Rotary piston pump and casing half-shells for same

Abstract

The invention relates to a rotary lobe pump for conveying a fluid medium containing solids, comprising an inlet and an outlet for the medium being conveyed, and further comprising a pump casing and two rotary lobes arranged in said pump casing and having intermeshing rotary lobe vanes. According to the invention, the pump casing has two opposite casing half-shells which seal the pump casing fluid-tightly. The casing half-shells are double-walled.

Claims

1. A rotary lobe pump for conveying a fluid medium containing solids, the rotary lobe pump comprising an inlet and an outlet for the medium being conveyed, and further comprising a pump casing, a first rotary lobe rotatable about a first axis of rotation, and a second rotary lobe rotatable about a second axis of rotation, wherein said first and said second rotary lobes are arranged in said pump casing and have intermeshing rotary lobe vanes, wherein the pump casing comprises: a first casing half-shell having a double-walled first body, the double-walled first body comprising: a first outer wall having a first half-cylindrical shape that curves between and terminates adjacent to first side surfaces of the first casing half-shell; and a first inner wall which is arranged at a uniform first radius from said first axis of rotation and which spans an angle of 180 about said first axis of rotation; a second casing half-shell having a double-walled second body, the double-walled second body comprising: a second outer wall having a second half-cylindrical shape that curves between and terminates adjacent to second side surfaces of the second casing half-shell; and a second inner wall which is arranged at a uniform second radius from said second axis of rotation and which spans an angle of 180 about said second axis of rotation, wherein said uniform second radius is equal to said uniform first radius; wherein the first casing half-shell and the second casing half shell are arranged opposite one another so that the first side surfaces of the first casing half-shell and the second side surfaces of the second casing half shell face one another and are separated from each other by a distance; and an intermediate casing that extends across the distance, wherein the first casing half-shell and the second casing half-shell are connected fluid-tightly to each other by at least the intermediate casing to seal the pump casing fluid-tightly and define boundaries of an oblong chamber in which the first rotary lobes and the second rotary lobe are located.

2. The rotary lobe pump according to claim 1, wherein a cavity is formed between an inner wall of one of the two casing half-shells and the outer wall of the one of the two casing half-shells.

3. The rotary lobe pump according to claim 2, wherein one or more struts extending from the inner wall to the outer wall are formed in the cavity of the one of the two casing half-shells.

4. The rotary lobe pump according to claim 2, wherein one or more ribs extending from the inner wall to the outer wall are formed in the cavity of the one of the two casing half-shells.

5. The rotary lobe pump according to claim 2, wherein the outer wall of the one of the two casing half-shells has a through hole which is formed to receive or dispense a coolant into or out of the cavity between the inner wall and the outer wall.

6. The rotary lobe pump according to claim 1, wherein the distance between said two casing half-shells can be adjusted according to the level of wear.

7. The rotary lobe pump according to claim 1, wherein the intermediate casing has an inner wall and an outer wall, and a cavity is formed between the inner wall and the outer wall of the intermediate casing.

8. The rotary lobe pump according to claim 1, wherein the opposite casing half-shells and the intermediate casing have axial end faces which are connected and clamped by threaded rods, said threaded rods being arranged on an inner side in a cavity.

9. The rotary lobe pump according to claim 1, wherein the first and second casing half-shells form a first pair of casing half-shells and further comprising at least one second, other pair of two oppositely arranged casing half-shells, which are arranged axially adjacent to the first pair of casing half-shells such that: the first casing half-shell of the first pair has an axial end face and said axial end face is connected to an axial end face of a casing half-shell of the second, other pair; and the second casing half-shell of the first pair has an axial end face, and said axial end face is connected to an axial end face of a second casing half-shell of the second, other pair.

10. The rotary lobe pump according to claim 1, further comprising replaceable spacer elements for axially extending the intermediate casing and/or comprising replaceable spacer elements for axially extending the casing half-shell.

11. A method for producing the rotary lobe pump of claim 1, wherein the first and second casing half-shells are formed by steps comprising: providing or producing a casting mould for a casing blank, the casting mould being formed as a negative of a casing blank and adapted to produce the casing blank integrally in such a way that said casing blank has two half-shell sections and is double-walled, producing the casing blank by introducing free-flowing material casting material into the casting mould and hardening the free-flowing casting material, processing the casing blank so that a cylindrical inner surface of the casing blank results, and separating the half-shell sections of the casing blank so that the first and second casing half-shells result, each being double-walled.

12. The method according to claim 11, wherein a cavity is formed between an inner wall of the casing blank and an outer wall of the casing blank.

13. The method according to claim 12, wherein the casing blank is produced in such a way that one or more struts extending from the inner wall to the outer wall are formed in the cavity of the casing blank.

