Level

Is this some sort of ketchup distillation process? Will tomato whiskey ever catch on?

No. You will need.an ultrasound distance sensor.

...which won't operate at <...vacuum...750mmHg...>; brilliant idea.

ok,....

So you want to see the level of the pulp in a tank under vacuum, there are a number of sensors that can do this. Sonic, Radar, the best and cheapest is a 4-20 mA probe or even a pressure transducer (if you know the weight of your pulp and its consistent).

I doubt a sonic sensor will work well in a vacuum.

ah crap..... your right...... In space no one can hear you scream

.

If no one can hear you, are you really screaming ?

your you're

pulp can't be called vacuum. perhaps air is being sucked. use ultrasonic sensor from bottom side and it will give reflection signal at the interface.

Radar probes.

Just use that sight glass on the side of the tank. All you have to do is walk up to the tank and read the level.

You need a capacitive proximity sensor with adjustable sensitivity, when properly setup it will "ignore" the tank walls and only give you a signal if tomato pulp is present.

Try Omron, they come in different flavors.

I don't think the capacitive proximity sensor is the good solution because this sensor is designed to detect the objects from a short distances max (22mm) in the clean and open environment (C proximity sensor is not recommended to use with tanks) if any drop of water or a liquid sticks on the surface of the sensor the sensor keeps giving an error signal and we can't grant that will not happen when the tomato pulp far from the sensor max 22mm inside a closed tank. i have tested C.p.sensor before for this case .the Ultrasonic level meter is recommended to use inside a closed tanks works good in a wide rang of temperature , pressure, and 50% humidity but i am not sure about the vacuum issue .i think use a water float valve switch is the best solution .

Not good. If the dielectric of the material varies, as it will if the material is being evaporated under vacuum, then the instrument will give false readings as the properties of the material change with time. Capacitance level is only good for fluids that don't vary in consistency, and should only be chosen if nothing else will do the job.

If the material is being evaporated is a pretty good assumption......... it could be deaerating?..... yet another assumption.

Yet not enough applicable information.

Quite. One might wonder what the Original Poster has done in the way of telephone research with potential suppliers before purchasing and installing something.

How often do you have to water a tomato sause plant?

Depends on how global climate change has effected your rain.

I wonder how much California fire damage coverage my homeowners insurance company has?

Is this what you mean?

If you really have a tomato sauce manufacturing facility, hire a competent instrumentation or process engineer to solve this problem, if there is one.

If the plant exists and has been running profitably leave it alone. If you want to squeeze more profit from this "plant", hire someone.

Otherwise, water as needed to assure no dead leaves.

You gonna put some meatballs in? Don't cook the pasta too long, just al dente. You a good boy jalCHOUDRY, comer here, I pinch you little cheek.

Ultrasonic is not suitable and is categorically off the list due to vacuum conditions.

Temperature was not mentioned. How hot is the liquid?

Steam tables will give the answer. Just look up the boiling temperature of water at <...750mmHg...vacuum...>.

Free Radar level meters are reliable and will read in a vacuum.

You could use a differential pressure cell, with the low-pressure side piped to the top of the tank above maximum liquid level. That gives liquid depth irrespective of gas pressure above the liquid.

Impulse pipe to the high-pressure side would likely block, but you can get them with a diaphragm flush with the tank wall.

>You could use a differential pressure cell

Maybe, maybe not.

The OP never replied to my request for the process temperature. And it isn't clear whether his 750mmHg vacuum is gauge or absolute.

Combine high vacuum at elevated temperature and remote seal diaphragms will pop outwards and destroy their functionality. Birds and bees, facts of Life.

The graph below (or one similar) is in the remote seal transmitter specifier's guide. It is usually ignored until a remote seal diaphragm transmitter dies and THEN it gets the attention it deserves:

This happens to be a Honeywell graph, but given that physics don't vary by manufacturer, the results are pretty much the same for all vendors.

Caveat Emptor.

Pulling a <...vacuum...> on <...tomato sause ...> will cause the water contained in it to boil until there is none left.

So this cannot be done without affecting end product quality.