Rotary Coupling Z-Ring Relief Seal Design

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Solution Overview

Problem

Rotary couplings in the oil and gas industry face reliability and maneuverability issues under severe conditions, particularly in accommodating dynamic pipe expansion and axial rotation while maintaining a secure seal.

Innovation Solution

A rotary coupling design featuring an annular outer section with a Z-ring relief, a connector pipe with a seal end and packing chamber, and a retainer ring with compression screws that compress the Z-ring and packing seals, allowing for adjustable sealing and reduced rotational resistance through a taper-defined packing relief.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If annular sealing or packing rings are used to accommodate dynamic pipe expansion and axial rotation, then the coupling can handle severe conditions, but the reliability and maneuverability become problematic

Engineering Contradiction:
Improveaccommodation of dynamic pipe expansion and axial rotationVSAvoidreliability under severe conditions
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The coupling is divided into distinct functional segments: an outer section for structural support and connection, an inner section for sealing and rotation, and a packing mechanism for maintaining the seal. This segmentation allows each component to be optimized for its specific function while working together to solve the contradiction between adaptability and reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The inner section is designed to rotate relative to the outer section, providing dynamic adaptability to accommodate axial rotation and pipe expansion. The packing rings maintain a reliable seal throughout this dynamic movement, ensuring reliability is maintained even as the coupling adapts to changing conditions.

Inventive Principle:
Principle #15Dynamics

2Ease of manufacture

If traditional rotary coupling designs are used, then connection is achieved, but the coupling is difficult to manipulate and maintain in the field

Engineering Contradiction:
Improveassembly of rotary couplingVSAvoidmaneuverability and maintenance in the field
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The coupling consists of separable outer and inner sections that can be assembled and disassembled independently. The inner section can be removed from the outer section without requiring special tools or complex procedures, making field manipulation and maintenance straightforward while maintaining a secure connection during operation.

Inventive Principle:
Principle #1Segmentation

3Reliability

If packing rings are compressed to maintain seal integrity, then sealing reliability improves, but the rotational resistance increases

Engineering Contradiction:
Improveseal integrityVSAvoidrotational resistance
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The packing rings are positioned and compressed in specific locations within the coupling to maintain seal integrity only where needed. The compression is applied locally at the packing glands rather than uniformly throughout the sealing surfaces, ensuring reliable sealing while minimizing rotational resistance in the rotating components.

Inventive Principle:
Principle #3Local quality

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 design provides a reliable and easy-to-manage rotary coupling that maintains a superior seal under severe conditions, reduces rotational resistance, and accommodates thermal expansion and movement, while allowing for easy adjustment and maintenance.

Implementation Method 1

the compression screws urging a packing end of Z-ring longitudinally against packing seals thereby compressing the packing seals into the packing chamber creating a seal

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

reduces rotational resistance through a taper-defined packing relief

Methodology Applied
Scientific EffectFriction reduction through taper geometry: Friction

Data Source

PatentEP3096059B1Rotary coupling
Publication Date: 2019.07.03 FREUDENBERG OIL & GAS LLC
  • EP3096059B1 patent drawingFigure 1~2
  • EP3096059B1 patent drawingFigure 3
  • EP3096059B1 patent drawingFigure 4

AI summary

Rotary coupling comprising: an annular outer section (102) which includes a female end (118), a threaded portion (122), and a Z-ring relief (109); a connector pipe (104) which includes a connection end (136), a shoulder (138), and a seal end (134) which is inserted into the female end (118) of the outer section (102); a Z-ring (108) housed within the Z-ring relief (109) and packing seals (106) housed within a packing chamber (150); a retainer ring (110) threadably received into the threaded portion (122) of outer section (102), the retainer ring (110) receiving compression screws (112) there-through, wherein in the engaged position the compression screws (112) urging a packing end (144) of Z-ring (108) longitudinally against packing seals (106) thereby compressing the packing seals (106) into the packing chamber (150) creating a seal.