PMP51B Metal Diaphragm Pressure Transmitter

Where ceramic measuring cells reach their limits, the PMP51B keeps working. Rather than a fragile ceramic diaphragm, it senses pressure through a weldable metal membrane – and that one design decision unlocks the two conditions ceramic transmitters handle worst: very high line pressure, and very hot or very cold process media. Because the wetted face is metal, it also shrugs off aggressive chemistry that would degrade polymer-lined ceramic cells.

Two accuracy classes are offered. The standard build holds a reference accuracy down to 0.075%, while the platinum-trimmed variant tightens this to 0.055% for custody-transfer metering and precision batching. A 100:1 turndown ratio combined with a 20 mbar minimum calibrated span lets field staff re-range the unit on site – no spare sensors and no hardware change.

Operating envelopes are deliberately wide. The sensing element spans 400 mbar up to 400 bar and survives a 600 bar overpressure event, so pipeline water-hammer and sudden spikes no longer destroy the cell. Standard electronics cover process media from -40°C to +125°C; once a remote diaphragm seal and a matched fill fluid are fitted, the measurable window widens to -70°C ~ +400°C, reaching cryogenic refrigerants, live steam and heat-transfer oil.

Long-term cost control comes from drift. First-year stability is 0.1% URL, 0.2% URL at five years and 0.25% URL after a decade, so scattered measurement points no longer need an aggressive recalibration schedule.

On the wetted side, process diaphragms are selectable in 316L, Alloy C, Tantalum, Monel or PTFE-lined steel, backed by PTFE gaskets and four fill-fluid families (silicone, inert, vegetable, and dedicated high/low-temperature oils). For signals, the unit offers 4-20mA, 4-20mA HART and PROFINET Ethernet-APL, plus an optional Bluetooth link to the SmartBlue app, an embedded RFID tag and a guided commissioning wizard.

Compliance is global: ATEX, IECEx, CSA C/US and NEPSI for explosion protection, SIL for functional safety, EN10204-3.1 with NACE MR0175 / MR0103, NSF drinking-water and hygienic qualifications, and marine classification – all delivered in graded wide-voltage form to match every protection type.

The matrix below lists every factory specification for the PMP51B metal-diaphragm transmitter – dual accuracy grades, the full temperature and pressure envelope with optional remote seal, the corrosion-resistant wetted metallurgy, the fill-fluid options, the multi-protocol digital outputs and the complete certification set. Please quote against the finished order code and full supporting documents.

Metal sensing core, seal-ready

Weldable corrosion-resistant diaphragms in 316L, Alloy C, Tantalum and Monel, or a PTFE-lined face, outlast ceramic cells in harsh fluids. A bolt-on remote diaphragm seal lifts the measurable medium window to -70°C ~ +400°C, so molten-hot media, cryogenic liquids and viscous, crystallising products can be metered without ever touching the transmitter body.

Two accuracy tiers and a ten-year stability story

Reference accuracy of 0.075% (standard) or 0.055% (platinum) satisfies tight trade-metering and batching rules. Year-on drift as low as 0.1% URL keeps readings repeatable for up to a decade, slashing the calibration labour and downtime at large measurement estates.

Headroom for pressure and vacuum alike

A 400 mbar-to-400 bar span with a 600 bar overpressure ceiling suits heavy-duty lines, while separately specified vacuum resistance – 10 mbar abs for the bare unit, 50 mbar abs for the seal version – holds steady in vacuum distillation and low-pressure gas service. The 100:1 turndown lets you narrow or widen the range in the field without a new sensor.

An unusually wide thermal window

The standard model tolerates -40°C ~ +125°C process media; pairing a matched seal and fill fluid pushes this to a cryogenic -70°C at one end and +400°C at the other. Ambient resilience of -40°C ~ +85°C covers frozen outdoor racks, hot plant rooms and open-deck marine piping.

Configurable wetted parts and fill fluids

Pick the alloy and PTFE lining that fit acidic, alkaline, sulphur-bearing or potable media. Four fill-fluid families are matched to the seal to stop the medium freezing or flashing at temperature extremes, and PTFE gaskets hold a dependable seal through long continuous campaigns.

Multi-protocol comms with Bluetooth O&M

Plain 4-20mA, HART and PROFINET Ethernet-APL tie into legacy indicators and modern DCS alike. Optional Bluetooth to the SmartBlue app enables cable-free setup, fault diagnosis and data logging, while a built-in RFID tag, a guided commissioning wizard and plug-and-play design shorten start-up. Graded DC supply – 10.5-35V for Ex d / Ex e / non-Ex and 10.5-30V for Ex i – rides out loop voltage swings without signal error.

Hygienic fittings and a global approval set

Beyond standard threads and DN/NPS flanges, dedicated hygienic process connections serve European, American and Asian pipework for food, beverage and pharma duty. Shipped approvals span international explosion protection, SIL, NACE, NSF drinking water, hygienic and marine classification, with EN10204-3.1 inspection reports for acceptance and audits.

