Direct OEM manufacturing solutions engineered for extreme thermal, mechanical, and corrosive process environments.
A bimetal strip thermometer is a self-contained, mechanical temperature indicator that translates thermal energy into mechanical movement without requiring external electrical power. This robust device relies on the differential thermal expansion properties of two dissimilar metals physically bonded together under extreme pressure.
The fundamental driving force is the difference in thermal expansion coefficients ($\alpha$). A high-expansion metal alloy (such as brass or nickel-iron alloy) is cold-welded to a low-expansion metal alloy (such as Invar, a 36% nickel-steel alloy). When exposed to thermal fluctuations, the unequal dimensional changes force the metallic strip to bend towards the side with the lower coefficient.
To maximize angular displacement within a compact stem, OEM manufacturers wind the bimetallic strip into a helical coil or flat spiral ribbon. Helical coils are positioned within slender stainless steel stems for immersion in fluid or gas pipes, while spiral coils are frequently used in surface mount applications and ambient HVAC dials.
One end of the helical bimetal coil is anchored permanently to the tip of the protective stem, while the opposite free end connects directly to a low-friction pointer shaft. As thermal changes deform the helix, the shaft rotates axially. This rotational movement directly drives the pointer across a calibrated dial face, providing accurate temperature readouts with linear repeatability.
The mathematical curvature ($\frac{1}{\rho}$) of a bimetallic strip subjected to a temperature differential ($\Delta T$) is governed by Timoshenko's classic beam theory:
$$\frac{1}{\rho} = \frac{6 (\alpha_2 - \alpha_1) (1 + m)^2 \Delta T}{t \cdot \left(3(1+m)^2 + (1+m \cdot n)(m^2 + \frac{1}{m \cdot n})\right)}$$
Where $\alpha_1, \alpha_2$ represent the expansion coefficients, $t$ is the total strip thickness, $m$ is the thickness ratio of the metals, and $n$ is the ratio of their elastic moduli. In OEM manufacturing, exact mechanical calibration ensures linearity across ranges from -70°C up to +600°C.
Tailored engineering specs designed to integrate seamlessly into complex process infrastructure, OEM machinery, and severe service conditions.
| Specification Category | Standard Factory Options | OEM Customization Capability | Target Application / Industrial Value |
|---|---|---|---|
| Dial Diameters | 2.5" (63mm), 3" (80mm), 4" (100mm), 6" (160mm) | Custom dial graphics, dual scales (°C/°F), logo branding | Optimal legibility from short or long distance inside industrial plants. |
| Mounting Configuration | Bottom Mount, Center Back Mount, Every-Angle Mount | Adjustable stem angle (360° swivel joints), flange mounts | Versatile installation in tight piping manifolds and vessel walls. |
| Stem Diameter & Length | Ø 6.0mm, 6.35mm (1/4"), 8.0mm; Length 50mm to 1000mm | Custom stepped stems, fast-response tapered tips, thermowell fits | Ensures deep thermal penetration without interrupting high fluid velocities. |
| Material Engineering | AISI 304 Stainless Steel, AISI 316 Stainless Steel | 316L SS, Hastelloy C276, Monel 400, PTFE Coatings | Prevents pitting corrosion in marine, chemical, and offshore environments. |
| Electrical Switch Contacts | N/A (Standard Gauge) | Single/Double Magnetic Contacts, Inductive Proximity Switches | Automated upper/lower thermal limit alarms and process relay tripping. |
| Environmental Sealing | IP65 Weatherproof Enclosure | Hermetically sealed IP67/IP68, Liquid-Filled (Glycerin/Silicone) | Eliminates pointer flutter caused by mechanical vibration; prevents lens fogging. |
OEM bimetal thermometers can be integrated with adjustable magnetic snap-action or inductive switches to automatically control valves, pumps, and emergency shutdown units based on real-time temperature thresholds.
Featuring internal silicone dampening fluid and heavy-duty helical spring anchors, our gauges withstand continuous mechanical vibration without losing alignment or incurring internal gear wear.
Designed specifically for pharmaceutical and food/beverage plants, featuring ultra-smooth electro-polished surfaces ($Ra \le 0.4 \mu m$) compliant with CIP/SIP sterilization standards.
Featuring a robust stainless steel universal joint stem, enabling field engineers to swivel the dial head 180° and rotate it 360° for optimal visibility at any pipe orientation.
Huzhou Accuracy Instrument Co., Ltd. is professionally engaged in the development, sales, and service of high-precision industrial mechanical pressure gauges, bi-metal thermometers, SF6 manometers, and advanced pressure sensors.
Established over two decades ago, our state-of-the-art manufacturing facility spans 3,000 square meters. Equipped with automated production lines, laser welding technology, and strict quality control systems, we deliver scalable measurement solutions to global OEM partners.
Our facility operates strictly under ISO 9001:2008 management standards. Every unit undergoes 100% thermal cycle testing and environmental simulation to ensure zero-leak performance and ±0.5% precision durability.
Leveraging complete vertical integration to supply global buyers with high-precision instruments at competitive price points.
Our strategic proximity to Yangtze River Delta metallurgical hubs allows direct sourcing of high-grade 304/316 stainless steel and precision bimetallic ribbons. Bulk purchasing cuts raw material overhead by 15-22% compared to Western manufacturers.
State-of-the-art robotic laser welding machines ensure airtight sealing between the stem sheath and process connection fittings. Automated winding machines establish precise pitch uniformity across every helical spring coil produced.
With an annual output exceeding 2,000,000 units, our agile manufacturing scheduling processes sample requests within 3 to 5 business days and complete full production orders in under 3 weeks.
Proven field reliability across extreme environmental conditions and critical process infrastructure worldwide.
Installed on hydrocarbon distillation towers, cracking units, and pipeline manifolds. Stainless steel 316 weather-proof housings resist ambient saltwater spray and aggressive chemical vapors.
Monitoring heavy water boilers, steam distribution mains, and chilled water loops. Every-angle adjustable heads allow easy readouts inside dense mechanical room piping matrices.
Configured with sanitary Tri-Clamp fittings and inert silicone dampening fluids. Built to withstand high-pressure steam Clean-in-Place (CIP) routines without zero-point drift.
Integrated into high-voltage electrical switchgear and transformer oil tanks. Electric contact bimetal thermometers trigger automated cooling fans or circuit isolation breakers.
In-depth technical answers curated by our R&D engineering department to assist procurement managers and plant operations personnel.
High-precision instrumentation designed to seamlessly integrate into your OEM equipment catalog.
Accuracy Instrument
