LU101566B1 - Centrifugal pump with an automatic valve - Google Patents

Abstract

The invention relates to a centrifugal pump (10) for conveying a fluid with a pump housing (16) forming a pump chamber (14), an impeller (18) being provided in the pump chamber (14) and an impeller in the pump housing (16) Suction opening (26) is provided for sucking the fluid into the pump chamber (14), a vent opening (30) is provided in the pump housing (16) behind the impeller (18) in relation to the suction opening (26), and wherein at the vent opening ( 30) an automatic valve (32) is provided through which air can escape from the pump chamber (14).

Description

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LU101566 |

Centrifugal pump with an automatic valve |

Technical area |

The invention relates to a centrifugal pump for conveying a fluid with one | Pump housing forming the pump chamber, an impeller in front of the pump chamber | is seen, in the pump housing a suction opening for sucking the fluid into the | Pump chamber is provided and in the pump housing based on the suction opening | a ventilation opening is provided behind the impeller.

Furthermore, the invention relates to | the use of the above centrifugal pump as waste water and / or sewage | Submersible pump.

Furthermore, the invention relates to a lifting system comprising a collector | container and the above centrifugal pump. | Background of the Invention |

In centrifugal pumps, a rotary movement of an impeller is used to convey a fluid.

The fluid to be conveyed enters a pump chamber of the

Centrifugal pump, is picked up by the rotating impeller and subsequently conveyed into a line section, which is also referred to as a pressure pipe.

Due to their robustness against fluids mixed with solids, circular pumps are used as sewage pumps, especially pumps in sewage lifting plants.

in which the wastewater is usually collected in a collecting tank for intermediate storage.

So that the fluid flows into the pump chamber | can flow in and feed the centrifugal pump with high efficiency, the centrifugal | pump must be vented.

For this purpose, it is common practice to provide ventilation openings in the pump chamber through which the air can escape from the pump chamber.

The ventilation opening | is usually located at the highest point of the pump room, when | Centrifugal pumps above the impeller. |

When the centrifugal pump is delivering, the pressure difference between the higher pressure inside the pump chamber and the lower pressure on the pump | On the side of the vent opening facing away from the pen space, a leakage flow of the fluid through the vent opening that has to be accepted.

The leakage flow of the fluid is usually routed away from the pump via a vent line or, in the case of waste water lifting systems, returned to the collecting tank.

However, when the centrifugal pump is in operation at low delivery heads and large volume flows of the fluid to be demanded, the effect can occur that the pressure conditions described above are reversed, so that a lower absolute pressure than the pressure prevails at the ventilation opening within the pump chamber on the side of the vent opening facing away from the pump chamber.

In the case of open systems, the pressure on the side of the vent opening facing away from the pump chamber generally corresponds to an ambient pressure of the pump or, in the case of closed sewage lifting plants, the pressure in the collecting tank of the sewage lifting plant.

The reverse pressure conditions lead to the fact that a reverse flow also occurs during the pump run, namely from outside the pump through the vent line and vent opening into the pump chamber.

For wastewater lifting plants, this means that, depending on whether the end of the vent line facing away from the vent opening is just above or below a filling level in the collecting tank, either air or fluid with the solids contained therein through the vent line into the pump room is promoted.

An entry of air into the pump room leads to a drop in performance of the centrifugal pump.

Furthermore, the entry of air leads to an undesirable increase in noise.

Solids in the fluid can block the vent line and / or the vent opening so that the actual venting process can no longer take place or can only take place insufficiently while the pump chamber is being filled, which also leads to a drop in performance. | _

| 3 LU101566 Description of the invention Based on this situation, it is an object of the present invention to improve a centrifugal pump and a lifting system of the type mentioned in such a way that the centrifugal pump or lifting system is quiet in operation and reliable without power input; breakage due to air entrainment and / or clogging of a ventilation system of a hydraulic system of the pump is working ..

This object is achieved by the features of the independent claims. Advantageous refinements are given in the subclaims.

