Vacuum pump with suction nozzle assembly including check valve for a fail-safe water reserve

Abstract

Vacuum pump (1), in particular a self-priming vacuum pump (1), as a component of a vacuum wastewater system for emptying and flushing toilets, urinals and the like, with a collecting inlet line (3a) which is connected to an inlet (3b) in a housing (2) of the vacuum pump (1) and which is closed inside the housing (2) by a check valve (6) when the vacuum pump (1) is not in operation, optionally with a cutting device which is axially arranged and which comminutes solid substances in the wastewater, further comprising an axially arranged screw spindle which, when rotated, forms a water ring necessary for generating the vacuum and draws in the wastewater by means of vacuum, further comprising an outlet and a drive motor, characterized in that the vacuum pump (1) ▪ comprises a suction nozzle (4) arranged in the inlet (3b), which is configured such that the suction nozzle (4) is always in fluidic contact with an outer diameter (4b) of a water reserve (5); ▪ and the check valve (6) is arranged at an angle between 1° and 90° relative to a vertical axis of the inlet-suction port transition (7) and fully seals the suction port (4), wherein the suction port (4) is further arranged such that, in the event of a leak in the check valve (6), none of its inner diameters (4a) can come into fluidic contact with a level of the water reserve (5), and the suction nozzle (4) is arranged at a height to the water level that ensures a sufficient water reserve (5) for suction under all operating conditions.

Description

Technical field

[0001] The invention relates to the field of vacuum technology, in particular vacuum pumps for use in vacuum systems for sanitary facilities such as toilets and urinals. Such sanitary facilities are used especially in vehicles and means of transport with special conditions, for example on ships, airplanes and trains. Description

[0002] The present invention discloses a vacuum pump with a suction nozzle arrangement with a check valve for a fail-safe water reserve, in particular a self-priming vacuum pump in which an undesirable loss of the water reserve is reliably prevented.

[0003] Vacuum pumps are known in the prior art in which the check valve is usually positioned below the water reservoir level. It has been found that in such pumps, particularly after extended periods of inactivity and due to leaks in the check valve, a complete loss of the water reservoir can occur. The water is then drawn back into the vacuum line via the leaking check valve, rendering the pump inoperable.

[0004] One object of the present invention is therefore to provide a vacuum pump with a specific suction nozzle arrangement including a check valve that avoids these disadvantages and always ensures a sufficient water reserve for safe pump operation.

[0005] To solve this problem, the invention proposes a vacuum pump, in particular a self-priming vacuum pump, comprising an inlet arranged above the level of a water reservoir, which is in fluidic contact with the water reservoir, particularly during the pumping process, a downward-facing suction nozzle specifically arranged in this inlet, and a check valve which is arranged at an angle between 1° and 90° to a vertical axis of the suction nozzle and the inlet and which covers the inlet and the suction nozzle in a closable manner. According to the invention, the suction nozzle is arranged such that, in the event of a leak in the check valve, it can only come into fluidic contact with the level of the water reservoir with its outer diameter, but not with its inner diameter, thus effectively preventing a loss of the water reservoir.

[0006] Preferably, the vacuum pump according to the invention comprises a base body with an inlet and a suction nozzle inserted therein, wherein the check valve is attached to the inserted suction nozzle. The suction nozzle with the check valve mounted thereon is preferably inserted into the base body from below and secured by a flange nut. Two O-rings serve to provide a reliable seal between the base body and the insert including the suction nozzle, of which a first O-ring provides a radial seal and a second O-ring provides an axial seal.

[0007] Furthermore, according to the invention, the suction port is preferably rotatable by at least 180°, more preferably by at least 270°, and most preferably by 360° in the base body to ensure optimal alignment of the check valve depending on the requirements of the vacuum pump. In a particularly preferred embodiment, the check valve is arranged such that it closes automatically due to its own weight, i.e., by gravity. It has proven particularly advantageous if the angle between the vertical axis of the suction port and the check valve is 10 to 14°, preferably 11 to 13°, more preferably about 12°, and most preferably 12°.

