Method of protecting a cable splice with a splice closure having pressure measuring means

DESCRIPTION

The present invention relates to a closure device for protecting a substrate, such as a splice in multi-conductor electric cables, in particular communication cables, against the penetration of water into the joint.

Following is described in, for example, US Patent No. 4,466,843 in the name of Shimirak, several methods have been proposed to protect the joint against water penetration. Typically, these methods may consist of filling a reservoir that surrounds the joint, with a hardenable liquid sealing agent. In the Shimirak patent, the supplementary operation is performed which consists of compressing the reservoir while the liquid sealing agent was in the liquid state, and keeping it under compression for a sufficient time so that the liquid sealing agent can harden.

As described further in the Shimirak patent, it is convenient to compress the reservoir until a predetermined pressure level is obtained, generally of the order of approximately 0.21 to 0.84 kg / cm.², 3 to 12 pounds / inch² and preferably on the order of approximately 0.56 to 1.75 kg / cm² (8 to 25 pounds / inch²). Naturally, it would be convenient to know when this predetermined pressure level is reached. A method to determine this predetermined pressure level is to introduce a transducer into the tank. The pressure that reigns in the tank can be determined simply by monitoring the transducer. This method is satisfactory, but it has the disadvantage that the transducers are expensive and that several electronic devices are needed to electrically monitor the transducer.

Therefore, a relatively simple and low cost procedure is needed to monitor the pressure inside the tank.

In one aspect, the present invention provides a closure device for the protection of a substrate that includes:

a deposit located around the substrate;

a hardened liquid sealing agent inside the tank;

a pressure measuring tube that communicates between the inside and outside of the tank, the end of the tube located outside the reservoir being tightly closed, and containing the hardened sealing agent tube that has been driven into the tube by the pressure applied to the closing device before hardening.

The present closing device has the advantage that the pressure measuring tube provides a relatively simple and low cost means of measuring the pressure in the tank.

According to another aspect, the invention provides a method for protecting a substrate, which consists of:

placing a tank around the substrate with a pressure indication tube in communication between the inside and outside of the tank, the tube being hermetically closed at the end located outside the tank;

introducing a hardenable sealing agent into the tank;

increase the pressure inside the tank, this pressure increase being sufficient to drive the sealing agent to a predetermined distance along the tube; and harden the sealing agent.

In another aspect, the present invention provides a set of elements to protect a substrate, which includes:

a deposit intended to be located around the substrate;

a hardenable sealing agent intended to be introduced into the tank;

a means of applying pressure to the sealing agent contained inside the tank; and a tube for measuring the pressure applied to the sealing agent inside the tank.

In the following, some embodiments of the invention were described, by way of example, referring to the attached drawings, in which:

Figure 1

It is an open side view of a closure device according to the invention.

Figures 2 to 5

They are side views of a closing device according to the invention.

Figure 6

It is a side view of a closure device that has a plurality of pressure measuring tubes.

Figure 7

It is a side view of another embodiment of a pressure measuring tube according to the invention.

Referring more in detail to the figures, a closing device 10 is shown in Figure 1 that protects a joint between two cables. Each of the cables 14, 16 has a plurality of individual insulated conductors 18, 20, respectively. The conductors 18, 20 are connected by modular connectors

22 To form the closing device, first, a sealing tape 24 is wound around each of the cables. It is preferable that this sealing tape 24 is the S1061 tape (or equivalent) that can be obtained from the Raychem Corporation. This sealing tape is preferred since it provides a good hermetic seal based on its convenient chewing properties. On a limb

005 348 of the closure device 10, a hollow pressure measuring tube 28 is placed on the sealing tape 24. Preferably, another layer of sealing tape 31 is then wound around the pressure measuring tube 28 and the cable 26. Due to the convenient properties of the sealing tape 24, 31, the pressure measuring tube 21 is embedded inside the sealing tape 24, 31 and consequently a complete hermetic seal is obtained around the measuring tube of pressure

28. Next, a flexible tank 30 was placed around the junction 12. At the end of the closure 12 where the pressure measuring tube 28 was located, the flexible tank 30 is placed on the sealing tape 31 and the pressure measuring tube 28. On the other end of the closure 12, the flexible tank 30 was simply placed on the sealing tape 24. Next, a coating 32 of vinyl tape is formed on the flexible tank 30 and the cables 14, 16. At this point in the operation, a complete seal is obtained with the flexible tank 30 and the pressure measuring tube 28, and therefore, when the hardenable liquid sealing agent 34 is introduced into the reservoir 30, the liquid sealing agent 34 cannot escape along the cables 14,

16. After the introduction of the liquid sealing agent 34, the open central part of the tank can be folded on itself and closed.

