High Pressure Transducers

Home › Products › Pressure Instruments › High Pressure Transducers

High pressure work splits into two bands. Up to about 100 MPa, a general-purpose unit like our SI-300 pressure transmitter does the job with a standard thread and a soft seal. Above that, in water jet cutting, high-pressure cleaning, pasteurization vessels, hydraulic test platforms and oilfield equipment, both the sensing element and the process connection have to change. The SI-702 series covers that second band.

Seal options

At a few hundred bar, any thread with a bonded washer seals fine. At a few thousand bar, soft seals extrude through the clearance gap, so ultra-high pressure fittings seat metal on metal: a polished sphere or cone pressed into a matching seat makes a narrow line of contact at enormous local stress, and that line is the seal. Which geometry you need is set by the port you already have.

Model	Type	Range	Connection	Notes
SI-702	Standard high pressure	0–40 to 0–600 MPa	Thread per order	The base model for hydraulic and test-bench work
SI-702S	Ultra-high pressure	0–1500 MPa standard	Per order	Higher custom ranges quoted case by case
SI-702Q	Spherical seal	Per order within series	Ball head	Adds 0–20 mV output option
SI-702Z	58° outer cone seal	Per order within series	Cone head	Extended version of the 702S
SI-702W	60° inner cone seal	Per order within series	M20 × 1.5 external thread	Multiple electrical interfaces
SI-702N	60° inner cone seal	Per order within series	M20 × 1.5 internal thread	Multiple body shapes available

Technical specifications

Parameter	Specification
Pressure ranges	0–40 MPa to 0–600 MPa; SI-702S 0–1500 MPa standard, higher ranges on request
Accuracy	0.1% FS, 0.2% FS or 0.5% FS
Output signal	4–20 mA (two-wire); 0–5 / 1–5 / 0–10 VDC (three-wire); 0–20 mV on SI-702Q
Power supply	24 VDC (10–30 VDC)
Medium temperature	−20 to 75 °C
Ambient temperature	−20 to 75 °C
Long-term stability	0.1% FS per year
Vibration effect	Less than 0.1% FS over 20–1000 Hz
Load resistance	Current output: 800 Ω max; voltage output: greater than 50 kΩ
Insulation resistance	Greater than 2000 MΩ at 100 VDC
Sensing body	Rare-metal alloy, one-piece integrated design, all stainless steel welded package, laser-trimmed temperature compensation
Factory screening	High and low temperature aging, long-term fatigue testing
Process connection	Ball head M20 × 1.5, cone head M20 × 1.5, M22 × 1.5; other threads to order
Electrical connection	Four-core aviation connector; Hirschmann connector optional
Protection	IP65

Specifications apply at room temperature and rated supply unless stated. Confirm the exact figure for your model and range on the order sheet.

Working principle

The principle is the same strain gage bridge used across our pressure line: process pressure deflects the sensing element, the bridge resistance shifts in proportion, and the electronics convert that shift to a 4–20 mA or voltage signal. What changes at ultra-high pressure is everything around the bridge. The one-piece alloy body removes welds and joints from the loaded path, and the heavy wall sets the burst margin.

Size the range so working pressure sits at 60 to 80% of full scale. From the case file: a calibration house in the Middle East needed a sensor for a 700 bar hydraulic pressure comparison pump, replacing a discontinued imported model. 700 bar is 70 MPa, so a 0–100 MPa unit carries the working point at 70% of span: headroom for pump overshoot, resolution where the measurement lives.

Quick connectors

We also supply matching high pressure quick connectors in 1/4 NPT and 3/8 NPT: high-strength carbon steel with galvanized finish, check valves at both ends and a steel ball lock, rated 10,000 psi (700 bar) working pressure with a 2× safety factor, −30 to 100 °C. They interchange with ENERPAC and Parker 3000 series fittings, which keeps an existing test bench plumbed without adapter stacks.

Ordering information

An SI-702 unit is built per application, not pulled off a shelf. The range and the seal geometry drive everything else, so settle those two first and the rest of the order is connector codes.

Ordering example: SI-702W, range 0–100 MPa, M20 × 1.5 external thread with 60° inner cone seal, 4–20 mA output, 24 VDC supply, four-core aviation connector, for a 700 bar hydraulic comparison pump. The working point sits at 70% of full scale.

Applications

Related products

FAQ

What does a high pressure transducer do?

It measures very high pressures and converts them to an electrical signal. The SI-702 handles ranges into the high-megapascal region (standard to 1500 MPa) with a rugged sealed sensing element, outputting 4–20 mA proportional to pressure.

What are the three types of pressure transducers?

By reference: gauge (versus atmosphere), absolute (versus vacuum), and differential (between two points). The SI-702 is a gauge high-pressure transducer, with sealing variants chosen to suit the medium.

What are the four types of transducers?

In process instrumentation the four common measurands are pressure, temperature, level, and flow; a transducer converts each into a signal. This product is the pressure transducer, built for the high-pressure end.

How do you test a high pressure transducer?

Apply a known reference pressure from a deadweight tester or calibrated pump and compare the output against the expected 4–20 mA at several points across the range, checking zero and span. At high pressure use rated test equipment and follow safe practice; we can supply a calibration certificate.

Request a quote

Tell us the working pressure, the seal geometry and thread, the output signal and the medium temperature. We respond with a configured model, lead time and price, usually within one working day.