Expanding braking system - Any DIY ideas?
powellite
Posts: 3
Hello;
I have an approximate 3 inch diameter steel pipe (HQ size) in a vertical position. In the center of the pipe is a 1/8 inch steel cable. The vertical depth of the pipe is 500 feet. It's a historic / old drill hole that I need to acquire data from.
At this point, I'm just requesting some random "how-to" concepts. I' want to build a small sled / dolly that I want to run vertically down X feet using the 1/8 inch stationary steel cable as a "trolly line". I'd prefer an automated system so I had planned on using a Parallax microprocessor to control the on-board systems (whatever they might be - maybe up / down / gather info commands). And, most probably an Xbee to "talk" to a possible surface controller that would pass commands to the dolly. I'd probably include a gyro unit because the acquired data might be useful.
Once the dolly travels via rollers / wheels (??) to a certain predetermined depth - say 287 feet, I want it to stop (or I tell it to stop), then anchor / hold itself in place while I initialize a cutting tool to score the outer surface and gather information for me. What would be useful to hold itself in place? Small braking shoes like those in a car, expandable rubber tube / tire that perhaps was controlled by a small CO2 supply? Other ideas??
At this point I'm just searching for ideas. Everything is mostly conceptual at this point. Maybe someone has built or seen a horizontal unit that can complete similar data gathering tasks?
Thank you.
Dan (powellite)
I have an approximate 3 inch diameter steel pipe (HQ size) in a vertical position. In the center of the pipe is a 1/8 inch steel cable. The vertical depth of the pipe is 500 feet. It's a historic / old drill hole that I need to acquire data from.
At this point, I'm just requesting some random "how-to" concepts. I' want to build a small sled / dolly that I want to run vertically down X feet using the 1/8 inch stationary steel cable as a "trolly line". I'd prefer an automated system so I had planned on using a Parallax microprocessor to control the on-board systems (whatever they might be - maybe up / down / gather info commands). And, most probably an Xbee to "talk" to a possible surface controller that would pass commands to the dolly. I'd probably include a gyro unit because the acquired data might be useful.
Once the dolly travels via rollers / wheels (??) to a certain predetermined depth - say 287 feet, I want it to stop (or I tell it to stop), then anchor / hold itself in place while I initialize a cutting tool to score the outer surface and gather information for me. What would be useful to hold itself in place? Small braking shoes like those in a car, expandable rubber tube / tire that perhaps was controlled by a small CO2 supply? Other ideas??
At this point I'm just searching for ideas. Everything is mostly conceptual at this point. Maybe someone has built or seen a horizontal unit that can complete similar data gathering tasks?
Thank you.
Dan (powellite)
Comments
You might look into how oil well "loggers" do their business. Generally, they lower a probe down a borehole with an armored cable that supplies power and reads signals. They lower the probe to the bottom of the hole with its metal fingers retracted, then open up the fingers so the probe is held somewhat steady in the hole via friction. Then they start winching up the cable and keep track of the depth via how much cable they have paid out/winched up.
In any case, you'll probably want your retractable mooring system to "fail safe" by retracting automatically via a spring or something when it is powered down, otherwise a power or control failure could leave the device stuck in the hole forever.
It really depends on how much mechanical skills you have, and what sort of machine shop tools you can use.
Try looking here for inspiration: http://servocity.com/
(Valve 1, Normally Open solenoid valve)
(Air Tank)
(Valve 2, Normally Open solenoid valve)----(Piston+Spring system)---(Pad touching borehole)
Both Valve 1 and Valve 2 need power to remain closed. To actuate your Piston+Spring system, you de-power Valve 2 and allow pressure into the piston. When you want the piston to retract, you then de-power Valve 1 and let all the pressure out, so the piston retracts under the force of its spring. If your system loses all power, then both valve 1 and valve 2 will open up and your piston will be driven back by the force of the spring.
By using more valves and whatnot, you can make it more complicated so you can get multiple extensions on a single tank of air, but that's probably the simplest system that will fail safe, sorta.
The whole thing gets lowered and raised via a cable+rope that powers the probe and provides you with whatever data you're trying to retrieve.
the pipe. The legs need to be positioned to spread open from the bottom so that they tighten against
the pipe wall with gravity, and then releases when pulled upwards. I think it would help to have a heavy
fishing weight tethered with a piece of piano wire about 3 feet below your "logging device" to aid the expansion
of the legs against the pipe. Or weighted on the bottom of the "logging device."
The legs can be set to spring open after a micro releases them. The legs would remain deployed, and harmlessly
drag along side of the pipe for the assent.
To answer a few of the questions in the above discussion. I'm trying to come up with a better mousetrap - one more exact in term of down-hole measurements and data gathering at very specific depths.
It is a diamond drill pipe. HQ size - 96mm od / 63.5mm id. The conditions in the hole may be wet (damp) or dry. I like the electromagnet idea and the pressurized air controller system. Both are worth thinking more about. I can most certainly attach an electrical cable to the trolly to get power to a set of electromagnets which would hold the unit at the depth I select. Yes, the XBee is a bad idea due to potential interference but I can add another hard-line cable to the trolly to talk directly to the micro controller.
Thanks to everyone again.
Dan (powellite)
You may be able to get some ideas from a rope grab, which can be found here: http://www.millerfallprotection.com/fall-protection-products/connecting-devices/rope-grabs-and-vertical-lifelines.
Or, perhaps two small pieces of plate aluminum, with three wheels in between them, two idlers on one side of the rope, and a drive wheel on the other. Of course the drive wheel would be used for braking. Additionally, either the drive wheel or the idler wheels could be spring loaded, just in case the ride becomes a bit bumpy.
Bruce
use "Filing date: oldest," there are many practical examples.
That's a nice chunk of steel. Are you intending on measuring the drill pipe itself or the rock formation behind it? Mind if I ask what measurements you're taking? Did this drill pipe get stuck in the hole or what?