Accordingly, the object is achieved by a centrifugal pump for conveying a fluid with a pump housing forming a pump chamber, an impeller being provided in the pump chamber, a suction opening for sucking the fluid into the pump chamber being provided in the pump housing, in relation to the suction - A ventilation opening is provided behind the impeller opening, and an automatic valve through which air can escape from the pump chamber is provided at the ventilation opening.

An essential point of the solution described in more detail below is that the automatic valve is arranged at the ventilation opening. The valve allows air to pass unhindered through the vent. When the valve is open, air can escape from the pump chamber via the ventilation opening, which leads to the pump chamber being vented. When the valve is closed, no air can pass through the valve and thus neither escape from the pump chamber via the ventilation opening nor enter the pump chamber via the ventilation opening. In the context of the invention, an automatic valve is understood to be a valve which opens and closes automatically without auxiliary energy. In other words, the opening and closing process of the valve is not made possible by electrical energy, but by mechanically provided energy. The mechanical energy for opening and closing the valve can be provided by the valve itself and / or by the medium flowing through the valve. The automatic valve is preferably designed in such a way that it is due to

4 | LU101566 | of pressure differences between a valve inlet side and a valve outlet side opens and / or closes.

In the present case, the valve inlet side is the side of the valve in the interior of the pump chamber at the vent opening.

The automatic valve enables air to escape from the pump chamber, which means that the centrifugal pump can properly ventilate the pump chamber so that fluid can flow through the suction opening into the pump chamber after each pumping process.

The valve thus enables air to flow from the valve inlet side to the valve outlet side.

The automatic valve ensures that the centrifugal pump can deliver with a high degree of hydraulic efficiency.

Furthermore, the automatic valve prevents air from flowing in the opposite direction, that is to say from outside the pump, via the vent opening into the pump chamber.

In other words, the valve prevents air from flowing from the valve outlet side to the valve inlet side.

Compared to pumps without an automatic valve, the hydraulic efficiency of the centrifugal pump according to the invention is constantly high, even with low delivery heights and large volume flows of the fluid to be conveyed.

Furthermore, undesirable noise development is avoided, so that the pump can be operated quietly.

The centrifugal pump can preferably be used for a hydraulic system in a building, for example in a sewage lifting system.

Accordingly, the fluid can also contain solids, the solids contained in the fluid being impurities of any kind, | for example, dirt, paper, feces or the like. | In the case of a centrifugal pump, the fluid is conveyed by rotating the impeller. | In this context, it is preferably provided that the impeller is connected to a drive motor via a motor shaft extending in the axial direction.

During operation, the fluid flows from outside the pump through the suction opening in the pump housing into the pump chamber in which the rotating impeller is located.

In addition to tangential acceleration of the fluid, a centrifugal force occurring in the radial direction is used to convey the fluid, so that centrifugal pumps are also referred to as centrifugal pumps.

The fluid is preferably conveyed from the pump chamber into a line section, which is also referred to as a pressure pipe.

For the purpose of venting the pump chamber, the centrifugal pump has the

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LU101566 vent opening.

The vent opening is preferably located at the highest point in the pump chamber.

The air escaping through the vent opening can have a fluid component. In many cases the suction opening of the centrifugal pump is located at the lowest point of the pump housing, so that the centrifugal pump can pump out the fluid as far as possible without large amounts of residual fluid remaining below the suction opening.

In such vertically installed centrifugal pumps, the axial direction of the motor shaft corresponds to the vertical direction.

In vertically installed centrifugal pumps, the ventilation opening is preferably above the height at which the impeller is attached to the motor shaft.

However, other constructions and setups of the centrifugal pump are also possible in which the motor shaft extends in the horizontal direction.

When installed horizontally, the suction opening is usually not at the lowest point of the pump housing.

When installed horizontally, the ventilation opening is preferably located next to the fastening point of the impeller on the motor shaft and on the side of the impeller facing away from the suction opening, based on the horizontal direction. | As already mentioned, the automatic valve allows air to escape from the pump chamber | can escape and prevents air from outside the pump from flowing into the pump chamber via the venting opening.

In principle, it is therefore possible that the | The valve opens due to the flow of air out of the pump chamber.

