DE20016016U1 - Control cover for a liquid ring pump and pump provided with such a control cover - Google Patents

Description

Control cover for a liquid ring pump and pump provided with such a control cover

The present invention relates to a control cover for a liquid ring pump and a pump provided with such a control cover.

Liquid ring pumps or compressors have been around for a long time and are used in a wide variety of engineering processes. Examples include use in plants for plastics or pharmaceutical production, beverage bottling and paper production.

Such pumps or compressors work according to the displacement principle, whereby - in the most common design - a motor-driven impeller equipped with blades is arranged eccentrically in a mostly cylindrical working chamber housing, which has an interior with an essentially circular cross-section. In the working chamber housing there is an operating fluid, for example water, which is set in rotation by the rotation of the impeller and forms a liquid ring. Neighbouring blades of the impeller define chambers with the liquid ring and the hub of the impeller, which, due to the eccentric bearing of the impeller, have a volume that depends on the angular position of the chamber, whereby the liquid ring penetrates more or less deeply into the chamber and acts like a displacement piston.

The pump's operating fluid essentially has three functions. Firstly, as explained above, it acts as the piston of the displacement pump. It also seals the individual chambers of the impeller against each other, so that the fluid to be pumped can be pumped without oil. Due to its design, when a liquid ring pump is in operation, a certain amount of operating fluid from the liquid ring is always pumped along with the fluid to be pumped. This constant pumping of the operating fluid can be used to dissipate the compression heat generated when the pump is running. Operating fluid must therefore be continuously supplied so that the liquid ring is kept at a constant level. In order to keep the consumption of operating fluid as low as possible, the pumped operating fluid can be recovered in a downstream liquid separator, cooled if necessary and returned to the suction area of the working chamber.

Speck pumps, Roth

M/41501

In the axial direction, the working space is limited on at least one side of the impeller by a control disk in which openings, so-called suction and pressure openings, are cut out, through which the chambers defined by the impeller blades communicate with the inlet and outlet of the pump. The suction opening is located in the angular range in which an increase in the chamber volume takes place, while the pressure opening is arranged in the angular range with a decreasing chamber volume.

Liquid ring pumps are particularly suitable for pumping gases and vapors.

However, liquid flows can also be pumped to a certain extent. Due to this basic design, the liquid ring pump is extremely wear-resistant, has a high level of operational reliability and generates very little inherent noise. Liquid ring pumps of this type can be designed as so-called base plate pumps, in which the working chamber housing is covered on one or both sides by a pump housing with a control disk. Another widely used variant is the so-called block pump, in which the working chamber housing is flanged directly to the drive motor. The motor shaft is guided into the working chamber by a mechanical seal, where the impeller is connected to the free end of the shaft in a rotationally fixed manner. On the side of the impeller opposite the drive motor, the block pump has a pump housing.

The pump housings are equipped with suction and/or pressure ports for supplying or discharging the fluid to be pumped, as well as with connections for supplying (and, if necessary, draining) operating fluid.

The control disc is usually arranged between the pump housing and the working chamber with the rotating impeller. In between, a suction chamber is defined, which connects the suction port with the suction opening of the control disc, and a pressure chamber, which connects the pressure port with the pressure opening of the control disc. Conventionally, the pump housing, the control disc and the working chamber housing are designed as individual parts, which are connected to one another by screw connections, for example. The manufacturing and assembly effort involved in building such a pump is correspondingly high. In addition, in conventional pumps, in order to maintain a high level of efficiency at different pressure conditions, it is necessary to design the pressure openings of the control disc variably. For example, additional valve-operated

Speck pumps, Roth

M/41501

Pressure openings are known that open at a certain pressure difference and increase the effective area of the pressure opening. The disadvantage of such a solution is that the individual pressure openings are still comparatively small and consequently correspondingly high throttling losses occur.
5

The present invention is therefore based on the technical problem of providing a liquid ring pump which is simpler and more cost-effective to manufacture and which ensures a high degree of efficiency under different operating conditions.

