Liquid ring pump

Abstract

A liquid-ring pump comprises a housing defining a pump chamber 32 and a rotor 44 in the pump chamber to generate a liquid ring. The housing comprises an inlet 16 and an outlet and the pump chamber com

Description

The present invention relates to a liquid ring pump in particular a liquid ring vacuum pump ora liquid ring compressor pump. Further, the present invention relates to a method for fabrication of such a liquid ring pump. With the advent of electric trucks the need for smaller and lighter pumps as auxiliary pumps emerges which can be included into the electric trucks being small and having a reduced power consumption. One example of a suitable pump is a liquid ring pump. A liquid ring pump comprises a housing defining a pump chamber. The pump chamber is filled, i.e. partially filled, with a liquid such as water. Further, a rotor comprising a veined impeller is located eccentrically within the pump chamber. Due to centrifugal force created by rotation of the veined impeller onto the liquid, a cylindrical ring is formed inside the pump chamber. The liquid ring creates a series of seals in the space between the impeller veins and the pump chamber wall forming compression chambers. Due to the eccentricity between the rotor axis of rotation and the geometry of the pump chamber, a cyclic variation of the volume enclosed by the veins and the ring is created, providing compression and conveyance of a gaseous medium. Such a liquid ring pump is for example known from DE 20005916 UI. In common liquid ring pumps, the housing comprises a central element having approximately the same length in the axial direction than the impeller of the rotor. Both axial ends of the center element of the housing are closed by respective covers or lids supporting bearing journals of the rotor, respectively. Thus, the pump chamber is defined by or enclosed by the center element of the housing and two lids. Since the center element of the housing is complex in shape, in the case that different liquid ring pumps with different pump capacity are required, for each of these different liquid ring pumps an individual center element must be formed. This requires adaption of the casting mold for the respective part which increases complexity of liquid ring pump fabrication. It is an object of the present invention to provide a liquid ring pump having a modular design and providing an increased flexibility. The problem is solved by a liquid ring pump according to claim 1 as well as a fabrication for such a liquid ring pump according to claim 12. The liquid ring pump according to the present invention may be built as liquid ring vacuum pump or liquid ring compressor. The liquid ring pump comprises a housing defining a pump chamber. The rotor is arranged in the pump chamber to generate a water or liquid ring. In particular, the rotor comprises a veined impeller arranged eccentrically within the pump chamber. Upon rotation of the veined impeller, by the liquid ring a seal between the veins and the pump chamber is created providing a plurality of compression chambers in the spaces between the impeller veins. Further, the housing comprises an inlet and an outlet. The inlet of the housing is connected to at least one inlet of the pump chamber by a first channel, wherein the outlet of the housing is connected to at least one outlet of the pump chamber by a second channel. Thus, upon rotation of the rotor a gaseous medium is conveyed from the inlet of the housing via the first channel to the pump chamber and towards the outlet of the housing via the second channel. Therein, according to the present invention the housing comprises a first housing part and a second housing part which, when mounted together, defining the pump chamber. Thus, by the first housing part and the second housing part the pump chamber is completely enclosed. Thus, compared to the prior art where the pump chamber is defined and enclosed by a center housing element and two opposing lids or covers, the number of necessary parts is reduced, since only the first housing part and the second housing part are necessary to form the pump chamber. Thus, complexity of the assembly is reduced. Preferably, the first channel and / or the second channel are integrated into the first housing part. Alternatively or additionally, the first channel and / or the second channel are integrated into the second housing part. Thus, the first channel and / or the second channel are directly incorporated into the housing. No external piping is necessary and a compact liquid ring pump is provided. Preferably, the housing is built by exactly the first housing part and the second housing part. Thus, by assembly of the first housing part and the second housing part substantially the overall shape is provided and the number of necessary housing parts can be reduced. Preferably, the first housing parts and the second housing parts are substantially identical. Therein, "substantially identical" refers to a structural correspondence of the first housing part and the second housing part. This in particular relates to the elements of the first housing part and the second housing part providing the pump chamber. Thus, the pump chamber is combinedly provided by the first housing part and the second housing part, wherein the part of the pump chamber provided by the first housing part is identically to the part of the vacuum chamber provided by the second housing part. In particular, the axial length of the part of the pump chamber provided by the first housing part and the second housing part is identical. If the first channel and / or the second channels are integrated into the first housing part and the second housing part, also the structure of the first channel and the second channel in the first housing part and the second housing part may be identical. In particular, substantially identical refers to the fact that the first housing part and the second housing part may be made from the same casting element. Thereby, complexity of the housing and the fabrication method of the housing is reduced and in particular reducing the number of casting elements for the liquid ring pump. Due to subsequent machine of the first housing part and the second housing part minor differences may appear. In particular, one of the bearing journals may extend through the axial end face of either the first housing part or the second housing part as a shaft in order to serve as driving shaft for the rotor without deviating from the substantially identical shape of the first housing part and the housing part. Alternatively, the first housing