Vertical backflow preventer with a valve tappet guide which is shielded on the outlet side

Abstract

The invention relates to a backflow preventer for a vertical installation in a waste water pipe gradient. The backflow preventer has a waste water inlet followed by a waste water outlet in the direction of the waste water passage path of the backflow preventer, and the waste water passage path points at least partly in the direction of gravity when the backflow preventer is in a vertical installation orientation. The backflow preventer has a closable valve unit between the waste water inlet and the waste water outlet, and the valve unit allows a flow of waste water in the direction of the waste water passage path by means of a sealing interaction between a movably guided valve tappet and a valve seat opening when the backflow preventer is in a vertical installation orientation and blocks a flow of waste water in the direction opposite the waste water passage path in a backflow situation. The guide of the valve tappet is provided on the outlet side of the valve seat opening in a region which is shielded from the valve seat opening by the valve tappet. The invention also relates to a corresponding waste water lifting system.

Description

[0001] Vertical backflow preventer with shielded valve tappet guide on the outlet side

[0002] The present invention relates to a wastewater backflow preventer having the features of independent claim 1 and an associated wastewater lifting system.

[0003] EP2177679A1, for example, discloses a backflow preventer which is also suitable for very contaminated household wastewater, such as wastewater containing faeces.

[0004] Overall, however, it is clear that many common backflow preventers have weaknesses when conveying particularly contaminated wastewater, for example, when conveying wastewater containing feces. In this case, dirt particles can adhere to the movable closing parts of the backflow preventer or the sealing seals, impairing the functionality of these parts and thus the backflow preventer. Therefore, complex design measures are being taken to improve or ensure the function of the backflow preventer in the event of backflow.

[0005] The present invention is based on the object of improving the operational reliability of a wastewater backflow preventer and, at the same time, making the backflow preventer as structurally simple as possible.

[0006] The present invention solves the stated problem with the features of independent claim 1.

[0007] The present invention proposes a backflow preventer for vertical installation in a sewer pipe gradient, wherein the backflow preventer has a wastewater inlet followed by a wastewater outlet in the direction of its wastewater passage path, and the wastewater passage path in a vertical installation orientation of the backflow preventer points at least partially in the direction of gravity, wherein the backflow preventer has a closable valve unit between the wastewater inlet and the wastewater outlet, and the valve unit in a vertical installation orientation of the backflow preventer allows a wastewater flow in the direction of the wastewater passage path by means of a sealing interaction of a movably guided valve stem with a valve seat opening and blocks it in the direction opposite to the wastewater passage path in a backflow situation,and wherein the guide of the valve tappet is arranged on the outlet side of the valve seat opening in an area shielded by the valve tappet from the valve seat opening.,

[0008] By arranging the valve tappet guide on the outlet side of the valve seat opening in a vertical backflow preventer area shielded by the valve tappet from the valve seat opening, the guide, which is crucial for the reliable function of the backflow preventer, can be protected from the falling wastewater jet. The valve tappet itself advantageously provides the shielded area through its projection shadow in the direction opposite the valve seat opening, thus reducing the risk of contaminants adhering to the moving parts of the guide. This helps reduce contamination-related malfunctions, which increases operational reliability.

[0009] An arrangement of the guide in the area shielded by the valve tappet also enables a compact design of the backflow preventer and an advantageous positioning of the guide in alignment with the valve seat opening, for example in the form of a linear guide.

[0010] At the same time, the vertical installation orientation of the backwater valve allows for high flow velocities within the backwater valve, aided by gravity, significantly reducing the unwanted adhesion of contaminants to parts of the backwater valve through rapid flushing. In addition, gravity in the vertical installation orientation helps to quickly transport wastewater and the contaminants it contains out of the backwater valve, further reducing the risk of contaminants adhering and contributing to increased functional reliability.

[0011] The aforementioned advantages mean that the backflow preventer according to the invention can also be used reliably with particularly problematic wastewater, such as wastewater containing faeces (“black water”).

[0012] In an optional embodiment, the valve tappet can have a cavity that is closed toward the valve seat opening and open in the direction opposite the valve seat opening, with the guide being at least partially positioned within the cavity. Such a valve tappet design with a cavity according to the invention shields the guide particularly reliably from the wastewater surge coming from the valve seat opening. This applies even more so if, in a further optional embodiment, the guide is positioned entirely within the cavity.

[0013] In addition, the cavity creates a diving bell effect in the event of backflow, protecting the cavity and the components within it from rising backwater levels. Furthermore, the cavity serves as a buoyancy body that can provide additional closing force toward the valve seat opening in the event of backflow. In another optional embodiment, the guide is positioned completely within the cavity when the valve stem is fully open, viewed perpendicular to the direction of the wastewater flow path.

