Rotary piston pump having direct drive

Abstract

The invention relates to a rotary lobe pump including a pump housing with a pump chamber, an inlet opening and an outlet opening. A first multi-lobed rotary piston is rotably mounted around a first axis in the pump chamber. A second multi-lobed rotary piston is rotably mounted around a second axis in the pump chamber and meshes with the first rotary piston. The first and second rotary pistons are rotated by a drive unit to create a fluid flow from the inlet opening to the outlet opening. The drive unit includes a first electric drive motor mechanically coupled with the first rotary piston and a second electric drive motor mechanically coupled with the second rotary piston.

Claims

1. A rotary lobe pump, comprising; a pump housing with a pump chamber, an inlet and an outlet opening, a first multi-lobe rotary piston arranged in the pump chamber and rotatably mounted about a first axis, a second multi-lobe rotary piston arranged in the pump chamber and rotatably mounted about a second axis that is spaced from the first axis, the second multi-lobe rotary piston intermeshing with the first multi-lobe rotary piston, wherein the first and second multi-lobe rotary pistons generate a fluid flow from the inlet to the outlet opening by rotating around the first and second axis, respectively, and a drive unit, which is mechanically coupled with the rotary pistons for driving the rotary pistons, wherein the first and second multi-lobe rotary pistons each comprise a number of N lobes, where N is greater than or equal to two, wherein each one of the lobes of the first and the second rotary multi-lobe pistons comprise a first end and a second end distal from the first end, wherein each one of the lobes extends helically along a peripheral surface of the rotary piston such that the first end is offset from the second end at an angle of at least 300° divided by N, and wherein the drive unit comprises a first electric drive motor that is mechanically coupled with the first multi-lobe rotary piston for driving the first multi-lobe rotary piston and a second electric drive motor that is mechanically coupled with the second multi-lobe rotary piston for driving the second multi-lobe rotary piston.

2. The rotary lobe pump according to claim 1, wherein the first drive motor directly drives a first shaft on which the first multi-lobe rotary piston is fixed in a torque-resistant manner, and wherein the second drive motor directly drives a second shaft on which the second multi-lobe rotary piston is fixed in a torque-resistant manner.

3. The rotary lobe pump according to claim 1, wherein the rotary lobe pump is gearless.

4. The rotary lobe pump according to claim 2, wherein at least one rotary piston is mounted rotatably on at least one sliding bearing that is lubricated by a conveyed fluid medium.

5. The rotary lobe pump according to claim 1, wherein a mechanical synchronization of the rotational movement of the first and second multi-lobe rotary pistons occurs through the intermeshing first and second multi-lobe rotary pistons.

6. The rotary lobe pump according to claim 1, wherein: each rotary piston has three lobes, each lobe extending helically along the peripheral surface such that the first end of the lobe is offset from the second end of the lobe by an angle of at least 100°, or each rotary piston has four lobes, each lobe extending helically along the peripheral surface such that the first end of the lobe is offset from the second end of the lobe by an angle of at least 75°, or each rotary piston has six lobes, each lobe extending helically along the peripheral surface such that the first end of the lobe is offset from the second end of the lobe by an angle of at least 50°.

7. The rotary lobe pump according to claim 1, wherein: the pump housing limits the pump chamber between the inlet and outlet opening on at least one side by a first inner peripheral wall section, and the lobes of the first multi-lobe rotary piston extend helically along the peripheral surface such that the angle at which the first end is offset from the second end of each respective lobe is so small that in each rotational position of the first multi-lobe rotary piston, at least one line of contact between the lobe and the first inner peripheral wall section forms a sealing line between the inlet and outlet opening.

8. The rotary lobe pump according to claim 1, wherein the pump chamber is arranged between the first and the second electric drive motor.

9. The rotary lobe pump according to claim 1, wherein the first and the second drive motor are: in a first operating mode, connected as a motor for the conversion of electric energy into flow energy, and in a second operating mode, connected as a generator for converting flow energy into electric energy.