In this case, the valve would open when the pressure on the valve inlet side is greater than on the valve outlet side. However, according to a preferred development of the invention, it is provided that the valve is designed in such a way that it is open when the vent opening in the pump chamber the same or a higher pressure is present than an ambient pressure on the valve outlet side.

In other words, it means that before- | if the pressure on the valve inlet side and the valve outlet side is the same, the valve is open.

This enables the air to escape unhindered from the valve from the pump chamber when the pump is being conveyed.

The venting of the pump room is therefore without resistance, that is, an overpressure does not have to build up in the pump room, which opens the valve before the air can escape from the pump room. .

x. N . LU101566 As also known from the prior art; occurs when the centrifugal pump is promoted in | Purchase the leakage flow of the fluid to be taken from the pump chamber through the ventilation opening.

If - as is usual with wastewater lifting plants - the leakage flow of the fluid | Via a vent line from the pump into a collecting tank of the sewage lift | ; systems, the ambient pressure on the valve outlet side / the pressure in the collecting tank of the wastewater lifting system corresponds.

For open systems, | the ambient pressure on the valve outlet side the ambient pressure outside the | Pump, so usually normal pressure. | | With regard to the closing of the valve, according to a preferred development of the | Invention provides that the valve is designed such that it closes when in | The pressure in the pump chamber at the ventilation opening is lower than the pressure | ambient pressure on the valve outlet side.

In other words, the valve closes as soon as | The pressure on the valve inlet side is lower than on the valve outlet | page.

This means that when the pump is operating in the right-hand range of the characteristic curve, i.e. when the | Delivery head and large volume flows of the fluid to be demanded, prevented by the valve | air from outside the pump through the vent in the pump | space can get.

The valve preferably closes due to the fact that it closes for a short time adjusting the volume flow of air from the valve outlet side to the valve inlet side. | More preferably, the kinetic energy of the volume flow is used to move the valve | close.

In particular, it is provided that the valve closes as soon as the | The valve inlet side sets a lower pressure than on the valve outlet side and so on long remains closed, as these pressure conditions remain.

Such is the | Valve that prevents air from flowing back into the pump room. | According to a preferred development of the invention it is provided that the valve as | self-closing flap valve is designed.

The self-closing | is preferred The flap valve is at least partially open when the pressure on the valve inlet side exceeds the | Pressure on the valve outlet side, it is more preferably possible that a / flap of the flap valve through the from the valve inlet side to the valve outlet side | air passing through when the pump is vented and / or through the as leakage current |

LU101566 / penetrating fluid is opened further while the pump is operating. For example, if it comes | by operating the pump in the right-hand range of the characteristic curve, i.e. with a low delivery height | and large volume flows of the fluid to be conveyed, to the situation that the | If the pressure on the inlet side of the valve is lower than on the outlet side, the flow reverses briefly, which leads to the closing of the flap valve. Loading | The valve preferably has a dimensional rigidity such that the valve opens completely at the same pressure upstream and downstream of the valve. The self-closing flap valve | has the advantage that it is very robust due to its simple structure and without large | Effort can be produced.

