Waste water lifting system with a backflow preventer in a downpipe

Abstract

The invention relates to a waste water lifting system, having a waste water lifting assembly which comprises a waste water conveying line, wherein the waste water lifting assembly is designed to pump waste water through the waste water conveying line in the waste water conveying direction from a geodetically lower level to a geodetically higher drainage level. The waste water conveying line has, in the waste water conveying direction, a riser portion, a curved line portion which has the apex level of the waste water conveying line, and a downpipe portion in which waste water moves in the direction of gravity. The waste water lifting system also has a backflow preventer which allows waste water to pass through in the waste water conveying direction and closes in the event of a waste water backflow event. The waste water lifting system is characterized in that the downpipe portion has the backflow preventer. The invention additionally relates to an associated method for installing or improving a waste water lifting system and to an associated use of a waste water backflow preventer for improving the system reliability.

Description

[0001] Wastewater lifting system with backflow preventer in downpipe

[0002] The present invention relates to a sewage lifting system having the features of the independent device claim, as well as an associated method for installing or improving a sewage lifting system and an associated use of a sewage backflow preventer for improving system reliability.

[0003] It is known that sewage lifting stations are used to pump wastewater accumulating in low-lying rooms, for example in basements, through a wastewater conveying pipe to a geodetically higher drainage level, so that the pumped wastewater can then drain from this higher drainage level to the sewer system by gravity.

[0004] The path of the wastewater conveying line comprises a riser section starting from the wastewater lifting plant in the wastewater conveying direction to an upper curved pipe section, whereby after the curved pipe section, which has the apex level of the wastewater conveying line, a downpipe section follows in which wastewater moves in the direction of gravity and is subsequently drained to a hierarchically superior channel.

[0005] It has been shown that such wastewater lifting systems still have room for improvement in terms of their reliability. The lifting systems are comparatively maintenance-intensive, especially those that pump wastewater containing faeces (so-called "black water"). Maintenance of the lifting system that is not performed at the correct intervals or is performed incorrectly can easily jeopardize its reliable operation.

[0006] The present invention is based on the object of improving the operational reliability of a wastewater lifting system.

[0007] The present invention solves the stated problem with the features of claim 1.

[0008] 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, and the wastewater lifting system further comprising a backflow valve which allows wastewater to pass through in the wastewater conveying direction and closes in the event of a wastewater backflow event, wherein the downpipe section has the backflow valve.

[0009] Surprisingly, it has been shown that the installation of a sewage backflow preventer in the downpipe section of the sewage conveying line has an unexpectedly multiple positive effect on the reliability of the sewage lifting system as a whole.

[0010] By closing the backflow valve in the event of a backflow situation—that is, when wastewater tries to flow through the backflow valve against the direction of flow—the backflow valve prevents the column of wastewater still in the pipeline from backing up against the lifting station too quickly or too forcefully. This protects the lifting station's components, including any backflow preventer that may be installed in the lifting station.

[0011] The special positioning of the wastewater backflow preventer in the downpipe or in the downpipe branch of the aforementioned wastewater conveying line reduces the risk of contamination that could impair the function of the relevant backflow preventer components, as these backflow preventer components are not located in a wastewater sump and are not surrounded by wastewater during the idle phases of the wastewater lifting station. Furthermore, the velocity of the flowing wastewater prevents contamination from adhering to the functionally relevant components of the backflow preventer. Furthermore, the arrangement in the downpipe section allows, for example, the design or location of functionally relevant components of the backflow preventer in areas of the backflow preventer protected from the wastewater fall, which reduces the risk of contamination and further increases the reliability of the backflow preventer.

[0012] In addition to the aforementioned advantages, the backflow preventer can also reliably protect the wastewater lifting system according to the invention from wastewater backflow from a hierarchically superior sewer system.

