Adjustable Seal Ring Clearance in Centrifugal Slurry Pumps
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Solution Overview
Problem
Centrifugal slurry pumps face wear and efficiency issues due to abrasive solid particles trapped between the impeller and static volute, particularly on the suction side, leading to increased slurry recirculation and reduced hydraulic performance, with existing adjustment methods being time-consuming and costly.
Innovation Solution
The apparatus includes a seal member with threaded apertures and adjusting screws that allow for precise adjustment of the impeller/ring clearance by rotating and axially moving the seal member relative to the impeller, using left- or right-handed threads and a raised intermediate portion to control movement, facilitating easier and more precise sealing without disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the entire impeller is moved to adjust clearance, then the clearance size can be changed, but the pump must be shut down and the operation is time-consuming and expensive
Solution Approach 1:
The impeller is segmented into a stationary part and a movable seal ring. The seal ring can be independently adjusted relative to the impeller body without moving the entire impeller, allowing clearance adjustment while the pump remains assembled and reducing downtime.
Solution Approach 2:
The seal ring is made adjustable and movable relative to the impeller body through threaded apertures and adjusting screws. This dynamic component allows real-time clearance adjustment without shutting down the pump, transforming a static clearance into a dynamically adjustable one.
2Reliability
If the seal ring is adjusted too far towards the impeller, then the sealing improves, but the screw can rub the impeller and increase wear
Solution Approach 1:
The seal ring has different functional zones: an outer peripheral surface that contacts the impeller for sealing, and an inner peripheral surface with threaded apertures for adjustment. The raised intermediate portion creates a mechanical stop that prevents over-adjustment, ensuring the sealing surface approaches the impeller without causing damage through excessive contact.
3Manufacturing precision
If conventional adjustment methods are used, then the clearance can be modified, but the adjustment is not precise and the risk of screw damage is higher
Solution Approach 1:
The raised intermediate portion is pre-formed on the adjusting screw to act as a mechanical stop before the screw can contact the impeller. This preliminary protective feature prevents over-tightening and potential screw damage before it occurs, allowing operators to achieve precise clearance without risking component failure.
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
This solution provides a user-friendly method to adjust the impeller/ring clearance, reducing wear and slurry recirculation, enhancing pump efficiency and extending the life of expensive pump components by allowing for finer adjustments and minimizing the risk of screw damage.
Implementation Method 1
a seal member configured with at least two threaded apertures; at least two adjusting screws... each adjusting screw may also be configured to be rotated in one rotational direction and moved in one axial direction
Data Source
AI summary
In a pump arrangement, each adjusting screw has first and second end portions, a third intermediate raised portion, and a fourth portion to allow each adjusting screw to be rotated clockwise/counterclockwise. Each first end portion passes through a suction liner aperture so left-handed threads couple to a respective left-handed seal ring aperture. Each second portion passes through a suction half casing aperture so the fourth portion can be accessed to allow clockwise/counterclockwise rotation of each adjusting screw. Each adjusting screw rotates clockwise and moves until the third portion pushes against the suction half casing, so the screw stops moving and the seal ring moves away from the suction liner as the screw is rotated clockwise, or rotates counterclockwise and moves until the third portion pushes against the suction liner, so the screw stops moving and the seal ring moves towards the suction liner as the screw is rotated counterclockwise.