Piston Pilot Valve Actuator for Wider Setpoints and Lower Leakage

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Solution Overview

Problem

Existing pilot valve actuators face issues with precision and remote control due to diaphragm cracking, limited range of setpoints, and significant leakage through flexible hoses, leading to inefficiencies and reliability concerns.

Innovation Solution

An actuator design featuring a piston within a housing defines an actuator chamber, where fluid pressure controls the compression of a loading spring, enabling a wider range of setpoints and improved reliability by eliminating diaphragm cracking and reducing leakage through integrated solenoid valves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an actuator diaphragm is used to transmit control pressure to the loading spring, then the setpoint can be controlled, but the diaphragm is prone to cracking which reduces reliability and causes leakage

Engineering Contradiction:
Improveactuator reliabilityVSAvoiddiaphragm cracking and leakage
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent removes the actuator diaphragm from the system entirely, replacing it with a piston that directly transmits control pressure to the loading spring. This extraction eliminates the cracking and leakage problems associated with diaphragms while maintaining the setpoint control function.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the flexible diaphragm mechanism with a rigid piston mechanism. The piston provides a more reliable mechanical connection that eliminates the harmful cracking and leakage effects while maintaining the ability to transmit control pressure for setpoint adjustment.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If a flexible hose is used to connect the control fluid source to the diaphragm, then remote control is enabled, but significant leakage and pressure loss occur

Engineering Contradiction:
Improveremote control capabilityVSAvoidpressure loss and leakage
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent removes the flexible hose from the control fluid path by integrating the solenoid valves directly into the housing. This extraction eliminates the leakage and pressure loss associated with flexible hoses while maintaining remote control capability through the integrated valve system.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the solenoid valves with the housing structure, eliminating the need for separate flexible hose connections. This integration reduces leakage paths and pressure losses while preserving the ability to control the pilot valve remotely.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If an actuator diaphragm with pin arrangement is used, then the loading spring can be compressed, but the limited travel restricts the range of setpoints

Engineering Contradiction:
Improverange of setpointsVSAvoidactuator travel distance
Core Design Contradiction:
Adaptability or versatilityVSLength of moving object

Solution Approach 1:

The patent replaces the limited-travel diaphragm-pin mechanism with a piston that has greater travel capability. The piston can move further to compress the loading spring over a wider range, enabling adjustment of a broader range of setpoints while providing more precise control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 piston-based actuator provides a more sensitive and reliable control of pilot valve setpoints, achieving a wider range of pressures and reducing power consumption and operational lifetime of valves, while minimizing leaks and maintaining control pressure.

Implementation Method 1

The chamber is fluidly connected to a control fluid feed that allows the fluid pressure within the chamber to be selectively controlled. The fluid pressure acts on the piston against the bias of the loading spring.

Methodology Applied
Scientific EffectFluid pressure: Pressure Increase

Implementation Method 2

The setpoint of the pilot valve is controlled by controlling the compression of a loading spring, which extends between a piston and an actuation member, to exert a biasing force on the actuation member.

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP3980857B1Actuator for a pilot valve
Publication Date: 2023.05.17 OFIP LTD
  • EP3980857B1 patent drawingFigure 1
  • EP3980857B1 patent drawingFigure 2
  • EP3980857B1 patent drawingFigure 3

AI summary

An actuator (1) for a pilot valve (26), including a housing (2), a piston (4) movably mounted in the housing (2) and an actuator chamber (20) defined between the piston (4) and the housing (2). The actuator (1) includes a control fluid feed (16) for introducing a fluid into the actuator chamber (20) to control fluid pressure, with the fluid pressure acting on the piston (4). The actuator (1) also includes an actuation member for acting on the pilot valve (26) and a loading spring (6) between the piston (4) and the actuation member. The loading spring (6) is arranged to bias the piston (4) against the fluid pressure in the actuator chamber (20). The control fluid feed (16) controls the fluid pressure so the fluid pressure acts on the piston (4) against the bias of the loading spring (6) to control the biasing force.