[0013] All of the aforementioned advantages result in a particularly reliable wastewater lifting system, in which, surprisingly, the backflow preventer improves the reliability of the lifting station, and the lifting station improves the reliability of the backflow preventer, so that the wastewater lifting system according to the invention can reliably pump even particularly problematic wastewater, such as sewage containing faeces ("black water"), to a higher drainage level. In an advantageous possible embodiment, the backflow preventer is designed to be automatically closed in a normal position and to open automatically in the event of a wastewater pumping event.

[0014] The normally closed position of the backflow preventer significantly reduces or dampens the backflow of the wastewater column onto the lifting station when it stops pumping by eliminating the reaction time until the backflow preventer closes, thus increasing system reliability.

[0015] At the same time, in the event of a wastewater backflow from the sewer system, particularly in the case of a slowly rising wastewater backflow, an air cushion forms on the outlet side of the backflow preventer sealing level, so that functionally relevant parts of the backflow preventer, in particular the movable closing mechanism, do not come into contact with the contaminated backflow wastewater - which further increases the usability of the system.

[0016] In a further optional and particularly advantageous embodiment, a transition from pressure conveyance to pressureless gravity drainage is realized in the backflow preventer by means of a wastewater passage area widening in the wastewater conveying direction.

[0017] Widening the wastewater passage area, and in particular optionally a sudden widening, allows for the creation of a transition from pressurized water or the pressure line to a pressureless gravity drainage system in wastewater lift operation. This enables and simplifies the protected positioning of functionally relevant backflow prevention components in protected areas of the falling wastewater-air mixture.

[0018] In a further optional embodiment, the wastewater passage area is widened at the sealing level of the backflow preventer.

[0019] An optional widening of the wastewater passage area at the sealing surface of the backflow preventer cleverly utilizes the resulting jet effect, i.e., the resulting acceleration of the wastewater at this point, to keep the sealing surface clean and prevent wastewater contaminants from adhering to the sealing area of ​​the backflow preventer. All of this improves the reliability of the wastewater lifting system.

[0020] In further optional embodiments, the wastewater passage area for the pumped wastewater expands, optionally abruptly, by at least 25%, in particular by at least 50%, in particular by at least 75%. An optional expansion of at least 25% has already been shown to reduce deposits particularly effectively, which can be further increased by expanding by at least 50%, and at least 75% ensures even better results. An optional abrupt expansion, for example, in a stepwise manner, further improves the aforementioned effect.

[0021] In a further optional embodiment of the wastewater lifting system, a wastewater inlet nozzle and / or a wastewater outlet nozzle of the backflow preventer point transversely to the direction of gravity.

[0022] The transverse alignment of one or both nozzles to the direction of gravity allows for space-saving and easy installation of the backflow preventer in the downpipe section and minimizes incorrect installation when the direction of the wastewater conveying line changes.

[0023] In a further optional embodiment, the downpipe section is formed by the backflow preventer.

[0024] The section in which the wastewater moves in the direction of gravity is thus completely realized in the backflow preventer, which further reduces the risks of faulty design or installation on site and thus increases the reliability of the wastewater lifting system.

[0025] According to a further optional embodiment, the backflow preventer is attached to the local ceiling, in particular by means of a ceiling mounting attachment on its upper side.

[0026] This ensures that the backflow preventer is installed at the geodetically highest point of the installation space, thus increasing system reliability in the event of backflow events.

[0027] An optional ceiling mounting bracket located on top of the backflow preventer also ensures that the available room height is used to the best possible extent.

[0028] In a further optional embodiment of the invention, the backflow preventer realizes the beginning of the downpipe section.

[0029] This allows the backflow preventer to be installed close to the apex level and thus ensures good flushing by the pressurized wastewater, which reduces the adhesion of dirt particles and increases system reliability.

[0030] In another optional design, the backflow preventer is positioned at the end of the downpipe section. This allows for thorough flushing of the backflow preventer while optimizing the kinetic energy of the wastewater, reducing the adhesion of debris and increasing system reliability.

[0031] In a further optional, particularly advantageous embodiment, the backflow preventer has a movable sealing element which opens in the wastewater conveying direction and closes against the wastewater conveying direction, in particular the movable sealing element opens and closes automatically.