Since it is necessary to apply a considerable compression force to the pressure measuring tube 28, it is necessary that the pressure measuring tube is made of a relatively stiff material that does not crush under the compressive force and does not widen when its pressure Internal increases. Although numerous materials are suitable for this application, as those skilled in the art will observe, a particularly preferred material for the pressure monitoring tube in nylon 6. Other preferred materials are nylon 11 and nylon 12, although they are not as convenient. like nylon 6, since they are more expensive. Polyethylene may also be used, but this material is not preferred since it is not as chemically compatible with the liquid sealing agent as nylon-type materials.

The hardenable liquid sealing agent 34 that has been introduced into the tank, as illustrated in Figure 2, was not yet subjected to pressure. In this case, the pressure measuring tube that communicates between the inside and outside of the reservoir 30 was substantially devoid of hardenable liquid sealing agent 34.

In Figure 2, it is seen that a compression coating made of tape 36 has been applied to the closing device 10. This compression coating made of tape 36 is constituted by a plurality of layers of tape that serve to increase the pressure in the inside the tank 30. The preferred tape is a plasticized vinyl tape, such as the PERMAWRAP tape (which can be obtained from Teltronics, Austin Texas). Although this tape coating is the preferred means for increasing the pressure inside the reservoir 30, it would be possible to use to increase the pressure inside the tank 30, other means such as air chambers. The compression coating made of tape 36 causes the hardenable liquid sealing agent 34 to move along the pressure measuring tube. Although the application of a reduced number (usually 4) of tape layers increases the pressure inside the tank 30, it is necessary to apply at least one layer of supplementary tape to increase the pressure inside the tank to the predetermined level I want it to be measured by indicator means located in the pressure measuring tube. The total number of tape compression layers would usually be approximately 5, although it may be higher or lower, following the predetermined pressure level that one wishes to obtain. As can be seen in Figure 2, the pressure inside the reservoir 30 has reached the desired predetermined level marked by the indicating means 38 in the pressure measuring tube

28.

When the predetermined pressure level in the reservoir 30 has been reached, it is convenient to hermetically close and remove the pressure measuring tube 28 so that it is possible to terminate the circulating device 10. For this purpose, the pressure measuring tube 28 it can be folded over the closing device as shown in figure 3, in the direction of arrow 40. When the pressure measurement tube 28 was folded, the tube bends (and therefore closes tightly, and therefore, the liquid sealing agent 34 cannot escape from the pressure measurement tube 28. It is evident that the Pressure measuring tube 28 should preferably be sufficiently flexible to create a pressure-tight seal. On account of the hermetic seal of the pressure measuring tube 28, the sealing agent 34 remained at its predetermined level in the pressure measuring tube 28, whatever the internal pressure of the reservoir 30. The hardening of the liquid sealing agent 34 , allows the sealing agent 34 to permanently maintain its predetermined level, even if the pressure measuring tube 28 is further perforated or opened. This has an important advantage that in case of failure of the closing device 10, the operator does not have to observe the bent pressure measuring tube 28 to determine if during the installation the correct pressure in the tank has actually been reached 30

It is particularly convenient that the reservoir 30 is kept under pressure for a sufficient period of time to allow hardening of the liquid sealing agent

3. 4. Although this did not have any effect on the sealing agent 34 contained in the pressure measuring tube 28, since the latter has already been crushed to separate it from the main source of sealing agent, however, this is necessary to maintain the pressure in order to guarantee sufficient splicing of the joint.

In Figure 4, it was observed that a layer of

005 348 supplementary tape 42 is applied on the pressure measuring tube 29 to hold the pressure measuring tube 28 to hold the pressure measuring tube in the tank 30 and in the closing device 10.

Finally, a closure closure 44 was placed around the reservoir 30 and the pressure measuring tube 28, as shown in Figure 5. The closure body may be constituted by any commercially available or well-known closure body. Follow is shown in Figure 5, the preferred closure body, is a heat-recoverable body 46 of the type of envelope whose sealing is ensured by a closure 48 of the U-shaped rail and channel type.

