Hi,

We are about to begin our end of year project for the first year of our apprenticeship. We have to design and build a portable device that can be connected to pipe work to measure yemperature and pressure of the product within (water). The device must be coupled to pipework to ensure no leakage of the product. It must not be powered by batteries alone. Budget £250

The questions we have if anyone would care to answer are:

We are using a DP cell to measure the pressure of the water, however this takes 24v DC. What would be the best way to power this? We were thinking of having rechargable batteries and solar panels of some kind which could also be charged by the mains?

We are also thinking of building our own thermometer, is this easy to do?

We also want to have a light that turns on when the volatge drops below a certain point, so we know the batteries need to be recharged etc? Can anyone help me with this?

Obviously we have the ideas in place (ish) but if anyone can help me as to implementing them that would be brilliant. Any help great little or small.

Cheers

 

Hmm, building a thermometer isn't hard, I would be more concerned about the pressure. Do you know of the ultrasonic debit meters?

 

No cant say I do, can you please explain? Were going to be using the following differential pressure cell:

https://www.honeywellprocess.com/en...mitters/st-3000-series-900/Pages/default.aspx

We have kinda been thrown in at the deep end but any help or advice is brilliant thank you

 

What is the cost of this cell? It looks fine actually, if it will provide you with all the sensors needed it's ok to go for it. The ultrasonic debit meters use the difference it frequency in order to determine the speed of a fluid flowing through a vessel (sound distributes slower in a liquid than in air), but not sure if it's suitable for your project in particular if you can just use tensoresistor. You can design step up transformer to get the 24 volts from a standard 12 volt accumulator. Rest is to chose a micro controller to process the data.

 

The device must be coupled to pipework to ensure no leakage of the product.

You need to define what you mean by this. Thermal wells in which to immerse a temperature probe are common in industrial pipework, as are taps for pressure sensors. But these are built into the process and only the probes and electronics are "portable". If you truly need non-invasive measurements that you can apply anywhere, it's a very different game. For instance, IR guns are commonly used to measure temperature in locations where a permanent probe installation isn't worth it.

 

Did you discuss the cell with the teacher? As you said that you are planing on using it, I decided it was suggested by the one who gave you the assignment. However tenzoresistors are not really portable, so if you want to design something really universal and portable it would be with ir sensor for the temperature measurement and maybe ultrasonic for the debit.