[0032] This allows the sealing element—which can be implemented, for example, as a movable sealing tappet or a pivoting drop flap—to be cleaned by the impact of falling water during the opening process. At the same time, the sealing element is designed to be self-repairing, as it is pulled into the closed position when negative pressure is applied. This increases the reliability of the system.

[0033] An optional automatic opening and closing, for example through the use of a spring element on a sealing tappet or on a swing flap or through the use of a closing weight on a rocking swing drop flap, further increases the system reliability.

[0034] The object mentioned at the outset is also achieved by a method for installing or improving a wastewater lifting system according to the independent method claim.

[0035] Said method comprises that a downpipe section of the wastewater conveying line of a wastewater lifting system is designed or provided with a backflow valve which allows wastewater to pass through in the wastewater conveying direction and closes in the event of a wastewater backflow event.

[0036] According to the method according to the invention, a new wastewater lifting system with a backflow preventer in the downpipe section can be newly installed or an existing wastewater lifting system can be retrofitted with a backflow preventer in the downpipe section.

[0037] The resulting improvements have already been explained in detail in the independent device claim. In summary, the method according to the invention results in a particularly reliable wastewater lifting system in which, surprisingly, the backflow preventer improves the reliability of the lifting system, and the lifting system improves the reliability of the backflow preventer, so that such an improved wastewater lifting system can reliably pump even particularly problematic wastewater, such as wastewater containing faeces, to a higher drainage level.

[0038] In an advantageous optional development of the method according to the invention, the backflow preventer is automatically closed in a normal position and opens automatically in the event of a wastewater pumping event.

[0039] As already explained above, a backflow valve closed in the standard or normal position significantly reduces backflow to the lifting station. At the same time, even in the case of gradual backflow, an air cushion reliably forms on the outlet side of the sealing plane, preventing functionally relevant parts from coming into contact with the backflow wastewater. All this improves system reliability.

[0040] In a further optional variant of the method according to the invention, the backflow preventer is designed and / or installed in such a way that it forms the beginning and / or the end of the downpipe section.

[0041] A possible realization of the beginning of the downpipe section allows for the installation of the backflow preventer close to the apex level and thus a good flushing by the pressurized wastewater, which reduces the adhesion of dirt particles and increases system reliability.

[0042] An alternative possible realization of the end of the downpipe section enables good flushing of the backflow preventer with the optimized utilization of the kinetic falling energy of the wastewater, which reduces adhesion of dirt particles and increases system reliability.

[0043] An alternative possible implementation of the beginning and end of the downpipe section through the backflow preventer makes it possible to take advantage of the previously mentioned benefits in the installation situation on site.

[0044] In an additional possible embodiment, the backflow preventer has a wastewater passage area widening in the wastewater conveying direction, in particular at its sealing plane, wherein the wastewater passage area widening realizes a transition from pressure conveying to pressureless gravity drainage in wastewater lifting operation.

[0045] Widening the wastewater passage area, especially an optional sudden widening, allows for the creation of a transition from pressurized water to pressureless gravity drainage during wastewater lifting. This enables or facilitates the protected positioning of functionally relevant backflow prevention components in protected areas within the falling wastewater-air mixture. In a further optional variant, the wastewater passage area widening is implemented at the sealing level of the backflow prevention device.

[0046] An optional widening of the wastewater passage area at the sealing surface of the backflow preventer cleverly utilizes the resulting jet effect, i.e., the resulting acceleration of the wastewater at this point, to keep the sealing surface clean and prevent wastewater contaminants from adhering to the sealing area of ​​the backflow preventer. All of this improves the reliability of the wastewater lifting system.

[0047] In a further optional embodiment of the method, the backflow preventer is mounted to the local ceiling, in particular by means of a ceiling mounting attachment on its upper side to the local ceiling.

[0048] This ensures that the backflow preventer is installed at the geodetically highest point of the installation space, thus increasing system reliability in the event of backflow events.

