US 3721508 A
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United States Patent Mugele H lMarch 20, 1973  Inventor: Kurt Mugele, Erlangen, Germany  Assignee: Siemens Aktiengesellschaft, Berlin and Munich, Germany  Filed: May 11, 1971 ] App]. No.: 142,340
Related U.S. Application Data  Continuationin-part of Ser. No. 871,868, Oct. 28,
 Foreign Application Priority Data April 26, i969 Germany ..P 19 21 430.3
 U.S. Cl ..4l7/68  Int. Cl ....F04c 19/00  Field of Search ..4l7/68, 69
 References Cited UNITED STATES PATENTS 2,306,988 12/1942 Adams ..4l7/69 3,366,3 l4 l/l968 Schriider ..4l7/68 Primary ExaminerCarlton R. Croyle Assistant Examiner-Richard E. Gluck Att0rneyCurt M. Avery et al.
 ABSTRACT Liquid-ring pump includes a vane rotor, a housing structure enclosing the rotor and having suction and compression ports communicating with intervane spaces of the rotor at respective suction and pressure localities thereof, pump outlet means, pressureresponsive control valves located outside the housing structure, pressure lines connecting the control valves, respectively, with the compression ports of the housing structure, the valves having respective outlets communicating with the pump outlet means, and shutoff valve means serially connected with each of the respective control valves.
9 Claims, 3 Drawing Figures LIQUID-RING PUMP WITH CONTROL VALVES This is a continuation-in-part of application Ser. No. 871,868, filed Oct. 28,1969, now abandoned.
My invention relates to liquid-ring pumps which comprise a vane rotor and a housing structure enclosing the rotor, the housing structure being provided with suction and compression ports to communicate with the intervane spaces of the rotor at respective suction and compression localities thereof. To utilize the pumping action of the centrifugated ring of liquid by periodically reducing and increasing the volume of the intervane spaces, the axis of the rotor extends in eccentric relation to that of the pump working space within the housing.
More specifically, the invention concerns liquid-ring pumps in which control or check valves are coordinated with the pressure ports of the housing structure so as to open in response to pressure.
Liquid-ring pumps constitute gas pumps or vacuum pumps of a particularly simple design. As the liquid, such as water, which partially fills the working space, is centrifugated by the rotor, it forms a rotating ring guided by the peripheral wall of the housing and two control plate members. The rotating water ring delimits cell spaces between the vanes of the rotor, and these cells increase and reduce their volume during each rotation of the rotor. The water-ring sectors thus pulsating in the cells thus act as water pistons. When the water recedes from an individual cell, the gas to be delivered is sucked through suction slots or ports of the control plate member into the cell then increasing its volume. During further rotation, the water-ring sector penetrates more deeply into the cell and compresses the gas contained therein, until the gas is forced out through pressure slots or ports of the control plate members.
As a rule, the usually crescent-shaped compression port 'is dimensioned for operation at the lowest economically attainable suction (negative) pressure. To prevent overcompression and vortex losses at larger suction pressures, it has become known to provide a few openings ahead of the pressure ports, relative to the direction opposed to that of the rotor rotation. Those openings that are located in the region of the delivery pressure, readily permit the gas to pass through, whereas the water located at the rear side of the control member closes all openings that are located in a region of lower pressure. This corresponds to a kind of water-valve effect since the flow resistance in the openings is considerably larger for water than for gas. When conditions of higher pressures are encountered, this water-valve effect no longer suffices. For that reason, the individual openings have been provided with pressure-responsive control valves, for example flap or ball valves operating as check valves. Those balls or flaps whose openings are already located in the region of the delivery pressure, readily permit the compressed gas to pass through, whereas all other balls or flaps are firmly pressed upon their valve seats under the effect of the higher pressure obtaining in the pressure outlet duct, and thus do not permit either gas or water to pass through.
Under aggravating operating conditions it may happen that the balls or flaps of the valves will become soiled, encrusted or worn so that the pump will gradually lose some of its pumping power. To take care of such cases, it is'known to construct the pumps in such a manner that the valves, upon unscrewing of valve covers, can be exchanged. This construction, though sufficient for most operating conditions, still leaves much to be desired because the exchange of individual valves consumes a considerable amount of labor and time and cannot be performed during operation of the pump. Furthermore, all valves communicate with a single pressure chamber so that a simultaneous delivery of gases at respectively different delivery pressures is impossible, the latter being desirable, for example, for various chemical processes.
