Gravity-Actuated Nuclear Pit Gate Sealing Mechanism

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Solution Overview

Problem

Conventional pool gates in nuclear power facilities require pressurization to maintain sealing, which is not effective without a pressure source, leading to decreased sealing performance due to reduced contact between the packing and the wall surface under initial conditions without water pressure.

Innovation Solution

A pit gate with a simple structure that includes a gate main body, a sealing member, and a pressing clamp system, where the gate main body is moved towards the sealing member by its own weight, ensuring watertight sealing without the need for external pressurization, utilizing wedge-shaped pressing members to maintain contact with the slot.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pressure source is used to pressurize the packing, then the sealing function is ensured, but the device complexity increases and a pressure source is needed

Engineering Contradiction:
Improvesealing functionVSAvoidpressure source requirement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The gate body itself serves as the pressing means by utilizing its own weight to pressurize the packing. The gate body is designed with an inclined pressing surface that converts gravitational force into pressing force on the packing, eliminating the need for external pressure sources while maintaining reliable sealing function.

Inventive Principle:
Principle #25Self-service

2Device complexity

If no pressure source is used, then the device complexity is reduced, but the contact property between packing and wall surface decreases leading to poor sealing

Engineering Contradiction:
Improvestructure simplicityVSAvoidsealing property
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The gate body is designed with a built-in pressing mechanism that automatically pressurizes the packing as soon as the gate is installed in the slot. The inclined pressing surface ensures that the gate body's weight immediately generates pressing force on the packing upon installation, establishing good contact property and sealing performance before any water pressure is applied.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The pressing force on the packing is changed from being pressure-source-dependent to gravity-dependent. By designing the gate body with an inclined pressing surface, the system converts the constant gravitational parameter into a useful pressing force that maintains consistent contact between the packing and the slot wall surface.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If the gate body weight is used for pressurization, then no pressure source is needed, but the pressing force may be insufficient without proper structural design

Engineering Contradiction:
Improvepressure source eliminationVSAvoidpressing force
Core Design Contradiction:
Device complexityVSForce

Solution Approach 1:

The gate body incorporates an inclined pressing surface that acts as a mechanical advantage element. This inclined surface converts the vertical gravitational force into a horizontal pressing force on the packing, effectively amplifying the pressing force generated by the gate body's weight and ensuring sufficient contact pressure for reliable sealing.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 pit gate effectively seals service water in a watertight manner, suppressing leakage and maintaining sealing performance even without external pressurization, ensuring reliable operation in nuclear power facilities.

Implementation Method 1

a pressing clamp that is provided in the gate main body and that moves the gate main body toward the sealing member side due to a weight of the gate main body itself

Methodology Applied
Scientific EffectGravitation: Gravitation

Implementation Method 2

the second slot-side pressing member is formed in a wedge shape whose thickness becomes greater from the upper side toward the lower side in the vertical direction, so that a second slot-side inclined surface that is inclined toward the sealing member side

Methodology Applied
Scientific EffectWedge: Wedge

Data Source

PatentEP3023993B1Pit gate, pit equipment, nuclear power facility, and installation method of pit gate
Publication Date: 2017.08.23 MITSUBISHI HEAVY IND LTD
  • EP3023993B1 patent drawingFigure 1
  • EP3023993B1 patent drawingFigure 2
  • EP3023993B1 patent drawingFigure 3

AI summary

A pit gate (15) that is accommodated in a slot (14) and that seals service water retained in a first pit and a second pit in a watertight manner includes a gate main body (21); a sealing member (22) that is provided on a surface opposite to the slot (14) in a gate main body (21) and that seals between the gate main body (21) and the slot (14) in a watertight manner; and an upper pressing clamp (23), an intermediate pressing clamp (24), and a lower pressing clamp (25) that are provided in the gate main body (21) and that moves gate main body (21) toward the sealing member (22) side due to the weight of the gate main body (21) itself.