10. A hydro-power system with a rotary piston motor, comprising: a motor housing with a motor chamber, an inlet and an outlet opening, a first multi-lobe rotary piston arranged in a pump chamber and rotatably mounted about a first axis, a second multi-lobe rotary piston arranged in the motor chamber and rotatably mounted about a second axis that is spaced from the first axis, the second multi-lobe rotary piston intermeshing with the first multi-lobe rotary piston, wherein the first and second multi-lobe rotary pistons are set into rotation about the first and the second axis, respectively, by a fluid flow from the inlet to the outlet opening, and a generator unit, which is mechanically coupled with the first and second multi-lobe rotary pistons in order to be driven by the first and second multi-lobe rotary pistons, wherein the first and second multi-lobe rotary pistons each comprises a number of N lobes, where N is greater than or equal to two, wherein each one of the lobes of the first and the second multi-lobe rotary pistons comprise a first end and a second end distal from the first end, wherein each one of the lobes extends helically along a peripheral surface of the rotary piston such that the first end is offset from the second end at an angle of at least 300° divided by N, and wherein the generator unit comprises a first electric generator that is mechanically coupled with the first multi-lobe rotary piston in order to be driven by the first multi-lobe rotary piston and a second electric generator that is mechanically coupled with the second multi-lobe rotary piston in order to be driven by the second multi-lobe rotary piston.

11. A method for pumping a liquid with a rotary lobe pump, wherein the liquid is conveyed through a pump chamber by means of a first and second rotary pistons, each comprising a number of N lobes, where N is greater than or equal to two, wherein each one of the lobes of the first and the second rotary pistons comprise a first end and a second end distal from the first end, wherein each one of the lobes extends helically along a peripheral surface of the rotary piston such that the first end is offset from the second end at an angle of at least 300° divided by N, and wherein the first rotary piston is driven by means of a first electric drive motor that is mechanically coupled with the first rotary piston and the second rotary piston is driven by means of a second electric drive motor which that is mechanically coupled with the second rotary piston.

12. A method for generating electric energy from a liquid pressure differential with a rotary piston motor, wherein with the liquid pressure differential, a first rotary piston and a second rotary piston intermeshing with the first rotary piston and the rotary piston motor are driven and accordingly, a first and a second axis are set into rotation, wherein the first and second rotary pistons each comprise a number of N lobes, where N is greater than or equal to two, wherein each one of the lobes of the first and the second rotary pistons comprise a first end and a second end distal from the first end, wherein each one of the lobes extends helically along a peripheral surface of the rotary piston such that the first end is offset from the second end at an angle of at least 300° divided by N, and in that the first rotary piston drives a first electric generator that is mechanically coupled with the first rotary piston, and the second rotary piston drives a second electric generator that is mechanically coupled with the second rotary piston.

13. The method according to claim 11, wherein the first and the second rotary pistons are intermeshing rotary pistons, and wherein the rotation of the intermeshing rotary pistons of the rotary lobe pump are not synchronized by means of a gear.

14. The rotary lobe pump of claim 4, wherein the first and the second shafts are mounted on sliding bearings lubricated by the conveyed fluid medium.

15. The rotary lobe pump of claim 7, wherein the pump housing limits the pump chamber between inlet and outlet opening with a first and a second inner peripheral wall section, and wherein the lobes of the second rotary piston extend helically over an angle that is so small that in each rotational position of the second rotary piston, at least one line of contact between each lobe and the second inner peripheral wall section forms a sealing line between the inlet and outlet opening.

16. The rotary lobe pump of claim 1, wherein the first multi-lobe rotary piston and the second multi-lobe rotary piston rotate oppositely to each other.

17. The method of claim 12, wherein the first and second rotary pistons are intermeshing rotary pistons and the rotation of the intermeshing rotary pistons of the rotary piston motor are synchronized through the lobes.

Description

(1) Preferred embodiments of the invention are explained through the following figures:

(2) FIG. 1 shows a longitudinal sectional view of a rotary lobe pump according to the invention.

(3) FIG. 2 shows a perspective view of a rotary piston with one half of the housing in a first embodiment, and

(4) FIG. 3 shows a view according to FIG. 2 with a second embodiment of a rotary piston.

(5) FIG. 1 shows an apparatus that can be operated as a rotary lobe pump or rotary piston motor, consisting of a total of four sub-assemblies: A foundation frame 10, and attached thereon, a housing unit 20, which is flanked by a left electric drive motor 40 and a right electric drive motor 50, both of which are likewise attached to the foundation frame 10.

