TOP DRIVE SERVICE LOOP CABLE ASSEMBLY WITH HEATING ELEMENTS

Abstract

A cable including at least one primary conductor and at least one secondary conductor. A metallic shield element surrounds the primary and secondary conductors. A jacket surrounds the elements of the cable. At least one heating element is disposed under the shield element.

Claims

1. A cable comprising: at least one primary conductor; at least one secondary conductor; a metallic shield element surrounding the primary and secondary conductors; a jacket surrounding the elements of the cable; and at least one heating element disposed under said shield element.

2. The cable as claimed in claim 1, wherein said cable has an aramid fiber reinforcement layer disposed over said shield element.

3. The cable as claimed in claim 1, wherein said cable has an inner insulated jacket disposed over said aramid fiber reinforcement layer.

4. The cable as claimed in claim 1, wherein said cable has a braided armor disposed over said inner insulated jacket disposed.

5. The cable as claimed in claim 1, wherein said jacket surrounding the elements of the cable is an outer jacket disposed over said armor.

6. The cable as claimed in claim 1, wherein said cable has three primary power conductors.

7. The cable as claimed in claim 6, wherein said cable has three secondary power conductors.

8. The cable as claimed in claim 7, wherein said cable has a plurality of heating elements, disposed in interstices between said primary and secondary power conductors and directly contacting said shield element has three secondary power conductors.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0005] The present invention can be best understood through the following description and accompanying drawings, wherein:

[0006] The sole FIGURE illustrates a typical top drive service loop cable employing heating elements according to one embodiment.

DETAILED DESCRIPTION

[0007] The present arrangement as shown in the sole FIGURE, a top drive service loop cable 10 is provided with embedded heating elements 100.

[0008] The basic arrangement of top drive service loop cable 10 includes primary conductors 12, secondary conductors 14, an optional VFD (Variable Frequency Drive) shield 16, aramid fiber reinforcement 18, inner insulated jacket 20, braided armor 22 and outer jacket 24. This basic construction shown in the sole FIGURES is considered exemplary. Other constructions for heated top drive service loop cables are within the contemplation of the present invention. However, for illustration purposes the example shown in the sole FIGURE will be used to illustrate the salient features.

[0009] Primary conductors 12 are typically current carrying power conductors, used for example to power the top drive motors. Secondary conductors 14 are typically used for equipment grounding or can be used for control circuits. Optional VFD (Variable Frequency Drive) shield 16 is typically made from a copper braid or tape (sometimes a metal laminate) and is used to contain electromagnetic interference. Aramid fiber reinforcement 18 is typically used to add longitudinal strength to the cable jacket as well as to provide radial cut-through resistance.

[0010] Inner insulated jacket 20 is typically made from a thermoset rubber polymer such as CPE (Chlorinated Polyethylene). This inner insulated jacket provides protection for the inner components of cable 10 and also provides a cushion for shield 16 to prevent it from damaging the insulation of conductors 12 and 14.

[0011] Braided armor 22 is typically composed of stainless steel wires and is used to provide longitudinal strength and radial cut through resistance. Finally, outer jacket 24 is typically made from a thermoset rubber polymer, and is designed to protect braided armor 22.

[0012] In one embodiment, heating elements 100 are powered heating cables, for example as available from Thermon under such trade names as HPT, HTSX, VSX, and FP, Heating elements are independent powered electric heating elements made from a heating/electric conductor within an insulation and may include other components for strength, safety etc. . . . . Preferably, heating element 100 includes a braided or composite conductor/heating element to assist with maintaining flexibility under the ordinarily harsh environmental and use conditions of top drive service loops. The sizing and wattage of such heating elements 100 can be adjusted accordingly based on the size of cable 10, the size of the components and the composition of the polymer/insulations that require the pre-heating.

[0013] As shown in the sole FIGURE, heating elements 100 are disposed in the interstices between primary conductors 12 and the secondary conductors 14 and directly below and abutting the VFD (Variable Frequency Drive) shield 16. Contact with the metallic VFD shield 16 helps evenly and quickly distribute heat from the heating elements into the other components of cable 10.

[0014] While only certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes or equivalents will now occur to those skilled in the art. It is therefore, to be understood that this application is intended to cover all such modifications and changes that fall within the true spirit of the invention.