Barrel Multistage Pump Discharge Positioning
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Solution Overview
Problem
Conventional barrel-type multistage pumps experience significant fluid loss due to velocity non-uniformity and flow disorder at the junction between the connecting channel and discharge pipe, leading to increased energy consumption and pump size, which existing modifications fail to adequately address.
Innovation Solution
The discharge position of the cylindrical flow channel is relocated near the central axis of the discharge pipe, with a uniform axial velocity distribution and controlled deceleration rate in the connecting channel to minimize fluid loss, achieved through specific geometric modifications such as inclined connecting channels and guide blades, and varying cross-sectional areas to ensure smooth flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the junction part between the connecting channel and cylindrical flow channel is positioned apart from the center line of the discharge pipe to shorten pump length, then the axial length and size of the pump are reduced, but velocity non-uniformity and flow disorder occur at the discharge position causing significant fluid loss
Solution Approach 1:
The patent applies local quality by creating a localized expansion section in the discharge channel with a specific curvature radius. This local geometric modification ensures uniform velocity distribution and smooth flow transition at the critical discharge position, while the rest of the pump structure maintains its compact design. The expansion section acts as a localized flow conditioning zone that resolves the fluid loss problem without compromising the overall pump length reduction.
Solution Approach 2:
The patent introduces a radial expansion dimension in the discharge channel by positioning the junction part apart from the center line and creating an expansion section with increased cross-sectional area. This dimensional change allows the flow to adjust smoothly from the connecting channel to the discharge pipe, transforming the flow pattern from disordered to uniform without requiring axial length extension.
2Ease of manufacture
If the cross-sectional area of the cylindrical flow channel is kept constant to simplify structure, then manufacturing is easier, but velocity non-uniformity increases causing flow separation and disorder
Solution Approach 1:
Instead of making the entire cylindrical flow channel variable in cross-section, the patent applies local quality by creating an expansion section only at the discharge end. This localized geometric change improves flow uniformity where it is most needed (at the discharge position) while keeping the majority of the channel structure simple and easy to manufacture.
3Loss of energy
If the connecting channel is positioned to optimize flow direction, then fluid loss is reduced, but the pump size and weight increase
Solution Approach 1:
The patent uses local quality by creating a focused expansion section with specific curvature at the junction area. This localized flow conditioning structure minimizes fluid loss through proper flow direction control, while the rest of the pump structure remains compact and lightweight. The expansion section is precisely positioned and dimensioned to achieve flow optimization without adding unnecessary weight.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6B
AI summary
The present invention provides a barrel-type multistage pump in which velocity distribution in the axial direction on the cross-section of a rotating flow channel (8) is uniformed to suppress a fluid loss in the last stage. A barrel-type multistage pump includes: centrifugal impellers (1) that are provided in plural stages; an inner casing (2) that covers the centrifugal impellers (1), and includes diffusers (6) that are provided on the downstream sides of the respective centrifugal impellers (1) in plural stages, return channels that are provided on the downstream sides of the diffusers (6) to guide the flow of a fluid to the centrifugal impeller (1) in the next stage, and return vanes (7) that are arranged at the respective return channels; and a cylindrical outer casing (5) that has a suction pipe (31) and a discharge pipe (41), wherein a cylindrical rotating flow channel (8) connected to the discharge opening (4) is provided between the outer casing (5) and the inner casing (2), a connecting channel (9) is provided between the rotating flow channel (8) and the diffusers (6) to connect therebetween, the shape of the connecting channel (9) is inclined on the suction opening (3) side in the rotary shaft (10) direction, and an outflow position of the connecting channel (9) in the rotating flow channel (8) is located near the central axis of the discharge pipe (41).