FORM 2
THE PATENT ACT 1970 (39 Of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION See Section 10, and rule 13)
1. TITLE OF INVENTION
A CONDUIT USED FOR LAYING OF THE OPTICAL FIBER CABLE ;
2. APPLICANT(S)
a) Name : KRITI INDUSTRIES (INDIA) LIMITED
b) Nationality : INDIAN Company
c) Address : MEHTA CHAMBERS
34, SIYAGANJ
INDORE
MADHYA PRADESH
3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed : -

A conduit used for laying of the optical fiber cable Field of Invention:
The present invention relates to a conduit which is used for laying of the communication cables. More particularly it relates to a conduit which is used for laying of the optical fiber cable.
Prior Art:
In the communications industry, the advent of fiber optic cable has had a tremendous impact due to its significantly higher data carrying capacity, particularly due to the explosion of the internet. In telecommunications service (phone, data transmission), fiber optic cable is used, along with traditional copper cable. In cable television service (CATV), fiber optic is also growing rapidly in addition to (or replacing) coaxial cable. This progression toward fiber optic cable has made the need for protection more critical, since these materials are highly sensitive to moisture and mechanical stress. Damage can be very expensive in terms of interrupted service and replacement costs. Also, these cables are installed in very long, continuous runs which require a clear, protected pathway, as well as a leak free system for air-assisted (blown in) installations. For this purpose conduits are used. The general purpose of conduit is to provide a clear, protected pathway for a cable. Advances in cable technologies, as well as the expense of repairing sensitive cable materials like fiber optic cable, have driven preferences for protective conduit over that of direct burial. Conduits provide mechanical protection to fragile cable materials like fiber optic and coaxial cables as well as protection from moisture or chemicals and even,
in some cases, animals. Furthermore, the permanent pathway provided by conduit also facilitates replacement projects or future installations of additional cable.
Buried conduit evolved from terracotta tile, cast concrete and transit to plastics in the 1960s. Originally PVC was used. But these conduits found to be failed against the
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mechanical stress, moisture and other environmental conditions. The conduit presently available is available in tubular structure. This conduit consists of two layers of the polymeric materials. The inner layer has a smooth continuous surface.
Optical fiber cable is inserted into the conduit by means of two processes namely, blowing and pulling process being the preferred one. In the blowing process, the optical fiber cable is introduced at one end of the conduit and is propelled along the conduit with the help of compressed air, the operating pressure being 16 Kgs/cm2. Installation speed of up to 30 minutes/Kilometers is achieved in the presently available conduit. The length of the optical fiber cable thus installed is limited to 1 kilometer per operation. Since the cable travels along the surface of the inner layer. Some times the inner layer gets damaged, thus preventing multiple installations.
Hence there is a need to provide a new conduit which will obviates all the problems associated with the prior art conduit.
Objects of the Invention:
The object of the present invention is to provide a conduit for laying of the optical fiber cable which overcomes all the problems associated with prior art conduits.
Another object of the invention is to provide a conduit which provides a clear and protected pathway for an optical fiber cable.
Further object of the invention is to provide a conduit which protects the cable from the mechanical stress and all environmental conditions.
Another object of the invention is to provide a conduit which provides flexibility during the installation.
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Another object of the invention is to provide a conduit which is suitable for all methods of cable installation including trenching, direct plow and installation into existing main pathways like conduit pulling, sliplining and pipe bursting.
Another object of the invention is to provide a conduit in which cable can consistently be pulled or blown in great distances and at fast rates. Yet another object of the invention is to provide a conduit which provides minimum friction in the cable installation.
Summary of the Invention:
For achieving above objects there is provided a conduit used for laying of optical fiber cable comprises:
a hollow tubular body for receiving an optical fiber through it during laying operation, said tubular body consists of outer surface and inner surface, said outer surface is made up of high density poly-ethylene material and said inner surface is made up of a polymer compound containing resin;
wherein said inner surface consists of a plurality of ribs along the periphery, said ribs are of spiral shape so that when optical fiber cable travels through said inner surface of said conduit the ribs reduces the frictional contact between optical fiber cable & conduit and provides cushioning effect to the cable for speedier installation.
According to another embodiment of the invention tubular body of the conduit has outer diameter of 40mm and inner diameter of 34mm. The thickness of silicon layer is about 0.02 to 0.07mm. Also the pitch of spiral rib is 3.45mm.
According to another embodiment of the invention inner surface of the conduit consists of 28 ribs along its periphery.
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Brief Description of the Drawings:
Figure 1 Shows the sectional view of the conduit of the prior art.
Figure 2 : Shows the perspective view of conduit according to present
invention.
Figure 3 : Shows the sectional view of the conduit according to present
invention.
Figure 4 : Shows the enlarged view of the squared portion shown in figure 3.
Detailed Description of the Invention:
The above, and the other objects, features & advantages of invention will become apparent from following description read in conjunction with the accompanying drawings.
