The object of the invention is a sewage lifting station with an intermediate separation of solid particles, equipped with at least one impeller pump, especially for sewage that contains raw domestic sewage with substantially diversified sizes and types of solid particles included in it.

Furthermore, it can be used in other pump installations, and its solutions can also be used when upgrading the existing reservoir sewage pumping stations.

Classical reservoir sewage pumping stations are well known and common that use sinkable sewage pumps that are automatically mounted on coupling elbows that are immersed in the sewage that is pumped by these pumps. In the sewage pumping stations constructed in this manner, the retention part of sewage is located in the same tank as immersible pumps, and the personnel have a direct contact with sewage each time they enter this tank, which makes the operation of the pumping station difficult. This tank is known as a wet tank or a wet chamber.

Increasingly smaller amounts of water that is used per one household dweller result in greater problems with odors and problems connected with a growing concentration of solid particles in sewage; for this reason, problems related to sewage transport become even more acute. In order to minimize these problems, it is usually costly methods of sewage aeration in a pressure pipeline that are used, or special chemical agents are dozed directly or indirectly to sewage pumped.

The use of sewage pumping systems that are installed on the bottom of a dry tank constitutes a reasonably good solution. These include sewage pumping installations both with impeller pumps and with air compressors. As compared with reservoir pumping stations, they practically guarantee an air-tight sealing of the installation and operation in much more hygienic conditions. In these sewage pumping installations, the retention part of sewage is located in a separate, tight and ventilated retention tank, which is most frequently positioned on the bottom of the dry tank, or is adjacent to the dry tank in such a manner that the personnel are not in a direct contact with sewage each time they enter this tank. This tank is also known as a dry chamber. When a dry tank is located in floodplains where it may be flooded, hermetic impeller pumps are used with engine cooling by pumping of a medium, or immersible impeller pumps are used, which are also adapted to work in dry conditions in the surrounding air. Hand pumps or portable immersible pumps serve the purpose of pumping out of sewage that poured out of the retention tank when replacing the pump or during an inspection of the fittings.

A particular variation of such pumping stations are those pumping stations that are located in a dry tank, with the use of at least one impeller pump with an intermediate separation of solid waste. An intermediate separation of solid particles included in sewage increases the reliability of pumps and makes it possible to use pumps with impellers with a smaller clearance for solid particles and higher efficiencies and, in particular, with greater raw sewage lifting heights. These pumping stations are known from the following patent descriptions: EP 0 846 810 Bl, PL 208 525 Bl and PL 195 925 Bl. The principle of the operation of a sewage pumping station with two pumps is that solid particles contained in raw sewage are preliminarily pre-treated in the separating unit and, as pre-treated, they go to the pre-treated sewage retention tank. Once the sewage reaches a specific level in the retention tank, the pump switches on and it pumps out the pre-treated sewage from the retention tank, until it has been almost totally emptied; at the same time, it washes out from the separator the previously separated parts. The moment the pump switches on, the inflow reflux valve on the raw sewage inflow switches on, and the valve on the feed side opens, and the pre-treated sewage that is pumped by the pump is pumped outside, for example to a pipeline. At the same time, the other inflow return valve is open and the sewage that has been pre- treated in the separating unit flows into the retention valve. These cycles repeat alternately.

The primary inconvenience of these solutions is the working volume of the separators being too small, in the area of sedimenting solid particles in particular. An abrupt inflow of sewage with high contents of solid particles, especially sedimenting ones, may quickly block the separating unit of the separator and cause a failure of the operation of the sewage lifting station. A displacement path of solid particles in the separator being too short hinders a failure-free operation of the station, as well. The designs of sewage lifting stations that are available on the market did not take into account the current changes in the concentrations of solid particles in sewage. The fact that the designs are not prepared to the present change in the abovementioned situation, and that there are economically unjustified remedial measures concerning the existing sewage lifting station designs that consist merely in an increase of this volume, have lead to investigations into a new sewage lifting station design, which additionally is to be economically and ergonomically justified.

Therefore, there is a need for a design of such a pumping installation that would meet the expectations on the part of water-sewage management operators and that would comply with the restrictive regulations concerning environmental protection in those areas where people reside near sewer installations, and concerning the provision of as hygienic conditions of the operation of this installation as possible, and taking in particular account its reliability and ergonomic operation.

