Title of Invention

WASTE WATER LIFTING SYSTEM FOR MONITORING THE LIQUID LEVEL WITHIN THE COLLECTING TANK FOR SEWAGE

Abstract

The invention relates to a waste water lifting system with a collecting tank (2) for liquids, in particular waste water, faecal matter or the like, and with a device for emptying the tank, in particular a pump (3) which is connected to a motor and is arranged as a motor and pump unit in an entirely or partially recessed manner in the tank (2). The tank (2) has at least one inlet and outlet pipe (4,5) for the liquids, and the waste water lifting system is provided with a device (10) for switching the pump (2) as a function of a liquid level (PA, PE, A) with in the tank (2). The tank floor (12) or at least a partial surface (12.1, 12.2) is designed to be elastically flexible as a function of the filling level of the tank. One or more sensors (15) are arranged on the outside (14) of the elastically flexible tank floor surface (12.1, 12.2) and measure the deformation thereof. The elastically flexible tank floor part (12.1, 12.2) is arranged at a distance from an installation surface (13).

Full Text

Description Waste water lifting system The invention relates to a waste water lifting system comprising a collecting tank for liquids, in particular sewage, excrement or the like, and comprising a device for emptying the tank, in particular a pump which is connected to a motor and which is arranged as a motor pump unit wholly or partially lowered in the tank, the tank has at least one inlet and outlet pipe, respectively, for the liquids, and the waste water lifting system is provided with a device for switching the pump as a function of a liquid level within the tank. Waste water lifting systems of this kind are frequently used as excrement lifting systems and are employed in buildings and plants when waste water to be conveyed accrues beneath a so-called backwash level. The backwash level is usually a height level of an external waste water system, which is disposed outside a building under a road. For a proper operation of such a waste water lifting system, devices for monitoring the liquid level within the tank are necessary in order to be able to ensure that the pump is switched on and off on time. Through DE-A 33 11 980, such a waste water lifting system for the collection and pumping-off of sewage water is known. To this end, the waste water lifting system has a collecting tank and a motor pump unit located therein, which receives its switching signals through a pneumatic control bell. This is constituted by a Pitot tube, the air volume of which, when a tank content is raised, is enclosed and thus generates a static pressure in the Pitot tube. This pressure is registered by a pressure sensor and its value converted into a fill level height of the respective tank. However, such dynamic pressure systems, which exist in a wide variety of forms, are susceptible to the sewage water, and its constituent parts, present within the tank. Since a failure of a relevant component of this kind is of fundamental significance for the entire system and the building whose waste it disposes, considerable servicing and maintenance works are necessary to ensure the functionality thereof. In order to prevent leakages or deposits within such a Pitot tube system, the tube must constantly be cleared in a complex manner by separate control elements or the above drawbacks can be prevented by the introduction of air bubbles. Alternatively thereto, float switches, as are known, for example, through DE-A 3 43 0 527, have gained market acceptance for the controlling of the pump. In dependence on the liquid level within the tank, a float-actuated switch triggers the necessary switch-on and switch-off motions of a pump. These float switches also, however, are restricted or jeopardized in terms of their function by deposits or solid constituents in the liquid. The problem on which the invention is founded is therefore to develop a level registration system by which the fill level in the tank can be reliably registered without difficulty, and complex, additional protective devices exposed to the liquid can be dispensed with. The solution of the problem provides that the tank floor, or at least a part-area of the tank floor, is configured such that it is elastically resilient as a function of the tank fill level, that one or more sensors are disposed on the outer side of the elastically resilient tank floor area and measure the deformation thereof. With this solution, the problem of fill level sensors becoming contaminated is easily circumvented. Since the sensors which register the degree of deformation of a tank floor part are fitted on the outer side of the tank, they are fully removed from the harmful influences of the waste water. As a result of the arrangement of the tank floor part at a distance from an installation area for the waste water lifting system, a cavity is formed therebetween. This cavity is simultaneously a protective space for the external sensors against external mechanical influences and prevents damage to the elastically resilient tank floor part. The tank floor or a part-area thereof is designed such that at least one sensor is disposed at a tank floor measuring point at which an evaluable deformation occurs when the tank is maximally filled. Similarly, it is provided that at least one sensor is disposed at a tank floor measuring point at which