Strain gauge pressure transmitter W7 SIL2

voltage output4-20 mA1/2" UNF

Overview
The W7 SIL2 pressure transmitter by Gefran is designed for high-temperature melt applications. It uses a diathermic oil-filled hydraulic transmission to transfer pressure to a thick-film strain-gauge sensor, enabling stable measurements for media temperatures up to 315°C. The SIL2-certified variant is intended for safety-related process installations.

Main features

• Pressure ranges: 0-35 to 0-1000 bar (0-500 to 0-15000 psi)
• Accuracy: < ±0.25% FS (H); < ±0.5% FS (M)
• Diathermic oil filling for thermal stability (FDA CFR 178.3620 and CFR 172.878 compliant)
• SIL2 certification for Functional Safety
• Standard threads: 1/2-20 UNF, M18x1.5; other threads on request
• Diaphragm: 17-7 PH corrugated with GTP+ coating; alternatives available
• Output: voltage options (examples: 0.5–10.5 Vdc) and current options (4–20 mA) depending on configuration
• Configurable stems: rigid, rigid+flexible, thermocouple, exposed capillary
• Autozero on-board or external; drift autocompensation option (SP)

Detailed description
The W7 principle is hydraulic transmission: pressure from the measured medium is conveyed through an incompressible fluid to the sensing element, isolating the sensor from high temperatures and ensuring stable response. Thick-film strain-gauge transduction provides a stable electrical output. SIL2 versions include design and verification provisions to meet functional safety requirements in process plants such as polymer production.

Configuration snapshot (example)
Order code example: W--7-0-6-H-B17U-1-4-0-S-E-000. Example options: output 0.5..10.5 Vdc; configuration: rigid rod; connector: 6-pin; accuracy H (< ±0.25% FS); range B17U (17 bar); thread 1/2-20 UNF; rigid stem 153 mm; SIL2 designation S; autozero external (E).

Technical specifications

• Series: W7 (SIL2 variants available)
• Measuring principle: hydraulic transmission to thick-film strain-gauge sensor
• Media temperature capability: up to 315°C
• Filling: diathermic oil (FDA compliant)
• Pressure ranges and accuracy as listed above
• Connector and output options configurable (6-pin, 8-pin; voltage/current outputs)
• Mechanical options: thread types, stem lengths and special diaphragms on request

Applications

• High-temperature melt pressure measurement (polymer extrusion, compounding)
• Process plants requiring temperature-stable pressure measurement up to 315°C
• Safety-critical installations with SIL2 functional safety requirements