from an inner wall of the housing upstream of the piston seat, so that liquid to be sprayed can flow between the inner wall of the housing and the sections of the piston located upstream of the piston seat, both in the spraying position and in the cleaning position.

[0020] As a result, there is only a very slight pressure loss of the liquid to be sprayed in the housing up to the piston seat during spraying operation, and there is also no wall friction between the sections of the piston upstream of the piston seat and the inner wall of the housing, as there is no sealing element on the inflow side of the piston. As a result, there is only a single sealing point within the housing, namely the piston seat. This contributes to very reliable sealing. The fact that there is no contact between the piston and the wall significantly increases the functional reliability of the nozzle, as there is no friction and no hysteresis when the piston moves from the spray position to the cleaning position and vice versa. Friction and, consequently, hysteresis would occur if a seal were used.Liquid flowing between the piston and the inner wall of the housing reunites upstream of the piston seat with the remaining liquid to be sprayed, which is then fed to the outlet opening.

[0021] In a further development of the invention, the piston has at least one through-channel which opens upstream of the piston seat into a space between an inner wall of the housing and the piston.

[0022] The through-channel always opens above the piston seat on the housing, regardless of whether the piston is in the spraying or cleaning position. The through-channel can be easily dimensioned, for example by changing the diameter or by inserting orifices, in order to be able to adjust the amount of liquid to be sprayed flowing through the through-channel. Advantageously, the piston is spaced from an inner wall of the housing upstream of the piston seat when the piston is in the spraying position. In spraying mode, the fluid to be sprayed can therefore flow both through the through-channel of the piston and laterally past the piston. In cleaning mode, the liquid also flows both between the housing and the piston and through the through-channel of the piston.This allows any contaminants between the piston and the inner wall of the housing, as well as from the passageway in the piston and from the area of ​​the piston seat, to be flushed out when the piston is in the cleaning position. In the spray position, the fluid flowing between the housing and piston recombines with the fluid flowing through the piston upstream of the piston seat and is then fed to the outlet opening. In the case of a flat jet nozzle, the fluid flowing around the piston could strike the tongue forming the jet shape and thus conform to the spray jet.

[0023] In a further development of the invention, the housing has a baffle surface, wherein the flow path within the housing ends at the outlet opening and wherein the outlet opening and the baffle surface are arranged such that in the spray position of the piston, a liquid jet emerging from the outlet opening strikes the baffle surface.

[0024] In this way, the outlet opening can be designed to produce a solid jet. The fanning out of the solid jet into a flat jet only occurs at the impact surface. This allows the spray nozzle to be designed to be extremely resistant to clogging.

[0025] In a further development of the invention, the outlet opening in the spray position of the piston is formed by means of the truncated cone-shaped section of the piston seat and by means of the truncated cone-shaped section of the piston.

[0026] The outlet opening itself is thus enlarged in the cleaning position of the piston so that any existing contaminants can be flushed out.

[0027] In a further development of the invention, the outlet opening in the spray position of the piston is formed in sections by means of a channel-like recess in the piston and / or the piston seat.

[0028] In a further development of the invention, a swirl chamber is arranged upstream of the outlet opening in the housing. For example, a swirl can be imparted to the liquid to be sprayed by means of a channel-like recess running helically along the truncated cone-shaped piston and / or along the truncated cone-shaped piston seat. A uniform liquid or droplet distribution is then achieved in the swirl chamber, and the outlet opening is then arranged downstream of the swirl chamber. In this way, a hollow cone jet or full cone jet can be generated downstream of the outlet opening.

[0029] In a further development of the invention, the piston seat and the piston are arranged upstream of the swirl chamber.

[0030] The object underlying the invention is also achieved by a method for operating a spray nozzle, in which the setting of a first pressure of a liquid to be sprayed in a spraying operation and the setting of a second pressure of the liquid to be sprayed in a cleaning operation are provided, wherein the second pressure is lower than the first pressure.