The sewage lifting station according to the present invention possesses: - at least one impeller pump, into which raw sewage flows via an inlet pipe connected with an inflow non-return valve from which sewage flows away through a pressure pipe, - a retention tank for pre-treated sewage that is connected to the impeller pump through a suction pipe, - a solid waste separator, which is connected with the impeller pump pressure outlet on one side and with a pressure pipe on the other side, whereas the solid waste separator possesses a hydraulic connection with the inflow non-return valve, and it is located at least in part inside the external contour of the pre-treated sewage retention tank, which possesses a bottom, a side wall and a top cover and, according to the invention, it is characterized in that the solid waste separator is in principle in the form of a U- shaped pipe, and both ends of the solid waste separator are situated at the same side of the pre-treated sewage retention tank side wall. Preferably, the sewage lifting station may possess a set of two impeller pumps and two solid waste separators dedicated to them, which are located in such a manner that the hydraulic connections of the impeller pumps with the solid waste separator are more distant from each other than the hydraulic connections of the pressure pipes with the solid waste separator.

Preferably, the sewage lifting station possesses an inlet port of the solid waste separator, which is connected to the solid waste separator pipe in its central part.

Preferably, the pre-treated sewage retention tank possesses the shape of a cylinder sector, and its side wall possesses in principle a vertical flat wall, whereas by the side of the flat wall of the pre-treated sewage retention tank there are both ends of the solid waste separator and the entry to the inlet port, which are located in such a manner that the entry to the inlet port is situated between both ends of the solid waste separator.

It is preferred when in the entry to the inlet port is located in the sewage lifting station higher than both ends of the solid waste separator.

It is preferred when in the sewage lifting station, the separating set of the solid waste separator is installed on the side of the impeller pump exit.

It is preferred when in the lifting station, between the inlet pipe and the inflow non-return valve, an inlet distributor is located, which is Y-shaped, and which possesses an emergency overflow that is connected to the pre-treated sewage retention tank, and which possesses at least one inflow pipe, which connects the feed pipe with the inflow non-return valve.

It is preferred when in the lifting station, the Y-shaped inflow separator possesses a cleanout port with an inspection cover, which is situated in the symmetry axis of the inlet pipe.

It is preferred when in the lifting station, the emergency overflow is in the form of an overflow pipe that finishes with recesses that open upwards, which are covered from the top with an overflow cover, the said cover being screwed onto the top cover of the pre-treated sewage retention tank. In the solution according to the invention, two contradictions have been reconciled: the smallest cubature of the installation possible and at the same time an extension of the flow path of raw sewage in the separator, starting from the moment it flows out until it reaches the separating set and, at the same time, an improvement of the ergonomics of its operation.

The object of the invention is presented in a greater detail in the embodiments in the figures. Fig. 1 presents a side view diagram of the sewage lifting station, Fig. 2 presents the upper projection of the sewage lifting station from Fig. 1 with a broken-out section, and Fig. 3 presents diagrammatically the sewage lifting station that is built into the dry tank in the upper projection, Fig. 4 presents the projection of the sewage lifting station in the A-A section, while Fig.

5 presents the projection of the sewage lifting station in the B-B section, and Fig.

6 presents a projection of a fragment of the sewage lifting station in the C-C section from Fig. 3.