[0049] An optional installation using a ceiling mounting bracket located on top of the backflow preventer also ensures that the available room height is used in the best possible way.

[0050] The object formulated at the outset is further achieved by an inventive use of a wastewater backflow preventer for improving the system reliability of a wastewater lifting system.

[0051] This involves using a wastewater backflow preventer in the downpipe section of the wastewater conveying line of a wastewater lifting system to improve system reliability.

[0052] Further optional embodiments relate to the aforementioned use of a sewage backflow preventer to improve system reliability, wherein the sewage backflow preventer has one or more of the sewage backflow preventer features disclosed in the embodiments previously described herein relating to the sewage lifting system and the method for installing or improving a sewage lifting system.

[0053] 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.

[0054] This improves the backflow-damping effect and the system's response speed by allowing pressure differences to build up particularly quickly. In further optional versions of all the aforementioned embodiments of the invention, the wastewater conveying line is not vented from the lifting station to the point where it joins a higher-level wastewater downpipe, for example, 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 is 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 is geodetically below the local backflow level.

[0056] In preferred optional embodiments of all the aforementioned embodiments 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, provided they do not obviously exclude each other.

[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 first embodiment of a wastewater lifting system according to the invention,

[0061] Figure 2 is an enlarged sectional view in the area of ​​the backflow preventer from Fig. 1, cut parallel to the paper plane of Fig. 1,

[0062] Figure Its sectional view as in Fig. 2, with the cutting plane rotated perpendicular to Fig.

[0063] 2, so that you can see the sealing element in the closed normal position,

[0064] Figure 4 shows the sectional view from Fig. 3, with the sealing element in the fully open position,

[0065] Figure 5 shows a second embodiment of a wastewater lifting system according to the invention with a differently designed backflow preventer, Figure 6 shows an enlarged sectional view in the area of ​​the backflow preventer from Fig. 5, cut parallel to the plane of the paper of Fig. 5, with the sealing element in the closed normal position,

[0066] Figure 7 shows the sectional view from Fig. 6 with the sealing element in the fully open position.

[0067] Figure 1 shows a first embodiment of a wastewater lifting system 1 according to the invention. The wastewater lifting system 1 comprises a wastewater lifting plant 2, a wastewater conveying line 3 and a backflow preventer 4.

[0068] The wastewater lifting plant 2 is designed to pump wastewater through the wastewater conveying line 3 or through the wastewater conveying pipeline in the wastewater conveying direction F from a geodetically lower level to a geodetically higher drainage level.

[0069] In the present case, lifting station 2 is designed to pump domestic wastewater, including wastewater containing faeces.

[0070] The lifting station 2 is connected at its pressure outlet 5 to the beginning of the wastewater conveying line 3. The beginning of the wastewater conveying line 3 is formed by a vertically aligned riser section 6, which at its end merges into a curved line section 7, which has the peak level N of the wastewater conveying line 3.

[0071] In the present embodiment, the curved pipe section 7 has a horizontally running central section 8, which here has the geodetically highest point of the wastewater conveying pipe 3 and thus the apex level N, with curved sections 9, 10 curved by 90° at the respective ends. In an alternative embodiment not shown, the curved pipe section can also be designed without a noticeably pronounced central section, for example like an inverted "II".

[0072] At the end of the curved pipe section 10 viewed in the wastewater conveyance direction F, the curved pipe section merges into a vertically oriented downpipe section 11, which is sensibly shorter than the riser section 6.

[0073] In further possible embodiments not shown, the downpipe section 11 does not immediately follow the curved pipe section 10, but there are further gradient sections of the wastewater conveying pipe 3 between the curved pipe section 7 and the downpipe section 11.

[0074] In the vertical downpipe section 11, the wastewater coming from the lifting station 2 during lifting operation moves in the direction of gravity S. The end of the downpipe section 11 merges here through a pipe intermediate piece 12 located at almost 45° to the downpipe section 11 (formed by two 45° plug-in bends) into a straight gradient pipe 13 (with a 2% gradient here), which drains by gravity towards a hierarchically higher sewer (not shown), more precisely towards the central wastewater downpipe of the building (not shown).

