Explore our core engineering lineup of diaphragm seal pressure gauges, sensors, and bimetallic temperature controls.
Two Decades of Excellence in Industrial Mechanical Pressure Gauges & Sensing Solutions
Established over two decades ago, Huzhou Accuracy Instrument Co., Ltd. has grown into an international leader in pressure and temperature measurement engineering. Operating out of a state-of-the-art 3,000 square meter manufacturing facility, our factory integrates computerized laser welding, helium leak mass spectrometry, and automated micro-calibration rigs to produce over 2 million precision units annually.
We cater directly to global procurement directors, OEM engineering teams, and system integrators who require absolute zero-defect execution. Our custom diaphragm seal pressure gauges are purpose-built to isolate delicate elastic elements from aggressive media—including highly corrosive acids, viscous sludges, crystallizing liquids, and extreme thermal fluid loops.
Staffed by 20 specialized senior engineers focusing on diaphragm foil metallurgy, thermal expansion fluid dynamics, and smart sensor integration. Our R&D team ensures compliance with API 610, ASME B40.100, and ISO standards, securing breakthroughs in low-pressure diaphragm deflection accuracy.
Driven by 120 certified technical specialists utilizing automated micro-TIG and laser seal welding systems. High-vacuum evacuation and automated fluid fill equipment guarantee 100% bubble-free hydraulic transmission across wide operating temperature bands.
Our 15 global technical representatives provide 24/7 engineering consultation, customized CAD model generation, material compatibility assessments, and application-specific calibration certificates (ISO 17025 / NIST traceable) for international procurement partners.
A comprehensive technical analysis on material compatibility, volumetric expansion displacement, and seal architecture for heavy-duty process isolation.
A diaphragm seal pressure gauge (also known as a chemical seal gauge) is an essential safety and measurement instrument designed to isolate the primary sensing element (Bourdon tube or piezoresistive chip) from harsh medium conditions. When process media are aggressive, toxic, highly viscous, prone to crystallization, or operating at elevated temperatures, direct gauge contact leads to rapid corrosion, clogging, thermal drift, or catastrophic rupture.
The process pressure exerts force upon an elastic, flexible metallic or synthetic diaphragm seal. The deflection of the diaphragm compresses an incompressible system fill fluid (e.g., silicone oil, fluorolube, or high-temperature synthetic oil) contained within a hermetically sealed cavity. This fluid hydraulically transmits the exact pressure to the Bourdon tube or sensor element, yielding precise static and dynamic pressure readings without allowing process media to contaminate internal working components.
Choosing the correct diaphragm material is pivotal to preventing chemical erosion, pitting, and embrittlement. Huzhou Accuracy Instrument Co., Ltd. manufactures diaphragms using ultra-thin, high-grade metallic foils ranging from 0.05 mm to 0.15 mm in thickness, engineered for maximum elastic flexibility and corrosion resistance:
| Wetted Diaphragm Alloy | Chemical Resistance Profile | Ideal Application Environments | Temperature Limit |
|---|---|---|---|
| Stainless Steel 316L (1.4404) | General industrial chemical resistance, low organic acid vulnerability, robust mechanical toughness. | Water treatment, standard HVAC, light chemical processing, hydraulic lines. | -40°C to +200°C |
| Hastelloy C-276 (2.4819) | Exceptional resistance to wet chlorine gas, hypochlorites, chlorine dioxide, and strong oxidizing salts. | Petrochemical refining, paper pulp processing, marine flue gas scrubbers. | -40°C to +400°C |
| Tantalum (UNS R05200) | Corrosion resistance chemical reactivity equivalent to glass; immune to concentration sulfuric/hydrochloric acids. | Severe chemical synthesis, aggressive acid dosing, pharmaceutical acid processing. | -40°C to +300°C |
| Monel 400 (UNS N04400) | Superior resistance to hydrofluoric acid, saline environments, sea water, and alkalis. | Offshore platforms, marine desalination, hydrofluoric acid alkylation units. | -40°C to +350°C |
| PTFE Coating / Lining | Anti-stick surface preventing polymer adhesion, immune to organic solvents and concentrated alkalis. | Electroplating, wastewater slurry, sticky latex and resin production. | -20°C to +150°C |
The system fill fluid acts as the mechanical transmitter. The selection of fill fluid must consider process operating temperatures, ambient swing range, system response time, and toxicity guidelines (especially for sanitary applications):
Offers excellent viscosity-temperature stability. Suitable for general industrial use from -40°C to +200°C. Provides linear thermal expansion characteristics and low compressibility.
Engineered for high-temperature chemical reactions up to +400°C, or oxygen/chlorine service where synthetic oils must remain non-reactive and non-flammable.
Non-toxic vegetable glycerine or specialized white mineral oil compliant with FDA 21 CFR 178.3570, ensuring absolute process safety in pharmaceutical and food manufacturing.
How Huzhou Accuracy Instrument combines advanced automated manufacturing with optimized localized supply chains to deliver global value.