[0031] In this way, switching between cleaning mode and spraying mode is possible by simply changing the pressure of the liquid to be sprayed. Within the scope of the invention, the first pressure and the second pressure can form a pressure range. The first pressure range then lies above the second pressure range, with no overlap between the two pressure ranges.

[0032] Further features and advantages of the invention will become apparent from the following description of preferred embodiments of the invention in conjunction with the drawings. Individual features of the various illustrated and described embodiments can be combined with one another in any way without exceeding the scope of the invention. This also applies to the combination of individual features without other individual features with which they are illustrated and / or described in connection. The drawings show: Fig. 1 a spray nozzle according to the invention according to a first embodiment from below, Fig. 2 the spray nozzle of the Fig. 1 from below at an angle from a different perspective, Fig. 3 detail C from Fig. 2 , Fig. 4 a side view of the spray nozzle Fig. 1 , Fig. 5 another side view of the spray nozzle Fig. 1 , where the spray nozzle is opposite to the illustration of the Fig. 4 was rotated 90°, Fig. 6 a sectional view of the spray nozzle of the Fig. 1 , Fig. 7 a view of the section plane AA in Fig. 6 , Fig. 8 the detail B from Fig. 6 , the Fig. 9 bis 16 the Fig. 1 bis 8 corresponding views, with a piston of the spray nozzle in the cleaning position, Fig. 17 a spray nozzle according to the invention according to a second embodiment of the invention from below, Fig. 18 the spray nozzle of the Fig. 17 from below at an angle from a different perspective, Fig. 19 detail C from Fig. 17 , Fig. 20 a side view of the spray nozzle Fig. 17 , Fig. 21 another side view of the spray nozzle Fig. 17 , where the spray nozzle is opposite to the illustration of the Fig. 20 was rotated 90°, Fig. 22 a sectional view of the spray nozzle of the Fig. 17 , Fig. 23 a view of the section plane AA in Fig. 22 , Fig. 24 the detail B from Fig. 22 , the Fig. 25 bis 31 the Fig. 17, 18, 20, 21, 22, 23 or 24 corresponding representations, whereby a piston of the spray nozzle, in contrast to the Fig. 17 bis 24 is in a cleaning position, Fig. 32 a spray nozzle according to the invention according to a third embodiment from below, Fig. 33 a side view of the spray nozzle of the Fig. 32 , Fig. 34 a sectional view of the spray nozzle of the Fig. 33 , whereby the piston of the spray nozzle is not cut, Fig. 35 a view of the section CC in Fig. 34 , Fig. 36 the detail B from Fig. 35 , Fig. 37 bis 39 the Fig. 34, 35 or 36 corresponding views, where the piston of the spray nozzle is different from the state of the Fig. 34, 35 und 36 is in the cleaning position, Fig. 40 a partially sectioned view of a spray nozzle according to a fourth embodiment, wherein the piston of the spray nozzle is not shown in section, Fig. 41 a view of the section CC in Fig. 40 , Fig. 42 the detail B from Fig. 41 , the Fig. 43, 44 und 45 the Fig. 40, 41 or 42 corresponding views, where the piston of the spray nozzle is different from the state of the Fig. 40, 41 und 42 is in the cleaning position; Fig. 46 a sectional view of a spray nozzle according to the invention according to a further embodiment, wherein the piston of the spray nozzle is in the spray position, Fig. 47 the detail D from Fig. 46 , Fig. 48 a sectional view of the spray nozzle of the Fig. 46 , with the piston of the spray nozzle in the cleaning position, and Fig. 49 the detail D from Fig. 48 .

[0033] Fig. 1 shows a spray nozzle 10 according to the invention with a housing 12. A Fig. 1 A concealed inlet opening 14 allows the liquid to be sprayed to enter the housing 12 and a Fig. 1 The outlet opening 16, which can only be seen in sections, allows the liquid to be sprayed to escape from the housing 12. The spray nozzle 10 can be attached to a supply line (not shown) for the liquid to be sprayed.