an evaluable deformation occurs when the tank is minimally filled. The generation of sensor signals, with which the necessary switch-on, switch-off or alarm points of a waste water lifting system, or of the pump connected thereto, and the dependence on the respective fill level in the tank, can be reliably registered, is thus ensured. The deformation of load-imposing tank, which deformation here maximally occurs at a measuring point, lies within the respectively permitted material values. This is achieved by an appropriate shaping of the tank floor or of a part thereof. It is likewise possible to arrange an elastically resilient element in a leaktight and flexibly held manner in the tank floor and to connect it to at least one sensor. A sensor signal above a respective fill level is processed by the evaluation units (known per se) of such waste water lifting systems for a pump control system. According to another embodiment, one or more sensors are exchangeably fastened. This can be effected by means of simple snap-fastening or clamping connections and simplifies manufacture, whilst at the same time making a sensor easy to exchange in a possible service. An illustrative embodiment of the invention is represented in the drawings and is described in greater detail below, wherein fig. 1 shows an installation diagram for a waste water lifting system, fig. 2 shows a view of the waste water lifting system, fig. 3 & 4 show views of sensor arrangements, and fig. 5 shows an enlarged representation of a floor. In fig. 1, a cross section through a building is shown, in the basement of which a sanitary device is represented. The sewage of the sanitary device and other liquids to be disposed of flow to a waste water lifting system 1 and are collected therein until a sufficiently high fill level for an ad hoc conveyance is reached. The waste water lifting system 1 comprises a liquid-tight and odor-tight tank 2 and a pump 3, disposed sealingly therein, in the form of a motor pump unit, which is designed for the smooth-running conveyance of such liquids. Via an inlet pipe 4, accrued waste water is led into the tank 2, and via an outlet pipe 5 in the form of a pressure line, is conveyed over a backwash level 6 in order to flow from there into a sewage system 7. In general, such a tank 2 is provided with a ventilation (not represented here), whereby a gas evacuation is achieved and the creation of an overpressure in the tank 2 is prevented. Such a ventilation port is generally run over the roof of a building in order to prevent odors from causing a nuisance. Fig. 2 shows in enlarged representation a side view of such a waste water lifting system according to the prior art. The tank 2 which collects the sewage is hermetically sealed in order to prevent its escape and prevent odor nuisances within a building. The tank 2 is connected to an inlet line 4 and to an outlet line 5, in which latter a non-return valve 8 and a shut-off valve 9 are disposed. Partially immersed in the tank 2 is an electrically driven pump 3. It pumps into the outlet pipe 5 and is only ever switched on when required. To this end, it is connected to a switching apparatus 10 for controlling and monitoring the operation of such a waste water lifting system. By way of example, a float switch 11 is shown in dashed representation as the prior art. Such a float switch disposed within the tank 2 is used to transmit a signal to the switching apparatus 10 when three tank fill levels PA, PE and A (shown in dash-dot representation) are reached, and from said switching apparatus a switching function for the waste water lifting system is triggered. The lowermost line PA here stands for the switching function "pump off". The pivotably mounted float switch then hangs down. As the liquid level increases, the float moves upwards until, at a tank fill level PE, it reaches a switching setting corresponding to the switching function "pump on" and causes the pump to be switched on by the switching apparatus 10. And when the uppermost, third tank fill level A is reached, a non-permitted operating state, an alarm function is triggered. If a greater quantity of waste water flows into the tank than can be pumped away by the pump, then the alarm function prevents the cellar rooms from being flooded by a backflow and prevents waste water from escaping from the inlets of the connected-up devices. This state can also arise in the event of a pump failure. Care should therefore be taken to ensure that such a float switch disposed within the tank is constantly ready for use. In contrast, fig. 3 shows as an improvement to the previous solutions an enlarged detail of the tank 2 in the form of a cross section through a tank floor 12. The floor 12 of the tank 2 has a part-region 12.1, which is disposed above and at a distance from an installation plane 13. As a result, between the installation plane 13 and the tank 2 resting thereon with the floor area 12, a wholly or partially closed- off cavity 16 is formed. This shields the resilient part-region 12.1 of the tank floor 12 from external influences. The part-region 12.1 of the tank floor 12 is of elastically resilient configuration and on its outer side 14 there are disposed one or more sensors 15. The distance between the sensor 15 mounted at the lowest point and the installation plane 13 is dimensioned such that, when a tank 2 is fully filled, a contact with the installation plane 13 is