Backflow Prevention Apparatus with Metal Check Valve for Fire Safety
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Solution Overview
Problem
Float-type backflow prevention valves in wastewater drainage systems fail to control the flow of air and gas, allowing gases such as those produced at drainage basins or smoke from fires to flow back into buildings, and do not maintain valve closure during fires, risking damage to the float.
Innovation Solution
A backflow prevention apparatus comprising a check valve and a float-type backflow prevention valve, where the check valve is installed upstream and includes a metal valve seat, valve member, and restoring force exerting member to prevent gas movement and maintain closure during fires, while the float-type valve controls wastewater flow to prevent backflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a float-type backflow prevention valve is used to prevent wastewater backflow, then backflow prevention is achieved, but gas flow control is lost allowing gases to flow back into buildings
Solution Approach 1:
The backflow prevention system is divided into two separate functional valves: a check valve for gas flow control and a float-type backflow prevention valve for wastewater flow control. This segmentation allows each valve to specialize in controlling its respective fluid type, preventing gases from flowing back into buildings while maintaining reliable wastewater backflow prevention.
Solution Approach 2:
The check valve is designed with multi-functionality to serve dual purposes: it prevents gas flow back into buildings during normal operation and maintains valve closure during fires to prevent float damage. This universal component addresses both gas flow control and fire safety requirements within a single valve design.
2Reliability
If the check valve components are made from metal, then valve closure is maintained during fires, but manufacturing complexity increases
Solution Approach 1:
Metal material is applied selectively only to the critical components of the check valve that require fire resistance (valve seat, valve member, and restoring force exerting member), while other non-critical parts of the system can use less expensive materials. This local quality approach maintains reliable valve closure during fires without unnecessarily increasing overall manufacturing complexity.
3Object-generated harmful factors
If the float is exposed to high temperatures during fires, then gas flow prevention is maintained, but the float may be damaged
Solution Approach 1:
The check valve acts as an intermediary protective barrier between the float and the harmful high-temperature fire environment. During fires, the check valve maintains closure to prevent gas flow while also shielding the float from direct exposure to high temperatures, thereby protecting the float's structural integrity.
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
Effectively prevents backflow of wastewater and gas movement, maintaining drainage functionality and preventing damage to the float by ensuring valve closure during fires and gas flow events.
Implementation Method 1
a restoring force exerting member that exerts an upwardly directed restoring force on the valve member
Implementation Method 2
a hydraulic head of wastewater flowing thereinto from a location upstream therefrom
Implementation Method 3
a float that is disposed below the annular valve seat, that rises in accompaniment to a rise in a water level of wastewater and engages with the opening and closes the opening to close the valve at the annular valve seat
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A backflow prevention apparatus 1 is provided with a check valve 10 and a float-type backflow prevention valve 20, these being installed in this order as one proceeds from upstream to downstream. The check valve 10 comprises a valve seat 15 that causes a location toward the float-type backflow prevention valve 20 and a location upstream therefrom in a wastewater drainage system to be placed in mutual communication; a valve member 14 that closes the valve at the valve seat 15 due to an upwardly directed restoring force and that opens the valve at the valve seat 15 as a result of being made to fall when the restoring force is overcome by a hydraulic head of wastewater flowing thereinto from a location upstream therefrom; and a restoring force exerting means 13 that exerts an upwardly directed restoring force on the valve member 14; wherein the components responsible for causing closure of the valve at the valve seat 15 by the valve member 14-which include the valve seat 15, the valve member 14, and the restoring force exerting means 13-are formed from metal(s). The float-type backflow prevention valve 20 comprises an annular valve seat 21 that causes a location downstream therefrom in the wastewater drainage system and a location toward the check valve 10 to be placed in mutual communication; a float 24 that rises in accompaniment to a rise in a water level of wastewater to close the valve at the annular valve seat 21 and that falls in accompaniment to a fall in a water level of wastewater to open the valve at the annular valve seat 21; a guide member 22 that guides movement of the float 24 in a vertical direction; and a constraining member 23 that constrains a lowermost position to which the float 24 can move.