Referring to figure 1 shows sectional view of the conduit (1) of the prior art. It consists of the outer surface (2) and inner surface (3). The inner surface (3) has a smooth continuous surface. Due to this type of construction some times inner surface get damaged when optical fiber cable is inserted in it. Also this kind of construction restricts the installation speed and the length of cable to be installed. The prior art conduit provides installation speeds of up to 30 minutes/ Kilometer and the length of the optical fiber cable thus installed is limited to 1 Kilometer per operation.
Now we will see the conduit of the present invention and how it obviates the deficiencies of the prior art conduit with reference to figures 2 to 4. Now referring to figure 2 to 4 shows the conduit of the present invention. As shown in figures 2 to 4, the conduit (11) of the present invention consists of a hollow tubular body (12). The tubular body (12) consists of outer surface (13) and inner surface (14). The outer surface (13) is made up of the High Density Polyethylene (HDTP) material and the inner surface is made up of polymer compound containing silicon. Tubular body
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(12) of the conduit has outer diameter of 40mm and inner diameter of 34mm. The thickness of silicon layer is about 0.02 to 0.07mm.
The High Density Polyethylene material delivers significant physical property advantages over other conduit materials:
a. Ductility: tough, HDPE conduit better resist brittleness with age or cold
weather.
b. Low Temperature impact resistance: The HDPE withstands low temperature
impact better than any other material. This is illustracted by impact testing on
HDPE conduit conditioned at 4°F as compared to other materials conditioned
at 73°F.
c. Permanent flexibility: HDPE conduit bends and flexes without breakage,
even with ground heaves or shifts, over a wide range of temperatures.
d. Temperature Versatility: HDPE conduit can be installed over an ambient
temperature range of -30°F to 180°F. Power conductors rated at 90°C and
medium voltage cable rated at 105°C is permitted for use with HDPE conduit.
Further feature of the conduit of the present invention is that inner surface (14) of the conduit (11) consist of plurality of ribs (15) along its periphery. These ribs (15) are of spiral shape. The pitch of spiral rib is 3.45mm. The spiral design of the ribs (15) on the inner surface reduces the frictional contact between optical fiber cable (16) and the conduit (11). Also the spiral design creates swirl of the air at high pressure providing better cushioning effect to the cable, enabling the speedier installation of the cable. Due to reduction of the contact surface and enhanced air cushioning effect have reduced possibilities of damage to the inner surface (14) and conduit (11) considerably.
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During installation of the optical fiber cables using the conduit of the present invention following results are obtained in respect of speed of installation and length of cable.
i. Due to ribbed design of the inner surface of the conduit, installation speed of as high as 10 minutes/ Kilometer has been achieved which is 3 times better than the speed achieved by the prior art conduit.
ii. The reduced friction between the conduit and cable has enabled installation of the cable to a length of 3 kilometers in a single operation which is three time greater length of the cable being installed using conduit of the prior art.
From the above results it is clear that the conduit of the present invention reduces the time and the cost of installation as compare to prior art conduit.
The conduit of the present invention is manufactured by a process known as "co-extrusion" process. In this process the outer surface of HDPE And inner surface of polymer compound containing silicon are concentrically extruded.
Industrial Applicability:
The conduit of the present invention serves two primary industries: communications (telephone, CATV, data transmission) and electrical (power transmission).
The present invention is not limited to the above described embodiments, and various alterations, modifications, and / or alternative applications of the invention may be possible, if desired, without departing from the scope and spirit of the invention which can be read from the claims and the entire specification. All these possible alterations, modifications, and / or alternative applications of the invention
are also intended to be within technical scope of the present invention.
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WE CLAIM:
1. A conduit used for laying of optical fiber cable comprises:
a hollow tubular body for receiving an optical fiber through it during laying operation, said tubular body consists of outer surface and inner surface, said outer surface is made up of high density poly-ethylene material and said inner surface is made up of a polymer compound containing silicon;
wherein said inner surface consists of a plurality of ribs along the periphery, said ribs are of spiral shape so that when optical fiber cable travels through said inner surface of said conduit the ribs reduces the frictional contact between optical fiber cable & conduit and provides cushioning effect to the cable for speedier installation.
2. A conduit used for laying of optical fiber cable as claimed in claim 1 wherein said tubular body has outer diameter of at least 40mm.
3. A conduit used for laying of optical fiber cable as claimed in claim 1 wherein said tubular body has inner diameter of at least 34mm.
4. A conduit used for laying of optical fiber cable as claimed in claim 1 wherein the thickness of said silicon layer is about 0.02 to 0.07mm.
5. A conduit used for laying of optical fiber cable as claimed in claim 1 wherein pitch of spiral rib is 3.45mm.
6. A conduit used for laying of optical fiber cable as claimed in claim 1 wherein it consists of 28 ribs along the periphery of the inner surface.
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7. A conduit used for laying of optical fiber cable as hereinbefore described and illustrated by accompanying drawings.
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Dated this 27th day of January, 2007.