Pump Housing Expansion Joint for Freeze Damage Prevention
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Solution Overview
Problem
Conventional pumps operating in a primed condition are vulnerable to pressure damage due to freeze-expansion of liquids, as they lack the ability to accommodate volume changes caused by freezing, leading to potential damage and leaks.
Innovation Solution
The pump housing is designed to automatically expand and provide additional hydraulic space in response to pressure increases, either through movable pressure-boundary walls or an internal pressure-absorbing member, allowing for volumetric compensation without external leaks or loss of prime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pump operates in a primed condition with fixed internal volume, then pumping efficiency is improved, but the pump becomes vulnerable to pressure damage during freezing events
Solution Approach 1:
The pump housing incorporates a movable pressure-boundary wall that can dynamically adjust the internal volume of the pump head. This dynamic structure allows the housing to expand and contract in response to pressure changes, accommodating freeze-expansion while maintaining the primed condition during normal operation, thus resolving the contradiction between pumping efficiency and pressure damage resistance
Solution Approach 2:
The invention changes the physical parameter of internal volume from fixed to variable. By enabling the pressure-boundary wall to move and alter the internal volume of the pump head, the system can accommodate volume expansion during freezing events without compromising the primed operational state, thereby maintaining both productivity and reliability
2Reliability
If anti-freeze is added to the liquid to prevent freezing, then freeze protection is improved, but the liquid composition and other important properties are altered
Solution Approach 1:
The invention extracts the freeze protection function from the liquid itself and relocates it to the pump housing structure. Instead of modifying the liquid composition with anti-freeze agents, the movable pressure-boundary wall provides mechanical accommodation for freeze-expansion, thereby protecting the liquid composition while still preventing freeze damage
Solution Approach 2:
The movable pressure-boundary wall acts as an intermediary between the liquid and the external environment. It absorbs the stress of freeze-expansion through its movement, preventing the need to alter the liquid composition with anti-freeze additives, thus maintaining liquid stability while providing freeze protection
3Strength
If the pump housing is made rigid to maintain structural integrity, then strength is improved, but the ability to accommodate volume changes during pressure fluctuations is reduced
Solution Approach 1:
The pump housing is segmented into fixed portions and a movable pressure-boundary wall portion. This segmentation allows most of the housing to maintain rigid structural integrity while the specific movable portion provides the necessary compliance to accommodate volume changes during pressure fluctuations and freezing events
Solution Approach 2:
The invention applies local quality by making only the pressure-boundary wall movable while keeping the rest of the housing rigid. This localized mobility provides volume change accommodation exactly where needed (at the pressure boundary) while maintaining overall structural integrity of the pump housing
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 effectively reduces internal pressure during freezing events and pressure fluctuations, preventing damage to the pump and maintaining its operational integrity by providing a passive and reversible expansion mechanism.
Implementation Method 1
The pressure-absorbing member has a compliant property to exhibit a volumetric compression when subjected to a pressure increase in the fluid contacting the pressure-absorbing member
Implementation Method 2
A property that is characteristic of water and most aqueous solutions is that they tend to expand as they undergo a phase change from liquid to solid (ice)
Data Source
Figure 1~3
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Figure 6~7
AI summary
A fluid pump having a pump housing that includes at least one expansion joint, provides volume compensation, as needed, to adjust for changes in pressure in the pump housing. Various embodiments automatically and passively reduce static pressure in the pump housing associated with a freezing event, thereby preventing damage to the pump head. Volume compensation is achieved by employing, in each expansion joint, a dynamic seal that allows relative movement of two portions of the pump housing, and a bias that provides a selected counter-force to the movement of the housing portions. The subject pumps are particularly suited for use in automotive and other rugged applications, in which fluid pumps may experience recurring freezing events.