This technical problem is solved according to the invention by forming a pump housing designed as a housing cover and the control disk as a one-piece component. For the sake of simplicity, when we refer to housing covers below, this should be understood to mean both housing covers for block pumps and housing covers for base plate pumps, the latter having a passage for the drive or pump shaft. The one-piece unit consisting of the housing cover with suction and/or pressure connection and control disk is referred to below as the control cover.

The subject of the present invention is therefore first of all a control cover for a liquid ring pump with a housing cover which has a suction nozzle and/or a pressure nozzle, and a control disk which has at least one suction opening and/or at least one pressure opening, wherein according to the invention it is provided that the housing cover and the control disk are designed as a one-piece component. Conventionally, the housing cover with the suction and/or pressure nozzles is already a one-piece component, so that according to the invention the complete unit of the housing cover with suction and/or pressure nozzles and the control disk form a one-piece component. Pressure and suction nozzles, as well as the associated pressure and suction openings, can be provided in the same control cover on one side of the impeller or in two control covers located on opposite sides of the impeller.

The control cover according to the invention is simply flanged onto the working chamber housing of the pump after the impeller has been attached to the drive shaft, so that the assembly effort is reduced compared to conventional pumps. Due to the one-piece design of the housing cover and control disk, fewer seals are required and the operational reliability of the pump, as well as its efficiency, are improved compared to conventional liquid ring pumps.

Speck pumps, Roth

M/41501

The one-piece control cover can be made of all materials conventionally used for pump housings of liquid ring pumps. The control cover according to the invention is particularly preferably designed as a one-piece cast part. After casting, only the area of the control cover that serves as the control disk needs to be machined flat, so that manufacturing effort and costs are also reduced compared to conventional liquid ring pumps.

The control disk is particularly preferably an integral component of the housing cover. For example, the control disk can be designed as a substantially planar inner surface of the housing cover in which the pressure and/or suction openings are recessed.

According to a preferred embodiment of the control cover according to the invention, the inner surface serving as a control disk has a recess in an area that is located near the drive shaft of the liquid ring pump during operation, into which a channel for supplying operating fluid opens. Operating fluid can be fed into the working chamber via this channel during operation in order to compensate for ongoing losses of operating fluid. A groove is preferably cut out in the inner surface, which, starting from the recess, leads into the suction area of the control disk. This ensures that in the area in which the channel for supplying operating fluid opens into the inner surface, a negative pressure prevails during operation, which sucks the operating fluid into the working chamber.

According to a particularly preferred embodiment of the control cover according to the invention, the suction port via the suction opening and/or the pressure port via the pressure opening open directly into the inner surface of the control cover, which acts as a control disk. In contrast to conventional liquid ring pumps, there are therefore no longer any suction and pressure chambers between the suction and pressure ports on the one hand and the suction or pressure opening of the control disk on the other. A pump provided with the control cover according to the invention is therefore shorter and the material expenditure is reduced. Since the suction and pressure chambers are missing in the control cover according to the invention, no corresponding partition walls are required. The control cover according to the invention is therefore easy to produce using casting technology. Since the

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Speck pumps, Roth

M/41501

Since the suction and pressure ports pass directly into the corresponding openings in the control disc, no lost cores are created during casting.

Advantageously, the suction and pressure ports open at an angle into the inner surface of the control cover, which serves as a control disk, which improves protection against cavitation. Advantageously, the suction and pressure ports open into the inner surface at an angle of 20° to 70°, preferably 25° to 45° and particularly preferably at an angle of about 30°.

Surprisingly, it is found that a liquid ring pump provided with the control cover according to the invention can be realized without variable pressure openings and still guarantees a high level of efficiency under different operating conditions. Therefore, in a particularly preferred variant of the control cover according to the invention, variable pressure openings are completely dispensed with, so that only a single pressure opening is provided in the control disk. 15

The control cover according to the invention can not only be used in new liquid ring pumps, but it can also be manufactured as a replacement part for existing liquid ring pumps. For this purpose, in conventional pumps, only the housing cover with pressure and/or suction nozzle, the pump housing with pressure and/or suction chamber and the control disk are removed and replaced with a control cover according to the invention, which is dimensioned in such a way that it can be attached, preferably screwed, to the existing working chamber housing.

