Which chip measurement temperature can i used under water?

[chithanh04dt2]

Hi,
I need to know the temperature of water cooling in spindle for CNC machine, can i used LM35? if not, what IC i can used underwater.

[Okada]

What will be the temperature range you want to measure? If it is from -55 degree C to +150 degree C then you can use LM35. You have to insulate the leads of the LM35 or any other sensor properly.

[Ichan]

I need to know the temperature of water cooling in spindle for CNC machine, can i used LM35? if not, what IC i can used underwater.

Yes you can use LM35 as long as you isolate the leads from the water.

But, doesn't it better (and easier) to measure the temperature of the spindle it self?

-ichan

[Ganymed]

Or you take a thermocouple element like NiCr-Ni wire.
It's easier to isulate.

[solutions]

I suspect you are talking about coolant used in machining that happens to run through the spindle, vs "water", and has fine metal particles in it.

Anyway, if you implement some of the cowboy ideas here, let us know which CNC's will have it so we can steer clear of being electrocuted by them  

READ THE DATA SHEET FIRST   READ THE DATA SHEET FIRST   READ THE DATA SHEET FIRST   READ THE DATA SHEET FIRST   READ THE DATA SHEET FIRST   READ THE DATA SHEET FIRST

http://www.ti.com/lit/gpn/lm35

"As with any IC, the LM35 and accompanying wiring and circuits must be kept insulated and dry, to avoid leakage and corrosion."

AND

" the LM35 can be mounted inside a sealed-end metal tube, and can then be dipped into a bath or screwed into a threaded hole in a tank"

 

Use an automotive sensor and you're done.

[jiakoub]

check this its cheap and waterproof
http://www.ebay.com/itm/1pcs-DS18B20-Waterproof-Digital-Thermal-Probe-or-Sensor-GOOD-/230908052812?pt=LH_DefaultDomain_0&hash=item35c331454c

[gmua]

There's a nice tutorial on www.instructables.com on how to Waterproof a LM35 Temperature Sensor

http://www.instructables.com/id/Waterproof-a-LM35-Temperature-Sensor/

Hope this helps...

[Gallymimu]

As mentioned above,

use an insulated temperature probe, or an insulated thermistor, or an insulated thermocouple.

If you want to use an LM35 you can submerge the whole thing and wires in potting compound or even plastidip, but your thermal response will be slower.

[bigtoy]

Buy it in the TO-46 (metal can) package, pot it with whatever plastic or epoxy you prefer, but leave the top of the can exposed. That way you still get good thermal connection to the water (and fast response time).

[f22kma]

Thermopockets are usually quite expensive.

If you need a cheap option, we sometimes use 1/4" stainless tube brazed to a 1/4" bulkhead fitting and then braze a small rod into the tube tip to seal.

With a chip sensor and some silver loaded thermal transfer compound inserted into the tube, the performance should be more than adequate for CNC machine coolant monitoring.

You could also add a "T" fitting to the coolant supply line (with the sensor inserted into the branch of the "T") for a fully reversible installation that doesn't require modification of the CNC machine itself.

[galaxy]

my fav. is  SMT160-30-TO-18
metal, so you can seal it in a metal case without losing quick response,
digital outout, so you can have long wires without losing your signal (PWM)

regards

[sfiga69]

If you want to save money with DS18B20 Waterproof, watch these:
http://www.aliexpress.com/item/waterproof-temperature-sensor-Probe-DS18B20/758253787.html
I have taken them and work fine

[metal]

I agree with that, they are just excellent.