a. There is less training and skill required.
b. It is applicable to all metal thicknesses.
c. It has a longer burn time.
d. It has the ability to cut in hard-to-reach spots without frequent electrode changing.
e. There is no electrical hazard after ignition. The electrical circuit is used only for igniting the thermic cable.
f. It cuts on the surface as well as underwater.
g. It is lightweight.
h. Only one gas (oxygen) is needed.
The disadvantages of the Kerie Cable are as follows:
a. It requires more oxygen.
| b. It will not cut concrete, rock, or non-ferrous metals.
Learning to use the Kerie Cable is very simple. To familiarize the diver and the topside support crew with the equipment and operating procedures, the team should follow the set-up described below and perform a cut on the surface. Use a piece of mild steel plate as practice material. Set the oxygen pressure to about 200 psi and turn the Hoke valve to the ON position. Close the knife switch and touch the practice metal with the tip of the Kerie Cable. The cable should ignite immediately. Lift the knife switch (switch off) when ignition takes place. Proceed to cut the metal, starting at the edge. Once in the water, the diver will quickly become accustomed to the feel, sound and use of the Kerie Cable.
2-4.2 Materials Required for Kerie Cable Cutting. The Seeler Enterprises LU 001 Exo thermic Cutting Tool (Kerie Cable) is supplied with a surface control panel. (See Figure 2-8, which includes an oxygen regulator, an on-off and vent flow valve for the oxygen and a knife switch and electronical and oxygen connections. Oxygen, batteries and ground cable are not included.)
The following equipment is required:
a. One control panel.
b. One three-cylinder, 10-foot, high pressure (HP) oxygen manifold.
c. Three full 220-cubic foot oxygen cylinders.
d. One 100-, 200- or 250-foot extension lead.
e. One insulating sleeve.
f. One 6.4mm x 6.4mm (1/4-inch x 1/4-inch) British standard pipe (BPS) double male adapter.
g. One 6.4mm x 3.2mm (1/4-inch x 1/8-inch) double male adapter.
h. A length of 6, 9 or 12mm (0.24-, 0.36- or 0.48-inch) Kerie Cable.
i. Two fresh 12-volt, 20-ampere hour batteries or a welding machine capable of supplying 400 amps/80 volts.
j. One pair of heavy duty wire cutters.
The Kerie Cable is manufactured in three sizes: 50-foot lengths of 9mm (0.36-inch) and 100-foot lengths of 12mm (0.48-inch) for cutting heavy plate wire and shackles, etc and 50-foot lengths of 6mm (0.24-inch) for cutting thinner plate, wire and shackles. The cable is the cutting electrode and is connected to the control panel via the extension lead, which supplies both power and oxygen to the cable.
The control panel is connected to three1 oxygen cylinders using the 10-foot, HP manifold and to the power supply using the extension lead. Negative (-) amperage and low pressure oxygen are supplied through the control panel (see Figure 2-9).
While oxygen is flowing through the cable, it is ignited by closing the knife switch and touching the tip to the striker plate. The striker plate is connected to the positive (+) side of the paralleled batteries or a welding machine. The oxygen flow is directed to the cable through the three-way HOKE valve on the control panel. Once ignited, the knife switch is opened to cut off the power. The Kerie Cable will continue to burn until the oxygen is cut off or completely consumed. The burning cable can be stopped by turning the HOKE valve to the OFF position, which stops the flow of oxygen. The burning cable can be stopped almost instantly by turning the HOKE valve to the VENT position. This vents the oxygen to the atmosphere, allowing water to flood the cable and extinguish the flame. This should only done in an emergency situation as flooding with water causes difficulties when attempting to relight the cable underwater.
2-4.3 Equipment Set-up. The following procedure should be followed when setting up the Kerie Cable equipment:
It is very important that ignition not occur with oxygen pressure too low. To do so will cause the cable to burn inside itself and as full pressure is applied, the flame will burn out sideways along the length of the cable in a series of blow holes that can cause diver injury.
a. Connect three full oxygen cylinders together with the 10-foot, HP manifold. Check the HP gauge for cylinder pressure.
b. Turn the valve marked ON/OFF/VENT to the OFF position.
c. Turn the regulator OFF.
d. Connect the HP manifold to the fitting marked HP OXYGEN IN on the control panel.
