Measuring temperature accurately in a small-diameter pipe is harder than it sounds. A standard thermowell or sensor pocket often won’t fit, and welding one in on site means certified welds and radiographic testing — slow, costly and difficult in hygienic or regulated systems. Kjaerulf Pedersen a/s solves it: the in-line thermowell comes pre-welded into a short pipe section, ready to orbital-weld straight into the line, with a Quick Connect coupling that lets the measuring insert be swapped tool-free.
Why small pipes are a problem
In small-diameter and hygienic pipework there’s rarely room for a conventional thermowell, and compliance rules limit what can be installed and how. Welding a pocket into the line on site brings its own burden: certified welds, radiographic (X-ray) testing and downtime — exactly what a pharmaceutical, biotech or food line can’t afford.
The result is often a compromise on where, or how well, temperature gets measured. A pre-welded, drop-in solution removes that compromise.
The in-line thermowell: Quick Connect
KP’s in-line thermowell integrates a welded thermowell into a short pipe section, delivered fully assembled, pressure tested and polished. It’s built to be orbital-welded directly into small-diameter pipes — so no certified weld or radiographic testing is needed at the installation site. The Quick Connect bayonet coupling then lets the measuring insert be twisted out and back tool-free, keeping process compliance with minimal downtime.
- Sizes from ¼" to DN50, ready for orbital welding
- EN 1.4404 / AISI 316L stainless steel
- Pressure tested to 40 bar, strength tested with the sensor head mounted
- Surface finish < 0.8 µm Ra (mechanically polished)
- Engraved HEAT number for full traceability
- Supplied with 3.1 material certificate, certificate of origin, conformity and surface roughness
- Custom lengths and materials available on request
The in-line thermowell is one part of KP’s Quick Connect program — a modular hygienic sensor platform where the measuring insert can be calibrated or replaced tool-free, without opening the process or stopping production. For a small pipe, that means the pocket goes in once, and the sensor is serviced for the life of the line.
Where it fits
The in-line thermowell suits systems where standard pockets can’t go and integrity matters: pharmaceutical and biotech processing lines, food and beverage, dairy and brewing hygienic pipework, OEM process skids with limited space, and clean-in-place (CIP) / sterilize-in-place (SIP) applications — any regulated environment that needs certified sensor integration without on-site welding headaches.
What engineers ask most
Why can’t a standard thermowell be used in small pipes?
Small-diameter and hygienic pipes rarely have room for a conventional sensor pocket, and compliance rules limit on-site modification. A pre-welded in-line thermowell fits the constraint without compromising the measurement or the hygienic design.
What is an in-line thermowell?
An in-line thermowell is a thermowell already welded into a short section of pipe, delivered tested and polished, ready to be orbital-welded into the line. Because it is pre-welded in the workshop, no certified welds or radiographic testing are needed at the installation site.
Does it need certified welding or X-ray testing on site?
No. The thermowell is pre-welded and pressure tested to 40 bar in the workshop, so only a standard orbital weld of the pipe section is required at installation — no on-site certified welds or radiographic testing.
What sizes and materials are available?
Sizes from ¼" to DN50 in EN 1.4404 / AISI 316L stainless steel, pressure tested to 40 bar, with custom lengths and materials on request. Each unit carries an engraved HEAT number and is supplied with 3.1 certification.
Measuring temperature in a small or hygienic pipe?
Tell us the pipe size, process connection, temperature range and documentation you need, and we’ll put together the right in-line thermowell and sensor.
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