/ As an alternative to the flap valve, the valve according to a preferred development is | of the invention designed as a duck bill valve. The duck-bill valve is preferred: a valve made of elastic material, the shape of which resembles the beak of a duck forms is. Preferably, the end of the duck that corresponds to the valve inlet side has Beak valve a shape corresponding to the vent opening. The other end: of the duckbill valve, that is, the end corresponding to the valve outlet side, shows preferably a flattened shape. The duck bill valve is preferably designed in such a way that it allows the air flow from the pump chamber through the vent opening without restriction. If, however, a flow reversal occurs, so that briefly air from. If the flow outside of the pump through the vent opening into the pump chamber, the valve closes and thereby prevents the backflow of fluid possibly contaminated with solids as well as air into the pump chamber. The duckbill valve has the advantage that it closes at very low pressure differences between the valve inlet side and the valve outlet side and has a very short response time. / In this context, according to a preferred development of the invention is before; seen that the valve is designed as a tubular valve with two tabs, which: lie against each other in the case of backflow and / or are placed against each other in the case of backflow. In other words, the end of the valve corresponding to the valve inlet side preferably has a tubular shape and the end corresponding to the valve outlet side has two tabs. The flaps are preferably two opposite flap-like flaps: End pieces of the hose jacket. The closing of the valve is preferably achieved by the lobes of the valve touching each other in the event of a return flow and thus closing a cross-section of the hose. In the event of a backflow, the flaps remain next to one another and the cross-section is closed, so that the valve prevents air from flowing into the pump chamber when the pressure conditions are reversed. The valve has the advantage that it responds to very small pressure differences between the valve inlet side and the valve outlet side and closes the cross-section very quickly. According to a further preferred development of the invention it is provided that the valve is made from an elastomer, preferably from a fluorinated elastomer. Since the valve for closing and opening preferably changes its shape, it has been shown to be advantageous if the valve is made from an elastomer. In particular, rubber, particularly preferably fluororubber (FKM), has proven to be advantageous. Alternatively, it is also possible to use other fluorinated elastomers, such as perfluorinated rubber (FFKM), tetrafluoroethylene / propylene rubbers (FEPM) and / or | fluorinated silicone rubber (FVMQ). The mentioned materials have the advantage that they are particularly resistant to chemicals, which is particularly favorable for sewage lifting systems due to the faeces. Furthermore, the mechanical properties, in particular the deformability and processability of the materials, are particularly suitable for producing the automatic valve. In addition, the elastomer can be made from other elastic materials. With regard to the design of the automatic valve, a preferred development of the invention provides that a wall thickness of the valve decreases from the valve inlet side to the valve outlet side. The decreasing wall thickness gives the mate | rial of the valve the necessary flexibility to close or open. The wall thickness on the valve inlet side is preferably 2 mm and on the valve outlet side 0.4 mm, more preferably 0.2 mm. Furthermore, it is preferably provided that the cross section of the valve is circular on the valve inlet side and circular, elliptical, almond shaped and / or lenticular on the valve outlet side. The diameter of the circular valve outlet side is preferably greater than the diameter of the elliptical, almond-shaped and / or lenticular valve outlet side. Furthermore, it is preferably provided that the valve has a conically decreasing shape, in which the diameter of the

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. LU101566 Valve inlet side to valve outlet side steadily reduced. The conical shape preferably has a slope angle of 3 degrees. In principle, the valve can be attached directly to the side of the vent opening facing away from the pump chamber. Alternatively, according to a preferred development of the invention, provision is made for a ventilation channel integrated into the pump housing or a ventilation hose connected to the pump housing to be provided between the valve and the ventilation opening. A ventilation hose between the ventilation opening and valve increases the flexibility of the centrifugal pump. The ventilation hose is preferably flexible, so that, in particular in the case of waste water lifting plants, the loss flow can be returned to the collecting tank of the waste water lifting plant through a separate opening in the collecting tank. Alternatively, the ventilation channel integrated in the pump housing simplifies the handling and robustness of the pump. The integrated ventilation channel preferably leads from the ventilation opening | 15 away to an outside of the centrifugal pump. Due to the integration of the ventilation channel in the pump housing, the ventilation channel can hardly break away from the pump housing. According to a preferred development of the invention, the centrifugal pump has a drive motor, the impeller being in operative connection with a motor shaft of the drive motor. The rotary movement of the impeller, which is responsible for conveying the fluid, is preferably passed on from the drive motor to the impeller via a motor shaft extending in the axial direction. In this connection it has proven to be advantageous if the suction opening is designed concentrically to the axis of the motor shaft. The suction opening is thus also arranged concentrically to the impeller. The pump housing is also preferably attached to a motor flange of the drive motor. | The centrifugal pump according to the invention is basically suitable for pumping any fluid. Due to its robustness against solids and chemicals, the centrifugal pump is particularly suitable for use as a waste water and / or submersible sewage pump. Dirty water and / or sewage submersible pumps are used in particular