[0014] This shields the guide particularly in a situation when the falling wastewater jet is at its most intense, namely when the valve stem is fully open.

[0015] In a further advantageous embodiment, the cavity can taper at least in sections towards the valve seat opening.

[0016] This reduces the risk of backflowing wastewater penetrating deeper into the cavity from below in the event of a sewage backflow. By tapering the cavity upwards toward the valve seat opening, the air in the diving bell-like cavity is compressed more quickly by the sewage backflow level to a pressure that withstands the backflow pressure and prevents the level in the cavity from rising further. This protects components located in the cavity, such as the valve stem guide, from contact with and penetration of contaminated backflow wastewater.

[0017] In a further optional embodiment of the invention, a wastewater guide surface is provided in the region of the valve seat opening, which guides wastewater flowing through the valve seat opening past the open valve tappet in a turbulence-reducing manner.

[0018] This reduces the turbulence in the wastewater caused by the valve effect at the valve seat opening, which has a calming effect on the falling wastewater, allowing it to pass through the backwater valve more quickly. This reduces the risk of an overly turbulent wastewater-air mixture forming, which could accumulate in the backwater valve and penetrate the valve stem guide.

[0019] In a preferred optional embodiment, the wastewater guide surface is at least partially hood-shaped. A hood shape, in particular, has produced particularly good results in reducing turbulence in the falling wastewater jet.

[0020] In another, particularly advantageous optional embodiment, a portion of the valve stem extends into a hood formed by the wastewater guide surface when fully open. This allows the falling wastewater to be reliably calmed and efficiently directed through the backflow preventer, even when the valve stem is fully open and the intensity of the downflow jet is particularly high.

[0021] In another possible embodiment, a water drainage base of the backflow preventer, located opposite the valve seat opening, has an incline toward the wastewater outlet. This allows the wastewater outlet to be positioned out of alignment with the valve seat opening, thus reducing the installation height of the backflow preventer while still reliably draining wastewater and contaminants toward the wastewater outlet.

[0022] In an advantageous, optional development of the invention, at least a large portion of the water drainage floor can be designed as a chute leading to the wastewater outlet. This further improves the reliable and rapid discharge of wastewater and prevents contaminants from adhering to the floor due to gravity in a lateral wastewater outlet. In further optional embodiments, the entire water drainage floor, or almost the entire water drainage floor, is designed as such a chute.

[0023] In an advantageous optional embodiment, the guide is supported on the water drainage floor.

[0024] This allows the valve unit area to be kept free of components supporting the guide, as the guide is supported from the bottom of the housing. This reduces the risk of dirt particles adhering to the valve unit area.

[0025] In an optional embodiment, the guide is supported on a sloped water drainage base. In this embodiment, the slope of the water drainage base advantageously allows the guide to be positioned closer to the valve seat opening, even though the guide is attached to the housing base. This allows the guide to be shorter, reducing the risk of contamination and the shielding effort for the guide.

[0026] Advantageously, in a further possible embodiment, the backflow preventer can have a sudden wastewater passage area widening at the valve seat opening.

[0027] A sudden widening of the wastewater passage area in the direction of the wastewater passage path creates a valve effect at the valve seat opening, which reduces the adhesion of contaminants in the valve area.

[0028] The valve effect is particularly evident in designs where the valve stem is closed by default and the wastewater is pressurized above the valve seat opening. In such a case, the wastewater is transferred to a pressureless gravity drainage system at the wastewater passage widening.

[0029] In further optional embodiments, the wastewater passage area for the flowing wastewater expands abruptly by at least 25%, in particular by at least 50%, and in particular by at least 75%. An optional expansion of at least 25% already reduces deposits particularly effectively, which can be further increased by expanding by at least 50%, and at least 75% ensures even better results.

[0030] In a further, particularly advantageous optional embodiment, at least part of the guide of the valve tappet is arranged in a cup which is closed in the direction opposite the valve seat opening and open in the direction towards the valve seat opening, wherein the cup opening is located in the shielded area.

[0031] The arrangement of at least part of the guide in such a cup further reduces the risk of contamination and thus improves the operational reliability of the backflow preventer. Furthermore, the edge of the cup opening forms a dam, which further protects the guide from contact with the backflow wastewater in the event of a sewage backflow situation.

[0032] With an optional design in which the cup opening is located in the valve stem cavity, at least when the valve stem is fully open, the risk of contamination from wastewater falling from the valve seat opening, as well as in the event of backflow, is further reduced. In the event of backflow, this is because the cavity counteracts the rising of backflow wastewater toward the cup opening through the diving bell effect.

[0033] In a further optional embodiment, the cup opening is located in the valve tappet cavity both in the fully open and closed positions. This further enhances the aforementioned protective effects.

