Cart-Based Lance Cleaning System for Heat Exchanger Tubes
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Solution Overview
Problem
Existing methods for cleaning heat exchanger tubes using high-pressure water lances face challenges such as lance buckling and the hazardous jet reaction from high-pressure fluid discharge, making it difficult to accurately position and operate the lance during cleaning.
Innovation Solution
An apparatus comprising a cart with a lance and pressure sensing device that propels the cart in reverse when a pressure threshold is detected, allowing for controlled movement and safer operation by opening and closing doors to guide the lance into and out of the tubes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high pressure water is forced through the lance at extremely high pressures (in excess of 10,000 psi), then cleaning effectiveness is improved, but jet reaction from the high pressure stream blows backward and strikes the operators guiding the lance
Solution Approach 1:
The patent redirects the harmful jet reaction force backward on the lance into a useful propulsive force that moves the cart forward along the rail. The reaction force that previously struck operators is now harnessed to automatically advance the cleaning apparatus, converting a dangerous byproduct into a beneficial driving mechanism.
2Length of moving object
If the lance is made long to reach deep into elongated tubes, then cleaning reach is improved, but the lance becomes difficult to accurately position and control as it travels on the channel member
Solution Approach 1:
The patent replaces manual mechanical positioning and guidance of the long lance with an automated system. The cart-mounted lance is propelled automatically by the jet reaction force along a predetermined rail path, eliminating the need for operators to manually guide the long, unwieldy lance while maintaining accurate positioning through the constrained rail system.
3Ease of operation
If the lance is supported in an open channel member, then ease of insertion is improved, but the lance is difficult to accurately position as it travels on the channel member
Solution Approach 1:
The patent employs a constrained rail system that provides guided support for the lance while allowing smooth movement. The rail acts as a precision-guided pathway that maintains lateral positioning accuracy while permitting the lance to be propelled forward by the jet reaction force, combining the benefits of open channel access with precise positional control.
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
This solution enhances the safety and accuracy of cleaning elongated tubes by mitigating lance buckling and jet reaction issues, enabling effective removal of debris while maintaining efficient cleaning operations.
Implementation Method 1
a pressure sensing device located in the cart and detecting a pressure exerted on the cart as the cart moves in a forward direction in the rail
Implementation Method 2
The front end (operating end) of each lance is fed into the tube through a vertical separator plate positioned at the front end of the channel member. The drive means comprises a set of motor-driven friction rollers which engage the lances immediately behind the separator plate.
Implementation Method 3
The water pressure in a lance may easily exceed 10,000 psi with flow rates in excess of 100 gallons per minute
Data Source
AI summary
A system and method for cleaning elongated tubes is presented. An apparatus for cleaning elongated tubes includes a cart, a lance, a pressure sensing device and a propulsion device. The lance sprays material into elongated tubes to clean the elongated tubes. The cart supports the lance while the cart is moves in a rail in a forward direction and in a reverse direction. The pressure sensing device is located in the cart detects a pressure exerted on the cart as the cart moves in a forward direction in the rail. The propulsion device, upon the pressure sensing device detecting a pressure crossing a threshold value, propels the cart in the reverse direction for predetermined distance or time before again propelling the first cart in the forward direction.