[0034] In Fig. 1 It can be seen that downstream of the outlet opening 16 a baffle 18 is provided, the upper side of which, which is in Fig. 1 is concealed and faces the outlet opening 16, forming a baffle surface for the liquid jet emerging from the outlet opening 16. The liquid jet emerges from the outlet opening 16 as a solid jet and, after impacting the baffle surface, is fanned out into a flat jet.

[0035] Fig. 2 shows the spray nozzle 10 from a different angle. The outlet opening 16 is clearly visible in this view.

[0036] Fig. 3 shows detail C from Fig. 2 enlarged. It can be seen that the outlet opening 16 has a U-shaped form and forms the end of a channel-like recess between a piston 20 and a piston seat provided on the housing 12.

[0037] Fig. 4 shows a side view of the spray nozzle 10, wherein it can be seen that the impact surface 22 is inclined on the side of the impact bar 18 facing the outlet opening 16. A flat jet is shown in the view of the Fig. 4 towards the viewer, whereby the flat jet is not aligned horizontally, but in Fig. 4 is tilted counterclockwise. If several spray nozzles 10 are arranged next to each other, this can prevent the flat jets from touching each other.

[0038] Fig. 5 shows the spray nozzle 10 in a view which is different from the illustration of the Fig. 4 rotated 90°.

[0039] Fig. 6 shows a sectional view of the spray nozzle 10 of the Fig. 1 , wherein the section plane contains the central longitudinal axis of the spray nozzle 10 and is parallel to the drawing plane of the Fig. 4 runs. Fig. 6 shows that the piston 20 inside the housing 12 is moved from the Fig. 6 The piston can be moved upwards from the spray position shown into a cleaning position. The cleaning position of the piston is in Fig. 14 The piston 20 is moved by means of a helical compression spring 24 from the Fig. 6 shown spray position into the Fig. 14 shown cleaning position pre-tensioned.

[0040] It is Fig. 6 It can be seen that the piston 20 has a frustoconical section 26 and that a frustoconical piston seat 28 is formed on the housing 12, against which the frustoconical section 26 of the piston 20 rests.

[0041] The piston seat 28 has a channel-like recess 30, see also Fig. 8 , which forms a flow path for the liquid to be sprayed in the spray position of the piston 20. The liquid to be sprayed flows as a result, see Fig. 6 , into the inlet opening 14 of the spray nozzle 10, enters a central bore 32 of the piston 20 and exits the piston 20 via a transverse bore 34. The transverse bore 34 is open on two sides. The liquid to be sprayed is then located between the housing 12 and the piston 20 in the area in which Fig. 6 the compression spring 24 can be seen. The liquid to be sprayed then enters the channel-like recess 30 in the piston seat 28, see Fig. 8 , and then exits at the end of the channel-like recess at the outlet opening 16. The liquid to be sprayed will exit as a solid jet from the outlet opening 16 and then onto the Fig. 6 to be recognized impact surface 22, which is concave, and then, as already explained, are fanned out into a flat jet.

[0042] If the spray nozzle 10 is used to spray liquids containing impurities, there is a risk that the channel-like recess 30, which forms the narrowest cross-section in the flow path through the housing 12, will become clogged with impurities. This generally adversely affects the spray pattern of the spray nozzle 10.

[0043] In order to flush out any impurities that may be present in the channel-like recess 30, the piston 20 is moved away from the Fig. 1 bis 8 shown spray position into a cleaning position, as shown in the Fig. 9 bis 16 is shown.

[0044] Based on the Fig. 14 It can be seen that the piston 20 is now relative to the housing 12 starting from the position shown in Fig. 6 This is achieved by reducing the pressure of the liquid to be sprayed, which is introduced into the inlet opening 14, until the force exerted by the liquid to be sprayed on the piston 14, which is shown in Fig. 14 downwards is smaller than the spring force exerted by the spring 24 on the piston 20 from bottom to top. As a result, the piston moves in the Fig. 14 cleaning position shown. As a result, the truncated cone-shaped section 26 of the piston is lifted from the truncated cone-shaped section 28 of the piston seat, and the channel-like recess 30 in the piston seat is now open toward the central longitudinal axis of the housing 12. The liquid to be sprayed continues to flow through the piston 20 and can thereby flush out any impurities accumulated in the channel-like recess 30, see also Fig. 16 .