[0034] In a further optional embodiment, the cup is arranged relative to the valve tappet such that movement of the valve tappet from the closed position toward the fully open position causes a reduction in the distance between the cup opening and the ceiling of the cavity.

[0035] This has the advantageous effect that an increasing wastewater flow through the valve seat opening increases the protection of the cup interior against penetrating wastewater.

[0036] In a particularly advantageous optional embodiment of the present invention, the valve tappet is automatically held in the closed position and opens automatically in the event of a wastewater passage event.

[0037] This creates a particularly large air cushion on the outlet side of the closed valve seat opening in the event of backflow, even with a gradually rising backflow level, thus protecting the guide and other functionally relevant parts from contact and contamination with backflow wastewater. The automatic opening ensures the passage of wastewater arriving at the sealing tappet on the inlet side toward the wastewater passage path.

[0038] In a further optional embodiment, a spring element is arranged in the shielded area, which pushes the valve tappet into the closed position and allows it to open automatically in the event of a wastewater passage event.

[0039] The automatic opening and closing is effected by a spring element, which is protected from the wastewater jet in the shielded area.

[0040] Advantageously, the aforementioned spring element is arranged in the aforementioned cup.

[0041] This further increases the protection of the spring element from both the wastewater jet and backflow wastewater.

[0042] In a further optional embodiment, the waste water inlet opening and / or the waste water outlet opening are arranged at an angle to the valve seat opening.

[0043] An angled arrangement of the wastewater inlet, the wastewater outlet, or both to the valve seat opening of the vertical backwater valve allows for compact changes in pipe connection direction. This allows the backwater valve, for example, to be installed directly below the ceiling without the need for additional vertical pipe runs above and below the vertical backwater valve.

[0044] The above description applies in particular to an orthogonal or nearly orthogonal arrangement.

[0045] In a further, optional embodiment, the backflow preventer has a ceiling mounting section on its top side in vertical installation orientation.

[0046] This facilitates and ensures installation at the highest geodetic level available on site, the ceiling.

[0047] This increases the effectiveness of the backflow preventer in the event of backflow and prevents incorrect installation.

[0048] A further, optional embodiment of the invention relates to a particularly reliable wastewater lifting system comprising a backflow preventer according to one of the previous embodiments.

[0049] Here, a wastewater lifting system is proposed, comprising a wastewater lifting plant with a wastewater conveying line, wherein the wastewater lifting plant is designed to pump wastewater through the wastewater conveying line in the wastewater conveying direction from a geodetically lower level to a geodetically higher drainage level, wherein the wastewater conveying line has a riser section in the wastewater conveying direction, a curved line section with a peak level of the wastewater conveying line, and a downpipe section in which wastewater moves in the direction of gravity, the wastewater lifting system further comprising a backflow preventer according to one of the embodiments described here above, wherein the downpipe section has the backflow preventer.

[0050] It has surprisingly been shown that an arrangement in which the downpipe section features a backflow preventer protects the lifting station from excessive backflow of the wastewater column after a lifting operation has stopped. At the same time, the backflow preventer is particularly vigorously flushed with wastewater during lifting, thus protecting it from adhering contaminants and ensuring reliable operation. In addition, the advantages of the backflow preventer according to the invention, already explained here, create a particularly reliable wastewater lifting system.

[0051] In optional embodiments of the aforementioned embodiments of the backflow preventer according to the invention, the main axis of extension of the backflow preventer extends along the vertical in the installation orientation and runs in the direction of gravity. Steep angular deviations of the main axis of extension in the installation orientation of up to 20° from the vertical, in particular up to 5° from the vertical, are also included in further embodiments of the invention.

[0052] In further optional embodiments of all the aforementioned embodiments of the invention, the wastewater conveying line of the wastewater lifting system according to the invention is unventilated from the lifting station to the backflow preventer, in particular at least up to the sealing level of the backflow preventer.

[0053] This improves the backlash dampening effect as well as the reaction speed of the system due to particularly quickly building pressure differences.

[0054] In further optional embodiments of all the aforementioned embodiments of the invention, said wastewater conveying line is not ventilated from the lifting station to the point of entry into a hierarchically superior wastewater downpipe, for example into the central wastewater downpipe of a building.

[0055] In further optional embodiments of all the aforementioned embodiments of the invention, the apex level of the wastewater conveying line lies geodetically above the local backflow level. In further optional, alternative embodiments of all the aforementioned embodiments of the invention, the apex level of the wastewater conveying line lies geodetically below the local backflow level.

