Gauges - Thermometers

Gauges - Thermometers

In industrial process control, mechanical thermometer gauges – including bi-metal and expansion types – provide reliable local temperature readings without external power. These instruments offer high reliability and durability, making them suitable for use across a wide range of industries and even in harsh environments.

Bi-metal thermometers use a coil of two bonded metal strips with different thermal expansion rates. As temperature changes, the coil twists and moves a pointer on the dial. This simple design is cost-effective and provides accurate readings over moderate temperature ranges.

Expansion thermometers rely on a fluid (gas or liquid) sealed in a bulb and tube. Heat causes the fluid to expand and increase pressure, flexing an element (like a Bourdon tube) that moves the pointer. With a capillary, the dial can be mounted remotely, allowing monitoring of hard-to-access points. They provide a clear analog dial readable from a distance, keeping operators away from hazardous equipment. Because they need no external energy, these thermometers are safe to use in flammable areas and require minimal maintenance.

Typical applications include boilers, reactors, pipelines, and HVAC systems — any setting requiring on-site temperature monitoring.