part and the second housing part are different, wherein the second housing part is substantially disk shaped, i. e. provided as a substantially disk-shaped lid. Thus, by the lid of the second housing part the pump chamber formed in the first housing part is axially closed. In particular, in the lid a bearing is provided for rotatably supporting the rotor. Preferably, the pump chamber is provided within the first housing part alone. In particular, if the second housing part is provided by a disk-shaped lid, the pump chamber is completely formed within the first housing part and only axially closed by the lid of the second housing part. Alternatively, the pump chamber is provided within the first housing part and the second housing part combinedly. In particular, if the first housing part and the second housing part are substantially identical, the pump chamber is formed together by the first housing part and the second housing part. In particular and as mentioned before, the axial length of the first housing part and the second housing part are identical and in particular the pump chamber is divided into halves by the first housing part and the second housing part. Thus, the part of the pump chamber formed by the first housing part receives a first half of the veined impeller, wherein the second half of the veined impeller is situated and received in the part of the pump chamber formed by the second housing part. Preferably, in a first configuration of the liquid ring pump, the first housing part and the second housing part are different and in a second configuration of the liquid ring pump, the first housing part and the second housing part are substantially identically. Therein, the first housing part of the first configuration corresponds to the first housing part and the second housing part of the second configuration. Thus, by providing the first housing part different configurations of the liquid ring pump can be provided. In particular, by the first configuration and the second configuration pump capacity of the liquid ring pump can be adapted without the need of additional casting elements. Thus, in the first configuration the liquid pump may have a smaller pump chamber as in the second configuration. In particular, the pump chamber of the second configuration is approximately double in size as the pump chamber of the first configuration. Consequently, two different liquid ring pumps having two different pump capacities can be provided with only two different casting elements, i. e. the first housing part, the first housing part of the first configuration and second housing part of the second configuration as one casting element as well as the second housing part of the first configuration as second casting element. Thus, flexibility of the liquid ring pump is enhanced without increase of complexity of the fabrication method. In particular, the number of elements of the housing in the first configuration or the second configuration does not increase. Preferably, the axial rotor length and / or the axial length of the pump chamber in the second configuration are twice as long as in the first configuration. Hence, by comparison between the first configuration and the second configuration, the volume of the pump chamber as well as the axial length of the rotor is doubled. Preferably, the pump chamber comprises two inlets and two outlets at opposite axial ends of the pump chamber. In particular, in the second configuration the pump chamber comprises two inlets and two outlets at opposite axial ends of the pump chamber, respectively. The two inlets of the pump chamber are connected by the first channel to the inlet of the housing, wherein the two outlets of the pump chamber are connected by the second channel to the outlet of the housing. Hence, due to the two inlets and two outlets of the pump chamber, pump performance is increase. Preferably, the housing comprises an upper end and an opposite lower end. Therein, the upper end and the lower end may be defined by the arrangement of the liquid inlet and liquid outlet and / or the eccentricity of the rotor within the pump chamber. Thus, liquid ring pumps have a predefined default orientation defining the upper end and the opposite lower end of the housing. Therein, the upper end and lower end comprise fixing means in order to be able to mount the liquid ring pump in an upstanding configuration for example by the fixing means of the lower end or to mount the liquid ring pump hanging for example by the fixing means at the upper end. Thus, increased flexibility in mounting the liquid ring pump is provided. Preferably, the first housing part as well as the second housing part comprises fixing means at the upper end and the opposite lower end respectively. Thus, by the combination of the first housing part and the second housing part, fixing means are provided in order to securely mount the liquid ring pump into the respective application, i. e. a truck. Preferably, the rotor comprises a veined impeller and bearing journals at both ends of the veined impeller. Therein, the bearing journals and the veined impeller are separate parts. Thereby, the veined impeller can be fabricated from a casting element having a reduced axial length. If the rotor is machined from a workpiece, also the workpiece can be reduced in size. In particular, in the sections of the bearing journal a lot of material of the workpiece must be removed. Due to forming the veined impeller and the bearing journals as separate parts, the veined impeller and the bearing journals can be fabricated from different workpieces and mounted together subsequently. Thus, machining time is reduced and costs as well. In particular, the bearing journals and the veined impeller are mounted together by bolts. This also increases flexibility in case of maintenance and replacement of the veined impeller or the bearing journal and avoiding the necessity of replacement of the whole rotor in case of damage of only a specific part thereof. In an aspect of the present invention a method for fabricating a liquid ring pump as described before is provided. The method includes: Providing a first casting part or element for the first housing part and providing a second casting part or element for the second housing part and assemble the first housing part with the second housing part. Preferably, between assembly of the first housing part with the second housing part, machining of the first casting part and / or the second casting part may be performed in order to fabricate the first housing part and the housing part. Preferably, the first casting part