[0056] In preferred optional embodiments of the aforementioned wastewater lifting system of the invention, the extension axis of the downpipe section according to the invention extends along the vertical and runs in the direction of gravity. Steep angular deviations of the extension axis of the downpipe section of up to 20° from the vertical, in particular up to 5° from the vertical, are also included in further embodiments of the invention.

[0057] All of the embodiments described above can be combined with each other as desired.

[0058] The following figures explain the advantages and functions of the invention in more detail with reference to the figures, which show possible embodiments of the invention that advantageously combine the previously mentioned embodiments. Some functionally equivalent features are provided with the same reference symbols for the sake of clarity.

[0059] It shows

[0060] Figure 1 shows a cross section through a backflow preventer according to the invention in its installation orientation with its valve tappet in the closed position, cut along the central main extension axis of the backflow preventer, which is vertical here,

[0061] Figure 2 shows the backflow preventer from Fig. 1 with the valve stem in the fully open position,

[0062] Figure 3 shows a perspective view obliquely from above of the isolated valve tappet, in the closed position, together with the isolated backflow preventer base,

[0063] Figure 4 shows a sectioned upper section of Fig. 3, cut along the main extension axis of the backflow preventer,

[0064] Figure 5 shows an embodiment of a wastewater lifting system according to the invention with a backflow preventer according to the invention.

[0065] Figure 1 shows an embodiment of a backflow preventer 1 according to the invention in a sectional view, cut centrally along the main extension axis A of the backflow preventer 1. The backflow preventer 1 is shown here in its vertical installation orientation. The main extension axis A of the backflow preventer 1, which is cylindrical in its basic shape, is vertical here, or coincident with the vertical V, and accordingly parallel to the direction of gravity S.

[0066] In its upper area, the backflow preventer 1 has a wastewater inlet 2, designed here as a nozzle. In its lower area, the backflow preventer 1 has a wastewater outlet 3, designed here as a nozzle. In the vertical installation orientation, the wastewater inlet 2 is at a geodetically higher level than the wastewater outlet 3. During operation, wastewater flows through the backflow preventer 1 in the direction of a wastewater passage path 4 from the wastewater inlet 2 to the wastewater outlet 3.

[0067] The backflow preventer 1 has a closable valve unit 5, which is arranged along the wastewater passage path 4 between the wastewater inlet 2 and the wastewater outlet 3.

[0068] The valve unit 5 has a movably guided valve tappet 6 and a valve seat opening 7. The valve tappet 6 and the valve seat opening 7 interact in a sealing manner. The valve tappet 6 can be moved back and forth along its movement axis B between a fully open position and a closed position, in which it seals the valve seat opening 7. Figure 2 shows the valve tappet 6 in the fully open position. In this position, the valve seat opening 7 is exposed by the valve tappet 6.

[0069] In this embodiment, the movement axis B of the valve tappet 6 coincides with the main extension axis A of the backflow preventer 1 and is orthogonal to the sealing plane D of the backflow preventer 1 spanned by the valve seat opening 7. In the installation orientation, the movement axis B is parallel or coincident with the vertical V and thus parallel to the direction of gravity S.

[0070] The backflow preventer 1 has a guide 8 for the movable valve tappet 6 on the outlet side, facing the valve seat opening 7. In the present embodiment, the guide 8 is a linear guide, here in the special variant of a movable telescopic guide. Other guide variants are also conceivable in further embodiments, for example, a tongue-and-groove linear guide between the valve tappet 6 and a stationary guide element.

[0071] The guide 8 guides the movable valve tappet 6 along its movement axis B between the closed and the fully open position. The guide 8 has a lower, fixed sleeve 9 and an upper, movable sleeve 10, which is firmly connected at one end 11 to an underside of the valve tappet 6, here to the cover 38 in the cavity 27, and which, at its opposite end section 12, partially encloses the fixed sleeve 9 along the movement axis B, wherein the mutually sliding contact surfaces 13, 14 of the fixed sleeve 9 and the movable sleeve 10 guide the movement of the valve tappet 6, such that the fixed sleeve 10 can slide back and forth along the movement axis B together with the valve tappet 6.

[0072] A spring element 15, in this embodiment in the form of a spiral spring, presses the valve tappet 6 into the closed position.

[0073] The spring element 15 automatically closes and holds the valve stem 6 in the closed position and, in the event of a wastewater passage event, when wastewater pressing against the valve stem 6 on the inlet side overcomes the spring force, releases the valve seat opening 7 by moving it towards the fully open position so that the wastewater can flow along the wastewater passage path 4 towards the wastewater outlet 3.

[0074] The opening force of the spring element in the closed position of the valve tappet is in possible embodiments in the range of 1 Newton to 10 Newton, in particular in the range of 1.5 Newton to 5 Newton, depending on the valve seat opening area.

