The present invention relates to a method and device for sealing the entrance of an elongated element (1) into the lower end of an offshore tube (8), --including the steps of arranging a plug-like device (2) on the element, --pulling a predetermined length of the element into the tube, --and fixing the plug on the element surface at the bellmouth entrance (7) of the tube, the outer diameter of the plug being somewhat smaller than the inner diameter of the tube. Expandable foam is injected to a space (11,12) between the outer surface of the plug (2) and the inner surface of the tube (8), --in order to substantially fill said space. The foam is supplied to the space (11,12) from at least one foam container (15) placed inside the plug, --via ducts (13,14) within the plug. The foam container (15) is operated from a drive gas cartridge (16) also arranged within the plug (2) and is operable by an ROV.

BACKGROUND OF THE INVENTION 
1. Technical Field 
The present invention relates to a sealing device or plug for sealing off a 
elongated element, such as an cable, a pipe or an umbilical, at its 
entrance into an apparatus, in particular at the lower horizontal end of 
an offshore J-tube, leading from the sea bed up to a platform structure. 
The sea bed may be several hundred meters below the sea level. 
2. Description of the Prior Art 
In some cases it is desirable, after a elongated element has been installed 
within an J-tube, that the sea water surrounding the element within the 
J-tube is deoxidized to prevent or reduce corrosion of the element and of 
the inner walls of the tube. In order to neutralize the sea water in the 
tube, inhibiting agents are added to the water, and the inside pressure is 
normally some 5-6 bar more than the pressure of the surrounding water. A 
problem arises, however, due to difficulties in obtaining a full seal 
between the surface of the elongated element and the tube entrance. If the 
seal is poor,--the external sea water will be gradually exchanged with the 
inhibited sea water within the tube. A suitable sealing device should also 
prevent pollution that might be caused by leaking inhibiting agents into 
the sea. 
From GB 2 188 999 B, there is known a sealing device or plug comprising at 
least two elements which are arranged to be pressed against each other, 
against a circumference of the elongated element and against the aperture 
of said apparatus. At least one of the elements is hinged to the apparatus 
In GB 2 281 365 A, a sealing device or plug comprises centralizing means 
arranged around the elongated element inside a pull-in-flange at the lower 
entrance of the J-tube, sealing means arranged around the elongated 
element next to the centralizing means, and formed as a one-piece split 
annulus, the split being in a plane substantially parallel to the axis of 
the annulus and to the axis of the elongated element, and pressure means 
for pressing the sealing means to sealing contact against the elongated 
element, against the flange surface and against the centralizing means 
In GB 2 297 59 A, a sealing device or plug consists of two substantially 
identical parts or halves which are hinged together along an axis 
substantially parallel to the axis of the elongated element, each half 
comprising a centralizer part, a sealing part and tensioning parts capable 
of pressing the sealing means to sealing contact against the elongated 
element, against the inner surface of the J-tube and against the 
centralizing means. There are described means for interlocking the two 
halves with each other and interlock the device with a bellmouth flange. 
There are also described separate interlockable two-part means for 
exerting a certain friction against the surface of the elongated element 
when the sealing parts are interlocked but not yet tensioned. 
The technical problem is--as mentioned--to provide a reliable seal at the 
subsea entrance of an elongated element into a socalled J-tube bellmouth. 
The prior art solutions all rely on compression of rubber gaskets to 
obtain a suitable seal, but when the inside of the J-tube is rough it is 
difficult to obtain a good seal. 
SUMMARY OF THE INVENTION 
The main object of the present invention is to provide an alternative 
efficient full seal at the subsea entrance of a J-tube, --even if the 
inner surface of the tube is rough. The basic idea is to provide sealing 
by injecting an expanding foam into space provided between a sealing 
device and the J-tube. 
It is well known from prior art such as U.S. Pat. No. 4,332,975 to provide 
a sealed cable closure by filling a cavity with an expandable foam like 
polyurethane resin. With the present invention, however, there is obtained 
an efficient sealing device which may be installed operated at subsea 
installations by an ROV. 
Above mentioned and other features and objects of the present invention 
will clearly appear from the following detailed description of embodiments 
of the invention taken in conjunction with the drawings.

DETAILED DESCRIPTION OF THE INVENTION 
In FIGS. 1 and 2 are shown an elongated element 1 and a sealing device 2 or 
plug installed on the element. The sealing device consists of two parts 3 
and 4. The parts 3 and 4 may be interconnected with a number of bolt 
arrangements 5 and 6. This sealing device 2 may be arranged to be 
interlocked with a bellmouth flange 7 of a J-tube 8 and there may be 
provided a friction device (not shown) for facilitating adjustment of the 
sealing device along the elongated element before initiating the sealing 
process. 
The installation of the elongated element and of the sealing device can be 
performed as follows: 
Before the elongated element 1 is lowered to the sea bed for insertion and 
pulling into the J-tube 8, the sealing device 2 is installed on the 
elongated element. The dimensions can be chosen such that the 
interconnected parts 3 and 4 may slide freely on the surface of the 
elongated element 1 and freely within the J-tube 8, whereas a friction 
element can prevent uncontrolled axial movements of the sealing device on 
the surface of the elongated element. 
The elongated element 1 with the sealing device 2 is now carefully lowered 
from the cable ship to the subsea entrance of the J-tube 8. The end of the 
elongated element is pulled into and up through the J-tube to a topside 
termination and installation (not shown). The sealing device 2 is 
installed within the J-tube 8 at any time during installation of the 
elongated element within the J-tube, and catching means (not shown) may 
catch the J-tube flange 7. As soon as the desired position of the 
elongated element within the J-tube and sealing device is obtained, the 
sealing process of the present invention may be initiated. 
The device or plug 2 may be provided with rubber seals 9 and 10 in order to 
define a compartment 11 between the plug surface and the J-tube surface. 
The concentrical plug 2 may be provided with at least one circumferential 
groove 12 provided in its outer surface between the rubber seals 9 and 10. 
The plug parts may be made of nylon or other convenient material. Internal 
ducts 13 and 14 are leading to the groove 12 and the compartment 11 from 
at least one foam cartridge 15 which is fitted into a cavity in one or 
both halves. The foam cartriges may be of the two component type. The foam 
cartriges may be interconnected with a cartrige 16 containing CO.sub.2 or 
similar agents for expulsion of the foam. The cartridge may be triggered 
by an ROV operating a handle 17. The foam produced by the foam cartridge 
15 will then be led via the ducts 13 and 14 in the plug 2 to seal the 
space 11 between the plug 2 and the J-tube wall 8. The pressure exerted by 
the gas and foam must be high enough to overcome and press out the water 
contained in the compartment 11 to begin with. Ducts (not shown) leading 
from the compartment 11 to a membrane 18 at the salt water side of the 
plug may be provided to show that the release has worked properly. 
A good seal--preventing leakage of corrosion inhibiting fluids from the 
J-tube,--also when the inside walls of the tube is rough,--is thereby 
obtained. This sealing method and means for sealing may be provided as 
indicated above as a standalone sealing process or it can be provided in 
addition to sealing means described in our mentioned GB 2 188 999, GB 2 
281 365 and GB 2 297 593. 
The above detailed description of embodiments of this invention must be 
taken as examples only and should not be considered as limitations on the 
scope of protection.