[0075] In the present embodiment, the lower level of the lifting station 2 is just above the floor 14 of the installation space and the higher level is at the peak level N of the wastewater conveying line 3.

[0076] In the present embodiment, the riser section 6 is designed as a straight, vertically extending pipe. In embodiments not shown, the riser section runs, for example, in a stair-step fashion, with one or more steps leading upward toward the curved section 7.

[0077] In the present embodiment, the backflow preventer 4 is arranged at the end of the downpipe section 11. The backflow preventer 4 is configured to allow wastewater to pass through in the wastewater conveying direction F and to close in the event of a wastewater backflow event in which wastewater attempts to move through the backflow preventer 4 against the conveying direction F.

[0078] In the present embodiment, the backflow preventer 4 is further designed such that it is automatically closed in its normal position and opens automatically in the event of a wastewater pumping event, i.e. when the lifting station 2 is in operation and pumping wastewater in the pumping direction F.

[0079] For this purpose, the backflow preventer 4, which is designed in a tubular manner here, has in the present embodiment a movable sealing element which opens in the wastewater conveying direction F and closes against the wastewater conveying direction F and thus against the direction of gravity S. In the present embodiment of Fig. 1, this is realized by a movable sealing element in the form of a pivotable drop flap 15, which is designed as a rocker via a pivot axis A, so that a weight 17 arranged opposite the closing part 16 via the pivot axis A presses the drop flap into the closed normal position.

[0080] In addition, the weight 17 ensures that the flap valve 15 opens reliably under the force of the pumped wastewater during operation of the lifting station 2 and then quickly closes again to form a seal. In the closed position, the flap valve 15 interacts sealingly with its associated sealing seat 18. The sealing seat 18 describes a sealing plane D of the backwater valve 4. The closing part 16 of the flap valve 15 is designed as a ball-like buoyancy body in this embodiment. Fig. 2 shows a section through the backwater valve in Fig. 1 along the extension axis X of the downpipe section and here along the main extension axis Y of the backwater valve 4, in a plane parallel to the paper plane of Fig. 1. Due to the sectional plane chosen in Fig. 2, the flap valve 15 itself cannot be seen in this view.

[0081] As can be clearly seen in Figures 2 to 4, the backflow preventer 4 has a wastewater passage area widening 19 at the sealing plane D. The passage area widens abruptly, due to a jump in the clear width, in the wastewater conveyance direction F below the sealing plane D, which here is inclined to the vertical V. In this embodiment, the wastewater passage area widening 19 is approximately 90%. However, smaller percentage widenings of at least 25% are also conceivable.

[0082] Fig. 3 shows a sectional view as in Fig. 2, with the cutting plane perpendicular to Fig. 2, so that the movable sealing element, here the drop flap 15, can be seen in the closed normal position.

[0083] Here, the rocker-like drop flap 15 and the weight 17, which could also be called the closing weight, are clearly visible in cross-section. The drop flap 15 is in its normally closed position, and the lifting system 2 is correspondingly inactive.

[0084] Fig. 4 shows the view from Figure 3 with the drop flap 15 pivoted in a fully open position as may occur during operation of the lifting station 2, so that the pumped water moves in the direction of gravity S. In the fully open position, the ball-shaped closing part 16 is pivoted almost completely into a lateral escape space 20 of the backflow preventer housing 21, which is protected from the direct wastewater jet.

[0085] Fig. 5 shows a second embodiment of a wastewater lifting system 22 according to the invention in a view comparable to that of Fig. 1.

[0086] This embodiment differs from that of Fig. 1 essentially in the backflow preventer 23, which here features an alternative sealing element and an alternative geometry. In this embodiment, the downpipe section 11 is formed entirely by the permeable interior of the backflow preventer 23. The wastewater inlet nozzle 24 of the backflow preventer 23 also includes part of the curved pipe section 7, more precisely, part of the middle section 8 and the right-hand curved section 10.

