Gear Pump Flexible Inner Section Resilient Sealing
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Solution Overview
Problem
Gear pumps used in bioprocessing applications face a challenge in balancing high efficiency with low cost, as close tolerance parts are required for reduced leakage but are costly to produce, while disposable nature of apparatus necessitates low-cost components.
Innovation Solution
A gear pump design featuring gear elements with a rigid outer portion and a flexible inner section, providing resilient sliding contact with the housing to minimize back leakage and maintain efficiency without increasing drive torque, using materials like elastomeric bosses and flexible plastics for reduced cost and improved wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If close tolerance parts are used to reduce leakage, then pump efficiency is improved, but manufacturing cost increases
Solution Approach 1:
The gear elements change their clearance parameters dynamically during operation. At low pressure, larger clearances reduce friction and allow easier manufacturing. At high pressure, the flexible inner section causes the teeth to deflect inward, automatically reducing the clearance to minimize back leakage. This parameter change resolves the contradiction between manufacturing cost and energy loss.
Solution Approach 2:
The gear elements transition from a static clearance design to a dynamic one where the clearance varies with operating pressure. The flexible inner section enables the teeth to move radially inward under pressure, automatically adjusting the clearance to maintain sealing efficiency without requiring precision manufacturing tolerances.
2Reliability
If rigid parts are used to maintain close tolerance under pressure, then service life is improved, but manufacturing cost increases
Solution Approach 1:
The gear elements change their structural parameters by utilizing the flexibility of the inner section under pressure. Instead of relying on rigid precision-machined parts, the design allows controlled elastic deformation of the inner section that maintains sealing contact with the housing, achieving reliable sealing with cheaper, less precisely manufactured components.
Solution Approach 2:
The gear elements combine a rigid outer portion (for structural strength and tooth geometry) with a flexible inner section (for automatic clearance adjustment). This composite structure achieves both durability and cost-effectiveness by allowing the cheaper flexible material to perform the critical sealing function under pressure.
3Ease of operation
If clearances are increased to reduce friction, then ease of operation is improved, but pump efficiency deteriorates
Solution Approach 1:
The clearance between gear teeth and housing is dynamic rather than static. At low pressure, larger clearances reduce friction and ease operation. As pressure increases, the flexible inner section deflects the teeth inward, automatically reducing the clearance to prevent excessive leakage. This dynamic adjustment resolves the contradiction between ease of operation and pump efficiency.
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 design achieves high efficiency with reduced back leakage and maintains operational reliability across a wide range of fluid flow rates and pressures, suitable for disposable small-scale bioprocessing applications, while being cost-effective.
Implementation Method 1
an inner relatively more flexible section between the outer portion and a centre of rotation of the or each gear element
Data Source
AI summary
Disclosed is a gear pump (10) comprising a contra rotating gear element pair (30 and 40) mounted within a housing (20), each gear element having complementary gear teeth sets providing a pumping action in use, said teeth being formed from an annulus (34 and 44) of generally rigid construction mounted on a relatively flexible inner section (35 and 45), the gear pair being mounted such that their respective annuli are biased into resilient contact with the housing to provide a sliding seal.