[0008] This arrangement of the suction port and the check valve according to the invention reliably prevents the pump, and in particular the water reserve, from emptying in the event of leaks, thus ensuring a sufficient water reserve at all times, which guarantees the safe and continuous operation (priming and running) of the pump. Due to these design features, the vacuum pump according to the invention can, in one embodiment, be described as "self-priming". In a preferred embodiment, the check valve is closed solely by gravity, according to the invention.

[0009] Another technical advantage of closing the check valve by gravity according to the invention can be summarized as follows: In state-of-the-art vacuum pumps, the check valve is typically closed by a vacuum in the suction line when the vacuum pump is switched off. It follows that the check valve is also open when water is being pumped via the pressure line. As a result, the water being pumped constantly attempts to flow towards the area of ​​negative pressure. Assuming a typical negative pressure of -0.9 bar, this corresponds to a distance of approximately 9 m. In practice, it has been found that the sum of the suction head and the discharge head must not exceed 9 m with such pumps.

[0010] This is not observed with the check valve arranged according to the invention. The check valve arranged according to the invention only opens when there is more negative pressure in the pump than in the rest of the system. Conversely, it closes as soon as the negative pressure in the system is greater than in the pump itself. Additionally, the check valve according to the invention closes as soon as water is to be pumped to a great height, i.e., above 6 m according to the invention. With the check valve arrangement according to the invention (which preferably closes purely by gravity), it is possible for the first time for the sum of the suction head and the discharge head to be greater than 9 m. Exemplary tests by the inventor have shown that in this way, water can be drawn upwards by 6 m and pushed upwards by 6 m with the vacuum pump, resulting in a total water movement over a distance of 12 m. This is solely due to the check valve arrangement according to the invention.

[0011] The invention thus provides a vacuum pump which, compared to known pumps, offers the advantage of remaining permanently functional and, in particular, being ready for immediate use even after long periods of inactivity. Detailed description

[0012] Vacuum pumps for a vacuum wastewater system with multiple wastewater sources are known, among other places, from EP 0 454 794 B2 and WO 2012 / 115 521 A1.

[0013] Such vacuum wastewater systems operate discontinuously and are only activated when needed; i.e., the vacuum pump motor is only switched on when required.

[0014] To ensure the system functions reliably and the vacuum pump can always generate a vacuum, it is advisable, or even necessary, to maintain a vacuum within the system and to continuously hold a specific volume of water (a so-called "water reserve") in the vacuum pump. The latter is necessary, for example, to build up the water ring required for vacuum generation in the area of ​​the screw spindle. If there is no or too little water in the vacuum pump, this leads to operational failures, requiring refilling, which incurs additional costs. This also results in downtime and is therefore economically disadvantageous.

[0015] To prevent water loss, state-of-the-art technology uses valves that block the supply line to the vacuum pump and, if necessary, also the outlet from the vacuum pump when not in operation.

[0016] As can be seen from the cited EP 0 454 794 B2 and WO 2012 / 115 521 A1, the inlet line with inlet nozzle located at the top of the vacuum pump can be closed inside the housing by a flap valve, preferably a rubber flap. When wastewater flows into the housing, this flap hangs down – thus not obstructing the flow – and is drawn in by the negative pressure in the inlet system when the vacuum pump is switched off, provided the check valve, preferably a rubber flap, is in contact with the inlet nozzle after the pump has been switched off, thus sealing it.

[0017] It has been shown that, particularly after extended periods of inactivity, the functionality of these cost-effective rubber flap valves is impaired. Specifically, the necessary seal of the inlet is no longer achieved because the rubber flap sags downwards due to gravity and no longer seals against the inlet. As a result of this, and / or due to other factors, these check valves become leaky – especially if they are made of rubber.

[0018] Therefore, within typical vacuum pumps, such as those described in DE 10 2018 001215 A1, a complete loss of the water reserve in the pump can occur under certain circumstances. This loss of water reserve results from leaks at the check valve of a butterfly valve, and is observed predominantly in vacuum pump systems. These vacuum systems are characterized by long pauses or periods of inactivity between pump cycles. Since, in these prior art arrangements, the check valve is located entirely below the water surface, the water is drawn back into the vacuum line through the leaks and is lost. However, the presence of a check valve is technically indispensable.

