Flow Path Switching Valve With Pressure Equalizing Sub Valve
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing flow path switching valves for refrigeration cycles face difficulties in smoothly equalizing pressure between the main valve chamber and the sub valve chamber, leading to reduced durability and sealing issues, especially when handling super high-pressure refrigerants like CO2.
Innovation Solution
A flow path switching valve design featuring two pistons joined in a tubular valve housing with a main valve body that slides relative to a valve seat, incorporating a pressure equalizing path and a sub valve to ensure equalization of pressures between the main and sub valve chambers, along with a sloped packing portion to enhance sealing and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a circular slope portion is provided around the packing of the piston to guide refrigerant flow, then the sealing performance is improved, but the pressure equalization between main valve chamber and sub valve chamber becomes difficult
Solution Approach 1:
The invention divides the valve body into distinct functional zones: a first valve body portion with the slope portion for sealing, and a second valve body portion forming a communication passage for pressure equalization. This segmentation allows the sealing function and pressure equalization function to operate independently without interfering with each other, resolving the contradiction between improved sealing and maintained pressure equalization capability
Solution Approach 2:
The communication passage acts as an intermediary channel that allows pressure equalization to occur through a different path that bypasses the slope portion area. This intermediary passage enables pressure balance between chambers while the slope portion maintains its sealing function, eliminating the conflict between these two requirements
2Duration of action of stationary object
If the piston is moved to equalize pressure between main valve chamber and sub valve chamber, then durability is improved, but differential pressure causes stress on packing and reduces reliability
Solution Approach 1:
The invention provides a pressure equalization passage that allows pressure balancing to occur before the piston reaches its final position. This preliminary pressure equalization reduces the differential pressure acting on the packing during the piston movement, preventing excessive stress and maintaining sealing reliability throughout the operation cycle
Solution Approach 2:
The communication passage enables dynamic pressure equalization during piston movement. As the piston moves, pressure can continuously equalize through the passage, adapting to changing pressure conditions and maintaining reliable sealing throughout the dynamic operation, rather than relying on static pressure balance
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 equalizes differential pressures, prevents creep deformation of sealing members, and ensures reliable operation with super high-pressure refrigerants by maintaining pressure balance and reducing stress on piston components.
Implementation Method 1
a pressure equalizing path for communicating the main valve chamber with the sub valve chamber is formed on the axial line corresponding to the sub valve seat, and a sub valve is arranged in the pressure equalizing path for switching open/close of the pressure equalizing path
Implementation Method 2
by introducing a high pressure refrigerant into any one of the two sub valve chambers, and by reducing a pressure of the other sub valve chamber, the piston and the main valve body are moved to the sub valve chamber side due to a differential pressure between the sub valve chamber of which pressure is reduced and the main valve chamber
Implementation Method 3
a sloped portion extending circularly at the center of the valve housing is formed on an outer periphery of the packing. Further, a sectional shape of the sloped portion is gradually closer to an inner wall of the valve housing as the sloped portion extends toward the center of the valve housing
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A pressure equalizing path is provided in the center of the piston 2, and a sub valve 25 is disposed in the pressure equalizing path. When the piston 2 is moved toward a cap 12, the sub valve 25 closes an opening of an exhaust path 12a at a sub valve seat, and opens the pressure equalizing path.