Strain gauge pressure transmitter HMF

4-20 mAHARTflange-mount

Product overview
The HMF series are mercury-filled pressure transmitters with HART communication, designed for melt/high-temperature applications and use in hazardous (explosive) atmospheres. A fluid-filled hydraulic transmission ensures temperature stability and a strain-gauge sensor converts pressure into a 4–20 mA output with HART diagnostics. FM-approved variants are available.

Main features

• Pressure ranges: 0–17 to 0–1000 bar (0–250 to 15000 psi)
• Measurement principle: extensimetric (strain gauge)
• Output & communication: 4–20 mA with HART protocol
• Accuracy classes: < ±0.25% FS (H); < ±0.5% FS (M)
• Media temperature capability up to 400 °C (fluid-filled system)

Protection, approvals and environmental

• FM explosion-proof (XP) suitable for Class I, Division 1, Groups A–D
• Dust-ignition proof (DIP) for Classes II, III, Division 1, Groups E–G
• Indoor/outdoor protection: Type 4X, IP67
• Rated ambient temperatures examples: T5 Ta = -20 °C to +85 °C; T6 Ta = -20 °C to +60 °C

Mechanical and wetted parts

• Standard threads: 1/2-20 UNF and M18x1.5; mounting flange Ø 66.3 mm (2.61”)
• Standard diaphragm: 15-5 PH stainless steel with GTP+ coating
• For ranges <100 bar: 17-7 PH corrugated stainless steel diaphragm with GTP+ coating
• Other diaphragm materials and wetted parts available on request

Selectable versions and options

• Mechanical versions: rigid rod, rigid + flexible rod, versions with thermocouple, exposed capillary, flange mounting
• Connector / cable options and terminations (e.g. NPT cable variants)
• Performance/safety options: standard, SIL2, Performance Level (P = PL d) where applicable
• Autozero options: external (E) or magnetic (0); temperature class selection T5 or T6

Use case & function summary
The HMF transmitters are intended for measuring pressure in melts and other high-temperature media where stable measurement at elevated media temperatures and hazardous-area certification are required. HART provides remote diagnostics and configuration.

Technical specifications

• Product family: HMF (mercury-filled, HART, FM)
• Pressure ranges: 0–17 to 0–1000 bar (0–250 to 15000 psi)
• Measurement principle: extensimetric (strain gauge)
• Accuracy: < ±0.25% FS (H); < ±0.5% FS (M)
• Output: 4…20 mA with HART
• Media temperature capability: up to 400 °C
• Construction: fluid-filled hydraulic transmission
• Typical connections: 1/2-20 UNF, M18x1.5; mounting flange Ø 66.3 mm
• Approvals: FM Explosion-proof / DIP; Type 4X, IP67
• Rated ambient: T5 Ta = -20 °C to +85 °C; T6 Ta = -20 °C to +60 °C