[0087] In this embodiment, the backflow preventer 23 also has a ceiling mounting fixture 25 on its upper side, with which it is attached directly to the installation room ceiling 26, thus ensuring that the highest available point in the room is utilized. Fig. 6 shows a section through the backflow preventer 23 from Fig. 5, with the backflow preventer 23 shown in a closed position. The section runs along the extension axis X of the downpipe section 11 and thus along the main extension axis Y of the backflow preventer 23. The section plane lies in a plane parallel to the paper plane of Fig. 5.

[0088] As can be clearly seen in Figures 5 and 6, the backflow preventer 23 has the wastewater inlet nozzle 24 on its inlet side at a higher level, and a wastewater outlet nozzle 27 on its outlet side at a lower level. In this embodiment, both nozzles 24, 27 point transversely to the direction of gravity S, and thus here transversely to the main extension axis Y of the backflow preventer 23, more precisely, here both orthogonally to the main extension axis Y of the backflow preventer 23.

[0089] As can be further seen from Figures 5 and 6, the backflow preventer 23 forms the beginning of the downpipe section 11.

[0090] The movable sealing element of the backflow preventer 23 in this embodiment is an axially movable sealing tappet 28, which presses against its valve seat 29 by means of a spring element 35, spring-loaded against the direction of gravity S, and is closed in the normal position, as shown in Fig. 6. During operation of the lifting station 2, the sealing tappet 28 temporarily moves under the force of the pumped wastewater in the wastewater conveying direction F, thereby releasing the passage at the valve seat 29, which here describes the sealing plane D lying horizontally.

[0091] In this embodiment, the sealing plunger 28 is designed like a hollow diving bell, wherein the axial guide 28 of the sealing plunger 28 is arranged in an inner region 31 of the plunger 28 which is protected from the wastewater downstream.

[0092] As can be seen particularly in Fig. 7, in this embodiment, a wastewater passage area widening 32 is also realized at the sealing plane D, here a sudden horizontal widening in the clear width by approximately 100%, below the sealing plane D. However, smaller percentage widenings of at least 25% are also conceivable in other embodiments. The clear width in the horizontal direction jumps directly below the sealing plane D onto the curved inner wall of a water guide hood 33 surrounding the valve seat 29 in the wastewater conveying direction F. Fig. 7 shows the sealing tappet 28 in a maximally open position.

[0093] In previously described embodiments, the extension axis X of the downpipe section 11 according to the invention and thus also the main axis Y of the respective backflow preventer 4, 23 extends along the vertical V and runs in the direction of gravity S. In embodiments not shown, the extension axis X of the downpipe section 11 according to the invention and thus also the main axis Y of the respective backflow preventer 4, 23 can lie in a relatively acute angular deviation in the range from 0° to 20° to the vertical V, in particular in an angular deviation range from 0° to 5° to the vertical V.

[0094] In the aforementioned embodiments of the invention, said wastewater conveying line 3 is not ventilated from the lifting station 2 up to the point where it joins a hierarchically superior wastewater downpipe (not shown), for example the central wastewater downpipe of a building.

[0095] In further embodiments (not shown here), the wastewater conveying line 3 of the wastewater lifting system 1, 22 according to the invention is unventilated from the lifting system 2 up to the backflow preventer 4, 23, in particular at least up to the sealing plane D of the backflow preventer 4, 23.

[0096] In further embodiments of the aforementioned embodiments, the inner diameter of the wastewater conveying line 3 is at least 40 mm at any point.

[0097] The function of a wastewater lifting system according to the invention is briefly explained below using the wastewater lifting system 22 from Fig. 5 as an example.

[0098] When the wastewater lifting station 2 is inactive and the movable sealing element, here the sealing tappet 28, is in the closed normal position, in the embodiment of Fig. 5, the wastewater in the wastewater conveying line 3 from the lifting station 2 up to the top of the sealing level D in the backflow preventer 23 is generally present. However, in the uppermost area of ​​the curved line section 7, there are usually still air pockets from the previous operation of the lifting station 2 and its interaction with the backflow preventer 23.

