ROTARY PISTON PUMP

Abstract

Rotary piston pump (1) with a pump housing (2) in which counter-rotating, rolling rotary pistons (5, 6) are held on parallel, spaced-apart piston shafts (7, 8) in a working chamber (12), wherein the piston shafts (7, 8) are led out of the working chamber (12) via a shaft outlet - and are preferably mounted with their end sections in a gear housing (18) - and each shaft outlet is sealed by means of a mechanical seal set (19) comprising a shaft sleeve (15) which is pushed onto the respective piston shaft (7, 8) and connects a part of the mechanical seal (19) to the piston shaft (7, 8) in a rotationally fixed manner, characterized in that at the end of the shaft sleeve (15) facing away from the working chamber (12), a driving ring (24) is fixed in a rotationally fixed manner on the piston shaft (7, 8), which driving ring is positively connected to the shaft sleeve (15). and thus forces the shaft sleeve (15) to follow the rotary movement of the piston shaft (7,8), characterized in that the driving ring (24) has on its end face facing the working space (12) a plurality of axial projections (28) which engage in a form-fitting manner, preferably without play, in complementary recesses (29) on the end face of the shaft sleeve (15) facing away from the working space (12).

Claims

[1] Rotary lobe pump (1) with a pump housing (2) in which counter-rotating, mutually rolling rotary lobes (5, 6) are held on parallel, spaced-apart piston shafts (7, 8) in a working chamber (12), wherein the piston shafts (7, 8) are led out of the working chamber (12) via a shaft outlet - and are preferably mounted with their end sections in a gear housing (18) - and each shaft outlet is sealed by means of a mechanical seal set (19) comprising a shaft sleeve (15) which is pushed onto the relevant piston shaft (7, 8) and connects a part of the mechanical seal (19) to the piston shaft (7, 8) in a rotationally fixed manner, characterized by that at the end of the shaft sleeve (15) facing away from the working chamber (12), a driving ring (24) is fixed in a rotationally fixed manner on the piston shaft (7, 8), which is positively coupled to the shaft sleeve (15) and thus forces the shaft sleeve (15) to follow the rotary movement of the piston shaft (7, 8), characterized by that the driving ring (24) has on its end face facing the working space (12) a plurality of axial projections (28) which engage in a form-fitting manner, preferably without play, in complementary recesses (29) on the end face of the shaft sleeve (15) facing away from the working space (12). [2] Rotary piston pump (1) according to claim 1, characterized by that the driving ring (24) simultaneously has a race for the running surface (25) of the seal (26), which is preferably designed in the form of a radial shaft sealing ring and which ensures the sealing of the bearings or the gear (27), which synchronizes the piston shafts (7, 8), in the direction of the working chamber (12). [3] Rotary piston pump (1) according to claim 2, characterized by that the driving ring (24) is polished in the region of its running surface (25) or provided with a comparable finish and is hardened and / or provided with a wear protection layer at least in the region of its running surface (25). [4] Rotary piston pump (1) according to claim 1, characterized by that the projections and recesses (28, 29) are formed either by a spur toothing or by a structure in the manner of a tower crown provided with battlements. [5] Rotary piston pump (1) according to one of the preceding claims, characterized by that the driving ring (24) is clamped to the piston shaft (7, 8) in a rotationally fixed manner by one or more radial pressure screws (30), preferably in the form of grub screws. [6] Rotary piston pump (1) according to one of the preceding claims, characterized bythat the shaft sleeve (15) is extended on its side facing away from the working chamber (12) to such an extent that it integrally provides a running surface (31) for an additional seal (32), so that a flushing chamber (42) is formed between the mechanical seal (19) and the additional seal (32), which flushing chamber can be periodically supplied with flushing liquid in order to flush out solid deposits that have entered the area of the mechanical seal (19). [7] Rotary piston pump (1) according to one of the preceding claims, characterized by that the driving ring (24), the shaft sleeve (15) and the rotary piston fastening are designed and arranged such that the shaft sleeve (15) is axially clamped between the driving ring (24) and the rotary piston (5, 6). [8] Rotary piston pump (1) according to claim 7, characterized by that for the purpose of controlling the axial tension of the shaft sleeve (15) one or more spacer rings are inserted between the rotary piston (5, 6) and the shaft sleeve (15).

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