The pressure measuring tube 28 can take any one of several forms. In a particular embodiment shown in Figures 1 to 3, one end 50 of the pressure measuring tube outside the tank 30 was hermetically closed. As can be seen, for example in Figure 1, the limb 50 of the measuring tube 28 was hermetically closed, while the other limb 52 was open to the pressure of the reservoir 30. Therefore, the pressure from the reservoir 30 can be transmitted to the pressure measuring tube 28 to directly indicate the pressure that reigns in the reservoir 30. Although the pressure in the pressure measuring tube may not be linearly related to the pressure in the tank. inside the tank, for example, because of the presence of air inside the tube, however, the pressure can be calculated using well-known scientific principles. It is preferable that the pressure measuring tube 28 is provided with means to indicate the pressure inside the reservoir 30. These indicating means can have numerous shapes, as could be observed by those skilled in the art. Following is shown in Figures 1 to 3, the indicating means may be marks 38 placed on the same pressure measuring tube 28.

In the following, reference is made to Figure 6, which represents four different pressure measuring tubes 28A, 28B, 28C and 28D. A limb 50 of each of the pressure measuring tubes 28A to 28D, that is the limb outside the reservoir 30, was hermetically closed. As noted, the marks 38 located on the pressure measurement tubes 28A to 28D progressively approach the hermetically sealed end 50 of each of the pressure measurement tubes. Marks 38 represent a certain predetermined pressure level. As the marks 38 approach the hermetically closed end of the tubes, the predetermined pressure level increases correspondingly. For example, the lowest predetermined pressure level of the pressure measuring tubes shown in Figure 6 corresponds to tube 28A. This pressure measuring tube 28A was generally used for the most important closure devices. It was assumed that the marks 38 formed in the pressure measuring tube 28 correspond to a pressure of approximately 0.56 Kgg / cm² (8 pounds / inch²). On the other hand, the highest predetermined pressure level was produced with respect to the tube 28D which was generally used for the smaller closing devices. It was assumed that the marks 38 formed on the pressure measuring tube 28D correspond to a pressure of approximately 1.75 kg / cm² (25 pounds / inch²). The other pressure monitoring tubes 28B and 28C correspond in Figure 6, at predetermined pressure levels between approximately 0.56 and 1.75 kg / cm²(8 and 25 liters / inches²). Naturally, the predetermined pressure level was predetermined according to the size of the closing device and the desired pressure level. therefore, the indication that the pressure measuring tubes shown in Figure 6 are particularly adapted for pressures between 0.56 and 1.75 kg / cm² (8 and 25 pounds / inches²) has a merely illustrative character and no limiting character.

Marks 38 of Figures 1 to 6 may be represented by a group of two parallel lines or by a color band to provide a small range of predetermined pressure levels for each pressure measurement tube. In a variant, the marks 38 may be represented by graduations in the pressure measuring tube. Those skilled in the art could imagine another variant of brands.

Figure 7 shows another embodiment of the pressure measuring tube. This pressure measuring tube 54 consists of a piece of hollow tubular material 56 with a pressure gauge 58 on one end 60. The pressure gauge 58 is located at the end of the pressure measuring tube 54 located outside the reservoir 30 In this case, too, the open end 62 of the tube 54 is in contact with the inside of the tank 30. Therefore, when a compression tape coating is applied to the closure device 10, the pressure inside the reservoir 30 would be indicated directly by the pressure gauge 58. Therefore, the use of the pressure measuring tube 54 would be identical to that of the pressure measuring tubes 28 described above, since upon reaching the desired level of the pressure, the tube 54 will be folded as shown in the Figure 3, to keep a permanent record of the level of pressure actually reached during installation. After the pressure measuring tube 54 had been bent, the pressure gauge 58 was removed and the tip 60 of the tube 54 was hermetically sealed. The hardening of the liquid sealing agent could occur before or after removing the pressure gauge.

An additional requirement applicable to the material of the pressure measuring tube is that it should be transparent or translucent, so that it is possible to observe the hardenable liquid sealing agent and compare it with the indicators (if present). The dimensions of the tube are particularly important. The inner diameter of the tube was limited by the viscosity and surface tension of the encapsulation material. For example, if the inner diometer is excessive,

005 348 the encapsulation material flows simply, whatever the pressure inside the reservoir. Therefore, the inner tube diameter was preferably between 3,175 and 6, 35 mm (1/8 and 1/4 inch).

The length of the pressure measuring tube depends more on practical motifs. If the tube is too short, the indicators are hidden inside the closing device, while if the tube is excessively long, the tube bothers during the assembly of the closing device. Accordingly, the preferred length of the pressure measuring tube was generally between 25.4 and 50.8 cm (10 and 20 inches).

The shape, dimensions and materials may be variable and, in general, whatever accessory or secondary, provided that it does not alter, change or modify the essentiality of the object described.

The terms in which this Report is written are true and a true reflection of the object described, taking shots with a wide caraócter and never in a limited way.

The applicant reserves the right to obtain the appropriate Supplementary Additions for the improvements or improvements that may be advised in the future.

005 348