[0045] After a cleaning operation in the position of the piston 20 of the Fig. 14 the channel-like recess 30 is thereby free of impurities again and the pressure of the liquid to be sprayed can be increased again until the piston 20 reaches the Fig. 6 takes the spray position shown.

[0046] The representations of the Fig. 9 bis 13 correspond to the illustrations of the spray nozzle 10 of the Fig. 1, 2, 3, 4 or 5, with the piston in the Fig. 9 bis 13 , as stated, in the cleaning position and not, as in the Fig. 1 bis 5 , is in the spray position. This difference is most clearly seen when comparing the Fig. 3 and 11 to recognize. Fig. 3 shows the piston 20 and it can also be seen that the piston 20 limits the outlet opening 16 on one side. In Fig. 11 The piston, however, is no longer visible and the outlet opening 16 is open to one side or significantly enlarged. The outlet opening 16 forms the end of the channel-like recess 30, see the Fig. 8 and 16 . In the cleaning position of the piston according to Fig. 11 the outlet opening 16 and the channel-like recess 30 can thereby be rinsed and freed from impurities, since the channel-like recess 30 and the outlet opening 16 are then open towards the central longitudinal axis of the housing 12.

[0047] Based on the Fig. 1 bis 16 It can be seen that the channel-like recess 30 in the spray nozzle 10 is provided in the piston seat 28, in other words in the housing 12.

[0048] The Fig. 17 bis 31 show different views of a spray nozzle 40 according to a further embodiment, in which the channel-like recess 60, see for example Fig. 29 , is provided in the piston 50. Otherwise, the spray nozzle 40 is largely identical to the spray nozzle 10, so that only the differences between the spray nozzle 40 and the spray nozzle 10 will be explained below.

[0049] In the state of Fig. 25 bis 31 the piston 50 is in the cleaning position, in the Fig. 17 bis 24 in the spray position.

[0050] In Fig. 17 and in Fig. 18 the underside of the piston 50 can be seen. Fig. 19 shows detail C from Fig. 17 . It is in Fig. 19 It can be seen that the channel-like recess 60 is provided in the piston 50. In the spray position of the Fig. 17 bis 24 is the channel-like depression 60, see also Fig. 22 bis 24 , thus formed by a U-shaped groove in the piston 50 and the truncated cone-shaped piston seat 28 in the housing 12. It is Fig. 24 It can be seen that a cross-section of the channel-like recess 60 tapers towards the outlet opening 46.

[0051] As with nozzle 10 of the Fig. 1 bis 16 a full jet emerges from the outlet opening 16 and then hits the baffle 22 and is thereby fanned out into a flat jet, see the Figs. 20 and 21 To move from the spray position to the Fig. 19 to 24 the piston 50 into the cleaning position of the Fig. 25 to 31 To move the piston 50, as in the case of the nozzle 10, the pressure of the liquid to be sprayed must be reduced until the spring 24 pushes the piston 50 from the position shown in Fig. 22 shown spray position into the Fig. 29 Press the cleaning position shown. In the cleaning position of the Fig. 25 to 31The channel-like recess 60 in the piston 50 is open to one side, namely to the radially outer side, so that any impurities present in the channel-like recess 60 can be flushed out. The piston 50 of the spray nozzle 40 also has a truncated cone-shaped section 26, which, see for example Fig. 24 and Fig. 31 , in the spray position rests against the also truncated cone-shaped piston seat 28.

[0052] Fig. 32 shows a spray nozzle 70 according to the invention according to a further embodiment with a housing 72. Fig. 33 shows the spray nozzle 70 in a side view.

