Strain gauge pressure transmitter HWJ

digitalHART1/2" UNF

Product overview
The HWJ Melt pressure transmitter is a HART‑enabled pressure transmitter engineered for high‑temperature process applications and use in potentially explosive atmospheres. It measures media pressure at temperatures up to 315°C using hydraulic pressure transmission to a strain‑gauge sensing cell, providing a robust electrical output compatible with HART communication.

Main features

• Digital output: HART protocol
• Flameproof housing: Ex d (isolation for hazardous areas)
• Certified: IECEx, ATEX, NEPSIEx (FM approval where specified)
• Designed for melt/high‑temperature media (media temperature up to 315°C)
• Pressure ranges from 0–17 bar up to 0–1000 bar
• Accuracy options: < ±0.25% FS (H); < ±0.5% FS (M)

Protection, certification and operating conditions

• Designed and manufactured in accordance with ATEX Directive 2014/34/EU and IECEx Scheme
• Group II, category 2G and 2D (EPL Gb/Db)
• Gas protection: Ex db IIC T6 / T5 Gb
• Dust protection: Ex tb IIIC T85°C / T100°C Db
• Ambient temperature ranges: -20°C to +60°C (T6); -20°C to +85°C (T5)

Construction and measuring principle
Hydraulic transmission of pressure uses an incompressible fill fluid to transfer mechanical stress from the process to the sensing diaphragm. A strain‑gauge measuring cell converts mechanical strain into an electrical signal. Diaphragm materials and protective coatings are selected for compatibility with aggressive and high‑temperature melt media.

Mechanical and mounting

• Standard process connections: 1/2-20 UNF, M18x1.5
• Optional mounting flange: Ø66.3 mm (2.61 in)
• Diaphragm materials: 15‑5 PH stainless steel with GTP+ coating; for ranges below 100 bar a 17‑7 PH corrugated diaphragm with GTP+ coating is used
• Other diaphragm types and customized process connections available on request

Typical applications

• Melt pressure measurement in polymer processing, extrusion and compounding
• High‑temperature industrial processes requiring HART integration
• Zones with explosive atmosphere risks (gas and dust) where Ex certified instrumentation is required

Technical specifications

• Model: HWJ
• Pressure ranges: 0–17 bar up to 0–1000 bar (0–250 psi up to 0–15000 psi)
• Measuring principle: strain gauge with hydraulic transmission
• Media temperature capability: up to 315°C
• Accuracy: < ±0.25% FS (H); < ±0.5% FS (M)
• Output: HART digital protocol
• Explosion protection: Ex db (gas), Ex tb (dust); IECEx, ATEX, NEPSIEx certified
• Ambient temperature: -20°C / +60°C (T6); -20°C / +85°C (T5)
• Process connections: 1/2-20 UNF, M18x1.5; optional flange Ø66.3 mm
• Diaphragm: 15‑5 PH SS (GTP+); 17‑7 PH corrugated for low ranges