Bolt Heater Junction Housing External Handle Attachment

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Solution Overview

Problem

Existing bolt heaters, particularly those with junction boxes, face issues such as increased assembly time, instability in handle connections, and potential weaknesses in power cable attachments, which hinder efficient heating and fastening processes in applications like steam turbine casings.

Innovation Solution

A bolt heater design featuring a junction housing with enhanced wall thickness for external handle and power cable attachments, allowing for direct and secure external connections without internal components, and a resistance heater rod with non-circular portions for tool-assisted threading, enabling easier assembly and improved stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a standard junction box with thin wall thickness is used, then the device is easier to manufacture, but the handle connection becomes unstable and requires additional internal components for assembly

Engineering Contradiction:

Improveease of manufactureVSAvoidstability of handle connection

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent changes the wall thickness parameter of the junction box from thin (standard) to thick (enhanced), transforming it from a standard hardware box to a custom-designed housing. This parameter change enables direct external threading while maintaining manufacturing feasibility, thereby improving both stability and ease of manufacture simultaneously.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If the handle is secured from the inside of the cover, then the connection can be made, but assembly time increases

Engineering Contradiction:

Improveease of assemblyVSAvoidassembly time

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The patent inverts the traditional assembly approach by moving the handle attachment from internal (inside the cover) to external (outside the housing). This inversion allows the handle to be secured from the exterior through directly accessible threaded openings, eliminating the need for internal assembly operations and significantly reducing assembly time.

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If a separate insert component is used for attaching the power cable, then the cable connection can be made, but assembly time increases and connection reliability decreases

Engineering Contradiction:

Improvereliability of power cable connectionVSAvoidassembly time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent extracts and eliminates the separate insert component from the design. Instead of using an additional insert piece to attach the power cable, the housing is designed with directly integrated threaded openings that accept the power cable attachment hardware. This extraction simplifies the assembly process and eliminates potential failure points while reducing assembly time.

Inventive Principle:

Principle #2Taking out (Extraction)

4Adaptability or versatility

If an adapter piece is used for larger resistance rods, then compatibility is achieved, but additional potential points of weakness are introduced

Engineering Contradiction:

Improveadaptability to different resistance rod sizesVSAvoidreliability of resistance rod connection

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent designs the housing with universally applicable threaded openings that can directly accommodate resistance rods of various sizes. By making the housing itself multi-functional and adaptable, the design eliminates the need for separate adapter pieces, thereby maintaining versatility while improving connection reliability by reducing the number of components and potential failure points.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 improved bolt heater design reduces assembly time, enhances stability, and eliminates potential weaknesses in connections, resulting in a more efficient and reliable heating process for elongating bolts during fastening and unfastening in steam turbine applications.

Implementation Method 1

electrical resistance heater rod

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

the bolt will elongate due to expansion during heating

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS7705272B2Bolt heater assembly unit having junction housing configuration

Publication Date: 2010.04.27 JNT TECHNICAL SERVICES INC

AI summary

A bolt heater including a junction housing, a handle attached and secured to a wall of the housing solely from an exterior of the housing, such as by a threaded connection, a power cable including a fitting attached directly to the wall of the housing, and an electrical resistance heater rod attached to the wall of the housing. The wall may have a boss with a recess therein for receiving a portion of the handle. The housing may be a hollow cylinder with a circular top wall, a circular bottom wall, and a cylindrical side wall. The heater rod may be attached to the housing via a threaded connection and the housing may have a non-circular portion near the threaded connection point, the non-circular portion being engageable by a tool to assist in the threading attachment of the heater rod to the housing.