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| LU101566 for pumping dirty water, for example from floods, in flooded construction pits, in laundry rooms, in muddy pits, in biotopes and / or garden ponds, from seepage shafts and in basements, and especially for pumping water with various degrees of contamination such as stones, Mud rubble or | 5 feces. The proposed use makes it possible to ensure low-noise operation and reliable venting of the pump chamber of the dirty water and / or sewage submersible pump. In addition, the centrifugal pump can also be used for heating with radiators, radiator heating, underfloor heating, ceiling cooling, water circulation in a drinking water system or a drinking water system with a storage tank charging system, whereby the above list is not exhaustive, but further here not mentioned types of systems may be included. Furthermore, the object is achieved by a lifting system comprising a collecting container and a centrifugal pump as described above, wherein the centrifugal pump can be connected to the collecting container in such a way that the suction opening faces an interior of the collecting container and wherein the automatic valve can be connected to the collecting container is. In lever systems in particular, it can be advantageous if the automatic valve is not attached directly to the ventilation opening, but rather the ventilation channel integrated in the pump housing or the ventilation hose connected to the pump housing is provided between the valve and the ventilation opening. In this way, the valve is easily accessible and can be easily guided back into the collecting container and attached to it.

In principle, it is possible for the collecting container of the lifting system to have an opening which is designed to correspond to the pump housing. The opening of the collecting container can be closed by applying the pump to the opening, the suction opening of the centrifugal pump advantageously facing the interior of the collecting container. In this form in particular, it is advantageous if the flexible ventilation hose is provided between the valve and the ventilation opening. This ms EEE enables the valve to be attached to a further opening on the collecting container and thus to guide the leakage flow back into the collecting container.

Alternatively, it is possible for at least part of a container wall of the collecting container to be formed by the pump housing having the suction opening.

In this case it can be provided that the container wall is shaped in such a way that it forms a lower part of an at least two-part pump housing.

The opening in the container wall is therefore the suction opening of the centrifugal pump.

In this form in particular, it is advantageous if the ventilation channel integrated into the pump housing is provided between the valve and the ventilation opening.

The integrated ventilation channel preferably leads away from the ventilation opening to an outside of the centrifugal pump, which is preferably also formed by the container wall.

In this way, the automatic valve can be mounted directly on the container wall and the leakage flow can be fed back into the collecting / container.

Due to this construction, the lifting system has a very compact shape.

According to a preferred development of the invention it is provided that a drive / drive motor of the centrifugal pump is arranged at least partially outside of the collecting container.

It has proven to be advantageous, in particular with regard to the maintenance of the lifting system, if the drive motor is arranged at least partially outside of the collecting container.

The drive motor is preferably positioned completely outside of the collecting container.

Further embodiments and advantages of using the centrifugal pump and / or the lifting system result for the person skilled in the art in analogy to the previously described centrifugal pump.

Brief description of the drawings

The invention is explained in more detail below with reference to the accompanying drawings using a preferred exemplary embodiment. |

In the drawings: FIG. 1 shows a schematic sectional view of a centrifugal pump in a lifting system according to a preferred embodiment of the invention, FIG. 2 shows a perspective view of an automatic valve of the centrifugal pump from FIG. 1, FIG. 3 shows a schematic sectional view of a centrifugal pump in a lifting system an alternative embodiment of the valve according to a further preferred embodiment of the invention, and | 4 shows a schematic sectional view of a centrifugal pump in a lifting system according to a further preferred exemplary embodiment of the invention.

Detailed description of the working examples; FIG. 1 shows a schematic sectional view of a centrifugal pump 10 in a lifting system 12 according to a preferred exemplary embodiment of the invention. The centrifugal pump 10 has a pump housing 16 that forms a pump chamber 14. Inside the pump | An impeller 18 is arranged in the pen space 14. The impeller 18 is connected to a drive motor 24 of the centrifugal pump via a motor shaft 22 extending in the axial direction 20 25 10 connected. The pump housing 16 has a suction opening 26 concentric to the axis 20 of the motor shaft 22, through which a fluid can flow into the pump chamber 14. From | the rotational movement of the impeller 18 is detected, the fluid is conveyed into a pressure port 28 (only; shown in Figure 4). The suction opening 26 of the centrifugal pump 10 is located at the lowest point of the pump housing 16, and the axial direction 20 of the motor shaft 22 | 30 corresponds to the perpendicular direction. Furthermore, the pump housing 16 of the centrifugal pump 10 | Relative to the suction opening 26 behind the impeller 18, a vent opening 30. ; In the centrifugal pump 10 in Figure 1, the vent opening 30 is at the highest point of the

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| 13 LU101566 | Pump chamber 14 and above the height at which the impeller 18 is attached to the motor shaft 18. An automatic valve 32 through which air can escape from the pump chamber 14 is provided at the ventilation opening 30. In the present case, the valve 32 connects to the vent opening 30 via a flexible vent hose 34.