and the second casting part are identical. This in particular relates to the second configuration of the liquid ring pump. Alternatively, the first casting part and the second casting part are different. This in particular relates to the first configuration of the liquid ring pump. In the following the present invention is described in more detail with reference to the accompanying figures. The figures show: Figure 1 a liquid ring pump according to the present invention in a first configuration, Figure 2 a liquid ring pump according to the present invention in a second configuration, Figure 3 a sectional view of the liquid ring pump of figure 1 and Figure 4 a sectional view of the liquid ring pump according to fig ure 2. A liquid ring pump 10 in a first configuration as shown in Figures 1 and 3 comprises a first housing part 12 and a second housing part 14 mounted together by bolts 24. The first housing part 12 comprises an inlet 16 and an outlet 18. Therein, the first housing part 12 and the second housing part 14 are shaped differently and in particular made from different casting elements. By the first housing part 12 and the second housing part 14 a pump chamber 32 is defined or fully enclosed. Therein, the pump chamber 32 is formed or provided completely within the first housing part 12 and only the axial end of the pump chamber 32 is enclosed by the second housing part 14 substantially shaped as a lid. In the pump chamber 32 a rotor 44 is disposed comprising a veined impeller 34 arranged in the pump chamber 32. To the respective axial ends of the veined impeller 34 the bearing journals 26 attached by bolts 46. Thus, bearing journals 26 and veined impeller 34 are built as separate parts, which can be separated. The bearing journals 26 are supported by a first bearing 40 in the second housing part 14 and a second bearing 42 in the first housing part 12. One bearing journal 26 extends in the axial direction through the axial end of the first housing part 12 providing a driving shaft in order to rotate the rotor 44 and the veined impeller 34 in the pump chamber 32. Therein, the pump chamber 32 comprises in the first configuration shown in Figures 1 and 3, one inlet and one outlet (not visible) connected by integrated channels 36 to the respective inlet 16 or outlet 18 of the first housing part 12. Thus, a gaseous medium is conveyed from the inlet 16 via a first channel 36 to the inlet of the pump chamber 32 and com-pressed / conveyed via a second channel 36 towards the outlet 18 of the housing 12. Lubrication channels 38 may be arranged at the radial end of the pump chamber 32. Hence, by the centrifugal force acting on the liquid in the pump chamber 32, the liquid is pumped into the area of the bearing journals 26 via the lubrication channels 38 lubricating shaft seals sealing the pump chamber 32 against the shaft of the rotor 44. As indicated in the Figures, the housing of the liquid ring pump 10 comprises fixing means 20 at its upper end and as well fixing means 22 at its lower end. Thus, the liquid ring pump 10 can be mounted to the respective application in an upstanding configuration or a hanging configuration. Therein, fixing means 20, 22 are provided combinedly by the first housing part 12 and the second housing part 14 (or second housing part 12' in the second configuration as shown in Figures 2 and 49. Referring to the liquid ring pump 10' in a second configuration shown in Figures 2 and 4. Therein, same or similar elements are indicated by identical reference signs. In comparison with the liquid ring pump 10 of the first configuration as shown in Figures 1 and 3, the liquid ring pump 10' of Figures 2 and 4 comprises a first housing part 12 and a second housing part 12', which is substantially identical to the first housing part 12. The first housing part 12 and the second housing part 12' are connected by bolts 28. The pump chamber 32 of the liquid ring pump 10' in the second configuration can be separated or is split into two parts provided by the first housing part 12 and the second housing part 12' along a separation line 43. Therein, the first housing part 12 and the second housing part 12' are made from the same casting element. In particular, the first housing part 12 and the second housing part 12' are identical with respect to the arrangement of the channel 36 in the case that the channels 36 are integrated into the housing. Further, the first housing part 12 and the second housing part 12' are identical with respect to the shape of the pump chamber 32, which is provided combinedly by the first housing part 12 and the second housing part 12'. In comparison with the embodiment of Figures 1 and 3 the first housing parts 12 of the two configurations are identical and the second housing part 14 of the configuration of Figures 1 and 3 is replaced by a second housing part 12' being identical to the first housing part 12 of both configurations. Hence, by two different casting elements, two different geometries of a liquid ring pump can be provided with adapted pump performance. In particular, the veined impeller 34 of the configuration of Figures 1 and 3 is half as long as the veined impeller 34 of the second configuration as shown in figures 2 and 4. Similar also the axial length of the pump chamber 32 is doubled in the second configuration of Figures 2 and 4 compared to the axial length of the pump chamber 32 of the first configuration of Figures 1 and 3. As shown in figure 2 and also indicated in Figure 4, inlet 16 is provided at the first housing part 12, wherein outlet 18 is provided at the second housing part 12'. Since the first housing part 12 of the configuration of Figures 1 and 3 is reused also for the liquid ring pump in the second configuration as shown in Figures 2 and 3, a cover 30 may enclose the second opening of the outlet channel 36 to have a single outlet 18. Similar for the inlet 16 connected to the inlet channel 36, a second opening of the second housing part 12' is covered by a cover 30. Thus, by the present invention a modular constructed liquid ring pump is proved which can be easily adapted in its pump performance without increase of necessary parts or the necessary casting elements, thereby reducing the costs for manufacturing and assembly. Reference List: 10 liquid ring pump 10' liquid ring pump 12 first housing part 12' second housing part 14 second housing part 16 inlet 18 outlet 20 fixing means 22 fixing means 24 bolts 26 bearing journals 28 bolts 30 cover 32 pump chamber 34 veined impeller 36 channel 38 lubrication channel 40 first bearing 42 second bearing 43 separation line 44 rotor 46 bolts

