Valve Actuator Torque Limiting Coupling for Overload Protection

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Solution Overview

Problem

Actuated valve assemblies face issues with excessive torque transfer, which can lead to damage of valve elements, shafts, and actuators due to stuck or over-pressured valve elements.

Innovation Solution

A torque limiting coupling assembly is introduced, which is positioned between the valve shaft and the actuator. This assembly decouples the rotation of the valve shaft from the actuator's rotation when excessive resistance is encountered, translating the applied torque into a linear force to compress a bias element rather than forcing rotation against resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the actuator is directly coupled to the valve shaft, then the torque transfer is efficient and reliable, but the valve assembly becomes vulnerable to damage from excessive torque

Engineering Contradiction:
Improvetorque transfer reliabilityVSAvoidexcessive torque damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A torque limiting coupling assembly is introduced as an intermediary component between the actuator and valve shaft. This assembly includes a coupling body with a drive shaft, torque limiting mechanism, and disengagement mechanism that prevents excessive torque from reaching the valve shaft while maintaining reliable torque transfer during normal operation

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The torque limiting coupling assembly incorporates a torque limiting mechanism that预先 sets a maximum torque threshold. When torque exceeds this threshold, the mechanism automatically engages to limit or disengage the torque transmission, protecting the valve shaft and valve element from damage before excessive torque can cause harm

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Ease of operation

If the actuator applies high torque to move the valve element, then the valve element can overcome resistance and reach the desired position, but the valve shaft and actuator may be damaged by excessive counter-torque

Engineering Contradiction:
Improvevalve element movement capabilityVSAvoidvalve shaft strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The torque limiting coupling assembly serves as a mediator that allows the actuator to apply high torque when needed to move the valve element against resistance, while simultaneously protecting the valve shaft from excessive counter-torque through its torque limiting and disengagement mechanisms

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The coupling assembly dynamically adjusts the torque transmission based on operating conditions. During normal operation, it transmits torque efficiently to move the valve element. When counter-torque exceeds the torque limit, the disengagement mechanism activates to decouple the actuator from the valve shaft, preventing damage while maintaining operational capability

Inventive Principle:
Principle #15Dynamics

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 torque limiting coupling assembly effectively shields the valve assembly from excessive torque, preventing damage to the valve elements, shafts, and actuators while maintaining the ability to move the valve element to the desired position.

Implementation Method 1

a bias element extending between the collar and sleeve to bias the sleeve distally so that the two radially inward facing distal bosses are normally in the distal closed end of the respective helical groove

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4495447A1A torque limiter for valve actuators
Publication Date: 2025.01.22 WATTS REGULATOR CO
  • EP4495447A1 patent drawingFigure 1
  • EP4495447A1 patent drawingFigure 2
  • EP4495447A1 patent drawingFigure 3

AI summary

A torque limiting coupling assembly shields a valve actuator from abnormally high levels of torque. In normal operation, an actuator coupling transfers a driving torque from an actuator coupling to a valve shaft coupling and the valve shaft coupling engenders a shaft torque on a shaft of a valve. In torque actuated operation, when a counter torque applied to the shaft coupling exceeds a threshold value, the actuator coupling freely rotates relative to the valve shaft coupling and the driving torque is transferred to a biasing element of the torque limiting coupling assembly rather than to the valve shaft coupling, thereby shielding the valve or the actuator from high levels of torque.