Frost-proof sanitary fitting with dual backflow preventers
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Solution Overview
Problem
Existing frost-proof outlet fittings do not provide sufficient protection against contamination and freezing, particularly in cold temperatures, as they lack effective mechanisms for automatic drainage and aeration to prevent water from accumulating and freezing within the fitting.
Innovation Solution
Incorporating an inlet-side non-return valve designed as a system separator within the outlet housing, which automatically empties and aerates the area between the two non-return valves, ensuring no liquid column remains inside the fitting, and a drainage valve actuated by the spindle to prevent water accumulation, along with an aeration element that opens after shut-off to allow water to drain via a bypass channel and ventilation element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an inlet-side backflow preventer is provided in the valve housing to prevent water from being forced back into the supply line, then protection against contamination of the supply line is improved, but water may accumulate in the fitting and freeze in cold temperatures
Solution Approach 1:
The patent extracts water from the fitting interior by providing a drainage path that leads from the interior space past the backflow preventers to the exterior environment. This allows accumulated water to be removed while maintaining the backflow prevention function, thereby preventing freezing without compromising contamination protection.
Solution Approach 2:
The drainage path is pre-configured within the fitting structure, allowing water to be removed before freezing conditions occur. The aeration opening also provides preliminary ventilation to facilitate water removal and prevent ice formation in advance of problematic temperature conditions.
2Reliability
If the area between the two backflow preventers is emptied and vented to increase protection against contamination, then reliability is improved, but the device complexity increases due to additional drainage and aeration mechanisms
Solution Approach 1:
The drainage path serves multiple functions: it removes water to prevent freezing, provides a controlled drainage mechanism, and works in conjunction with the aeration opening to facilitate complete water removal. The aeration opening similarly serves both ventilation and water removal functions, reducing the need for separate dedicated components.
Solution Approach 2:
The patent combines the drainage and aeration functions into the existing backflow preventer structure. The drainage path integrates with the backflow preventer housing, and the aeration opening is positioned to work with the same structural elements, thereby reducing overall device complexity compared to having separate independent drainage and aeration systems.
3Ease of operation
If backflow preventers are designed to operate automatically based on fluid pressure, then ease of operation is improved, but the ability to manually control the shut-off function is reduced
Solution Approach 1:
The patent introduces a manual actuator mechanism that serves as an intermediary between the user and the backflow preventer system. This actuator can override or supplement the automatic pressure-based operation, allowing manual control when needed while preserving the automatic operation for normal conditions. The actuator mechanism mediates between the automatic sensing system and the user's control requirements.
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 configuration enhances security against contamination and freezing by ensuring the fitting is completely drained and aerated, preventing water from freezing and maintaining functionality even in wintry temperatures, thus providing greater protection and reliability.
Implementation Method 1
the inlet-side backflow preventer is designed as a system separator, which, when closing a through-opening between a pre-chamber and a middle chamber of the system separator, inevitably also empties and drains the fluid contained in the middle chamber
Implementation Method 2
a drainage valve is provided which can be positively actuated by actuating the spindle in order to create a passage between the pre-chamber and a drain for water
Implementation Method 3
an aeration element that opens after shut-off to allow water to drain via a bypass channel and ventilation element
Data Source
Figure 1
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Figure 3
AI summary
The present invention relates to a frost-proof outlet fitting comprising a valve housing (10) forming a valve seat (14), an outlet housing (30), an intermediate spindle (70) received in an intermediate pipe (80) connecting the outlet housing (30) to the valve housing (10), the outlet housing (30) being provided with an outlet-side backflow preventer (55) and an inlet-side backflow preventer (47) positioned upstream of the outlet-side backflow preventer (55) in the flow direction. In a secondary aspect, the invention provides a method for shutting off and venting such an outlet fitting. With a view to achieving the simplest possible design and early sealing of the fitting against water entering at the outlet side due to a pressure differential, the inlet-side and outlet-side backflow preventers (47; 55) are arranged in the outlet housing (30).