According to another embodiment, a substantially cylindrical working chamber housing is also provided on the control cover, which is integral with the control cover. In this variant, the control cover and the working chamber housing can be manufactured in the form of a single cast part.

The present invention also relates to a liquid ring pump with a working chamber housing, at least one impeller rotatably arranged in the working chamber housing, which impeller can be driven by a motor, wherein the pump is characterized in that it has a control cover as defined above.

The working chamber housing usually has a cylindrical general shape and has a connecting flange to which the control cover according to the invention is attached

Speck pumps, Roth

M/41501

The control cover and the working chamber housing can also form a single-piece casting.

According to a first variant of the liquid ring pump according to the invention, the control cover is designed as a housing cover of a block pump, while according to a second variant, the control cover is designed as a pump housing of a base plate pump. In the latter case, the control cover has a passage for the drive shaft of the pump.

The present invention is explained in more detail below with reference to an embodiment shown in the accompanying drawings.

In the drawings

Figure 1 is a schematic axial longitudinal section of a

Liquid ring pump provided with the control cover according to the invention;
Figure 2 is a plan view of the outer face of the inventive

control cover;
Figure 3 is a plan view of the inner surface of the control disc

Control cover of Figure 2;

Figure 4 is a section along the line IV-IV in Figure 2;

Figure 5 is a section along the line V-V in Figure 2;

Figure 6 is a section along the line VI-VI of Figure 2; and

Figure 7 is a top view of the control cover of Figure 2.

Figure 1 shows a preferred embodiment of a liquid ring pump 10 according to the invention, which in this case is designed as a block pump. The pump 10 has a substantially cylindrical working chamber housing 11, which (perpendicular to the plane of the drawing in Figure 1) has a substantially circular cross-section. An impeller 12 is arranged eccentrically in the working chamber housing 11. The impeller 12 has substantially radially oriented blades 13 and is coupled in a rotationally fixed manner to the free end of a drive shaft 14 of a motor 15. The drive shaft 14 is guided by a mechanical seal 16 into the working chamber housing 11, which in the example shown is designed as one piece with the mechanical seal housing. On the motor

Speck Pumps, Roth j "*, . : !·..:.* :: : M/41501

opposite side of the impeller 12, the working chamber housing 11 is closed by a preferred embodiment of the control cover 20 according to the invention. The control cover is flanged to the working chamber housing 11 via a sealing ring 17 and is detachably fastened via screw connections 18.

The control cover 20 is a one-piece casting which comprises the housing cover 21 and the control disk 25 and is explained in more detail below with reference to Figures 2 to 7.

Figure 2 shows a top view of the outer face 22 of the housing cover 21 of the control cover 20, based on the installed state. In the example shown, the housing cover 21 has a suction port 23 for sucking in the medium to be pumped, for example air, and a pressure port 24 for discharging the medium compressed in the pump 10. The inner surface 26 of the housing cover 21 shown in the top view in Figure 3 is flat and serves as the control disk 25 of the liquid ring pump 10. For this purpose, a suction opening 27 is recessed in the inner surface 26, into which the suction port 23 opens. Furthermore, a pressure opening is recessed in the inner surface 26, into which the pressure port 24 opens. In its central area, the inner surface 26 has a recess 29 into which a channel 30 opens, via which operating fluid can be sucked into the working chamber of the pump. In order to ensure a negative pressure in the area of the recess 29 during operation, the inner surface 26 has a groove

31, which leads from the recess 29 into the suction area of the pump. The channel 30 passes through the housing cover 21 and has a connection piece on the front side 22

32, to which, for example, a connecting line from a (not shown) liquid separator and/or heat exchanger for cooling the returned operating liquid can be connected. In the lower area, the housing cover has a closable opening 33 for draining the operating liquid from the working chamber housing 11 (see also Figure 1). Bores 34 are distributed on the outer circumference of the control cover 20, which enable the control cover 20 to be attached to the working chamber housing 11 by means of screw connections 18, as shown in more detail in Figure 1.

