Help need with design of hydraulic control - drill rig

[CJONE]

The large pump section could be used to run the main motor, and when that's not running, to lift the carriage or run the winch to pick up a new pipe. A smaller pump section would be used to supply pressure when drilling to push down or up on carriage as needed. You want low flow here to minimize heat produced because some of the flow will go thru an adjustable pressure relief valve.

The flow control valve I linked to has a pressure relief valve built in. Maybe that could be set to limit the drill bit torque, or you could have another main relief valve.

When we set these rigs up we use a valve bank with a mid inlet section. The first set of valves run the pulldown and slow feed, this set of valves has a Vickers CT series flow/pressure control on it. Like you said it is low flow normally 10 GPM then it is combined with a 30 gpm circuit for the fast approach. The slow speed is just 10gpm and the heat generated is minimal for the size of the system. But like was stated we are not talking about a 2k system, the valve bank alone is over 2k. CJ

 

[JRobyn]

B-I-L typically only drilled to a max of 20 or 30 ft for blasting, but once drilled some "test" wells for us using a 3-1/2" bit down to about 120ft. When he did, he quickly found that UP force is an important consideration when drilling deeper bores. Shale and mud layers down about 40ft shifted just enough that he almost jammed and lost an expensive bit and sections of drill rod. His rig was evidently weak on up force and the bit was not designed to cut on the upper surfaces. It took several hours of attempting to extract the string to finally get it out.

 

[crystallattice]

CJONE, if I understand correctly: valve bank is fed by two pumps, first section by a 10gpm pump through a pressure/flow valve, then the section after the mid section is fed by a 30gpm pump, so if slow speed is not used the last section is fed by 40gpm? This would mean you have two levers to control the same function, one before the mid section and one after? Parallel control of the same component?

It sounds like you know how a proper rig should work! Do they have torque/pressure + speed/flow control on the rotary head or just speed? I was told by another guy that you need a decent amount of toque on the head, but from research it seems it is only needed to make up the joints and not really for drilling, I'm worried that too much torque will just break off the drill bit tungsten hence the need for control, but it might be redundant. From your explanation, it sounds like the down feed speed/force and the rotary torque/speed can't be adjusted independently, everything just moves slower/less powerful?

Would you perhaps have a link/model number of the Vickers valve you referred to? The ones I've found looks like a balanced piston relief valve.

So in my setup, I would use: balanced piston relief valve -> flow control (without internal relief) -> lever valve -> hydraulic motor. That way speed and torque is controlled in both directions. If fed by low gpm pump heating is limited during standstill as it is only going through balanced piston relief valve back to tank (if closed centre spool is used), right? Second section(not sure if it has to have a mid section of if two separate mono blocks can be used), fed by high gpm pump is all open centre, so fast operation of devices will affect each other if used simultaneously, but not much of an issue as this will not really happen, oil flows back to tank unrestricted(virtually) so no heating is happening.

I just saw a video on the net and they used FESTO fluid sim, I'm downloading the demo now...


JRobyn, this sounds familiar, this other guy still has a hammer and drill rod stuck down a hole! It would seem that the limitation is not on the drill/hammer but rather on the pullback force of the rig. So if you were to use the small drill/hammer on a big rig you should be able to go much further, say 300ft or is the drill rod diameter vs its total length starting to become a problem?

 

[jenkinsph]

crystallattice,
What is the maximum depth you are planning for? What size hole and drill pipe are you using? Do you have to install casing and if so what is the maximum size?

 

[crystallattice]

The idea was to build a rig to drill a standard 6" hole, install 5"-5 1/2" casing and fit a standard 4" pump. Unfortunately the compressor needed to drill a 6" hole is somewhat out of my price range, so the idea was to drill a 1" or 2" hole with a rented tow behind compressor and fit a surface pump, after making enough money then buy the right compressor and do things properly. Holes here can range from 7m-140m+, I would obviously target the areas with the shallow water first. In most cases it is only a few, 5-10m, of loose ground/clay then it is usually Table mountain sandstone, so a casing to the bottom is not really needed I suppose. If only I had enough money for that 25Bar 1000CFM Atlas Copco......

 

[CJONE]

CJONE, if I understand correctly: valve bank is fed by two pumps, first section by a 10gpm pump through a pressure/flow valve, then the section after the mid section is fed by a 30gpm pump, so if slow speed is not used the last section is fed by 40gpm? This would mean you have two levers to control the same function, one before the mid section and one after? Parallel control of the same component?

It sounds like you know how a proper rig should work! Do they have torque/pressure + speed/flow control on the rotary head or just speed? I was told by another guy that you need a decent amount of toque on the head, but from research it seems it is only needed to make up the joints and not really for drilling, I'm worried that too much torque will just break off the drill bit tungsten hence the need for control, but it might be redundant. From your explanation, it sounds like the down feed speed/force and the rotary torque/speed can't be adjusted independently, everything just moves slower/less powerful?

Would you perhaps have a link/model number of the Vickers valve you referred to? The ones I've found looks like a balanced piston relief valve.

So in my setup, I would use: balanced piston relief valve -> flow control (without internal relief) -> lever valve -> hydraulic motor. That way speed and torque is controlled in both directions. If fed by low gpm pump heating is limited during standstill as it is only going through balanced piston relief valve back to tank (if closed centre spool is used), right? Second section(not sure if it has to have a mid section of if two separate mono blocks can be used), fed by high gpm pump is all open centre, so fast operation of devices will affect each other if used simultaneously, but not much of an issue as this will not really happen, oil flows back to tank unrestricted(virtually) so no heating is happening.

I just saw a video on the net and they used FESTO fluid sim, I'm downloading the demo now...


JRobyn, this sounds familiar, this other guy still has a hammer and drill rod stuck down a hole! It would seem that the limitation is not on the drill/hammer but rather on the pullback force of the rig. So if you were to use the small drill/hammer on a big rig you should be able to go much further, say 300ft or is the drill rod diameter vs its total length starting to become a problem?

All the rigs I set up use a Hydrostat for the pump on the drill head. That way you have unlimited speed control from 0-max rpm. I either use a modified Eaton motor relief block with adjustable pressure range [torque] in forward and a preset relief in reverse that controlls max pressure in reverse. If the customer wants to get fancy I will rig a adjustable pressure control at the panel for forward torque. Yes on the valve bank with 2 inlets. The center is called a mid inlet. When you are not using the first set of valves it flows through the mid inlet and can be combined with the second set of valves for fast approach or high GPM requirements like winches and such. You can be using the pulldown/slow feed and still use the high speed set of valves separately from each other. Yes it is fed by at least a 2 section pump. Look up CT-06-b Vickers relief. These can be had for the 175 range from the aftermarket, put it where you can adjust it and you will not need to buy a remote pilot for it. Lots of money $$$ I do a lot with the smaller IR TH60's and Schramm water well rigs. Then when the oilfields are busy the top drives always need work, have 4 motors and a couple of hydrostats in right now. Fun fun. Any questions just ask and I will try to help. CJ