[0099] The parts of the sealing tappet 28 below the sealing plane D as well as all guide parts 30 are therefore not located in the wastewater or are therefore not in a wastewater sump, but in a wastewater-free area.

[0100] During operation of the wastewater lifting station 2, triggered by wastewater containing faeces accumulating at the lifting station 2, the wastewater already standing above the lifting station 2, together with the newly accumulating wastewater, is pressed in the wastewater conveying direction F against the closed sealing tappet 28, so that the latter moves in the wastewater conveying direction F towards its maximum open position and thereby releases the flow at the valve seat 29.

[0101] The wastewater passage area expansion 32 creates a valve effect, accelerating the pumped wastewater, cleaning the valve area and the sealing tappet 28 and reducing the adhesion of contaminants. The wastewater is depressurized, and the resulting wastewater-air mixture falls downward in the direction of gravity S until it flows over the inclined base 34 of the backflow preventer 23 to the wastewater outlet nozzle 27 and further to the gradient pipe 13.

[0102] The moving parts or the guide 30 of the sealing tappet 28 are protected from the falling jet of the waste water and thus from contamination.

[0103] When the lifting station 2 stops operating, the spring-loaded sealing plunger 28 quickly closes again, effectively reducing backflow of the wastewater column toward or onto the lifting station.

[0104] Due to the increased wastewater velocities in the backflow preventer 23 during lifting operation, the backflow preventer 23 is particularly well flushed and kept clean.

[0105] If a backflow situation occurs due to wastewater coming from a hierarchically superior channel or from the main sewer system against the wastewater conveyance direction F, an air cushion is reliably formed below the sealing level D due to the sealing tappet 28 being closed as standard, so that the functionally relevant and movable components of the backflow preventer 23, such as the guide 30 of the sealing tappet, do not come into contact with the backflow wastewater.

[0106] As already mentioned at the beginning, the aforementioned effects significantly improve the reliability and longevity of the sewage lifting system 22 as a whole.

[0107] In the embodiment of the wastewater lifting system 1 shown in Fig. 1, the effects described above occur in a similar manner. Instead of a spring element 35, the sealing element, more precisely the drop flap 15, is pressed into the normally closed position by means of the weight 17. When opened under the wastewater pressure of the lifting system, the drop flap 15 pivots into the lateral escape chamber 20 and, when the lifting system 2 stops, quickly closes again due to the weight 17, effectively preventing the wastewater column from backing onto the lifting system.

[0108] In further embodiments not shown here, the backflow preventer according to the invention is open in its normal position and only closes in the event of a backflow situation. This can be achieved, for example, by the sealing tappet 28 in the embodiment of Fig. 5 not being spring-loaded, but by its diving bell shape open in the wastewater conveying direction F forming a buoyancy body which floats up and seals in a backflow situation, or is moved or sucked into the valve seat 29 by the negative pressure in the wastewater conveying line 3 when the wastewater column slides back towards the lifting station 2 when the lifting station is stopped. The same applies to the drop flap 15 from the embodiment of Fig.1, which in one embodiment can also be designed without a weight 17 and is thus open in the normal position, wherein the sealing element is designed, for example, as a voluminous buoyancy body which floats into the closed position in a backflow situation and is sucked into the sealing seat 18 when the wastewater column slides back towards the lifting station, thereby mitigating the backlash onto the lifting station 2. By being positioned in the downpipe section 11 of the wastewater conveying line 3, these embodiments also benefit from the advantages of better flushing, wastewater-free rest phases of the movable and functionally relevant parts and the possibility of positioning functionally relevant and contamination-prone components in a protected area.As further clarified by the above explanations, according to the present invention, an existing sewage lifting system can also be retrofitted with a backflow preventer in its downpipe, thereby improving it. The use of a backflow preventer for the aforementioned purpose is equally inventive.