safely prevented. The respective degree of filling of a tank 2 acts, in the form of a column of liquid, deformingly upon the part-area 12.1 of elastically resilient configuration. The respective degree of deformation thereof is registered by at least one external sensor 15. Its signal is converted with the aid of the switching apparatus 10 into a fill level signal, is displayed and/or is used to control the pump 3. Due to a liquid level which is reached within the tank and due to the column of liquid resulting therefrom, the tank floor area is deformed or deflected differently. The orders of magnitude of these deformations lie within the permitted values of the material respectively used for the tank 2. The sensor 15 is thus affected by deformation works, which are used as a direct measure of the fill level within the tank 2. Since the sensor 15 is disposed in a cavity 16, formed between the installation plane 13 and the, in relation thereto, raised floor part 12.1, an additional protective space for the sensor 15 is obtained. The signal lines (not represented here) of the sensor 15 are likewise located completely outside the waste water lifting system and can therefore be connected without difficulty to the switching apparatus 10. The hitherto usual pipe bushings in the tank 2 are thus fully dispensed with. This constitutes an additional safety feature for a safe operation. Fig. 4 shows another embodiment of the floor area 12. Here, in the resilient tank floor part 12.1, a tank floor part 12.2 of elastically resilient configuration is additionally designed as a membrane inserted in a liquid-tight manner. This tank floor part 12.2 can consist of a rubber material, can be configured as plate consisting of an elastic plastics material, can be designed as a metallic membrane or as a combination of such materials. The respective liquid level in the tank 2 deflects the tank floor part 12.2 in the direction of the outer side 14. A sensor 15 disposed on the outer side 14 and operatively connected to the tank floor part 12.2 generates a sensor signal from the deflection. Fig. 5 shows the arrangement of the sensor 15 in an exchangeably designed housing 17, which with known means 18 can be fastened to the tank floor part 12.1. In the shown illustrative embodiment, it serves simultaneously to fasten the tank floor part 12.2. And the sensor 15 can be designed as an inductive system for a path measurement or as a piezoquartz for a pressure measurement. Patent claims 1. A waste water lifting system comprising a collecting tank (2) for liquids, in particular sewage, excrement or the like, and comprising a device for emptying the tank, in particular a pump (3) which is connected to a motor and which is arranged as a motor pump unit wholly or partially lowered in the tank (2), wherein the tank (2) has at least one inlet and outlet pipe (4, 5), respectively, for the liquids, and the waste water lifting system is provided with a device (10) for switching the pump (3) as a function of a liquid level within the tank (2), characterized in that the tank floor (12), or at least a part-area (12.1, 12.2) of the tank floor (12), is configured such that it is elastically resilient as a function of the tank fill level, in that one or more sensors (15) are disposed on the outer side (14) of the elastically resilient tank floor area (12.1, 12.2) and measure the deformation thereof. 2. The waste water lifting system as claimed in claim 1, characterized in that the elastically resilient tank floor part (12.1, 12.2) is arranged at a distance from an installation area (14). 3. The waste water lifting system as claimed in claim 1 or 2, characterized in that at least one sensor (15) is disposed at a tank floor measuring point at which an evaluable deformation occurs when the tank is maximally filled. 4. The waste water lifting system as claimed in claim 1, 2 or 3, characterized in that at least one sensor (15) is disposed at a tank floor measuring point at which an evaluable deformation occurs when the tank is minimally filled. 5. The waste water lifting system as claimed in claim 4, characterized in that an elastically resilient element (12.1, 12.2) is arranged in a leaktight and flexibly held manner in the tank floor (12) and is connected to at least one sensor (15). 6. The waste water lifting system as claimed in one of claims 1 to 5, characterized in that one or more sensors (15) are exchangeably fastened. The invention relates to a waste water lifting system with a collecting tank (2) for liquids, in particular waste water, faecal matter or the like, and with a device for emptying the tank, in particular a pump (3) which is connected to a motor and is arranged as a motor and pump unit in an entirely or partially recessed manner in the tank (2). The tank (2) has at least one inlet and outlet pipe (4,5) for the liquids, and the waste water lifting system is provided with a device (10) for switching the pump (2) as a function of a liquid level (PA, PE, A) with in the tank (2). The tank floor (12) or at least a partial surface (12.1, 12.2) is designed to be elastically flexible as a function of the filling level of the tank. One or more sensors (15) are arranged on the outside (14) of the elastically flexible tank floor surface (12.1, 12.2) and measure the deformation thereof. The elastically flexible tank floor part (12.1, 12.2) is arranged at a distance from an installation surface (13).

