Oil Tank Security

[edenbridge]

This thread may not prompt just electronic solutions, but I figured this was the best section to post in.

We've got ourselves a 1400 litre single-skin plastic tank, and we had originally planned to place it in a boarded/fenced enclosure alongside the driveway. However, with the rising cost of fuel thefts from oil tanks are becoming more common, especially in our normally crime-free area of Norfolk.

So we've elected to position the tank further back alongside the garage, but let's face it, even the most determined criminal is going to find a way to get to it. And it seems they're not to concerned about the environmental consequences of their theft - many ignore padlocks on the filler cap and drill a hole straight through the side of the tank, sometimes spilling thousands of litres of fuel in the process.

I'm currently digging the base for the concrete slab, and was wondering if there were any ideas or innovations I could include at this stage.

I'm open to suggestions, even the wacky ones, but the general brief is:
- The tank must still be accessible by the tanker driver.
- Any sensors/trip wire etc do not want to be constantly activated by pigeons or other wildlife.
- Above all, simple and cost effective!

I look forward to kicking some ideas around!

 

[breezer]

Build a brick wall with a door in the wall round it. have a digi lock on the door, tell the delivery co the number.

put signs up

"septic tank"

 

[edenbridge]

I like your idea of "septic tank" signs!

Giving out the combination to the delivery company could be a worry; I've read on another forum that many people have had their oil stolen within a week of delivery.

Either the theives are following the tanker to see where it goes or, perhaps worse, someone at the oil company is tipping them off!

 

[TicklyT]

Don't padlock the filler, but put a tilt sensor or light sensor under it. Open the lid and it suddenly gets very noisy!

Or something to monitor the rate the level drops at?. If it starts dropping faster than it should, then somebody's pinching it!

First thought is something along the lines of an air pressure switch, but with both sides of the diaphragm connected together and to a dip tube. A plug with a very small hole (a gas pilot light jet or a carburettor jet?) in one tube would allow the pressures to equalise if the level drops slowly, but trip the switch if it drops too quickly.

 

[edenbridge]

Sorry, it's been a while since I've looked on here, but thanks for your respnse, TicklyT.

I was also thinking along the lines of a rate sensor, but just didn't know how to go about it. Something like a ballcock or some other float was as far as I got, but your idea is no doubt more sensitive.

Some sort of tremble switch on the lid was on the table, but putting it on the inside is probably the way to go.

I was also thinking of some form of membrane or mesh to wrap around the tank, so that if punctured it would detect a change in the resistance and set off the alarm. This is probably getting too sophisticated and expensive, and probably cheaper to opt for a double-skin tank!!

With necessity being the mother of invention, how long will it be before we see these ideas on Dragons' Den??!!