Rotary pump

Aug. 1, 1933.

1,920,484

O. SIEMEN ET AL

ROTARY PUMP

Filed May 7, 1930

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Patented Aug. 1,. 1933

1,920,484

UNITED STATES PATENT OFFICE

1,928,484

BOTABY PUMP

Oita Siemen and Johannes Hinsch, Itzehoe, Germany

Application May 7, 1930, Serial No. 450,516, an® _; in Italy May 27, 1929

Claims. (Cl. 103—96)

The present in vention. relates to rotary ptimps of the type in which a vaned impeller wheel rotates hi a surrounding casing and the pumping action is obtained by escape of an auxiliary S pumping liquid from the pockets between the vanes, thereby forming a vacuum which draws a fluid being pumped into the pockets, and the subsequent return of the pumping liquid into the pockets, thereby creating a pressure on the S® fluid being pumped to force the latter fluid through an outlet.

Rotary pumps of this type have been constructed in which the impeller is eccentric to the surrounding chamber thereby forming a passage US outside the periphery of the wheel, and varying in width between the tips of the vanes and the casing; in this type of pump the pumping or auxiliary liquid is caused to leave the pockets between the vanes by centrifugal force at the wide 20 part of the passage and is forced back into the pockets at the narrow part of the passage. Because of the friction and energy losses the efficiency of a pump of this construction is quite low. Another construction which has been in 2S use provides a rotor in the form of a vaned wheel enclosed in a neatly fitting casing, one or each side wall of which is formed with a segmental channel, one end of which communicates with an induction and the other with an exhaust port. 30 The pump and the suction pipe must be primed with water which, owing to frictional contact with the wheel, is caused to flow through the channel from the induction to the exhaust port. Gaseous fluids cannot be pumped through a de35 vice of tljis type since it is impossible to build up a satisfactory pressure differential between the inlet and exhaust ports.

The principal objects of the present invention . are to produce a pump of this type which will 40 pump gases as readily as liquids, and which provides a pressure head much higher than has been previously obtained in similar pumps, and the invention consists in arranging the inlet and exhaust ports separately from a segmental pump-. 45 Ing channel, ne.ar the opposite ends thereof and between the channel and the axis of rotation of the wheel or rotor, so that a liquid circulating with the vanes through the casing will, by its entrance into and exit from the channel, pro⁶⁰ duce suction at one port and pressure at the other.

Fig. 1 of the accompanying drawing represents a cross sectional view of, the improved pump, parts of the rotor being broken away to show ⁵⁵ the channel construction.

Fig. 2 is an axial section of the same.

Fig. 3 is another cross section of the pump . taken in an opposite direction to that of Fig. 1, parts of the rotor being broken away to show the channel construction. go

Fig. 4 is a view of the rotor.

Fig. 5 is a development of the channels.

Fig. 6 is a cross-section through the channel and the wheel pockets, showing diagrammaticaliy the flow of water. - S5

Like reference characters refer to like parts in the different figures.

The pump comprises a rotor in the form of a vaned wheel or rotor, having a substantially circular hub and radial vanes, the wheel being en- 70 closed concentrically in a neatly fitting casing which may be formed in two’halves a and b secured together in any desired manner. In the casing walls at opposite sides of the rotor, arcuate identical segmental pumping channels d and / 75 are formed, the outer radius of the channels being substantially equal to the radius of the impeller wheel, which extend about the axis of rotation of the wheel from and to a point where the vanes move in an upward direction, the ends of the 80 channels being spaced from each other. The channels are open' only towards the rotor throughout their length and are gradually reduced in depth at both ends to merge with the casing wall as shown in Fig. 5, thereby providing 85 a cross-section gradually increasing or diminishing in area to cause the pumping liquid to be gradually withdrawn or returned to the pockets between the blades, as will be later pointed out. The channels, are coextensive, so that correspond- 90 ing ends are opposite each other and the openings in the channels d and f are arranged on opposite sides of the tips of the vanes so that the sides of the outer portions of the vanes pass over the openings in the channels; the channels are so 95 arranged as slightly to approach the axis of the rotor in the direction of rotation, that is, the channels are nearer the rotor axis at the point where the liquid is discharged from the channel into the pockets of the impeller than at the point ¹⁰⁰where the liquid flows into the channels from the impeller pockets. This results in a lowered centrifugal force so that, as the liquid reenters the pockets, the energy losses betwen the wheel and the pumping liquid will be .substantially di- ¹⁰⁵minished.

