An outdoor analyser can be warm, powered and healthy while its sample line has stopped delivering water. For UK sites preparing for winter, the exposed route between the process and analyser deserves its own review.
The vulnerable point may be a valve, a connection at the enclosure or a short unprotected section. Start with the complete route and operating conditions before choosing a tubing bundle.
Insulation and heat tracing do different jobs
Insulation reduces heat loss. It does not provide a continuing heat source, so insulation alone cannot be assumed to prevent freezing during a prolonged cold shutdown. Where heat input is required, the design may use electric tracing or a suitable steam-traced arrangement.
PMA’s Dekoron pre-insulated and electrically traced tubing range provides options for instrument and sample lines. The manufacturer’s electric-traced tubing information explains the bundle approach. Selection depends on the installation and the temperature that must be maintained.
Define the winter design case
Use the site’s specified minimum ambient conditions and exposure. Include wind, the route length, elevation changes, the fluid and its required temperature. State whether the line is normally flowing, intermittent or stationary for extended periods.
Start-up and shutdown matter. A system intended to maintain temperature during normal operation may face a different duty after a cold outage. Agree how the sample line will be drained, isolated or returned to service under the site’s procedures, and provide that information with the enquiry.
Review the complete sample route
Freeze protection needs a complete route review, including the connections and periods when flow stops.
Follow the route from end to end
- Mark every exposed connection, valve, junction and enclosure entry.
- Identify supports or penetrations that may create local heat-loss points.
- Check the proposed end seals and protection against water ingress.
- Allow practical access for inspection and replacement.
- Include the final approach to the analyser, not just the longest straight run.
A well-specified bundle can still be undermined by an incomplete installation detail. Review termination requirements and bend limitations against the selected product instructions. Avoid treating different bundle types or tracer arrangements as interchangeable.
Protect measurement quality as well as flow
Maintaining a sample line above freezing does not mean heating every sample to the same temperature. The acceptable temperature depends on the fluid, analytical method and sample integrity. Specify a suitable operating envelope with the analyser supplier.
If the line supplies an ammonia monitoring system or an Aquamonitrix installation, review the transport delay and instrument inlet conditions together with freeze protection. The sample system must support the measurement you intend to make.
What to send for a tubing quotation
Provide a route drawing, line length, tubing material and size, fluid details, design ambient and required maintained temperature. Include utility availability and any hazardous-area classification. Electrical supply, controls and protective arrangements require competent project-specific design.
PMA can review Dekoron options for UK installations, including requirements that call for steam tracing or pre-insulated tubing. A complete route description helps us prepare a quotation that addresses the connections as well as the bundle.