It is an object of my invention to devise a liquid-ring pump which readily permits exchanging the control valves of the housing structure but which also affords a simultaneous gas delivery against respectively different pressures. Another, correlated object of the invention is to simultaneously afford increasing the efficiency of the pump when operating under partial load, i.e. at considerably less than the rated load.
To achieve these objects, and in accordance with my invention, 1 locate the control valves outside of the pump housing proper and connect them with the compression ports of the housing structure by respective pipelines; and I further provide these externally located control valves with series-connected shut-off valves.
According to a further feature of the invention, the housing structure forms a chamber axially adjacent each side of the rotor and has control plate members located axially between each side of the rotor and the adjacent chamber, the suction and compressions ports being provided in the control plate members.
According to another feature of my invention it is preferable to provide each of the line portions that contain a control valve and a shut-off valve with a parallel branch which also contains shut-off means, so that during exchanging of a control valve, the correlated port in the control plate member can remain effective at least partially.
According to still another feature of the invention, a simultaneous delivery of gas against different pressures is afforded by extending the control-valve line to a compression duct other than that of the pump housing.
For increasing the efficiency of the pump at partial load, at which the suction quantity is reduced while the rotating speed and the suction pressure remain unchanged, a further feature of the invention provides for a return line through which any excessively delivered quantity of gas is recycled through the lines that traverse the pump housing, back to the suction side of the pump.
The invention will be further explained with reference to embodiments illustrated by way of example on the accompanying drawing in which:
FIG. 1 shows a portion of a liquid-ring pump in section and in conjunction with a valve assembly according to the invention;
FIG. 2 is is a corresponding illustration of a modified embodiment; and
FIG. 3 is a view similar to that of FIG. 1 of still another embodiment of the invention.
In FIG. 1 there is shown a liquid-ring pump by a partial illustration of its vane rotor 1 and of the housing structure 7 which surrounds the rotor 1 and forms an interior space in which the rotor is eccentrically rotatable. Only a portion of the pump is shown schematically because pumps of this type are known as such, for example from US. Pat. Nos. 1,718,294 and 3,366,314.
The rotation of the rotor 1 flings the water, contained in the pump housing, against the peripheral wall of the housing structure and thus forms a rotating water ring which is guided by the housing structure 7 and by two control plates 6 which border the working space of the housing on both axial sides thereof. Between the vanes 2 of the rotor l the rotating water ring forms enclosed intervane spaces or cells 3 which periodically increase and thereafter decrease their respective volumes during each rotation of the rotor. As the water recedes from the enclosed volume of an individual cell, the gas to be delivered is sucked into the cell through nonillustrated suction slots.
Thereafter, the cell volume decreases as the water ring sector progressively enters more deeply into the cell, thus condensing the gas 4 until it is pushed through pressure ports 13 and 14, of which the port 14 leads into a lateral chamber 8 filled with water. This chamber is connected with the compression duct 18 of the pump. Some of the water is forced out of the working space together with the compressed gas. A water separator connected with the pump outlet but not illustrated on the drawing is used for separating the water from the gas. The pressure port 14 of the control plate has the shape of a crescent in the manner known as such and its area is preferably dimensioned for the smallest economically attainable suction pressure.
As mentioned, additional ports, namely the bores 13, are located ahead of the pressure port 14, seen in the running direction of the rotor 1. The bores 13 serve for adaptation to the instantaneous pressure conditions. In the known pumps, control valves, preferably check valves designed for example as flap or ball valves, are mounted directly on or near the control plates so as to be directly adjacent to the ports 13. v
In contrast thereto, in the pump according to the invention as shown in FIG. 1, control valves 11, designed as flap-type or ball-type check valves, are arranged outside of the pump housing structure 5, 7 proper, and are connected through respective pipelines 9 with the additional pressure ports 13 of the control plate members 6. The control valves 11 are inserted into the respective lines as exchangeable units, and each is connected in series with shut-off valves 10 and 12 located ahead of and behind the control valve 11 relative to the flow direction, of the medium. If only a single delivering pressure p is required, the line portions that contain the check valves 11 may open into a common manifold 16 which leads back to the plenum chamber 8 (FIG. I When the gas is to be delivered against different pressures, for example two pressures p p,, then one or more line portions following the valves 12 are connected through a manifold 16' with a separate compression duct 19 as shown in FIG. 2.
In FIG. 3 there is shown a liquid-ring pump with a control cone 6a located within a rotor la that is provided with a hollow hub. Structural details of this type of pump are known for example from U. S. Pat. No. 2,195,375. Additional pressure ports 13, shown in dotted lines, are provided ahead or upstream of the pressure port 14 of the control cone. The additional pressure ports 13 are connected through the pipelines 9 with the valves 11 in a manner similar to that for the embodiment shown in FIG. 1.