[0053] Fig. 34 shows the spray nozzle of the Fig. 32 in a partially sectioned view. Within the housing 72, a piston 80 is arranged between a Fig. 34 to 36 shown spray position into a position in the Fig. 37 to 39The piston 80 is pre-tensioned into the cleaning position by a compression spring 24. As Fig. 35 As can be seen, the liquid to be sprayed enters the housing 72 at an inlet opening 14, then passes through a central bore in the piston 80 into a transverse bore in the piston 80 and then passes from a space between the piston 80 and the housing 72 into a channel-like recess 90 provided in the housing 72. The channel-like recess 90 is provided in a truncated cone-shaped piston seat 88 of the housing 72 and a truncated cone-shaped section 86 of the piston 80 rests against the piston seat 88 in the spray position. In the spray position of the Fig. 34 to 36 The liquid to be sprayed must therefore pass completely through the channel-like recess 90.

[0054] Downstream of the piston 80, in the housing in the spray position, the Fig. 34 to 36a swirl chamber 92 is formed. From the swirl chamber 92, the liquid to be sprayed enters a cylindrical outlet channel 94 and then enters a truncated cone-shaped extension 96 of the outlet channel 94. Downstream of the truncated cone-shaped outlet channel 96, a spray jet in the form of a hollow cone then emerges. The liquid flowing through the channel-like recess 90 is set into a rotation about the central longitudinal axis, since the channel-like recess 90 is arranged obliquely to the central longitudinal axis of the housing 72. Two channel-like recesses 90 are provided, wherein Figs. 35 and 36only one recess 90 is visible. The channel-like recesses 90 are linear, but do not converge on the central longitudinal axis of the housing 72, but are laterally offset or skewed relative to the central longitudinal axis. As a result, the liquid exiting the channel-like recesses 90 has a swirl around the central longitudinal axis. In the swirl chamber 92 and also in sections 94 and 96 of the outlet channel, the liquid to be sprayed thus rotates around the central longitudinal axis, forming a hollow cone jet. With appropriate design of the channel-like recess 90 and the swirl chamber 92, a full cone jet can also be generated.

[0055] The Fig. 37 to 39 show the spray nozzle 70 of the Fig. 32 to 36 in a cleaning operation. The pressure of the liquid at the inlet opening 14 was reduced until the spring 24 moved the piston 80 into the cleaning position of the Fig. 37upwards. The channel-like depression 90, see Fig. 38 and Fig. 39 , is thus open towards the central longitudinal axis of the housing 72 and any impurities located in the channel-like recess 90 can be flushed out.

[0056] When the fluid pressure at the inlet opening 40 increases, the piston 80 is returned to the spray position of the Fig. 34 to 36 moved.

[0057] The Fig. 40 to 45 show a further spray nozzle 100 according to the invention according to a fourth embodiment. The spray nozzle 100 is almost identical to the spray nozzle 70 of Fig. 32 to 39 constructed, so that only the differences to the spray nozzle 70 are explained.

[0058] The Fig. 40 to 42 show the spray nozzle 100 in spray mode, the Fig. 43 to 45 show the spray nozzle 100 in cleaning mode.

[0059] Fig. 40shows a partial sectional view of the spray nozzle 100. The piston 120 of the spray nozzle 100 is slidably arranged within the housing 102 and is biased by a spring 24 into the Fig. 43 to 45 shown cleaning position. The piston 120 is in Fig. 40 not shown in section and has a truncated cone-shaped section 126 which, in the spraying position of the Fig. 40 to 42 abuts a likewise frustoconical piston seat 128 in the housing 102. In all previously described embodiments, including the spray nozzle 100, the cone angle of the piston seat and the cone angle of the frustoconical section of the piston are the same. Therefore, in the spray position, in all previously described spray nozzles, the frustoconical section of the piston rests flat against the frustoconical piston seat.

[0060] The piston 120 has a channel-like recess 130 which, as in Fig. 40As can be seen, it runs helically along the frustoconical section 126 of the piston. In the spray position, a swirl chamber 132 is formed below the piston 120, and an outlet channel is provided downstream of the swirl chamber 132. The swirl chamber 132 and the outlet channel are identical to those of the spray nozzle 70 and are therefore not explained again.

