Looking for Electrical Cable w/High Tensil Strength

[ndzied1]

Hi all,

I'm looking for a cable the can work with a 4-20mA pressure transducer but that also has a high tensile strength so I can hang the transducer from the same cable down into a 2000 ft. deep well.

Oh, and I've been given a 1/4" limitation on the diameter of this job.... I actually have a sample cable where there is a single insulated center conductor wrapped in two layers of steel reinforcing strands. They used the center for one conductor and soldered/brazed to the outer steel strands for the other. (I can be > 1/4" diameter near the transducer but the cable is fed through a 1/4" hole.)

But I'm not sure that will meet the Class I Div I requirement that they are looking for (although maybe if the sensor itself is C1D1 then maybe???

I'm not actually very optimistic finding something but figured if anyone had seen something like this in the past, I'd find them here.

Thanks

 

[Christoff84]

I'm not too sure about resistance wise, but perhaps using co-ax or some form of BX? The problem with running any cable down a 2000 ft run is you probably want shielded, twisted pair and not some pieced together cable with high tensile strength.

Would it be possible to use something like 1/8" rigid pipe and have the wire running inside, let the pipe do the holding?

 

[leitmotif]

Hi all,

I'm looking for a cable the can work with a 4-20mA pressure transducer but that also has a high tensile strength so I can hang the transducer from the same cable down into a 2000 ft. deep well.

Oh, and I've been given a 1/4" limitation on the diameter of this job.... I actually have a sample cable where there is a single insulated center conductor wrapped in two layers of steel reinforcing strands. They used the center for one conductor and soldered/brazed to the outer steel strands for the other. (I can be > 1/4" diameter near the transducer but the cable is fed through a 1/4" hole.)

But I'm not sure that will meet the Class I Div I requirement that they are looking for (although maybe if the sensor itself is C1D1 then maybe???

I'm not actually very optimistic finding something but figured if anyone had seen something like this in the past, I'd find them here. Thanks

Norm
2000 feet and class 1 Div 1 AND only 1/4" dia uhhhh sure you cant make this more of a challenge ??

hmmm radio?? IR transmitter??

How big is sensor and what does it sense?
Are you hanging just the sensor? If sensor is attached to something on hoist cable use two independent insulated from everything and run signal thru the two hoist cables.


What you could do if you are only hanging the sensor is run a tube down the pipe and use a pump to pull out a sample. transport time thru tube would have to be calculated. This is what I did on holes drilled in garbage dump to check combustible prior to torch cutting the 8" casing - but we were only 120 feet down too.

 

[TConnolly]

A 2,000 foot long #16 copper wire will have about 54 MPa of tensile stress in it near the top of the well. The tensile strength of copper wire is about 70 MPa. So the copper should be able to support its own weight. The big question is the insulation, how much it weighs and what its tensile strength is. I don't have any info on that nor would I try and calculate it, but if you get with the wire manufacturers they may be able to provide that info.

 

[milldrone]

Hi all,

I'm looking for a cable the can work with a 4-20mA pressure transducer but that also has a high tensile strength so I can hang the transducer from the same cable down into a 2000 ft. deep well.

Oh, and I've been given a 1/4" limitation on the diameter of this job....

It's been a while since I was in the oil fields. But I remember them using something like this.
http://www.camesainc.com/catalog2004/Conductors.htm
http://www.camesainc.com/catalog2008/EMC Catalog 2008 18-20.pdf

Although the stuff they were using was around 1/2" but it was 3 miles long!

 

[ndzied1]

It's been a while since I was in the oil fields. But I remember them using something like this.
http://www.camesainc.com/catalog2004/Conductors.htm
http://www.camesainc.com/catalog2008/EMC Catalog 2008 18-20.pdf

Although the stuff they were using was around 1/2" but it was 3 miles long!

Milldrone - that is the stuff on the example I was talking about.

The transducer is a pressure sensor that gets dangled (for lack of a better work) into a natural gas well (yes, it is similar to what they do at oil wells). In the bottom of the well may be water which comes out of the ground as the gas is drawn off.

I don't believe hard pipe is an option. I believe they want it to be able to dangle.

2000 feet and class 1 Div 1 AND only 1/4" dia uhhhh sure you cant make this more of a challenge ??

Hence my lack of optimism. Actually, if the well is sour gas then there is Hydrogen Sulfide to deal with so corrosion could be an issue too

I guess if it were all easy, they wouldn't call it work...