; ; The lifting system 12 also has a collecting container 36 which can be connected to the centrifugal pump 10. To connect the centrifugal pump 10 to the collecting container 36, a container wall 38 of the collecting container 36 has an opening which is designed to correspond to the pump housing 16. In the here preferred embodiment | 10 centrifugal pump 10 and collecting tank 36 are connected in such a way that the suction opening 26 | of the centrifugal pump 10 faces an interior of the collecting container 36. Furthermore: FIG. 1 shows that the valve 32 is placed in a further opening of the collecting container 36 so that the ventilation opening 30 is connected to the interior of the collecting container 36 via the venting hose 34 and the valve 32. In the present case, the side of the valve 32 which faces the ventilation opening 30 corresponds to a valve inlet input side 40 and the side of the valve 32 which faces the interior of the collecting container 36 is a valve output side 42; FIG. 2 shows a perspective view of the valve 32 from FIG. 1. The valve 32 is designed as a duck-bill valve 32b, FIG. 2 showing the valve 32b in the open state; represents. The cross section of the valve 32b on the valve inlet side 40 is in the present case cylindrical and corresponding to the cross section of the ventilation hose 34 | tet. The cross section of the valve 32b on the valve outlet side 42 is almond in the present case shaped and slightly smaller than the cross section of the valve inlet side 40, the valve 32b | 25 thus has a conical shape, an angle of inclination being 3 degrees. Furthermore | takes a wall thickness 44 from the valve inlet side 40 to the valve outlet side 42 of | 4 mm down to 0.4 mm. The valve 32b faces one another on the valve outlet side 42 opposite tabs 46, which are formed from a lateral surface of the valve 32b: are. The present valve 32b is made of FKM. | 30 | FIG. 3 shows a schematic sectional view of the centrifugal pump 10 in the lifting system 12 | with an alternative embodiment of the valve 32 according to a further preferred |

; 14 LU101566 embodiment of the invention. In comparison to the duck bill valve 32b from FIGS. 1 and 2, the valve 32 in FIG. 3 is designed as a self-closing flap valve 32a. The cross section of the valve 32a in FIG. 3 is circular for the valve inlet side 40 as for the valve outlet side 42, the diameter being the same size. A circular flap 48 is located on the valve outlet side 42.

As can also be seen in FIG. 3, the valve 32a is not on a flexible vent ventilation hose 34 attached, but to one integrated into the pump housing 16; Ventilation channel 50. Analogously to FIG. 1, the valve 32a also opens into the collecting container 36 of the lifting system 12. In contrast to FIG. 1, in the collecting container 36 in FIG. 3, at least part of the container wall 38 is from the pump housing having the suction opening 26 16 formed. The container wall 38 is shaped in such a way that it forms a lower part of the at least two-part pump housing 16. The in the pump housing 16 | The integrated ventilation channel 50 leads from the ventilation opening 30 in the pump chamber 14: 15 away to an outside of the centrifugal pump 10, which is also separated from the container wall 38; is formed.

FIG. 4 shows a schematic sectional view of the centrifugal pump 10 in the lifting system 12, according to a further preferred embodiment of the invention. In FIG. 4, the valve 32 is designed as a duck bill valve 32b analogously to FIGS. 1 and 2, analogously to | FIG. 3, the valve 32b is mounted on the ventilation channel 50 integrated in the pump housing 16. The collecting container 36 is also constructed analogously to the lifting system 12 in FIG. In FIG. 4 it can be seen that the impeller 18 is an impeller 18 that is open on one side and the centrifugal pump has a generous pump chamber 14 with a large; 25 suction opening 26 has. It can also be seen that the through the suction opening 26 in | The fluid sucked into the pump chamber 14 is mainly conveyed into the pressure port 28 by radial flow. Due to the impeller 18, which is open on one side, the spacious | Pump chamber 14 and the generous diameter of the pressure port 28 is the circular | pump 10 particularly suitable for conveying fluids mixed with solids.

| The exemplary embodiments described are merely examples that can be modified and / or supplemented in many ways within the scope of the claims. Every feature

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| 4% 15 LU101566 that was described for a specific exemplary embodiment can be used on its own or in combination with other features in any other exemplary embodiment.