Claims

Claims 1. Wastewater lifting system (1, 22), comprising a wastewater lifting plant (2) with a wastewater conveying line (3), wherein the wastewater lifting plant (2) is designed to pump wastewater through the wastewater conveying line (3) in the wastewater conveying direction (F) from a geodetically lower level to a geodetically higher drainage level, wherein the wastewater conveying line (3) has a riser section (6) in the wastewater conveying direction (F), a curved section (7) with a peak level (N) of the wastewater conveying line (3), and a downpipe section (11) in which wastewater moves in the direction of gravity (S), the wastewater lifting system (1, 22) further comprising a backflow preventer (4, 23) which allows wastewater to pass through in the wastewater conveying direction (F) and closes in the event of a wastewater backflow event, characterized in that the downpipe section (11) has the backflow preventer (4, 23).

2. Wastewater lifting system (1, 22) according to claim 1, wherein the backflow valve (4, 23) is designed to be automatically closed in a normal position and to open automatically in the event of a wastewater pumping event.

3. Wastewater lifting system (1, 22) according to one of the preceding claims, wherein in the backflow preventer (4, 23) by means of a wastewater passage area widening (19, 32) in the wastewater conveying direction (F) a transition from a pressure conveying to a pressureless gravity drainage is realized, in particular the wastewater passage area widening (19, 32) is realized at the sealing plane (D) of the backflow preventer (4, 23).

4. Wastewater lifting system (22) according to one of the preceding claims, wherein the wastewater inlet nozzle (24) and / or the wastewater outlet nozzle (27) of the backflow preventer (23) point transversely to the direction of gravity (S).

5. Wastewater lifting system (22) according to one of the preceding claims, wherein the downpipe section (11) is formed by the backflow preventer (23).

6. Wastewater lifting system (22) according to one of the preceding claims, wherein the backflow preventer (23) is fastened to the local ceiling (26), in particular by means of a ceiling mounting attachment (25) on its upper side.

7. Wastewater lifting system (22) according to one of the preceding claims, wherein the backflow preventer (23) forms the beginning of the downpipe section (11).

8. Wastewater lifting system (1) according to one of claims 1 to 7, wherein the backflow preventer (4) forms the end of the downpipe section (11).

9. Wastewater lifting system (1, 22) according to one of the preceding claims, wherein the backflow preventer (4, 23) has a movable sealing element (15, 28) which opens in the wastewater conveying direction (F) and closes against the wastewater conveying direction (F), in particular the movable sealing element (15, 28) opens and closes automatically.

10. A method for installing or improving a wastewater lifting system (1, 22), characterized in that a downpipe section (11) of the wastewater conveying line (3) of a wastewater lifting system (2) is designed or provided with a backflow valve (4, 23) which allows wastewater to pass through in the wastewater conveying direction (F) and closes in the event of a wastewater backflow event.

11. Method according to claim 10, wherein the backflow valve (4, 23) is automatically closed in a normal position and opens automatically in the event of a wastewater discharge event.

12. Method according to claim 10 or 11, wherein the backflow preventer (4, 23) is designed and / or installed in such a way that it realizes the beginning and / or the end of the downpipe section (11).

13. Method according to one of claims 10 to 12, wherein the backflow preventer (4, 23) has a wastewater passage area widening (19, 32) in the wastewater conveying direction (F), in particular at its sealing plane (D), wherein with the wastewater passage area widening (19, 32) in the wastewater lifting operation a transition from a pressure conveying to a pressureless gravity drainage is realized.

14. A method according to any one of claims 10 to 13, wherein the backflow preventer (23) is mounted on the local ceiling (26), in particular by means of a ceiling mounting attachment (25) on its upper side to the local ceiling.

15. Use of a wastewater backflow preventer (4, 23) in the downpipe section (11) of the wastewater conveying line (3) of a wastewater lifting system (1, 22) to improve system reliability, in particular said use of a wastewater backflow preventer (4, 23) having the wastewater backflow preventer features mentioned in one or more of the preceding claims.

Images