[0061] In contrast to the spray nozzle 70 of the Fig. 32 to 39 For the spray nozzle 100 the Fig. 40 to 45 the channel-like recess 130 is provided in the piston 120 and not in the housing 102. Based on the illustration of the Fig. 43 It can be seen that two channel-like recesses 130 are provided on the piston 120. The first channel-like recess 130 is in Fig. 43 facing the viewer, the second channel-like depression 130 is on the Fig. 43 not visible back of the piston 120 and therefore in Fig. 43 only indicated by dashed lines.

[0062] Within the scope of the invention, one or more channel-like depressions may be provided.

[0063] Fig. 46 shows a sectional view of a spray nozzle 200 according to another embodiment of the invention. The spray nozzle 200 is constructed very similarly to the spray nozzle 10 of Fig. 1 to 16 , so that only the differences to the spray nozzle 10 are explained.

[0064] In particular, the housing 12 of the spray nozzle 200 is structurally identical to the housing 12 of the spray nozzle 10. The spray nozzle 200 is designed as a flat jet nozzle. The housing 12 has a truncated cone-shaped piston seat 28. A channel-like recess 30 is provided in the piston seat 28, through which the liquid to be sprayed can flow when the piston 20 is in the spraying position, in which it rests against the piston seat 28. Liquid emerging from the outlet opening at the end of the channel-like recess 30 then strikes the impact surface 22 and is thereby formed into a flat jet.

[0065] In contrast to the spray nozzle 10, the piston 202 is located at its Fig. 46 The outer circumference located above the piston seat 28 does not abut an inner wall 204 of the housing 12. The inner wall 204 defines a cylindrical portion in which a portion of the piston 202 is received.

[0066] As a result, the liquid to be sprayed can flow both through a passage 206 in the piston 202 and radially outside the piston between the inner wall 204 of the housing 12 and the piston 202. Consequently, the spring 24 is also surrounded by the liquid to be sprayed.

[0067] Fig. 47 shows detail D from Fig. 46 It is clearly visible that the liquid to be sprayed is in the Fig. 46 and Fig. 47 shown spray position of the piston 202 both radially outside the piston 202 and through the passage 206 in the piston 202. This is indicated by arrows in Fig. 47As a result, the liquid to be sprayed flows past the piston 202 and through the through-channel 206 in the piston 202, and then enters the channel-like recess 30. The leakage flow flowing laterally around the piston 202 is therefore not lost, but merges with the liquid flowing through the through-channel 206 before entering the channel-like recess 30.

[0068] Up to the area of ​​the piston seat, the spraying position of the piston 202, which is in Fig. 46 and Fig. 47As shown, there is therefore no significant reduction in the pressure of the liquid to be sprayed. Within the housing 12 of the nozzle 200, there is only a single sealing point between the piston 202 and the housing 12, namely at the piston seat 28. No wall friction occurs between the piston 202 and the inner wall 204 of the housing 12, since the piston 202 does not bear against the inner wall 204. As a result, the spray nozzle 200 is extremely reliable, since no friction and thus no hysteresis occurs when the piston 202 moves from the spray position to the cleaning position.

[0069] The leakage flow, which flows between the piston 202 and the inner wall 204 of the housing 12, is reintegrated into the main flow, even before entering the channel-like recess 30. The so-called leakage flow thus also contributes to the function of the nozzle.

[0070] Fig. 48 shows the spray nozzle 200 of the Fig. 46in a sectional view, wherein the piston 202 is in the cleaning position and the piston 202 consequently does not rest on the piston seat 28 in the housing 12.

[0071] Fig. 49 shows detail D from Fig. 48 on an enlarged scale. In Fig. 49 The flow paths of the fluid flowing through the nozzle 200 are indicated by arrows. It can be seen that even in the cleaning position of the piston 202, the fluid flows radially outside the piston 202, between the piston 202 and the inner wall 204 of the housing. Furthermore, even in the cleaning position of the piston, the fluid flows through the passage 206 in the piston 202. Since the piston 202 is in the cleaning position, the fluid also flows past the piston seat 28 of the housing 12 and the channel-like recess 30 in the piston seat 28, so that any contaminants can be flushed out of the housing 12.

