Abstract: A submersible pump assembly comprises a gear transmission (10) and an equalizer (24). The gear transmission (10) includes a transmission housing (12) filled with lubricating fluid in which an input shaft (14, 102, 120) adapted to be driven and an output shaft (16) for driving a pump are supported. A transmission step (22) is provided to reduce the rotational speed of the input shaft (14, 102, 120). The equalizer (24) adapts the lubricating fluid pressure in the transmission housing (12) to ambient pressure. The equalizer (24) is arranged within the transmission housing (12) next to the transmission step (22) so as to distribute the heat generated at the transmission step (22) throughout the lubricating fluid.

Abstract: A stator jacket (12) and a stator lining (22) of elastomeric material together form a tubular pump stator (10) the ends (20) of which are connected to a connecting piece (36) of a casing portion (32, 34) each. The stator jacket (12) has at least one parting area (14) extending throughout its length. This and the region of the stator lining (22) located radially inside thereof as well as the junctions of the connecting pieces (36) with the stator jacket (12) are designed such that the pump stator (10) will burst in at least one parting area (14, 16) when a predetermined positive internal pressure is exceeded. This provides pressure relief before a risk of explosion can develop when explosives are being conveyed.