Sensors, Pressure Temperature, Dirty Hot Gas

Any vendor, distributor can help you with everything but the low pressure gauge.

Low pressure gauges like that use either delicate bellows are very large elastomeric diaphragms that will not deal well with heat or dirt.

By the time you pay for something the measures in that mechanically and somewhat reliably, you're probably better off with a local display for the electronic pressure transmitter.

You'll need to isolate the pressure transmitter from the heat with impulse tubing or a remote seal.

There's a button above labeled "Products & Supplies". It takes you to the IHS search engine for products. You obviously can also use other search engines, even the one that sounds like a very big number.

You will probably have to deal with some logistics. You do not indicate where you or these dirty hot gasses reside. You might have to pay some import duties and shipping costs.

This will of course depend a lot on what kind of "dirt" is in this gas. Common incomplete burning hydrocarbon particles (aka soot) could probably be sensed safely by many automotive exhaust gas sensors. Dirty gasses from fuel production, biophamaceuticals, food production, insecticide production and a myriad of other possibilities will have their own concerns.

In your case, you might be better off hiring somebody that knows the field instead of asking a bunch of strangers that know nothing of your situation how to do this job.

Have a lazy day.

Simple. Instrumentation vendors. It's time to Google their phone numbers and discuss the applications with them directly.