[0075] In further possible embodiments, the valve tappet opens when the wastewater pressure on the inlet side at the valve seat opening is in the range of 0.1 bar to 1 bar, in particular in the range of 0.15 bar to 0.5 bar.

[0076] In the embodiment shown, the valve seat opening has a diameter of 54 mm. In further embodiments, the diameter of the valve seat opening is in the range of 30 mm to 100 mm, in particular in the range of 40 mm to 70 mm.

[0077] In this embodiment, both the waste water inlet opening 16 and the waste water outlet opening 17 are perpendicular or almost perpendicular to the valve seat opening 7, which extends horizontally here. Accordingly, the associated nozzles point in opposite horizontal directions.

[0078] In other embodiments not shown, the waste water inlet opening 16 and / or the waste water outlet opening 17 are parallel to the valve seat opening 7; accordingly, in these embodiments, the waste water inlet 2 and / or the waste water outlet 3 point in the direction along the main extension axis A.

[0079] In this embodiment, the wastewater passage path 4 runs perpendicular to the main extension axis A in the area of ​​the wastewater inlet 2, along the main extension axis A in the area of ​​the valve seat opening 7, i.e. in a vertical installation orientation in the direction of gravity S, and perpendicular to the main extension axis A in the area of ​​the wastewater outlet 3. As also shown in Figures 1 and 2, the backflow preventer 1 has a wastewater guide hood 18 in the area of ​​the valve seat opening 7. In this embodiment, the wastewater guide hood 18 surrounds the valve seat opening 7 on its outlet side. The dome-shaped inner surface of the wastewater guide hood 18 provides a wastewater guide surface 19, which calms wastewater flowing through the valve seat opening 7 and guides it past the open valve tappet 6 in the direction of gravity S with reduced turbulence.

[0080] In this embodiment, the wastewater guide surface 19 is dome-shaped and curved in the direction of the wastewater passage path 4. Its curvature approximately corresponds to the crest 20 of the valve tappet head 21 opposite the valve seat opening 7, which will be explained in more detail later. In this embodiment, the wastewater guide hood 18 and the crest 20, as well as the valve seat opening 7, have a common rotationally symmetrical axis, coinciding here with the main extension axis A.

[0081] Fig. 2 further shows that in the fully open position of the valve tappet 6, an upper part of the valve tappet, here the tip 20, projects into the wastewater guide hood 18 along the main extension axis A, and thus along the movement axis B.

[0082] As can also be clearly seen in Fig. 2, in this embodiment, a sudden wastewater passage area widening 22, here a sudden horizontal widening of approximately 100% in the clear width, is realized at the valve seat opening 7 below the valve seat opening 7 and thus below the sealing plane D. However, smaller percentage widenings of at least 25% are also conceivable in other embodiments. Here, the clear width in the horizontal direction jumps directly below the sealing plane D onto the curved wastewater guide surface 19 of the wastewater guide hood 18.

[0083] Figures 1 and 2 further show a ceiling mounting section 23, here with a mounting flange (not shown) with through holes, which the backflow preventer 1 has on its upper side in a vertical installation orientation and which is designed to be able to mount the backflow preventer 1 directly on a room ceiling 24.

[0084] Figure 3 shows a perspective, isolated view obliquely from above of the valve tappet 6 and the underlying water drainage base 25, designed here as a concave channel chute. At least sections of the concave channel chute form an extension axis R, which is inclined towards the wastewater outlet 3, as can be clearly seen in Figs. 1 and 2. Cross sections through the channel 25 parallel to the main extension axis A are U-shaped along the axis R. The extension axis R here forms an acute angle of approximately 50° with the main extension axis A. In other embodiments, the acute angle can be in the range of 85° to 20°. The valve tappet 6 is supported via the guide 8 on a pedestal 26 protruding from the water drainage base 25 along the main extension axis A. In this embodiment, the guide 8, and thus also the valve tappet 6, are supported on the water drainage base 25 via the pedestal 26.

[0085] Fig. 4 shows a sectional view, cut along the main extension axis A, of the upper region of Fig. 3 and thus also cut along the movement axis B of the valve tappet 6.

[0086] As can be clearly seen in the combination of Fig. 3 and Fig. 4, the valve tappet 6 forms a diving bell through its inner cavity 27. In this embodiment, the valve tappet 6 has a generally approximately rotationally symmetrical hollow body extending along the movement axis B, which is only open at its lower end 28 and is otherwise closed all the way to its opposite upper end 29. The main section of the valve tappet 6 has an elongated jacket section 30 which tapers along the movement axis B, at least in its upper section, towards the valve tappet head 21, wherein the valve tappet head 21 widens upwards like a mushroom head and merges into the dome 20, which in the closed position partially retracts into the valve seat opening 7 and seals against it, as can be clearly seen in Fig. 1.