[0019] One object of the invention is therefore to ensure that a sufficient water reserve is available in the pump even if a check valve leaks and retains a non-return valve. According to the invention, this should be guaranteed even after extended periods of operation and prolonged downtime, thus eliminating the need for regular repairs and replacements of the non-return valves, e.g., made of a rubber material. At the same time, it should be ensured that sufficient water is always present in the vacuum pump as a water reserve, e.g., for reliable start-up and rapid vacuum build-up, but also when there is no vacuum or pumped medium in the suction line.

[0020] Therefore, a key effect of the vacuum pump according to the invention is that a sufficient water reserve is ensured under all operating conditions, even in the event of leaks in / at the check valve. This problem is solved by the features of claim 1, in particular by the arrangement according to the invention consisting of a suction port and a check valve; advantageous embodiments are the subject of the dependent claims.

[0021] According to the invention, a new design and arrangement of an inlet for a vacuum pump, in particular a self-priming vacuum pump, is provided, comprising a tubular base body as an inlet and a suction port inserted therein such that, in the event of a leak in the check valve, the water reserve only contacts an outer diameter of the suction port, but simultaneously does not contact an inner diameter of the suction port. This is made possible by the inlet-suction port device according to the invention in combination with the arrangement of a check valve disclosed herein.

[0022] In a preferred embodiment, following the installation of the check valve, the insert, including the suction port, is inserted into the base body from below. The insert is secured, for example, by means of a flange nut. The inlet-suction port assembly is sealed by at least two O-rings, with the base body (serving as the inlet) and the suction port insert being sealed by these O-rings. One O-ring seals radially, and the second seals axially. The suction port insert itself is rotatable within the base body by at least 180°, more preferably by at least 270°, and even more preferably by at least 360°. This ensures optimal alignment of the check valve according to the technical requirements of the respective vacuum pump.

[0023] The inventive arrangement of the check valve on the suction nozzle insert is designed such that, in the event of a leak in the check valve, the pump is prevented from emptying and a new priming process is always possible without additional refilling of the water reserve. The key feature of the invention is that the arrangement, consisting of the base body as the inlet, the suction nozzle insert, and the check valve, is designed in such a way that no fluidic connection is possible between the inner diameter of the suction nozzle and the water reserve in the inlet (i.e., not to an inner opening of the suction nozzle insert). This is only permitted for the outer diameter of the suction nozzle insert. Therefore, even if the check valve leaks, the reserve water cannot be lost through the suction nozzle insert. Water wetting in the inner diameter of the suction nozzle insert is impossible.The amount of water that always remains is therefore sufficient for the safe operation of the pump.

[0024] Consequently, the outer diameter of the suction nozzle insert is located within the pump at a point that is always reliably wetted with water, thus ensuring the pump's safe operation. Simultaneously, the inventive arrangement of the check valve on the suction nozzle insert ensures that the weight acting upon it closes the check valve (due to gravity). The angle of the check valve to the vertical axis of the inlet suction nozzle assembly should be between a maximum of 90° and a minimum of 1°. In the exemplary case according to Fig. In this embodiment, the angle is preferably 12°. Since the water cannot be drawn out of the pump in the event of a leak, and yet a safe operating condition is ensured, one embodiment can be described as a self-priming vacuum pump.

[0025] Specifically, the invention relates to a vacuum pump, in particular a self-priming vacuum pump, as a component of a vacuum wastewater system for emptying and flushing toilets, urinals, and the like, with a collecting inlet line connected to an inlet in a housing of the vacuum pump and closed within the housing by a check valve when the vacuum pump is not in operation, optionally with a cutting device arranged axially and which comminutes solid materials in the wastewater, further comprising an axially arranged screw spindle which, when rotated, forms a water ring necessary for generating the vacuum and draws in the wastewater by means of negative pressure, further comprising an outlet and a drive motor, characterized in that the vacuum pump comprising a suction nozzle (4) arranged in the inlet (3b), which is configured such that the suction nozzle (4) is always in fluidic contact with an outer diameter (4b) of a water reserve (5); and the non-return valve (6) is arranged at an angle between 1° and 90° relative to a vertical axis of the inlet-suction port transition (7) and completely covers the suction port (4), wherein the suction nozzle (4) is further arranged such that in the event of a leak in the non-return valve (6) none of its inner diameters (4a) can come into fluidic contact with a level of the water reserve (5), and the suction nozzle (4) is arranged at a height to the water level that ensures a sufficient water reserve (5) for suction under all operating conditions.

