Bag-in-Keg Pressure Relief Valve With Fixed Bag Venting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In bag-in-keg containers, existing pressure relief valves fail to effectively manage internal pressure within the flexible bag, leading to over-pressure situations due to the pressure differential between the bag and the outer container, which can result in excessive venting and loss of carbonation when trying to dispense carbonated beverages.
Innovation Solution
A pressure relief valve system comprising a bag PRV with a sealed plenum chamber and a shuttle mechanism that vents gas pressure from the flexible bag into a dispensing gas space between the container body and the bag, independent of the pressure differential, ensuring the bag PRV operates at a fixed pressure and maintains carbonation levels by preventing pressure rise in the dispensing gas space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure relief valve is configured to open with a pressure difference of 5 bar, then the internal bag pressure can be relieved when it rises above 5 bar, but the pressure between the bag and the keg rises and the internal bag pressure at which the PRV opens rises by the same amount, resulting in maximum internal pressure of 10 bar which is not acceptable
Solution Approach 1:
A sealed plenum chamber is introduced as an intermediary between the bag PRV and the dispensing gas space. The plenum chamber receives vented gas from the bag but seals it off from directly pressurizing the dispensing gas space, thereby mediating the pressure transfer and preventing the cumulative pressure effect that would otherwise occur
Solution Approach 2:
The pressure relief system is segmented into distinct functional zones: the bag interior, the plenum chamber, and the dispensing gas space. This segmentation allows independent pressure control in each zone, enabling the bag PRV to operate at its set pressure without directly affecting the dispensing gas space pressure
2Stress or pressure
If the bag PRV vents into the gas space between the bag and the keg, then internal pressure can be relieved, but the pressure in the dispensing gas space rises and carbonation is compromised
Solution Approach 1:
The plenum chamber serves as an intermediary that captures vented gas from the bag and isolates it from the dispensing gas space, preventing direct pressure transfer that would compromise carbonation while still achieving pressure relief from the bag
Solution Approach 2:
The plenum chamber creates a controlled, isolated environment for the vented gas that prevents it from interfering with the carbonation-maintaining atmosphere in the dispensing gas space, effectively treating the plenum as an inert zone for pressure management
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 solution effectively limits the maximum internal pressure to a predetermined level, preventing over-pressure while maintaining the required dispensing pressure for carbonated beverages, ensuring efficient and safe dispensing without compromising carbonation.
Implementation Method 1
A pressure relief valve works due to a pressure difference across it. Therefore, if the additional pressure relief valve is configured to open with a pressure difference of say 5 bar, it will open when the internal bag pressure rises above 5 bar and the pressure between the bag and the keg is 0 bar.
Implementation Method 2
Depending on the type of valve closure, various spring-loaded valve arrangements are provided to sealably close the gas inlet and liquid dispensing ports before the product is dispensed.
Data Source
Figure 1
Figure 2
Figure 3~6
AI summary
A bag-in-keg container for a carbonated beverage has a container body C, a flexible bag B within the container body, and a valve closure V attached to the container body. The valve closure includes a gas inlet port (11), a liquid dispensing port (12), and a spring-loaded valve member (6) to sealably close the gas inlet and liquid dispensing ports. An adapter (20) sealingly attached to the flexible bag B incorporates a bag PRV (26) to vent gas pressure from within the flexible bag. A container PRV (40) vents gas pressure from between the container body C and the flexible bag B. The bag PRV has a valve shuttle with one side exposed to gas pressure within the flexible bag B and an opposite side exposed to gas pressure within a sealed plenum chamber (37). The bag PRV therefore operates at a fixed pressure independent of the differential pressure between the bag and the outer container. This solves the problem of venting excess pressure within the keg whilst still allowing the dispensing gas to achieve the equilibrium