1. Blanking plugs are supplied with the high pressure manifold for use on small cutting jobs, when only one oxygen cylinder is required.
e. Connect a length of 100-, 200- or 250-foot extension lead to the control panel fitting marked LP CUTTING OXYGEN OUT.
f. Open the knife switch.
g. Connect a length of 100-, 200- or 250-foot electric lead to the control panel fitting marked NEG AMPS OUT.
h. Place two fresh, 12-volt batteries of at least 20 ampere hours on a non-conductive surface (wooden plate, rubber mat etc). Connect the batteries in series.
i. Connect the negative side of the batteries to the fitting marked NEG. AMPS IN on the control panel.
j. Connect the positive side of the batteries to a suitable length of wire with the opposite end connected to the striker plate (ground).
2-4.4 Kerie Cable Preparation. Kerie Cable comes from the manufacturer in individual coils that are tightly wound and should be opened and inspected for cuts in the plastic coating. The following procedure should then be followed:
a. Recoil the Kerie Cable in large loops to prevent kinking.
b. Connect the cable to the extension leads with the appropriate reducer.
c. Blow down the hose with oxygen for approximately 20 seconds.
d. Slide the red plastic insulating sleeve along the Kerie Cable until the joint between the cable and the extension lead is completely covered.
e. The equipment is now ready for cutting.
2-4.5 Cutting Underwater. After the striker plate is secured at the work site, the cable should be pressurized and passed to the diver. The cable is taken down with sufficient oxygen flow to exclude water from entering the bore. The gas pressure need only be increased to overcome hydrostatic pressure.
Upon reaching the work site, the diver, when ready, should call and wait for gas pressure to be increased. A delay of approximately 20 seconds is necessary between applying full cutting-gas pressure and closing the knife switch to allow time for the oxygen pressure to build up along the full length of the cable. The following procedure should be followed:
a. The tender will increase the oxygen supply to the proper over bottom pressure. (See Table 2-6 for proper over bottom pressure formulas.)
b. The diver calls for SWITCH ON when an increase in the amount of bubbles is observed emerging from the cable.
c. The tender (phone talker) closes the knife switch and then responds with SWITCH ON.
d. The diver should then touch the tip of the cable to the striker plate. The ammeter will give a reading as the diver attempts ignition and then will fall back to zero when ignition is achieved.
e. Once it is obvious that ignition has been successful, the diver announces, "I have ignition."
f. The tender (phone talker) will then open the knife switch, isolating the electric circuit.
Typically, the Kerie Cable burns at about two feet per minute. The selection of cable size depends on the thickness of the metal being cut (see Table 2-7). Table 2-8 lists typical oxygen/cable consumption ratio.
2-4.6 Cutting Technique. To begin cutting, touch the ignited tip of the Kerie Cable to the material to be cut. The material will instantly begin to oxidize and burn away. Hold the cutting cable at about 90o perpendicular to the work, keeping the tip in constant contact with the material being cut. Keep the tip moving into the cut and keep hands at least six inches from the flame .
2-4.7 Cutting Thin Metals. When cutting thin steel plate, wire rope or routine light work, the 6mm or 9mm (0.24-inch or 0.36-inch) Kerie Cable should be used. Use a brushing motion and several passes to eliminate molten metal from the cut.
2-4.8 Cutting Thick Metals. When cutting thicker metal (2-1/2 inches and greater), use the 12mm (1/2-inch) cable and a brushing motion to allow the metal surrounding the cut to cool enough to prevent molten metal.
Thick steel, such as propeller shafting, should be cut from the outside, working around the circumference, withdrawing the Kerie Cable every few seconds to allow water to enter the cut. A brushing or stroking action in the direction of the intended cut should be used.
6mm (0.24 in.)
D + (250 to 300 psi)
9mm (0.36 in.)
D + (300 to 340 psi)
12mm (0.48 in.)
D + (340 to 380 psi)
1. A 40 to 50 psi range is allowed for diver preference.
1. A 40 to 50 psi range is allowed for diver preference.
Where D = depth in feet of sea water
Example: At a depth of 60 FSW using 6mm cable, overbottom pressure is: 60 + 275 = 335 psi.
Was this article helpful?