Hello all what a grate forum you have

Hi guys and girls. Wish I could say I had the head for this sort of stuff but sadly I don't. I have joined the forum in serch of some advice on how I could go about controling water flow with temperature. I am a home beer brewer and my friends and I want to take our hobby to a new level and try and add some automation to it. So the first step we want to try is to control our water flow. So we would want to speed up the flow or slow it down depending on the temp of the water. Higher the temp faster the flow and so on. So we have a pump that we use in our system but we need that to be running at full speed all the time and then that liquid is pumped around our system to diffrent parts and back again. So I was wondering what you thing of a servo that opens and closes a valve ??. Then that valve is controlled by a temp sensor.

Kareeves:
Hi guys and girls. Wish I could say I had the head for this sort of stuff but sadly I don’t. I have joined the forum in serch of some advice on how I could go about controling water flow with temperature. I am a home beer brewer and my friends and I want to take our hobby to a new level and try and add some automation to it. So the first step we want to try is to control our water flow.
So we would want to speed up the flow or slow it down depending on the temp of the water. Higher the temp faster the flow and so on.
So we have a pump that we use in our system but we need that to be running at full speed all the time and then that liquid is pumped around our system to diffrent parts and back again. So I was wondering what you thing of a servo that opens and closes a valve ??. Then that valve is controlled by a temp sensor.

In the process control world that would be called a cascade control loop, where the output of the temperature controller drives the setpoint input of a flow controller. In practice you get both controllers working and tuned individually before switching them to a master/slave cascade mode. I would think that your first step would be to locate the well made PID library and work on getting a simple example working.

http://playground.arduino.cc/Code/PIDLibrary

Hi and welcome,

There are solenoid valves like this, but they may be overkill for your needs. Unfortunately they are either on or off. They run on 12V too which is a pain. Ideally a solution would use small servos like this to control a small valve like this somehow. This would allow more control of the flow because the servo could partially open the valve.

For temp sensing, consider ds18b20. Multiple sensors can be daisy-chained on a single pair of wires, yet the Arduino can read each individually. They come in waterproof versions too like these.

Paul

Is it possible to flow the water through soft plastic pipes and use a servo to pinch the pipe to control the flow?

...R

Thanks for your reply's guys it has given me lots to think about. We all ready use PID controllers with our home brewing so I am wondering if I could just use a PID to control a servo to open and close a valve. Sadly a solenoid is no good for this because I have no flow control.

I don't like the thought of trying to control my water flow by using a servo to pinch a soft hose I don't think I would get the sort of control I need. I think it would work on small applications but not on a job like what I need.

This is the type of valve I need to control http://www.irrigationstore.com.au/Gate-Valves and it needs to be done by temp. To help you understand the application. We have a steam pipe with a water jacket I need to control the flow of water in that jacket. So if the temp is set a x amount and it goes 5 above deges it opens and if it goes 5 blow its slows down the flow.

Do a Google search for "electric ball valve" and click on "Images". Insure you are sitting down with a beer when you check out the prices. Whew!!

Sound like a Still!

PS. Thanks for the comments about this forum. Good to know that the ashes from the fire can pass through here and be collected in a box for later disposal! ;)

PPS. That link you posted doesn't seem to work.

BTW, if you plan on drinking the beer you are brewing (or liquor you are stilling), insure the valve is food grade. That adds to the already high cost. I wouldn't want you to accidentally poison yourself with lead or some other heavy metal or chemical leaching out of the valve.

PaulRB:
Sound like a Still!

PS. Thanks for the comments about this forum. Good to know that the ashes from the fire can pass through here and be collected in a box for later disposal! :wink:

:smiley:
Maybe give rise to the Phoenix?

Ray

Have a look at this: http://www.belimo.co.uk/CH/EN/News/Product/index.cfm?#EV14

has integrated temperature measuring and all sorts of intelligent bits. I can't say I'm sure what the cost would be, but could find out easily as we are a Belimo dealer. We would normally use a 0-10v controller version and talk to it via a PLC which already controls lots of other things in our data centre, those valves are sub £100: http://www.belimo.co.uk/pdf/e/Overview_E.pdf

In terms of control, it should be fairly simple to get an arduino to read a temperature value from a DS18B20 or similar and use that to control a valve...

Can you give more details about the temperature range you need to control to, and the flow rates you're dealing with? From what you've said so far this sounds like the sort of thing that might be better addressed by a wax stat rather than a microcontroller.

PeterH: Can you give more details about the temperature range you need to control to, and the flow rates you're dealing with? From what you've said so far this sounds like the sort of thing that might be better addressed by a wax stat rather than a microcontroller.

Hi and thanks for your reply. The typical temps range from 50c up to 100c and as for the flow rates well that will very. The reason being different size rigs. I am a hobby brewer but others that are interested in this are commercial. Your probably asking why a commercial company would be interested in something like this that has been made at home but a lot of these small commercial brewer's are built on good old home DIY stuff.

What ever line of approach I take I need to build it with off the shelf parts that any one can buy and at fair prices. Luckily we have ebay and ebay can make for cheap shopping sometimes.

Hmmm. That's a pretty wide temperature range and would make it tricky to achieve with just a passive stat.

The next most obvious approach would be to design your circuit so that you can vary the pump speed to control the flow rate. Your original post said that you need the pump to be running at full speed all the time but can you double-check that assumption? I don't know what your circuit is like but it seems to me that with a bit of ingenuity you may be able to redesign it so that temperature can be controlled with pump speed, even if you end up having to add another pump to achieve that.