# Pressure sensor 125°C, 3 bar

I'm trying to find a small pressure sensor for an environment that will be between 1 and 3 bar absolute, 10 to 125°C, and 100% humidity.

By small I mean a port that's no larger than about 1/4" (sorry for mixing unit systems). Ideally I'd like to have a digital interface but it's not critical. And full temperature compensation would be wonderful, but if I have to I can calibrate across temperature and pressure.

What's my best option? I'd love to get away for no more than about $50, but I can probably spend around$150 if I have to. Is this possible?

Gold Member
Is the ambient operating environment temperature reach as high as 125°C or is that the temperature of a fluid or gas being sensed.

Both. The sensor will be mounted on the exterior of a metal vessel which will contain the hot vapor. So the vessel itself will be close to the same temperature. But the environment outside the vessel will be room temperature and normal humidity.

Asymptotic
Ideally I'd like to have a digital interface but it's not critical.
How do you mean? Digital as in on/off (above/below a setpoint) - that is, a pressure switch, or an analog pressure transducer with the output coded into some manner of digital format?

125°C wetted is just barely do-able in an affordable analog pressure sensor. Specs for ProSense series pressure sensors as an example.

How do you mean? Digital as in on/off (above/below a setpoint) - that is, a pressure switch, or an analog pressure transducer with the output coded into some manner of digital format?

125°C wetted is just barely do-able in an affordable analog pressure sensor. Specs for ProSense series pressure sensors as an example.

I meant a digital interface for reading the sensor would be the simplest but it is by no means a requirement.

Thanks for the link. I was hoping something less expensive might be available but I kind of suspected that would not be the case.

Gold Member
If you are not reading fast dynamic changes of pressure then the actual sensor can be mounted away from the pressure vessel and connected by a suitable shaped tube .

Most commonly a U tube with the outer leg longer than the vessel connection leg is used so that gauge is above the level of the actual port . There are several alternative configurations though .

Common practice . First devised in the early days of steam technology for connecting mechanical pressure gauges to boilers .

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Asymptotic
If you are not reading fast dynamic changes of pressure then the actual sensor can be mounted away from the pressure vessel and connected by a suitable shaped tube .

Most commonly a U tube with the outer leg longer than the vessel connection leg is used so that gauge is above the level of the actual port . There are several alternative configurations though .

Common practice . First devised in the early days of steam technology for connecting mechanical pressure gauges to boilers .

That was my first thought, to use a pigtail kind of isolation. But I worry this will perturb the system significantly. It's a fairly small chamber.