flow meter+solenoid valve+thermometer

Hi everybody! I would like to start working on a project which involves controlling the temperature and flow of water in a pipe, by regulating the flow of warm/cold water into it. In order to do so, I need to be able to measure temperature and water flow in both cold and warm water pipes, and to regulate the flow in both. I've seen solenoid valves, flow meters and thermometers, but do you know of any product which combines the three? (I'm talking about household-type piping, so that's more or less the scale). If there is no such product, is there a relatively cheap thermometer designed for measuring water in a pipe? (I'm trying to avoid buying a normal thermometer and drilling it into a pipe, if that's possible).

Thank you for your help!

Is the water enclosed in the pipe for the entire system, or does the water exit the pipe anywhere giving you access to it?

cbrum11: Is the water enclosed in the pipe for the entire system, or does the water exit the pipe anywhere giving you access to it?

As far as my system is concerned, the water never flows out. I can add more piping in the way (i.e. a flow meter in the middle of the pipe), but the water must remain enclosed for the entire process

They do make solenoid valves that do everything you want... however, for most people, they're prohibitively expensive.

The cheaper (and I mean MUCH cheaper route) would be to combine three separate sensors. Unless you're looking for very sensitive readings, I'd go with an RTD (as I find them most accurate).

Instead of an all three combination, you might be able to find a combination flow meter/temperature sensor and then add a solenoid separately?

The flow meter/temperature combination seems a bit more economically in reach than the 3 for 1 combination. Although 3 separate sensors would still be considerably cheaper.

If you' don't have access to the water the only way I can think of to get the temperature would be with some fancy heat transfer math if you know the conductive coefficient of the pipe. That along with a few verifying experiments would probably get you where you wanted to go.

Not sure how complex you're trying to get though...

-Chase

Thanks for the input. I think that for the proof of concept I'll go with three separate sensors then. For the temperature measurement I don't think I'll go with measuring outside temperature, as the surrounding temperature varies and that would be a headache. Worst comes to worst, I'll drill into a pipe and create a DIY pipe-thermometer using a normal waterproof thermometer, I just thought there must be such a product available.

If you want to do anything with the temperature, like change flow rates or get alerts when certain values are reached... you're going to need to interface your temp measuring device with the Arduino (in other words, a separate thermometer wouldn't be a good idea).

Some different electronic temperature measuring sensors include:

RTD's Thermistors Thermocouples Optical Sensors

All have their benefits and drawbacks... most come in versions that are meant to be placed inside a liquid or pipe. As mentioned earlier, I like the RTD's.

Obviously I meant to use a thermometer which can interface with an Arduino. Aren't RTD's, thermistors and the like all considered types of thermometers? (an English moment for the none-native-English-speaker :D )

RTD's do look like the best option. I'll give it a go then. Thanks a lot!

normal waterproof thermometer

For being a non-native English speaker, your English is pretty flawless. The word “normal” just threw me off.

Best of luck!

-Chase

Why, thank you! :grin:

shayelk: I would like to start working on a project which involves controlling the temperature and flow of water in a pipe, by regulating the flow of warm/cold water into it. In order to do so, I need to be able to measure temperature and water flow in both cold and warm water pipes, and to regulate the flow in both.

So what is the real objective? It sounds like you are just trying to regulate temperature by mixture. If that is the case I don't think you need to measure the water flow. Arduino just measures the temp and adds hot water as required.

I've seen solenoid valves, flow meters and thermometers, but do you know of any product which combines the three? (I'm talking about household-type piping, so that's more or less the scale)

The individual components are very cheap. If a combined device is available, it will probably be quite expensive.

If there is no such product, is there a relatively cheap thermometer designed for measuring water in a pipe? (I'm trying to avoid buying a normal thermometer and drilling it into a pipe, if that's possible)

You can hardly go wrong using a DS18B20. It is only a few dollars, accurate, has no need for calibration, is well-supported on this forum, and very easy to use.

There is no need to drill the pipe. You can use a thermowell, which is normal practice for pressure systems, or simply lay it on the pipe under an insulating sleeve in some thermal paste or even silicon. If your pipework is Pex, it would be a good idea to let in a short section of copper and fix the sensor to that. This would make life easier for the Arduino.

Nick_Pyner: So what is the real objective? It sounds like you are just trying to regulate temperature by mixture. If that is the case I don't think you need to measure the water flow. Arduino just measures the temp and adds hit water as required.

I need to regulate both temperature AND flow in the output pipe, so I'm afraid measuring water flow is crucial.

Nick_Pyner: You can hardly go wrong using a DS18B20. It is only a few dollars, accurate, has no need for calibration, is well-supported on this forum, and very easy to use.

There is no need to drill the pipe. You can use a thermowell, which is normal practice for pressure systems, or simply lay it on the pipe under an insulating sleeve in some thermal paste or even silicon. If your pipework is Pex, it would be a good idea to let in a short section of copper and fix the sensor to that. This would make life easier for the Arduino.

A thermowell is a great idea (didn't know they existed until your comment made me google it), thanks!