If, during operation, one of the control valves 11 becomes defective, it can be separated from the circulation by closing the appertaining shut-off valves 10 and 12, whereafter the control valve 11 can be removed. Simultaneously, a shut-off valve 15 correlated to the defective control valve 11 may be opened and the gas can then pass through a parallel path provided by means of a branch line 17. By connecting the parallel branches 17 through a shut-off and throttle valve 21 with the suction side of the pump, a partialload operation of particularly low losses is afforded, the suction quantity being then reduced while the rotating speed and suction pressure remain unchanged. By closing the valve 20 and partially opening the valve 21, the valve 15 in the shunt line 17 being open, any excessively delivered gas quantity can be recycled back to the suction side indicated by an arrow at 22, without the necessity of compressing this excessive gas quantity up to the higher delivery pressures p,, p',, etc. With respect to the gas quantity recycled in this manner, it is only necessary to provide the overpressure needed, above the suction pressure, for overcoming the line throttle losses.
For lucidity of illustration, the assembly is purposely shown in somewhat exploded fashion. In reality, a considerably more compact arrangement of the valves on or at the shield 5 of the pump housing structure is preferable.
It will be noted that the invention requires a con.- siderably larger number of valves than heretofore needed. However, in comparison with the total cost of the pump and particularly the cost involved in any necessary stoppage of pump operation, the larger number of valves is not appreciable, especially since the valves 10, 12 and 15 may consist of check valves of simplest available type.
While the invention has been illustrated and described with reference to the example of a single-acting water ring pump with control plates or cones, the invention is equally well applicable to double-acting water ring pumps in which the suction and delivering performance occur twice during a single rotation of the rotor (as is known, for example, from the above-mentioned US. Pat. No. 1,718,294); and the invention is also applicable with water ring pumps in which the control plate members are not planar plates or cones but are cylindrical.
To those skilled in the art it will be obvious upon a study of the disclosure that such and various other modifications are applicable without departure from the essential features of my invention and within the scope of the claims annexed hereto.
l. Liquid-ring pump comprising a vane rotor, a housing structure enclosing said rotor and having suction and compression ports communicating with intervane spaces of said rotor at respective suction and pressure localities thereof, pump outlet means, pressure-responsive control valves located outside said housing structure, pressure lines connecting said control valves, respectively, with said compression ports of said housing structure, said valves having respective outlets communicating with said pump outlet means, and shut-off valve means serially connected with each of said respective control valves.
2. Liquid-ring pump according to claim 1, wherein said housing structure forms a chamber axially adjacent each side of said rotor, and said housing structure has control plate members located axially between each side of said rotor and the adjacent chamber, said suction and compression ports being provided in said control plate members.
3. Liquid-ring pump according to claim 1, comprising a manifold to which said respective outlets of said control valves are connected and which communicates with said pump outlet means.
4. In a liquid-ring pump according to claim 1, wherein said housing structure forms a chamber axially adjacent each side of said rotor, said pump outlet means comprising a compression duct communicating with said chamber, and a manifold to which said respective outlets of said control valves are connected and which communicates with said chamber.
5. In a liquid-ring pump according to claim 1, wherein said housing structure forms a chamber axially adjacent each side of said rotor, said pump outlet means comprising a compression duct communicating with said chamber and other compression duct means separate from said chamber, and a manifold to which said respective outlets of said control valves are connected and which communicates with said other duct means.
6. Liquid-ring pump according to claim 1, comprising a return line connected with said valve outlets and leading therefrom back to the suction side of the pump for increasing the pump efficiency at less than rated load. W
7. Liquid-ring pump according to claim 1, comprising a parallel branch line with shut-off means extending parallel to said valves in each of said pressure lines, said branch line being connected between respective locations communicating with said pressure lines upstream and downstream of the respective control valves.
8. Liquid-ring pump according to claim 3, comprising at least one parallel branch line with shut-off means extending parallel to said control valves in each of said pressure lines, said branch line being connected between respective locations communicating with said pressure lines upstream and downstream of the respective control valves, and a return line with shut-off means connecting said branch line to the suction side of the pump, and shut-off valve means interposed between said parallel branch line and said manifold.
9. In a liquid-ring pump according to claim 4, said shut-off valve means comprising two shut-off valves interposed in each of said pressure lines ahead and arrear of said control valve.