[0087] The jacket section 30 has a section region 32 in the region of the lower opening 31 of the valve tappet 6, delimited at its upper end by a step 49 which tapers the jacket section 30 in diameter, so that the lower section region 32 forms a slightly wider open apron in cross section.

[0088] The inner cavity 27 of the valve tappet 6 tapers, roughly following the outer tappet contour, in this embodiment at least above the skirt 32 up to the head 21, as can be clearly seen in Fig. 4.

[0089] Fig. 4 also clearly shows the telescopic linear guide 8, which in this embodiment is arranged in a cup 33 that is fixedly mounted on the upper side of the pedestal 26 and is open only upwards, i.e., in the direction of the valve seat opening 7, and is otherwise closed. The upper opening edge 34 of the cup 33 forms a dam against wastewater rising from below in the event of backflow, i.e., against the direction of the wastewater passage path 4. However, the cup 34 also offers additional splash protection against the wastewater jet coming from the valve seat opening 7.

[0090] Also clearly visible in Fig. 4 is the spring element 15, which is also arranged in the cup 33, more precisely, between the multi-part guide 8 and the cup inner wall 35. The spring element 15 is securely supported with one end on a foot of the lower sleeve 9, which sits on the bottom 36 of the cup 33, and is thus supported via the pedestal 26 on the water drainage bottom 25.

[0091] The other end of the spring element 15 is supported on the inner side of the valve tappet head 21 and thus on the ceiling 38 of the cavity 27.

[0092] For example, looking at Figures 1 and 2, the area 37 shielded by the valve tappet 6 toward the valve seat opening 7 is provided by the projection shadow of the valve tappet 6 in the direction opposite to the valve seat opening 7.

[0093] In addition, in this embodiment, the guide 8 is partially positioned in the cavity 27 in the closed position of the valve stem 6 and completely positioned in the cavity 27 in the open position when viewed transversely to the wastewater passage path 4 at this point, and thus parallel to the valve seat opening 7, as can be clearly seen in Fig. 2.

[0094] In the fully open position of the valve tappet 6, the edge 34 of the cup opening 48 comes into contact with the ceiling 38 of the cavity 38 of the valve tappet 6, as can also be clearly seen in Fig. 2, or at least comes close to the ceiling 38. In the closed position of the valve tappet 6, the cup opening 48 in this embodiment of Fig. 1 lies above half the vertical extension of the cavity 27.

[0095] Figure 5 shows an embodiment of a wastewater lifting system 39 according to the invention with a backflow preventer 1 according to the invention.

[0096] The wastewater lifting system 39 comprises a wastewater lifting station 40, a wastewater conveying line 41 and the backflow preventer 1.

[0097] The wastewater lifting plant 40 is designed to pump wastewater through the wastewater conveying line 41 or through the wastewater conveying pipeline in the wastewater conveying direction 42 from a geodetically lower level to a geodetically higher drainage level.

[0098] In the present case, the lifting station 40 is designed to pump domestic wastewater, including wastewater containing faeces.

[0099] The lifting station 40 is connected at its pressure outlet to the beginning of the wastewater conveying line 41. The beginning of the wastewater conveying line 41 is formed by a vertically oriented riser section 43, which at its end merges into a curved line section 44, which has the apex level N of the wastewater conveying line 41. At the end of the curved line section 44, viewed in the wastewater conveying direction 42, the curved line section merges into a vertically oriented downpipe section 45, which here has the backflow preventer 1. In the present embodiment, the downpipe section 45 of the wastewater conveying line 41 is formed entirely within the backflow preventer 1.

[0100] In the vertical downpipe section 45, i.e. here in the backflow preventer 2, the wastewater coming from the lifting station 40 during lifting operation moves in the direction of gravity S. Following the wastewater outlet 3 of the backflow preventer is a straight gradient pipe 46 (with a gradient of approximately 2% here), which drains by gravity to a hierarchically superior sewer (not shown), more precisely to the central wastewater downpipe of the building (not shown).

[0101] The wastewater passage path 4 of the backflow preventer 1 forms part of the wastewater movement path of the wastewater conveying line 41.

[0102] In the present embodiment, the lower level of the lifting station 40 is just above the floor 47 of the installation space and the higher level is at the peak level N of the wastewater conveying line 41.

[0103] In the present embodiment, the riser section 43 is designed as a straight, vertically extending pipe. In embodiments not shown, the riser section 43 extends, for example, in a stair-step fashion, with one or more steps leading upward toward the curved section.

[0104] In further possible embodiments not shown, the downpipe section 45 does not immediately follow the curved pipe section 44, but there are further gradient sections of the wastewater conveying pipe 41 between the curved pipe section 44 and the downpipe section 45.

