Bottle jack with pressure guage port in the UK?

[birchy]

You could probably use a load cell or strain gauge to measure to the pressure. Then you wouldn't need a special jack. Maybe you can utilise something like this: http://www.amazon.co.uk/Lincos-Hydra.../dp/B009M3SDN2

[Inquisitor]

Hi Birchy,

Thanks, for the suggestion and the link. I'm coming around to the idea that I'll have to use a system such as you suggest. It's just that (can we swear on here?) it annoys me greatly that every time I look at a project such as this there's something in the USA that's ideal for the job at a fraction of the price of a less suitable alternative that's all we can get here, assuming there is even an alternative available here at all.



Anyway, what I'm doing is hooking up a transducer (with a home brew USB interface) into a hydraulic line and using it with a ram and pump that I've borrowed for now so that I can concentrate on the rest of the system. There's plenty of other things to deal with :-)

For the record here's what I've considered so far:

Using a bottle jack and tapping it myself, cheap if I manage it but time consuming and prone to failure (will I get a jack that will dismantle, will I damage while taking it apart, will I introduce a weak spot that will fail...).

Using a bottle jack and using an existing hole, e.g. the release valve or safety valve! I've found a source of bottle jacks that come with an internal diagram now so I know how they operate and what's inside. The release valve would require a bit of precession engineering I think. The safety valve, apart from the obvious drawback of the potential for serious injury, would probably require the jack to be taken apart anyway to clean it out after I'd finished tinkering.

Using a bottle jack with a load cell, easy but the cost is in the region of getting the pump, ram and transducer etc. and then there's the extra mechanics to take care of too. I have considered using a system of lever and cheaper load cells but it's too much hassle.

Using an air cushion (air cushion jack, inner tubes or self built cushion), not outside the realms of possibility but the accuracy would be bad and the precision may be inadequate too.

Using a pneumatic ram, can't get one that will do the job directly for less than the cost the whole hydraulic system put together. I have considered using a smaller ram and a system of levers but there is too much to go wrong.

Using small load cells on my pressing plates, possibly a good solution but I'd need to experiment with a system that applies a known amount of force to get it calibrated which takes me back to step one :-)


If I get this thing working I intend to share the details so that others can benefit from it too, for that reason I want to keep the built as simple and cheap as possible (the bias being towards simple in the case of conflict).