Claims

1. Spray nozzle for spraying liquids with a housing (12; 102) with an inlet opening (14) and an outlet opening (16) for liquid to be sprayed, wherein at least one flow path for the liquid to be sprayed is provided between the inlet opening (14) and the outlet opening (16), characterized in that the at least one flow path is formed at least in sections between a piston (20; 80) displaceable within the housing (12; 102) and a piston seat of the housing (12; 102), wherein the piston (20; 80) is displaceable between a spraying position and a cleaning position.

2. Spray nozzle according to claim 1, characterized in that the piston (20; 80) and / or the piston seat are geometrically adapted to one another and that the piston seat, which tapers at least in sections in the direction of flow, and the piston (20; 80) in the spray position bear against one another in a sealing manner at least in the region of a contact line.

3. Spray nozzle according to claim 1 or 2, characterized in that the piston (20; 80) and the piston seat are at least partially frustoconical in shape and wherein in the spraying position a frustoconical section (26; 126) of the piston (20; 80) bears against a frustoconical section (26; 126) of the piston seat (28; 128) and in the cleaning position the frustoconical section (26; 126) of the piston (20; 80) is lifted off the frustoconical section (26; 126) of the piston seat (28; 128).

4. Spray nozzle according to one of the preceding claims, characterized in that the piston (20; 80) and / or the piston seat (28; 128) has at least one channel-like recess (30; 130) which forms part of the flow path in the spray position.

5. Spray nozzle according to one of the preceding claims, characterized in that a cross-section of the channel-like recess (30; 130) is reduced at least in sections in the flow direction.

6. Spray nozzle according to claim 4 or 5, characterized in that at least one channel-like recess (30; 130) runs straight along a surface line of the frustoconical section (126) of the piston (20; 80) and / or the frustoconical section of the piston seat (28; 128), in particular offset or skewed to the central longitudinal axis of the housing (72).

7. Spray nozzle according to claim 4, 5 or 6, characterized in that at least one channel-like recess (130) runs helically along the truncated cone-shaped piston (20) and / or the truncated cone-shaped piston seat.

8. Spray nozzle according to one of the preceding claims, characterized in that the piston (20; 80) is pretensioned into the cleaning position by means of a spring (24), wherein in particular the spring (24) is arranged within the housing (12) and is surrounded by the liquid to be sprayed, at least during spraying operation.

9. Spray nozzle according to at least one of the preceding claims, characterized in thatupstream of the piston seat, the piston is spaced from an inner wall of the housing, so that liquid to be sprayed can flow between the inner wall of the housing and the sections of the piston located upstream of the piston seat, both in the spraying position and in the cleaning position.

10. Spray nozzle according to at least one of the preceding claims, characterized in that the piston has at least one through-channel which opens upstream of the piston seat into a space between an inner wall of the housing and the piston.

11. Spray nozzle according to one of the preceding claims, characterized in thatthe housing (12) has a baffle surface (22), wherein the flow path within the housing (12) ends at the outlet opening (16) and wherein the outlet opening (16) and the baffle surface (22) are arranged such that, in the spray position of the piston (20; 80), a liquid jet emerging from the outlet opening (16) strikes the baffle surface (22).

12. Spray nozzle according to claim 11, characterized in that the outlet opening (16) in the spray position of the piston (20; 80) is formed by means of the frustoconical section of the piston seat (28; 128) and by means of the frustoconical section of the piston (20; 80).

13. Spray nozzle according to claim 12, characterized in that the outlet opening (16) in the spraying position of the piston (20; 80) is formed in sections by means of a channel-like recess (30; 130) in the piston and / or the piston seat.

14. Spray nozzle according to at least one of the preceding claims, characterized in thata swirl chamber (92) is arranged upstream of the outlet opening in the housing, wherein in particular the piston seat and the piston are arranged upstream of the swirl chamber (92).

15. Method for operating a spray nozzle according to at least one of the preceding claims, characterized by Setting a first pressure of a liquid to be sprayed in a spraying operation and by setting a second pressure of the liquid to be sprayed in a cleaning operation, wherein the second pressure is lower than the first pressure.

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