14. The method according to claim 12, wherein the casing blank is produced in such a way that one or more ribs extending from the inner wall to the outer wall are formed in the cavity of the casing blank.

15. The method according to claim 11, wherein the half-shell sections of the casing blank are separated by removal of material or without removal of material.

16. The method according to claim 11, wherein processing of the casing blank so that a cylindrical inner surface of the casing blank results is performed using a cutting technique.

17. The method according claim 11, comprising the steps of: thermal aftertreatment of the casing blank following hardening of the free-flowing casting material, so that internal stress in the casing blank is reduced.

Description

(1) The invention shall now be described in greater detail with reference to preferred embodiments and to the attached Figures, in which

(2) FIG. 1 shows a schematic cross-sectional view of a pump casing of a rotary lobe pump;

(3) FIG. 1a shows another cross-sectional view of the pump casing of FIG. 1, shown with an intermediate casing.

(4) FIG. 2 shows a side view of a casing half-shell according to the present invention;

(5) FIG. 3 shows another side view of the housing half-shell in FIG. 2;

(6) FIG. 4 shows a cross-sectional view of the casing half-shell in FIGS. 2 and 3; and

(7) FIG. 5 shows a spatial cross-sectional view of the casing half-shell in FIGS. 2 to 4;

(8) FIG. 1 shows the basic structure of pump casing 1 of a rotary lobe pump according to the present invention. Pump casing 1 has two casing half-shells 3. The casing half-shells 3 are arranged at a distance 5 from each other. Distance 5 preferably corresponds to the distance between two drive axles 13. Drive axles 13 are associated with a gear transmission (not shown), are arranged parallel in a plane 11 and are each connected torque-resistantly by means of a tongue 9 to a rotary lobe 7.

(9) The casing half-shells 3 have side surfaces 15 which face each other. Side surfaces 15 are designed to be joined fluid-tightly to an intermediate casing 100 (see FIG. 1a). The intermediate casing defines the distance 5 to be preferably set between the casing half-shells 3. As shown in FIG. 1a, a spacer element 100a is disposed between the intermediate casing 100 and the casing half-shells 3.

(10) The casing half-shells each have an inner surface 19. Each inner surface 19 preferably has a semi-cylindrical contour. In the position shown, rotary lobe 7 on the left in FIG. 1 forms a conveying cavity 17 between itself and inner surface 19 of associated casing half-shell 3.

(11) The double-walled structure of casing half-shell 3 is shown in more detail in the following Figures.

(12) FIGS. 2 and 3 each show a projection of a side view of a casing half-shell 3 according to the present invention. Casing half-shell 3 has an end face 21. End face 21 is preferably planar and can be brought into contact with a matching surface of a cover (not shown). Between an outer surface 23 and inner surface 19, casing half-shell 3 has a number of through holes 25 in end face 21, which extend from end face 21 into a cavity (see FIG. 4). Through holes 25 are distributed evenly along end face 21. The substantially cylindrical outer surface 23 has a number of planar surface sections 27 along its length. Surface sections 27 are adapted to receive radial through holes 29, fit bores or the like.

(13) FIGS. 4 and 5 each show cross-sectional views of a casing half-shell according to the present invention. FIG. 4 shows a cross-sectional view through a casing half-shell according to one preferred embodiment of the present invention, whereas FIG. 5 shows a spatial view of a quarter section of the casing half-shell according to the invention. Reference is made, with regard to identical reference signs, to the above description of FIGS. 1 to 3. As shown in FIG. 4, casing half-shell 3 has an inner wall 31 and an outer wall 33. A cavity 32 is formed between inner wall 31 and the outer wall. The casing half-shells are double-walled. A number of webs 35 are formed between inner wall 31 and outer wall 33. Webs 35 each extend between inner wall 31 and outer wall 33. Webs 35 are adapted to support inner wall 31 and outer wall 33 against each other. Through hole 29 shown here extends from one of the planar sections 27 of outer surface 23 through the outer wall 33 into cavity 32. Through hole 29 is selectively formed as an inlet or an outlet and is designed to receive and/or discharge a coolant and/or heating medium and/or is designed to receive a filling material such as a vibration-absorbing or sound-absorbing material, with which cavity 32 can be filled. Sensors, or data lines or power lines, can also be optionally laid in cavity 32 by means of through hole 29. A casing half-shell 3 preferably has a plurality of through holes 29.

(14) Outer wall 33 and inner wall 31 are connected to each other in a lateral section 37 and preferably merge integrally with each other.

(15) Side surfaces 15 are parallel to each other. The inner surface 19 extending on the inside between side surfaces 15 is semi-cylindrical and spans an angle of 180.

(16) FIG. 5 shows that a reinforcement 39 is formed in cavity 32 in the region of through hole 29. Reinforcement 39 provides further support for inner wall 31 against outer wall 33 in the region of through hole 29.