Situated in the heart of Yangtze River Delta industrial hub (Huzhou, Zhejiang), our plant leverages seamless regional access to premium raw stainless steel stock, high-precision machining centers, specialized laser welding sub-contractors, and direct maritime logistics via Ningbo and Shanghai ports. This cluster reduces lead times for raw materials by 40% compared to Western counterparts.
Every customized diaphragm seal system undergoes rigorous testing in our vacuum chambers using helium leak mass spectrometers capable of detecting micro-fissures down to < 1×10⁻⁹ mbar·l/s. This guarantees a "zero-leak" envelope, extending calibration life and preserving oil purity under violent process pressure fluctuations.
Custom-engineered diaphragm seal configurations addressing application challenges across global process sectors.
Designed for severe sour gas (H2S), hydrocarbon cracking, and offshore platforms. Our NACE MR0175/MR0103 compliant Hastelloy C-276 and Inconel 600 flanged diaphragm gauges provide explosion-proof (ATEX/IECEx) electrical contacts to trigger emergency shutoff alarms safely.
Featuring quick-release Tri-Clamp and SMS sanitary connections with surface roughness Ra ≤ 0.38 µm. Electropolished wetted parts eliminate bacteria traps, accommodating CIP (Clean-in-Place) and SIP (Steam-in-Place) sterilization cycles up to +150°C.
Specialized SF6 gas density monitors with integrated temperature compensation mechanisms. Prevent dangerous arc discharges in high-voltage switchgear substations by providing ultra-reliable pressure trend signals and alarm contacts.
Ensuring smooth international integration through strict adherence to worldwide quality standards and regulatory frameworks.
Huzhou Accuracy Instrument Co., Ltd. operates under a certified ISO 9001:2008 / ISO 9001:2015 Quality Management System. Our industrial diaphragm gauges and switch contacts carry full CE Mark Certification, adhering to Pressure Equipment Directive (PED 2014/68/EU) standards.
We work directly with OEM instrument distributors and EPC project contractors across Europe, North America, Southeast Asia, and the Middle East, offering:
Pioneering smart sensing, digital twins, and next-generation diaphragm materials to power the future of smart factories.
Integrating ultra-low power LoRaWAN, NB-IoT, and Bluetooth Low Energy (BLE) modules into traditional mechanical diaphragm seal bodies. Allows plant managers to remotely monitor process pressure trends and receiving predictive vibration alerts without installing expensive signal cabling.
Developing embedded micro-strain sensor arrays within the diaphragm cavity. Real-time stress dynamic modeling calculates structural deflection wear, predicting diaphragm metal fatigue or fill oil degradation before operational leakage occurs.
Pioneering nanostructured CVD diamond-like coatings (DLC) and gold/tantalum multilayer sputtering. These next-gen surface treatments offer 500% greater abrasion resistance against abrasive slurries and sand-laden crude oils.
Discover our extended catalog of shock-resistant, electric contact, and bimetallic instruments.
Adhering to strict business management models and quality benchmarks certified under ISO9001:2008 and international directives.
Detailed engineering answers regarding selection, customization, logistics, and maintenance of diaphragm gauges.
Standard Bourdon tube gauges allow the process medium to enter directly into the narrow coiled sensing tube. If the process fluid is corrosive, slurry-laden, highly viscous, or prone to freezing/solidification, it will rapidly clog or rupture the internal tube. A diaphragm seal provides a physical barrier (using Hastelloy, Tantalum, or Stainless Steel foils), transferring pressure via fill oil while keeping harsh media completely separated from internal gauge mechanics.
System fill fluids expand or contract under temperature variations, creating internal thermal expansion pressure against the flexible diaphragm (known as temperature effect error). Huzhou Accuracy Instrument minimizes temperature drift by optimizing fill fluid volumes, employing micro-bore capillaries, and utilizing computerized calibration algorithms to ensure precise accuracy across thermal operating spans from -40°C to +400°C.
For severe acids such as concentrated Hydrochloric (HCl), Hydrofluoric (HF), or Sulfuric Acid (H2SO4), we strongly recommend Tantalum wetted diaphragms or pure PTFE sheet linings. Tantalum possesses corrosion resistance characteristics comparable to platinum and glass, offering long-term reliability under severe chemical exposure.
Yes. We specialize in OEM/ODM customization. We produce wetted parts matching ANSI/ASME B16.5 (1/2" to 3" flanges), DIN EN 1092-1, JIS standards, as well as customized Threaded (NPT, BSP, G, metric) and Sanitary Tri-Clamp connections according to your engineering drawings.
Our 3,000 square meter factory maintains an annual output exceed 2,000,000 units. Standard production lead time for customized diaphragm seal pressure gauges ranges from 2 to 3 weeks depending on material sourcing (e.g., Hastelloy/Tantalum). Flexible MOQ options are available to support initial engineering evaluations and prototype testing.
Accuracy Instrument