You could have automatic chemical delivery without pumps if you suspend the chemical up high and use a solenoid to open and close the right valves. From what I have seen it would be pretty simple to program a PIC Micro to operate all these solenoids. You could even raise and lower the tank with the right motors. Maybe a stepper motor pulling a cable to raise the arm. That would be more robust than the Jobo arm. Then you can free up your technicians to do other work as the fully automated processor does the film.
Having worked a metal lathe I would say it a bit overkill for the process. It is reversible though. I think most attempts at reusing an existing appliance will fail. Better to try to find a good standardised motor. Like the Bosch one. Using a lathe would be extremely wasteful and hence expensive.
I was sketching something like this for my own private use. I had this weird idea of using a strong neodym magnet as a coupling for my SS tanks. Probably no good for the jobo tanks though.
If you plan to go down the microcontroller route I would give you the advice to not use any made-in-china lo-fi models. Try to use industrial standard ones instead. I worked as a service technician for a while, and there is a certain quality difference.
Bob, nearly anybody that works with industrial automation can do this. A servo or stepper motor can be driven at any speed (and reversed quite readily) by a PLC (which would also handle all the automation tasks as well) No single task is really that difficult to re-engineer, integrating them together almost demands the use of a PLC or automation computer. I'd love to tackle a project like this, but I've returned to school full time to complete my degree and spare time is scant. I'd be happy to be a person to bounce ideas off of, and can make a few inquiries to some of the CNC people I know in the area, as I sold off all my automation inventory a few years ago.
Originally Posted by paul ewins
*edit* Seeing the above responses, I'd suggest a small PLC (try AutomationDirect.com for inexpensive units) driving a stepper (www.geckodrive.com for drivers) and a little bit of wiring, you can add a temperature controller, solid state relay for the circ. pump., etc. Any industrial grade component would be miles more reliable than what JOBO used. As far as dispensing chemistry, Wing-Lynch's approach is ingenious, uses compressed air or nitrogen and only requires off the shelf pneumatic control solenoids. Pretty easy to create from scratch. I have several spare tanks here, if you need pics and ideas.
I can't thank you enough for all the new ideas , I am starting to envision a way to quickly add the tempered chemicals via a pump like the replenisher pumps on my processors , I need to get 1-2 litres , depending upon tank size quickly into the tank , lets say faster than one could pour.
We will bounce the ideas off this group to see any flaws, improvements or observations after we meet later this month.
As to filling, you could have a system where the chems are gravity fed via a large diameter pipe into the tank, which is regulated by a four-way stopcock type valve. You might have to have the valve custom made, but it would be far cheaper than a repair to or replacement with a new Jobo.
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Not so if you are building on an inexpensive woodturning lathe. There are some models that cost less new than you can build a platform yourself. It's pretty common for the pulley compartment to have a hatch on the back to facilitate changing speeds, you can mount an outboard motor on quite a few of these to replace the stock motor, I've seen a few for sale reworked like this. A water bath can be mounted on the bed of the lathe, depth depending on the size of the lathe. A 10 inch lathe like I have would allow 5 inches of clearance from the spindle to the bed, plenty of room for a 4 inch deep tray. Harbour Freight sells a really cheap lathe with a 14 inch swing which would get you a good six inch deep tank. A little searching on Craigslist or the local want ads might come up with some suitable candidates.
Originally Posted by olleorama
I should mention here Scott that the chems need to be tempered so I was thinking stainless steel holding tanks in a water bath with a sump pump or bellows like replenisher pump drawing from the stainless steel tanks at temperature.
Originally Posted by TheFlyingCamera
Oh I know about the VW in-line waterpump motor. I have seen one in action before. I was referring to the actual motor that rotates the drum. Allegedly, and I read this on some other website, that motor is a BMW windshield wiper motor.
Originally Posted by Bob Carnie
I was curious if everyone that was considering stepper motors would want to know what motor that was from and if replacements were available.
are you looking to just build a base that has a belt drive to the motor? I'd image that if you have different sized tanks (2500 vs 1500 series), you could just have some riser-type blocks made, so that you could have the same wheels underneath the tank for both, kind of like the Jobo setup. just make em out of stainless, not cheapo plastic(like Jobo)...
if you're just going to pour manually, you can take the tanks off of the base(tanks in waterbath during rotation), dump the chems, put back on the base(so it begins turning again), and have a 3/4" flexible tube attached to a large funnel(like a beer bong basically )
then you wouldn't have to worry about holding a flexible tube, allowing you to pour the chems(from the tempering bath), either a separate unit(like the Jobo one), with chems in stainless beakers or the Jobo 1ltr/2ltr chem bottles.
if you had a separate tempering bath from the unit, it would allow you to heat up the chemicals much more quickly, meanwhile having the tempered water in the rotating base, getting warmed up. if you had 140deg F water heating up the chems, with your 101F (accounting for plastic as Jobo users do know )....
sorry I'm rambling, I just really would like to have a part in this project if I could, cause I'm really interested in seeing this project come about the way you need it too. its fun too!
I do not think that a WW motor is adequate for this type of application. I put 28,000 hours on one of my processor drive motors, only replacing the brushes once. A lot of good designs are crapped on by using parts to keep the profit margin as high as possible. And making work for service personnel.
Why are there no speaker jacks on a stereo camera?