Each feature that has been described for an exemplary embodiment of a specific category can also be used in a corresponding manner in an exemplary embodiment of a different category.

List of reference symbols

Centrifugal pump 10

Lifting station 12 Pump room 14 | Pump housing 16 | Impeller 18 | Axial direction 20 / motor shaft 22 | Drive motor 24 | Suction opening 26 | Pressure port 28 | Vent 30 / valve 32 | Flap valve 32a | Duck bill valve 32b | Vent hose 34 | Collection container 36 | Tank wall 38 valve inlet side 40] valve outlet side 42 | Wall thickness 44 flap 46 flap 48; Vent channel 50

Claims (14)

° claims 1. Centrifugal pump (10) for conveying a fluid with a pump housing (16) forming a pump chamber (14), an impeller (18) being provided in the pump chamber (14) and a suction opening (26) in the pump housing (16) for Suction of the fluid into the pump chamber (14) is provided, in the pump housing (16), based on the suction opening (26) behind the impeller (18), a ventilation opening (30) is provided, and at the ventilation opening (30) automatic valve (32) is provided through which air can escape from the pump chamber (14). 2. Centrifugal pump (10) according to the preceding claim, wherein the valve (32) is designed such that it is open when in the pump chamber (14) at the vent opening | 15 (30) the same or a higher pressure is present as an ambient pressure on a valve outlet side (42). 3. centrifugal pump (10) according to one of the preceding claims, wherein the valve (32) is designed such that it closes when a lower pressure is present in the pump chamber (14) at the venting opening (30) than an ambient pressure on one Valve outlet side (42). 4. Centrifugal pump (10) according to one of the preceding claims, wherein the valve (32) is designed as a self-closing flap valve (32a). 5. Centrifugal pump (10) according to one of the preceding claims, wherein the valve (32) is designed as a duck bill valve (32b). 6. Centrifugal pump (10) according to one of the preceding claims, wherein the valve (32) is designed as a hose-shaped valve (32) with two tabs (46) which lie against one another when the flow is backflow and / or when there is a backflow. 7. centrifugal pump (10) according to any one of the preceding claims, wherein the valve (32) is designed from an elastomer, preferably from a fluorinated elastomer. 8. Centrifugal pump (10) according to one of the preceding claims, wherein between the valve (32) and the vent opening (30) a vent channel (50) integrated into the pump housing (16) or a vent hose connected to the pump housing (16) ( 34) is provided. 9. Centrifugal pump (10) according to one of the preceding claims, with an an | 10 drive motor (24) and the impeller (18) in operative connection with a motor shaft | (22) of the drive motor (24) is at a standstill. ; 10. Centrifugal pump (10) according to one of the two preceding claims, wherein the | Suction opening (26) is designed concentric to the axis (20) of the motor shaft (22). ; 15 | 11. Use of a centrifugal pump (10) according to one of the preceding claims as; Dirty water and / or submersible sewage pump. 12. Lifting plant (12) comprising a collecting tank (36) and a centrifugal pump (10); 20 according to one of the preceding centrifugal pump claims, wherein the centrifugal pump (10); can be connected to the collecting container (36) in such a way that the suction opening (26) has a; Interior of the collecting container (36) is facing and wherein the automatic valve (32) | can be connected to the collecting container (36). | 25th 13. Lifting plant (12) according to the preceding claim, wherein at least a part; a container wall (38) of the collecting container (36) from which the suction opening (26) opens facing pump housing (16) is formed. | 14. Lifting plant (12) according to one of the preceding lifting plant claims, wherein a; 30 drive motor (24) of the centrifugal pump (10) at least partially outside of the collecting | container (36) is arranged. DOES Ea