1. Field of the Invention
This invention relates generally to the field of cable terminations and more particularly to a waterproof termination assembly. This invention relates more particularly to a field serviceable termination assembly subject to extremely high tensile stress. This invention relates even more particularly to a termination assembly having an improved water-blocking system.
2. Discussion of the Related Art
In towing electrical equipment beneath the water surface, invasion of water into the electrical circuitry is often of concern. This is particularly true after a repair has been made to an otherwise water-tight circuit. This invention is a method and apparatus for making a water-tight connection of electrical transmission lines and for providing easy access to repair such connections if necessary.
In the field of marine seismic exploration, an acoustic signal is generated in the water by a source. Traditionally the acoustic signal was generated by explosives, but due to environmental concerns and safety, other sources such as air guns are used. The advantage of using air guns is the ability to adjust the signature of the acoustic source by changing the volume of air explosively released into the surrounding water.
To actuate an air gun, a chamber is pressurized with a volume of air to a desired pressure. A solenoid in the air gun reduces the pressure in a counteracting chamber which allows the pressurized air to open a valve and escape into the water to create the acoustic pulse. The solenoid is electrically actuated and is coupled to a control device aboard the vessel through the cable.
It is common that more than one air gun is used forming an air gun array with as many as sixteen air guns employed in a single array. If one gun in the array fails, the acoustic signature also changes. This requires that the gun array or "string" be brought aboard the vessel to replace the malfunctioning air gun. This increases time to conduct the survey which is directly correlates to increased costs.
One of the primary factors contributing to downtime is the invasion of water into the electrical connections in the cable. Because of the nature of the cable construction and cable insulators, water may "wick" along the conductor or transmission line and reach an electrical connection, causing corrosion and shorting of the connection. Water often invades as a result of a breach in the cable skin. At other times, water gains entry through other connectors in the line. As a result, it is not unusual that the cable head connections between the cable and the submersible device (air gun array) to be replaced at periodic intervals. This again results in increased costs due to the down time needed to make the replacement.
There has been a long felt, yet unsolved need for a termination assembly for making submersible electrical connections which prevents water from reaching electrical connections. Similarly, there has been such a need for a termination assembly which allows for repairs in the field, yet maintains its water-tight integrity after such repair. It is a purpose of the above invention to provide such a termination assembly which satisfies such a need. It is a further purpose of this invention to provide a termination assembly which blocks the migration of fluids along each conductor.