Instrument Enclosure Temperature Control

Instruments exposed to adverse conditions should be protected in fully enclosed and insulated boxes to avoid physical or weather damage. Even in enclosures, instrumentation can be exposed to freeze damage or overheating. When the enclosure temperature is too high, fluids can vaporize or change viscosity or color. When temperatures are too low, fluids in the lines can freeze or thicken – resulting in physical damage and operation malfunction to sensitive equipment.

For many samples and instrumentation, the temperature will affect measurement accuracy. The best way to solve this problem is to equip enclosures with systems designed to maintain the interior temperature within a specified range for optimal performance.

The most common methods for enclosure temperature control are electric or steam tracing. Electrical heating tracing is an effective method to prevent freezing; however, it can be very costly and poses risks of combustion from electrical sparks or freeze damage if the cable breaks or frays.

A more efficient method is steam tracing. In these systems, a small diameter copper or stainless-steel tube is dressed around the inside of an enclosure, or a coiled or finned tube heating element is installed within the enclosure. The elements from the steam main begin to circulate through the loop or heater, warming the inside of the box. Steam is an effective heating medium and does not create electrical sparks, making it the ideal solution for explosion-proof environments. However, it can still cause overheating if not adequately controlled.

ThermOmegaTech’s self-actuating steam temperature control valves are designed to provide safe and economic control of the heating medium to automatically regulate an enclosure’s internal temperature. These self-contained, temperature-activated valves simplify the control of steam flow and eliminate instrumentation overheating.

The TV/SC-I valve is installed into the enclosure wall so that the thermal actuator senses the ambient temperature inside it. Often used for freeze protection with steam as the media, the valve monitors the enclosure’s internal temperature and automatically regulates the flow of steam to maintain a set temperature.

If a design requires all connections to be within the enclosure using a steam coil to transfer heat, the TV/SC-A valve should be used. The self-actuating TV/SC-A thermostatic control valve senses enclosure temperature and allows the steam to flow to the coil to maintain the desired temperature inside. The ITCH assembly is a complete kit with a steam coil, mounting brackets, TV/SC/A, two TV/HAT valves, and tubing bulk-head fittings.

In reverse-acting operation, the TV/SC-IR valve regulates the flow of glycol, water, and other cooling media to keep the instrument enclosure cool.

The TV/SC-A, TV/HAT, TV/SC-I, TV/SC-IR, and ITCH kit work as temperature control analyzers to provide and maintain the optimal temperature in an enclosure.