[0105] In the following, functions of the backflow preventer 1 according to the invention are briefly explained using the described embodiment.

[0106] In the present backwater valve 1, which in the embodiment shown has a spring element 15, the valve stem 7 is in a closed position by default. If the pressure of the wastewater on the valve stem 6 on the inlet side exceeds the closing force of the spring element 15, the valve stem 6 moves from its closed position along its vertical movement axis B toward the fully open position.

[0107] In this case, the head 21 of the valve tappet 6 releases the valve seat opening 7, so that the wastewater flows along the wastewater passage path 4 through the valve seat opening 7. In this case, at least at the beginning of the opening movement of the valve tappet 6, when the distance between the valve seat opening 7 and the tip 20 of the tappet head 21 is still comparatively small, the wastewater is pressed radially outwards against the wastewater guide surface and is thereby calmed by it and, somewhat like the fountain of a mushroom fountain, is guided following the force of gravity S to the water discharge base 25, which transports the wastewater via its chute channel to the wastewater outlet 3.

[0108] The telescopic linear guide 8 is pushed together during an opening movement of the valve tappet 6 and is at all times well protected from contact with the wastewater jet or the falling wastewater fountain by the valve tappet 6, here in particular by the apron 32 in the shielded area 37.

[0109] The cup 33 additionally protects against the penetration of lateral splash water, and the distance between the cup opening edge 34 and the cavity ceiling 38, which decreases during the opening movement, further contributes to the protection of the guide 8. The same also applies to the spring element 15 arranged in the cup 33.

[0110] If the inlet-side wastewater pressure on the valve tappet 6 is lower than the spring force, the valve tappet 6 automatically returns to its closed position.

[0111] In the event of wastewater backing up, an air cushion forms below the closed sealing plane D, so that in this embodiment the water level of the backing up wastewater rises on the outside of the closed valve tappet 6 to a maximum of just above the step 49. However, in the cavity 27 of the valve tappet 6, the water level remains lower than on the outside, and thus continues to be noticeably below the cup opening edge 34, because the cavity 27 tapers towards the top and thus the smaller air volume in the cavity 27 adjusts to the same pressure as that of the backing up wastewater more quickly than the outer air cushion. In addition, the downwardly open cavity 27 forms a buoyancy body in the event of backwater, which provides additional closing force in the direction of the valve seat 7.

[0112] In the event of backflow, the cup opening edge 34 thus forms a protective dam which prevents the guide 8 and also the spring element 15 from coming into contact with the backflow wastewater when the level of the backflow wastewater presses into the cavity 27.

[0113] In embodiments (not shown) without spring element 15, the valve tappet 6 is in the fully open position as standard, wherein the guide 8 lies in the protected shielded area 37 and can also optionally be protected by a surrounding cavity 27 of the valve tappet 6 and an optional cup 33.

[0114] In the event of backflow in such a spring-element-free embodiment, the cavity 27 of the valve tappet 6, which acts as a buoyancy body, will float into the closed position and close the backflow preventer 1. In the event of a rapidly rising backflow level, the valve tappet 6 is pressed into the valve seat 7 by the air pressure preceding the backflow level or by the air flow in the pipe flowing against the direction of the wastewater passage path 4. Here, too, an air cushion then forms below the sealing plane D, but usually later and thus smaller than with a automatically closing valve tappet. In this embodiment, however, the guide 8 remains unaffected by the backflow level due to the simultaneous diving bell effect of the cavity 27, especially in interaction with the cup 33.

[0115] In the wastewater lifting system 39 shown in Fig. 5, a backflow preventer 1 according to the invention reduces the backflow of the wastewater column onto the lifting station 40 when the lifting operation stops, because a backflow-like backflow or falling of the wastewater column in the riser section 43 against the wastewater conveying direction 42 is prevented by the backflow preventer 1. At the same time, the vertical backflow preventer 1 is particularly advantageously flushed by the pressure of the lifting station 40. In the embodiment shown here with the automatically closing valve tappet 6, a transition of the pressurized wastewater above it into a pressureless and falling gravity drainage takes place at the wastewater passage area widening 22 when the valve tappet 6 is opened. This keeps the backflow preventer 1 clean due to the particularly pronounced valve effect.

[0116] In this design, the backflow preventer 1 is mounted to the ceiling 24 with its ceiling mounting section 23 and thus cleverly utilizes the maximum available geodetic height at the installation site.