The sewage lifting station with intermediate solid waste separation that is presented in Figs. 1-6 possesses at least one impeller pump 1, to which an inflow of raw sewage is delivered through an inlet pipe 2, which carries raw sewage, connected with an inflow non-return valve 3 and from which a sewage flow is discharged through a pressure pipe 4. The sewage lifting station possesses the retention tank 5 of pre-treated sewage that is connected to an impeller pump 1 with a suction pipe 6, and it possesses the separator 7 of solid waste that is connected on one side with the pressure exit 8 of the impeller pump 1, and with a pressure pipe 4 on the other side. The separator 7 of solid waste possesses a hydraulic connection with an inflow non-return valve 3 and it is situated at least in part inside the external contour of the retention tank 5 of pre-treated sewage, which possesses a bottom 9, a side wall 10 and a top cover 11. The separator 7 of solid waste is in principle in the form of a pipe 12 that is U-shaped, and both ends of the separator 7 of solid waste are located at the same side of the side wall 10 of the retention tank 5 of pre-treated sewage. Owing to placing the pipe 12 of the separator 7 inside the retention tank 5 of pre-treated sewage, an elongation was possible of the pipe 12 of the separator while at the same time the dimensions of the sewage lifting station were reduced. Simultaneously, the site for its operation and the ergonomics of operation have been optimized. Owing to the elongation of the pipe 12, there is a more even distribution of sedimenting solid waste over a greater length, and thus a better protection is ensured of the separating set 14 against any jamming or breakdown, and the bend of the pipe 12 itself provides an additional protection of the separating set 14 against it being jammed with solid particles, especially during a large intensity of the raw sewage inflow. The sewage lifting station possesses a set of two impeller pumps 1 and two dedicated separators 7 of solid waste, which are located in such a manner that the hydraulic connections of the impeller pumps 1 with the separator 7 of solid waste are more distant from each other than the hydraulic connections of the pressure pipes 4 with the separator 7 of solid waste. The sewage lifting station also possesses an inlet port 13 of the separator 7 of solid waste, which is connected to the pipe 12 of the separator 7 of solid waste in its central part. The retention tank 5 of pre-treated sewage is of the shape of a cylinder sector, and its side wall 10 possesses in principle a vertical flat wall 10.1, whereas by the side of the flat wall 10.1 of the retention tank 5 of pre-treated sewage, there are both ends of the separator 7 of solid waste and the entry to the inlet port 13, which are located in such a manner that the entry to the inlet port 13 is situated between both ends of the separator 7 of solid waste. Owing to such an arrangement of the impeller pumps 1, the inflow non-return valves 3 and the pressure pipes 4, as shown in Figs. 2 and 3, there is a better use of space for operation in the dry tank of the sewage lifting station, and hence there is a more ergonomic operation. The entry to the inlet port 13 is situated higher than both ends of the separator 7 of solid waste, which facilitates a better drain of sedimenting solid waste to the pipe 12 of the separator, and on the side of the exit from the impeller pump 1, the separating set 14 of the separator 7 of solid waste is installed. This arrangement of the separating set 14 facilitates its operation with the impeller pump 1. Between the inlet pipe 2 and the inflow nonreturn valve 3, a Y-shaped inlet distributor 15 is located, which possesses an emergency overflow 16 connected to the retention tank 5 of pre-treated sewage, and which possesses at least one inflow pipe 17, which connects the inlet pipe 2 with the inflow non-return valve 3. The emergency overflow 16 serves the purpose of a momentary emergency separation of solid particles from raw sewage in the case of its excessive inflow and/or in the case of the separating sets 14 of the separator 7 being jammed. The Y-shaped inlet distributor 15 possesses an inspection port 18 with an inspection cover 18.1, which is situated on the symmetrical axis of the inlet pipe 2, and it serves the purpose of an inspection of the inlet distributor 15 and the inlet pipe 2. Owing to this solution, any large-size solid particles will be stuck in the inspection port 18 and will not reach the inflow pipe 17. The emergency overflow 16 is in the form of an overflow pipe 19 that finishes with recesses 20 that open upwards, which are covered from the top with an overflow cover 19.1, the said cover being screwed onto the top cover 11 of the pre-treated sewage retention tank 5. This solution of the emergency overflow 16 is simple in realization and easy in operation with respect to periodical separation of solid particles on it. Preferably, an elbow return valve with a knife gate valve as one piece is used on the pressure pipe 4, which is shown in Figs. 1, 3 and 4. In order to make periodic inspections of the interior of the retention tank 5 and an eventual replacement of the separator 7 possible, unscrewable hatches can be used, as shown with a dotted line in Fig. 1.

The principal operation of the sewage lifting station according to the invention does not depart from the operation of state-of-the art lifting stations. Raw sewage flows through the inlet pipe 2, and through the inlet distributor 15 it enters the inflow pipe 17, and then through the inflow non-return valve 3 it enters the separator 7, where through the pipe 12 it then enters the separating set. Sewage that is pre-separated in the separator 7, being without any larger solid particles, gets through the pressure exit 8 of the impeller pump 1 and the suction pipe 6 to the retention tank 5 of pre-treated sewage. Once the retention tank 5 has been filled with treated sewage to a specific level, the impeller pump 1 switches on and it pumps out pre-treated sewage from the retention tank 5. At the same time, it washes away the previously separated solid particles from the separator 7 until it has been almost entirely emptied. The moment the impeller pump 1 switches on, the inflow non-return valve 3 on the raw sewage inflow closes, and the return valve on the pressure side opens, and pre-treated sewage that is pumped by the impeller pump goes outside through the pressure pipe 4, e.g. to a pipeline. At the same time, the other inflow non-return valve 3 is open and sewage that has been pre-treated in the separating set 14 enters the retention tank 5. These cycles repeat alternately.

The figure does not present any detailed state-of-the-art solutions, e.g. control devices with various properties and principles of operation.

The embodiments presented above do not exhaust all the embodiment options and applications of the installation according to the invention covered with patent claims 1 to 9.