The orientation of the suction and pressure nozzles 23, 24, which point upwards in the example shown, can be chosen arbitrarily and adapted to the respective requirements during manufacture.

Speck-Pumpen, Roth j *". . &iacgr; *·..: . : ;: : M/41501

Figure 4 shows a section along the line IV-IV of Figure 2. It can be seen that the suction nozzle 23 opens obliquely into the suction opening 27 cut out in the inner surface 26 of the control disk 25. The opening angle α is approximately 30° in the example shown. 5

Figure 5 is a section along the line V-V of Figure 2 and shows that the pressure nozzle 24 also opens into the pressure opening 28 recessed in the inner surface 26 at an angle β of approximately 30°.

Figure 6 shows a corresponding section along the line VI-VI of Figure 2. In particular, one can see the channel 30 which opens into the recess 29 of the inner surface 26 and is used to supply operating fluid.

Finally, Figure 7 shows a plan view of the control cover according to the invention, whereby in particular the short, space- and material-saving design can be seen, which results from the elimination of pressure and suction chambers.

Claims (13)

1. Control cover for a liquid ring pump with,
a housing cover ( 21 ) having a suction port ( 23 ) and/or a pressure port ( 24 ), and
a control disk ( 25 ) which is designed as a substantially planar inner surface ( 26 ) of the housing cover ( 21 ) and has at least one suction opening ( 27 ) and/or at least one pressure opening ( 28 ), wherein the housing cover ( 21 ) and the control disk ( 25 ) are designed as a one-piece component ( 20 ), characterized in that the suction nozzle ( 23 ) opens directly into the inner surface (26) via the suction opening ( 27 ) and/or the pressure nozzle ( 24 ) opens directly into the inner surface ( 26 ) via the pressure opening ( 28 ). 2. Control cover according to claim 1, characterized in that the suction and/or pressure nozzle ( 23 , 24 ) open obliquely into the inner surface ( 26 ). 3. Control cover according to claim 2, characterized in that the suction and pressure nozzles ( 23 , 24 ) open into the inner surface ( 26 ) at an angle of 20° to 70°, preferably 25° to 45° and particularly preferably about 30°. 4. Control cover according to one of claims 1 to 3, characterized in that the one-piece component ( 20 ) is a cast part. 5. Control cover according to one of claims 1 to 4, characterized in that the inner surface ( 26 ) has, in a region which is located in the vicinity of a drive shaft of the liquid ring pump during operation, a recess ( 29 ) into which a channel ( 30 ) for supplying operating fluid opens. 6. Control cover according to claim 4, characterized in that a groove ( 31 ) is recessed in the inner surface ( 26 ), which groove leads from the recess ( 29 ) into a suction region of the control disk ( 25 ). 7. Control cover according to one of claims 1 to 6, characterized in that exactly one pressure opening ( 28 ) is provided in the inner surface ( 26 ). 8. Control cover according to one of claims 1 to 7, characterized in that the one-piece control cover ( 20 ) further comprises a cylindrical working chamber housing ( 11 ). 9. Liquid ring pump ( 10 ) with
a working chamber housing ( 11 ),
at least one impeller ( 12 ) which is rotatably arranged in the working chamber housing and which can be driven by a motor ( 15 ), characterized in that the pump ( 10 ) has a control cover ( 20 ) according to one of claims 1 to 8. 10. Liquid ring pump according to claim 9, characterized in that the control cover ( 20 ) is flanged to the cylindrical working chamber housing ( 11 ). 11. Liquid ring pump according to claim 10, characterized in that the control cover ( 20 ) is integral with the cylindrical working chamber housing ( 11 ). 12. Liquid ring pump according to one of claims 9 to 11, characterized in that the control cover ( 20 ) is designed as a housing cover ( 21 ) of a block pump. 13. Liquid ring pump according to one of claims 9 to 11, characterized in that the control cover ( 20 ) is designed as a pump housing of a base plate pump.