An intake port e is arranged parallel to and adjacent that end of the channel d into which the liquid first flows from the impeller pockets. The port e is arranged between the end of the ¹¹⁰

1,920,484 channel and the axis of rotation of the rotor and opens into the pockets adjacent the hub of the rotor. At the end remote from the tapering end of channel d, the intake port is arranged to provide a channel which becomes less deep in the direction of rotation of the impeller to merge with the side of the casing as shown in Fig. 1; this channel construction causes the fluid being pumped to be swept along by the vanes and gradually directed into the pockets. The port is connected in any desired manner through the casing to the intake of the pump.

An exhaust port g is arranged on the opposite side of the impeller, parallel to and adjacent the end of the channel f which is remote from the intake port e, that is, adjacent the end of the channel which directs the pumping liquid back into the pockets of the impeller. This port g is arranged between the channel f and the axis of rotation of the impeller and opens to the impeller pockets adjacent the hub; the port is connected through the casing in any desired manner with the exhaust outlet of the pump as shown in Fig. 2. This port, at the end remote from the end of the channel /, is provided with a channel which diminishes in area in a direction opposite to the direction of rotation of the impeller to merge gradually with the side of the casing.

In operation the pump casing is primed with a pumping liquid. With the rotor c moving in the direction of the arrow, the pumping liquid will be urged by centrifugal force against the circumferential inner surface of the casing. Considering now an impeller pocket on the impeller wheel in a position in which there is no communication between the pocket and any channel, that is, a pocket as at h (Fig. 3) and rotating in the direction indicated; as the pocket approaches the openings of the Channels d and / and the inlet opening e and passes along where the channels are gradually becoming larger in area, the pumping liquid is gradually carried outwardly by centrifugal force into the channels, forming a vacuum in the portion of the pocket adjacent the hub and thereby drawing the fluid being pumped into the pocket through the inlet opening e which is now in communication with the base portion of the pocket. As the pocket continues its rotary movement, the inlet opening is closed and the fluid being pumped is carried within the pocket until a position is reached in which the exhaust port is in communication with the pocket. In this position, the channels d and / are diminishing in area, and thereby force the pumping fluid into the pocket and force the fluid being pumped out through the exhaust port. The same pumping action occurs with relation to each individual pocket so that the action is uniform. The construction of the pump makes it equally adapted for pumping gases or liquids or a mixture of the two as above pointed out and Is will be apparent that, in pumping a liquid, the liquid being pumped provides, of itself, the auxiliary pumping liquid.

The pump of the present construction provides an extremely high pressure head which results from the action of the pumping liquid between the pumping channels and the rotor as shown diagrammatically in Fig. 6. The centrifugal force applied to the pumping liquid by rotation of the impeller procures a flow of liquid from A toward B where it is directed axially by engagement with the periphery of the casing to C. This movement of the water produces at A a lower pressure than exists at D and a circular current is produced as shown by the arrows. To this circular motion is added the rotary motion of the wheel which imparts to the water a rather high velocity; the latter is partially converted into pressure in the lateral channels, part of the water 80 reentering the wheel at D with a reduced speed and receiving an additional impulse from the wheel. The result is a helical movement of the water through the wheel pockets and the side channels and every complete loop of the helix 85 transmits a certain amount of energy from the wheel to the water comparable to the individual stage of a multi-stage pump.