Abstract: A vertical pump includes: a rotary shaft; multi-stage impellers; a casing accommodating the multi-stage impellers; a mechanical seal provided in a penetration part of the casing for the rotary shaft; a balance sleeve, the balance sleeve being positioned between a final stage impeller of the multi-stage impellers and the mechanical seal in the penetration part for the rotary shaft; an intermediate chamber provided between the rotary shaft and the casing and provided on an opposite side of the multi-stage impellers across the balance sleeve in an axial direction of the rotary shaft, the intermediate chamber communicating with an intermediate stage impeller among the multi-stage impellers; a low pressure chamber provided between the rotary shaft and the casing, the low pressure chamber communicating with a low pressure side compared to the intermediate chamber; and a partition wall part dividing the intermediate chamber and the low pressure chamber.

Abstract: A vertical pump includes: a rotary shaft; multi-stage impellers; a casing accommodating the multi-stage impellers; a mechanical seal provided in a penetration part of the casing for the rotary shaft; a balance sleeve, the balance sleeve being positioned between a final stage impeller of the multi-stage impellers and the mechanical seal in the penetration part for the rotary shaft; an intermediate chamber provided between the rotary shaft and the casing and provided on an opposite side of the multi-stage impellers across the balance sleeve in an axial direction of the rotary shaft, the intermediate chamber communicating with an intermediate stage impeller among the multi-stage impellers; a low pressure chamber provided between the rotary shaft and the casing, the low pressure chamber communicating with a low pressure side compared to the intermediate chamber; and a partition wall part dividing the intermediate chamber and the low pressure chamber.

Abstract: A double casing type pump and a performance adjusting method allow for adjustment of the performance of the pump, especially the head of the pump, without large-scale work or component disassembly. The pump includes impellers fixed to a rotation shaft, an inner casing shrouding the impellers, an outer casing shrouding the inner casing and having a suction opening and a discharge opening. A space is formed between the inner and outer casings that communicates with the discharge opening. A bypass hole connects the space to the working fluid passage in the inner casing and has a throat diameter adjusting member. A plurality of throat diameter adjusting members are prepared in advance, each member having different throat area. One of the throat diameter adjusting members is selected so that the performance of the pump remains within a predetermined range.

Abstract: Providing a double casing type pump and a head adjusting method thereof, wherein, the performance of the pump, especially, the head of the pump can be adjusted without large-scale work as well as without component disassembly. A double casing type pump, comprising: a plurality of impellers fixed to a rotation shaft, an inner casing that shrouding the impellers; an outer casing shrouding the inner casing and having a suction opening and a discharge opening; wherein, the pump further comprises: a space formed between the inner casing and the outer casing, the space communicating with the discharge opening; a bypass hole connecting the space to the working fluid passage in the inner casing, the pressure in the working fluid passage being lower than the stagnation fluid in the space; and, the bypass hole comprises a throat diameter adjusting member having a through-hole therein for determining the throat area of the bypass hole.