In industrial settings, repairing or replacing pipe sections and in-line components often necessitates isolating parts of the pipeline, traditionally achieved by draining the system. This process can be costly, time-consuming, and disruptive to production. Huntingdon Fusion Techniques offers an efficient alternative with their Qwik-Freezer® and Accu-Freeze® systems, which enable precise and reliable pipe-freezing to isolate sections without complete drainage.
Qwik-Freezer® System: Ideal for water-carrying pipes up to 200 mm in diameter, this system uses liquid carbon dioxide (CO2) to create a secure ice plug within the pipe, allowing maintenance work with minimal downtime. A case study highlights its application at a power station, where it successfully avoided a costly and time-intensive system shutdown during a valve replacement.
Accu-Freeze® System: Utilizing liquid nitrogen, this advanced system can freeze pipes up to 300 mm in diameter, even under high-pressure conditions of up to 140 bar (2000 psi). The system suits high-stakes environments, including nuclear and aerospace applications. A notable case study demonstrates its critical role in maintaining the Space Shuttle Atlantis, where it allowed for essential repairs without delaying the launch.
These innovative pipe-freezing technologies provide a cost-effective and efficient solution for industrial pipe maintenance, significantly reducing downtime and ensuring minimal disruption to operations. By eliminating the need to drain entire systems, the Qwik-Freezer® and Accu-Freeze® systems offer a practical approach to maintaining productivity while performing essential repairs or modifications.
Low-Cost Accessory Obviates Power Station Shutdown
In the industrial world, repairing or replacing pipe sections or in-line components such as valves and instrumentation often requires isolating sections of pipework. Traditionally, this involves draining the pipeline's contents, which can be solid, liquid, or gaseous. The process does not end there—after repairs or replacements, the system needs to be refilled, leading to interruptions in production and often significant downtime. This traditional method is time-consuming and costly, as it requires the handling, storage, or disposal of the contents.
A more efficient and economical alternative is to freeze the pipe on either side of the repair or replacement zone. By doing so, only the volume of material between the freeze points needs to be emptied, significantly reducing the scope of work and downtime. Two leading solutions are available for this purpose:
Qwik-Freezer® System
The Qwik-Freezer® System is designed for easy and effective use, particularly in water-carrying pipework across various industries, including building services, petrochemicals, food and beverage, hospitals, water treatment, shipping, and aerospace. This system is based on liquid carbon dioxide (CO2) and can be used for pipes up to 200 mm in diameter. The freezing process is straightforward:
This method is safe for use on various pipe materials, including iron, lead, stainless steel, copper, brass, and plastic.
During a new compressor installation at a power station, engineers encountered an unexpected problem—a cold water valve extension handle clashed with the compressor's air inlet pipe. Critically, this was the only isolating valve from the cooling water main header, meaning that moving it would require shutting down the entire cooling water system, effectively bringing the power station to a halt.
Traditional solutions, such as rerouting the inlet pipework or contracting a specialist pipe-freezing company, were considered, but these would have taken significant time and resources, jeopardising the project’s timeline.
Instead, engineers turned to the Qwik-Freezer® System. Although the valve was welded in place, which required freezing the pipe far upstream to avoid heat damage during grinding and re-welding, the Qwik-Freezer® System was ideal for this 75 mm diameter water pipe. Within 24 hours, a kit was sourced, and CO2 bottles were obtained locally. The freeze was successful, taking about an hour, and allowed for the valve replacement within two hours, costing about a quarter of what a specialist contractor would have charged.
Accu-Freeze® System
The Accu-Freeze® System represents the most advanced pipe-freezing technology available today. Using liquid nitrogen, this system offers controlled and automated freezing, creating an in-line ice plug capable of withstanding pressures up to 140 bar (2000 psi) in pipes up to 300 mm in diameter. The Accu-Freeze® System is versatile and can be modified for even larger diameter pipes.
Case Study: Space Shuttle Problem Solved by Pipe Freezing
When the Space Shuttle Atlantis was ready for mission ST-101, a last-minute systems check revealed a fault in the power drive unit (PDU)—a hydraulic pump controlling the shuttle’s rear rudder or air brake. A failure of the PDU during flight could be catastrophic. Conventional repair methods required draining the hydraulic lines, which would have delayed the launch by several weeks and incurred significant costs.
An engineer from United Space Alliance proposed using the Accu-Freeze® System to freeze the hydraulic lines feeding the PDU while the shuttle remained on the launch pad. This approach allowed repairs without draining the system, keeping the launch schedule intact.
The challenge involved freezing six 16 mm hydraulic fluid lines nested in the shuttle's tail, where access was severely restricted. Additionally, the fluid's freezing point was below -100°C, necessitating precise control over the freezing process. After three days of successful trial freezes, the procedure was approved. Despite inclement weather delaying the operation, the Accu-Freeze® System performed flawlessly, holding the freeze in place for over 24 hours and completing the repair successfully.
Conclusions
The pipe freezing technology provided by Huntingdon Fusion Techniques offers a reliable and cost-effective solution for isolating sections of pipework to perform maintenance, repairs, or modifications. By freezing fluids below -150°C using liquid carbon dioxide or nitrogen, this technology eliminates the need to drain entire systems, significantly reducing downtime and disruption to production.