(6) The drive motors 40, 50 are designed as three-phase motors and can, in a first operating mode, be supplied with electric energy in order to each drive a rotary piston 21, 22 in the rotary lobe pump 20 via a drive shaft 41, 51. In a second operating mode, the drive motors 40, 50 can be operated as generators 63 and 64, respectively. In this second operating mode, a torque is transferred from the rotary piston 21 or 22 via the drive shaft 41, 51 to the generator 63 or 64, and the generator 63 or 64 generates an electric energy that can be stored temporarily or fed into a network.

(7) The housing unit 20 comprises a housing 30 which is constructed in multiple parts. On the housing 30, inlet and outlet openings are arranged which can be connected accordingly by connecting flanges; in FIG. 1, the flange 31 of the outlet opening is visible.

(8) The two rotary pistons 21, 22 are arranged in a pump chamber 35 which is limited on all sides by the pump housing 30 having first and second inner peripheral wall sections 30a, 30b. The rotary pistons 21, 22 are attached to rotary shafts 23, 24 in a torque-resistant manner. In the second operating mode, pump chamber 35 and the pump housing 30 correspond to a motor housing 65.

(9) As can be seen in FIG. 1, both rotary pistons 21, 22 comprise a plurality of lobes 21a/b, 22a/b which interlock with one another in the manner of teeth on two toothed wheels and thus intermesh with one another. Through this intermeshing of the lobes of the rotary pistons, the shafts 23, 24 can, necessarily, only rotate at matching rotational speeds.

(10) The rotary shaft 23 of the upper rotary piston 21 is mounted in a right-side sliding bearing 23a and a left-side slide bearing 23b. Both sliding bearings 23a, b are designed as oil-free bearings and are lubricated by the liquid that is conveyed through the pump chamber. For this purpose, appropriate drainage lines 60, 61 are provided. The drainage line 60 opens into a housing cover 32, the drainage line 61 opens into a housing cover 33 on the right side of the rotary lobe pump.

(11) The rotary shaft 23 extends through the left housing cover 32 to a coupling unit 42, by means of which the rotary shaft 23 is coupled with drive shaft 41 of the drive motor 40 in a torque-resistant manner. The rotary shaft 23 is mounted in the right housing cover 33, but does not extend through this housing cover.

(12) The rotary shaft 24 extends through the right housing cover 33 to a coupling 52, by means of which it is coupled with drive shaft 51 of the drive motor 50 in a torque-resistant manner. This rotary shaft 24 is, in turn, mounted in the right housing cover 33, but does not extend through this housing cover.

(13) As can be seen, the drive motor 40 is coupled directly with the rotary shaft 23 via the coupling 42, driving said rotary shaft or being driven by it in generator mode. Likewise, the drive motor 50 is coupled directly with the rotary shaft 24 via the coupling 52, driving said rotary shaft or being driven by it in generator mode. The rotary lobe pump of the invention according to FIG. 1 does not comprise any step-down or step-up gear or other gearing for synchronizing the rotational movement of the rotary pistons 21, 22.

(14) FIG. 2 shows a three-lobe rotary piston 121 having a total of 3 lobes 121a, b, c. Each of the lobes is wound across the entire axially extending length of the rotary piston over 120° along a helical line. A sealing line 125 is shown as a helical hatched line.

(15) The rotary piston 121 is shown in FIG. 2 in a housing half-shell 134, which defines an upper limiting edge 134a of an inlet opening and an upper limiting edge 134b of an outlet opening.

(16) FIG. 3 shows a rotary piston 221 with a total of 4 lobes 221a-d. Each lobe is wound helically along the entire axial length of the rotary piston 221 over a circumferential angle of 90°.

(17) The rotary piston 221 is, in turn, shown in a housing half-shell 234, which corresponds to the housing half-shell 134.

(18) Basically, it is important to understand that during operation, the rotary pistons 121, 221 act together and intermesh with a rotary piston positioned vertically underneath the other. In terms of its number of lobes and the angle over which a lobe extends helically across the length of the rotary piston, this second rotary piston corresponds to the rotary pistons 121 or 221. However, the underlying rotary piston is designed such that the lobe extends in the opposite rotational direction, so that an intermeshing of the two rotary pistons becomes possible.