Petrochemical, refining & oil-and-gas

NACE anti-sulphur approval, several corrosion-resistant diaphragm alloys and 600 bar overpressure protection make the PMP51B fit for crude lines, gas delivery loops, high-pressure reactors and sour service. A remote seal reaches hot thermal oil and cryogenic liquefied gas, while HART and PROFINET feed centralised DCS control across refineries and chemical complexes.

High-temperature and cryogenic plant

Spanning -40°C ~ +125°C as standard and -70°C ~ +400°C with a matched seal, the unit is deployed on steam lines, heat-transfer-oil loops, low-temperature refrigeration and cryogenic tank monitoring. Purpose-built high/low-temperature fill fluids prevent the medium from solidifying or vaporising at the extremes.

Corrosive chemical production

316L, Alloy C, Tantalum, Monel and PTFE-lined diaphragms absorb acid, alkali and chloride attack. PTFE gaskets sustain sealing across continuous batch runs, and the split vacuum ratings support pressure control on vacuum columns and low-pressure synthesis reactors.

Food, beverage & pharmaceutical hygiene

Dedicated hygienic connections, NSF drinking-water and hygienic qualifications suit sterile batch tanks, filling lines and pure-water circuits. The cleanable metal-diaphragm wetted path resists residue and cross-contamination, and Bluetooth SmartBlue tuning limits dismantling inside clean rooms.

Offshore & marine

Backed by full marine classification and rated -40°C ~ +85°C ambient, it holds pressure watch over ship fuel lines, ballast systems and deck heat exchangers, with overpressure margin for the surges of unstable marine fluid loops.

Precision metering & automation

Two accuracy tiers and a 100:1 turndown cover custody transfer and low-level detection, and the 20 mbar minimum span captures the subtle changes seen on new-energy assets, environmental stations and laboratory-grade instrumentation.

Verified accuracy and stability

Every unit is full-span factory-calibrated to its marked 0.075% or 0.055% grade. The metal sensing core holds drift to 0.1% URL/year, 0.2% URL over 5 years and 0.25% URL over 10 years, and each transmitter clears overpressure and vacuum tests before shipping.

Complete certification on request

Full document sets are supplied as needed: ATEX, IECEx, CSA C/US and NEPSI, SIL functional safety, NACE MR0175/MR0103, NSF drinking water, hygienic qualification and marine classification, with EN10204-3.1 inspection reports for acceptance and third-party audits.

Tailored wetted parts and seal matching

Diaphragm alloys, PTFE lining, gaskets and the four seal fill-fluid families are configured to your medium's corrosivity and process temperature. The remote diaphragm seal isolates ultra-hot or ultra-cold media that must not touch the sensor body.

Comms and power supply tested before dispatch

All outputs (4-20mA, HART, PROFINET Ethernet-APL, optional Bluetooth) and the graded wide-voltage supply are pre-checked, so the RFID tag, commissioning wizard and plug-and-play design install cleanly without extra tooling.

Standardised, model-based supply

Quotes are issued strictly against the customer's finished order code; we do not provide independent model-selection advice. Our engineers verify parameter matching for the ordered code and deliver the full certification package for smooth commissioning.

How is the PMP51B different from a ceramic-cell transmitter such as the PMC51B?

The PMP51B senses through a corrosion-resistant metal diaphragm and supports a remote diaphragm seal, so it spans pressures up to 400 bar and media from -70°C to +400°C, with several anti-corrosion alloy choices. It is built for the high-pressure, strongly corrosive, cryogenic and ultra-hot duties where a ceramic cell is out of its depth.

Does it measure gauge and absolute pressure?

Yes. One device carries both gauge and absolute modes, covering open-line pressure, sealed-vessel pressure and vacuum-reactor monitoring.

How hot or cold can the sealed version get?

The bare unit handles -40°C ~ +125°C process media. With a matched diaphragm seal and dedicated fill fluid, the measurable window widens to -70°C ~ +400°C for cryogenic gas, live steam and heat-transfer oil.

Which wetted materials suit corrosive media?

Diaphragms come in 316L, Alloy C, Tantalum, Monel and PTFE lining; all gaskets are PTFE. A choice of fill fluids is matched to the seal for each temperature and corrosion profile.

What signals are available?

Standard 4-20mA, intelligent 4-20mA HART and PROFINET Ethernet-APL digital bus. Optional Bluetooth links to the SmartBlue app for cable-free setup and diagnosis, and an RFID tag is built in for quick asset ID.

Which compliance documents ship with it?

Global explosion-proof certificates, SIL functional safety, NACE anti-sulphur, NSF drinking water, hygienic and marine classification approvals, with EN10204-3.1 factory reports available on request.

What overpressure and vacuum can it take?

Up to 600 bar overpressure. Vacuum resistance is 10 mbar abs for the standard type and 50 mbar abs for the diaphragm-seal type, stable under long-term low-pressure and vacuum duty.

Does it need frequent recalibration?

No. Annual drift of just 0.1% URL keeps readings consistent and repeatable for up to ten years, sharply cutting routine calibration labour.

Need PMP51B metal-diaphragm pressure transmitters, a customised remote-seal configuration, specialist anti-corrosion wetted materials? Send us your exact finished order code for an accurate quotation, or contact our team to plan your industrial measurement procurement.

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