Self-priming Centrifugal Pump Auxiliary Suction Conduit
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Solution Overview
Problem
Self-priming centrifugal pumps experience performance decay and limited maximum flow rate due to incipient cavitation at the ejection nozzle, leading to efficiency and pressure losses beyond a certain flow rate.
Innovation Solution
Incorporation of an auxiliary suction conduit with a non-return valve that connects the suction opening directly to the inlet of the pumping chamber, allowing direct liquid flow at high pressures and preventing cavitation, while maintaining high pressure at low flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the flow rate is increased in a self-priming centrifugal pump, then the productivity is improved, but incipient cavitation occurs at the ejection nozzle causing performance decay
Solution Approach 1:
The suction path is segmented into two separate conduits: an auxiliary suction conduit that provides a dedicated high-pressure flow path from the suction opening directly to the impeller inlet, and a recirculation suction conduit that handles the recirculated flow. This segmentation allows the high-pressure auxiliary path to prevent cavitation while the recirculation path maintains priming function, enabling increased flow rates without performance decay.
Solution Approach 2:
The auxiliary suction conduit acts as an intermediary element that introduces high-pressure liquid directly from the suction opening to the impeller inlet area. This intermediary path compensates for the pressure drop and cavitation tendency in the recirculation system, allowing the pump to operate at higher flow rates while maintaining performance stability.
2Productivity
If the flow rate is increased, then the productivity is improved, but the efficiency decreases due to cavitation
Solution Approach 1:
The suction system is divided into two functional conduits: the auxiliary suction conduit that efficiently delivers high-pressure flow with minimal energy loss, and the recirculation suction conduit that maintains priming. This segmentation reduces overall energy losses by preventing cavitation in the main flow path while keeping the recirculation system optimized for its specific function.
3Productivity
If the flow rate is increased, then the productivity is improved, but the maximum pressure is reduced due to cavitation
Solution Approach 1:
The auxiliary suction conduit serves as a pressure-maintaining intermediary that introduces high-pressure liquid directly to the impeller inlet. This compensates for the pressure drop that would normally occur at high flow rates, allowing the pump to maintain maximum pressure even when operating at increased productivity levels.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables increased maximum flow rate and efficiency while maintaining high performance levels, avoiding cavitation and extending operational efficiency beyond traditional pump limits.
Implementation Method 1
a non-return valve (35) arranged inside said auxiliary suction conduit (34)
Implementation Method 2
The recirculation of the liquid is carried out through the ejection nozzle; the liquid, on exiting from the pumping chamber of the impeller group, fills the internal cavity of the pump body
Data Source
Figure 1
Figure 2~3
AI summary
The self-priming centrifugal pump comprises a pump body (10) having an inner cavity (11 ) having a longitudinal axis (A) arranged in a horizontal position in use configuration which divides said inner cavity (11) into an upper zone (S) and a lower zone (I); a suction opening (12) made on a front surface (13) of said pump body (10) at said upper zone (S); a pumping chamber (20) associated with said pump body (10) and having at a frontal part thereof an axial inlet opening (21); an impeller group (22) arranged inside said pumping chamber (20); an ejector group (30) which extends into said inner cavity (11) of the pump body (10) and comprises an ejection nozzle (31) and an suction conduit (32) shaping a divergent profile, connected, at the wider section thereof to the inlet opening (21) of the pumping chamber (20); an auxiliary suction conduit (34) arranged inside said inner cavity (11 ) of the pump body (10), at said upper zone (S), and adapted to put said suction opening (12) in direct communication with said inlet opening (21) of the pumping chamber (20).