[0026] The invention therefore relates in particular to a self-priming vacuum pump, such as those used for emptying and flushing toilets or urinals and the like in a vacuum wastewater system of ships, aircraft, and trains. The wastewater containing feces is drawn in by the vacuum pump via collection lines, the solid components of the wastewater are macerated in the vacuum pump, and then the entire wastewater is conveyed to a collection tank. The vacuum pumps usually operate on the screw spindle principle.

[0027] The in Fig. The vacuum pump (1) shown is divided into the parts essential for the invention: - a housing (2) with a, as in Fig. 1 shown, top-mounted inlet (3) for wastewater from one or more toilets etc., - the, as in Fig.1 shown, suction nozzle insert (4) inserted from above into the inlet (3) with an inner diameter (4a) which is not in fluid contact with the water reservoir (5), and an outer diameter (4b) which is in fluid contact with the water reservoir (5); - a non-return valve (6) attached to the suction nozzle insert (4), which is able to completely close the suction nozzle insert.

[0028] Furthermore, the vacuum pump is designed so that it can be integrated into existing wastewater systems without major modifications. Reference symbol list 1 vacuum pump 2 cases 3a Collective inlet 3b Enema 4 suction nozzle inserts 4a an inner diameter of the suction nozzle insert that is not in fluidic contact with the water reservoir 4b an outer diameter of the suction nozzle insert that is in fluidic contact with the water reserve 5 Water reserve with stylized arrows pointing from top to bottom to represent gravity and directions “up” (no arrowhead) and “down” (with arrowhead). 6 Check valve 7 Inlet-suction nozzle transition QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 0 454 794 B2 [0012, 0016] WO 2012 / 115 521 A1 [0012, 0016] DE 10 2018 001215 A1

[0018]

Claims

[1] Vacuum pump (1), in particular a self-priming vacuum pump (1), as part of a vacuum wastewater system for emptying and flushing toilets, urinals and the like, comprising a collecting inlet line (3a) which is connected to an inlet (3b) in a housing (2) of the vacuum pump (1) and which is closed inside the housing (2) by a check valve (6) when the vacuum pump (1) is not in operation, optionally comprising a cutting device which is axially arranged and which comminutes solids in the wastewater, further comprising an axially arranged screw spindle which, when rotated, forms a water ring necessary for generating the vacuum and draws in the wastewater by means of vacuum, further comprising an outlet and a drive motor, characterized by , that the vacuum pump (1) ▪ comprises a suction nozzle (4) arranged in the inlet (3b), which is configured such that the suction nozzle (4) is always in fluidic contact with an outer diameter (4b) of a water reserve (5); ▪ and the check valve (6) is arranged at an angle between 1° and 90° relative to a vertical axis of the inlet-suction port transition (7) and fully seals the suction port (4), wherein the suction port (4) is further arranged such that, in the event of a leak in the check valve (6), none of its inner diameters (4a) can come into fluidic contact with a level of the water reserve (5), and the suction nozzle (4) is arranged at a height to the water level that ensures a sufficient water reserve (5) for suction under all operating conditions. [2] Vacuum pump (1) according to claim 1, wherein the suction nozzle (4) is further arranged rotatably, preferably rotatable by 180°, more preferably rotatable by 270°, and even more preferably rotatable by 360°. [3] Vacuum pump (1) according to claim 1 or 2, wherein the check valve (4) is selected from a material from the group consisting of nitrile rubber (NBR), Viton, and rubber. [4] Vacuum pump (1) according to one of claims 1 to 3, wherein the check valve (4) is fastened with a suitable preload via a lifting nut, a sleeve, a spacer bushing and / or a screw. [5] Vacuum pump (1) according to claim 4, wherein the spacer sleeve has a height which is equal to or substantially equal to the thickness of the material of the check valve. [6] Vacuum pump (1) according to any one of claims 1 to 5, wherein the vacuum pump (1) is a spiral wheel pump.

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