 

[leitmotif]

Hmm sounds just like drilling in garbage dumps for methane extraction systems.

Dangle 2000 feet of 1.4 polypropylene tubing down well and put transmitter and or gage at the top. Subtract the head of gas if you want to be real accurate. Or use a pump at the top if you want. If you get water at the top pull tube until no more water (may be a challenge depending on pressure at the top).

Hmmm is 2000 foot a standard length I wonder.

Dan Bentler

 

[rpoet]

Norm,
You may very well be able to get something custom made at those lengths.

Two possible solutions come to mind:

Contact Samson Rope about having something made using Tech-12.

http://www.samsonrope.com/index.cfm?rope=200

Tech-12 is a synthetic aramid rope that has very low stretch, and high strength. It's usually made as a 12-strand hollow braid rope. Samson may be able to run a pair of insulated wires (that you'd supply) down the middle of the braid during manufacture. Teflon wire would probably be a good choice with the harsh conditions in the well. You'd have to check with Samson about the compatibility of Tech-12 with hydrogen sulfide gas, but it's a pretty tough material.


My second suggestion would be to contact VER Sales at:

2509 North Naomi St.
Burbank, Ca. 91504
800-229-0518

Ask to talk to Vince in sales.

They have the ability to do nylon and PVC overmold extrusion over cables. I'd suggest nylon (provided it's compatible with the expected environment) over a bundle of a strand of 1/16" 7x19 stainless aircraft cable and two teflon insulated wires; the aircraft cable gives you the tensile strength and the wires give you your electrical connection. The nylon would mechanically bond all three strands together mechanically and give you pretty good abrasion resistance. I know VER Sales extrudes over aircraft cable, but I'm not sure if they can cover multiple strands.

As for the C1D1 rating, I'm not too sure what to do about that; is an intrinsically safe barrier possible with a 4-20ma current loop? The cable would be custom, and I wonder if your client would want some kind of certification.

As this is as much a rigging project as a it is an electrical project, I'm happy to help. PM me if you need more help.


-rpoet

 

[BryanG]

There are some cables made for use with lifts (elevators). I was looking at using a cable to pull a machine through a pipe and needed strong and light. I can't remember where I found them but I am sure that a Google would find it again. You don't find many lifts at 2000ft (610metre), but it worth asking if it will do the job.

Bryan

 

[TimWilborne]

I'm sure you've already thought of this Norm, but I'm having trouble figuring out what you are going to do. How are you going to vent your pressure sensor?

 

[nonuke]

You can use a pressure sensor from E+H "waterpilot" or similar, that comes with the electric cable and venting tube all in one cable and is IP67

 

[TimWilborne]

You can use a pressure sensor from E+H "waterpilot" or similar, that comes with the electric cable and venting tube all in one cable and is IP67

But not 2000' long

 

[Clay B.]

I'm sure you've already thought of this Norm, but I'm having trouble figuring out what you are going to do. How are you going to vent your pressure sensor?

If you use an "absolute" pressure transducer doesn't that eleminate the need for a vent? Seems in my clouded memory someone told me that was a reason to use one.

As far as the cable, when I worked for Corning, Commscope did some pretty exotic cables. I know they created the fiber optic cable that runs the transatlantic route. While you do not need the fiber, in this same cable was copper conductors to power the phototronic repeaters.

 

[TimWilborne]

If you use an "absolute" pressure transducer doesn't that eleminate the need for a vent? Seems in my clouded memory someone told me that was a reason to use one.

Maybe, it will be a new one on me if it is. I always thought you needed a differential pressure of the sensor to measure. If you look closely at a IP67 pressure sensor you will usually see a fine piece of plastic sticking out of the back or running through the wire. This is a tube to allow the pressure sensor to reference ambient pressure for it's measurement.

I may be wrong but I'm guessing that we are trying to measure the volume of water in the well that needs to be pumped out

 

[Clay B.]

Maybe, it will be a new one on me if it is. I always thought you needed a differential pressure of the sensor to measure. If you look closely at a IP67 pressure sensor you will usually see a fine piece of plastic sticking out of the back or running through the wire. This is a tube to allow the pressure sensor to reference ambient pressure for it's measurement.

I may be wrong but I'm guessing that we are trying to measure the volume of water in the well that needs to be pumped out

I wasn't sure either so I looked it up. Here is how a absolute pressure transducer is built.

http://content.honeywell.com/sensing/prodinfo/pressure/technical/008116_1.pdf