Front-Loading Seal Subassembly for Rotary Pump Servicing
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Solution Overview
Problem
Rotary positive displacement pumps face challenges in maintenance and cleanliness due to complex disassembly requirements and 'dead zones' that hinder effective cleaning-in-place processes, leading to increased downtime and sanitation issues.
Innovation Solution
The introduction of a front-loading seal construction and modifications to the pump design, including enlarged axially-extending openings and sliding seal subassemblies, allows for service and cleaning without removing the pump body from the gear case, reducing 'dead zones' and improving fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If the pump body is detached from the gear case to service the seals, then the seals can be accessed and maintained, but the pump experiences long periods of downtime and complex disassembly is required
Solution Approach 1:
The pump is divided into modular components with the seal assembly being a separate, independently serviceable unit. The seal assembly includes a seal carrier and seal elements that can be removed and serviced without detaching the entire pump body from the gear case, enabling maintenance of individual seal components while the pump remains assembled.
Solution Approach 2:
The seal assembly is extracted as a removable component from the pump body. The seal carrier can be detached from the pump body through the drive shaft interface, allowing seal servicing without complete pump disassembly. This extraction principle enables access to seals while maintaining the overall pump assembly integrity.
2Ease of manufacture
If the pump body is removed from the gear case to clean internal components, then thorough cleaning is possible, but complex disassembly and reassembly is required
Solution Approach 1:
The pump internal components are segmented into independently accessible modules. The seal assembly and other internal components can be accessed and cleaned through openings in the pump body without removing the entire pump body from the gear case, simplifying the cleaning process while maintaining structural integrity.
Solution Approach 2:
The pump design incorporates preliminary cleaning features such as accessible openings and smooth surfaces that prevent material buildup before cleaning is needed. The enlarged openings and eliminated dead zones are built-in features that facilitate easy cleaning without requiring complex disassembly procedures.
3Device complexity
If traditional seal arrangements are used between the gear case and pump body, then the pump structure is simple, but the seals cannot be serviced without removing the pump body
Solution Approach 1:
The seal system is segmented into a modular seal assembly that includes the seal carrier, seal elements, and associated components. This seal assembly can be independently removed and serviced through the drive shaft interface without detaching the pump body from the gear case, providing easy seal maintenance while maintaining a relatively simple overall structure.
Solution Approach 2:
The seal carrier acts as an intermediary component between the pump body and the seals. It provides a interface through which seals can be accessed and serviced. The seal carrier can be removed through the drive shaft opening, serving as a mediator that enables seal maintenance without requiring pump body removal.
4Device complexity
If the pump has dead zones in the cavity, then the pump structure is simple, but cleaning-in-place processes are ineffective as fluid cannot reach these areas
Solution Approach 1:
Dead zones are eliminated by redesigning the pump cavity to remove recesses and corners where fluid could stagnate. The cavity is extracted of unnecessary geometric complexity, creating smooth, continuous surfaces that allow cleaning fluid to reach all areas. This simplification maintains structural integrity while dramatically improving cleanability.
Solution Approach 2:
The pump cavity is designed with uniform, smooth surfaces and optimized geometry that eliminates local areas prone to fluid stagnation. The enlarged openings and streamlined internal passages ensure consistent fluid flow throughout the entire cavity, preventing localized dead zones while maintaining overall structural simplicity.
Data Source
AI summary
A rotary positive displacement pump has a front-loading seal arrangement to better accommodate servicing and cleaning of the pump body. The pump includes a sliding seal subassembly disposed in a volume between a central portion of a rotor that is received on a shaft of a gear case and the hub of the pump body. A related method of modifying a rotary positive displacement pump enables a conventional pump with a rear-side seal arrangement to be transformed into a pump having a front-loading seal arrangement. In addition to the reduction of a dead zone in which turbulent flow does not occur by inclusion of the sliding seal subassembly, other modifications to the pump body improve the ability of the pump to be cleaned in place.