Documents:

01511-kolnp-2008-abstract.pdf

01511-kolnp-2008-claims.pdf

01511-kolnp-2008-correspondence others.pdf

01511-kolnp-2008-description complete.pdf

01511-kolnp-2008-drawings.pdf

01511-kolnp-2008-form 1.pdf

01511-kolnp-2008-form 2.pdf

01511-kolnp-2008-form 3.pdf

01511-kolnp-2008-form 5.pdf

01511-kolnp-2008-international publication.pdf

01511-kolnp-2008-international search report.pdf

1511-KOLNP-2008-(05-08-2014)-ABSTRACT.pdf

1511-KOLNP-2008-(05-08-2014)-ANNEXURE TO FORM 3.pdf

1511-KOLNP-2008-(05-08-2014)-CLAIMS.pdf

1511-KOLNP-2008-(05-08-2014)-CORRESPONDENCE.pdf

1511-KOLNP-2008-(05-08-2014)-DESCRIPTION (COMPLETE).pdf

1511-KOLNP-2008-(05-08-2014)-DRAWINGS.pdf

1511-KOLNP-2008-(05-08-2014)-FORM-1.pdf

1511-KOLNP-2008-(05-08-2014)-FORM-2.pdf

1511-KOLNP-2008-(05-08-2014)-OTHERS.pdf

1511-KOLNP-2008-(05-08-2014)-PETITION UNDER RULE 137.pdf

1511-KOLNP-2008-(05-11-2014)-CORRESPONDENCE.pdf

1511-KOLNP-2008-(05-11-2014)-FORM-1.pdf

1511-KOLNP-2008-(05-11-2014)-PETITION UNDER RULE 137.pdf

1511-KOLNP-2008-CORRESPONDENCE 1.2.pdf

1511-KOLNP-2008-CORRESPONDENCE 1.3.pdf

1511-KOLNP-2008-CORRESPONDENCE OTHERS 1.1.pdf

1511-kolnp-2008-form 18.pdf

1511-KOLNP-2008-INTERNATIONAL PRELIMINARY EXAMINATION REPORT.pdf

1511-KOLNP-2008-INTERNATIONAL SEARCH REPORT 1.1.pdf

1511-KOLNP-2008-OTHERS.pdf

1511-KOLNP-2008-PA.pdf

1511-KOLNP-2008-PCT REQUEST FORM.pdf

1511-KOLNP-2008-PRIORITY DOCUMENT.pdf

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