Submerged Pump Reservoir with Bleed and Recirculation Paths
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Solution Overview
Problem
The existing systems for supplying isocyanate liquid in foam-in-bag or foam-in-place packaging require difficult and messy pump changeover processes when switching from an empty to a full supply container, as the pump must be lifted out of the empty container, potentially exposing it to ambient moisture and leading to reaction with isocyanates.
Innovation Solution
A system with a reservoir tank, pump, bleed path, and recirculation path allows the pump to remain submerged within the liquid, using a bleed path to maintain the liquid level above the low point and a recirculation path to maintain it below the high point, along with a siphon tube assembly that includes a drip cup to minimize liquid exposure during changeover, enabling the pump to remain submerged and reducing drips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pump is submerged in the supply container to ensure sufficient suction pressure head and minimize liquid leakage reaction with ambient moisture, then the pump reliability is improved, but the pump changeover process becomes difficult and messy when withdrawing the pump from an empty container
Solution Approach 1:
The system is divided into two separate containers: a supply container for storing liquid and a reservoir tank for holding the pump and maintaining liquid level. This segmentation allows the pump to remain submerged in the reservoir tank during changeover, eliminating the need to withdraw it from the empty supply container while maintaining reliable liquid supply through the siphon tube.
Solution Approach 2:
A reservoir tank serves as an intermediary between the supply container and the pump. The reservoir tank maintains a liquid level that keeps the pump submerged, providing a stable environment for the pump during container changes while ensuring continuous liquid supply through the siphon tube to the pump inlet.
2Ease of operation
If the pump is lifted out of the empty container during changeover, then the pump can be installed in the full container, but the pump is exposed to ambient moisture and reacts with isocyanates
Solution Approach 1:
By separating the supply container from the pump housing (reservoir tank), the system allows the pump to remain submerged in liquid within the reservoir tank during changeover operations, preventing exposure to ambient moisture and isocyanate reactions while enabling smooth container exchanges.
Solution Approach 2:
The reservoir tank creates a protected environment with liquid surrounding the pump, effectively creating an inert barrier between the pump and ambient moisture. This protected environment prevents unwanted chemical reactions during the changeover process.
3Reliability
If the liquid level in the reservoir tank is not maintained, then the pump may run dry or overflow, but maintaining the liquid level requires additional control mechanisms
Solution Approach 1:
The system uses the pump's own operation to maintain liquid level in the reservoir tank. When the pump runs, liquid flows from the reservoir through the siphon tube to the pump inlet, and excess liquid automatically drains back through the bleed path, creating a self-regulating level control mechanism without external sensors or actuators.
Solution Approach 2:
The liquid level in the reservoir tank is automatically regulated through feedback from the pump's operational state. The bleed path provides a feedback mechanism where liquid flows back to the reservoir when the level rises, and the siphon tube ensures liquid is drawn when the level drops, creating a self-correcting system.
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 allows for seamless changeover between supply containers without lifting the pump, minimizing exposure to moisture and reducing drips, thus maintaining pump functionality and operational efficiency.
Implementation Method 1
A siphon tube, coupling, and drip cup assembly is used to transfer liquid from the supply container to the reservoir tank
Data Source
AI summary
A system for supplying a liquid. A reservoir tank has a low level and a high level of the liquid. A pump is submerged in the liquid within the reservoir tank. The pump has an inlet to receive the liquid from a source outside of the reservoir tank and an outlet to deliver the liquid to a destination outside of the reservoir tank. A bleed path places the pump outlet in fluid communication with the reservoir tank. The bleed path has a bleed valve controlling the flow of liquid through the bleed path to maintain the liquid level in the reservoir tank above the low level. A recirculation path places the pump inlet in fluid communication with the reservoir tank. The recirculation path has a recirculation valve controlling the flow of liquid through the recirculation path to maintain the liquid level in the reservoir tank below the high level.