Pressure Switch Piston Limiter for Over-Travel Protection
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Solution Overview
Problem
Existing pressure switch designs can suffer from over-travel of the actuator, leading to potential damage or breakage of the switching component due to high fluid pressure rise rates, which existing limiter mechanisms fail to prevent effectively.
Innovation Solution
The pressure switch incorporates an actuation unit with a radially extending limiter and a hollow cavity, along with a seal arrangement and spring stop region, to prevent over-travel by engaging a stationary insert and limiting further movement when the actuation unit transitions to the pressurized position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional limiter member is used to restrict piston travel, then the piston movement is limited, but the actuator can still over-travel and damage the switching component due to high fluid pressure rise rates
Solution Approach 1:
The patent combines the limiter function directly into the actuation unit by creating an enlarged cross-sectional region that engages with the stationary insert. This integration eliminates the need for a separate limiter member, achieving reliable over-travel protection while reducing device complexity. The actuation unit itself becomes the limiting mechanism through its geometric design.
Solution Approach 2:
The stationary insert acts as an intermediary element between the actuation unit and the switching component. When the actuation unit reaches its predetermined travel distance, the enlarged cross-sectional region engages with the stationary insert, which mediates the stopping action. This intermediary mechanism provides reliable protection against over-travel damage while maintaining a simple overall structure.
2Ease of operation
If the actuator is allowed to travel freely to actuate the switching component, then the switching operation is effective, but the actuator can launch towards the switching component with excessive velocity causing damage
Solution Approach 1:
The patent implements preliminary action by pre-configuring the actuation unit with an enlarged cross-sectional region at a specific position along its travel path. This geometric feature is designed in advance to engage with the stationary insert before excessive velocity can cause damage. The limiter action is built into the structure itself, ensuring that the actuator can travel freely within safe limits but is automatically restrained if it approaches dangerous velocities.
3Power
If a separate piston and actuator design is used, then the pressure transmission is effective, but the actuator can separate from the piston during high pressure rise rates causing uncontrolled travel
Solution Approach 1:
The patent merges the piston and actuator functions into a single integrated actuation unit. This unified design ensures that the pressure transmission path remains intact and the actuator cannot separate from the piston during high pressure rise rates. The integrated structure maintains reliable connection stability while preserving effective pressure transmission to actuate the switching component.
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 effectively safeguards against over-travel of the actuator, preventing damage to the switching component by ensuring the actuation unit cannot exceed a predetermined displacement, thereby enhancing the reliability and durability of the pressure switch.
Implementation Method 1
The actuation unit is biased in a first direction D1 along the axis A by a spring arrangement 110 of one or more spring members
Implementation Method 2
The actuation unit moves along the axis A towards the actuator 104 when fluid enters a switch body 112 through a fitting end 114 from a conduit
Data Source
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AI summary
A pressure switch includes an actuation unit disposed within a body of the pressure switch and biased in a first direction by a spring arrangement and accessible at a fitting end of the pressure switch to be movable in a second direction against the bias of the spring by fluid at the fitting end. The actuation unit includes a limiter trapped in a pocket to limit the range of travel of the actuation unit, thereby safeguarding the electrical switch element from sustaining damage due to excessive travel. The pocket may be formed by the cooperation of two separate pieces. The spring arrangement may be biased by another piece disposed within a body of the pressure switch.