Claims

1.

1. Liquid-ring pump comprising:a housing defining a pump chamber,a rotor arranged in the pump chamber to generate a liquid ring,wherein the housing comprises an inlet and an outlet and the pump chamber comprises at least one inlet and at least one outlet, wherein the inlet of the housing is connected to the at least one inlet of the pump chamber by a first channel and the outlet of the housing is connected to the at least one outlet of the pump chamber by a second channel,wherein the housing comprises a first housing part and a second housing part defining the pump chamber.

2. Liquid-ring pump according to claim 1, wherein the first channel and / or the second channel are integrated into the fist housing part and / or the second housing part.

3. Liquid-ring pump according to claim 1 or 2, wherein the housing is built by exactly the first housing part and the second housing part.

4. Liquid-ring pump according to any of claims 1 to 3, wherein the first housing part and the second housing part are substantially identical and in particular made from the same casting element.

5. Liquid-ring pump according to any of claims 1 to 3, wherein the first housing part and the second housing part are different, wherein the second housing part is a substantially disk shaped lid.

6. Liquid-ring pump according to any of claims 1 to 5, wherein the pumpchamber is provided within the first housing part atone or within the first housing part and the second housing part combinedly.

7. Liquid-ring pump according to any of claims 1 to 6, wherein in a first configuration of the liquid-ring pump the first housing part and the second housing part are different and in a second configuration of the liquid-ring pump, the first housing part and the second housing part are substantially identically, wherein the first housing part of the first configuration corresponds to the first housing part and second housing part of the second configuration.

8. Liquid-ring pump according to claim 7, wherein the axial rotor length and / or the axial length of the pump chamber in the second configuration are twice as long as in the first configuration.

9. Liquid-ring pump according to any of claims 1 to 8, wherein the pump chamber preferably in the second configuration comprises two inlets and two outlets at opposite axial ends of the pump chamber, respectively, wherein the two inlets of the pump chamber are connected by the first channel to the inlet of the housing and the two outlets of the pump chamber are connected by the second channel to the outlet of the housing.

10. Liquid-ring pump according to any of claims 1 to 9, wherein the housing comprises an upper end and an opposite lower end, wherein at the upper end and the lower end fixing means are arranged to be able to mount the liquid-ring pump in an upstanding or hanging configuration.

11. Liquid-ring pump according to any of claims 1 to 10, wherein the rotor comprises a vaned impeller and bearing journals at both axial ends of thevaned impeller, wherein the bearing journals and the vaned impeller are separate parts preferably mounted together by bolts.

12. Method for fabricating a liquid-ring pump according to any of claims 1 to 11, including:Providing a first casting part for the first housing part andProviding a second casting part for the second housing part,Assemble the first housing part with the second housing part.

13. Method according to claim 12, wherein the first casting part and the second casting part are identically or differently.

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