Claims

Claims 1. Backflow preventer (1) for vertical installation in a sewer pipe gradient, wherein the backflow preventer (1) has a wastewater inlet (2) followed by a wastewater outlet (3) in the direction of its wastewater passage path (4), and the wastewater passage path (4) points at least partially in the direction of gravity (S) in a vertical installation orientation of the backflow preventer (1), wherein the backflow preventer (1) has a closable valve unit (5) between the wastewater inlet (2) and the wastewater outlet (3), and the valve unit (5), in a vertical installation orientation of the backflow preventer (1), allows a wastewater flow in the direction of the wastewater passage path (4) by means of a sealing interaction of a movably guided valve tappet (6) with a valve seat opening (7) and blocks the flow in the direction opposite to the wastewater passage path (4) in a backflow situation, characterized in thatthat the guide (8) of the valve tappet (6) is arranged on the outlet side of the valve seat opening (7) in an area (37) shielded by the valve tappet (6) from the valve seat opening (7).

2. Backflow preventer (1) according to the preceding claim, wherein the valve tappet (6) has a cavity (27) closed towards the valve seat opening (7) and open in the direction opposite the valve seat opening (7), wherein the guide (8) is at least partially positioned in the cavity (27).

3. Backflow preventer (1) according to claim 2, wherein the guide (8) is positioned completely in the cavity (27) in the fully open position of the valve tappet (6), viewed transversely to the direction of the wastewater passage path (4).

4. Backflow preventer (1) according to claim 2 or 3, wherein the cavity (27) tapers at least in sections towards the valve seat opening (7).

5. Backflow preventer (1) according to one of the preceding claims, wherein in the region of the valve seat opening (7) a wastewater guide surface (19) is provided, which guides wastewater flowing through the valve seat opening (7) past the open valve tappet (6) in a turbulence-reducing manner, in particular the wastewater guide surface (19) is at least partially hood-shaped, in particular a part of the valve tappet (6) in the fully open position projects into a hood (18) formed by the wastewater guide surface (19).

6. Backflow preventer (1) according to one of the preceding claims, wherein a water drainage base (25) of the backflow preventer arranged opposite the valve seat opening (7) has an inclination towards the waste water outlet (3), in particular at least a large part of the water drainage base (25) is designed as a chute towards the waste water outlet (3).

7. Backflow preventer (1) according to one of the preceding claims, wherein the guide (8) is supported on the water discharge base (25) of the backflow preventer (1).

8. Backflow preventer (1) according to one of the preceding claims, wherein the backflow preventer (1) has a sudden wastewater passage area widening (22) at the valve seat opening (7), in particular a widening of at least 25%, preferably of at least 50%, preferably of at least 75%.

9. Backflow preventer (1) according to one of the preceding claims, wherein at least part of the guide (8) of the valve tappet (6) is arranged in a cup (33) which is closed in the direction opposite the valve seat opening (7) and is open in the direction towards the valve seat opening (7), wherein the cup opening (48) lies in the shielded area (37), in particular the cup opening (48) lies in the cavity (27) of the valve tappet (6) at least in the fully open position of the valve tappet (6).

10. Backflow preventer (1) according to claim 9, wherein the cup (33) is arranged relative to the valve tappet (6) such that a movement of the valve tappet (6) from the closed position towards the fully open position causes a reduction in the distance between the cup opening (48) and the ceiling (38) of the cavity (27).

11. Backflow preventer according to one of the preceding claims, wherein the valve stem (6) is automatically held in the closed position and opens automatically in the event of a wastewater passage event.

12. Backflow preventer (1) according to one of the preceding claims, wherein a spring element (15) is arranged in the shielded area (37), which spring element pushes the valve tappet (6) into the closed position and allows it to open automatically in the event of a wastewater passage event.

13. Backflow preventer (1) according to claim 12 and dependent on claim 9, wherein the spring element (15) is arranged in the cup (33).

14. Backflow preventer (1) according to one of the preceding claims, wherein the waste water inlet opening (16) and / or the waste water outlet opening (17) are arranged at an angle to the valve seat opening (7), in particular are arranged orthogonally or almost orthogonally to the valve seat opening (7), and / or the backflow preventer (1) has a ceiling mounting section (23) on its upper side in a vertical installation orientation.

15. Wastewater lifting system (39), comprising a wastewater lifting plant (40) with a wastewater conveying line (41), wherein the wastewater lifting plant (40) is designed to pump wastewater through the wastewater conveying line (41) in the wastewater conveying direction (42) from a geodetically lower level to a geodetically higher drainage level (N), wherein the wastewater conveying line (41) has a riser section (43) in the wastewater conveying direction (42), a curved section (44) with a peak level (N) of the wastewater conveying line (41), and a downpipe section (45) in which wastewater moves in the direction of gravity (S), the wastewater lifting system (39) further comprising a backwater valve (1) according to one of the preceding claims, wherein the downpipe section (45) has the backwater valve (1).

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