Druck PTX400 Subsea Wellhead Pressure and Temperature Transmitter

Pressure and temperature transmitters for subsea wellheads and manifolds

The Druck PTX400 series is designed for long-term use on subsea wellheads and production manifolds. The family covers pressure (PTX 400), temperature (TTX 400) and combined pressure and temperature (PTTX 400) transmitters, and the design is based on API performance requirement PR1 and product specification level PSL3.

The pressure element is the same micromachined piezo-resistive silicon technology used across Druck sensors, in an all-welded Inconel 625 assembly with high containment. Temperature measurement in the TTX and PTTX variants uses a fully integrated high-performance platinum resistance sensor over a range of -40 to 150 degrees C. Units are suitable for continuous use in excess of 25 years when immersed in salt water at depths of up to 3000 m.

Customised designs are available, including other process and electrical connections.

Technical specifications

How to specify a PTX400

The datasheet asks for four items: the type number (PTX 400, PTTX 400 or TTX 400), the operating pressure range and reference (sealed gauge or absolute, for PTX and PTTX only), and the process and electrical connections. Because the connections are application specific, the datasheet directs the buyer to Druck for the connector arrangement.

Typical drivers are the wellhead flange class, the subsea connector standard used by the control system, the pressure and temperature range at the tree and whether the combined PTTX version replaces two separate sensors. For smaller subsea control modules, see the compact Druck UNIK 5000 platform on this site, or the PTX300 on this catalogue.

What to confirm before ordering

Confirm flange type, pressure range, temperature requirement, connector type and the required documentation package. Because the unit weighs 13.5 kg and is customised, lead time and configuration are confirmed at quotation rather than assumed.

Role of the PTX400 in subsea production monitoring

On a subsea tree or production manifold, pressure and temperature readings are the basic data that operators use to understand how a well is behaving. They show whether a choke setting is giving the expected flow conditions, whether pressure is building or falling over time, and whether the fluid temperature indicates changes in the reservoir or in the flowline. Because these points cannot be reached easily once the equipment is installed on the seabed, the transmitter is expected to give stable readings for the life of the field with minimal attention.

This is why the PTX400 family is built around an all-welded Inconel 625 assembly with high containment and a secondary containment barrier. The welded construction avoids the leak paths that a bolted or threaded assembly would introduce, and the containment design is intended to keep well fluids inside the instrument even under abnormal conditions. The design basis on API PR1 and PSL3 places the transmitter within the qualification framework that wellhead equipment specifiers already use.

Choosing between PTX, TTX and PTTX

The choice between the three versions follows the measurement plan for the tree or manifold. Where only pressure is required at a given point, the PTX 400 is the direct choice. Where temperature alone is needed, the TTX 400 uses the integrated platinum resistance sensor. Where both are required at the same location, the combined PTTX 400 can reduce the number of penetrations in the flange arrangement and the number of connections back to the control system, which simplifies the subsea layout.

Range selection should reflect the shut-in and flowing pressures expected at the tree, with sensible margin, together with the choice between sealed gauge and absolute reference. Since the process and electrical connections are application specific, they are best agreed early in the design so that the transmitter fits the flange class and the subsea connector standard of the project.

Integration with subsea control systems

The standard output is a two-wire current loop, which is widely understood by subsea control module electronics and topside systems. The supply voltage relationship given in the specification table helps the engineer check that the loop resistance in the umbilical and control electronics leaves enough voltage at the transmitter. Compatibility with the major proprietary subsea connector types means the unit can be matched to the connector system already chosen for the field, rather than forcing a change of interface.

When combined pressure and temperature data are brought topside, they can be trended alongside other well data to support production optimisation, flow assurance studies and integrity monitoring.

Practical points for projects in Oman and the GCC

Offshore developments in the Gulf region typically involve warm seawater, saline conditions and long design lives, all of which favour the corrosion-resistant welded construction described above. Handling should reflect the weight and value of the unit: lift with suitable equipment, protect the flange faces and connector during storage and transport, and keep the unit in its packaging until installation. Surface testing before deployment should follow the project procedures and the manufacturer documentation.

Because each unit is configured for its application, collecting the type number, range, reference, flange and connector information in one technical query helps the quotation stage move without repeated clarification.

Documents and quotation

The attached file is the four-page Druck PTX 400 series datasheet dated April 2026. Send the type, range and connection details to Seven Star LLC for a quotation. Related products are in Pressure Instrumentation.